Piericidin A1, 3’-rhamnopiericidin A1, and a novel compound piericidin E, a new quorum-sensing (QS) inhibitor against Chromobacterium violaceum CV026, were isolated from the culture broth of Streptomyces sp. QS is we...Piericidin A1, 3’-rhamnopiericidin A1, and a novel compound piericidin E, a new quorum-sensing (QS) inhibitor against Chromobacterium violaceum CV026, were isolated from the culture broth of Streptomyces sp. QS is well known as a microbial signaling system and controls certain types of gene expression resulting in bioluminescence, biofilm formation, swarming motility, antibiotic biosynthesis, and virulence factor production. C. violaceum CV026 is commonly used to determine qualitative and quantitative QS activity. The structures of piericidin derivatives were characterized, and their QS activities were determined.展开更多
Bacterial cells rely on signaling molecules to communicate with others from the same species and induce certain genes in a process known as quorum sensing (QS). A common molecule is N-acyl homoserine lactone (AHL) whi...Bacterial cells rely on signaling molecules to communicate with others from the same species and induce certain genes in a process known as quorum sensing (QS). A common molecule is N-acyl homoserine lactone (AHL) which is responsible for the expression of virulence and other factors that allow the organisms to compete in a given environment. On the other hand, other bacteria produce certain enzymes such as AHL-lactonase that break down AHL molecules and prevent gene expression of these factors. The aim of this work was to examine the level of degradation of AHL molecules by AHL-lactonase in 62 Bacillus thuringiensis (Bt) strains isolated from Middle Tennessee, Mississippi, and Alabama. N-hexanoyl-homoserine lactone (C<sub>6</sub>-HSL) and N-3-oxo-hexanoyl homoserine lactone (3-oxo-C<sub>6</sub>-HSL), which cause Chromobacterium violaceum (CV026) to produce a purple pigment were tested at different concentrations to view the Bt lactonase activity. In addition, PCR was used to test for the presence of the lactonase gene. The results showed that among the 62 Bt strains, there were 58 that possessed the AHL-lactonase (aiiA) gene and 48 strains were able to degrade C<sub>6</sub>-HSL. At high concentrations of AHL, only 13 strains were able to completely degrade C6-HSL. In addition, degradation of 3-oxo-C<sub>6</sub>-HSL was weak compared to C<sub>6</sub>-HSL. The results also revealed that AHL lactonase was thermostable, and it was concluded that the level of degradation varies in Bt strains. Only 13 of the strains studied have potent inhibitory activity against C<sub>6</sub>-HSL, which may be good to be used in field applications to control agricultural pest.展开更多
正红树根泥来源的沙门柏干酪青霉(Penicilliumcamemberti)OUCMDZ-1492在寡营养条件下能够产生一类不同于富营养条件下的代谢产物,具有细菌群体感应抑制活性.采用活性跟踪的分离方法并对其中的外消旋体进行手性拆分,得到了5个α-吡喃酮...正红树根泥来源的沙门柏干酪青霉(Penicilliumcamemberti)OUCMDZ-1492在寡营养条件下能够产生一类不同于富营养条件下的代谢产物,具有细菌群体感应抑制活性.采用活性跟踪的分离方法并对其中的外消旋体进行手性拆分,得到了5个α-吡喃酮类化合物;通过波谱分析、电子圆二色谱(ECD)的测量与化学模拟计算,其结构分别被鉴定为:(R,E)-6-甲基-5-(3-羟基-1-丁烯基)-4-甲氧基-2-吡喃酮(1,命名为pyrenocine P)、pyrenocine A (2)、(R)-pyrenocine B (3)、(R)-(―)-pyrenocine E (4)和(S)-(+)-pyrenocine E (5),其中化合物1为新化合物、化合物3～5的绝对构型为首次确定.化合物2和3对紫色杆菌(Chromobacterium violaceum) CV026显示出较强的群体感应抑制活性,最小抑制浓度MIC分别为0.16和1.0 mg·mL-1 [阳性药(Z)-4-溴-5-溴亚甲基-2-呋喃酮(C-30)的MIC为0.08 mg·mL-1].展开更多
