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1.
Int J Mol Sci ; 21(7)2020 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-32276519

RESUMO

Lactic acid bacteria can act as reservoirs of antibiotic resistance genes that can be ultimately transferred to pathogens. The present work reports on the minimum inhibitory concentration (MIC) of 16 antibiotics to 25 LAB isolates of five Lactobacillus and one Bifidobacterium species from the human vagina. Acquired resistances were detected to kanamycin, streptomycin, chloramphenicol, gentamicin, and ampicillin. A PCR analysis of lactobacilli failed to identify genetic determinants involved in any of these resistances. Surprisingly, a tet(W) gene was detected by PCR in two Bifidobacterium bifidum strains, although they proved to be tetracycline-susceptible. In agreement with the PCR results, no acquired genes were identified in the genome of any of the Lactobacillus spp. strains sequenced. A genome analysis of B. bifidum VA07-1AN showed an insertion of two guanines in the middle of tet(W) interrupting the open reading frame. By growing the strain in the presence of tetracycline, stable tetracycline-resistant variants were obtained. An amino acid substitution in the ribosomal protein S12 (K43R) was further identified as the most likely cause of VA07-1AN being streptomycin resistance. The results of this work expand our knowledge of the resistance profiles of vaginal LAB and provide evidence for the genetic basis of some acquired resistances.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana/genética , Lactobacillales/fisiologia , Polimorfismo Genético , Vagina/microbiologia , Bifidobacterium bifidum/efeitos dos fármacos , Bifidobacterium bifidum/genética , Bifidobacterium bifidum/fisiologia , Feminino , Humanos , Lactobacillales/efeitos dos fármacos , Lactobacillales/genética , Lactobacillus/efeitos dos fármacos , Lactobacillus/genética , Lactobacillus/fisiologia , Tetraciclina/farmacologia
2.
Int J Food Microbiol ; 322: 108547, 2020 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-32097827

RESUMO

The present study aimed to characterize lactic acid bacteria involved in the different processing steps of tchapalo, a traditional Ivoirian beverage, for their potential application as starter cultures in food and beverages. Lactic acid bacteria (LAB) were therefore isolated and enumerated at different steps of the process on MRS and BEA agars. Of the 465 isolates, 27 produced bacteriocins that inhibit Lactobacillus delbrueckii F/31 strain. Of those, two also inhibited Listeria innocua ATCC 33090, while two others displayed inhibitory activity against L.innocua ATCC 33090, E. faecalis CIP 105042, E. faecalis ATCC 29212, Streptococcus sp. clinical LNSP, E. faecalis CIP 105042 and E. faecium ATCC 51558. The dominant species involved in tchapalo LAB fermentation, as determined by 16S rRNA gene sequencing, were Lactobacillus fermentum (64%), followed by Pediococcus acidilactici (14%). Two strains representing the two dominant species, L. fermentum S6 and P. acidilactici S7, and two potential bacteriocin producers, Weissella confusa AB3E41 and Enterococcus faecium AT1E22, were selected for further characterization. First, genome analysis showed that these strains do not display potential harmful genes such as pathogenic factors or transmissible antibiotic resistance genes. Furthermore, phylogenetic analyses were performed to assess evidence of eventual links to groups of strains with particular properties. They revealed that (i) L. fermentum S6 and P. acidilactici S7 are closely related to strains that ferment plants, (ii) E. faecium AT1E22 belongs to the environmental clade B of E. faecium, while W. confusa is quite similar to other strains also isolated from plant fermentations. Further genome analysis showed that E. faecium AT1E22 contains the Enterocin P gene probably carried by a megaplasmid, whereas no evidence of a bacteriocin gene was found in W. confusa AB3E41. The metabolic and the first step of the probiotic potentials of the different strains were analyzed. Lactobacillus fermentum S6 and P. acidilactici S7 are good candidates to develop starter cultures, and E. faecium AT1E22 should be further tested to confirm its potential as a probiotic strain in the production of sorghum wort.


Assuntos
Cerveja/microbiologia , Lactobacillales/isolamento & purificação , Sorghum/microbiologia , Bacteriocinas/genética , Bacteriocinas/metabolismo , Fermentação , Genoma Bacteriano/genética , Lactobacillales/classificação , Lactobacillales/genética , Lactobacillales/metabolismo , Listeria/crescimento & desenvolvimento , Filogenia , Probióticos/classificação , Probióticos/metabolismo , RNA Ribossômico 16S/genética
3.
Food Microbiol ; 87: 103385, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31948626

RESUMO

The present work was carried out to evaluate the microbiological and physicochemical composition of salamis produced with the meat of beef, horse, wild boar and pork. Salami productions occurred under controlled laboratory conditions to exclude butchery environmental contaminations, without the addition of nitrate and nitrite. All trials were monitored during the ripening (13 °C and 90% relative humidity) extended until 45 d. The evolution of physicochemical parameters showed that beef and pork salamis were characterized by a higher content of branched chain fatty acids (FA) and rumenic acid than horse and wild boar salamis, whereas the last two productions showed higher values of secondary lipid oxidation. Plate counts showed that lactic acid bacteria (LAB), yeasts and coagulase-negative staphylococci (CNS) populations dominated the microbial community of all productions with Lactobacillus and Staphylococcus as most frequently isolated bacteria. The microbial diversity evaluated by MiSeq Illumina showed the presence of members of Gammaproteobacteria phylum, Moraxellaceae family, Acinetobacter, Pseudomonas, Carnobacterium and Enterococcus in all salamis. This study showed the natural evolution of indigenous fermented meat starter cultures and confirmed a higher suitability of horse and beef meat for nitrate/nitrite free salami production due to their hygienic quality at 30 d.


