RESUMO
Metabiotics are the structural components of probiotic bacteria, functional metabolites, and/or signaling molecules with numerous beneficial properties. A novel Lactococcus lactis strain, UTNCys6-1, was isolated from wild Amazonian camu-camu fruits (Myrciaria dubia), and various functional metabolites with antibacterial capacity were found. The genome size is 2,226,248 base pairs, and it contains 2248 genes, 2191 protein-coding genes (CDSs), 50 tRNAs, 6 rRNAs, 1 16S rRNA, 1 23S rRNA, and 1 tmRNA. The average GC content is 34.88%. In total, 2148 proteins have been mapped to the EggNOG database. The specific annotation consisted of four incomplete prophage regions, one CRISPR-Cas array, six genomic islands (GIs), four insertion sequences (ISs), and four regions of interest (AOI regions) spanning three classes of bacteriocins (enterolysin_A, nisin_Z, and sactipeptides). Based on pangenome analysis, there were 6932 gene clusters, of which 751 (core genes) were commonly observed within the 11 lactococcal strains. Among them, 3883 were sample-specific genes (cloud genes) and 2298 were shell genes, indicating high genetic diversity. A sucrose transporter of the SemiSWEET family (PTS system: phosphoenolpyruvate-dependent transport system) was detected in the genome of UTNCys6-1 but not the other 11 lactococcal strains. In addition, the metabolic profile, antimicrobial susceptibility, and inhibitory activity of both protein-peptide extract (PPE) and exopolysaccharides (EPSs) against several foodborne pathogens were assessed in vitro. Furthermore, UTNCys6-1 was predicted to be a non-human pathogen that was unable to tolerate all tested antibiotics except gentamicin; metabolized several substrates; and lacks virulence factors (VFs), genes related to the production of biogenic amines, and acquired antibiotic resistance genes (ARGs). Overall, this study highlighted the potential of this strain for producing bioactive metabolites (PPE and EPSs) for agri-food and pharmaceutical industry use.
Assuntos
Bacteriocinas , Lactococcus lactis , Frutas/química , Lactococcus lactis/genética , Lactococcus lactis/metabolismo , RNA Ribossômico 16S/genética , Sequência de Bases , Bacteriocinas/metabolismo , Antibacterianos/metabolismoRESUMO
BACKGROUND: Lactococcus lactis strain pGSMT/MG1363 is a genetically modified microorganism (GMM) that constitutively expresses human metallothionein-I fusion protein to combine with intracellular lead. Unlike traditional probiotics, pGSMT/MG1363 lacks a history of safe use in food. Administration of microorganism could influence the gut microbial community and consequently confer health benefits or cause disadvantages to the host. To date, little has been done to assess the influence of recombinant strain pGSMT/MG1363 on the stability of gut microbiota. RESULTS: Liver, testis and kidney sections of male Sprague-Dawley rats orally administered pGSMT/MG1363 for 6 weeks showed normal structure and no pathological damage. There were no adverse effects on the analyzed serum biochemical parameters between the pGSMT/MG1363 group and the MG1363 group. Principal coordinate analysis showed that, compared with the MG1363 group, the 6-week-old fecal gut microbiota of rats fed with pGSMT/MG1363 was not significantly different (Adonis, P = 0.802). pGSMT/MG1363 treatment for 6 weeks did not significantly change the relative abundance of gut microbiota at the phylum and genus levels in comparison with MG1363 treatment. CONCLUSION: Compared to the non-GM strain MG1363 group, administration of the recombinant strain pGSMT/MG1363 for 6 weeks showed no adverse effects on the analyzed physiological parameters and gut microbial compositions of male Sprague-Dawley rats. The results suggested that, in terms of gut microbiota stability, pGSMT/MG1363 could be considered as safe as MG1363, at least for short-term intake. Further toxicological evaluations still need to be considered before drawing a definite conclusion concerning the safe use of pGSMT/MG1363. © 2021 Society of Chemical Industry.
