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1.
Front Cell Infect Microbiol ; 12: 887921, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35677656

RESUMO

Lactococcus garvieae is an important pathogen of fish, associated with high rates of mortality and infection recurrence in summer or stressful conditions. Chronic infection and disease recurrence have also been reported to be associated with biofilms. However, the impact of biofilm and planktonic bacterial infection on fish immune responses remains unclear. In this study, de novo sequencing was used to compare differences of the spleen transcriptome in planktonic- and biofilm-infected mullets. Among the 181,024 unigenes obtained, 3,392 unigenes were associated with immune response genes. Comparative analysis of the gene expression between infection with the L. garvieae planktonic type and biofilm type identified a total of 3,120 and 3,489 differentially expressed genes in response to planktonic and biofilm infection, respectively, of which 1,366 and 1,458 genes were upregulated, and 1,754 and 1,458 genes were downregulated, respectively. Gene ontology enrichment analysis of immune genes identified genes involved in the complement system, toll-like receptor signaling, and antigen processing, which were further verified by qPCR. Additionally, genes encoding TLR2, IL-1ß, TNF-α, C7, and MHC class II peptides were downregulated in response to biofilm infection. Importantly, the results show that biofilm infection induces a different immune pathway response compared with planktonic bacterial infection and, furthermore, illustrates that the prevention of biofilm formation may be a necessary and new strategy for controlling bacterial infection in aquaculture.


Assuntos
Infecções Bacterianas , Doenças dos Peixes , Smegmamorpha , Animais , Biofilmes , Doenças dos Peixes/microbiologia , Imunidade Inata , Lactococcus , Plâncton/genética , Smegmamorpha/genética , Transcriptoma
2.
Biochem Biophys Res Commun ; 612: 176-180, 2022 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-35550504

RESUMO

Age-related muscle atrophy is associated with decreased protein anabolic capacity. Dietary intervention is an important strategy for the treatment of age-related muscle atrophy. This study examined the effect of Lactococcus cremoris subsp. cremoris FC-fermented milk on muscle mass and protein anabolic signaling in middle-aged mice. Male C57BL/6J mice (18-month-old) were divided into the control and Lactococcus cremoris subsp. cremoris FC-fermented milk supplementation groups. Mice were administered unfermented or fermented milk (300 µL/day) by gavage every alternate day for 8 weeks; thereafter, muscle weight, protein metabolic signaling factors, and inflammatory factors were investigated. Soleus muscle weight was higher in the fermented milk group than in the control group. Expression of insulin growth factor-1, a typical anabolic factor, and phosphorylation levels of anabolic signaling factors (mTOR and p70S6K) were higher after fermented milk supplementation. Levels of tumor necrosis factor-α, an inhibitor of protein anabolism, were lower in the fermented milk group. These data suggest that the daily intake of Lactococcus cremoris subsp. cremoris FC-fermented milk increased skeletal muscle mass as well as protein synthesis in the middle-aged mice, which may be mediated by reduction in the levels of inflammatory factors. Therefore, accelerated protein synthesis, induced by the consumption of fermented milk, has a potential role in counteracting muscle atrophy.


Assuntos
Lactococcus lactis , Animais , Lactococcus , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Leite/metabolismo , Músculo Esquelético , Atrofia Muscular/metabolismo
3.
Int J Mol Sci ; 23(9)2022 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-35563074

RESUMO

Lactococcus garvieae causes infectious diseases in animals and is considered an emerging zoonotic pathogen involved in human clinical conditions. In silico analysis of plasmid pLG50 of L. garvieae Lg-Granada, an isolate from a patient with endocarditis, revealed the presence of two gene clusters (orf46-47 and orf48-49), each one encoding a novel putative bacteriocin, i.e., garvicin AG1 (GarAG1; orf46) and garvicin AG2 (GarAG2; orf48), and their corresponding immunity proteins (orf47 and orf49). The chemically synthesised bacteriocins GarAG1 and GarAG2 presented inhibitory activity against pathogenic L. garvieae strains, with AG2 also being active against Listeria monocytogenes, Listeria ivanovii and Enterococcus faecalis. Genetic organisation, amino acid sequences and antimicrobial activities of GarAG1 and GarAG2 indicate that they belong to linear non-pediocin-like one-peptide class IId bacteriocins. Gram-positive bacteria that were sensitive to GarAG2 were also able to ferment mannose, suggesting that this bacteriocin could use the mannose phosphotransferase transport system (Man-PTS) involved in mannose uptake as a receptor in sensitive strains. Intriguingly, GarAG1 and GarAG2 were highly active against their own host, L. garvieae Lg-Granada, which could be envisaged as a new strategy to combat pathogens via their own weapons.


