Functional characterization of a cadmium resistance operon in Staphylococcus aureus ATCC12600: CadC does not function as a repressor Original paper
Researched by:
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Divine Aleru
ID
Divine Aleru
Read MoreI am a biochemist with a deep curiosity for the human microbiome and how it shapes human health, and I enjoy making microbiome science more accessible through research and writing. With 2 years experience in microbiome research, I have curated microbiome studies, analyzed microbial signatures, and now focus on interventions as a Microbiome Signatures and Interventions Research Coordinator.
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Metals
Metals
Heavy metals influence microbial pathogenicity in two ways: they can be toxic to microbes by disrupting cellular functions and inducing oxidative stress, and they can be exploited by pathogens to enhance survival, resist treatment, and evade immunity. Understanding metal–microbe interactions supports better antimicrobial and public health strategies.
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Microbes
Microbes
Microbes are microscopic organisms living in and on the human body, shaping health through digestion, vitamin production, and immune protection. When microbial balance is disrupted, disease can occur. This guide explains key microbe types—bacteria, viruses, fungi, protozoa, and archaea—plus major pathogenic and beneficial examples.
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Divine Aleru
Read More
Researched by:
-
Divine Aleru
ID
Divine Aleru
Read More
Microbiome Signatures identifies and validates condition-specific microbiome shifts and interventions to accelerate clinical translation. Our multidisciplinary team supports clinicians, researchers, and innovators in turning microbiome science into actionable medicine.
Divine Aleru
What was studied?
This study focused on the functional characterization of a cadmium resistance operon in Staphylococcus aureus ATCC12600. The operon, which consists of two key genes, cadC and cadA, was identified in a transposon mutagenesis library. The research aimed to investigate the role of these genes in cadmium and zinc resistance and explore the genetic and functional mechanisms behind the resistance, particularly focusing on the efflux mechanism.
Who was studied?
The study involved Staphylococcus aureus ATCC12600, a non-methicillin-resistant strain. The operon was compared to similar operons found in methicillin-resistant strains (MRSA), particularly S. aureus MRSA252, and examined the gene expression and resistance properties. The research also involved mutant strains, including those with transposon disruptions in cadC, to better understand the functional impact of each gene within the operon.
Most important findings
The S. aureus ATCC12600 strain containing the cadC-positive plasmid showed high levels of resistance to cadmium sulfate, with minimal growth reduction even in the presence of 250 mg/ml cadmium sulfate. In contrast, the cadC-mutant strains exhibited significantly lower resistance. This suggested that cadC plays a crucial role in cadmium efflux, although the absence of CadC did not completely block cadmium efflux, as the cadA gene, even in the absence of cadC, still contributed to a lower level of resistance. Additionally, the study found that the CadC protein from S. aureus ATCC12600 did not function as a transcriptional repressor, unlike the CadC protein from pI258, which had been previously identified as a repressor.
Key implications
The findings demonstrate that the cadC gene in S. aureus ATCC12600 is integral to cadmium resistance, specifically through its involvement in cadmium efflux, but it does not operate as a repressor as seen in other strains. This research provides new insights into cadmium resistance mechanisms in S. aureus and highlights the differences between resistance mechanisms in non-MRSA and MRSA strains. Understanding these resistance pathways may aid in developing strategies for tackling cadmium toxicity, particularly in environments contaminated with heavy metals.
Staphylococcus aureus (S. Aureus)
Staphylococcus aureus is a versatile skin and mucosal commensal that can transition into a highly virulent pathobiont. Known for its immune-evasive strategies, toxin production, and antibiotic resistance, it plays a significant role in chronic infections and microbiome imbalance.