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1.
Ecotoxicol Environ Saf ; 201: 110860, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32563162

RESUMO

The biodegradation of naphthalene using low-density polyethylene (LDPE) immobilized Exiguobacterium sp. RKS3 (MG696729) in a packed bed bioreactor (PBBR) was studied. The performance of a continuous PBBR was evaluated at different inlet flow rates (IFRs) (20-100 mL/h) under 64 days of operation. The maximum naphthalene removal efficiency (RE) was found at low IFR, and it further decreased with increasing IFRs. In a continuous PBBR, the external mass transfer (EMT) aspect was analysed at various IFRs, and experimental data were interrelated between Colburn factor (JD) and Reynolds number (NRe) as [Formula: see text] . A new correlation [Formula: see text] was obtained to predict the EMT aspect of naphthalene biodegradation. Andrew-Haldane model was used to evaluate the bio-kinetic parameters of naphthalene degradation, and kinetic constant νmax, Js, and Ji were found as 0.386 per day, 13.6 mg/L, and 20.54 mg/L, respectively.


Assuntos
Reatores Biológicos/microbiologia , Naftalenos/análise , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Bacillales/crescimento & desenvolvimento , Bacillales/metabolismo , Biodegradação Ambiental , Células Imobilizadas/microbiologia , Cinética , Polietileno/química
2.
PLoS One ; 15(6): e0234958, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32574185

RESUMO

Proteases play an essential role in living organisms and represent one of the largest groups of industrial enzymes. The aim of this work was recombinant production and characterization of a newly identified thermostable protease 1147 from thermophilum indigenous Cohnella sp. A01. Phylogenetic tree analysis showed that protease 1147 is closely related to the cysteine proteases from DJ-1/ThiJ/PfpI superfamily, with the conserved catalytic tetrad. Structural prediction using MODELLER 9v7 indicated that protease 1147 has an overall α/ß sandwich tertiary structure. The gene of protease 1147 was cloned and expressed in Escherichia coli (E. coli) BL21. The recombinant protease 1147 appeared as a homogenous band of 18 kDa in SDS-PAGE, which was verified by western blot and zymography. The recombinant protein was purified with a yield of approximately 88% in a single step using Ni-NTA affinity chromatography. Furthermore, a rapid one-step thermal shock procedure was successfully implemented to purify the protein with a yield of 73%. Using casein as the substrate, Km, and kcat, kcat/Km values of 13.72 mM, 3.143 × 10-3 (s-1), and 0.381 (M-1 S-1) were obtained, respectively. The maximum protease activity was detected at pH = 7 and 60°C with the inactivation rate constant (kin) of 2.10 × 10-3 (m-1), and half-life (t1/2) of 330.07 min. Protease 1147 exhibited excellent stability to organic solvent, metal ions, and 1% SDS. The protease activity was significantly enhanced by Tween 20 and Tween 80 and suppressed by cysteine protease specific inhibitors. Docking results and molecular dynamics (MD) simulation revealed that Tween 20 interacted with protease 1147 via hydrogen bonds and made the structure more stable. CD and fluorescence spectra indicated structural changes taking place at 100°C, very basic and acidic pH, and in the presence of Tween 20. These properties make this newly characterized protease a potential candidate for various biotechnological applications.


Assuntos
Bacillales/enzimologia , Proteínas de Bactérias/química , Peptídeo Hidrolases/química , Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/ultraestrutura , Clonagem Molecular , Ensaios Enzimáticos , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Simulação de Dinâmica Molecular , Peso Molecular , Peptídeo Hidrolases/isolamento & purificação , Peptídeo Hidrolases/ultraestrutura , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/ultraestrutura , Especificidade por Substrato
3.
Arch Microbiol ; 202(7): 1831-1838, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32447434

RESUMO

A novel, Gram-stain-positive bacterium, designated KC615T, was isolated from desert soil which was collected from the Karakum Desert, Turkmenistan. Phylogenetic analysis based on an almost-complete 16S rRNA gene sequence showed that isolate KC615T formed a monophyletic clade with Shimazuella kribbensis KCTC 9933T, sharing 98.2% similarity and polyphasic taxonomic studies confirmed the affiliation of the strain to the genus Shimazuella. The cell-wall peptidoglycan contained meso-diaminopimelic acid. Whole-cell hydrolysates contained ribose and glucose. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and hydroxy-phosphatidylethanolamine. The predominant menaquinones (> 10%) were MK-9(H4) and MK-10(H4). Major fatty acids were anteiso-C15:0, C20:0 and C18:0. The genomic DNA G + C content observed for strain KC615T was 38.5 mol%. Based on 16S rRNA gene similarity, DNA-DNA hybridization value, chemotaxonomic characteristics and differential physiological properties, strain KC615T is considered to represent a novel species within the genus Shimazuella, for which the name Shimazuella alba sp. nov. is proposed. The type strain is KC615T (= JCM 33532T = CGMCC 4.7616T).


