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1.
Toxicon ; 180: 43-48, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32298663

RESUMO

Zearalenone, an oestogenic mycotoxin produced by Fusarium sp., occurs naturally in agricultural commodities. Economic losses and health concerns associated to mycotoxins has attracted research interest towards exploring novel approaches to detoxify mycotoxin-contaminated food and feed. The aim of the present work was to study the ability of 11 aflatoxin-degrading Bacillus strains to degrade ZEA. In addition, a qualitative assessment of protease, amylase and cellulase activity of the studied Bacillus strains was made. All strains were able to degrade 58-96.9% ZEA after 72 h. Toxicity towards Artemia salina was significantly reduced (P < 0.0001). Degradation extracts fluorescence decreased 50% indicating a probable cleavage of the lactone ring. Strains RC1A, RC3A and RC6A showed a remarkable enzymatic activity, showing potential to be used as feed additives.


Assuntos
Aflatoxinas/metabolismo , Amilases/metabolismo , Bacillus/metabolismo , Celulases/metabolismo , Peptídeo Hidrolases/metabolismo , Zearalenona/metabolismo , Agricultura , Inativação Metabólica
2.
Microbiol Res ; 236: 126467, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32248049

RESUMO

Strains of Xylella fastidiosa subsp. pauca characterized by a specific genotype, the so called sequence type "ST53", have been associated with a severe disease named Olive Quick Decline Syndrome (OQDS). Despite the relevant research efforts devoted to control the disease caused by X. fastidiosa, so far there are no therapeutic means able to cure the infected host plants. As such, the aim of this study was the identification of antagonistic bacteria potentially deployable as bio-control agents against X. fastidiosa. To this end, two approaches were used, i.e. the evaluation of the antagonistic activity of: i) endophytic bacteria isolated from olive trees located in an infected area but showing mild or no symptoms, and ii) Bacillus strains, as they are already known as bio-control agents. Characterization of endophytic bacterial isolates revealed that the majority belonged to different species of the genera Sphingomonas, Methylobacterium, Micrococcus and Curtobacterium. However, when they were tested in vitro against X. fastidiosa ST53 none of them showed antagonistic activity. On the contrary, when strains belonging to different species of the genus Bacillus were included in these tests, remarkable antagonistic activities were recorded. Some B. velezensis strains also produced culture filtrates with inhibitory activity against X. fastidiosa ST53. Taking also into account that two of these B. velezensis strains (namely strains D747 and QST713) are already registered and commercially available as bio-control agents, our results pave the way for further studies aimed at the development of a sustainable bio-control strategy of the OQDS.


Assuntos
Antibiose , Bacillus , Endófitos/isolamento & purificação , Olea/microbiologia , Xylella , Bacillus/metabolismo , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Agentes de Controle Biológico/farmacologia , DNA Bacteriano/genética , Endófitos/genética , Endófitos/metabolismo , Patologia Molecular , Doenças das Plantas/microbiologia , Doenças das Plantas/terapia , Xylella/patogenicidade
3.
PLoS One ; 15(2): e0228936, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32084150

RESUMO

A total of fifteen potential methyl t-butyl ether (MtBE)-degrading bacterial strains were isolated from contaminated soil. They have been identified as belonging to the genera Bacillus, Pseudomonas, Kocuria, Janibacter, Starkeya, Bosea, Mycolicibacterium, and Rhodovarius. Bacillus aryabhattai R1B, S. novella R8b, and M. mucogenicum R8i were able to grow using MtBE as carbon source, exhibiting different growth behavior and contaminant degradation ability. Their biocontrol ability was tested against various fungal pathogens. Both S. novella R8b and B. aryabhattai were effective in reducing the development of necrotic areas on leaves within 48 hours from Botritys cinerea and Alternaria alternata inoculation. Whereas, M. mucogenicum effectively controlled B. cinerea after 72 hours. Similar results were achieved using Pythium ultimum, in which the application of isolated bacteria increased seed germination. Only M. mucogenicum elicited tomato plants resistance against B. cinerea. This is the first report describing the occurrence of bioremediation and biocontrol activities in M. mucogenicum, B. aryabhattai and S. novella species. The production of maculosin and its antibiotic activity against Rhizoctonia solani has been reported for first time from S. novella. Our results highlight the importance of multidisciplinary approaches to achieve a consistent selection of bacterial strains useful for plant protection and bioremediation purposes.


