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Chemical Science Nov 2023Lasso peptides are a class of ribosomally synthesized and post-translationally modified peptides (RiPPs) that feature an isopeptide bond and a distinct lariat fold. A...
Lasso peptides are a class of ribosomally synthesized and post-translationally modified peptides (RiPPs) that feature an isopeptide bond and a distinct lariat fold. A growing number of secondary modifications have been described that further decorate lasso peptide scaffolds. Using genome mining, we have discovered a pair of lasso peptide biosynthetic gene clusters (BGCs) that include cytochrome P450 genes. Using mass spectrometry, stable isotope incorporation, and extensive 2D-NMR spectrometry, we report the structural characterization of two unique examples of (C-N) biaryl-linked lasso peptides. Nocapeptin A, from , is tailored with a Trp-Tyr crosslink, while longipepetin A, from , features a Trp-Trp linkage. Besides the unusual bicyclic frame, a Met of longipepetin A undergoes -methylation to yield a trivalent sulfonium, a heretofore unprecedented RiPP modification. A bioinformatic survey revealed additional lasso peptide BGCs containing P450 enzymes which await future characterization. Lastly, nocapeptin A bioactivity was assessed against a panel of human and bacterial cell lines with modest growth-suppression activity detected towards .
PubMed: 38023510
DOI: 10.1039/d3sc02380j -
Brazilian Journal of Microbiology :... Jun 2024In recent years, some microorganisms have shown resistance to conventional treatments. Considering this increase in resistant pathogens, treatment alternatives are...
In recent years, some microorganisms have shown resistance to conventional treatments. Considering this increase in resistant pathogens, treatment alternatives are needed to promote greater treatment efficiency. In this sense, antimicrobial photodynamic therapy (aPDT) has been an alternative treatment. This technique uses a photosensitizer that is activated by light with a specific wavelength producing reactive species, leading to the death of pathogenic microorganisms. In this study, bacteriochlorophyll derivatives such as bacteriochlorin metoxi (Bchl-M) and bacteriochlorin trizma (Bchl-T) obtained from purple bacterium (Rhodopseudomonas faecalis), were evaluated as photosensitizers in the aPDT. Photodynamic inactivation (PDI) of the microorganisms Staphylococcus aureus, Micrococcus luteus, Candida albicans and Pseudomonas aeruginosa was investigated with both bacteriochlorins (Bchl-M and Bchl-T) at different concentrations (1, 15 and 30 µM for S. aureus; 1, 15, 30, 45, 60 and 75 µM for M. luteus; 30, 60, 90, 105, 120 and 150 µM for C. albicans; and 200 µM for P. aeruginosa) and different doses of light (20 and 30 J/cm for S. aureus and M. luteus; 30 and 45 J/cm for C. albicans; and 45 J/cm for P. aeruginosa) to inactivate them. Both photosensitizers showed good activation against S. aureus and for M. luteus, we observed the inactivation of these microorganisms at approximately 3 log, showing to be a good photosensitizers for these microorganisms.
Topics: Photosensitizing Agents; Candida albicans; Pseudomonas aeruginosa; Staphylococcus aureus; Light; Photochemotherapy; Porphyrins; Microbial Viability; Micrococcus luteus; Bacteria
PubMed: 38378880
DOI: 10.1007/s42770-024-01278-1 -
Access Microbiology 2023Dormant bacterial cells do not divide and are not immediately culturable, but they persist in a state of low metabolic activity, a physiological state having clinical...