Assuntos
Alimentos e Bebidas Fermentados/microbiologia , Produtos da Carne/microbiologia , Animais , Bovinos , Fermentação , Alimentos e Bebidas Fermentados/análise , Microbiologia de Alimentos , Cavalos , Lactobacillales/genética , Lactobacillales/crescimento & desenvolvimento , Lactobacillales/isolamento & purificação , Produtos da Carne/análise , Carne Vermelha/microbiologia , Staphylococcus/genética , Staphylococcus/crescimento & desenvolvimento , Staphylococcus/isolamento & purificação , Sus scrofa , Suínos
4.
J Sci Food Agric ; 100(4): 1448-1457, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31756265

RESUMO

BACKGROUND: Baixi sufu (BS) is a traditional Chinese spicy fermented bean curd manufactured with a natural starter. In this study, the bacterial and fungal communities during BS fermentation were determined by culture and by the culture-independent method of high-throughput sequencing (HTS). Correlation analyses were performed to select the microorganisms potentially contributing to this fermentation. RESULTS: During the fermentation of BS, 162 bacterial and 97 fungal strains were isolated and identified, and a total of 268 314 bacterial and 287 844 fungal high-quality sequences were analyzed. In general, lactic acid bacteria (LAB), especially Enterococcus and Lactococcus, were dominant in the early stage of fermentation, and spore-forming bacteria, especially Bacillus spp., became the predominant bacteria by the end of fermentation. Geotrichum, Mortierella, and unclassified Ascomycota, were the major fungal populations, which could not be detected in the final product. Correlation analyses indicated that Enterococcus, Bacillus, Geotrichum, and unclassified Ascomycota correlated significantly and positively with amino nitrogen. However, due to the sporulation characteristics of Bacillus, they may have little effect on BS ripening. The presence of Bifidobacterium spp. in sufu is reported for the first time, but the excessive counts of the Bacillus cereus group (>105 CFU g-1 ) indicate a potential hazard to consumers. CONCLUSION: The profiles obtained from this study will contribute to the development of autochthonous starter cultures to control BS fermentation, and may lead to the development of novel strategies to shorten the fermentation time of sufu products. © 2019 Society of Chemical Industry.


Assuntos
Fabaceae/microbiologia , Fungos/metabolismo , Lactobacillales/metabolismo , Micobioma , Fabaceae/metabolismo , Fermentação , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Sequenciamento de Nucleotídeos em Larga Escala , Lactobacillales/classificação , Lactobacillales/genética , Lactobacillales/isolamento & purificação
5.
J Dairy Sci ; 103(1): 106-116, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31629514

RESUMO

Camel milk has significant economic value and is an important food in the region of Alxa Left Banner of Inner Mongolia. Fifteen fresh camel milk samples were collected from domesticated camels in a pasture of Alxa Left Banner. The physicochemical properties and bacterial diversity of camel milk samples were analyzed. The average values of fat, total protein, nonfat milk solids, acidity, and density were 4.40%, 3.87%, 9.50%, 16.95°T, and 1.02 g/cm3, respectively. The bacterial microbiota of the collected fresh camel milk was investigated using PacBio single-molecule real-time (Pacific Biosciences, Menlo Park, CA) sequencing. The camel milk microbiota was highly diverse and comprised 8,513 operational taxonomic units belonging to 32 phyla, 377 genera, and 652 species. The major phyla included Proteobacteria, Firmicutes, Deinococcus-Thermus, Bacteroidetes, and Actinobacteria. A small number of lactic acid bacteria sequences were detected, representing the species Streptococcus thermophilus, Lactobacillus helveticus, Lactococcus lactis, and Leuconostoc mesenteroides. A total of 72 strains of lactic acid bacteria were isolated and identified from 15 samples, including Lactobacillus paracasei, Enterococcus italicus, Enterococcus durans, Lactococcus lactis ssp. lactis, Weissella confusa, and Enterococcus faecium. These results confirm that fresh camel milk has a high bacterial diversity and is a valuable natural resource for isolation of novel lactic acid bacteria.


