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Frontiers in Bioengineering and... 2024In this study, native ureolytic bacteria were isolated from copper tailings soils to perform microbial-induced carbonate precipitation (MICP) tests and evaluate their...
In this study, native ureolytic bacteria were isolated from copper tailings soils to perform microbial-induced carbonate precipitation (MICP) tests and evaluate their potential for biocement formation and their contribution to reduce the dispersion of particulate matter into the environment from tailings containing potentially toxic elements. It was possible to isolate a total of 46 bacteria; among them only three showed ureolytic activity: T130-1, sp. T130-13 and sp. T130-14. Biocement cores were made by mixing tailings with the isolated bacteria in presence of urea, resulting similar to those obtained with and used as positive control. Indeed, XRD analysis conducted on biocement showed the presence of microcline ( 17%; 11. 9%), clinochlore (, 6.9%) and magnesiumhornblende ( sp. 17.8%; 14.6%); all these compounds were not initially present in the tailings soils. Moreover the presence of calcite (control 0.828%; sp. 5.4%) and hematite (control 0.989%; 6.4%) was also significant unlike the untreated control. The development of biofilms containing abundant amount of Ca, C, and O on microscopic soil particles was evidenced by means of FE-SEM-EDX and XRD. Wind tunnel tests were carried out to investigate the resistance of biocement samples, accounted for a mass loss five holds lower than the control, i.e., the rate of wind erosion in the control corresponded to 82 g/mh while for the biocement treated with sp. it corresponded to only 16.371 g/mh. Finally, in compression tests, the biocement samples prepared with (28.578 psi) and sp. (28.404 psi) showed values similar to those obtained with (27.102 psi), but significantly higher if compared to the control (15.427 psi), thus improving the compression resistance capacity of the samples by 85.2% and 84.1% with respect to the control. According to the results obtained, the biocement samples generated with the native strains showed improvements in the mechanical properties of the soil supporting them as potential candidates in applications for the stabilization of mining liabilities in open environments using bioaugmentation strategies with native strains isolated from the same mine tailing.
PubMed: 38938979
DOI: 10.3389/fbioe.2024.1393334 -
BMC Microbiology Jun 2024Bacterial antimicrobial resistance poses a severe threat to humanity, necessitating the urgent development of new antibiotics. Recent advances in genome sequencing offer...
BACKGROUND
Bacterial antimicrobial resistance poses a severe threat to humanity, necessitating the urgent development of new antibiotics. Recent advances in genome sequencing offer new avenues for antibiotic discovery. Paenibacillus genomes encompass a considerable array of antibiotic biosynthetic gene clusters (BGCs), rendering these species as good candidates for genome-driven novel antibiotic exploration. Nevertheless, BGCs within Paenibacillus genomes have not been extensively studied.
RESULTS
We conducted an analysis of 554 Paenibacillus genome sequences, sourced from the National Center for Biotechnology Information database, with a focused investigation involving 89 of these genomes via antiSMASH. Our analysis unearthed a total of 848 BGCs, of which 716 (84.4%) were classified as unknown. From the initial pool of 554 Paenibacillus strains, we selected 26 available in culture collections for an in-depth evaluation. Genomic scrutiny of these selected strains unveiled 255 BGCs, encoding non-ribosomal peptide synthetases, polyketide synthases, and bacteriocins, with 221 (86.7%) classified as unknown. Among these strains, 20 exhibited antimicrobial activity against the gram-positive bacterium Micrococcus luteus, yet only six strains displayed activity against the gram-negative bacterium Escherichia coli. We proceeded to focus on Paenibacillus brasilensis, which featured five new BGCs for further investigation. To facilitate detailed characterization, we constructed a mutant in which a single BGC encoding a novel antibiotic was activated while simultaneously inactivating multiple BGCs using a cytosine base editor (CBE). The novel antibiotic was found to be localized to the cell wall and demonstrated activity against both gram-positive bacteria and fungi. The chemical structure of the new antibiotic was elucidated on the basis of ESIMS, 1D and 2D NMR spectroscopic data. The novel compound, with a molecular weight of 926, was named bracidin.
