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1.
Ecotoxicol Environ Saf ; 201: 110798, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32526591

RESUMO

Despite constant progress in the understanding of the mechanisms related to the effects of biosurfactants in the bioremediation processes of oily residues, the possibility of antagonist effects on microbial growth and the production in situ of these compounds must be elucidated. The aims of this work were a) to evaluate the effects of the addition of a homemade biosurfactant of Bacillus methylotrophicus on the microbial count in soil in order to determine the possibility of inhibitory effects, and b) to accomplish biostimulation using media prepared with whey and bioaugmentation with B. methylotrophicus, analyzing the effects on the bioremediation of diesel oil and evidencing the in situ production of biosurfactants through effects on surface tension. The homemade bacterial biosurfactant did not present inhibitory effects acting as a biostimulant until 4000 mg biosurfactant/kg of soil. The biostimulation and bioaugmentation presented similar better results (p > 0.05) with the degradation of oil (~60%) than natural attenuation due to the low quantities of biostimulants added. For bioaugmentated and biostimulated soils, a decrease of surface tension between 30 and 60 days was observed, indicating the production of tensoactives in the soil, which was not observed in natural attenuation or a control treatment.


Assuntos
Bacillus/efeitos dos fármacos , Argila/química , Petróleo/análise , Poluentes do Solo/análise , Solo/química , Tensoativos/farmacologia , Bacillus/crescimento & desenvolvimento , Bacillus/metabolismo , Biodegradação Ambiental , Petróleo/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Tensoativos/química
2.
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
3.
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
4.
Ecotoxicol Environ Saf ; 194: 110374, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32120174

RESUMO

Halophytes play an important role in the bioremediation of saline soils. Increased evidence has revealed that plant growth-promoting rhizobacteria (PGPR) have colonized the halophytic rhizosphere, and they have evolved the capacity to reduce salt stress damage to the host. However, the mechanism by which halophytes attract and recruit beneficial PGPR has rarely been reported. This study reports the interaction between the halophyte Limonium sinense and its rhizosphere PGPR strain Bacillus flexus KLBMP 4941, as well as the mechanism by which KLBMP 4941 promotes host plant growth under salt stress. After salt stress treatment, we collected the root exudates (REs) of L. sinense and found that the REs could promote the growth and chemotaxis of the bacterium KLBMP 4941. In addition, the components of the REs under salt stress were analyzed, and some organic acids (2-methylbutyric acid, stearic acid, palmitic acid, palmitoleic acid, and oleic acid) were detected as the major components. Further assessment showed that each of these components had positive effects on the growth, motility, chemotaxis, and root colonization of strain KLBMP 4941. Further pot experiments revealed the potential PGP mechanisms induced by strain KLBMP 4941 on the host plant under salt stress. Inoculation with KLBMP 4941 promoted the accumulation of chlorophyll to enhance photosynthesis, increased osmotic regulator contents, enhanced flavonoid and antioxidant enzymes, and regulated Na+/K+ homeostasis to help the host ameliorate salinity stress damage. Our findings indicate that the halophyte L. sinense can attract and recruit beneficial rhizosphere bacteria by REs under salt stress, and the recruited B. flexus KLBMP 4941 elicited PGP effects under salinity stress through complex plant physiological regulatory mechanisms. This study provides a foundation for the enhancement of the rhizosphere colonization ability of the PGP strain KLBMP 4941, which shows potential applications in phytoremediation of saline soils.


Assuntos
Bacillus/fisiologia , Plumbaginaceae/fisiologia , Microbiologia do Solo , Bacillus/crescimento & desenvolvimento , Bactérias , Clorofila , Desenvolvimento Vegetal , Exsudatos de Plantas , Raízes de Plantas/crescimento & desenvolvimento , Rizosfera , Estresse Salino , Plantas Tolerantes a Sal/microbiologia , Solo
5.
Artigo em Inglês | MEDLINE | ID: mdl-32107954

