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51.
Minhajuddin M Fazal F Bijli KM Amin MR Rahman A 《Journal of immunology (Baltimore, Md. : 1950)》2005,174(9):5823-5829
52.
Michael A Haq S Chen X Hsich E Cui L Walters B Shao Z Bhattacharya K Kilter H Huggins G Andreucci M Periasamy M Solomon RN Liao R Patten R Molkentin JD Force T 《The Journal of biological chemistry》2004,279(20):21383-21393
Glycogen synthase kinase (GSK) 3beta is a negative regulator of stress-induced cardiomyocyte hypertrophy. It is not clear, however, if GSK-3beta plays any role in regulating normal cardiac growth and cardiac function. Herein we report that a transgenic mouse expressing wild type GSK-3beta in the heart has a dramatic impairment of normal post-natal cardiomyocyte growth as well as markedly abnormal cardiac contractile function. The most striking phenotype, however, is grossly impaired diastolic relaxation, which leads to increased filling pressures of the left ventricle and massive atrial enlargement. This is due to profoundly abnormal calcium handling, leading to an inability to normalize cytosolic [Ca2+] in diastole. The alterations in calcium handling are due at least in part to direct down-regulation of the sarcoplasmic reticulum calcium ATPase (SERCA2a) by GSK-3beta, acting at the level of the SERCA2 promoter. These studies identify GSK-3beta as a regulator of normal growth of the heart and are the first of which we are aware, to demonstrate regulation of expression of SERCA2a, a critical determinant of diastolic function, by a cytosolic signaling pathway, the activity of which is dynamically modulated. De-regulation of GSK-3beta leads to severe systolic and diastolic dysfunction and progressive heart failure. Because down-regulation of SERCA2a plays a central role in the diastolic and systolic dysfunction of patients with heart failure, these findings have potential implications for the therapy of this disorder. 相似文献
53.
Lawson RJ Leys D Sutcliffe MJ Kemp CA Cheesman MR Smith SJ Clarkson J Smith WE Haq I Perkins JB Munro AW 《Biochemistry》2004,43(39):12410-12426
Cytochrome P450 BioI (CYP107H1) from Bacillus subtilis is involved in the early stages of biotin synthesis. Previous studies have indicated that BioI can hydroxylate fatty acids and may also perform an acyl bond cleavage reaction [Green, A. J., Rivers, S. L., Cheesman, M., Reid, G. A., Quaroni, L. G., Macdonald, I. D. G., Chapman, S. K., and Munro, A. W. (2001) J. Biol. Inorg. Chem. 6, 523-533. Stok, J. E., and De Voss, J. J. (2000) Arch. Biochem. Biophys. 384, 351-360]. Here we show novel binding features of P450 BioI--specifically that it binds steroids (including testosterone and progesterone) and polycyclic azole drugs with similar affinity to that for fatty acids (K(d) values in the range 0.1-160 microM). Sigmoidal binding curves for titration of BioI with azole drugs suggests a cooperative process in this case. BioI as isolated from Escherichia coli is in a mixed heme iron spin state. Alteration of the pH of the buffer system affects the heme iron spin-state equilibrium (higher pH increasing the low-spin content). Steroids containing a carbonyl group at the C(3) position induce a shift in heme iron spin-state equilibrium toward the low-spin form, whereas fatty acids produce a shift toward the high-spin form. Electron paramagnetic resonance (EPR) studies confirm the heme iron spin-state perturbation inferred from optical titrations with steroids and fatty acids. Potentiometric studies demonstrate that the heme iron reduction potential becomes progressively more positive as the proportion of high-spin heme iron increases (potential for low-spin BioI = -330 +/- 1 mV; for BioI as purified from E. coli (mixed-spin) = 228 +/- 2 mV; for palmitoleic acid-bound BioI = -199 +/- 2 mV). Extraction of bound substrate-like molecule from purified BioI indicates palmitic acid to be bound. Differential scanning calorimetry studies indicate that the BioI protein structure is stabilized by binding of steroids and bulky azole drugs, a result confirmed by resonance Raman studies and by analysis of disruption of BioI secondary and tertiary structure by the chaotrope guanidinium chloride. Molecular modeling of the BioI structure indicates that a disulfide bond is present between Cys250 and Cys275. Calorimetry shows that structural stability of the protein was altered by addition of the reductant dithiothreitol, suggesting that the disulfide is important to integrity of BioI structure. 相似文献
54.
Anwar KN Fazal F Malik AB Rahman A 《Journal of immunology (Baltimore, Md. : 1950)》2004,173(11):6965-6972
55.
