铜绿假单胞菌生物膜肺部感染大鼠血清IgG抗体及肺部IFN-γ水平的变化

目的 了解人工铜绿假单胞菌(PA)生物膜肺部感染对机体免疫功能的影响.方法 由支气管内直接注入PA(菌种为PAO579)藻酸盐微粒1×109CFU/mL),建立慢性PA生物膜肺部感染大鼠模型,以支气管内注入生理盐水作为对照,2周后评估血清PA特异性抗体IgG水平、肺部IFN-γ反应的变化及其与肺组织病理学的相关性.结果 PA感染2周后,PA感染组的血清抗PA IgG抗体水平显著升高(P＜0.01),并与其肺部大体观病理指数(LIMP)呈正相关(r=0.89,P＜0.05);而肺部IFN-γ水平明显降低(P＜0.01),其变化水平与LIMP呈负相关(r=-0.9,P＜0.05),镜下观肺病灶内大量多形核白细胞浸润.结论 PA生物膜肺部感染可能通过诱导Th2型免疫反应为主,从而引发以多形核白细胞浸润为主的Ⅲ型变态反应所导致的肺组织损害.     

镧对青枯假单胞菌生长及若干生化性状的影响

单一稀土氧化镧Ｌａ２Ｏ３对青枯假单胞菌的生长有明显抑制作用。当Ｌａ３＋质量浓度为５０,１００,１５０,２００,２５０,３００,３５０ｍｇ／Ｌ时,与对照相比,固体平板上病菌初生长时间延迟,７天后的菌落直径减小,生长量也减少。液体培养中的生物量也比对照显著下降。当Ｌａ３＋质量浓度大于３５０ｍｇ／Ｌ时,病菌停止生长。浓度为２００ｍｇ／Ｌ的Ｌａ３＋明显刺激该病菌的胞外蛋白酶、果胶酶及纤维素酶活性。     

北冰洋产淀粉酶海洋细菌的筛选与鉴定及其产酶条件的优化

[目的]筛选与鉴定北冰洋产淀粉酶海洋细菌,并对筛选出的细菌进行产酶条件优化.[方法]从156株北冰洋海洋细菌中筛选出淀粉酶高产菌株Arc B84A,并对其进行了菌株形态学鉴定、16S rRNA分子鉴定以及产酶条件优化.[结果]菌株Arc B84A属于交替假单胞菌属.菌株Arc B84A的最佳产酶条件为:培养基起始pH值为7.0～8.0;最佳碳源为0.5%葡萄糖;最佳氮源为1.0%蛋白胨;TritonX-100、Tween-20、Tween-80等表面活性剂可以提高菌株淀粉酶活性,其中1.0% Tween-80的效果最为明显.[结论]该研究为海洋细菌淀粉酶的生产与应用提供了理论依据.     

运营商与SP合作关系的系统动力学仿真研究

运营商与服务提供商(SP)的竞合关系一直是各方关注的重点问题,以移动增值业务产业链为研究对象,对SP和运营商的业务收入影响因素进行分析的同时,使用系统动力学进行仿真分析.通过对各影响因素调整,找到最优的合作模式,以实现整个产业链利润最大化.     

智慧高速管控系统的理论设计与探索

随着经济社会的快速发展以及机动车数量的迅猛增长,造成了安全管理、资源环保等瓶颈制约以及高速公路通行压力剧增等问题。伴随着信息化、智能化技术的快速发展,智慧高速公路建设成为顺时之举。鉴于此,结合宿迁公安规划建设的高速公路智慧管控系统的理论设计和实践成效,在高速公路交通安全主动管理,即侧重于交通安全防范性管控方面进行尝试和探索,提出一种智慧高速管控系统,其由数字化采集、网络化传输、智能化应用和规范化制度四大体系构成,可应用于三大应用领域中的八个应用场景。在新扬高速宿迁南段对提出的智慧管控系统进行验证,实验结果证明其取得了较好的应用效果。     

