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Int. J. Mol. Sci., Volume 10, Issue 8 (August 2009) – 22 articles , Pages 3269-3670

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130 KiB  
Article
Co-Expression of Neighboring Genes in the Zebrafish (Danio rerio) Genome
by Huai-Kuang Tsai, Pei-Ying Huang, Cheng-Yan Kao and Daryi Wang
Int. J. Mol. Sci. 2009, 10(8), 3658-3670; https://doi.org/10.3390/ijms10083658 - 21 Aug 2009
Cited by 13 | Viewed by 11385
Abstract
Neighboring genes in the eukaryotic genome have a tendency to express concurrently, and the proximity of two adjacent genes is often considered a possible explanation for their co-expression behavior. However, the actual contribution of the physical distance between two genes to their co-expression [...] Read more.
Neighboring genes in the eukaryotic genome have a tendency to express concurrently, and the proximity of two adjacent genes is often considered a possible explanation for their co-expression behavior. However, the actual contribution of the physical distance between two genes to their co-expression behavior has yet to be defined. To further investigate this issue, we studied the co-expression of neighboring genes in zebrafish, which has a compact genome and has experienced a whole genome duplication event. Our analysis shows that the proportion of highly co-expressed neighboring pairs (Pearson’s correlation coefficient R>0.7) is low (0.24% ~ 0.67%); however, it is still significantly higher than that of random pairs. In particular, the statistical result implies that the co-expression tendency of neighboring pairs is negatively correlated with their physical distance. Our findings therefore suggest that physical distance may play an important role in the co-expression of neighboring genes. Possible mechanisms related to the neighboring genes’ co-expression are also discussed. Full article
(This article belongs to the Section Physical Chemistry, Theoretical and Computational Chemistry)
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85 KiB  
Editorial
Molecular System Bioenergetics—New Aspects of Metabolic Research
by Valdur Saks
Int. J. Mol. Sci. 2009, 10(8), 3655-3657; https://doi.org/10.3390/ijms10083655 - 19 Aug 2009
Cited by 1 | Viewed by 11318
Abstract
This Special Issue is a significant step in developing a new direction of metabolic research— Molecular System Bioenergetics, which itself is a part of Systems Biology. As a new paradigm of biological sciences, Systems Biology aims at understanding of biological functions by studies [...] Read more.
This Special Issue is a significant step in developing a new direction of metabolic research— Molecular System Bioenergetics, which itself is a part of Systems Biology. As a new paradigm of biological sciences, Systems Biology aims at understanding of biological functions by studies and description of new, system level properties, resulting from interactions between components of biological systems at any level of organization, from molecular to population. Metabolism is the way of life of cells by exchanging mass and energy with the surrounding medium, and understanding its mechanisms requires knowledge of the complex interactions between cellular systems and components. While studies of metabolism have a long history, new concepts of Systems Biology provide useful tools for metabolic research. According to Schrödinger, living cells need to be open systems with energy and mass exchange with the surrounding medium, with the aim of maintaining their high structural and functional organization and thus their internal entropy low, achieving this by means of increasing the entropy of the medium by catabolic reactions. Thus, Schrödinger wrote: “The essential thing in metabolism is that the organism succeeds in freeing itself from all entropy it cannot help producing while alive”. Thus, free energy conversion in the cells is an important, central part of metabolism, and understanding the complex mechanisms of its regulation is the aim of Molecular System Bioenergetics. In this Special Issue, several important problems in this field were analyzed. Full article
(This article belongs to the Special Issue Molecular System Bioenergetics)
604 KiB  
Review
Biodegradability Evaluation of Polymers by ISO 14855-2
by Masahiro Funabashi, Fumi Ninomiya and Masao Kunioka
Int. J. Mol. Sci. 2009, 10(8), 3635-3654; https://doi.org/10.3390/ijms10083635 - 18 Aug 2009
Cited by 78 | Viewed by 19032
Abstract
Biodegradabilities of polymers and their composites in a controlled compost were described. Polycaprolactone (PCL) and poly(lactic acid) (PLA) were employed as biodegradable polymers. Biodegradabilities of PCL and PLA samples in a controlled compost were measured using a Microbial Oxidative Degradation Analyzer (MODA) according [...] Read more.
