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Lactococcus

Lactococcus is a genus of Gram-positive, catalase-negative, non-spore-forming, coccus-shaped bacteria commonly found in dairy products and the human gastrointestinal tract.
These bacteria are important in the production of fermented dairy foods, such as cheese and yogurt, due to their ability to convert lactose into lactic acid.
Lactococcus species are also studied for their potential probiotic properties and their role in the human microbiome.
Researchers can optimize their Lactococcus research using the AI-driven platform PubCompare.ai, which helps locate the best protocols from literature, preprints, and patents, and improve reproducibility and accuracy through intelligent analysis.
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Most cited protocols related to «Lactococcus»

1
Temperature-sensitive vector for allelic replacement in Staphylococcus aureus
A new temperature-sensitive vector was constructed for allelic replacement mutagenesis in S. aureus. The vector is based on the replicon of the lactococcal plasmid pWV01ts (from pVE6007 [21 (link)]) rather than the commonly used staphylococcal pE194ts replicon (30 (link)). A hybrid vector (pIMC5) was created by spliced overlap extension (SOE) PCR. It comprises (i) the repBCAD(Ts) genes from pVE6007 and (ii) the E. coli backbone p15A rep and pBluescript KS multiple cloning site and the highly expressed chloramphenicol acyltransferase marker from pIMC (31 (link)). The counterselection marker encoding tetracycline-inducible antisense secY RNA was amplified from pKOR1 and introduced between the novel BglII and SphI sites to form pIMAY.
Monk I.R., Shah I.M., Xu M., Tan M.W, & Foster T.J. (2012). Transforming the Untransformable: Application of Direct Transformation To Manipulate Genetically Staphylococcus aureus and Staphylococcus epidermidis. mBio, 3(2), e00277-11.
Publication 2012
Alleles Antisense RNA Chloramphenicol O-Acetyltransferase Cloning Vectors Escherichia coli Genes Hybrids Lactococcus Mutagenesis Plasmids Replicon Staphylococcus Staphylococcus aureus Tetracycline Vertebral Column
2
Construction of CovR/CovS-complemented GAS Strain
Plasmid pMW506, the covR gene interrupted by a chloramphenicol cassette via the MslI site on E. coli vector pSF152, was provided by Prof. Jiunn Jong Wu. The plasmid pMW506 was electroporated into A20 and AP3 by the method described previously (Chiang-Ni et al., 2008 (link)) to interrupt the covR gene by a double-cross homologous recombination (designed SW656 and SW934, respectively).
To construct covR/covS-complemented strain, the covR/S allele (2505 bp, including promoter region) was amplified from wild type A20 strain using primers CovR/S-F-3 and CovR/S-R-2 (Table 2) and ligated into the BamHI site of E. coli-GAS shuttle vector pTRKL2 to create pCN111. The plasmid pTRKL2 was kindly provided by T. R. Klaenhammer (Department of Food Science, Southeast Dairy Foods Research Center, North Carolina State University, Raleigh, USA). The backbone of pTRKL2 is a pAMß1-derived Gram-positive vector pIL252. The copy number of pTRKL2 is corresponded to pIL252, which is 6-9 copies in a streptococcal and lactococcal host and 30-40 copies in E. coli (O’Sullivan and Klaenhammer, 1993 (link)). The plasmid pCN111 and vector pTRKL2 were electroporated into AP3 to generate the covR/S-complemented strain (SCN121) and vector control strain (SCN127).
Chiang-Ni C., Chu T.P., Wu J.J, & Chiu C.H. (2016). Repression of Rgg But Not Upregulation of LacD.1 in emm1-type covS Mutant Mediates the SpeB Repression in Group A Streptococcus. Frontiers in Microbiology, 7, 1935.