浅析质量管理体系中活动过程与系统之间的关系

本文通过对质量管理体系中活动、过程、系统的分别阐述,剖析了三者之间的内在关系,提出了简化管理,提高效益的工作思路。     

井下通风机的监控系统研究与设计

对风机的工作方式与流程进行了探讨,设计了监控系统的整体方案,分析研究了系统的控制结构与控制原理。对系统控制柜的硬件设备进行选型,设计分析了系统的主电路与风机信号监测的原理等。设计了系统软件主程序的工作流程图。监控系统具有较强的抗干扰性,对风机运行的关键信号进行了监测,为井下持续的通风提供了保障。     

轧钢线故障诊断及分析系统的研究与应用

本文介绍了山钢股份济南分公司宽厚板厂轧钢线故障诊断及分析系统的研究与应用,详细说明了轧钢数据的采集、分析及故障快速诊断系统,重点介绍了对轧钢线的故障诊断及分析方法,经过在宽厚板厂轧钢线的应用,取得了很好的效果。     

扒渣站系统的研究与改进

针对山西太钢不锈钢股份有限公司新投产的电炉、AOD炉前后扒渣站系统在生产过程中出现的常见问题进行了分析研究，并对可能出现的典型故障提出了解决办法。     

电子衡防作弊系统的研究与应用

对电子汽车衡称重常见的作弊手段、防作弊系统的功能进行了全面的阐述,介绍了防作弊系统软件和电子防盗报警仪在电子汽车衡和电子轨道衡上的应用.     

Active efflux and diffusion are involved in transport of Pseudomonas aeruginosa cell-to-cell signals

Many gram-negative bacteria communicate by N-acyl homoserine lactone signals called autoinducers (AIs). In Pseudomonas aeruginosa, cell-to-cell signaling controls expression of extracellular virulence factors, the type II secretion apparatus, a stationary-phase sigma factor (sigmas), and biofilm differentiation. The fact that a similar signal, N-(3-oxohexanoyl) homoserine lactone, freely diffuses through Vibrio fischeri and Escherichia coli cells has led to the assumption that all AIs are freely diffusible. In this work, transport of the two P. aeruginosa AIs, N-(3-oxododecanoyl) homoserine lactone (3OC12-HSL) (formerly called PAI-1) and N-butyryl homoserine lactone (C4-HSL) (formerly called PAI-2), was studied by using tritium-labeled signals. When [3H]C4-HSL was added to cell suspensions of P. aeruginosa, the cellular concentration reached a steady state in less than 30 s and was nearly equal to the external concentration, as expected for a freely diffusible compound. In contrast, [3H]3OC12-HSL required about 5 min to reach a steady state, and the cellular concentration was 3 times higher than the external level. Addition of inhibitors of the cytoplasmic membrane proton gradient, such as azide, led to a strong increase in cellular accumulation of [3H]3OC12-HSL, suggesting the involvement of active efflux. A defined mutant lacking the mexA-mexB-oprM-encoded active-efflux pump accumulated [3H]3OC12-HSL to levels similar to those in the azide-treated wild-type cells. Efflux experiments confirmed these observations. Our results show that in contrast to the case for C4-HSL, P. aeruginosa cells are not freely permeable to 3OC12-HSL. Instead, the mexA-mexB-oprM-encoded efflux pump is involved in active efflux of 3OC12-HSL. Apparently the length and/or degree of substitution of the N-acyl side chain determines whether an AI is freely diffusible or is subject to active efflux by P. aeruginosa.     

