Characterization of the DNA mismatch repair proteins MutS and MutL in a hypermutator Acinetobacter baumannii

Genes and Proteomes Associated With Increased Mutation Frequency and Multidrug Resistance of Naturally Occurring Mismatch Repair-Deficient Salmonella Hypermutators

The emergence of antibiotic-resistant Salmonella through mutations led to mismatch repair (MMR) deficiency that represents a potential hazard to public health. Here, four representative MMR-deficient Salmonella hypermutator strains and Salmonella Typhimurium LT2 were used to comprehensively reveal the influence of MMR deficiency on antibiotic resistance among Salmonella. Our results indicated that the mutation frequency ranged from 3.39 × 10^–4 to 5.46 × 10^–2 in the hypermutator. Mutation sites in MutS, MutL, MutT, and UvrD of the four hypermutators were all located in the essential and core functional regions. Mutation frequency of the hypermutator was most highly correlated with the extent of mutation in MutS. Mutations in MMR genes (mutS, mutT, mutL, and uvrD) were correlated with increased mutation in antibiotic resistance genes, and the extent of antibiotic resistance was significantly correlated with the number of mutation sites in MutL and in ParC. The number of mutation sites in MMR genes and antibiotic resistance genes exhibited a significant positive correlation with the number of antibiotics resisted and with expression levels of mutS, mutT, and mutL. Compared to Salmonella Typhimurium LT2, a total of 137 differentially expressed and 110 specifically expressed proteins were identified in the four hypermutators. Functional enrichment analysis indicated that the proteins significantly overexpressed in the hypermutators primarily associated with translation and stress response. Interaction network analysis revealed that the ribosome pathway might be a critical factor for high mutation frequency and multidrug resistance in MMR-deficient Salmonella hypermutators. These results help elucidate the mutational dynamics that lead to hypermutation, antibiotic resistance, and activation of stress response pathways in Salmonella.

Therapeutics and prospects of Interleukin 2

Interleukin-2 was discovered back in 1983 as an autocrine growth factor for cultured T cells and was the first biological product created through the use of recombinant DNA. IL-2 tumor immunotherapy performed the first historical clinical demonstration of the possibility to cause an effective anticancer immune reaction, mediated by cytotoxic lymphocytes activated from IL-2 stimulation. The Interleukin 2 receptor is a heterotrimeric protein that is composed of three peptide chains: the alpha chain, the beta chain and the gamma chain of the common cytokine receptor. There are 3 majors’ ways of interfering with the IL-2/IL-2R to use it as treatments: Antibodies, Aptamers, and punctual mutagenesis. Recent studies have shown, that Il-2 therapies for cancer, specifically targets restoring the individual’s natural antitumor immune response. HIV directed treatments have demonstrated the necessity of introducing the IL-2 complemented with the patient’s antiretroviral therapy.