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排序方式: 共有248条查询结果,搜索用时 15 毫秒
31.
Gardner MK Haase J Mythreye K Molk JN Anderson M Joglekar AP O'Toole ET Winey M Salmon ED Odde DJ Bloom K 《The Journal of cell biology》2008,180(1):91-100
In budding yeast, the mitotic spindle is comprised of 32 kinetochore microtubules (kMTs) and ~8 interpolar MTs (ipMTs). Upon anaphase onset, kMTs shorten to the pole, whereas ipMTs increase in length. Overlapping MTs are responsible for the maintenance of spindle integrity during anaphase. To dissect the requirements for anaphase spindle stability, we introduced a conditionally functional dicentric chromosome into yeast. When centromeres from the same sister chromatid attach to opposite poles, anaphase spindle elongation is delayed and a DNA breakage-fusion-bridge cycle ensues that is dependent on DNA repair proteins. We find that cell survival after dicentric chromosome activation requires the MT-binding proteins Kar3p, Bim1p, and Ase1p. In their absence, anaphase spindles are prone to collapse and buckle in the presence of a dicentric chromosome. Our analysis reveals the importance of Bim1p in maintaining a stable ipMT overlap zone by promoting polymerization of ipMTs during anaphase, whereas Kar3p contributes to spindle stability by cross-linking spindle MTs. 相似文献
32.
Crossovers (COs) play a critical role in ensuring proper alignment and segregation of homologous chromosomes during meiosis. How the cell balances recombination between CO vs. noncrossover (NCO) outcomes is not completely understood. Further lacking is what constrains the extent of DNA repair such that multiple events do not arise from a single double-strand break (DSB). Here, by interpreting signatures that result from recombination genome-wide, we find that synaptonemal complex proteins promote crossing over in distinct ways. Our results suggest that Zip3 (RNF212) promotes biased cutting of the double Holliday-junction (dHJ) intermediate whereas surprisingly Msh4 does not. Moreover, detailed examination of conversion tracts in sgs1 and mms4-md mutants reveal distinct aberrant recombination events involving multiple chromatid invasions. In sgs1 mutants, these multiple invasions are generally multichromatid involving 3–4 chromatids; in mms4-md mutants the multiple invasions preferentially resolve into one or two chromatids. Our analysis suggests that Mus81/Mms4 (Eme1), rather than just being a minor resolvase for COs is crucial for both COs and NCOs in preventing chromosome entanglements by removing 3′- flaps to promote second-end capture. Together our results force a reevaluation of how key recombination enzymes collaborate to specify the outcome of meiotic DNA repair. 相似文献
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Anupama A. Sharan Ashwini N. Nikam Abdul Jaleel Vaijayanti A. Tamhane Srinivasa P. Rao 《Tropical plant biology》2018,11(1-2):78-91
Sorghum (Sorghum bicolor L. Moench) is a rapidly emerging high biomass feedstock for bioethanol and lignocellulosic biomass production. The robust varietal germplasm of sorghum and its completed genome sequence provide the necessary genetic and molecular tools to study and engineer the biotic/abiotic stress tolerance. Traditional proteomics approaches for outlining the sorghum proteome have many limitations like, demand for high protein amounts, reproducibility and identification of only few differential proteins. In this study, we report a gel-free, quantitative proteomic method for in-depth coverage of the sorghum proteome. This novel method combining phenol extraction and methanol chloroform precipitation gives high total protein yields for both mature sorghum root and leaf tissues. We demonstrate successful application of this method in comparing proteomes of contrasting cultivars of sorghum, at two different phenological stages. Protein identification and relative quantification analyses were performed by a label-free liquid chromatography tandem mass spectrometry (LC/MS-MS) analyses. Several unique proteins were identified respectively from sorghum tissues, specifically 271 from leaf and 774 from root tissues, with 193 proteins common in both tissues. Using gene ontology analysis, the differential proteins identified were finely corroborated with their leaf/root tissue specific functions. This method of protein extraction and analysis would contribute substantially to generate in-depth differential protein data in sorghum as well as related species. It would also increase the repertoire of methods uniquely suited for gel-free plant proteomics that are increasingly being developed for studying abiotic and biotic stress responses. 相似文献
38.