Assuntos
Bacillales/classificação , Filogenia , Microbiologia do Solo , Bacillales/genética , Bacillales/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Clima Desértico , Ácido Diaminopimélico/análise , Ácidos Graxos/análise , Peptidoglicano/genética , Fosfolipídeos/análise , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Especificidade da Espécie , Turcomenistão
4.
Lett Appl Microbiol ; 70(6): 407-412, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32133659

RESUMO

Inactivation of Bacillales and Clostridiales spores is of interest, since some cause food spoilage and human diseases. A recent publication (mSphere 3: e00597-1, 2018) reported that glycerol monolaurate (GML) in a non-aqueous gel (GMLg) effectively killed spores of Bacillus subtilis, Bacillus cereus and Clostridioides difficile, and Bacillus anthracis spores to a lesser extent. We now show that (i) the B. subtilis spores prepared as in the prior work were impure; (ii) if spore viability was measured by diluting spores 1/10 in GMLg, serially diluting incubations 10-fold and spotting aliquots on recovery plates, there was no colony formation from the 1/10 to 1/1000 dilutions due to GMLg carryover, although thorough ethanol washes of incubated spores eliminated this problem and (iii) GMLg did not kill highly purified spores of B. subtilis, B. cereus, Bacillus megaterium and C. difficile in 3-20 h in the conditions used in the recent publication. GMLg also gave no killing of crude B. subtilis spores prepared as in the recent publication in 5 h but gave ~1·5 log killing at 24 h. Thus, GMLg does not appear to be an effective sporicide, although the gel likely inhibits spore germination and could kill spores somewhat upon long incubations. SIGNIFICANCE AND IMPACT OF THE STUDY: Given potential deleterious effects of spores of Bacillales and Clostridiales, there is an ongoing interest in new ways of spore killing. A recent paper (mSphere 3: e00597-1, 2018) reported that glycerol monolaurate (GML) in a non-aqueous gel (GMLg) effectively killed spores of many species. We now find that (i) the Bacillus subtilis spores prepared as in the previous report were impure and (ii) GMLg gave no killing of purified spores of Bacillales and Clostridiales species in ≤5 h under the published conditions. Thus, GMLg is not an effective sporicide, though may prevent spore germination or kill germinated spores.


Assuntos
Antibacterianos/farmacologia , Bacillales/efeitos dos fármacos , Clostridiales/efeitos dos fármacos , Lauratos/farmacologia , Monoglicerídeos/farmacologia , Esporos Bacterianos/efeitos dos fármacos , Esporos Bacterianos/crescimento & desenvolvimento , Bacillales/crescimento & desenvolvimento , Bacillus cereus/efeitos dos fármacos , Bacillus megaterium/efeitos dos fármacos , Bacillus subtilis/efeitos dos fármacos , Clostridiales/crescimento & desenvolvimento , Clostridium difficile/efeitos dos fármacos , Microbiologia de Alimentos , Géis/farmacologia
5.
Int J Syst Evol Microbiol ; 70(4): 2602-2610, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32160142

RESUMO

A novel Gram-stain-positive, aerobic, motile with peritrichous flagella, rod-shaped bacterium, designated CC-MHH1044T, was isolated from a preserved vegetable sample. A polyphasic taxonomic approach was applied to the isolates in order to clarify its taxonomic position. Growth of the strain CC-MHH1044T occurred at 15-50 °C (optimum, 30 °C), pH 6.0-8.0 (optimum, pH 7.0) and with 0-2.0 % (w/v) NaCl (optimum, 1 %, w/v). The genome of strain CC-MHH1044T consisted of 8.5 Mb and the genomic DNA G+C content was 58.5 mol%. Comparison of the 16S rRNA gene sequences showed that CC-MHH1044T belonged to the genus Cohnella and showed a close relationship with the type strains of Cohnella damuensis (96.2 %) and Cohnella panacarvi (95.9 %), and lower sequence similarity to other species. Average nucleotide identity values calculated from whole-genome sequencing data proved that CC-MHH1044T represents a distinct Cohnella species. The dominant cellular fatty acids (>5 %) included iso-C14 : 0(7.4 %), iso-C15 : 0 (6.4 %), anteiso-C15 : 0(40.3 %), C16 : 0 (6.6 %) and iso-C16 : 0 (27.0 %). The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, four unidentified aminophospholipids, one unidentified phospholipid and glycolipid. The major polyamine was spermidine. The predominant isoprenoid quinone was menaqinone 7 (MK-7). Based on its distinct phylogenetic, phenotypic and chemotaxonomic traits, together with results of comparative 16S rRNA gene sequence, average nucleotide identity and digital DNA-DNA hybridization analyses, we conclude that strain CC-MHH1044T represents a novel member of the genus Cohnella, for which the name Cohnella fermenti sp. nov. is proposed. The type strain is CC-MHH1044T (=BCRC 81147T=JCM 32834T).


