伤寒Vi多糖菌苗免疫血清的LPS抗体测定

以肠炎沙门氏菌脂多糖为抗原,用酶标法测定Ｖｉ多糖菌苗免疫血清的抗ＬＰＳ抗体。各Ｖｉ多糖菌苗组免疫后１月,６月的抗ＬＰＳ水平均显著高于免前（Ｐ＜０．０００１）,对照组无显著差异（ｐ＞０．１）。两３０μｇ菌苗组抗ＬＰＳ阳转率均约为１５％。提纯Ｖｉ多糖菌苗所含的微量伤寒ＬＰＳ,也可能为接种者提供一定的保护作用。     

浙江西门岛海洋特别保护区大型底栖动物功能群特征及其与环境的关系

为研究浙江西门岛海洋特别保护区大型底栖动物功能群的变化规律及其与环境因子的关系,作者分别于2010年4月(春季)、11月(秋季),2011年8月(夏季)和2012年2月(冬季)进行了4个航次的大型底栖动物调查,共鉴定出大型底栖动物78种,根据其食性类型划分为浮游生物食者、植食者、肉食者、杂食者、碎屑食者5种功能群.各功能群平均密度从高到低依次为浮游生物食者＞肉食者＞植食者＞碎屑食者＞杂食者,平均生物量从高到低依次为浮游生物食者＞碎屑食者＞肉食者＞杂食者＞植食者.单因素方差分析结果表明,大型底栖动物各功能群的密度和生物量季节间均无显著性差异.典范对应分析结果表明,影响大型底栖动物功能群的主要环境因子包括温度、溶解氧、溶解态无机磷和表层沉积物的中值粒径,排序轴对功能群-环境关系的贡献率计算结果表明环境变量可以较好地解释功能群的变化情况.     

Inhibition of selectin-mediated cell adhesion and prevention of acute inflammation by nonanticoagulant sulfated saccharides. Studies with carboxyl-reduced and sulfated heparin and with trestatin a sulfate

Selectins play a major role in the inflammatory reaction by initiating neutrophil attachment to activated vascular endothelium. Some heparin preparations can interact with L- and P-selectin; however, the determinants required for inhibiting selectin-mediated cell adhesion have not yet been characterized. We now report that carboxyl-reduced and sulfated heparin (prepared by chemical modifications of porcine intestinal mucosal heparin leading to the replacement of carboxylates by O-sulfate groups) and trestatin A sulfate (obtained by sulfation of trestatin A, a non-uronic pseudo-nonasaccharide extracted from Streptomyces dimorphogenes) exhibit strong anti-P-selectin and anti-L-selectin activity while lacking antithrombin-mediated anticoagulant activity. In vitro experiments revealed that both compounds inhibited P-selectin- and L-selectin-mediated cell adhesion under laminar flow conditions. Moreover, carboxyl-reduced and sulfated heparin and trestatin A sulfate were also active in vivo, as assessed by experiments showing 1) that microinfusion of trestatin A sulfate reduced by 96% leukocyte rolling along rat mesenteric postcapillary venules and 2) that both compounds inhibited (by 58-81%) neutrophil migration into thioglycollate-inflamed peritoneum of BALB/c mice. These results indicate that nonanticoagulant sulfated saccharides targeted at P-selectin and L-selectin may have therapeutic potential in inflammatory disorders.     

P-Selectin-mediated acute inflammation can be blocked by chemically modified heparin, RO-heparin

Selectins are carbohydrate-binding cell adhesion molecules that play a major role in the initiation of inflammatory responses. Heparin can bind to P-selectin, and its anti-inflammatory property is mainly due to inhibition of P-selectin. However, the strong anticoagulant activity of heparin limits its clinical use. We prepared periodate-oxidized, borohydride-reduced heparin (RO-heparin) by chemical modification and tested its anticoagulant and anti-inflammatory activities. Activated partial thromboplastin time (aPTT) assays showed that, compared with heparin, RO-heparin had greatly reduced anticoagulant activity. Intravenous administration of this compound led to reduction in the peritoneal infiltration of neutrophils in a mouse acute inflammation model. In vitro cell adhesion experiments demonstrated that the effect of RO-heparin on inflammatory responses was mainly due to inhibiting the interaction of P-selectin with its ligands. These results indicate that RO-heparin may be a safer treatment for inflammation than heparin, especially when selectin is targeted.     

