Solution structure of the N‐terminal domain of DC‐UbP/UBTD2 and its interaction with ubiquitin

DC‐UbP/UBTD2 is a ubiquitin (Ub) domain‐containing protein first identified from dendritic cells, and is implicated in ubiquitination pathway. The solution structure and backbone dynamics of the C‐terminal Ub‐like (UbL) domain were elucidated in our previous work. To further understand the biological function of DC‐UbP, we then solved the solution structure of the N‐terminal domain of DC‐UbP (DC‐UbP_N) and studied its Ub binding properties by NMR techniques. The results show that DC‐UbP_N holds a novel structural fold and acts as a Ub‐binding domain (UBD) but with low affinity. This implies that the DC‐UbP protein, composing of a combination of both UbL and UBD domains, might play an important role in regulating protein ubiquitination and delivery of ubiquitinated substrates in eukaryotic cells.     

Construction and Characterization of a CTLA-4-Targeted scFv–Melittin Fusion Protein as a Potential Immunosuppressive Agent for Organ Transplant

Immunotoxins with selective cytotoxicity are frequently used as therapeutic immunosuppressive agents in solid-organ transplantation because of their efficiency and high specificity. In this study, we present a new recombinant immunotoxin termed anti-CTLA-4-scFv–melittin prepared from Escherichia coli aimed at clearing activated T cells at the same time avoiding all-round decline in systematic immunity. This fusion protein is composed of anti-CTLA-4-scFv unit and melittin analog unit with properties of low immunogenicity and selective cytotoxicity to CTLA-4-positive T cells. In preliminary biological activity assays, our results confirmed the feasibility of activated T cell clearance strategy and there were significant differences in cell survival rates between CTLA-4-positive group and control group at all experimental concentrations of the immunotoxin. The selective cytotoxicity, low immunogenicity, and low production cost make it an attractive alternate to traditional immunosuppressants.     

U-Shape Suppressive Effect of Phenol Red on the Epileptiform Burst Activity via Activation of Estrogen Receptors in Primary Hippocampal Culture

Phenol red is widely used in cell culture as a pH indicator. Recently, it also has been reported to have estrogen-like bioactivity and be capable of promoting cell proliferation in different cell lines. However, the effect of phenol red on primary neuronal culture has never been investigated. By using patch clamp technique, we demonstrated that hippocampal pyramidal neurons cultured in neurobasal medium containing no phenol red had large depolarization-associated epileptiform bursting activities, which were rarely seen in neurons cultured in phenol red-containing medium. Further experiment data indicate that the suppressive effect of the phenol red on the abnormal epileptiform burst neuronal activities was U-shape dose related, with the most effective concentration at 28 µM. In addition, this concentration related inhibitory effect of phenol red on the epileptiform neuronal discharges was mimicked by 17-β-estradiol, an estrogen receptor agonist, and inhibited by ICI-182,780, an estrogen receptor antagonist. Our results suggest that estrogen receptor activation by phenol red in the culture medium prevents formation of abnormal, epileptiform burst activity. These studies highlight the importance of phenol red as estrogen receptor stimulator and cautions of careful use of phenol red in cell culture media.     

An efficient, practical synthesis of 2-methoxyestradiol

An efficient and practical scheme to synthesize 2-methoxyestradiol has been developed. The key step was the copper-mediated methoxylation using ethyl acetate as a co-catalyst to introduce a methoxyl group. These synthetic procedures of four steps from 17β-estradiol as starting material gave 2-methoxyestradiol with a 61% overall yield.     

感染环形泰勒焦虫(Theileria annulata)的牛外周血白细胞的形态观察

用光镜及扫描电镜观察了体外高代培养的含牛焦虫颗粒的牛外周血白细胞的形态及在细胞周期中细胞表面的特征性变化。这种经多年传代的含虫的牛外周血白细胞恢复了分裂和繁殖的能力,目前已成为较稳定的细胞系。细胞表面具多种伪足突起,如叶状、丝状及绒毛状。细胞周期中备期细胞表面的主要特征是:S期:细胞平扁,边缘具薄的时状伪足及丝状伪足;G_2期:细胞中部隆起,表面具少量绒毛状伪足;G_1期:绒毛状结构少或无,而出现丝状及小的叶状伪足,细胞仍保持球形;M期:细胞球形,表面密被以绒毛。作者根据扫描电镜的观察认为光镜下所观察的两类细胞,实际上是反映了一种细胞处于不同发育阶段时的特征。     

A review of the distribution of all species of deer (Tragulidae, Moschidae and Cervidae) in China

Twenty-one species of deer occur in China: one species of Tragulidae, three species of Moschidae and 17 species of Cervidae. The foundation of this review is the research conducted in the early 1940s by Allen, combined with the research and investigation by the authors and other Chinese specialists since that time. This paper focuses on the tentative distribution of these species of deer for future research efforts.     

康定虫草主要寄主斜脉蝠蛾的研究

冬虫夏草是一味名贵的中药材.四川康定虫草的主要寄主斜脉蝠蛾翅面色斑多变异,可区分成“黑白斑”和“黄毛斑”两大色斑型.经交配试验和成虫形态特征(触角、口器、翅脉、前足、雌雄外生殖器和鳞片的超微结构等)的观察,证明为同一种,经鉴定是斜脉蝠蛾(Hepialus oblifurcus Chu et Wang)^**.     

黄海车牛山岛白腰雨燕的繁殖习性及种群动态

本文为作者于1980—1981年对黄海车牛山岛白腰雨燕Apuspacificus pacificus (Latham)的初步研究。内容包括对繁殖习性的观察;对繁殖周期、卵孵化率、雏鸟成活串以及出生率等的统计。并对海岛生态环境下白腰雨燕种群数量的变动及其影响因素,作初步探讨。     

蛙卵黄粒晶形区向非晶区过渡的电镜观察及伪彩色图象处理

用水溶性氨基树脂作为电镜标本包埋介质包埋早期卵裂时的黑龙江林蛙卵;用透射电镜观察了卵黄粒晶形体向非晶区转变的过程;一部分电镜照片用伪彩色图象处理技术转换成彩色照片以提高其清晰度。晶形体向非晶结构转化主要有两种形式:1.沿晶形体表面成排地脱落晶分子并在晶形体表面形成台阶样结构;2.晶分子参差不齐地成群脱离晶形体并在晶形区与非晶区之间形成一个似晶非晶的过渡区。脱离晶形体后的晶分子参加到非晶区,使深色亚区扩大并在其中酝酿成“微滴”样结构。若干“微滴”汇合并转变成微泡。伪彩色图象处理能较清楚地显示出卵脂蛋白半分子(一个亚单位)独立脱离晶形体的现象。讨论了引起晶分子脱离晶形体的可能??原因。