Assuntos
Bactérias/isolamento & purificação , Biodegradação Ambiental , Éteres Metílicos/toxicidade , Alphaproteobacteria/isolamento & purificação , Alphaproteobacteria/metabolismo , Bacillus/isolamento & purificação , Bacillus/metabolismo , Bactérias/metabolismo , Lycopersicon esculentum/microbiologia , Éteres Metílicos/química , Mycobacteriaceae/isolamento & purificação , Mycobacteriaceae/metabolismo , Doenças das Plantas/microbiologia , Rhizoctonia/crescimento & desenvolvimento , Solo , Microbiologia do Solo
4.
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
5.
Prep Biochem Biotechnol ; 50(1): 91-97, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31517567

RESUMO

Xylanases have gained increasing importance due to their diverse applications in the food, paper, and pharmaceutical industries, however, the production of these enzymes currently uses expensive substrates. It has already been estimated that more than 30% of the enzyme production cost originates from the substrate. The present study aimed to optimize the production of extracellular xylanases by the Bacillus sp. TC-DT 13 using solid-state fermentation with agro-industrial residues, with a view at reducing the production cost of these enzymes. All the agro-industrial residues were tested in submerged fermentation to select the best inductor to produce xylanase. Among these residues, wheat bran was selected as the best inducer of xylanase production with 1500 U/mL. Regarding solid-state fermentation, the use of wheat bran as the only fermentation substrate was used and a ratio of 1:4 moisture over a time of 144 hours induced higher amount of xylanase reaching 2943 U/g. The use of carbon and nitrogen sources did not result in the increase in production of xylanolitic enzymes. The use of agro-industrial residues in the solid-state fermentation, besides increasing the production of xylanase, reduces the cost of production and is an environmentally friendly alternative.


Assuntos
Bacillus/enzimologia , Fibras na Dieta/metabolismo , Endo-1,4-beta-Xilanases/metabolismo , Bacillus/metabolismo , Carbono/metabolismo , Fermentação , Microbiologia Industrial/economia , Microbiologia Industrial/métodos , Nitrogênio/metabolismo , Temperatura
6.
J Basic Microbiol ; 60(1): 47-57, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31680284

RESUMO

The present investigation deals with the characterisation of three As-resistant bacteria, Bacillus aryabhattai strain VPS1, Bacillus licheniformis strain VPS6 and Sporosarcina thermotolerans strain VPS7 isolated from the rhizosphere of a contaminated paddy field in Chakdaha, Nadia, West Bengal, India. Two strains, VPS6 and VPS7 showed ureolytic activity, which can be used for microbial-induced calcite precipitation of As as a bioremediation option. However, As reduction and oxidation capacities were not reported in any of these bacteria. A phylogenetic tree of 16S ribosomal RNA gene sequences was constructed for all three bacterial isolates, including different species of As-resistant Bacillus and Sporosarcina. Furthermore, literature survey and genome mining were employed to explore the diversity of As resistance-related proteins, arsenite S-adenosylmethyltransferase (ArsM) and arsenical pump membrane protein (ArsB) among different bacteria, and the phylogenetic relatedness was studied to understand the distribution and evolution of their amino acid sequences. ArsB was predominantly present in a wide variety of bacteria (347 taxa); however, ArsM was reported in comparatively fewer isolates (109 taxa). There were a total of 60 similar taxa that contained both ArsM and ArsB. Both proteins were most abundantly present in phylum Proteobacteria. Overall, this investigation enumerates As-resistant bacteria to understand the As metabolism in the environment, and the phylogenetic analysis of As resistance-related proteins helps in understanding the functional relationship in different bacteria for their role in As mobility in the environment.


