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1.
Food Chem ; 370: 130996, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34520975

RESUMO

The quality and formation of bioactive components in fermented koumiss are based on the complex metabolism of the microbial community. In the present study, changes in the bioactive metabolites and microbial communities in black and white horse-sourced koumiss were evaluated during the fermentation process. 74 and 69 differential metabolites were formed when BLM and WHM were fermentated into koumiss. Lactobacillus and Dekkera grew rapidly and became the dominant genera in the koumiss. Bioactive compounds (e.g., adenine, d-proline) were significantly enhanced after natural fermentation and were positively correlated with Lactobacillus, Dekkera and Acetobacter. The microbial metabolic network showed that Lactobacillus and Dekkera were the functional core microbiota and played significant roles in the formation of bioactive compounds, followed by Acetobacter, Streptococcus and Leuconostoc. The current study results provide new insight into the formation of bioactive components in koumiss, which is useful for directionally isolating functional microorganisms suitable for koumiss fermentation.


Assuntos
Kumis , Microbiota , Fermentação , Lactobacillus , Metabolômica
2.
Food Res Int ; 149: 110659, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34600661

RESUMO

Koumiss, naturally fermented mare's milk, has a unique flavor that is affected by its resident microflora. In this study, we analyzed time-dependent changes in the microbiota and volatile metabolite profiles of koumiss using high-throughput sequencing and liquid-liquid extraction-gas chromatography-mass spectrometry. The dominant microrganisms in mare milk were Enterobacter and Rhodotorula, which were gradually suppressed, then Lactobacillus and Dekkera became the core microorganisms of koumiss. 17 FAA and 52 volatile organic compounds (VOCs) were identified during koumiss fermentation, including 19 odor active compounds and 15 differential metabolites of VOCs, mainly acids and esters, and their anabolism showed significant positive correlations with Lactobacillus and Dekkera. The microbial metabolic network showed that Lactobacillus and Dekkera were identified as the most important flavor-producing microbiota due to their significantly positive correlation with the formation of 33 and 28 flavor metabolites, respectively. These microorganisms produce enzymes that catalyze a series of metabolic pathways that generate VOCs, including carbohydrate metabolism, amino acid metabolism, and fatty acid biosynthesis. Our findings provide new guidance for the screening and application of flavor-producing microorganisms inkoumiss.


Assuntos
Kumis , Animais , Feminino , Fermentação , Aromatizantes , Cavalos , Redes e Vias Metabólicas , Paladar
3.
FASEB J ; 35(9): e21777, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34403519

RESUMO

Mycobacterium bovis is the causative agent of bovine tuberculosis and also responsible for serious threat to public health. Koumiss is a fermented mare's milk product, used as traditional drink. Here, we explored the effect of koumiss on gut microbiota and the host immune response against M bovis infection. Therefore, mice were treated with koumiss and fresh mare milk for 14 days before M bovis infection and continue for 5 weeks after infection. The results showed a clear change in the intestinal flora of mice treated with koumiss, and the lungs of mice treated with koumiss showed severe edema, inflammatory infiltration, and pulmonary nodules in M bovis-infected mice. Notably, we found that the content of short-chain fatty acids was significantly lower in the koumiss-treated group compared with the control group. However, the expression of endoplasmic reticulum stress and apoptosis-related proteins in the lungs of koumiss-treated mice were significantly decreased. Collectively, these findings suggest that koumiss treatment disturb the intestinal flora of, which is associated with disease severity and the possible mechanism that induces lungs pathology. Our current findings can be exploited further to establish the "gut-lung" axis which might be a novel strategy for the control of tuberculosis.


