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Soybean Seed Extracts Preferentially Express Genomic Loci of Bradyrhizobium japonicum |
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Written by Administrator
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Sunday, 01 June 2008 |
DNA Res. 2008 May 29;
Authors: Wei M, Yokoyama T, Minamisawa K, Mitsui H, Itakura M, Kaneko T, Tabata S, Saeki K, Omori H, Tajima S, Uchiumi T, Abe M, Ohwada T
Initial interaction between rhizobia and legumes actually starts via encounters of both partners in the rhizosphere. In this study, the global expression profiles of Bradyrhizobium japonicum USDA 110 in response to soybean (Glycine max) seed extracts (SSE) and genistein, a major soybean-released isoflavone for nod genes induction of B. japonicum, were compared. SSE induced many genomic loci as compared with genistein (5.0 microM), nevertheless SSE-supplemented medium contained 4.7 microM genistein. SSE markedly induced four predominant genomic regions within a large symbiosis island (681 kb), which include tts genes (type III secretion system) and various nod genes. In addition, SSE-treated cells expressed many genomic loci containing genes for polygalacturonase (cell-wall degradation), exopolysaccharide synthesis, 1-aminocyclopropane-1-carboxylate deaminase, ribosome proteins family and energy metabolism even outside symbiosis island. On the other hand, genistein-treated cells exclusively showed one expression cluster including common nod gene operon within symbiosis island and six expression loci including multidrug resistance, which were shared with SSE-treated cells. Twelve putatively regulated genes were indeed validated by quantitative RT-PCR. Several SSE-induced genomic loci likely participate in the initial interaction with legumes. Thus, these results can provide a basic knowledge for screening novel genes relevant to the B. japonicum- soybean symbiosis.
PMID: 18511436 [PubMed - as supplied by publisher] |
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Permanent Embryo Arrest: Molecular and Cellular Concepts |
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Written by Administrator
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Sunday, 01 June 2008 |
Mol Hum Reprod. 2008 May 29;
Authors: Betts DH, Madan P
Developmental arrest is one of the mechanisms responsible for the elevated levels of embryo demise during the first week of in vitro development. Approximately 10-15% of IVF embryos permanently arrest in mitosis at the 2-4-cell cleavage stage showing no indication of apoptosis. Reactive oxygen species (ROS) are implicated in this process and must be controlled in order to optimize embryo production. A stress sensor that can provide a key understanding of permanent cell cycle arrest and link ROS with cellular signaling pathway(s) is p66Shc, an adaptor protein for apoptotic response to oxidative stress. Deletion of the p66Shc gene in mice results in extended lifespan, which is linked to their enhanced resistance to oxidative stress and reduced levels of apoptosis. P66Shc has been shown to generate mitochondrial H(2)O(2) to trigger apoptosis, but may also serve as an integration point for many signaling pathways that affect mitochondrial function. We have detected elevated levels of p66Shc and ROS within arrested embryos and believe that p66Shc plays a central role in regulating permanent embryo arrest. In this paper we review the cellular and molecular aspects of permanent embryo arrest and speculate on the mechanism(s) and etiology of this method of embryo demise.
PMID: 18511487 [PubMed - as supplied by publisher] |
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The innate immune system of mammals and insects |
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Written by Administrator
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Sunday, 01 June 2008 |
Contrib Microbiol. 2008;15:21-44
Authors: Müller U, Vogel P, Alber G, Schaub GA
Infectious agents threaten any organism. Therefore, mammals and insects have evolved a complex network of cells and humoral factors termed immune system able to control and eliminate pathogens. Immunity varies between different groups of animals but always contains an innate immune system that can act fast and often effectively against a wide range of distinct pathogens (i.e. viruses, bacteria, fungi, and eukaryotic parasites). In mammals and insects, the communication between and regulation of immune cells is carried out by cytokines which orchestrate the defense against the invaders. The major challenge to recognize and to fight pathogens is the same for any host. In insects and mammals, the pathogens are recognized as non-self by recognition of pathogen-associated molecular patterns. In addition, similar pathogen recognition receptors and signaling pathways activate the immune response in insects and mammals. The pathogens have to be opsonized and/or ingested and controlled/eliminated by antimicrobial peptides or small effector molecules (reactive oxygen and nitrogen intermediates). Interestingly, even invertebrates have evolved certain forms of adaptive immunity, i.e. specific immune priming, and in some invertebrates alternative splicing of pathogen recognition receptors allows for a more specific recognition of a wide variety of pathogens. This enhanced specificity of pattern recognition conveys a special form of memory to their invertebrate hosts. In this chapter, we also consider gut immunity of insects and compare it with the response in mammals.
