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1.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi ; 31(3): 294-298, 2019 Jun 12.
Artigo em Chinês | MEDLINE | ID: mdl-31544410

RESUMO

OBJECTIVE: To compare the growth and reproduction of the promastigotes of Leishmania isolates from various endemic areas of visceral leishmaniasis in China in various culture media, so as to provide experimental evidence for selecting an appropriate medium for the culture of Leishmania. METHODS: A total of 3 × 105 promastigotes of KS-2, Cy and JIASHI-5 Leishmania isolates were inoculated into 1 mL NNN medium, 1 mL M199 medium supplemented with 20% fetal bovine serum medium, 1 mL M199 medium supplemented with 20% horse serum medium, and 1 mL brain heart infusion medium containing heme, respectively. All media were placed at 22 ℃ under a sterile condition, and the number of promastigotes was counted continuously for 8 days under a microscope. The growth curve was plotted for the three Leishmania isolates. RESULTS: The promastigotes of KS-2, Cy and JIASHI-5 Leishmania isolates all grew and reproduced in the NNN medium, the M199 medium supplemented with 20% fetal bovine serum medium, and the M199 medium supplemented with 20% horse serum medium. The number of promastigotes of KS-2, Cy and JIASHI-5 Leishmania isolates was all significantly higher in the NNN medium than in the M199 medium supplemented with 20% fetal bovine serum medium, and the M199 medium supplemented with 20% horse serum medium at various time points of culture (all P values < 0.05), and the number of promastigotes of the KS-2 isolate was all significantly greater than that of the Cy and JIASHI-5 isolates in the NNN medium, the M199 medium supplemented with 20% fetal bovine serum medium, and the M199 medium supplemented with 20% horse serum medium at various time points of culture (all P values < 0.05). In ad dition, the promastigotes of KS-2, Cy and JIASHI-5 Leishmania isolates failed to grow and reproduce in the brain heart infusion medium. CONCLUSIONS: The growth and reproduction of the promastigotes of various Leishmania isolates from various endemic areas of visceral leishmaniasis in China vary in the same culture medium, and the growth and reproduction of a Leishmania isolate vary in different culture media. The NNN medium best fits for the culture of Leishmania isolates in the endemic areas of visceral leishmaniasis in China.


Assuntos
Meios de Cultura , Leishmania , China , Meios de Cultura/química , Humanos , Leishmania/crescimento & desenvolvimento , Leishmaniose Visceral/parasitologia , Reprodução
2.
World J Microbiol Biotechnol ; 35(8): 126, 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-31363938

RESUMO

Isolation and identification of temperature tolerant phosphate solubilizing bacteria (TTPSB) and their use as microbial fertilizers was the main goal of the study. In this study, TTPSB were isolated from soil samples treated for 16 h at 55 °C. Their phosphate solubilizing activity was either evaluated in solid media by forming a clear zone (halo) or in liquid media by quantification of the soluble phosphate in the growth medium. Five colonies (RPS4, RPS6, RPS7, RPS8 and RPS9) were identified to be able to form a halo and two of the isolates (RPS9 and RPS7) tolerated a temperature of 55 °C. With tricalcium phosphate (TCP) as the sole P-source, the phosphate solubilizing capacity of RPS9 and RPS7 was determined to be 563.8 and 324.1 mg P L-1 in liquid Sperber medium, respectively. Both bacterial isolates were identified as Pantoea agglomerans by molecular and biochemical characterization. To be used as a microbial fertilizer a carrier system for the temperature tolerant bacteria consisting of rock phosphate, sulfur and bagasse was used. It could be established that the bacterial cell counts of the microbial fertilizers were acceptable for application after storage for 4 months at 28 °C. In a greenhouse experiment using pot cultures, inoculation of maize (S.C.704) with the microbial fertilizers in an autoclaved soil resulted in a significant effect on total fresh and dry weight of the plant root and shoot as well as on the P content of the root and shoot. The effects observed with RPS9 as a component of the microbial fertilizer on plant growth and P nutrition was comparable with the addition of 50% of recommended triple superphosphate (TSP) dose. Using temperature tolerant bacteria in microbial fertilizers will overcome limitations in production and storage of the microbial fertilizers and contribute to a environmentally-friendly agriculture. The temperature tolerant P. agglomerans strain RPS9 was shown to be effective as part of a microbial fertilizer in supporting the growth and P uptake in maize.