Assuntos
Microbioma Gastrointestinal/efeitos dos fármacos , Lactococcus lactis/genética , Probióticos/administração & dosagem , Animais , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Avaliação Pré-Clínica de Medicamentos , Fezes/microbiologia , Rim/metabolismo , Rim/patologia , Lactococcus lactis/metabolismo , Fígado/metabolismo , Fígado/patologia , Masculino , Metalotioneína/genética , Metalotioneína/metabolismo , Probióticos/efeitos adversos , Probióticos/metabolismo , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismoRESUMO
CRISPR-Cas9 is widely used in genomic editing, but the kinetics of target search and its relation to the cellular concentration of Cas9 have remained elusive. Effective target search requires constant screening of the protospacer adjacent motif (PAM) and a 30 ms upper limit for screening was recently found. To further quantify the rapid switching between DNA-bound and freely-diffusing states of dCas9, we developed an open-microscopy framework, the miCube, and introduce Monte-Carlo diffusion distribution analysis (MC-DDA). Our analysis reveals that dCas9 is screening PAMs 40% of the time in Gram-positive Lactoccous lactis, averaging 17 ± 4 ms per binding event. Using heterogeneous dCas9 expression, we determine the number of cellular target-containing plasmids and derive the copy number dependent Cas9 cleavage. Furthermore, we show that dCas9 is not irreversibly bound to target sites but can still interfere with plasmid replication. Taken together, our quantitative data facilitates further optimization of the CRISPR-Cas toolbox.
Assuntos
Proteína 9 Associada à CRISPR/metabolismo , Edição de Genes , Microscopia/métodos , Plasmídeos/genética , Imagem Individual de Molécula/métodos , Proteína 9 Associada à CRISPR/genética , Dosagem de Genes , Lactococcus lactis/genética , Lactococcus lactis/metabolismo , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Microscopia/instrumentação , Modelos Genéticos , Método de Monte Carlo , Motivos de Nucleotídeos/genética , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Imagem Individual de Molécula/instrumentação , Fatores de Tempo , Proteína Vermelha FluorescenteRESUMO
Nowadays, cancer remains a major cause of death affecting millions of people. Currently, the antimicrobial peptides (AMPs) as potent anticancer therapeutic agents offer specificity and low levels of side effects in cancer therapy. In the present study, a cationic chimeric peptide (cLFchimera), derived from camel lactoferrin, was expressed as a secretory peptide using P170 expression system in L. lactis. Peptide purification was carried out using Ni-NTA agarose column from culture medium with 21 µ/mL concentration. The recombinant peptide was investigated for its activity against four tumor and one normal cell line. The cLFchimera was more active against two tumor cell lines (chondrosarcoma and colorectal cancer cells), but the activity against two other tumor cell lines (hepatoma and breast cancer cell line) and normal cells was low. Finally, to have better insight into the mode of action of the peptide on cytotoxic activity, we examined the interaction of cationic peptide with two glycosaminoglycans (GAGs), heparan sulfate (HS) and chondroitin sulfate (CS), as the two most anionic molecules on the cell surface by molecular dynamic simulation. The results of in silico analysis showed that the cLFchimera interacted with HS and CS with a totally different amino acid profile. Hydrogen bonding screening in GAGs-peptide complexes revealed K21, V23 and I3, R16 are the dominant amino acids involved in peptide-HS and CS interaction, respectively. Overall, the results of this investigation showed the P170 expression system successfully expressed a cationic peptide with potent anticancer activity. Moreover, molecular docking analysis revealed the pattern of peptide interaction with negatively charged membrane molecules.
