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Applied and Environmental Microbiology Mar 2023Antimicrobial resistance in bacteria is a threat to both human and animal health. We aimed to understand the impact of domestication and antimicrobial treatment on the...
Antimicrobial resistance in bacteria is a threat to both human and animal health. We aimed to understand the impact of domestication and antimicrobial treatment on the types and numbers of resistant bacteria, antibiotic resistance genes (ARGs), and class 1 integrons (C1I) in the equine gut microbiome. Antibiotic-resistant fecal bacteria were isolated from wild horses, healthy farm horses, and horses undergoing veterinary treatment, and isolates (9,083 colonies) were screened by PCR for C1I; these were found at frequencies of 9.8% (vet horses), 0.31% (farm horses), and 0.05% (wild horses). A collection of 71 unique C1I isolates (17 and 54 ) was subjected to resistance profiling and genome sequencing. Farm horses yielded mostly C1I (, , , , , ), while vet horses primarily yielded C1I (, , , , , , ); the vet isolates had more extensive resistance and stronger P promoters in the C1Is. All integrons in were flanked by copies of IS, except in , where a novel IS family element (IS) was implicated in mobilization. In the , C1Is were predominantly associated with IS and also IS, Tn, Tn, Tn, and a putative formaldehyde-resistance transposon (Tn). Several large C1I-containing plasmid contigs were retrieved; two of these (plasmid types Y and F) also had extensive sets of metal resistance genes, including a novel copper-resistance transposon (Tn). Both veterinary treatment and domestication increase the frequency of C1Is in equine gut microflora, and each of these anthropogenic factors selects for a distinct group of integron-containing bacteria. There is increasing acknowledgment that a "one health" approach is required to tackle the growing problem of antimicrobial resistance. This requires that the issue is examined from not only the perspective of human medicine but also includes consideration of the roles of antimicrobials in veterinary medicine and agriculture and recognizes the importance of other ecological compartments in the dissemination of ARGs and mobile genetic elements such as C1I. We have shown that domestication and veterinary treatment increase the frequency of occurrence of C1Is in the equine gut microflora and that, in healthy farm horses, the C1I are unexpectedly found in , while in horses receiving antimicrobial veterinary treatments, a taxonomic shift occurs, and the more typical integron-containing are found. We identified several new mobile genetic elements (plasmids, insertion sequences [IS], and transposons) on genomic contigs from the integron-containing equine bacteria.
Topics: Horses; Animals; Humans; Domestication; DNA Transposable Elements; Plasmids; Integrons; Bacteria; Anti-Bacterial Agents
PubMed: 36988354
DOI: 10.1128/aem.01590-22 -
Archives of Microbiology Feb 2022Sulfoglycolysis pathways enable the breakdown of the sulfosugar sulfoquinovose and environmental recycling of its carbon and sulfur content. The prototypical...
Sulfoglycolysis pathways enable the breakdown of the sulfosugar sulfoquinovose and environmental recycling of its carbon and sulfur content. The prototypical sulfoglycolytic pathway is a variant of the classical Embden-Meyerhof-Parnas (EMP) pathway that results in formation of 2,3-dihydroxypropanesulfonate and was first described in gram-negative Escherichia coli. We used enrichment cultures to discover new sulfoglycolytic bacteria from Australian soil samples. Two gram-positive Arthrobacter spp. were isolated that produced sulfolactate as the metabolic end-product. Genome sequences identified a modified sulfoglycolytic EMP gene cluster, conserved across a range of other Actinobacteria, that retained the core sulfoglycolysis genes encoding metabolic enzymes but featured the replacement of the gene encoding sulfolactaldehyde (SLA) reductase with SLA dehydrogenase, and the absence of sulfoquinovosidase and sulfoquinovose mutarotase genes. Excretion of sulfolactate by these Arthrobacter spp. is consistent with an aerobic saprophytic lifestyle. This work broadens our knowledge of the sulfo-EMP pathway to include soil bacteria.
