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Antibiotics (Basel, Switzerland) Jun 2024The rising incidence of extensively drug-resistant (XDR) , including carbapenem- and colistin-resistant strains, leads to the limitation of available effective...
The rising incidence of extensively drug-resistant (XDR) , including carbapenem- and colistin-resistant strains, leads to the limitation of available effective antibiotics. , known as chewing tea, is produced from var. or Assam tea leaves fermentation. Previous studies revealed that the extract of contains various phenolic and flavonoid compounds with numerous biological activities including antibacterial activity. However, the antibacterial activity of against XDR bacteria especially colistin-resistant strains had not been investigated. In this study, the compositions of phenolic and flavonoid compounds in fresh, steamed, and fermented Assam tea leaves were examined by HPLC, and their antibacterial activities were evaluated by the determination of the MIC and MBC. Pyrogallol was detected only in the extract from and showed the highest activities with an MIC of 0.25 mg/mL and an MBC of 0.25-0.5 mg/mL against methicillin-susceptible , methicillin-resistant , ATCC 25922, colistin-resistant , and colistin-resistant . The effects on morphology and proteomic changes in NH54 treated with extract were characterized by SEM and label-free quantitative shotgun proteomics analysis. The results revealed that extract caused the decrease in bacterial cell wall integrity and cell lysis. The up- and downregulated expression with approximately a 2 to >5-fold change in proteins involved in peptidoglycan synthesis and outer membrane, carbohydrate, and amino acid metabolism were identified. These findings suggested that containing pyrogallol and other secondary metabolites from fermentation has potential as an alternative candidate with an antibacterial agent or natural active pharmaceutical ingredient against XDR bacteria including colistin-resistant bacteria.
PubMed: 38927202
DOI: 10.3390/antibiotics13060536 -
The Journal of Antibiotics Jun 2024A novel actinomycete, designated as TPMA0078, was isolated from a soil sample collected in Shinjuku, Tokyo, Japan. 16S rRNA gene sequence analysis indicated that strain...
A novel actinomycete, designated as TPMA0078, was isolated from a soil sample collected in Shinjuku, Tokyo, Japan. 16S rRNA gene sequence analysis indicated that strain TPMA0078 belongs to the genus Actinoplanes and is closely related to Actinoplanes regularis IFO 12514 (99.86% 16S rRNA gene sequence similarity). The spores of strain TPMA0078 were motile, and the sporangia were cylindrical. The diamino acids in the cell wall peptidoglycan of strain TPMA0078 were meso-diaminopimelic acid and 3OH-meso-diaminopimelic acid. Whole-cell sugars were glucose and mannose, with galactose as a minor component. The major cellular fatty acids identified were iso-C, iso-C, and anteiso-C. The predominant menaquinone was MK-9(H), and the principal polar lipid was phosphatidylethanolamine. These chemotaxonomic properties of strain TPMA0078 were consistent with those of Actinoplanes. Meanwhile, digital DNA-DNA hybridization and average nucleotide identity values showed low relatedness between strain TPMA0078 and A. regularis NBRC 12514. Furthermore, several phenotypic properties of strain TPMA0078 distinguished it from those of closely related species. Based on its genotypic and phenotypic characteristics, strain TPMA0078 represents a novel species of the genus Actinoplanes, for which the name Actinoplanes kirromycinicus sp. nov. is proposed. The type strain is TPMA0078 (=NBRC 116422 = TBRC 18262).
PubMed: 38926493
DOI: 10.1038/s41429-024-00756-w -
Nature Communications Jun 2024Most rod-shaped bacteria elongate by inserting new cell wall material into the inner surface of the cell sidewall. This is performed by class A penicillin binding...
