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Int. J. Mol. Sci., Volume 12, Issue 3 (March 2011), Pages 1431-2087

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Open AccessArticle Overcoming the Recalcitrance for the Conversion of Kenaf Pulp to Glucose via Microwave-Assisted Pre-Treatment Processes
Int. J. Mol. Sci. 2011, 12(3), 1451-1463; doi:10.3390/ijms12031451
Received: 25 January 2011 / Revised: 11 February 2011 / Accepted: 21 February 2011 / Published: 24 February 2011
Cited by 10 | PDF Full-text (447 KB) | HTML Full-text | XML Full-text
Abstract
This study evaluates the pre-treatment of cellulose from kenaf plant to yield sugar precursors for the production of ethanol or butanol for use as biofuel additives. In order to convert the crystalline cellulosic form to the amorphous form that can undergo enzymatic [...] Read more.
This study evaluates the pre-treatment of cellulose from kenaf plant to yield sugar precursors for the production of ethanol or butanol for use as biofuel additives. In order to convert the crystalline cellulosic form to the amorphous form that can undergo enzymatic hydrolysis of the glycosidic bond to yield sugars, kenaf pulp samples were subjected to two different pre-treatment processes. In the acid pre-treatment, the pulp samples were treated with 37.5% hydrochloric acid in the presence of FeCl3 at 50 °C or 90 °C whereas in the alkaline method, the pulp samples were treated with 25% sodium hydroxide at room temperature and with 2% or 5% sodium hydroxide at 50 °C. Microwave-assisted NaOH-treatment of the cellulose was also investigated and demonstrated to be capable of producing high glucose yield without adverse environmental impact by circumventing the use of large amounts of concentrated acids i.e., 83–85% phosphoric acid employed in most digestion processes. The treated samples were digested with the cellulase enzyme from Trichoderma reesei. The amount of glucose produced was quantified using the QuantichromTM glucose bioassay for assessing the efficiency of glucose production for each of the treatment processes. The microwave-assisted alkaline pre-treatment processes conducted at 50 °C were found to be the most effective in the conversion of the crystalline cellulose to the amorphous form based on the significantly higher yields of sugar produced by enzymatic hydrolysis compared to the untreated sample. Full article
(This article belongs to the Special Issue Advances in Green Chemistry and Sustainable Chemistry 2011)
Open AccessArticle pH Dependent Molecular Self-Assembly of Octaphosphonate Porphyrin of Nanoscale Dimensions: Nanosphere and Nanorod Aggregates
Int. J. Mol. Sci. 2011, 12(3), 1464-1473; doi:10.3390/ijms12031464
Received: 27 January 2011 / Revised: 17 February 2011 / Accepted: 22 February 2011 / Published: 24 February 2011
Cited by 12 | PDF Full-text (342 KB) | HTML Full-text | XML Full-text
Abstract
Self-assembled nanostructures of zwitterionic octaphosphanatoporphyrin 1, of either nanoparticles or nanorods, depending on small changes in the pH, is demonstrated based on the J-aggregates. Porphyrin 1 self-assembled into nanosphere aggregates with a diameter of about 70–80 nm in the pH range [...] Read more.
Self-assembled nanostructures of zwitterionic octaphosphanatoporphyrin 1, of either nanoparticles or nanorods, depending on small changes in the pH, is demonstrated based on the J-aggregates. Porphyrin 1 self-assembled into nanosphere aggregates with a diameter of about 70–80 nm in the pH range 5–7, and nanorod aggregates were observed at pH 8.5. Hydrogen bonding, p-p stacking and hydrophilic interactions play important roles in the formation of this nanostructure morphology. Nanostructures were characterized by UV/Vis absorbance, fluorescence, atomic force microscopy (AFM) and transmission electron microscopy (TEM). This interesting pH dependent self-assembly phenomenon could provide a basis for development of novel biomaterials. Full article
(This article belongs to the Special Issue Molecular Self-Assembly)
Open AccessArticle Use of a Reflectance Spectroscopy Accessory for Optical Characterization of ZnO-Bi2O3-TiO2 Ceramics
Int. J. Mol. Sci. 2011, 12(3), 1496-1504; doi:10.3390/ijms12031496
Received: 11 December 2010 / Accepted: 17 February 2011 / Published: 25 February 2011
Cited by 2 | PDF Full-text (432 KB) | HTML Full-text | XML Full-text
Abstract
The optical band-gap energy (Eg) is an important feature of semiconductors which determines their applications in optoelectronics. Therefore, it is necessary to investigate the electronic states of ceramic ZnO and the effect of doped impurities under different processing conditions. [...] Read more.
The optical band-gap energy (Eg) is an important feature of semiconductors which determines their applications in optoelectronics. Therefore, it is necessary to investigate the electronic states of ceramic ZnO and the effect of doped impurities under different processing conditions. Eg of the ceramic ZnO + xBi2O3 + xTiO2, where x = 0.5 mol%, was determined using a UV-Vis spectrophotometer attached to a Reflectance Spectroscopy Accessory for powdered samples. The samples was prepared using the solid-state route and sintered at temperatures from 1140 to 1260 °C for 45 and 90 minutes. Eg was observed to decrease with an increase of sintering temperature. XRD analysis indicated hexagonal ZnO and few small peaks of intergranular layers of secondary phases. The relative density of the sintered ceramics decreased and the average grain size increased with the increase of sintering temperature. Full article
(This article belongs to the Section Material Sciences and Nanotechnology)
Open AccessArticle IL8 and Cathepsin B as Melanoma Serum Biomarkers
Int. J. Mol. Sci. 2011, 12(3), 1505-1518; doi:10.3390/ijms12031505
Received: 3 December 2010 / Revised: 15 February 2011 / Accepted: 22 February 2011 / Published: 25 February 2011
Cited by 22 | PDF Full-text (641 KB) | HTML Full-text | XML Full-text
Abstract
Melanoma accounts for only a small portion of skin cancer but it is associated with high mortality. Melanoma serum biomarkers that may aid early diagnosis or guide therapy are needed clinically. However, studies of serum biomarkers have often been hampered by the serum interference that causes false readouts in immunological tests. Here we show that, after using a special buffer to eliminate the serum interference, IL-8 and cathepsin B levels were significantly elevated in melanoma patients (p < 0.05). More importantly, the combination of IL-8 and cathepsin B were also studied as a prognosis marker for melanoma mortality. Our study provides a novel approach to examine serum biomarkers. Full article
(This article belongs to the Special Issue Biomarkers)
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Open AccessArticle Zeranol Down-Regulates p53 Expression in Primary Cultured Human Breast Cancer Epithelial Cells through Epigenetic Modification
Int. J. Mol. Sci. 2011, 12(3), 1519-1532; doi:10.3390/ijms12031519
Received: 25 January 2011 / Revised: 30 January 2011 / Accepted: 12 February 2011 / Published: 25 February 2011
Cited by 3 | PDF Full-text (313 KB) | HTML Full-text | XML Full-text
Abstract
Epidemiological studies have suggested that there are many risk factors associated with breast cancer. Silencing tumor suppressor genes through epigenetic alterations play critical roles in breast cancer initiation, promotion and progression. As a growth promoter, Zeranol (Z) has been approved by the [...] Read more.
Epidemiological studies have suggested that there are many risk factors associated with breast cancer. Silencing tumor suppressor genes through epigenetic alterations play critical roles in breast cancer initiation, promotion and progression. As a growth promoter, Zeranol (Z) has been approved by the FDA and is widely used to enhance the growth of beef cattle in the United States. However, the safety of Z use as a growth promoter is still under debate. In order to provide more evidence to clarify this critical health issue, the current study investigated the effect of Z on the proliferation of primary cultured human normal and cancerous breast epithelial cells (PCHNBECs and PCHBCECs, respectively) isolated from the same patient using MTS assay, RT-PCR and Western blot analysis. We also conducted an investigation regarding the mechanisms that might be involved. Our results show that Z is more potent to stimulate PCHBCEC growth than PCHNBEC growth. The stimulatory effects of Z on PCHBCECs and PCHBCECs may be mediated by its down-regulating expression of the tumor suppressor gene p53 at the mRNA and protein levels. Further investigation showed that the expression of DNA methylatransferase 1 mRNA and protein levels is up-regulated by treatment with Z in PCHBCECs as compared to PCHNBECs, which suggests a role of Z in epigenetic modification involved in the regulation of p53 gene expression in PCHBCECs. Our experimental results imply the potentially adverse health effect of Z in breast cancer development. Further study is continuing in our laboratory. Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
Open AccessArticle Distribution and Molecular Characterization of β-Glucans from Hull-Less Barley Bran, Shorts and Flour
Int. J. Mol. Sci. 2011, 12(3), 1563-1574; doi:10.3390/ijms12031563
Received: 19 December 2010 / Revised: 16 February 2011 / Accepted: 18 February 2011 / Published: 28 February 2011
Cited by 8 | PDF Full-text (325 KB) | HTML Full-text | XML Full-text
Abstract
Six hull-less barley cultivars widely grown in China were roller-milled to produce bran, shorts and flour fractions. The distribution and molecular characteristics of β-glucans from the three roller-milled fractions were investigated. The β-glucan contents in the six hull-less barley cultivars varied from [...] Read more.
