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1.
PLoS One ; 15(7): e0235560, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32614907

RESUMO

The present study investigated the effects of four woody forages (Moringa oleifera Lam (MOL), fermented MOL, Folium mori (FM) and fermented FM) on biodiversity and bioactivity of aerobic culturable gut bacteria of tilapia (Oreochromis niloticus) by a traditional culture-dependent method. A total of 133 aerobic culturable isolates were recovered and identified from the gut of tilapia, belonging to 35 species of 12 genera in three bacterial phyla (Firmicutes, Actinobacteria and Proteobacteria). Among them, 6 bacterial isolates of Bacillus baekryungensis, Bacillus marisflavi, Bacillus pumilus, Bacillus methylotrophicus, Proteus mirabilis and Pseudomonas taiwanensis were isolated from all the five experimental groups. The Bray-Curtis analysis showed that the bacterial communities among the five groups displayed obvious differences. In addition, this result of bioactivity showed that approximate 43% of the aerobic culturable gut bacteria of tilapia displayed a distinct anti-bacterial activity against at least one of four fish pathogens Streptococcus agalactiae, Streptococcus iniae, Micrococcus luteus and Vibrio parahemolyticus. Furthermore, Bacillus amyloliquefaciens and Streptomyces rutgersensis displayed strong activity against all four indicator bacteria. These results contribute to our understanding of the intestinal bacterial diversity of tilapia when fed with woody forages and how certain antimicrobial bacteria flourished under such diets. This can aid in the further exploitation of new diets and probiotic sources in aquaculture.


Assuntos
Bactérias/isolamento & purificação , Ciclídeos/microbiologia , Microbioma Gastrointestinal , Aerobiose , Animais , Antibacterianos/farmacologia , Bacillus/efeitos dos fármacos , Bacillus/genética , Bacillus/isolamento & purificação , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/genética , Biodiversidade , Dieta/veterinária , Microbioma Gastrointestinal/efeitos dos fármacos , Intestinos/microbiologia , Testes de Sensibilidade Microbiana , Filogenia , RNA Ribossômico 16S/química , RNA Ribossômico 16S/metabolismo , Streptococcus/efeitos dos fármacos , Streptococcus/genética , Streptococcus/isolamento & purificação
2.
Food Chem ; 331: 127348, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32619908

RESUMO

Information concerning food composition, including information on its glucose content, is essential for modern food industry due to greater consumer awareness and expectations. In this work, the gene encoding d-glucose dehydrogenase (GDH) from Bacillus Natto was expressed in Escherichia coli BL21(DE3) firstly. Ni-IDA column was used for the purification of GDH. Then, the purified GDH was used to construct a color system with stable and effective measurement of concentration of d-glucose. The smart phone photographing and the software Microsoft Photoshop have been used in the system for determination of the color. The enzymatic analysis system can detect the concentration of d-glucose from 5 mM to 40 mM, and other various sugars has no interference to the system. The system was used to quantitatively detect the concentration of d-glucose in honey. The system can be used for convenient and rapid detection of d-glucose in food, especially for large numbers of samples.


Assuntos
Análise de Alimentos/métodos , Glucose/análise , Mel/análise , Smartphone , Bacillus/genética , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Cor , Escherichia coli/genética , Análise de Alimentos/instrumentação , Glucose 1-Desidrogenase/genética , Glucose 1-Desidrogenase/metabolismo , Concentração de Íons de Hidrogênio , Limite de Detecção , Software
3.
Arch Microbiol ; 202(9): 2367-2371, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32572518

RESUMO

A novel Bacillus strain, designated SYSU G01002T, was isolated from a sediment sample collected from tepid spring in Tengchong, Yunnan province, south-west PR China. The 16S rRNA gene sequence analysis showed that the strain SYSU G01002T shared the highest sequence identity with the type strain of Bacillus alkalitolerans (97.7%). Strain SYSU G01002T grew at pH 6.0-8.0 (optimum, pH 7.0), at 28-55 °C (optimum, 45 °C) and in the presence of 0-2.5% (w/v) NaCl (optimum in the absence of NaCl). It contained meso-2,6-diaminopimelic acid as the cell-wall diamino acid and MK-7 as isoprenoid quinone. The major cellular fatty acids were iso-C15:0, iso-C17:0 and C16:0. The polar were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and unidentified phospholipid. The genomic DNA G + C content was 38.0 mol %. The digital DNA-DNA hybridization and average nucleotide identity values between SYSU G01002T and closely related members of the genus Bacillus were below the cut-off level recommended for interspecies identity. Based on the above results, strain SYSU G01002T represents a novel species of the genus Bacillus, for which the name Bacillus tepidiphilus sp. nov. is proposed. The type strain, SYSU G01002T (= KCTC 43131T = CGMCC 1.17491T).