Most rod-shaped bacteria elongate by inserting new cell wall material into the inner surface of the cell sidewall. This is performed by class A penicillin binding proteins (PBPs) and a highly conserved protein complex, the elongasome, which moves processively around the cell circumference and inserts long glycan strands that act as barrel-hoop-like reinforcing structures, thereby giving rise to a rod-shaped cell. However, it remains unclear how elongasome synthesis dynamics and termination events are regulated to determine the length of these critical cell-reinforcing structures. To address this, we developed a method to track individual elongasome complexes around the entire circumference of Bacillus subtilis cells for minutes-long periods using single-molecule fluorescence microscopy. We found that the B. subtilis elongasome is highly processive and that processive synthesis events are frequently terminated by rapid reversal or extended pauses. We found that cellular levels of RodA regulate elongasome processivity, reversal and pausing. Our single-molecule data, together with stochastic simulations, show that elongasome dynamics and processivity are regulated by molecular motor tug-of-war competition between several, likely two, oppositely oriented peptidoglycan synthesis complexes associated with the MreB filament. Altogether these results demonstrate that molecular motor tug-of-war is a key regulator of elongasome dynamics in B. subtilis, which likely also regulates the cell shape via modulation of elongasome processivity.
Topics: Bacillus subtilis; Cell Wall; Bacterial Proteins; Penicillin-Binding Proteins; Peptidoglycan; Microscopy, Fluorescence; Single Molecule Imaging; Molecular Motor Proteins
PubMed: 38926336
DOI: 10.1038/s41467-024-49785-x -
Drug Discoveries & Therapeutics Jun 2024Staphylococcus aureus, a Gram-positive bacterium, causes inflammatory skin diseases, such as atopic dermatitis, and serious systemic diseases, such as sepsis. In the...
Staphylococcus aureus, a Gram-positive bacterium, causes inflammatory skin diseases, such as atopic dermatitis, and serious systemic diseases, such as sepsis. In the skin and nasal environment, peptidoglycan (PGN)-degrading enzymes, including lysozyme and lysostaphin, affects S. aureus PGN. However, the effects of PGN-degrading enzymes on the acute innate immune-inducing activity of S. aureus have not yet been investigated. In this study, we demonstrated that PGN-degrading enzymes induce acute silkworm hemolymph melanization by S. aureus. Insoluble fractions of S. aureus treated with lysozyme, lysostaphin, or both enzymes, were prepared. Melanization of the silkworm hemolymph caused by the injection of these insoluble fractions was higher than that of S. aureus without enzyme treatment. These results suggest that structural changes in S. aureus PGN caused by PGN-degrading enzymes affect the acute innate immune response in silkworms.
PubMed: 38925960
DOI: 10.5582/ddt.2024.01026 -
Developmental and Comparative Immunology Jun 2024To overcome bacterial invasion and infection, animals have evolved various antimicrobial effectors such as antimicrobial peptides and lysozymes. Although C. elegans is...
To overcome bacterial invasion and infection, animals have evolved various antimicrobial effectors such as antimicrobial peptides and lysozymes. Although C. elegans is exposed to a variety of microbes due to its bacterivorous lifestyle, previous work on the components of its immune system mainly based on the description of transcriptional changes during bacterial challenges. Very few effector components of its immune system have been characterized so far. To investigate the role of lysozymes in terms of antibacterial defense and digestion, we studied a member of the widely neglected family of C. elegans invertebrate lysozymes (ILYS). We focused on the so far virtually undescribed ILYS-5, which we purified from protein extracts of C. elegans tracing its peptidoglycan-degrading activity and localized the tissue expression of the gene in vivo using a translational reporter construct. We recombinantly synthesized ILYS-5 and determined the physicochemical activity optimum and the antibacterial spectrum of a lysozyme from C. elegans for the first time. With an activity optimum at low ionic strength (≤100 mM) and at acidic pH (≤ pH 4.0), ILYS-5 is likely to be involved in killing and digestion of bacteria within acidified phagolysosomes and acidic regions of the gut, presumably secreted by lysosome-like vesicles. This notion is supported by potent activity against various live Gram-positive and Gram-negative bacteria. Notably, members of the natural associated microbiome of C. elegans are substantially less susceptible to ILYS-5. Ablation of the ilys-5 gene resulted in reduction of lifespan and fertility when cultured on the standard food bacterium Escherichia coli OP50, whereas exposure of the ilys-5 knock-out mutant to the host-associated bacterium Pseudomonas lurida MYb11 did not have a clear effect. These findings indicate a role of ILYS-5 in immunity and nutrition and a co-evolved adaptation of host and bacteria to the mutualistic nature of their interaction.
