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Acta Crystallographica. Section E,... Dec 2023The title compound, CHFNOS, crystallizes in the monoclinic system, space group 2/, with = 8. As expected, the nine-membered heterobicyclic system is virtually planar...
The title compound, CHFNOS, crystallizes in the monoclinic system, space group 2/, with = 8. As expected, the nine-membered heterobicyclic system is virtually planar and the cyclo-hexyl group adopts a chair conformation. There is structural evidence for intra-molecular N-S⋯O chalcogen bonding between the benziso-thia-zolinone S atom and one O atom of the nitro group, approximately aligned along the extension of the covalent N-S bond [N-S⋯O = 162.7 (1)°]. In the crystal, the mol-ecules form centrosymmetric dimers through C-H⋯O weak hydrogen bonding between a C-H group of the electron-deficient benzene ring and the benzo-thia-zolinone carbonyl O atom with an (10) motif. In contrast to the previously described -acyl 7-nitro-5-(tri-fluoro-meth-yl)benzo[]iso-thia-zol-3(2)-ones, the title -cyclo-hexyl-methyl analogue does not inhibit growth of and .
PubMed: 38313133
DOI: 10.1107/S2056989023010137 -
Microbiology Spectrum Mar 2024Tuberculosis, a lung disease caused by (), remains a major global health problem ranking as the second leading cause of death from a single infectious agent. One of the...
UNLABELLED
Tuberculosis, a lung disease caused by (), remains a major global health problem ranking as the second leading cause of death from a single infectious agent. One of the major factors contributing toward success as a pathogen is its unique cell wall and its ability to counteract various arms of the host's immune response. A recent genome-scale study profiled a list of candidate genes that are predicted to be essential for survival of host-mediated responses. One candidate was FtsEX, a protein complex composed of an ATP-binding domain, FtsE, and a transmembrane domain, FtsX. FtsEX functions through interaction with a periplasmic hydrolase, RipC. Homologs of FtsEX exist in other bacteria and have been linked with playing a key role in regulating peptidoglycan hydrolysis during cell elongation and division. Here, we report on FtsE, FtsX, and RipC and their protective roles in stressful conditions. We demonstrate that the individual genes of FtsEX complex and RipC are not essential for survival in normal growth conditions but conditionally essential in low-salt media and antibiotic-treated media. Growth defects in these conditions were characterized by short and bulgy cells as well as elongated filamentous cells. Our results suggest that FtsE, FtsX, and RipC are required for both normal cell elongation and division and ultimately for survival in stressful conditions.
IMPORTANCE
Mycobacterial cell growth and division are coordinated with regulated peptidoglycan hydrolysis. Understanding cell wall gene complexes that govern normal cell division and elongation will aid in the development of tools to disarm the ability of mycobacteria to survive immune-like and antibiotic stresses. We combined genetic analyses and scanning electron microscopy to analyze morphological changes of mycobacterial FtsEX and RipC mutants in stressful conditions. We demonstrate that FtsE, FtsX, FtsEX, and RipC are conditionally required for the survival of during rifampicin treatment and in low-salt conditions. Growth defects in these conditions were characterized by short and bulgy cells as well as elongated filamentous cells. We also show that the FtsEX-RipC interaction is essential for the survival of in rifampicin. Our results suggest that FtsE, FtsX, and RipC are required for normal cell wall regulation and ultimately for survival in stressful conditions.
Topics: Cell Cycle Proteins; Bacterial Proteins; Rifampin; Peptidoglycan; Mycobacterium smegmatis; Osmolar Concentration; Anti-Bacterial Agents
PubMed: 38289931
DOI: 10.1128/spectrum.02515-23 -
Journal of Immunology (Baltimore, Md. :... Mar 2024In response to microbial infection, the nonclassical Ag-presenting molecule MHC class I-related protein 1 (MR1) presents secondary microbial metabolites to...
