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961.
Two Morphological Types of Cell Appendages on a Strongly Adhesive Bacterium, Acinetobacter sp. Strain Tol 5 总被引:1,自引:0,他引:1
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Two morphological types of appendages, an anchor-like appendage and a peritrichate fibril-type appendage, have been observed on cells of an adhesive bacterium, Acinetobacter sp. strain Tol 5, by use of recently developed electron microscopic techniques. The anchor extends straight to the substratum without branching and tethers the cell body at its end at distances of several hundred nanometers, whereas the peritrichate fibril attaches to the substratum in multiple places, fixing the cell at much shorter distances. 相似文献
962.
963.
Larry R. McLean Ying Zhang Hua Li Ziyu Li Ulrike Lukasczyk Yong-Mi Choi Zuoning Han Joy Prisco Jeremy Fordham Joseph T. Tsay Stephan Reiling Roy J. Vaz Yi Li 《Bioorganic & medicinal chemistry letters》2009,19(23):6717-6720
Biochemical and X-ray crystallographic studies confirmed that hydroxyquinoline derivatives identified by virtual screening were actually covalent inhibitors of the MIF tautomerase. Adducts were formed by N-alkylation of the Pro-1 at the catalytic site with a loss of an amino group of the inhibitor. 相似文献
964.
Daniel W. Buster Scott G. Daniel Huy Q. Nguyen Sarah L. Windler Lara C. Skwarek Maureen Peterson Meredith Roberts Joy H. Meserve Tom Hartl Joseph E. Klebba David Bilder Giovanni Bosco Gregory C. Rogers 《The Journal of cell biology》2013,201(1):49-63
Condensin complexes play vital roles in chromosome condensation during mitosis and meiosis. Condensin II uniquely localizes to chromatin throughout the cell cycle and, in addition to its mitotic duties, modulates chromosome organization and gene expression during interphase. Mitotic condensin activity is regulated by phosphorylation, but mechanisms that regulate condensin II during interphase are unclear. Here, we report that condensin II is inactivated when its subunit Cap-H2 is targeted for degradation by the SCFSlimb ubiquitin ligase complex and that disruption of this process dramatically changed interphase chromatin organization. Inhibition of SCFSlimb function reorganized interphase chromosomes into dense, compact domains and disrupted homologue pairing in both cultured Drosophila cells and in vivo, but these effects were rescued by condensin II inactivation. Furthermore, Cap-H2 stabilization distorted nuclear envelopes and dispersed Cid/CENP-A on interphase chromosomes. Therefore, SCFSlimb-mediated down-regulation of condensin II is required to maintain proper organization and morphology of the interphase nucleus. 相似文献
965.
966.
Ratnesh Kumar Tripathi Vindhya Mohindra Akanksha Singh Rajesh Kumar Rahasya Mani Mishra Joy Krushna Jena 《Journal of biosciences》2013,38(2):373-383
With an aim to study the mechanism of adaptation to acute hypoxic periods by hypoxia-tolerant catfish, Clarias batrachus, the mass-specific metabolic rate (VO2) along with its hematological parameters, metabolic response and antioxidant enzyme activities were studied. During progressive hypoxia, C. batrachus was found to be an oxyconformer and showed a steady decline in its aquatic oxygen consumption rate. When C. batrachus was exposed for different periods at experimental hypoxia level (0.98?±?0.1 mg/L, DO), hemoglobin and hematocrit concentrations were increased, along with decrease in mean cellular hemoglobin concentration, which reflected a physiological adaptation to enhance oxygen transport capacity. Significant increase in serum glucose and lactate concentration as well as lactate dehydrogenase activity was observed. Antioxidant enzymes were found to operate independently of one another, while total glutathione concentration was unaffected in any of the tissues across treatments. These observations suggested that hypoxia resulted in the development of oxidative stress and C. batrachus was able to respond through increase in the oxygen carrying capacity, metabolic depression and efficient antioxidant defense system to survive periods of acute hypoxia. 相似文献
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968.
969.
When adequate concentrations of phosphinothricin (a potent inhibitor of glutamine synthetase) are added to Anacystis nidulans cells suspended in nitrate medium, ammonia excretion into the medium takes place. Similarly, when phosphinothricin is added to nitrogen fixing cultures of Anabaena ATCC 33047, ammonia is also released at high rates. Methionine sulphoximine, phosphinothricin and its 2-oxo-derivative (1 mM) stimulate ammonia production and cause a sharp drop in glutamine and asparagine concentrations, when fed to leaves of Triticum, Pisum and Helianthus. Less pronounced effects were detected with the leaves of a C4 plant Zea. 相似文献
970.
Differential invasion of a wetland grass explained by tests of nutrients and light availability on establishment and clonal growth. 总被引:10,自引:0,他引:10
Phalaris arundinacea (Poaceae) is aggressively invading wetlands across North America. We tested the hypotheses that open canopies and increased nutrients facilitate vegetative establishment in the field, using a phytometer (6 rhizome fragments/plot, 24 plots/wetland). In each of three wetlands, phytometers received three levels of an NPK fertilizer or served as controls. Emergence and survival differed among sites (P=0.0005), but not due to NPK addition. P. arundinacea survival was highest in a wet prairie with a late-developing canopy, but limited by prolonged flooding in one sedge meadow and by an early-growing, dense plant canopy in a second. These patterns were explained in greenhouse experiments, where both flooding (P<0.0001) and heavy shade (P=0.0002) decreased P. arundinacea aboveground biomass by up to 73% and 97%, respectively. Rhizome fragment survival was reduced by 30% under flooded conditions and 25% under heavy shade. We then tested the hypothesis that a clonal subsidy facilitates vegetative expansion into heavy shade. Established clones were allowed access to bare soil under four levels of shade and two levels of NPK fertilizer in a two-factor greenhouse experiment. Young ramets attached to parent clones readily grew into heavy shade, and the high nutrient treatment increased aboveground growth (P<0.0001) and distance of ramet spread (P=0.0051) by nearly 50%. Under low nutrient conditions, root biomass increased by 30% (P<0.0001). P. arundinacea's rapid expansion into a variety of wetland types is likely a function of clonal subsidy, morphological plasticity, and nutrient availability: young ramets that emerge under shaded conditions are supported by parental subsidies; where nutrients are plentiful, P. arundinacea can maximize aboveground growth to capture more light; and where nutrients are scarce, it can increase belowground foraging. 相似文献