Assuntos
Bactérias/classificação , Camelus , Microbiologia de Alimentos , Leite/química , Leite/microbiologia , Animais , China , Lactobacillales/genética , Microbiota , Reação em Cadeia da Polimerase
6.
Lett Appl Microbiol ; 70(1): 48-54, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31642537

RESUMO

This study aims to describe the native microbiota of fermented spelt, taking into consideration both lactic acid bacteria (LAB) and yeasts, for which little data are available. Five samples of commercial spelt flour were subjected to spontaneous fermentation to obtain a type I sourdough. A total of 186 LAB and 174 yeast isolates were selected at different refreshment steps and subjected to further analyses. Within LAB, coccal isolates constituted 78·5% of the total LAB, with the dominance of Pediococcus pentosaceus. Although documented before as a component, this is the first report of a spelt sourdough fermentation dominated by this homofermentative LAB, characterized by a high acidification rate, ability to utilize a wide range of carbon sources and to grow in high osmolarity conditions. Yeast communities resulted in four dominant species, Saccharomyces cerevisiae, Wickerhamomyces anomalus, Pichia fermentans and Clavispora lusitaniae. This study highlights for the first time the biodiversity and dynamics of yeast communities involved in sourdough fermentation of spelt. Compared to commercial baker's yeast, autochthonous W. anomalus, P. fermentans and S. cerevisiae isolates show a good performance, and their use could be an advantage for their acquired adaptation to the environment, providing stability to the fermentation process. SIGNIFICANCE AND IMPACT OF THE STUDY: Nowadays, there is a renewed interest in products based on spelt. This 'ancient grain' is a highly nutritional grain; however, its use is limited to bread-making processes, which are not standardized. The low baking and sensory quality of spelt can be overcome through fermentation processes. However, the autochthonous microbiota of spelt sourdough is poorly known. This study highlights the dynamics of microbial communities involved in sourdough fermentation of spelt and provides the basis for the selection of autochthonous cultures, with the aim of improving the nutritional potential of spelt and its rheology and bread-making properties.


Assuntos
Pão/microbiologia , Lactobacillales/metabolismo , Consórcios Microbianos , Triticum/microbiologia , Leveduras/metabolismo , Biodiversidade , Pão/análise , Fermentação , Farinha/microbiologia , Microbiologia de Alimentos , Lactobacillales/classificação , Lactobacillales/genética , Lactobacillales/isolamento & purificação , Triticum/metabolismo , Leveduras/classificação , Leveduras/genética , Leveduras/isolamento & purificação
7.
J Dairy Sci ; 103(1): 161-165, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31733872

RESUMO

Lactococcus lactis, one of the most important probiotic lactic acid bacteria (LAB), is widely used in the dairy industry as a cell factory for recombinant protein production. Currently, a nisin-controlled inducible expression system is used for this purpose and represents the only commercial expression system in LAB. However, the available genetic modification methods are rather limited for modulating gene expression in L. lactis. Here, we developed a 2-plasmid system for gene transcription repression in L. lactis NZ9000 that uses inducible clustered regularly interspaced short palindromic repeats (CRISPR)-dCas9. An inducible promoter Pnisin was used to drive the expression of dCas9 from Streptococcus pyogenes, whereas a strong constitutive promoter P44 drove single guide RNA expression for single or multiple target genes. dCas9 enabled CRISPR interference-mediated silencing of single or multiple target genes with significant reduction of gene expression, up to 99%. In addition, LLNZ_07335, a putative penicillin acylase, was identified as bile salt hydrolase for bile salt resistance in NZ9000 using this system. To our knowledge, this report is the first for a functional gene for bile salt tolerance in L. lactis. Overall, our work introduces a new gene repression tool for various applications in L. lactis or other LAB.


Assuntos
Lactobacillales/genética , Lactococcus lactis/genética , RNA Guia/genética , Sistemas CRISPR-Cas , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Marcação de Genes , Lactobacillales/enzimologia , Lactococcus lactis/enzimologia , Nisina/metabolismo , Plasmídeos/genética , Regiões Promotoras Genéticas/genética
8.
J Dairy Sci ; 103(2): 1238-1249, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31864732

RESUMO

Cheese is a fermented dairy product that is popular for its unique flavor and nutritional value. Recent studies have shown that microorganisms in cheese play an important role in the fermentation process and determine the quality of the cheese. We collected 12 cheese samples from different regions and studied the composition of their bacterial communities using PacBio small-molecule real-time sequencing (Pacific Biosciences, Menlo Park, CA). Our data revealed 144 bacterial genera (including Lactobacillus, Streptococcus, Lactococcus, and Staphylococcus) and 217 bacterial species (including Lactococcus lactis, Streptococcus thermophilus, Staphylococcus equorum, and Streptococcus uberis). We investigated the flavor quality of the cheese samples using an electronic nose system and we found differences in flavor-quality indices among samples from different regions. We found a clustering tendency based on flavor quality using principal component analysis. We found correlations between lactic acid bacteria and the flavor quality of the cheese samples. Biodegradation and metabolism of xenobiotics, and lipid-metabolism-related pathways, were predicted to contribute to differences in cheese flavor using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). This preliminary study explored the bacterial communities in cheeses collected from different regions and their potential genome functions from the perspective of flavor quality.