In response to microbial infection, the nonclassical Ag-presenting molecule MHC class I-related protein 1 (MR1) presents secondary microbial metabolites to mucosal-associated invariant T (MAIT) cells. In this study, we further characterize the repertoire of ligands captured by MR1 produced in Hi5 (Trichoplusia ni) cells from Mycobacterium smegmatis via mass spectrometry. We describe the (to our knowledge) novel MR1 ligand photolumazine (PL)V, a hydroxyindolyl-ribityllumazine with four isomers differing in the positioning of a hydroxyl group. We show that all four isomers are produced by M. smegmatis in culture and that at least three can induce MR1 surface translocation. Furthermore, human MAIT cell clones expressing distinct TCR β-chains differentially responded to the PLV isomers, demonstrating that the subtle positioning of a single hydroxyl group modulates TCR recognition. This study emphasizes structural microheterogeneity within the MR1 Ag repertoire and the remarkable selectivity of MAIT cell TCRs.
Topics: Humans; Mucosal-Associated Invariant T Cells; Receptors, Antigen, T-Cell, alpha-beta; Minor Histocompatibility Antigens; Histocompatibility Antigens Class I; Receptors, Antigen, T-Cell
PubMed: 38275935
DOI: 10.4049/jimmunol.2300609 -
Viruses Dec 2023Johne's disease (JD), a chronic infectious enteritis of ruminants, causes major economic losses in the dairy industry globally. This enteritis is caused by subsp....
Johne's disease (JD), a chronic infectious enteritis of ruminants, causes major economic losses in the dairy industry globally. This enteritis is caused by subsp. (MAP). Currently there is no cure for JD and test-based culling has proved ineffective at preventing the spread. To isolate new mycobacteriophages (mbps) that can potentially be used to control JD transmission and infection on dairy farms, we optimized an isolation protocol by fecal spiking and the testing of different isolation solution compositions. Using this protocol, we successfully enhanced the yield of mbps from spiked fecal samples, elevating it from less than 1% to 59%. With this method, we isolated 14 mbps from 475 environmental samples collected from MAP-positive dairy farms, after in-sample enrichment with MAP and the fast-growing . The sample sources included soil, manure pits, lactation barns, feces, milk, and drain water. After fingerprinting these mbps by restriction enzyme profiling, we concluded that 12 were distinct and novel. Further characterization of their host range revealed that eight were capable of lysing multiple MAP strains. We also studied the cross-resistance, lysogeny, the effect of pH and their antimycobacterial properties in milk replacer. Each novel mbp showed limited cross-resistance and prophage immunity and showed no reduction in the titer in a range of pHs after 4 h. The novel phages were also able to reduce the mycobacterial counts to zero after 8 h in milk replacer. In conclusion, these novel mbps could be considered to be used in the control strategies of JD on farms.
Topics: Female; Animals; Mycobacterium avium subsp. paratuberculosis; Mycobacteriophages; Bacteriophages; Farms; Enteritis
PubMed: 38257721
DOI: 10.3390/v16010020 -
International Journal of Molecular... Jan 2024Biofilm dispersal contributes to bacterial spread and disease transmission. However, its exact mechanism, especially that in the pathogen , is unclear. In this study,...
Biofilm dispersal contributes to bacterial spread and disease transmission. However, its exact mechanism, especially that in the pathogen , is unclear. In this study, the cellulase activity of the Rv0062 protein was characterized, and its effect on mycobacterial biofilm dispersal was analyzed by observation of the structure and components of Rv0062-treated biofilm in vitro. Meanwhile, the metabolite factors that induced cellulase-related biofilm dispersal were also explored with metabolome analysis and further validations. The results showed that Rv0062 protein had a cellulase activity with a similar optimum pH (6.0) and lower optimum temperature (30 °C) compared to the cellulases from other bacteria. It promoted mycobacterial biofilm dispersal by hydrolyzing cellulose, the main component of extracellular polymeric substrates of mycobacterial biofilm. A metabolome analysis revealed that 107 metabolites were significantly altered at different stages of biofilm development. Among them, a decrease in gamma-aminobutyric acid (GABA) promoted cellulase-related biofilm dispersal, and this effect was realized with the down-regulation of the bacterial signal molecule c-di-GMP. All these findings suggested that cellulase promotes mycobacterial biofilm dispersal and that this process is closely associated with biofilm metabolite alterations.