Assuntos
Bacillus/classificação , Água Doce/microbiologia , Bacillus/química , Bacillus/genética , Bacillus/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , Ácido Diaminopimélico/análise , Ácidos Graxos/análise , Hibridização de Ácido Nucleico , Fosfolipídeos/análise , Filogenia , RNA Ribossômico 16S/genética , Especificidade da Espécie
4.
Arch Microbiol ; 202(9): 2373-2378, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32583126

RESUMO

A Gram-positive, endospore-forming, rod-shaped bacterium with a single flagellum, and a motile strain, designated CX253, was isolated from bioaerosols. The isolate is facultatively anaerobic, is able to grow at 25-45 â„ƒ (optimum 37 â„ƒ) and pH 6.5-10.0 (optimum 7.5), and can tolerate up to 5.0% NaCl (w/v) under aerobic conditions. The diagnostic diamino acid in the cell wall of strain CX253T is meso-diaminopimelic acid, while major isoprenoid quinone is menaquinone 6 (MK-6) along with a smaller amount of MK-7 (20%). The polar lipid profile is composed of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phospholipids and glycolipids. The major cellular fatty acid is iso-C15:0 and anteiso-C15:0. Phylogenetic analysis based on 16S rRNA gene and genome sequence grouped strain CX253T into the genus Bacillus. The strain was most closely related to Bacillus thermotolerans CCTCC AB 2012108 T by comparison of 16S rRNA gene sequence (97.2% similarity) and to Bacillus wudalianchiensis CCTCC AB 2015266 T by comparison of gyrB gene sequence (80.1% similarity). The draft genome of strain CX253T comprised 3,929,195 bp with a G + C content of 43.3 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain CX253T and phylogenetically related Bacillus species were lower than 95% and 70%, respectively. Thus, the polyphasic evidence generated through phenotypic, chemotaxonomic and genomic methods confirmed that strain CX253T (= GDMCC 1.1608 T = KACC 21318 T) was a novel species of the genus Bacillus, for which the name Bacillus aerolatus sp. nov. is proposed.


Assuntos
Aerossóis , Bacillus/classificação , Microbiologia Ambiental , Bacillaceae/genética , Bacillus/genética , Bacillus/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , Parede Celular/química , Ácido Diaminopimélico/análise , Ácidos Graxos/análise , Glicolipídeos/análise , Hibridização de Ácido Nucleico , Fosfolipídeos/análise , Filogenia , RNA Ribossômico 16S/genética , Especificidade da Espécie
5.
Arch Microbiol ; 202(8): 2135-2145, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32519019

RESUMO

In Pakistan, 55% of textile exports are contributed by textile-units of Faisalabad. The effluents of these textile units, being discharged without any treatment, contain the contamination of a huge amount of synthetic azo dyes. The objective of the current research was to evaluate the contribution of an azoreductase-encoding gene (azrS) from a pre-characterized azo dye decolorizing bacterial strain Bacillus sp. MR-1/2 in a high copy number host system (pUC19-T7-Top-T) of Escherichia coli strain DH5α followed by in-silico prediction of azoreductase enzyme (AzrS) function. The recombinant cells that contained azrS had a significantly higher rate of color removal in congo red and reactive black-5 dyes when compared to wild-type MR-1/2 and E. coli DH5α after 72 h of incubation. Moreover, we were able to show that the recombinant strain significantly reduced the values of all tested parameters (pH, EC, turbidity, TSS, and COD) in actual wastewater. In support of our results, it was also predicted through bioinformatics analysis that the deduced azoreductase protein of strain MR-1/2 is linked with the dye decolorization ability of the strain through NAD(P)H-ubiquinone: oxidoreductase activity. Furthermore, we also found that the deduced protein resembled closely related proteins of protein databank in many features, yet some unique features were predicted in the enzyme activity of strain MR-1/2. It was concluded that the recombinant strain could be examined in pilot-scale experiments for textile wastewater treatment.


Assuntos
Compostos Azo/metabolismo , Bacillus/enzimologia , Bacillus/genética , NADH NADPH Oxirredutases/genética , NADH NADPH Oxirredutases/metabolismo , Águas Residuárias/microbiologia , Purificação da Água , Compostos Azo/química , Biodegradação Ambiental , Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica/genética , Paquistão
6.
Arch Microbiol ; 202(7): 1785-1794, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32382765