PubMed: 38925432
DOI: 10.1016/j.dci.2024.105220 -
International Journal of Biological... Jun 2024Highly stable, colloidal iron oxide nanoparticles with an oxyhydroxide-like surface were used as bacteria-capturing nano-baits. Peptidoglycan isolated from Listeria spp...
Highly stable, colloidal iron oxide nanoparticles with an oxyhydroxide-like surface were used as bacteria-capturing nano-baits. Peptidoglycan isolated from Listeria spp was used as bacteria polysaccharide model, and the nanoparticle binding was characterized showing a Langmuir isotherm constant, K, equal to 50 ± 3 mL mg. The chemical affinity was further supported by dynamic light scattering, transmission electron microscopy, and infrared and UV-Vis data, pointing at the occurrence of extended, coordinative multiple point bindings. The interaction with Gram (+) (Listeria spp) and Gram (-) (Aeromonas veronii) bacteria was shown to be effective and devoid of any toxic effect. Moreover, a real sample, containing a population of several oligotrophic bacteria strains, was incubated with 1 g L of nanoparticle suspension, in the absence of agitation, showing a 100 % capture efficiency, according to plate count. A nanoparticle regeneration method was developed, despite the known irreversibility of such bacterial-nanosurface binding, restoring the bacteria capture capability. This nanomaterial represents a competitive option to eliminate microbiological contamination in water as an alternative strategy to antibiotics, aimed at reducing microbial resistance dissemination. Finally, beyond their excellent features in terms of colloidal stability, binding performances, and biocompatibility this nanoparticle synthesis is cost effective, scalable, and environmentally sustainable.
PubMed: 38925181
DOI: 10.1016/j.ijbiomac.2024.133415 -
Current Biology : CB Jun 2024The UV resistance of bacterial endospores is an important quality supporting their survival in inhospitable environments and therefore constitutes an essential driver of...
The UV resistance of bacterial endospores is an important quality supporting their survival in inhospitable environments and therefore constitutes an essential driver of the ecological success of spore-forming bacteria. Nevertheless, the variability and evolvability of this trait are poorly understood. In this study, directed evolution and genetics approaches revealed that the Bacillus cereus pdaA gene (encoding the endospore-specific peptidoglycan-N-acetylmuramic acid deacetylase) serves as a contingency locus in which the expansion and contraction of short tandem repeats can readily compromise (PdaA) or restore (PdaA) the pdaA open reading frame. Compared with B. cereus populations in the PdaA state, populations in the PdaA state produced a lower yield of viable endospores but endowed them with vastly increased UV resistance. Moreover, selection pressures based on either quantity (i.e., yield of viable endospores) or quality (i.e., UV resistance of viable endospores) aspects could readily shift populations between PdaA and PdaA states, respectively. Bioinformatic analysis also revealed that pdaA homologs within the Bacillus and Clostridium genera are often equipped with several short tandem repeat regions, suggesting a wider implementation of the pdaA-mediated phase variability in other sporeformers as well. These results for the first time reveal (1) pdaA as a phase-variable contingency locus in the adaptive evolution of endospore properties and (2) bet-hedging between what appears to be a quantity versus quality trade-off in endospore crops.
PubMed: 38925118
DOI: 10.1016/j.cub.2024.05.067 -
Molecular Microbiology Jun 2024In the model organism Bacillus subtilis, a signaling protease produced in the forespore, SpoIVB, is essential for the activation of the sigma factor σ, which is...
In the model organism Bacillus subtilis, a signaling protease produced in the forespore, SpoIVB, is essential for the activation of the sigma factor σ, which is produced in the mother cell as an inactive pro-protein, pro-σ. SpoIVB has a second function essential to sporulation, most likely during cortex synthesis. The cortex is composed of peptidoglycan (PG) and is essential for the spore's heat resistance and dormancy. Surprisingly, the genome of the intestinal pathogen Clostridioides difficile, in which σ is produced without a pro-sequence, encodes two SpoIVB paralogs, SpoIVB1 and SpoIVB2. Here, we show that spoIVB1 is dispensable for sporulation, while a spoIVB2 in-frame deletion mutant fails to produce heat-resistant spores. The spoIVB2 mutant enters sporulation, undergoes asymmetric division, and completes engulfment of the forespore by the mother cell but fails to synthesize the spore cortex. We show that SpoIIP, a PG hydrolase and part of the engulfasome, the machinery essential for engulfment, is cleaved by SpoIVB2 into an inactive form. Within the engulfasome, the SpoIIP amidase activity generates the substrates for the SpoIID lytic transglycosylase. Thus, following engulfment completion, the cleavage and inactivation of SpoIIP by SpoIVB2 curtails the engulfasome hydrolytic activity, at a time when synthesis of the spore cortex peptidoglycan begins. SpoIVB2 is also required for normal late gene expression in the forespore by a currently unknown mechanism. Together, these observations suggest a role for SpoIVB2 in coordinating late morphological and gene expression events between the forespore and the mother cell.