Topics: Cellulase; Mycobacterium tuberculosis; Biofilms; Cellulose; gamma-Aminobutyric Acid
PubMed: 38256125
DOI: 10.3390/ijms25021051 -
Nature Communications Jan 2024Ribosome hibernation is a key survival strategy bacteria adopt under environmental stress, where a protein, hibernation promotion factor (HPF), transitorily inactivates...
Ribosome hibernation is a key survival strategy bacteria adopt under environmental stress, where a protein, hibernation promotion factor (HPF), transitorily inactivates the ribosome. Mycobacterium tuberculosis encounters hypoxia (low oxygen) as a major stress in the host macrophages, and upregulates the expression of RafH protein, which is crucial for its survival. The RafH, a dual domain HPF, an orthologue of bacterial long HPF (HPF), hibernates ribosome in 70S monosome form, whereas in other bacteria, the HPF induces 70S ribosome dimerization and hibernates its ribosome in 100S disome form. Here, we report the cryo- EM structure of M. smegmatis, a close homolog of M. tuberculosis, 70S ribosome in complex with the RafH factor at an overall 2.8 Å resolution. The N- terminus domain (NTD) of RafH binds to the decoding center, similarly to HPF NTD. In contrast, the C- terminus domain (CTD) of RafH, which is larger than the HPF CTD, binds to a distinct site at the platform binding center of the ribosomal small subunit. The two domain-connecting linker regions, which remain mostly disordered in earlier reported HPF structures, interact mainly with the anti-Shine Dalgarno sequence of the 16S rRNA.
Topics: Ribosomal Proteins; Bacterial Proteins; RNA, Ribosomal, 16S; Ribosomes; Mycobacterium tuberculosis
PubMed: 38245551
DOI: 10.1038/s41467-024-44879-y -
Polymers Nov 2023The use of biocidal agents is a common practice for protection against biofouling in biomass-rich environments. In this paper, oligohexamethyleneguanidine (OHMG)...
The use of biocidal agents is a common practice for protection against biofouling in biomass-rich environments. In this paper, oligohexamethyleneguanidine (OHMG) polymer, known for its biocidal properties, was further modified with para-aminosalicylic acid (PAS) to enhance its properties against microorganisms coated with a lipid membrane. The structure of the product was confirmed by H NMR, C NMR, and FTIR spectroscopy. The values of the minimum inhibitory concentration (MIC) against ATCC 607 and 449 were found to be 1.40 and 1.05 μg/mL, respectively. The synthesized substance was used as an additive to the polymer matrix of the composite optical oxygen sensor material. A series of samples with different contents of OHMG-PAS was prepared using a co-dissolution method implying the fabrication of a coating from a solution containing both polymers. It turned out that the mutual influence of the components significantly affects the distribution of the indicator in the matrix, surface morphology, and contact angle. The optimal polymer content turned out to be wt.3%, at which point the water contact angle reaches almost 122°, and the fouling rate decreases by almost five times, which is confirmed by both the respiratory MTT assay and confocal microscopy with staining. This opens up prospects for creating stable and biofouling-resistant sensor elements for use in air tanks or seawater.
PubMed: 38231936
DOI: 10.3390/polym15234508 -
Microbiology Resource Announcements Feb 2024We report the discovery of two mycobacteriophages isolated from soil in Rock Hill, South Carolina. Ashballer has a genome sequence length of 52,231 bp, while Bombitas is...
We report the discovery of two mycobacteriophages isolated from soil in Rock Hill, South Carolina. Ashballer has a genome sequence length of 52,231 bp, while Bombitas is relatively larger at 110,129 bp. Both have siphovirus morphologies and have temperate lifecycles.
PubMed: 38231182
DOI: 10.1128/mra.00990-23 -
MBio Feb 2024Tuberculosis (TB) is a significant global public health threat. Despite the long-standing use of -aminosalicylic acid (PAS) as a second-line anti-TB drug, its resistance...