Assuntos
Bacteriocinas , Animais , Bacteriocinas/metabolismo , Bactérias Gram-Positivas/metabolismo , Humanos , Lactococcus/metabolismo , Manose/metabolismo
4.
Emerg Microbes Infect ; 11(1): 1325-1334, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35475418

RESUMO

Owing to an increasing number of infections in adults, Lactococcus (L.) garvieae has gained recognition as an emerging human pathogen, causing bacteraemia and septicaemia. In September 2020, four paediatric onco-hematologic patients received a platelet concentrate from the same adult donor at Bambino Gesù Children's Hospital IRCCS, Rome. Three of four patients experienced L. garvieae sepsis one day after transfusion. The L. garvieae pediatric isolates and the donor's platelet concentrates were retrospectively collected for whole-genome sequencing and shot-gun metagenomics, respectively (Illumina HiSeq). By de novo assembly of the L. garvieae genomes, we found that all three pediatric isolates shared a 99.9% identity and were characterized by 440 common SNPs. Plasmid pUC11C (conferring virulence properties) and the temperate prophage Plg-Tb25 were detected in all three strains. Core SNP genome-based maximum likelihood and Bayesian trees confirmed their phylogenetic common origin and revealed their relationship with L. garvieae strains affecting cows and humans (bootstrap values >100 and posterior probabilities = 1.00). Bacterial reads obtained by the donor's platelet concentrate have been profiled with MetaPhlAn2 (v.2.7.5); among these, 29.9% belonged to Firmicutes, and 5.16% to Streptococcaceae (>97% identity with L. garvieae), confirming the presence of L. garvieae in the platelet concentrate transfusion. These data showed three episodes of sepsis for the first time due to a transfusion-associated transmission of L. garvieae in three pediatric hospitalized hematology patients. This highlights the importance to implement the screening of platelet components with new human-defined pathogens for ensuring the safety of blood supply, and more broadly, for the surveillance of emerging pathogens.


Assuntos
Lactococcus , Sepse , Teorema de Bayes , Criança , Farmacorresistência Bacteriana , Humanos , Lactococcus/classificação , Lactococcus/genética , Filogenia , Estudos Retrospectivos , Sepse/microbiologia
5.
J Dairy Sci ; 105(5): 3896-3910, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35282916

RESUMO

Paucilactobacillus wasatchensis can use gluconate (GLCN) as well as galactose as an energy source and because sodium GLCN can be added during salting of Cheddar cheese to reduce calcium lactate crystal formation, our primary objective was to determine if the presence of GLCN in cheese is another risk factor for unwanted gas production leading to slits in cheese. A secondary objective was to calculate the amount of CO2 produced during storage and to relate this to the amount of gas-forming substrate that was utilized. Ribose was added to promote growth of Pa. wasatchensis WDC04 (P.waWDC04) to high numbers during storage. Cheddar cheese was made with lactococcal starter culture with addition of P.waWDC04 on 3 separate occasions. After milling, the curd was divided into six 10-kg portions. To the curd was added (A) salt, or salt plus (B) 0.5% galactose + 0.5% ribose (similar to previous studies), (C) 1% sodium GLCN, (D) 1% sodium GLCN + 0.5% ribose, (E) 2% sodium GLCN, (F) 2% sodium GLCN + 0.5% ribose. A vat of cheese without added P.waWDC04 was made using the same milk and a block of cheese used as an additional control. Cheeses were cut into 900-g pieces, vacuum packaged and stored at 12°C for 16 wk. Each month the bags were examined for gas production and cheese sampled and tested for lactose, galactose and GLCN content, and microbial numbers. In the control cheese, P.waWDC04 remained undetected (i.e., <104 cfu/g), whereas in cheeses A, C, and E it increased to 107 cfu/g, and when ribose was included with salting (cheeses B, D, and F) increased to 108 cfu/g. The amount of gas (measured as headspace height or calculated as mmoles of CO2) during 16 wk storage was increased by adding P.waWDC04 into the milk, and by adding galactose or GLCN to the curd. Galactose levels in cheese B were depleted by 12 wk while no other cheeses had residual galactose. Except for cheese D, the other cheeses with GLCN added (C, E and F) showed little decline in GLCN levels until wk 12, even though gas was being produced starting at wk 4. Based on calculations of CO2 in headspace plus CO2 dissolved in cheese, galactose and GLCN added to cheese curd only accounted for about half of total gas production. It is proposed that CO2 was also produced by decarboxylation of amino acids. Although P.waWDC04 does not have all the genes for complete conversion and decarboxylation of the amino acids in cheese, this can be achieved in conjunction with starter culture lactococcal. Adding GLCN to curd can now be considered another confirmed risk factor for unwanted gas production during storage of Cheddar cheese that can lead to slits and cracks in cheese. Putative risk factors now include having a community of bacteria in cheese leading to decarboxylation of amino acids and release of CO2 as well autolysis of the starter culture that would provide a supply of ribose that can promote growth of Pa. wasatchensis.