Dormant bacterial cells do not divide and are not immediately culturable, but they persist in a state of low metabolic activity, a physiological state having clinical relevance, for instance in latent tuberculosis. Resuscitation-promoting factors (Rpfs) are proteins that act as signalling molecules mediating growth and replication. In this study we aimed to test the effect of Rpfs from on the number and diversity of cultured bacteria using insect and soil samples, and to examine if the increase in culturability could be reproduced with the putative reaction product of Rpf, 1,6-anhydro--acetylmuramic acid (1,6-anhydro-MurNAc). The gene from was amplified and cloned into a pET21b expression vector and the protein was expressed in BL21(DE3) cells and purified by affinity chromatography using a hexa-histidine tag. 1,6-Anhydro-MurNAc was prepared using reported chemical synthesis methods. Recombinant Rpf protein or 1,6-anhydro-MurNAc were added to R2A cultivation media, and their effect on the culturability of bacteria from eight environmental samples including four cockroach guts and four soils was examined. Colony-forming units, 16S rRNA gene copies and Illumina amplicon sequencing of the 16S rRNA gene were measured for all eight samples subjected to three different treatments: Rpf, 1,6-anhydro-MurNAc or blank control. Both Rpf and 1,6-anhydro-MurNAc increased the number of colony-forming units and of 16S rRNA gene copies across the samples although the protein was more effective. The Rpf and 1,6-anhydro-MurNAc promoted the cultivation of a diverse set of bacteria and in particular certain clades of the phyla and . This study opens the path for improved cultivation strategies aiming to isolate and study yet undescribed living bacterial organisms.
PubMed: 37841103
DOI: 10.1099/acmi.0.000647.v4 -
Pharmaceuticals (Basel, Switzerland) Oct 2023The aim of this work was to provide an overview of available information on the antibacterial and antifungal properties of extracts. A literature search of Scopus,... (Review)
Review
The aim of this work was to provide an overview of available information on the antibacterial and antifungal properties of extracts. A literature search of Scopus, PubMed/Medline, and Google Scholar for peer-reviewed articles published between January 2000 and June 2023 was undertaken. A total of 23 studies were eligible for inclusion in this review. Significant variation of antimicrobial activity depending on the tested species and strains, type of extract solvent, or plant organs utilized for the extract preparation was found. extracts were active against both Gram-positive and Gram-negative bacteria and showed antimycotic effects against the fungi of and and the dermatophytes spp. Greater susceptibility of Gram-positive than Gram-negative bacteria to fireweed extracts was found. A strong antibacterial effect was recorded for , , , , , , and including multi-drug resistant strains. extract might find practical application as an antimicrobial in wound healing, components of cosmetic products for human and animals, or as food preservatives.
PubMed: 37895890
DOI: 10.3390/ph16101419 -
Frontiers in Pediatrics 2023To explore the clinical characteristics of bloodstream infection in an infant and characterize the phenotype and genotype of the isolated strains, as well as seek...
PURPOSE
To explore the clinical characteristics of bloodstream infection in an infant and characterize the phenotype and genotype of the isolated strains, as well as seek suitable infection models for assessing virulence.
METHODS
Clinical data was collected from an infant patient diagnosed with bloodstream infection. Metagenomic sequencing was performed on the isolated blood sample. The strain was isolated and underwent mass spectrometry, biochemical tests, antibiotic susceptibility assays, and whole-genome sequencing. The infection model was used to assess virulence.
RESULTS
Patient responded poorly to cephalosporins, but recovered after Linezolid treatment. Metagenomic sequencing identified as the predominant species in the sample, confirming infection. They were identified as with a high confidence level of 98.99% using mass spectrometry. The strain showed positive results for Catalase, Oxidase, and Urea tests, and negative results for Mannose, Xylose, Lactose, Mannitol, Arginine, and Galactose tests, consistent with the biochemical profile of reference standards. susceptibility to 15 antibiotics was demonstrated and no resistance genes were detected. Predicted virulence genes, including , were associated with metabolic pathways and the type VI secretion system. The infection model demonstrated dose-dependent survival rates.
CONCLUSION
The infant likely developed a bloodstream infection with due to compromised immunity. Although the isolated strain is sensitive to cephalosporin antibiotics and has low pathogenicity in infection models, clinical treatment with cephalosporins was ineffective. Linezolid proved to be effective, providing valuable guidance for future clinical management of such rare infections.
PubMed: 38188910
DOI: 10.3389/fped.2023.1303040 -
Applied Microbiology and Biotechnology Dec 2024The myxobacteria are an attractive bioresource for bioactive compounds since the large size genome contains many biosynthetic gene clusters of secondary metabolites. The...
