Characterization and Structure Prediction of Partial Length Protein Sequences of pcoA, pcoR and chrB Genes from Heavy Metal Resistant Bacteria from the Klip River, South Africa

Abstract

The Klip River has suffered from severe anthropogenic effects from industrial activities such as mining. Long-term exposure to heavy metal pollution has led to the development of heavy metal resistant strains of Pseudomonas sp. KR23, Lysinibacillus sp. KR25, and E. coli KR29. The objectives of this study were to characterize the genetics of copper and chromate resistance of the isolates. Copper and chromate resistance determinants were cloned and sequenced. Open reading frames (ORFs) related to the genes CopA and CopR were identified in E. coli KR29, PcoA in Lysinibacillus sp. KR25 and none related to chromate resistance were detected. The 3D-models predicted by I-TASSER disclose that the PcoA proteins consist of β-sheets, which form a part of the cupredoxin domain of the CopA copper resistance family of genes. The model for PcoR_29 revealed the presence of a helix turn helix; this forms part of a DNA binding protein, which is part of a heavy metal transcriptional regulator. The bacterial strains were cured using ethidium bromide. The genes encoding for heavy metal resistance and antibiotic resistance were found to be located on the chromosome for both Pseudomonas sp. (KR23) and E. coli (KR29). For Lysinibacillus (KR25) the heavy metal resistance determinants are suspected to be located on a mobile genetic element, which was not detected using gel electrophoresis.

Phenotypic and genotypic investigation of the heavy metal resistance in Escherichia coliisolates recovered from cattle stool samples

“…More than one operon and gene are responsible for copper resistance in bacteria [8,12]. Although Chihomvu et al [11] detected pcoR gene in the E. coli isolates in an aquatic system of industrial pollutants, Dell' Amico et al [5] detected phenotypic resistance to copper in bacteria isolated from soil. However, he could not detect the presence of the pcoR gene using the PCR method and reported that there might be other genes responsible for resistance.…”

“…Then, deionized distilled water was added until the total volume became 25 µL. For thermal cycling of zntA, analyses were made according to Becerra-Castro et al [21], and for pcoR, the analyses were made according to Chihomvu et al [11]. As all the isolates were sensitive to mercury, the merA gene was not analyzed.…”

“…Highly-developed organisms are influenced by the toxic effects of heavy metals at a significant level. However, similar influences are not observed in many microorganisms [9] since bacteria continue their lives with the help of resistance systems they develop in environments that include intense metal contamination [10][11][12]. Although metal resistance has not received the same level of attention as antibiotic resistance in veterinary medicine, it is still a significant reality.…”

Do environmentally induced DNA variations mediate adaptation in Aspergillus flavus exposed to chromium stress in tannery sludge?

“…In congruence, a study in Pseudomonas corrugata suggested that recG helicase played a crucial role in chromium tolerance by dismissing PAL lesions caused by Cr (VI)/Cr (III) [ 58 ]. The chrE gene encodes a rhodanese type enzyme [ 59 ]. Rhodanese protein subfamilies are suggested to be involved in different biological functions including cyanide detoxification, arsenic resistance and chromate responsive DNA-binding regulator.…”

Resistance to Antibiotics, Biocides, Preservatives and Metals in Bacteria Isolated from Seafoods: Co-Selection of Strains Resistant or Tolerant to Different Classes of Compounds

“…The czcD gene involved in the regulation of the CZC zinc, cobalt, and cadmium efflux system was investigated by PCR according to Medardus et al ( 2014 ). The chromate resistance gene chrB was investigated as described by Chihomvu et al ( 2015 ) and Nies et al ( 1990 ).…”