Unexpected link between lipooligosaccharide biosynthesis and surface protein release in Mycobacterium marinum

The mycobacterial cell envelope is characterized by the presence of a highly impermeable second membrane, which is composed of mycolic acids intercalated with different unusual free lipids, such as lipooligosaccharides (LOS). Transport across this cell envelope requires a dedicated secretion system for extracellular proteins, such as PE_PGRS proteins, which are specific mycobacterial proteins with polymorphic GC-rich sequence (PGRS). In this study, we set out to identify novel components involved in the secretion of PE_PGRS proteins by screening Mycobacterium marinum transposon mutants for secretion defects. Interestingly, most mutants were not affected in secretion but in the release of PE_PGRS proteins from the cell surface. These mutants had insertions in a gene cluster associated with LOS biosynthesis. Lipid analysis of these mutants revealed a role at different stages of LOS biosynthesis for 10 novel genes. Furthermore, we show that regulatory protein WhiB4 is involved in LOS biosynthesis. The absence of the most extended LOS molecule, i.e. LOS-IV, and a concomitant accumulation of LOS-III was already sufficient to reduce the release of PE_PGRS proteins from the mycobacterial cell surface. A similar effect was observed for major surface protein EspE. These results show that the attachment of surface proteins is strongly influenced by the glycolipid composition of the mycobacterial cell envelope. Finally, we tested the virulence of a LOS-IV-deficient mutant in our zebrafish embryo infection model. This mutant showed a marked increase in virulence as compared with the wild-type strain, suggesting that LOS-IV plays a role in the modulation of mycobacterial virulence.     

兽疫链球菌荚膜多糖对免疫抑制鼠的抗氧化和免疫调节活性研究

目的测定部分纯化的兽疫链球菌荚膜多糖（PCP）的抗氧化和免疫调节活性。方法以注射用环磷酰胺（CY）造成免疫抑制鼠模型。结果口服PCP诱导了免疫抑制鼠超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）和过氧化氢酶（CAT）的活性,提高了总抗氧化能力（TAOC）的水平。口服PCP后免疫抑制鼠的胸腺和脾脏指数明显增加,血清溶菌酶活性和迟发型超敏反应（DTH）引起的肿胀率也显著提高。结论 PCP对免疫抑制鼠具有免疫调节功能并改变CY诱导的氧化压力,是一种潜在的抗氧化剂和免疫调节剂。     

百令胶囊联合罗氟司特治疗老年支气管哮喘的效果及对免疫功能的影响

目的:研究百令胶囊联合罗氟司特治疗老年支气管哮喘的效果及对免疫功能的影响。方法:选择2018年3月~2019年3月我院第六派驻门诊部收治的110例老年支气管哮喘患者,随机分为两组,每组各55例。对照组患者口服罗氟司特片,每次500 mg,每天1次。观察组患者联合服用百令胶囊,每次5粒,每天3次。比较两组的临床控制率,治疗前后两组诱导痰中炎症因子、中性粒细胞、呼出气一氧化氮(fractional exhaled nitric oxide,FeNO)水平和免疫功能的变化。结果:治疗后,观察组的临床控制率为70.91%(39/55),明显高于对照组[40.00%(22/55)](P<0.05);两组的CD4+、CD4+/CD8+和CD3+均较治疗前明显升高,且观察组的CD4+、CD4+/CD8+和CD3+明显高于对照组(P<0.05);两组患者诱导痰中中性粒细胞绝对值、中性粒细胞百分比、白细胞介素-4(interleukin-4,IL-4)、FeNO、白细胞介素-17(interleukin-17,IL-17)均较治疗前明显降低(P<0.05),诱导痰中的干扰素-γ(Interferon gamma,IFN-γ)均较治疗前明显升高(P<0.05),且观察组诱导痰中的组中性粒细胞绝对值、中性粒细胞百分比、IL-4、FeNO、IL-17明显低于对照组(P<0.05),诱导痰中的IFN-γ均明显高于对照组(P<0.05)。结论:百令胶囊联合罗氟司特对老年支气管哮喘患者具有显著的疗效,其机制可能与抑制中性粒细胞的激活、调节T淋巴细胞亚群的平衡和抑制相关炎症因子的释放相关。     