Assuntos
Arsenicais/metabolismo , Bactérias/metabolismo , Proteínas de Bactérias/genética , Farmacorresistência Bacteriana/genética , Poluentes do Solo/metabolismo , Bacillus/genética , Bacillus/metabolismo , Bacillus licheniformis/genética , Bacillus licheniformis/metabolismo , Bactérias/classificação , Bactérias/genética , Biodegradação Ambiental , Índia , Filogenia , RNA Ribossômico 16S/genética , Rizosfera , Microbiologia do Solo , Sporosarcina/genética , Sporosarcina/metabolismo , Ureia/metabolismo
7.
Arch Microbiol ; 202(1): 63-75, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31485713

RESUMO

Silver nanoparticles (AgNPs) were synthesized using cell-free filtrates of some mosquitocidal Bacilli. They showed the optical absorption peaks at 386-412 nm. They were polycrystalline spherical, hexagonal, cuboidal, rod and anisotropic shapes as detected by TEM. These nanoparticles were negatively charged with sizes ranging from 15 to 21 nm average diameter as detected by DLS. FTIR spectra showed that the main absorption bands of biomolecules capping AgNPs appeared at average wave numbers of 3435 cm-1 [ν(N-H) of amide A overlapped by ν(O-H)], 1631 cm-1 [(ν(C=O) of amide I], 1396 cm-1 [ν(C-N) of amide I], 2929 cm-1 (aliphatic C-H) and 1040 cm-1 (C-C-O). FTIR spectra confirmed the presence of protein biomolecules in the bacterial filtrate-formed coat covering AgNPs through free amide groups resulting in their stabilization in the aqueous medium. Nitrate reductase activity was found in all tested bacterial filtrates and ranged from 1.66 to 2.51 µmol/ml/min. These findings point to the probable role of nitrate reductase in reducing silver ions to silver nanoparticles and their stabilization. Tested AgNPs were multi-bioactive nanometals and showed mosquitocidal, bactericidal, fungicidal and virucidal activities. In addition, they exhibited highly synergistic mosquitocidal effect to spore toxin complex of mosquitocidal Bacilli at a very low concentration. AgNPs exhibited activities that were not or slightly cytotoxic to MA 104 cell line at tested concentrations. Therefore, they can be applied in the medical field. Finally, this study offered a simple, highly efficient, eco-friendly, economic method for biosynthesis of multi-bioactive AgNPs by some mosquitocidal Bacilli.


Assuntos
Bacillus/fisiologia , Nanopartículas Metálicas/química , Prata/química , Prata/farmacologia , Animais , Antibacterianos/química , Bacillus/enzimologia , Bacillus/metabolismo , Linhagem Celular , Nanopartículas Metálicas/ultraestrutura , Microscopia Eletrônica de Transmissão , Nitrato Redutase/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier
8.
J Microbiol ; 58(2): 131-141, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31872373

RESUMO

Response regulator (RR) is known a protein that mediates cell's response to environmental changes. The effect of RR from extremophiles was still under investigation. In this study, response regulator homologs were mined from NGS data of Antarctic bacteria and overexpressed in Escherichia coli. Sixteen amino acid sequences were annotated corresponding to response regulators related to the two-component regulatory systems; of these, 3 amino acid sequences (DRH632, DRH1601 and DRH577) with high homology were selected. These genes were cloned in pRadGro and expressed in E. coli. The transformant strains were subjected to various abiotic stresses including oxidative, osmotic, thermal stress, and acidic stress. There was found that the robustness of E. coli to abiotic stress was increased in the presence of these response regulator homologs. Especially, recombinant E. coli overexpressing drh632 had the highest survival rate in oxidative, hypothermic, osmotic, and acidic conditions. Recombinant E. coli overexpressing drh1601 showed the highest tolerance level to osmotic stress. These results will be applicable for development of recombinant strains with high tolerance to abiotic stress.


Assuntos
Extremófilos/genética , Regulação Bacteriana da Expressão Gênica , Estresse Oxidativo/genética , Estresse Fisiológico/genética , Regiões Antárticas , Bacillus/genética , Bacillus/metabolismo , Bacillus pumilus/genética , Bacillus pumilus/metabolismo , Proteínas de Bactérias/genética , Clonagem Molecular , Biologia Computacional , Escherichia coli/genética , Escherichia coli/fisiologia , Extremófilos/metabolismo , Genoma Bacteriano , Estresse Oxidativo/fisiologia , Estresse Fisiológico/fisiologia , Transformação Bacteriana
9.
World J Microbiol Biotechnol ; 36(1): 7, 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31845300

