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排序方式: 共有328条查询结果,搜索用时 31 毫秒
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R A Rathod L J Bhagia G L Pandya V L Katagade D J Parikh B B Chatterjee 《European journal of applied physiology and occupational physiology》1987,56(1):58-63
A preliminary survey of the few units of the small-scale glass bangle industry in Firozabad, Agra District, Uttar Pradesh, indicated that the workers were exposed to severe degrees of heat stress during various operations in the manufacturing processes. A more detailed study in eight glass bangle units was therefore undertaken to make quantitative estimates of heat stress on exposed workers in the summer season. The thermal data collected confirmed that the heat stress on the workers was severe but measurement of certain physiological indicators revealed relatively low levels of strain amongst the exposed workers. The findings could be attributable to high degrees of acclimatization, but further observations in the field supplemented by studies on simulated exposures of volunteers in a climatic chamber seem to be warranted. 相似文献
3.
Harish Kumar Jayant B. Udgaonkar 《Protein science : a publication of the Protein Society》2021,30(4):785
Amyloid fibrillar aggregates isolated from the brains of patients with neurodegenerative diseases invariably have post‐translational modifications (PTMs). The roles that PTMs play in modulating the structures and polymorphism of amyloid aggregates, and hence their ability to catalyze the conversion of monomeric protein to their fibrillar structure is, however, poorly understood. This is particularly true in the case of tau aggregates, where specific folds of fibrillar tau have been implicated in specific tauopathies. Several PTMs, including acetylation at Lys 280, increase aggregation of tau in the brain, and increase neurodegeneration. In this study, tau‐K18 K280Q, in which the Lys 280 → Gln mutation is used to mimic acetylation at Lys 280, is shown, using HX‐MS measurements, to form fibrils with a structural core that is longer than that of tau‐K18 fibrils. Measurements of critical concentrations show that the binding affinity of monomeric tau‐K18 for its fibrillar counterpart is only marginally more than that of monomeric tau‐K18 K280Q for its fibrillar counterpart. Quantitative analysis of the kinetics of seeded aggregation, using a simple Michaelis–Menten‐like model, in which the monomer first binds and then undergoes conformational conversion to β‐strand, shows that the fibrils of tau‐K18 K280Q convert monomeric protein more slowly than do fibrils of tau‐K18. In contrast, monomeric tau‐K18 K280Q is converted faster to fibrils than is monomeric tau‐K18. Thus, the effect of Lys 280 acetylation on tau aggregate propagation in brain cells is expected to depend on the amount of acetylated tau present, and on whether the propagating seed is acetylated at Lys 280 or not. 相似文献
4.
Previously, we reported that incorporation of threo-beta-fluoroasparagine into cellular protein inhibits N-linked glycosylation. We now show that short synthetic peptides which contain N-acetyl-threo-beta-fluoroasparagine fail to undergo glycosylation in a cell-free system except at extremely high substrate concentrations. An N-benzoyl-threo-beta-fluoroasparagine-containing peptide has a 100-fold lower Vmax/Km than the analogous N-benzoyl-asparagine-containing peptide. Substitution of a fluorine for a hydrogen on the beta-carbon of asparagine weakens the ability of the peptide to bind the oligosaccharyltransferase. A 100-fold excess of acetyl-threo-beta-fluoroasparaginyl-leucyl-threonine methylamide over acetyl-asparaginyl-leucyl-threonine methylamide inhibited glycosylation of the latter peptide by less than 10%. Both threo-beta-fluoroasparagine and erythro-beta-fluoroasparagine-containing peptides are glycosylated at the same rate. Glycofluoropeptides generated from beta-fluoroasparagine-containing peptides were N-glycosylated. These cell-free studies with synthetic fluoropeptides suggest that incorporation of beta-fluoroasparagine into cellular protein inhibits N-linked glycosylation by rendering protein substrates ineffective for glycosylation. In the course of this work, we also demonstrate that the N-linked glycosylating enzyme acts only on L-asparagine-containing peptides and not on D-asparagine peptides. 相似文献
5.
Benoît F. Morel Meghan A. Burke Jayant Kalagnanam Susan A. McCarthy David J. Tweardy Penelope A. Morel 《Bulletin of mathematical biology》1996,58(3):569-594
The cytokines are the information superhighway of the immune system. They are an important component of the integrated behavior
of the system. In order to be able to have a good understanding of the immune system, we must be able to model the effect
of cytokines and their combined effect. This work is a step in that direction. We study the combined effect of two cytokines:
interleukin-2 (IL-2) and interleukin-4 (IL-4) on some cells of the immune system.
Interleukin-2 and interleukin-4 are important growth and differentiation factors for B and T cells. Interleukin-4 antagonizes
the effect of interleukin-2 on B cells and some T cells while it synergizes with interleukin-2 on other T cells. We build
a mathematical model of the interaction of both cytokines on T and B cells as a building block toward a model of the Th1/Th2
cross-regulation. The response of a given cell to the combination of interleukin-2 and interleukin-4 is shown to involve competing
dynamical effects which can lead to either antagnostic or synergistic combined effect.
Author to whom correspondence should be addressed at Department of Engineering and Public Policy. Work supported by NIH grant
nv: Ai31427. 相似文献
6.
