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1.
Chemosphere ; 288(Pt 1): 132475, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34624339

RESUMO

Hydroxylamine, an intermediate product in the nitrification process, is widely found in nature. However, hydroxylamine accumulation can decrease the biological nitrogen removal efficiency by reducing the activities, inhibiting the reproductions, and even causing the death of microorganisms. In this study, a novel heterotrophic nitrification bacterium was separated from biogas digester and identified as Glutamicibacter arilaitensis EM-H8. Strain EM-H8 exhibited efficient hydroxylamine removal (93.75%). The optimal conditions for hydroxylamine removal were as follows: Carbon source, glucose; C/N ratio, 25; temperature, 20 °C; inoculum size, 0.53 × 108 CFU; and shaking speed, 150 rpm. The nitrogen balance results using strain EM-H8 showed that about 26.86% of the initial nitrogen was removed as nitrogenous gas, while 4.6% was converted into biomass under aerobic conditions, confirming that strain EM-H8 possessed the capacity for heterotrophic nitrification. Furthermore, the successful expression of hydroxylamine oxidase (0.065 U/mg protein) showed that strain EM-H8 had the ability to transform hydroxylamine from wastewater.


Assuntos
Desnitrificação , Nitrificação , Aerobiose , Processos Heterotróficos , Hidroxilamina , Hidroxilaminas , Micrococcaceae , Nitritos , Nitrogênio
2.
Arch Microbiol ; 203(10): 6287-6293, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34609528

RESUMO

A Gram-staining-positive actinobacteria strain, designated MY13T, was isolated from deep-sea sediment of the western Pacific Ocean and subjected to a taxonomic polyphasic investigation. Based on the results, cells were aerobic, irregular short rod, non-motile and non-spore-forming. Colonies were cream, circular, smooth, convex, opaque and 1.0-2.0 mm in diameter after growth on MZ2 medium at 40 °C for 72 h. Strain MY13T grew at 4-50 °C (optimum, 40 °C), pH 7-12 (pH 9) and 0.5-15% (w/v) NaCl (3.5%). The 16S rRNA gene sequence analysis revealed that strain MY13T is affiliated with the genus Nesterenkonia and closely related to Nesterenkonia populi GP10-3T (96.6%). Digital DNA-DNA hybridization (dDDH) values and average nucleotide identity (ANI) differentiated it from its closest relatives, with values ranging from 19.8% to 22.4% and 72.6% to 78.0%, respectively. Chemotaxonomic analysis showed that the major menaquinone of strain MY13T was MK-7; major cellular fatty acids were anteiso-C17:0, anteiso-C15:0 and iso-C16:0; whole-cell sugars were galactose and xylose; the peptidoglycan type was L-Lys-Gly-D-Asp; and polar lipids were diphosphatidylglycerol, phosphatidylglycerol, two unknown glycolipids, one unknown polar lipid and two unknown lipids. The G+C content of genomic DNA was 63.1 mol%. Based on the physiological, chemotaxonomic and phylogenetic data, strain MY13T is a novel species of the genus Nesterenkonia, for which the name Nesterenkonia sedimenti sp. nov. is proposed. The type strain is MY13T (= LMG 28111T = MCCC 1A09979T = JCM 19767T = CGMCC 1.12784T).


Assuntos
Ácidos Graxos , Sedimentos Geológicos , Técnicas de Tipagem Bacteriana , DNA Bacteriano/genética , Ácidos Graxos/análise , Micrococcaceae , Fosfolipídeos/análise , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2
3.
Front Public Health ; 9: 697917, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34604154

RESUMO

Disinfection is a key element in controlling infections. Fogging, also known as fumigation, is one of the most effective chemical disinfection methods. Peracetic acid (PAA) is a powerful oxidant with bactericidal and fungicidal properties. The aim of this study is to determine the type of bacteria and fungi present in educational institutions and whether disinfection by PAA fumigation in these institutions is also effective and useful, as demonstrated previously in healthcare centers. This study was carried out in five kindergartens and five primary schools in Bialystok, Poland. Three rooms have been selected in each of these educational institutions, and the disinfection was carried out in 30 rooms in total. Fogging with PAA was performed in selected rooms. Before and after disinfection, samples were collected from four surfaces: walls, tables, doors, and chair backs. Most frequently detected microorganisms in schools and kindergartens were Micrococcus luteus (M. luteus), Staphylococcus warneri (S. warneri), Paracoccus yeei (P. yeei), Staphylococcus hominis ssp. hominis (S. hominis), Kocuria rhizophila (K. rhizophila), Kocuria rosea (K. rosea). In addition, Staphylococcus haemolyticus (S. haemolyticus), Acinetobacter lwoffii (A. lwoffii), Kocuria kristinae (K. kristinae), Lactococcus lactis ssp. lactis (L. lactis) were the most prevalent in kindergartens, whereas Kytococcus sedentarius (K. sedentarius) was the most prevalent in schools. Comparison of the bacterial flora of schools and kindergartens showed statistically significant differences in the prevalence of bacteria on different surfaces. A significant decrease in the number of colonies after disinfection was observed on all surfaces (p < 0.05). In addition, the calculated effectiveness of disinfection was 99.7% in kindergartens and 99.3% in schools. The results indicate that fogging of PAA is a highly effective method of surface disinfection in kindergartens and schools.


