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161.
T cells developing in the adult thymus ultimately derive from haematopoietic stem cells in the bone marrow. Here, we summarize research into the identity of the haematopoietic progenitors that leave the bone marrow, migrate through the blood and settle in the thymus to generate T cells. Accumulating data indicate that various different bone-marrow progenitors are T-cell-lineage competent and might contribute to intrathymic T-cell development. Such developmental flexibility implies a mechanism of T-cell-lineage commitment that can operate on a range of T-cell-lineage-competent progenitors, and further indicates that only those T-cell-lineage-competent progenitors able to migrate to, and settle in, the thymus should be considered physiological T-cell progenitors. 相似文献
162.
Pathogenomic sequence analysis of Bacillus cereus and Bacillus thuringiensis isolates closely related to Bacillus anthracis 总被引:6,自引:0,他引:6
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Han CS Xie G Challacombe JF Altherr MR Bhotika SS Brown N Bruce D Campbell CS Campbell ML Chen J Chertkov O Cleland C Dimitrijevic M Doggett NA Fawcett JJ Glavina T Goodwin LA Green LD Hill KK Hitchcock P Jackson PJ Keim P Kewalramani AR Longmire J Lucas S Malfatti S McMurry K Meincke LJ Misra M Moseman BL Mundt M Munk AC Okinaka RT Parson-Quintana B Reilly LP Richardson P Robinson DL Rubin E Saunders E Tapia R Tesmer JG Thayer N Thompson LS Tice H Ticknor LO Wills PL Brettin TS Gilna P 《Journal of bacteriology》2006,188(9):3382-3390
Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis are closely related gram-positive, spore-forming bacteria of the B. cereus sensu lato group. While independently derived strains of B. anthracis reveal conspicuous sequence homogeneity, environmental isolates of B. cereus and B. thuringiensis exhibit extensive genetic diversity. Here we report the sequencing and comparative analysis of the genomes of two members of the B. cereus group, B. thuringiensis 97-27 subsp. konkukian serotype H34, isolated from a necrotic human wound, and B. cereus E33L, which was isolated from a swab of a zebra carcass in Namibia. These two strains, when analyzed by amplified fragment length polymorphism within a collection of over 300 of B. cereus, B. thuringiensis, and B. anthracis isolates, appear closely related to B. anthracis. The B. cereus E33L isolate appears to be the nearest relative to B. anthracis identified thus far. Whole-genome sequencing of B. thuringiensis 97-27and B. cereus E33L was undertaken to identify shared and unique genes among these isolates in comparison to the genomes of pathogenic strains B. anthracis Ames and B. cereus G9241 and nonpathogenic strains B. cereus ATCC 10987 and B. cereus ATCC 14579. Comparison of these genomes revealed differences in terms of virulence, metabolic competence, structural components, and regulatory mechanisms. 相似文献
163.
Meredith H. Shaffer Yanping Huang Evann Corbo Gregory F. Wu Marielena Velez John K. Choi Ichiko Saotome Judy L. Cannon Andrea I. McClatchey Anne I. Sperling Jonathan S. Maltzman Paula M. Oliver Avinash Bhandoola Terri M. Laufer Janis K. Burkhardt 《PloS one》2010,5(8)
Background
Ezrin/radixin/moesin (ERM) proteins are highly homologous proteins that function to link cargo molecules to the actin cytoskeleton. Ezrin and moesin are both expressed in mature lymphocytes, where they play overlapping roles in cell signaling and polarity, but their role in lymphoid development has not been explored.Methodology/Principal Findings
We characterized ERM protein expression in lymphoid tissues and analyzed the requirement for ezrin expression in lymphoid development. In wildtype mice, we found that most cells in the spleen and thymus express both ezrin and moesin, but little radixin. ERM protein expression in the thymus was differentially regulated, such that ezrin expression was highest in immature thymocytes and diminished during T cell development. In contrast, moesin expression was low in early thymocytes and upregulated during T cell development. Mice bearing a germline deletion of ezrin exhibited profound defects in the size and cellularity of the spleen and thymus, abnormal thymic architecture, diminished hematopoiesis, and increased proportions of granulocytic precursors. Further analysis using fetal liver chimeras and thymic transplants showed that ezrin expression is dispensable in hematopoietic and stromal lineages, and that most of the defects in lymphoid development in ezrin−/− mice likely arise as a consequence of nutritional stress.Conclusions/Significance
We conclude that despite high expression in lymphoid precursor cells, ezrin is dispensable for lymphoid development, most likely due to redundancy with moesin. 相似文献164.
Bolze A Byun M McDonald D Morgan NV Abhyankar A Premkumar L Puel A Bacon CM Rieux-Laucat F Pang K Britland A Abel L Cant A Maher ER Riedl SJ Hambleton S Casanova JL 《American journal of human genetics》2010,87(6):873-881
Germline mutations in FASL and FAS impair Fas-dependent apoptosis and cause recessively or dominantly inherited autoimmune lymphoproliferative syndrome (ALPS). Patients with ALPS typically present with no other clinical phenotype. We investigated a large, consanguineous, multiplex kindred in which biological features of ALPS were found in the context of severe bacterial and viral disease, recurrent hepatopathy and encephalopathy, and cardiac malformations. By a combination of genome-wide linkage and whole-exome sequencing, we identified a homozygous missense mutation in FADD, encoding the Fas-associated death domain protein (FADD), in the patients. This FADD mutation decreases steady-state protein levels and impairs Fas-dependent apoptosis in vitro, accounting for biological ALPS phenotypes in vivo. It also impairs Fas-independent signaling pathways. The observed bacterial infections result partly from functional hyposplenism, and viral infections result from impaired interferon immunity. We describe here a complex clinical disorder, its genetic basis, and some of the key mechanisms underlying its pathogenesis. Our findings highlight the key role of FADD in Fas-dependent and Fas-independent signaling pathways in humans. 相似文献
165.