Ihsan ul Haq Carlos Cáceres Peter Teal Christian Stauffer 《Journal of insect physiology》2010,56(11):1503-1509
The effect of access to dietary protein (P) and the topical application of a juvenile hormone analogue (methoprene (M)) on mating behaviour of male melon fly Bactrocera cucurbitae was assessed in the laboratory and in field cages. Age, dietary protein and methoprene application increased the mating success and influenced the mating behaviour. Treatment with methoprene (M+) to protein-deprived (P−) males had only a modest effect on the acceleration of sexual maturity, but application of methoprene (M+) to protein-fed (P+) males greatly accelerated sexual maturity. Protein diet (P+) increased mating success of males in comparison to protein-deprived (P−) males. Protein and methoprene have a synergistic effect on mating behaviour, since M + P+ treated males exhibit reduced mating latency and achieved higher mating in younger ages than methoprene and/or protein-deprived males. Copulation duration was correlated with nutritional status and M + P+ males copulated longer at the age of advanced sexual maturity than M − P+ males. Our results suggest that in this species with a lek mating system, females discriminate between the males based on their sexual signals, which were influenced by protein in the adult diet, methoprene application and age. The results are discussed in the light of mating competitiveness of precocious treated young males and their relevance to Sterile Insect Technique application against this pest species. 相似文献
56.
57.
Shazia Parveen Foziya Altaf Sumira Farooq Aehsan ul Haq Mohammad Lateef Lone Inayatullah Tahir 《Physiology and Molecular Biology of Plants》2021,27(7):1597
The present investigation primarily focussed on evaluating the efficacy of exogenous proline on the flower longevity of Dianthus chinensis L. Floral buds were harvested at the paint brush stage (i.e., a day prior to anthesis) and divided into 6 sets, with one set of buds (i.e., control) held in distilled water and rest of the 5 sets were supplemented with various concentrations of proline, viz., 10 mM, 20 mM, 30 mM, 40 mM and 50 mM. The application of proline at 40 mM concentration proved out to be most effective in improving the longevity of the flowers by about 4 days as compared to the control. The ameliorated longevity coincided with enhanced floral diameter, fresh mass, dry mass and water content. The flowers with delayed senescence also maintained higher soluble proteins, sugars and phenols. The results suggest that exogenous proline effectively alleviates oxidative stress in the petal tissue, as evident by a relatively lower maloendialdehyde content, which is manifested in the form of reduced lipid peroxidation (LPO). Reduced LPO was commensurate with increased membrane stability, quantified by membrane stability index. Moreover, the flowers with improved longevity exhibited a decline in lipoxygenase activity and significant augmentation of antioxidant enzymes superoxide dismutase, catalase and ascorbate peroxidase. 相似文献
58.
59.
Molecular Characterization of Mercury Resistant Bacteria Inhabiting Polluted Water Bodies of Different Geographical Locations in India 总被引:1,自引:0,他引:1
Mercury pollution is a major environmental problem that arises as a result of natural processes as well as from anthropogenic sources. In response to toxic mercury compounds, microbes have developed astonishing array of resistance systems to detoxify them. To address this challenge, this study was aimed in screening bacterial isolates for their tolerance against varied concentrations of phenylmercuric acetate. Mercury transformation by bacteria being sensitive to factors such as available carbon source, etc. that affect mer-mediated transformation, screened mercury tolerant bacteria were also studied for their tolerance to different antimicrobials and carbon sources, followed by identification using biochemical as well as 16S rRNA approach. Following identification, gene encoding organomercurial lyase catalyzing protonolytic cleavage of C-Hg bond of organic mercury was amplified using gene specific primers, cloned in pGEMT(?) easy vector and sequenced. Microbe-based approach using organomercurial lyase encoded by merB gene being potentially economic, provides foundation to facilitate genetic manipulation of this environmentally important enzyme to remove high concentrations of obstinate mercury using holistic, multifaceted approach for use in bioremediation through generation of transgenics or as catalyst for use in bioreactors. 相似文献
60.
Daniel J. Koslover Furqan M. Fazal Rachel A. MooneyRobert Landick Steven M. Block 《Journal of molecular biology》2012,423(5):664-676
Rho termination factor is an essential hexameric helicase responsible for terminating 20-50% of all mRNA synthesis in Escherichia coli. We used single-molecule force spectroscopy to investigate Rho-RNA binding interactions at the Rho utilization site of the λtR1 terminator. Our results are consistent with Rho complexes adopting two states: one that binds 57 ± 2 nt of RNA across all six of the Rho primary binding sites, and another that binds 85 ± 2 nt at the six primary sites plus a single secondary site situated at the center of the hexamer. The single-molecule data serve to establish that Rho translocates 5′ → 3′ toward RNA polymerase (RNAP) by a tethered-tracking mechanism, looping out the intervening RNA between the Rho utilization site and RNAP. These findings lead to a general model for Rho binding and translocation and establish a novel experimental approach that should facilitate additional single-molecule studies of RNA-binding proteins. 相似文献