PubMed: 38922761
DOI: 10.1111/mmi.15291 -
International Journal of Systematic and... Jun 2024A Gram-stain-positive, rod-shaped, aerobic, motile bacterium, J379, was isolated from radioactive water spring C1, located in a former silver-uranium mine in the Czech...
A Gram-stain-positive, rod-shaped, aerobic, motile bacterium, J379, was isolated from radioactive water spring C1, located in a former silver-uranium mine in the Czech Republic. This slow-growing strain exhibited optimal growth at 24-28 °C on solid media with <1 % salt concentration and alkaline pH 8-10. The only respiratory quinone found in strain J379 was MK-7(H). C ω9 (60.9 %), C (9.4 %), C and alcohol-C (both 6.2 %) were found to be the major fatty acids. The peptidoglycan contained directly cross-linked -diaminopimelic acid. Phylogenetic reconstruction based on the 16S rRNA gene sequences and the core-genome analysis revealed that strain J379 forms a separate phylogenetic lineage within the recently amended order . A comparison of the 16S rRNA gene sequences between strain J379 and other members of the order showed <96 % similarity. This analysis revealed that the closest type strains were D16/0 /H6 (95.2 %), 0166_1 (94.9 %) and KV-962 (94.5 %). Whole-genome analysis showed that the closest type strain was BR7-21 with an average nucleotide identity of 78 %, average amino acid identity of 63.2 % and percentage of conserved proteins of 48.2 %. The G+C content of the J379 genomic DNA was 71.7 mol%. Based on the phylogenetic and phylogenomic data, as well as its physiological characteristics, strain J379 is proposed to represent a type strain (DSM 113746=CCM 9300) of gen. nov. sp. nov. within the family .
Topics: Phylogeny; RNA, Ribosomal, 16S; Bacterial Typing Techniques; Fatty Acids; DNA, Bacterial; Sequence Analysis, DNA; Base Composition; Mining; Czech Republic; Peptidoglycan; Diaminopimelic Acid; Vitamin K 2; Silver; Water Microbiology
PubMed: 38922323
DOI: 10.1099/ijsem.0.006432 -
Toxics May 2024Acrylamide (AA) and 5-hydroxymethylfurfural (HMF), which are potentially carcinogenic to humans, are often produced during the hot processing of foods. This study first...
Acrylamide (AA) and 5-hydroxymethylfurfural (HMF), which are potentially carcinogenic to humans, are often produced during the hot processing of foods. This study first used a molecular docking model to simulate the binding behavior of four lactic acid bacteria peptidoglycans (PGNs) to AA/HMF, and the binding rate of LAB-based PGNs to AA/HMF was evaluated in vitro. In silico results show that interaction energy is the driving force responsible for the adsorption of LAB-derived PGNs to AA/HMF. In vitro results showed that the PGN of B1-04 bound the most AA (28.7%) and HMF (48.0%), followed by NCFM, CICC 6079, and CICC 22135. Moreover, an AA/HMF-bound layer on the cell surface of B1-04 was observed via AFM and SEM due to adsorption. XPS analysis indicated the removal rate of AA/HMF by selected strains was positively correlated with the proportion of C-O, C=O, and N-H groups of PGNs. The atoms O1, O2, O3, O4, N1, N2, N3, H1, and H2 are involved in the adsorption of LAB-based PGNs to AA/HMF. Thus, the PGNs derived from these four strains can be regarded as natural adsorbents for the binding of AA/HMF.
PubMed: 38922060
DOI: 10.3390/toxics12060380