金龙胶囊联合化疗治疗晚期非小细胞肺癌临床疗效观察

目的:观察金龙胶囊联合化疗与单纯化疗对晚期肺小细胞癌患者的疗效、生活质量等因素的影响。方法:将99例患有晚期非小细胞肺癌患者随机分为两组:治疗组,在NP化疗方案基础上加服金龙胶囊治疗;对照组,单纯接受NP方案化疗。对99例患者追踪2个月,观察并比较患者的疗效、体质量、生活质量、毒副反应等方面的差异。结果:在NP化疗方案基础上加服金龙胶囊治疗在患者疗效评价方面与单纯NP方案化疗相比不具有统计学差异(P>0.05);在提高患者体质量、改善患者临床症状和生活质量等方面均优于单纯NP方案化疗(P<0.05);在化疗所引发的白细胞、血红蛋白和血小板降低等部分毒副反应发生率方面低于单纯NP方案化疗组(P<0.05)。结论:金龙胶囊联合NP化疗治疗晚期非小细胞肺癌不仅可以起到化疗增效的作用,而且能够明显提高患者生活质量,有效的改善临床症候,降低化疗引发的毒副反应,这一联合治疗方案可以在临床治疗中广泛推广。     

行胶囊内镜检查67 例患者临床结果分析

目的:评价胶囊内镜在小肠疾病中的诊断价值,总结胶囊内镜临床应用策略。方法:回顾性分析上海市第一人民医院胃肠镜室2009年7月-2011年4月67例行胶囊内镜检查患者的检查结果,结合其中32名患者双气囊小肠镜检查结果及手术病理,分析胶囊内镜在小肠疾病的检出率,诊断率和不良事件发生率,总结胶囊内镜检查时的注意事项。结果:1例胶囊内镜操作失败,66例受检者检出率80.3%,诊断率为66.7%,发现病变中血管病变为主要诊断,占62.1%,其次为肠道占位(息肉、肿瘤)为14.6%,克罗恩病占10.9%,所有患者均未出现严重不良事件。结论:胶囊内镜在小肠疾病检查中安全,无创,诊断率较高,临床胶囊内镜检查时建议充分肠道准备,实时监控及结合双气囊小肠镜检查。     

The role of encapsulated anaerobic bacteria in synergistic infections

Abstract: The effect of encapsulation on the virulence, survival, and protection of anaerobic bacteria from phagocytosis is reviewed. Support for the importance of encapsulated Gram-negative anaerobic rods ( Bacteroides sp., Prevotella sp. and Porphyromonas sp.), anaerobic and facultative Gram-positive cocci (AFGPC) was provided by their higher recovery rate in oropharyngeal infections, abscesses and blood, compared to their number in the normal flora. The pathogenicity of Bacteroides, Fusobacterium, Clostridium , and AFGPC was studied by inoculating them into mice and observing their ability to induce subcutaneous abscesses. Encapsulated Bacteroides, Fusobacteria , and AFGPC generally induced abscesses, whereas non-encapsulated organisms did not. However, many of the strains that had only a minimal number of encapsulated organisms (< 1%) survived in the abscesses, and they became heavily encapsulated when inoculated with other viable or non-viable encapsulated bacteria. Thereafter, these strains were able to induce abscesses when injected alone. Encapsulated Gram-negative anaerobic rods and AFGPC-induced bacteraemia and translocation, and increased the mortality of the infected animals more often than did the non-encapsulated form of the same strains. As determined by using selective antimicrobial therapy and quantitative cultures of abscesses induced in mice, possession of a capsule generally made Gram-negative anaerobic rods more important than their aerobic counterparts. Synergistic potentials were seen between encapsulated Gram-negative anaerobic rods and all tested aerobic bacteria and most AFGPC, and also between most AFGPC and Pseudomonas aeruginosa or Staphylococcus aureus . These studies demonstrated the importance of encapsulated anaerobes in mixed infections.     

