哺乳动物精原干细胞体外分离培养研究进展

精原干细胞(spermatogonial stem cells,SSCs)作为成体干细胞的一种,具有高度自我更新和分化潜能。近几年研究发现,SSCs的体外培养是表观遗传基础研究、精子发生机制深入探索以及治疗雄性不育的基础条件。本文根据国内外SSCs相关研究,对哺乳动物SSCs的生物学特性、体外分离培养和鉴定等作一综述,以期为哺乳动物SSCs和其他干细胞的长期体外培养以及建系提供一定的借鉴。     

精原干细胞的生物学特性

精原干细胞(spermatogonialstemcells,SSCs)是雄性生殖系干细胞,位于睾丸曲细精管基膜上,既具有自我更新潜能,又具有定向分化潜能,是自然状态下出生后动物体内在整个生命期间进行自我更新并能将基因传递至子代的唯一成体干细胞。自SSCs移植技术建立以来,有关其分离、鉴定、培养、冻存、转基因操作及移植等方面均已取得长足进步,使人们对其生物学特性有了更深入的了解。根据最近的相关进展,系统评述了SSCs的相关生物学特性,以期为该领域及其他干细胞研究提供借鉴。     

非人灵长类动物精原干细胞研究进展

精原干细胞（spermatogonial stem cells,SSCs）是维持精子发生的一类干细胞,由于与人亲缘关系的相近性,使得开展非人灵长类动物SSCs研究具有重要的理论意义和比较医学价值。本文综述了非人灵长类动物SSCs的生物学特性、鉴定方法、冷冻保存、移植及生精细胞缺失模型建立等方面的研究进展。     

哺乳动物精原干细胞的分子标记及调控

精原干细胞(spermatogonial stem cells,SSCs)是一群生活在睾丸特殊微环境中并能自我更新和具有多向分化潜能的细胞,是精子发生的基础。近年来,通过对SSCs表面的α6-和β1-整合素、CD9、GFRA1等主要标记分子,以及对GDNF、Plzf、泛素、LIF等决定SSCs自我更新和分化的多种细胞因子和基因的研究发现,目前在SSCs的分离、鉴定和生物学特性方面已获得新的成果。本文简述了目前哺乳动物SSCs主要的标记分子及自我更新与分化的调控机理,以期为该领域及其他干细胞研究提供一定的借鉴。     

精原干细胞分离、鉴定、培养及其应用进展

雄性哺乳动物睾丸内持续的精子发生是维持其生殖能力的必备条件。精原干细胞(SSCs)是精子发生的基础,是永久分化成精子的克隆源,它既可以自我更新维持体内干细胞的数量,又可以增殖分化形成各阶段的生精细胞直至成熟精子。现对SSCs分离、鉴定与培养等技术及其应用的进展进行综述,发现两步酶消化、差异贴壁、磁珠分选等方法是体外分离与纯化SSCs的常用方法。特异性标志物的研究一直在推进SSCs的纯化与鉴定,并仍将是SSCs技术的研究重点之一。培养基、血清、生长因子和饲养层在SSCs体外培养中至关重要,但长期培养中血清可引起SSCs分化的问题有待解决。在基础与临床方面的应用中,SSCs体外培养系统为研究精子发生过程、遗传学、雄性辅助生殖和细胞再生治疗等开辟了新的道路。     

精原干细胞技术研究进展

精原干细胞(spermatogonial stem cells,SSCs)是位于睾丸曲细精管基膜上能自我更新和连续分化产生精子的最原始精原细胞,是雄性体内唯一能将遗传信息自然传至子代并可终生复制的双倍体细胞,对复杂的精子发生过程有着至关重要的作用。作为一个未分化细胞群体,SSCs在精子生成和物种进化所必需的基因传递中发挥作用。基于课题组多年的研究,该文较系统地评述了SSCs的生物学特性、分离富集、体外培养影响因素和移植技术等方面的进展,以期对雄性辅助生殖、细胞再生治疗、畜牧业生产等研究应用提供借鉴。     

免疫磁珠纯化小鼠精原干细胞的研究

精原干细胞（spermatogonial stem cells,SSCs）富集纯化是利用SSCs进行基因修饰新方法等研究的前提基础。采用免疫磁珠分选法,使用干细胞抗体CD90.2进行小鼠SSCs的纯化富集,并采用流式细胞分析法和定量PCR验证了磁珠分选效率。流式细胞分析结果：免疫磁珠分选后SSCs纯度为50.11%。荧光定量PCR检测结果：磁珠分选后支持细胞特异表达基因 GATA4 显著下调（6倍）、SSCs表达基因 GFRα-1 上调（6.5倍）、生殖干细胞特异表达基因 OCT4 极显著上调（5.9倍）,3个基因相对表达量的变化说明,免疫磁珠分选效率为6倍。流式细胞分析法所产生的偏差可能是受到了未解离磁珠及SSCs本身转基因荧光的影响。     

水牛精原干细胞研究进展

精原干细胞(SSCs)是一类能够不断地进行自我更新和分化,并能保证遗传物质在亲子代之间有效传递的成体干细胞。伴随着各种移植技术、细胞体外培养及冻存等技术的发展,精原干细胞的应用成为可能,其在生产转基因动物及保护珍稀物种等方面有着广阔的应用前景。本文对水牛SSCs的生成、分离、纯化、培养、鉴定以及冻存的研究进行了系统的阐述。     

小鼠精原干细胞在三种培养基中的生长行为

目的：建立小鼠精原干细胞（SSCs）的体外长期培养体系。方法：用分别添加了等量的胶质细胞源神经营养因子（GDNF）、可溶性GFRα1和hFGF的DMEM／F12、KSR和StemPro-34 SFM三种无血清培养基和MEF饲养层分别培养经差异贴壁分选富集的小鼠SSCs,通过形态观察、标志基因的RT-PCR和免疫细胞化学分析检测其SSCs本原。结果：DMEM／F12与KSR可支持小鼠SSCs在体外存活6-7d,而StemPro-34 SFM能能维持SSCs体外增值一个月。结论：StemPro-34 SFM支持小鼠SSCs的体外增殖。     

哺乳动物精原干细胞的增殖分化及其移植技术的应用

精原干细胞(spermatogonial stem cells,SSCs)是指位于睾丸生精小管基膜上既能自我更新以维持自身群体数量恒定,又能定向分化形成精母细胞,最终形成精子的一类成体干细胞.鉴于其独具的生物学特性,SSCs的研究在干细胞生物学、医学、畜牧业等领域均具有重要意义.通过其建立转基因动物模型,对研究精子的发生机制、重建不育个体的生精功能等都有着重要意义.综述了哺乳动物SSCs的形态特性,增殖分化特性及其调控因素,简述了SSCs移植技术的应用.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细