RESUMO

Microorganisms with efficient organic matter degradation ability are essential for organic waste treatment. In this study, a thermophilic bacterium, Bacillus thermoliquefaciens, was identified to have excellent cellulase, amylase, and protease activity, and provided efficient degradation of food waste. This is the first report on the organic matter degradation potential of B. thermoliquefaciens. Using a "one-variable-at-a-time" approach and response surface methodology, the optimal culture conditions for B. thermoliquefaciens were determined to be a 5% inoculation level, 50 °C culture temperature, 25 mL filling volumes in 250 mL flasks, and 180 rpm shaking for 24 h. The optimized medium was formulated as 1 g Na2HPO4, 1 g KH2PO4, 0.05 g MgSO4, 3 g NaCl, 0.05 g CaCl2, 11.44 g wheat bran powder, 4.92 g soybean meal, and 1 L distilled water at pH 7.12. The maximum biomass attained was 1.57 ± 0.153 × 109 CFU/mL. The cost of this medium was 4.18 times less than that before optimization. This promising result lays a foundation for future industrial application of this bacterium to the degradation of organic waste.


Assuntos
Bacillus/crescimento & desenvolvimento , Meios de Cultura/química , Alimentos , Eliminação de Resíduos/métodos , Resíduos Sólidos , Bacillus/metabolismo , Biodegradação Ambiental , Biomassa , Análise Custo-Benefício , Concentração de Íons de Hidrogênio , Temperatura
6.
Appl Biochem Biotechnol ; 190(2): 391-409, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31363982

RESUMO

Microorganisms that survive in the high salt environment have been shown to be a potential source for metabolites with pharmaceutical importance. In the present study, we have investigated the effect of 5 and 10% (w/v) NaCl on growth, biochemical changes, and metabolite production in seven moderately halophilic bacteria isolated from the salterns/mangrove area of South India. Metabolite production by Bacillus VITPS3 increased by 3.18-fold in the presence of 10% (w/v) NaCl concentration. Total phenolic and flavonoid content increased in Bacillus VITPS5 (11.3-fold) and Planococcus maritimus VITP21 (5.99-fold) whereas ß-carotene content was less at higher NaCl concentrations. VITP21 and VITPS5, in response to NaCl, produced metabolites with higher (6.72- and 4.91-fold) DPPH and ABTS radical scavenging activity. UV/visible spectrophotometry of the extracts confirmed the presence of flavonoids, phenolics, and related compounds. 1H-NMR spectra indicated substantial changes in the metabolite production in response to salt concentration. Principal component analysis (PCA) revealed that VITP21 extracts exhibited the highest antioxidant activity compared with other extracts. The present study presents the first report on the comparative analysis of pigment production by moderate halophilic bacteria, in response to the effect of salt and their relation to radical scavenging property.


Assuntos
Antioxidantes/farmacologia , Bacillus/efeitos dos fármacos , Pigmentos Biológicos/biossíntese , Planococcus (Bactéria)/efeitos dos fármacos , Cloreto de Sódio/farmacologia , Bacillus/crescimento & desenvolvimento , Bacillus/metabolismo , Compostos de Bifenilo/metabolismo , Depuradores de Radicais Livres/farmacologia , Picratos/metabolismo , Planococcus (Bactéria)/crescimento & desenvolvimento , Planococcus (Bactéria)/metabolismo
7.
Appl Biochem Biotechnol ; 190(3): 1092-1105, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31701376

RESUMO

Agro-industrial wastes are excellent sources for solid-state culture to produce spores of microorganisms, whereas microbial co-cultivation is not fully exploited in solid-state culture. In this work, the co-cultivation of different strains of Bacillus subtilis, and three microbes of B. subtilis, Bacillus mucilaginosus, and Paecilomyces lilacinus was studied using a solid medium only composed of water and tobacco waste residue after extraction of nicotine and solanesol. The influences of matrix thickness, moister, temperature, and ratio of three microbes in seed on the cell growth and spore formation were studied. The maximum viable cells and spores of each microbe reached 1013 cfu/g when cultured alone at 30 °C in a medium containing 58.3% moisture. Co-cultivation of microbes stimulated cell growth and maximum viable cells of each microbe reached 1014 cfu/g, while spore production was inhibited and decreased to 1011 cfu/g. With decreasing amount of P. lilacinus in seed, total amount of spores was increased. When the seed with a ratio of 6:3:1 for B. mucilaginosus, B. subtilis, and P. lilacinus was inoculated, the total amount of spores reached 4.14 × 1012 cfu/g and the ratio was 1.7:0.7:1. These results indicate the potential of solid-state cultivation in the high production of spores from tobacco waste residue at low cost.