Assuntos
Bacillales/classificação , Fermentação , Alimentos e Bebidas Fermentados/microbiologia , Filogenia , Bacillales/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Microbiologia de Alimentos , Glicolipídeos/química , Naftóis/química , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Taiwan , Terpenos/química , Sequenciamento Completo do Genoma
6.
Arch Microbiol ; 202(5): 1223-1229, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32103285

RESUMO

A Gram-negative and facultative anaerobic bacterium, designated strain SN4T, was isolated from the stool sample of an obese Amazonian patient. The new isolate was characterized by the taxonogenomics approach. The strain SN4T was beige-colored, circular and not haemolytic. Cells are rod shaped and motile with several flagella. Strain SN4T grows optimally at pH 7 and can survive in the presence of a saline concentration of up to 75 g/l NaCl. The 16S ribosomal RNA gene sequence analysis of the novel strain SN4T showed 95.28% similarity in nucleotide sequence with Gorillibacterium massiliense G5T, the phylogenetically closest neighbor and the type species of this genus. Anteiso-C15:0, iso-C15:0 and C16:0 were found as the major components in the cellular fatty acid analysis of this isolate. The genomic draft of strain SN4T is 5,263,742 bp long with 53.33% of G+C content. The differences in physiological, biochemical characteristics and phylogenetic and genomic data make it possible to clearly distinguish the strain SN4T from G. massiliense G5T. Based on the taxonogenomic description and the phenotypic and biochemical characteristics of this bacterium presented in this article, we propose the SN4T strain (= CSUR P2011 = DSM 100,698) as a new species, Gorillibacterium timonense sp. nov.


Assuntos
Bacillales/classificação , Filogenia , Bacillales/genética , Bacillales/isolamento & purificação , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/análise , Fezes/microbiologia , Genômica , Humanos , Obesidade , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Especificidade da Espécie
7.
J Microbiol ; 58(1): 24-29, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31768939

RESUMO

Strain ATSA2T was isolated from surface-sterilized kimchi cabbage (Brassica rapa subsp. pekinensis) seeds and represents a novel bacterium based on the polyphasic taxonomic approach. A phylogenetic analysis based on 16S rRNA gene sequences showed that strain ATSA2T formed a lineage within genus Saccharibacillus and was most closely to Saccharibacillus deserti WLG055T (98.1%) and Saccharibacillus qing-shengii H6T (97.9%). The whole-genome of ATSA2T comprised a 5,619,468 bp of circular chromosome with 58.4% G + C content. The DNA-DNA relatedness values between strain ATSA2T and its closely related type strains S. deserti WLJ055 and S. qingshengii H6T were 26.0% and 24.0%, respectively. Multiple gene clusters associated with plant growth promotion activities (stress response, nitrogen and phosphorus metabolism, and auxin biosynthesis) were annotated in the genome. Strain ATSA2T was Gram-positive, endospore-forming, facultatively anaerobic, and rod-shaped It grew at 15-37°C (optimum 25°C), pH 6.0-10.0 (optimum pH 8.0), and in the presence of 0-5% (w/v) NaCl (optimum 1%). The major cellular fatty acids (> 10%) of strain ATSA2T were anteiso-C15:0 and C16:0. MK-7 was the major isoprenoid quinone. The major polar lipids present were diphosphatidylglycerol, phosphatidylglycerol, and three unknown glycolipids. Based on its phylogenetic, genomic, phenotypic, and chemotaxo-nomic features, strain ATSA2T is proposed to represent a novel species of genus Saccharibacillus, for which the name is Saccharibacillus brassicae sp. nov. The type strain is ATSA2T (KCTC 43072T = CCTCC AB 2019223T).