Six hull-less barley cultivars widely grown in China were roller-milled to produce bran, shorts and flour fractions. The distribution and molecular characteristics of β-glucans from the three roller-milled fractions were investigated. The β-glucan contents in the six hull-less barley cultivars varied from 4.96% to 7.62%. For all the six cultivars, the shorts fraction contained the highest concentration of β-glucan (8.12–13.01%), followed by bran (6.15–7.58%) and flour (2.48–2.95%). Crude β-glucans were prepared from the three roller-milled fractions using aqueous sodium carbonate (pH 10). These preparations contained 45.38–71.41% β-glucan, 10.81–17.26% arabinoxylan, 2.6–9.6% protein, 2.7–9.0% starch, and 5.23–9.68% ash. Purification using a-amylase and β-xylanase in combination with pH adjustment and dialysis produced high purity β-glucan preparations (91–95%). The molecular weight (Mw) of β-glucan preparations from roller-milled fractions ranged from 117,600 to 852,400 g/mol. β-Glucan from flour had higher Mw than those from shorts and bran within the same cultivar, and β-glucan preparations from bran had the lowest Mw. Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
Open AccessArticle Cancer Stem-Like Cells Enriched in Panc-1 Spheres Possess Increased Migration Ability and Resistance to Gemcitabine
Int. J. Mol. Sci. 2011, 12(3), 1595-1604; doi:10.3390/ijms12031595
Received: 14 January 2011 / Revised: 1 February 2011 / Accepted: 17 February 2011 / Published: 1 March 2011
Cited by 26 | PDF Full-text (268 KB) | HTML Full-text | XML Full-text
Abstract
Pancreatic cancer is one of the most lethal malignancies with poor prognosis. Previously, we found that a subpopulation of cancer stem cells (CSCs) in the Panc-1 pancreatic cancer cell line could propagate to form spheres. Here we characterized the malignant phenotypes of [...] Read more.
Pancreatic cancer is one of the most lethal malignancies with poor prognosis. Previously, we found that a subpopulation of cancer stem cells (CSCs) in the Panc-1 pancreatic cancer cell line could propagate to form spheres. Here we characterized the malignant phenotypes of the pancreatic cancer stem CD44+/CD24+ cells, which were enriched under sphere forming conditions as analyzed by flow cytometry. These cells demonstrated increased resistance to gemcitabine and increased migration ability. Moreover, these cells exhibited epithelial to mesenchymal transition characterized by a decreased level of the epithelial marker E-cadherin and an increased level of the mesenchymal marker vimentin. Notably, abnormal expression of Bmi-1, ABCG2, Cyclin D1 and p16 were found in Panc-1 CSCs. Our results suggest that targeted inhibition of CSCs represents a novel therapeutic approach to overcome chemoresistance and metastasis of pancreatic cancer. Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
Open AccessArticle Combined 3D-QSAR Modeling and Molecular Docking Studies on Pyrrole-Indolin-2-ones as Aurora A Kinase Inhibitors
Int. J. Mol. Sci. 2011, 12(3), 1605-1624; doi:10.3390/ijms12031605
Received: 26 January 2011 / Accepted: 28 February 2011 / Published: 1 March 2011
Cited by 8 | PDF Full-text (2425 KB) | HTML Full-text | XML Full-text
Abstract
Aurora kinases have emerged as attractive targets for the design of anticancer drugs. 3D-QSAR (comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA)) and Surflex-docking studies were performed on a series of pyrrole-indoline-2-ones as Aurora A inhibitors. The CoMFA [...] Read more.
Aurora kinases have emerged as attractive targets for the design of anticancer drugs. 3D-QSAR (comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA)) and Surflex-docking studies were performed on a series of pyrrole-indoline-2-ones as Aurora A inhibitors. The CoMFA and CoMSIA models using 25 inhibitors in the training set gave r2cv values of 0.726 and 0.566, and r2 values of 0.972 and 0.984, respectively. The adapted alignment method with the suitable parameters resulted in reliable models. The contour maps produced by the CoMFA and CoMSIA models were employed to rationalize the key structural requirements responsible for the activity. Surflex-docking studies revealed that the sulfo group, secondary amine group on indolin-2-one, and carbonyl of 6,7-dihydro-1H-indol-4(5H)-one groups were significant for binding to the receptor, and some essential features were also identified. Based on the 3D-QSAR and docking results, a set of new molecules with high predicted activities were designed. Full article
(This article belongs to the Section Physical Chemistry, Theoretical and Computational Chemistry)
Open AccessArticle Photopyroelectric Spectroscopic Studies of ZnO-MnO2-Co3O4-V2O5 Ceramics
Int. J. Mol. Sci. 2011, 12(3), 1625-1632; doi:10.3390/ijms12031625
Received: 4 January 2011 / Revised: 9 February 2011 / Accepted: 16 February 2011 / Published: 3 March 2011
Cited by 3 | PDF Full-text (353 KB) | HTML Full-text | XML Full-text
Abstract
Photopyroelectric (PPE) spectroscopy is a nondestructive tool that is used to study the optical properties of the ceramics (ZnO + 0.4MnO2 + 0.4Co3O4 + xV2O5), x = 0–1 mol%. Wavelength of incident light, modulated [...] Read more.
Photopyroelectric (PPE) spectroscopy is a nondestructive tool that is used to study the optical properties of the ceramics (ZnO + 0.4MnO2 + 0.4Co3O4 + xV2O5), x = 0–1 mol%. Wavelength of incident light, modulated at 10 Hz, was in the range of 300–800 nm. PPE spectrum with reference to the doping level and sintering temperature is discussed. Optical energy band-gap (Eg) was 2.11 eV for 0.3 mol% V2O5 at a sintering temperature of 1025 °C as determined from the plot (ρhυ)2 versus . With a further increase in V2O5, the value of Eg was found to be 2.59 eV. Steepness factor ‘σA’ and ‘σB’, which characterize the slope of exponential optical absorption, is discussed with reference to the variation of Eg. XRD, SEM and EDAX are also used for characterization of the ceramic. For this ceramic, the maximum relative density and grain size was observed to be 91.8% and 9.5 μm, respectively. Full article
(This article belongs to the Section Material Sciences and Nanotechnology)
Open AccessArticle Preliminary Study of Conformation and Drug Release Mechanism of Doxorubicin-Conjugated Glycol Chitosan, via cis-Aconityl Linkage, by Molecular Modeling
Int. J. Mol. Sci. 2011, 12(3), 1672-1683; doi:10.3390/ijms12031672
Received: 29 January 2011 / Revised: 20 February 2011 / Accepted: 1 March 2011 / Published: 4 March 2011
Cited by 7 | PDF Full-text (560 KB) | HTML Full-text | XML Full-text
Abstract
An investigation of the structure and drug release mechanism of a drug delivery system is proposed on the basis of semi-empirical and ab initio computations in vacuum stage. Cis-aconityl linkage is used to improve the interaction between an anti-cancer agent, doxorubicin, [...] Read more.
An investigation of the structure and drug release mechanism of a drug delivery system is proposed on the basis of semi-empirical and ab initio computations in vacuum stage. Cis-aconityl linkage is used to improve the interaction between an anti-cancer agent, doxorubicin, and a glycol chitosan biopolymer. It has been found that the doxorubicin-conjugated glycol chitosan carrier has more stability. The stability is increased when the lengths of the polyethylene glycol (PEG) chains in the glycol chitosan biopolymer are increased. Cis-aconityl can release doxorubicin under appropriate environmental conditions. Relative energies of this mechanism in an acid condition, as determined by B3LYP/6-31G//PM3, are 122.41, 119.27, 160.18 and 222.22 kcal/mol, and by the B3LYP/6-31G//HF/6-31G method are 54.23, 109.28, 219.98 and 980.49 kcal/mol, with mono-, di-, tri-, and quanta-ethylene glycol, respectively. In a normal condition, the relative energies are above 300 kcal/mol for all reactions. Therefore, cis-aconityl will release doxorubicin in an acid solution but not in a normal condition. The glycol chitosan polymer can be degraded in an acid solution as well. Long PEG chains influence the release mechanism of doxorubicin. The proposed length of the PEG chain is di-ethylene glycol. These simulation results agree well with various reported experimental data. Full article
(This article belongs to the Section Material Sciences and Nanotechnology)
Open AccessArticle Docetaxel-Loaded Pluronic P123 Polymeric Micelles: in Vitro and in Vivo Evaluation
Int. J. Mol. Sci. 2011, 12(3), 1684-1696; doi:10.3390/ijms12031684
Received: 28 December 2010 / Revised: 26 February 2011 / Accepted: 28 February 2011 / Published: 4 March 2011
Cited by 33 | PDF Full-text (319 KB) | HTML Full-text | XML Full-text
Abstract
In this work, novel docetaxel (DTX) -loaded Tween 80-free Pluronic P123 (P123) micelles with improved therapeutic effect were developed. The freeze-dried DTX-loaded P123 micelles (DTX-micelles) were analyzed by HPLC, TEM and DLS to determine the DTX loading, micelle morphology, size, respectively. The in vitro cytotoxic activity of DTX-micelles in HepG2, A549 and malignant melanoma B16 cells were evaluated by MTT assay. The corresponding in vivo antitumor efficacy was assessed in Kunming mice bearing B16 tumor after intravenous administration. The DTX-loading and efficiency into the micelles were 2.12 ± 0.09% and 86.34 ± 3.32%, respectively. The DTX-micelles were spherical with a mean particle size of 50.7 nm and size distribution from 22 to 84 nm, which suggested that they should be able to selectively accumulate in solid tumors by means of EPR effect, with a zeta potential of −12.45 ± 3.24 mV. The in vitro release behavior of DTX from DTX-micelles followed the Weibull equation. Compared with Duopafei®, DTX-micelles showed higher cytotoxicity against HepG2 (P < 0.01), A549 (P < 0.05) and B16 (P < 0.01) cells. In addition, DTX-micelles exhibited remarkable antitumor activity and reduced toxicity on B16 tumor in vivo. The tumor inhibition rates (TIR) of DTX-micelles was 91.6% versus 76.3% of Duopafei® (P < 0.01). These results suggested that P123 micelles might be considered as an effective DTX delivery system. Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
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Open AccessArticle Remarks on Muscle Contraction Mechanism II. Isometric Tension Transient and Isotonic Velocity Transient
Int. J. Mol. Sci. 2011, 12(3), 1697-1726; doi:10.3390/ijms12031697
Received: 19 December 2010 / Revised: 20 February 2011 / Accepted: 22 February 2011 / Published: 4 March 2011
PDF Full-text (422 KB) | HTML Full-text | XML Full-text
Abstract
Mitsui and Ohshima (2008) criticized the power-stroke model for muscle contraction and proposed a new model. In the new model, about 41% of the myosin heads are bound to actin filaments, and each bound head forms a complex MA3 with three [...] Read more.