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Publication 2016
Alleles Chloramphenicol Cloning Vectors Escherichia coli Food Genes Genes, Duplicate Homologous Recombination Lactococcus Oligonucleotide Primers Plasmids Shuttle Vectors Strains Streptococcus Vertebral Column
3
Curated Phage Structural Protein Databases
In this work, we generated two complementary protein databases, "classes" and "others". The "classes" database contains curated sequences of ten phage structural functions (Major capsid, Minor capsid, Baseplate, Major tail, Minor tail, Portal, Tail fiber, Tail sheath, Collar, and Head-Tail Joining). These functional classes are not exhaustive (and we will add more classes in the future); they represent the dominant structural protein roles present in most (but not all) phages [13 (link)]. The terms/descriptors for these classes are addressed in the next section. Major capsid proteins are those that form the phage head. Many but not all phages also encode minor capsid proteins that decorate and/or stabilize the head or proteins present at the vertices of the icosahedral heador at the center of the hexon faces. Portals form a ring at the base of the phage head and serve to dock the packaging complex that translocates the genome into the phage head. Head-tail joining (aka head-tail connector or head completion) proteins form rings inserted between the portal ring and the tail. The collar is present in some phages, e.g. the Lactococcal phages, at the base of the neck/top of the tail to which the so-called whiskers attach. Major tail proteins form the inner tail tube of the tailed phages, whereas the tail sheath (aka the tail shaft) proteins form the outside of the tail, and permit contraction. Minor tail proteins may comprise several kinds of proteins associated with the tail, including the tape measure protein. Baseplate proteins are those that are attached to the tail and to which the tail fibers are attached, the latter being a relatively common determinant of host range. The "others" database contains all phage ORFs that do not encode proteins annotated as “structural” or as any of the ten categories above.
Cantu V.A., Salamon P., Seguritan V., Redfield J., Salamon D., Edwards R.A, & Segall A.M. (2020). PhANNs, a fast and accurate tool and web server to classify phage structural proteins. PLoS Computational Biology, 16(11), e1007845.
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Publication 2020
Bacteriophages Capsid Proteins Caudovirales Face Fibrosis Genome Head Hexamethonium Host Range Lactococcus Neck Open Reading Frames Proteins Rumex Tail Vibrissae
4
Recombinant Lactococcus lactis Secretion
To create the secretion vector for L. lactis, the sequence of usp45, the lactococcal signal peptide, was inserted into pNZ8148#2:CYT [13 (link)] between the nisin-inducible promoter (Pnis) and 6x His-tag sequences; the resulting plasmid was designated pNZ8148#2:SEC (Figure 1(a)). The pNZ8148#2:CYT vector is a modified form of the L. lactis expression vector pNZ8148 (MoBiTec).
The gene encoding BLG (accession number: EU883598) was synthesized and subcloned into pGEM-T easy optimized for MG1363 codon-usage by Eurofins Genomics (Tokyo, Japan). The sequence of the BLG gene was subsequently cloned between the KpnI and HindIII restriction sites in pNZ8148#2:SEC, generating pNZ8148#2:SEC-BLG (Figure 1(b)).
The pNZ8148#2:SEC-BLG vector was introduced into NZ9000 by electroporation using a Gene Pulser Xcell electroporation system (Bio-Rad Laboratories Inc., CA, USA) following the manufacturer's instructions. The resulting recombinant strain was designated NZ9000:SEC-BLG. NZ9000 was also electroporated with the empty plasmid pNZ8148#2:SEC to generate an NZ9000 vector control strain (NZ9000:SEC-VC).
Shigemori S., Oshiro K., Wang P., Yamamoto Y., Wang Y., Sato T., Uyeno Y, & Shimosato T. (2014). Generation of Dipeptidyl Peptidase-IV-Inhibiting Peptides from β-Lactoglobulin Secreted by Lactococcus lactis. BioMed Research International, 2014, 393598.