RESUMO

Orange juice is a major agricultural product, and oranges are among the most widely sold fresh fruits in several countries. Citrus black spot (CBS), caused by the fungus Phyllosticta citricarpa, affects almost every species of citrus, causing a esthetic depreciation of the fruit and fruit drop, with consequent financial loss for its in natura commercialization. Fungicides are the major control measure for CBS, but have limited efficiency and high cost, and give rise to fungal strains resistant to these products. This work assayed the production of antifungal compounds by Bacillus spp. isolates and tested the potential of two isolates from B. subtilis (ACB-AP3 and ACB-83) for controlling CBS under field conditions with two previously untested orange varieties. A total of 15 isolates produced cell-free, thermostable or volatile compounds effective in suppressing P. citricarpa growth in vitro. It was possible to detect the production of two antibiotics (iturin and surfactin) by B. subtilis ACB-83. Additionally, B. subtilis isolates ACB-AP3 and ACB-83 displayed significant effects in controlling the disease under field conditions.


Assuntos
Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Ascomicetos/efeitos dos fármacos , Bacillus/isolamento & purificação , Bacillus/metabolismo , Citrus/microbiologia , Ascomicetos/crescimento & desenvolvimento , Ascomicetos/patogenicidade , Frutas/microbiologia , Fungicidas Industriais/metabolismo , Fungicidas Industriais/farmacologia , Doenças das Plantas/microbiologia , Esporos Fúngicos
10.
J Agric Food Chem ; 67(49): 13558-13567, 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31738544

RESUMO

Organophosphorus insecticides (OPs) have been widely used to control agricultural pests, which has raised concerns about OP residues in crops and the environment. In this study, we investigated the degradation kinetics and pathways of 8 OPs by Cupriavidus nantongensis X1T and identified the enzyme via gene cloning and in vitro assays. The degradation half-life of methyl parathion, triazophos, and phoxim was only 5, 9, and 43 min, respectively. It was 46 fold faster than that of triazophos by Bacillus sp. TAP-1, a well-studied triazophos-degrader. Strain X1T completely degraded not only chlorpyrifos, methyl parathion, parathion, fenitrothion, triazophos, and phoxim at 50 mg/L within 48 h but also the phenolic metabolites. This was the fastest degradation of OPs by bacterial whole cells reported thus far. The OPs were first hydrolyzed by an OP hydrolase encoded by the opdB gene in strain X1T, followed by further degradation of the metabolites. The crude enzyme maintained a full activity.


Assuntos
Clorpirifos/metabolismo , Cupriavidus/metabolismo , Inseticidas/metabolismo , Bacillus/metabolismo , Biodegradação Ambiental , Clorpirifos/química , Cupriavidus/química , Inseticidas/química , Cinética , Organotiofosfatos/metabolismo , Triazóis/metabolismo
11.
Ecotoxicol Environ Saf ; 186: 109792, 2019 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-31629191

RESUMO

Cr(VI) reduction by microorganisms has been extensively reported, however, the mechanism of Cr(VI) reduction varies among different microorganisms. In this study, a Cr(VI)-reducing bacterium identified as Bacillus sp. was isolated from tannery activated sludge, strain CRB-1 was able to completely reduce 50 mg/L of Cr(VI) within 24 h under aerobic conditions and exhibited considerable Cr(VI) removal efficiency in the pH range from 7.0 to 9.0, temperature 24-42 °C. Cr(VI) reduction assays with resting cells, permeabilized cells, and subcellular fractions suggested that Cr(VI) reduction mainly occurred in the cytoplasm. According to qRT-PCR analysis, a chrA gene and a nitR2 gene were up-regulated under Cr(VI) stress. Heterologous expression of the chrA gene and the nitR2 gene indicated that ChrA was associated with Cr(VI) resistance, while NitR2 was responsible for Cr(VI) reduction. Furthermore, soluble end products were detected. On the basis of FTIR, it was speculated that the formation of soluble end products may be due to the complexation of EPS with Cr(III). Consequently, the Cr(VI)-reducing ability of strain CRB-1 and its chromate reductases enables CRB-1 a potential candidate for Cr(VI) bioremediation.


