Regulation of Class A β-Lactamase CzoA by CzoR and IscR in Comamonas testosteroni S44

نویسندگان

  • Weiping Zhuang
  • Hongliang Liu
  • Jingxin Li
  • Lu Chen
  • Gejiao Wang
چکیده

A genomic analysis of Comamonas testosteroni S44 revealed a gene that encodes a LysR family transcriptional regulator (here named czoR, czo for cefazolin) located upstream of a putative class A β-lactamase encoding gene (here named czoA). A putative DNA-binding motif of the Fe-S cluster assembly regulator IscR was identified in the czoR-czoA intergenic region. Real-time RT-PCR and lacZ fusion expression assays indicated that transcription of czoA and czoR were induced by multiple β-lactams. CzoA expressed in Escherichia coli was shown to contribute to susceptibility to a wide range of β-lactams judged from minimum inhibitory concentrations. In vitro enzymatic assays showed that CzoA hydrolyzed seven β-lactams, including benzylpenicillin, ampicillin, cefalexin, cefazolin, cefuroxime, ceftriaxone, and cefepime. Deletion of either iscR or czoR increased susceptibility to cefalexin and cefazolin, while complemented strains restored their wild-type susceptibility levels. Electrophoretic mobility shift assays (EMSA) demonstrated that CzoR and IscR bind to different sites of the czoR-czoA intergenic region. Precise CzoR- and IscR-binding sites were confirmed via DNase I footprinting or short fragment EMSA. When cefalexin or cefazolin was added to cultures, czoR deletion completely inhibited czoA expression but did not affect iscR transcription, while iscR deletion decreased the expressions of both czoR and czoA. These results reveal that CzoR positively affects the expression of czoA with its own expression upregulated by IscR.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Global Regulator IscR Positively Contributes to Antimonite Resistance and Oxidation in Comamonas testosteroni S44

Antimonial compounds can be found as a toxic contaminant in the environment. Knowledge on mechanisms of microbial Sb oxidation and its role in microbial tolerance are limited. Previously, we found that Comamonas testosteroni S44 was resistant to multiple heavy metals and was able to oxidize the toxic antimonite [Sb(III)] to the much less toxic antimonate [Sb(V)]. In this study, transposon mutag...

متن کامل

Genome analysis and characterization of zinc efflux systems of a highly zinc-resistant bacterium, Comamonas testosteroni S44.

A novel and multiple metal(loid)-resistant strain Comamonas testosteroni S44 with a high Zn(2+) resistance level (10 mM) was isolated. To understand the molecular basis for the high zinc resistance, whole genome sequencing was performed and revealed a large number of genes encoding putative metal(loid) resistance proteins, mobile genetic elements (MGEs) and horizontal gene transfer (HGT) events...

متن کامل

Comamonas testosteroni: Is It Still a Rare Human Pathogen?

Comamonas testosteroni (formally Pseudomonas testosteroni) is common environmental bacterium that is not part of the human microbiome. Since its identification as a human pathogen in 1987, numerous reports have drizzled in, implicating this organism for various infections. Although these organisms are of low virulence, some of their obscurity perhaps is due to the incapability of clinical labor...

متن کامل

Draft Genome Sequence of Comamonas testosteroni R2, Consisting of Aromatic Compound Degradation Genes for Phenol Hydroxylase

Comamonas testosteroni strain R2 was isolated from a continuous culture enriched by a low concentration of phenol-oxygenating activities with low Ks values (below 1 μM). The draft genome sequence of C. testosteroni strain R2 reported here may contribute to determining the phenol degradation gene cluster.

متن کامل

Draft Genome Sequence of the Polychlorinated Biphenyl-Degrading Bacterium Comamonas testosteroni KF712 (NBRC 110673)

We present a 5.89-Mb draft genome sequence of Comamonas testosteroni KF712 (NBRC 110673), a polychlorinated biphenyl degrader. The genome sequence clarified that KF712 harbors the gene clusters coding for the catabolism of biphenyl and at least seven other aromatic compounds.

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره 8  شماره 

صفحات  -

تاریخ انتشار 2017