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Int. J. Mol. Sci., Volume 9, Issue 3 (March 2008), Pages 198-433

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Editorial

Jump to: Research, Review

Open AccessEditorial Expression, Characterization and Synergistic Interactions of Myxobacter Sp. AL-1 Cel9 and Cel48 Glycosyl Hydrolases
Int. J. Mol. Sci. 2008, 9(3), 247-257; doi:10.3390/ijms9030247
Received: 2 December 2007 / Revised: 24 January 2008 / Accepted: 1 February 2008 / Published: 29 February 2008
Cited by 7 | PDF Full-text (328 KB) | HTML Full-text | XML Full-text
Abstract
The soil microorganism Myxobacter Sp. AL-1 regulates in a differential manner the production of five extracellular cellulases during its life cycle. The nucleotide sequence of a cel9-cel48 cluster from the genome of this microorganism was recently obtained. Cel48 was expressed in Escherichia coli
[...] Read more.
The soil microorganism Myxobacter Sp. AL-1 regulates in a differential manner the production of five extracellular cellulases during its life cycle. The nucleotide sequence of a cel9-cel48 cluster from the genome of this microorganism was recently obtained. Cel48 was expressed in Escherichia coli to generate a His6-Cel48 protein and the biochemical properties of the pure protein were determined. Cel48 was more efficient in degrading acid-swollen avicel (ASC) than carboxymethylcellulose (CMC). On the other hand, cel9 was expressed in Bacillus subtilis from an IPTG-inducible promoter. Zymogram analysis showed that after IPTG-induction, Cel9 existed in both the cell fraction and the culture medium of B. subtilis and the secreted protein was purified to homogeneity by FPLC-ionic exchange chromatography. The exocellobiohydrolase Cel48 showed a synergism of 1.68 times with the endocellulase Cel9 during ASC degradation using an 8.1- fold excess of Cel48 over Cel9. Western blot analysis revealed that both proteins were synthesized and secreted to the culture medium of Myxobacter Sp. AL-1. These results show that the cel9-cel48 cluster encodes functional endo- and exo-acting cellulases that allows Myobacter Sp. AL-1 to hydrolyse cellulose. Full article
(This article belongs to the Special Issue Biofuels R&D: Securing the Planet's Future Energy Needs)

Research

Jump to: Editorial, Review

Open AccessArticle Biochemical Characterization of the Tetrachlorobenzoquinone Reductase Involved in the Biodegradation of Pentachlorophenol
Int. J. Mol. Sci. 2008, 9(3), 198-212; doi:10.3390/ijms9030198
Received: 16 October 2007 / Revised: 4 January 2007 / Accepted: 15 February 2008 / Published: 27 February 2008
Cited by 10 | PDF Full-text (420 KB) | HTML Full-text | XML Full-text
Abstract
Pentachlorophenol (PCP), a xenobiocide used to preserve lumbers, is a major environmental pollutant in North America. In spite of an expected high resistance to biodegradation, a number of aquatic and soil bacteria can degrade PCP. In this study, we cloned, expressed and purified
[...] Read more.