目的:从海洋真菌中筛选得到新型群体感应抑制剂,并对其进行活性评价。方法:首先利用紫色杆菌CV026指示菌株对真菌发酵粗提物进行活性筛选。其次通过18S r DNA序列比对进行菌种鉴定,同时采用硅胶柱色谱、凝胶柱色谱和高效液相色谱等技术...目的:从海洋真菌中筛选得到新型群体感应抑制剂,并对其进行活性评价。方法:首先利用紫色杆菌CV026指示菌株对真菌发酵粗提物进行活性筛选。其次通过18S r DNA序列比对进行菌种鉴定,同时采用硅胶柱色谱、凝胶柱色谱和高效液相色谱等技术并结合活性追踪检测分离纯化的活性化合物,再通过核磁质谱分析确定其结构。最后利用定量测定方法检测其在亚抑菌浓度下对紫色杆菌紫色菌素产量影响以及RT-PCR检测与QS调控相关基因的m RNA表达的影响。结果:从海藻共生菌中筛选到一株具有紫色杆菌群体感应抑制活性的海洋真菌Penicillium sp.QF046,其次级代谢产物中纯化到的活性化合物根据结构鉴定为一种星形曲霉毒素(asteltoxin)。该化合物对于紫色杆菌群体感应抑制浓度低于阳性对照化合物呋喃酮C30,同时抑制了群体感应相关基因m RNA水平的表达。结论:从海洋真菌Penicillium sp.QF046代谢产物中发现了一种抑制紫色杆菌群体感应的星形曲霉毒素,为进一步通过结构改造研发新型抗菌药物提供良好的前体化合物。展开更多
文摘Piericidin A1, 3’-rhamnopiericidin A1, and a novel compound piericidin E, a new quorum-sensing (QS) inhibitor against Chromobacterium violaceum CV026, were isolated from the culture broth of Streptomyces sp. QS is well known as a microbial signaling system and controls certain types of gene expression resulting in bioluminescence, biofilm formation, swarming motility, antibiotic biosynthesis, and virulence factor production. C. violaceum CV026 is commonly used to determine qualitative and quantitative QS activity. The structures of piericidin derivatives were characterized, and their QS activities were determined.
文摘Bacterial cells rely on signaling molecules to communicate with others from the same species and induce certain genes in a process known as quorum sensing (QS). A common molecule is N-acyl homoserine lactone (AHL) which is responsible for the expression of virulence and other factors that allow the organisms to compete in a given environment. On the other hand, other bacteria produce certain enzymes such as AHL-lactonase that break down AHL molecules and prevent gene expression of these factors. The aim of this work was to examine the level of degradation of AHL molecules by AHL-lactonase in 62 Bacillus thuringiensis (Bt) strains isolated from Middle Tennessee, Mississippi, and Alabama. N-hexanoyl-homoserine lactone (C<sub>6</sub>-HSL) and N-3-oxo-hexanoyl homoserine lactone (3-oxo-C<sub>6</sub>-HSL), which cause Chromobacterium violaceum (CV026) to produce a purple pigment were tested at different concentrations to view the Bt lactonase activity. In addition, PCR was used to test for the presence of the lactonase gene. The results showed that among the 62 Bt strains, there were 58 that possessed the AHL-lactonase (aiiA) gene and 48 strains were able to degrade C<sub>6</sub>-HSL. At high concentrations of AHL, only 13 strains were able to completely degrade C6-HSL. In addition, degradation of 3-oxo-C<sub>6</sub>-HSL was weak compared to C<sub>6</sub>-HSL. The results also revealed that AHL lactonase was thermostable, and it was concluded that the level of degradation varies in Bt strains. Only 13 of the strains studied have potent inhibitory activity against C<sub>6</sub>-HSL, which may be good to be used in field applications to control agricultural pest.
文摘正红树根泥来源的沙门柏干酪青霉(Penicilliumcamemberti)OUCMDZ-1492在寡营养条件下能够产生一类不同于富营养条件下的代谢产物,具有细菌群体感应抑制活性.采用活性跟踪的分离方法并对其中的外消旋体进行手性拆分,得到了5个α-吡喃酮类化合物;通过波谱分析、电子圆二色谱(ECD)的测量与化学模拟计算,其结构分别被鉴定为:(R,E)-6-甲基-5-(3-羟基-1-丁烯基)-4-甲氧基-2-吡喃酮(1,命名为pyrenocine P)、pyrenocine A (2)、(R)-pyrenocine B (3)、(R)-(―)-pyrenocine E (4)和(S)-(+)-pyrenocine E (5),其中化合物1为新化合物、化合物3～5的绝对构型为首次确定.化合物2和3对紫色杆菌(Chromobacterium violaceum) CV026显示出较强的群体感应抑制活性,最小抑制浓度MIC分别为0.16和1.0 mg·mL-1 [阳性药(Z)-4-溴-5-溴亚甲基-2-呋喃酮(C-30)的MIC为0.08 mg·mL-1].