Assuntos
Queijo , Aminoácidos , Animais , Dióxido de Carbono , Queijo/análise , Manipulação de Alimentos , Galactose/metabolismo , Gluconatos , Lactobacillus , Lactococcus/metabolismo , Ribose , Sódio
6.
Int J Mol Sci ; 23(5)2022 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-35269976

RESUMO

Bacteriocins are emerging as a viable alternative to antibiotics due to their ability to inhibit growth or kill antibiotic resistant pathogens. Herein, we evaluated the ability of the bacteriocin Garvicin KS (GarKS) produced by Lactococcus garvieae KS1546 isolated from cow milk to inhibit the growth of fish and foodborne bacterial pathogens. We found that GarKS inhibited the growth of five fish L. garvieae strains isolated from infected trout and eels. Among fish pathogens, GarKS inhibited the growth of Streptococcus agalactiae serotypes Ia and Ib, and Aeromonas hydrophila but did not inhibit the growth of Edwardsiella tarda. In addition, it inhibited the growth of A. salmonicida strain 6421 but not A. salmonicida strain 6422 and Yersinia ruckeri. There was no inhibition of three foodborne bacterial species, namely Salmonella enterica, Klebsiella pneumoniae, and Escherichia coli. In vitro cytotoxicity tests using different GarKS concentrations showed that the highest concentration of 33 µg/mL exhibited low cytotoxicity, while concentrations ≤3.3 µg/mL had no cytotoxicity on CHSE-214 and RTG-2 cells. In vivo tests showed that zebrafish larvae treated with 33 µg/mL and 3.3 µg/mL GarKS prior to challenge had 53% and 48% survival, respectively, while concentrations ≤0.33 µg/mL were nonprotective. Altogether, these data show that GarKS has a broad inhibitory spectrum against Gram positive and negative bacteria and that it has potential applications as a therapeutic agent for a wide range of bacterial pathogens. Thus, future studies should include clinical trials to test the efficacy of GarKS against various bacterial pathogens in farmed fish.


Assuntos
Bacteriocinas , Doenças dos Peixes , Yersiniose , Animais , Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Bovinos , Feminino , Doenças dos Peixes/tratamento farmacológico , Doenças dos Peixes/microbiologia , Doenças dos Peixes/prevenção & controle , Lactococcus , Larva , Peixe-Zebra
7.
World J Microbiol Biotechnol ; 38(4): 69, 2022 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-35257236

RESUMO

Human gut-originated lactic acid bacteria were cultivated, and high γ-aminobutyric acid (GABA)-producing Lactococcus garvieae MJF010 was identified. To date, despite the importance of GABA, no studies have investigated GABA-producing Lactococcus species, except for Lc. lactis. A recombinant glutamate decarboxylase of the strain MJF010 (rLgGad) was successfully expressed in Escherichia coli BL21(DE3) with a size of 53.9 kDa. rLgGad could produce GABA, which was verified using the silylation-derivative fragment ions of GABA. The purified rLgGad showed the highest GABA-producing activity at 35 °C and pH 5. rLgGad showed a melting temperature of 43.84 °C. At 30 °C, more than 80% of the activity was maintained even after 7 h; however, it rapidly decreased at 50 °C. The kinetic parameters, Km, Vmax, and kcat, of rLgGad were 2.94 mM, 0.023 mM/min, and 12.3 min- 1, respectively. The metal reagents of CaCl2, MgCl2, and ZnCl2 significantly had positive effects on rLgGad activity. However, most coenzymes including pyridoxal 5'-phosphate showed no significant effects on enzyme activity. In conclusion, this is the first report of Gad from Lc. garvieae species and provides important enzymatic information related to GABA biosynthesis in the Lactococcus genus.