Assuntos
Bacillales/classificação , Bacillales/isolamento & purificação , Brassica rapa/microbiologia , Sementes/microbiologia , Técnicas de Tipagem Bacteriana/métodos , Filogenia , RNA Ribossômico 16S/genética
8.
Enzyme Microb Technol ; 132: 109443, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31731969

RESUMO

l-Ribose is an important pharmaceutical intermediate that is used in the synthesis of numerous antiviral and anticancer drugs. However, it is a non-natural and expensive rare sugar. Recently, the enzymatic synthesis of l-ribose has attracted considerable attention owing to its considerable advantages over chemical approaches. In this work, a new strategy was developed for the production of l-ribose from the inexpensive starting material l-arabinose. The l-arabinose isomerase (l-AIase) gene from Alicyclobacillus hesperidum and the d-lyxose isomerase (d-LIase) gene from Thermoflavimicrobium dichotomicum were cloned and co-expressed in Escherichia coli, resulting in recombinant cells harboring the vector pCDFDuet-Alhe-LAI/Thdi-DLI. The co-expression system exhibited optimal activity at a temperature of 70 °C and pH 6.0, and the addition of Co2+ enhanced the catalytic activity by 27.8-fold. The system containing 50 g L-1 of recombinant cells were relatively stable up to 55 °C. The co-expression system (50 g L-1 of recombinant cells) afforded 20.9, 39.7, and 50.3 g L-1 of l-ribose from initial l-arabinose concentrations of 100, 300, and 500 g L-1, corresponding to conversion rate of 20.9%, 13.2%, and 10.0%, respectively. Overall, this study provides a viable approach for producing l-ribose from l-arabinose under slightly acidic conditions using a co-expression system harboring l-AIase and d-LIase genes.


Assuntos
Aldose-Cetose Isomerases/metabolismo , Arabinose/metabolismo , Pentoses/metabolismo , Ribose/biossíntese , Aldose-Cetose Isomerases/genética , Alicyclobacillus/enzimologia , Alicyclobacillus/genética , Bacillales/enzimologia , Bacillales/genética , Clonagem Molecular , Escherichia coli/genética , Concentração de Íons de Hidrogênio , Pentoses/genética , Temperatura
9.
Int J Syst Evol Microbiol ; 69(11): 3362-3367, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31622228

RESUMO

A novel Gram-stain-negative bacterium, designated as SCSIO 06110T, was isolated from a deep-sea sediment of the West Pacific Ocean. Cells were 0.5-0.8 µm in width and 3.0-4.0 µm in length, spore-forming, rod-shaped with peritrichous flagella. Positive for catalase and urease, negative for oxidase and nitrate reduction. Growth occurred at 15-37 °C, pH 6-9 and 1-5 % (w/v) NaCl, with optimum growth at 28 °C, pH 7 and 3 % (w/v) NaCl. MK-7 was the only menaquinone. The strain possessed diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and two unidentified phospholipids. Iso-C16 : 0, iso-C15 : 0 and iso-C14 : 0 were the major fatty acids. The novel isolate clustered with genera in the family Paenibacillaceae, but formed a separated branch with the closest relative Chengkuizengella sediminis J15A17T (91.1 % sequence similarity) when compared in a phylogenetic analysis of 16S rRNA gene sequences. The DNA G+C content of strain SCSIO 06110T was 38.5 mol%. Based on the polyphasic data presented, a new genus, Longirhabdus gen. nov., is proposed in the family Paenibacillaceae with the type species Longirhabdus pacifica sp. nov. and the type strain SCSIO 06110T (=DSM 105158T=CGMCC 1.16550T).


Assuntos
Bacillales/classificação , Sedimentos Geológicos/microbiologia , Fontes Hidrotermais/microbiologia , Filogenia , Bacillales/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Oceano Pacífico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Água do Mar/microbiologia , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
10.
J Microbiol ; 57(11): 953-958, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31463785

RESUMO

A strictly aerobic, motile, endospore-forming, rod-shaped bacterium, designated HS21T, was isolated from rhizospheric soil of the Korean fir tree (Abies koreana) from Halla mountain on Jeju island, Korea. Growth of strain HS21T was observed at pH 6.0-8.0 (optimum: pH 7.0), 0-2% (w/v) NaCl and 4-30°C (optimum: 25°C). A comparative analysis of 16S rRNA gene sequences showed that strain HS21T was most closely related to Cohnella luojiensis HY-22RT (97.6%), followed by C. lupini RLAHU4BT (97.4%) and C. collisoli NKM-5T (97.2%). The genome of strain HS21T comprised a circular chromosome of 7,059,027 bp with 44.8% G + C content. The DNA-DNA relatedness values between strain HS21T and C. luojiensis HY-22RT and C. lupini RLAHU4BT were 18.1% and 13.8%, respectively. The major cellular fatty acids (> 5%) of the isolate were anteiso-C15:0, iso-C16:0, C16:0, and iso-C15:0. The polar lipids present were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, lysylphosphatidylglycerol, and three unidentified aminophospholipids. Based on its phenotypic, phylogenetic, genomic, and chemotaxonomic properties, strain HS21T represents a novel species of the genus Cohnella, for which the name Cohnella abietis sp. nov. is proposed. The type strain is HS21T (= KCTC 43028T = CCTCC AB 2019010T).


