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1.
An Acad Bras Cienc ; 93(suppl 3): e20190478, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34468488

RESUMO

In this study, it was determinated the essential oil of cultivated apple mint, Mentha suaveolens Ehrh. composition and in vitro antibacterial activity of against 11 fish pathogen bacteria including Gram-positive (Staphylococcus warneri, Staphylococcus sp., Lactococcus garvieae, Vagococus salmoninarum) and Gram-negative (Aeromonas hydrophila, Aeromonas sobria Aeromonas cavieae, Vibrio anguillarum, Pseudomonas aeroginosa, Yersinia ruckeri, Edwardsiella tarda) by using agar diffusion assay. The main component of M. suaveolence oil was obtained as piperitenone oxide. The essential oil exhibited strong inhibitory activity such as inhibition zone sizes: 30-50mm at 250-1000 µL mL-1 concentrations against V. anguillarum; 16-20mm at 31.25-125 µL mL-1 concentrations against P. aeroginosa; 15-18mm at 500-1000 µL mL-1 concentrations against A. sobria. However, it was found to be moderately effective against E. tarda (8-15 mm), Y. ruckeri (9-12mm), S. warneri (9-10mm), V. salmoninarum (9mm) and Staphylococcus sp. (8-9mm). The essential oil showed weak inhibitory activity against A. cavieae (5-8), A. hydrophila (6-7mm), L. garvieae (5-7mm). Thus, effect of essential oil of M. suaveolens on immune response and disease resistance against Vibrio anguillarum, A. sobria and P. aeroginosa should be investigated in vivo in cultured fish species in future studies.


Assuntos
Aeromonas , Doenças dos Peixes , Mentha , Óleos Voláteis , Animais , Antibacterianos/farmacologia , Doenças dos Peixes/tratamento farmacológico , Lactococcus , Óleos Voláteis/farmacologia , Staphylococcus , Vibrio
2.
Food Res Int ; 148: 110600, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34507745

RESUMO

The microbiota of cheese plays a critical role in determining its organoleptic and other physicochemical properties. Thus, assessing the composition of the cheese microbiota community would help promote the growth of desirable taxa and ultimately to optimize flavor, quality and safety. Here we measured microbial diversity, microbiota composition, short-chain fatty acids, and free amino acids in two traditional cheese-making strategies, Rushan and Rubing, processed in parallel from Lijiang, Eryuan, and Dengchuan of Yunnan province, China. We found distinct microbiota composition, and microbial diversity and richness in both Rushan and Rubing across all three regions, which were proportional to the scale of the cities where the cheeses were sampled. Furthermore, we found positive associations of Streptococcus and Acinetobacter with butyric acid, Phe and Tyr, which were negatively correlated with Lactococcus. For the first time, we provide evidence that environmental microbial contamination in cheese can be correlated with the manufacturing procedures and geographical regions. This should be paid more attention in upcoming cheese microbiota studies.


Assuntos
Queijo , Microbiota , Queijo/análise , China , Lactococcus , Streptococcus
3.
Int J Food Microbiol ; 357: 109382, 2021 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-34509932

RESUMO

Dairy farm management practices can modify milk microbiota and therefore modulate non-starter lactic acid bacteria (NSLAB) found in cheese. These NSLAB can cause organoleptic defects. This study aimed to investigate the impact of two potential NSLAB in Cheddar cheesemaking: Lactiplantibacillus plantarum RKG 2-212 a strain isolated both in corn silage and raw milk, and Lactobacillus delbrueckii RKG R10, a strain isolated after pasteurisation of milk from a farm using grass and legume silage, and corn silage. The whole genome of these two lactobacilli was first sequenced. Then, the thermoresistance was evaluated after treatment at 60 °C for 5 min and compared to reference strains. Both lactobacilli were highly thermoresistant compared to other three lactic acid bacteria which are Lactococcus lactis subsp. cremoris ATCC 19257 and SK11, and L. plantarum ATCC 14917 (P < 0.0001). They lost less than 1 log cfu/mL (Δlog) and their genome contained a great number of copy number of genes coding for heat shock protein. During a Pearce test activity simulating Cheddar cheesemaking, the two lactobacilli did not show interaction with the starter Lcc. lactis subsp. cremoris SK11, and their population remained stable. During a ripening simulation, L. delbrueckii RKG R10 had a slight loss in viability in cheese slurry samples incubated at 30 °C for 12 d. However, L. plantarum RKG 2-212 had considerable growth, from 6.51 to 8.3 log cfu/g. This growth was associated with the acidification of the slurries (P < 0.0001). The presence of the lactobacilli modified the profile of volatile compounds evaluated by gas chromatography-mass spectrometry, accounting for 10.7% of the variation. The strain L. plantarum RKG 2-212 produced volatile compounds in greater quantity that could be associated with organoleptic defects such as acetic acid and 2-methylbutyraldehyde. Therefore, silage can be a vector of thermoresistant lactic acid bacteria for milk which can lead to flavor defects in cheese.