CONCLUSIONS
This study outcome highlights the potential of Paenibacillus species as valuable sources for novel antibiotics. In addition, CBE-mediated dereplication of antibiotics proved to be a rapid and efficient method for characterizing novel antibiotics from Paenibacillus species, suggesting that it will greatly accelerate the genome-based development of new antibiotics.
Topics: Paenibacillus; Anti-Bacterial Agents; Multigene Family; Genome, Bacterial; Peptide Synthases; Polyketide Synthases; Bacteriocins; Biosynthetic Pathways; Bacterial Proteins; Drug Discovery
PubMed: 38937695
DOI: 10.1186/s12866-024-03375-5 -
Microorganisms May 2024Hot springs worldwide can be a source of extremophilic microorganisms of biotechnological interest. In this study, samplings of a hot spring in Hidalgo, Mexico, were...
Hot springs worldwide can be a source of extremophilic microorganisms of biotechnological interest. In this study, samplings of a hot spring in Hidalgo, Mexico, were conducted to isolate, identify, and characterize morphologically, biochemically, and molecularly those bacterial strains with potential industrial applications. In addition, a physicochemical and geochemical examination of the hot spring was conducted to fully understand the study region and its potential connection to the strains discovered. The hot spring was classified as sulfate-calcic according to the Piper Diagram; the hydrogeochemical analysis showed the possible interactions between minerals and water. Eighteen bacterial strains were isolated with optimal growth temperatures from 50 to 55 °C. All strains are Gram-positive, the majority having a rod shape, and one a round shape, and 17 produce endospores. Hydrolysis tests on cellulose, pectin, and xylan agar plates demonstrated enzymatic activity in some of the strains. Molecular identification through the 16S rDNA gene allowed classification of 17 strains within the Phylum Firmicutes and one within Deinococcus-Thermus. The bacterial strains were associated with the genera , , , , and , indicating a diversity of bacterial strains with potential industrial applications.
PubMed: 38930448
DOI: 10.3390/microorganisms12061066 -
Journal of Basic Microbiology Jun 2024This work aimed to isolate and characterize a novel chitin-degrading bacterium from Yok Don National Park, Vietnam, for crop production studies. Among the chitinolytic...
This work aimed to isolate and characterize a novel chitin-degrading bacterium from Yok Don National Park, Vietnam, for crop production studies. Among the chitinolytic isolates, strain YSY-4.3 was selected, which grew rapidly and produced a large halo around the colony. 16S rDNA analysis indicated that the strain is a novel species in the genus paenibacillus, and an in vitro evaluation showed that the strain produced phytohormones (IAA, GA3, and zeatin), biofilms, and siderophores; possessed cellulase; and exerted antifungal activity. The whole genome of the strain was 5,628,400 bp with 49.3% GC content, 5056 coding sequences, 48 tRNA, and 1 rRNA. It shared the highest values of digital DNA-DNA hybridization (67.4%) and average nucleotide identity (89.54%) with those of Paenibacillus woosongensis B2_4 (CP126084.1), suggesting a novel species. Of the coding sequences, 4287 proteins were identified by COG, and 2561 were assigned by KEGG. The genome contained at least 51 genes involved in plant growth and resistance to heavy-metal toxicity and 359 carbohydrate-active enzymes. The chitinolytic system of the strain was composed of 15 enzymes, among them, PsChiC, which contained a GH18 catalytic domain and a GH5 catalytic domain, had not been previously reported. In addition, the genome possessed 15 gene clusters encoding antimicrobial metabolites, 10 of which are possible novel clusters. This study expands knowledge regarding novel chitinolytic bacteria from Yok Don National Park and provides a valuable gene resource for future studies.
PubMed: 38894514
DOI: 10.1002/jobm.202400119 -
Plants (Basel, Switzerland) May 2024Enhancing the aerobic stability of whole-plant corn silage is essential for producing high-quality silage. Our research assessed the effect of inoculation with or and...
