ABSTRACT
Multidrug-resistant bacteria are a growing issue worldwide. This study developed a convenient and effective method to downregulate the expression of a specific gene to produce a novel antimicrobial tool using a small (140 nucleotide) RNA with a 24-nucleotide antisense (as) region from an arabinose-inducible expression phagemid vector in Escherichia coli. Knockdown effects of rpoS encoding RNA polymerase sigma factor were observed using this inducible artificial asRNA approach. asRNAs targeting several essential E. coli genes produced significant growth defects, especially when targeted to acpP and ribosomal protein coding genes rplN, rplL, and rpsM. Growth inhibited phenotypes were facilitated in hfq- conditions. Phage lysates were prepared from cells harboring phagemids as a lethal-agent delivery tool. Targeting the rpsM gene by phagemid-derived M13 phage infection of E. coli containing a carbapenem-producing F-plasmid and multidrug-resistant Klebsiella pneumoniae containing an F-plasmid resulted in the death of over 99.99% of infected bacteria. This study provides a possible strategy for treating bacterial infection and can be applied to any F-pilus producing bacterial species.
Subject(s)
Anti-Bacterial Agents/administration & dosage , Bacteriophage M13/genetics , Escherichia coli/drug effects , F Factor/genetics , Klebsiella pneumoniae/drug effects , RNA, Antisense/administration & dosage , Anti-Bacterial Agents/metabolism , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Drug Delivery Systems , Drug Resistance, Multiple, Bacterial/drug effects , Escherichia coli/genetics , Escherichia coli/growth & development , Escherichia coli Infections/drug therapy , Escherichia coli Infections/microbiology , Gene Expression Regulation, Bacterial/drug effects , Gene Knockdown Techniques , Genetic Engineering/methods , Humans , Klebsiella Infections/drug therapy , Klebsiella Infections/microbiology , Klebsiella pneumoniae/genetics , Klebsiella pneumoniae/growth & development , Pili, Sex/genetics , RNA, Antisense/genetics , RNA, Antisense/pharmacology , Ribosomal Proteins/genetics , Sigma Factor/geneticsABSTRACT
Pungent substances, such as capsaicin and gingerol, activate the transient receptor potential (TRP)-V1 channel and affect the feeding behaviors of animals. To gain insight into how living organisms have acquired a sense for pungent substances, we explored the response to TRP agonists in a protist, Chlamydomonas reinhardtii When capsaicin or gingerol was applied to wild-type cells, they became immotile, with flagella detaching from the cell body. The degree of deflagellation was nearly halved in a mutant defective in the TRP channel ADF1. Deflagellation in the adf1 mutant was inhibited further by Ruthenium Red, indicating ADF1 and another TRP channel are involved in the deflagellation response. The response to capsaicin and gingerol was not inhibited by TRPV1-specific blockers such as 4-(3-Chloro-2-pyridinyl)-N-[4-(1,1-dimethylethyl)phenyl]-1-piperazinecarboxamide (BCTC) and capsazepine. When capsaicin or gingerol was applied to wild-type cells in the presence of Ruthenium Red, a large proportion lost motility while flagella remained attached, suggesting that flagella stop contributing to motility, at least in part, through a TRP-channel-independent pathway. These results indicate that pungent compounds such as capsaicin and gingerol induce loss of flagellar motility and flagellar detachment in C.reinhardtii cells.