Assuntos
Abies/microbiologia , Bacillales/classificação , Bacillales/isolamento & purificação , Filogenia , Rizosfera , Microbiologia do Solo , Bacillales/genética , Bacillales/fisiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Lipídeos/química , Lisina/química , Fosfatidilgliceróis/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , República da Coreia , Nódulos Radiculares de Plantas/microbiologia , Análise de Sequência de DNA , Solo , Sequenciamento Completo do Genoma
11.
Int J Syst Evol Microbiol ; 69(9): 2709-2716, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31310191

RESUMO

Moutai-flavour Daqu is an important starter to support growth of microorganisms in the fermented process of Moutai-flavour liquor. A novel thermophilic microorganism, designated strain FBKL4.011T, was isolated from Moutai-flavour Daqu samples collected from Guotai distillery in Renhuai, Guizhou province, south-west China. The strain could grow at 45-65 °C (optimum 45 °C). Based on polyphasic analysis, strain FBKL4.011T was affiliated to the genus Thermoflavimicrobium. It formed abundant pale-yellow aerial and substrate mycelium, bearing single endospores (7.0-10.0 µm diameter) on branched long sporophores (5.0 µm diameter). The cell-wall peptidoglycan contained meso-diaminopimelic acid; ribose, glucose and mannose were the primary whole-cell sugars. The major fatty acids were iso-C14 : 0, iso-C15 : 0, anteiso-C15 : 0 and iso-C16 : 0. The predominant menaquinone were MK-8 and MK-9. The polar phospholipids contained diphosphatidyl glycerol, phosphatidyl ethanolamine, one unidentified phospholipid and one unidentified lipid. The G+C content of the genome was 43.1 mol%. According to the 16S rRNA gene sequence analysis, strain FBKL4.011T was closely related to Thermoflavimicrobium dichotomicum JCM 9688T (95.3 % sequence similarity), and other members within the family Thermoactinomycetaceae (less than 93.0 % sequence similarity). The DNA-DNA hybridisation data showed low relatedness between strain FBKL4.011T and T. dichotomicum JCM 9688T, Laceyella sacchari KCTC 9790T, Laceyella tengchongensis YIM 10002T, Laceyella sediminis RHA1T(36.7±1.1 %, 30.0±1.2 %, 21.3±2.1 % % and 37.6±0.9 %, respectively). Based on data from the polyphasic analysis, strain FBKL4.011T is considered to represent a novel species of the genus Thermoflavimicrobium, for which the name Thermoflavimicrobium daqui sp. nov. is proposed. The type strain is FBKL4.011T(=KCTC 43036T=CICC 24504T).


Assuntos
Bebidas Alcoólicas/microbiologia , Bacillales/classificação , Filogenia , Bacillales/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Peptidoglicano/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Esporos Bacterianos , Vitamina K 2/química
12.
ACS Chem Biol ; 14(8): 1727-1736, 2019 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-31310497

RESUMO

Bacterial resistance represents a major health threat worldwide, and the development of new therapeutics, including innovative antibiotics, is urgently needed. We describe a discovery platform, centered on in silico screening and in vivo bioluminescence resonance energy transfer in yeast cells, for the identification of new antimicrobials that, by targeting the protein-protein interaction between the ß'-subunit and the initiation factor σ70 of bacterial RNA polymerase, inhibit holoenzyme assembly and promoter-specific transcription. Out of 34 000 candidate compounds, we identified seven hits capable of interfering with this interaction. Two derivatives of one of these hits proved to be effective in inhibiting transcription in vitro and growth of the Gram-positive pathogens Staphylococcus aureus and Listeria monocytogenes. Upon supplementation of a permeability adjuvant, one derivative also effectively inhibited Escherichia coli growth. On the basis of the chemical structures of these inhibitors, we generated a ligand-based pharmacophore model that will guide the rational discovery of increasingly effective antibacterial agents.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , RNA Polimerases Dirigidas por DNA/antagonistas & inibidores , Indóis/farmacologia , Fator sigma/antagonistas & inibidores , Antibacterianos/toxicidade , Bacillales/efeitos dos fármacos , Proteínas de Bactérias/metabolismo , RNA Polimerases Dirigidas por DNA/metabolismo , Descoberta de Drogas , Eritrócitos/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Holoenzimas/metabolismo , Humanos , Indóis/toxicidade , Ligantes , Testes de Sensibilidade Microbiana , Estudo de Prova de Conceito , Ligação Proteica/efeitos dos fármacos , Saccharomyces cerevisiae/efeitos dos fármacos , Fator sigma/metabolismo
13.
Int J Biol Macromol ; 136: 1228-1236, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31228499