Biodegradabilities of polymers and their composites in a controlled compost were described. Polycaprolactone (PCL) and poly(lactic acid) (PLA) were employed as biodegradable polymers. Biodegradabilities of PCL and PLA samples in a controlled compost were measured using a Microbial Oxidative Degradation Analyzer (MODA) according to ISO 14855-2. Sample preparation method for biodegradation test according to ISO/DIS 10210 was also described. Effects of sizes and shapes of samples on biodegradability were studied. Reproducibility of biodegradation test of ISO 14855-2 by MODA was confirmed. Validity of sample preparation method for polymer pellets, polymer film, and polymer products of ISO/DIS 10210 for ISO 14855-2 was confirmed. Full article
(This article belongs to the Special Issue Biodegradability of Materials)
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361 KiB  
Article
Effect of the Polysaccharide Extract from the Edible Mushroom Pleurotus ostreatus against Infectious Bursal Disease Virus
by Mircea Selegean, Mihai V. Putz and Tatiana Rugea
Int. J. Mol. Sci. 2009, 10(8), 3616-3634; https://doi.org/10.3390/ijms10083616 - 18 Aug 2009
Cited by 36 | Viewed by 11930
Abstract
The polysaccharide-containing extracellular fractions (EFs) of the edible mushroom Pleurotus ostreatus have immunomodulating effects. Being aware of these therapeutic effects of mushroom extracts, we have investigated the synergistic relations between these extracts and BIAVAC and BIAROMVAC vaccines. These vaccines target the stimulation of [...] Read more.
The polysaccharide-containing extracellular fractions (EFs) of the edible mushroom Pleurotus ostreatus have immunomodulating effects. Being aware of these therapeutic effects of mushroom extracts, we have investigated the synergistic relations between these extracts and BIAVAC and BIAROMVAC vaccines. These vaccines target the stimulation of the immune system in commercial poultry, which are extremely vulnerable in the first days of their lives. By administrating EF with polysaccharides from P. ostreatus to unvaccinated broilers we have noticed slow stimulation of maternal antibodies against infectious bursal disease (IBD) starting from four weeks post hatching. For the broilers vaccinated with BIAVAC and BIAROMVAC vaccines a low to almost complete lack of IBD maternal antibodies has been recorded. By adding 5% and 15% EF in the water intake, as compared to the reaction of the immune system in the previous experiment, the level of IBD antibodies was increased. This has led us to believe that by using this combination of BIAVAC and BIAROMVAC vaccine and EF from P. ostreatus we can obtain good results in stimulating the production of IBD antibodies in the period of the chicken first days of life, which are critical to broilers’ survival. This can be rationalized by the newly proposed reactivity biological activity (ReBiAc) principles by examining the parabolic relationship between EF administration and recorded biological activity. Full article
(This article belongs to the Section Biochemistry)
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972 KiB  
Article
Utilization of a Biodegradable Mulch Sheet Produced from Poly(Lactic Acid)/Ecoflex®/Modified Starch in Mandarin Orange Groves
by Yuya Tachibana, Takuya Maeda, Osamu Ito, Yasukatsu Maeda and Masao Kunioka
Int. J. Mol. Sci. 2009, 10(8), 3599-3615; https://doi.org/10.3390/ijms10083599 - 17 Aug 2009
Cited by 24 | Viewed by 14032
Abstract
We have developed a mulch sheet made by inflation molding of PLA, Ecoflex® and modified starch, which all have different biodegradabilities. A field test of use as an agricultural mulch sheet for mandarin oranges was carried out over two years. The mechanical properties [...] Read more.
We have developed a mulch sheet made by inflation molding of PLA, Ecoflex® and modified starch, which all have different biodegradabilities. A field test of use as an agricultural mulch sheet for mandarin oranges was carried out over two years. The mechanical properties of the mulch sheet were weakened with time during the field test, but the quality of the mandarin oranges increased, a result of the controlled degradation of the sheet. The most degradable modified starch degraded first, allowing control of the moisture on the soil. Accelerator mass spectroscopy was used for evaluation of the biomass carbon ratio. The biomass carbon ratio decreased by degradation of the biobased materials, PLA and modified starch in the mulch sheet. Full article
(This article belongs to the Special Issue Biodegradability of Materials)
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379 KiB  
Article
Effect of Potato Virus Y on the NADP-Malic Enzyme from Nicotiana tabacum L.: mRNA, Expressed Protein and Activity
by Veronika Doubnerová, Karel Müller, Noemi Čeřovská, Helena Synková, Petra Spoustová and Helena Ryšlavá
Int. J. Mol. Sci. 2009, 10(8), 3583-3598; https://doi.org/10.3390/ijms10083583 - 13 Aug 2009
Cited by 17 | Viewed by 14520
Abstract
The effect of biotic stress induced by viral infection (Potato virus Y, strain NTN and O) on NADP-malic enzyme (EC 1.1.1.40) in tobacco plants (Nicotiana tabacum L., cv. Petit Havana, SR1) was tested at the transcriptional, translational and activity level. [...] Read more.