Assuntos
Queijo , Lactobacillales , Lactococcus lactis , Animais , Lactobacillales/genética , Lactococcus , Lactococcus lactis/genética , Leite
4.
J Med Microbiol ; 70(8)2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34397349

RESUMO

Introduction. Lactococcus petauri LZys1 (L. petauri LZys1) is a type of lactic acid bacteria (LAB), which was initially isolated from healthy human gut.Hypothesis/Gap Statement. It was previously anticipated that L. petauri LZys1 has potential characteristics of probiotic properties. The genetic structure and the regulation functions of L. petauri LZys1 need to be better revealed.Aim. The aim of this study was to detect the probiotic properties L. petauri LZys1 and to reveal the genome information related to its genetic adaptation and probiotic profiles.Methodology. Multiple in vitro experiments were carried out to evaluate its lactic acid-producing ability, resistance to pathogenic bacterial strains, auto-aggregation and co-aggregation ability, and so on. Additionally, complete genome sequencing, gene annotation, and probiotic associated gene analysis were performed.Results. The complete genome of L. petauri LZys1 comprised of 1 985 765 bp, with a DNA G+C content of 38.07 %, containing 50 tRNA, seven rRNA, and four sRNA. A total of 1931 genes were classified into six functional categories by Kyoto Encyclopaedia of Genes and Genomes (KEGG) database. The neighbour-joining phylogeny tree based on the whole genome of L. petauri LZys1 and other probiotics demonstrated that L. petauri LZys1 has a significant similarity to Lactococcus garvieae. The functional genes were detected to expound the molecular mechanism and biochemical processes of its potential probiotic properties, such as atpB gene.Conclusion. All the results described in this study, together with relevant information previously reported, made L. prtauri LZys1 a very interesting potential strain to be considered as a prominent candidate for probiotic use.


Assuntos
Trato Gastrointestinal/microbiologia , Genoma Bacteriano , Lactococcus , Probióticos , Animais , Bactérias/crescimento & desenvolvimento , Bactérias/patogenicidade , Sequência de Bases , Fezes/microbiologia , Genes Bacterianos , Humanos , Lactococcus/citologia , Lactococcus/genética , Lactococcus/isolamento & purificação , Lactococcus/fisiologia , Masculino , Anotação de Sequência Molecular , Mariposas/microbiologia , Filogenia , Polissacarídeos Bacterianos/biossíntese , Polissacarídeos Bacterianos/genética , Sequenciamento Completo do Genoma , Adulto Jovem
5.
Artigo em Inglês | MEDLINE | ID: mdl-34427555

RESUMO

Currently, Lactococcus garvieae contains two subspecies: L. garvieae subsp. bovis and L. garvieae subsp. garvieae. In a study by Varsha and Nampoothiri, high pheS (99.7 %) and rpoA (99.6 %) sequence similarities indicated that L. garvieae subsp. bovis and Lactococcus formosensis probably have a close taxonomic relationship; low pheS (92.2 %) and rpoA (97.8 %) sequence similarities and relatively low DNA-DNA hybridization value (75.8 %) indicated that L. garvieae subsp. bovis and L. garvieae subsp. garvieae probably represent two different species. In the present study, the taxonomic relationships between L. garvieae subsp. bovis, L. garvieae subsp. garvieae and L. formosensis were re-examined based on sequence analyses of 16S rRNA, pheS, recA, rpoA and rpoB genes, average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH) values, average amino acid identity (AAI), fatty acid methyl ester analysis and phenotypic characterization. L. garvieae subsp. bovis LMG 30663T exhibited 97.3 % ANI, 78.3 % dDDH and 96.4 % AAI values to L. formosensis NBRC 109475T, higher than the threshold for species demarcation (95-96, 70 and 95-96 %, respectively), indicating that L. garvieae subsp. bovis LMG 30663T and L. formosensis NBRC 109475T belong to the same species. L. garvieae subsp. bovis LMG 30663T had 91.2 % ANI, 43.3 % dDDH and 92.9-93.0% AAI values with the type strain of L. garvieae subsp. garvieae, indicating that they represent two different species. Because L. formosensis has been proposed and validated before L. garvieae subsp. bovis, L. garvieae subsp. bovis is transferred to L. formosensis as L. formosensis subsp. bovis comb. nov. The type strain of L. formosensis subsp. bovis is BSN307T (=DSM 100577T=MCC 2824T=KCTC 21083T=LMG 30663T). The type strain of L. formosensis subsp. formosensis is 516T (=NBRC 109475T=BCRC 80576T).