Pentachlorophenol (PCP), a xenobiocide used to preserve lumbers, is a major environmental pollutant in North America. In spite of an expected high resistance to biodegradation, a number of aquatic and soil bacteria can degrade PCP. In this study, we cloned, expressed and purified tetrachlorobenzoquinone reductase (PcpD), the second enzyme in the PCP biodegradation pathway in Sphingobium chlorophenolicum. PcpD, present mainly as a homo-trimer, exhibited low but statistically significant activity in the reduction of tetrachlorobenzoquinone to tetrachlorohydroquinone. The optimal pH for PcpD activity was 7.0. PcpD was stimulated by tetrachlorohydroquinone at low concentrations but inhibited at high concentrations. Because of the constitutive expression and relatively high catalytic efficiency of downstream enzyme tetrachlorohydroquinone reductive dehalogenase, tetrachlorohydroquinone was unlikely to accumulate in high concentrations, suggesting that PcpD would only be stimulated by tetrachlorohydroquinone under in vivo conditions. It was also shown that PcpD was inhibited by PCP in a concentration-dependent manner. Therefore, PcpD was regulated by tetrachlorohydroquinone and PCP using a possible “Yin-Yang” mechanism, which maintained tetrachlorobeanzoquinone at a level that would neither significantly decrease the biodegradation of PCP nor cause cytotoxicity in S. chlorophenolicum cells. Structural model of PcpD showed that the putative tetrachlorobenzoquinone binding site, adjacent to the cofactor flavin mononucleotide and the 2Fe2S cluster, was situated in a deep pit on the surface and slightly positively charged. Full article
(This article belongs to the Special Issue Interaction of Biological Molecules)
Open AccessArticle PI Polynomial of V-Phenylenic Nanotubes and Nanotori
Int. J. Mol. Sci. 2008, 9(3), 229-234; doi:10.3390/ijms9030229
Received: 22 October 2007 / Revised: 26 November 2007 / Accepted: 4 December 2007 / Published: 28 February 2008
Cited by 6 | PDF Full-text (170 KB) | HTML Full-text | XML Full-text
Abstract
The PI polynomial of a molecular graph is defined to be the sum X|E(G)|−N(e) + |V(G)|(|V(G)|+1)/2 − |E(G)| over all edges of G, where N(e) is the number of edges parallel to e. In this paper, the PI polynomial of the phenylenic
[...] Read more.
The PI polynomial of a molecular graph is defined to be the sum X|E(G)|−N(e) + |V(G)|(|V(G)|+1)/2 − |E(G)| over all edges of G, where N(e) is the number of edges parallel to e. In this paper, the PI polynomial of the phenylenic nanotubes and nanotori are computed. Several open questions are also included. Full article
(This article belongs to the Section Physical Chemistry, Theoretical and Computational Chemistry)
Open AccessArticle 3D-QSAR Investigation of Synthetic Antioxidant Chromone Derivatives by Molecular Field Analysis
Int. J. Mol. Sci. 2008, 9(3), 235-246; doi:10.3390/ijms9030235
Received: 17 September 2007 / Revised: 30 January 2008 / Accepted: 15 February 2008 / Published: 29 February 2008
Cited by 20 | PDF Full-text (390 KB) | HTML Full-text | XML Full-text
Abstract
A series of 7-hydroxy, 8-hydroxy and 7,8-dihydroxy synthetic chromone derivatives was evaluated for their DPPH free radical scavenging activities. A training set of 30 synthetic chromone derivatives was subject to three-dimensional quantitative structure-activity relationship (3D-QSAR) studies using molecular field analysis (MFA). The substitutional
[...] Read more.
A series of 7-hydroxy, 8-hydroxy and 7,8-dihydroxy synthetic chromone derivatives was evaluated for their DPPH free radical scavenging activities. A training set of 30 synthetic chromone derivatives was subject to three-dimensional quantitative structure-activity relationship (3D-QSAR) studies using molecular field analysis (MFA). The substitutional requirements for favorable antioxidant activity were investigated and a predictive model that could be used for the design of novel antioxidants was derived. Regression analysis was carried out using genetic partial least squares (G/PLS) method. A highly predictive and statistically significant model was generated. The predictive ability of the developed model was assessed using a test set of 5 compounds (r2pred = 0.924). The analyzed MFA model demonstrated a good fit, having r2 value of 0.868 and crossvalidated coefficient r2cv value of 0.771. Full article
(This article belongs to the Special Issue Structure-Property/Activity Modeling of Polyphenols)
Open AccessArticle Closing in on Chemical Bonds by Opening up Relativity Theory
Int. J. Mol. Sci. 2008, 9(3), 272-298; doi:10.3390/ijms9030272
Received: 4 December 2007 / Revised: 15 February 2008 / Accepted: 26 February 2008 / Published: 12 March 2008
Cited by 5 | PDF Full-text (904 KB) | HTML Full-text | XML Full-text