The effect of biotic stress induced by viral infection (Potato virus Y, strain NTN and O) on NADP-malic enzyme (EC 1.1.1.40) in tobacco plants (Nicotiana tabacum L., cv. Petit Havana, SR1) was tested at the transcriptional, translational and activity level. The increase of enzyme activity in infected leaves was correlated with the increased amount of expressed protein and with mRNA of cytosolic NADP-ME isoform. Transcription of the chloroplastic enzyme was not influenced by viral infection. The increase of the enzyme activity was also detected in stems and roots of infected plants. The effect of viral infection induced by Potato virus Y, NTN strain, causing more severe symptoms, was compared with the effect induced by milder strain PVYO. The observed increase in NADP-malic enzyme activity in all parts of the studied plants was higher in the case of PVYNTN strain than in the case of strain PVYO. The relevance of NADP-malic enzyme in plants under stress conditions was discussed. Full article
(This article belongs to the Special Issue Biotic and Abiotic Stress)
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335 KiB  
Review
A Focus on Natural Variation for Abiotic Constraints Response in the Model Species Arabidopsis thaliana
by Valérie Lefebvre, Seifollah Poormohammad Kiani and Mylène Durand-Tardif
Int. J. Mol. Sci. 2009, 10(8), 3547-3582; https://doi.org/10.3390/ijms10083547 - 13 Aug 2009
Cited by 30 | Viewed by 21286
Abstract
Plants are particularly subject to environmental stress, as they cannot move from unfavourable surroundings. As a consequence they have to react in situ. In any case, plants have to sense the stress, then the signal has to be transduced to engage the [...] Read more.
Plants are particularly subject to environmental stress, as they cannot move from unfavourable surroundings. As a consequence they have to react in situ. In any case, plants have to sense the stress, then the signal has to be transduced to engage the appropriate response. Stress response is effected by regulating genes, by turning on molecular mechanisms to protect the whole organism and its components and/or to repair damage. Reactions vary depending on the type of stress and its intensity, but some are commonly turned on because some responses to different abiotic stresses are shared. In addition, there are multiple ways for plants to respond to environmental stress, depending on the species and life strategy, but also multiple ways within a species depending on plant variety or ecotype. It is regularly accepted that populations of a single species originating from diverse geographic origins and/or that have been subjected to different selective pressure, have evolved retaining the best alleles for completing their life cycle. Therefore, the study of natural variation in response to abiotic stress, can help unravel key genes and alleles for plants to cope with their unfavourable physical and chemical surroundings. This review is focusing on Arabidopsis thaliana which has been largely adopted by the global scientific community as a model organism. Also, tools and data that facilitate investigation of natural variation and abiotic stress encountered in the wild are set out. Characterization of accessions, QTLs detection and cloning of alleles responsible for variation are presented. Full article
(This article belongs to the Special Issue Biotic and Abiotic Stress)
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143 KiB  
Review
The Role of Probiotics in the Poultry Industry
by S. M. Lutful Kabir
Int. J. Mol. Sci. 2009, 10(8), 3531-3546; https://doi.org/10.3390/ijms10083531 - 12 Aug 2009
Cited by 384 | Viewed by 34421
Abstract
The increase of productivity in the poultry industry has been accompanied by various impacts, including emergence of a large variety of pathogens and bacterial resistance. These impacts are in part due to the indiscriminate use of chemotherapeutic agents as a result of management [...] Read more.
The increase of productivity in the poultry industry has been accompanied by various impacts, including emergence of a large variety of pathogens and bacterial resistance. These impacts are in part due to the indiscriminate use of chemotherapeutic agents as a result of management practices in rearing cycles. This review provides a summary of the use of probiotics for prevention of bacterial diseases in poultry, as well as demonstrating the potential role of probiotics in the growth performance and immune response of poultry, safety and wholesomeness of dressed poultry meat evidencing consumer’s protection, with a critical evaluation of results obtained to date. Full article
(This article belongs to the Special Issue Antimicrobial Agents)
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134 KiB  
Review
Antihypertensive Properties of Plant-Based Prebiotics
by Siok-Koon Yeo, Lay-Gaik Ooi, Ting-Jin Lim and Min-Tze Liong
Int. J. Mol. Sci. 2009, 10(8), 3517-3530; https://doi.org/10.3390/ijms10083517 - 10 Aug 2009
Cited by 37 | Viewed by 17414
Abstract
Hypertension is one of the major risk factors for cardiovascular disease. Although various drugs for its treatment have been synthesized, the occurring side effects have generated the need for natural interventions for the treatment and prevention of hypertension. Dietary intervention such as the [...] Read more.