Assuntos
Bactérias/isolamento & purificação , Queijo/microbiologia , Variação Genética , Bactérias/classificação , Bactérias/genética , Queijo/análise , DNA Bacteriano/análise , Microbiologia de Alimentos , Lactobacillales/genética , Lactobacillales/isolamento & purificação , Lactobacillus/genética , Lactobacillus/isolamento & purificação , Lactococcus lactis/genética , Lactococcus lactis/isolamento & purificação , Filogenia , Análise de Sequência de DNA , Streptococcus/genética , Streptococcus/isolamento & purificação , Streptococcus thermophilus/genética , Streptococcus thermophilus/isolamento & purificação
9.
World J Microbiol Biotechnol ; 35(10): 156, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31576430

RESUMO

Adhesion ability is a primary criterion for the selection of probiotic microorganisms. Lactic acid bacteria contribute the majority of microorganisms with probiotic properties. They have several important mechanisms for intestinal epithelial cell adhesion. In order to adhere to the intestinal cells, they generally use various structures such as flagella, pili, S layer proteins, lipoteichoic acid, exopolysaccharides and mucus binding proteins. Various in vitro experiments were designed or study models were developed to reveal the mechanisms they utilize for binding to the intestinal cells, yet, the mechanisms for their adhesion are not fully explained. The major disadvantage of conventional models is the lack of layers forming the intestinal mucosa. Besides, these models omit the presence of natural microbiota, digestive conditions and the presence of a food matrix. Because of the disadvantages of existing models, natural tissues or novel applications like 3D organ cultures, which are better able to mimic in vivo conditions, are preferred.


Assuntos
Aderência Bacteriana , Mucosa Intestinal/microbiologia , Lactobacillales/fisiologia , Animais , Células Epiteliais/microbiologia , Humanos , Lactobacillales/genética , Modelos Biológicos
10.
Int J Mol Sci ; 20(16)2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31443334

RESUMO

This study reports the first application of a next generation sequencing (NGS) analysis. The analysis was designed to monitor the effect of the management of microbial resources associated with alcoholic fermentation on spontaneous malolactic consortium. Together with the analysis of 16S rRNA genes from the metagenome, we monitored the principal parameters linked to MLF (e.g., malic and lactic acid concentration, pH). We encompass seven dissimilar concrete practices to manage microorganisms associated with alcoholic fermentation: Un-inoculated must (UM), pied-de-cuve (PdC), Saccharomyces cerevisiae (SC), S. cerevisiae and Torulaspora delbrueckii co-inoculated and sequentially inoculated, as well as S. cerevisiae and Metschnikowia pulcherrima co-inoculated and sequentially inoculated. Surprisingly, each experimental modes led to different taxonomic composition of the bacterial communities of the malolactic consortia, in terms of prokaryotic phyla and genera. Our findings indicated that, uncontrolled AF (UM, PdC) led to heterogeneous consortia associated with MLF (with a relevant presence of the genera Acetobacter and Gluconobacter), when compared with controlled AF (SC) (showing a clear dominance of the genus Oenococcus). Effectively, the SC trial malic acid was completely degraded in about two weeks after the end of AF, while, on the contrary, malic acid decarboxylation remained uncomplete after 7 weeks in the case of UM and PdC. In addition, for the first time, we demonstrated that both (i) the inoculation of different non-Saccharomyces (T. delbrueckii and M. pulcherrima) and, (ii) the inoculation time of the non-Saccharomyces with respect to S. cerevisiae resources (co-inoculated and sequentially inoculated) influence the composition of the connected MLF consortia, modulating MLF performance. Finally, we demonstrated the first findings of delayed and inhibited MLF when M. pulcherrima, and T. delbrueckii were inoculated, respectively. In addition, as a further control test, we also assessed the effect of the inoculation with Oenococcus oeni and Lactobacillus plantarum at the end of alcoholic fermentation, as MLF starter cultures. Our study suggests the potential interest in the application of NGS analysis, to monitor the effect of alcoholic fermentation on the spontaneous malolactic consortium, in relation to wine.


Assuntos
Metagenoma/genética , Vinho/microbiologia , Fermentação/genética , Fermentação/fisiologia , Lactobacillales/genética , Lactobacillales/metabolismo , Lactobacillus plantarum/genética , Lactobacillus plantarum/metabolismo , RNA Ribossômico 16S , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Torulaspora/genética , Torulaspora/metabolismo
11.
Tuberculosis (Edinb) ; 117: 24-30, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31378264

RESUMO

The aim of this study was to determine the reliability of lactic acid bacteria (LAB) as heterologous hosts for the expression of MPB70 and MPB83, two Mycobacterium bovis antigens that possess diagnostics and immunogenic properties, respectively. We therefore generated recombinant cells of Lactococcus lactis and Lactobacillus plantarum that carried hybrid genes encoding MPB70 and MPB83 fused to signal peptides that are specifically recognized by LAB. Only L. lactis was able to secrete MPB70 using the L. lactis signal peptide Usp45, and to produce MPB83 as an immunogenic membrane protein following its expression with the signal peptide of the L. plantarum lipoprotein prsA. Inactivated cells of MPB83-expressing L. lactis cultures enhanced NF-κB activation in macrophages. Our results show that L. lactis is a reliable host for the secretion and functional expression of antigens that are naturally produced by M. bovis, the causative agent of bovine tuberculosis (bTB). This represents the first step on a long process to establishing whether recombinant LAB could serve as a food-grade platform for potential diagnostic tools and/or vaccine interventions for use against bTB, a chronic disease that primarily affects cattle but also humans and a wide range of domestic and wild animals.