Abstract
This paper develops a connection between the phenomenology of chemical bonding and the theory of relativity. Empirical correlations between electron numbers in atoms and chemical bond stabilities in molecules are first reviewed and extended. Quantitative chemical bond strengths are then related to ionization
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This paper develops a connection between the phenomenology of chemical bonding and the theory of relativity. Empirical correlations between electron numbers in atoms and chemical bond stabilities in molecules are first reviewed and extended. Quantitative chemical bond strengths are then related to ionization potentials in elements. Striking patterns in ionization potentials are revealed when the data are viewed in an element-independent way, where element-specific details are removed via an appropriate scaling law. The scale factor involved is not explained by quantum mechanics; it is revealed only when one goes back further, to the development of Einstein’s special relativity theory. Full article
(This article belongs to the Special Issue The Chemical Bond and Bonding)
Open AccessArticle RNA Interference in Mammalia Cells by RNA-3’-PNA Chimeras
Int. J. Mol. Sci. 2008, 9(3), 299-315; doi:10.3390/ijms9030299
Received: 13 December 2007 / Revised: 29 February 2008 / Accepted: 29 February 2008 / Published: 12 March 2008
Cited by 26 | PDF Full-text (276 KB) | HTML Full-text | XML Full-text
Abstract
The discovery of siRNAs as the mediators of RNA interference has led to an increasing interest in their therapeutic applications. Chemical modifications are introduced into siRNAs to optimize the potency, the stability and the pharmacokinetic properties in vivo. Here, we synthesize and test
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The discovery of siRNAs as the mediators of RNA interference has led to an increasing interest in their therapeutic applications. Chemical modifications are introduced into siRNAs to optimize the potency, the stability and the pharmacokinetic properties in vivo. Here, we synthesize and test the effects of RNA-3’-PNA chimeras on siRNA functioning and stability. We demonstrate that the chemical modifications are compatible with the siRNA machinery, because all the PNA-modified siRNAs can efficiently mediate specific gene silencing in mammalian cells. Furthermore, we find that the modification on the sense strand of siRNA results in an increased persistence of the activity, whereas modification on both strands results in enhanced nuclease resistance in serum. Full article
(This article belongs to the Special Issue Nucleic Acid Derivatives in Emerging Technologies)
Open AccessArticle Voltammetric Behavior of o-Nitrophenol and Damage to DNA
Int. J. Mol. Sci. 2008, 9(3), 316-326; doi:10.3390/ijms9030316
Received: 3 December 2007 / Revised: 15 February 2008 / Accepted: 29 February 2008 / Published: 12 March 2008
Cited by 8 | PDF Full-text (360 KB) | HTML Full-text | XML Full-text
Abstract
The electrochemical behavior of o-nitrophenol was studied in detail with a glassy carbon electrode (GCE). The dependence of peak potential on pH indicated that equivalent electrons and protons were involved in the process of o-nitrophenol reduction. The interaction of o-nitrophenol with calf thymus
[...] Read more.
The electrochemical behavior of o-nitrophenol was studied in detail with a glassy carbon electrode (GCE). The dependence of peak potential on pH indicated that equivalent electrons and protons were involved in the process of o-nitrophenol reduction. The interaction of o-nitrophenol with calf thymus DNA was investigated by adding DNA to the o-nitrophenol solution and by immobilizing DNA on GCE, respectively. The peak current decrement and peak potential shift in presence of DNA indicated that o-nitrophenol could interact with DNA. The result was demonstrated that the in situ DNA damage was detected by differential pulse voltammetry after the o-nitrophenol was electrochemically reduced. Full article
(This article belongs to the Special Issue Nucleic Acid Derivatives in Emerging Technologies)
Open AccessArticle Dietary Berries and Ellagic Acid Prevent Oxidative DNA Damage and Modulate Expression of DNA Repair Genes
Int. J. Mol. Sci. 2008, 9(3), 327-341; doi:10.3390/ijms9030327
Received: 17 January 2008 / Accepted: 1 February 2008 / Published: 12 March 2008
Cited by 39 | PDF Full-text (1346 KB) | HTML Full-text | XML Full-text
Abstract
DNA damage is a pre-requisite for the initiation of cancer and agents that reduce this damage are useful in cancer prevention. In this study, we evaluated the ability of whole berries and berry phytochemical, ellagic acid to reduce endogenous oxidative DNA damage. Ellagic
[...] Read more.
