Metal Resistance-Related Genes are Differently Expressed in Response to Copper and Zinc Ion in Six Acidithiobacillus ferrooxidans Strains

Abstract

Metal resistance of acidophilic bacteria is very significant during bioleaching of copper ores since high concentration of metal is harmful to the growth of microorganisms. The resistance levels of six Acidithiobacillus ferrooxidans strains to 0.15 M copper and 0.2 M zinc were investigated, and eight metal resistance-related genes (afe-0022, afe-0326, afe-0329, afe-1143, afe-0602, afe-0603, afe-0604, and afe-1788) were sequenced and analyzed. The transcriptional expression levels of eight possible metal tolerance genes in six A. ferrooxidans strains exposed to 0.15 M Cu(2+) and 0.2 M Zn(2+) were determined by real-time quantitative PCR (RT-qPCR), respectively. The copper resistance levels of six A. ferrooxidans strains declined followed by DY26, DX5, DY15, GD-B, GD-0, and YTW. The zinc tolerance levels of six A. ferrooxidans strains exposed to 0.2 M Zn(2+) from high to low were YTW > GD-B > DY26 > GD-0 > DX5 > DY15. Seven metal tolerance-related genes all presented in the genome of six strains, except afe-0604. The metal resistance-related genes showed different transcriptional expression patterns in six A. ferrooxidans strains. The expression of gene afe-0326 and afe-0022 in six A. ferrooxidans strains in response to 0.15 M Cu(2+) showed the same trend with the resistance levels. The expression levels of genes afe-0602, afe-0603, afe-0604, and afe-1788 in six strains response to 0.2 M Zn(2+) did not show a clear correlation between the zinc tolerance levels of six strains. According to the results of RT-qPCR and bioinformatics analysis, the proteins encoded by afe-0022, afe-0326, afe-0329, and afe-1143 were related to Cu(2+) transport of A. ferrooxidans strains.

Oxidative Stress Induced by Metal Ions in Bioleaching of LiCoO2 by an Acidophilic Microbial Consortium

“…Several researchers have proved that there exist different tolerances of AMC for various metal ions such as Mo 6+ and V 4+ (Pradhan et al, 2009), Cu 2+ (Navarro et al, 2013), and Zn 2+ (Chen et al, 2004;Xin et al, 2012) based on diverse mechanisms (Wu et al, 2014). However, few have reported about the tolerance of AMC to high concentrations of Li + and Co 2+ .…”

Resistência Bacteriana Aos Antibióticos: Papel Dos Sistemas De Integridade Da Parede Celular

“…As proteínas de transporte de íons desempenham um papel fundamental na resistência bacteriana aos agentes antimicrobianos. Essas proteínas contribuem para a capacidade das bactérias de se adaptarem e sobreviverem em presença de altas concentrações de íons tóxicos, incluindo metais pesados e agentes antimicrobianos (WU et al, 2014).…”

“…Essas proteínas, pertencentes à família Cus e Znt, respectivamente, estão envolvidas no transporte ativo desses metais para fora das células bacterianas, reduzindo assim sua concentração intracelular tóxica. A resistência a metais pesados é frequentemente associada à resistência a antibióticos, pois as proteínas de resistência também podem expulsar alguns agentes antimicrobianos através de mecanismos semelhantes (WU et al, 2014).…”

Understanding Stress Response to High-Arsenic Gold-Bearing Sulfide Concentrate in Extremely Metal-Resistant Acidophile Sulfobacillus thermotolerans

“…Most studies of the heavy metal resistance mechanisms in acidophiles, including proteomic research, have focused on At. ferrooxidans [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ] and some other acidophilic bacteria and archaea: At. thiooxidans , At.…”