Assuntos
Lactococcus/classificação , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Genes Bacterianos , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
6.
Int J Mol Sci ; 22(16)2021 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-34445321

RESUMO

Listeria monocytogenes is an important food-borne pathogen and a serious concern to food industries. Bacteriocins are antimicrobial peptides produced naturally by a wide range of bacteria mostly belonging to the group of lactic acid bacteria (LAB), which also comprises many strains used as starter cultures or probiotic supplements. Consequently, multifunctional strains that produce bacteriocins are an attractive approach to combine a green-label approach for food preservation with an important probiotic trait. Here, a collection of bacterial isolates from raw cow's milk was typed by 16S rRNA gene sequencing and MALDI-Biotyping and supernatants were screened for the production of antimicrobial compounds. Screening was performed with live Listeria monocytogenes biosensors using a growth-dependent assay and pHluorin, a pH-dependent protein reporting membrane damage. Purification by cation exchange chromatography and further investigation of the active compounds in supernatants of two isolates belonging to the species Pediococcus acidilactici and Lactococcus garvieae suggest that their antimicrobial activity is related to heat-stable proteins/peptides that presumably belong to the class IIa bacteriocins. In conclusion, we present a pipeline of methods for high-throughput screening of strain libraries for potential starter cultures and probiotics producing antimicrobial compounds and their identification and analysis.


Assuntos
Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Descoberta de Drogas/métodos , Listeria monocytogenes/efeitos dos fármacos , Probióticos , Animais , Antibacterianos/biossíntese , Bacteriocinas/biossíntese , Lactococcus/isolamento & purificação , Lactococcus/metabolismo , Microbiota , Leite/microbiologia , Pediococcus acidilactici/isolamento & purificação , Pediococcus acidilactici/metabolismo
7.
Ann Palliat Med ; 10(7): 7933-7941, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34353080

RESUMO

BACKGROUND: Acne vulgaris is a chronic inflammatory skin disease of the pilosebaceous units which can affect the individual's physiological and psychological health. Abnormal growth of lipophilic anaerobic bacteria such as Propionibacterium acnes is reported to be a major factor in the development of acne. However, the relationship between skin microorganisms and acne has not been fully elucidated. Our study aimed to explore the microbial differences between patients with acne and healthy controls (HCs). METHODS: The study involved 16 participants diagnosed with acne vulgaris and 5 HCs. We collected skin microbe samples from the cheeks, brow, forehead, neck, chin, or chest of the participants with sterile cotton swabs depending on the location of the acne lesions. Cutaneous microbe samples from the participants were tested by 16s sequencing. RESULTS: Patients with acne showed increased diversity of skin microbiota in their samples. OTU535601 (Lachnospiraceae), OTU4460604 (Clostridiales), OTU3217705 (Moraxellaceae), OTU1066814 (Prevotella), and OTU455671 (Lactococcus garvieae) were the top 5 most abundant species found in patients with acne but were not present in HCs. OTU423327 (Achromobacter), OTU4423360 (Stenotrophomonas), OTU993127 (Porphyromonas), OTU677680 (Prevotella), and OTU269901 (Pseudomonas) were the top 5 most abundant species in HCs but were not found in patients with acne. CONCLUSIONS: The present study has analyzed and compared the diversity and abundance of microorganisms and the characteristics of the main pathogenic bacteria in patients with acne and HCs. Our findings indicate the importance of maintaining the skin's commensal microflora balance with the development of acne vulgaris.


Assuntos
Acne Vulgar , Microbiota , Humanos , Lactococcus , Propionibacterium acnes
8.
Molecules ; 26(16)2021 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-34443691

RESUMO

BACKGROUND: Milk is considered an important source of bioactive peptides, which can be produced by endogenous or starter bacteria, such as lactic acid bacteria, that are considered effective and safe producers of food-grade bioactive peptides. Among the various types of milk, donkey milk has been gaining more and more attention for its nutraceutical properties. METHODS: Lactobacillus rhamnosus 17D10 and Lactococcus lactis subsp. cremoris 40FEL3 were selected for their ability to produce peptides from donkey milk. The endogenous peptides and those obtained after bacterial fermentation were assayed for their antioxidant, antibacterial, and antiviral activities. The peptide mixtures were characterized by means of LC-MS/MS and then analyzed in silico using the Milk Bioactive Peptide DataBase. RESULTS: The peptides produced by the two selected bacteria enhanced the antioxidant activity and reduced E. coli growth. Only the peptides produced by L. rhamnosus 17D10 were able to reduce S. aureus growth. All the peptide mixtures were able to inhibit the replication of HSV-1 by more than 50%. Seventeen peptides were found to have 60% sequence similarity with already known bioactive peptides. CONCLUSIONS: A lactic acid bacterium fermentation process is able to enhance the value of donkey milk through bioactivities that are important for human health.