Assuntos
Bacillus/metabolismo , Cromo/metabolismo , Esgotos/microbiologia , Poluentes Químicos da Água/metabolismo , Bacillus/genética , Bacillus/isolamento & purificação , Proteínas de Bactérias/genética , Biodegradação Ambiental , Citoplasma/metabolismo , Matriz Extracelular de Substâncias Poliméricas , Proteínas de Membrana/genética , Oxirredução , Oxirredutases/genética , Oxirredutases/metabolismo
12.
Ecotoxicol Environ Saf ; 185: 109679, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31550564

RESUMO

Sodium sulfide (Na2S) was used as an inducer to regulate the components of Bacillus vallismortis sp. EPS (Extracellular Polymeric Substances). The main objective of this study was to improve the content of sulfhydryl protein and the adsorption property of EPS to Zn (Ⅱ) that as an typical heavy metal. The results showed that the maximum EPS production of 105.58 mg/g VSS coupling with doubled increase in protein in which the contant of -SH increased by 48.2% from 104.15 to 154.36 µmol/L were recorded in the presence of 20 mg/L Na2S. Under this condition, the adsorption capacity of S-EPS (EPS with added exogenous Na2S) for Zn (Ⅱ) was highest. The kinetics of the adsorption process of Zn (Ⅱ) by the S-EPS can be well fitted by the Langmuir isotherm model and the theoretical maximum adsorption amount of 979.09 mg/g EPS could be obtained. The results of 3D-EEM and FTIR analyses, illustrated that -SH, CO, and N-H/C-N played major roles in the removal of Zn (Ⅱ) by S-EPS. The results obtained in this study demonstrated that the addition of sulfur source could increase the content of sulfhydryl protein, and effectively regulate the content of chemical composition, expecially for the sulfhydryl of EPS, and thereby greatly improving the removal efficiency of heavy metals, which showed a great application prospect in the prevention and control of heavy metal pollution.


Assuntos
Bacillus/metabolismo , Poluentes Ambientais/metabolismo , Matriz Extracelular de Substâncias Poliméricas/metabolismo , Metais Pesados/metabolismo , Sulfetos/farmacologia , Adsorção , Cinética
13.
Adv Mater ; 31(43): e1903793, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31490587

RESUMO

Spores, the dormant life forms of probiotics, can germinate to metabolically active vegetative cells with the disintegration of their hydrophobic protein coat in the intestinal microenvironment, which provides the possibility for the formation of nanoparticles (NPs) in vivo. Inspired by the natural physiological process of spores, herein, an oral autonomous NPs generator is developed to overcome the spatially variable gastrointestinal tract environment and multibiological barriers. Spores modified with deoxycholic acid (DA) and loaded with chemotherapeutic drugs (doxorubicin and sorafenib, DOX/SOR) serve as an autonomous production line of NPs, which can efficaciously protect the drugs passing through the rugged environment of the stomach and furthermore can be transported to the intestinal environment and colonized rapidly. Subsequently, the DOX/SOR/Spore-DA NPs are produced by the autonomous NPs generator in the intestinal regions based on the disintegrated hydrophobic protein and the hydrophilic DA, and they can efficiently penetrate the epithelial cells via the bile acid pathway, increasing basolateral drug release. In vitro and in vivo studies confirm that this biological nanogenerator can autonomously produce substantial NPs in the intestine, providing a promising strategy for cancer therapy.


Assuntos
Neoplasias do Colo/tratamento farmacológico , Sistemas de Liberação de Medicamentos/métodos , Nanomedicina/métodos , Nanopartículas/metabolismo , Nanopartículas/uso terapêutico , Probióticos/metabolismo , Esporos/metabolismo , Administração Oral , Animais , Bacillus/metabolismo , Transporte Biológico , Células CACO-2 , Linhagem Celular Tumoral , Neoplasias do Colo/patologia , Doxorrubicina/química , Doxorrubicina/metabolismo , Doxorrubicina/farmacologia , Humanos , Absorção Intestinal , Camundongos , Sorafenibe/química , Sorafenibe/metabolismo , Sorafenibe/farmacologia
14.
Environ Sci Pollut Res Int ; 26(30): 31392-31400, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31471855