RESUMO

Bacillus spp. have a wide range of activities in the biocontrol potential against various phytopathogens. This study focuses on the biocontrol potential of two species belonging to the same genera, as Bacillus subtilis (SSR2I) and Bacillus flexus (AIKDL) have contrasting activity under in vivo and in vitro conditions. In this study, two medicinal plants-associated bacteria showing antagonistic activity against wilt-causing pathogens were selected and identified as B. subtilis (SSR2I) and B. flexus (AIKDL) based on 16S rRNA gene sequencing. Crude extracts of these bacteria showed that chloroform extracts of AIKDL, and ethyl acetate extraction of SSR2I showed effective potential inhibition of both the wilt-causing pathogens in the well-diffusion method. PCR-based detection of antimicrobial peptide genes revealed the presence of five genes in B. subtilis and none in B. flexus. On the basis of in vivo analysis, the isolate SSR2I showed reduced disease incidence and enhanced biocontrol efficiency against Ralstonia solanacearum and Fusarium oxysporum compared with AIKDL and control plants. Further, the isolates SSR2I also enhanced the induced systemic resistance (ISR) against both the pathogens compared to the control. However, the isolate AIKDL showed enhanced ISR against F. oxysporum-treated plants, but not against R. solanacearum-treated plants. The results indicated that even though the isolates had strong antagonistic potential under in vitro conditions, their biocontrol efficiency differed in in vivo condition. On the basis of the overall performance, the isolate SSR2I could be formulated as biocontrol agents against both the wilt-causing pathogens tested in this study.


Assuntos
Bacillus/genética , Bacillus/metabolismo , Fenômenos Fisiológicos Bacterianos , Fungos/fisiologia , Interações Microbianas , Controle Biológico de Vetores , Plantas/microbiologia , Peptídeos Catiônicos Antimicrobianos/genética , Bacillus/classificação , Desenvolvimento Vegetal/fisiologia , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , RNA Ribossômico 16S/genética
7.
PLoS One ; 15(4): e0231274, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32271828

RESUMO

We evaluated the minimum inhibitory concentrations of clindamycin and erythromycin toward 98 Bacillus licheniformis strains isolated from several types of fermented soybean foods manufactured in several districts of Korea. First, based on recent taxonomic standards for bacteria, the 98 strains were separated into 74 B. licheniformis strains and 24 B. paralicheniformis strains. Both species exhibited profiles of erythromycin resistance as an acquired characteristic. B. licheniformis strains exhibited acquired clindamycin resistance, while B. paralicheniformis strains showed unimodal clindamycin resistance, indicating an intrinsic characteristic. Comparative genomic analysis of five strains showing three different patterns of clindamycin and erythromycin resistance identified 23S rRNA (adenine 2058-N6)-dimethyltransferase gene ermC and spermidine acetyltransferase gene speG as candidates potentially involved in clindamycin resistance. Functional analysis of these genes using B. subtilis as a host showed that ermC contributes to cross-resistance to clindamycin and erythromycin, and speG confers resistance to clindamycin. ermC is located in the chromosomes of strains showing clindamycin and erythromycin resistance and no transposable element was identified in its flanking regions. The acquisition of ermC might be attributable to a homologous recombination. speG was identified in not only the five genome-analyzed strains but also eight strains randomly selected from the 98 test strains, and deletions in the structural gene or putative promoter region caused clindamycin sensitivity, which supports the finding that the clindamycin resistance of Bacillus species is an intrinsic property.


Assuntos
Bacillus licheniformis/genética , Bacillus/genética , Clindamicina/farmacologia , Farmacorresistência Bacteriana/genética , Genes Bacterianos , Genômica , Bacillus/efeitos dos fármacos , Bacillus/crescimento & desenvolvimento , Bacillus licheniformis/classificação , Bacillus licheniformis/efeitos dos fármacos , Bacillus licheniformis/crescimento & desenvolvimento , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/genética , Bacillus subtilis/crescimento & desenvolvimento , Sequência de Bases , Farmacorresistência Bacteriana/efeitos dos fármacos , Eritromicina/farmacologia , Testes de Sensibilidade Microbiana
8.
J Biosci Bioeng ; 130(1): 48-53, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32224010

RESUMO

Macrolactins (MLNs) have attracted considerable attention due to their antibacterial and antiviral properties. Here, the MLN production of Bacillus sp. strain IMDGX0108 was improved using a breeding strategy of atmospheric room temperature plasma (ARTP) technique. Combining with a selection procedure based on the colony morphology and specific growth rate index (SGRI), two genetically stable mutants A29 and A72 were identified. The MLN production of A29 and A72 was 35.2% and 52.8% greater than that of the parent strain, respectively. The best-performing mutant A72 was subjected to RNA-sequence analysis. Five pathways were significantly enriched, and fatty acid bioprocesses might play an important role in improving the production of MLNs. The combined strategy developed herein (i.e., ARTP mutation plus an efficient screening procedure) might be an appropriate method by which to obtain strains overproducing MLNs.