Assuntos
Glutamato Descarboxilase , Lactococcus , Escherichia coli/genética , Escherichia coli/metabolismo , Glutamato Descarboxilase/química , Glutamato Descarboxilase/genética , Humanos , Lactococcus/genética , Lactococcus/metabolismo , Ácido gama-Aminobutírico
8.
J Fish Dis ; 45(6): 771-781, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35235703

RESUMO

Lactococcus garvieae is the etiological agent of Lactococcosis, an evolving disease affecting many fish species and causing significant economic losses worldwide. Assessing pathogen relatedness and bacterial population structure is critical for determining the epidemiology of L. garvieae infections and in establishing effective pathogen management methods. The previously published morphological and genetic studies point to a clonal population structure, as seen in other fish bacteria. In the present study, the pulsed-field gel electrophoresis (PFGE) method was utilized to define a population of 41 Taiwanese isolates from outbreaks with comparisons to four well-characterized non-Taiwanese isolates previously published. Two restriction enzymes (ApaI and SmaI) were utilized individually for PFGE analysis (cut-off value = 90.0%), revealing genetic heterogeneity across L. garvieae isolates, with ApaI and SmaI yielding 12 and seven distinct PFGE band patterns, respectively. The phylogenic analysis using internal transcribed spacer region clustered all L. garvieae isolates in the same clad. Furthermore, the electron microscopic results confirmed the absence of capsular gene cluster (CGC) in previously characterized Taiwanese vaccine strain (S3) from grey mullet. Overall, our findings emphasize the importance of analysing the morphological and genetic diversity in L. garvieae being correlated for proper taxonomic classification in vaccine strain selection and epidemiological studies.


Assuntos
Doenças dos Peixes , Animais , Eletroforese em Gel de Campo Pulsado/veterinária , Doenças dos Peixes/microbiologia , Peixes , Genótipo , Lactococcus/genética , Microscopia Eletrônica
9.
J Fish Dis ; 45(6): 847-859, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35306674

RESUMO

Piscine lactococcosis is an emergent bacterial disease that is associated with high economic losses in many farmed and wild aquatic species worldwide. Early and accurate detection of the causative agent of piscine lactococcosis is essential for management of the disease in fish farms. In this study, a TaqMan quantitative polymerase chain reaction (qPCR) targeting the 16S-23S rRNA internal transcribed spacer region was developed and validated. Validation of the qPCR was performed with DNA of previously typed L. petauri and L. garvieae recovered from different aquatic hosts from distinct geographical locations, closely related bacterial species and common pathogens in trout aquaculture. Further diagnostic sensitivity and specificity was investigated by screening of fish, water and faecal samples. The developed qPCR assay showed high specificity, sensitivity and accuracy in detection of L. petauri and L. garvieae with lack of signals from non-target pathogens, and in screening of rainbow trout (Oncorhynchus mykiss) posterior kidney and environmental samples. The detection limit of the qPCR was four amplicon copies. Moreover, the sensitivity of the qPCR assay was not affected by presence of non-target DNA from either fish or environmental samples. The robustness, specificity and sensitivity of the developed qPCR will facilitate fast and accurate diagnosis of piscine lactococcosis to establish appropriate control measures in fish farms and aquaria.


Assuntos
Doenças dos Peixes , Oncorhynchus mykiss , Animais , DNA , Doenças dos Peixes/microbiologia , Lactococcus/genética , Oncorhynchus mykiss/microbiologia , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/genética
10.
Behav Brain Res ; 426: 113847, 2022 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-35306095

RESUMO

Clinical evidence suggests that neuroinflammation, activation of the immune system, and the composition of the intestinal microbiota are involved in the pathology of depression. This study evaluated the effectiveness of a probiotic intervention using Lactococcus lactis subsp. cremoris LL95 in ameliorating mood disorders in a lipopolysaccharide (LPS)-induced depression-like mouse model. C57BL/6 mice were randomly divided into four groups and treated with 5 mg/kg LPS via intraperitoneal injection to induce depression-like symptoms, followed by oral administration of LL95 for one week (1â€¯× 109 CFU/mouse). The animals were then subjected to a series of behavioral assessments, including open field, sucrose preference, and forced swimming tests. In addition, we evaluated the levels of reactive oxygen species, tumor necrosis factor-α, and interleukin-1ß in the hippocampal tissues of these animals, and also determined their fecal lactic acid bacteria (LAB) content. LL95 intervention improved LPS-induced depression-like behaviors in mice, including decreased sucrose preference and increased immobility time in the forced swim test. LL95 treatment reversed the LPS-induced increase in hippocampal levels of reactive oxygen species and tumor necrosis factor-α, and of interleukin-1ß to a lesser extent. Furthermore, LL95 intervention increased the fecal LAB content in these animals, suggesting changes in the gut microbiota. These findings suggest that LL95 exerts antidepressant-like effects in LPS-induced depression, which may be attributed to modulation of the oxidative status and pro-inflammatory cytokine expression in the hippocampus and alteration in the LAB content of the gut microbiota.


