Lactococcus lactis
Environmental MicrobiologyNisI Maturation and Its Influence on Nisin Resistance in Lactococcus lactisNisin, a safe and natural antimicrobial peptide, has a long and impressive history as a food preservative and is also considered a novel candidate to alleviate the increasingly serious threat of antibiotic resistance. Nisin is produced by certain L. lactis strains. The nisin immunity protein NisI, a membrane-bound lipoprotein, is expressed by nisin producers to avoid...
Food Microbiology | SpotlightEditing of the Proteolytic System of Lactococcus lactis Increases Its Bioactive PotentialLactic acid bacteria (LAB) are very important for the production of safe and healthy human and animal fermented foods and feed and, increasingly more, in the functional food industry. The intracellular peptidomes of LAB are promising reservoirs of bioactive peptides. We show here that targeted genetic engineering of the peptide degradation pathway allows steering the composition of the peptide pool of the LAB...
Food Microbiology | SpotlightAnother Breaker of the Wall: the Biological Function of the Usp45 Protein of Lactococcus lactisThe cell wall, composed mainly of peptidoglycan, is key to maintaining the cell shape and protecting the cell from bursting. Peptidoglycan degradation by peptidoglycan hydrolysis and autolysins occurs during growth and cell division. Since peptidoglycan hydrolases are important for virulence, envelope integrity, and regulation of cell division, it is valuable to investigate their function and regulation. Notably, PcsB-like proteins such...
Biotechnology | SpotlightNisin M: a Bioengineered Nisin A Variant That Retains Full Induction Capacity but Has Significantly Reduced Antimicrobial ActivityThis study describes the generation of a nisin variant with superior characteristics for use in the NICE protein expression system. The variant, termed nisin M, retains an induction capacity comparable to that of wild-type nisin A but exhibits significantly reduced antimicrobial activity and can therefore be used at concentrations that are normally toxic to the expression host.
Genetics and Molecular Biologyd-Methionine and d-Phenylalanine Improve Lactococcus lactis F44 Acid Resistance and Nisin Yield by Governing Cell Wall RemodelingAs d-amino acids play an important role in cell wall synthesis, we analyzed the effects of 19 different d-amino acids on L. lactis F44, demonstrating that d-Met and d-Phe can participate in peptidoglycan (PG) synthesis and improve the acid resistance and nisin yield of this...
Genetics and Molecular BiologyLysis of a Lactococcus lactis Dipeptidase Mutant and Rescue by Mutation in the Pleiotropic Regulator CodYPrecise control of peptidoglycan synthesis is essential in Gram-positive bacteria for maintaining cell shape and integrity as well as resisting stresses. Although neither the dipeptidase PepV nor alanine is essential for L. lactis MG1363, adequate availability of either ensures proper cell wall synthesis. We broaden the knowledge about the dipeptidase PepV, which acts...
Genetics and Molecular BiologyA Specific Sugar Moiety in the Lactococcus lactis Cell Wall Pellicle Is Required for Infection by CHPC971, a Member of the Rare 1706 Phage SpeciesGathering information on how lactococcal bacteriophages recognize their host and proliferate in the dairy environment is of vital importance for the establishment of proper starter culture rotation plans and to avoid fermentation failure and consequent great economic losses for dairy industries. We provide strong evidence on the type of receptor recognized by a newly isolated 1706-type lactococcal bacteriophage, increasing knowledge of...
Environmental Microbiology | SpotlightLanI-Mediated Lantibiotic Immunity in Bacillus subtilis: Functional AnalysisThe two lantibiotics nisin and subtilin are produced by Lactococcus lactis and Bacillus subtilis, respectively. Both peptides have strong antimicrobial activity against Gram-positive bacteria, and therefore, appropriate protection mechanisms are required for the producing strains. To prevent...
- Food Microbiology | SpotlightTask Distribution between Acetate and Acetoin Pathways To Prolong Growth in Lactococcus lactis under Respiration Conditions
Lactococcus lactis is used in food and biotechnology industries for its capacity to produce lactic acid, aroma, and proteins. This species grows by fermentation or by an aerobic respiration metabolism when heme is added. Whereas fermentation leads mostly to lactic acid production, respiration produces acetate and acetoin. Respiration growth leads to greatly improved...
- Genetics and Molecular BiologyVersatile Cas9-Driven Subpopulation Selection Toolbox for Lactococcus lactis