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Biomolecules Aug 2022The Gram-positive and spore-forming bacterium Brevibacillus laterosporus (Bl) belongs to the Brevibacillus brevis phylogenetic cluster. Isolates of the species have...
The Gram-positive and spore-forming bacterium Brevibacillus laterosporus (Bl) belongs to the Brevibacillus brevis phylogenetic cluster. Isolates of the species have demonstrated pesticidal potency against a wide range of invertebrate pests and plant diseases. Two New Zealand isolates, Bl 1821L and Bl 1951, are under development as biopesticides for control of diamondback moth and other pests. However, due to the often-restricted growth of these endemic isolates, production can be an issue. Based on the previous work, it was hypothesised that the putative phages might be involved. During investigations of the cause of the disrupted growth, electron micrographs of crude lysate of Bl 1821L showed the presence of phages’ tail-like structures. A soft agar overlay method with PEG 8000 precipitation was used to differentiate between the antagonistic activity of the putative phage and phage tail-like structures (bacteriocins). Assay tests authenticated the absence of putative phage activity. Using the same method, broad-spectrum antibacterial activity of Bl 1821L lysate against several Gram-positive bacteria was found. SDS-PAGE of sucrose density gradient purified and 10 kD MWCO concentrated lysate showed a prominent protein band of ~48 kD, and transmission electron microscopy revealed the presence of polysheath-like structures. N-terminal sequencing of the ~48 kD protein mapped to a gene with weak predicted amino acid homology to a Bacillus PBSX phage-like element xkdK, the translated product of which shared >90% amino acid similarity to the phage tail-sheath protein of another Bl published genome, LMG15441. Bioinformatic analysis also identified an xkdK homolog in the Bl 1951 genome. However, genome comparison of the region around the xkdK gene between Bl 1821L and Bl 1951 found differences including two glycine rich protein encoding genes which contain imperfect repeats (1700 bp) in Bl 1951, while a putative phage region resides in the analogous Bl 1821L region. Although comparative analysis of the genomic organisation of Bl 1821L and Bl 1951 PBSX-like region with the defective phages PBSX, PBSZ, and PBP 180 of Bacillus subtilis isolates 168 and W23, and Bacillus phage PBP180 revealed low amino acids similarity, the genes encode similar functional proteins in similar arrangements, including phage tail-sheath (XkdK), tail (XkdO), holin (XhlB), and N-acetylmuramoyl-l-alanine (XlyA). AMPA analysis identified a bactericidal stretch of 13 amino acids in the ~48 kD sequenced protein of Bl 1821L. Antagonistic activity of the purified ~48 kD phage tail-like protein in the assays differed remarkably from the crude lysate by causing a decrease of 34.2% in the number of viable cells of Bl 1951, 18 h after treatment as compared to the control. Overall, the identified inducible phage tail-like particle is likely to have implications for the in vitro growth of the insect pathogenic isolate Bl 1821L.
Topics: Amino Acids; Animals; Bacillus; Bacteriocins; Bacteriophages; Brevibacillus; Insecta; Phylogeny
PubMed: 36009048
DOI: 10.3390/biom12081154 -
Microorganisms Jan 2023We have previously reported the draft genome sequences of 59 endospore-forming Gram-positive bacterial strains isolated from Vietnamese crop plants due to their ability...
We have previously reported the draft genome sequences of 59 endospore-forming Gram-positive bacterial strains isolated from Vietnamese crop plants due to their ability to suppress plant pathogens. Based on their draft genome sequence, eleven of them were assigned to the and one to the genus. Further analysis including full genome sequencing revealed that several of these strains represent novel genomospecies. In vitro and in vivo assays demonstrated their ability to promote plant growth, as well as the strong biocontrol potential of directed against phytopathogenic bacteria, fungi, and nematodes. Genome mining identified 157 natural product biosynthesis gene clusters (BGCs), including 36 novel BGCs not present in the MIBiG data bank. Our findings indicate that plant-associated are a rich source of putative antimicrobial compounds and might serve as a valuable starting point for the development of novel biocontrol agents.
PubMed: 36677460
DOI: 10.3390/microorganisms11010168 -
Antibiotics (Basel, Switzerland) Dec 2022Antimicrobial resistance (AMR) is problematic worldwide, and due to the loss of efficiency of many antibiotics, the pressure to discover alternative antimicrobial...
