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Frontiers in Microbiology 2021Particulate matter (PM) has been a threat to the environment and public health in the metropolises of developing industrial countries such as Beijing. The microorganisms...
Particulate matter (PM) has been a threat to the environment and public health in the metropolises of developing industrial countries such as Beijing. The microorganisms associated with PM have an impact on human health if they are exposed to the respiratory tract persistently. There are few reports on the microbial resources collected from PM and their antimicrobial activities. In this study, we greatly expanded the diversity of available commensal organisms by collecting 1,258 bacterial and 456 fungal isolates from 63 PM samples. A total of 77 bacterial genera and 35 fungal genera were included in our pure cultures, with as the most prevalent cultured bacterial genus, , and as the most prevalent fungal ones. During heavy-haze days, the numbers of colony-forming units (CFUs) and isolates of bacteria and fungi were decreased. , and were found to be enriched during haze days, while , , and were found to be enriched during non-haze days. Antimicrobial activity against common pathogens have been found in 40 bacterial representatives and 1 fungal representative. The collection of airborne strains will provide a basis to greatly increase our understanding of the relationship between bacteria and fungi associated with PM and human health.
PubMed: 35087495
DOI: 10.3389/fmicb.2021.793037 -
International Journal of Molecular... Mar 2023To date, due to the low accessibility of enzymes to xanthan substrates, the enzymolysis of xanthan remains deficient, which hinders the industrial production of...
To date, due to the low accessibility of enzymes to xanthan substrates, the enzymolysis of xanthan remains deficient, which hinders the industrial production of functional oligoxanthan. To enhance the enzymatic affinity against xanthan, the essential role of two carbohydrate binding modules-CBMx and CBM84, respectively, derived from sp. XT11 and sp. 62047-in catalytic properties of endotype xanthanase Xen were investigated for the first time. Basic characterizations and kinetic parameters of different recombinants revealed that, compared with CBMx, CBM84 dramatically increased the thermostability of endotype xanthanase, and endowed the enzyme with higher substrate affinity and catalytic efficiency. Notably, the activity of endotype xanthanase was increased by 16 times after being fused with CBM84. In addition, the presence of both CBMs obviously enabled endotype xanthanase to produce more oligoxanthan, and xanthan digests prepared by Xen-CBM84 showed better antioxidant activity due to the higher content of active oligosaccharides. The results of this work lay a foundation for the rational design of endotype xanthanase and the industrial production of oligoxanthan in the future.
Topics: Polysaccharides, Bacterial; Oligosaccharides
PubMed: 36982553
DOI: 10.3390/ijms24065480 -
Frontiers in Microbiology 2022sp. CTN-16 (GenBank FJ598326) can degrade chlorothalonil (CTN) but not carbendazim (MBC), and sp. MBC-3 (GenBank OK667229) can degrade MBC but not CTN. A functional...
sp. CTN-16 (GenBank FJ598326) can degrade chlorothalonil (CTN) but not carbendazim (MBC), and sp. MBC-3 (GenBank OK667229) can degrade MBC but not CTN. A functional strain BD2 was obtained by protoplast fusion of CTN-16 and MBC-3 to generate a fusant with improved degradation efficiency of CTN and MBC. Fusant-BD2 with eighth transfer on a medium containing CTN and two antibiotics was obtained. To identify and confirm the genetic relationship between parental strains and fusion strain BD2, scanning electron microscopy (SEM), random amplified polymorphic DNA (RAPD), and 16S ribosomal RNA (rRNA) gene sequences analysis were carried out. SEM analysis illustrated BD2 and its parents had some slight differences in the cell morphology. Fusant-BD2 not only possessed the same bands as parental strains but also had its specific bands analyzed through RAPD. The genetic similarity indices for BD2 and its parental strains CTN-16 and MBC-3 are 0.571 and 0.428, respectively. The degradation rates of CTN and MBC were 79.8% and 65.2% in the inorganic salt solution containing 50 mg·L CTN and 50 mg·L MBC, respectively, and the degradation efficiencies were better than the parental strains CTN-16 and MBC-3. This study provides a prospect for the application of fusion strain BD2 in bioremediation of CTN and MBC contaminated sites.