The myxobacteria are an attractive bioresource for bioactive compounds since the large size genome contains many biosynthetic gene clusters of secondary metabolites. The genome of the myxobacterium Melittangium boletus contains three biosynthetic gene clusters for lanthipeptide production. One of the gene clusters includes genes coding lanthipeptide precursor (melA), class II lanthipeptide synthetase (melM), and transporter (melT). The amino acid sequence of melA indicated similarity with that of known lanthipeptides mersacidin and lichenicidin A1 by the alignment. To perform heterologous production of new lanthipeptides, the expression vector containing the essential genes (melA and melM) was constructed by utilizing codon-optimized synthetic genes. The co-expression of two genes in the host bacterial cells of Escherichia coli BL21 (DE3) afforded new lanthipeptides named melittapeptins A-C. The structures of melittapeptins A-C including lanthionine/methyllanthionine bridge pattern were proposed based on protease digestion and MS/MS experiments. The native strain of M. boletus did not produce melittapeptins A-C, so heterologous production using the biosynthetic gene cluster was effective in obtaining the lanthipeptides. Melittapeptins A-C showed specific and potent antibacterial activity to the Gram-positive bacterium Micrococcus luteus. To the best of our knowledge, this is the first report of antibacterial lanthipeptides derived from myxobacterial origin. KEY POINTS: • New lanthipeptides melittapeptins were heterologously produced in Escherichia coli. • Melittapeptins showed specific antibacterial activity against Micrococcus luteus. • Melittapeptins were the first antibacterial lanthipeptides of myxobacterial origin.
Topics: Tandem Mass Spectrometry; Bacteriocins; Amino Acid Sequence; Anti-Bacterial Agents; Myxococcales; Escherichia coli
PubMed: 38229328
DOI: 10.1007/s00253-023-12834-4 -
Saudi Journal of Biological Sciences Sep 2023, also known as , is a bacterium that inhabits mucous membranes, human skin, and various environmental sources. It is commonly linked to infections, especially among...
, also known as , is a bacterium that inhabits mucous membranes, human skin, and various environmental sources. It is commonly linked to infections, especially among individuals who have compromised immune systems. is capable of synthesizing the enzyme superoxide dismutase (SOD) as a component of its protective response to reactive oxygen species (ROS). This enzyme serves as a promising target for drug development in various diseases. The current study utilized a subtractive genomics approach to identify potential therapeutic targets from . Additionally, genome mining was employed to identify and characterize the biosynthetic gene clusters (BGCs) responsible for the production of secondary metabolites in (), a bacterium known for its production of therapeutically relevant secondary metabolites. Subtractive genomics resulted in identification of important extracellular protein SOD as a drug target that plays a crucial role in shielding cells from damage caused by ROS. Genome mining resulted in identification of five potential ligands (secondary metabolites) from such as, Bacillibactin (BAC), Paenibactin (PAE), Fengycin (FEN), Surfactin (SUR) and Lichenysin (LIC). Molecular docking was used to predict and analyze the binding interactions between these five ligands and target protein SOD. The resulting protein-ligand complexes were further analyzed for their motions and interactions of atoms and molecules over 250 ns using molecular dynamics (MD) simulation analysis. The analysis of MD simulations suggests, Bacillibactin as the probable candidate to arrest the activities of SOD. All the five compounds reported in this study were found to act by directly/indirectly interacting with ROS molecules, such as superoxide radicals (O-) and hydrogen peroxide (HO), and transforming them into less reactive species. This antioxidant activity contributes to its protective effects against oxidative stress-induced damage in cells making them likely candidate for various applications, including in the development of antioxidant-based therapies, nutraceuticals, and functional foods.
PubMed: 37583871
DOI: 10.1016/j.sjbs.2023.103753 -
Microorganisms Aug 2023In the current study, extensive Orbitrap mass spectrometry analysis was conducted for skin strain C01 planktonic cultures and biofilms after 24 h and 72 h of incubation...
Epinephrine Affects Ribosomes, Cell Division, and Catabolic Processes in Skin Strain C01: Revelation of the Conditionally Extensive Hormone Effect Using Orbitrap Mass Spectrometry and Proteomic Analysis.