Assuntos
Agricultura/métodos , Fosfatos de Cálcio/metabolismo , Pantoea/isolamento & purificação , Pantoea/metabolismo , Microbiologia do Solo , Zea mays/crescimento & desenvolvimento , Técnicas Bacteriológicas , Biotransformação , Fosfatos de Cálcio/química , Meios de Cultura/química , Temperatura Alta , Pantoea/classificação , Pantoea/efeitos da radiação , Solubilidade , Zea mays/microbiologia
3.
J Microbiol ; 57(9): 759-768, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31376108

RESUMO

The cultivation of microbial species remains a primary challenge in microbiology and obtaining pure cultures is essential for the study of microbial physiology and function. When isolating microorganisms from aquaculture environments, Vibrio are the most dominate isolates on the media that are commonly used. In order to expand our ability to study microbial species, an easy-operation and low-cost medium that can reduce the interference of Vibrio strains and increase the cultivability of other bacteria is urgently needed. We compared viable cell counts on conventional media (CM; including Marine Agar 2216 and LB media) and diluted media (DM; including 1/10-Marine Agar 2216, 1/10-LB). We also assessed the diversity of cultivable microorganisms under high and low nutrient conditions by a plate-wash strategy coupled with high-throughput sequencing of the V4 hypervariable region of the 16S rRNA gene. The results show that microbial communities from DM, especially 1/10-Marine Agar 2216, are more diverse than those obtained from CM. Vibrio isolates were reduced on DM. PICRUSt analysis revealed that nutrient composition is a significant contributor to the diversity and function of the cultivable microbial communities. Bacteria grown on CM possess more pathogenic characteristics, whereas DM favors the growth of bacteria that have multiple metabolic functions. Collectively, our data provide strong evidence that dilution of CM influences the cultivability of bacteria from aquaculture seawater. It also supports that DM can expand the range of microbial species that can be cultivated. This study also provides insights for media design in microbial cultivation from aquaculture systems.


Assuntos
Meios de Cultura/metabolismo , Água do Mar/microbiologia , Vibrio/crescimento & desenvolvimento , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Meios de Cultura/química , DNA Bacteriano/genética , Filogenia , RNA Ribossômico 16S/genética , Vibrio/genética , Vibrio/isolamento & purificação , Vibrio/metabolismo
4.
World J Microbiol Biotechnol ; 35(9): 136, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31432249

RESUMO

Volatile phenols such as 4-ethylphenol are produced from hydroxycinnamic acids by Dekkera bruxellensis, an important yeast contaminating alcoholic fermentations. 4-ethylphenol results from the decarboxylation and reduction of p-coumaric acid, a compound found in sugarcane musts. In wine, volatile phenols are responsible by sensorial alterations whereas in the context of bioethanol fermentation, little is known about their effects on the main yeast, Saccharomyces cerevisiae. Here we evaluated the interaction of 4-ethylphenol and pH, sucrose and ethanol on the growth and fermentation capacity of the industrial strain of S. cerevisiae PE-2. A central compound rotational design was utilized to evaluate the effect of 4-ethylphenol, pH, ethanol and sucrose concentration on the yeast maximum specific growth rate (µmax) in microplate experiments in YPS medium (Yeast extract-Peptone-Sucrose), at 30 °C. Following, single-cycle fermentations in YPS medium, pH 4.5, 17% sucrose, at 30 °C, with 4-ethylphenol in concentrations of 10 and 20 mg L-1 being added at the start or after 4 h of fermentation, were carried out. 4-ethylphenol affected µmax of S. cerevisiae in situations that resemble the conditions of industrial bioethanol production, especially the low pH of the fermentation medium and the high ethanol concentration because of the anaerobic sucrose uptake. The addition of 4-ethylphenol on fermentation resulted in significant effect on the cell yeast concentration, pH and alcohol production, with significant decrease from 86% to the range of 65-74% in the fermentative efficiency. The industrial yeast S. cerevisiae PE-2 growth and fermentative capacity were affected by the presence of 4-ethylphenol, a metabolite produced by D. bruxellensis, which may contribute to explain the impact of this yeast on bioethanol industrial production.


Assuntos
Etanol/metabolismo , Fermentação , Microbiologia Industrial , Fenóis/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Sacarose/metabolismo , Meios de Cultura/química , Inibidores do Crescimento/metabolismo , Concentração de Íons de Hidrogênio , Saccharomyces cerevisiae/efeitos dos fármacos , Temperatura Ambiente
5.
Tumour Biol ; 41(8): 1010428319866369, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31402761