DNA damage is a pre-requisite for the initiation of cancer and agents that reduce this damage are useful in cancer prevention. In this study, we evaluated the ability of whole berries and berry phytochemical, ellagic acid to reduce endogenous oxidative DNA damage. Ellagic acid was selected based on >95% inhibition of 8-oxodeoxyguosine (8-oxodG) and other unidentified oxidative DNA adducts induced by 4-hydroxy-17ß-estradiol and CuCl2 in vitro. Inhibition of the latter occurred at lower concentrations (10 μM) than that for 8-oxodG (100 μM). In the in vivo study, female CD-1 mice (n=6) were fed either a control diet or diet supplemented with ellagic acid (400 ppm) and dehydrated berries (5% w/w) with varying ellagic acid contents – blueberry (low), strawberry (medium) and red raspberry (high), for 3 weeks. Blueberry and strawberry diets showed moderate reductions in endogenous DNA adducts (25%). However, both red raspberry and ellagic acid diets showed a significant reduction of 59% (p <0.001) and 48% (p < 0.01), respectively. Both diets also resulted in a 3-8 fold over-expression of genes involved in DNA repair such as xeroderma pigmentosum group A complementing protein (XPA), DNA excision repair protein (ERCC5) and DNA ligase III (DNL3). These results suggest that red raspberry and ellagic acid reduce endogenous oxidative DNA damage by mechanisms which may involve increase in DNA repair. Full article
(This article belongs to the Special Issue Natural Compounds for Cancer Treatment and Prevention)
Open AccessArticle Synthesis and Characterization of Core-Shell Acrylate Based Latex and Study of Its Reactive Blends
Int. J. Mol. Sci. 2008, 9(3), 342-354; doi:10.3390/ijms9030342
Received: 18 December 2007 / Revised: 17 February 2008 / Accepted: 3 March 2008 / Published: 12 March 2008
Cited by 15 | PDF Full-text (260 KB) | HTML Full-text | XML Full-text
Abstract
Techniques in resin blending are simple and efficient method for improving the properties of polymers, and have been used widely in polymer modification field. However, polymer latex blends such as the combination of latexes, especially the latexes with water-soluble polymers, were rarely reported.
[...] Read more.
Techniques in resin blending are simple and efficient method for improving the properties of polymers, and have been used widely in polymer modification field. However, polymer latex blends such as the combination of latexes, especially the latexes with water-soluble polymers, were rarely reported. Here, we report a core-shell composite latex synthesized using methyl methacrylate (MMA), butyl acrylate (BA), 2-ethylhexyl acrylate (EHA) and glycidyl methacrylate (GMA) as monomers and ammonium persulfate and sodium bisulfite redox system as the initiator. Two stages seeded semi-continuous emulsion polymerization were employed for constructing a core-shell structure with P(MMA-co-BA) component as the core and P(EHA-co-GMA) component as the shell. Results of Transmission Electron Microscopy (TEM) and Dynamics Light Scattering (DLS) tests confirmed that the particles obtained are indeed possessing a desired core-shell structural character. Stable reactive latex blends were prepared by adding the latex with waterborne melamine-formaldehyde resin (MF) or urea-formaldehyde resin (UF). It was found that the glass transition temperature, the mechanical strength and the hygroscopic property of films cast from the latex blends present marked enhancements under higher thermal treatment temperature. It was revealed that the physical properties of chemically reactive latexes with core-shell structure could be altered via the change of crosslinking density both from the addition of crosslinkers and the thermal treatment. Full article
(This article belongs to the Special Issue Green Antifouling)
Open AccessArticle Fusarium Graminearum Growth Inhibition Due to Glucose Starvation Caused by Osthol
Int. J. Mol. Sci. 2008, 9(3), 371-382; doi:10.3390/ijms9030371
Received: 13 September 2007 / Revised: 28 February 2008 / Accepted: 12 March 2008 / Published: 14 March 2008
Cited by 2 | PDF Full-text (971 KB) | HTML Full-text | XML Full-text
Abstract
The effects of osthol, a plant coumarin, on morphology, sugar uptake and cell wall components of Fusarium graminearum were examined in vitro by electron microscopy, 14C-labelling and enzyme activity detection. The results revealed that osthol could inhibit the hypha growth of F.
