The yeast VPS genes affect telomere length regulation

Eukaryotic cells invest a large proportion of their genome in maintaining telomere length homeostasis. Among the 173 non-essential yeast genes found to affect telomere length, a large proportion is involved in vacuolar traffic. When mutated, these vacuolar protein-sorting (VPS) genes lead to telomeres shorter than those observed in the wild type. Using genetic analysis, we characterized the pathway by which VPS15, VPS34, VPS22, VPS23 and VPS28 affect the telomeres. Our results indicate that these VPS genes affect telomere length through a single pathway and that this effect requires the activity of telomerase and the Ku heterodimer, but not the activity of Tel1p or Rif2p. We present models to explain the link between vacuolar traffic and telomere length homeostasis.     

Light and electron microscopic studies on rat arterial lesions induced by experimental arterial contraction

Summary Experimental contraction was produced in the rat mesenteric arteries and the arterial segments were studied morphologically. When the rat mesenteric artery was exposed in physiological saline solution at 37° C and 2–3 mg of methoxamine hydrochloride (10 mg/ml) was dripped onto it, intense contraction was observed for about 30 min but elevation in blood pressure was slight. During the contraction, numerous vacuoles were seen in the medial smooth muscle cells of the arterial segments, and these vacuoles were shown electron microscopically to have double unit membranes, indicating that they were formed by herniation of a part of the adjacent smooth muscle cell body. In the arteries 1–6 h after the end of the contraction, cellular, nuclear and vacuolar membranes and myofilaments of the medial muscle cells were partially lost. 12–24 h after the contraction the arteries exhibited necrosis and desquamation of endothelial cells and platelet adhesion. In the media, smooth muscle cells were completely deprived of cell membranes, myofilaments, nuclei, intracytoplasmic organelles other than mitochondria, and vacuolar membranes. The cytoplasm was filled with fine granular and granulo-vesicular material, and fibrin insudation was observed in these severely damaged cells. Arterial contraction may be an important factor in the induction of arterial lesions.     

Study of the substructure of the Morgagni and Brunescens cataract with the TAO non-coating technique

Lens tissue from a Morgagni cataract was examined by SEM and TEM. For SEM, after prefixation with glutaraldehyde and postfixation with the tannic acid/arginine/OsO₄ non-coating (TAO) technique, and for TEM, after prefixation with glutaraldehyde, postfixation with OsO₄/K₄Fe(CN)₆ and poststaining with uranyl acetate/lead citrate. The TAO technique seems to be a particularly suitable postfixation method for the SEM investigation of cararact tissue because of the presence of the protein structures present. The cortical region showed areas of radially, instead of concentrically, arranged lens fibres, degenerated lens fibres with holes (vacuoles), broken ball and socket connections between the lens fibres, and oval or spherical structures varying in size from 0.5–20 m, the largest resembling a golfball, arising from the cytoplasm of degenerating lens fibres. The smallest, 0.2–0.5 m, appear to have been expelled from the furrowed lens epithelium.     

胃炎患者血清幽门螺杆菌分类抗体免疫印迹检测的临床意义

目的:研究胃炎患者血清幽门螺杆菌分类抗体免疫印迹检测的临床意义。方法:用14C呼气试验检测幽门螺杆菌感染;用免疫印迹法检测幽门螺杆菌分类抗体。结果:152例临床各型胃炎患者中,140人14C-呼气试验阳性(92.11%)。14C-呼气试验阳性组Hp分类抗体中CagA、VacA双阳性或单项阳性者127人(90.71%);阳性预测值90.7%,阴性预测值9.3%。结论:14C-呼气试验与幽门螺杆菌分类抗体两种方法组合检测,对临床幽门螺杆菌的诊断与治疗有重要作用;免疫印迹法检测幽门螺杆菌分类抗体,有简便、敏感、特异、快速的优点。     

雌性大鼠动情周期中黄体生成素细胞形态变化的图像分析

应用特异性的ａ－ｒＬＨβ抗血清，以ＡＢＣ技术显示垂体黄体生成素（ＬＨ）细胞，通过计算机图像处理系统对ＬＨ细胞的面积，、细胞内液泡面积和细胞形状等参数进行定量和统计分析，获得了大鼠正常动情周期各时期典型的ＬＨ细胞学图像。结果表明，ＬＨ的早期贮存和基础主要同细胞内颗粒变化有是ＬＨ的大量贮存和大量释放同细胞内液泡的变化以及由此产生的细胞大小、细胞形状和细胞结构等形态变化密切相关。提出ＬＨ细胞内液泡变化是     

A quantitative assay to measure homotypic vacuole fusion in vitro

Homotypic (self) vacuole fusion is the last discernible step in vacuole inheritance ofSaccharomyces cerevisiae and was recently successfully reconstituted in vitro using purified vacuoles, cytosol, ATP, moderate salt concentrations, and a physiological temperature. The following protocol describes a rapid, reliable, and easy technique to quantitate homotypic vacuole fusion in vitro. Frequency of fusion is determined by quantifying alkaline phosphatase activity after fusion has taken place. This method has been successfully used to analyze pharmacological reagents which interfere with certain subreactions and to identify distinct proteins which play key roles in the fusion events.     

Podospora anserina target of rapamycin

We have isolated the Podospora anserina TOR gene. The PaTOR protein displayed strong identities with TOR proteins from other eukaryotes especially in the FRB domain and the kinase domain. Genome analysis suggests that a single TOR gene exists in Podospora. The serine residue known to be one site of missense mutations conferring rapamycin resistance in other organisms is conserved in the PaTOR protein (S1895). A PaTOR-S1895R mutated allele has been constructed and introduced in the wild-type strain, as expected strains expressing the PaTOR-S1895R gene become resistant to rapamycin. The dominance of the PaTOR-S1895R allele indicates that apparently the mutation does not impair the kinase activity. We confirm that all cytological modifications associated with rapamycin treatment in Podospora are indeed mediated by PaTOR. We conclude that the PaTOR gene is likely to be essential and that rapamycin treatment might be useful to further investigate rapamycin-sensitive TOR functions in Podospora and especially newly identified rapamycin-sensitive functions such as the autophagy-independent control of vacuole remodeling and septation.     

大白鼠垂体促性腺激素细胞分泌周期中颗粒和液泡结构的周期性变化

本文用光学和电子显微镜观察大白鼠垂体促性腺激素细胞分泌周期中细胞质内颗粒和液泡结构的变化。根据其变化特征,将垂体促性腺激素细胞区分为颗粒A型和B型、液泡A型和B型四类。随着促性腺激素的贮存和释放过程,这四种类型的细胞发生周期性变化。在激素贮存的早期阶段,细胞形态的变化主要与颗粒的变化有关,而在激素大量贮存和大量释放时,其相应的形态学变化则是细胞质内的液泡化和空泡化。因此作者认为:促性腺激素的贮存和释放与细胞质内颗粒及液泡结构的变化有着极密切的关系。