Antimicrobial resistance (AMR) is problematic worldwide, and due to the loss of efficiency of many antibiotics, the pressure to discover alternative antimicrobial molecules has increased. Soil harbors a great biodiversity and biomass of microorganisms, and many antibiotics are produced by soil microbiota. Therefore, soil is a promising reservoir to find new antimicrobial agents. In this respect, novel pedagogical strategies regarding the AMR global crisis have recently been developed in different countries worldwide. Highlighted is the service-learning project "MicroMundo" integrated in a global Citizen Science project called "Tiny Earth". Hence, the present work aimed at determining the antimicrobial activity of soil bacteria, the biodiversity of the selected isolates as putative antimicrobial producers, and their antibiotic resistance profile. Moreover, through the MicroMundo project, we tried to illustrate the relevant link between science and education and the benefits of implementing service-learning methodologies to raise awareness of the AMR problem and to contribute to the search for new alternatives. A total of 16 teachers, 25 university students and 300 secondary school students participated in the search for antimicrobial activity on a collection of 2600 isolates obtained from a total of 130 soil samples analysed. In total, 132 isolates (5% of total tested) were selected as potential antimicrobial producers when two indicator bacteria were used (Escherichia coli and Staphylococcus epidermidis); the most frequent genus among these isolates was Bacillus, followed by Pseudomonas, Paenibacillus and Serratia. The antimicrobial activity (AA) of the 132 potential antimicrobial producers was studied in a second step against 15 indicator bacteria (of six genera and thirteen species, including relevant pathogens). Of the 132 potentially producing bacteria, 32 were selected for further characterization. In this respect, 18 isolates showed low AA, 12 isolates were considered as medium producers, and 2 highly antimicrobial-producing isolates were found (Brevibacillus laterosporus X7262 and Staphylococcus hominis X7276) showing AA against 80% of the 15 indicators tested. Moreover, 48% of the antimicrobial-producing bacteria were susceptible to all antibiotics tested. Due to citizen science, antimicrobial-producing bacteria of great interest have been isolated, managing to raise awareness about the problem of AMR.
PubMed: 36671258
DOI: 10.3390/antibiotics12010057 -
Food Science & Nutrition Jul 2021According to the appearance and technology, traditional fermented Douchi can be divided into dried Douchi and wet Douchi. However, there are few reports on the...
According to the appearance and technology, traditional fermented Douchi can be divided into dried Douchi and wet Douchi. However, there are few reports on the difference of bacterial community structure between them or the influence of bacterial community on product flavor. In this study, high-throughput sequencing technology and electronic nose were used to measure the bacterial diversity and flavor of 40 Douchi samples, and the correlation between them was explored by multivariate statistical means combined with COG database. Results showed that the cumulative average relative abundance of Firmicutes and Proteobacteria in the samples was as high as 95.93%, and the former was the core bacteria phylum. On the whole, the dominant bacteria in Douchi were (50.67%), (14.07%), (2.54%), (1.61%), (1.46%), (1.26%), (1.24%), and (1.19%). LEfSe analysis indicated that can be used as a biomarker in dried fermented soybeans. Meanwhile, dried samples contained more intensive aromatic substances, but were significantly lower in W6S (selectivity to hydrogen) and W3S (methane-aliph) compared with the wet samples. and were helpful to the formation of aromatic flavor in Douchi, but and were the opposite. Gene and microbial phenotypic prediction showed that microorganisms in dried Douchi use protein more efficiently, while in wet Douchi, microbial energy metabolism was more vigorous. The pathogenic potential of microorganisms in dried samples was higher than that in wet. This study can sound the alarm for improving the safety of home-brewed Douchi and provide guidance for the subsequent screening of strains that enhance the flavor of fermented soybeans.
PubMed: 34262706
DOI: 10.1002/fsn3.2280 -
RSC Advances Jun 2022Laccase is regarded as an efficacious eco-friendly enzyme in various industries. Thus, various laccases have been explored to mitigate the environmental effects of...
Laccase is regarded as an efficacious eco-friendly enzyme in various industries. Thus, various laccases have been explored to mitigate the environmental effects of conventional industrial processing; however, the prospects of laccase in hair dyeing have not been thoroughly explored to date. On account of the adverse environmental and health-related issues posed by chemical hair dyeing, laccase as a natural alternative in dyeing hair has recently gained attention. In this study, we executed hair dyeing with different colours and shades of hair dyes developed from natural plant phenols, including ferulic acid, gallic acid, catechol, and syringaldehyde, catalysed by a novel thermostable bacterial laccase (LacT) from . The dyed hair was characterised in terms of its colourimetric parameters (*, *, and *), colour strength (/), reflectance () and colour durability. * means luminosity and is defined by * values from 0 (black) to 100 (white). A positive value of * means red shades and a negative value indicates green shades. A positive value of * shows yellow shades and a negative value indicates blue shades. Optical microscopy of circular and longitudinal sections of the dyed hair revealed that the laccase-catalysed dyes did not merely stick to the surface; instead, they well-penetrated the hair. Furthermore, the dyeing process did not affect the surface morphology of the dyed hair. The dyed hair also exhibited a desirable range of colour diversity in terms of market-driven demands and showed considerable resistance to fading during shampooing and pH alterations. Post-dyeing, the texture and tensile strength of the dyed hair remained nearly unchanged. Overall, the outcomes suggest that LacT holds high potential to be exploited extensively in the hair dyeing industry as an alternative to chemical hair dyes.