Assuntos
Ácido Peracético , Instituições Acadêmicas , Acinetobacter , Actinobacteria , Micrococcaceae , Paracoccus , Ácido Peracético/farmacologia , Staphylococcus
4.
Curr Microbiol ; 78(12): 4084-4097, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34687349

RESUMO

Seagrass meadows constitute a prestigious ecosystem in the marine environment, providing valuable ecological and commercial services. Among the various causes, pollutions are considered one of the significant reasons for seagrass decline globally. This study investigates the impacts of polycyclic aromatic hydrocarbons mixture (pyrene, phenanthrene, and fluorene) on bacterial communities in Halophila ovalis sediments. The seagrass sediment bacterial microbiome was evaluated in a batch culture experiment by Illumina MiSeq sequencing. Culture-able bacterial strains were isolated and characterized by 16S rRNA gene sequencing. The results demonstrated an excellent alpha diversity in the original sediments with a Shannon index of (8.078) compared to the subsequent control group (5.908) and PAH-treated group (PAH-T) (4.916). Three phyla, Proteobacteria, Firmicutes, and Bacteroidetes, were detected in high abundance in the control and PAH-T groups. However, a significant difference (P < 0.05) was observed at the genus level between control and PAH-T group bacterial consortia. Pseudomonas, Mycobacterium, Idiomarina, Hydrogenophaga, Alteromonas, Sphingobacterium, and several others were highly abundant in PAH-T groups. Most of the culture-able isolates recovered in this study showed the closest resemblance to previously identified hydrocarbon-degrading bacteria. Among the three strains, Mix-16 (Citricoccus yambaruensis) and Mix-20 (Gordonia rubripertincta) showed a higher degradation of PAHs than Mix-19 (Isoptericola halotolerans) in the monoculture experiment. The most increased degradation of PAHs was recorded in the co-culture experiment. The present work revealed that PAHs could act as environmental stress and can influence bacterial community succession. Moreover, the co-culture strategy significantly enhanced the biodegradation of PAHs.


Assuntos
Microbiota , Hidrocarbonetos Policíclicos Aromáticos , Actinobacteria , Bactérias/genética , Biodegradação Ambiental , Sedimentos Geológicos , Micrococcaceae , RNA Ribossômico 16S/genética
5.
Int J Mol Sci ; 22(17)2021 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-34502555

RESUMO

The current study aims at the functional and kinetic characterization of protocatechuate (PCA) 4,5-dioxygenase (PcaA) from Pseudarthrobacter phenanthrenivorans Sphe3. This is the first single subunit Type II dioxygenase characterized in Actinobacteria. RT-PCR analysis demonstrated that pcaA and the adjacent putative genes implicated in the PCA meta-cleavage pathway comprise a single transcriptional unit. The recombinant PcaA is highly specific for PCA and exhibits Michaelis-Menten kinetics with Km and Vmax values of 21 ± 1.6 µM and 44.8 ± 4.0 U × mg-1, respectively, in pH 9.5 and at 20 °C. PcaA also converted gallate from a broad range of substrates tested. The enzymatic reaction products were identified and characterized, for the first time, through in situ biotransformation monitoring inside an NMR tube. The PCA reaction product demonstrated a keto-enol tautomerization, whereas the gallate reaction product was present only in the keto form. Moreover, the transcriptional levels of pcaA and pcaR (gene encoding a LysR-type regulator of the pathway) were also determined, showing an induction when cells were grown on PCA and phenanthrene. Studying key enzymes in biodegradation pathways is significant for bioremediation and for efficient biocatalysts development.