PubMed: 35359711
DOI: 10.3389/fmicb.2022.842736 -
Applied and Environmental Microbiology Nov 2023Polyhydroxyalkanoate (PHA) is a highly biodegradable microbial polyester, even in marine environments. In this study, we incorporated an enrichment culture-like approach...
Polyhydroxyalkanoate (PHA) is a highly biodegradable microbial polyester, even in marine environments. In this study, we incorporated an enrichment culture-like approach in the process of isolating marine PHA-degrading bacteria. The resulting 91 isolates were suggested to fall into five genera (, , , , and ) based on 16S rRNA analysis, including two novel genera ( and ) as marine PHA-degrading bacteria. (DSM 20489) and (NBRC 102226), the type strains closest to the several isolates, have an extracellular poly(3-hydroxybutyrate) [P(3HB)] depolymerase homolog that does not fit a marine-type domain composition. However, exhibited no PHA degradation ability, unlike . This result demonstrates that the isolated spp. are different species from . P(3HB) depolymerase homologs in the genus should be scrutinized in the future, particularly about which ones work as the depolymerase.
Topics: Polyhydroxyalkanoates; RNA, Ribosomal, 16S; Bays; Seawater; Pseudoalteromonas
PubMed: 37855636
DOI: 10.1128/aem.01488-23 -
Frontiers in Microbiology 2021Chronic and repeated exposure of environmental bacterial communities to anthropogenic antibiotics have recently driven some antibiotic-resistant bacteria to acquire...
Chronic and repeated exposure of environmental bacterial communities to anthropogenic antibiotics have recently driven some antibiotic-resistant bacteria to acquire catabolic functions, enabling them to use antibiotics as nutritive sources (antibiotrophy). Antibiotrophy might confer a selective advantage facilitating the implantation and dispersion of antibiotrophs in contaminated environments. A microcosm experiment was conducted to test this hypothesis in an agroecosystem context. The sulfonamide-degrading and resistant bacterium sp. C448 was inoculated in four different soil types with and without added sulfamethazine and/or swine manure. After 1 month of incubation, sp. (and its antibiotrophic gene ) was detected only in the sulfamethazine-treated soils, suggesting a low competitiveness of the strain without antibiotic selection pressure. In the absence of manure and despite the presence of sp. C448, only one of the four sulfamethazine-treated soils exhibited mineralization capacities, which were low (inferior to 5.5 ± 0.3%). By contrast, manure addition significantly enhanced sulfamethazine mineralization in all the soil types (at least double, comprised between 5.6 ± 0.7% and 19.5 ± 1.2%). These results, which confirm that the presence of functional genes does not necessarily ensure functionality, suggest that sulfamethazine does not necessarily confer a selective advantage on the degrading strain as a nutritional source. 16S rDNA sequencing analyses strongly suggest that sulfamethazine released trophic niches by biocidal action. Accordingly, manure-originating bacteria and/or sp. C448 could gain access to low-competition or competition-free ecological niches. However, simultaneous inputs of manure and of the strain could induce competition detrimental for sp. C448, forcing it to use sulfamethazine as a nutritional source. Altogether, these results suggest that the antibiotrophic strain studied can modulate its sulfamethazine-degrading function depending on microbial competition and resource accessibility, to become established in an agricultural soil. Most importantly, this work highlights an increased dispersal potential of antibiotrophs in antibiotic-polluted environments, as antibiotics can not only release existing trophic niches but also form new ones.
PubMed: 33841365
DOI: 10.3389/fmicb.2021.643087 -
Microorganisms Jan 2022The exploration of certain microbial resources such as beneficial endophytic microorganisms is considered a promising strategy for the discovery of new antimicrobial...
