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971.
Glycolytic enzymes localize to ribonucleoprotein granules in Drosophila germ cells,bind Tudor and protect from transposable elements 下载免费PDF全文
T Michael Creed Shikui Tu Sudan N Loganathan Christina A Jackson Patrick McCluskey Yanyan Lin Scott E Collier Zhiping Weng Paul Lasko Melanie D Ohi Alexey L Arkov 《EMBO reports》2015,16(3):379-386
Germ cells give rise to all cell lineages in the next‐generation and are responsible for the continuity of life. In a variety of organisms, germ cells and stem cells contain large ribonucleoprotein granules. Although these particles were discovered more than 100 years ago, their assembly and functions are not well understood. Here we report that glycolytic enzymes are components of these granules in Drosophila germ cells and both their mRNAs and the enzymes themselves are enriched in germ cells. We show that these enzymes are specifically required for germ cell development and that they protect their genomes from transposable elements, providing the first link between metabolism and transposon silencing. We further demonstrate that in the granules, glycolytic enzymes associate with the evolutionarily conserved Tudor protein. Our biochemical and single‐particle EM structural analyses of purified Tudor show a flexible molecule and suggest a mechanism for the recruitment of glycolytic enzymes to the granules. Our data indicate that germ cells, similarly to stem cells and tumor cells, might prefer to produce energy through the glycolytic pathway, thus linking a particular metabolism to pluripotency. 相似文献
972.
BackgroundThree-dimensional computed tomographic imaging has become popular in clinical evaluation, treatment planning, surgical simulation, and outcome assessment for maxillofacial intervention. The purposes of this study were to investigate whether there is any correlation among landmark-based horizontal reference planes and to validate the reproducibility and reliability of landmark identification.ResultsA total of 30 patients with facial deformity and malocclusion—10 patients with facial symmetry, 10 patients with facial asymmetry, and 10 patients with cleft lip and palate—were recruited. Comparing the differences among the 5 reference planes showed no statistically significant difference among all patient groups. Regarding intraobserver reproducibility, the mean differences in the 3 coordinates varied from 0 to 0.35 mm, with correlation coefficients between 0.96 and 1.0, showing high correlation between repeated tests. Regarding interobserver reliability, the mean differences among the 3 coordinates varied from 0 to 0.47 mm, with correlation coefficients between 0.88 and 1.0, exhibiting high correlation between the different examiners.ConclusionsThe 5 horizontal reference planes were reliable and comparable for 3D craniomaxillofacial analysis. These reference planes were useful in standardizing the orientation of 3D skull models. 相似文献
973.
Hydrogen bond interactions of G proteins with the guanine ring moiety of guanine nucleotides. 下载免费PDF全文
G. Weng C. X. Chen V. Balogh-Nair R. Callender D. Manor 《Protein science : a publication of the Protein Society》1994,3(1):22-29
We have utilized Raman difference spectroscopy to investigate hydrogen bonding interactions of the guanine moiety in guanine nucleotides with the binding site of two G proteins, EF-Tu (elongation factor Tu from Escherichia coli) and the c-Harvey ras protein, p21 (the gene product of the human c-H-ras proto-oncogene). Raman spectra of proteins complexed with GDP (guanosine 5' diphosphate), IDP (inosine 5' diphosphate), 6-thio-GDP, and 6-18O-GDP were measured, and the various difference spectra were determined. These were compared to the difference spectra obtained in solution, revealing vibrational features of the nucleotide that are altered upon binding. Specifically, we observed significant frequency shifts in the vibrational modes associated with the 6-keto and 2-amino positions of the guanine group of GDP and IDP that result from hydrogen bonding interactions between these groups and the two proteins. These shifts are interpreted as being proportional to the local energy of interaction (delta H) between the two groups and protein residues at the nucleotide binding site. Consistent with the tight binding between the nucleotides and the two proteins, the shifts indicate that the enthalpic interactions are stronger between these two polar groups and protein than with water. In general, the spectral shifts provide a rationale for the stronger binding of GDP and IDP with p21 compared to EF-Tu. Despite the structural similarity of the binding sites of EF-Tu and p21, the strengths of the observed hydrogen bonds at the 6-keto and 2-amino positions vary substantially, by up to a factor of 2.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
974.