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Publication 2014
Cloning Vectors Codon Usage Electroporation Genes Genitalia Lactation Lactococcus L Forms nisin A Plasmids prostaglandin M Signal Peptides Strains
5
Cultivation and Transformation of Lactobacilli and Lactococci
Bacterial strains and plasmids used in this study are listed in Supplementary Table S1. Lactobacilli and their derivatives were cultured under anaerobic conditions at 37°C in deMan Rogosa Sharpe (MRS) medium (Difco, BD BioSciences). Lactococcus and its derivatives were cultured static at 30°C in M17-broth (Difco, BD BioSciences) that was supplemented with glucose to a final concentration of 0.5% (w/v). Electrocompetent cells of lactobacilli and Lactococcus were prepared as described before (28–30 ). If required, antibiotics were added as follows: 5 µg/ml erythromycin or chloramphenicol for lactobacilli and Lactococcus, 25 and 50 µg/ml rifampicin for lactobacilli and lactococci, respectively.
van Pijkeren J.P, & Britton R.A. (2012). High efficiency recombineering in lactic acid bacteria. Nucleic Acids Research, 40(10), e76.
Publication 2012
Antibiotics, Antitubercular Bacteria Cells Chloramphenicol derivatives Erythromycin Glucose Lactobacillus Lactococcus Plasmids Rifampin Strains

Most recents protocols related to «Lactococcus»

1
Microbial and Metabolomic Dynamics of Artisanal Cheese
All statistical analyses were performed in R (version 4.1.0; R Core Team, 2021 ). One-way analysis of variance (ANOVA) was performed to compare differences in relative abundances of bacteria between starter culture rotations and ripening times, followed by post-hoc pairwise comparisons with Tukey’s test. A principal component analysis (PCA) was performed to compare species compositions of all cheese samples at all time points. A scaled PCA (Z-score transformation) was performed to compare Lactococcus ASVs at 36 weeks of ripening among batches and to compare all metabolites at 36, 45, 75, and 100 weeks of ripening, in each case between cores and rinds. For correlation analysis, only species with an average relative abundance of ≥0.2% across all cheese cores after 36, 45, 75, and 100 weeks of ripening were considered. Spearman correlation coefficients were calculated when data from different ripening times were used, whereas Pearson correlation coefficients were calculated for correlations with the sensory score at one ripening time. Spearman correlations between species and metabolites were visualized in a heatmap using the ComplexHeatmap package (version 2.0.0; Gu et al., 2016 (link)). Hierarchical clustering analysis was based on the Ward’s method (clustering method set to “Ward.D2”). For all statistical tests, results with a p-value < 0.05 were considered significantly different.
Microbial intra-sample diversity (alpha diversity) was assessed by calculating the inverse Simpson diversity index, applying the vegan package (version 2.5–7; Oksanen et al., 2020 ). Microbial inter-sample diversity (beta diversity) was assessed by conducting a permutational multivariate analysis of variance (PERMANOVA), based on Bray–Curtis dissimilarity scores, applying the RVAideMemoire package (version 0.9–80; Hervé, 2021 ).
Decadt H., Weckx S, & De Vuyst L. (2023). The rotation of primary starter culture mixtures results in batch-to-batch variations during Gouda cheese production. Frontiers in Microbiology, 14, 1128394.
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Publication 2023
asunaprevir Bacteria Cheese Lactococcus Vegan
2
Imaging Lactococcal Cell Morphology
Phase contrast images of lactococcal cells from overnight cultures in GM17 were observed with a 100× phase contrast objective lens in a DMi8 (Leica) microscope equipped with a Leica DFC365FX camera.
Escobedo S., Campelo A.B., Umu Ö.C., López-González M.J., Rodríguez A., Diep D.B, & Martínez B. (2023). Resistance to the Bacteriocin Lcn972 Deciphered by Genome Sequencing. Microorganisms, 11(2), 501.