Assuntos
Bacillus subtilis/crescimento & desenvolvimento , Bacillus/crescimento & desenvolvimento , Resíduos Industriais , Paecilomyces/metabolismo , Tabaco , Meios de Cultura , Fertilizantes , Esporos Bacterianos
8.
J Microbiol Biotechnol ; 29(12): 1982-1992, 2019 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-31650771

RESUMO

The alkaliphilic, calcium carbonate precipitating Bacillus sp. strain AK13 can be utilized in concrete for self-repairing. A statistical experimental design was used to develop an economical medium for its mass cultivation and sporulation. Two types of screening experiment were first conducted to identify substrates that promote the growth of the AK13 strain: the first followed a one-factor-at-a-time factorial design and the second a two-level full factorial design. Based on these screening experiments, barley malt powder and mixed grain powder were identified as the substrates that most effectively promoted the growth of the AK13 strain from a range of 21 agricultural products and by-products. A quadratic statistical model was then constructed using a central composite design and the concentration of the two substrates was optimized. The estimated growth and sporulation of Bacillus sp. strain AK13 in the proposed medium were 3.08 ± 0.38 × 108 and 1.25 ± 0.12 × 108 CFU/ml, respectively, which meant that the proposed low-cost medium was approximately 45 times more effective than the commercial medium in terms of the number of cultivatable bacteria per unit price. The spores were then powdered via a spray-drying process to produce a spore powder with a spore count of 2.0 ± 0.7 × 109 CFU/g. The AK13 spore powder was mixed with cement paste, yeast extract, calcium lactate, and water. The yeast extract and calcium lactate generated the highest CFU/ml for AK13 at a 0.4:0.4 ratio compared to 0.4:0.25 (the original ratio of the B4 medium) and 0.4:0.8. Twenty-eight days after the spores were mixed into the mortar, the number of vegetative cells and spores of the AK13 strain had reached 106 CFU/g within the mortar. Cracks in the mortar under 0.29 mm were healed in 14 days. Calcium carbonate precipitation was observed on the crack surface. The mortar containing the spore powder was thus concluded to be effective in terms of healing micro-cracks.


Assuntos
Bacillus/crescimento & desenvolvimento , Carbonato de Cálcio/química , Técnicas de Cultura de Células/economia , Meios de Cultura/química , Meios de Cultura/economia , Bacillus/metabolismo , Compostos de Cálcio , Contagem de Colônia Microbiana , Materiais de Construção/microbiologia , Custos e Análise de Custo , Dessecação , Lactatos , Esporos Bacterianos/crescimento & desenvolvimento , Água
9.
Appl Microbiol Biotechnol ; 103(19): 7971-7982, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31486874

RESUMO

A nitrogen-starving isolation strategy was developed for the first time to screen bacteria with high calcium-precipitating activity (CPA) for bioremediation of damage in porous media. Meanwhile, a novel mini-tube method based on the detection of insoluble Ca2+ was established to evaluate the CPA of the isolates. A low-nitrogen-demanding strain B6, identified as Bacillus sp., was screened to exhibit the highest CPA (55 mM insoluble Ca2+). Furthermore, the effects of environmental factors and nutrient availability on B6-induced calcium precipitation were evaluated. The results show that nitrate and starch are the best nitrogen source and carbon source with optimal concentration being 4 and 2 g L-1, respectively. The suitable pH range for B6 to precipitate calcium is from 8.5 to 10.5. B6 can maintain the highest CPA at an initial spore concentration of 1.0 × 108 spores·mL-1. The optimal CaO2 dosage is 10 g L-1. Finally, the calcite precipitation is confirmed by ESEM, EDS, and XRD analysis.