The exploration of certain microbial resources such as beneficial endophytic microorganisms is considered a promising strategy for the discovery of new antimicrobial compounds for the pharmaceutical industries and agriculture. Thirty-one endophytic bacterial strains affiliated with , , , , , and were previously isolated from vetiver ( (L.) Roberty) roots. These endophytes showed antifungal activity against and could be a source of antimicrobial metabolites. In this study, in particular, using high-throughput screening, we analyzed their antagonistic activities and those of their cell-free culture supernatants against three species of plant pathogens, a bacterial strain of , and a yeast strain of , as well as their capacity to produce lipopeptides. The results showed that the culture supernatants of four strains close to species exhibited antimicrobial activities against species and . Using mass spectrometry analyses, we identified two groups of lipopeptides (surfactins and plipastatins) in their culture supernatants. Whole-genome sequencing confirmed that these bacteria possess NRPS gene clusters for surfactin and plipastatin. In vitro tests confirmed the inhibitory effect of plipastatin alone or in combination with surfactin against the three species.
PubMed: 35208667
DOI: 10.3390/microorganisms10020209 -
Journal of Oral Microbiology 2017Geographic tongue (GT) is an oral mucosal lesion that affects the tongue. The association between GT and the bacterial colonization profiles of the tongue is not clear....
Geographic tongue (GT) is an oral mucosal lesion that affects the tongue. The association between GT and the bacterial colonization profiles of the tongue is not clear. Lingual swabs were collected from lesion sites and healthy sites of 35 patients with GT (19 males and 16 females; M = 54.3 ± 16.1 years) and 22 controls (12 males and 10 females; M = 56.3 ± 15.8 years). Bacterial DNA was extracted and sequenced by next-generation sequencing. At the phylum level, Fusobacteria were significantly less abundant, while Spirochaetes were significantly more abundant in GT patients compared to controls. At the operational taxonomic units level, multivariate analysis revealed distinct clusters for the three groups based on the lingual microbiota composition. Acinetobacter and Delftia were significantly associated with GT lesion and healthy sites. However, Microbacterium, Leptospira, Methylotenera, and Lactococcus were significantly associated with GT lesion sites. Additionally, Mogibacterium and Simonsiella were significantly associated with GT healthy sites and controls. The changes in the lingual microbiota profiles of patients with GT imply a shift in the lingual bacterial ecology. However, it remains unknown if this shift is a consequence of the lesions or of factors associated with the initiation and progression of the disease.
PubMed: 28839519
DOI: 10.1080/20002297.2017.1355206 -
Bioresource Technology Aug 2019Hardwood lignin is made of up to 75% syringyl-units and the bioconversion of syringate and syringaldehyde is therefore of considerable interest for biological...
Hardwood lignin is made of up to 75% syringyl-units and the bioconversion of syringate and syringaldehyde is therefore of considerable interest for biological valorization of lignin. In the current study, we have isolated a syringate-consuming bacterium identified as Microbacterium sp. RG1 and characterized its growth on several lignin model compounds. Growth was observed on syringate, 3-O-methylgallate, vanillate, 4-hydroxybenzoate, ferulate and p-coumarate. Toxic aromatic aldehydes such as vanillin and syringaldehyde were converted to their respective alcohols/acids which were eventually consumed with a maximum specific uptake rate of 0.02 and 0.1 mmol (g h) respectively. The isolate was further subjected to whole genome sequencing and putative genes related to the metabolism of syringyl-compounds were mapped for the first time in a Gram-positive bacterium. These findings will be of high significance when designing future host microorganisms and bioprocesses for the efficient valorization of pre-treated lignin feedstocks.