Assuntos
Antibacterianos/farmacologia , Antivirais/farmacologia , Fermentação , Lactobacillus rhamnosus/fisiologia , Lactococcus/fisiologia , Leite/microbiologia , Sequência de Aminoácidos , Animais , Antioxidantes/farmacologia , Quelantes/farmacologia , Equidae , Proteínas do Leite/análise , Peptídeos/química , Peptídeos/farmacologia
9.
Nutrients ; 13(8)2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-34444827

RESUMO

Cutaneous wound healing comprises a complex systemic network. Probiotics, naturally extracted substances, medicine, and chemical compounds have been used for wound healing, but the application of postbiotics as therapeutic agents has yet to be explored. Our study shows potential beneficial effects of heat-killed Lactococcus chungangensis CAU 1447 on type 1 diabetic mice. The postbiotic strain significantly decreased the skin wound size. The activity of myeloperoxidase secreted from neutrophils also decreased. The molecular mechanism of wound healing was adjusted by important mediators, growth factors, chemokines, and cytokines. These elements regulated the anti-inflammatory activity and accelerated wound healing. To determine the role of the postbiotic in wound repair, we showed a similar taxonomic pattern as compared to the diabetic mice using skin microbiome analysis. These findings demonstrated that heat-killed Lactococcus chungangensis CAU 1447 had beneficial effects on wound healing and can be utilized as postbiotic therapeutic agents.


Assuntos
Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 1 , Lactococcus/química , Probióticos/uso terapêutico , Pele/efeitos dos fármacos , Cicatrização , Animais , Quimiocinas/metabolismo , Citocinas/metabolismo , Temperatura Alta , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Lactococcus/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Peroxidase/análise , Pele/patologia , Estreptozocina/efeitos adversos
10.
J Agric Food Chem ; 69(27): 7581-7592, 2021 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-34197112

RESUMO

There is growing evidence that prevention of metabolic syndrome (MS) by dietary fibers is intricately linked to gut microbiota. In the present work, the mice were fed a high-fat diet (HFD) and orally treated with yeast ß-glucan to further examine the effects of ß-glucan on MS and gut microbiota and the potential relationship between gut microbiota and its activity. After intervention for 10 weeks, it was found that the treatment of yeast ß-glucan could significantly improve the HFD-induced MS. Furthermore, pro-inflammatory cytokines in plasma including IL-6 and IL-1ß were decreased. Yeast ß-glucan could regulate the diversity and composition of HFD-induced gut microbiota. Moreover, the relative abundances of Lactobacillus and Lactococcus, having significant positive correlation with metabolic changes, were decreased by ß-glucan, which might play a critical role in attenuation of MS. Our findings suggest that yeast ß-glucan shows promising application as a prebiotic for preventing MS and regulating gut microbiota.


Assuntos
Microbioma Gastrointestinal , Síndrome Metabólica , beta-Glucanas , Animais , Proliferação de Células , Dieta Hiperlipídica/efeitos adversos , Lactobacillus , Lactococcus , Camundongos , Camundongos Endogâmicos C57BL , Saccharomyces cerevisiae/genética
11.
J Dairy Sci ; 104(10): 10609-10627, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34253372