Tuberculosis (TB) is a significant global public health threat. Despite the long-standing use of -aminosalicylic acid (PAS) as a second-line anti-TB drug, its resistance mechanism remains unclear. In this study, we isolated 90 mutants of PAS-resistant (MTB) H37Ra in 7H11 solid medium and performed whole-genome sequencing, gene overexpression, transcription level comparison and amino acid level determination in MTB, and promoter activity by β-galactosidase assays in to elucidate the mechanism of PAS resistance. Herein, we found that 47 of 90 (52.2%) PAS-resistant mutants had nine different mutations in the intergenic region of () and . Beta-galactosidase assays confirmed that mutations increased promoter activity only for but not . Interestingly, overexpression of MetM or its homolog (MSMEI_1796) either by its promoter in 's direction or by exogenous expression in MTB induced PAS resistance in a methionine-dependent manner. Therefore, drug susceptibility results for the promoter mutants can be misleading when using standard 7H10 or 7H9 medium, which lacks methionine. At the metabolism level, PAS treatment led to higher intracellular methionine levels in the mutants than the wild type, antagonizing PAS and conferring resistance. Furthermore, 12 different mutations in the promoter were identified in clinical MTB strains. In summary, we found a novel mechanism of PAS resistance in MTB. Mutations in the (Rv3253c) promoter upregulate transcription and elevate intracellular methionine, which antagonize PAS. Our findings shed new light on the mechanism of PAS resistance in MTB and highlight issues with the current PAS susceptibility culture medium.IMPORTANCEAlthough -aminosalicylic acid (PAS) has been used to treat TB for more than 70 years, the understanding of PAS resistance mechanisms is still vague, living gaps in our ability to predict resistance and apply PAS effectively in clinical practice. This study aimed to address this knowledge gap by inducing PAS resistance in (MTB) using 7H11 medium and discovering a new PAS resistance mechanism. Our research revealed that spontaneous mutations occurring in the promoter region of the methionine transporting gene, , can upregulate the expression of , resulting in increased intracellular transport of methionine and consequently high-level resistance of to PAS. Notably, this resistance phenotype cannot be observed when using the commonly recommended 7H10 medium, possibly due to the lack of additional methionine supply compared with that when using the 7H11 medium. Mutations on the regulatory region of were also found in some clinical MTB strains. These findings may have important implications for the unexplained PAS resistance observed in clinical settings and provide insight into the failures of PAS treatment. Additionally, they underscore the importance of considering the choice of culture media when conducting drug susceptibility testing for MTB.
Topics: Mycobacterium tuberculosis; Aminosalicylic Acid; Microbial Sensitivity Tests; Drug Resistance, Bacterial; Antitubercular Agents; Mutation; Methionine; beta-Galactosidase
PubMed: 38179948
DOI: 10.1128/mbio.02073-23 -
BioRxiv : the Preprint Server For... Dec 2023Tuberculosis (TB) continues to be a major global health burden and kills over a million people annually. New immunization strategies are required for the development of...
Tuberculosis (TB) continues to be a major global health burden and kills over a million people annually. New immunization strategies are required for the development of an efficacious TB vaccine that can potentially induce sterilizing immunity. In this study, we first confirmed that various strains of the IKEPLUS vaccine confer a higher survival benefit than BCG in a murine model of intravenous (Mtb) infection. We have shown that there was a significant increase in the expression of the Rv0282 when IKEPLUS was grown in low zinc and iron containing Sauton medium. We confirmed on biofilm assays that zinc plays a vital role in the growth and formation of ( ) biofilms. IKEPLUS grown in low zinc media led to better protection of mice after intravenous challenge with very high dosage of Mtb. We also showed that various variants of IKEPLUS induced apoptotic cell-death of infected macrophages at a higher rate than wild type . We next attempted to determine if zinc containing ribosomal proteins such as rpmb2 could contribute to protective efficacy against Mtb infection. Since BCG has an established role in anti-mycobacterial efficacy, we boosted BCG vaccinated mice with rmpb2 but this did not lead to an increment in the protection mediated by BCG.
PubMed: 38168334
DOI: 10.1101/2023.12.11.571163