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31.
32.
Background
A large number of papers have been published on analysis of microarray data with particular emphasis on normalization of data, detection of differentially expressed genes, clustering of genes and regulatory network. On other hand there are only few studies on relation between expression level and composition of nucleotide/protein sequence, using expression data. There is a need to understand why particular genes/proteins express more in particular conditions. In this study, we analyze 3468 genes of Saccharomyces cerevisiae obtained from Holstege et al., (1998) to understand the relationship between expression level and amino acid composition. 相似文献33.
Deinococcus radiodurans is a potent radiation resistant bacterium with immense potential in nuclear waste treatment. In this investigation, the translational and rotational dynamics of dilute suspensions of D. radiodurans cultured under controlled growth conditions was studied by the polarized and depolarized dynamic light-scattering (DLS) techniques. Additionally, confocal laser scanning microscopy was used for characterizing the cultured samples and also for identification of D. radiodurans dimer, tetramer, and multimer morphologies. The data obtained showed translational diffusion coefficients (DT) of 1.2 x 10(-9), 1.97 x 10(-9), and 2.12 x 10(-9) cm2 /s, corresponding to an average size of 3.61, 2.22, and 2.06 microm, respectively, for live multimer, tetramer, and dimer forms of D. radiodurans. Depolarized DLS experiments showed very slow rotational diffusion coefficients (DR) of 0.182/s for dimer and 0.098/s for tetramer morphologies. No measurable rotational diffusion was observed for multimer form. Polarized DLS measurements on live D. radiodurans confirmed that the bacterium is nonmotile in nature. The dynamics of the dead dimer and tetramer D. radiodurans were also studied using polarized and depolarized DLS experiments and compared with the dynamics of live species. The dead cells were slightly smaller in size when compared to the live cells. However, no additional information could be obtained for dead cells from the polarized and depolarized dynamic light-scattering studies. 相似文献
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Martino L Masini M Novelli M Beffy P Bugliani M Marselli L Masiello P Marchetti P De Tata V 《PloS one》2012,7(5):e36188
We have investigated the in vitro effects of increased levels of glucose and free fatty acids on autophagy activation in pancreatic beta cells. INS-1E cells and isolated rat and human pancreatic islets were incubated for various times (from 2 to 24 h) at different concentrations of glucose and/or palmitic acid. Then, cell survival was evaluated and autophagy activation was explored by using various biochemical and morphological techniques. In INS-1E cells as well as in rat and human islets, 0.5 and 1.0 mM palmitate markedly increased autophagic vacuole formation, whereas high glucose was ineffective alone and caused little additional change when combined with palmitate. Furthermore, LC3-II immunofluorescence co-localized with that of cathepsin D, a lysosomal marker, showing that the autophagic flux was not hampered in PA-treated cells. These effects were maintained up to 18-24 h incubation and were associated with a significant decline of cell survival correlated with both palmitate concentration and incubation time. Ultrastructural analysis showed that autophagy activation, as evidenced by the occurrence of many autophagic vacuoles in the cytoplasm of beta cells, was associated with a diffuse and remarkable swelling of the endoplasmic reticulum. Our results indicate that among the metabolic alterations typically associated with type 2 diabetes, high free fatty acids levels could play a role in the activation of autophagy in beta cells, through a mechanism that might involve the induction of endoplasmic reticulum stress. 相似文献
36.
M. S. Mary Judy Gopal B. V. R. Tata T. S. Rao S. Vincent 《World journal of microbiology & biotechnology》2008,24(11):2435-2442
Hexavalent chromium Cr(VI) is one of the dominant oxidation states of chromium that exist in the environment and is highly
toxic to all forms of life. In the present study, we employ a confocal laser scanning microscope (CLSM) and investigate the
effect of Cr(VI) on colony morphology of a Bacillus sp. isolated from soil exposed to tannery effluent. The colonies grown at chromium concentrations, control and 100 ppm are
found to be opaque and beyond 200 ppm the colonies were translucent thus exhibiting phase variation. CLSM studies on colonies
grown on control plates showed significant increase in height and in biovolume as a function of time whereas, the translucent
colonies showed very little change in height and biovolume corresponding to the colony growth. Exopolymeric substance (EPS)
content of translucent colonies was lesser than that of opaque colonies, indicating that EPS also plays a role in the observed
phenomenon of phase variation. Studies on the effect of Cr(VI) on spore formation showed that Cr(VI) concentrations up to
100 ppm favored spore formation, while concentrations beyond 100 ppm showed a steady decline in spore formation. 相似文献
37.
Chalmers JA Martino TA Tata N Ralph MR Sole MJ Belsham DD 《American journal of physiology. Regulatory, integrative and comparative physiology》2008,295(5):R1529-R1538
The circadian system in mammals is a hierarchy of oscillators throughout the organism that are coordinated by the circadian clock in the hypothalamic suprachiasmatic nucleus. Peripheral clocks act to integrate time-of-day information from neural or hormonal signals, regulating gene expression, and, subsequently, organ physiology. However, the mechanisms by which the central clock communicates with peripheral oscillators are not understood and are likely tissue specific. In this study, we establish a mouse vascular cell model suitable for investigations of these mechanisms at a molecular level. Using the immortalized vascular smooth muscle cell line Movas-1, we determined that these cells express the circadian clock machinery with robust rhythms in mRNA expression over a 36-h period after serum shock synchronization. Furthermore, norepinephrine and forskolin were able to synchronize circadian rhythms in bmal1. With synchronization, we observed cycling of specific genes, including the tissue inhibitor of metalloproteinase 1 and 3 (timp1, timp3), collagen 3a1 (col3a1), transgelin 1 (sm22alpha), and calponin 1 (cnn1). Diurnal expression of these genes was also found in vivo in mouse aortic tissue, using microarray and real-time RT-PCR analysis. Both of these revealed ultradian rhythms in genes similar to the cycling observed in Movas-1 in vitro. These findings highlight the cyclical nature of structurally important genes in the vasculature that is similar both in vivo and in vitro. This study establishes the Movas-1 cells as a novel cell model from which to further investigate the molecular mechanisms of clock regulation in the vasculature. 相似文献
38.
Tata Ringberg Lund-Larsen 《Acta zoologica》1977,58(2):61-63
The characteristic hypertrophying of the male reindeer neck muscles during the rutting period, which coincides with the rise in serum testosterone levels, is found to be accompanied by a significant decrease in lysosomal proteolytic activity of the neck muscle cells. Conversely, during the period of neck muscle involution following the rapid decline in serum testosterone after the rut, a marked increase in neck muscle proteolytic activity is found. These changes in lysosomal activity do not parallel the changes in feed consumption and nutritional stage of the animals during the rutting period. The lysosomal proteolytic activity of the male reindeer neck muscles thus may be, at least partly, under the control of sex steroid hormones. 相似文献
39.
Mammalian cardiac muscle is a remarkably heterogeneous tissue, as judged from enzyme analysis of tissue from different myocardial layers of the left ventricle free-wall. Its diversity results from a spectrum of fibres with different metabolic properties and different location across the wall, which may be especially suited to the local range of functional demands. 相似文献
40.