RESUMO

Accurately profiling and characterizing factors shaping raw milk microbiota would provide practical information for detecting microbial contamination and unusual changes in milk. The current work was an observational study aiming to profile the microbiota of raw milk collected across wide geographic regions in China in different seasons and to investigate the contribution of geographical, seasonal, and environmental factors in shaping the raw milk microbiota. A total of 355 raw cow milk samples from healthy Holsteins and 41 environmental samples (farm soil and surface of milking room floor) were collected from 5 dairy farms in 5 Chinese provinces (namely, Daqing in Heilongjiang province, Jiaozuo in Henan province, Qingyuan in Guangdong province, Suqian in Jiangsu province, and Yinchuan in Ningxia Hui Autonomous Region) in January, May, and September 2018. The microbial communities in raw milk and farm environmental samples were determined using the PacBio small-molecule real-time circular consensus sequencing, which generated high-fidelity microbiota profiles based on full-length 16S rRNA genes; such technology was advantageous in producing accurate species-level information. Our results showed that both seasonality and sampling region were significant factors influencing the milk microbiota; however, the raw milk microbiota was highly diverse according to seasonality, and sampling region was the less determining factor. The wide variation in raw milk microbial communities between samples made it difficult to define a representative species-level core milk microbiota. Nevertheless, 3 most universal milk-associated species were identified: Lactococcus lactis, Enhydrobacter aerosaccus, and Acinetobacter lwoffii, which were consistently detected in 99%, 95%, and 94% of all analyzed milk samples, respectively (n = 355). The top taxa accounting for the overall seasonal microbiota variation were Bacillus (Bacillus cereus, Bacillus flexus, Bacillus safensis), Lactococcus (Lactococcus lactis, Lactococcus piscium, Lactococcus raffinolactis), Lactobacillus (Lactobacillus helveticus, Lactobacillus delbrueckii), Lactiplantibacillus plantarum, Streptococcus agalactiae, Enhydrobacter aerosaccus, Pseudomonas fragi, and Psychrobacter cibarius. Unlike the milk microbiota, the environmental microbiota did not exhibit obvious pattern of seasonal or geographic variation. However, this study was limited by the relatively low number and types of environmental samples, making it statistically not meaningful to perform further correlation analysis between the milk and environmental microbiota. Nevertheless, this study generated novel information on raw milk microbiota across wide geographic regions of China and found that seasonality was more significant in shaping the raw milk microbiota compared with geographic origin.


Assuntos
Microbiota , Leite , Acinetobacter , Animais , Bacillus , Bovinos , Feminino , Microbiologia de Alimentos , Lactococcus , Psychrobacter , RNA Ribossômico 16S/genética , Rhodospirillales
12.
J Mol Biol ; 433(11): 166887, 2021 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-33972022

RESUMO

RiPPMiner-Genome is a unique bioinformatics resource for identifying Biosynthetic Gene Clusters (BGC) for RiPPs (Ribosomally Synthesized and Post-translationally Modified Peptides) and automated prediction of crosslinked chemical structures of RiPPs starting from genomic sequences. It is a major update of the RiPPMiner webserver, which used only peptide sequence of RiPP precursors as input for predicting RiPP class and crosslinked chemical structures. Other major improvements are, machine learning (ML) based identification of correct RiPP precursor peptide from among multiple small ORFs (Open Reading Frames) in a BGC, prediction of the cleavage site and cross-links in thiopeptides and identification of non-crosslinked modified residues in lanthipeptides. It has been benchmarked on a dataset of 204 experimentally characterized RiPP BGCs. RiPPMiner-Genome also facilitates visualization of the RiPP BGCs and depiction of the chemical structure of crosslinked RiPP. It also has an interface for searching characterized RiPPs, similar to the predicted core peptide sequence or crosslinked chemical structure.


Assuntos
Reagentes para Ligações Cruzadas/química , Mineração de Dados , Genoma Bacteriano , Internet , Peptídeos/metabolismo , Processamento de Proteína Pós-Traducional , Ribossomos/metabolismo , Software , Automação , Sequência de Bases , Lactococcus/genética , Aprendizado de Máquina , Reprodutibilidade dos Testes
13.
Res Vet Sci ; 137: 170-173, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33991889

RESUMO

Lactococcus (L.) garvieae is a zoonotic fish pathogen that can also cause bacteraemia and endocarditis in humans and has been isolated from healthy or diseased domestic animals. Nevertheless L. garvieae is more an opportunistic, than a primary pathogen since most affected humans have predisposing conditions and comorbidities. L. garvieae is also present in other animal species, most frequently cattle, but also sheep, goats, water buffaloes, and pigs, and much more rarely dogs, cats, horses, camel, turtle, snake and crocodile. The purpose of this study was to genomically (i) confirm the identification by MALDI-TOF MS® of a L. garvieae from the nasal discharge of a dog with chronic respiratory disorders and (ii) compare this canine isolate with human and animal L. garvieae isolates. According to the BLAST analysis after Whole Genome Sequencing, this canine isolate was more than 99% identical to 3 L. garvieae and belonged to a new Multi-Locus Sequence Type (ST45). MLST and whole genomes-based phylogenetic analysis were performed on the canine isolate and the 40 genomes available in Genbank. The canine L. garvieae was most closely related to an Australian camel and an Indian fish L. garvieae and more distantly to human L. garvieae. Twenty-five of the 29 putative virulence-associated genes searched for were detected, but not the 16 capsule-encoding genes. The heterogeneity of the L. garvieae species is reflected by the diversity of the MLSTypes and virulotypes identified and by the phylogenetic analysis.