RESUMO

It is highly desirable to lower the glycemic index of rice starch-based foods. Herein, rice starch granules were treated sequentially with ß-amylase (BA), transglucosidase (TG) and pullulanase (PUL). The results indicated that compared with native rice starch and PUL-modified starch, degree of crystallinity, gelatinization temperature and enthalpy of BA/TG/PUL-modified starches increased remarkably. Moreover, the functionality of BA/TG/PUL-treated starch depended enormously on TG treatment time. BA/TG/PUL-modified starch possessed the highest relative crystallinity, gelatinization temperatures and gelatinization enthalpy and the content of resistant starch at TG treatment time of 20 h and the resistant crystals were formed largely from linear chains with DP 9-11. Whether before cooking or after cooking, BA/TG/PUL-modified starches had strong resistance to enzyme hydrolysis and had lower glycemic index. This outcome may offer a novel sight for the exploitation of starch-based functional foods with low glycemic index.


Assuntos
Digestão , Glucosiltransferases/metabolismo , Glicosídeo Hidrolases/metabolismo , Oryza/química , Amido/química , Amido/metabolismo , beta-Amilase/metabolismo , Amilose/análise , Aspergillus niger/enzimologia , Bacillales/enzimologia , Culinária , Índice Glicêmico , Hidrólise , Pseudomonas/enzimologia
14.
Int J Syst Evol Microbiol ; 69(8): 2522-2526, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31210625

RESUMO

A taxonomic study was carried out on strain YPA3-1-1T, which was isolated from deep-sea sediment of the Pacific Ocean. The bacterium was Gram-stain-positive, oxidase-positive, catalase-negative, rod-shaped and spore-forming. Growth was observed at salinities of 1.0-6.0 % and at temperatures of 10-40 °C. The isolate could degrade gelatin and aesculin. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain YPA3-1-1T belonged to the genus Chengkuizengella, with the highest sequence similarity to the only typespecies, Chengkuizengella sediminis J15A17T (98.5 %). The estimated average nucleotide identity and DNA-DNA hybridization values between strain YPA3-1-1T and C. sediminis J15A17T were 88.1 and 35.0 %, respectively. The cell wall of strain YPA3-1-1T contained meso-diaminopimelic acid. The principal fatty acids (>10 %) were iso-C16 : 0 (35.5 %) and anteiso-C15 : 0 (17.5 %). The G+C content of the chromosomal DNA was 33.1 mol%. The respiratory quinone was determined to be MK-7 (100 %). The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, glycolipid and three unidentified phospholipids. The combined genotypic and phenotypic data show that strain YPA3-1-1T represents a novel species within the genus Chengkuizengella, for which the name Chengkuizengella marina sp. nov. is proposed, with the type strain YPA3-1-1T (=MCCC 1A14042T=KCTC 43019T).


Assuntos
Bacillales/classificação , Sedimentos Geológicos/microbiologia , Filogenia , Água do Mar/microbiologia , Bacillales/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Glicolipídeos/química , Hibridização de Ácido Nucleico , Oceano Pacífico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Salinidade , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
15.
Int J Syst Evol Microbiol ; 69(7): 2004-2009, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31063121

RESUMO

A Gram-stain-positive, aerobic, rod-shaped, endospore-forming bacterium, designated strain M2MS4P-1T, was isolated from surface-sterilized bark of Sonneratiaapetala sampled in Guangxi, China. The bacterium was characterized by a polyphasic approach to determine its taxonomic position. 16S rRNA gene sequence comparisons revealed that strain M2MS4P-1T belonged to the genus Cohnella and was most closely to Cohnella luojiensis HY-22RT (98.4 % similarity). The average nucleotide identity value and estimated DDH value between strain M2MS4P-1T and the type strain of C. luojiensis HY-22RT were 79.2 and 20.1 %, respectively. Neither substrate nor aerial mycelia were formed, and no diffusible pigments were observed on the media tested. Strain M2MS4P-1T grew in the pH range 6.0-9.0 (optimum, pH 7.0-8.0), at temperatures between 10-37 °C (30 °C) and in 0-1 % (w/v) NaCl (0 %). The predominant isoprenoid quinone in strain M2MS4P-1T was menaquinone-7. The major fatty acids were anteiso-C15 : 0 and iso-C16 : 0. The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, lysyl-phosphatidylglycerol, four unidentified aminophospholipids and two unidentified phospholipids. The DNA G+C content was 51.5 mol%. According to the phylogenetic, phenotypic and chemotaxonomic evidence, strain M2MS4P-1T was clearly distinguishable from other species with validly published names in the genus Cohnella and should therefore be classified as a novel species, for which we suggest the name Cohnellaendophytica sp. nov. The type strain is M2MS4P-1T (=KCTC 43011T=CGMCC 1.13745T).


