少动鞘氨醇单胞菌引起小儿败血症合并脑膜炎1例

本文报道1例罕见的由少动鞘氨醇单胞菌引起的小儿败血症合并脑膜炎。该患儿突发高热起病,伴有皮肤散在瘀点。根据实验室微生物分离和鉴定,确诊为少动鞘氨醇单胞菌引起的败血症;同时根据脑脊液生化常规结果,诊断为合并细菌性脑膜炎。少动鞘氨醇单胞菌引起的小儿败血症合并脑膜炎属罕见病例,且该患儿有类似流行性脑脊髓膜炎的症状,易被误诊为春季小儿流行性脑脊髓膜炎,需引起临床及实验室工作人员的重视。     

鞘氨醇单胞菌的研究进展

鞘氨醇单胞菌(Sphingomonas)不仅细胞膜含有比脂多糖更疏水的鞘糖脂,而且具有高效的代谢调控机制和基因调控能力,使其在威兰胶合成、环境修复和促进植物生长等方面具有巨大的应用潜力。目前国内在鞘氨醇单胞菌代谢机制方面的研究尚无新突破。本文主要综述了鞘氨醇单胞菌的系统分类、基因组学、基因调控机制及其应用等方面的研究,从基因层面分析鞘氨醇单胞菌产威兰胶的合成机制,为后续鞘氨醇单胞菌高密度发酵、工业化生产等研究提供理论基础,以便进一步发掘其在生物技术上的应用潜力。     

合成生物聚合物的重要微生物资源-鞘氨醇单胞菌

摘要：鞘氨醇单胞菌属的许多菌株能够合成结冷胶、沃仑胶、迪特胶等多种结构相似,物理性能多样的生物聚合物,统称为鞘氨醇胶。目前,结冷胶已经大规模的生产和应用,由于鞘氨醇单胞菌属的提出仅有十几年的历史,其他种类鞘氨醇胶的研究和开发才刚刚起步。本文综述了鞘氨醇单胞菌属分类研究的最新进展,以及鞘氨醇胶的结构、特性、生物合成途径、分子遗传学和基因工程的研究现状,并对今后的研究重点和方向进行了展望。     

少动鞘脂单胞菌S1胞外多糖发酵工艺条件研究

研究了摇瓶培养条件下少动鞘脂单胞菌引的胞外多糖的发酵工艺。Ｓ１菌的发酵产胶可采用二步发酵法：第一阶段,培养基成分为：蔗糖１０ｇ,ＮＨ_４ＮＯ_３　０．５ｇ,ＫＨ_２ＯＰ_４　０．５ｇ,ＭｎＳＯ_４　０．３ｇ,ＭｇＳＯ_４　０．１ｇ,吐温８０ ０．０２ｇ溶于蒸馏水并定容至１０００ｍＬ,ｐＨ７．２±０．１,温度３３℃～３５℃,高溶氧。第二阶段,发酵 １０～１２ｈ后,补加蔗糖４０ｇ／Ｌ,温度     

LB克隆系统的构建及在鞘氨醇单胞菌基因融合表达中的应用

为摆脱限制性酶切位点不足的限制,构建可灵活改变多基因融合方向的表达载体,基于ⅡS型和ⅡT型限制性内切酶LguⅠ和BbvC Ⅰ设计开发了 LB克隆系统.该克隆系统是以广宿主质粒pBBR1MCS-3为初始载体,利用 PCR的方法,在其多克隆位点区插入LB片段(GCTCTTCCTCAGC)构建得到的.LB片段含Lgu Ⅰ和B...     

鞘氨醇单胞菌TP-3合成新型生物聚合物Ss的发酵条件优化

鞘氨醇单胞菌(Sphingomonas sp.)TP-3能合成一种具有增稠性、假塑性、成凝胶特性和乳化性能的新型生物聚合物Ss。运用单因素实验和均匀设计法对菌株TP-3合成聚合物Ss的发酵条件进行优化, 实验结果表明, 培养基组成为葡萄糖41.2 g/L, 豆饼粉2.0 g/L, NaCl 0.85 g/L, K2HPO4 1.46 g/L, MgSO4 0.12 g/L, MnCl2 0.0075 g/L, FeSO4 0.002 g/L, 初始pH为7.0, 在27°C, 180 r/min的条件下摇床培养60 h, 聚合物Ss的产量达到21.5 g/L。该聚合物生产成本低, 在油田开发中极具应用前景。     

鞘氨醇激酶-磷酸鞘氨醇轴在血管生成相关性疾病中的作用

血管生成是指在原有血管的基础上形成新血管的过程.病理性血管生成是癌症、心血管类疾病和视网膜病变等一系列疾病的标志.1-磷酸鞘氨醇(sphingosine-1-phosphate,S1P)是一种信号脂质,由鞘氨醇激酶(sphingosine kinases,SPHK)合成,通过5种G蛋白偶联受体(sphingosine-...     