Hypertension is one of the major risk factors for cardiovascular disease. Although various drugs for its treatment have been synthesized, the occurring side effects have generated the need for natural interventions for the treatment and prevention of hypertension. Dietary intervention such as the administration of prebiotics has been seen as a highly acceptable approach. Prebiotics are indigestible food ingredients that bypass digestion and reach the lower gut as substrates for indigenous microflora. Most of the prebiotics used as food adjuncts, such as inulin, fructooligosaccharides, dietary fiber and gums, are derived from plants. Experimental evidence from recent studies has suggested that prebiotics are capable of reducing and preventing hypertension. This paper will discuss some of the mechanisms involved, the evidence generated from both in-vitro experiments and in-vivo trials and some controversial findings that are raised. Full article
350 KiB  
Article
Theoretical Study for High-Energy-Density Compounds Derived from Cyclophosphazene. IV. DFT Studies on 1,1-Diamino-3,3,5,5,7,7-hexaazidocyclotetraphosphazene and Its Isomers
by Jianguo Zhang, Huihui Zheng, Tonglai Zhang and Man Wu
Int. J. Mol. Sci. 2009, 10(8), 3502-3516; https://doi.org/10.3390/ijms10083502 - 06 Aug 2009
Cited by 4 | Viewed by 11668
Abstract
In the present study, a theoretical study of 1,1-diaminohexaazidocyclo-tetraphophazene (DAHA) and its isomers has been performed, using quantum computational density functional theory (B3LYP and B3PW91 methods) with 6-31G* and 6-31G** basis sets implemented in Gaussian 03 program suite. Molecular structure and bonding, vibrational [...] Read more.
In the present study, a theoretical study of 1,1-diaminohexaazidocyclo-tetraphophazene (DAHA) and its isomers has been performed, using quantum computational density functional theory (B3LYP and B3PW91 methods) with 6-31G* and 6-31G** basis sets implemented in Gaussian 03 program suite. Molecular structure and bonding, vibrational frequencies, Milliken population analysis, and natural bond orbit (NBO) have been studied. The heats of formation from atomization energies have also been calculated based on the optimized geometry. The obtained heats of formation data are compared with their homologous cyclophosphazene in order to demonstrate the accuracy of the methods, which indicate that the studied compounds might be potentially used as high energetic materials. In addition, the relative stability of five isomers have been deduced based on the total energy and the gap of frontier orbital energies. Full article
(This article belongs to the Special Issue Applications of Density Functional Theory)
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2021 KiB  
Article
Conformational Analysis of Thioether Musks Using Density Functional Theory
by William N. Setzer
Int. J. Mol. Sci. 2009, 10(8), 3488-3501; https://doi.org/10.3390/ijms10083488 - 04 Aug 2009
Cited by 4 | Viewed by 12671
Abstract
A conformational analysis of nine macrocyclic thioether musks has been carried out using molecular mechanics (MMFF), density functional theory (DFT) using both B3LYP and M06 functionals, as well as Hartree-Fock and post-Hartree-Fock (MP2) ab initio methods. 6-Thia-, 10-thia- and 4-methyl-5-thia-14-tetradecananolide, 4-thia-, 7-thia-, 11-thia- [...] Read more.
A conformational analysis of nine macrocyclic thioether musks has been carried out using molecular mechanics (MMFF), density functional theory (DFT) using both B3LYP and M06 functionals, as well as Hartree-Fock and post-Hartree-Fock (MP2) ab initio methods. 6-Thia-, 10-thia- and 4-methyl-5-thia-14-tetradecananolide, 4-thia-, 7-thia-, 11-thia- and 12-thia-15-pentadecanolide and 6-thia- and 12-thia-16-hexadecanolide were modeled. Unfortunately, there was little agreement between the computational methods at the levels of theory used in this study. Full article
(This article belongs to the Special Issue Applications of Density Functional Theory)
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795 KiB  
Article
Accurate Analysis of Tumor Margins Using a Fluorescent pH Low Insertion Peptide (pHLIP)
by James Segala, Donald M. Engelman, Yana K. Reshetnyak and Oleg A. Andreev
Int. J. Mol. Sci. 2009, 10(8), 3478-3487; https://doi.org/10.3390/ijms10083478 - 04 Aug 2009
Cited by 26 | Viewed by 13995
Abstract
The recurrence of certain cancers remains quite high due to either incomplete surgical removal of the primary tumor or the presence of small metastases that are invisible to the surgeon. Near infrared (NIR) fluorescence imaging might improve surgical outcomes by providing sensitive, specific, [...] Read more.