RESUMO

Gaining a better understanding of the biological properties of cell-free DNA constitutes an important step in the development of clinically meaningful cell-free DNA-based tests. Since the in vivo characterization of cell-free DNA is complicated by the immense heterogeneity of blood samples, an increasing number of in vitro cell culture experiments, which offer a greater level of control, are being conducted. However, cell culture studies are currently faced with three notable caveats. First, the concentration of cell-free DNA in vitro is relatively low. Second, the median amount and size of cell-free DNA in culture medium varies greatly between cell types. Third, the amount and size of cell-free DNA in the culture medium of a single cell line fluctuates over time. Although these are interesting findings, it can also be a great source of experimental confusion and emphasizes the importance of method optimization and standardization. Therefore, in this study, we compared five commonly used cell-free DNA quantification methods, including quantitative polymerase chain reaction, Qubit Double-Stranded DNA High Sensitivity assay, Quant-iT PicoGreen Assay, Bioanalyzer High Sensitivity DNA assay, and NanoDrop Onec. Analysis of the resulting data, along with an interpretation of theoretical values (i.e. the theoretical detection and quantification limits of the respective methods), enables the calculation of optimal conditions for several important preanalytical steps pertaining to each quantification method and different cell types, including the (1) time-point at which culture medium should be collected for cell-free DNA extraction, (2) amount of cell culture supernatant from which to isolate cell-free DNA, (3) volume of elution buffer, and (4) volume of cell-free DNA sample to use for quantification.


Assuntos
Ácidos Nucleicos Livres/química , Meios de Cultura/química , Técnicas de Cultura de Células , Corantes Fluorescentes/química , Humanos , Compostos Orgânicos/química
6.
Bioengineered ; 10(1): 335-344, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31322471

RESUMO

Selenium-enriched yeast can transform toxic inorganic selenium into absorbable organic selenium, which is of great significance for human health and pharmaceutical industry. A yeast Rhodotorula glutinis X-20 we obtained before has good selenium-enriched ability, but its selenium content is still low for industrial application. In this study, strategies of process optimization and transport regulation of selenium were thus employed to further improve the cell growth and selenium enrichment. Through engineering phosphate transporters from Saccharomyces cerevisiae into R. glutinis X-20, the selenium content was increased by 21.1%. Through using mixed carbon culture (20 g L-1, glycerol: glucose 3:7), both biomass and selenium content were finally increased to 5.3 g L-1 and 5349.6 µg g-1 (cell dry weight, DWC), which were 1.14 folds and 6.77 folds compared to their original values, respectively. Our results indicate that high selenium-enrichment ability and biomass production can be achieved through combining process optimization and regulation of selenium transport.


Assuntos
Engenharia Metabólica/métodos , Fosfatos/metabolismo , Rhodotorula/genética , Saccharomyces cerevisiae/genética , Selênio/metabolismo , Transgenes , Transporte Biológico , Biomassa , Meios de Cultura/química , Meios de Cultura/farmacologia , Fermentação , Expressão Gênica , Glucose/química , Glucose/metabolismo , Glicerol/química , Glicerol/metabolismo , Proteínas de Transporte de Fosfato/genética , Proteínas de Transporte de Fosfato/metabolismo , Plasmídeos/química , Plasmídeos/metabolismo , Simportadores de Próton-Fosfato/genética , Simportadores de Próton-Fosfato/metabolismo , Rhodotorula/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas Cotransportadoras de Sódio-Fosfato Tipo III/genética , Proteínas Cotransportadoras de Sódio-Fosfato Tipo III/metabolismo
7.
World J Microbiol Biotechnol ; 35(8): 114, 2019 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-31332537

RESUMO

N-acetyl-D-glucosamine (GlcNAc) is an important amino-monosaccharide with great potential for biotechnological applications. It has traditionally been produced by the chemical hydrolysis of chitin, despite certain industrial and environmental drawbacks, including acidic wastes, low yields and high costs. Therefore, enzymatic production has gained attention as a promising environmentally-friendly alternative to the chemical processes. In this study we demonstrate the GlcNAc bioproduction from colloidal α-chitin using an enzyme cocktail containing endochitinases and exochitinases (chitobiosidases and N-acetyl-glucosaminidases). The enzyme cocktail was extracted after fermentation in a bioreactor by Aeromonas caviae CHZ306, a chitinolytic marine bacterium with great potential for chitinase production. Hydrolysis parameters were studied in terms of temperature, pH, enzyme and substrate concentration, and reaction time, achieving over 90% GlcNAc yield within 6 h. The use of colloidal α-chitin as substrate showed a substantial improvement of GlcNAc yields, when compared with ß-chitin and α-chitin polymorphs. Such result is directly related to a significant decrease in crystallinity and viscosity from natural α-chitin, providing the chitinase with greater accessibility to the depolymerized chains. This study provides valuable information on the GlcNAc bioproduction from chitin using an enzymatic approach, addressing the key points for its production, including the enzyme cocktail composition and the substrate structures.