PubMed: 35800313
DOI: 10.1039/d2ra02137d -
International Journal of Environmental... Dec 2022Complex bacteria communities that comprised sp. (M1) and sp. (M2) with effective abilities of degrading decabromodiphenyl ether (BDE-209) were investigated for their...
Complex bacteria communities that comprised sp. (M1) and sp. (M2) with effective abilities of degrading decabromodiphenyl ether (BDE-209) were investigated for their degradation characteristics and mechanisms under aerobic conditions. The experimental results indicated that 88.4% of 10 mg L BDE-209 could be degraded after incubation for 120 h under the optimum conditions of pH 7.0, 30 °C and 15% of the inoculation volume, and the addition ratio of two bacterial suspensions was 1:1. Based on the identification of BDE-209 degradation products via liquid chromatography-mass spectrometry (LC-MS) analysis, the biodegradation pathway of BDE-209 was proposed. The debromination, hydroxylation, deprotonation, breakage of ether bonds and ring-opening processes were included in the degradation process. Furthermore, intracellular enzymes had the greatest contribution to BDE-209 biodegradation, and the inhibition of piperyl butoxide (PB) for BDE-209 degradation revealed that the cytochrome P450 (CYP) enzyme was likely the key enzyme during BDE-209 degradation by bacteria M (1+2). Our study provided alternative ideas for the microbial degradation of BDE-209 by aerobic complex bacteria communities in a water system.
Topics: Halogenated Diphenyl Ethers; Biodegradation, Environmental; Bacteria; Hydroxylation
PubMed: 36554891
DOI: 10.3390/ijerph192417012 -
The FEBS Journal Jan 2015The growing emergence of antibiotic-resistant bacteria has led to the exploration of naturally occurring defense peptides as antimicrobials. In this study, we found that...
The growing emergence of antibiotic-resistant bacteria has led to the exploration of naturally occurring defense peptides as antimicrobials. In this study, we found that laterosporulin (LS), a class IId bacteriocin, effectively kills active and nonmultiplying cells of both Gram-positive and Gram-negative bacteria. Fluorescence and electron microscopy suggest that growth inhibition occurs because of increased membrane permeability. The crystal structure of LS at 2.0 Å resolution reveals an all-β conformation of this peptide, with four β-strands forming a twisted β-sheet. All six intrinsic cysteines are intramolecularly disulfide-bonded, with two disulfides constraining the N terminus of the peptide and the third disulfide crosslinking the extreme C terminus, resulting in the formation of a closed structure. The significance of disulfides in maintaining the in-solution peptide structure was confirmed by CD and fluorescence analyses. Despite a low overall sequence similarity, LS has disulfide connectivity [C(I)-C(V), C(II)-C(IV), and C(III)-C(VI)] like that of β-defensins and a striking architectural similarity with α-defensins. Therefore LS presents a missing link between bacteriocins and mammalian defensins, and is also a potential antimicrobial lead, in particular against nonmultiplying bacteria.
Topics: Amino Acid Sequence; Animals; Bacteriocins; Brevibacillus; Cell Membrane Permeability; Crystallography, X-Ray; Cysteine; Defensins; Disulfides; Drug Resistance, Bacterial; Humans; Peptides; Protein Structure, Secondary; Pseudomonas aeruginosa; Staphylococcus aureus
PubMed: 25345978
DOI: 10.1111/febs.13129 -
Applied and Environmental Microbiology Feb 2022Enzymatic degradation of collagen is of great industrial and environmental significance; however, little is known about thermophile-derived collagenolytic proteases....
Maturation Process and Characterization of a Novel Thermostable and Halotolerant Subtilisin-Like Protease with High Collagenolytic Activity but Low Gelatinolytic Activity.