Assuntos
Bacillus/efeitos dos fármacos , Bacillus/crescimento & desenvolvimento , Alcaloides Indólicos/metabolismo , Gases em Plasma/farmacologia , Bacillus/química , Bacillus/genética , Ácidos Graxos/metabolismo , Cinética , Mutação
9.
Arch Microbiol ; 202(7): 1749-1756, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32335717

RESUMO

ß-glucanases are widely applied in biological control, brewing and feed industries; however, there are seldom studies of ß-glucanases in probiotics. Here, ß-glucanase genes were cloned from Bacillus licheniformis, Lactobacillus fermentum and L. johnsonii. ß-glucanase genes, as blg, lfg and ljg isolated from B. licheniformis, L. fermentum and L. johnsonii were prokaryotic expressed to obtain recombinant strains BL, LF and LJ, respectively. Directed mutations in these genes were introduced by sequential error-prone PCR. Results showed that ß-glucanase activities in three mutants mblg, mlfg and mljg were 1.94-, 2.72- and 1.29-fold higher than the BL, LF and LJ, respectively. Mutation sites analysis showed substitutions at Ser370Gly and Leu395Phe in mblg; Arg169His and Asn302Ser in mlfg; Val132Met, Ser226Asn, and Asp355Gly in mljg. Spatial structural predictions revealed the numbers and positions of α-helices and ß-strands in the three mutants were altered, which might result in ß-glucanase activity increasement. Analysis of ß-glucanase properties revealed no significant differences in the optimal temperatures and pH between mutant and wild-type strains. However, mlfg and mljg exhibited greater thermal stability at 30-50 â„ƒ than the wild-type strains, and mblg improved pH stability compared with wild-type strain. This is the first report about ß-glucanase-encoding genes in L. fermentum and L. johnsonii. These findings provide an efficient way to improve the activity of ß-glucanase.


Assuntos
Bacillus , Estabilidade Enzimática/genética , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Lactobacillus , Probióticos , Bacillus/enzimologia , Bacillus/genética , Clonagem Molecular , Concentração de Íons de Hidrogênio , Lactobacillus/enzimologia , Lactobacillus/genética , Mutação , Reação em Cadeia da Polimerase , Temperatura
10.
Int J Food Microbiol ; 323: 108573, 2020 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-32203753

RESUMO

Spoilage microorganisms can occur at many points throughout food production systems. Bacillus spp. and Paenibacillus spp. are important aerobic spoilage bacteria in various sectors of the food industry. In this study, we developed a rapid detection and quantification technique for Bacillus group-specific and the genus Paenibacillus by using multiplex quantitative PCR (mqPCR). The 1st was the Bacillus cereus group containing B. cereus and B. weihenstephanensis; the 2nd was the B. subtilis group containing B. subtilis, B. licheniformis, B. safensis, and B. pumilus; the 3rd was the B. simplex group containing B. megaterium and B. simplex; and the 4th was the genus Paenibacillus. Depending on the assays, the detection limit was 10 copy numbers. In addition, mqPCR assays were validated by spiking potato salad and milk samples with four strains; B. weihenstephanensis, B. licheniformis, B. megaterium, and P. lautus. The detection dynamic range for potato salad was 105 CFU/mL-101 CFU/mL with B. weihenstephanensis and B. licheniformis, and 105 CFU/mL-102 CFU/mL with B. megaterium and P. lautus, while, for milk, all strains were 105 CFU/mL-102 CFU/mL. We also stored these food matrices spiked with four bacterial suspensions (approximately 103 CFU/mL) at various temperatures. Results showed that B. weihenstephanensis and B. licheniformis were able to grow in potato salad, whereas, the populations of B. weihenstephanensis, B. licheniformis, and P. lautus increased in milk. Consequently, the mqPCR assays developed here in facilitated the differentiation, quantification, and confirmation of the presence of the psychrophilic and psychrotolerant Bacillus group and Paenibacillus spp.


Assuntos
Bacillus/genética , Microbiologia de Alimentos/métodos , Reação em Cadeia da Polimerase Multiplex , Paenibacillus/genética , Reação em Cadeia da Polimerase em Tempo Real , Animais , Bacillus/isolamento & purificação , Limite de Detecção , Leite/microbiologia , Paenibacillus/isolamento & purificação , Saladas/microbiologia
11.
J Biotechnol ; 313: 39-47, 2020 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-32198062

RESUMO

Cold-adapted pullulanase with high catalytic activity and stability is of special interest for its wide application in cold starch hydrolysis, but few pullulanases displaying excellent characteristics at ambient temperature and acidic pH have hitherto been reported. Here, a novel pullulanase from Bacillus methanolicus PB1 was successfully expressed in Escherichia coli BL21 (DE3) and determined to be a cold-adapted type I pullulanase (PulPB1) with maximum activity at 50 °C and pH 5.5. The recombinant PulPB1 showed great stability, its half-life at 50 °C was 137 h. PulPB1 can efficiently hydrolyze pullulan and amylopectin, with activities of 292 and 184 U/mg at 50 °C and pH 5.5, respectively. Moreover, the N-terminal domain of PulPB1 was found to significantly affect the enzymatic performance. Following truncation of the N-terminal domain, the activity towards pullulan decreased markedly from 292 to 141 U/mg and the half-life at 50 °C decreased from 137 to 10 h. Compared to the hydrolysis system with amyloglucosidase alone, the catalytic efficiency showed a 2.4-fold increase on combining PulPB1 with amyloglucosidase for amylopectin hydrolysis at 40 °C. This demonstrates that PulPB1 is promising for development as a superior candidate for cold amylopectin hydrolysis.


