Abstract: The present invention provides a process of extracting nucleic acid in a simple manner at a high efficiency with no use of any hazardous reagent from biological materials having required specific procedure for nucleic acid extraction, particularly from biological materials such as bacteria of the genus Mycobacterium; and a process of simultaneously carrying out the extraction and purification of nucleic acid in a simple manner from such biological materials existing in a biological sample such as feces having involved much difficulty in the purification of the nucleic acid. In the present invention, vigorous agitation of biological materials with fine particles in solutions containing chelating reagents or agitation of biological materials with aqueous solutions containing chelating reagents and quaternary ammonium salts, together with organic solvents and fine particles is performed.

Abstract: The present invention relates to a peptide represented by the amino acid sequence of SEQ ID NO: 1, an antibacterial agent comprising the peptide as an active ingredient, a peptide gene encoding the peptide, a recombinant DNA comprising the peptide gene and a method for producing a peptide.The peptide of the present invention exhibits an effective antibacterial activity against various Gram-negative and -positive bacteria including Staphylococcus aureus and Bacillus cereus which are pathogenic bacteria causing food poisoning. Therefore, this peptide is useful as a food preservative and an antibacterial agent for medical use.