Assuntos
Bacillus/metabolismo , Carbonato de Cálcio/metabolismo , Precipitação Química , Nitratos/metabolismo , Antiácidos , Bacillus/crescimento & desenvolvimento , Carbono/metabolismo , Meios de Cultura/química , Concentração de Íons de Hidrogênio , Nitrogênio/metabolismo , Amido/metabolismo
10.
Biosens Bioelectron ; 143: 111628, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31476599

RESUMO

A combined calorimetric gas- and spore-based biosensor array is presented in this work to monitor and evaluate the sterilization efficacy of gaseous hydrogen peroxide in aseptic filling machines. H2O2 has been successfully measured under industrial conditions. Furthermore, the effect of H2O2 on three different spore strains , namely Bacillus atrophaeus, Bacillus subtilis and Geobacillus stearothermophilus, has been investigated by means of SEM, AFM and impedimetric measurements. In addition, the sterilization efficacy of a spore-based biosensor and the functioning principle are addressed and discussed: the sensor array is convenient to be used in aseptic food industry to guarantee sterile packages.


Assuntos
Técnicas Biossensoriais , Calorimetria , Peróxido de Hidrogênio/isolamento & purificação , Esporos Bacterianos/efeitos dos fármacos , Bacillus/efeitos dos fármacos , Bacillus/crescimento & desenvolvimento , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/crescimento & desenvolvimento , Desinfetantes/química , Desinfetantes/isolamento & purificação , Gases/química , Gases/isolamento & purificação , Geobacillus stearothermophilus/efeitos dos fármacos , Geobacillus stearothermophilus/crescimento & desenvolvimento , Humanos , Peróxido de Hidrogênio/farmacologia , Infertilidade , Esporos Bacterianos/crescimento & desenvolvimento , Esterilização
11.
Int J Food Microbiol ; 307: 108288, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31421399

RESUMO

Even though spore-forming bacteria have been mainly linked to spoilage or foodborne pathogens vehiculated through foods, some strains of Bacillus can potentially present probiotic properties. The advantage of incorporating probiotic Bacillus strains in foods relies mainly on the fact that these microorganisms present high resistance to harsh processing conditions. "Requeijão cremoso" is a type of processed cheese highly appreciated in Brazil. During processing, this product is submitted to several harsh conditions (heating at 90 °C, for instance), leading to the inactivation of probiotic bacteria belonging to Lactobacillus and Bifidobacterium genera. That fact has precluded the development of probiotic "requeijão cremoso" products; however, probiotic Bacillus strains may comprise a promising alternative to overcome the low resistance of traditional probiotics to food processing. The objective of this study was to evaluate the behavior of different Bacillus strains with claimed probiotic properties throughout processed cheese ("requeijão cremoso") manufacturing. A total of five different Bacillus strains with claimed probiotic properties (B. coagulans MTCC 5856, B. coagulans GBI-30 6086, B. subtilis PXN 21, B. subtilis PB6, and B. flexus HK1) were individually inoculated at different stages of manufacture - curd pasteurization, coagulation, and fusion - of "requeijão cremoso" and their survival in each of these stages was determined. The survival of B. coagulans GBI-30 6086 was further assessed throughout "requeijão cremoso" production and shelf life (45 days at 6 °C). Besides, the chemical composition, level of proteolysis, and fatty acid profile of the treatments during shelf life were evaluated. The fusion stage was found as the most appropriate for the addition of B. coagulans GBI-30 6086, which allows the production of probiotic "requeijão cremoso" and facilitates the technological process while preventing the occurrence of final product recontamination.


