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991.
Ia Meldra?s I V Lebedeva A Ia Druka M G Ivanovskaia Z A Shabarova T I Gurinovich K A Birznieks V G Keks A A Ze?daka 《Molekuliarnaia biologiia》1992,26(3):540-545
A 26 base long oligodeoxyribonucleotide complementary to a common RNA sequence of potato spindle tuber viroid (PSTV) and chrysantemum stunt viroid (CSV) was synthesized. The 3'-end biotinylated one was used for the detection of PSTV and CSV RNA immobilized on nitrocellulose filters by nucleic acid hybridization. Visualization of hybridization results was performed by two ways, either by streptavidin-alkaline phosphatase conjugate or streptavidine and biotinylated alkaline phosphatase. It was possible to detect 0.65 ng of purified CSV and PSTV RNA. The suggested system of viroid diseases detection can be used by agricultural and horticultural enterprises. 相似文献
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993.
浙江及邻近地区蛇足石杉依存环境的初步研究 总被引:1,自引:0,他引:1
对浙江及邻近地区产的蛇足石杉(Huperzia serratct)7个种群的自然环境进行野外观察,测定了土壤含水量、电导率、有机质含量、pH值,植株和土壤中K、Ca、Mg、Fe、Zn、Cu、Mn、Na、A1、Pb、Cd 11种元素的含量,以及植株中石杉碱甲(HupA)含量。结果表明,蛇足石杉种群多分布于海拔350-1700m的山地密林下或沟谷阴湿土中,郁闭度、年均降雨量、空气相对湿度均较大:环境中土壤含水量为10%-30%,pH值4.57—5.31,电导率0.061—0.385mscm^-1,有机质含量6.18%-9.75%;蛇足石杉对K、Ca、Zn和Na的需要程度较高,对Pb、Cu、Cd3种重金属元素的富集能力较强,在人工栽培中应注意协调各元素的合理配给:蛇足石杉较适宜生长的环境条件为:土壤电导率以及pH值相对较低;郁闭度高,年均降雨量和空气相对湿度较大。基于土壤理化性质,对7个种群分布点进行除趋势对应分析,表明石杉碱甲含量高的磐安种群分布点具有特殊性,提示环境条件对蛇足石杉中HupA含量有较大的影响。 相似文献
994.
Phylogenetic Articulation of Uric Acid Evolution in Mammals and How It Informs a Therapeutic Uricase
The role of uric acid during primate evolution has remained elusive ever since it was discovered over 100 years ago that humans have unusually high levels of the small molecule in our serum. It has been difficult to generate a neutral or adaptive explanation in part because the uricase enzyme evolved to become a pseudogene in apes thus masking typical signals of sequence evolution. Adding to the difficulty is a lack of clarity on the functional role of uric acid in apes. One popular hypothesis proposes that uric acid is a potent antioxidant that increased in concentration to compensate for the lack of vitamin C synthesis in primate species ∼65 Ma. Here, we have expanded on our previous work with resurrected ancient uricase proteins to better resolve the reshaping of uricase enzymatic activity prior to ape evolution. Our results suggest that the pivotal death-knell to uricase activity occurred between 20 and 30 Ma despite small sequential modifications to its catalytic efficiency for the tens of millions of years since primates lost their ability to synthesize vitamin C, and thus the two appear uncorrelated. We also use this opportunity to demonstrate how molecular evolution can contribute to biomedicine by presenting ancient uricases to human immune cells that assay for innate reactivity against foreign antigens. A highly stable and highly catalytic ancient uricase is shown to elicit a lower immune response in more human haplotypes than other uricases currently in therapeutic development. 相似文献
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998.