Assuntos
Lactococcus lactis , Lipopolissacarídeos , Animais , Depressão/induzido quimicamente , Depressão/tratamento farmacológico , Depressão/metabolismo , Lactococcus , Lipopolissacarídeos/farmacologia , Camundongos , Camundongos Endogâmicos C57BL
11.
Int J Biol Macromol ; 206: 203-212, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35183603

RESUMO

A novel bifunctional ß-lactamase/esterase (LgLacI), which is capable of hydrolyzing ß-lactam-containing antibiotics including ampicillin, oxacillin, and cefotaxime as well as synthesizing biodiesels, was cloned from Lactococcus garvieae. Unlike most bacterial esterases/lipases that have G-x-S-x-G motif, LgLacI, which contains S-x-x-K catalytic motif, has sequence similarities to bacterial family VIII esterase as well as ß-lactamases. The catalytic properties of LgLacI were explored using a wide range of biochemical methods including spectroscopy, assays, structural modeling, mutagenesis, and chromatography. We confirmed the bifunctional property of LgLacI hydrolyzing both esters and ß-lactam antibiotics. This study provides novel perspectives into a bifunctional enzyme from L. garvieae, which can degrade ß-lactam antibiotics with high esterase activity.


Assuntos
Esterases , beta-Lactamases , Sequência de Aminoácidos , Antibacterianos/farmacologia , Cefotaxima , Esterases/química , Lactococcus , beta-Lactamases/química
12.
Microbiol Res ; 258: 126982, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35190348

RESUMO

Strains of the psychrotrophic bacterium Lactococcus piscium have gained increasing attention as potentially bioprotective cultures due to their assertiveness against fish and meat spoilage bacteria as well as pathogenic bacteria. Recently, we have described two novel species within the genus Lactococcus (Lc.) namely Lc. carnosus (TMW 2.1612T) and Lc. paracarnosus (TMW 2.1615T) isolated from modified atmosphere packaged meat. Within this study, we compared the genomes of two Lc. carnosus strains, two Lc. paracarnosus strains and 16 Lc. piscium strains from our laboratory and five publicly available genomes previously affiliated to the species Lc. piscium. Our phylogenetic analysis supports reclassification of 20 of the strains to either Lc. carnosus or Lc. paracarnosus, so far limiting the Lc. piscium type strain (DSM 6634T) as sole representative of this species. Comparative genomics approach was conducted to predict underlying mechanisms involved in interspecies competition strategies of Lc. carnosus and Lc. paracarnosus against meat spoilers and predict their lifestyle in meat environments. In general, strains of the three species were highly similar regarding metabolic pathways for most of the relevant meat-derived substrates. In silico analyses enabled prediction of homolactic hexose fermentation by Lc. carnosus, Lc. paracarnosus and Lc. piscium. Further, genes required for the heterofermentative metabolism of hexoses and pentoses were only found in the Lc. pisicum type strain (DSM 6634T). We predict a low spoilage potential for Lc. carnosus and Lc. paracarnosus strains. No genes for decarboxylation of amino acids yielding biogenic amines were found in the genomes. Regarding their antimicrobial mechanisms against spoilers, we found a strain-specific putative polymorphic toxin system predictively delivered by the type VIIb secretion system, enabling cell-to-cell contact-dependent growth inhibition. Furthermore, we found additional genes predictively involved to the suppression of spoilers within the food microbiome (prophages, lytic domains, bacteriocins, metabolites).