鞘氨醇激酶活性测定方法的建立及其初步应用

目的:建立生物样品中鞘氨醇激酶(SPK)活性和1-磷酸鞘氨醇(S1P)含量的测定方法.方法:用Flag标记的SPK基因表达载体转染ECV304细胞,用Western blot方法检测转染后SPK基因的表达,用酶促反应、同住素掺入和薄层层析的方法检测SPK的活性.提取细胞或组织的S1P,碱性磷酸酶消化去除磷酸根,然后利用SPK的催化活性和同位素标记的方法对S1P进行定量.结果:转染基因后细胞的SPK表达明显升高,活性显著增强,细胞内S1P的含量也明显增多.肝细胞生长因子(HGF)刺激能增强ECV304细胞SPK的活性和细胞内S1P水平.结论:建立了SPK活性和S1P含量的测定方法.     

鞘氨醇杆菌的研究进展

鞘氨醇杆菌是一类革兰氏阴性非发酵杆状细菌,很少引起人类感染,它的主要特点是含有大量的细胞膜鞘磷脂。由于其广泛的生态分布与石油降解能力,已引起了环境微生物学者的重视。本综述总结分析了鞘氨醇杆菌的分类学地位及其主要成员的进化亲缘关系,重点阐述了它们的生理生化特征方面的研究进展,最后总结了8个鞘氨醇杆菌的基因组特征,以期为深入研究鞘氨醇杆菌的功能及其泛基因组提供理论指导,并进一步对鞘氨醇杆菌的深入研究进行了展望。     

少动鞘脂单胞菌产结冷胶发酵培养基的响应面法优化

通过单因素试验分析不同碳源、氮源、无机盐对（Sphingomonas paucimobilisFJAT-5627）产胶量的影响,确定最适碳源、氮源、无机盐,并在单因素筛选试验的基础上,利用Box-Benhnken设计和响应面分析法对碳源、氮源和无机盐进行优化,得到少动鞘脂单胞菌产生结冷肢发酵培养基最佳优化组合.实验结果表明,少动鞘脂单胞菌产胶量发酵最适碳源、氮源和无机盐分别为淀粉、豆饼粉和KH₂PO₄.响应面法得到产胶量（Y）与碳源淀粉（x₁）、氮源豆饼粉（x₂）和无机盐KH₂PO₄（x₃）的回归方程为:Y=13.87+0.54x₁+0.22x₂-0.42x₃-3.26x₁²-1.85x₂²-1.51x₃²+0.053x₁x₂+0.067x₁x₃+0.4x₂x₃.优化培养基组合为:淀粉浓度为30g/L,豆饼粉浓度为5 g/L,KH₂PO₄的浓度为0.7g/L,且此组合下少动鞘脂假单胞发酵得到结冷胶可达23.87g/L.     

Degradation of alpha, beta, gamma and delta-hexachlorocyclohexanes by Sphingomonas paucimobilis

Sphingomonas paucimobilis degrades aerobically , , and -hexachlorocyclohexane. With -HCH, complete degradation occurred after 3 days but with and , and with -HCH, 98 and 56 % degradation occurred after 12 and 8 days of incubation, respectively. Pentachlorocyclohexene was formed as the primary metabolite during the degradation of all the HCH isomers. © Rapid Science Ltd. 1998     

The Role of Exopolymers Produced by Sphingomonas paucimobilis in Biofilm Formation and Composition

Exopolymers have been associated with the initial adhesion of bacteria, which is the primary step for biofilm formation. Moreover, the polymeric matrix of biofilms has a considerable influence on some of the most important physical and physiological properties of biofilms. The role of extracellular polymers in biofilm formation was studied using three mutants of Sphingomonas paucimobilis with increasing capabilities for exopolymer production. The physical, biochemical and physiological properties of three different layers of each biofilm were determined. The layers were detached by submitting the biofilm to increasing shear stress. The results revealed that the presence of exopolymers in the growth medium was essential for biofilm formation. The mutant producing the highest amount of exopolymer formed very thick biofilms, while the biofilms formed by the medium exopolymer producer were on average 8 times thinner. The lowest exopolymer producer did not form biofilm. In both types of biofilms, exopolymer density increased with depth, although this tendency was more significant in thinner biofilms. Cell distribution was also more heterogeneous in thinner biofilms, exhibiting a greater accumulation of cells in the inner layers. The thicker biofilms had very low activity in the inner layer. This was related to a high accumulation of proteins and DNA in this layer due to cell lysis and hydrolytic activity. Activity in the thin biofilm was constant throughout its depth, suggesting that there was no nutrient limitation. The production of exopolymers by each cell was constant throughout the depth of the biofilms, although it was greater in the case of the higher producer.     