Mitsui and Ohshima (2008) criticized the power-stroke model for muscle contraction and proposed a new model. In the new model, about 41% of the myosin heads are bound to actin filaments, and each bound head forms a complex MA3 with three actin molecules A1, A2 and A3 forming the crossbridge. The complex translates along the actin filament cooperating with each other. The new model well explained the experimental data on the steady filament sliding. As an extension of the study, the isometric tension transient and isotonic velocity transient are investigated. Statistical ensemble of crossbridges is introduced, and variation of the binding probability of myosin head to A1 is considered. When the binding probability to A1 is zero, the Hill-type force-velocity relation is resulted in. When the binding probability to A1 becomes finite, the deviation from the Hill-type force-velocity relation takes place, as observed by Edman (1988). The characteristics of the isometric tension transient observed by Ford, Huxley and Simmons (1977) and of the isotonic velocity transient observed by Civan and Podolsky (1966) are theoretically reproduced. Ratios of the extensibility are estimated as 0.22 for the crossbridge, 0.26 for the myosin filament and 0.52 for the actin filament, in consistency with the values determined by X-ray diffraction by Wakabayashi et al. (1994). Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
Open AccessArticle Evaluation of Potential Reference Genes for Relative Quantification by RT-qPCR in Different Porcine Tissues Derived from Feeding Studies
Int. J. Mol. Sci. 2011, 12(3), 1727-1734; doi:10.3390/ijms12031727
Received: 24 December 2010 / Revised: 29 January 2011 / Accepted: 25 February 2011 / Published: 7 March 2011
Cited by 13 | PDF Full-text (139 KB) | HTML Full-text | XML Full-text
Abstract
Five potential reference genes for RT-qPCR application, namely histone H3, beta-actin, GAPDH, ubiquitin and 18S rRNA, were evaluated for normalization of gene expression in four selected tissues (liver, kidney, thyroid and abdominal fat). Tissues were derived from fattening pigs exposed to different [...] Read more.
Five potential reference genes for RT-qPCR application, namely histone H3, beta-actin, GAPDH, ubiquitin and 18S rRNA, were evaluated for normalization of gene expression in four selected tissues (liver, kidney, thyroid and abdominal fat). Tissues were derived from fattening pigs exposed to different amounts and type of dietary iodine. Two software applications (geNorm and NormFinder) were used to evaluate the stability of the potential reference genes. All studied genes displayed high expression stability but different stability patterns between the investigated tissues. The results suggest GAPDH and 18S rRNA as reference genes applicable in all tissues investigated. Beta-actin and histone H3 are suitable reference genes for all tissues investigated except fat. In contrast, ubiquitin should be excluded from use as a reference gene in the porcine tissues analyzed due to variations in expression levels, despite the good expression stability. Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
Open AccessArticle Synthesis of Molecularly Imprinted Polymers for Amino Acid Derivates by Using Different Functional Monomers
Int. J. Mol. Sci. 2011, 12(3), 1735-1743; doi:10.3390/ijms12031735
Received: 14 January 2011 / Revised: 1 February 2011 / Accepted: 1 March 2011 / Published: 7 March 2011
Cited by 22 | PDF Full-text (342 KB) | HTML Full-text | XML Full-text
Abstract
Fmoc-3-nitrotyrosine (Fmoc-3-NT) molecularly imprinted polymers (MIPs) were synthesized to understand the influence of several functional monomers on the efficiency of the molecular imprinting process. Acidic, neutral and basic functional monomers, such as acrylic acid (AA), methacrylic acid (MAA), methacrylamide (MAM), 2-vinylpyridine (2-VP), [...] Read more.
Fmoc-3-nitrotyrosine (Fmoc-3-NT) molecularly imprinted polymers (MIPs) were synthesized to understand the influence of several functional monomers on the efficiency of the molecular imprinting process. Acidic, neutral and basic functional monomers, such as acrylic acid (AA), methacrylic acid (MAA), methacrylamide (MAM), 2-vinylpyridine (2-VP), 4-vinylpyridine (4-VP), have been used to synthesize five different polymers. In this study, the MIPs were tested in batch experiments by UV-visible spectroscopy in order to evaluate their binding properties. The MIP prepared with 2-VP exhibited the highest binding affinity for Fmoc-3NT, for which Scatchard analysis the highest association constant (2.49 × 104 M−1) was obtained. Furthermore, titration experiments of Fmoc-3NT into acetonitrile solutions of 2-VP revealed a stronger bond to the template, such that a total interaction is observed. Non-imprinted polymers as control were prepared and showed no binding affinities for Fmoc-3NT. The results are indicative of the importance of ionic bonds formed between the –OH residues of the template molecule and the pyridinyl groups of the polymer matrix. In conclusion, 2-VP assists to create a cavity which allows better access to the analytes. Full article
(This article belongs to the Section Material Sciences and Nanotechnology)
Open AccessArticle Experimental Construction of BMP2 and VEGF Gene Modified Tissue Engineering Bone in Vitro
Int. J. Mol. Sci. 2011, 12(3), 1744-1755; doi:10.3390/ijms12031744
Received: 31 December 2010 / Revised: 22 February 2011 / Accepted: 1 March 2011 / Published: 7 March 2011
Cited by 9 | PDF Full-text (500 KB) | HTML Full-text | XML Full-text
Abstract
The purpose of this study was to investigate the feasibility and advantages of constructing a novel tissue engineering bone, using β-tricalcium phosphate (β-TCP) and rat bone marrow mesenchymal stem cells (MSCs), modified with human bone morphogenetic protein 2 gene (hBMP2) and human vascular endothelial growth factor 165 gene (hVEGF165), through lentiviral transfection. Both genes were successfully co-expressed in the co-transfection group for up to eight weeks confirmed by enzyme-linked immunosorbent assay (ELISA). After seeding MSCs onto the scaffolds, scanning electron microscopy (SEM) observation showed that MSCs grew and proliferated well in co-transfection group at 7 and 14 days. There was no significant difference among all the groups in hoechst DNA assay for cell proliferation for 14 days after cell seeding (P > 0.05), but the highest alkaline phosphatase (ALP) activity was observed in the co-transfection group at 14 days after cell seeding (p < 0.01). These results demonstrated that it was advantageous to construct tissue engineering bone using β-TCP combined with MSCs lentivirally co-transfected with BMP2 and VEGF165, providing an innovative way for treating bone defects. Full article
(This article belongs to the Section Material Sciences and Nanotechnology)
Open AccessArticle The Effect of Zn-Al-Hydrotalcites Composited with Calcium Stearate and β-Diketone on the Thermal Stability of PVC
Int. J. Mol. Sci. 2011, 12(3), 1756-1766; doi:10.3390/ijms12031756
Received: 26 January 2011 / Revised: 9 February 2011 / Accepted: 7 March 2011 / Published: 8 March 2011
Cited by 9 | PDF Full-text (389 KB) | HTML Full-text | XML Full-text
Abstract
A clean-route synthesis of Zn-Al-hydrotalcites (Zn-Al-LDHs) using zinc oxide and sodium aluminate solution has been developed. The as-obtained materials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The effects of metal ions at different [...] Read more.
A clean-route synthesis of Zn-Al-hydrotalcites (Zn-Al-LDHs) using zinc oxide and sodium aluminate solution has been developed. The as-obtained materials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The effects of metal ions at different molar ratios on the performance of hydrotalcites were discussed. The results showed that the Zn-Al-hydrotalcites can be successfully synthesized at three different Zn/Al ratios of 3:1, 2:1 and 1:1. Thermal aging tests of polyvinyl chloride (PVC) mixed with Zn-Al-LDHs, calcium stearate (CaSt2) and β-diketone were carried out in a thermal aging test box by observing the color change. The results showed that Zn-Al-LDHs can not only enhance the stability of PVC significantly due to the improved capacity of HCl-adsorption but also increase the initial stability and ensure good-initial coloring due to the presence of the Zn element. The effects of various amounts of Zn-Al-LDHs, CaSt2 and β-diketone on the thermal stability of PVC were discussed. The optimum composition was determined to be 0.1 g Zn-Al-LDHs, 0.15 g CaSt2 and 0.25 g β-diketone in 5 g PVC. Full article
(This article belongs to the Section Material Sciences and Nanotechnology)
Open AccessArticle Importance of the Long-Chain Fatty Acid Beta-Hydroxylating Cytochrome P450 Enzyme YbdT for Lipopeptide Biosynthesis in Bacillus subtilis Strain OKB105
Int. J. Mol. Sci. 2011, 12(3), 1767-1786; doi:10.3390/ijms12031767
Received: 9 December 2010 / Revised: 8 February 2011 / Accepted: 3 March 2011 / Published: 8 March 2011
Cited by 2 | PDF Full-text (451 KB) | HTML Full-text | XML Full-text
Abstract
Bacillus species produce extracellular, surface-active lipopeptides such as surfactin that have wide applications in industry and medicine. The steps involved in the synthesis of 3-hydroxyacyl-coenzyme A (CoA) substrates needed for surfactin biosynthesis are not understood. Cell-free extracts of Bacillus subtilis strain OKB105 [...] Read more.