Assuntos
Proteínas de Bactérias/genética , Dioxigenases/genética , Regulação Bacteriana da Expressão Gênica , Regulação Enzimológica da Expressão Gênica , Micrococcaceae/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Proteínas de Bactérias/classificação , Proteínas de Bactérias/metabolismo , Biocatálise , Dioxigenases/química , Dioxigenases/metabolismo , Ácido Gálico/química , Ácido Gálico/metabolismo , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Ressonância Magnética/métodos , Micrococcaceae/enzimologia , Estrutura Molecular , Fenantrenos/química , Fenantrenos/metabolismo , Filogenia , Estereoisomerismo , Especificidade por Substrato
6.
J Endod ; 47(12): 1883-1889, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34534554

RESUMO

INTRODUCTION: This study evaluated the relative abundance and ribosomal activity of selected bacteria in carious dentin of teeth with different pulp conditions. METHODS: Thirty healthy patients with class I occlusal caries in molars were categorized into 3 groups based on the pulp diagnosis: normal pulp (NP, n = 10) with caries extending less than half the thickness of dentin (as assessed radiographically), reversible pulpitis (n = 10), and symptomatic irreversible pulpitis (n = 10) with caries extending more than two thirds of the thickness of dentin. Carious dentin samples were collected from the deepest part of the cavity and stored in RNAlater solution (Ambion Inc, Austin, TX). Eight bacterial taxa were evaluated from the samples: Streptococcus mutans, Lactobacillus fermentum, Veillonella, Actinomyces, Rothia dentocariosa, Olsenella profusa, Prevotella intermedia, and Bifidobacterium dentium. The 16S ribosomal RNA (rRNA) gene and 16S rRNA were quantified by real-time polymerase chain reaction and used to calculate the relative genome abundance and relative ribosomal abundance. The Fisher exact test was used to compare proportions between groups. The mean rank difference between the various groups was assessed using the Kruskal-Wallis test with the Bonferroni-Holm correction. RESULTS: The reversible pulpitis group had significantly higher 16S rRNA gene and rRNA counts of Actinomyces (P < .001 and P = .002) and B. dentium (P = .005 and P = .007) relative to the NP group. The symptomatic irreversible pulpitis group had significantly higher 16S rRNA gene and rRNA counts of L. fermentum (P < .001 and P < .001), Actinomyces (P < .001 and P < .001), O. profusa (P < .001 and P < .001), P. intermedia (P = .001 and P = .002), and Bifidobacterium (P < .001 and P < .001) relative to the NP group. CONCLUSIONS: Specific bacterial activity varies in carious dentin of teeth with different pulp conditions.


Assuntos
Cárie Dentária , Actinobacteria , Bifidobacterium , Dentina , Humanos , Micrococcaceae , Dente Molar/diagnóstico por imagem , RNA Ribossômico 16S/genética , Streptococcus mutans
7.
Water Res ; 204: 117593, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34482094

RESUMO

Reconditioning of food processing water streams for reuse is an increasingly common water management practice in the food industry and UV disinfection is often employed as part of the water treatment. Several factors may impact the effect of UV radiation. Here, we aim to assess the impact of cell aggregation on UV inactivation kinetics and investigate if UV exposure induces aggregation. Three strains, isolated from food processing water reuse lines (Raoultella ornithinolytica, Pseudomonas brenneri, Rothia mucilaginosa) and both an aggregating and a non-aggregating strain of Staphylococcus aureus were exposed to UVC light at 255 nm using UV LED equipment. Total Viable Count and phase-contrast microscopy, coupled with image analysis, were used to compare the UV inactivation kinetics with the average particle size for a range of UV doses. Tailing effect, seen as a strong reduction in inactivation rate, was observed for all strains at higher UV doses (industrial strains ≥ 50 or 120 mJ/cm2, S. aureus strains  ≥ 40 or 60 mJ/cm2). The naturally aggregating strains were more UV tolerant, both within and between species. When aggregates of S. aureus were broken, UV tolerance decreased. For the processing water isolates, the lowest applied UV dose (25 mJ/cm2) significantly increased the average particle size. Application of higher UV doses obtained with longer exposure times did not further increase the particle size compared with untreated samples. For the S. aureus strains, however, no consistent change in average particle size was observed due to UV. Our results demonstrate that aggregating strains have a higher degree of protection and that UV radiation induces aggregation in some, but not all bacteria. A better understanding of the mechanisms governing microbial aggregation and survival during UV treatment could help to improve UV applications and predictions of microbial inactivation.