Assuntos
Membrana Celular/efeitos dos fármacos , Glicosaminoglicanos/metabolismo , Lactococcus lactis/metabolismo , Peptídeos/química , Peptídeos/farmacologia , Animais , Antibacterianos/química , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Antineoplásicos/química , Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , Camelus , Linhagem Celular Tumoral , Membrana Celular/química , Membrana Celular/metabolismo , Expressão Gênica , Glicosaminoglicanos/química , Humanos , Lactococcus lactis/genética , Lactoferrina/química , Simulação de Acoplamento Molecular , Peptídeos/genética , Peptídeos/metabolismoRESUMO
Adhesion of Staphylococcus aureus to endothelial cells (ECs) is paramount in infective endocarditis. Bacterial proteins such as clumping factor A (ClfA) and fibronectin binding protein A (FnbpA) mediate adhesion to EC surface molecules and (sub)endothelial matrix proteins including fibrinogen (Fg), fibrin, fibronectin (Fn) and von Willebrand factor (vWF). We studied the influence of shear flow and plasma on the binding of ClfA and FnbpA (including its sub-domains A, A16+, ABC, CD) to coverslip-coated vWF, Fg/fibrin, Fn or confluent ECs, making use of Lactococcus lactis, expressing these adhesins heterologously. Global adherence profiles were similar in static and flow conditions. In the absence of plasma, L. lactis-clfA binding to Fg increased with shear forces, whereas binding to fibrin did not. The degree of adhesion of L. lactis-fnbpA to EC-bound Fn and of L. lactis-clfA to EC-bound Fg, furthermore, was similar to that of L. lactis-clfA to coated vWF domain A1, in the presence of vWF-binding protein (vWbp). Yet, in plasma, L. lactis-clfA adherence to activated EC-vWF/vWbp dropped over 10 minutes by 80% due to vWF-hydrolysis by a disintegrin and metalloproteinase with thrombospondin type 1 motif, member 13 and that of L. lactis-fnbpA likewise by > 70% compared to the adhesion in absence of plasma. In contrast, plasma Fg supported high L. lactis-clfA binding to resting and activated ECs. Or, in plasma S. aureus adhesion to active endothelium occurs mainly via two complementary pathways: a rapid but short-lived vWF/vWbp pathway and a stable integrin-coupled Fg-pathway. Hence, the pharmacological inhibition of ClfA-Fg interactions may constitute a valuable additive treatment in infective endocarditis.
Assuntos
Proteína ADAMTS13/sangue , Aderência Bacteriana , Coagulase/metabolismo , Endocardite Bacteriana/microbiologia , Células Endoteliais da Veia Umbilical Humana/microbiologia , Plasma/enzimologia , Staphylococcus aureus/metabolismo , Adesinas Bacterianas/genética , Adesinas Bacterianas/metabolismo , Células Cultivadas , Coagulase/genética , Endocardite Bacteriana/sangue , Fibrina/metabolismo , Fibrinogênio , Fibronectinas/metabolismo , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Lactococcus lactis/genética , Lactococcus lactis/metabolismo , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Staphylococcus aureus/genética , Estresse Mecânico , Fator de von Willebrand/metabolismoRESUMO
Protein investment costs are considered a major driver for the choice of alternative metabolic strategies. We tested this premise in Lactococcus lactis, a bacterium that exhibits a distinct, anaerobic version of the bacterial Crabtree/Warburg effect; with increasing growth rates it shifts from a high yield metabolic mode [mixed-acid fermentation; 3 adenosine triphosphate (ATP) per glucose] to a low yield metabolic mode (homolactic fermentation; 2 ATP per glucose). We studied growth rate-dependent relative transcription and protein ratios, enzyme activities, and fluxes of L. lactis in glucose-limited chemostats, providing a high-quality and comprehensive data set. A three- to fourfold higher growth rate rerouted metabolism from acetate to lactate as the main fermentation product. However, we observed hardly any changes in transcription, protein levels and enzyme activities. Even levels of ribosomal proteins, constituting a major investment in cellular machinery, changed only slightly. Thus, contrary to the original hypothesis, central metabolism in this organism appears to be hardly regulated at the level of gene expression, but rather at the metabolic level. We conclude that L. lactis is either poorly adapted to growth at low and constant glucose concentrations, or that protein costs play a less important role in fitness than hitherto assumed.