Assuntos
Doenças do Cão/microbiologia , Microbiologia Ambiental , Lactococcus/genética , Infecções Respiratórias/veterinária , Animais , Cães , Genômica , Humanos , Lactococcus/classificação , Lactococcus/isolamento & purificação , Masculino , Tipagem de Sequências Multilocus/veterinária , Filogenia , Infecções Respiratórias/microbiologia
14.
Int J Food Microbiol ; 348: 109208, 2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-33940536

RESUMO

Microbiological spoilage of meat is considered as a process which involves mainly bacterial metabolism leading to degradation of meat sensory qualities. Studying spoilage requires the collection of different types of experimental data encompassing microbiological, physicochemical and sensorial measurements. Within this framework, the objective herein was to carry out a multiblock path modelling workflow to decipher causality relationships between different types of spoilage-related responses: composition of microbiota, volatilome and off-odour profiles. Analyses were performed with the Path-ComDim approach on a large-scale dataset collected on fresh turkey sausages. This approach enabled to quantify the importance of causality relationships determined a priori between each type of responses as well as to identify important responses involved in spoilage, then to validate causality assumptions. Results were very promising: the data integration confirmed and quantified the causality between data blocks, exhibiting the dynamical nature of spoilage, mainly characterized by the evolution of off-odour profiles caused by the production of volatile organic compounds such as ethanol or ethyl acetate. This production was possibly associated with several bacterial species like Lactococcus piscium, Leuconostoc gelidum, Psychrobacter sp. or Latilactobacillus fuchuensis. Likewise, the production of acetoin and diacetyl in meat spoilage was highlighted. The Path-ComDim approach illustrated here with meat spoilage can be applied to other large-scale and heterogeneous datasets associated with pathway scenarios and represents a promising key tool for deciphering causality in complex biological phenomena.


Assuntos
Bactérias/metabolismo , Produtos da Carne/microbiologia , Carne/microbiologia , Compostos Orgânicos Voláteis/análise , Animais , Bactérias/classificação , Microbiologia de Alimentos , Embalagem de Alimentos , Lactococcus/metabolismo , Leuconostoc/metabolismo , Microbiota , Odorantes/análise , Psychrobacter/metabolismo , Perus/microbiologia
15.
Int J Food Microbiol ; 349: 109230, 2021 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-34023621

RESUMO

A mechanistic, spatio-temporal model to predict early stage semi-solid food ripening, exemplary for semi-solid casein matrices, was created using software based on the finite element method (FEM). The model was refined and validated by experimental data obtained during 8 wk of ripening of a casein matrix that was inoculated by one single central injection of starter culture. The resulting spatio-temporal distributions of lactococci strains, lactose, lactic acid/lactate and pH allowed us to optimize a number of parameters of the predictive model. Using the optimized model, the agreement between simulation and experiment was found to be satisfactory, with the pH matching best. The predictive model unveiled that effective diffusion of substrate and metabolites were crucial for an eventual homogeneous distribution of the measured substances. Hence, while using the optimized parameters from the single injection model, an injection technology for starter culture to inoculate and ferment casein matrices homogeneously was developed by means of solving another optimization problem with respect to injection positions. The casein matrix inoculated by the proposed injection pattern (21 injections, distance = 19 mm) showed sufficient homogeneity (bacterial activity and pH distribution) after the early stages of ripening, demonstrating the potential of application of the injection technology for fermentation of casein-based foods e.g. cheese.


Assuntos
Caseínas/análise , Manipulação de Alimentos/métodos , Modelos Teóricos , Caseínas/metabolismo , Queijo/análise , Queijo/microbiologia , Fermentação , Microbiologia de Alimentos , Concentração de Íons de Hidrogênio , Ácido Láctico/metabolismo , Lactococcus/metabolismo , Lactose/metabolismo
16.
Int J Mol Sci ; 22(7)2021 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-33801752

RESUMO

Bovine mastitis is a significant economic burden for dairy enterprises, responsible for premature culling, prophylactic and therapeutic antibiotic use, reduced milk production and the withholding (and thus wastage) of milk. There is a desire to identify novel antimicrobials that are expressly directed to veterinary applications, do not require a lengthy milk withholding period and that will not have a negative impact on the growth of lactic acid bacteria involved in downstream dairy fermentations. Nisin is the prototypical lantibiotic, a family of highly modified antimicrobial peptides that exhibit potent antimicrobial activity against many Gram-positive microbes, including human and animal pathogens including species of Staphylococcus and Streptococcus. Although not yet utilized in the area of human medicine, nisin is currently applied as the active agent in products designed to prevent bovine mastitis. Over the last decade, we have harnessed bioengineering strategies to boost the specific activity and target spectrum of nisin against several problematic microorganisms. Here, we screen a large bank of engineered nisin derivatives to identify novel derivatives that exhibit improved specific activity against a selection of staphylococci, including mastitis-associated strains, but have unchanged or reduced activity against dairy lactococci. Three such peptides were identified; nisin A M17Q, nisin A T2L and nisin A HTK.