Bacillus species produce extracellular, surface-active lipopeptides such as surfactin that have wide applications in industry and medicine. The steps involved in the synthesis of 3-hydroxyacyl-coenzyme A (CoA) substrates needed for surfactin biosynthesis are not understood. Cell-free extracts of Bacillus subtilis strain OKB105 synthesized lipopeptide biosurfactants in presence of L-amino acids, myristic acid, coenzyme A, ATP, and H2O2, which suggested that 3-hydroxylation occurs prior to CoA ligation of the long chain fatty acids (LCFAs). We hypothesized that YbdT, a cytochrome P450 enzyme known to beta-hydroxylate LCFAs, functions to form 3-hydroxy fatty acids for lipopeptide biosynthesis. An in-frame mutation of ybdT was constructed and the resulting mutant strain (NHY1) produced predominantly non-hydroxylated lipopeptide with diminished biosurfactant and beta-hemolytic activities. Mass spectrometry showed that 95.6% of the fatty acids in the NHY1 biosurfactant were non-hydroxylated compared to only ~61% in the OKB105 biosurfactant. Cell-free extracts of the NHY1 synthesized surfactin containing 3-hydroxymyristic acid from 3-hydroxymyristoyl-CoA at a specific activity similar to that of the wild type (17 ± 2 versus 17.4 ± 6 ng biosurfactant min−1·ng·protein−1, respectively). These results showed that the mutation did not affect any function needed to synthesize surfactin once the 3-hydroxyacyl-CoA substrate was formed and that YbdT functions to supply 3-hydroxy fatty acid for surfactin biosynthesis. The fact that YbdT is a peroxidase could explain why biosurfactant production is rarely observed in anaerobically grown Bacillus species. Manipulation of LCFA specificity of YbdT could provide a new route to produce biosurfactants with activities tailored to specific functions. Full article
(This article belongs to the Special Issue Biosurfactants)
Open AccessArticle Novel Application of Cyclolipopeptide Amphisin: Feasibility Study as Additive to Remediate Polycyclic Aromatic Hydrocarbon (PAH) Contaminated Sediments
Int. J. Mol. Sci. 2011, 12(3), 1787-1806; doi:10.3390/ijms12031787
Received: 3 November 2010 / Revised: 15 February 2011 / Accepted: 2 March 2011 / Published: 9 March 2011
Cited by 6 | PDF Full-text (703 KB) | HTML Full-text | XML Full-text
Abstract
To decontaminate dredged harbor sediments by bioremediation or electromigration processes, adding biosurfactants could enhance the bioavailability or mobility of contaminants in an aqueous phase. Pure amphisin from Pseudomonas fluorescens DSS73 displays increased effectiveness in releasing polycyclic aromatic hydrocarbons (PAHs) strongly adsorbed to [...] Read more.
To decontaminate dredged harbor sediments by bioremediation or electromigration processes, adding biosurfactants could enhance the bioavailability or mobility of contaminants in an aqueous phase. Pure amphisin from Pseudomonas fluorescens DSS73 displays increased effectiveness in releasing polycyclic aromatic hydrocarbons (PAHs) strongly adsorbed to sediments when compared to a synthetic anionic surfactant. Amphisin production by the bacteria in the natural environment was also considered. DSS73’s growth is weakened by three model PAHs above saturation, but amphisin is still produced. Estuarine water feeding the dredged material disposal site of a Norman harbor (France) allows both P. fluorescens DSS73 growth and amphisin production. Full article
(This article belongs to the Special Issue Biosurfactants)
Open AccessArticle Combined 3D-QSAR, Molecular Docking and Molecular Dynamics Study on Derivatives of Peptide Epoxyketone and Tyropeptin-Boronic Acid as Inhibitors Against the β5 Subunit of Human 20S Proteasome
Int. J. Mol. Sci. 2011, 12(3), 1807-1835; doi:10.3390/ijms12031807
Received: 24 January 2011 / Revised: 14 February 2011 / Accepted: 28 February 2011 / Published: 9 March 2011
Cited by 24 | PDF Full-text (2890 KB) | HTML Full-text | XML Full-text
Abstract
An abnormal ubiquitin-proteasome is found in many human diseases, especially in cancer, and has received extensive attention as a promising therapeutic target in recent years. In this work, several in silico models have been built with two classes of proteasome inhibitors (PIs) [...] Read more.
An abnormal ubiquitin-proteasome is found in many human diseases, especially in cancer, and has received extensive attention as a promising therapeutic target in recent years. In this work, several in silico models have been built with two classes of proteasome inhibitors (PIs) by using 3D-QSAR, homology modeling, molecular docking and molecular dynamics (MD) simulations. The study resulted in two types of satisfactory 3D-QSAR models, i.e., the CoMFA model (Q2 = 0.462, R2pred = 0.820) for epoxyketone inhibitors (EPK) and the CoMSIA model (Q2 = 0.622, R2pred = 0.821) for tyropeptin-boronic acid derivatives (TBA). From the contour maps, some key structural factors responsible for the activity of these two series of PIs are revealed. For EPK inhibitors, the N-cap part should have higher electropositivity; a large substituent such as a benzene ring is favored at the C6-position. In terms of TBA inhibitors, hydrophobic substituents with a larger size anisole group are preferential at the C8-position; higher electropositive substituents like a naphthalene group at the C3-position can enhance the activity of the drug by providing hydrogen bond interaction with the protein target. Molecular docking disclosed that residues Thr60, Thr80, Gly106 and Ser189 play a pivotal role in maintaining the drug-target interactions, which are consistent with the contour maps. MD simulations further indicated that the binding modes of each conformation derived from docking is stable and in accord with the corresponding structure extracted from MD simulation overall. These results can offer useful theoretical references for designing more potent PIs. Full article
(This article belongs to the Section Physical Chemistry, Theoretical and Computational Chemistry)
Open AccessArticle Dietary Sources of Fiber Intake and Its Association with Socio-Economic Factors among Flemish Preschool Children
Int. J. Mol. Sci. 2011, 12(3), 1836-1853; doi:10.3390/ijms12031836
Received: 3 January 2011 / Revised: 12 February 2011 / Accepted: 22 February 2011 / Published: 10 March 2011
Cited by 1 | PDF Full-text (320 KB) | HTML Full-text | XML Full-text
Abstract
The objectives were to assess total dietary fiber intake, identify the major sources of dietary fiber, and examine its association with socio-economic factors among Flemish preschoolers. Three-day estimated dietary records were collected from a representative sample of preschoolers 2.5–6.5 years old ( [...] Read more.
The objectives were to assess total dietary fiber intake, identify the major sources of dietary fiber, and examine its association with socio-economic factors among Flemish preschoolers. Three-day estimated dietary records were collected from a representative sample of preschoolers 2.5–6.5 years old (n = 661; 338 boys, 323 girls). The mean dietary fiber intake (13.4 g/d) was lower than the intake level recommended by the Belgian Superior Health Council (70% boys and 81% girls below the guidelines). The most important contributor was the group of bread and cereals (29.5%), followed by fruits (17.8%), potatoes and grains (16.0%), energy-dense, low-nutritious foods (12.4%), and vegetables (11.8%). Multiple linear regression analyses showed that total fiber intake was associated with maternal education and parents’ employment. Overall, fiber intakes from high-nutritious foods (vegetables and fruits) were higher in preschoolers of higher educated mothers and those with one or both parents being employed. In conclusion, the majority of the preschoolers had dietary fiber intakes below the recommended level. Hence, dietary fiber should be promoted among parents of preschoolers and low socio-economic status families should be addressed in particular. Full article
(This article belongs to the Special Issue Dietary Fibre: Biochemistry and Nutritional Science)
Open AccessArticle Separation and Purification of Sulforaphane from Broccoli by Solid Phase Extraction
Int. J. Mol. Sci. 2011, 12(3), 1854-1861; doi:10.3390/ijms12031854
Received: 10 February 2011 / Revised: 1 March 2011 / Accepted: 7 March 2011 / Published: 10 March 2011
Cited by 9 | PDF Full-text (195 KB) | HTML Full-text | XML Full-text
Abstract
A simple solid-phase extraction (SPE) method for the determination of sulforaphane in broccoli has been developed. The optimal conditions were found to be use of a silica SPE cartridge, and ethyl acetate and dichloromethane as washing and eluting solvents, respectively, which could [...] Read more.
A simple solid-phase extraction (SPE) method for the determination of sulforaphane in broccoli has been developed. The optimal conditions were found to be use of a silica SPE cartridge, and ethyl acetate and dichloromethane as washing and eluting solvents, respectively, which could eliminate interferences originating from the broccoli matrix. The extracts were sufficiently clean to be directly injected into high-performance liquid chromatography (HPLC) for further chromatographic analysis. Good linearity was obtained from 0.05 to 200 μg/mL (r = 0.998) for sulforaphane with the relative standard deviations less than 3.6%. The mean recoveries of sulforaphane from broccoli were more than 90.8% and the detection limit (S/N = 3:1) was 0.02 μg/mL. The SPE method provides a higher yield of sulforaphane from crude extracts compared to conventional liquid-liquid extraction. Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
Open AccessArticle Changes of Constituents and Activity to Apoptosis and Cell Cycle During Fermentation of Tea
Int. J. Mol. Sci. 2011, 12(3), 1862-1875; doi:10.3390/ijms12031862
Received: 26 January 2011 / Revised: 24 February 2011 / Accepted: 28 February 2011 / Published: 10 March 2011
Cited by 12 | PDF Full-text (547 KB) | HTML Full-text | XML Full-text
Abstract
Tea is believed to be beneficial for health, and the effects of the fermentation process on its contributions to apoptosis and cell cycle arrest of gastric cancer cells have not been completely investigated. In this study, the chemical components in green tea, [...] Read more.