[...] Read more.
The effects of osthol, a plant coumarin, on morphology, sugar uptake and cell wall components of Fusarium graminearum were examined in vitro by electron microscopy, 14C-labelling and enzyme activity detection. The results revealed that osthol could inhibit the hypha growth of F. graminearum by decreasing hyphal absorption to reducing sugar. After treatment with 100 μg·mL-1 osthol for 24 h, many hyphal fragments of F. graminearum appeared. Microscopy observation showed that the cell walls of hyphal fragments blurred and the organelles of the cells degraded with the increasing vacuoles. The N-acetyl-D-glucosamine contents and chitinase activity both increased when hypha were treated with 100 μg·mL-1 osthol, whereas the activity of β-1,6-glucanase remained unchanged. When F. graminearum fed with 14C glucose was treated with 100 μg·mL-1osthol, glucose contents decreased to the lowest level, while the contents in non-osthol treated controls remained unchanged. These results suggested that chitinase activity might be related to glucose starvation under osthol treatment, and that the appearance of hyphae fragments maybe the results of the promoted chitinase activity which itself triggered chitin degradation. Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
Open AccessArticle Synthesis and Characterization of Polyacetylene with Side-chain Thiophene Functionality
Int. J. Mol. Sci. 2008, 9(3), 383-393; doi:10.3390/ijms9030383
Received: 30 November 2007 / Revised: 30 January 2008 / Accepted: 29 February 2008 / Published: 18 March 2008
Cited by 10 | PDF Full-text (603 KB) | HTML Full-text | XML Full-text
Abstract
A new polyacetylene derivative with electroactive thiophene substituent, namely poly(2-methylbut-2-enyl thiophene-3-carboxylate) was synthesized and characterized. For this purpose, novel acetylene monomer was synthesized by the reaction of 3- thiophenecarboxylic acid with propargyl bromide and polymerized with a Rh catalyst to give the corresponding
[...] Read more.
A new polyacetylene derivative with electroactive thiophene substituent, namely poly(2-methylbut-2-enyl thiophene-3-carboxylate) was synthesized and characterized. For this purpose, novel acetylene monomer was synthesized by the reaction of 3- thiophenecarboxylic acid with propargyl bromide and polymerized with a Rh catalyst to give the corresponding polymer. The chemical structure of the polymer was characterized to comprise the conjugated backbone and electroactive thiophene side group. UV spectral changes of the polymer with temperature were also studied. The polymer exhibited better thermal stability than the unsubstituted polyacetylenes. Full article
Open AccessArticle Interaction of Wild Strains of Aspergilla with Aspergillus parasiticus ATCC15517 on Aflatoxins Production
Int. J. Mol. Sci. 2008, 9(3), 394-400; doi:10.3390/ijms9030394
Received: 11 January 2008 / Revised: 18 February 2008 / Accepted: 18 March 2008 / Published: 20 March 2008
Cited by 7 | PDF Full-text (95 KB) | HTML Full-text | XML Full-text
Abstract
Aflatoxins are secondary metabolites produced by some competent mould strains of Aspergillus flavus, A. parasiticus and A. nomius. These compounds have been extensively studied concerning its toxicity for animals and humans; they are able to induce liver cancer and caused a large range
[...] Read more.