Baljinder Singh Devinder Dhawan Bakhshi Chand Pralhad Chand Mangal 《Biological trace element research》1994,40(3):287-293
The impact of lead as an environmental pollutant on the I-131 uptake and retention in rat thyroid was assayed alone and in combination with lithium treatment. Lead treatment significantly stimulated the 2- and 24-h uptake of I-131 in the thyroid, and the 24-h uptake showed the maximum stimulation after 3 mo of lead treatment. On the contrary, lithium supplementation reduced the uptake significantly and the maximum decrease was noticed after 2 mo of lithium administration. Further, simultaneous lead and lithium treatment resulted in more pronounced increase in the uptake of I-131 by the thyroid, which was maximum after 3 mo of combined treatment. The thyroidal biological half-life of I-131 (T biol) was found to be increased significantly following lead and lithium treatments when given separately. Interestingly, combined lead and lithium treatment given up to 2 mo further prolonged theT biol of I-131, thus reflecting its increased retention. 相似文献
7.
Butler Michael J. Aphale Jayant S. DiZonno Michele A. Krygsman Phyllis Walczyk Eva Malek Lawrence T. 《Journal of industrial microbiology & biotechnology》1994,13(1):24-29
Summary We have investigated the aminopeptidase activities present inStreptomyces lividans strains. The majority of these activities proved to be intracellular with multiple active species. Two aminopeptidase P genes were identified to be responsible for the ability to hydrolyze amino terminal peptide bonds adjacent to proline residues. Two other broad spectrum aminopeptidases were found to display homology at both the DNA and protein levels. One showed significant homology to PepN proteins, particularly around the putative zinc-binding residues which are important for catalysis. The second broad spectrum activity was not analyzed in detail but showed a different spectrum of substrate specificity to that of PepN. 相似文献
8.
A new variant of hereditary hemolytic anemia in a family due to high adenosine triphosphate (ATP) is reported. The increase in ATP levels varied from 83 to 105% in the family members. Low 2,3-diphosphoglycerate levels and low 2,3-diphosphoglyceromutase activity were observed in three family members, with normal glucose-6-phosphate dehydrogenase and pyruvate kinase activity. 相似文献
9.
Nury M. Steuerwald David M. Foureau H. James Norton Jie Zhou Judith C. Parsons Naga Chalasani Robert J. Fontana Paul B. Watkins William M. Lee K. Rajender Reddy Andrew Stolz Jayant Talwalkar Timothy Davern Dhanonjoy Saha Lauren N. Bell Huiman Barnhart Jiezhun Gu Jose Serrano Herbert L. Bonkovsky 《PloS one》2013,8(12)
Drug-induced liver injury (DILI) is the most common cause of acute liver failure in the United-States. The aim of the study was to describe serum immune profiles associated with acute DILI, to investigate whether there are profiles associated with clinical features or types of DILI and/or with prognosis, and to assess temporal changes in levels. Twenty-seven immune analytes were measured in the sera of 78 DILI subjects in the Drug-Induced Liver Injury Network (DILIN) and compared with 40 healthy controls. Immune analytes (14 cytokines, 7 chemokines and 6 growth factors) were measured by BioPlex multiplex ELISA at DILI onset and after 6 months. A modeling process utilizing immune principles was used to select a final set of variables among 27 immune analytes and several additional clinical lab values for prediction of early death (within 6 months of DILI onset). Nineteen of the 27 immune analytes were differentially expressed among healthy control, DILI onset and 6-month cohorts. Disparate patterns of immune responses, especially innate and adaptive cellular (mostly TH17) immunity were evident. Low values of four immune analytes (IL-9, IL-17, PDGF-bb and RANTES) and serum albumin are predictive of early death [PPV = 88% (95% CI, 65%-100%), NPV = 97% (95% CI, 93%-100%), accuracy = 96% (95% CI, 92%-100%)].
Conclusions
Acute DILI is associated with robust and varying immune responses. High levels of expression of cytokines associated with innate immunity are associated with a poor prognosis, whereas high levels of expression of adaptive cytokines are associated with good long-term prognosis and eventual recovery. Serum immune analyte profiles at DILI onset appear to be of prognostic, and perhaps, diagnostic significance. 相似文献10.
Jayant Pralhad Rathod Gunjan Prakash Reena Pandit Arvind M. Lali 《Photosynthesis research》2013,118(1-2):141-146
Parachlorella kessleri is a unicellular alga which grows in fresh as well as marine water and is commercially important as biomass/lipid feedstock and in bioremediation. The present study describes the successful transformation of marine P. kessleri with the help of Agrobacterium tumefaciens. Transformed marine P. kessleri was able to tolerate more than 10 mg l?1 hygromycin concentration. Co-cultivation conditions were modulated to allow the simultaneous growth of both marine P. kessleri and A. tumefaciens. For co-cultivation, P. kessleri was shifted from Walne’s to tris acetate phosphate medium to reduce the antibiotic requirement during selection. In the present study, the transfer of T-DNA was successful without using acetosyringone. Biochemical and genetic analyses were performed for expression of transgenes by GUS assay and PCR in transformants. Establishment of this protocol would be useful in further genetic modification of oil-bearing Parachlorella species. 相似文献