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C. Korsi Dumenyo Asita Mukherjee Wesley Chun Arun K. Chatterjee 《European journal of plant pathology / European Foundation for Plant Pathology》1998,104(6):569-582
N-acyl homoserine lactones (AHLs) function as cell density (quorum) sensing signals and regulate diverse metabolic processes in several gram negative bacteria. We report that strains of Pseudomonas syringae pvs. syringae (Pss), tabaci and tomato as well as P. corrugata and P. savastanoi produce difussible AHLs that activate the lux operons of Vibrio fischeri or the tra::lacZ fusion of Agrobacterium tumefaciens. In Pss strain B3A, AHL production occurs in cell density dependent manner. Nucleotide sequence and genetic complementation data revealed the presence of ahlIPss, a luxI homolog within the Ahl+ DNA of Pss strain B3A. The
DNA expresses in AHL-deficient strains of P. fluorescens and E. carotovora subsp. carotovora (Ecc), and restores extracellular enzyme production and pathogenicity in the Ecc strain. The derivatives of Pss strains B3A and 301D carrying chromosomal ahlI::lacZ do not produce AHL, but like their wild type parents, produce extracellular protease and the phytotoxin syringomycin as well as elicit the hypersensitive reaction in tobacco leaves. While these strains also produce a basal level of -galactosidase activity, the expression of ahlI::lacZ is substantially stimulated in the presence of multiple copies of the
DNA or by the addition of cell-free spent cultures containing AHL. The activation of -galactosidase production occurs with spent cultures of some, but not all Pseudomonas strains which produce AHL as indicated by the Lux and tra::lacZ assays. Pss strains deficient in the global regulatory genes, gacA or lemA, produce very low levels of AHL. Since inactivation of ahlIPss eliminates AHL production and since Ahl+ Pseudomonas strains carry the homolog of ahlIPss, we conclude that ahlIPss specifies a key step in AHL biosynthesis and it has been conserved in many plant pathogenic pseudomonads. 相似文献
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许多植物病原细菌通过群体感应（quorum sensing,QS）系统调控相关毒性因子的表达,而群体感应淬灭（quorum quenching,QQ）是通过干扰QS系统,达到防治植物细菌性病害的重要策略之一。本研究利用原位培养法分离得到2000多株不同菌株形态的植物根围细菌,结合QS系统信号分子检测平板筛选到7株具有QQ活性的候选细菌,其中菌株37-1可完全降解信号分子。16S rDNA序列分析表明,菌株37-1属于Shinella sp.。全基因组序列分析发现菌株37-1中存在一个可能的QQ降解酶编码基因aiiS（autoinducer inactivation gene from Shinella sp.）。系统发育分析表明AiiS属于α/β水解酶家族蛋白。液相色谱-串联质谱分析进一步表明AiiS可水解N-乙酰高丝氨酸内酯（N-acylhomoserine lactone,AHL）类QS信号分子中的内酯健,生成酰基高丝氨酸,因此AiiS属于AHL内酯酶。将aiiS基因导入胡萝卜软腐果胶杆菌Pectobacterium carotovorum subsp.carotovorum Z3-3中,可显著降低该菌AHL信号分子和果胶酸盐裂解酶的产生及其在白菜、马铃薯和胡萝卜上的致病性。以上结果表明菌株37-1中AiiS蛋白是一种AHL内酯酶;病原细菌中异源表达aiiS基因可有效干扰相关病原细菌中QS系统的调控功能,表明AiiS蛋白具备开发为潜在新型生防制剂的价值。 相似文献
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为了解类植物乳杆菌L-XM1 plnBCD编码蛋白的生物学特性,并推测其功能,综合运用RPS-Blast、InterProscan和TMHMM Server等多种生物信息学软件预测分析plnBCD编码蛋白的理化性质、疏水性、磷酸化位点、保守性功能域及二级结构,并用Swiss-model同源建模。结果表明:plnB编码蛋白为疏水性蛋白,定位于细胞质膜上,有6个跨膜区、21个磷酸化位点和1个HATPase_c结构域,具有大多数组氨酸蛋白激酶的基本性质。其二级结构以α-螺旋和延伸链为主要构件,其空间结构与组氨酸蛋白激酶的结构特征一致。plnC及plnD编码蛋白均为亲水性蛋白,不具有跨膜区,定位于细胞质中,均具有1个REC和1个LytTR结构域。plnC及plnD编码蛋白与感应调节蛋白的空间结构具有较高的相似度。推测菌株L-XM1 plnBCD基因编码蛋白为群体感应调控系统组分。对plnBCD基因的生物信息学分析的研究可为发现新的群体感应系统和深入研究群体感应系统各组分的功能提供参考。 相似文献
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群体感应(quorum-sensing,QS)是一种微生物细胞间的通讯机制,微生物通过分泌信号分子来感知细胞(群体)密度,并在信号分子达到一定浓度时,通过调节特定基因的表达来调控群体内微生物众多生理生化过程的行为.研究发现群体感应广泛存在于微生物界,并在调控微生物间的共生或竞争中发挥了重要作用.反刍家畜瘤胃适宜的环境(如恒定的温度、pH及充足的养分)为众多微生物的生长提供了良好条件,同时,这些瘤胃微生物在对营养物质进行降解时存在着复杂的共生、竞争关系.目前,研究人员经研究证实反刍家畜瘤胃微生物同样具有群体感应,本文对反刍家畜瘤胃微生物群体感应的研究进展进行了综述,并对今后该领域的研究作出了展望. 相似文献