Aflatoxins are secondary metabolites produced by some competent mould strains of Aspergillus flavus, A. parasiticus and A. nomius. These compounds have been extensively studied concerning its toxicity for animals and humans; they are able to induce liver cancer and caused a large range of adverse effects on living organisms. Aflatoxins are found as natural contaminants of food and feed; the main line of the strategy to control them is based on the prevention of the mould growth in raw vegetable or during its storage and monitoring of each crop batch. Moulds growth is conditioned by many ecological factors, including biotic one’s. Hazard characterization models for Aflatoxins in crops must take in consideration the biotic interaction that moulds establish between them on their growth development. The aim of this work is to study the effect of the biotic interaction of 14 different wild strains of Aspergilla (different species), with a competent strain (Aspergillus parasiticus ATCC 15517) using an in vitro production model. The laboratorial model concerns to a natural matrix (humidified cracked corn), in which each wild strain challenged the producer strain for Aflatoxins production. Cultures were incubated at 28ºC for 12 days and sampled at 8th and 12th. Aflatoxins detection and quantification was performed by HPLC using a procedure with a MRPL = 1 μg/kg. Results of those interactive cultures revealed both synergic and antagonist effects on the Aflatoxin biosynthesis. Productivity increases were particularly evident at 8th day of incubation with wild strains of A. flavipes (+ 70.4 % ), A. versicolor (+ 54.9 %) and A. flavus 3 (+ 62.6 %). Antagonist effects were found with A. niger (- 69.5%) , A. fumigatus (- 47.6 %) and A. terreus (- 47.6 %) at 12th day. The increasable effects were more evident at 8th of incubation and the decrease was more patent at the 12th day. Results show that the development of Aspergilla strains concomitantly with competent aflatoxins producer moulds has a significant influence on the natural biosynthesis pattern. Full article
Open AccessArticle Effect of Locked-Nucleic Acid on a Biologically Active G-Quadruplex. A Structure-Activity Relationship of the Thrombin Aptamer
Int. J. Mol. Sci. 2008, 9(3), 422-433; doi:10.3390/ijms9030422
Received: 23 January 2008 / Revised: 17 March 2008 / Accepted: 18 March 2008 / Published: 24 March 2008
Cited by 48 | PDF Full-text (270 KB) | HTML Full-text | XML Full-text
Abstract
Here we tested the ability to augment the biological activity of the thrombin aptamer, d(GGTTGGTGTGGTTGG), by using locked nucleic acid (LNA) to influence its G-quadruplex structure. Compared to un-substituted control aptamer, LNA-containing aptamers displayed varying degrees of thrombin inhibition. Aptamers with LNA substituted
[...] Read more.
Here we tested the ability to augment the biological activity of the thrombin aptamer, d(GGTTGGTGTGGTTGG), by using locked nucleic acid (LNA) to influence its G-quadruplex structure. Compared to un-substituted control aptamer, LNA-containing aptamers displayed varying degrees of thrombin inhibition. Aptamers with LNA substituted in either positions G5, T7, or G8 showed decreased thrombin inhibition, whereas LNA at position G2 displayed activity comparable to un-substituted control aptamer. Interestingly, the thermal stability of the substituted aptamers does not correlate to activity – the more stable aptamers with LNA in position G5, T7, or G8 showed the least thrombin inhibition, while a less stable aptamer with LNA at G2 was as active as the un-substituted aptamer. These results suggest that LNA substitution at sites G5, T7, and G8 directly perturbs aptamer-thrombin affinity. This further implies that for the thrombin aptamer, activity is not dictated solely by the stability of the G-quadruplex structure, but by specific interactions between the central TGT loop and thrombin and that LNA can be tolerated in a biologically active nucleic acid structure albeit in a position dependent fashion. Full article
(This article belongs to the Special Issue Nucleic Acid Derivatives in Emerging Technologies)

Review

Jump to: Editorial, Research

Open AccessReview Modulatory Effects of Polyphenols on Apoptosis Induction: Relevance for Cancer Prevention
Int. J. Mol. Sci. 2008, 9(3), 213-228; doi:10.3390/ijms9030213
Received: 3 August 2007 / Revised: 30 November 2007 / Accepted: 23 January 2008 / Published: 28 February 2008
Cited by 70 | PDF Full-text (425 KB) | HTML Full-text | XML Full-text
Abstract
Polyphenols, occurring in fruit and vegetables, wine, tea, extra virgin olive oil, chocolate and other cocoa products, have been demonstrated to have clear antioxidant properties in vitro, and many of their biological actions have been attributed to their intrinsic reducing capabilities. However,
[...] Read more.