Assuntos
Estresse do Retículo Endoplasmático/efeitos dos fármacos , Microbioma Gastrointestinal/efeitos dos fármacos , Kumis/efeitos adversos , Mycobacterium bovis/efeitos dos fármacos , Tuberculose Pulmonar/microbiologia , Tuberculose Pulmonar/patologia , Animais , Apoptose/efeitos dos fármacos , Modelos Animais de Doenças , Ácidos Graxos/análise , Fezes/química , Fezes/microbiologia , Feminino , Microbioma Gastrointestinal/imunologia , Cavalos , Pulmão/efeitos dos fármacos , Pulmão/microbiologia , Pulmão/patologia , Camundongos , Camundongos Endogâmicos BALB C , Mycobacterium bovis/imunologia , Tuberculose Pulmonar/dietoterapia , Tuberculose Pulmonar/metabolismo
4.
Pol J Vet Sci ; 24(2): 167-173, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34250775

RESUMO

Koumiss has beneficial therapeutic effects on bacterial diseases. Four antibacterial com- pounds from yeasts (Kluyveromyces marxianus and Saccharomyces cerevisiae) in koumiss were evaluated for their antibacterial effects against three Gram-negative bacteria, three Gram-positive bacteria and five pathogenic Escherichia coli strains. The antibacterial compounds from yeasts in koumiss were extracted, and their main components were determined. The inhibition zones were analyzed, and their minimum inhibition concentrations (MICs) and minimum bactericidal concentrations (MBCs) were determined. Aqueous phases of Kluyveromyces marxianus and Saccharomyces cerevisiae at pH 2.0 and 8.0 produced larger inhibition zones than those in other phases, and then antibacterial compounds from K. marxianus (K2, pH=2.0; K8, pH=8.0) and S. cerevisiae (S2, pH=2.0; S8, pH=8.0) were obtained. Their main components were organic acids and killer toxins. K2 had more propanoic acid and S2 had more oxalic acid than others. The inhibition zones of K2, K8, S2 and S8 against three Gram-negative bacteria and three Gram-positive bacteria were 12.03-23.30 mm, their MICs were 0.01-0.13 g/mL, and MBCs were 0.03-0.50 g/mL. Meantime, the inhibition zones of K2, K8, S2 and S8 against five pathogenic E. coli were 16.10-25.26 mm, their MICs were 0.03-0.13 g/mL, and MBCs were 0.13-1.00 g/mL. These four antibacterial compounds from yeasts in koumiss had broad antibacterial spectrum. In addition, K2 and S2 were better than K8 and S8.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Kumis/microbiologia , Leveduras/metabolismo , Antibacterianos/química , Leveduras/química
5.
Folia Microbiol (Praha) ; 66(5): 855-871, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34191226

RESUMO

A bacteriocin termed plantaricin MX with a broad antimicrobial spectrum was produced by Lactobacillus plantarum NMD-17, which was isolated from Inner Mongolia traditional koumiss of china. Among 300 strains of lactic acid bacteria (LAB) belonging to the genera Lactococcus, Lactobacillus, Streptococcus, Leuconostoc, and Enterococcus, five strains including Lactobacillus reuteri NMD-86, Lactobacillus helveticus NMD-137, Lactococcus lactis NMD-152, Enterococcus faecalis NMD-178, and Enterococcus faecium NMD-219 were revealed to significantly induce the bacteriocin synthesis and greatly increase the cell numbers of Lactobacillus plantarum NMD-17 and activity of AI-2 signaling molecule. Bacteriocin synthesis was not increased by cell-free supernatants and autoclaved cultures of inducing strains, demonstrating that intact cells of inducing strains were essential to the induction of bacteriocin synthesis. The existence of bacteriocin structural plnEF genes and the plnD and luxS genes involved in quorum sensing was confirmed by PCR, and the presence of plnB gene encoding histidine protein kinase was determined by single oligonucleotide nested PCR (Son-PCR). Quantitative real-time PCR demonstrated that plnB, plnD, luxS, plnE, and plnF genes of L. plantarum NMD-17 were upregulated significantly (P < 0.01) in co-cultivation with L. reuteri NMD-86. The results showed that the bacteriocin synthesis of L. plantarum NMD-17 in co-cultivation might have a close relationship with LuxS-mediated quorum sensing system.


