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131.
DNA methylation changes in photoperiod-thermo-sensitive male sterile rice PA64S under two different conditions 总被引:1,自引:0,他引:1
Epigenetic modification can occur at a high frequency in crop plants and might generate phenotypic variation without changes in DNA sequences. DNA methylation is an important epigenetic modification that may contribute to environmentally-induced phenotypic variations by regulating gene expression. Rice Photoperiod-Thermo-Sensitive Genic Male Sterile (PTGMS) lines can transform from sterility to fertility under lower temperatures and short-day (SD) conditions during anther development. So far, little is known about the DNA methylation variation of PTGMS throughout the genome in rice. In this study, we investigated DNA cytosine methylation alterations in the young panicles of PTGMS line PA64S under two different conditions using methylation sensitive amplified polymorphism (MSAP) method. Compared with the DNA methylation level of PA64S under lower temperatures and SD conditions (fertility), higher methylation was observed in PA64S (sterility). The sequences of 25 differentially amplified fragments were successfully obtained and annotated. Three methylated fragments, which are homologous to D2, NAD7 and psaA, were confirmed by bisulfite sequencing and their expression levels were also evaluated by qPCR. Real time quantitative PCR analysis revealed that five of the six selected methylated genes were downregulated in PA64S (sterility). These results suggested that DNA methylation may be involved in the sterility–fertility transition of PA64S under two different environmental conditions. 相似文献
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Zhang Y Meng Q Jiang T Wang H Xie L Zhang R 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2003,135(1):43-54
Iron is one of the most important minor elements in the shell of bivalves. This study was designed to investigate the involvement of ferritin, the principal protein for iron storage, in shell formation. A novel ferritin cDNA from the pearl oyster (Pinctada fucata) was isolated and characterized. The ferritin cDNA encodes a 206 amino acid polypeptide, which shares high similarity with snail soma ferritin and the H-chains of mammalian ferritins. Oyster ferritin mRNA shows the highest level of expression in the mantle, the organ for shell formation. In situ hybridization analysis revealed that oyster ferritin mRNA is expressed at the highest level at the mantle fold, a region essential for metal accumulation and contributes to metal incorporation into the shell. Taken together, these results suggest that ferritin is involved in shell formation by iron storage. The identification and characterization of oyster ferritin also helps to further understand the structural and functional properties of molluscan ferritins. 相似文献
136.
一氧化氮增加常氧和缺氧豚鼠心室肌细胞持续性钠电流 总被引:7,自引:1,他引:7
运用全细胞膜片钳记录缺氧条件下豚鼠心室肌持续性钠电流(INa.P)的变化及施加药物对其的影响,以探讨 INa.P 的本质及缺氧增大 INa.P 的机制。结果显示:(1)在常氧条件下,一氧化氮(NO)前体 L- 精氨酸(L-Arg)和供体硝普钠(SNP)浓度依赖性地增大INa.P; (2)INa.P 随缺氧时间延长而增大, 缺氧15 min 后施加 NO 合酶(NOS)抑制剂L- 硝基精氨酸甲酯(L-NAME), 不能使增大的INa.P 明显回复[(1.344 ±0.320) vs (1.301 ±0.317) pA/pF, P>0.05, n=5]; (3)缺氧时含L-NAME 的灌流液可使INa.P 明显减小,与单纯缺氧相比有显著差异[(0.914 ± 0.263), n=5 vs (1.344 ± 0.320) pA/pF, n=6, P<0.05], 但仍比常氧条件下增大[(0.914 ±0.263) vs (0.497 ±0.149) pA/pF, P<0.05, n=5]; (4)还原剂1,4-二硫代苏糖醇(DTT)不但可使L-Arg 及缺氧后施加SNP 增大的 INa.P 回复[(1.449 ± 0.522) vs (0.414 ± 0.067) pA/pF, P<0.01, n = 6 和(0.436 ± 0.141) vs (1.786 ± 0.636) pA/pF,P<0.01, n=5],而且使正常的 INa.P 减小[(0.396 ± 0.057) pA/pF vs (0.442 ± 0.056) pA/pF, P<0.01, n=6]。本实验结果表明缺氧可增大心室肌细胞的INa.P, 其作用机制可能是缺氧时心肌产生的NO 通过氧化细胞膜上钠通道蛋白所致,正常INa.P 的产生 相似文献
137.
鸡减蛋综合征病毒(EDSV—76)末端前体蛋白的基因结构分析 总被引:1,自引:0,他引:1
从中国发病鸡群中分离的鸡减蛋综合征病毒弱毒株AA-2,经常规方法提取其病毒核酸后,组建了完整的限制性内切酶PstI及HingⅢ水解片段的基因文库,并对其中HindⅢ,-SacⅠ进行了序列测定。同源比较分析证明:其L链含编码病毒末端前体蛋白,容量为580个氨基酸残基的开放读码框架。 相似文献
138.
In super-resolution microscopy methods based on single-molecule switching, the rate of accumulating single-molecule activation events often limits the time resolution. Here we developed a sparse-signal recovery technique using compressed sensing to analyze images with highly overlapping fluorescent spots. This method allows an activated fluorophore density an order of magnitude higher than what conventional single-molecule fitting methods can handle. Using this method, we demonstrated imaging microtubule dynamics in living cells with a time resolution of 3 s. 相似文献
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Metabolic alteration of the N-glycan structure of a protein from patients with a heterozygous protein deficiency 总被引:1,自引:0,他引:1
Zhang F Bries AD Lang SC Wang Q Murhammer DW Weiler JM Linhardt RJ 《Biochimica et biophysica acta》2004,1739(1):43-49
Glycosylation, an important post-translation modification, could alter biological activity or influence the clearance rates of glycoproteins. We report here the first example of a heterozygous protein deficiency leading to metabolic alteration of N-glycan structures in residual secreted protein. Analysis of C1 esterase inhibitor (C1INH) glycans from normal individuals and patients with hereditary deficiency of C1INH demonstrated identical O-glycan structures but the N-glycans of patients with a heterozygous genetic deficiency were small, highly charged and lacked sialidase releasable N-acetylneuraminic acid. Structural studies indicate that the charge character of these aberrant N-glycan structures may result from the presence of mannose-6-phosphate residues. These residues might facilitate secretion of C1INH through an alternate lysosomal pathway, possibly serving as a compensatory mechanism to enhance plasma levels of C1INH in these deficient patients. 相似文献