Tea is believed to be beneficial for health, and the effects of the fermentation process on its contributions to apoptosis and cell cycle arrest of gastric cancer cells have not been completely investigated. In this study, the chemical components in green tea, black tea and pu-erh tea aqueous extracts were analyzed and compared. The polysaccharide and caffeine levels were substantially higher in the fermented black tea and pu-erh tea, while the polyphenol level was higher in the unfermented green tea. Hence, a treatment of tea aqueous extract and the components, which are emerging as promising anticancer agents, were pursued to determine whether this treatment could lead to enhance apoptosis and cell cycle arrest. In the human gastric cancer cell line SGC-7901, the cell viability and flow cytometry analysis for apoptotic cells indicated effects in a dose-dependent inhibition manner for the three tea treatment groups. The apoptosis rates were found to be elevated after 48 h of treatment with 31.2, 125, and 500 μg/mL of green tea extract, the higher catechins content may be involved in the mechanism. Cell cycle was arrested in S phase in the fermented black tea and pu-erh tea, and the populations were significantly decreased in G2/M phases, possibly due to the oxidation of tea polyphenols, which causes an increase of theabrownins. CCC-HEL-1 normal cells were not sensitive to tea extract. These findings suggest that the fermentation process causes changes of the compounds which might be involved in the changes of cell proliferation inhibition, apoptosis induction and cell cycle arrest. Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
Open AccessArticle Differential Responses to Blood Pressure and Oxidative Stress in Streptozotocin-Induced Diabetic Wistar-Kyoto Rats and Spontaneously Hypertensive Rats: Effects of Antioxidant (Honey) Treatment
Int. J. Mol. Sci. 2011, 12(3), 1888-1907; doi:10.3390/ijms12031888
Received: 14 November 2010 / Revised: 29 December 2010 / Accepted: 5 January 2011 / Published: 16 March 2011
Cited by 20 | PDF Full-text (334 KB) | HTML Full-text | XML Full-text
Abstract
Oxidative stress is implicated in the pathogenesis and/or complications of hypertension and/or diabetes mellitus. A combination of these disorders increases the risk of developing cardiovascular events. This study investigated the effects of streptozotocin (60 mg/kg; ip)-induced diabetes on blood pressure, oxidative stress and [...] Read more.
Oxidative stress is implicated in the pathogenesis and/or complications of hypertension and/or diabetes mellitus. A combination of these disorders increases the risk of developing cardiovascular events. This study investigated the effects of streptozotocin (60 mg/kg; ip)-induced diabetes on blood pressure, oxidative stress and effects of honey on these parameters in the kidneys of streptozotocin-induced diabetic Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). Diabetic WKY and SHR were randomized into four groups and received distilled water (0.5 mL) and honey (1.0 g/kg) orally once daily for three weeks. Control SHR had reduced malondialdehyde (MDA) and increased systolic blood pressure (SBP), catalase (CAT) activity, and total antioxidant status (TAS). SBP, activities of glutathione peroxidase (GPx) and glutathione reductase (GR) were elevated while TAS was reduced in diabetic WKY. In contrast, SBP, TAS, activities of GPx and GR were reduced in diabetic SHR. Antioxidant (honey) treatment further reduced SBP in diabetic SHR but not in diabetic WKY. It also increased TAS, GSH, reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio, activities of GPx and GR in diabetic SHR. These data suggest that differences in types, severity, and complications of diseases as well as strains may influence responses to blood pressure and oxidative stress. Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
Open AccessArticle Natural-Synthetic Hybrid Polymers Developed via Electrospinning: The Effect of PET in Chitosan/Starch System
Int. J. Mol. Sci. 2011, 12(3), 1908-1920; doi:10.3390/ijms12031908
Received: 17 January 2011 / Revised: 2 March 2011 / Accepted: 14 March 2011 / Published: 16 March 2011
Cited by 10 | PDF Full-text (641 KB) | HTML Full-text | XML Full-text
Abstract
Chitosan is an amino polysaccharide found in nature, which is biodegradable, nontoxic and biocompatible. It has versatile features and can be used in a variety of applications including films, packaging, and also in medical surgery. Recently a possibility to diversify chitosan properties [...] Read more.
Chitosan is an amino polysaccharide found in nature, which is biodegradable, nontoxic and biocompatible. It has versatile features and can be used in a variety of applications including films, packaging, and also in medical surgery. Recently a possibility to diversify chitosan properties has emerged by combining it with synthetic materials to produce novel natural-synthetic hybrid polymers. We have studied structural and thermophysical properties of chitosan + starch + poly(ethylene terephthalate) (Ch + S + PET) fibers developed via electrospinning. Properties of these hybrids polymers are compared with extant chitosan containing hybrids synthesized by electrospinning. Molecular interactions and orientation in the fibers are analyzed by infrared and Raman spectroscopies respectively, morphology by scanning electron microscopy and thermophysical properties by thermogravimetric analysis and differential scanning calorimetry. Addition of PET to Ch + S systems results in improved thermal stability at elevated temperatures. Full article
(This article belongs to the Special Issue Chitins)
Open AccessArticle Detecting Molecular Features of Spectra Mainly Associated with Structural and Non-Structural Carbohydrates in Co-Products from BioEthanol Production Using DRIFT with Uni- and Multivariate Molecular Spectral Analyses
Int. J. Mol. Sci. 2011, 12(3), 1921-1935; doi:10.3390/ijms12031921
Received: 7 January 2011 / Revised: 21 February 2011 / Accepted: 7 March 2011 / Published: 17 March 2011
Cited by 18 | PDF Full-text (562 KB) | HTML Full-text | XML Full-text
Abstract
The objective of this study was to use DRIFT spectroscopy with uni- and multivariate molecular spectral analyses as a novel approach to detect molecular features of spectra mainly associated with carbohydrate in the co-products (wheat DDGS, corn DDGS, blend DDGS) from bioethanol processing in comparison with original feedstock (wheat (Triticum), corn (Zea mays)). The carbohydrates related molecular spectral bands included: A_Cell (structural carbohydrates, peaks area region and baseline: ca. 1485–1188 cm−1), A_1240 (structural carbohydrates, peak area centered at ca. 1240 cm−1 with region and baseline: ca. 1292–1198 cm−1), A_CHO (total carbohydrates, peaks region and baseline: ca. 1187–950 cm-1), A_928 (non-structural carbohydrates, peak area centered at ca. 928 cm−1 with region and baseline: ca. 952–910 cm−1), A_860 (non-structural carbohydrates, peak area centered at ca. 860 cm−1 with region and baseline: ca. 880–827 cm-1), H_1415 (structural carbohydrate, peak height centered at ca. 1415 cm−1 with baseline: ca. 1485–1188 cm−1), H_1370 (structural carbohydrate, peak height at ca. 1370 cm−1 with a baseline: ca. 1485–1188 cm−1). The study shows that the grains had lower spectral intensity (KM Unit) of the cellulosic compounds of A_1240 (8.5 vs. 36.6, P < 0.05), higher (P < 0.05) intensities of the non-structural carbohydrate of A_928 (17.3 vs. 2.0) and A_860 (20.7 vs. 7.6) than their co-products from bioethanol processing. There were no differences (P > 0.05) in the peak area intensities of A_Cell (structural CHO) at 1292–1198 cm−1 and A_CHO (total CHO) at 1187–950 cm−1 with average molecular infrared intensity KM unit of 226.8 and 508.1, respectively. There were no differences (P > 0.05) in the peak height intensities of H_1415 and H_1370 (structural CHOs) with average intensities 1.35 and 1.15, respectively. The multivariate molecular spectral analyses were able to discriminate and classify between the corn and corn DDGS molecular spectra, but not wheat and wheat DDGS. This study indicated that the bioethanol processing changes carbohydrate molecular structural profiles, compared with the original grains. However, the sensitivities of different types of carbohydrates and different grains (corn and wheat) to the processing differ. In general, the bioethanol processing increases the molecular spectral intensities for the structural carbohydrates and decreases the intensities for the non-structural carbohydrates. Further study is needed to quantify carbohydrate related molecular spectral features of the bioethanol co-products in relation to nutrient supply and availability of carbohydrates. Full article
(This article belongs to the Special Issue Dietary Fibre: Biochemistry and Nutritional Science)
Open AccessArticle Synthesis, Characterization and Thermal Studies of Zn(II), Cd(II) and Hg(II) Complexes of N-Methyl-N-Phenyldithiocarbamate: The Single Crystal Structure of [(C6H5)(CH3)NCS2]4Hg2
Int. J. Mol. Sci. 2011, 12(3), 1964-1978; doi:10.3390/ijms12031964
Received: 25 January 2011 / Revised: 9 February 2011 / Accepted: 8 March 2011 / Published: 17 March 2011
Cited by 28 | PDF Full-text (596 KB) | HTML Full-text | XML Full-text
Abstract
Zn(II), Cd(II) and Hg(II) complexes of N-methyl-N-phenyl dithiocarbamate have been synthesized and characterized by elemental analysis and spectral studies (IR, 1H and 13C-NMR). The single crystal X-ray structure of the mercury complex revealed that the complex contains a Hg centre [...] Read more.
Zn(II), Cd(II) and Hg(II) complexes of N-methyl-N-phenyl dithiocarbamate have been synthesized and characterized by elemental analysis and spectral studies (IR, 1H and 13C-NMR). The single crystal X-ray structure of the mercury complex revealed that the complex contains a Hg centre with a distorted tetrahedral coordination sphere in which the dinuclear Hg complex resides on a crystallographic inversion centre and each Hg atom is coordinated to four S atoms from the dithiocarbamate moiety. One dithiocarbamate ligand acts as chelating ligand while the other acts as chelating bridging ligand between two Hg atoms, resulting in a dinuclear eight-member ring. The course of the thermal degradation of the complexes has been investigated using thermogravimetric and differential thermal analyses techniques. Thermogravimetric analysis of the complexes show a single weight loss to give MS (M = Zn, Cd, Hg) indicating that they might be useful as single source precursors for the synthesis of MS nanoparticles and thin films. Full article
(This article belongs to the Special Issue Metal Organic Frameworks)
Open AccessArticle Effect of Ligusticum wallichii Aqueous Extract on Oxidative Injury and Immunity Activity in Myocardial Ischemic Reperfusion Rats
Int. J. Mol. Sci. 2011, 12(3), 1991-2006; doi:10.3390/ijms12031991
Received: 10 January 2011 / Revised: 22 February 2011 / Accepted: 9 March 2011 / Published: 18 March 2011
Cited by 7 | PDF Full-text (179 KB) | HTML Full-text | XML Full-text
Abstract
We investigated the efficacy of Ligusticum wallichi aqueous extract (LWE) for myocardial protection against ischemia-reperfusion injury. Rats were fed for five weeks with either a control diet (sham and ischemia reperfusion (IR) model control groups) or a diet mixed with 0.2%, 0.4% [...] Read more.