Assuntos
Staphylococcus aureus , Raios Ultravioleta , Bactérias , Desinfecção , Enterobacteriaceae , Cinética , Micrococcaceae , Pseudomonas
8.
Front Cell Infect Microbiol ; 11: 691092, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34490138

RESUMO

Oral microbiota is constantly changing with the host state, whereas the oral microbiome of chronic erythematous candidiasis remains poorly understood. The aim of this study was to compare oral microbial signatures and functional profiling between chronic erythematous candidiasis and healthy subjects. Using shotgun metagenomic sequencing, we analyzed the microbiome in 12 chronic erythematous candidiasis, 12 healthy subjects, and 2 chronic erythematous candidiasis cured by antifungal therapy. We found that the salivary microbiota of chronic erythematous candidiasis was significantly different from that of healthy subjects. Among them, Rothia mucilaginosa and Streptococcus mitis were the most abundant disease-enriched species (Mann-Whitney U-test, P < 0.05). In addition, co-occurrence network analysis showed that C. albicans formed densely connected modules with oral bacterial species and was mainly positive connected to Streptococcus species. Furthermore, we investigated the functional potentials of the microbiome and identified a set of microbial marker genes associated with chronic erythematous candidiasis. Some of these genes enriching in chronic erythematous candidiasis are involved in eukaryotic ribosome, putative glutamine transport system, and cytochrome bc1 complex respiratory unit. Altogether, this study revealed the changes of oral microbial composition, the co-occurrence between C. albicans and oral bacteria, as well as the changes of microbial marker genes during chronic erythematous candidiasis, which provides evidence of oral microbiome as a target for the treatment and prevention of chronic erythematous candidiasis.


Assuntos
Candidíase Bucal , Microbiota , Micrococcaceae , Humanos , Metagenômica
9.
Curr Microbiol ; 78(10): 3804-3810, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34468853

RESUMO

During our studies focused on the microorganism diversity and community structure of Populus euphratica at Ebinur lake wetland nature reserve in Xinjiang Uyghur Autonomous Region, PR China, a Gram-positive, aerobic, short rod-shaped bacterium without flagellum, designated as MD2T, was isolated from a piece of resina on Populus euphratica. The isolate grew at temperature of 10-45 °C (optimum 37 °C), pH of 7.0-12.0 (optimum pH 8.0) and NaCl concentration of 1-18% (optimum 3%, w/v). Based on the 16S rRNA gene sequences and the phylogenetic analysis, the strain shared the highest sequence similarities to Nesterenkonia alkaliphila JCM 19766T (96.3%), Nesterenkonia populi KCTC 29119T (95.9%), Nesterenkonia alba CCTCC AB 207011T (95.5%), and was placed within the radiation of Nesterenkonia species in the phylogenetic trees. The draft genome of the isolate was sequenced, which comprised 3,739,891 bp with G + C content of 63 mol%, and was annotated to contain 3614 protein-coding genes, 44 tRNA genes and 5 rRNA genes. Chemotaxonomic analysis indicated that the main respiratory quinones were MK-8 and MK-9, the predominant cellular fatty acids were anteiso-C17:0, anteiso-C15:0 and iso-C16:0, the major polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol andphosphatidylinositol. According to the phenotypic, chemotaxonomic and phylogenetic features, strain MD2T is considered to represent a novel species, for which the name Nesterenkonia ebinurensis sp. nov. is proposed. The type strain is MD2T (= KCTC 52999T = MCCC 1K03343T).


Assuntos
Populus , Técnicas de Tipagem Bacteriana , DNA Bacteriano/genética , Ácidos Graxos/análise , Micrococcaceae , Hibridização de Ácido Nucleico , Peptidoglicano , Fosfolipídeos/análise , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
10.
Sci Rep ; 11(1): 15638, 2021 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-34341372

RESUMO

Although many bacteria have the potential to remove antibiotic residues from environmental niches, the benefits of using antibiotic-degrading bacteria to manage antibiotic pollution should be assessed against the risk of the potential expansion of antimicrobial resistance. This study investigated the antibiotic resistance pattern of the bacterium Arthrobacter nicotianae OTC-16, which shows substantial biodegradation of oxytetracycline (OTC)/tetracycline. The results showed that this strain could be resistant to at least seven categories of 15 antibiotics, based on antimicrobial susceptibility testing. The genome of A. nicotianae OTC-16 contains one chromosome (3,643,989 bp) and two plasmids (plasmid1, 123,894 bp and plasmid2, 29,841 bp). Of the 3,561 genes isolated, eight were related to antibiotic resistance. During OTC degradation by the strain OTC-16, the expression of ant2ia, sul1, tet33, and cml_e8 in the plasmid, and one gene (tetV) in the chromosome were tracked using real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Only the plasmid-derived resistance genes were up-regulated in the presence of OTC. The presence of OTC increased the tolerance of strain OTC-16 to streptomycin sulphate. The findings of this study can help deepen our understanding of the behavioural characteristics of resistance genes and adaptive evolution of drug-resistant bacteria.