Assuntos
Amilopectina/metabolismo , Bacillus/enzimologia , Glicosídeo Hidrolases/metabolismo , Bacillus/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Temperatura Baixa , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Glucanos/metabolismo , Glicosídeo Hidrolases/genética , Concentração de Íons de Hidrogênio , Hidrólise , Proteínas Recombinantes , Amido/metabolismo
12.
mBio ; 11(1)2020 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-32098810

RESUMO

The Bacillus cereus group comprises numerous closely related species, including bioterrorism agent B. anthracis, foodborne pathogen B. cereus, and biopesticide B. thuringiensis Differentiating organisms capable of causing illness or death from those used in industry is essential for risk assessment and outbreak preparedness. However, current species definitions facilitate species-phenotype incongruences, particularly when horizontally acquired genes are responsible for a phenotype. Using all publicly available B. cereus group genomes (n = 2,231), we show that current species definitions lead to overlapping genomospecies clusters, in which 66.2% of genomes belong to multiple genomospecies at a conventional 95 average nucleotide identity (ANI) genomospecies threshold. A genomospecies threshold of ≈92.5 ANI is shown to reflect a natural gap in genome similarity for the B. cereus group, and medoid genomes identified at this threshold are shown to yield resolvable genomospecies clusters with minimal overlap (six of 2,231 genomes assigned to multiple genomospecies; 0.269%). We thus propose a nomenclatural framework for the B. cereus group which accounts for (i) genomospecies using resolvable genomospecies clusters obtained at ≈92.5 ANI, (ii) established lineages of medical importance using a formal collection of subspecies names, and (iii) heterogeneity of clinically and industrially important phenotypes using a formalized and extended collection of biovar terms. We anticipate that the proposed nomenclature will remain interpretable to clinicians, without sacrificing genomic species definitions, which can in turn aid in pathogen surveillance; early detection of emerging, high-risk genotypes; and outbreak preparedness.IMPORTANCE Historical species definitions for many prokaryotes, including pathogens, have relied on phenotypic characteristics that are inconsistent with genome evolution. This scenario forces microbiologists and clinicians to face a tradeoff between taxonomic rigor and clinical interpretability. Using the Bacillus cereus group as a model, a conceptual framework for the taxonomic delineation of prokaryotes which reconciles genomic definitions of species with clinically and industrially relevant phenotypes is presented. The nomenclatural framework outlined here serves as a model for genomics-based bacterial taxonomy that moves beyond arbitrarily set genomospecies thresholds while maintaining congruence with phenotypes and historically important species names.


Assuntos
Bacillus cereus/classificação , Bacillus cereus/genética , Genoma Bacteriano , Filogenia , Bacillus/classificação , Bacillus/genética , Bacillus anthracis/genética , Bacillus thuringiensis/genética , Bioterrorismo , Doenças Transmitidas por Alimentos/microbiologia , Genes Bacterianos/genética , Genômica , Genótipo , Fenótipo , Medição de Risco
13.
J Photochem Photobiol B ; 204: 111786, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31982671

RESUMO

Biological synthesis of nanoparticles is a growing research trend because it has numerous applications in pharmaceutics and biomedicine. The aim of this study was to obtain silver nanoparticles (AgNPs) from Bacillus sp. KFU36, a marine strain, and to assess its anticancer activity. The supernatant of Bacillus sp. KFU36 was supplemented with silver nitrate and the nanoparticles obtained were characterized spectrophotometrically and microscopically. A band of surface plasmon resonance was appeared at 430 nm, as revealed by UV-vis spectrophotometry. X-ray diffraction spectrum and Energy Dispersive Spectroscopy confirmed the crystalline and metallic structure of the AgNPs, respectively. Scanning electron microscopy revealed that the shape of the synthesized AgNPs were spherical and the size extended between 5 and 15 nm. The AgNPs were investigated for their potential anticancer effects on the cell viability, migration and apoptosis using MTT and wound-healing assays, and flow cytometry, respectively. The cytotoxic effects of these nanoparticles were evidenced by the decreasing the cell viability (as 15% at 50 µg/ml), cell density, adhesion capacity and losing the normal shape and size, and inducing the apoptosis on MCF-7 by 61% at 50 µg/ml. These findings confirm that the synthesized AgNPs exhibited superior anticancer activities and therefore could be exploited as a promising, cost-effective, and environmentally benign strategy in treating this disease in future.