Enhancing the aerobic stability of whole-plant corn silage is essential for producing high-quality silage. Our research assessed the effect of inoculation with or and its modulation of the bacterial and fungal microbial community structure in an aerobic stage of whole-plant corn silage. Following treatment with a distilled sterile water control, , and (2 × 10 cfu/g), whole-plant corn was ensiled for 60 days. Samples were taken on days 0, 3, and 7 of aerobic exposure, and the results showed that inoculation with or improved the aerobic stability of silage when compared to the effect of the control ( < 0.05). Inoculation with attenuated the increase in pH value and the decrease in lactic acid in the aerobic stage ( < 0.05), reducing the filamentous fungal counts. On the other hand, inoculation with or increased the diversity of the fungal communities ( < 0.05), complicating the correlation between bacteria or fungi, reducing the relative abundance of and in bacterial communities, and inhibiting the tendency of to replace in fungal communities, thus delaying the aerobic spoilage process. Due to the prevention of the development of aerobic spoilage microorganisms, the silage injected with or exhibited improved aerobic stability.
PubMed: 38891280
DOI: 10.3390/plants13111471 -
Enzyme and Microbial Technology Jun 2024Lipases play a vital role in various biological processes, from lipid metabolism to industrial applications. However, the ever-evolving challenges and diverse substrates...
Lipases play a vital role in various biological processes, from lipid metabolism to industrial applications. However, the ever-evolving challenges and diverse substrates necessitate the continual exploration of novel high-performance lipases. In this study, we employed an in silico mining approach to search for lipases with potential high sn-1,3 selectivity and catalytic activity. The identified novel lipase, PLL, from Paenibacillus larvae subsp. larvae B-3650 exhibited a specific activity of 111.2 ± 5.5 U/mg towards the substrate p-nitrophenyl palmitate (pNPP) and 6.9 ± 0.8 U/mg towards the substrate olive oil when expressed in Escherichia coli (E. coli). Computational design of cysteine mutations was employed to enhance the catalytic performance of PLL. Superior stability was achieved with the mutant K7C/A386C/H159C/K108C (2M3/2M4), showing an increase in melting temperature (T) by 1.9°C, a 2.05-fold prolonged half-life at 45°C, and no decrease in enzyme activity. Another mutant, K7C/A386C/A174C/A243C (2M1/2M3), showed a 4.9-fold enhancement in specific activity without compromising stability. Molecular dynamics simulations were conducted to explore the mechanisms of these two mutants. Mutant 2M3/2M4 forms putative disulfide bonds in the loop region, connecting the N- and C-termini of PLL, thus enhancing overall structural rigidity without impacting catalytic activity. The cysteines introduced in mutant 2M1/2M3 not only form new intramolecular hydrogen bonds but also alter the polarity and volume of the substrate-binding pocket, facilitating the entry of large substrate pNPP. These results highlight an efficient in silico exploration approach for novel lipases, offering a rapid and efficient method for enhancing catalytic performance through rational protein design.
PubMed: 38889604
DOI: 10.1016/j.enzmictec.2024.110472 -
FEMS Microbiology Ecology Jun 2024Fungi are increasingly recognized to play diverse roles within honey bee hives, acting as pathogens, mutualists, and commensals. Pollen products, essential for hive...
Fungi are increasingly recognized to play diverse roles within honey bee hives, acting as pathogens, mutualists, and commensals. Pollen products, essential for hive nutrition, host significant fungal communities with potential protective and nutritional benefits. In this study, we profile the fungal communities and antifungal properties of three pollen products from healthy and stressed hives: fresh pollen collected by forager bees from local plants; stored pollen packed into the comb inside the hive; and bee bread, which is stored pollen following anaerobic fermentation used for bee and larval nutrition. Using amplicon sequencing, we found significant differences in fungal community composition, with hive health and sample type accounting for 8.8% and 19.3% of variation in beta diversity, respectively. Pollen and bee bread extracts had species-specific antimicrobial activity and inhibited the fungal hive pathogens Ascosphaera apis, Aspergillus flavus, and Aspergillus fumigatus, and the bacterial hive pathogen Paenibacillus larvae. Activity was positively correlated with phenolic and antioxidant content and was diminished in stressed hives. The plant source of pollen determined by amplicon sequencing differed in stressed hives, suggesting altered foraging behaviour. These findings illustrate the complex interplay between honey bees, fungal communities, and hive products, which should be considered in hive management and conservation.