Assuntos
Resistência Microbiana a Medicamentos , Genômica , Oxitetraciclina , Biodegradação Ambiental , Micrococcaceae , Inibidores da Síntese de Proteínas
11.
Analyst ; 146(19): 5855-5865, 2021 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-34378550

RESUMO

Plant growth-promoting rhizobacteria (PGPR) play a crucial role in biological control and pathogenic defense on and within plant tissues, however the mechanisms by which plants associate with PGPR to elicit such beneficial effects need further study. Here, we present time-of-flight secondary ion mass spectrometry (ToF-SIMS) imaging of Brachypodium distachyon (Brachypodium) seeds with and without exposure to two model PGPR, i.e., Gram-negative Pseudomonas fluorescens SBW25 (P.) and Gram-positive Arthrobacter chlorophenolicus A6 (A.). Delayed image extraction was used to image PGPR-treated seed sections to reveal morphological changes. ToF-SIMS spectral comparison, principal component analysis (PCA), and two-dimensional (2D) imaging show that the selected PGPR have different effects on the host seed surface, resulting in changes in chemical composition and morphology. Metabolite products and biomarkers, such as flavonoids, phenolic compounds, fatty acids, and indole-3-acetic acid (IAA), were identified on the PGPR-treated seed surfaces. These compounds have different distributions on the Brachypodium seed surface for the two PGPR, indicating that the different bacteria elicit distinct responses from the host. Our results illustrate that ToF-SIMS is an effective tool to study plant-microbe interactions and to provide insightful information with submicrometer lateral resolution of the chemical distributions associated with morphological features, potentially offering a new way to study the mechanisms underlying beneficial roles of PGPR.


Assuntos
Brachypodium , Micrococcaceae , Imagem Molecular , Sementes
12.
J Environ Manage ; 298: 113546, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34435573

RESUMO

Microbial Fuel Cell (MFC) is an innovative bio-electrochemical approach which converts biochemical energy inherent in wastewater into electrical energy, thus contributing to circular economy. Five electrogenic bacteria, Kocuria rosea (GTPAS76), two strains of Bacillus circulans (GTPO28 and GTPAS54), and two strains of Corynebacterium vitaeruminis (GTPO38 and GTPO42) were isolated from a common effluent treatment plant (CETP) and were used individually as well as in consortium form to run double chambered "H" type microbial fuel cell. Individually they could produce voltage in the range of 0.4-0.7 V in the MFC systems. Consortium developed using GTPO28, GTPO38, GTPAS54 and GTPAS76 were capable of producing voltage output of 0.8 V with 81.81 % and 64 % COD and BOD reduction, respectively. The EPS production capacity and electricity generation by the isolated bacteria correlated significantly (r = 0.72). Various parameters like, effect of preformed biofilm, length of salt bridge and its reuse, aeration, substrate concentration and external resistance were studied in detail. The study emphasizes on improving the commercialization aspect of MFC with repeated use of salt bridge and improving wastewater treatment potential after optimization of MFC system. Polarization curve and power density trends were studied in optimized MFC. A maximum power density and current density achieved were 18.15 mW/m2 and 370.37 mA/m2, respectively using 5 mM sodium benzoate. This study reports the use of sodium benzoate as a substrate along with reusing of the salt bridge in MFC study with promising results for BOD and COD reduction, proving it to be futuristic technology for bio-based circular ecosystem development.


Assuntos
Fontes de Energia Bioelétrica , Hidrocarbonetos Aromáticos , Bacillus , Biodegradação Ambiental , Corynebacterium , Ecossistema , Eletricidade , Eletrodos , Micrococcaceae , Águas Residuárias
13.
J Periodontal Res ; 56(6): 1079-1090, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34449089

RESUMO

BACKGROUND: Vegetarian diets are known to reduce inflammation. The objective of this study was to test the hypothesis that reduced inflammation associated with a vegetarian diet would promote a more commensal subgingival bacterial profile. METHODS: A total of 39 periodontally healthy subjects (PD ≤3 mm, bleeding on probing <10%) were enrolled. Dietary intake was assessed by a food frequency questionnaire. A comprehensive periodontal examination was performed. Gingival crevicular fluid (GCF) and subgingival plaque samples were collected. GCF samples were assessed for interleukin-1ß, interleukin-6, interleukin-8, tumor necrosis factor-alpha, and interleukin-10. Plaque samples were analyzed for bacteria using 16S rDNA sequencing on an Illumina platform. GenBank database was used for taxonomy classification. RESULTS: Twenty-three subjects were categorized as vegetarian and 16 non-vegetarians. Clinical periodontal measures and GCF cytokine levels were statistically comparable between the two groups. Measures of microbial richness and alpha diversity were also comparable between the two dietary groups. Vegetarians harbored higher levels of phyla associated with gingival health (Actinobacteria, and Proteobacteria). Two species known to be associated with periodontitis (Mogibacterium timidum and Veillonella rogosae) were prominent in non-vegetarians. Pearson's correlations between GCF inflammatory cytokines and microbial taxa differed between vegetarians and non-vegetarians. In vegetarians, the anti-inflammatory cytokine IL-10 positively correlated with two species known to be associated with periodontal health (Peptidiphaga sp. HMT183 and Rothia aeria). CONCLUSIONS: Diet is directly and indirectly associated with the microbial composition of subgingival plaque. A vegetarian diet may promote a subgingival microbiota associated with periodontal health.