E.tenella感染鸡CD4+、CD8+T细胞的动态变化研究 总被引:1,自引:0,他引:1
用免疫组化ABC法检测了柔嫩艾美耳球虫(E.tenella)感染雏鸡后各免疫器官和盲肠局部的T淋巴细胞亚群CD4 淋巴细胞和CD8 T淋巴细胞数的动态变化。结果表明:(1)雏鸡初次感染E.tenella后,免疫器官盲肠扁桃体、脾脏、胸腺和盲肠黏膜中的CD4 T淋巴细胞均于第2天开始增殖,第6天~8天达到峰值;二次感染后第2天有短暂的下降,第5天开始缓慢回升,第8天二次达到峰值,但第二个峰值比第一个峰值低,说明CD4 T淋巴细胞积极参与启动免疫应答和抵抗初次感染。(2)雏鸡初次感染E.tenella后,免疫器官法氏囊、盲肠扁桃体、脾脏、胸腺和盲肠黏膜中的CD8 T淋巴细胞都于第2天开始增殖,第8天达到峰值;二次感染后立即回升,第5天达到峰值,然后缓慢下降,且第二个峰值比第一个峰值高,表明CD8 T淋巴细胞是抵抗再感染的主力。 相似文献
999.
目的 研究上海地区人类免疫缺陷病毒1型(HIV-1)感染/艾滋病(AIDS)患者中HIV-1耐药株出现的情况及亚型分布。方法 对33例HIV-1感染/AIDS患者的血浆HIV-1分离株,进行抗HIV-1药物(核苷类反转录酶抑制剂、非核苷类反转录酶抑制剂和蛋白酶抑制剂)的基因型耐药检测和亚型分析。结果 33例的HIV-1均未检出对PI的耐药突变;10例高效抗反转录病毒疗法(HAART)治疗失败或抑制病毒复制不完全者中,检出的耐药突变为70%,过渡型耐药突变为20%;23例未经抗HIV-1治疗者中,耐药突变为4.3%,过渡型耐药突变为13%。所有过渡型耐药突变均为T215S。15例经血制品传播的HIV- 1均为B亚型;18例经吸毒和性传播的HIV-1中,B和CRF01-AE亚型分别为39%,和33%,此外,还有C、D、G、K和CRF02-AG亚型。结论 上海地区HIV-1感染/AIDS患者中,HAART治疗失败或复制抑制不完全者HIV-1的NRTI和NNRTI耐药突变率高;吸毒和性传播者的HIV-1中,除主要为B和CRF01-AE亚型外,尚有其他少见的亚型。 相似文献
1000.
Xiao Yu MengSheng Song PengZe Rong XianJun Chen Lin Shi ChengHao Wang QingJiang Pang 《Journal of cellular and molecular medicine》2022,26(1):60
Recent evidence indicates that the abnormal differentiation of bone marrow‐derived mesenchymal stem cells (BMSCs) plays a pivotal role in the pathogenesis of osteoporosis. LncRNA SNHG1 has been found to be associated with the differentiation ability of BMSCs. In this study, we aimed to elucidate the role of lncRNA SNHG1 and its associated pathway on the differentiation of BMSCs in osteoporosis. Mice that underwent bilateral ovariectomy (OVX) were used as models of osteoporosis. Induced osteogenic or adipogenic differentiation was performed in mouse BMSCs. Compared to sham animals, lncRNA SNHG1 expression was upregulated in OVX mice. Also, the in vitro expression of SNHG1 was increased in adipogenic BMSCs but decreased in osteogenic BMSCs. Moreover, overexpression of SNHG1 enhanced the adipogenic capacity of BMSCs but inhibited their osteogenic capacity as determined by oil red O, alizarin red, and alkaline phosphatase staining, while silencing of SNHG1 led to the opposite results. LncRNA SNHG1 interacting with the RNA‐binding polypyrimidine tract‐binding protein 1 (PTBP1) promoted osteoprotegerin (Opg) methylation and suppressed Opg expression via mediating DNA methyltransferase (DNMT) 1. Furthermore, Opg was showed to regulate BMSC differentiation. Knockdown of SNHG1 decreased the expressions of adipogenic related genes but increased that of osteogenic related genes. However, the knockdown of Opg partially reversed those effects. In summary, lncRNA SNHG1 upregulated the expression of DNMT1 via interacting with PTBP1, resulting in Opg hypermethylation and decreased Opg expression, which in turn enhanced BMSC adipogenic differentiation and contributed to osteoporosis. 相似文献