Enzymatic degradation of collagen is of great industrial and environmental significance; however, little is known about thermophile-derived collagenolytic proteases. Here, we report a novel collagenolytic protease (TSS) from thermophilic sp. WF146. The TSS precursor comprises a signal peptide, an N-terminal propeptide, a subtilisin-like catalytic domain, a β-jelly roll (βJR) domain, and a prepeptidase C-terminal (PPC) domain. The maturation of TSS involves a stepwise autoprocessing of the N-terminal propeptide and the PPC domain, and the βJR rather than the PPC domain is necessary for correct folding of the enzyme. Purified mature TSS displayed optimal activity at 70°C and pH 9.0, a half-life of 1.5 h at 75°C, and an increased thermostability as the NaCl concentration increased up to 4 M. TSS possesses an increased number of surface acidic residues and ion pairs, as well as four Ca-binding sites, which contribute to its high thermostability and halotolerance. At high temperatures, TSS exhibited high activity toward insoluble type I collagen and azocoll but showed a low gelatinolytic activity, with a strong preference for Arg and Gly at the P1 and P1' positions, respectively. Both the βJR and PPC domains could bind but not swell collagen, and thus facilitate TSS-mediated collagenolysis via improving the accessibility of the enzyme to the substrate. Additionally, TSS has the ability to efficiently degrade fish scale collagen at high temperatures. Proteolytic degradation of collagen at high temperatures has the advantages of increasing degradation efficiency and minimizing the risk of microbial contamination. Reports on thermostable collagenolytic proteases are limited, and their maturation and catalytic mechanisms remain to be elucidated. Our results demonstrate that the thermophile-derived TSS matures in an autocatalytic manner and represents one of the most thermostable collagenolytic proteases reported so far. At elevated temperatures, TSS prefers hydrolyzing insoluble heat-denatured collagen rather than gelatin, providing new insight into the mechanism of collagen degradation by thermostable collagenolytic proteases. Moreover, TSS has the potential to be used in recycling collagen-rich wastes such as fish scales.
Topics: Amino Acid Sequence; Animals; Catalytic Domain; Endopeptidases; Peptide Hydrolases; Subtilisin
PubMed: 35133860
DOI: 10.1128/aem.02184-21 -
Nature Communications May 2019Many microbial functions happen within communities of interacting species. Explaining how species with disparate growth rates can coexist is important for applications...
Many microbial functions happen within communities of interacting species. Explaining how species with disparate growth rates can coexist is important for applications such as manipulating host-associated microbiota or engineering industrial communities. Here, we ask how microbes interacting through their chemical environment can achieve coexistence in a continuous growth setup (similar to an industrial bioreactor or gut microbiota) where external resources are being supplied. We formulate and experimentally constrain a model in which mediators of interactions (e.g. metabolites or waste-products) are explicitly incorporated. Our model highlights facilitation and self-restraint as interactions that contribute to coexistence, consistent with our intuition. When interactions are strong, we observe that coexistence is determined primarily by the topology of facilitation and inhibition influences not their strengths. Importantly, we show that consumption or degradation of chemical mediators moderates interaction strengths and promotes coexistence. Our results offer insights into how to build or restructure microbial communities of interest.
Topics: Brevibacillus; Escherichia coli; Microbial Interactions; Microbiota; Models, Biological; Staphylococcus
PubMed: 31053707
DOI: 10.1038/s41467-019-10062-x -
PloS One 2019The evolutionary success of insects is arguably due to their ability to build up a complex, highly-adaptable and very effective defense system against numerous...
The evolutionary success of insects is arguably due to their ability to build up a complex, highly-adaptable and very effective defense system against numerous pathogens, including entomopathogenic fungi. This system relies on the humoral immune system and cellular defense reactions. The first line of defense against biological pathogens is a cuticle formed of several layers. The cuticular lipids may contain hydrocarbons, free fatty acids (FFA), alcohols, waxes, glycerides, aldehydes and sterols. Cuticular fatty acids may also play a role in defending against fungal invasion. Our present findings show that the diet of insects can have a significant effect on their sensitivity and defense response to pathogens; for example, while G. mellonella larvae fed on beeswax had a similar appearance to those reared on a semi-artificial diet, they possessed a different cuticular free fatty acid (FFA) profile to those fed on a semi-artificial diet, and were less sensitive to Conidiobolus coronatus infection. It is possible that the presence of heneicosenoic acid (C21:1) and other long-chain free fatty acids (C22:0, C24:0, C26:0), as well as Brevibacillus laterosporus bacteria, on the cuticle of larvae fed on beeswax, plays a protective role against fungal invasion. Insect pests represent a global problem. An understanding of the basic mechanisms underlying the fungal infection of insects might provide a clearer insight into their defenses, thus allowing the design of more effective, and environmentally-friendly, means of controlling them. The greater wax moth is an excellent model for the study of immunology resistance. Knowledge of the influence of diet on pathogen resistance in insects can be also useful for creating a model of human diseases caused by pathogens, such as Candia albicans.
Topics: Animals; Bacterial Infections; Brevibacillus; Conidiobolus; Diet; Fatty Acids; Larva; Lepidoptera; Moths; Waxes; Zygomycosis
PubMed: 30730940
DOI: 10.1371/journal.pone.0211697