975.
中国人群遗传结构分析 总被引:1,自引:0,他引:1
本文根据红细胞血型基因频率,用Harpending和Jenkins(1973)方法计算了中国22个人群间的遗传距离,同时在国内首次运用主坐标分析及其排序方法展示了中华民族的遗传结构,反映出中国东西人群与南北人群间的基因流。 相似文献
976.
目的探讨骨髓间充质干细胞(MSCs)对肾移植受者T淋巴细胞分化和miRNA-155表达的影响。
方法选取2013年1月至2017年12月于福州总医院接受MSCs诱导+同种异体肾移植术的受者20例(MSCs组),对照组为同期配对的异体肾移植受者20例。两组患者术后免疫抑制方案均为霉酚酸酯+他克莫司+强的松。两组患者分别于移植术前、术后第15天抽取静脉血,流式细胞仪检测外周血CD4+ CD25+ FoxP3+ Treg细胞/?CD4+细胞亚群比值;ELISA检测白细胞介素2(IL-2)、肿瘤坏死因子α(TNF-α)和白细胞介素10(IL-10)浓度;免疫磁珠分选外周血T淋巴细胞后,Rea1-time PCR法检测外周血T淋巴细胞中miRNA-?155的表达。两组间均数比较采用独立t检验,治疗前后均数比较采用配对t检验。
结果移植前两组肾移植受者外周血CD4+ CD25+ FoxP3+ Treg细胞/?CD4+细胞比值、IL-2、IL-?10、TNF-α、T淋巴细胞miRNA-155表达水平差异均无统计学意义(P均> 0.05);术后第15天,与对照组相比,MSCs组外周血CD4+ CD25+ FoxP3+ Treg细胞/?CD4+细胞亚群比值(30.44﹪?± 4.23﹪? vs 26.06﹪?±4.77﹪,t = 2.365,P = 0.042)、IL-10水平(20.35?ng/?L?±?5.10?ng/?L? vs 16.63?ng/?L±6.26?ng/?L,t = 2.062,P?=?0.046)上升,而IL-2(27.47ng/?L±4.30 ng/?L vs 31.40?ng/?L±5.33 ng/L,t = 2.252,P = 0.015)、TNF-α(41.52?ng/?L±8.32?ng/L vs 46.67?ng/?L±6.71?ng/L,t = 2.157,P = 0.037)和T淋巴细胞miRNA-155表达水平(1.61±0.31 vs 1.89±0.15,t = 3.688,P?= 0.001)则降低。
结论MSCs能够升高肾移植受者外周血CD4+ CD25+ FoxP3+ Treg细胞/?CD4+细胞比值和IL-10水平,降低IL-2、TNF-α和T淋巴细胞miRNA-155表达水平,与MSCs的免疫耐受诱导有关。 相似文献
977.
978.