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本文利用群体感应信号报告菌Agrobacterium tumefaciens NTL4(pZLR4),在LB报告平板上对燕麦食酸菌西瓜亚种的19个菌株进行了初步检测,发现18个菌株有群体感应信号产生.用琼脂条法对菌株Pslb-94进一步检测,证实菌株Pslb-94存在群体感应系统.提取了该菌株信号物质,反相薄层层析(TLC)检测证明该菌株能产生群体感应信号分子. 相似文献
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Fernando Dures Nikoletta Szemerdi Decha Kumla Madalena Pinto Anake Kijjoa Gabriella Spengler Emília Sousa 《Marine drugs》2021,19(9)
Marine-derived fungi constitute an interesting source of bioactive compounds, several of which exhibit antibacterial activity. These acquire special importance, considering that antimicrobial resistance is becoming more widespread. The overexpression of efflux pumps, capable of expelling antimicrobials out of bacterial cells, is one of the most worrisome mechanisms. There has been an ongoing effort to find not only new antimicrobials, but also compounds that can block resistance mechanisms which can be used in combination with approved antimicrobial drugs. In this work, a library of nineteen marine natural products, isolated from marine-derived fungi of the genera Neosartorya and Aspergillus, was evaluated for their potential as bacterial efflux pump inhibitors as well as the antimicrobial-related mechanisms, such as inhibition of biofilm formation and quorum-sensing. Docking studies were performed to predict their efflux pump action. These compounds were also tested for their cytotoxicity in mouse fibroblast cell line NIH/3T3. The results obtained suggest that the marine-derived fungal metabolites are a promising source of compounds with potential to revert antimicrobial resistance and serve as an inspiration for the synthesis of new antimicrobial drugs. 相似文献
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Analysis of the relationship between luminescence and toxicity of <Emphasis Type="Italic">Vibrio carchariae</Emphasis> pathogenic to shrimp 总被引：1，自引：0，他引：1
Tatsuya?Nakayama Nakao?Nomura Masatoshi?MatsumuraEmail author 《Fisheries Science》2005,71(6):1236-1242
ABSTRACT: Aquaculture deterioration is caused by Vibrio harveyi , which is one of the main shrimp pathogens. Vibrio carchariae having the same phenotypic characteristics as V. harveyi was isolated from a shrimp farm and used in this study to investigate the relationship between luminescence and toxicity. Luminescence was verified by monitoring the expression of the LuxR gene. It was found that the relationship between the expression of LuxR and toxicity was the most significant factor related to luminescence. Results showed that LuxR expression was highest after 20 h of culture, which is comparable to the highest scintillation counter luminescence value (20 h). However, toxin levels in the culture broth were highest between 24 h-36 h of culture. Significant decrease in the toxicity level was observed after 36 h. It was also found that there was a decrease in toxicity level after 12 h of incubation at room temperature of the V. carchariae culture supernatant. The effect of the addition of cell-free culture supernatant on the luminescence of V. carchariae was also determined. Results showed that the addition of cell-free supernatant from 24 h-old culture was most effective in inducing and maintaining luminescence. 相似文献
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群体感应,也被称为"细胞间的交流",是细菌通过化学信号的传递进行彼此交流的一种方式。本文介绍了群体感应的机理和类型以及信号分子的检测方法,并结合实际情况,对其在水产养殖领域的应用前景进行了探讨,以期为群体感应在水产养殖中的应用提供理论依据。 相似文献