Effects of <Emphasis Type="Italic">TFAR19</Emphasis> gene on the growth and biorheological properties of mouse erythroleukemia cell line MEL

Using the method of gene transfection with liposome, we obtained the mouse erythroleukemia cell line MEL-TF19, which stably carries TFAR19, a novel apoptosis-related gene. The expression of TFAR19 was detected by Western blot. Growth curve and flow cytometry analysis showed that after being transfected with TFAR19 gene, the growth of MEL-TF19 is suppressed and its apoptosis is accelerated because of the serum deprivation. Our biorheological study indicated that in the apoptotic process, compared with MEL cells, MEL-TF19 cells exhibit larger osmotic fragility, lower cell surface charge density, increased elastic modulus K1 which is inversely proportional to cells' maximal deformation ability, obviouslydiminished surface viscosity μ, with elastic modulus K2 having no distinct changes. The above results provided some bases for recognizing the function of TFAR19 completely from the viewpoint of biorheology.     

Characterization of humoral responses in mice immunized with plasmid DNAs encoding SARS-CoV spike gene fragments

The immunological characteristics of SARS-CoV spike protein were investigated by administering mice with plasmids encoding various S gene fragments. We showed that the secreting forms of S1, S2 subunits and the N-terminus of S1 subunit (residues 18-495) were capable of eliciting SARS-CoV specific antibodies and the region immediate to N-terminus of matured S1 protein contained an important immunogenic determinant for elicitation of SARS-CoV specific antibodies. In addition, mice immunized with plasmids encoding S1 fragment developed a Th1-mediated antibody isotype switching. Another interesting finding was that mouse antibodies elicited separately by plasmids encoding S1 and S2 subunits cooperatively neutralized SARS-CoV but neither the S1 nor S2 specific antibodies did, suggesting the possible role of both S1 and S2 subunits in host cell docking and entry. These results provide insights into understanding the immunological characteristics of spike protein and the development of subunit vaccines against SARS-CoV.     

Identification of a neutralization epitope on the envelope gp46 antigen of human T cell leukemia virus type I and induction of neutralizing antibody by peptide immunization.

We have generated a number of mAb against various epitopes on the external envelope glycoprotein, gp46, of human T cell leukemia virus type I (HTLV-I) from a WKA rat immunized with a recombinant vaccinia virus containing the HTLV-I env gene. Among these mAb, one group of mAb, represented by a mAb designated LAT-27, could neutralize the infectivity of HTLV-I, as determined by a HTLV-I-mediated cell fusion inhibition assay. LAT-27 also interfered with transformation of normal T lymphocytes by HTLV-I in vitro. An antibody-binding assay using overlapping synthetic oligopeptides showed that LAT-27 bound specifically to 10-mer peptides that contained the gp46 amino acid sequence 191-196 (Leu-Pro-His-Ser-Asn-Leu). Antibodies from HTLV-I+ humans interfered with the binding of LAT-27 to gp46 Ag. Sera from rabbits immunized with a LAT-27-reactive peptide, 190-199, conjugated with OVA, but not sera from OVA-immunized rabbits, reacted with gp46 Ag and neutralized infectivity of HTLV-I. These results show that the HTLV-I neutralization epitope recognized by LAT-27 locates to the gp46 amino acids 191-196, and that immunization with a peptide containing the LAT-27 epitope can elicit an HTLV-I neutralizing antibody response.     

Genotype-environment interaction for quantitative trait loci affecting life span in Drosophila melanogaster

The nature of genetic variation for Drosophila longevity in a population of recombinant inbred lines was investigated by estimating quantitative genetic parameters and mapping quantitative trait loci (QTL) for adult life span in five environments: standard culture conditions, high and low temperature, and heat-shock and starvation stress. There was highly significant genetic variation for life span within each sex and environment. In the analysis of variance of life span pooled over sexes and environments, however, the significant genetic variation appeared in the genotype x sex and genotype x environment interaction terms. The genetic correlation of longevity across the sexes and environments was not significantly different from zero in these lines. We estimated map positions and effects of QTL affecting life span by linkage to highly polymorphic roo transposable element markers, using a multiple-trait composite interval mapping procedure. A minimum of 17 QTL were detected; all were sex and/or environment-specific. Ten of the QTL had sexually antagonistic or antagonistic pleiotropic effects in different environments. These data provide support for the pleiotropy theory of senescence and the hypothesis that variation for longevity might be maintained by opposing selection pressures in males and females and variable environments. Further work is necessary to assess the generality of these results, using different strains, to determine heterozygous effects and to map the life span QTL to the level of genetic loci.