金黄色葡萄球菌中PVL基因与噬菌体DNA的同源性

为了探讨金黄色葡萄球菌PVL基因与噬菌体的相关性,从4株含有PVL基因的菌株中分离出DNA,用HindⅢ或EcoRI酶切后,分别与PVL和Lukm-lukF-PV探针进行Southern印迹杂交,以及对含有PVL基因及其下游区域的片段克隆、测序和同源性分析。结果表明3株菌的PVL基因及其下游区域的序列与V8菌株噬菌体ΦPVL的PVL基因及其下游噬菌体stt site的序列一致。另一菌株的LukM-lukF-PV基因与ΦPVL,的PVL基因有78％的同源性,并且在LukM-lukF-PV基因的下游区域发现与金黄色葡萄球菌噬菌体Φ11整合位点有98％同源性的序列,根据PVL基因存在于噬菌体的基因组上,推测可通过噬菌体转导在金黄色葡萄球菌中传播。     

红曲AS 3．3491葡萄糖淀粉酶生物合成的调节

红曲 Monascus AS 3.978的变异株 AS 3.3491曾是葡萄糖淀粉酶的工业生产菌株。本文报告的实验结果表明该菌株的葡萄糖淀粉酶是构成酶,它的形成受降解物阻遏的调控。AS 3.3491葡萄糖淀粉酶形成的时间过程属典型的产物形成与生长呈负相关的类型,即菌丝体生长停止后酶才开始大量形成。从培养基中除去过量易利用碳源可使葡萄糖淀粉酶形成消阻遏。各种可利用碳源以低浓度分别加到洗涤的菌丝体悬浮液中都能促进葡萄糖淀粉酶的形成,其中蜜二糖和半乳糖的促进作用最甚。在限制生长的条件下,即向洗涤菌丝悬浮液连续缓慢供给低浓度葡萄糖,则在整个培养过程中,葡萄糖淀粉酶的活力稳步上升,不需要任何诱导物,并且比酶形成值达到蜜二糖培养基的水平。因此,高浓度葡萄糖阻遏葡萄糖淀粉酶形成,但低浓度葡萄糖却促进酶的形成。     

金黄色葡萄球菌对小鼠产生一氧化氮及一氧化氮合酶的影响

目的 :探讨金黄色葡萄球菌对小鼠产生一氧化氮 (NO)及一氧化氮合酶 (NOS)的影响 ,以进一步研究 NO及 NOS在抗感染免疫中的作用。方法 :将不同剂量的金黄色葡萄球菌注入小鼠腹腔 ,10 d后取小鼠血清和腹腔巨噬细胞培养上清 ,用硝酸还原酶法检测其 NO的含量 ,同时测定血清中 NOS的水平及抗金黄色葡萄球菌抗体的效价。结果 :金黄色葡萄球菌注射小鼠后 ,血清中 NO及 NOS的水平明显高于对照组 (P<0 .0 1) ,各组间两两比较亦差异有显著性 (P<0 .0 1)。腹腔巨噬细胞培养上清 NO的水平明显高于对照组 (P<0 .0 1) ,但不同剂量实验组之间差异无显著性 (P>0 .0 5)。结论 :金黄色葡萄球菌可引起小鼠血清中 NO、NOS升高 ,NO及 NOS可能在抗微生物感染免疫中起着重要的作用     

THE REGULATION OF RNA SYNTHESIS AND PROCESSING IN THE NUCLEOLUS DURING INHIBITION OF PROTEIN SYNTHESIS

The effect of protein synthesis inhibition by cycloheximide on nucleolar RNA synthesis and processing has been studied in HeLa cells. Synthesis of 45S RNA precursor falls rapidly after administration of the drug. However, the nucleolar content of 45S RNA remains relatively constant for at least 1 hr because the time required for cleavage of the precursor molecule into its products is lengthened after treatment with cycloheximide. The efficiency of transformation of 45S RNA to 32S RNA remains constant with approximately one molecule of the 32S RNA produced for each cleavage of a molecule of 45S RNA. However, shortly after the cessation of protein synthesis the formation of 18S RNA becomes abortive. The amount of 32S RNA present in the nucleolus remains relatively constant. After long periods of protein synthesis inhibition the 28S RNA continues to be synthesized and exported to the cytoplasm but at a greatly reduced rate. When the protein synthesis inhibitor is removed, a prompt, although partial, recovery in the synthesis rate of 45S RNA occurs. The various aspects of RNA synthesis regulation and processing are discussed.     

性病患者金黄色葡萄球菌感染耐药性调查

目的：分析和探讨性病后泌尿生殖系统金黄色葡萄球菌及耐甲氧西林金黄色葡萄球菌(MRSA)感染及其对各类抗生素的耐药性,以协助指导临床合理用药。方法：采用常规培养鉴定方法和1999年美国NCCLS药敏试验纸片扩散法检测泌尿生殖系标本中金黄色葡萄球菌、MRSA分离率及其对抗生素的敏感性。结果：427例标本共分离出金黄色葡萄球菌236株,其中MRSA占43．6％。金黄色葡萄球菌对常用16种抗生素的耐药率小于20％有万古霉素、呋喃坦啶、阿米卡星、利福平。MRSA对上述外的抗生素均有不同程度的耐药,且耐药性均高于MRSS．呈多重耐药。结论：金黄色葡萄球菌在性病泌尿系统感染占首位,这些菌株对各类抗生素有较高的耐药性,且呈多重耐药．应密切关注MRSA流行和播散。     

REGULATION OF PROTEIN SYNTHESIS IN THE VENOM GLAND OF VIPERID SNAKES

Morphological changes in the venom gland of V. ammodytes were studied after the removal of the venom from the gland lumina (milking) It was found that the height of the secretory cells was changed during the secretory cycle. The patterns of the rough endoplasmic reticulum and of the Golgi complex were changed as well Milking induced an increased incorporation of [¹⁴C]amino acids into total and venom proteins In V ammodytes, during the first day after milking, 25% of the total counts in protein were precipitable by anti-venom serum, while at 8 days, 80% of the proteins synthesized were venom proteins At this stage, the incorporation was 10- and 20-fold that of unmilked glands for total and venom proteins, respectively. Venom was accumulated (secreted) in the gland lumina of V. ammodytes at a relatively high rate up to 2 wk after milking and leveled off afterwards. Intact glands and gland slices of V ammodytes and V palaestinae, taken from snakes a few days after milking, incorporated [¹⁴C]amino acids into proteins in vitro at a rate higher than that of unmilked glands. The activity of two exportable enzymes (phosphodiesterase and benzoyl arginyl ethyl esterase) was assayed in gland homogenates of V. ammodytes. It was found that 2–3 wk after milking, the intracellular level of these enzymes was up to 2-fold that of unmilked glands.