Topics: Arthrobacter; Australia; Glycolysis; Multigene Family; Sulfur
PubMed: 35201431
DOI: 10.1007/s00203-022-02803-2 -
Microbiology Resource Announcements Sep 2023We report the draft genome sequences of NQ5, strain NQ4, and strain NQ7 isolated from a laboratory-scale membrane bioreactor, soils from San Antonio, TX, USA and...
We report the draft genome sequences of NQ5, strain NQ4, and strain NQ7 isolated from a laboratory-scale membrane bioreactor, soils from San Antonio, TX, USA and sediments from Galveston Bay, TX, USA, respectively. These bacteria degrade the explosive compound nitroguanidine, which is present in some insensitive munitions.
PubMed: 37477431
DOI: 10.1128/MRA.00467-23 -
Journal of Fungi (Basel, Switzerland) Mar 2022True morels (, ) cultivated in soil are subject to complex influences from soil microbial communities. To explore the characteristics of soil microbial communities on...
True morels (, ) cultivated in soil are subject to complex influences from soil microbial communities. To explore the characteristics of soil microbial communities on morel cultivation, and evaluate whether these microbes are related to morel production, we collected 23 soil samples from four counties in Sichuan and Yunnan Provinces, China. Based on ITS and 16S rDNA amplicon sequencing, the alpha diversity analysis indicated that the biodiversity of morel cultivation soil showed a downward trend compared with the bare soil. The results also showed that there were no significant differences in soil microbial communities between OC (bare soil) and OO (after one-year suspension of sowing). This means that, after about one year of stopping sowing, the component and structure of soil that once cultivated morel would be restored. In co-occurrence networks, some noteworthy bacterial microbes involved in nitrogen fixation and nitrification have been identified in soils with high morel yields, such as , , , , , and . In contrast, in soils with low or no morel yield, some pathogenic fungi accounted for a high proportion, including , , , , , and . This study provided valuable information for the isolation and culturing of some beneficial microbes for morel cultivation in further study and, potentially, to harness the power of the microbiome to improve morel production and health.
PubMed: 35330300
DOI: 10.3390/jof8030299 -
MicrobiologyOpen Jan 2021Snow microorganisms play a significant role in climate change and affecting the snow melting rate in the Arctic and Antarctic regions. While research on algae inhabiting...
Snow microorganisms play a significant role in climate change and affecting the snow melting rate in the Arctic and Antarctic regions. While research on algae inhabiting green and red snow has been performed extensively, bacteria dwelling in this biotope have been studied to a much lesser extent. In this study, we performed 16S rRNA gene amplicon sequencing of two green snow samples collected from the coastal area of the eastern part of Antarctica and conducted genotypic and phenotypic profiling of 45 fast-growing bacteria isolated from these samples. 16S rRNA gene amplicon sequencing of two green snow samples showed that bacteria inhabiting these samples are mostly represented by families Burkholderiaceae (46.31%), Flavobacteriaceae (22.98%), and Pseudomonadaceae (17.66%). Identification of 45 fast-growing bacteria isolated from green snow was performed using 16S rRNA gene sequencing. We demonstrated that they belong to the phyla Actinobacteria and Proteobacteria, and are represented by the genera Arthrobacter, Cryobacterium, Leifsonia, Salinibacterium, Paeniglutamicibacter, Rhodococcus, Polaromonas, Pseudomonas, and Psychrobacter. Nearly all bacterial isolates exhibited various growth temperatures from 4°C to 25°C, and some isolates were characterized by a high level of enzymatic activity. Phenotyping using Fourier transform infrared (FTIR) spectroscopy revealed a possible accumulation of intracellular polymer polyhydroxyalkanoates (PHA) or lipids in some isolates. The bacteria showed different lipids/PHA and protein profiles. It was shown that lipid/PHA and protein spectral regions are the most discriminative for differentiating the isolates.
Topics: Antarctic Regions; Bacteria; Climate Change; DNA, Bacterial; Ecosystem; Fourier Analysis; Genotype; Microbiota; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Snow
PubMed: 33377317
DOI: 10.1002/mbo3.1152 -
AMB Express Jan 2023As an indispensable enzyme for the hydrolysis of dextran, dextranase has been widely used in the fields of food and medicine. It should be noted that the weak...