Assuntos
Anti-Infecciosos , Embalagem de Alimentos , Animais , Anti-Infecciosos/metabolismo , Microbiologia de Alimentos , Lactococcus , Carne/microbiologia , Filogenia
13.
Microb Genom ; 8(2)2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35196218

RESUMO

Lactococcus garvieae is a well-known pathogen of fish, but is rarely involved in infections in humans and other mammals. In humans, the main clinical manifestation of L. garvieae infections is endocarditis usually related to the ingestion of contaminated food, such as undercooked fish and shellfish. This study presents the first complete genomic sequence of a clinical L. garvieae strain isolated from a patient with endocarditis and its comparative analysis with other genomes. This human isolate contains a circular chromosome of 2 099 060 bp and one plasmid of 50 557 bp. In comparison with other fully sequenced L. garvieae strains, the chromosomal DNA of L. garvieae Lg-Granada carries a low proportion of insertion sequence elements and a higher number of putative prophages. Our results show that, in general, L. garvieae is a highly recombinogenic species with an open pangenome in which almost 30 % of its genome has undergone horizontal transfers. Within the genus Lactococcus, L. lactis is the main donor of genetic components to L. garvieae but, taking Lg-Granada as a representative, this bacterium tends to import more genes from Bacilli taxa than from other Lactococcus species.


Assuntos
Endocardite , Lactococcus , Animais , Evolução Biológica , Genômica/métodos , Humanos , Lactococcus/genética , Mamíferos
14.
World J Microbiol Biotechnol ; 38(2): 25, 2022 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-34989904

RESUMO

A total of 272 isolates of lactic acid bacteria (LAB) were isolated from 22 samples of naturally fermented milk products of Sikkim in India viz. dahi, soft-variety chhurpi, hard-variety chhurpi, mohi and philu, out of which, 68 LAB isolates were randomly grouped on the basis of phenotypic characteristics, and were identified by 16S rRNA gene sequence analysis. Leuconostoc mesenteroides was the most dominant genus, followed by Leuc. mesenteroides subsp. jonggajibkimchii, Lactococcus lactis subsp. cremoris, Lc. lactis, Lc. lactis subsp. hordniae, Lc. lactis subsp. tructae, Enterococcus faecalis, E. italicus and E. pseudoavium. LAB strains were tested for probiotics attributes by in vitro and genetic screening, based on marker genes. LAB strains showed tolerance to pH 3.0, bile salt, resistance to lysozyme and ß-galactosidase activity. Enterococcus faecalis YS4-11 and YS4-14 and Lactococcus lactis subsp. cremoris SC3 showed more than 85% of hydrophobicity. Genes clp L and tdc encoding for low pH tolerance, agu A and Ir1516 encoding for bile tolerance, LBA1446 gene encoding for BSH activity, map A, apf, mub 1 and msa encoding for mucosal binding property were detected. Gene mesY for bacteriocin production was detected only in Leuconostoc spp. Based on the in vitro and genetic screening of probiotic attributes, Leuc. mesenteroides; Leuc. mesenteroides subsp. jonggajibkimchii and Lc. lactis subsp. cremoris were tentatively selected for possible probiotic candidates.


Assuntos
Produtos Fermentados do Leite/microbiologia , Fermentação , Testes Genéticos , Lactobacillales/classificação , Lactobacillales/genética , Lactobacillales/isolamento & purificação , Probióticos , Animais , Bactérias/isolamento & purificação , Bacteriocinas , Bovinos , Enterococcus faecalis , Feminino , Microbiologia de Alimentos , Índia , Lactococcus , Leuconostoc/isolamento & purificação , Leite , Filogenia , RNA Ribossômico 16S/genética , Siquim
15.
J Dairy Sci ; 105(3): 2069-2081, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35033338

RESUMO

Traditionally, starter cultures for Cheddar cheese are combinations of Lactococcus lactis and Lactococcus cremoris. Our goal was to compare growth and survival of individual strains during cheesemaking, and after salting and pressing. Cultures used were 2 strains of L. lactis (SSM 7605, SSM 7436) and 2 strains of L. cremoris (SSM 7136, SSM 7661). A standardized Cheddar cheese make procedure was used that included a 38°C cook temperature and salting levels of 2.0, 2.4, 2.8, 3.2, and 3.6% from which were selected cheeses with salt-in-moisture levels of 3.5, 4.5, and 5.5%. Vats of cheese were made using each strain on its own as biological duplicates on different days. Starter culture numbers were enumerated by plate counting during cheesemaking and after 6 d storage at 6°C. Flow cytometry with fluorescent staining by SYBR Green and propidium iodide was used to determine the number of live and dead cells in cheese at the different salt levels. Differences in cheese make times were strain dependent rather than species dependent. Even with correction for average culture chain length, cheeses made using L. lactis strains contained ∼4 times (∼0.6 log) more bacterial cells than those made using L. cremoris strains. Growth of the strains used in this study was not influenced by the amount of salt added to the curd. The higher pH of cheeses with higher salting levels was attributed to those cheeses having a lower moisture content. Based on flow cytometry, ∼5% of the total starter culture cells in the cheese were dead after 6 d of storage. Another 3 to 19% of the cells were designated as being live, but semipermeable, with L. cremoris strains having the higher number of semipermeable cells.


