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Molecular Biological Approaches (molecular + biological_approach)
Selected AbstractsBacteria used in the biological control of plant-parasitic nematodes: populations, mechanisms of action, and future prospectsFEMS MICROBIOLOGY ECOLOGY, Issue 2 2007Baoyu Tian Abstract As a group of important natural enemies of nematode pests, nematophagous bacteria exhibit diverse modes of action: these include parasitizing; producing toxins, antibiotics, or enzymes; competing for nutrients; inducing systemic resistance of plants; and promoting plant health. They act synergistically on nematodes through the direct suppression of nematodes, promoting plant growth, and facilitating the rhizosphere colonization and activity of microbial antagonists. This review details the nematophagous bacteria known to date, including parasitic bacteria, opportunistic parasitic bacteria, rhizobacteria, Cry protein-forming bacteria, endophytic bacteria and symbiotic bacteria. We focus on recent research developments concerning their pathogenic mechanisms at the biochemical and molecular levels. Increased understanding of the molecular basis of the various pathogenic mechanisms of the nematophagous bacteria could potentially enhance their value as effective biological control agents. We also review a number of molecular biological approaches currently used in the study of bacterial pathogenesis in nematodes. We discuss their merits, limitations and potential uses. [source] Functional polymorphisms in dopamine and serotonin pathway genes,HUMAN MUTATION, Issue 1 2006Ursula M. D'Souza Abstract There is mounting evidence on the functional significance of single nucleotide and simple repeat sequence polymorphisms in both the coding and regulatory regions of genes in the monoamine neurotransmitter pathways. Many of these gene variants have been associated with human behavioral disorders and traits, and thus have important clinical relevance. This review summarizes the literature on the published functional studies from a molecular, cellular, and neurobiological perspective, and notes their possible behavioral consequences. Functional studies have adopted a variety of strategies. Pharmacological studies have focused on the effects of gene variation at the protein level in terms of binding to ligands or drugs. Other key investigations have determined effects on gene expression at the level of transcription in mammalian cell cultures, lymphoblasts, and/or human postmortem brain tissue. This has enabled the comparison of in vitro and in vivo data, and furthermore provides an improved perceptive of their respective advantages. Additionally, molecular biological approaches have identified transcription factors (DNA-binding proteins) that interact with the motifs within the polymorphisms themselves. Various neuroimaging studies have further determined the relationship of genotype with protein availability in the brain, and thus have contributed to our understanding of the in vivo functional significance of gene variants. Finally, there is growing evidence from both human and animal studies on the interaction of functional polymorphisms with the environment in determining a behavioral outcome. Taken together, these findings have contributed to a greater understanding of the plausible molecular mechanisms that underpin the functional significance of polymorphisms in monoamine neurotransmitter pathway genes, and how they may influence behavioral phenotypes. Hum Mutat 27(1), 1,13, 2006. © 2005 Wiley-Liss, Inc. [source] Detection of oral streptococci with collagen-binding properties in saliva specimens from mothers and their childrenINTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 4 2010RYOTA NOMURA International Journal of Paediatric Dentistry 2010; 20: 254,260 Background., Approximately 10,20% of Streptococcus mutans strains have been reported to possess collagen-binding properties, whereas other species in the oral cavity with those properties remain to be elucidated. Aim., To identify strains with collagen-binding properties and analyse their characteristics in comparison with S. mutans. Design., A total of 110 expectorated saliva specimens were collected from 55 pairs of mothers and their children. Bacterial strains with collagen-binding properties were isolated and the species specified. In addition, strains with collagen-binding properties isolated from mother,child pairs were analysed using molecular biological approaches. Results., The detection frequency of strains with collagen-binding properties was shown to be 40.9%, among which S. salivarius was the most frequently detected, followed by S. mutans. The collagen-binding activity of the S. mutans group was the highest, followed by S. salivarius. In addition, S. mutans and S. salivarius strains from 3 and 1 mother,child pairs, respectively, were shown to be the same clones. Conclusions., Our results indicate that S. mutans and S. salivarius are major species with collagen-binding properties in the oral cavity, and that strains with such properties may be related to mother,child transmission. [source] In search of new tractable diatoms for experimental biologyBIOESSAYS, Issue 7 2008Victor A. Chepurnov Diatoms are a species-rich group of photosynthetic eukaryotes, with enormous ecological significance and great potential for biotechnology. During the last decade, diatoms have begun to be studied intensively using modern molecular techniques and the genomes of four diatoms have been wholly or partially sequenced. Although new insights into the biology and evolution of diatoms are accumulating rapidly due to the availability of reverse genetic tools, the full potential of these molecular biological approaches can only be fully realized if experimental control of sexual crosses becomes firmly established and widely accessible to experimental biologists. Here we discuss the issue of choosing new models for diatom research, by taking into account the broader context of diatom mating systems and the place of sex in relation to the intricate cycle of cell size reduction and restitution that is characteristic of most diatoms. We illustrate the results of our efforts to select and develop experimental systems in diatoms, using species with typical life cycle attributes, which could be used as future model organisms to complement existing ones. BioEssays 30:692,702, 2008. © 2008 Wiley Periodicals, Inc. [source] Camellia japonica suppresses immunoglobulin E-mediated allergic response by the inhibition of Syk kinase activation in mast cellsCLINICAL & EXPERIMENTAL ALLERGY, Issue 5 2008J-H. Lee Summary Background Novel approaches are being explored to develop new therapies for various allergic diseases. Complementary and alternative medicines are considered to be promising avenues for the development of such new therapies. Objectives To investigate the effect of many Korean plants on the IgE-mediated allergic response in mast cells and in vivo, and its mechanism of action. Materials and methods The anti-allergic activity was tested by evaluating effects on degranulation of mast cells in culture and passive cutaneous anaphylaxis (PCA) in vivo. Its mechanism of action was investigated by immunoblotting analysis, immunoprecipitation, RT-PCR, and other molecular biological approaches in mast cells. Results We screened approximately 100 natural plant extracts collected in Korea for in vitro anti-allergic activity. The leaf extract of Camellia japonica (LECJ) exhibited the most potent effect on degranulation in antigen-stimulated rodent and human mast cells. LECJ reversibly inhibited degranulation in a dose-dependent manner, with IC50 values of ,50 ,g/mL for the mast cells, and it also suppressed the expression and secretion of TNF-, and IL-4 in rat basophilic leukaemia-2H3 mast cells. In agreement with its in vitro activity, LECJ significantly inhibited mast cell-mediated PCA in an animal model. LECJ inhibited activating phosphorylation of tyrosine Y371 on Syk kinase, indicating that LECJ inhibits the activity of Src-family kinases in mast cells. In the in vitro kinase assay, LECJ directly inhibited Lyn kinase, the major Src-family kinase in the cells. It also suppressed Akt and MAP kinases, which are critical for the production of various pro-inflammatory cytokines in mast cells. In high-performance liquid chromatography analysis, quercetin-3-,- d -glucoside and eugenol were identified as the major active components. Conclusion The present results strongly suggest that the anti-allergic activity of LECJ is mediated through inhibiting degranulation and allergic cytokine secretion by inhibition of Src-family kinase in mast cells and it may be useful for the treatment of mast cell-related immediate and delayed allergic diseases. [source] | |||||||||||||