The recurrence of certain cancers remains quite high due to either incomplete surgical removal of the primary tumor or the presence of small metastases that are invisible to the surgeon. Near infrared (NIR) fluorescence imaging might improve surgical outcomes by providing sensitive, specific, and real-time visualization of normal and diseased tissues if agents can be found that discriminate between normal and diseased tissue and define tumor margins. We have developed a new approach for revealing tumor borders by using NIR fluorescently labeled pH Low Insertion Peptide (pHLIP) and have created a computational program for the quantitative assessment of tumor boundaries. The approach is tested in vivo by co-localization of GFP-tumors and NIR emission from the fluorescently labeled pHLIP, and it is found that boundaries are accurately reported and that sub-millimeter masses can be detected. Full article
(This article belongs to the Special Issue Algorithms and Molecular Sciences)
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2273 KiB  
Review
Analysis of Cooperativity by Isothermal Titration Calorimetry
by Alan Brown
Int. J. Mol. Sci. 2009, 10(8), 3457-3477; https://doi.org/10.3390/ijms10083457 - 04 Aug 2009
Cited by 99 | Viewed by 16814
Abstract
Cooperative binding pervades Nature. This review discusses the use of isothermal titration calorimetry (ITC) in the identification and characterisation of cooperativity in biological interactions. ITC has broad scope in the analysis of cooperativity as it determines binding stiochiometries, affinities and thermodynamic parameters, including [...] Read more.
Cooperative binding pervades Nature. This review discusses the use of isothermal titration calorimetry (ITC) in the identification and characterisation of cooperativity in biological interactions. ITC has broad scope in the analysis of cooperativity as it determines binding stiochiometries, affinities and thermodynamic parameters, including enthalpy and entropy in a single experiment. Examples from the literature are used to demonstrate the applicability of ITC in the characterisation of cooperative systems. Full article
(This article belongs to the Special Issue Isothermal Titration Calorimetry)
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355 KiB  
Article
The Role of Bloom Index of Gelatin on the Interaction with Retinal Pigment Epithelial Cells
by Jui Yang Lai
Int. J. Mol. Sci. 2009, 10(8), 3442-3456; https://doi.org/10.3390/ijms10083442 - 03 Aug 2009
Cited by 49 | Viewed by 12432
Abstract
Biocompatible materials are of considerable interest in the development of cell/drug delivery carriers for therapeutic applications. This paper investigates the effects of the Bloom index of gelatin on its interaction with retinal pigment epithelial (RPE) cells. Following two days of culture of ARPE-19 [...] Read more.
Biocompatible materials are of considerable interest in the development of cell/drug delivery carriers for therapeutic applications. This paper investigates the effects of the Bloom index of gelatin on its interaction with retinal pigment epithelial (RPE) cells. Following two days of culture of ARPE-19 cells with gelatin samples G75-100, G175, and G300, the in vitro biocompatibility was determined by cell proliferation and viability assays, and glutamate uptake measurements, as well as cytokine expression analyses. The mitochondrial dehydrogenase activity in the G300 groups was significantly lower than that of G75-100 and G175 groups. The Live/Dead assays also showed that the gelatin samples G300 induced mild cytotoxicity. In comparison with the treatment of gelatins with low Bloom index, the exposure to high Bloom strength gelatins markedly reduced the glutamate uptake capacity of ARPE-19 cells. One possible explanation for these observations is that the presence of gelatin samples G300 with high viscosity in the medium may affect the nutrient availability to cultured cells. The analyses of pro-inflammatory cytokine IL-6 expression at both mRNA and protein levels showed that the gelatins with low Bloom index caused less cellular inflammatory reaction and had more acceptable biocompatibility than their high Bloom strength counterparts. These findings suggest that the Bloom index gives influence on cellular responses to gelatin materials. Full article
(This article belongs to the Special Issue Biocompatibility of Materials)
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1534 KiB  
Article
RNA Relics and Origin of Life
by Jacques Demongeot, Nicolas Glade, Andrés Moreira and Laurent Vial
Int. J. Mol. Sci. 2009, 10(8), 3420-3441; https://doi.org/10.3390/ijms10083420 - 31 Jul 2009
Cited by 20 | Viewed by 16486
Abstract
A number of small RNA sequences, located in different non-coding sequences and highly preserved across the tree of life, have been suggested to be molecular fossils, of ancient (and possibly primordial) origin. On the other hand, recent years have revealed the existence of [...] Read more.
