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61.
Dhivya Subramanian Junqi Huang Mayalagu Sevugan Robert C. Robinson Mohan K. Balasubramanian Xie Tang 《Genetics》2013,194(2):435-446
Actin is a key cytoskeletal protein with multiple roles in cellular processes such as polarized growth, cytokinesis, endocytosis, and cell migration. Actin is present in all eukaryotes as highly dynamic filamentous structures, such as linear cables and branched filaments. Detailed investigation of the molecular role of actin in various processes has been hampered due to the multifunctionality of the protein and the lack of alleles defective in specific processes. The actin cytoskeleton of the fission yeast, Schizosaccharomyces pombe, has been extensively characterized and contains structures analogous to those in other cell types. In this study, primarily with the view to uncover actin function in cytokinesis, we generated a large bank of fission yeast actin mutants that affect the organization of distinct actin structures and/or discrete physiological functions of actin. Our screen identified 17 mutants with specific defects in cytokinesis. Some of these cytokinesis mutants helped in dissecting the function of specific actin structures during ring assembly. Further genetic analysis of some of these actin mutants revealed multiple genetic interactions with mutants previously known to affect the actomyosin ring assembly. We also characterize a mutant allele of actin that is suppressed upon overexpression of Cdc8p-tropomyosin, underscoring the utility of this mutant bank. Another 22 mutant alleles, defective in polarized growth and/or other functions of actin obtained from this screen, are also described in this article. This mutant bank should be a valuable resource to study the physiological and biochemical functions of actin. 相似文献
62.
Isolation and characterization of Aspergillus sp. for the production of extracellular polysaccharides by response surface methodology 总被引:1,自引:0,他引:1
Balamuralikrishnan Balasubramanian Soundharrajan Ilavenil Paul Agastian Ki Choon Choi 《Saudi Journal of Biological Sciences》2019,26(3):449-454
In this study, Aspergillus sp. was isolated for the production of extracellular polysaccharide. The process parameters were initially optimized by traditional methods. The cheap substrate, wheat bran was used for the production of extracellular polysaccharide in solid state fermentation. Supplementation of (1%, w/w) maltose, gelatin enhanced EPS production (5.36?mg/g). The salts such as, Cu2+ (4.9?mg/g), Ca2+ (3.5?mg/g), Zn2+ (2.9?mg/g), Mn2+ (3.4?mg/g) and Mg2+ (1.8?mg/g) stimulated EPS production. In two level full factorial experimental designs, the EPS yield varied from 3.18 to 11.65?mg/g wheat bran substrate with various combinations of the components supplemented with wheat bran substrate. Among these selected factors in central composite design, maltose significantly influenced on extracellular polysaccharide production. 相似文献
63.
64.
The Rox1 repressor of the Saccharomyces cerevisiae hypoxic genes is a specific DNA-binding protein with a high-mobility-group motif. 总被引:6,自引:5,他引:6 下载免费PDF全文
The ROX1 gene encodes a repressor of the hypoxic functions of the yeast Saccharomyces cerevisiae. The DNA sequence of the gene was determined and found to encode a protein of 368 amino acids. The amino-terminal third of the protein contains a high-mobility-group motif characteristic of DNA-binding proteins. To determine whether the Rox1 repressor bound DNA, the gene was expressed in Escherichia coli cells as a fusion to the maltose-binding protein and this fusion was partially purified by amylose affinity chromatography. By using a gel retardation assay, both the fusion protein and Rox1 itself were found to bind specifically to a synthetic 32-bp DNA containing the hypoxic consensus sequence. We assessed the role of the general repressor Ssn6 in ANB1 repression. An ANB1-lacZ fusion was expressed constitutively in an ssn6 deletion strain, and deletion of the Rox1 binding sites in the ANB1 upstream region did not increase the level of derepression, suggesting that Ssn6 exerts its effect through Rox1. Finally, ROX1 was mapped to yeast chromosome XVI, near the ARO7-OSM2 locus. 相似文献
65.
