Cell Walls of Pirigularia Oryzae

Abstract

Cell walls were prepared from Piricularia oryzae P2. Lytic enzymes were produced when Bacillus circulans WL 12 was grown with P. oryzae cell wall as a sole source of carbon. Mode of lysis of P. oryzae cell walls was compared with the lysis of walls of Aspergillus oryzae and Neurospora crassa. Activities of j3-1--~3-glucanase, chitinase, and (3-1->6-glucanase were demonstrated in the culture filtrate. Modes of lysis of cell walls of P. oryzae P2 by a single and combined action of lytic enzymes were compared. Combination of j3-1->3-glucanase and chitinase gave the most rapid and extensive lysis.Pathogenicity of Piricularia oryzae, a group of rice blast molds, has hitherto been studied in our laboratory primarily from the stand point of toxins, piricularin and picolinic acid, produced by the pathogens (1, 2).In order to expand the scope of our work on the host-parasite interactions, we recently started our work with cytological and biochemical approaches. Naturally, first contact between the host and the pathogen takes place at the surfaces of both organisms.We consider that the studies on the surface nature of P. oryzae and also of rice plants might give us some evidence which will help in our understanding of host-parasite interactions. Our understanding on the cell walls of fungi is still meager when compared with our knowledge on the walls of yeasts and bacteria.

Cell Walls of Regenerating Protoplasts ofPyricularia oryzaeP2

“…Pyricularia oryzae Pz was originally obtained from the National Institute of Agricultural Sciences, Tsukuba, Japan. Bacillus circulans WL 12 13 ) was used for the production of the lytic enzyme complex.…”

Expression inEscherichia coliof theBacillus circulansWL-12 Structural Gene for β-1,3-Glucanase A

“…All of the preculture was inoculated into 200 ml of L-broth containing ampicillin and incubated. At a certain incubation time, cells were collected by centrifugation, and the cytoplasmic and periplasmic fractions were prepared by the method of Tsukagoshi et aU 2 ) The method is based on the treatment with lysozyme-EDT A to form spheroplasts as described by Birdsell et alY) For the analysis of /3-1,3-glucanase by SDS-PAGE, E. coli cells were grown at 30°C for 24 hr and the periplasmic fraction was prepared by the cold osmotic shock procedure of Neu et al 14 ) Deletion analysis of recombinant plasmid. Sequential deletions were introduced into the inserted DNA region of the recombinant plasmid using a Deletion Kit purchased from Takara ShuZD Co., Ltd. (Kyoto, Japan) by the method described in the instruction manual.…”

Glycogen Granules in Regenerating Protoplasts ofPyricularia oryzaeP2

“…Serratia marcescens (IFO 12648) was obtained from the Institute for Fermentation, Osaka, Japan. Bacillus circulans WL12 3 ) was used for the production of lytic enzymes.…”