Assuntos
Antígenos de Bactérias/metabolismo , Proteínas de Bactérias/metabolismo , Lactobacillales/metabolismo , Proteínas de Membrana/metabolismo , Mycobacterium bovis/imunologia , Antígenos de Bactérias/genética , Proteínas de Bactérias/genética , Células Cultivadas , DNA Bacteriano/biossíntese , Expressão Gênica , Vetores Genéticos/imunologia , Humanos , Lactobacillales/genética , Lactobacillus plantarum/genética , Lactobacillus plantarum/metabolismo , Lactococcus lactis/genética , Lactococcus lactis/metabolismo , Macrófagos/metabolismo , Macrófagos/microbiologia , Proteínas de Membrana/genética , NF-kappa B/metabolismo , Recombinação Genética
12.
Curr Microbiol ; 76(10): 1095-1104, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31270565

RESUMO

Fermented cereals are part of the main traditional diets of many people in Africa, usually obtained from artisanal production. The intensification of their manufacturing, responding to the consumers demand, requires a better control to ensure their sanitary, nutritional, and taste qualities, hence, the need of selecting accurate and safe starter cultures. In the present study, 48 lactic acid bacteria (LAB) strains, previously isolated from Algerian fermented wheat lemzeiet, were analyzed for different technological properties. 14 LAB strains, belonging to Pediococcus pentosaceus, Enterococcus faecium, Lactobacillus curvatus, Lactobacillus brevis, and Leuconostoc mesenteroides species, decreased rapidly the pH of the flour extract broth close to 4 or below. 91% of strains showed extracellular protease activity, but only 12% were amylolytics. 18 LAB strains inhibited or postponed the growth of three fungal targets Rhodotorula mucilaginosa UBOCC-A-216004, Penicillium verrucosum UBOCC-A-109221, and Aspergillus flavus UBOCC-A-106028. The strains belonging to Lactobacillus spp., Leuconostoc fallax, L. mesenteroides, and Weissella paramesenteroides were the most antifungal ones. Multiplex PCR for biogenic amines' production did not reveal any of the genes involved in the production of putrescine, histamine, and tyramine for 17 of the 48 strains. The obtained results provided several candidates for use as starter culture in the future production of lemzeiet.


Assuntos
/microbiologia , Microbiologia de Alimentos , Lactobacillales/isolamento & purificação , Lactobacillales/metabolismo , Triticum/microbiologia , Amilases/metabolismo , Antifúngicos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Aminas Biogênicas/biossíntese , DNA Bacteriano/genética , Fermentação , Concentração de Íons de Hidrogênio , Lactobacillales/enzimologia , Lactobacillales/genética , Peptídeo Hidrolases/metabolismo
13.
World J Microbiol Biotechnol ; 35(7): 100, 2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31222403

RESUMO

The spontaneously fermented curdled milk product from Burkina Faso, lait caillé is prepared by traditional processing from raw unpasteurised milk. The fermentation lasts 1-3 days. This study aims to identify the predominant microbiota involved in lait caillé fermentation from cow milk. A survey on lait caillé end-products from local markets showed pH ranges of 3.5 to 4.2. Counts of total lactic acid bacteria (LAB) were 7.8 ± 0.06 to 10.0 ± 0.03 log CFU/g and yeast counts were 5.3 ± 0.06 to 8.7 ± 0.01 log CFU/g, together with considerate amounts of Enterobacteriaceae < 3.00 to 8.4 ± 0.14 log CFU/g. Sampling throughout the entire fermentation of lait caillé was performed at a traditional house-hold production site. A drop in pH from 6.7 ± 0.01 at 0 h to 4.3 ± 0.08 in the end-product (59 h) was found. Total LAB counts increased to 8.6 ± 0.02 log CFU/g in the end-product, while yeast and Enterobacteriaceae counts reached 6.4 ± 0.11 and 6.7 ± 0.00 log CFU/g, respectively. LAB and yeasts isolated during the fermentation were clustered by (GTG)5 repetitive-PCR fingerprinting followed by 16S and 26S rRNA gene sequencing, respectively. Microbial successions were observed with Leuconostoc mesenteroides being the predominant LAB followed by Pediococcus pentosaceus and Weissella paramesenteroides at the onset, while Lactococcus lactis and Enterococcus spp. where the predominant LAB after 7 h of fermentation. During the first 18 h Candida parapsilosis was the dominant yeast species, while from 35 h to the end-product, Saccharomyces cerevisiae predominated. The microbial safety risk pointed out in this study, showed the need for implementation of good manufacturing practices including pasteurisation and use of well-defined starter cultures.