Assuntos
Acetilglucosamina/biossíntese , Aeromonas caviae/enzimologia , Quitina/metabolismo , Quitinases/metabolismo , Meios de Cultura/química , Concentração de Íons de Hidrogênio , Hidrólise , Espectroscopia de Ressonância Magnética , Peso Molecular , Temperatura Ambiente , Viscosidade , Difração de Raios X
8.
World J Microbiol Biotechnol ; 35(8): 121, 2019 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-31332590

RESUMO

The economics of bioflocculant production is coupled with the use of a low-cost substrate at appropriate culture conditions. The use of a waste substrate for this purpose offers an additional treatment measure to mitigate environmental pollution. We investigated the growth of Aspergillus flavus and its bioflocculant yield using chicken viscera hydrolysate as the sole media. The effects of culture conditions including time, pH, shaker speed, temperature and inoculum size on bioflocculant production were all investigated and optimised through response surface method based on the central component design (CCD) package of Design Expert. Next, the purified bioflocculant was physically and chemically characterised. Under optimised culture conditions (incubation time 72 h, pH 7, shaker speed 150 rpm, temperature 35 °C and inoculum 4%), 6.75 g/L yield of crude bioflocculant was recorded. The bioflocculant activity was mostly distributed in the cell-free supernatant with optimum efficiency of 91.8% at a dose of 4 mL/100 mL Kaolin suspension. The purified bioflocculant was a glycoprotein consisting of 23.46% protein and 74.5% sugar, including 46% neutral sugar and 2.01% uronic acid. The X-ray photoelectron spectroscopy fundamental analysis of the purified bioflocculant indicated that the mass proportion of C, O and N, were 63.46%, 27.87% and 8.86%, respectively. The bioflocculant is mainly composed of carbonyl, amino, hydroxyl, and amide functional groups. This study for the first time indicates a high potential of bioflocculant yield from chicken viscera at the appropriate culture conditions.


Assuntos
Aspergillus flavus/metabolismo , Meios de Cultura/química , Animais , Galinhas , Glicoproteínas/metabolismo , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Varredura , Espectroscopia Fotoeletrônica , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura Ambiente , Vísceras
9.
J Microbiol Biotechnol ; 29(7): 1061-1070, 2019 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-31280522

RESUMO

In the present study, the optimization of poly(γ-glutamic acid) (γ-PGA) production by Bacillus sp. FBL-2 was studied using a statistical approach. One-factor-at-a-time method was used to investigate the effect of carbon sources and nitrogen sources on γ-PGA production and was utilized to select the most significant nutrients affecting the yield of γ-PGA. After identifying effective nutrients, response surface methodology with central composite design (CCD) was used to obtain a mathematical model to identify the optimum concentrations of the key nutrients (sucrose, L-glutamic acid, yeast extract, and citric acid) for improvement of γ-PGA production. The optimum amount of significant medium components appeared to be sucrose 51.73 g/l, L-glutamic acid 105.30 g/l, yeast extract 13.25 g/l, and citric acid 10.04 g/l. The optimized medium was validated experimentally, and γ-PGA production increased significantly from 3.59 g/l (0.33 g/l/h) to 44.04 g/l (3.67 g/l/h) when strain FBL-2 was cultivated under the optimal medium developed by the statistical approach, as compared to non-optimized medium.


Assuntos
Bacillus/metabolismo , Ácido Poliglutâmico/análogos & derivados , Análise de Variância , Ácido Cítrico , Meios de Cultura/química , Fermentação , Ácido Glutâmico , Modelos Teóricos , Nitrogênio , Ácido Poliglutâmico/biossíntese , Projetos de Pesquisa , Sacarose
10.
World J Microbiol Biotechnol ; 35(7): 110, 2019 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-31280381

RESUMO

Carbon sources whether types or magnitudes were fateful in terms of stimulating growth and lipids accumulation in microalgae applied for biodiesel production. The set scenario of this work was to investigate the feasibilities of glucose (G) combining with sodium acetate (SA) carbon sources in enhancing biomass and lipid accumulation in Coccomyxa subellipsoidea. The results demonstrated that C. subellipsoidea subjected to the combination feeding of G (20 g/L) and SA (12 g/L) achieved the favorable biomass (5.22 g/L) and lipid content (52.16%). The resulting lipid productivity (388.96 mg/L/day) was 1.33- to 7.60-fold more than those of sole G or SA as well as other combinations of G and SA. Even though the total fatty acids of C. subellipsoidea cells treated with the optimal combination of G and SA showed no noticeable increment in comparison with sole G or SA, the proportion of monounsaturated C18:1 (over 48.69%) and the content of C18:3 (< 12%) were commendable in high-quality algal biodiesel production. Further, such fascinating lipid accumulation in C. subellipsoidea cells treated with G combining with SA might be attributed to that G promoted glycolysis as well as SA activated glyoxylate shunt and TCA cycle to synergistically provide sufficient acetyl-CoA precursors for lipid accumulation. These findings hinted the potential of the combination of carbon sources in enhancing the overall lipid productivity to offset alga-based biodiesel production cost and would guide other alga strains cultivation.