Assuntos
Bacillus/química , Nanopartículas Metálicas/química , Prata/química , Apoptose/efeitos dos fármacos , Bacillus/classificação , Bacillus/genética , Neoplasias da Mama , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Feminino , Química Verde , Humanos , Células MCF-7 , Nanopartículas Metálicas/toxicidade , Filogenia
14.
Arch Microbiol ; 202(4): 887-894, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31893290

RESUMO

In this study, chromium (Cr)-tolerant bacteria were test for their efficiency in alleviating Cr stress in Cicer arietinum plants. On the basis of 16S rRNA gene analysis, the isolates were identified belonging to genus Stenotrophomonas maltophilia, Bacillus thuringiensis B. cereus, and B. subtilis. The strains produced a considerable amount of indole-3-acetic acid in a medium supplemented with tryptophan. The strains also showed siderophore production (S2VWR5 and S3VKR17), phosphorus production (S1VKR11, S3VKR2, S3VKR16, and S2VWR5), and potassium solubilization (S3VKR2, S2VWR5, and S3VKR17). Furthermore, the strains were evaluated in pot experiments to assess the growth promotion of C. arietinum in the presence of chromium salts. Bacterization improved higher root and shoot length considerably to 6.25%-60.41% and 11.3%-59.6% over the control. The plants also showed increase in their fresh weight and dry weight in response to inoculation with Cr-tolerant strains. The accumulation of Cr was higher in roots compared to shoots in both control and inoculated plants, indicating phytostabilization of Cr by C. arietinum. However, phytostabilization was found to be improved manifold in inoculated plants. Apart from the plant attributes, the amendment of soil with Cr and Cr-tolerant bacteria significantly increased the content of total chlorophyll and carotenoids, suggesting the inoculant's role in protecting plants from deleterious effects. This work suggests that the combined activity of Cr-tolerant and plant growth-promoting (PGP) properties of the tested strains could be exploited for bioremediation of Cr and to enhance the C. arietinum cultivation in Cr-contaminated soils.


Assuntos
Bacillus/metabolismo , Cromo/metabolismo , Cicer/microbiologia , Desenvolvimento Vegetal , Poluentes do Solo/metabolismo , Stenotrophomonas maltophilia/metabolismo , Estresse Fisiológico , Bacillus/genética , Biodegradação Ambiental , Cicer/efeitos dos fármacos , Cicer/metabolismo , Meios de Cultura/química , Ácidos Indolacéticos/metabolismo , Desenvolvimento Vegetal/fisiologia , RNA Ribossômico 16S/genética , Microbiologia do Solo , Stenotrophomonas maltophilia/genética
15.
Arch Microbiol ; 202(5): 1005-1013, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31932863

RESUMO

Pectinase is widely used in numerous industrial fields, including the food, wine, and paper industries. In this work, seven bacteria were isolated from orange peel and their pectinase production activity was assayed. One bacterium (OR-B2) identified as a Bacillus sp. showed the highest enzyme activity towards others. A gene encoding a pectate lyase designed as PelB-B2 in this work was amplified and heterogeneous expressed in E.coli. PelB-B2 was defined as a member of the PelB pectate lyase family after phylogenic tree analysis. 3D model of PelB-B2 was constructed by SWISS-MODEL and PelB-B2 showed conserved para-ß structure. After inducing culture and purified by Ni-affinity chromatography, the properties of the purified PelB-B2 were assayed. Optimal pH and temperature for PelB-B2 was pH 8.0 and 50 °C, respectively. PelB-B2 showed excellent pH stability and thermostability. It was stable within pH range 3.0-11.0 and retained more than 51% activity after incubation at 40 °C, 50 °C, or 60 °C for 1 h. Furthermore, we determined that PelB-B2 was a Ca2+-dependent pectinase and the pectin extracted from citrus was the benefit substrate for PelB-B2. The Km and Vmax of PelB-B2 were 1.64 g/L and 232.56 mol/(L min), respectively. The OR-B2 can be a new resource for pectinase production and the PelB-B2 has potential for industrial application. 7 bacteria were isolated from orange peel, namely OR-B1 to OR-B7 and their pectinase activities were assayed. One pectate lyase belongs to PelB family was cloned from OR-B2 and heterogeneous expressed in E. coli. Purified PelB-B2 was further studied with its properties. Effects of pH, temperature, chemicals, substrate on the enzyme activity were assayed and the enzyme kinetic was also measured.


Assuntos
Bacillus/enzimologia , Pectinas/metabolismo , Poligalacturonase/metabolismo , Bacillus/genética , Bacillus/metabolismo , Citrus/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Concentração de Íons de Hidrogênio , Cinética , Poligalacturonase/biossíntese , Polissacarídeo-Liase/metabolismo , Temperatura
16.
Molecules ; 25(1)2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31906348