Assuntos
Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Lactococcus/efeitos dos fármacos , Mastite Bovina/microbiologia , Nisina/química , Staphylococcus/efeitos dos fármacos , Animais , Bioengenharia/métodos , Bovinos , Feminino , Testes de Sensibilidade Microbiana , Leite/microbiologia , Peptídeos/química , Engenharia de Proteínas/métodos
17.
Microbiol Res ; 248: 126751, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33839507

RESUMO

In this study, the seed endosphere of a bacterial wilt tolerant chilli cv. Firingi Jolokia was explored in order to find effective agents for bacterial wilt disease biocontrol. A total of 32 endophytic bacteria were isolated from freshly collected seeds and six isolates were selected based on R. solanacearum inhibition assay. These isolates were identified as Bacillus subtilis (KJ-2), Bacillus velezensis (KJ-4), Leuconostoc mesenteroides (KP-1), Lactococcus lactis (LB-3), Bacillus amyloliquefaciens (WK-2), and Bacillus subtilis (WK-3) by 16S rRNA gene sequencing. In the in planta R. solanacearum inhibition assay carried out by seedling root bacterization method, Bacillus subtilis (KJ-2) exhibited highest biocontrol efficacy of 86.6 % on 7th day post R. solanacearum inoculation and a minimum biocontrol efficacy of 52.9 % was noted for Leuconostoc mesenteroides (KP-1). GC-HRMS analysis detected several known antimicrobial compounds in the extract of the culture supernatant of Bacillus subtilis (KJ-2); which may contribute to inhibition of R. solanacearum. In the growth promotion assay conducted using these isolates, only two of them namely Bacillus subtilis (KJ-2) and Bacillus amyloliquefaciens (WK-2) showed growth promotion in true leafed tomato plants. All the selected seed endophytic isolates were able to control bacterial wilt of tomato at the seedling stage and Bacillus subtilis (KJ-2) was found to be most effective in controlling the disease. The results of the present study highlighted that seed endosphere of bacterial wilt tolerant cultivar is a rich source of R. solanacearum antagonizing bacterial isolates.


Assuntos
Antibiose , Bacillus/fisiologia , Capsicum/microbiologia , Proteção de Cultivos/métodos , Endófitos/fisiologia , Lactococcus/fisiologia , Doenças das Plantas/prevenção & controle , Bacillus/classificação , Bacillus/genética , Bacillus/isolamento & purificação , Endófitos/classificação , Endófitos/genética , Endófitos/isolamento & purificação , Lactococcus/classificação , Lactococcus/genética , Lactococcus/isolamento & purificação , Lycopersicon esculentum/crescimento & desenvolvimento , Lycopersicon esculentum/microbiologia , Doenças das Plantas/microbiologia , Ralstonia solanacearum/fisiologia , Plântula/crescimento & desenvolvimento , Plântula/microbiologia , Sementes/microbiologia
18.
Food Res Int ; 140: 109994, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33648228

RESUMO

Bacillus sp. was found in the Sichuan paocai, but their possible effects on Sichuan paocai fermentation are still elusive. In this study, the effect of Bacillus megaterium L222 isolated from high-quality homemade Sichuan paocai on the flavor characteristics and bacterial diversity was investigated. Overall, 7 organic acids, 16 free amino acids, and 48 volatile substances were detected in the B. megaterium L222-inoculated paocai (BMP) and spontaneously fermented paocai (SP) within 7 days. The metabolites produced in BMP were significantly different from that in SP, and 13 main flavor-related metabolites were the discriminant markers. The contents of free amino acids in BMP were much higher than that in SP. Compared to the SP group, the BMP group could better maintain the high level of alcohols, which improved the synthesis of esters, and controlled the increase of the content of sulfides. The representative bacteria in BMP were Weissella, Lactococcus, Bacillus, Leuconostoc, and the inoculation of B. megaterium L222 could significantly increase the amount of Weissella and inhibit the growth of opportunistic pathogen and other bacteria during the fermentation process of paocai. This study presents an important basis for the development of B. megaterium L222 as a starter for paocai fermentation.


