gamma-Interferon induced by S. aureus protein A augments natural killing and ADCC

Staphylococcus aureus produces a protein identified as protein A (SpA) with a molecular weight of 41,000 (ref. 1) which binds to the Fc region of many types of mammalian IgG2, activates complement, blocks opsonins and is both chemotactic and mitogenic. SpA has been used for various immunological purposes including removal of immune complexes, arming effector cells with antibody, distinguishing between antibody-dependent cell-mediated cytotoxicity (ADCC) and natural killing (NK), and exerting anti-tumor activity. We have now demonstrated that SpA induces the production of gamma interferon (IFN-gamma) in nonadherent, T lymphocyte-depleted (E-), Fc receptor-bearing (FcR+) human peripheral blood lymphocytes. Our data also suggest that IFN-gamma is a potent stimulator of both NK and ADCC activity.     

RNASEL Arg462Gln variant is implicated in up to 13% of prostate cancer cases

RNASEL (encoding ribonuclease L) has recently been proposed as a candidate for the hereditary prostate cancer (HPC1) gene. We determined that the RNASEL variant Arg462Gln has three times less enzymatic activity than the wildtype and is significantly associated with prostate cancer risk (P = 0.007). At least one copy of the mutated allele that causes this substitution is carried by nearly 60% of the men in our study. Men that are heterozygous with respect to the mutated allele have 50% greater risk of prostate cancer than non-carriers, and homozygotes have more than double the risk.     

富营养化水体中的溶源性浮游细菌分布与环境因子的关系

使用非侵害性根吸收硝酸盐检测系统,在较低NO3-浓度下,测定10 m mol/L的蔗糖、葡萄糖、果糖、半乳糖、棉子糖、D-甘露醇、甘露糖、阿拉伯糖、乳糖对水稻品种"汕优63"硝酸盐吸收的影响,以10 min为间隔连续测定4 h,结果表明:加入蔗糖后对水稻硝酸盐的吸收有显著的、立即的、持续的促进作用,与加入蔗糖前相比,硝酸盐净吸收率上升了298%,葡萄糖、半乳糖、果糖、棉子糖对水稻硝酸盐的吸收亦有明显的促进作用,上升幅度140%～223%;乳糖、D-甘露醇、阿拉伯糖无明显影响;甘露糖则有抑制作用.蔗糖可能足作为主要的信号分子参与植物硝酸盐吸收的正反馈调控.