Characterization of <Emphasis Type="Italic">Streptococcus mutans</Emphasis> diversity by determining restriction fragment-length polymorphisms of the <Emphasis Type="Italic">gtfB</Emphasis> gene of isolates from 5-year-old children and their mothers

The diversity between Streptococcus mutans clinical isolates from 5-year-old children and their mothers in two South African ethnic groups was investigated. The gtfB gene encoding for glucosyltransferase (EC 2.4.1.5), an enzyme responsible for the synthesis of extracellular polysaccharides was characterized by PCR-RFLP with HaeIII restriction enzyme digestion. Forty-seven children were examined for dental caries and 128 S. mutans clinical isolates cultured from samples of their saliva and plaque and from the saliva of their mothers. Thirty-three children had active caries (70%) and the remainder (n = 14) were caries-free. Caries prevalence was significantly different (p = 0.02) between black African and coloured children, but no differences were found between gtfB amplitypes by caries or ethnic grouping. Thirty-four (27%) of the S. mutans clinical isolates investigated did not ferment melibiose. Melibiose-negative phenotypes (n = 10) isolated from four families showed gtfB RFLP patterns identical to each other. Mothers and children harboured between one and three amplitypes. GtfB amplitypes were identical in 17 families (17/47), of which nine only were identical to S. mutans reference strains. The percentage match between S. mutans amplitype from mothers and their children was low (13%) in the caries-free group compared to children with caries (44%). RFLP analysis of the gtfB gene showed the diversity of S. mutans genotypes within two South African populations that were acquired from mothers and other sources.     

High-yielding plasmid extraction method from acidophilic heterotrophic bacteria of the genus Acidiphilium

Plasmid yield from Acidiphilium strains always had been poor following various standard methods. We adopted some simple modifications in the alkaline lysis procedure to get a better yield of plasmid from these bacteria. An approximately 10- to 20-fold increase in the plasmid yield was achieved when harvested Acidiphilium cells were preincubated 16-20 h at pH 6 in nitrogen-free medium. Another independent approach showed that freezing (-18 to -20 degrees C) of the harvested cells initially and at two subsequent steps in the alkaline lysis procedure of plasmid DNA extraction improved the yield further by 1.5- to 3-fold. The combination of these changes yielded at least 15- to 30-fold more plasmid from various Acidiphilium strains as compared with standard methods.     

葡萄蛋白质组学研究进展

人类基因组计划的完成标志着生命科学已进入后基因组时代,蛋白质组学的研究被提升到了前所未有的高度,蛋白质组学旨在阐明基因组所表达的真正执行生命活动的全部蛋白质的表达规律和生物功能。伴随葡萄基因组测序工作的完成,有关葡萄蛋白质组学的研究迅速发展。对近年来蛋白质组学在葡萄上的研究进行了综述,内容主要包括:葡萄蛋白质样品的提取制备,葡萄果实发育和品质形成过程中蛋白质组的变化,葡萄果皮、细胞壁、质膜等特定组织材料的蛋白质组研究,及蛋白质组学在葡萄逆境胁迫、体细胞胚的发生等方面的研究,并对葡萄蛋白质组学的发展趋势进行了展望。     

金双歧对早产儿坏死性小肠结肠炎预防作用的研究

目的探讨微生态制剂金双歧对早产儿早期应用是否能起到预防坏死性小肠结肠炎(NEC)的发生.方法对2000年1月～2002年12月入住青海省红十字医院新生儿,符合早产儿诊断126例,随机分治疗组、对照组.治疗组在治疗原发病的基础上,24 h内即加用双歧杆菌三联片(商品名:金双歧)口服或鼻饲,对照组只治疗原发病,观察2周内NEC的发生情况.结果治疗组62例,发生NEC 8例,对照组64例,发生NEC 20例.结论及早对早产儿补充微生态制剂,使其占据肠黏膜表面,作为生物屏障构成肠道的定植阻力,阻止致病菌入侵,或刺激机体免疫系统,增强机体免疫功能,从而起到降低早产儿NEC的发生.     