Assuntos
Produtos Fermentados do Leite/microbiologia , Microbiota/genética , Burkina Faso , Contagem de Colônia Microbiana , Enterobacteriaceae/genética , Enterobacteriaceae/isolamento & purificação , Enterococcus/genética , Enterococcus/isolamento & purificação , Fermentação , Manipulação de Alimentos , Microbiologia de Alimentos , Concentração de Íons de Hidrogênio , Lactobacillales/genética , Lactobacillales/isolamento & purificação , Lactococcus lactis/genética , Lactococcus lactis/isolamento & purificação , RNA Ribossômico/genética , RNA Ribossômico/isolamento & purificação , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/isolamento & purificação , Análise de Sequência de RNA , Leveduras/genética , Leveduras/isolamento & purificação
14.
Mol Biotechnol ; 61(8): 562-578, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31161300

RESUMO

Lactic acid bacteria (LAB) are functional starter cultures in food and dairy industry and are also regarded as power houses for bioprocess and fermentation technology. Due to extensive applications in food and medical applications, intensive research and developmental activities are going on throughout the world to understand the genomic and metabolic aspects during the past few decades. These LAB strains have significant role in production of value added chemicals and fuels from lignocellulosic biomass and other by-product streams establishing a circular bioeconomy. In this context, we discuss the physiology and genetics of crude glycerol dissimilation in lactic acid bacteria, the value added chemicals produced from biodiesel-derived crude glycerol. The overview of metabolic engineering strategies to improve the cellular traits and future perspectives in constructing cellulolytic/hemicellulolytic LAB strains to establish a renewable and sustainable cost-effective biorefinery is discussed.


Assuntos
Biocombustíveis/microbiologia , Genoma Bacteriano/genética , Glicerol/metabolismo , Lactobacillales , Engenharia Metabólica , Lactobacillales/genética , Lactobacillales/metabolismo
15.
Appl Microbiol Biotechnol ; 103(15): 5947-5955, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31175431

RESUMO

Over the past two decades, lactic acid bacteria (LAB) have been intensively studied as potential bacterial carriers for therapeutic materials, such as vaccine antigens, to the mucosal tissues. LAB have several attractive advantages as carriers of mucosal vaccines, and the effectiveness of LAB vaccines has been demonstrated in numerous studies. Research on LAB vaccines to date has focused on whether antigen-specific immunity, particularly antibody responses, can be induced. However, with recent developments in immunology, microbiology, and vaccinology, more detailed analyses of the underlying mechanisms, especially, of the induction of cell-mediated immunity and memory cells, have been required for vaccine development and licensure. In this mini-review, we will discuss the issues, including (i) immune responses other than antibody production, (ii) persistence of LAB vaccine immunity, (iii) comparative evaluation of LAB vaccines with any existing or reference vaccines, (iv) strategies for increasing the effectiveness of LAB vaccines, and (iv) effects of microbiota on the efficacy of LAB vaccines. Although these issues have been rarely studied or discussed to date in relation to LAB vaccine research, further understanding of them is critical for the practical application of LAB vaccine systems.


Assuntos
Portadores de Fármacos , Imunidade nas Mucosas , Lactobacillales/genética , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologia , Administração através da Mucosa , Pesquisa Biomédica/tendências , Tecnologia Farmacêutica/tendências , Vacinas Sintéticas/administração & dosagem
16.
Lett Appl Microbiol ; 69(3): 204-211, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31250457

RESUMO

Despite of the beneficial relevance of several lactic acid bacteria (LAB) in the food industry, micro-organisms belonging to this group can determine spoilage in food products and carry a number of virulence and antibiotic resistance-related genes. This study aimed on the characterization of beneficial and safety aspects of five bacteriocinogenic LAB strains (Lactobacillus curvatus 12-named L. curvatus UFV-NPAC1), L. curvatus 36, Weissela viridescens 23, W. viridescens 31 and Lactococcus garvieae 36) isolated from an artisanal Brazilian calabresa, a traditional meat sausage. Regarding their beneficial aspects, all tested isolates were positive for mub, while EF226-cbp, EF1249-fbp and EF2380-maz were detected in at least one tested strain; none of the isolates presented map, EFTu or prgB. However, evaluated strains presented a variable pattern of virulence-related genes, but none of the strains presented gelE, cylA, efsA, cpd, int-Tn or sprE. Moreover, other virulence-related genes evaluated in this study were detected at different frequencies. L. curvatus 12 was generated positive results for ace, ccf, int, ermC, tetL, aac(6')-Ie-aph(2″)-Ia, aph(2″)-Ib, aph(2″)-Ic, bcrB, vanB and vanC2; L. curvatus 36: hyl, asa1, esp, int, ermC, tetK, aph(3')-IIIa, aph(2'')-Ic and vanC2; L. garvieae 32: asa1, ant(4')-Ia, aph(2'')-Ib, catA, vanA and vanC1; W. viridescens 23: esp, cob, ermB, aph(3')-IIIa, aph(2'')-Ic, vanA, vanB and vanC2; W. viridescens 31: hyl, esp, ermC, aph(3')-IIIa, aph(2'')-Ib, aph(2'')-Ic, catA, vanA and vanB. Despite presenting some beneficial aspects, the presence of virulence and antibiotic resistance genes jeopardize their utilization as starter or biopreservatives cultures in food products. Considering the inhibitory potential of these strains, an alternative would be the use of their bacteriocins as semi-purified or pure technological preparation. SIGNIFICANCE AND IMPACT OF THE STUDY: The food industry has a particular interest in using bacteriocinogenic lactic acid bacteria (LAB) as starter, probiotics and/or biopreservatives in different food products. Characterization of additional beneficial features is important to identify new, multifunctional potential probiotic strains. However, these strains can only be applied in food products only after being properly characterized according their potential negative aspects, such as virulence and antibiotic resistance genes. A wide characterization of beneficial and safety aspects of bacteriocinogenic LAB is determinant to guide the proper utilization of these strains, or their purified bacteriocins, by the food industry.