Assuntos
Proteínas de Bactérias , Bacteriocinas , Liases de Carbono-Enxofre , Kumis , Lactobacillales , Lactobacillus plantarum , Interações Microbianas , Proteínas de Bactérias/genética , Bacteriocinas/genética , Liases de Carbono-Enxofre/genética , Kumis/microbiologia , Lactobacillales/fisiologia , Lactobacillus plantarum/genética , Interações Microbianas/fisiologia , Percepção de Quorum/genética
6.
J Dairy Sci ; 104(1): 151-166, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33162079

RESUMO

Koumiss is a type of famous fermented mare milk and considered an important nutritious beverage in central Asian countries. However, the production of koumiss cannot meet public demand in the market due to availability of mare milk. In the present study, 52 lactic acid bacteria and 20 yeast strains from traditional homemade Kazakhstan koumiss were isolated and identified. The isolates were used in a trial that included fermented cow milk, and the flavor profiles, color, and taste to determine their contribution in the co-fermentation of cow milk. Based on the sensory evaluation, KZLAB13 and KZY10 strains were selected as the best cofermentation combinations. The optimal fermentation conditions were confirmed as the ratio of the starter culture 2.4:1.6 % (vol/vol) KZLAB13 strain to KZY10 strain and a temperature of 36°C for 16 h using response surface methodology. After evaluating the quality of the optimized cow-milk koumiss compared with the Kazakhstan koumiss, results suggested that cow milk fermented by these 2 strains possessed a promising taste, flavor, and physicochemical and rheological properties. Altogether, our results showed that cow milk fermented with a combination of KZLAB13 and KZY10 strains can simulate the taste, flavor, and quality of traditional koumiss. Our study provided a novel alternative to mare-milk koumiss and could be used in dairy programs to fulfill the needs of people.


Assuntos
Kumis/microbiologia , Lactobacillales/metabolismo , Leite/microbiologia , Animais , Bovinos , Feminino , Fermentação , Cavalos , Cazaquistão , Lactobacillales/isolamento & purificação , Leite/metabolismo , Paladar , Leveduras/isolamento & purificação
7.
BMC Microbiol ; 20(1): 85, 2020 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-32276583

RESUMO

BACKGROUND: Koumiss is a naturally fermented mare's milk. Over recent decades, numerous studies have revealed the diversity of lactic acid bacteria in koumiss. However, there is limited information available regarding its secondary major component yeast profile. RESULTS: A total of 119 bacterial and 36 yeast species were identified among the 14 koumiss samples. The dominant bacterial species in koumiss were Lactobacillus helveticus, Lactobacillus kefiranofaciens, Lactococcus lactis, Lactococcus raffinolactis, and Citrobacter freundii. The main yeast species were Dekkera anomala, Kazachstania unispora, Meyerozyma caribbica, Pichia sp.BZ159, Kluyveromyces marxianus, and uncultured Guehomyces. The bacterial and yeast Shannon diversity of the Xilinhaote-urban group were higher than those of the Xilingol-rural group. The most dominant organic acids were lactic, acetic, tartaric, and malic acids. Lactic acid bacteria species were mostly responsible for the accumulation of those organic acids, although Kazachstania unispora, Dekkera anomala, and Meyerozyma caribbica may also have contributed. Redundancy analysis suggested that both bacteria and yeast respond to koumiss flavor, such as Lactobacillus helveticus and Dekkera anomala are associated with sourness, astringency, bitterness, and aftertaste, whereas Lactococcus lactis and Kazachstania unispora are associated with umami. CONCLUSIONS: Our results suggest that differences were observed in koumiss microbiota of Xilinhaote-urban and Xilingol-rural samples. The biodiversity of the former was higher than the latter group. Positive or negative correlations between bacteria and yeast species and taste also were found.