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Publication 2023
Cells Lactococcus Lens, Crystalline Microscopy Microscopy, Phase-Contrast
3
Microbiological Characterization of Curdled Milk
At each sampling point, 1 g of curdled milk was mixed in 9 mL of sterile 0.1% peptone solution in a Stomacher Lab-Blender 400 (Seward Medical, UK) for 1 min under aseptic conditions. Serial dilutions were prepared for bacterial density determination. To determine total aerobic bacteria (TAB), the growth was carried out in a PC agar medium after 72 h of incubation at 30 °C [32 ]. MRS and M17 agar were used to enumerate Lactobacillus spp. and Lactococcus spp. after anaerobic incubation at 37 °C for 72 h, respectively. Regarding yeasts and molds, the incubation was performed in supplemented RBCA medium for 3 to 5 days at 25 °C, while Enterobacteriaceae were enumerated in VRBGA after 24 h at 37 °C. BPA supplemented with egg folk tellurite emulsion was used to grow Stapylococcus spp. at 37 °C for 48 h [33 ]. Microbial count determinations were duplicated, and the results were expressed in the log (CFU g−1).
During all sampling points, the pH of the model systems was also monitored using a pH meter (Micro pH 2002, Crison, Barcelona, Spain) in triplicate.
Araújo-Rodrigues H., Martins A.P., Tavaria F.K., Dias J., Santos M.T., Alvarenga N, & Pintado M.E. (2023). Impact of LAB from Serpa PDO Cheese in Cheese Models: Towards the Development of an Autochthonous Starter Culture. Foods, 12(4), 701.
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Publication 2023
Agar Asepsis Bacteria Bacteria, Aerobic Biological Models Emulsions Enterobacteriaceae Fungus, Filamentous Lactobacillus Lactococcus Milk, Cow's Peptones Sterility, Reproductive Technique, Dilution tellurite Yeasts
4
Optimizing Silage Production with Microbial Consortia
Materials used in the trial were sourced from experimental fields (containing 5 plots, 35 m2 per plot) at Nanjing Agriculture University (Jiangsu, China). The fields were at 32.04°N and 118.88°E, with an altitude of 25 m, and were located in a humid subtropical climate. Sweet sorghum, which was grown for ensiling, was harvested from 3 random plots at the dough stage on 28 August 2020, leaving a stubble of 10 cm. The harvested crops were wilted for 8 h and then cut into segments of 2 to 3 cm. The fresh sweet sorghum contained dry matter (DM) content of 229.26 g per each kg in fresh weight (FW), and its pH was measured to be 5.64. In every kilogram of DM were 90.77 g of water-soluble carbohydrates, 639.92 g of neutral detergent fiber, 331.25 g acid detergent fiber, and 54.11 g acid detergent lignin. Also, the epiphytic aerobic bacteria, yeasts, and lactic acid bacteria were at concentrations of 7.76, 6.53, and 5.81 log CFU g−1 FW, respectively.
Two cellulolytic microbial consortia applied in this study, CF (GenBank accession number SAMN16991296) and PY (GenBank accession number SAMN16807469), were both stored at −80°C before the experiment. Following procedures by Li et al. (18 (link)), they were cultured in LB media for ~36 to 48 h (optical density at 600 nm [OD600] of approximately 0.8) for activation. Dominant genera in CF were Enterococcus (14.9%), Klebsiella (8.5%), Escherichia (8.2%), Clostridium (3.46%), Lactobacillus (0.52%), Enterobacter (0.11%), Bacillus (0.02%), and Lactococcus (0.01%) (Table S1). In PY, the most notable genera were Klebsiella (29.8%), Enterococcus (19.0%), Escherichia (3.7%), Lysinibacillus (0.6%), Lactobacillus (0.40%), Bacteroides (0.38%), Streptococcus (0.15%), Cellulosilyticum (0.08%), and Bacillus (0.02%) (Table S1) (18 (link)). Consortia CF and PY are known to secrete various carbohydrate-active enzyme (CAZyme) families. In particular, PY holds up to 242 CAZyme-encoding genes, almost twice as many as bacteria from CF (n = 141). Most of these genes were glycosyl hydrolases (GHs), largely from the families GH1, GH3, and GH23, and known for their cellulolytic functions. Additionally, the study used a combination of lactic acid bacteria inoculants, specifically, Lactobacillus plantarum, Lactobacillus buchneri, and Pediococcus pentosaceus. To maintain a consistent composition of lactic acid bacteria and ensure the same number of cells were included in each species, individual strains were first prepared individually to the density of OD0.8. Then, equal proportions (1.0 mL) of each strain were mixed together.