The influence of nest site selection on the population dynamics of Africanized honey bees in an urban landscape

Urban landscapes provide habitat for many species, including domesticated and feral honey bees, Apis mellifera L. (Hymenoptera: Apidae). With recent losses of managed honey bee colonies, there is increasing interest in feral honey bee colonies and their potential contribution to pollination services in agricultural, natural, and urban settings. However, in some regions the feral honey bee population consists primarily of Africanized honey bees. Africanized honey bees (AHB) are hybrids between European honey bees and the African honey bee, Apis mellifera scutellataLepeletier, and have generated economic, ecological, and human health concerns because of their aggressive behavior. In this study, we used two long‐term datasets (7–10 years) detailing the spatial and temporal distribution of AHB colonies in Tucson, AZ, USA, where feral colonies occupy a variety of cavities including water meter boxes. A stage‐structured matrix model was used to elucidate the implications of nest site selection and the effects of colony terminations on the structure and dynamics of the AHB population. Our results suggest that Tucson's AHB population is driven by a relatively small number of ‘source’ colonies that escape termination (ca. 0.165 colonies per km² or 125 colonies in total), although immigrating swarms and absconding colonies from the surrounding area may have also contributed to the stability of the Tucson AHB population. Furthermore, the structure of the population has likely been impacted by the number and spatial distribution of water meter boxes across the city. The study provides an example of how urban wildlife populations are driven by interactions among landscape structure, human management, and behavioral traits conferred by an invasive genotype.     

牛河梁红山文化人群龋齿的统计与分析

本文通过对牛河梁遗址出土的31例红山文化时期人类牙齿龋病的统计与分析, 获知: 1)牛河梁遗址男女两性的患龋率、龋齿率没有明显的性别差异; 2)他们的患龋率和龋齿率有随年龄增长逐步增高的趋势; 3)上颌的龋齿罹患率高于下颌; 4)龋齿的发生主要集中在臼齿,且以咬合面部位为主; 5)他们的患龋率和龋齿率均较低。牛河梁红山文化人群相对偏低的龋齿率可能暗示出他们的经济生活方式还处在以采集狩猎为主体的模式中, 农耕经济可能处于较低层次的状态。     

Ultrastructure of Microvillar Coelomocytes from the Trunk Coelom of Thysanocardia nigra Ikeda, 1904 (Sipuncula) from the Sea of Japan

This research is part of a study on the ultrastructure of coelomocytes and cellular complexes from the body cavity of sipunculans. New free-swimming elements called microvillar cells in the trunk coelom of Thysanocardia nigra Ikeda, 1904 are examined using transmission electron microscopy. The cell harbors a giant vesicle filled with a fibrous matrix and rosettes of minute osmiophilous granules. The nucleus is peripheral, and a few cell organelles are situated between the cell membrane and the vesicular membrane. The cell membrane bears numerous microvilli with enlarged apical points. Numerous small microvillar vesicles swimming in the coelomic fluid separate from the microvillar cells. The functional morphology of coelomocytes and cellular complexes is discussed.Original Russian Text Copyright © 2005 by Biologiya Morya, Maiorova, Adrianov.     

抗果蝇Dxl6蛋白抗体的制备及特异性分析

为了研究果蝇中SR蛋白家族新成员Dxl6的功能,通过RT-PCR得到Dxl6的全长cDNA,并根据Dxl6基因产物的功能区,分别将Dxl6中间区域（Dxl6 middle part, Dxl6MP）、Dxl6 C末端RS结构域（Dxl6 RS domain, Dxl6RSD）序列亚克隆至pGEX-4T-1(His)6C 及pET32a 表达载体中,表达和纯化获得融合蛋白。用纯化的融合蛋白GST-Dxl6RSD-His和GST-Dxl6MP-His免疫家兔,分别得到抗Dxl6RSD和抗Dxl6MP两种抗体。WESTERN BLOT结果显示两种抗体能特异地识别在原核表达系统内表达的抗原,抗Dxl6RSD的抗体对果蝇组织中的Dxl6具有较高的特异性。Abstract: In order to study the function of Dxl6 which is a novel member of SR protein family, its cDNA was cloned by RT-PCR, and the sequences of its RS domain and its middle part were subcloned into two fusion express vectors, pGEX-4T-1His（6）C and pET32a. After expressing in E.coli BL21, the truncated proteins of Dxl6 RS domain part and Dxl6 middle part in pGEX-4T-1His（6）C were purified and used to immunize rabbits. Purified antibodies against the RS domain and Dxl6 middle part were obtained by affinity chromatography with the expressed products of Dxl6 RS domain part and Dxl6 middle part in pET32a, respectively. The result shows the antibody against Dxl6 RS domain has a good specificity to Dxl6 in Drosophila larvae by Western blot analysis.