Assuntos
Citocinas , Microbiota , Clostridiales , Estudos Transversais , Citocinas/análise , Líquido do Sulco Gengival/química , Humanos , Micrococcaceae , Vegetarianos , Veillonella
14.
Chemosphere ; 285: 131466, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34271468

RESUMO

Here, we explore effects of metallophore-producing rhizobacteria on the plant availability of germanium (Ge) and rare earth elements (REEs). Five isolates of the four species Rhodococcus erythropolis, Arthrobacter oxydans, Kocuria rosea and Chryseobacterium koreense were characterized regarding their production of element-chelators using genome-mining, LC-MS/MS analysis and solid CAS-assay. Additionally, a soil elution experiment was conducted in order to identify isolates that increase solubility of Ge and REEs in soil solution. A. oxydans ATW2 and K. rosea ATW4 released desferrioxamine-, bacillibactin- and surfactin-like compounds that mobilized Ge and REEs as well as P, Fe, Si and Ca in soil. Subsequently, oat, rapeseed and reed canary grass were cultivated on soil and sand and treated with cells and iron depleted culture supernatants of A. oxydans ATW2 and K. rosea ATW4. Inoculation increased plant yield and shoot phosphorus (P), manganese (Mn), Ge and REE concentrations. However, effects of the inoculation varied substantially between the growth substrates and plant species. On sand, A. oxydans ATW2 increased accumulation of REEs in all plant species and root-shoot translocation in rapeseed, while K. rosea ATW4 enhanced REE accumulation in rapeseed only, without effects on other plant species. Sand-cultured oat plants showed increased Ge accumulation and root-shoot translocation in presence of A. oxydans ATW2 cells and K. rosea ATW4 supernatant; however, there was no effect on other plant species, irrespective the growth substrate used. In contrast, soil-cultured rapeseed showed enhanced REE accumulation in presence of cells of A. oxydans ATW2 while there were no effects on other plant species and Ge. The processes involved are not yet fully understood. Nevertheless, we demonstrated that chemical microbe-soil-plant relationships influence plant availability of nutrients together with Ge and REEs, which has major implications on our understanding of biogeochemical element cycling and development of sustainable bioremediation and biomining technologies.


Assuntos
Germânio , Metais Terras Raras , Micrococcaceae , Poluentes do Solo , Cromatografia Líquida , Chryseobacterium , Metais Terras Raras/análise , Rizosfera , Rhodococcus , Solo , Poluentes do Solo/análise , Espectrometria de Massas em Tandem
15.
Molecules ; 26(14)2021 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-34299660

RESUMO

Arthrobacter nicotinovorans decomposes nicotine through the pyridine pathway. 6-hydroxypseudooxynicotine 2-oxidoreductase (also named ketone dehydrogenase, Kdh) is an important enzyme in nicotine degradation pathway of A. nicotinovorans, and is responsible for the second hydroxylation of nicotine. Kdh belongs to the molybdenum hydroxylase family, and catalyzes the oxidation of 6-hydroxy-pseudooxynicotine (6-HPON) to 2,6-dihydroxy-pseudooxynicotine (2,6-DHPON). We determined the crystal structure of the Kdh holoenzyme from A. nicotinovorans, with its three subunits KdhL, KdhM, and KdhS, and their associated cofactors molybdopterin cytosine dinucleotide (MCD), two iron-sulfur clusters (Fe2S2), and flavin adenine dinucleotide (FAD), respectively. In addition, we obtained a structural model of the substrate 6-HPON-bound Kdh through molecular docking, and performed molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) calculations to unveil the catalytic mechanism of Kdh. The residues Glu345, Try551, and Glu748 of KdhL were found to participate in substrate binding, and Phe269 and Arg383 of KdhL were found to contribute to stabilize the MCD conformation. Furthermore, site-directed mutagenesis and enzymatic activity assays were performed to support our structural and computational results, which also revealed a trend of increasing catalytic efficiency with the increase in the buffer pH. Lastly, our electrochemical results demonstrated electron transfer among the various cofactors of Kdh. Therefore, our work provides a comprehensive structural, mechanistic, and functional study on the molybdenum hydroxylase Kdh in the nicotine degradation pathway of A. nicotinovorans.