Assuntos
Bacillus/fisiologia , Queijo/microbiologia , Manipulação de Alimentos , Armazenamento de Alimentos , Probióticos , Bacillus/classificação , Bacillus/crescimento & desenvolvimento , Bacillus/metabolismo , Bifidobacterium/crescimento & desenvolvimento , Bifidobacterium/metabolismo , Bifidobacterium/fisiologia , Brasil , Queijo/análise , Lactobacillus/crescimento & desenvolvimento , Lactobacillus/metabolismo , Lactobacillus/fisiologia , Especificidade da Espécie , Esporos Bacterianos/crescimento & desenvolvimento , Temperatura
12.
Food Microbiol ; 84: 103244, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31421772

RESUMO

Today, there is no effective non-thermal method to inactivate unwanted bacterial spores in foods. High-Pressure (HP) process has been shown to act synergistically with moderate heating and the bacteriocin nisin to inactivate spores but the mechanisms have not been elucidated. The purpose of the present work was to investigate in depth the synergy of HP and nisin on various foodborne spore species and to bring new elements of understandings. For this purpose, spores of Bacillus pumilus, B. sporothermodurans, B. licheniformis, B. weihenstephanensis, and Clostridium sp. were suspended in MES buffer, in skim milk or in a liquid medium simulating cooked ham brine and treated by HP at 500 MPa for 10 min at 50 °C or 20 °C. Nisin (20 or 50 IU/mL) was added at three different points during treatment: during HP, during and or in the plating medium of enumeration. In the latter two cases, a high synergy was observed with the inhibition of the spores of Bacillus spp. The evaluation of the germinated fraction of Bacillus spp. spores after HP revealed that this synergy was likely due to the action of nisin on HP-sensitized spores, rather than on HP-germinated spores. Thus, the combination of nisin and HP can lead to Bacillus spp. spore inhibition at 20 °C. And Nisin can act on HP-treated spores, even if they are not germinated. This paper provides new information about the inhibition of spores by the combination of HP and nisin. The high synergy observed at low temperature has not been reported yet and could allow food preservation without the use of any thermal process.


Assuntos
Pressão Atmosférica , Viabilidade Microbiana/efeitos dos fármacos , Nisina/farmacologia , Esporos Bacterianos/efeitos dos fármacos , Bacillus/efeitos dos fármacos , Bacillus/crescimento & desenvolvimento , Clostridium/efeitos dos fármacos , Clostridium/crescimento & desenvolvimento , Conservação de Alimentos , Temperatura Alta
13.
Bioprocess Biosyst Eng ; 42(11): 1819-1828, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31435737

RESUMO

Electrolytic manganese residue (EMR) is a type of industrial solid waste with a high silicon content. The silicon in EMR can be used as an essential nutrient for plant growth, but most of the silicon is found in silicate minerals with very low water solubility, that is, it is inactive silicon and cannot be absorbed and used by plants directly. Thus, developing a highly effective and environmentally friendly process for the activation of silicon in EMR is important both for reusing solid waste and environmental sustainability. The aim of this study was to investigate the desilication of EMR using cultures of Paenibacillus mucilaginosus (PM) and Bacillus circulans (BC). The results showed that the two types of silicate bacteria and a mixed strain of them were all able to extract silicon from EMR with a high efficiency, but the desilication performance of the mixed PM and BC was the best. Fourier transform infrared spectroscopy indicated that silicate bacteria can induce a suitable micro-environment near the EMR particles and release Si into the solution through their metabolism. X-ray diffraction analysis confirmed that layered crystal minerals, such as muscovite and diopside, were more likely to be destroyed by the bacterial action than quartz, which has a frame structure. Scanning electron microscopy-energy dispersive spectrometry proved that the silicate structures were destroyed and that Si in the residue was decreased, indicating the dissolution of silicon under the action of these microorganisms. This study suggests that bioleaching may be a promising method for the activation of silicon in EMR.


Assuntos
Bacillus/crescimento & desenvolvimento , Manganês/metabolismo , Paenibacillus/crescimento & desenvolvimento , Silício/metabolismo , Resíduos Sólidos , Biodegradação Ambiental
14.
Microb Pathog ; 136: 103671, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31437575

