The present disclosure provides recombinant Staphylococcus bacterium (e.g. S. epidermidis) that are dependent on D-alanine for growth. In one aspect, the disclosure features a recombinant Staphylococcus bacterium comprising two inactivated alanine racemase genes (alr1alr2); and an inactivated D-alanine aminotransferase (dat) gene. In another aspect, the disclosure features a method of making the recombinant Staphylococcus bacterium.

The present invention provides Listeria vaccine strains that express a heterologous antigen and a metabolic enzyme, and methods of generating same.

The present invention provides Listeria vaccine strains that express a heterologous antigen and a metabolic enzyme, and methods of generating same.

This invention relates generally to enzymes, polynucleotides encoding the enzymes, the use of such polynucleotides and polypeptides and more specifically to enzymes having transferase activity, e.g., transaminase activity, e.g., d-amino-acid transferase activity, and/or oxidoreductase activity, e.g., dehydrogenase activity, e.g., d-amino-acid dehydrogenase activity, and/or catalyze the transfer of a chemical group, catalyze transamination, catalyze the reaction: D-alanine+2-oxoglutarate<=>pyruvate+D-glutamate, and/or catalyze an oxidation-reduction reaction, catalyze the removal of hydrogen atoms, and/or catalyze the reaction: D-amino acid+H.sub.2O+acceptor<=>a 2-oxo acid+NH.sub.3+reduced acceptor.

Provided are methods for producing polysaccharides in bacteria by expressing in a bacterium one or more coding sequences selected from the group consisting of a pglF dehydrogenase coding sequence, a wbpP UDP-N-acetyl-d-glucosamine C4 epimerase coding sequence, a wcfR aminotransferase coding sequence, and a wcfS phospho-glycosyltransferase coding sequence, a wcfQ glycosyltransferase coding sequence, a wcfO pyruvyltransferase coding sequence, a wcfP glycosyltransferase coding sequence, a wcfM UDP-galactopyranose mutase coding sequence, a wcfN glycosyltransferase coding sequence, a wza polysaccharide export protein coding sequence, a wzx fippase coding sequence, a wzy polymerase coding sequence, and a wzz coding sequence, wherein at least one of the coding sequences is heterologous to the bacterium. Also provided are expression cassettes with one or more of the disclosed coding sequences, recombinant bacteria that harbor one or more of the expression cassettes, and methods for producing immunogenic compositions using the polysaccharides produced by the recombinant bacteria.

A method for producing 2,4-dihydroxybutyrate (DHB) or L-threonine using a microbial metabolic pathway is disclosed, by expressing the metabolic pathway in a microbial production strain which was previously modified with respect to its natural wild type form by introducing at least one of the genes necessary for the expression of those enzymes used for the enzymatic conversions into the production strain.

The present disclosure provides recombinant Staphylococcus bacterium (e.g. S. epidermidis) that are dependent on D-alanine for growth. In one aspect, the disclosure features a recombinant Staphylococcus bacterium comprising two inactivated alanine racemase genes (alr1 alr2); and an inactivated D-alanine aminotransferase (dat) gene. In another aspect, the disclosure features a method of making the recombinant Staphylococcus bacterium. In another aspect, the disclosure features a method of treating or preventing a rash in a subject, comprising administering to the subject a population of the recombinant Staphylococcus bacterium of any one of the aspects or embodiments described herein, in an effective amount to treat or prevent the rash in the subject.