We investigated the efficacy of Ligusticum wallichi aqueous extract (LWE) for myocardial protection against ischemia-reperfusion injury. Rats were fed for five weeks with either a control diet (sham and ischemia reperfusion (IR) model control groups) or a diet mixed with 0.2%, 0.4% or 0.6% Ligusticum wallichi extract. At the end of the five week period, hearts were excised and subjected to global ischemia for 30 min followed by reperfusion for 2 h. The hearts were compared for indices of oxidative stress and immunity activities. Administration of Ligusticum wallichi extract significantly decreased serum TNF-α, IL-6, IL-8, NO, MIP-1α, CRP and myocardium MDA levels, and serum CK, LDH and AST activities, and increased myocardium Na+-K+-ATPase, Ca2+-Mg2+-ATPase, NOS, SOD, CAT, GSH-Px and TAOC activities. The results indicate that Ligusticum wallichii extract treatment can enhance myocardial antioxidant status and improve the immunity profile in ischemic-reperfusion rats. Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
Open AccessArticle Continuous Spatial Tuning of Laser Emissions in a Full Visible Spectral Range
Int. J. Mol. Sci. 2011, 12(3), 2007-2018; doi:10.3390/ijms12032007
Received: 26 January 2011 / Revised: 4 March 2011 / Accepted: 18 March 2011 / Published: 21 March 2011
Cited by 4 | PDF Full-text (910 KB) | HTML Full-text | XML Full-text
Abstract
In order to achieve a continuous tuning of laser emission, the authors designed and fabricated three types of cholesteric liquid crystal cells with pitch gradient, a wedge cell with positive slope, a wedge cell with negative slope, and a parallel cell. The [...] Read more.
In order to achieve a continuous tuning of laser emission, the authors designed and fabricated three types of cholesteric liquid crystal cells with pitch gradient, a wedge cell with positive slope, a wedge cell with negative slope, and a parallel cell. The length of the cholesteric liquid crystal pitch could be elongated up to 10 nm, allowing the lasing behavior of continuous or discontinuous spatial tuning determined by the boundary conditions of the cholesteric liquid crystal cell. In the wedge cell with positive slope, the authors demonstrated a continuous spatial laser tuning in the near full visible spectral range, with a tuning resolution less than 1 nm by pumping with only a single 355 nm laser beam. This continuous tuning behavior is due to the fact that the concentration of pitch gradient matches the fixed helical pitch determined by the cell thickness. This characteristic continuous spatial laser tuning could be confirmed again by pumping with a 532 nm laser beam, over 90 nm in the visible spectral range. The scheme of the spatial laser tuning in the wedge cell bearing a pitch gradient enabled a route to designing small-sized optical devices that allow for a wide tunability of single-mode laser emissions. Full article
(This article belongs to the Special Issue Liquid Crystals 2011)
Open AccessArticle Amyloidogenic Properties of a D/N Mutated 12 Amino Acid Fragment of the C-Terminal Domain of the Cholesteryl-Ester Transfer Protein (CETP)
Int. J. Mol. Sci. 2011, 12(3), 2019-2035; doi:10.3390/ijms12032019
Received: 10 January 2011 / Revised: 2 March 2011 / Accepted: 14 March 2011 / Published: 21 March 2011
Cited by 5 | PDF Full-text (1328 KB) | HTML Full-text | XML Full-text
Abstract
The cholesteryl-ester transfer protein (CETP) facilitates the transfer of cholesterol esters and triglycerides between lipoproteins in plasma where the critical site for its function is situated in the C-terminal domain. Our group has previously shown that this domain presents conformational changes [...] Read more.
The cholesteryl-ester transfer protein (CETP) facilitates the transfer of cholesterol esters and triglycerides between lipoproteins in plasma where the critical site for its function is situated in the C-terminal domain. Our group has previously shown that this domain presents conformational changes in a non-lipid environment when the mutation D470N is introduced. Using a series of peptides derived from this C-terminal domain, the present study shows that these changes favor the induction of a secondary β-structure as characterized by spectroscopic analysis and fluorescence techniques. From this type of secondary structure, the formation of peptide aggregates and fibrillar structures with amyloid characteristics induced cytotoxicity in microglial cells in culture. These supramolecular structures promote cell cytotoxicity through the formation of reactive oxygen species (ROS) and change the balance of a series of proteins that control the process of endocytosis, similar to that observed when β-amyloid fibrils are employed. Therefore, a fine balance between the highly dynamic secondary structure of the C-terminal domain of CETP, the net charge, and the physicochemical characteristics of the surrounding microenvironment define the type of secondary structure acquired. Changes in this balance might favor misfolding in this region, which would alter the lipid transfer capacity conducted by CETP, favoring its propensity to substitute its physiological function. Full article
(This article belongs to the Special Issue Advances in Molecular Recognition)
Open AccessArticle Cloning, Soluble Expression and Purification of High Yield Recombinant hGMCSF in Escherichia coli
Int. J. Mol. Sci. 2011, 12(3), 2064-2076; doi:10.3390/ijms12032064
Received: 21 January 2011 / Revised: 17 February 2011 / Accepted: 20 March 2011 / Published: 22 March 2011
Cited by 9 | PDF Full-text (374 KB) | HTML Full-text | XML Full-text
Abstract
Expression of human granulocyte macrophage colony stimulating factor (hGMCSF), a cytokine of therapeutic importance, as a thioredoxin (TRX) fusion has been investigated in Escherichia coli BL21 (DE3) codon plus cells. The expression of this protein was low when cloned under the T7 [...] Read more.
Expression of human granulocyte macrophage colony stimulating factor (hGMCSF), a cytokine of therapeutic importance, as a thioredoxin (TRX) fusion has been investigated in Escherichia coli BL21 (DE3) codon plus cells. The expression of this protein was low when cloned under the T7 promoter without any fusion tags. High yield of GMCSF was achieved (~88 mg/L of fermentation broth) in the shake flask when the gene was fused to the E. coli TRX gene. The protein was purified using a single step Ni2+-NTA affinity chromatography and the column bound fusion tag was removed by on-column cleavage with enterokinase. The recombinant hGMCSF was expressed as a soluble and biologically active protein in E. coli, and upon purification, the final yield was ~44 mg/L in shake flask with a specific activity of 2.3 × 108 U/mg. The results of Western blot and RP-HPLC analyses, along with biological activity using the TF-1 cell line, established the identity of the purified hGMCSF. In this paper, we report the highest yield of hGMCSF expressed in E. coli. The bioreactor study shows that the yield of hGMCSF could be easily scalable with a yield of ~400 mg/L, opening up new opportunities for large scale production hGMCSF in E. coli. Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
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Open AccessArticle In Vitro Ability of Currently Available Oximes to Reactivate Organophosphate Pesticide-Inhibited Human Acetylcholinesterase and Butyrylcholinesterase
Int. J. Mol. Sci. 2011, 12(3), 2077-2087; doi:10.3390/ijms12032077
Received: 11 February 2011 / Accepted: 9 March 2011 / Published: 23 March 2011
Cited by 6 | PDF Full-text (185 KB) | HTML Full-text | XML Full-text
Abstract
We have in vitro tested the ability of common, commercially available, cholinesterase reactivators (pralidoxime, obidoxime, methoxime, trimedoxime and HI-6) to reactivate human acetylcholinesterase (AChE), inhibited by five structurally different organophosphate pesticides and inhibitors (paraoxon, dichlorvos, DFP, leptophos-oxon and methamidophos). We also tested [...] Read more.
We have in vitro tested the ability of common, commercially available, cholinesterase reactivators (pralidoxime, obidoxime, methoxime, trimedoxime and HI-6) to reactivate human acetylcholinesterase (AChE), inhibited by five structurally different organophosphate pesticides and inhibitors (paraoxon, dichlorvos, DFP, leptophos-oxon and methamidophos). We also tested reactivation of human butyrylcholinesterase (BChE) with the aim of finding a potent oxime, suitable to serve as a “pseudocatalytic” bioscavenger in combination with this enzyme. Such a combination could allow an increase of prophylactic and therapeutic efficacy of the administered enzyme. According to our results, the best broad-spectrum AChE reactivators were trimedoxime and obidoxime in the case of paraoxon, leptophos-oxon, and methamidophos-inhibited AChE. Methamidophos and leptophos-oxon were quite easily reactivatable by all tested reactivators. In the case of methamidophos-inhibited AChE, the lower oxime concentration (10−5 M) had higher reactivation ability than the 10−4 M concentration. Therefore, we evaluated the reactivation ability of obidoxime in a concentration range of 10−3–10−7 M. The reactivation of methamidophos-inhibited AChE with different obidoxime concentrations resulted in a bell shaped curve with maximum reactivation at 10−5 M. In the case of BChE, no reactivator exceeded 15% reactivation ability and therefore none of the oximes can be recommended as a candidate for “pseudocatalytic” bioscavengers with BChE. Full article
(This article belongs to the Section Molecular Toxicology)
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Review

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Open AccessReview Coupled Folding and Specific Binding: Fishing for Amphiphilicity
Int. J. Mol. Sci. 2011, 12(3), 1431-1450; doi:10.3390/ijms12031431
Received: 25 January 2011 / Revised: 10 February 2011 / Accepted: 17 February 2011 / Published: 24 February 2011
Cited by 5 | PDF Full-text (2679 KB) | HTML Full-text | XML Full-text
Abstract
Proteins are uniquely capable of identifying targets with unparalleled selectivity, but, in addition to the precision of the binding phenomenon, nature has the ability to find its targets exceptionally quickly. Transcription factors for instance can bind to a specific sequence of nucleic [...] Read more.