Zhu Y.X., Zhang X., Yang W.C, & Li J.F. (2023). Enhancement of Biomass Conservation and Bioethanol Production of Sweet Sorghum Silage by Constructing Synergistic Microbial Consortia. Microbiology Spectrum, 11(1), e03659-22.
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Publication 2023
Acids Agricultural Crops Bacteria Bacteria, Aerobic Bacteroides Carbohydrates Climate Clostridium Culture Media Detergents Enterobacter Enterococcus Enzymes Epiphyses Escherichia Fibrosis Genes Hydrolase Klebsiella Lacticaseibacillus casei Lactobacillales Lactobacillus Lactobacillus buchneri Lactobacillus plantarum Lactococcus Lignin Microbial Consortia Pediococcus pentosaceus Sorghum Strains Streptococcus Yeasts
5
Phage Adsorption to Lactococcal Cells
Adsorption of phage to host cells was performed as described (Madera et al., 2003 (link)). Phage c2 was added at a MOI of 0.001 to stationary-phase host cultures diluted to an OD600 of 0.8 in GM17 supplemented with 10 mM of Ca(NO3)2 and 10 mM MgSO4. Following a 10 min incubation at room temperature, the phage-host mixture was centrifuged for 5 min, and phage counts in the supernatant determined by standard double-layer agar assays. A sample without cells was equally treated to determine the initial phage titer. The percentage adsorption was calculated as (1-residual phage titer/initial phage titer) × 100. Experiments were carried out with two to five independent lactococcal cultures.
Escobedo S., Pérez de Pipaon M., Rendueles C., Rodríguez A, & Martínez B. (2023). Cell wall modifications that alter the exolytic activity of lactococcal phage endolysins have little impact on phage growth. Frontiers in Microbiology, 14, 1106049.
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Publication 2023
Adsorption Agar Bacteriophages Biological Assay Cells Lactococcus Sulfate, Magnesium

Top products related to «Lactococcus»

1
M17 broth by Thermo Fisher Scientific
Sourced in United Kingdom, Italy, Denmark, United States, Spain
M17 broth is a microbiological culture medium used for the growth and propagation of lactic acid bacteria. It provides the necessary nutrients and growth factors to support the cultivation of these organisms in a laboratory setting.
2
M17 agar by Merck Group
Sourced in Germany, United Kingdom, United States, Poland
M17 agar is a culture medium used for the growth and isolation of lactic acid bacteria. It is a nutritionally rich medium that supports the growth of a variety of Gram-positive and Gram-negative bacteria. The medium contains lactose, peptones, and yeast extract, providing essential nutrients for bacterial growth.
3
Mrs agar by Merck Group
Sourced in Germany, United States, Italy, United Kingdom, Hungary, Poland
MRS agar is a laboratory culture medium used for the selective isolation and enumeration of lactic acid bacteria. It is designed to support the growth of organisms such as Lactobacillus, Pediococcus, and Leuconostoc species. MRS agar provides the necessary nutrients and growth factors required by these microorganisms.
4
M17 medium by Merck Group
Sourced in Germany, United States
M17 medium is a microbiological culture medium used for the isolation and cultivation of streptococcus species. It provides the necessary nutrients and growth factors to support the growth of these bacteria.