As an indispensable enzyme for the hydrolysis of dextran, dextranase has been widely used in the fields of food and medicine. It should be noted that the weak thermostability of dextranase has become a restricted factor for industrial applications. This study aims to improve the thermostability of dextranase AoDex in glycoside hydrolase (GH) family 49 that derived from Arthrobacter oxydans KQ11. Some mutants were predicted and constructed based on B-factor analysis, PoPMuSiC and HotMuSiC algorithms, and four mutants exhibited higher heat resistance. Compared with the wild-type, mutant S357P showed the best improved thermostability with a 5.4-fold increase of half-life at 60 °C, and a 2.1-fold increase of half-life at 65 °C. Furthermore, S357V displayed the most obvious increase in enzymatic activity and thermostability simultaneously. Structural modeling analysis indicated that the improved thermostability of mutants might be attributed to the introduction of proline and hydrophobic effects, which generated the rigid optimization of the structural conformation. These results illustrated that it was effective to improve the thermostability of dextranase AoDex by rational design and site-directed mutagenesis. The thermostable mutant of dextranase AoDex has potential application value, and it can also provide references for engineering other thermostable dextranases of the GH49 family.
PubMed: 36656394
DOI: 10.1186/s13568-023-01513-2 -
3 Biotech Jan 2022Gut symbiotic bacteria provide protection and nutrition to the host insect. A high reproductive rate and dispersal ability of the rugose spiralling whitefly help this...
UNLABELLED
Gut symbiotic bacteria provide protection and nutrition to the host insect. A high reproductive rate and dispersal ability of the rugose spiralling whitefly help this polyphagous species to develop and thrive on many horticultural crops. In this study, we isolated the cultivable gut bacteria associated with rugose spiralling whitefly and demonstrated their role in the host insect. We also studied the influence of antibiotics on the rugose spiralling whitefly oviposition. A total of 70 gut bacteria were isolated from the second nymphal stage of rugose spiralling whitefly reared on coconut, banana, and sapota using seven growth media. From the 70 isolates, chitinase, siderophore (51), protease (44), and Glutathione-S-Transferase producers (16) were recorded. The activities of chitinase, siderophore, protease, and Glutathione-S-Transferase in the gut bacterial isolates of rugose spiralling whitefly ranged from 0.07 to 3.96 µmol min mL, 10.01 to 76.93%, 2.10 to 83.40%, and 5.21 to 24.48 nmol min mL μg protein, respectively. The16S rRNA gene sequence analysis revealed that bacterial genera associated with the gut of rugose spiralling whitefly included , , , , , and Based on the susceptibility of the gut bacteria to antibiotics, 11antibiotic treatments were administered to the host plant leaves infested with the nymphal stages. The antibiotics were evaluated for their effect on rugose spiralling whitefly oviposition. Among the antibiotic treatments, carbenicillin (100 µg mL) + ciprofloxacin (5 µg mL) significantly reduced the oviposition (13 eggs spiral) and egg hatchability (61.54%) of rugose spiralling whitefly. Disruption of chitinase, siderophore, protease, and detoxification enzyme producers and elimination of these symbionts through antibiotics altered the host insect physiology and indirectly affected whitefly oviposition. In conclusion, gut bacteria-based management strategies might be used as insecticides for the effective control of whiteflies.
SUPPLEMENTARY INFORMATION
The online version contains supplementary material available at 10.1007/s13205-021-03081-3.
PubMed: 34966637
DOI: 10.1007/s13205-021-03081-3 -
Scientific Reports Aug 2020Although many advances have been achieved to treat aggressive tumours, cancer remains a leading cause of death and a public health problem worldwide. Among the main...