Assuntos
Bacillales/classificação , Lythraceae/microbiologia , Filogenia , Casca de Planta/microbiologia , Bacillales/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Peptidoglicano/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
16.
Int J Syst Evol Microbiol ; 69(7): 2028-2036, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31066660

RESUMO

The family Thermoactinomycetaceaecomprises 43 validly published species, which were identified by a polyphasic taxonomic study based on molecular phylogenetics, physiological and biochemical characteristics. However, phylogenetic analysis merely based on 16S rRNA gene sequences cannot infer a robust and reliable phylogeny. For disentangling the phylogenetic relationships among members of this family, we used a large collection of genome data and the approach of phylogenomics, to re-examine their taxonomy. The topologies of phylogenomic trees are different from those of the 16S rRNA gene sequences. In addition, based on the average nucleotide identity, digital DNA-DNA hybridization, phenotypic and biochemical characteristics, we found that Laceyella sediminis should be reclassified as a later heterotypic synonym of Laceyella tengchongensis; and reclassified Thermoactinomyces guangxiensis as Paenactinomyces guangxiensis gen. nov., comb. nov.; and establish Novibacillaceae fam. nov. to accommodate the genus Novibacillus as the type genus. In addition, compared to values calculated directly from genome sequences, the genomic DNA G+C contents mentioned in some species descriptions are too imprecise; and the corrected G+C content values have a significantly better fit to the phylogeny. Thus, the corresponding emendations of species descriptions are also proposed. In this paper, phylogenomics has been used to resolve the classification of the family Thermoactinomycetaceae.


Assuntos
Bacillales/classificação , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Hibridização de Ácido Nucleico , Peptidoglicano/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
17.
J Econ Entomol ; 112(5): 2335-2344, 2019 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-31114867

RESUMO

Striacosta albicosta (Smith) (Lepidoptera: Noctuidae) is an important pest of corn, Zea mays L. in the Great Lakes region, which can be controlled by transgenic corn expressing Vip3A protein from Bacillus thuringiensis. To inform insect resistance management, the susceptibility, survival, and development of first, third, and fifth instar S. albicosta to Vip3A was determined using protein-overlay and corn tissue bioassays. Tissue bioassays were also used to determine the quantity of corn tissues with and without Vip3A-expression consumed by various instars. In diet bioassays, third and fifth instars were significantly less susceptible to Vip3A compared with first instars; however, no significant difference was observed in susceptibility of older instars. In tissue bioassays, survival was lowest for larvae fed Vip3A-expressing tissues, ranging from 0 to 21%, however, developmental measures of larvae fed Vip3A-expressing tissues did not differ from those fed artificial diet or tissues of other Bt events. Consumption of Vip3A × Cry1Ab tissues did not differ from that of Cry1Ab for each instar. Estimated Vip3A exposure of first instars ranged from 3 to 57 times higher than the concentration required for 99% mortality (LC99) based on the product of the reported Vip3A expression in transgenic corn tissues and the consumption observed in tissue bioassays; however, the estimated exposure of third and fifth instars to Vip3A was lower than their respective LC99. These findings suggest that first instar S. albicosta maybe exposed to a high dose of Vip3A under field conditions; however, Vip3A-expression in corn may not be high dose against older instars, increasing the risk of resistance development.


Assuntos
Bacillaceae , Bacillales , Bacillus thuringiensis , Lepidópteros , Mariposas , Animais , Proteínas de Bactérias , Endotoxinas , Great Lakes Region , Proteínas Hemolisinas , Larva , Plantas Geneticamente Modificadas , Zea mays
18.
Int Microbiol ; 22(4): 511-520, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31049768