Resistance of Pseudomonas aeruginosa PAO1 phage F116 to sodium hypochlorite

The development of viral resistance to sodium hypochlorite was investigated using the Pseudomonas aeruginosa bacteriophage F116 as a model system. This phage was chosen because of its structural characteristics and former investigations conducted in this laboratory. F116 was shown to be sensitive to a sodium hypochlorite concentration of 0.0075 gl-1 (available chlorine) which produced a 5 log10 reduction in titre in a suspension test. Survival bacteriophages challenged with this sodium hypochlorite concentration were isolated, propagated and challenged again with the same and higher concentrations of the biocide. It was observed that progeny virions were becoming increasingly resistant to sodium hypochlorite challenges up to a concentration of 0.0175 gl-1 of available chlorine. It was also noticed that 1-2 log10 of F116 virions from resistant phage lysates remained sensitive to the biocide. An electron microscopical investigation of F116 resistant lysates showed that the phage resistance to sodium hypochlorite was not caused by F116 particles aggregation. Furthermore, no morphological difference between the sensitive and resistant F116 particles to sodium hypochlorite was identified.     

Relationship between glycocalyx and povidone-iodine resistance in Pseudomonas aeruginosa (ATCC 27853) biofilms

Samples of duck eggs were collected from 65 farms distributed in 6 counties in Taiwan to analyze the contents of Pb, Cd, Hg, and Cu in albumen and yolk. Lead, Cd, and Cu determinations were performed by microwave digestion together with atomic absorption spectrophotometry, whereas Hg was analyzed by sulfuric acid-nitric acid digestion and cold vapor atomic absorption spectrophotometry. Expressed on a wet weight basis, the average concentrations (ranges) of the four metals were as follows: Pb, 13.6 ng/g (.8 to 27.5) in albumen and 84.7 ng/g (44.8 to 224.7) in yolk; Cd, 1.8 ng/g (< .5 to 4.4) in albumen and 3.8 ng/g (< 1.0 to 5.7) in yolk; Hg, 17.8 ng/g (2.5 to 47.5) in albumen and 9.7 ng/g (1.2 to 20) in yolk; Cu, .83 micrograms/g (.56 to 1.08) in albumen and 1.36 micrograms/g (.95 to 1.95) in yolk. Comparison of the calculated daily intakes of Pb, Cd, and Hg from eggs with the World Health Organization-Food Agriculture Organization provisional tolerated daily intakes suggest that duck eggs are safe with respect to the contents of the three metals. Eggs are poor sources of Cu, supplying less than 2% of the Recommended Dietary Allowance.     

Penicillin-resistant mechanisms in Pseudomonas aeruginosa: binding of penicillin to Pseudomonas aeruginosa KM 338

A comparison of the binding of radioactive penicillin G to whole cells and the membrane fraction derived from Pseudomonas aeruginosa KM 338 was made. This organism has intrinsic resistance to penicillin. The binding to the membrane fraction which catalyzed peptidoglycan synthesis followed saturation type kinetics and saturation was achieved at approximately 2 nmol of penicillin G per ml, whereas binding to the whole cells was entirely of the nonsaturation type. The binding of carbenicillin to the membrane fraction was determined by competition between radioactive penicillin G and unlabeled carbenicillin for the binding sites. It was bound at the same sites in almost the same manner. When whole cells were pretreated with high concentration of unlabeled penicillin G or carbenicillin, the subsequent binding of radioactive penicillin G to the membrane fraction from carbenicillin-treated cells was entirely nonspecific, but with penicillin G-pretreated cells it was still specific. There was apparently specific binding of radioactive penicillin G to ethylenediaminetetraacetate-treated cells. P. aeruginosa KM 338 had an extremely low activity of beta-lactamase compared with other enzyme-producing organisms. This enzyme from P. aeruginosa KM 338 was of the cephalosporinase type. These data indicate that penicillin resistance of P. aeruginosa KM 338 may be a consequence of the development of a permeability barrier which prevents the antibiotic from reaching its sites of action in the cytoplasmic membrane.     