Topics: Lignin; Sequence Analysis
PubMed: 30991184
DOI: 10.1016/j.biortech.2019.121327 -
BioMed Research International 2013A total of 2152 Actinobacteria strains were isolated from native Cerrado (Brazilian Savannah) soils located in Passos, Luminárias, and Arcos municipalities (Minas...
A total of 2152 Actinobacteria strains were isolated from native Cerrado (Brazilian Savannah) soils located in Passos, Luminárias, and Arcos municipalities (Minas Gerais State, Brazil). The soils were characterised for chemical and microbiological analysis. The microbial analysis led to the identification of nine genera (Streptomyces, Arthrobacter, Rhodococcus, Amycolatopsis, Microbacterium, Frankia, Leifsonia, Nakamurella, and Kitasatospora) and 92 distinct species in both seasons studied (rainy and dry). The rainy season produced a high microbial population of all the aforementioned genera. The pH values of the soil samples from the Passos, Luminárias, and Arcos regions varied from 4.1 to 5.5. There were no significant differences in the concentrations of phosphorus, magnesium, and organic matter in the soils among the studied areas. Samples from the Arcos area contained large amounts of aluminium in the rainy season and both hydrogen and aluminium in the rainy and dry seasons. The Actinobacteria population seemed to be unaffected by the high levels of aluminium in the soil. Studies are being conducted to produce bioactive compounds from Actinobacteria fermentations on different substrates. The present data suggest that the number and diversity of Actinobacteria spp. in tropical soils represent a vast unexplored resource for the biotechnology of bioactives production.
Topics: Actinobacteria; Brazil; Ecology; Rain; Seasons; Soil; Soil Microbiology
PubMed: 23555089
DOI: 10.1155/2013/503805 -
F1000Research 2021, a green micro-alga, is normally cultured in laboratories in Tris-Acetate Phosphate (TAP), a medium which contains acetate as the sole carbon source. Acetate in TAP can...
, a green micro-alga, is normally cultured in laboratories in Tris-Acetate Phosphate (TAP), a medium which contains acetate as the sole carbon source. Acetate in TAP can lead to occasional bacterial and fungal contamination. We isolated a yellow-pigmented bacterium from a TAP plate. It was named Clip185 based on the strain plate it was isolated from. In this article we present our work on the isolation, taxonomic identification and physiological and biochemical characterizations of Clip185. We measured sensitivities of Clip185 to five antibiotics and performed standard microbiological tests to characterize it. We partially sequenced the 16S rRNA gene of Clip185. We identified the yellow pigment of Clip185 by spectrophotometric analyses. We tested tolerance of Clip185 to six heavy metals by monitoring its growth on Lysogeny Broth (LB) media plates containing 0.5 mM -10 mM concentrations of six different heavy metals. Clip185 is an aerobic, gram-positive rod, oxidase-negative, mesophilic, alpha-hemolytic bacterium. It can ferment glucose, sucrose and mannitol. It is starch hydrolysis-positive. It is very sensitive to vancomycin but resistant to penicillin and other bacterial cell membrane- and protein synthesis-disrupting antibiotics. Clip185 produces a C50 carotenoid, decaprenoxanthin, which is a powerful anti-oxidant with a commercial demand. Decaprenoxanthin production is induced in Clip185 under light. NCBI-BLAST analyses of the partial 16S rRNA gene sequence of Clip185 revealed a 99% sequence identity to that of strain PK1-12M and strain MDP6. Clip185 is able to tolerate toxic concentrations of six heavy metals. Our results show that Clip185 belongs to the genus . In the future, whole genome sequencing of Clip185 will clarify if Clip185 is a new species or a novel strain of , and will reveal its genes involved in antibiotic-resistance, heavy-metal tolerance and regulation of decaprenoxanthin biosynthesis.
Topics: Anti-Bacterial Agents; Bacteria; Chlamydomonas reinhardtii; Metals, Heavy; RNA, Ribosomal, 16S
PubMed: 34540203
DOI: 10.12688/f1000research.53779.2