Assuntos
Clorófitas/crescimento & desenvolvimento , Clorófitas/metabolismo , Glucose/metabolismo , Lipídeos/biossíntese , Acetato de Sódio/metabolismo , Biocombustíveis , Biomassa , Carbono/metabolismo , Clorófitas/citologia , Meios de Cultura/química , Ácidos Graxos/biossíntese , Metabolômica , Microalgas/crescimento & desenvolvimento , Microalgas/metabolismo , Nitrogênio/metabolismo
11.
J Med Microbiol ; 68(9): 1269-1278, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31237536

RESUMO

Purpose. Increasing consumption of colistin as treatment for infections with multidrug-resistant (MDR) Gram-negative bacilli (GNB) has been accompanied by increasingly frequent reports of colistin-resistant (ColR) MDR GNB. Higher selective pressure creates a favourable environment that can facilitate the spread of ColR isolates. Monitoring of asymptomatic ColR GNB carriage can give us a better understanding of this emerging healthcare problem, particularly in wards with higher polymyxin selective pressure and prevalence of carbapenem-resistant GNB. Our aim was to assess the ColR GNB colonization rate in intensive care unit (ICU) patients and evaluate the performance of two surveillance protocols using a selective medium.Methodology. A prospective study included 739 surveillance samples (rectal swabs and tracheal aspirates) from 330 patients that were screened for ColR GNB carriage using SuperPolymyxin medium. Two approaches were used: direct sample plating and overnight pre-enrichment of samples followed by plating. Colistin resistance was confirmed with broth microdilution. ColR isolates were molecularly screened for plasmid-mediated mcr genes.Results. A total of 44/739 samples (45 ColR GNB isolates) were positive for ColR GNB, which included 31/330 (9.4 %) colonized patients; mcr genes were not detected. The direct plating method only identified 17/45 (37.8 %) isolates correctly, whereas the pre-enrichment protocol identified all 45 ColR GNB.Conclusion. The colonization rate among our ICU patients was 9.4  %. Based on our findings, the pre-enrichment step is necessary for the determination of ColR GNB carriage - even though the time to result takes an additional day, fewer than half of ColR GNB carriers were detected using the direct plating protocol.


Assuntos
Antibacterianos/farmacologia , Técnicas Bacteriológicas/métodos , Portador Sadio/diagnóstico , Colistina/farmacologia , Farmacorresistência Bacteriana , Bactérias Gram-Negativas/isolamento & purificação , Infecções por Bactérias Gram-Negativas/diagnóstico , Portador Sadio/epidemiologia , Portador Sadio/microbiologia , Meios de Cultura/química , Monitoramento Epidemiológico , Genes Bacterianos , Técnicas de Genotipagem , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/crescimento & desenvolvimento , Infecções por Bactérias Gram-Negativas/epidemiologia , Infecções por Bactérias Gram-Negativas/microbiologia , Humanos , Unidades de Terapia Intensiva , Plasmídeos/análise , Prevalência , Estudos Prospectivos , Reto/microbiologia , Traqueia/microbiologia
12.
Prep Biochem Biotechnol ; 49(8): 813-821, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31169457

RESUMO

Separation of biomass from culture media by centrifugation and then washing the biomass are mandatory steps in the fermentation process of recombinant Pichia pastoris expressed HBsAg intracellularly. Biomass has to be washed many times to eliminate the culture media residues thoroughly. In this study, we tried to develop the hydrocyclone as an alternative method for separation of biomass from fermentation culture, an attractive replacement for centrifugation processes. The advantages of using hydrocyclone in biomass separation could be summarized in its suitability for continuous separation and its low risk of contamination. To evaluate the performance of hydrocyclone, concentration ratio in underflow to feed stream, capacity, and centrifugal force by considering three parameters of pressure drop, concentration, and the type of hydrocyclone were investigated. Using three level factorial design a concentration ratio equation was developed, with the correlation coefficient R2 = 0.977 ensured the good fitness of the predicted data with the experimental results. In optimal conditions, maximum concentration ratio was 1.246, for flow rate 13.5 LPM and C-force equal to 1276.11 at maximum pressure drop (3 bar) and minimum concentration (0.5% w/w) in hydrocyclone 1. Herein, two different hydrocyclones with the cylindrical diameters of 19 mm and 21 mm were used for separating the yeast cells.