Polyphenols, occurring in fruit and vegetables, wine, tea, extra virgin olive oil, chocolate and other cocoa products, have been demonstrated to have clear antioxidant properties in vitro, and many of their biological actions have been attributed to their intrinsic reducing capabilities. However, it has become clear that, in complex biological systems, polyphenols exhibit several additional properties which are yet poorly understood. Apoptosis is a genetically controlled and evolutionarily conserved form of cell death of critical importance for the normal embryonic development and for the maintenance of tissue homeostasis in the adult organism. The malfunction of the death machinery may play a primary role in various pathological processes, since too little or too much apoptosis can lead to proliferative or degenerative diseases, respectively. Cancer cells are characterized by a deregulated proliferation, and/or an inability to undergo programmed cell death. A large body of evidence indicates that polyphenols can exert chemopreventive effects towards different organ specific cancers, affecting the overall process of carcinogenesis by several mechanisms: inhibition of DNA synthesis, modulation of ROS production, regulation of cell cycle arrest, modulation of survival/proliferation pathways. In addition, polyphenols can directly influence different points of the apoptotic process, and/or the expression of Int. J. Mol. Sci. 2008, 9 214 regulatory proteins. Although the bulk of data has been obtained in in vitro systems, a number of clinical studies suggesting a preventive and therapeutic effectiveness of polyphenols in vivo is available. However, a deeper knowledge of the underlying mechanisms responsible for the modulation of apoptosis by polyphenols, and their real effectiveness, is necessary in order to propose them as potential chemopreventive and chemotherapeutic candidates for cancer treatment. Full article
(This article belongs to the Special Issue Natural Compounds for Cancer Treatment and Prevention)
Open AccessReview Selenium Derivatization of Nucleic Acids for Phase and Structure Determination in Nucleic Acid X-ray Crystallography
Int. J. Mol. Sci. 2008, 9(3), 258-271; doi:10.3390/ijms9030258
Received: 3 December 2007 / Revised: 18 February 2008 / Accepted: 25 February 2008 / Published: 12 March 2008
Cited by 24 | PDF Full-text (304 KB) | HTML Full-text | XML Full-text
Abstract
Selenium derivatization (via selenomethionine) of proteins for crystal structure determination via MAD phasing has revolutionized protein X-ray crystallography. It is estimated that over two thirds of all new crystal structures of proteins have been determined via Se-Met derivatization. Similarly, selenium functionalities have also
[...] Read more.
Selenium derivatization (via selenomethionine) of proteins for crystal structure determination via MAD phasing has revolutionized protein X-ray crystallography. It is estimated that over two thirds of all new crystal structures of proteins have been determined via Se-Met derivatization. Similarly, selenium functionalities have also been successfully incorporated into nucleic acids to facilitate their structure studies and it has been proved that this Se-derivatization has advantages over halogen strategy, which was usually used as a traditional method in this field. This review reports the development of site-specific selenium derivatization of nucleic acids for phase determination since the year of 2001 (mainly focus on the 2’-position of the ribose). All the synthesis of 2’-SeMe modified phosphoramidite building blocks (U, C, T, A, G) and the according oligonucleotides are included. In addition, several structures of selenium contained nucleic acid are also described in this paper. Full article
(This article belongs to the Special Issue Nucleic Acid Derivatives in Emerging Technologies)
Open AccessReview Anti-Cancer Effects of Xanthones from Pericarps of Mangosteen
Int. J. Mol. Sci. 2008, 9(3), 355-370; doi:10.3390/ijms9030355
Received: 10 January 2008 / Revised: 13 February 2008 / Accepted: 15 February 2008 / Published: 14 March 2008
Cited by 117 | PDF Full-text (1144 KB) | HTML Full-text | XML Full-text
Abstract
Mangosteen, Garcinia mangostana Linn, is a tree found in South East Asia, and its pericarps have been used as traditional medicine. Phytochemical studies have shown that they contain a variety of secondary metabolites, such as oxygenated and prenylated xanthones. Recent studies revealed that
[...] Read more.