Sampa Santra Ashwini K. Sood Swapan K. Ghosh 《Cancer immunology, immunotherapy : CII》1999,48(8):421-429
Active specific immunotherapy of neoplastic diseases is an elusive goal. Using a murine B lymphoma 2C3, we showed that vaccination
with the killed tumor cells effectively induces protective immunity and a cytotoxic T cell (CTL) response. Similar protection,
however, is rarely observed in mice bearing live tumor cells. These animals usually succumb to the progressively growing tumor.
In this study, we inquired whether the splenic CTL induced during tumor progression in mice differ from those evoked by the
killed tumor cells. Here we demonstrate that the CTL generated following vaccination are significantly different from those
induced in the tumor-bearing hosts. Adding to the complexity, the CTL from the early tumor bearers also differ significantly
from those induced at the late stages. These differences are based on their cytotoxic activity, MHC allele specificity, mitogen
responsiveness, cytokine secretion profile and T cell receptor Vβ gene expression. The results clearly indicate that passive
immunization with killed tumor is most effective, possibly because the CTL induced are not subject to the same regulatory
pressure as those induced during active tumor growth. This decreasing effectiveness of CTL could be due to greater variability
in antigenic stimulus, less involvement of innate immunity, changes in cytokine milieu and/or costimulatory factors.
Received: 5 February 1999 / Accepted: 22 June 1999 相似文献
39.
Ashwini Jadhav Bhagyashree Bansode Datta Phule Amruta Shelar Rajendra Patil Wasudev Gade Kiran Kharat Sankunny Mohan Karuppayil 《World journal of microbiology & biotechnology》2017,33(5):96
Fluoroquinolines are broad spectrum fourth generation antibiotics. Some of the Fluoroquinolines exhibit antifungal activity. We are reporting the potential mechanism of action of a fluoroquinoline antibiotic, moxifloxacin on the growth, morphogenesis and biofilm formation of the human pathogen Candida albicans. Moxifloxacin was found to be Candidacidal in nature. Moxifloxacin seems to inhibit the yeast to Hyphal morphogenesis by affecting signaling pathways. It arrested the cell cycle of C. albicans at S phase. Docking of moxifloxacin with predicted structure of C. albicans DNA Topoisomerase II suggests that moxifloxacin may bind and inhibit the activity of DNA Topoisomerase II in C. albicans. Moxifloxacin could be used as a dual purpose antibiotic for treating mixed infections caused by bacteria as well as C. albicans. In addition chances of developing moxifloxacin resistance in C. albicans are less considering the fact that moxifloxacin may target multiple steps in yeast to hyphal transition in C. albicans. 相似文献
40.
Complex biological systems exhibit a property of robustness at all levels of organization. Through different mechanisms, the
system tries to sustain stress such as due to starvation or drug exposure. To explore whether reconfiguration of the metabolic
networks is used as a means to achieve robustness, we have studied possible metabolic adjustments in Mtb upon exposure to
isoniazid (INH), a front-line clinical drug. The redundancy in the genome of M. tuberculosis (Mtb) makes it an attractive system to explore if alternate routes of metabolism exist in the bacterium. While the mechanism
of action of INH is well studied, its effect on the overall metabolism is not well characterized. Using flux balance analysis,
inhibiting the fluxes flowing through the reactions catalyzed by Rv1484, the target of INH, significantly changes the overall
flux profiles. At the pathway level, activation or inactivation of certain pathways distant from the target pathway, are seen.
Metabolites such as NADPH are shown to reduce drastically, while fatty acids tend to accumulate. The overall biomass also
decreases with increasing inhibition levels. Inhibition studies, pathway level clustering and comparison of the flux profiles
with the gene expression data indicate the activation of folate metabolism, ubiquinone metabolism, and metabolism of certain
amino acids. This analysis provides insights useful for target identification and designing strategies for combination therapy.
Insights gained about the role of individual components of a system and their interactions will also provide a basis for reconstruction
of whole systems through synthetic biology approaches. 相似文献