感染性心内膜炎51例临床分析

目的分析感染性心内膜炎(IE)患者临床特征及疗效,探讨IE的早期诊断及合理治疗。方法回顾性分析2009年1月1日至2010年10月31日收治的51例IE病例的临床资料,分析IE患者的心脏基础疾病情况、血培养、超声心动图改变及治疗效果、预后等。结果 51例IE患者中以无基础疾病(27.45%)及风湿性瓣膜病变后IE(23.50%)最为多见,感染病原体以葡萄球菌属多见(46.88%,15/32),次为链球菌属(28.12%,9/32)。超声心动图检查阳性率高(80.39%),手术治疗21例(41.18%,21/51),51例中共死亡5例。结论 IE的临床特征发生了明显变化,临床需提高认识,多学科合作,使疾病得到恰当治疗处理。     

Differences in dynamics between indigenous and inoculated Sphingomonas paucimobilis strain SS86 in soils

Abstract Survival of γ-HCH-degrading Sphingomonas paucimobilis strain SS86 indigenous or inoculated to soil was examined under laboratory conditions. Strain SS86 inoculated to soil declined to undectectable levels though amendment of soil with γ-HCH or starvation-treatment of the cells enhanced its survivability. About 10³–10⁴ cells/g soil of strain SS86 indigenous to soil survived stably for long periods and was more tolerant to soil treatment by desiccation, percolation, and chloroform-fumigation than inoculated SS86. The haritable micro-pores in soil and/or physiological properties peculiar to the indigenous SS86 were supposed to ensure its good ability to survive by protecting it against protozoan grazing.     

三角孢小囊菌导致的心内膜炎1例

本文报道1例继发于植入心脏起搏器所致的三角孢小囊菌(Microascus trigonosporus)心内膜炎,此菌分离自患者起搏器电极表面的赘生物.赘生物组织病理切片显示大量有隔真菌丝,间生膨大的厚壁孢子.小囊菌系帚霉菌(Scopulariopsis)的有性阶段,广泛存在于自然界.目前国外已有短帚霉菌(Scopula...     

Gellan gum biosynthesis in Sphingomonas paucimobilis ATCC 31461: genes,enzymes and exopolysaccharide production engineering

The commercial gelling agent, gellan, is an extracellular polysaccharide (EPS) produced by Sphingomonas paucimobilis ATCC 31461. In recent years, significant progress in understanding the relationship between gellan structure and properties and elucidation of the biosynthesis and engineering of this recent product of biotechnology has been made. This review focuses on recent advances in this field. Emphasis is given to identification and characterization of genes and enzymes involved, or predicted to be involved, in the gellan biosynthetic pathway, at the level of synthesis of sugar-activated precursors, of the repeat unit assembly and of gellan polymerization and export. Identification of several genes, biochemical characterization of the encoded enzymes and elucidation of crucial steps of the gellan pathway indicate that possibilities now exist for exerting control over gellan production at any of the three levels of its biosynthesis. However, a better knowledge of the poorly understood steps and of the bottlenecks and regulation of the pathway, the characterization of the composition, structure and functional properties of gellan-like polymers produced either by the industrial strain under different culture conditions or by mutants are still required for eventual success of the metabolic engineering of gellan production. Journal of Industrial Microbiology & Biotechnology (2002) 29, 170–176 doi:10.1038/sj.jim.7000266 Received 11 February 2002/ Accepted in revised form 09 April 2002     

Evaluation of rheological properties of the exopolysaccharide of Sphingomonas paucimobilis GS-1 for application in oil exploration

Analysis of an exopolysaccharide of Sphingomonas paucimobilis GS-1 (EPS/GS-1) with respect to its rheological properties, cross-linking ability with chrome alum and performance test at 75 ± 5°C revealed its strong suspending ability, shear thinning property, and thixotrophic nature which are required to impart desirable rheology to drilling mud. The organism fulfilled all the specified requirements and its properties were superior to those of currently-used XC polymer (a xanthan product) for oil drilling applications. However, EPS/GS-1 was unstable in the presence of bentonite at 100 ± 5°C during performance tests, in contrast to XC polymer. Received 14 April 1999/ Accepted in revised form 26 July 1999     

静脉毒瘾者金黄色葡萄球菌性感染性右心内膜炎(附2例报告及文献复习)

本文在国内首次报道２例静脉毒瘾者金黄色葡萄球菌性感染性右心内膜炎（ＳＩＲＥＤ）,其临床特点：①常合并有肝炎病毒感染;②确诊有赖于心脏超声检查发现三尖瓣赘生物、细菌的毒血症状及血培养的结果;③治疗应根据药敏结果选择２至３种敏感的抗生素联用,其剂量应比常规量大２至３倍,疗程６至８周或更长;④有效治疗后,该病预后良好