B Senthilkumaran M M Aruldhas R C Udhayakumar P Govindarajulu 《Indian journal of experimental biology》1991,29(3):205-207
Impact of thyroidectomy (hypothyroidism) on few glycosidases was studied in the seminal vesicles of young albino rats. Thyroidectomy was performed at 30 days post partum. Seminal vesicular beta-D-glucosidase, beta-D-galactosidase, and N-acetyl-beta-D-galactosaminidase exhibited a similar response of decreased activities under short- (30 days) and long-term (60 days) hypothyroid conditions. On the other hand, N-acetyl-beta-D-glucosaminidase registered a temporal biphasic response of increased and decreased activities in the seminal vesicles of rats subjected to short- and long-term hypothyroidism, respectively. The data obtained in the present study suggest that thyroid hormones have specific influences on different glycosidases in the seminal vesicles of rats and euthyroid status is essential for the maintenance of normal activities of these enzymes. 相似文献
66.
67.
The influence of seed and root exudations on the rhizosphere effect ofSorghum vulgare andCrotalaria juncea was examined. While the quantitative occurrence of certain morphological and physiological groups of bacteria on the seeds
and rhizospheres of the two plant species differed, there were similarities in the occurrence of certain physiological and
nutritional groups of bacteria on the seed as well as on the rhizosphere. The occurrence of some genera of fungi on the seeds
and in the rhizosphere indicated the influence of both seeds and root exudations on the rhizosphere effect. Increase in root
exudations of amino acids and sugars correlated with a concomitant increase in microbial activity in the rhizosphere on the
15th day of growth in both plant species but there was a delayed effect of the exuded chemicals on the rhizosphere microflora
after 30 d of plant growth.
Based on the Ph.D. thesis of the first author submitted to the University of Agricultural Sciences, Bangalore. 相似文献
68.
69.
Krishnamurthy B Mariana L Gellert SA Colman PG Harrison LC Lew AM Santamaria P Thomas HE Kay TW 《Journal of immunology (Baltimore, Md. : 1950)》2008,180(7):4458-4464
T cells specific for proinsulin and islet-specific glucose-6-phosphatase catalytic subunit related protein (IGRP) induce diabetes in nonobese diabetic (NOD) mice. TCR transgenic mice with CD8(+) T cells specific for IGRP(206-214) (NOD8.3 mice) develop accelerated diabetes that requires CD4(+) T cell help. We previously showed that immune responses against proinsulin are necessary for IGRP(206-214)-specific CD8(+) T cells to expand. In this study, we show that diabetes development is dramatically reduced in NOD8.3 mice crossed to NOD mice tolerant to proinsulin (NOD-PI mice). This indicates that immunity to proinsulin is even required in the great majority of NOD8.3 mice that have a pre-existing repertoire of IGRP(206-214)-specific cells. However, protection from diabetes could be overcome by inducing islet inflammation either by a single dose of streptozotocin or anti-CD40 agonist Ab treatment. This suggests that islet inflammation can substitute for proinsulin-specific CD4(+) T cell help to activate IGRP(206-214)-specific T cells. 相似文献
70.
Nagarathnam B Kannan S Dharnidharka V Balakrishnan V Archunan G Sowdhamini R 《Bioinformation》2011,7(1):15-20
G-protein coupled receptors (GPCRs) belong to biologically important and functionally diverse and largest super family of membrane proteins. GPCRs retain a characteristic membrane topology of seven alpha helices with three intracellular, three extracellular loops and flanking N' and C' terminal residues. Subtle differences do exist in the helix boundaries (TM-domain), loop lengths, sequence features such as conserved motifs, and substituting amino acid patterns and their physiochemical properties amongst these sequences (clusters) at intra-genomic and inter-genomic level (please re-phrase into 2 statements for clarity). In the current study, we employ prediction of helix boundaries and scores derived from amino acid substitution exchange matrices to identify the conserved amino acid residues (motifs) as consensus in aligned set of homologous GPCR sequences. Co-clustered GPCRs from human and other genomes, organized as 32 clusters, were employed to study the amino acid conservation patterns and species-specific or cluster-specific motifs. Critical analysis on sequence composition and properties provide clues to connect functional relevance within and across genome for vast practical applications such as design of mutations and understanding of disease-causing genetic abnormalities. 相似文献