The rv2820c K114N mutation is related with capreomycin tolerance.

As one of the factors affecting the treatment outcomes, drug tolerance in mycobacteriosis has not been paid due attention. Genome-wide association studies on 607 Mycobacterium tuberculosis clinical isolates with phenotypic drug susceptibility test data revealed that a K114N mutation on the rv2820c gene was highly enriched in capreomycin-resistant isolates (32/213, 15.02%).

The T120P or M172V mutation on confers high level -aminosalicylic acid resistance in .

Although -aminosalicylic acid (PAS) has been used to treat tuberculosis for decades, mechanisms of resistance to this drug in () clinical isolates have not been thoroughly investigated. Previously, we found that decreased methylenetetrahydrofolate reductase (MTHFR) activity of Rv2172c led to increased sensitivity to antifolates in . In this study, we collected the genome-sequencing data of 173 PAS-resistant and 803 PAS-sensitive clinical isolates and analyzed mutations in those 976 isolates.

Competition between HPteGlu and HPtePAS Confers -Aminosalicylic Acid Resistance in .

Tuberculosis remains a serious challenge to human health worldwide. -Aminosalicylic acid (PAS) is an important anti-tuberculosis drug, which requires sequential activation by () dihydropteroate synthase and dihydrofolate synthase (DHFS, FolC). Previous studies showed that loss of function mutations of a thymidylate synthase coding gene caused PAS resistance in , but the mechanism is unclear.

Association between mutations in a region and -aminosalicylic acid resistance in clinical isolates.

Although -aminosalicylic acid (PAS) has been used to treat tuberculosis agent for decades, its mechanisms of resistance are still not thoroughly understood. Previously, sporadic studies showed that certain mutations in the region caused PAS resistance in , but a comprehensive analysis is lacking. Recently, we found a G-10A mutation in in a PAS-resistant clinical isolate, but it did not cause PAS resistance.

CycA-Dependent Glycine Assimilation Is Connected to Novobiocin Susceptibility in Escherichia coli.

Escherichia coli serine hydroxymethyltransferase (GlyA) converts serine to glycine, and mutants are auxotrophic for glycine. CycA is a transporter that mediates glycine uptake. Deleting in E.

Reducing the Periplasmic Glutathione Content Makes Escherichia coli Resistant to Trimethoprim and Other Antimicrobial Drugs.

Although glutathione (GSH) has been shown to influence the antimicrobial effects of many kinds of antibiotics, little is known about its role in relation to trimethoprim (TMP), a widely used antifolate. In this study, several genes related to glutathione metabolism were deleted in different Escherichia coli strains (i.e.

Decreased Methylenetetrahydrofolate Reductase Activity Leads to Increased Sensitivity to -Aminosalicylic Acid in Mycobacterium tuberculosis.

Tuberculosis (TB), caused by Mycobacterium tuberculosis, is one of the most fatal diseases in the world. Methylenetetrahydrofolate reductase (MTHFR) catalyzes the production of 5-methyltetrahydrofolate (5-CH-THF), which is required for the biosynthesis of methionine in bacteria. Here, we identified Rv2172c as an MTHFR in M.

Inactivation Converts Sulfonamides Into Bactericidal Compounds.

Folates are required for the biosynthesis of purines, thymine, methionine, glycine, and pantothenic acid, key metabolites that bacterial cells cannot survive without. Sulfonamides, which inhibit bacterial folate biosynthesis and are generally considered as bacteriostats, have been extensively used as broad-spectrum antimicrobials for decades. Here we show that, deleting in and other bacterial species converted sulfamethoxazole from a bacteriostat into a bactericide.

MgrB Inactivation Confers Trimethoprim Resistance in .

After several decades of use, trimethoprim (TMP) remains one of the key access antimicrobial drugs listed by the World Health Organization. To circumvent the problem of trimethoprim resistance worldwide, a better understanding of drug-resistance mechanisms is required. In this study, we screened the single-gene knockout library of , and identified and other several genes involved in trimethoprim resistance.

Characterization of Mutations and Prediction of PZA Resistance in Clinical Isolates From Chongqing, China.

Pyrazinamide (PZA) is widely used to treat drug-sensitive or multidrug resistance tuberculosis. However, conventional PZA susceptibility tests of clinical isolates are rather difficult because of the requirement of acid pH. Since resistance to pyrazinamide is primary mediated by mutation of , an alternative way of PZA susceptibility test is to analyze the pyrazinamidase activities of clinical isolates.

Mutations of folC cause increased susceptibility to sulfamethoxazole in Mycobacterium tuberculosis.

Previous studies showed that mutation of folC caused decreased expression of the dihydropteroate synthase encoding gene folP2 in Mycobacterium tuberculosis (M. tuberculosis). We speculated that mutation of folC in M.

A single regulator NrtR controls bacterial NAD homeostasis via its acetylation.

Nicotinamide adenine dinucleotide (NAD) is an indispensable cofactor in all domains of life, and its homeostasis must be regulated tightly. Here we report that a Nudix-related transcriptional factor, designated MsNrtR (MSMEG_3198), controls the pathway of NADbiosynthesis in , a non-tuberculosis . The integrated evidence and confirms that MsNrtR is an auto-repressor, which negatively controls the NADbiosynthetic pathway.

