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AhmadAli Pourbabaee Amaneh Soleymani Ehssan Torabi Hassan Alizadeh 《Soil & Sediment Contamination》2018,27(8):756-772
ABSTRACTThe dissipation and detoxification of nicosulfuron (NS) by Pseudomonas aeruginosa B9 isolated from a cornfield soil was investigated. The fastest decline of NS occurred at 40 µg ml?1 in liquid media with 0.25% glucose plus 0.05% yeast extract (DT50 = 4 days) with a notable pH reduction (pH ? 5). Bioassay tests showed considerable phytotoxicity of NS for Cress (Lepidium sativum L.) with 50% shoot growth inhibition (SGI) at 40 µg ml?1. The dissipation of NS (40 µg ml?1) by the B9 isolate reduced the SGI significantly (SGI: up to 45 ± 3%) compared to the non-inoculated media (SGI: up to 58 ± 4%). In soils with the B9 isolate, NS dissipation, especially at 0.3 µg g?1, was faster with a more significant SGI reduction (k = 0.08 ± 0.00 day?1; SGI = 2 ± 1%) compared to non-inoculated samples (k = 0.03 ± 0.00 day?1; SGI = 8 ± 1%). NS initially inhibited soil respiration, microbial biomass carbon, and dehydrogenase activity. The effect was however transient, and these parameters recovered within 10 days, especially in the presence of the isolate. Overall, this study proves Pseudomonas aeruginosa B9 as a suitable candidate for bioremediation of NS in contaminated sites. 相似文献
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Kurosaka Y Ishida Y Yamamura E Takase H Otani T Kumon H 《Microbiology and immunology》2001,45(1):9-15
This study established a rat model of foreign body-associated urinary tract infection. A spiral polyethylene tube (PT) was placed transurethrally into the bladder without surgical manipulation, followed by transurethral inoculation with Pseudomonas aeruginosa. The persistence of P. aeruginosa in the kidneys and bladder was significantly enhanced by placement of the PT, whereas the bacteria were eliminated rapidly from the urinary tract in the animals without the PT. Scanning electron microscopy revealed a thick biofilm on the surface of the PT from the early stage of infection. Histopathologically, acute pyelonephritis was followed by chronic renal inflammation as well as continuous and sporadic polymorphonuclear leukocyte accumulation and hemorrhage in the pelvis and adjacent tissues, suggesting continuous ascending introduction of the bacteria from the biofilm adhering to the PT. We believe our model simulates the pathophysiology of foreign body-associated urinary tract infection characterized by biofilm formation on the surface of a foreign body. 相似文献
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Molecular mechanisms of bacteria induced apoptosis 总被引:7,自引:0,他引:7
Grassmé H Jendrossek V Gulbins E 《Apoptosis : an international journal on programmed cell death》2001,6(6):441-445
Interaction of mammalian cells with pathogenic bacteria results in a whole variety of responses in the infected cells including internalization or phagocytosis of the bacterium, release of cytokines, secretion of defensins or production of oxygen radicals. However, recent studies pointed out that many bacteria are able to trigger apoptosis in the host cell. The induction of apoptosis upon infection results from a complex interaction of bacterial proteins with cellular proteins finally mediating apoptosis. Thus, bacteria are able to activate several pro-apoptotic proteins, e.g. caspases, to inactivate anti-apoptotic proteins, e.g. NFB or MAP-kinases, or to upregulate endogenous receptor/ligand systems, that induce apoptosis, on the surface of the infected cell. Host cell apoptosis very often serves the bacteria to attack the host and to gain access to the tissue. However, in some infections, apoptosis of mammalian cells significantly contributes to the host defense against the bacteria further indicating the role of apoptosis in host-pathogen interactions. 相似文献
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High-level fluoroquinolone resistance in Pseudomonas aeruginosa due to interplay of the MexAB-OprM efflux pump and the DNA gyrase mutation 总被引:4,自引:0,他引:4
Fluoroquinolone resistance in Pseudomonas aeruginosa is mainly attributable to the constitutive expression of the xenobiotic efflux pump and mutation in DNA gyrase or topoisomerase IV. We constructed cells with a double-mutation in gyrA and mexR encoding DNA gyrase and repressor for the mexAB-oprM operon, respectively. The mutant showed 1,024 times higher fluoroquinolone resistance than cells lacking the MexAB-OprM. Cells with a single mutation in gyrA and producing a wild-type level of the MexAB-OprM efflux pump showed 128 times higher fluoroquinolone resistance than cells lacking the MexAB-OprM. In contrast, a single mutation in gyrA or mexR caused only 4 and 64 times higher resistance, respectively. These findings manifested the interplay between the MexAB-OprM efflux pump and the target mutation in fluoroquinolone resistance. 相似文献
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白细胞介素2-绿脓杆菌外毒素融合基因的克隆及高效表达 总被引:2,自引:0,他引:2
利用聚合酶链式反应和寡核苷酸介导的定向诱变技术构建了白细胞介素2-绿脓杆菌外毒素IL2-PE40、IL2-PE40KDEL、IL2-PE66~(4Glu)和IL2-PE66~(4Glu)KDEL融合基因的原核表达重组质粒,并实现了高效表达,表达产物占菌体总可溶蛋白的20%~30%。此外,由于这一表达质粒在IL-2cDNA与PE基因连接处引入了唯一的SmaⅠ位点,其5'、3'端分别含有唯一的EcoRⅠ、PstⅠ位点,因此可方便地用其它基因替换IL-2或PE基因而获得相应融合蛋白的表达质粒。 相似文献
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为了筛选出能与铜绿假单胞菌PAO1 motA基因的mRNA结合紧密的反义寡核苷酸序列,采用全基因寻靶技术(full length gene targeting,FLGT),运用计算机软件(Mfold和RNA Structure4.6)模拟铜绿假单胞菌PAO1 motA基因mRNA的二级结构,根据最小自由能原理设计出8条寡核苷酸探针序列;PCR扩增出全长motA基因,克隆motA基因并进行体外转录,同时用地高辛标记mRNA,以斑点杂交方法筛选出与motA基因mRNA结合紧密、杂交信号较强的寡核苷酸序列。斑点杂交结果显示8条寡核苷酸中的4条有较强的杂交信号,从而成功筛选到了能与motA mRNA牢固结合的反义序列,为进一步研究以motA基因为靶的反义技术抑制生物膜形成打下基础。 相似文献