Assuntos
Centrifugação/instrumentação , Meios de Cultura/química , Antígenos de Superfície da Hepatite B/isolamento & purificação , Pichia/química , Técnicas de Cultura Celular por Lotes/instrumentação , Biomassa , Desenho de Equipamento , Fermentação , Pressão , Proteínas Recombinantes/isolamento & purificação
13.
Klin Lab Diagn ; 64(6): 360-367, 2019.
Artigo em Russo | MEDLINE | ID: mdl-31200409

RESUMO

The results of the comparative tests of the «Agar Muller-Hinton II - Obolensk¼ nutrient medium developed in SRCAMB, Obolensk, and the control nutrient medium imported «Mueller Hinton II Agar¼ are presented in the study. The susceptibility of bacterial clinical strains to antimicrobial agents (AMP) was determined by the disc diffusion method and the method of gradient diffusion (E-test). The carbapenemase activity of the strains carrying the carbapenemase genes was determined by CIM-test. Total 173 characterized bacterial strains of species Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, Proteus mirabilis, Serratia marcescens, Enterobacter aerogenes, Escherichia coli; Photorhabdus spp., Staphylococcus aureus, Enterococcus spp. were used in the study, including producers of OXA- and NDM-types carbapenemases for gram negative bacteria. A high degree of coincidence of the results obtained on both nutrient media was shown. The consistency index of the strain sensitivity categories to AMPs (S, I, and R) was 98.2% for the disc diffusion method, and 94.4-100% - for E-test and CIM-test methods. Thus, within the framework of the Import Substitution Program, the domestic nutrient medium «MHA II-Obolensk¼ has been successfully developed. The nutrient medium meets the requirements of GOST R ISO 20776-2-2010 «Clinical laboratory testing and in vitro diagnostic test systems - Susceptibility testing of infectious agents and evaluation of performance of antimicrobial susceptibility test devices¼.


Assuntos
Ágar/química , Antibacterianos/farmacologia , Meios de Cultura/química , Testes de Sensibilidade Microbiana
14.
J Dairy Sci ; 102(8): 6781-6789, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31155253

RESUMO

Selenium is included in selenoprotein sequences, which participate in enzymatic processes necessary to preserve optimal health. Some lactic acid bacteria carry out the biotransformation of inorganic selenium in their metabolism. The complete biochemical mechanism of selenium biotransformation is still unknown; however, it is known that both the selenocysteine synthesis process and its subsequent incorporation into selenoproteins include serine as part of the action of seryl-RNAt synthetase. Therefore, the aim of this work was to determine the effect of serine during the biotransformation of selenium and the subsequence growth of Streptococcus thermophilus in a minimal medium. Two culture media were prepared, one enriched with the minimum inhibitory concentration of selenite (as Na2SeO3) and the other as a mixture of the minimum inhibitory concentration of selenite and serine. The absorbed selenium concentration was measured by inductively coupled plasma, and the selenocysteine identification was performed by reverse-phase HPLC. In the second culture medium, decreases in both times, the adaptation and the logarithmic phase, were observed. According to the results, it was possible to establish that the presence of serine allowed the biotransformation of selenite into selenocysteine by Strep. thermophilus.


Assuntos
Meios de Cultura/química , Selênio/metabolismo , Selenocisteína/biossíntese , Serina/administração & dosagem , Streptococcus thermophilus/metabolismo , Animais , Cromatografia Líquida de Alta Pressão , Selenoproteínas , Serina/análise
15.
J Microbiol Biotechnol ; 29(6): 933-943, 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31154752

RESUMO

Gamma-aminobutyric acid (GABA)-producing strains were isolated from four edible insects and subjected to 16S rRNA sequence analysis. Among the four GABA-producing bacteria, Enterococcus avium JS-N6B4 exhibited the highest GABA-production, while cultivation temperature, initial pH, aerobic condition, and mono-sodium glutamate (MSG) feeding were found to be the key factors affecting GABA production rate. The culture condition was optimized in terms of glucose, yeast extract, and MSG concentrations using response surface methodology (RSM). GABA production up to 16.64 g/l was obtained under the conditions of 7 g/l glucose, 45 g/l yeast extract, and 62 g/l MSG through the optimization of medium composition by RSM. Experimental GABA production was 13.68 g/l, which was close to the predicted value (16.64 g/l) calculated from the analysis of variance, and 2.79-fold higher than the production achieved with basic medium. Therefore, GABA-producing strains may help improve the GABA production in edible insects, and provide a new approach to the use of edible insects as effective food biomaterials.