RESUMO

Yaks are an aboriginal breed of the Qinghai-Tibet plateau (3000 m), which are highly adaptable to cold and hypoxic environments. It is noticed that hypoxia and hypothermia can induce changes in intestinal microbial structure in animals. Increasing evidences suggested that probiotics supplementation can improve the balance of gut microbiota of animals. However, so far, very few studies have emphasized on the probiotics isolated from yaks in the Qinghai-Tibet Plateau. Therefore, a potential probiotic strain Bacillus velezensis was isolated from yaks. In the present study, a total of 18 Kunming mice (15-18 g) were equally distributed into two groups; control and probiotic treated groups (1 × 109 CFU/day). During the experimental period, all the mice from both groups were given standard normal diet ad libitum. At the end of the experiment, mice were euthanized and the intestines (duodenum, jejunum, ileum, and cecum) were removed for high-throughput sequencing. The results demonstrated that Bacillus velezensis supplementation showed beneficial effects on the gut microbiota of mice. Specifically, Bacillus velezensis supplementation increased the population of Lactobacillus and Ruminococcus in the duodenum, and Candidatus Arthromitus in the jejunum. Additionally, Acinetobacter in the duodenum and Helicobacter in the cecum were decreased after feeding Bacillus velezensis. Altogether, these findings suggested that Bacillus velezensis isolated from Tibetan yaks can improve gut microbiota of mice.


Assuntos
Bacillus/crescimento & desenvolvimento , Dieta/métodos , Microbioma Gastrointestinal , Probióticos/administração & dosagem , Animais , Bacillus/isolamento & purificação , Bovinos/microbiologia , Ceco/microbiologia , Duodeno/microbiologia , Íleo/microbiologia , Jejuno/microbiologia , Metagenômica , Camundongos , Tibet
15.
Mol Microbiol ; 112(5): 1552-1563, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31461569

RESUMO

OLE RNAs represent an unusual class of bacterial noncoding RNAs common in Gram-positive anaerobes. The OLE RNA of the alkaliphile Bacillus halodurans is highly expressed and naturally interacts with at least two RNA-binding proteins called OapA and OapB. The phenotypes of the corresponding knockouts include growth inhibition when exposed to ethanol or other short-chain alcohols or when incubated at modestly reduced temperatures (e.g. 20°C). Intriguingly, the OapA 'PM1' mutant, which carries two amino acid changes to a highly conserved region, yields a dominant-negative phenotype that causes more severe growth defects under these same stress conditions. Herein, we report that the PM1 strain also exhibits extreme sensitivity to elevated Mg2+ concentrations, beginning as low as 2 mM. Suppressor mutants predominantly map to genes for aconitate hydratase and isocitrate dehydrogenase, which are expected to alter cellular citrate concentrations. Citrate reduces the severity of the Mg2+ toxicity phenotype, but neither the genomic mutations nor the addition of citrate to the medium overcomes ethanol toxicity or temperature sensitivity. These findings reveal that OLE RNA and its protein partners are involved in biochemical responses under several stress conditions, wherein the unusual sensitivity to Mg2+ can be independently suppressed by specific genomic mutations.


Assuntos
Antibacterianos/farmacologia , Bacillus/crescimento & desenvolvimento , Magnésio/farmacologia , RNA não Traduzido/metabolismo , Ribonucleoproteínas/metabolismo , Aconitato Hidratase/genética , Bacillus/genética , Ácido Cítrico/metabolismo , Etanol/farmacologia , Isocitrato Desidrogenase/genética , RNA não Traduzido/genética , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Ribonucleoproteínas/genética
16.
Ecotoxicol Environ Saf ; 183: 109466, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31408821