Heterogeneity of the lipopolysaccharide from Pseudomonas aeruginosa

Lipopolysaccharide isolated from pseudomonas aeruginosa PAC1 and its phage-resistant mutant was degraded by mild acid hydrolysis into lipid A and three major polysaccharide-containing fractions which were separated on Sephadex G-75. The low-molecular-weight fraction contained glucose, rhamnose, heptose, galactosamine, alanine and phosphate. The higher-molecular-weight fractions consisted mainly of glucose, rhamnose and glucosamine together with amino compounds. Alkaline degradation of the lipopolysaccharide produced at least four different species each of which contained a low-molecular-weight polysaccharide similar if not identical to that produced by acid hydrolysis. Under certain growth conditions an abnormal lipopolysaccharide was produced which was defective in the low-molecular-weight polysaccharide and contained mainly high-molecular-weight material. Strains of different serotype yielded lipopolysaccharides which also exhibited heterogeneity but contained a low-molecular-weight polysaccharide similar to that obtained from strain PAC1 and PAC1R. It is suggested that each strain of P. aeruginosa may produce several lipopolysaccharides each containing a polysaccharide common to all. The relative proportions of the various lipopolysaccharides may be changed by growth conditions.     

Lung function in bronchiectasis: the influence of Pseudomonas aeruginosa

Sputum isolation of Pseudomonas aeruginosa (PA) is associated with extensive disease in bronchiectasis. It is not known, however, whether infection with P. aeruginosa is the result or the cause of severe disease. We compared spirometry in patients with bronchiectasis before and after infection with P. aeruginosa, with that of patients infected by other organisms. All patients (n=12) with chronic colonization by P. aeruginosa (PA group) were studied. These were compared with other patients with bronchiectasis with no isolations of P. aeruginosa (n=37, non-PA group). In the PA group, forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were lower than in the non-PA group. The PA group, however, also had lower values at the time of initial colonization with P. aeruginosa than the current values for the non-PA group. Change in FEV1 and FVC over time was faster in the PA group than in the non-PA group. Reduction of FEV1 and FVC over time in the PA group prior to P. aeruginosa colonization was intermediate, not being statistically different from either value above. Our results confirm the association of chronic P. aeruginosa colonization with poor lung function, but conclude that patients with bronchiectasis who become colonized by P. aeruginosa have poorer lung function when first colonized than those colonized by other organisms. Decline in lung function is faster in those chronically colonized by P. aeruginosa than in those colonized by other organisms. It is not clear whether chronic P. aeruginosa colonization causes an accelerated decline in lung function or whether it is simply a marker of those whose lung function is already declining rapidly.     

Epidemiology of community-acquired Pseudomonas aeruginosa infections in children

The epidemiology of community-acquired Pseudomonas aeruginosa infections in children during a one-year period (January through December 1993) was evaluated. A total of 6,859 clinical samples, each one representing a separate individual with suspected infection, were cultured. Pseudomonas aeruginosa was isolated from 218 children with various infections occurring in the following order of frequency: chronic suppurative otitis media, 76.3%; appendicitis/peritonitis, 10.3%; osteomyelitis, 8.9%; skin or soft tissue infection, 6.3%; acute conjunctivitis, 3.0%; and urinary tract infection, 0.1%. A variety of O serogroups were identified: O1 (15.2%), O6 (14.7%), O11 (12.4%), O10 (11.5%), O3 (10.6%), O5 (5.1%), and O9 (4.6%). Other serogroups and nontypable strains were recovered at a frequency of 11.2% and 14.7%, respectively. Nontypable strains predominated in chronic otitis media (18.9%), while serogroups O1 (18.3%), O6 (17.5%), and O11 (17.5%) were recovered most frequently among the typable isolates. Susceptibility of Pseudomonas aeruginosa to antipseudomonadal agents was extremely high. The rate of susceptibility to ceftazidime was 99.6%, to azlocillin 98.6%, to piperacillin 98.2%, to aztreonam 97.3%, to gentamicin and netilmicin 97.7%, and to ciprofloxacin 99.1%. All isolates were susceptible to tobramycin, imipenem, and amikacin. The results might suggest that community-acquired Pseudomonas aeruginosa infections in children can be treated successfully with any antipseudomonadal antibiotic.