Assuntos
Ácidos/análise , Bactérias/classificação , Kumis/microbiologia , Leveduras/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Biodiversidade , Fermentação , Kumis/análise , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Paladar , Leveduras/genética , Leveduras/isolamento & purificação
8.
Food Chem ; 320: 126619, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32203836

RESUMO

The fermentation of mare's milk into koumiss produces many beneficial functional compounds depending on the metabolism of the initial microbial flora. In this study, metabolites found in mare's milk and resulting koumiss were identified. Major metabolic pathways in the fermentation were also identified using an UPLC-Q-TOF-MS-based metabolomics method. In total, 354 metabolites were identified: 61 were up-regulated and 105 were down-regulated. Metabolic pathway analyses revealed that c-5-branched dibasic acid metabolism, valine, leucine and isoleucine degradation, arginine and proline metabolism, valine, leucine and isoleucine biosynthesis, vascular smooth muscle contraction, aminoacyl-tRNA biosynthesis and ß-alanine metabolism showed significant increases. A hierarchical cluster analysis of metabolites indicated a clear grouping pattern in which the relative concentrations of p-pyruvate, 20-HETE, 4-aminobutanoate, uracil, acetoacetate, and γ-linolenic acid differed significantly between milk and koumiss. This study provides reference values for metabolic isolates and bioactive compounds purification in mare's milk and koumiss.


Assuntos
Kumis/análise , Metabolômica , Leite/química , Animais , Arginina/química , Arginina/metabolismo , Cromatografia Líquida de Alta Pressão , Feminino , Fermentação , Cavalos , Leucina/química , Leucina/metabolismo , Espectrometria de Massas , Leite/metabolismo , Valina/química , Valina/metabolismo
9.
J Sci Food Agric ; 100(4): 1822-1826, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31858597

RESUMO

BACKGROUND: Koumiss is a traditional fermented beverage made from mare's milk. The traditional backslopping method for koumiss production has shortcomings in terms of microbiological diversity and nutritional characteristics. In this study, a two-stage fermentation method was established to scale up the production of koumiss powder. The chemical composition and nutritional properties of a novel two-stage fermentation koumiss powder (TKP) were compared with backslopping koumiss powder (BKP). RESULTS: The TKP exhibited important nutritional and functional properties, including a high percentage of essential amino acids, and high polyunsaturated fatty acid, vitamin, and mineral content. The essential amino acid content of TKP was not significantly different from that of BKP. The oleic acid, linoleic acid, linolenic acid, and water-soluble vitamin content of TKP was higher than that of BKP. The Ca:P ratio of TKP was also close to the optimal Ca:P ratio in humans. CONCLUSION: The novel method could be applied for the scaled-up production of koumiss powder with similar nutritional properties to traditional backslopping koumiss powder. The successful production of koumiss powder could also promote the development of the koumiss industry. © 2019 Society of Chemical Industry.


Assuntos
Microbiologia de Alimentos/métodos , Kumis/análise , Leite/microbiologia , Pós/química , Aminoácidos/análise , Animais , Fermentação , Cavalos , Kumis/microbiologia , Lactobacillaceae/metabolismo , Leite/química , Minerais/análise , Valor Nutritivo , Vitaminas/análise
10.
Colloids Surf B Biointerfaces ; 186: 110734, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31865119