RESUMO

The synthesis of bioplastic from marine microbes has a great attendance in the realm of biotechnological applications for sustainable eco-management. This study aims to isolate novel strains of poly-ß-hydroxybutyrate (PHB)-producing bacteria from the mangrove rhizosphere, Red Sea, Saudi Arabia, and to characterize the extracted polymer. The efficient marine bacterial isolates were identified by the phylogenetic analysis of the 16S rRNA genes as Tamlana crocina, Bacillus aquimaris, Erythrobacter aquimaris, and Halomonas halophila. The optimization of PHB accumulation by E. aquimaris was achieved at 120 h, pH 8.0, 35 °C, and 2% NaCl, using glucose and peptone as the best carbon and nitrogen sources at a C:N ratio of 9.2:1. The characterization of the extracted biopolymer by Fourier-transform infrared spectroscopy (FTIR), Nuclear magnetic resonance (NMR), and Gas chromatography-mass spectrometry (GC-MS) proves the presence of hydroxyl, methyl, methylene, methine, and ester carbonyl groups, as well as derivative products of butanoic acid, that confirmed the structure of the polymer as PHB. This is the first report on E. aquimaris as a PHB producer, which promoted the hypothesis that marine rhizospheric bacteria were a new area of research for the production of biopolymers of commercial value.


Assuntos
Biopolímeros/biossíntese , Biopolímeros/química , Hidroxibutiratos/química , Hidroxibutiratos/metabolismo , Poliésteres/química , Poliésteres/metabolismo , Sphingomonadaceae/química , Sphingomonadaceae/metabolismo , Avicennia/microbiologia , Bacillus/química , Bacillus/genética , Bacillus/metabolismo , Biopolímeros/análise , Carbono/química , Carbono/metabolismo , Fermentação , Flavobacteriaceae/química , Flavobacteriaceae/genética , Flavobacteriaceae/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Halomonas/química , Halomonas/genética , Halomonas/metabolismo , Hidroxibutiratos/análise , Espectroscopia de Ressonância Magnética , Nitrogênio/química , Nitrogênio/metabolismo , Filogenia , Poliésteres/análise , RNA Ribossômico 16S/genética , Rizosfera , Salinidade , Arábia Saudita , Água do Mar/microbiologia , Espectroscopia de Infravermelho com Transformada de Fourier , Sphingomonadaceae/genética , Sphingomonadaceae/isolamento & purificação , Temperatura
17.
World J Microbiol Biotechnol ; 36(1): 16, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31897642

RESUMO

Earthworms are used as an alternative protein source in aquaculture. These organisms serve as an ideal and favorable site for bacterial growth and activity. Hence, in our present study, we isolated and screened potential probiotic bacteria from African nightcrawler (Eudrilus eugeniae). Among 45 bacterial isolates, four (ANSCI9, BFAR9, RM3, and RM10) were selected based on their hydrophobicity, hydrolytic enzyme production, pH and fish bile tolerance, aggregation, and antimicrobial properties. The selected isolates showed good hydrophobicity (≥ 30%) and enzyme production (≥ 10 mm clearing zones), tolerance to pH and fish bile, and inhibitory properties against pathogenic microorganisms. The isolates were identified as Bacillus sp. RM3 (MH919306), Bacillus sp. RM10 (MH919308), Bacillus sp. ANSCI9 (MH919310) and Bacillus sp. BFAR9 (MH919302). These isolates were individually incorporated in the diets of Nile tilapia (Oreochromis niloticus) fingerlings for 14 days to assess their biosafety. The results showed that the survival rates in all treated groups (98.75 ± 2.5 to 100.00 ± 0.0%) were not significantly different (P < 0.05) from the control group (commercial diet) (96.25 ± 2.5%), suggesting that isolates have no adverse effect on the host. This study revealed the presence of potential probiotic microorganisms in E. eugeniae that are beneficial to the aquaculture industry.


Assuntos
Bacillus/classificação , Ciclídeos/crescimento & desenvolvimento , Oligoquetos/microbiologia , Animais , Aquicultura , Bacillus/genética , Bacillus/isolamento & purificação , Bile/microbiologia , Concentração de Íons de Hidrogênio , Hidrólise , Interações Hidrofóbicas e Hidrofílicas , Filogenia , Probióticos/farmacologia
18.
Recent Pat Biotechnol ; 14(1): 5-15, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31333132

RESUMO

BACKGROUND: Xylanases of thermophilic origin are more robust and stable and hence more suitable for industrial applications. The aim of the research was to develop a patent using a robust mutant exhibiting enhanced xylanase activity. The strain (Bacillus aestuarii SC-2014) subjected to mutagenesis is thermophilic in origin and hence it is envisioned that the enhancement of its catalytic potential will enhance its industrial applicability. OBJECTIVE: The main aim was to develop a stable and vigorous mutant having higher xylanase activity and improved thermostability. METHODS: The bacterial strain isolated from the Tattapani hot springs of Himachal Pradesh (India) was mutagenized by single separate exposure of Ethyl methane sulphonate (EMS) and N-methyl N-nitro N-nitrosoguanidine (MNNG). RESULTS: A mutant library was generated and extensive screening led to the identification of the most potent mutant strain selected and designated as Bacillus sp. SC-2014 EMS200 (MTCC number 25046) which displayed not only enhanced xylanase activity and thermo stability but also appreciable genetic stability. This strain displayed a 3-fold increase in enzyme activity and simultaneously, a significant reduction in fermentation time from 72 h to 48 h was also observed. The xylanase gene from wild and mutant strain was cloned, sequenced and subjected to molecular docking. Two mutations H121D and S123T were present inside the binding pocket. CONCLUSION: Mutation H121D made the binding pocket more acidic and charged, thus enhancing the xylanase activity for mutant protein. Mutations also resulted in charged amino acids (Y99K and H121D) which were identified as a probable cause for enhancing the thermostability of mutant protein.