RESUMO

Tetrabromobisphenol A (TBBPA) is an emerging contaminant and exists widely in river and lake systems due to its widespread use. In natural water-sediment systems, hydrodynamic disturbances always exist. However, few studies have investigated the mechanism of TBBPA biodegradation under the influence of water disturbances. In this paper, using a specialized type of racetrack-style flumes, the TBBPA biodegradation in water-sediment systems was studied under the influence of three typical hydrodynamic disturbances. The results of 5-week experiments showed that strong hydrodynamic disturbances greatly accelerate the TBBPA biodegradation rate of the water-sediment systems. The half-lives (T1/2) under static condition (SC) were approximately 40.2 days, and the T1/2 was reduced to 16.0 days under strong hydrodynamic condition (SHC). Furthermore, the physicochemical properties and corresponding bacterial communities under these conditions were investigated to help explain the TBBPA biodegradation mechanism. The results showed that strong currents could promote dissolved oxygen (DO) levels, increase nutrient concentrations, and reduce the bacterial diversity in the sediment. Meanwhile, due to the increase in DO and nutrient concentrations, the aerobic bacterial genera conducting TBBPA biodegradation showed rapid growth with strong water disturbances, while the growth of anaerobic bacterial genera was inhibited. Citrobacter, which was the most dominant degrading bacterial genus (0.6%-14.9% in water and 3.5%-17.4% in sediment), was closely related to water disturbances and may be linked to enhanced TBBPA biodegradation. Other minor degrading bacterial genera, such as Bacillus, Sphingomonas, Anaeromyxobacter, Geobacter, Clostridium, and Flavobacterium, were also found in these water-sediment systems. The findings from this study showed the importance of considering hydrodynamic disturbance in understanding TBBPA biodegradation in aquatic environments.


Assuntos
Biodegradação Ambiental , Bifenil Polibromatos/metabolismo , Poluentes Químicos da Água/metabolismo , Bacillus/metabolismo , Bactérias Aeróbias/metabolismo , Sedimentos Geológicos/química , Hidrodinâmica , Lagos/química , Rios/química , Sphingomonas/metabolismo , Água/análise , Poluentes Químicos da Água/análise
15.
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
16.
Extremophiles ; 23(6): 759-764, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31538256

RESUMO

Two alkaliphilic strains, designated FJAT-45086T and FJAT-45122T, were isolated from alkali soli in Nima County, Tibet, China. Both strains were Gram-positive, rod-shaped and shared low 16S rRNA gene sequence similarity with the members of the genus Bacillus. They contained meso-diaminopimelic acid as the cell-wall diamino acid and MK-7 as the menaquinone. The major fatty acids (>5%) of strain FJAT-45086T were anteiso-C15:0, C16:0, iso-C15:0, C16:1ω11c and anteiso-C17:0, whereas strain FJAT-45122T consisted of iso-C15:0, anteiso-C15:0, iso-C17:1ω10c, iso-C17:0, anteiso-C17:0, C16:0 and C16:1ω11c. The genome G + C content of strains FJAT-45086T and FJAT-45122T was 37.8 and 38.2 mol%, respectively. The polar lipids of strain FJAT-45086T were diphosphatidyl glycerol (DPG), phosphatidyl glycerol (PG), phosphatidyl ethanolamine (PE), and phosphatidyl choline (PC), whereas strain FJAT-45122T consisted of DPG, PG, phosphatidyl methyl ethanolamine (PME) and an unidentified aminophospholipids (UAPL). The average nucleotide identity values of strains FJAT-45086T and FJAT-45122T were below the cut-off level (95-96%) for species delineation. Based on the results, strains FJAT-45086T and FJAT-45122T represent two novel species of the genus Bacillus, for which the names Bacillus alkalisoli sp. nov., and Bacillus solitudinis sp. nov., are proposed. The type strain, FJAT-45122T (=DSM 104631T = CCTCC AB 2016254T), FJAT-45086T (=DSM 104056T = CCTCC AB 2016232T).