Assuntos
Queijo , Lactococcus lactis , Animais , Queijo/microbiologia , Lactococcus , Cloreto de Sódio , Cloreto de Sódio na Dieta
16.
J Dairy Sci ; 105(1): 140-153, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34756439

RESUMO

A multiparameter study was performed to evaluate the effect of fondaco, a traditional ripening cellar without any artificial temperature and relative humidity control, on the chemical, microbiological, and sensory characteristics of Protected Geographical Indication Canestrato di Moliterno cheese. Ripening in such a nonconventional environment was associated with lower counts of lactococci, lactobacilli, and total viable bacteria, and higher presence of enterococci, in comparison with ripening in a controlled maturation room. Moreover, fondaco cheese underwent accelerated maturation, as demonstrated by faster casein degradation, greater accumulation of free AA, and higher formation of volatile organic compounds. Secondary proteolysis, as assessed by liquid chromatography-mass spectrometry of free AA and low molecular weight peptides, did not show any qualitative difference among cheeses, but fondaco samples evidenced an advanced level of peptidolysis. On the other hand, significant qualitative differences were observed in the free fatty acid profiles and in the sensory characteristics. Principal component analysis showed a clear separation of the fondaco and control cheeses, indicating that ripening in the natural room conferred unique sensory features to the product.


Assuntos
Queijo , Animais , Caseínas/metabolismo , Queijo/análise , Manipulação de Alimentos , Lactobacillus/metabolismo , Lactococcus/metabolismo , Proteólise
17.
Appl Environ Microbiol ; 88(2): e0193921, 2022 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-34757819

RESUMO

The aim of this study was to investigate the temporal stability of microbial contamination during cheddar cheese production by examining patterns of nonstarter bacteria in 60-day aged cheddar collected from the start and end of 30 consecutive production days. Further, we explored the source of these temporal microbial variations by comparing microbial communities in the aged cheese to those on food contact surfaces from a piece of cheesemaking equipment previously identified as a major source of nonstarter bacteria in the same processing environment. 16S rRNA metabarcoding and culture-based sequencing methods identified two Streptococcus sequence variants significantly associated with the end of the production day in both the aged cheese and the cheese processing environment. Closer inspection of these sequence variants in the aged cheese over the 40-day sampling period revealed sinusoidal-like fluctuations in their relative ratios, which appeared to coincide with the Lactococcus starter rotation schedule. These results demonstrate that the microbial composition of finished cheese can vary according to the timing of processing within a production day. Further, our results demonstrate that time-of-day microbial differences in cheese can result from bacterial growth on food contact surfaces and that the composition of these microbial differences is subject to change day-to-day and may be linked to routine changes in the Lactococcus starter culture. IMPORTANCE Long production schedules used in modern cheese manufacturing can create circumstances that support the growth of microorganisms in the cheese processing environment. This work demonstrates that this growth can lead to significant changes in the microbial quality of aged cheese produced later in the production day. Further, we demonstrate that the dominant bacteria associated with these microbial changes throughout production are subject to change between days and might be influenced by specific cheese manufacturing practices. These findings improve understanding of microbial contamination patterns in modern food manufacturing facilities, thereby improving our ability to develop strategies to minimize quality losses due to microbial spoilage.


Assuntos
Queijo , Microbiota , Bactérias/genética , Queijo/microbiologia , Lactococcus , RNA Ribossômico 16S/genética
18.
J Appl Microbiol ; 132(2): 802-821, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34365708

RESUMO

The review deals with lactic acid bacteria in characterizing the stress adaptation with cross-protection effects, mainly associated with Lactobacillus, Bifidobacterium and Lactococcus. It focuses on adaptation and cross-protection in Lactobacillus, Bifidobacterium and Lactococcus, including heat shocking, cold stress, acid stress, osmotic stress, starvation effect, etc. Web of Science, Google Scholar, Science Direct, and PubMed databases were used for the systematic search of literature up to the year 2020. The literature suggests that a lower survival rate during freeze-drying is linked to environmental stress. Protective pretreatment under various mild stresses can be applied to lactic acid bacteria which may enhance resistance in a strain-dependent manner. We investigate the mechanism of damage and adaptation under various stresses including heat, cold, acidic, osmotic, starvation, oxidative and bile stress. Adaptive mechanisms include synthesis of stress-induced proteins, adjusting the composition of cell membrane fatty acids, accumulating compatible substances, etc. Next, we reveal the cross-protective effect of specific stress on the other environmental stresses. Freeze-drying is discussed from three perspectives including the regulation of membrane, accumulation of compatible solutes and the production of chaperones and stress-responsive proteases. The resistance of lactic acid bacteria against technological stress can be enhanced via cross-protection, which improves industrial efficiency concerning the survival of probiotics. However, the adaptive responses and cross-protection are strain-dependent and should be optimized case by case.


