Abstract: A bacteriocin is obtained by culturing cells of a strain of Micrococcus varians which, upon culturing in a culture medium, produces a bacteriocin which has agar well incubation inhibition test activity against at least one of Lactobacillus, Lactococcus, Streptococcus, Enterococcus, Listeria, Bacillus, Clostridia and Straphylococcus bacteria. The strain is cultured to obtain cultured cells in a concentration of from 107 to 1011 organisms per ml of the medium, and the culture medium supernatant is separated from the cultured cells to obtain the supernatant which contains the bacteriocin, which is also identified by having an amino acid sequence from SEQ ID NO: 1 or a sequence differing from SEQ ID NO: 1 by from 1 to 4 amino acids.

Abstract: A method for treating or preventing mastitis in mammals is disclosed. The method contemplates the intramammary injection or dipping the teat with micrococcin antibiotics, preferably micrococcin P1 or P2, which do not interfere with the production of cheese and yoghurt using milk from treated animals. Hydrophobic antibiotics such as micrococcin P1 or P2 can be administered prior to infection to effectively suppress the rate, severity, and duration of subsequent bacterial infection, or can be administered subsequent to infection to effectively treat mastitis.

Abstract: An isolated peptide which in a microorganism, and particularly in Micrococcus varians, is a signal peptide which initiates expression of a bactericide composition.

Abstract: A method for treating or preventing mastitis in cows is disclosed. The method contemplates the intramammary injection or dipping the teat with Gallidermin and/or Epidermin or one of their pharmaceutically acceptable acid salts. Gallidermin and/or Epidermin or one of their pharmaceutically acceptable acid salts can be administered prior to infection to effectively suppress the rate, severity, and duration of subsequent bacterial infection, or can be administered subsequent to infection to effectively treat mastitis.

Abstract: The invention relates to the field of genetic engineering and provides novel DNA molecules which comprise multifunctional origins of replication and/or a DNA sequence coding for the most abundant protein in the supernatant of cultures of Lactococcus Spec., named Major Secretion Product (MSP), for its signal peptide and/or the promoter of the MSP gene. The novel DNA molecules are used for the production of novel shuttle vectors for cloning of DNA in at least E. coli and Lactococcus spec. or novel vectors for the expression of homologous or heterologous genes and the production of secreted gene products in gram positive bacteria such as Lactococcus spec. and Bacillus Spec.