从海洋生物鲎血中提取超氧化物歧化酶及其抗菌作用的研究

目的 综合利用鲎试剂生产的废料血浆提取超氧化物歧化酶 (Superoxide dismutase,SOD),探讨鲎血SOD对耐甲氧西林金色葡萄球菌(MRSA)、对甲氧西林敏感金色葡萄球菌(MSSA)、野生型绿脓杆菌(PAO1)、大肠杆菌(E.coli)的抑菌作用.方法 采用离心分离、丙酮沉淀、热变性去杂蛋白的方法从生产鲎试剂废料血浆中提取SOD,然后把SOD加入菌液培养,24 h后观察结果.结果 SOD对耐甲氧西林金色葡萄球菌、对甲氧西林敏感金色葡萄球菌、野生型绿脓杆菌、大肠杆菌的最低抑菌浓度分别为20.02,40.05,20.02,20.02 μg/ml.结论 本方法可成功地从生产鲎试剂废料血浆中提取得到SOD粗品,实验表明鲎血SOD具有抗菌作用.     

长江中青鱼的生长速度

青鱼是我国四大家鱼之一,在淡水捕捞业和养鱼业上都占有一定的地位。       

药蒲公英(Taraxacum officinale Weber)耐1.5% NaCl变异体的筛选及特性分析

为提高药蒲公英的耐盐性, 用20~30 d大小的药蒲公英叶片诱导愈伤, 获得的愈伤以NaCl作为选择因子, 用直接筛选的方法, 每3周进行一次继代培养, 经3个月继代筛选获得了耐1.5% NaCl的药蒲公英愈伤组织, 将耐1.5% NaCl的药蒲公英愈伤组织接种在分化培养基上分化出芽, 之后将再生芽转接到生根培养基中进行生根培养, 经4个月得到了12株耐1.5% NaCl的药蒲公英再生植株。与野生型相比, 耐盐植株叶片宽大、叶柄粗短、叶表面覆盖白色细毛, 根粗壮较短, 花茎中部具2 cm左右的苞叶。RAPD(Random amplified polymorphic DNA , 随机扩增的多态性DNA)和SDS-PAGE检测表明, 耐盐植株与对照植株在DNA及蛋白水平上均存在明显差异。1.5% NaCl处理后, 与普通再生植株相比, 耐盐株系的抗氧化酶活性明显提高, 脯氨酸含量上升幅度更为显著, 而丙二醛(MDA)含量降低, 其主要药用成分黄酮的含量显著增加。这些结果说明耐盐植株的抗氧化防御能力明显增强。以上结果表明耐1.5% NaCl的药蒲公英再生植株为耐1.5% NaCl药蒲公英变异体, 这些耐盐变异体有望成为抗盐耐海水蔬菜家族的新成员。同时, 这些耐盐变异体植株比普通植株具有更高的医用商业价值。耐1.5% NaCl的药蒲公英再生变异体遗传稳定性的研究正在进行中。     

miRNA-20a促进卵巢癌细胞OVCAR3的转移

目的检测miRNA．20a对卵巢癌细胞系OVCAR3转移能力的影响。方法通过实时定量RT-PCR验证反义寡核苷酸与小干扰RNA封闭与过表达的效果,然后利用MTF、软琼脂集落形成和transwell侵袭实验检测封闭和过表达miRNA．20a对OVCAR3细胞增殖及转移能力的影响。结果封闭内源性miRNA-20a后,细胞活性基本不受影响,但集落形成能力和细胞的转移能力明显降低。过表达miRNA-20a后,细胞活性基本不受影响,但集落形成能力和细胞的转移能力明显升高。结论miRNA-20a可能参与了卵巢癌细胞OVCAR3的转移。     

水稻蜡质基因第一内含子中g片段上核蛋白因子结合位点的确定

水稻蜡质基因 5’非翻译区中的第一内含子具有增强基因表达的作用 ,本实验室曾检测到该内含子中的一段 171bp长的g片段与水稻未成熟种子核蛋白存在特异性结合。本文进一步用凝胶滞后实验和足印实验确定了该核蛋白在g片段上的结合位点位于蜡质基因转录起始点下游 783～ 818bp处 ,该结合位点富含AT碱基 ;Southwesternblot实验测出该蛋白的分子量约为 2 0kD。用硫酸铵分步沉淀和肝素 Sepharose柱层析的方法对这一蛋白进行了初步纯化。还初步检测了此蛋白DNA结合活性对温度的耐受性。以上特征提示它可能属于HMG类DNA结合蛋白     

Association and differentiation of MHC class I and II polymorphic Alu insertions and HLA-A, -B, -C and -DRB1 alleles in the Chinese Han population

In order to investigate the polymorphism of Alu insertions (POALINs) in the HLA region, we genotyped ten Alu loci (AluMICB, AluTF, AluHJ, AluHG, AluHF in the HLA class I region and AluDPB2, AluDQA2, AluDQA1, AluDRB1, AluORF10 in the HLA class II region) to determine their allele frequencies and associations with the HLA-A, HLA-B, HLA-C and HLA-DRB1 genes in the Chinese Han population. Our results showed the ten-loci POALINs varied in frequency between 0.003 and 0.425. By comparing the data of the ten-loci POALIN in Chinese Han with Japanese and Caucasian data, marked differences were observed between the three ethnic groups at the allelic or haplotypic levels. Each POALIN was in significant linkage disequilibrium with a variety of HLA-A, -B, -C and -DRB1 alleles, and was associated with a variety of HLA-A, -B, -C and -DRB1 allele in Chinese Han. This comparative study of multilocus POALINs in the HLA class I and II regions of the Chinese Han population shows that POALINs alone or as haplotypes together with the HLA class I and II alleles are informative genetic markers for the identification of HLA class I and II allele and variations, such as crossing over events within the same and/or different populations.     