Assuntos
Bacillus , Microbiologia do Solo , Álcalis , Bacillus/classificação , Bacillus/isolamento & purificação , Bacillus/metabolismo
17.
Biocontrol Sci ; 24(3): 129-136, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31527343

RESUMO

Previously, we isolated and examined a bacterial strain designated as TM-I-3, belonging to the genus Bacillus, from soil in Nagasaki, Japan. This bacterium was able to inhibit the growth of molds, without coming into direct contact with them. Non-contact antifungals are capable of providing multidirectional inhibition and may contribute to disease prevention. In this study, we revealed the bacteriological properties of TM-I-3 and evaluated the antifungal activity of the compounds emitted from this bacterium. In addition, we analyzed the antimicrobial substances released from TM-I-3 using GC/MS to elucidate the mechanism of its action. Antimicrobial compounds from strain TM-I-3 were identified as acetic acid, propanoic acid, isovaleric acid, 2-methylbutanoic acid, and benzaldehyde, which are all reported to have antimicrobial activity. TM-I-3 demonstrated possible efficacy in inhibiting the growth of Aspergillus fumigatus, Cladosporium cladosporioides and Penicillium expansum, which may lead to inhibition of common fungal contaminants of household products and prevention of some pulmonary diseases.


Assuntos
Antifúngicos/farmacologia , Aspergillus fumigatus/efeitos dos fármacos , Bacillus/metabolismo , Cladosporium/efeitos dos fármacos , Penicillium/efeitos dos fármacos , Compostos Orgânicos Voláteis/farmacologia , Antifúngicos/química , Antifúngicos/metabolismo , Aspergillus fumigatus/crescimento & desenvolvimento , Bacillus/classificação , Bacillus/genética , Cladosporium/crescimento & desenvolvimento , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Cromatografia Gasosa-Espectrometria de Massas , Japão , Penicillium/crescimento & desenvolvimento , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/metabolismo
18.
J Dairy Sci ; 102(12): 10799-10813, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31521346

RESUMO

Spore formers are common spoilage-causing microorganisms in dairy products; however, their modes of spoilage (proteolysis, lipolysis, etc.) have not been described in detail for cultured dairy products such as sour cream and yogurt. The objective of the present study was to test the ability of spore-forming strains isolated from dairy environments for their spoilage-causing activities at typical sour cream (24°C) and yogurt (42°C) fermentation temperatures. A total of 25 spore-forming strains were isolated from different sources, including raw milk, pasteurizer balance tank, biofilms formed on heat exchangers, and milk powder. These strains were tested for proteolytic and lipolytic activities and for their ability to degrade phospholipids, common stabilizers (starch, gelatin, xanthan gum, pectin), and exopolysaccharides (EPS) at sour cream and yogurt fermentation temperatures. A higher percentage of positive strains was observed for selected activities at yogurt fermentation temperature compared with sour cream fermentation temperature. Identified proteolytic spore-forming strains, based on a skim milk agar method, were subsequently quantified for their level of proteolysis using non-casein nitrogen (NCN) content and sodium dodecyl sulfate-PAGE (SDS-PAGE). The proteolytic strains that showed the highest levels of proteolysis (highest percentages of NCN content) at 24°C were Bacillus mojavensis BC, Bacillus cereus DBC, Bacillus subtilis DBC, B. mojavensis DBC1, and Paenibacillus polymyxa DBC1. At 42°C the strains with the highest levels of proteolysis (highest percentages of NCN content) were B. subtilis DBC, B. mojavensis BC, B. mojavensis DBC1, B. cereus DBC, and Bacillus licheniformis DBC6. Results of SDS-PAGE demonstrated that proteolytic strains had primarily hydrolyzed ß- and κ-CN. A viscometric method was used to evaluate the susceptibility of exopolysaccharides (EPS) to degradation by selected spore formers. This method helped to determine that EPS produced by commercial yogurt and sour cream cultures is susceptible to degradation by spore formers present in dairy environments.


Assuntos
Bacillus/metabolismo , Proteínas do Leite/metabolismo , Leite/microbiologia , Fosfolipídeos/metabolismo , Animais , Fermentação , Microbiologia de Alimentos , Leite/metabolismo , Paenibacillus/metabolismo , Pasteurização , Esporos , Temperatura , Iogurte/microbiologia
19.
J Microbiol Biotechnol ; 29(11): 1777-1789, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31546292