RESUMO

Recently, silver nanoparticles gain significant attention due to their applications in various fields. The aim of present study was to develop the eco-friendly, cost effective, and simple method to biosynthesized the silver nanoparticle using sliver nitrate as precursor. In this study, we investigated the physical characterization and biotechnological applications of biosynthesized silver nanoparticle using exopolysaccharide of probiotic Lactobacillus brevis MSR104 isolated from Chinese koumiss. Biosynthesized silver nanoparticles were characterized using the fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, and elemental analyzer. The achieved results indicate that silver nanoparticles varied in sized with an average size of 45 nm. The X-ray diffraction analysis results showed that the silver nanoparticles have a crystalline nature. The results of antimicrobial assay indicated that the silver nanoparticles exhibited outstanding antimicrobial activity in dose dependent manner against both Gram's negative as well as Gram's positive. The antioxidant results indicate that the silver nanoparticles showed excellent scavenging rate against DPPH free radicals (81.4 ±â€¯1.2%) and nitric oxide free radicals (75.06 ±â€¯0.4%). Furthermore, the results of MTT assay revealed that the AgNPs significantly reduced the percentage of live HT-29 cells at higher concentration. This study concluded that the newly synthesized silver nanoparticles have antibacterial, antioxidant, and anticancer applications in agricultural and food industries.


Assuntos
Antibacterianos/farmacologia , Antioxidantes/farmacologia , Kumis/microbiologia , Lactobacillus brevis/metabolismo , Polissacarídeos/farmacologia , Antibacterianos/biossíntese , Antibacterianos/isolamento & purificação , Antioxidantes/isolamento & purificação , Antioxidantes/metabolismo , Compostos de Bifenilo/antagonistas & inibidores , China , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Lactobacillus brevis/química , Nanopartículas Metálicas/química , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Picratos/antagonistas & inibidores , Polissacarídeos/biossíntese , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Prata/química , Prata/metabolismo , Propriedades de Superfície
11.
J Dairy Sci ; 102(5): 3912-3923, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30852020

RESUMO

Traditional fermented dairy foods have been the major components of the Mongolian diet for millennia. In this study, we used propidium monoazide (PMA; binds to DNA of nonviable cells so that only viable cells are enumerated) and single-molecule real-time sequencing (SMRT) technology to investigate the total and viable bacterial compositions of 19 traditional fermented dairy foods, including koumiss from Inner Mongolia (KIM), koumiss from Mongolia (KM), and fermented cow milk from Mongolia (CM); sample groups treated with PMA were designated PKIM, PKM, and PCM. Full-length 16S rRNA sequencing identified 195 bacterial species in 121 genera and 13 phyla in PMA-treated and untreated samples. The PMA-treated and untreated samples differed significantly in their bacterial community composition and α-diversity values. The predominant species in KM, KIM, and CM were Lactobacillus helveticus, Streptococcus parauberis, and Lactobacillus delbrueckii, whereas the predominant species in PKM, PKIM, and PCM were Enterobacter xiangfangensis, Lactobacillus helveticus, and E. xiangfangensis, respectively. Weighted and unweighted principal coordinate analyses showed a clear clustering pattern with good separation and only minor overlapping. In addition, a pure culture method was performed to obtain lactic acid bacteria resources in dairy samples according to the results of SMRT sequencing. A total of 102 LAB strains were identified and Lb. helveticus (68.63%) was the most abundant, in agreement with SMRT sequencing results. Our results revealed that the bacterial communities of traditional dairy foods are complex and vary by type of fermented dairy product. The PMA treatment induced significant changes in bacterial community structure.


Assuntos
Azidas , Produtos Fermentados do Leite/microbiologia , Microbiota , Propídio/análogos & derivados , Análise de Sequência/métodos , Animais , Bactérias/classificação , Bovinos , China , DNA Bacteriano/análise , Feminino , Fermentação , Kumis , Lactobacillales/genética , Lactobacillus delbrueckii/genética , Lactobacillus helveticus/genética , Leite/microbiologia , Mongólia , RNA Bacteriano/análise , RNA Ribossômico 16S/análise , RNA Ribossômico 16S/química , RNA Ribossômico 16S/genética
12.
Folia Microbiol (Praha) ; 64(6): 821-834, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30895557