A number of small RNA sequences, located in different non-coding sequences and highly preserved across the tree of life, have been suggested to be molecular fossils, of ancient (and possibly primordial) origin. On the other hand, recent years have revealed the existence of ubiquitous roles for small RNA sequences in modern organisms, in functions ranging from cell regulation to antiviral activity. We propose that a single thread can be followed from the beginning of life in RNA structures selected only for stability reasons through the RNA relics and up to the current coevolution of RNA sequences; such an understanding would shed light both on the history and on the present development of the RNA machinery and interactions. After presenting the evidence (by comparing their sequences) that points toward a common thread, we discuss a scenario of genome coevolution (with emphasis on viral infectious processes) and finally propose a plan for the reevaluation of the stereochemical theory of the genetic code; we claim that it may still be relevant, and not only for understanding the origin of life, but also for a comprehensive picture of regulation in present-day cells. Full article
(This article belongs to the Special Issue Origin of Life)
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288 KiB  
Review
Plant Antimicrobial Agents and Their Effects on Plant and Human Pathogens
by Rocío González-Lamothe, Gabriel Mitchell, Mariza Gattuso, Moussa S. Diarra, François Malouin and Kamal Bouarab
Int. J. Mol. Sci. 2009, 10(8), 3400-3419; https://doi.org/10.3390/ijms10083400 - 31 Jul 2009
Cited by 273 | Viewed by 25397
Abstract
To protect themselves, plants accumulate an armoury of antimicrobial secondary metabolites. Some metabolites represent constitutive chemical barriers to microbial attack (phytoanticipins) and others inducible antimicrobials (phytoalexins). They are extensively studied as promising plant and human disease-controlling agents. This review discusses the bioactivity of [...] Read more.
To protect themselves, plants accumulate an armoury of antimicrobial secondary metabolites. Some metabolites represent constitutive chemical barriers to microbial attack (phytoanticipins) and others inducible antimicrobials (phytoalexins). They are extensively studied as promising plant and human disease-controlling agents. This review discusses the bioactivity of several phytoalexins and phytoanticipins defending plants against fungal and bacterial aggressors and those with antibacterial activities against pathogens affecting humans such as Pseudomonas aeruginosa and Staphylococcus aureus involved in respiratory infections of cystic fibrosis patients. The utility of plant products as “antibiotic potentiators” and “virulence attenuators” is also described as well as some biotechnological applications in phytoprotection. Full article
(This article belongs to the Special Issue Antimicrobial Agents)
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533 KiB  
Review
Chemical Diversity and Defence Metabolism: How Plants Cope with Pathogens and Ozone Pollution
by Marcello Iriti and Franco Faoro
Int. J. Mol. Sci. 2009, 10(8), 3371-3399; https://doi.org/10.3390/ijms10083371 - 30 Jul 2009
Cited by 213 | Viewed by 22652
Abstract
Chemical defences represent a main trait of the plant innate immune system. Besides regulating the relationship between plants and their ecosystems, phytochemicals are involved both in resistance against pathogens and in tolerance towards abiotic stresses, such as atmospheric pollution. Plant defence metabolites arise [...] Read more.
Chemical defences represent a main trait of the plant innate immune system. Besides regulating the relationship between plants and their ecosystems, phytochemicals are involved both in resistance against pathogens and in tolerance towards abiotic stresses, such as atmospheric pollution. Plant defence metabolites arise from the main secondary metabolic routes, the phenylpropanoid, the isoprenoid and the alkaloid pathways. In plants, antibiotic compounds can be both preformed (phytoanticipins) and inducible (phytoalexins), the former including saponins, cyanogenic glycosides and glucosinolates. Chronic exposure to tropospheric ozone (O3) stimulates the carbon fluxes from the primary to the secondary metabolic pathways to a great extent, inducing a shift of the available resources in favour of the synthesis of secondary products. In some cases, the plant defence responses against pathogens and environmental pollutants may overlap, leading to the unspecific synthesis of similar molecules, such as phenylpropanoids. Exposure to ozone can also modify the pattern of biogenic volatile organic compounds (BVOC), emitted from plant in response to herbivore feeding, thus altering the tritrophic interaction among plant, phytophagy and their natural enemies. Finally, the synthesis of ethylene and polyamines can be regulated by ozone at level of S-adenosylmethionine (SAM), the biosynthetic precursor of both classes of hormones, which can, therefore, mutually inhibit their own biosynthesis with consequence on plant phenotype. Full article
(This article belongs to the Special Issue Biotic and Abiotic Stress)
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473 KiB  
Article
Computational Study on the Conformation and Vibration Frequencies of β-Sheet of ε-Polylysine in Vacuum
by Shiru Jia, Zhiwen Mo, Yujie Dai, Xiuli Zhang, Hongjiang Yang and Yuhua Qi
Int. J. Mol. Sci. 2009, 10(8), 3358-3370; https://doi.org/10.3390/ijms10083358 - 29 Jul 2009
Cited by 11 | Viewed by 11278
Abstract
Two oligomers, each containing 3 L-lysine residues, were used as model molecules for the simulation of the β-sheet conformation of ε-polylysine (ε-PLL) chains. Their C terminals were capped with ethylamine and N terminals were capped with α-L-aminobutanoic acid, respectively. The calculations were carried [...] Read more.
