A neutralizing antibody selected from plasma cells that binds to group 1 and group 2 influenza A hemagglutinins

The isolation of broadly neutralizing antibodies against influenza A viruses has been a long-sought goal for therapeutic approaches and vaccine design. Using a single-cell culture method for screening large numbers of human plasma cells, we isolated a neutralizing monoclonal antibody that recognized the hemagglutinin (HA) glycoprotein of all 16 subtypes and neutralized both group 1 and group 2 influenza A viruses. Passive transfer of this antibody conferred protection to mice and ferrets. Complexes with HAs from the group 1 H1 and the group 2 H3 subtypes analyzed by x-ray crystallography showed that the antibody bound to a conserved epitope in the F subdomain. This antibody may be used for passive protection and to inform vaccine design because of its broad specificity and neutralization potency.     

持续、低剂量金霉素对肉仔鸡免疫机能的抑制作用研究

270只Abore Acre商品代肉用公鸡随机分成3组，金霉素在饲料中添加水平分别为0、50只和150mg/kg，研究饲用金霉素对肉仔鸡法氏囊、脾脏和胸腺等免疫器官发育、以及免疫反应的影响。结果表明50mg/kg的金霉素对肉仔鸡脾脏和21日龄的胸腺无明显抑制作用，对T、B淋巴细胞转化率也无明显抑制作用（P＜0.05），而且显著促进法氏囊的萎缩（P＜0.05）。金霉素对T淋巴细胞转化率有明显的直接抑制作用；50mg/kg和150mg/kg的金素对BAS特异性抗体的产生均有显著的抑制作用（P＜0.01）。研究结果表明，持续、低剂量和金霉素对肉 鸡免疫器官发育和免疫应答具有显著的抑制作用，抑制作用随剂量增加而加强，150mg/kg的金霉素对肉仔鸡具有显著促生长作用。     

持续、低剂量金霉素对肉仔鸡免疫机能的抑制作用研究

 ２７０只 Ａｂｏｒｅ Ａｃｒｅ商品代肉用公鸡随机分成 ３组，金霉素在饲料中添加水平分别为 ０．５０和 １５０ｍｇ／ｋｇ，研究饲用金霉素对肉仔鸡法氏囊、脾脏和胸腺等免疫器官发育、以及免疫反应的影响。结果表明，５０ｍｇ／ｋｇ的金霉素对肉仔鸡脾脏和 ２１日龄的胸腺无明显抑制作用，对 Ｔ、Ｂ淋巴细胞转化率也无明显抑制作用；１５０ｍｇ／ｋｇ的金霉素对肉仔鸡的胸腺和脾脏发育具有显著的抑制作用（Ｐ＜０．０５），而且显著促进法氏囊的萎缩（Ｐ＜０．０５）。金霉素对Ｔ淋巴细胞转化率有明显的直接抑制作用；５０ｍｇ／ｋｇ和１５０ｍｇ／ｋｇ的金霉素对ＢＳＡ特异性抗体的产生均有显著的抑制作用（Ｐ＜０．０１）。研究结果表明，持续、低剂量的金霉素对肉仔鸡免疫器官发育和免疫应答具有显著的抑制作用，抑制作用随剂量增加而加强。１５０ｍｇ／ｋｇ的金霉素对肉仔鸡具有显著促生长作用。     

Immunosuppressant Effect of Long Term and Subtherapeutic Chlortetracycline in Broiler

Experiments were conducted with 270 Abore Acre male broilers to study the influence of dietary chlortetracycline (CTC) on the bursal, thymus and spleen weight index and T, B cell proliferation and antibody responses of broilers. Results show that 50mg/kg CTC had no significant inhibitory effect on thymus and spleen weight index, and T, B cell proliferation of broilers at 21 days old. 150mg/kg CTC had significant inhibitory effect on bursal, thymus and spleen, and T, B cell proliferation (P＜0.05). Dietary CTC had a direct inhibitory effect on lymphocyte proliferation in vitro. 50mg/kg and 150mg/kg CTC had a significant inhibitory effect on the antibody responses to BSA (P＜0.01). Results demonstrated that subtherapeutic and long term CTC had significant inhibitory effects on immune organs and antibody response. The immunosuppressant effect became higher when the level of CTC increased. 150mg/kg CTC increased the growth rate of broilers significantly.     

Group A streptococci: localization in rabbits and guinea pigs following tissue injury

Rabbits injected intravenously with extracellular products ("toxins") of group A streptococci develop myocardial, muscular, and hepatic lesions. When such animals are then challenged with fluorochrome-labeled group A streptococci or with titanium oxide particles the labeled bacteria or particles localize within phagocytic cells in the tissue lesions caused by the toxins. Similarly, labeled streptococci or titanium oxide particles will also localize within phagocytic cells in skin lesions of guinea pigs that develop delayed hypersensitivity to tuberculin or to bovine gamma globulin. It is proposed that a combined mechanism of injury and localization of bacteria in damaged tissues may be responsible for poststreptococcal sequelae or other chronic inflammatory diseases.     