Assuntos
Proteínas de Bactérias , Endo-1,4-beta-Xilanases , Engenharia de Proteínas/métodos , Bacillus/enzimologia , Bacillus/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sítios de Ligação/genética , Endo-1,4-beta-Xilanases/química , Endo-1,4-beta-Xilanases/genética , Endo-1,4-beta-Xilanases/metabolismo , Estabilidade Enzimática , Fontes Termais/microbiologia , Temperatura Alta , Simulação de Acoplamento Molecular , Mutação
19.
J Microbiol Biotechnol ; 30(3): 404-416, 2020 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-31693829

RESUMO

Bacteria that are resistant to high temperatures and alkaline environments are essential for the biological repair of damaged concrete. Alkaliphilic and halotolerant Bacillus sp. AK13 was isolated from the rhizosphere of Miscanthus sacchariflorus. Unlike other tested Bacillus species, the AK13 strain grows at pH 13 and withstands 11% (w/v) NaCl. Growth of the AK13 strain at elevated pH without urea promoted calcium carbonate (CaCO3) formation. Irregular vateritelike CaCO3 minerals that were tightly attached to cells were observed using field-emission scanning electron microscopy. Energy-dispersive X-ray spectrometry, confocal laser scanning microscopy, and X-ray diffraction analyses confirmed the presence of CaCO3 around the cell. Isotope ration mass spectrometry analysis confirmed that the majority of CO32- ions in the CaCO3 were produced by cellular respiration rather than being derived from atmospheric carbon dioxide. The minerals produced from calcium acetate-added growth medium formed smaller crystals than those formed in calcium lactate-added medium. Strain AK13 appears to heal cracks on mortar specimens when applied as a pelletized spore powder. Alkaliphilic Bacillus sp. AK13 is a promising candidate for self-healing agents in concrete.


Assuntos
Bacillus/genética , Carbonato de Cálcio/farmacologia , Genoma Bacteriano , Álcalis/química , Bacillus/efeitos dos fármacos , Precipitação Química , Filogenia
20.
Can J Microbiol ; 66(2): 144-160, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31714812

RESUMO

Growth and productivity of rice are negatively affected by soil salinity. However, some salt-tolerant rhizosphere-inhabiting bacteria can improve salt resistance of plants, thereby augmenting plant growth and production. Here, we isolated a total of 53 plant-growth-promoting rhizobacteria (PGPR) from saline and non-saline areas in Bangladesh where electrical conductivity was measured as >7.45 and <1.80 dS/m, respectively. Bacteria isolated from saline areas were able to grow in a salt concentration of up to 2.60 mol/L, contrary to the isolates collected from non-saline areas that did not survive beyond 854 mmol/L. Among the salt-tolerant isolates, Bacillus aryabhattai, Achromobacter denitrificans, and Ochrobactrum intermedium, identified by comparing respective sequences of 16S rRNA using the NCBI GenBank, exhibited a higher amount of atmospheric nitrogen fixation, phosphate solubilization, and indoleacetic acid production at 200 mmol/L salt stress. Salt-tolerant isolates exhibited greater resistance to heavy metals and antibiotics, which could be due to the production of an exopolysaccharide layer outside the cell surface. Oryza sativa L. fertilized with B. aryabhattai MS3 and grown under 200 mmol/L salt stress was found to be favoured by enhanced expression of a set of at least four salt-responsive plant genes: BZ8, SOS1, GIG, and NHX1. Fertilization of rice with osmoprotectant-producing PGPR, therefore, could be a climate-change-preparedness strategy for coastal agriculture.


Assuntos
Achromobacter denitrificans/fisiologia , Bacillus/fisiologia , Ácidos Indolacéticos/metabolismo , Ochrobactrum/fisiologia , Oryza/microbiologia , Achromobacter denitrificans/genética , Achromobacter denitrificans/isolamento & purificação , Bacillus/genética , Bacillus/isolamento & purificação , Bangladesh , Fixação de Nitrogênio , Ochrobactrum/genética , Ochrobactrum/isolamento & purificação , Oryza/fisiologia , Fosfatos/metabolismo , RNA Ribossômico 16S/genética , Rizosfera , Salinidade , Estresse Salino , Tolerância ao Sal , Solo/química , Microbiologia do Solo
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