Assuntos
Antibacterianos/farmacologia , Bacteriocinas/biossíntese , Lactobacillales/genética , Fatores de Virulência/genética , Brasil , Resistência Microbiana a Medicamentos/genética , Enterococcus/isolamento & purificação , Microbiologia de Alimentos , Lactobacillales/isolamento & purificação , Lactobacillus/efeitos dos fármacos , Lactococcus/isolamento & purificação , Produtos da Carne/microbiologia , Virulência
17.
Pol J Microbiol ; 68(2): 203-209, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31250590

RESUMO

The composition of vagina lactic acid bacteria (LAB) differs within the different ethnic group. This study is aimed at determining the prevalence of LAB with their antimicrobial properties in Nigerian women's vagina during different stages of the menstrual cycle. Microorganisms were isolated from vaginal swabs of ten Nigerian women during different stages of the menstrual cycle and identified by partial sequencing of the 16S rRNA gene. The antimicrobial properties of the LAB were tested against the multidrug-resistant uropathogens. The prevalence of LAB was higher during ovulation period while during menstruation period, it declined. Twenty-five LAB isolates were identified as three species, namely: Lactobacillus plantarum (15), Lactobacillus fermentum (9), Lactobacillus brevis (1) and one acetic acid bacteria - Acetobacter pasteurianus. The LAB had antimicrobial activities against the three uropathogens with zones of inhibition from 8 to 22 mm. The presence of LAB inhibits the growth of Staphylococcus sp. GF01 also in the co-culture. High LAB counts were found during ovulation period with L. plantarum as a dominant species while during menstruation, there was a decrease in the LAB counts. The isolated LAB has antimicrobial properties against the urogenital pathogens tested thus exhibiting their potential protective role against uropathogens.The composition of vagina lactic acid bacteria (LAB) differs within the different ethnic group. This study is aimed at determining the prevalence of LAB with their antimicrobial properties in Nigerian women's vagina during different stages of the menstrual cycle. Microorganisms were isolated from vaginal swabs of ten Nigerian women during different stages of the menstrual cycle and identified by partial sequencing of the 16S rRNA gene. The antimicrobial properties of the LAB were tested against the multidrug-resistant uropathogens. The prevalence of LAB was higher during ovulation period while during menstruation period, it declined. Twenty-five LAB isolates were identified as three species, namely: Lactobacillus plantarum (15), Lactobacillus fermentum (9), Lactobacillus brevis (1) and one acetic acid bacteria ­ Acetobacter pasteurianus. The LAB had antimicrobial activities against the three uropathogens with zones of inhibition from 8 to 22 mm. The presence of LAB inhibits the growth of Staphylococcus sp. GF01 also in the co-culture. High LAB counts were found during ovulation period with L. plantarum as a dominant species while during menstruation, there was a decrease in the LAB counts. The isolated LAB has antimicrobial properties against the urogenital pathogens tested thus exhibiting their potential protective role against uropathogens.


Assuntos
Antibiose , Lactobacillales/isolamento & purificação , Lactobacillales/fisiologia , Ciclo Menstrual , Vagina/microbiologia , Acetobacter/classificação , Acetobacter/genética , Acetobacter/isolamento & purificação , Acetobacter/fisiologia , Adulto , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Feminino , Humanos , Lactobacillales/classificação , Lactobacillales/genética , Nigéria , Filogenia , Prevalência , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Staphylococcus/crescimento & desenvolvimento , Adulto Jovem
18.
Appl Microbiol Biotechnol ; 103(13): 5079-5093, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31069487