Assuntos
Proteínas de Bactérias/química , Micrococcaceae/enzimologia , Oxigenases de Função Mista/química , Simulação de Acoplamento Molecular , Molibdênio/química , Nicotina/química , Proteínas de Bactérias/genética , Clonagem Molecular , Nucleotídeos de Citosina/química , Nucleotídeos de Citosina/genética , Micrococcaceae/genética , Oxigenases de Função Mista/genética , Molibdênio/metabolismo , Nicotina/metabolismo , Pterinas/química , Relação Estrutura-Atividade
16.
J Vet Diagn Invest ; 33(6): 1089-1095, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34293996

RESUMO

Avian influenza surveillance is a requirement for commercial trade in ostrich products, but influenza A viruses (IAVs) have proven difficult to isolate from ostrich tracheal swabs that test positive using molecular methods. We hypothesized that microbes unique to the ostrich trachea propagate in the transport medium after sampling and affect viral viability. We cultured tracheal swabs from 50 ostriches on 4 farms in South Africa, and recovered and identified 13 bacterial, 1 yeast, and 2 fungal species. Dietzia sp. had not been identified previously in the oropharyngeal tract of a bird, to our knowledge. The bacteria were tested for antimicrobial susceptibility, and most aerobic species, except for Streptococcus sp. and Pseudomonas sp., were sensitive to enrofloxacin; all were susceptible to sulfonamide. Virus inhibition experiments determined that ostrich-source Streptococcus sp., Pantoea sp., and Citrobacter freundii produced extracellular metabolites that caused a substantial reduction in the IAV titers of 99.9%. Streptomyces, Corynebacterium, Staphylococcus, Arthrobacter gandavensis, Pseudomonas putida, and Acinetobacter spp. similarly reduced the viability of IAV from 77.6% to 24.1%. Dietzia appeared to have no effect, but Rothia dentocariosa, Rhodotorula spp., and Clostridium spp. slightly increased the viability of IAV by 25.9, 34.9, and 58.5%, respectively.


Assuntos
Arthrobacter , Vírus da Influenza A , Influenza Aviária , Struthioniformes , Animais , Fazendas , Micrococcaceae
17.
Sci Rep ; 11(1): 13659, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34211018

RESUMO

In this study, two highly thermotolerant and methanol-tolerant lipase-producing bacteria were isolated from cooking oil and they exhibited a high number of catalytic lipase activities recording 18.65 ± 0.68 U/mL and 13.14 ± 0.03 U/mL, respectively. Bacterial isolates were identified according to phenotypic and genotypic 16S rRNA characterization as Kocuria flava ASU5 (MT919305) and Bacillus circulans ASU11 (MT919306). Lipases produced from Kocuria flava ASU5 showed the highest methanol tolerance, recording 98.4% relative activity as well as exhibited high thermostability and alkaline stability. Under the optimum conditions obtained from 3D plots of response surface methodology design, the Kocuria flava ASU5 biocatalyst exhibited an 83.08% yield of biodiesel at optimized reaction variables of, 60 â—‹C, pH value 8 and 1:2 oil/alcohol molar ratios in the reaction mixture. As well as, the obtained results showed the interactions of temperature/methanol were significant effects, whereas this was not noted in the case of temperature/pH and pH/methanol interactions. The obtained amount of biodiesel from cooking oil was 83.08%, which was analyzed by a GC/Ms profile. The produced biodiesel was confirmed by Fourier-transform infrared spectroscopy (FTIR) approaches showing an absorption band at 1743 cm-1, which is recognized for its absorption in the carbonyl group (C=O) which is characteristic of ester absorption. The energy content generated from biodiesel synthesized was estimated as 12,628.5 kJ/mol. Consequently, Kocuria flava MT919305 may provide promising thermostable, methanol-tolerant lipases, which may improve the economic feasibility and biotechnology of enzyme biocatalysis in the synthesis of value-added green chemicals.