In the current study, extensive Orbitrap mass spectrometry analysis was conducted for skin strain C01 planktonic cultures and biofilms after 24 h and 72 h of incubation either in the presence of epinephrine or without any implementations. The investigation revealed the complex and conditionally extensive effect of epinephrine at concentrations closer to normal blood plasma concentrations on both planktonic cultures and biofilms of skin strain C01. The concentrations of hundreds of proteins changed during the shift from planktonic growth mode to biofilm and hundreds of proteins were downregulated or upregulated in the presence of epinephrine. Ribosomal, TCA, and cell division proteins appear to be the most altered in their amounts in the presence of the hormone. Potentially, the regulatory mechanism of this process is connected with c-di-GMP and histidine kinases, which were affected by epinephrine in different samples. The phenomenon of epinephrine-based biofilm regulation in C01 has wide implications for microbial endocrinology and other research areas.
PubMed: 37764026
DOI: 10.3390/microorganisms11092181 -
Archives of Microbiology Dec 2023Due to their non-toxic and non-carcinogenic nature, biopigments have a phenomenal benefit over synthetic pigments, making them a desirable source for human utilization...
Due to their non-toxic and non-carcinogenic nature, biopigments have a phenomenal benefit over synthetic pigments, making them a desirable source for human utilization and a potential alternative to traditional synthetic pigments that are hazardous to the environment and public health. Endosymbiotic interactions between mangrove plants and bacteria could provide an alternate source for the synthesis of unique compounds with potent biomedical applications. Pigmented endophytic bacteria were screened from the explants of Avicennia marina, a mangrove plant, and identified as Micrococcus luteus by molecular characterization. The intracellular pigment was successfully extracted using the sonication-assisted solvent extraction method, and screening factors impacting the pigmentation bioprocess were determined using a one-factor-at-a-time approach. The endophyte produced yellow pigment in the liquid medium, with the maximum growth and pigment production recorded in nutrient broth at 37 ℃ and pH 7 after 96 h of incubation, while the maximum accumulation of pigment was observed in the media supplemented with glucose and tryptone as carbon and nitrogen sources, respectively. The extracted crude pigment was further characterized by ultraviolet, followed by Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry. The obtained crude pigment has been evaluated for its antioxidant and anticancer activity by various assays, such as DPPH radical scavenging activity, FRAP assay, superoxide anion and nitric oxide radical scavenging, metal chelating activity, phosphomolybdenum assay, and MTT assay, respectively, at varying concentrations. The results of our study revealed that the yellow pigment produced by the endophyte showed significant dose-dependent antioxidant and anticancer activity.
Topics: Humans; Antioxidants; Avicennia; Micrococcus luteus; Nutrients; Carbon; Endophytes
PubMed: 38108901
DOI: 10.1007/s00203-023-03751-1 -
Journal, Genetic Engineering &... Dec 2023Lipases have emerged as essential biocatalysts, having the ability to contribute to a wide range of industrial applications. Microbial lipases have garnered significant...
BACKGROUND
Lipases have emerged as essential biocatalysts, having the ability to contribute to a wide range of industrial applications. Microbial lipases have garnered significant industrial attention due to their stability, selectivity, and broad substrate specificity. In the previous study, a unique lipolytic bacterium (Micrococcus luteus EMP48-D) was isolated from tempeh. It turns out the bacteria produce an acidic lipase, which is important in biodiesel production. Our main objectives were to clone the acidic lipase and investigate its potential in biodiesel production.
RESULT
In this study, the gene encoding a lipase from M. luteus EMP48-D was cloned and expressed heterologously in Escherichia coli. To our knowledge, this is the first attempt at the cloning and expression of the lipase gene from Micrococcus luteus. The amino acid sequence was deduced from the nucleotide sequence (1356 bp) corresponded to a protein of 451 amino acid residues with a molecular weight of about 40 kDa. The presence of a signal peptide suggested that the protein was extracellular. A sequence analysis revealed that the protein had a lipase-specific Gly-X-Ser-X-Gly motif. The enzyme was identified as an acidic lipase with a pH preference of 5.0. Fatty acid preferences for enzyme activities were C8 and C12 (p-nitrophenyl esters), with optimum temperatures at 30-40 °C and still remaining active at 80°C. The enzyme was also shown to convert up to 70% of the substrate into fatty acid methyl ester.
CONCLUSION
The enzyme was a novel acidic lipase that demonstrated both hydrolytic and transesterification reactions. It appeared particularly promising for the synthesis of biodiesel as this enzyme's catalytic reaction was optimum at low temperatures and was still active at high temperatures.
PubMed: 38038870
DOI: 10.1186/s43141-023-00611-9