Mangosteen, Garcinia mangostana Linn, is a tree found in South East Asia, and its pericarps have been used as traditional medicine. Phytochemical studies have shown that they contain a variety of secondary metabolites, such as oxygenated and prenylated xanthones. Recent studies revealed that these xanthones exhibited a variety of biological activities containing anti-inflammatory, anti-bacterial, and anti-cancer effects. We previously investigated the anti-proliferative effects of four prenylated xanthones from the pericarps; α-mangostin, β-mangostin, γ-mangostin, and methoxy-β-mangostin in various human cancer cells. These xanthones are different in the number of hydroxyl and methoxy groups. Except for methoxy-β-mangostin, the other three xanthones strongly inhibited cell growth at low concentrations from 5 to 20 μM in human colon cancer DLD-1 cells. Our recent study focused on the mechanism of α-mangostin-induced growth inhibition in DLD-1 cells. It was shown that the anti-proliferative effects of the xanthones were associated with cell-cycle arrest by affecting the expression of cyclins, cdc2, and p27; G1 arrest by α- mangostin and β-mangostin, and S arrest by γ-mangostin. α-Mangostin found to induce apoptosis through the activation of intrinsic pathway following the down-regulation of signaling cascades involving MAP kinases and the serine/threonine kinase Akt. Synergistic effects by the combined treatment of α-mangostin and anti-cancer drug 5-FU was to be noted. α-Mangostin was found to have a cancer preventive effect in rat carcinogenesis bioassay and the extract from pericarps, which contains mainly α-mangostin and γ- mangostin, exhibited an enhancement of NK cell activity in a mouse model. These findings could provide a relevant basis for the development of xanthones as an agent for cancer prevention and the combination therapy with anti-cancer drugs. Full article
(This article belongs to the Special Issue Natural Compounds for Cancer Treatment and Prevention)
Open AccessReview Synthetic Efforts for Stereo Structure Determination of Cytotoxic Marine Natural Product Pericosines as Metabolites of Periconia sp. from Sea Hare
Int. J. Mol. Sci. 2008, 9(3), 401-421; doi:10.3390/ijms9030401
Received: 10 January 2008 / Revised: 18 March 2008 / Accepted: 19 March 2008 / Published: 24 March 2008
Cited by 21 | PDF Full-text (423 KB) | HTML Full-text | XML Full-text
Abstract
Pericosines are unique C7 cyclohexenoid metabolites of Periconia byssoides OUPS-N133 fungus that was originally isolated from the sea hare, Aplysia kurodai. Pericosines show significant in vitro cytotoxicity against P388 lymphocytic leukemia cells. Pericosine A, in particular, shows the most potent activity and
[...] Read more.
Pericosines are unique C7 cyclohexenoid metabolites of Periconia byssoides OUPS-N133 fungus that was originally isolated from the sea hare, Aplysia kurodai. Pericosines show significant in vitro cytotoxicity against P388 lymphocytic leukemia cells. Pericosine A, in particular, shows the most potent activity and significant in vivo antitumor activity against P388 cells. Thus, pericosines are promising candidates for seed compounds of anticancer drugs. However, before the total syntheses of pericosines were accomplished, their stereo structures could not be determined by spectral analyses because they have multifunctionalized cyclohexenoid structures with torsional strain. In this review, synthetic efforts for pericosines in this decade are surveyed. Full article
(This article belongs to the Special Issue Natural Compounds for Cancer Treatment and Prevention)

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