Assuntos
Glucose/metabolismo , Lactococcus lactis/crescimento & desenvolvimento , Lactococcus lactis/metabolismo , Proteínas Ribossômicas/metabolismo , Ribossomos/metabolismo , Acetatos/metabolismo , Trifosfato de Adenosina/metabolismo , Arginina/metabolismo , Bactérias Anaeróbias/metabolismo , Fermentação , Glicólise , Cinética , Ácido Láctico/metabolismo , Lactococcus lactis/enzimologia , Lactococcus lactis/genética , Proteínas Ribossômicas/biossínteseRESUMO
We present a simple and rapid method for screening nisin producers that directly identifies nisinogenic bacteria by induction of bioluminescence within the Lactococcus lactis NZ9800lux biosensor strain (Immonen and Karp, 2007, Biosensors and Bioelectronics 22, 1982-7). An overlay of putative nisinogenic colonies with the biosensor strain gives identification results within 1h. Functionality and specificity of the method were verified by screening nisin producers among 144 raw milk colonies and a panel of 91 lactococcal strains. Studies performed on strains and colonies that did not induce bioluminescence but inhibited growth of the biosensor demonstrated that only nisinogenic bacteria can cause induction. Bacteria known to produce bacteriocins other than nisin failed to induce bioluminescence, further verifying the specificity of the assay. We discovered a non-inducing but inhibitory lactococcal strain harboring a modified nisin Z gene, and demonstrated that the source of the inhibitory action is not a non-inducing variant of nisin, but a bacteriocin of lower molecular weight. The concentration of nisin producers in a raw milk sample was 1.3 × 10(2)CFU/ml. We identified from raw milk a total of seven nisin Z producing L. lactis subsp. lactis colonies, which were shown by genetic fingerprinting to belong to three different groups. Among the panel of 91 lactococci, four strains were nisin A producers, and one strain harbored the modified nisin Z gene. The method presented here is robust, cost-effective and simple to perform, and avoids the pitfalls of traditional screening methods by directly specifying the identity of the inhibitory substance.
Assuntos
Bactérias/metabolismo , Técnicas Biossensoriais/métodos , Lactococcus lactis/genética , Leite/microbiologia , Nisina/biossíntese , Animais , Bacteriocinas , Técnicas Biossensoriais/economia , Lactococcus/efeitos dos fármacos , Lactococcus lactis/efeitos dos fármacos , Nisina/análogos & derivados , Nisina/genéticaRESUMO
Using the yeast two-hybrid system, intraspecific protein interactions were detected in Streptococcus iniae and Lactococcus lactis subsp. cremoris between the transmembrane activation protein (CpsC and EpsA, respectively) and the protein tyrosine kinase (CpsD and EpsB, respectively), between two protein tyrosine kinases, and between the protein tyrosine kinase and the phosphotyrosine phosphatase (CpsB and EpsC, respectively). For each of these intraspecific interactions, interspecific interactions were also detected when one protein was from S. iniae and the other was from Streptococcus thermophilus . Interactions were also observed between two protein tyrosine kinases when one protein was from either of the Streptococcus species and the other from L. lactis subsp. cremoris. The results and sequence comparisons performed in this study support the conclusion that interactions among the components of the tyrosine kinase - phosphatase regulatory system are conserved in the order Lactobacillales and that interspecific genetic exchanges of the genes that encode these proteins have the potential to form functional recombinants. A better understanding of intraspecific and interspecific protein interactions involved in regulating exopolysaccharide biosynthesis may facilitate construction of improved strains for industrial uses as well as identification of factors needed to form functional regulatory complexes in naturally occurring recombinants.