RESUMO

The potential of plant growth regulating microorganisms present in the soil can be explored towards the purpose of identifying salt tolerant strategies and crop cultivars. Current study was designed to elucidate the capabilities of salt stress tolerant plant growth promoting rhizobacteria (PGPR) Bacillus siamensis (PM13), Bacillus sp. (PM15) and Bacillus methylotrophicus (PM19) in undermining the effects of salt stress on wheat seedling. Strains were characterized for their IAA (81-113 µM/ml), ACC-deaminase (0.68-0.95 µM/mg protein/h) and exopolysaccharide (EPS) (0.62-0.97 mg/ml) producing activity both under normal and NaCl stressed conditions. Effects of bacterial inoculation on germination and seedling growth of wheat variety Pakistan-13 was observed under induced salinity stress levels (0, 4, 8, 16 dS/m). All the morpho-physiological characteristics of wheat seedlings were affected drastically by the NaCl stress and the growth parameters expressed a negative relationship with increased NaCl levels. PGPR application had a very positive influence on germination rate of wheat seedlings, root and shoot length, photosynthetic pigments etc. Elongated roots and enhanced vegetative shoot growth as well as seedling's fresh and dry weights were highest in plants treated with B. methylotrophicus PM19. Sequestration of Na+ ion by EPS production and degradation of exuded ACC into a-ketobutyrate and ammonia by ACCD bacteria efficiently reduced the impact of salinity stress on wheat growth. Current findings suggested that the used PGPR strains are potential candidates for improving crop growth in salt stressed agricultural systems. However further research validation would be necessary before large scale/field application.


Assuntos
Bacillus/crescimento & desenvolvimento , Carbono-Carbono Liases/metabolismo , Germinação , Polissacarídeos Bacterianos/metabolismo , Plantas Tolerantes a Sal/crescimento & desenvolvimento , Triticum/crescimento & desenvolvimento , Bacillus/metabolismo , Paquistão , Salinidade , Plantas Tolerantes a Sal/efeitos dos fármacos , Plantas Tolerantes a Sal/microbiologia , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Microbiologia do Solo , Triticum/efeitos dos fármacos , Triticum/microbiologia
17.
J Basic Microbiol ; 59(10): 979-991, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31469183

RESUMO

This study investigates the effect of metals (cadmium, lead, mercury, and tellurium) and organic pollutants (benzene, diesel, lindane, and xylene) on a dinoflagellate-Prorocentrum sigmoides Böhm-and its associated culturable bacteria. Two bacterial cultures (Bacillus subtilis strain PD005 and B. xiamensis strain PD006) were isolated from P. sigmoides and characterized by scanning electron microscopy, 16S ribosomal RNA sequencing, biochemical analyses, and growth curve studies. This study points to a mutualistic relationship between P. sigmoides and its associated Bacillus isolates. P. sigmoides enhanced the growth of its associated Bacillus spp., through the secretion of extracellular exudates. In return, both Bacillus isolates contributed to the resistance of P. sigmoides to metals and organic pollutants. P. sigmoides and both Bacillus isolates exhibited concentration-dependent responses to metals and organic pollutants. An intriguing feature was the similar response of P. sigmoides and its associated Bacillus isolates to mercury and cadmium, indicating a co-selection of mercury and cadmium resistance. This provides support to the "dinoflagellate host-phycosphere bacteria" behaving as a single functional unit. However, the sensitivity profiles of P. sigmoides and its associated Bacillus isolates are different with respect to metals versus organic pollutants. These aspects need to be addressed in future studies to unravel the effect of metal and organic pollutants on dinoflagellates, an important component of the phytoplankton community, and to discern the influence of associated "phycosphere" bacteria on the response of dinoflagellates to pollutants.


Assuntos
Bacillus/efeitos dos fármacos , Dinoflagelados/efeitos dos fármacos , Dinoflagelados/microbiologia , Hidrocarbonetos/farmacologia , Metais/farmacologia , Poluentes Químicos da Água/farmacologia , Bacillus/genética , Bacillus/crescimento & desenvolvimento , Bacillus/ultraestrutura , Coevolução Biológica , DNA Bacteriano/genética , Dinoflagelados/metabolismo , Resistência a Medicamentos , Microscopia Eletrônica de Varredura , RNA Ribossômico 16S/genética , Simbiose
18.
Biotechnol Appl Biochem ; 66(5): 900-910, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31400027