A群链球菌脂磷壁酸的提取纯化及其抑瘤活性

为了研究A群链球菌制剂中的活性成分脂磷壁酸(LTA)的提纯方法和抗肿瘤活性,以A群链球菌为出发菌株,采用冷酚法提取A群链球菌制剂中的活性成分脂磷壁酸,经Sepharose CL-4B纯化,用红外图谱比较与脂磷壁酸标品(从金黄色葡萄球菌中提取得到)结构的类同,用气相色谱分析脂磷壁酸中脂肪酸和单糖结构组成,并研究脂磷壁酸的抑瘤活性.结果表明:纯化后的脂磷壁酸所含的蛋白质和核酸污染很低,脂磷壁酸的成分中有甘油磷酸基本骨架、脂肪酸和单糖结构;活性试验证明LTA对子宫癌细胞(Hela细胞)、腹水型EAC瘤和S_180肿瘤具有一定的抑制作用.     

Myosin: a link between streptococci and heart

Murine monoclonal antibodies to Streptococcus pyogenes reacted with skeletal muscle myosin. High molecular weight proteins in extracts of human heart tissue that reacted with an antibody to S. pyogenes also reacted with a monoclonal antibody to ventricular myosin. Adsorption of the antibody to streptococci with S. pyogenes simultaneously removed reactivity of the antibody for either S. pyogenes or myosin. These results indicate that myosin shares immunodeterminants with a component of S. pyogenes.     

Absence of glycerol teichoic acids in certain oral streptococci

Glycerol teichoic acids were not detected immunochemically or chemically in phenol-water, hot saline (Rantz and Randall), or supernatant fluids of disrupted cells of Streptococcus mitis. Thus teichoic acids do not appear to be found in most Gram-positive bacteria, as has been suggested.     

Autophagy defends cells against invading group A Streptococcus

We found that the autophagic machinery could effectively eliminate pathogenic group A Streptococcus (GAS) within nonphagocytic cells. After escaping from endosomes into the cytoplasm, GAS became enveloped by autophagosome-like compartments and were killed upon fusion of these compartments with lysosomes. In autophagy-deficient Atg5-/- cells, GAS survived, multiplied, and were released from the cells. Thus, the autophagic machinery can act as an innate defense system against invading pathogens.     

A highly conserved neutralizing epitope on group 2 influenza A viruses

Current flu vaccines provide only limited coverage against seasonal strains of influenza viruses. The identification of V(H)1-69 antibodies that broadly neutralize almost all influenza A group 1 viruses constituted a breakthrough in the influenza field. Here, we report the isolation and characterization of a human monoclonal antibody CR8020 with broad neutralizing activity against most group 2 viruses, including H3N2 and H7N7, which cause severe human infection. The crystal structure of Fab CR8020 with the 1968 pandemic H3 hemagglutinin (HA) reveals a highly conserved epitope in the HA stalk distinct from the epitope recognized by the V(H)1-69 group 1 antibodies. Thus, a cocktail of two antibodies may be sufficient to neutralize most influenza A subtypes and, hence, enable development of a universal flu vaccine and broad-spectrum antibody therapies.     

二棱大麦LEA cDNA的克隆与测序

从二棱大麦 ( H ordeum distichon Linn.)幼苗中提取总 RNA,通过 RT- PCR获得目的片段 HDCS1 ,并采用 T-载体进行克隆。测序结果表明 ,HDCS1全长 664bp,含有 1个完整的阅读框架。其编码蛋白质全长 2 0 2个氨基酸 ,含有 8个由 1 1个氨基酸残基组成的基元序列 ,属第 3组 LEA蛋白。HDCS1与大麦 ( H ordeum vulgare L.) L EA蛋白、HVA1具有高度同源性 ,其差异在于 HDCS1比 HVA1缺少一个完整的由 1 1个氨基酸残基组成的基元序列     

2003～2006年《广西农业科学》载文作者群分析

为总结办刊经验,提高刊物质量,对2003~2006年《广西农业科学》载文第一作者的基本情况、论文合作情况、作者所属系统及地区分布、作者所在单位等信息资料进行统计分析。结果表明,《广西农业科学》已拥有一批高素质、相对稳定的以中青年科技人员为主的活跃的作者群,并具有一定的知名度和影响力。今后,应努力提高《广西农业科学》的学术性和知名度,提高办刊质量,以吸引更多的高素质作者投稿,增加作者源。     

Chitinozoans from the late precambrian chuar group of the grand canyon, Arizona

Carbonaceous shales of the late Precambrian Chuar Group of the Grand Canyon, Arizona, contain abundant and well-preserved chitinozoans. The occurrence of these distinctive, tear- and flask-shaped microfossils, the oldest chitinozoans now known and the first to be reported from the Precambrian, seems to suggest that heterotrophic protists (or primitive metaozoans) were extant at least as early as about 750 +/- 100 million years ago.