Proteins are uniquely capable of identifying targets with unparalleled selectivity, but, in addition to the precision of the binding phenomenon, nature has the ability to find its targets exceptionally quickly. Transcription factors for instance can bind to a specific sequence of nucleic acids from a soup of similar, but not identical DNA strands, on a timescale of seconds. This is only possible with the enhanced kinetics provided for by a natively disordered structure, where protein folding and binding are cooperative processes. The secondary structures of many proteins are disordered under physiological conditions. Subsequently, the disordered structures fold into ordered structures only when they bind to their specific targets. Induced folding of the protein has two key biological advantages. First, flexible unstructured domains can result in an intrinsic plasticity that allows them to accommodate targets of various size and shape. And, second, the dynamics of this folding process can result in enhanced binding kinetics. Several groups have hypothesized the acceleration of binding kinetics is due to induced folding where a “fly-casting” effect has been shown to break the diffusion-limited rate of binding. This review describes experimental results in rationally designed peptide systems where the folding is coupled to amphiphilicity and biomolecular activity. Full article
(This article belongs to the Special Issue Advances in Molecular Recognition)
Open AccessReview Integrated Lipidomics in the Secreted Phospholipase A2 Biology
Int. J. Mol. Sci. 2011, 12(3), 1474-1495; doi:10.3390/ijms12031474
Received: 30 January 2011 / Revised: 18 February 2011 / Accepted: 24 February 2011 / Published: 25 February 2011
Cited by 6 | PDF Full-text (764 KB) | HTML Full-text | XML Full-text
Abstract
Mammalian genomes encode genes for more than 30 phospholipase A2s (PLA2s) or related enzymes, which are subdivided into several subgroups based on their structures, catalytic mechanisms, localizations and evolutionary relationships. More than one third of the PLA2 [...] Read more.
Mammalian genomes encode genes for more than 30 phospholipase A2s (PLA2s) or related enzymes, which are subdivided into several subgroups based on their structures, catalytic mechanisms, localizations and evolutionary relationships. More than one third of the PLA2 enzymes belong to the secreted PLA2 (sPLA2) family, which consists of low-molecular-weight, Ca2+-requiring extracellular enzymes, with a His-Asp catalytic dyad. Individual sPLA2 isoforms exhibit unique tissue and cellular localizations and enzymatic properties, suggesting their distinct pathophysiological roles. Recent studies using transgenic and knockout mice for several sPLA2 isoforms, in combination with lipidomics approaches, have revealed their distinct contributions to various biological events. Herein, we will describe several examples of sPLA2-mediated phospholipid metabolism in vivo, as revealed by integrated analysis of sPLA2 transgenic/knockout mice and lipid mass spectrometry. Knowledge obtained from this approach greatly contributes to expanding our understanding of the sPLA2 biology and pathophysiology. Full article
(This article belongs to the Special Issue Phospholipids: Molecular Sciences)
Open AccessReview Mechanisms of Estrogens’ Dose-Dependent Neuroprotective and Neurodamaging Effects in Experimental Models of Cerebral Ischemia
Int. J. Mol. Sci. 2011, 12(3), 1533-1562; doi:10.3390/ijms12031533
Received: 17 August 2010 / Revised: 10 February 2011 / Accepted: 22 February 2011 / Published: 25 February 2011
Cited by 28 | PDF Full-text (446 KB) | HTML Full-text | XML Full-text
Abstract
Ever since the hypothesis was put forward that estrogens could protect against cerebral ischemia, numerous studies have investigated the mechanisms of their effects. Despite initial studies showing ameliorating effects, later trials in both humans and animals have yielded contrasting results regarding the [...] Read more.
Ever since the hypothesis was put forward that estrogens could protect against cerebral ischemia, numerous studies have investigated the mechanisms of their effects. Despite initial studies showing ameliorating effects, later trials in both humans and animals have yielded contrasting results regarding the fundamental issue of whether estrogens are neuroprotective or neurodamaging. Therefore, investigations of the possible mechanisms of estrogen actions in brain ischemia have been difficult to assess. A recently published systematic review from our laboratory indicates that the dichotomy in experimental rat studies may be caused by the use of insufficiently validated estrogen administration methods resulting in serum hormone concentrations far from those intended, and that physiological estrogen concentrations are neuroprotective while supraphysiological concentrations augment the damage from cerebral ischemia. This evidence offers a new perspective on the mechanisms of estrogens’ actions in cerebral ischemia, and also has a direct bearing on the hormone replacement therapy debate. Estrogens affect their target organs by several different pathways and receptors, and the mechanisms proposed for their effects on stroke probably prevail in different concentration ranges. In the current article, previously suggested neuroprotective and neurodamaging mechanisms are reviewed in a hormone concentration perspective in an effort to provide a mechanistic framework for the dose-dependent paradoxical effects of estrogens in stroke. It is concluded that five protective mechanisms, namely decreased apoptosis, growth factor regulation, vascular modulation, indirect antioxidant properties and decreased inflammation, and the proposed damaging mechanism of increased inflammation, are currently supported by experiments performed in optimal biological settings. Full article
(This article belongs to the Special Issue Neuroprotective Strategies (special issue))
Open AccessReview Light-Emitting Devices with Conjugated Polymers
Int. J. Mol. Sci. 2011, 12(3), 1575-1594; doi:10.3390/ijms12031575
Received: 31 December 2010 / Revised: 21 January 2011 / Accepted: 28 January 2011 / Published: 1 March 2011
Cited by 16 | PDF Full-text (389 KB) | HTML Full-text | XML Full-text
Abstract This article introduces a previous study and tremendous progress in basic theoretical modeling, material developments and device engineering for polymer light-emitting devices (PLEDs). Full article
(This article belongs to the Section Material Sciences and Nanotechnology)
Open AccessReview Non-Linear Electrohydrodynamics in Microfluidic Devices
Int. J. Mol. Sci. 2011, 12(3), 1633-1649; doi:10.3390/ijms12031633
Received: 24 January 2011 / Revised: 10 February 2011 / Accepted: 24 February 2011 / Published: 3 March 2011
Cited by 3 | PDF Full-text (658 KB) | HTML Full-text | XML Full-text
Abstract
Since the inception of microfluidics, the electric force has been exploited as one of the leading mechanisms for driving and controlling the movement of the operating fluid and the charged suspensions. Electric force has an intrinsic advantage in miniaturized devices. Because the [...] Read more.
Since the inception of microfluidics, the electric force has been exploited as one of the leading mechanisms for driving and controlling the movement of the operating fluid and the charged suspensions. Electric force has an intrinsic advantage in miniaturized devices. Because the electrodes are placed over a small distance, from sub-millimeter to a few microns, a very high electric field is easy to obtain. The electric force can be highly localized as its strength rapidly decays away from the peak. This makes the electric force an ideal candidate for precise spatial control. The geometry and placement of the electrodes can be used to design electric fields of varying distributions, which can be readily realized by Micro-Electro-Mechanical Systems (MEMS) fabrication methods. In this paper, we examine several electrically driven liquid handling operations. The emphasis is given to non-linear electrohydrodynamic effects. We discuss the theoretical treatment and related numerical methods. Modeling and simulations are used to unveil the associated electrohydrodynamic phenomena. The modeling based investigation is interwoven with examples of microfluidic devices to illustrate the applications. Full article
(This article belongs to the Special Issue Microfluidics)
Open AccessReview The Composition and Organization of Cytoplasm in Prebiotic Cells
Int. J. Mol. Sci. 2011, 12(3), 1650-1659; doi:10.3390/ijms12031650
Received: 26 January 2011 / Revised: 15 February 2011 / Accepted: 23 February 2011 / Published: 3 March 2011
Cited by 9 | PDF Full-text (191 KB) | HTML Full-text | XML Full-text
Abstract
This article discusses the hypothesized composition and organization of cytoplasm in prebiotic cells from a theoretical perspective and also based upon what is currently known about bacterial cytoplasm. It is unknown if the first prebiotic, microscopic scale, cytoplasm was initially contained within [...] Read more.
This article discusses the hypothesized composition and organization of cytoplasm in prebiotic cells from a theoretical perspective and also based upon what is currently known about bacterial cytoplasm. It is unknown if the first prebiotic, microscopic scale, cytoplasm was initially contained within a primitive, continuous, semipermeable membrane, or was an uncontained gel substance, that later became enclosed by a continuous membrane. Another possibility is that the first cytoplasm in prebiotic cells and a primitive membrane organized at the same time, permitting a rapid transition to the first cell(s) capable of growth and division, thus assisting with the emergence of life on Earth less than a billion years after the formation of the Earth. It is hypothesized that the organization and composition of cytoplasm progressed initially from an unstructured, microscopic hydrogel to a more complex cytoplasm, that may have been in the volume magnitude of about 0.1–0.2 µm3 (possibly less if a nanocell) prior to the first cell division. Full article
(This article belongs to the Special Issue Origin of Life 2011)
Open AccessReview The Role of Alpha-Dystrobrevin in Striated Muscle
Int. J. Mol. Sci. 2011, 12(3), 1660-1671; doi:10.3390/ijms12031660
Received: 16 December 2010 / Revised: 29 January 2011 / Accepted: 23 February 2011 / Published: 4 March 2011
Cited by 8 | PDF Full-text (329 KB) | HTML Full-text | XML Full-text
Abstract
Muscular dystrophies are a group of diseases that primarily affect striated muscle and are characterized by the progressive loss of muscle strength and integrity. Major forms of muscular dystrophies are caused by the abnormalities of the dystrophin glycoprotein complex (DGC) that plays [...] Read more.