Assuntos
Lactobacillus , Probióticos , Bifidobacterium , Liofilização , Lactococcus
19.
Eur J Clin Nutr ; 76(4): 574-580, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34349248

RESUMO

BACKGROUND: Lactococcus lactis subsp. cremoris (YRC3780), which is isolated from kefir, has been associated with anti-allergic effects in humans. However, it remains unknown whether daily intake of YRC3780 attenuates the response to psychological stress in humans in parallel with changes to the gut microbiome. We examined the fundamental role of YRC3780 in the gut microbiome, stress response, sleep, and mental health in humans. METHODS: Effects of daily intake of YRC3780 on the hypothalamic-pituitary-adrenal (HPA) axis response to acute psychological stress were investigated in a double-blind, placebo-controlled clinical trial involving 27 healthy young men (mean age and body mass index: 23.5 years and 21.5 kg/m2) who were randomly assigned to placebo (n = 13) or YRC3780 (n = 14) groups. The HPA axis response to acute psychological stress, the diurnal rhythm of HPA axis activity, and gut microbiome were assessed and compared between the two groups. RESULTS: The results showed that daily intake of YRC3780 significantly lowered morning salivary cortisol levels compared with placebo. In addition, salivary cortisol levels following a social stress test significantly decreased +40 min after beginning the TSST in the YRC3780-treated group compared to placebo. There were no significant differences between the two groups in terms of actigraphy-based sleep quality, but the subjective sleep quality and mental health were significantly improved in the YRC3780-treated group compared to placebo. CONCLUSIONS: Our study suggests that daily intake of YRC3780 improves the HPA axis response to acute psychological stress, which might be associated with a decrease in morning cortisol levels.


Assuntos
Hidrocortisona , Sistema Hipotálamo-Hipofisário , Humanos , Sistema Hipotálamo-Hipofisário/fisiologia , Japão , Lactococcus , Masculino , Sistema Hipófise-Suprarrenal/fisiologia , Saliva , Estresse Psicológico/psicologia
20.
Dis Aquat Organ ; 147: 127-140, 2021 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-34913441

RESUMO

Tilapia lake virus (TiLV) and Lactococcus garvieae are 2 major pathogens of cultured Nile tilapia Oreochromis niloticus. In June-July 2018, a disease outbreak was reported in Nile tilapia cultured in brackish water floating cages in Kerala, India. Affected fish died gradually, and cumulative mortality reached ~75% within 1 mo. In the present study, TiLV and L. garvieae were isolated from the infected fish and confirmed. Nucleotide analysis of the partial sequence of segment 3 revealed that the present TiLV isolate showed 100% similarity with TiLV MF574205 and 97.65% similarity with TiLV KU552135 isolated in Israel. The partial 16S rDNA nucleotide sequence of L. garvieae shared 99% similarity with the 16S rDNA nucleotide sequence of L. garvieae isolated from Nile tilapia in Brazil. Eight virulence genes (hly1, hly2, hly3, NADH oxidase, adhPav, LPxTG-1, LPxTG-4, adhC1) were amplified in the present isolate. In the experimental challenge study, the onset of mortality started earlier in fish co-infected with TiLV and L. garvieae (3 d post-infection [dpi]) compared to other groups. Cumulative mortality (90% at 12 dpi) was significantly higher in the co-infected group than in fish infected with TiLV (60% at 12 dpi) and L. garvieae (40% at 12 dpi) alone. This study reveals that synergistic co-infection with TiLV and other bacteria may increase mortality in disease outbreaks. To the best of our knowledge, this is the first reported co-infection of L. garvieae with TiLV associated with mass mortality in Nile tilapia in India.


Assuntos
Ciclídeos , Coinfecção , Doenças dos Peixes , Tilápia , Animais , Coinfecção/veterinária , Doenças dos Peixes/epidemiologia , Lactococcus
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