RESUMO

An agar well diffusion assay (AWDA) was used to isolate a high bacteriocin-producing strain with a broad spectrum of antibacterial activity, strain MXG-68, from Inner Mongolia traditional fermented koumiss. Lactobacillus plantarum MXG-68 was identified by morphological, biochemical, and physiological characteristics and 16S rDNA analysis. The production of antibacterial substance followed a growth-interrelated model, starting at the late lag phase of 4 h and arriving at a maximum value in the middle of the stationary phase at 24 h. Antibacterial activity was abolished or decreased in the presence of pepsin, chymotrypsin, trypsin, proteinase, and papain K. The results showed that antibacterial substances produced by L. plantarum MXG-68 were proteinaceous and could thus be classified as the bacteriocin, named plantaricin MXG-68. The molar mass of plantaricin MXG-68 was estimated to be 6.5 kDa, and the amino acid sequence of its N-terminal was determined to be VYGPAGIFNT. The mode of plantaricin MXG-68 action was determined to be bactericidal. Bacteriocin in cell-free supernatant (CFS) at pH 7 was stable at different temperatures (60 °C, 80 °C, 100 °C, 121 °C for 30 min; 4 °C and - 20 °C for 30 days), as well as at pH 2.0-10.0. Antibacterial activity maintained stable after treatment with organic solvents, surfactants, and detergents but increased in response to EDTA. Response surface methodology (RSM) revealed the optimum conditions of bacteriocin production in L. plantarum MXG-68, and the bacteriocin production in medium optimized by RSM was 26.10% higher than that in the basal MRS medium.


Assuntos
Antibacterianos/biossíntese , Bacteriocinas/biossíntese , Kumis/microbiologia , Lactobacillus plantarum/química , Sequência de Aminoácidos , Antibacterianos/química , Antibacterianos/farmacologia , Bacteriocinas/química , Bacteriocinas/farmacologia , China , Meios de Cultura , Microbiologia de Alimentos , Cinética , Lactobacillus plantarum/classificação , Lactobacillus plantarum/fisiologia , Peso Molecular , Filogenia , Estabilidade Proteica , RNA Ribossômico 16S/genética , Staphylococcus/efeitos dos fármacos
13.
J Dairy Sci ; 102(3): 1972-1984, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30639001

RESUMO

Koumiss is notable for its nutritional functions, and microorganisms in koumiss determine its versatility. In this study, the bacterial and fungal community structures in traditional koumiss from Inner Mongolia, China, were investigated. Our results demonstrated that 6 bacterial phyla represented by 126 genera and 49 species and 3 fungal phyla represented by 59 genera and 57 species were detected in 11 samples of artisanal koumiss. Among them, Lactobacillus was the predominant genus of bacterium, and Kluyveromyces and Saccharomyces dominated at the fungal genus level. In addition, there were no differences in the bacterial and fungal richness and diversity of koumiss from 3 neighboring administrative divisions in Inner Mongolia, and the bacterial and fungal community structures (the varieties and relative abundance of bacterial and fungal genera and species) were clearly distinct in individual samples. This study provides a comprehensive understanding of the bacterial and fungal population profiles and the predominant genus and species, which would be beneficial for screening, isolation, and culture of potential probiotics to simulate traditional fermentation of koumiss for industrial and standardized production in the future.


Assuntos
Bactérias/isolamento & purificação , Fungos/isolamento & purificação , Kumis/microbiologia , Animais , Bactérias/classificação , China , Fermentação , Fungos/classificação , Cavalos , Kluyveromyces/isolamento & purificação , Lactobacillus , Micobioma , Probióticos , Saccharomyces/isolamento & purificação
14.
FEMS Microbiol Lett ; 364(16)2017 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-28859276

RESUMO

A novel lactose-responsive promoter of the ATP-binding cassette (ABC) transporter gene Lba1680 of Lactobacillus acidophilus strain 05-172 isolated from a traditionally fermented dairy product koumiss was characterized. In L. acidophilus 05-172, expression of Lba1680 was induced by lactose, with lactose-induced transcription of Lba1680 being 6.1-fold higher than that induced by glucose. This is in contrast to L. acidophilus NCFM, a strain isolated from human feces, in which expression of Lba1680 and Lba1679 is induced by glucose. Both gene expression and enzyme activity assays in L. paracasei transformed with a vector containing the inducible Lba1680 promoter (PLba1680) of strain 05-172 and a heme-dependent catalase gene as reporter confirmed that PLba1680 is specifically induced by lactose. Its regulatory expression could not be repressed by glucose, and was independent of cAMP receptor protein. This lactose-responsive promoter might be used in the expression of functional genes in L. paracasei incorporated into a lactose-rich environment, such as dairy products.


Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Regulação Bacteriana da Expressão Gênica , Regulação Enzimológica da Expressão Gênica , Kumis/microbiologia , Lactobacillus acidophilus/enzimologia , Lactose/metabolismo , Regiões Promotoras Genéticas , Proteína Receptora de AMP Cíclico/genética , Proteína Receptora de AMP Cíclico/metabolismo , Vetores Genéticos , Glucose/metabolismo , Lactobacillus acidophilus/genética
15.
J Dairy Sci ; 99(10): 7852-7863, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27522429

RESUMO

Koumiss is considered as a complete dairy product high in nutrients and with medicinal properties. The bacterial communities involved in production of koumiss play a crucial role in the fermentation cycle. To reveal bacterial biodiversity in koumiss and the dynamics of succession in bacterial populations during fermentation, 22 samples were collected from 5 sampling sites and the full length of the 16S ribosomal RNA genes sequenced using single molecule real-time sequencing technology. One hundred forty-eight species were identified from 82 bacterial genera and 8 phyla. These results suggested that the structural difference in the bacterial community could be attributed to geographical location. The most significant difference in bacterial composition occurred in samples from group D compared with other groups. The sampling location of group D was distant from the city and maintained the primitive local nomadic life. The dynamics of succession in bacterial communities showed that Lactobacillus helveticus increased in abundance from 0 to 9h and reached its peak at 9h and then decreased. In contrast, Enterococcus faecalis, Enterococcus durans, and Enterococcus casseliflavus increased gradually throughout the fermentation process, and reached a maximum after 24h.


Assuntos
Kumis , RNA Ribossômico 16S/genética , Animais , Biodiversidade , China , DNA Bacteriano/genética , Fermentação
16.
J Dairy Sci ; 99(9): 7002-7015, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27423943

RESUMO

The growing emergence of antibiotic-resistant bacteria in the food industry needs to be controlled with effective antimicrobials. In this study, bacteriocin MN047 A (BMA) was found to have antibacterial activity against multidrug-resistant bacteria. It was produced by Lactobacillus crustorum MN047, which was first isolated from koumiss, a traditional fermented dairy product from Xinjiang Autonomous Region, China. It was purified by ammonium sulfate precipitation, ion-exchange chromatography, and reversed-phase chromatography. It had a low molecular mass of 1,770.89 Da according to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and the sequence was identified as QLPWQILGIVAGMFQA by liquid chromatography-tandem mass spectrometry analysis and MASCOT searching. It was proteinaceous in nature: the bacteriocin was digested by protease but not by α-amylase or lipase. It showed broad pH toleration (pH 2-11), good thermostability, and good storage stability. It had a broad inhibitory spectrum, including both gram-positive and gram-negative bacteria. Growth curve and time-kill kinetics indicated that it was bactericidal to the indicator strains, and this finding was verified by scanning electron microscope and transmission electron microscope after treatment with BMA. As well, BMA halted the growth of Staphylococcus aureus and Escherichia coli in the G1 and G2/M phases according to cell-cycle analysis by flow cytometry, indicating that BMA had comprehensive inhibitory effects against foodborne pathogens.


Assuntos
Kumis/microbiologia , Lactobacillus/metabolismo , Animais , Bacteriocinas/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Lactobacillus/isolamento & purificação , Peso Molecular , Staphylococcus aureus/efeitos dos fármacos
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