RESUMO

Synergistic effects of metallic nanoparticles (NPs) with commonly used antibiotics have encouraged the exploration of novel biological entities, including bacteria and weed plants. The present study for the first time reports the capability of an extracellular fraction of Bacillus sp. isolated from effluents of a glass-manufacturing unit to biosynthesis silver nanoparticles (AgNPs) without hazardous materials. Besides, the biosynthesis of AgNPs using an aqueous extract of herbaceous weed plant (Amaranthus sp.), as a low-cost natural source, has been addressed in this study. Our findings confirmed the fabrication of microbial and plant-sourced AgNPs, being thoroughly characterized by UV-vis, transmission electron microscopy, X-ray diffraction, dynamic light scattering, energy dispersive X-ray spectroscopy, and zeta potential measurements. Further, biological activities of the plant- and bacterium-derived AgNPs were investigated against several pathogenic bacteria, in combination with streptomycin. The antibacterial effectiveness of the antibiotic coated with 400 µg/disk of AgNPs increased over 50% toward all the pathogenic bacteria. The data presented here demonstrate that both industrial wastewater-adapted Bacillus sp. and wild-growing Amaranthus sp. are efficient natural sources with excellent capabilities for creating biologically active AgNPs, which would be of considerable interest for circumventing bacterial resistance to current antibiotics.


Assuntos
Amaranthus/efeitos dos fármacos , Antibacterianos/biossíntese , Bacillus/efeitos dos fármacos , Vidro , Resíduos Industriais , Nanopartículas Metálicas/química , Prata/farmacologia , Amaranthus/crescimento & desenvolvimento , Antibacterianos/química , Antibacterianos/farmacologia , Bacillus/crescimento & desenvolvimento , Indústrias , Testes de Sensibilidade Microbiana , Prata/química , Prata/metabolismo
19.
Int J Food Microbiol ; 305: 108245, 2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31295678

RESUMO

This study aimed to evaluate the performance of Hicrome Bacillus™ agar for isolation and rapid identification of the aerobic spore-forming bacteria most frequently found in honey samples. A collection of 197 bacterial isolates of Bacillus, Brevibacillus, Lysinibacillus, Paenibacillus, and Rummeliibacillus belonging to different species that have been reported in honey were screened for their abilities to grow and for their colony colors and medium appearance in HiCrome Bacillus agar. Also, 21 strains from culture collections were used for comparison and quality controls. A flowchart utilizing a combination of colony and media characteristics in the chromogenic medium and a set of simple biochemical and morphological tests were elaborated for quick presumptive identification. A procedure for direct isolation from honey samples was developed. In conclusion, HiCrome Bacillus agar in combination with simple microbiological tests was highly useful for rapid and reliable identification of most Bacillus, Brevibacillus, Lysinibacillus and Paenibacillus species commonly found in honey samples facilitating isolation from polymicrobial honey.


Assuntos
Bacillaceae/isolamento & purificação , Bacillus/isolamento & purificação , Contagem de Colônia Microbiana/métodos , Mel/microbiologia , Bacillaceae/classificação , Bacillaceae/genética , Bacillaceae/crescimento & desenvolvimento , Bacillus/classificação , Bacillus/genética , Bacillus/crescimento & desenvolvimento , Contagem de Colônia Microbiana/instrumentação , Microbiologia de Alimentos
20.
Gene ; 713: 143971, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31299361

RESUMO

An in silico genome analysis of the probiotic Bacillus strain FTC01 was performed. The draft genome comprises 3.9 Mb, with a G + C content of 46.6% and a total of 3941 coding sequences. The species of strain FTC01 was defined as B. velezensis during GenBank genome annotation, following the current nomenclature. Eight gene clusters involved in the synthesis of non-ribosomal lipopeptides, polyketides and bacilysin were found, as well as part of the gene cluster involved in the synthesis of cyclic lipopeptide locillomycin. The production of lipopeptides surfactin and iturin by strain FTC01 was confirmed. In addition, a gene encoding a peptidylprolyl isomerase, involved in bacterial adhesion to the host tissue, beyond twelve genes responsible for acid tolerance and several hydrolase genes were found. These characteristics may help in host colonization and maintenance and may account for the probiotic properties observed for strain FTC01.


Assuntos
Bacillus/genética , Bacillus/metabolismo , Proteínas de Bactérias/genética , Genoma Bacteriano , Metaboloma , Probióticos/metabolismo , Bacillus/crescimento & desenvolvimento , DNA Bacteriano/análise , Filogenia , Análise de Sequência de DNA/métodos
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