Fatty acylCoA synthetase FadD13 regulates proinflammatory cytokine secretion dependent on the NF-κB signalling pathway by binding to eEF1A1.

Mycobacterium tuberculosis (Mtb) manipulates multiple host defence pathways to survive and persist in host cells. Understanding Mtb-host cell interaction is crucial to develop an efficient means to control the disease. Here, we applied the Mtb proteome chip, through separately interacting with H37Ra and H37Rv stimulated macrophage lysates, screened 283 Mtb differential proteins.

MgrB affects the acid stress response of Escherichia coli by modulating the expression of iraM.

Although MgrB is established to be a feedback inhibitor of the PhoP/Q system in Escherichia coli, the biological functions of MgrB remain largely unknown. To explore new functions of MgrB, a comparative transcriptome analysis was performed (E. coli K-12 W3110 ΔmgrB vs E.

Identification of Serine 119 as an Effective Inhibitor Binding Site of M. tuberculosis Ubiquitin-like Protein Ligase PafA Using Purified Proteins and M. smegmatis.

Owing to the spread of multidrug resistance (MDR) and extensive drug resistance (XDR), there is a pressing need to identify potential targets for the development of more-effective anti-M. tuberculosis (Mtb) drugs. PafA, as the sole Prokaryotic Ubiquitin-like Protein ligase in the Pup-proteasome System (PPS) of Mtb, is an attractive drug target.

Systematic Identification of Effectors Reveals that BfrB Suppresses Innate Immunity.

(Mtb) has evolved multiple strategies to counter the human immune system. The effectors of Mtb play important roles in the interactions with the host. However, because of the lack of highly efficient strategies, there are only a handful of known Mtb effectors, thus hampering our understanding of Mtb pathogenesis.

Structural analysis of the regulatory mechanism of MarR protein Rv2887 in M. tuberculosis.

MarR family proteins are transcriptional regulators that control expression of bacterial proteins involved in metabolism, virulence, stress responses and multi-drug resistance, mainly via ligand-mediated attenuation of DNA binding. Greater understanding of their underlying regulatory mechanism may open up new avenues for the effective treatment of bacterial infections. To gain molecular insight into the mechanism of Rv2887, a MarR family protein in M.

Deletion of Causes Increased Sensitivity to -Aminosalicylic Acid and Sulfamethoxazole in Mycobacterium tuberculosis.

Although the folate biosynthesis pathway has been well studied in bacteria, little is known about its regulation. In the present study, the gene in was deleted. Subsequent drug susceptibility tests revealed that the Δ strain was more sensitive to -aminosalicylic acid (PAS) and sulfamethoxazole.

The Ser/Thr Protein Kinase Protein-Protein Interaction Map of .

(Mtb) is the causative agent of tuberculosis, the leading cause of death among all infectious diseases. There are 11 eukaryotic-like serine/threonine protein kinases (STPKs) in Mtb, which are thought to play pivotal roles in cell growth, signal transduction and pathogenesis. However, their underlying mechanisms of action remain largely uncharacterized.

A Cassette Containing Thiostrepton, Gentamicin Resistance Genes, and sequences Is Effective in Construction of Recombinant Mycobacteria.

The genetic manipulation of genome is limited by the availability of selection markers. Spontaneous resistance mutation rate of to the widely used kanamycin is relatively high which often leads to some false positive transformants. Due to the few available markers, we have created a cassette containing thiostrepton resistance gene () for selection in and BCG, and gentamicin resistance gene () for and mc155, flanked with sequences recognized by the Xer system of mycobacteria.

Deletion of Causes Increased Susceptibility to Antifolates in Escherichia coli and Salmonella enterica.

Co-trimoxazole, a fixed-dose combination of sulfamethoxazole (SMX) and trimethoprim (TMP), has been used for the treatment of bacterial infections since the 1960s. Since it has long been assumed that the synergistic effects between SMX and TMP are the consequence of targeting 2 different enzymes of bacterial folate biosynthesis, 2 genes ( and ) involved in the folate biosynthesis of were deleted, and their effects on the susceptibility to antifolates were tested. The results showed that the deletion of resulted in a lag of growth in minimal medium and increased susceptibility to both SMX and TMP.

Anti-folates potentiate bactericidal effects of other antimicrobial agents.

Synergies between sulfonamides and other antimicrobial agents have long been reported, but the reason still remains unclear. Previously, Vilchèze et al. found that, sulfamethoxazole (SMX) could potentiate the bacterialcidal activity of isoniazid (INH) and rifampin (RIF) in Mycobacterium tuberculosis.

Lysine acetylation regulates the activity of Escherichia coli pyridoxine 5'-phosphate oxidase.

Nɛ-lysine acetylation is one of the most abundant post-translational modifications in eukaryote and prokaryote. Protein acetylome of Escherichia coli has been screened using mass spectrometry (MS) technology, and many acetylated proteins have been identified, including the pyridoxine 5'-phosphate oxidase (EcPNPOx), but the biological roles played by lysine acetylation in EcPNPOx still remain unknown. In this study, EcPNPOx was firstly overexpressed and purified, and two acetylated lysine residues were identified by the subsequent liquid chromatography-tandem mass spectrometry analysis.