Assuntos
Proteínas de Bactérias/metabolismo , Biocombustíveis , Lipase/metabolismo , Metanol/metabolismo , Micrococcaceae/enzimologia , Óleos Vegetais/metabolismo , Biocatálise , Biocombustíveis/análise , Biocombustíveis/microbiologia , Biotecnologia/métodos , Culinária , Gorduras Insaturadas na Dieta/metabolismo , Micrococcaceae/metabolismo
18.
Sci Total Environ ; 794: 148719, 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34214821

RESUMO

Phthalic acid esters (PAEs) are a class of biologically accumulated carcinogenic and teratogenic toxic chemicals that exist widely in the environment. This study, Pseudarthrobacter defluvii E5 was isolated from agricultural soils and showed efficient PAEs-degradation and -mineralization abilities for five PAEs, and encouraging PAEs tolerance and bioavailable range for dibutyl phthalate (DBP) and bis(2-ethylhexyl) phthalate (DEHP) (0.25-1200 mg/L). The complete catalytic system in E5 genome enables PAEs to be degraded into monoester, phthalate (PA) and Protocatechuic acid (PCA), which eventually enter the tricarboxylic acid cycle (TCA cycle). The preferred PAEs-metabolic pathway in soil by E5 is the metabolism induced by enzymes encoded by pehA, mehpH, pht Operon and pca Operon. For the first time, two para-homologous pht gene clusters were found to coexist on the plasmid and contribute to PAEs degradation. Further study showed that P. defluvii E5 has a broad application prospect in microplastics-contaminated environments.


Assuntos
Ácidos Ftálicos , Plásticos , Dibutilftalato , Ésteres , Micrococcaceae , Ácidos Ftálicos/toxicidade
19.
J Basic Microbiol ; 61(8): 745-756, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34228381

RESUMO

Antagonistic bacteria can act as biocontrol agents against various phytopathogens. Recently, Arthrobacter spp. demonstrated antifungal activity, but were not further characterized. In this study, the antimicrobial activity of Arthrobacter humicola strains M9-1A, M9-2, and M9-8, and Arthrobacter psychrophenolicus strain M9-17 were evaluated against nine plant pathogens in vitro, and their cell-free filtrates were additionally assessed for inhibition of Alternaria alternata and suppression of black mold disease on tomato fruit. Results indicated that A. humicola M9-1A and A. psychrophenolicus M9-17 were the most inhibitory, reducing growth of seven of the pathogens studied. Cell-free filtrates of A. psychrophenolicus M9-17 reduced the growth of most pathogens. All cell-free bacterial filtrates, except those from A. humicola M9-2, suppressed black mold on tomato fruit. Disk diffusion assays with ethyl acetate soluble culture filtrate extracts of all bacteria reduced the mycelial growth of A. alternata. Clear inhibition zones were observed for A. psychrophenolicus M9-17 extracts using drop bioassays. The antifungal compound N-acetyltryptamine was purified and characterized from the A. psychrophenolicus M9-17 cell-free ethyl acetate soluble extract. This study suggests that antibiosis may play a key role in the antimicrobial activity of Arthrobacter spp.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Arthrobacter/isolamento & purificação , Arthrobacter/metabolismo , Compostagem , Alternaria/efeitos dos fármacos , Antibiose/efeitos dos fármacos , Antifúngicos/química , Antifúngicos/farmacologia , Frutas/microbiologia , Lycopersicon esculentum/microbiologia , Micrococcaceae , Doenças das Plantas/microbiologia
20.
J Zoo Wildl Med ; 52(2): 749-754, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34130422

RESUMO

Transmission of tuberculosis typically requires close and prolonged contact with an infected individual. However, several cases of transmission between elephants and from elephants to humans or other animals without direct contact or over long distances have been reported. Elephants have been shown to be capable of producing aerosolized bacterial droplets, suggesting a possible route of transmission that is magnified by the size and force of the elephant respiratory tract. To investigate the dispersion and viability of aerosolized bacteria generated from the elephant respiratory tract, a pre-existing model with a proxy organism was used. A six-stage Andersen sampler was used to detect the proxy organism, a commensal elephant respiratory bacterium, at different locations around an elephant barn at a zoo. The amount of proxy organism detected at various time points and distances from the elephants indicates they are capable of dispersing viable bacterial aerosols further than humans can. The concentration of these aerosols is dependent on proximity to the elephants and does not remain at a high level for prolonged periods of time. These findings support the model of aerosol-mediated transmission of bacteria from elephants and can be used to improve disease management practices and prevent the spread of pathogens from elephants in zoos and other facilities.


Assuntos
Microbiologia do Ar , Elefantes/microbiologia , Micrococcaceae/isolamento & purificação , Aerossóis , Animais , Feminino , Masculino , Mycobacterium tuberculosis , Tuberculose/microbiologia , Tuberculose/transmissão , Tuberculose/veterinária
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