BACKGROUND The implementation of novel chassis organisms to be used as microbial cell factories in industrial applications is an intensive research field. Lactococcus lactis, which is one of the most extensively studied model organisms, exhibits superior ability to be used as engineered host for fermentation of desirable products. However, few studies have reported about genome reduction of L. ...

Lactococcus lactis is an immunomodulator and candidate live mucosal delivery vehicle for vaccine antigens and for biologically active molecules, including immunoregulatory cytokines such as interferon-gamma (IFN-gamma). To provide a tool for investigating downregulation of allergic predisposition of pigs to experimental food allergy, porcine IFN-gamma was cloned and expressed as a fusion protei...

A recombinant Streptococcus lactis strain which carries the structural gene for a surface protein antigen (PAc) of 190,000 daltons from Streptococcus mutans serotype c was constructed for development of an oral vaccine against dental caries. The gene from S. mutans MT8148 joined to shuttle vector pSA3 was successfully transformed into S. lactis IL1403. A small amount of PAc was detected in the ...

AIMS The aim of this study was to modulate the lactococcal proteolytic system for enhancement of the cheese ripening process. METHODS AND RESULTS The genes encoding PepN, PepC, PepX and PepI peptidases of a highly proteolytic Lactobacillus helveticus strain were transferred into Lactococcus lactis in a food-grade cloning system. A comparison of the relative peptidase activities from the trans...

The potential advantages of hyaluronic acid (HA) production by metabolically-engineered Lactococcus lactis is constrained by the lower molecular weight and yield of HA obtained in these strains, compared to natural producers. Earlier studies have correlated lower HA yield with excessive lactate production in L. lactis cultures (Chauhan et al., 2014). In the present study, a three-fold increase ...

OBJECTIVE To construct four recombinant Lactococcus lactis strains exhibiting high beta-galactosidase activity in fusion or non-fusion ways, and to study the influence factors for their protein expression and secretion. METHODS The gene fragments encoding beta-galactosidase from two strains of Lactobacillus bulgaricus, wch9901 isolated from yogurt and 1.1480 purchased from the Chinese Academy...

Post-weaning diarrhea (PWD) and edema disease (ED), caused by enterotoxigenic Shiga toxin producing Escherichia coli (ETEC STEC) strains, are important diseases of newly weaned piglets worldwide. The objective this study is to develop a passive immunization strategy protect against PWD ED using recombinant Lactococcus lactis added piglet diet at weaning. Variable Heavy chain domains antibodies ...

The conversion of pyruvate to lactate is a key feature of lactococcal strains. The enzyme which facilitates this conversion, L-lactate dehydrogenase (LDH), and the gene which encodes it (Idh), are therefore of great significance. This paper presents the cloning and DNA sequence analysis of three further lactococcal genes which are of key importance in the genetic manipulation of commercial star...

Fragments of Lactococcus lactis subsp. lactis NP45 chromosomal DNA provided promoter activity in Escherichia coli when cloned into the promoter probe vector pGKV210. Only 13% of these recombinant plasmids promoted detectable cat-86 activity when transferred to L. lactis, i.e., expressed chloramphenicol resistance. In these promoter-containing versions of pGKV210, the cat-86 gene specifies chlor...

The methods currently employed to produce recombinant Streptococcus gordonii strains for use as vaccines and/or protein expression vectors result in the insertion of foreign genes into an unknown integration site with no information on the transcriptional context or potential phenotypic consequences. Therefore, the genomic organization surrounding the insertion site of a recombinant strain of S...