5
Mrs broth by Thermo Fisher Scientific
Sourced in United Kingdom, Italy, United States, Australia, Spain, Canada, Sweden, Belgium, Norway, Germany
MRS broth is a microbiological medium used for the selective isolation and cultivation of lactobacilli. It provides the necessary nutrients and growth factors for the optimal growth of lactobacilli species. The composition of the broth includes various peptones, yeast extract, glucose, and specific salts.
6
Erythromycin by Merck Group
Sourced in United States, Germany, France, United Kingdom, Italy, Sao Tome and Principe, Australia, China, Switzerland, Spain, Japan, Belgium, Macao
Erythromycin is a macrolide antibiotic produced by the bacterium Saccharopolyspora erythraea. It functions as a protein synthesis inhibitor by binding to the 50S subunit of the bacterial ribosome, preventing the translocation of the peptidyl-tRNA from the A-site to the P-site during translation.
7
Gene pulser xcell electroporation system by Bio-Rad
Sourced in United States, Japan, Germany
The Gene Pulser Xcell Electroporation System is a laboratory instrument designed for the delivery of nucleic acids, such as DNA or RNA, into cells through the process of electroporation. The system provides precise control over the electroporation parameters, allowing users to optimize the efficiency of gene transfer.
8
M17 agar by Solabia
Sourced in France
M17 agar is a microbiological growth medium used for the cultivation and enumeration of lactic acid bacteria. It provides the necessary nutrients and growth factors to support the growth of these organisms. The formulation is designed to promote the growth of streptococcal species.
9
Gp2 microplate by Biolog
Sourced in United States
The GP2 MicroPlate™ is a laboratory equipment designed for the identification and characterization of microorganisms. It provides a standardized system for testing the metabolic activity of various microbial strains. The GP2 MicroPlate™ contains a series of dehydrated substrates that allow for the assessment of carbon source utilization patterns, which can be used to differentiate between microbial species and subspecies.
10
M17 agar by Thermo Fisher Scientific
Sourced in United Kingdom, Germany, Denmark
M17 agar is a nutrient-rich medium used for the cultivation and enumeration of lactic acid bacteria, particularly streptococci. It provides the necessary nutrients and growth factors for the optimal growth of these microorganisms. The medium is formulated to support the specific nutritional requirements of lactic acid bacteria, making it a reliable and widely used tool in microbiology laboratories.

More about "Lactococcus"

Lactococcus, a genus of lactic acid bacteria, is a crucial component in the production of fermented dairy products such as cheese and yogurt.
These Gram-positive, catalase-negative, non-spore-forming, coccus-shaped microbes are commonly found in dairy items and the human gastrointestinal tract.
Through their ability to convert lactose into lactic acid, Lactococcus species play a vital role in the fermentation process.
Researchers studying Lactococcus can optimize their work using the AI-driven platform PubCompare.ai.
This innovative tool helps locate the best protocols from literature, preprints, and patents, enhancing the reproducibility and accuracy of Lactococcus research.
PubCompare.ai's intelligent analysis capabilities can greatly improve the efficiency and effectiveness of Lactococcus-related studies.
When cultivating Lactococcus, researchers often utilize M17 broth, M17 agar, and MRS agar.
These media provide the necessary nutrients and growth conditions for these lactic acid bacteria.
Additionally, the use of the M17 medium and MRS broth can be beneficial for various Lactococcus-related experiments.
Erythromycin, a macrolide antibiotic, has been used in Lactococcus research, particularly in studies involving genetic manipulation and transformation.
The Gene Pulser Xcell Electroporation System is a common tool employed for electroporation-mediated DNA transfer in Lactococcus species.
Furthermore, the GP2 MicroPlate™ can be utilized in high-throughput screening and analysis of Lactococcus cultures, allowing researchers to efficiently evaluate various growth conditions, metabolic activities, and other characteristics of these bacteria.
By incorporating these insights and tools, researchers can optimize their Lactococcus studies, leading to a deeper understanding of this important genus of lactic acid bacteria and its applications in the food and probiotic industries.