RESUMO

The phylum Firmicutes comprises seven classes where most species are either aerobic or anaerobic endospore former. Inside Firmicutes, species allocated in the genus Bacillus and related genera are collectively named aerobic endospore-forming bacteria (AEFB), and the soil is their major reservoir. AEFB have great importance in health, agriculture, and biotechnology although the more studied species are Bacillus subtilis and the human pathogens Bacillus cereus and Bacillus anthracis. AEFB have great importance in health, agriculture, and biotechnology; although the knowledge about these organisms is based on few species, notably, Bacillus subtilis, Bacillus cereus, and Bacillus anthracis. In this work, we generated partial 16S rRNA gene sequences of both strands of 192 AEFB strains isolated from soils of Distrito Federal, Brazil (SDF strains). The resulting consensus sequences were used to obtain taxonomic assignment and establish the phylogenetic relationships among these strains. Through this approach, we could observe that classified SDF strains were distributed among genera Bacillus (169 strains; 88.02%), Paenibacillus (11; 5.73%), Lysinibacillus (6; 3.13%), Brevibacillus (4; 2.08%), Terribacillus (1; 0.52%), and Rummeliibacillus (1; 0.52%). Phylogenetic trees revealed these 192 SDF strains can be segregated into eight groups spanning families Bacillaceae and Paenibacillaceae belonging to the order Bacillales. To expand the knowledge about the diversity of these SDF strains, further studies regarding characterization with different methodologies are underway.


Assuntos
Bacillales/classificação , Bacillales/isolamento & purificação , Filogenia , Microbiologia do Solo , Bacillales/genética , Brasil , DNA Bacteriano/genética , Variação Genética , RNA Ribossômico 16S/genética , Esporos Bacterianos/classificação , Esporos Bacterianos/genética , Esporos Bacterianos/isolamento & purificação
19.
Int J Biol Macromol ; 132: 1274-1281, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30953727

RESUMO

AmyLa α-amylase gene from Laceyella sp. DS3 was heterologously expressed in E. coli BL21. E. coli BL21 maximally expressed AmyLa after 4 h of adding 0.02 mM IPTG at 37 °C. The recombinant AmyLa α-amylase was purified 2.19-fold through gel filtration and ion exchange chromatography. We immobilized the purified recombinant AmyLa α-amylase on four carriers; chitosan had the best efficiency. The recombinant free and the immobilized AmyLa α-amylase showed optimum activity in the pH ranges of 6.0-7.0 and 4.0-7.0, respectively and possessed an optimum temperature of 55 °C. The free enzyme had activation energy, Km, and Vmax of 291.5 kJ, 1.5 mg/ml, and 6.06 mg/min, respectively. The immobilized enzyme had activation energy, Km, and Vmax of 309.74 kJ, 6.67 mg/ml, and 50 mg/min, respectively. The immobilized enzyme was calcium-independent and insensitive (relative to the free enzyme) to metals. It could also be reused for seven cycles.


Assuntos
Bacillales/enzimologia , Enzimas Imobilizadas/genética , Enzimas Imobilizadas/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , alfa-Amilases/genética , alfa-Amilases/metabolismo , Enzimas Imobilizadas/química , Enzimas Imobilizadas/isolamento & purificação , Escherichia coli/genética , Expressão Gênica , Cinética , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , alfa-Amilases/química , alfa-Amilases/isolamento & purificação
20.
Food Microbiol ; 81: 40-50, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30910087

RESUMO

The major aim of the study was to establish the routes via which spoilage associated psychrotrophic bacteria contaminate poultry products at a large processing plant located in Belgium. Environmental samples were collected consisting of samples of air and swabs of food contact surfaces. Product samples were also collected consisting of modified atmosphere packaged (MAP) chicken wings and legs, which were analyzed microbiologically on the same day they were produced as well as after their sell-by date. Psychrotrophic bacteria from these samples were subsequently clustered and identified by means of MALDI-TOF MS and 16S rRNA gene sequencing. Carnobacterium maltaromaticum was determined to dominate the spoilage flora of both wings and legs. Other psychrotrophic bacteria able to grow on MRS which were identified on expired wings and legs included Carnobacterium divergens, Brocothrix thermosphacta, Lactobacillus curvatus, and Lactobacillus brevis. These were determined to arise from food contact surfaces such as cutting blades, leg hooks, Ertalon and polyurethane conveyor belts, working tables, and the hands of the operators. Importantly, it was determined that cleaning and disinfection was largely inadequate. Air was also determined to be an important vector of psychrotrophic bacteria in the processing environment, potentially contaminating the products directly or indirectly.


Assuntos
Bactérias/metabolismo , Contaminação de Alimentos , Manipulação de Alimentos , Microbiologia de Alimentos , Carne/microbiologia , Microbiologia do Ar , Animais , Bacillales/isolamento & purificação , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Sequência de Bases , Bélgica , Carnobacterium/isolamento & purificação , Galinhas , Lactobacillus/isolamento & purificação , RNA Ribossômico 16S/genética , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
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