Muscular dystrophies are a group of diseases that primarily affect striated muscle and are characterized by the progressive loss of muscle strength and integrity. Major forms of muscular dystrophies are caused by the abnormalities of the dystrophin glycoprotein complex (DGC) that plays crucial roles as a structural unit and scaffolds for signaling molecules at the sarcolemma. α-Dystrobrevin is a component of the DGC and directly associates with dystrophin. α-Dystrobrevin also binds to intermediate filaments as well as syntrophin, a modular adaptor protein thought to be involved in signaling. Although no muscular dystrophy has been associated within mutations of the α-dystrobrevin gene, emerging findings suggest potential significance of α-dystrobrevin in striated muscle. This review addresses the functional role of α-dystrobrevin in muscle as well as its possible implication for muscular dystrophy. Full article
(This article belongs to the Special Issue Advances in Muscle Contraction Studies)
Open AccessReview Chitin Scaffolds in Tissue Engineering
Int. J. Mol. Sci. 2011, 12(3), 1876-1887; doi:10.3390/ijms12031876
Received: 15 December 2010 / Revised: 18 February 2011 / Accepted: 11 March 2011 / Published: 15 March 2011
Cited by 42 | PDF Full-text (144 KB) | HTML Full-text | XML Full-text
Abstract
Tissue engineering/regeneration is based on the hypothesis that healthy stem/progenitor cells either recruited or delivered to an injured site, can eventually regenerate lost or damaged tissue. Most of the researchers working in tissue engineering and regenerative technology attempt to create tissue replacements [...] Read more.
Tissue engineering/regeneration is based on the hypothesis that healthy stem/progenitor cells either recruited or delivered to an injured site, can eventually regenerate lost or damaged tissue. Most of the researchers working in tissue engineering and regenerative technology attempt to create tissue replacements by culturing cells onto synthetic porous three-dimensional polymeric scaffolds, which is currently regarded as an ideal approach to enhance functional tissue regeneration by creating and maintaining channels that facilitate progenitor cell migration, proliferation and differentiation. The requirements that must be satisfied by such scaffolds include providing a space with the proper size, shape and porosity for tissue development and permitting cells from the surrounding tissue to migrate into the matrix. Recently, chitin scaffolds have been widely used in tissue engineering due to their non-toxic, biodegradable and biocompatible nature. The advantage of chitin as a tissue engineering biomaterial lies in that it can be easily processed into gel and scaffold forms for a variety of biomedical applications. Moreover, chitin has been shown to enhance some biological activities such as immunological, antibacterial, drug delivery and have been shown to promote better healing at a faster rate and exhibit greater compatibility with humans. This review provides an overview of the current status of tissue engineering/regenerative medicine research using chitin scaffolds for bone, cartilage and wound healing applications. We also outline the key challenges in this field and the most likely directions for future development and we hope that this review will be helpful to the researchers working in the field of tissue engineering and regenerative medicine. Full article
(This article belongs to the Special Issue Chitins)
Open AccessReview Chitin-based Materials in Tissue Engineering: Applications in Soft Tissue and Epithelial Organ
Int. J. Mol. Sci. 2011, 12(3), 1936-1963; doi:10.3390/ijms12031936
Received: 14 February 2011 / Revised: 7 March 2011 / Accepted: 8 March 2011 / Published: 17 March 2011
Cited by 44 | PDF Full-text (399 KB) | HTML Full-text | XML Full-text
Abstract
Chitin-based materials and their derivatives are receiving increased attention in tissue engineering because of their unique and appealing biological properties. In this review, we summarize the biomedical potential of chitin-based materials, specifically focusing on chitosan, in tissue engineering approaches for epithelial and [...] Read more.
Chitin-based materials and their derivatives are receiving increased attention in tissue engineering because of their unique and appealing biological properties. In this review, we summarize the biomedical potential of chitin-based materials, specifically focusing on chitosan, in tissue engineering approaches for epithelial and soft tissues. Both types of tissues play an important role in supporting anatomical structures and physiological functions. Because of the attractive features of chitin-based materials, many characteristics beneficial to tissue regeneration including the preservation of cellular phenotype, binding and enhancement of bioactive factors, control of gene expression, and synthesis and deposition of tissue-specific extracellular matrix are well-regulated by chitin-based scaffolds. These scaffolds can be used in repairing body surface linings, reconstructing tissue structures, regenerating connective tissue, and supporting nerve and vascular growth and connection. The novel use of these scaffolds in promoting the regeneration of various tissues originating from the epithelium and soft tissue demonstrates that these chitin-based materials have versatile properties and functionality and serve as promising substrates for a great number of future applications. Full article
(This article belongs to the Section Material Sciences and Nanotechnology)
Open AccessReview Chaperoning Roles of Macromolecules Interacting with Proteins in Vivo
Int. J. Mol. Sci. 2011, 12(3), 1979-1990; doi:10.3390/ijms12031979
Received: 28 January 2011 / Revised: 15 February 2011 / Accepted: 17 March 2011 / Published: 18 March 2011
Cited by 6 | PDF Full-text (205 KB) | HTML Full-text | XML Full-text
Abstract
The principles obtained from studies on molecular chaperones have provided explanations for the assisted protein folding in vivo. However, the majority of proteins can fold without the assistance of the known molecular chaperones, and little attention has been paid to the [...] Read more.
The principles obtained from studies on molecular chaperones have provided explanations for the assisted protein folding in vivo. However, the majority of proteins can fold without the assistance of the known molecular chaperones, and little attention has been paid to the potential chaperoning roles of other macromolecules. During protein biogenesis and folding, newly synthesized polypeptide chains interact with a variety of macromolecules, including ribosomes, RNAs, cytoskeleton, lipid bilayer, proteolytic system, etc. In general, the hydrophobic interactions between molecular chaperones and their substrates have been widely believed to be mainly responsible for the substrate stabilization against aggregation. Emerging evidence now indicates that other features of macromolecules such as their surface charges, probably resulting in electrostatic repulsions, and steric hindrance, could play a key role in the stabilization of their linked proteins against aggregation. Such stabilizing mechanisms are expected to give new insights into our understanding of the chaperoning functions for de novo protein folding. In this review, we will discuss the possible chaperoning roles of these macromolecules in de novo folding, based on their charge and steric features. Full article
(This article belongs to the Section Molecular Recognition)
Open AccessReview Recent Advances in Conjugated Polymers for Light Emitting Devices
Int. J. Mol. Sci. 2011, 12(3), 2036-2054; doi:10.3390/ijms12032036
Received: 1 February 2011 / Revised: 27 February 2011 / Accepted: 16 March 2011 / Published: 21 March 2011
Cited by 55 | PDF Full-text (372 KB) | HTML Full-text | XML Full-text
Abstract
A recent advance in the field of light emitting polymers has been the discovery of electroluminescent conjugated polymers, that is, kind of fluorescent polymers that emit light when excited by the flow of an electric current. These new generation fluorescent materials may [...] Read more.
A recent advance in the field of light emitting polymers has been the discovery of electroluminescent conjugated polymers, that is, kind of fluorescent polymers that emit light when excited by the flow of an electric current. These new generation fluorescent materials may now challenge the domination by inorganic semiconductor materials of the commercial market in light-emitting devices such as light-emitting diodes (LED) and polymer laser devices. This review provides information on unique properties of conjugated polymers and how they have been optimized to generate these properties. The review is organized in three sections focusing on the major advances in light emitting materials, recent literature survey and understanding the desirable properties as well as modern solid state lighting and displays. Recently, developed conjugated polymers are also functioning as roll-up displays for computers and mobile phones, flexible solar panels for power portable equipment as well as organic light emitting diodes in displays, in which television screens, luminous traffic, information signs, and light-emitting wallpaper in homes are also expected to broaden the use of conjugated polymers as light emitting polymers. The purpose of this review paper is to examine conjugated polymers in light emitting diodes (LEDs) in addition to organic solid state laser. Furthermore, since conjugated polymers have been approved as light-emitting organic materials similar to inorganic semiconductors, it is clear to motivate these organic light-emitting devices (OLEDs) and organic lasers for modern lighting in terms of energy saving ability. In addition, future aspects of conjugated polymers in LEDs were also highlighted in this review. Full article
(This article belongs to the Special Issue Conjugated Polymers)
Open AccessReview Circulating MicroRNAs: Potential Biomarkers for Cancer
Int. J. Mol. Sci. 2011, 12(3), 2055-2063; doi:10.3390/ijms12032055
Received: 21 December 2010 / Revised: 10 February 2011 / Accepted: 10 March 2011 / Published: 22 March 2011
Cited by 35 | PDF Full-text (112 KB) | HTML Full-text | XML Full-text
Abstract
Cancer is the leading cause of death in the world. Development of minimally invasive biomarkers for early detection of cancer is urgently needed to reduce high morbidity and mortality associated with malignancy. MicroRNAs (miRNAs) are small regulatory RNAs that modulate the activity [...] Read more.
Cancer is the leading cause of death in the world. Development of minimally invasive biomarkers for early detection of cancer is urgently needed to reduce high morbidity and mortality associated with malignancy. MicroRNAs (miRNAs) are small regulatory RNAs that modulate the activity of specific mRNA targets and play important roles in a wide range of physiologic and pathologic processes. Recently, miRNAs were found to be dysregulated in a variety of diseases including cancer. Emerging evidence suggests that miRNAs are involved in tumor initiation and progression. Together, the different expression profiles of miRNAs in cancer, and the stability of circulating miRNAs, make them new potentially clinical biomarkers for cancer diagnosis, classification, therapeutic decisions, and prognosis. Full article
(This article belongs to the Special Issue Advances in Molecular Diagnostics)

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