Assuntos
Bacillus megaterium , Weissella , Fermentação , Lactococcus , Leuconostoc
19.
J Dairy Sci ; 104(5): 5998-6012, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33685690

RESUMO

The objective was to describe and compare antimicrobial resistance patters of esculin-hydrolyzing streptococci and streptococcal-like organisms (Streptococcus uberis, Enterococcus faecium, Enterococcus faecalis, Lactococcus garvieae, Lactococcus lactis) from routine diagnostic samples of the udder health laboratory of the Bavarian Animal Health Services between 2015 and 2019. All routine diagnostic samples of the udder health laboratory of the Bavarian Animal Health Services, that were tested with a standard microbroth dilution, were eligible to be included in this retrospective case series. A California Mastitis Test result was available for all samples. Most Strep. uberis and L. lactis were susceptible to all antibiotics tested. Enterococcus faecium had consistently the highest minimum inhibitory concentration required to inhibit the growth of 90% of tested isolates. The resistance patterns of Lactococcus garvieae were positioned between enterococci and L. lactis. The minimum inhibitory concentration for various antibiotics and pathogens tended to decrease over the 5-yr period. Regardless of the pathogen, isolates of clinical cases were less likely to express in vitro resistance than isolates of healthy or subclinical cases. Streptococcus uberis or L. lactis showed hardly any in vitro resistance to tested antibiotic groups. Penicillin should remain the first-choice antimicrobial for the therapy of Strep. uberis and Lactococcus spp. However, a success of any antimicrobial treatment of enterococcal infections seems questionable.


Assuntos
Doenças dos Bovinos , Mastite Bovina , Infecções Estreptocócicas , Animais , Antibacterianos/farmacologia , Bovinos , Farmacorresistência Bacteriana , Enterococcus , Feminino , Alemanha , Lactococcus , Leite , Estudos Retrospectivos , Infecções Estreptocócicas/veterinária , Streptococcus
20.
J Dairy Sci ; 104(5): 6061-6079, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33685704

RESUMO

The objective of this prospective cohort study was to explore associations between intramammary infection (IMI) in late-lactation cows and postcalving udder health and productivity. Cows (n = 2,763) from 74 US dairy herds were recruited as part of a previously published cross-sectional study of bedding management and IMI in late-lactation cows. Each herd was visited twice for sampling. At each visit, aseptic quarter milk samples were collected from 20 cows approaching dry-off (>180 d pregnant), which were cultured using standard bacteriological methods and MALDI-TOF for identification of isolates. Quarter-level culture results were used to establish cow-level IMI status at enrollment. Cows were followed from enrollment until 120 d in milk (DIM) in the subsequent lactation. Herd records were used to establish whether subjects experienced clinical mastitis or removal from the herd, and DHIA test-day data were used to record subclinical mastitis events (somatic cell count >200,000 cells/mL) and milk yield (kg/d) during the follow-up period. Cox regression and generalized estimating equations were used to evaluate the associations between IMI and the outcome of interest. The presence of late-lactation IMI caused by major pathogens was positively associated with postcalving clinical mastitis [hazard ratio = 1.5, 95% confidence interval (CI): 1.2, 2.0] and subclinical mastitis (risk ratio = 1.5, 95% CI: 1.3, 1.9). Species within the non-aureus Staphylococcus (NAS) group varied in their associations with postcalving udder health, with some species being associated with increases in clinical and subclinical mastitis in the subsequent lactation. Late-lactation IMI caused by Streptococcus and Streptococcus (Strep)-like organisms, other than Aerococcus spp. (i.e., Enterococcus, Lactococcus, and Streptococcus spp.) were associated with increases in postcalving clinical and subclinical mastitis. Test-day milk yield from 1 to 120 DIM was lower (-0.9 kg, 95% CI: -1.6, -0.3) in late-lactation cows with any IMI compared with cows without IMI. No associations were detected between IMI in late lactation and risk for postcalving removal from the herd within the first 120 DIM. Effect estimates reported in this study may be less than the underlying quarter-level effect size for IMI at dry-off and postcalving clinical and subclinical mastitis, because of the use of late-lactation IMI as a proxy for IMI at dry-off and the use of cow-level exposure and outcome measurements. Furthermore, the large number of models run in this study (n = 94) increases the chance of identifying chance associations. Therefore, confirmatory studies should be conducted. We conclude that IMI in late lactation may increase risk of clinical and subclinical mastitis in the subsequent lactation. The relationship between IMI and postcalving health and productivity is likely to vary among pathogens, with Staphylococcus aureus, Streptococcus spp., Enterococcus spp., and Lactococcus spp. being the most important pathogens identified in the current study.


Assuntos
Aerococcus , Doenças dos Bovinos , Mastite Bovina , Animais , Bovinos , Contagem de Células/veterinária , Estudos Transversais , Enterococcus , Feminino , Lactação , Lactococcus , Glândulas Mamárias Animais , Leite , Gravidez , Estudos Prospectivos , Staphylococcus , Streptococcus
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