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Diverse Modes (diverse + mode)
Selected AbstractsDiverse modes of 5,-[4-(aminoiminomethyl)phenyl]-[2,2,-bifuran]-5-carboximidamide (DB832) interaction with multi-stranded DNA structuresBIOPOLYMERS, Issue 1 2010Dmitry N. Kaluzhny Abstract The modes of binding of 5,-[4-(aminoiminomethyl)phenyl]-[2,2,-Bifuran]-5-carboximidamide (DB832) to multi-stranded DNAs: human telomere quadruplex, monomolecular R-triplex, pyr/pur/pyr triplex consisting of 12 T*(T·A) triplets, and DNA double helical hairpin were studied. The optical adsorption of the ligand was used for monitoring the binding and for determination of the association constants and the numbers of binding sites. CD spectra of DB832 complexes with the oligonucleotides and the data on the energy transfer from DNA bases to the bound DB832 assisted in elucidating the binding modes. The affinity of DB832 to the studied multi-stranded DNAs was found to be greater (Kass , 107M,1) than to the duplex DNA (Kass , 2 × 105M,1). A considerable stabilizing effect of DB832 binding on R-triplex conformation was detected. The nature of the ligand tight binding differed for the studied multi-stranded DNA depending on their specific conformational features: recombination-type R-triplex demonstrated the highest affinity for DB832 groove binding, while pyr/pur/pyr TTA triplex favored DB832 intercalation at the end stacking contacts and the human telomere quadruplex d[AG3(T2AG3)3] accommodated the ligand in a capping mode. Additionally, the pyr/pur/pyr TTA triplex and d[AG3(T2AG3)3] quadruplex bound DB832 into their grooves, though with a markedly lesser affinity. DB832 may be useful for discrimination of the multi-sranded DNA conformations and for R-triplex stabilization. © 2009 Wiley Periodicals, Inc. Biopolymers 93: 8,20, 2010. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] Bacteria 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] ,Practice without theory': a neuroanthropological perspective on embodied learningTHE JOURNAL OF THE ROYAL ANTHROPOLOGICAL INSTITUTE, Issue 2010Greg Downey This paper, drawing on research on skill acquisition and sports training, asks two questions. First, how does the mimetic channel function and thus limit what can be acquired by bodily enculturation? Second, given that it was acquired through imitation, what must be the nature of the resulting bodily knowledge? These questions are addressed through a close examination of movement education, especially its neurological, psychological, and interactional dynamics in the Afro-Brazilian art capoeira. The study of embodied knowledge and its development in bodily practices suggests that gaining bodily skills requires more than ,knowledge', involving changes in physiology, perception, comportment, and behaviour patterns in unsystematic, diverse modes. Embodied knowledge from this perspective appears more complex, less systematic or susceptible to structural account, than typically modelled. Résumé À partir de travaux sur l'acquisition de compétences et l'entraînement sportif, l'article pose deux questions. D'une part, comment fonctionne le canal mimétique, et comment limite-t-il ce qui peut être acquis par une enculturation corporelle ? D'autre part, sachant que l'apprentissage s'est fait par imitation, quelle peut être la nature des connaissances corporelles en résultant ? Ces questions sont abordées par le biais d'un examen attentif de l'éducation au mouvement, et notamment de sa dynamique neurologique, psychologique et interactive, dans l'art afro-brésilien de la capoeira. L'étude des connaissances incorporées et de leur développement dans les pratiques corporelles suggère que l'acquisition de compétences physiques nécessite plus que des « connaissances » et implique des changements physiologiques, perceptifs et comportementaux de nature diverse et non systématique. De ce point de vue, les connaissances incorporées semblent plus complexes, moins systématiques ou susceptibles de faire l'objet d'un compte-rendu structural, que dans les modèles classiques. [source] Characterization of a new xyloglucan endotransglucosylase/hydrolase (XTH) from ripening tomato fruit and implications for the diverse modes of enzymic actionTHE PLANT JOURNAL, Issue 2 2006Montserrat Saladié Summary Xyloglucan endotransglucosylase/hydrolases (XTHs) are cell wall-modifying enzymes that align within three or four distinct phylogenetic subgroups. One explanation for this grouping is association with different enzymic modes of action, as XTHs can have xyloglucan endotransglucosylase (XET) or endohydrolase (XEH) activities. While Group 1 and 2 XTHs predominantly exhibit XET activity, to date the activity of only one member of Group 3 has been reported: nasturtium TmXH1, which has a highly specialized function and hydrolyses seed-storage xyloglucan rather than modifying cell wall structure. Tomato fruit ripening was selected as a model to test the hypothesis that preferential XEH activity might be a defining characteristic of Group 3 XTHs, which would be expressed during processes where net xyloglucan depolymerization occurs. Database searches identified 25 tomato XTHs, and one gene (SlXTH5) was of particular interest as it aligned within Group 3 and was expressed abundantly during ripening. Recombinant SlXTH5 protein acted primarily as a transglucosylase in vitro and depolymerized xyloglucan more rapidly in the presence than in the absence of xyloglucan oligosaccharides (XGOs), indicative of XET activity. Thus, there is no correlation between the XTH phylogenetic grouping and the preferential enzymic activities (XET or XEH) of the proteins in those groups. Similar analyses of SlXTH2, a Group 2 tomato XTH, and nasturtium seed TmXTH1 revealed a spectrum of modes of action, suggesting that all XTHs have the capacity to function in both modes. The biomechanical properties of plant walls were unaffected by incubation with SlXTH5, with or without XGOs, suggesting that XTHs do not represent primary cell wall-loosening agents. The possible roles of SlXTH5 in vivo are discussed. [source] Mode of pollen tube growth in pistils of Ticodendron incognitum (Ticodendraceae, Fagales) and the evolution of chalazogamyBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2008AKIKO SOGO Ticodendron incognitum is the sole species of the Ticodendraceae, which was established as a new family in the Fagales less than 20 years ago. Considering the diverse modes of pollen tube growth observed in other Fagales, we investigated the growth of pollen tubes in the pistil of Ticodendron. At the time of pollination, T. incognitum had four immature ovules in a bilocular ovary, thus exhibiting delayed fertilization, as in other Fagales. During the period when fertilization was delayed, pollen tube growth in the pistil was intermittent, consisting of five steps associated with development of the ovules and embryo sacs. Four cessation sites occurred: in the style, in the tissue of the upper part of the ovary, inside and outside of the funicle and at the chalaza. A single pollen tube eventually reaches a mature embryo sac through the chalaza in one of the four ovules. While both delayed fertilization and intermittent pollen tube growth play a role in male and female gametophyte selection, as in other Fagales, the five-step process of pollen tube growth through the chalaza (i.e. chalazogamy) is characteristic of lineages of the Casuarinaceae, Ticodendraceae and Betulaceae (the latter with the loss of one step). © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157, 621,631. [source] | ||||||||||