Yu-Xiang Zhang Yan Liu Jing Dong You-Xin Wang Jing Wang Guo-Qing Zhuang Shu-Jing Han Qing-Qing Guo Yan-Xia Luo Jie Zhang Xiao-Xia Peng Ling Zhang Yu-Xiang Yan Xing-hua Yang Hong Wang Xu Han Guang-Xu Liu You-Hou Kang You-Qin Liu Sheng-Feng Weng Hong Zhang Xiao-Qiang Zhang Ke-Bao Jia Li Wang Lei Zhao Zhong-Xin Xiao Shu-Hua Zhang Hui-Hui Wu Qing-Xuan Lai Na Qi Wei Wang Herbert Gaisano Fen Liu Yan He 《PloS one》2013,8(2)
Since the KCNB1 encoding Kv2.1 channel accounts for the majority of Kv currents modulating insulin secretion by pancreatic islet beta-cells, we postulated that KCNB1 is a plausible candidate gene for genetic variation contributing to the variable compensatory secretory function of beta-cells in type-2 diabetes (T2D). We conducted two studies, a case-control study and a cross-section study, to investigate the association of common single-nucleotide polymorphisms (SNPs) in KCNB1 with T2D and its linking traits. In the case-control study, we first examined the association of 20 tag SNPs of KCNB1 with T2D in a population with 226 T2D patients and non-diabetic subjects (screening study). We then identified the association in an enlarged population of 412 T2D patients and non-diabetic subjects (replication study). In the cross-sectional study, we investigated the linkage between the candidate SNP rs1051295 and T2D by comparing beta-cell function and insulin sensitivity among rs1051295 genotypes in a general population of 1051 subjects at fasting and after glucose loading (oral glucose tolerance tests, OGTT) in 84 fasting glucose impaired subjects, and several T2D-related traits. We found that among the 19 available tag SNPs, only the KCNB1 rs1051295 was associated with T2D (P = 0.027), with the rs1051295 TT genotype associated with an increased risk of T2D compared with genotypes CC (P = 0.009). At fasting, rs1051295 genotype TT was associated with a 9.8% reduction in insulin sensitivity compared to CC (P = 0.008); along with increased plasma triglycerides (TG) levels (TT/CC: P = 0.046) and increased waist/hip (W/H) ratio (TT/CC: P = 0.013; TT/TC: P = 0.002). OGTT confirmed that genotype TT exhibited reduced insulin sensitivity by 16.3% (P = 0.030) compared with genotype TC+CC in a fasting glucose impaired population. The KCNB1 rs1051295 genotype TT in the Chinese Han population is associated with decreased insulin sensitivity and increased plasma TG and W/H ratio, which together contribute to an increased risk for T2D. 相似文献
979.
华南虎血液及生物化学某些指标的测定 总被引:11,自引:0,他引:11
用血液及生物化学的常规测定方法对61例华南虎的血液常规,30余例血液生化指标进行了分析测定,经生物学统计获得了华南虎的血液和生物化学的参考值。 相似文献
980.
Weng XH Beyenbach KW Quaroni A 《American journal of physiology. Gastrointestinal and liver physiology》2005,288(4):G705-G717
The development of a culture of the normal mammalian jejunum motivated this work. Isolated crypt cells of the dog jejunum were induced to form primary cultures on Snapwell filters. Up to seven subcultures were studied under the electron microscope and in Ussing chambers. Epithelial markers were identified by RT-PCR, Western blot, and immunofluorescent staining. Confluent monolayers exhibit a dense apical brush border, basolateral membrane infoldings, desmosomes, and tight junctions expressing zonula occludens-1, occludin-1, and claudin-3 and -4. In OptiMEM medium fortified with epidermal growth factor, hydrocortisone, and insulin, monolayer transepithelial voltage was -6.8 mV (apical side), transepithelial resistance was 1,050 Omega.cm(2), and short-circuit current (I(sc)) was 8.1 microA/cm(2). Transcellular and paracellular resistances were estimated as 14.8 and 1.1 kOmega.cm(2), respectively. Serosal ouabain reduced voltage and current toward zero, as did apical amiloride. The presence of mRNA of alpha-epithelial Na(+) channel (ENaC) was confirmed. Na-d-glucose cotransport was identified with an antibody to Na(+)-glucose cotransporter (SGLT) 1. The unidirectional mucosa-to-serosa Na(+) flux (19 nmol.min(-1).cm(-2)) was two times as large as the reverse flux, and net transepithelial Na(+) flux was nearly double the amiloride-sensitive I(sc). In plain Ringer solution, the amiloride-sensitive I(sc) went toward zero. Under these conditions plus mucosal amiloride, serosal dibutyryl-cAMP elicited a Cl(-)-dependent I(sc) consistent with the stimulation of transepithelial Cl(-) secretion. In conclusion, primary cultures and subcultures of the normal mammalian jejunum form polarized epithelial monolayers with 1) the properties of a leaky epithelium, 2) claudins specific to the jejunal tight junction, 3) transepithelial Na(+) absorption mediated in part by SGLT1 and ENaC, and 4) electrogenic Cl(-) secretion activated by cAMP. 相似文献