AN ANALYSIS OF PARASPORAL INCLUSIONS OF BACILLUS THURINGIENSIS SUBSPECIES FINITIMUS (CRYSTALS, SPORE)

LAJOYCE ANN HENDERSON DEBRO, Purdue University

Abstract

Bacillus thuringiensis subspecies finitimus produced at least two parasporal inclusions. One inclusion was formed within the exosporium and remained with the spore subsequent to mother cell lysis. A second inclusion formed somewhat later exterior to the exosporium. Each inclusion contained a major polypeptide of about 135 kd with unique antigenic determinants. This subspecies contained only two plasmids of 98 Md and 77 Md. Strains cured of these plasmids produced only the free inclusion. Since the plasmid-cured strains did not contain DNA sequences homologous to plasmid DNA, the gene for the free-inclusion protein must be encoded in the chromosome. In contrast, the enclosed parasporal inclusion was produced only when the plasmid of 98 Md was present. In addition, transfer of the 98 Md plasmid to B. cereus resulted in transcipients that produced small inclusions enclosed within the exosporium and the protein extracted from these inclusions reacted with antibody specific for enclosed-inclusion protein of subspecies finitimus. Genes in both the chromosome and a plasmid function in the synthesis of distinct parasporal proteins in this subspecies. The gene encoding the parasporal protein from the enclosed inclusion was cloned into E. coli by screening digests of the 98 Md plasmid with other protoxin gene clones. A 11.7 kbp PstI fragment produced a polypeptide of about 120 kd that reacted with antibody to parasporal inclusion protein of subspecies finitimus.

Degree

Ph.D.

Subject Area

Microbiology

COinS