Assuntos
Enterococcus/metabolismo , Microbiologia de Alimentos , Insetos/microbiologia , Ácido gama-Aminobutírico/biossíntese , Animais , Meios de Cultura/química , DNA Bacteriano/genética , Enterococcus/classificação , Enterococcus/genética , Enterococcus/crescimento & desenvolvimento , Concentração de Íons de Hidrogênio , Nutrientes/química , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Glutamato de Sódio/química , Glutamato de Sódio/metabolismo , Temperatura Ambiente
16.
J Food Sci ; 84(7): 1776-1783, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31218715

RESUMO

Citrus pectin hydrolysates (Citrus paradisi [Mafc.]) from "Foster," "Red Shambar," "Tangelo Orlando," and "Citrumelo Swingle" cultivars were obtained by partial chemical hydrolysis and their properties as culture media (sole carbon/nutrient source) and encapsulating agents of Lactobacillus plantarum CIDCA 83114 were evaluated. The concentration of neutral sugars was maximal after 2-hour hydrolysis. All hydrolysates were rich in glucose >xylose >galactose >galacturonic acid >mannose >arabinose. "Citrumelo Swingle" cultivar was the one with the highest concentration of xylose. After 24 hr of fermentation with L. plantarum CIDCA 83114, bacterial viability increased from 6.76 ± 0.14 to almost 9 log CFU/mL, and lactic acid concentration, from 2.63 ± 0.41 to 7.82 ± 0.15 mmol/L in all hydrolysates. Afterwards, bacteria were entrapped in pectate-calcium beads by ionotropic gelation. Bacterial viability did not significantly decrease after freeze-drying and storage the beads at 4 °C for 45 days. PRACTICAL APPLICATION: Pectin hydrolysates were adequate culture media for microorganisms, as determined by the viabililty and lactic acid production. Considering that citrus peels are agro-wastes obtained in large quantities, their use as encapsulating materials provides a solution to overcome the environmental problem they entail.


Assuntos
Citrus paradisi/química , Meios de Cultura/metabolismo , Lactobacillus plantarum/química , Pectinas/química , Citrus paradisi/metabolismo , Meios de Cultura/química , Fermentação , Liofilização , Hidrólise , Ácido Láctico/análise , Ácido Láctico/metabolismo , Lactobacillus plantarum/classificação , Lactobacillus plantarum/crescimento & desenvolvimento , Lactobacillus plantarum/metabolismo , Pectinas/metabolismo , Açúcares/análise , Açúcares/metabolismo
17.
BMC Vet Res ; 15(1): 133, 2019 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-31064357

RESUMO

BACKGROUND: Burkholderia mallei is a Gram-negative bacterium that causes glanders, a zoonotic disease, especially in equine populations (e.g. horses, donkeys, and mules). B. mallei usually grows slowly on most culture media, and this property makes it difficult to isolate from clinical specimens. One of the problems is that B. mallei is easily overgrown by other bacteria, especially in animal specimens collected from non-sterile sites. The aim of this study was to develop a new selective agar for the laboratory diagnosis of glanders. We formulated a new agar, named BM agar, to enrich B. mallei growth, but inhibit the growth of other bacteria and fungi based on their antimicrobial profiles. We compared the growth of B. mallei on BM with Xie's and PC agars, the two previously described selective agars for B. mallei. RESULTS: BM agar could sufficiently grow almost all of the tested B. mallei strains within 72 h: only one out of the 38 strains grew scantly after 72 h of incubation. BM agar was further tested with other Burkholderia species and various bacterial species commonly found in the nasal cavities and on the skin of horses. We have found that other Burkholderia species including B. pseudomallei and B. thailandensis can grow on BM agar, but non-Burkholderia species cannot. Furthermore, the specificities of the three selective agars were tested with or without spiking B. mallei culture into clinical specimens of non-sterile sites collected from healthy horses. The results showed that BM agar inhibited growths of fungi and other bacterial species better than PC and Xie's agars. We have also found that growth of B. mallei on BM agar was equivalent to that on 5% horse blood agar and was significantly greater than those on the other two agars (P < 0.05). CONCLUSIONS: We believe that BM agar can be used to efficiently isolate B. mallei from mixed samples such as those typically collected from horses and other contaminated environments.


Assuntos
Burkholderia mallei/isolamento & purificação , Meios de Cultura/química , Mormo/diagnóstico , Mormo/microbiologia , Ágar , Animais , Burkholderia mallei/crescimento & desenvolvimento , Cavalos
18.
An Acad Bras Cienc ; 91(2): e20180333, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31038537

RESUMO

Abstract: The present work investigated what the appropriate methods of hydrolysis of pectin for reducing compounds (RCs) production, employed as a substrate for cell growth of Cupriavidus necator. This microorganism has great importance industrial, because besides potential single cell protein (SCP), is the most studied microorganism for production of polyhydroxybutyrate (PHB), and both processes require high cell concentration with inexpensive substrates For this, it was compared to acid and enzymatic hydrolysis procedures, through rotational central composite experimental design, using pectin concentration (1.0%). It was analyzed as a variable response for both experimental design, the RCs' production. The best conditions of each procedure were used in study kinetics of RCs' production and as a substrate for cell growth of C. necator. The results indicated that the enzymatic hydrolysis method was the most efficient, with a 93.0% yield of RCs, while the yield for acid hydrolysis was 60.0%. The optimum conditions for enzymatic hydrolysis were an enzyme concentration of 10.01 UI/g (International Unit of enzyme per gram of pectin) and an agitation speed of 230.3 rpm. C. necator showed satisfactory growth in the media containing pectin hydrolysates, with specific growth rates (µMax) similar to those reported for other substrates.