Topics: Bees; Animals; Pollen; Fungi; Stress, Physiological; Paenibacillus larvae; Mycobiome; Ascomycota; Anti-Infective Agents
PubMed: 38886123
DOI: 10.1093/femsec/fiae091 -
International Journal of Food... Jun 2024The Protected Designation of Origin (PDO) indication for foods intends to guarantee the conditions of production and the geographical origin of regional products within...
The Protected Designation of Origin (PDO) indication for foods intends to guarantee the conditions of production and the geographical origin of regional products within the European Union. Honey products are widely consumed due to their health-promoting properties and there is a general interest in tracing their authenticity. In this regard, metagenomics sequencing and machine learning (ML) have been proposed as complementary technologies to improve the traceability methods of foods. Therefore, the aim of this study was to analyze the metagenomic profiles of Spanish honeys from three different PDOs (Granada, Tenerife and Villuercas-Ibores), and compare them with non-PDO honeys using ML models (PLS, RF, LOGITBOOST, and NNET). According to the results obtained, non-PDO honeys and Granada PDO showed higher beta diversity values than Tenerife and Villuercas-Ibores PDOs. ML classification of honey products allowed the identification of different microbial biomarkers of the geographical origin of honeys: Lactobacillus kunkeei, Parasaccharibacter apium and Lactobacillus helsingborgensis for PDO honeys and Paenibacillus larvae, Lactobacillus apinorum and Klebsiella pneumoniae for non-PDO honeys. In addition, potential microbial biomarkers of some honey varieties including L. kunkeei for Albaida and Retama del Teide varieties, and P. apium for Tajinaste variety, were identified. ML models were validated on an independent set of samples leading to high accuracy rates (above 90 %). This work demonstrates the potential of ML to differentiate different types of honey using metagenome-based methods, leading to high performance metrics. In addition, ML models discriminate both the geographical origin and variety of products corresponding to different PDOs and non-PDO products. Results here presented may contribute to develop enhanced traceability and authenticity methods that could be applied to a wide range of foods.
PubMed: 38879955
DOI: 10.1016/j.ijfoodmicro.2024.110789 -
Proceedings of the National Academy of... Jun 2024
PubMed: 38870063
DOI: 10.1073/pnas.2410191121 -
International Journal of Systematic and... Jun 2024A Gram-stain-positive, aerobic bacterium, designated as YPD9-1, was isolated from the gut contents of a spotty belly greenling, , collected near Dokdo island, South...
A Gram-stain-positive, aerobic bacterium, designated as YPD9-1, was isolated from the gut contents of a spotty belly greenling, , collected near Dokdo island, South Korea. The rod-shaped cells were oxidase-positive, and catalase-negative. The major cellular fatty acids were anteiso-C, iso-C, C, iso-C and iso-C. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and two unidentified lipids. The DNA G+C content was 47.6 mol% and the predominant respiratory quinone was menaquinone MK-7. The 16S rRNA gene sequence of YPD9-1 showed low sequence similarities to species of the genus , Gsoil 1138 (97.21 % of sequence similarity), CJ25 (97.12 %) and JJ-42 (96.89 %). The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that YPD9-1 formed a distinct branch among other species of the genus . The digital DNA-DNA hybridisation, average nucleotide identity, and average amino acid identity values between YPD9-1 and the related species were in the ranges of 15.3-16.2 %, 74.1-78.4 %, and 71.1-71.9 %, respectively, which are below the species cutoff values. On the basis of the results of the polyphasic analysis, we conclude that strain YPD9-1 represents a novel species of the genus , for which the name sp. nov. is proposed. The type strain of is YPD9-1 (=KCTC 43424 =LMG 32988).
Topics: RNA, Ribosomal, 16S; Base Composition; Phylogeny; DNA, Bacterial; Republic of Korea; Fatty Acids; Paenibacillus; Bacterial Typing Techniques; Sequence Analysis, DNA; Vitamin K 2; Animals; Nucleic Acid Hybridization; Phospholipids
PubMed: 38869487
DOI: 10.1099/ijsem.0.006419