Two oligomers, each containing 3 L-lysine residues, were used as model molecules for the simulation of the β-sheet conformation of ε-polylysine (ε-PLL) chains. Their C terminals were capped with ethylamine and N terminals were capped with α-L-aminobutanoic acid, respectively. The calculations were carried out with the hybrid two-level ONOIM (B3LYP/6-31G:PM3) computational chemistry method. The optimized conformation was obtained and IR frequencies were compared with experimental data. The result indicated that the two chains were winded around each other to form a distinct cyclohepta structure through bifurcated hydrogen bonds. The groups of amide and α-amidocyanogen coming from one chain and the carbonyl group from the other chain were involved in the cyclohepta structure. The bond angle of the bifurcated hydrogen bonds was 66.6°. The frequency analysis at ONIOM [B3LYP/6-31G (d):PM3] level showed the IR absorbances of the main groups, such as the amide and amidocyanogen groups, were in accordance with the experimental data. Full article
(This article belongs to the Section Physical Chemistry, Theoretical and Computational Chemistry)
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180 KiB  
Article
Inhibition of Citrinin-Induced Apoptotic Biochemical Signaling in Human Hepatoma G2 Cells by Resveratrol
by Chia-Chi Chen and Wen-Hsiung Chan
Int. J. Mol. Sci. 2009, 10(8), 3338-3357; https://doi.org/10.3390/ijms10083338 - 29 Jul 2009
Cited by 53 | Viewed by 10811
Abstract
The mycotoxin citrinin (CTN), a natural contaminant in foodstuffs and animal feeds, exerts cytotoxic and genotoxic effects on various mammalian cells. CTN causes cell injury, including apoptosis, but its precise regulatory mechanisms of action are currently unclear. Resveratrol, a member of the phytoalexin [...] Read more.
The mycotoxin citrinin (CTN), a natural contaminant in foodstuffs and animal feeds, exerts cytotoxic and genotoxic effects on various mammalian cells. CTN causes cell injury, including apoptosis, but its precise regulatory mechanisms of action are currently unclear. Resveratrol, a member of the phytoalexin family found in grapes and other dietary plants, possesses antioxidant and anti-tumor properties. In the present study, we examined the effects of resveratrol on apoptotic biochemical events in Hep G2 cells induced by CTN. Resveratrol inhibited CTN-induced ROS generation, activation of JNK, loss of mitochondrial membrane potential (MMP), as well as activation of caspase-9, caspase-3 and PAK2. Moreover, resveratrol and the ROS scavengers, NAC and α-tocopherol, abolished CTN-stimulated intracellular oxidative stress and apoptosis. Active JNK was required for CTN-induced mitochondria-dependent apoptotic biochemical changes, including loss of MMP, and activation of caspases and PAK2. Activation of PAK2 was essential for apoptosis triggered by CTN. These results collectively demonstrate that CTN stimulates ROS generation and JNK activation for mitochondria-dependent apoptotic signaling in Hep G2 cells, and these apoptotic biochemical events are blocked by pretreatment with resveratrol, which exerts antioxidant effects. Full article
(This article belongs to the Section Biochemistry)
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258 KiB  
Article
Classification of 5-HT1A Receptor Ligands on the Basis of Their Binding Affinities by Using PSO-Adaboost-SVM
by Zhengjun Cheng, Yuntao Zhang, Changhong Zhou, Wenjun Zhang and Shibo Gao
Int. J. Mol. Sci. 2009, 10(8), 3316-3337; https://doi.org/10.3390/ijms10083316 - 29 Jul 2009
Cited by 8 | Viewed by 10838
Abstract
In the present work, the support vector machine (SVM) and Adaboost-SVM have been used to develop a classification model as a potential screening mechanism for a novel series of 5-HT1A selective ligands. Each compound is represented by calculated structural descriptors that encode [...] Read more.