Assuntos
Meios de Cultura/química , Cupriavidus necator/crescimento & desenvolvimento , Pectinas/química , Análise de Variância , Técnicas de Cultura de Células/métodos , Proliferação de Células/fisiologia , Ácidos Hexurônicos/química , Hidrólise , Cinética , Valores de Referência , Reprodutibilidade dos Testes , Espectrofotometria/métodos , Temperatura Ambiente , Fatores de Tempo
19.
Mol Med Rep ; 19(6): 5123-5132, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31059024

RESUMO

Human amniotic fluid (hAF) mesenchymal stem cells (MSCs) are commonly cultured in medium containing FBS. However, there are concerns about using animal serum in therapeutic applications due to the potential for immunogenic reactions and the risk of transmission of pathogens. For safety reasons, human platelet lysate (hPL) has been suggested as a replacement for FBS because it appears to be a natural source of growth factors. In this present study, it was investigated whether FBS could be substituted with hPL in hAF­MSCs culture without affecting their properties. Pooled hPL was generated by the freeze­thaw method. The concentration of hPL was selected after evaluation by MTT assay. The hAF­MSCs were cultured in FBS­ or hPL­supplemented conditions and shared a fibroblast­like morphology. Cell proliferation assays showed that the growth characteristic of hAF­MSCs cultured in 10% hPL­supplemented media was similar to those cultured in 10% FBS­supplemented media. The expression of MSC markers did not differ between the cells cultured in the different conditions. The endothelial differentiation potential was also investigated. Reverse transcription­quantitative (RT­q)PCR revealed that induced cells supplemented with hPL showed an increase level of endothelial specific gene expression compared to the FBS­supplemented cells. Immunofluorescence analysis showed specific protein localization in both induced cell groups. Additionally, induced cells supplemented with hPL had the potential to form networks on Matrigel. This present study indicated that hPL could be used to culture and enhance the endothelial differentiation potential of hAF­MSCs.


Assuntos
Líquido Amniótico/citologia , Plaquetas/metabolismo , Diferenciação Celular , Meios de Cultura/química , Células-Tronco Mesenquimais/citologia , Animais , Plaquetas/química , Bovinos , Técnicas de Cultura de Células/métodos , Proliferação de Células , Células Cultivadas , Humanos , Células-Tronco Mesenquimais/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Soro/química , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Fator de von Willebrand/metabolismo
20.
Appl Microbiol Biotechnol ; 103(12): 5015-5022, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31044312

RESUMO

Old Yellow Enzymes play key roles in several cellular processes and have become an important family of enzymes with biotechnological potential. One of the major challenges of biotechnology consists of the bioremediation of co-polluted soils with organic and inorganic compounds. In co-contaminated areas, chromium normally exists in its more toxic and carcinogenic form Cr(VI). Microorganisms can reduce this metal to the insoluble and less toxic Cr(III). Streptomyces sp. M7 is a strain able to efficiently bioremediate polluted soils with γ-hexachlorocyclohexane and Cr(VI). The complete degradation pathway for γ-hexachlorocyclohexane was recently elucidated in this strain. In the present work, we confirmed the ability of Streptomyces sp. M7 to eliminate a high percentage of Cr(VI) from a synthetic culture medium. After a transcriptional study in the presence of Cr(VI), we also report the molecular cloning of a gene coding for an Old Yellow Enzyme with chromate reductase activity. Our results suggest that the elimination of Cr(VI) by Streptomyces sp. M7 is directly related to the activity of this Old Yellow Enzyme. The importance of our work is in identifying for the first time an Old Yellow Enzyme with chromate reductase activity in Streptomyces and Actinobacteria. Finding this enzyme helps understand chromium homeostasis in Streptomyces sp. M7, in addition to opening a new research window related to Old Yellow Enzymes from Actinobacteria.


Assuntos
Biodegradação Ambiental , Cromo/metabolismo , Meios de Cultura/química , NADPH Desidrogenase/metabolismo , Streptomyces/enzimologia , Redes e Vias Metabólicas , NADPH Desidrogenase/genética , Oxirredução , Oxirredutases/metabolismo , Microbiologia do Solo , Streptomyces/genética
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