消痰平喘胶囊体外抑菌效果研究

目的探讨消痰平喘胶囊对引起上呼吸道感染的致病菌抑菌效果。方法按照新药临床指导原则的要求,采用2倍稀释法测定消痰平喘胶囊对试验菌株的最小抑菌浓度(MIC)。结果消痰平喘胶囊对金黄色葡萄球菌、甲型溶血性链球菌、乙型溶血性链球菌、肺炎球菌和流感嗜血杆菌MIC50和MIC50分别为0．375～1．5mg／ml、0．75～3.0mg／ml。结论消痰平喘胶囊对引起呼吸道感染的常见致病菌具有较强的抑制作用。     

影响杏黄兜兰种子萌发的因素

通过在不同条件下杏黄兜兰 (Paphiopedilumarmeniacum)种子萌发的观察 ,对影响其萌发的诸因子报道如下 :1)果实的生长期与种子的萌发率有关。实验表明种子采自生长期为 6 0d的果实 ,发芽率为 3 5 % ,采自 12 0d的果实 ,发芽率为 4 0 % ,采自 180d的果实 ,发芽率为 18 3%。 2 )培养基也会影响到种子的萌发 ,种子在 1 5MS内培养 ,萌发率明显高于培养于MS ,RE和改良HyponexNo 1内的种子。 3)培养基 (1 5MS)掺入添加物也会影响到种子的萌发率 ,如掺入 10 %椰子水会促使种子的萌发率达到很高的水平 ,掺入马铃薯泥 (5 0g L)或胰化胨 (2g L) ,种子的萌发率会达到较高的水平 ,而掺入香蕉泥则会对种子的萌发率产生负面影响 ,掺入活性炭 (2g L)会促使种子萌发和幼苗发育。 4 )与固态培养基相比 ,种子在液体悬浮培养基内的萌发速度更快 ,幼苗更为整齐划一。     

The effects of Escherichia coli capsule, O-antigen, host neutrophils, and complement in a rat model of Gram-negative pneumonia

Gram-negative enteric bacilli are agents of life-threatening pneumonia. The role of the bacterial capsule and O-antigen moiety of lipopolysaccharide in the pathogenesis of Gram-negative pneumonia was assessed. In a rat model of pneumonia the LD(50) of a wild-type extraintestinal pathogenic Escherichia coli strain (CP9) was significantly less than its isogenic derivatives deficient in capsule (CP9.137), O-antigen (CP921) or both capsule and O-antigen (CP923) (P< or =0.003). Studies using complement depleted or neutropenic animals established that both neutrophils and complement are important for the pulmonary clearance of E. coli. Data from these studies also support that capsule and O-antigen serve, at least in part, to counter the complement and neutrophil components of the pulmonary host defense response. Lastly, the contribution of E. coli versus neutrophils in causing lung injury was examined. Findings suggest that E. coli virulence factors and/or non-neutrophil host factors are more important mediators of lung injury than neutrophils. These findings extend our understanding of Gram-negative pneumonia and have treatment implications.     

Role of capsule in Klebsiella pneumoniae virulence: lack of correlation between in vitro and in vivo studies

In vitro and in vivo models were used to investigate the role of capsule on the virulence of Klebsiella pneumoniae. We showed that capsule expression reduces dramatically the ability of the K. pneumoniae to bind to epithelial cells when compared to its non-capsulated variant. The presence/absence of capsule had no effect on the colonization of the gastrointestinal tract, while in the urinary tract we established that capsule is an important virulence factor. Our study demonstrates the caution needed when extrapolating from results of in vitro studies and emphasizes the necessity of in vivo models in studies of bacterial virulence.