• 제목/요약/키워드: Quorum sensing

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AHL inhibition of Beckerelide and Fimbrolide

  • Kim, Yeon-Hee;Lee, Jae-Gun;Park, Sung-Hoon;Kim, Jung-Sun
    • 대한약학회:학술대회논문집
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    • 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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    • pp.174.2-174.2
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    • 2003
  • Quorum sensing, a gene expression in response to population density, is regulated by chemical signals, most of which are acylated homoserine lactones (AHLs). The AHL derivatives have been reported to regulate bioluminescence, virulence factors and / or swarming motility in bacteria. It is hypothesized that higher organisms may have evolved specific means to interfere with bacterial communication as exemplified in the AHL-antagonistic activity of halogenated furanones isolated from the Australian macroalga Delisea pulchra. (omitted)

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Diversity and Polymorphism in AHL-Lactonase Gene (aiiA) of Bacillus

  • Huma, Nusrat;Shankar, Pratap;Kushwah, Jyoti;Bhushan, Ashish;Joshi, Jayadev;Mukherjee, Tanmoy;Raju, Sajan C.;Purohit, Hemant J.;Kalia, Vipin Chandra
    • Journal of Microbiology and Biotechnology
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    • 제21권10호
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    • pp.1001-1011
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    • 2011
  • To explore bacterial diversity for elucidating genetic variability in acylhomoserine lactone (AHL) lactonase structure, we screened 800 bacterial strains. It revealed the presence of a quorum quenching (QQ) AHL-lactonase gene (aiiA) in 42 strains. These 42 strains were identified using rrs (16S rDNA) sequencing as Bacillus strains, predominantly B. cereus. An in silico restriction endonuclease (RE) digestion of 22 AHL lactonase gene (aiiA) sequences (from NCBI database) belonging to 9 different genera, along with 42 aiiA gene sequences from different Bacillus spp. (isolated here) with 14 type II REs, revealed distinct patterns of fragments (nucleotide length and order) with four REs; AluI, DpnII, RsaI, and Tru9I. Our study reflects on the biodiversity of aiiA among Bacillus species. Bacillus sp. strain MBG11 with polymorphism (115Alanine > Valine) may confer increased stability to AHL lactonase, and can be a potential candidate for heterologous expression and mass production. Microbes with ability to produce AHL-lactonases degrade quorum sensing signals such as AHL by opening of the lactone ring. The naturally occurring diversity of QQ molecules provides opportunities to use them for preventing bacterial infections, spoilage of food, and bioremediation.

luxS and smcR Quorum-Sensing System of Vibrio vulnificus as an Important Factor for In Vivo Survival

  • SHIN NA-RI;BAEK CHANG-HO;LEE DEOG-YONG;CHO YOUNG-WOOK;PARK DAE-KYUN;LEE KO-EUN;KIM KUN-SOO;YOO HAN-SANG
    • Journal of Microbiology and Biotechnology
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    • 제15권6호
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    • pp.1197-1206
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    • 2005
  • Vibrio vulnificus is an opportunistic pathogen that causes a septicemia and expresses numerous virulence factors, in which luxS and smcR are genes encoding for components responsible for quorum-sensing regulation. In the present study, null mutants were constructed with lesions in each or both of these two genes from the V. vulnificus Vv$\Delta$Z strain, which is a lacZ$^{-}$ and chloramphenicol/streptomycin-resistant derivative of the wild-type ATCC29307 strain, and their phenotypes related to virulence were compared with those of the parental cells. $LD_{50}$ and histopathological findings of luxS-, smcR-, or luxS- smcR- deficient mutant were not different from those of the parent strain, a lacZ-deficient streptomycin-resistant strain in mice. However, time of death in mice was delayed, and numbers of bacteria survived in bloodstream after intraperitoneal injection in mice were decreased by mutation, especially luxS and smcR double mutant (VvSR$\Delta$ZSR). These phenomena were supported by increased serum sensitivity and delayed bacterial proliferation in both murine blood and iron-restricted medium. These results suggest that the luxS and luxR homologous genes in V. vulnificus could playa role in bacterial survival in host by enhancing proliferation and adjusting to changed environment.