RESUMO

Glycerol is one of the most important substrates involved in phospholipid biosynthesis, along with dihydroxyacetone phosphate (DHAP) as an intermediate of glycolysis. Organisms produce glycerol 3-phosphate (G3P) from endogenous DHAP and/or exogenous glycerol to synthesize glycerophospholipids from G3P. On the other hand, organisms can utilize glycerol as a carbon source to generate adenosine triphosphate (ATP). Glycerol metabolism in microorganisms has been investigated for > 50 years. The main research targets have been four bacteria that can utilize glycerol efficiently: Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, and Enterococcus faecalis. E. coli, E. aerogenes, and K. pneumoniae are gram-negative bacteria in the Enterobacteriales order of the class γ-Proteobacteria. In contrast, E. faecalis is a gram-positive bacterium in the Lactobacillales order of the class Bacilli, which are well-known lactic acid bacteria (LAB). Therefore, the glycerol metabolism of E. faecalis is characterized by the properties of both gram-positive bacteria and LAB, which substantially differ from the other three bacteria. As glycerophospholipids are essential for LAB, genes encoding the enzyme for glycerol metabolism (including G3P synthesis) are broadly detected from various LAB. However, these LAB's classification and trend remained unclear until now, along with each LAB's ability to utilize glycerol. Hence, the present review summarizes LAB's glycerol metabolic pathway and regulation mechanism based on the distribution of the genes involved in those and discusses the peculiarities of glycerol metabolism in E. faecalis.


Assuntos
Regulação Bacteriana da Expressão Gênica , Glicerol/metabolismo , Lactobacillales/genética , Lactobacillales/metabolismo , Redes e Vias Metabólicas , Metabolismo dos Carboidratos , Enterococcus faecalis/genética , Enterococcus faecalis/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/metabolismo
19.
BMC Microbiol ; 19(1): 88, 2019 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-31060586

RESUMO

BACKGROUND: Lactococcus lactis strain Plasma (LC-Plasma) possesses strong stimulatory activity for plasmacytoid dendritic cells (pDCs) via the TLR9-Myd88 pathway. To reveal the effective lactic acid bacteria (LAB) genome structure for pDCs stimulatory activity, we performed in vitro screening, using randomly selected 200 bp DNA fragments from the LC-Plasma genome. RESULTS: We found that the CpG motif copy number in the fragments was positively and significantly correlated with pDCs stimulatory activity (R = 0.491, p < 0.01). However, the determination coefficient (R2) was 0.24, which means other factors affecte activity. We found that the G + C contents of the fragment showed a significant negative correlation with activity (R = - 0.474, p < 0.01). The correlation between pDCs stimulatory activity and the copy number of CpG motifs was greatly increased when DNA fragments were stratified by G + C contents. We also performed bioinformatics analysis and a screening of LAB strains with high pDCs stimulatory activity. Species with a high copy number of CpG motifs in the low-G + C region of their genomes had higher probability of inducing high-pDCs stimulatory activity. L. lactis subsp. lactis, Leuconostoc mesenteroides, and Pediococcus pentosaceus were three typical examples of LAB that had high pDCs stimulatory activity. CONCLUSIONS: Our data suggested that the G + C content of DNA is one of the critical factors for pDCs stimulatory activity by DNA fragments. Furthermore, we found that the copy number in the low-G + C regions strongly affected the pDCs stimulatory activity of whole cells of LAB strains. These results should be useful for the design of new DNA fragments containing CpG motifs. This study also demonstrated an in silico screening method for identifying bacterial species that are able to activate pDCs.


Assuntos
DNA Bacteriano/imunologia , Células Dendríticas/imunologia , Genoma Bacteriano , Lactobacillales/genética , Animais , Composição de Bases , Células Cultivadas , Ilhas de CpG , Feminino , Genômica , Camundongos , Camundongos da Linhagem 129 , Oligodesoxirribonucleotídeos
20.
Int J Food Microbiol ; 301: 61-72, 2019 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-31100643

RESUMO

Phyllosphere microorganisms are common contaminants of fruit or vegetable containing foods. The aim of this study was to identify and characterize lactic acid bacteria isolated from fruits and vegetables from Reunion Island, regarding possible application in food. Among 77 isolates, a large diversity of species was observed, with isolates belonging to Lactobacillus plantarum (3 isolates), other species of Lactobacillus (3), Lactococcus lactis (13), Leuconostoc pseudomesenteroides (25), Leuconostoc lactis (1), Leuconostoc mesenteroides (7), Leuconostoc citreum (14), Weissella cibaria (4), Weissella confusa (4), other species of Weissella (2) and Fructobacillus tropaeoli (1). Several of these species, although belonging to lactic acid bacteria, are poorly characterized, because of their low occurrence in dairy products. Lactobacillus, Lactococcus, Leuconostoc and Weissella isolates were classified by (GTG)5 fingerprinting in 3, 6, 21 and 10 genetic groups, respectively, suggesting a large intra-species diversity. Several Weissella and Lactobacillus isolates were particularly tolerant to acid and osmotic stress, whereas Lc. pseudomesenteroides 60 was highly tolerant to oxidative stress. Isolates of Weissella 30, 64 and 58, Leuconostoc 60 and 12b, Lactobacillus 75 and Fructobacillus 77 present relevant characteristics for their use as starters or as preservative cultures for fruits and vegetables.


Assuntos
Microbiologia de Alimentos , Frutas/microbiologia , Lactobacillales/genética , Verduras/microbiologia , Fermentação , Lactobacillales/isolamento & purificação , Lactobacillales/fisiologia , RNA Ribossômico 16S/genética , Clima Tropical
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