RESUMO

Drought is more concerned to be a huge problem for agriculture as it affects plant growth and yield. Endophytic bacteria act as plant growth promoting bacteria that have roles for improving plant growth under stress conditions. The properties of four strains of endophytic bacteria were determined under water deficit medium with 20% polyethylene glycol. Bacillus aquimaris strain 3.13 showed high 1-aminocyclopropane-1-carboxylate (ACC) deaminase production; Micrococcus luteus strain 4.43 produced indole acetic acid (IAA). Exopolysaccharide production was high in Bacillus methylotrophicus strain 5.18 while Bacillus sp. strain 5.2 did not show major properties for drought response. Inoculation of endophytic bacteria into plants, strain 3.13 and 4.43 increased height, shoot and root weight, root length, root diameter, root volume, root area and root surface of Jerusalem artichoke grown under water limitation, clearly shown in water supply at 1/3 of available water. These increases were caused by bacteria ACC deaminase and IAA production; moreover, strain 4.43 boosted leaf area and chlorophyll levels, leading to increased photosynthesis under drought at 60 days of planting. The harvest index was high in the treatment with strain 4.43 and 3.13 under 1/3 of available water, promoting tuber numbers and tuber weight. Inulin content was unchanged in the control between well-watered and drought conditions. In comparison, inulin levels were higher in the endophytic bacteria treatment under both conditions, although yields dipped under drought. Thus, the endophytic bacteria promoted in plant growth and yield under drought; they had outstanding function in the enhancement of inulin content under wellwatered condition.


Assuntos
Secas , Endófitos/fisiologia , Helianthus/crescimento & desenvolvimento , Helianthus/microbiologia , Estresse Fisiológico , Bacillus/metabolismo , Bacillus/fisiologia , Biomassa , Carbono-Carbono Liases/metabolismo , Clorofila/metabolismo , Endófitos/metabolismo , Helianthus/metabolismo , Ácidos Indolacéticos/metabolismo , Inulina/metabolismo , Micrococcus luteus/metabolismo , Micrococcus luteus/fisiologia , Fotossíntese , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Polissacarídeos Bacterianos/metabolismo
20.
J Sci Food Agric ; 99(15): 6903-6910, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31415094

RESUMO

BACKGROUND: Bacillus thuringiensis (Bt) synthesizes Cry1Ac protein, which is toxic to many lepidopteran pests, and the cry1ac gene has been expressed in several transgenic crop plants. The Cry1Ac protein has been isolated from Bt kurstaki HD73 and purified to homogeneity. Polyclonal antibodies were raised against purified Cry1Ac in rabbits and goat. Sandwich ELISA was developed for Cry1Ac using goat IgG as a coating antibody, and affinity-purified rabbit IgG as the primary antibody. RESULTS: The sensitivity of the assay was in the range of 0.47-1000 ng. It was subsequently employed in validating biological samples. Fifteen different cotton-seed samples were screened: 12 were found to be Bt positive and 3 Bt negative. The CS7 seeds showed the highest Bt content of 8.51 ± 0.45 µg g-1 , followed by CS8 (6.0 ± 0.02 µg g-1 ), CS15 (5.9 ± 0.03 µg g-1 ), CS9 (5.5 ± 0.05 µg g-1 ), and CS10 (4.83 ± 0.013 µg g-1 ). The CS5 seeds showed Bt content of 3.6 ± 0.21 µg g-1 . The F2 generation, CS6 (Kaveri seeds) showed lower Bt content (2.9 ± 0.06 µg g-1 ). The CL5 samples showed Cry1Ac content of 0.99 ± 0.009 µg g-1 . The amount of Cry1Ac protein in leaves, stem, and roots of germinated Bt cotton plants (CS10 and CS4) were 1.76 ± 0.15 µg g-1 , 1.9 ± 0.01 µg g-1 , 2.0 ± 0.1 µg g-1 , and 1.6 ± 0.15 µg g-1 , 1.9 ± 0.01 µg g-1 , and 2.0 ± 0.01 µg g-1 dry tissue, respectively. CONCLUSION: The method developed can be used for screening the expression levels of Cry1Ac in different transgenic Bt cultivars and also spurious Bt cotton seeds procured by farmers. © 2019 Society of Chemical Industry.


Assuntos
Bacillus/química , Endotoxinas/análise , Ensaio de Imunoadsorção Enzimática/métodos , Gossypium/química , Plantas Geneticamente Modificadas/química , Animais , Anticorpos/análise , Anticorpos/imunologia , Bacillus/metabolismo , Endotoxinas/imunologia , Endotoxinas/metabolismo , Gossypium/genética , Gossypium/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Coelhos , Sementes/química , Sementes/genética , Sementes/metabolismo
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