Although many advances have been achieved to treat aggressive tumours, cancer remains a leading cause of death and a public health problem worldwide. Among the main approaches for the discovery of new bioactive agents, the prospect of microbial secondary metabolites represents an effective source for the development of drug leads. In this study, we investigated the actinobacterial diversity associated with an endemic Antarctic species, Deschampsia antarctica, by integrated culture-dependent and culture-independent methods and acknowledged this niche as a reservoir of bioactive strains for the production of antitumour compounds. The 16S rRNA-based analysis showed the predominance of the Actinomycetales order, a well-known group of bioactive metabolite producers belonging to the Actinobacteria phylum. Cultivation techniques were applied, and 72 psychrotolerant Actinobacteria strains belonging to the genera Actinoplanes, Arthrobacter, Kribbella, Mycobacterium, Nocardia, Pilimelia, Pseudarthrobacter, Rhodococcus, Streptacidiphilus, Streptomyces and Tsukamurella were identified. The secondary metabolites were screened, and 17 isolates were identified as promising antitumour compound producers. However, the bio-guided assay showed a pronounced antiproliferative activity for the crude extracts of Streptomyces sp. CMAA 1527 and Streptomyces sp. CMAA 1653. The TGI and LC values revealed the potential of these natural products to control the proliferation of breast (MCF-7), glioblastoma (U251), lung/non-small (NCI-H460) and kidney (786-0) human cancer cell lines. Cinerubin B and actinomycin V were the predominant compounds identified in Streptomyces sp. CMAA 1527 and Streptomyces sp. CMAA 1653, respectively. Our results suggest that the rhizosphere of D. antarctica represents a prominent reservoir of bioactive actinobacteria strains and reveals it as an important environment for potential antitumour agents.
Topics: Actinobacteria; Actinomycetales; Antarctic Regions; Anthracyclines; Antineoplastic Agents; Biological Factors; Cell Line, Tumor; Cell Proliferation; Culture Techniques; Dactinomycin; Drug Discovery; Humans; Neoplasms; Streptomyces
PubMed: 32807803
DOI: 10.1038/s41598-020-69786-2 -
Microbiology Resource Announcements Nov 2022Phages GlobiWarming and TaylorSipht are siphoviruses isolated on Arthrobacter globiformis . GlobiWarming has a 42,691 bp long genome that encodes 74 genes, whereas...
Phages GlobiWarming and TaylorSipht are siphoviruses isolated on Arthrobacter globiformis . GlobiWarming has a 42,691 bp long genome that encodes 74 genes, whereas TaylorSipht has a 39,051 bp genome that encodes 65 genes. Both phages encode functions typical of temperate phages, with each including an immunity repressor, integrase, and excise.
PubMed: 36197292
DOI: 10.1128/mra.00923-22 -
Frontiers in Plant Science 2022A bacterial strain JI39 that had plant growth-promoting traits was isolated from the rhizosphere soil of . It had the ability to produce high indole-3-acetic acid (13.1...
A bacterial strain JI39 that had plant growth-promoting traits was isolated from the rhizosphere soil of . It had the ability to produce high indole-3-acetic acid (13.1 μg/ml), phosphate solubilization (164.2 μg/ml), potassium solubilization (16.1 μg/ml), and nitrogen fixation. The strain JI39 was identified to be based on morphological, physiological, and biochemical traits and through 16S rDNA sequence analysis. The optimal culture environment for strain growth was 1.0% NaCl, 30°C, pH 6.0, and without UV irradiation. The strain can produce cellulase and protease. The strain JI39 can significantly promote the growth of ginseng. After ginseng seeds were treated with 3 × 10 CFU/ml of JI39 bacterial suspension, the shoot's length was significantly increased by 64.61% after 15 days. Meanwhile, the fresh weight of 2-year-old ginseng roots was significantly increased by 24.70% with a treatment by the 10 CFU/ml bacterial suspension after 150 days in the field. The gene expression of phenylalanine ammonia-lyase (PAL), β-1.3 glucanase (β), chitinase (CHI), superoxide dismutase (SOD), and peroxidase (POD) of ginseng was upregulated, and it also can improve the soil urease, phosphatase, invertase, and catalase activity. In conclusion, the bacterial strain JI39 could efficiently promote the growth of ginseng and has the potential to be a good microbial fertilizer for ginseng.
PubMed: 35615118
DOI: 10.3389/fpls.2022.873621