In the present work, the support vector machine (SVM) and Adaboost-SVM have been used to develop a classification model as a potential screening mechanism for a novel series of 5-HT1A selective ligands. Each compound is represented by calculated structural descriptors that encode topological features. The particle swarm optimization (PSO) and the stepwise multiple linear regression (Stepwise-MLR) methods have been used to search descriptor space and select the descriptors which are responsible for the inhibitory activity of these compounds. The model containing seven descriptors found by Adaboost-SVM, has showed better predictive capability than the other models. The total accuracy in prediction for the training and test set is 100.0% and 95.0% for PSO-Adaboost-SVM, 99.1% and 92.5% for PSO-SVM, 99.1% and 82.5% for Stepwise-MLR-Adaboost-SVM, 99.1% and 77.5% for Stepwise-MLR-SVM, respectively. The results indicate that Adaboost-SVM can be used as a useful modeling tool for QSAR studies. Full article
(This article belongs to the Section Physical Chemistry, Theoretical and Computational Chemistry)
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340 KiB  
Review
Isothermal Microcalorimetry to Investigate Non Specific Interactions in Biophysical Chemistry
by Vincent Ball and Clarisse Maechling
Int. J. Mol. Sci. 2009, 10(8), 3283-3315; https://doi.org/10.3390/ijms10083283 - 28 Jul 2009
Cited by 69 | Viewed by 16309
Abstract
Isothermal titration microcalorimetry (ITC) is mostly used to investigate the thermodynamics of “specific” host-guest interactions in biology as well as in supramolecular chemistry. The aim of this review is to demonstrate that ITC can also provide useful information about non-specific interactions, like [...] Read more.
Isothermal titration microcalorimetry (ITC) is mostly used to investigate the thermodynamics of “specific” host-guest interactions in biology as well as in supramolecular chemistry. The aim of this review is to demonstrate that ITC can also provide useful information about non-specific interactions, like electrostatic or hydrophobic interactions. More attention will be given in the use of ITC to investigate polyelectrolyte-polyelectrolyte (in particular DNA-polycation), polyelectrolyte-protein as well as protein-lipid interactions. We will emphasize that in most cases these “non specific” interactions, as their definition will indicate, are favoured or even driven by an increase in the entropy of the system. The origin of this entropy increase will be discussed for some particular systems. We will also show that in many cases entropy-enthalpy compensation phenomena occur. Full article
(This article belongs to the Special Issue Isothermal Titration Calorimetry)
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438 KiB  
Article
Characterization of the Sesbania rostrata Phytochelatin Synthase Gene: Alternative Splicing and Function of Four Isoforms
by An-Ming Li, Bing-Yun Yu, Fu-Hua Chen, Hui-Yan Gan, Jian-Gang Yuan, Rongliang Qiu, Jun-Chao Huang, Zhong-Yi Yang and Zeng-Fu Xu
Int. J. Mol. Sci. 2009, 10(8), 3269-3282; https://doi.org/10.3390/ijms10083269 - 24 Jul 2009
Cited by 13 | Viewed by 14583
Abstract
Phytochelatins (PCs) play an important role in detoxification of heavy metals in plants. PCs are synthesized from glutathione by phytochelatin synthase (PCS), a dipeptidyltransferase. Sesbania rostrata is a tropical legume plant that can tolerate high concentrations of Cd and Zn. In this study, [...] Read more.
Phytochelatins (PCs) play an important role in detoxification of heavy metals in plants. PCs are synthesized from glutathione by phytochelatin synthase (PCS), a dipeptidyltransferase. Sesbania rostrata is a tropical legume plant that can tolerate high concentrations of Cd and Zn. In this study, the S. rostrata PCS gene (SrPCS) and cDNAs were isolated and characterized. Southern blot and sequence analysis revealed that a single copy of the SrPCS gene occurs in the S. rostrata genome, and produces four different SrPCS mRNAs and proteins, SrPCS1-SrPCS4, by alternative splicing of the SrPCS pre-mRNA. The SrPCS1 and SrPCS3 proteins conferred Cd tolerance when expressed in yeast cells, whereas the SrPCS2 and SrPCS4 proteins, which lack the catalytic triad and the N-terminal domains, did not. These results suggested that SrPCS1 and SrPCS3 have potential applications in genetic engineering of plants for enhancing heavy metal tolerance and phytoremediation of contaminated soils. Full article
(This article belongs to the Special Issue Biotic and Abiotic Stress)
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