PMID: 18511854 [PubMed - in process]
Permanent Embryo Arrest: Molecular and Cellular Concepts. |
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The role of nutrients in modulating disease |
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Written by Administrator
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Saturday, 31 May 2008 |
The role of nutrients in modulating disease. J Small Anim Pract. 2008 Jun;49(6):266-71 Authors: Chan DL The role of nutrition in the management of diseases has often centred on correcting apparent nutrient deficiencies or meeting estimated nutritional requirements of patients. Nutrition has traditionally been considered a supportive measure akin to fluid therapy and rarely it has been considered a primary means of ameliorating diseases. Recently, however, further understanding of the underlying mechanisms of various disease processes and how certain nutrients possess pharmacological properties have fuelled an interest in exploring how nutritional therapies themselves could modify the behaviour of various conditions. Nutrients such as omega-3 fatty acids, antioxidants and certain amino acids such as arginine and glutamine have all been demonstrated to have at least the potential to modulate diseases. Developments in the area of critical care nutrition have been particularly exciting as nutritional therapies utilising a combination of approaches have been shown to positively impact outcome beyond simply proving substrate for synthesis and energy. Application of certain nutrients for the modulation of diseases in veterinary patients is still in early stages, but apparent successes have already been demonstrated, and future studies are warranted to establish optimal approaches. This review describes the rationale of many of these approaches and discusses findings both in human beings and in animals, which may guide future therapy. PMID: 18510496 [PubMed - in process] |
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Last Updated ( Sunday, 01 June 2008 )
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Comparative genomics of serotype Asia 1 foot-and-mouth disease virus isolates from India |
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Written by Administrator
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Saturday, 31 May 2008 |
Virus Res. 2008 May 27;
Authors: Mohapatra JK, Sanyal A, Hemadri D, Tosh C, Biswas S, Knowles NJ, Rasool TJ, Bandyopadhyay SK, Pattnaik B
This study deals with a comparative analysis of complete genome sequences of twenty-one serotype Asia 1 foot-and-mouth disease (FMD) field viruses isolated over a period of two decades from India, two vaccine strains and seven exotic sequences. The Indian viruses could be grouped in to three distinct lineages at the entire coding region, evolving independently probably under differential selection pressure as evident from the lineage-specific signatures identified. This comparison revealed 80% of amino acids at the polyprotein region to be invariant. Twenty-one residues in L, 3A and P1 region were identified to be under positive selection of which some are antigenically critical. Analysis at functionally crucial motifs, receptor contact residues, polyprotein cleavage sites and at putative T-cell epitopes expands the knowledge beyond other serotypes. Antigenic site II in betaB-betaC loop of VP2 was highly unstable suggesting its exposure to extreme immune pressure. A single cross-over at the L proteinase region in an isolate from buffalo, also featuring an extensive deletion at the 5' untranslated region (UTR), reflects the role of intraserotypic genetic recombination in natural evolution. The likely biological relevance of deletions/insertions observed at UTRs, VP1 and 3A could not be deduced. Altogether, a substantial amount of data raised on full length genomes of type Asia 1 virus adds value to the FMD virus genomics.
PMID: 18511143 [PubMed - as supplied by publisher] |
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Last Updated ( Sunday, 01 June 2008 )
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