Molecular Epidemiology and Clinical Characteristics of Drug-Resistant Mycobacterium tuberculosis in a Tuberculosis Referral Hospital in China

Background

Despite the large number of drug-resistant tuberculosis (TB) cases in China, few studies have comprehensively analyzed the drug resistance-associated gene mutations and genotypes in relation to the clinical characteristics of M. tuberculosis (Mtb) isolates.

Methodology/Principal Findings

We thus analyzed the phenotypic and genotypic drug resistance profiles of 115 Mtb clinical isolates recovered from a tuberculosis referral hospital in Beijing, China. We also performed genotyping by 28 loci MIRU-VNTR analysis. Socio-demographic and clinical data were retrieved from medical records and analyzed. In total, 78 types of mutations (including 42 previously reported and 36 newly identified ones) were identified in 115 Mtb clinical isolates. There was significant correlation between phenotypic and genotypic drug resistance rates for first-line anti-TB drugs (P<0.001). Genotyping revealed 101 MIRU-VNTR types, with 20 isolates (17.4%) being clustered and 95 isolates (82.6%) having unique genotypes. Higher proportion of re-treatment cases was observed among patients with clustered isolates than those with unique MIRU-VNTR genotypes (75.0% vs. 41.1%). Moreover, clinical epidemiological links were identified among patients infected by Mtb strains belonging to the same clusters, suggesting a potential of transmission among patients.

Conclusions/Significance

Our study provided information on novel potential drug resistance-associated mutations in Mtb. In addition, the genotyping data from our study suggested that enforcement of the implementation of genotyping in diagnostic routines would provide important information for better monitor and control of TB transmission.     

太子参花药发育及精细胞分离

太子参花药壁发育为基本型,腺质绒毡层。小孢子母细胞减数分裂为同时型,小孢子四分体为四面体型,成熟花粉具两个精细胞,为3胞花粉。在花粉表面具散孔,孔数22—30个,均匀分布于花粉粒表面上。花粉在10％甘露醇或15％蔗糖溶液中可直接爆破,精细胞易被释放并散开,通过显微操作仪可收集到一定数目的精细胞。FDA染色荧光显示释放出来的精细胞活力可维持25—50min。花粉在舍O．03％CaCl2、0．01％H3803、0．01％KH2P04和20％PEG、pH5．8的培养液中2—5min即萌发花粉管．花粉管生长2h可达815μm。一般花粉管伸长500—600μm时,一对精细胞才进入花粉管。DAPI染色后荧光观察．可观察到精细胞和营养细胞核在花粉管中的移动状况。爆破花粉管后可释放出一对精细胞。     

作物数量遗传学基础 二、遗传力及其估算

两栖类染色体的研究,过去多使用以生殖 细胞和端蚌尾部上皮细胞为材料的水低渗压片 法^[6]。然而,生殖细胞和峪蚌组织受季节的限 制颇大,所得的中期分裂相亦不甚多。随着 低等脊稚动物组织培养技术^[1,2]与血液培养技 术^[3]的发展,近年来已更多的使用离体培养的 细胞来进行研究。     

Human immunodeficiency virus types 1 and 2 and simian immunodeficiency virus Nef use distinct but overlapping target sites for downregulation of cell surface CD4.

Although the Nef proteins encoded by human immunodeficiency virus type 1 (HIV-1) and simian immuno-deficiency virus (SIV) are known to induce the efficient internalization and degradation of cell surface CD4, it remains unclear whether this process involves a direct interaction between Nef and CD4. Here, we report that CD4 downregulation by HIV-1 and SIV Nef requires distinct but overlapping target sites within the CD4 intracytoplasmic domain. In particular, mutation of a glutamic acid residue located at CD4 residue 405 or of arginine and methionine residues located, respectively, at residue 406 and 407 results in a mutant CD4 protein that is efficiently downregulated by HIV-1 Nef but refractory to downregulation by SIV Nef. However, both HIV-1 and SIV Nef require an isoleucine located at residue 410 and the dileucine motif found at CD4 residues 413 and 414. CD4 downregulation induced by the Nef protein encoded by HIV-2 is shown to require a CD4 target sequence that is similar to, but distinct from, that observed with SIV Nef. These data explain the previous finding that the murine CD4 protein, which has an alanine at residue 405, is refractory to downregulation by SIV, but not HIV-1, Nef (J. L. Foster, S.J. Anderson, A. L. B. Frazier, and J. V. Garcia, Virology 201:373-379, 1994). In addition, these observations provide strong genetic support for the hypothesis that the Nef-mediated downregulation of cell surface CD4 requires a direct Nef-CD4 interaction.