Ammanagi Avinash C. T. Shivasharana R. Krishnaveni Badiger Abhijeeth Ramaraj Vijayakumar 《Doklady biological sciences》2021,500(1):159-169
Doklady Biological Sciences - Melanin is a polyphenol or indolic dark brown to black pigment of macromolecules that has a variety of biological functions including UV defence, desiccation, and... 相似文献
166.
Avinash Mishra Satyanarayan Rao Aditya Mittal B. Jayaram 《Biochimica et Biophysica Acta - Proteins and Proteomics》2013,1834(8):1520-1531
Specification of the three dimensional structure of a protein from its amino acid sequence, also called a “Grand Challenge” problem, has eluded a solution for over six decades. A modestly successful strategy has evolved over the last couple of decades based on development of scoring functions (e.g. mimicking free energy) that can capture native or native-like structures from an ensemble of decoys generated as plausible candidates for the native structure. A scoring function must be fast enough in discriminating the native from unfolded/misfolded structures, and requires validation on a large data set(s) to generate sufficient confidence in the score. Here we develop a scoring function called pcSM that detects true native structure in the top 5 with 93% accuracy from an ensemble of candidate structures. If we eliminate the native from ensemble of decoys then pcSM is able to capture near native structure (RMSD < = 5 ?) in top 10 with 86% accuracy. The parameters considered in pcSM are a C-alpha Euclidean metric, secondary structural propensity, surface areas and an intramolecular energy function. pcSM has been tested on 415 systems consisting 142,698 decoys (public and CASP—largest reported hitherto in literature). The average rank for the native is 2.38, a significant improvement over that existing in literature. In-silico protein structure prediction requires robust scoring technique(s). Therefore, pcSM is easily amenable to integration into a successful protein structure prediction strategy. The tool is freely available at http://www.scfbio-iitd.res.in/software/pcsm.jsp. 相似文献
167.
Mukesh K. Malviya Anita Pandey Avinash Sharma Suresh C. Tiwari 《Annals of microbiology》2013,63(2):561-569
A total of 35 actinomycetes was isolated from soil samples collected after fire operations at agricultural sites under shifting cultivation in northeast India. More than one-half of these isolates were observed in viable but nonculturable (VBNC) state. Five isolates were always seen embedded with slimy bacteria during subculture; 11 morphologically distinct and cultivable isolates were subjected to characterization and identification. The isolates developed circular to irregular colonies of between 3 and 6 mm on tryptone yeast extract agar plates at 28 °C following 7 days of incubation. The isolates could survive at temperatures between 4 and 50 °C (optimum 28 °C), and pH 5–11 (optimum 8). The isolates varied in cell morphology, utilization of carbon sources, sensitivity to antibiotics, and salt tolerance. Based on 16S rRNA sequencing, the isolates revealed maximum similarity to the genus Streptomyces (9), and to Kitasatospora and Nocardia (1 each). Several isolates were found to be positive for production of lytic (chitinase and glucanase) and industrially important (amylase, lipase, and protease) enzymes. The occurrence of actinomycetes in VBNC state and embedded with bacteria was attributed to coping mechanisms associated with these organisms under stress (high temperature) conditions. The cultivable cultures extend the opportunity for further investigations on ecological resilience during fire operations. 相似文献
168.
V.S. Avinash Priyabrata Panigrahi C.G. Suresh Archana V. PundleSureshkumar Ramasamy 《Biochemical and biophysical research communications》2013
Penicillin V acylases (PVAs) and bile salt hydrolases (BSHs) have considerable sequence and structural similarity; however, they vary significantly in their substrate specificity. We have identified a PVA from a Gram-negative organism, Pectobacterium atrosepticum (PaPVA) that turned out to be a remote homolog of the PVAs and BSHs reported earlier. Even though the active site residues were conserved in PaPVA it showed high specificity towards penV and interestingly the penV acylase activity was inhibited by bile salts. Comparative modelling and docking studies were carried out to understand the structural differences of the binding site that confer this characteristic property. We show that PaPVA exhibits significant differences in structure, which are in contrast to those of known PVAs and such enzymes from Gram-negative bacteria require further investigation. 相似文献
169.
170.
Ji‐Yi Zhang Yi‐Ching Lee Ivone Torres‐Jerez Mingyi Wang Yanbin Yin Wen‐Chi Chou Ji He Hui Shen Avinash C. Srivastava Christa Pennacchio Erika Lindquist Jane Grimwood Jeremy Schmutz Ying Xu Manoj Sharma Rita Sharma Laura E. Bartley Pamela C. Ronald Malay C. Saha Richard A. Dixon Yuhong Tang Michael K. Udvardi 《The Plant journal : for cell and molecular biology》2013,74(1):160-173