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He Lijun Zhang Jinsha He Chengyun Zhao Boyang Chen Weizhong Patil Sunil R. 《Molecular and cellular biochemistry》2021,476(3):1599-1603
Molecular and Cellular Biochemistry - DNA hydroxymethylation plays a very important role in some biological processes, such as DNA methylation process. In addition, its presence can also cause some... 相似文献
3.
S. Kumar Sunil Kumar S. P. Negi J. K. Kanwar 《In vitro cellular & developmental biology. Plant》2008,44(6):474-479
Callus cultures derived from leaf segments of chrysanthemum cultivar ‘Snow Ball’ which was susceptible to Septoria obesa were successfully used for in vitro selection for resistance to this pathogenic fungus. Resistant cell lines were selected by culturing callus on growth medium
containing various concentrations of S. obesa filtrate. Resistant calluses obtained after two cycles (30 d each cycle) of selection were used for plant regeneration. About
30% of the plants regenerated from the resistant calluses and 70–80% of the plants raised from cuttings had acquired considerable
resistance against the pathogen in the field. No phenotypic variation was observed in the selected regenerates. 相似文献
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Sunil K Pandya 《BMJ (Clinical research ed.)》1990,300(6723):529-530
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Tabassum Naqvi Trang T Duong Gihan Hashem Momotoshi Shiga Qin Zhang Sunil Kapila 《Arthritis research & therapy》2004,7(1):R1
Diseases of specific fibrocartilaginous joints are especially common in women of reproductive age, suggesting that female
hormones contribute to their etiopathogenesis. Previously, we showed that relaxin dose-dependently induces matrix metalloproteinase
(MMP) expression in isolated joint fibrocartilaginous cells. Here we determined the effects of relaxin with or without β-estradiol
on the modulation of MMPs in joint fibrocartilaginous explants, and assessed the contribution of these proteinases to the
loss of collagen and glycosaminoglycan (GAG) in this tissue. Fibrocartilaginous discs from temporomandibular joints of female
rabbits were cultured in medium alone or in medium containing relaxin (0.1 ng/ml) or β-estradiol (20 ng/ml) or relaxin plus
β-estradiol. Additional experiments were done in the presence of the MMP inhibitor GM6001 or its control analog. After 48
hours of culture, the medium was assayed for MMPs and the discs were analyzed for collagen and GAG concentrations. Relaxin
and β-estradiol plus relaxin induced the MMPs collagenase-1 and stromelysin-1 in fibrocartilaginous explants – a finding similar
to that which we observed in pubic symphysis fibrocartilage, but not in articular cartilage explants. The induction of these
proteinases by relaxin or β-estradiol plus relaxin was accompanied by a loss of GAGs and collagen in joint fibrocartilage.
None of the hormone treatments altered the synthesis of GAGs, suggesting that the loss of this matrix molecule probably resulted
from increased matrix degradation. Indeed, fibrocartilaginous explants cultured in the presence of GM6001 showed an inhibition
of relaxin-induced and β-estradiol plus relaxin-induced collagenase and stromelysin activities to control baseline levels
that were accompanied by the maintenance of collagen or GAG content at control levels. These findings show for the first time
that relaxin has degradative effects on non-reproductive synovial joint fibrocartilaginous tissue and provide evidence for
a link between relaxin, MMPs, and matrix degradation. 相似文献
10.
Mitogen-activated 70K S6 kinase. Identification of in vitro 40 S ribosomal S6 phosphorylation sites 总被引:9,自引:0,他引:9
S Ferrari H R Bandi J Hofsteenge B M Bussian G Thomas 《The Journal of biological chemistry》1991,266(33):22770-22775
Recently we purified and cloned the mitogen/oncogene-activated Mr 70,000 (70K) S6 kinase from the livers of rats treated with cycloheximide (Kozma, S. C., Lane, H. A., Ferrari, S., Luther, H., Siegmann, M., and Thomas, G. (1989) EMBO J. 8, 4125-4132; Kozma, S. C., Ferrari, S., Bassand, P., Siegmann, M., Totty, N., and Thomas, G. (1990) Proc. Natl. Acad. Sci. U. S. A. 87, 7365-7369). Prior to determining the ability of this kinase to phosphorylate the same sites observed in S6 in vivo, we established the effects of different cations and autophosphorylation on kinase activity. The results show that the 70K S6 kinase is dependent on Mg2+ for activity and that this requirement cannot be substituted for by Mn2+. Furthermore, 50-fold lower concentrations of Mn2+ block the effect of Mg2+ on the kinase. This effect is not limited to Mn2+ but can be substituted for by a number of cations, with Zn2+ being the most potent inhibitor, IC50 approximately 2 microM. In the presence of optimum Mg2+ concentrations the enzyme incorporates an average of 1.2 mol of phosphate/mol of kinase and an average of 3.7 mol of phosphate/mol of S6. The autophosphorylation reaction appears to be intramolecular and leads to a 25% reduction in kinase activity toward S6. In the case of S6 all of the sites of phosphorylation are found to reside in a 19-amino acid peptide at the carboxyl end of the protein. Four of these sites have been identified as Ser235, Ser236, Ser240, and Ser244, equivalent to four of the five sites previously observed in vivo (Krieg, J., Hofsteenge, J., and Thomas, G. (1988) J. Biol. Chem. 263, 11473-11477). A fifth mole of phosphate is incorporated at low stoichiometry into the peptide, but the amino acid which is phosphorylated cannot be unequivocally assigned. The low level of phosphorylation of the fifth site in vitro is discussed with regard to known results and to a potential three-dimensional model for the carboxyl terminus of S6. 相似文献