Assuntos
Proteínas de Bactérias/metabolismo , Transferência Genética Horizontal , Lactococcus lactis , Streptococcus thermophilus , Streptococcus , Sequência de Aminoácidos , Cápsulas Bacterianas/biossíntese , Cápsulas Bacterianas/genética , Cápsulas Bacterianas/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Enzimas/química , Enzimas/metabolismo , Lactococcus lactis/genética , Lactococcus lactis/metabolismo , Dados de Sequência Molecular , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Especificidade da Espécie , Streptococcus/genética , Streptococcus/metabolismo , Streptococcus thermophilus/genética , Streptococcus thermophilus/metabolismo , Técnicas do Sistema de Duplo-HíbridoRESUMO
The intrasubspecies diversity of six strains of Lactococcus lactis subsp. lactis was investigated at the genomic level and in terms of phenotypic and transcriptomic profiles in an ultrafiltration cheese model. The six strains were isolated from various sources, but all exhibited a dairy phenotype (growth in ultrafiltration cheese model and high acidification rate). The six strains exhibited similar behaviors in terms of growth during cheese ripening, while different acidification capabilities were detected. Even if all strains displayed large genomic similarities, sharing a large core genome of almost 2,000 genes, the expression of this core genome directly in the cheese matrix revealed major strain-specific differences that potentially could account for the observed different acidification capabilities. This work demonstrated that significant transcriptomic polymorphisms exist even among Lactococcus lactis subsp. lactis strains with the same dairy origin.
Assuntos
Técnicas de Tipagem Bacteriana , Queijo/microbiologia , Variação Genética , Lactococcus lactis/classificação , Lactococcus lactis/genética , Hibridização Genômica Comparativa , Perfilação da Expressão Gênica , Genoma Bacteriano , Genômica , Genótipo , Concentração de Íons de Hidrogênio , Lactococcus lactis/isolamento & purificação , Lactococcus lactis/metabolismo , Dados de Sequência Molecular , Análise de Sequência com Séries de Oligonucleotídeos , Fenótipo , Reação em Cadeia da Polimerase , Especificidade da EspécieRESUMO
Plate, filter and broth mating techniques were assessed over a range of pHs using three Lactococcus lactis donor strains (one with an erythromycin resistance marker and two with tetracycline resistance markers, all located on transferable genetic elements) and one L. lactis recipient strain. Transconjugants were confirmed using antibiotic selection, E-tests to determine MICs, PCR assays to detect the corresponding marker genes, DNA fingerprinting by pulsed-field gel electrophoresis (PFGE), and Southern blotting. Horizontal gene transfer (HGT) rates varied (ranging from 1.6 x 10(-1) to 2.3 x 10(-8)). The general trend observed was plate > filter > broth, independent of pH. Our data suggests that standardisation of methodologies to be used to assess HGT, is warranted and would provide a meaningful assessment of the ability of commensal and other bacteria in different environments to transfer relevant markers.
Assuntos
Conjugação Genética , Técnicas de Transferência de Genes , Transferência Genética Horizontal , Lactococcus lactis/genéticaRESUMO
BACKGROUND: In research laboratories using DNA-microarrays, usually a number of researchers perform experiments, each generating possible sources of error. There is a need for a quick and robust method to assess data quality and sources of errors in DNA-microarray experiments. To this end, a novel and cost-effective validation scheme was devised, implemented, and employed. RESULTS: A number of validation experiments were performed on Lactococcus lactis IL1403 amplicon-based DNA-microarrays. Using the validation scheme and ANOVA, the factors contributing to the variance in normalized DNA-microarray data were estimated. Day-to-day as well as experimenter-dependent variances were shown to contribute strongly to the variance, while dye and culturing had a relatively modest contribution to the variance. CONCLUSION: Even in cases where 90% of the data were kept for analysis and the experiments were performed under challenging conditions (e.g. on different days), the CV was at an acceptable 25%. Clustering experiments showed that trends can be reliably detected also from genes with very low expression levels. The validation scheme thus allows determining conditions that could be improved to yield even higher DNA-microarray data quality.