Characteristics of a New Strain of Bacillus popilliae Sporogenic In Vitro

Abstract

Conditions are described that led to the isolation of NRRL B-2309M, a strain of Bacillus popilliae which sporulates regularly in laboratory culture. Colonies grown on a medium formulated with yeast extract and the ingredients of Mueller-Hinton with phosphate, trehalose, and agar, produced 20% spores in 10 to 12 days. The quantity and kind of yeast extract determine the extent of sporulation, although there are other requirements for optimal growth and sporulation. Spore inocula free of viable vegetative cells are necessary to maintain sporogenicity since asporogenic substrains arise spontaneously on solid and in liquid media. One such substrain, NRRL B-2309N, is also asporogenic in larvae, but lethal, owing to vigorous vegetative growth. Strain B-2309M is infective when vegetative cells or spores are injected into Japanese beetle larvae but fewer spores are formed in vivo than when infections are caused by NRRL B-2309. The characteristics of four related strains of B. popilliae are tabulated.

Physiological Studies of an Oligosporogenous Strain of Bacillus popilliae1

“…There was, however, a secondary growth response after some apparent cell lysis. I incubated These observations correlate well with those of ,mples were Sharpe et al (22). They observed that the spores me medium in the colonies were found in a concentric ring i rates were near the outer edge of the colony surrounded by iuired for a vegetative cells and prespore forms in the outer at-resistant fringe.…”

“…We have never been able to achieve the frequency of spore formation by B. popilliae strain 2309M in vitro as reported by Sharpe et al (22).…”

“…Sharpe et 2s was haral. (22) observed that the presence of trehalose at lays of inculevels above 0.1 % greatly reduced the frequency before and of sporulation with B. popilliae. However, high were fewer populations of spores accumulate in the hemoin the un-lymph of the Japanese beetle larvae in the pres-105 in the ence of high levels of trehalose (17).…”

Comparison of Pulsed-Field Gel Electrophoresis DNA Fingerprints of Field Isolates of the Entomopathogen Bacillus popilliae

“…Subculturing of the organism during spore production or strain maintenance may introduce the opportunity for the accumulation of genetic changes. Phenotypic variants of NRRL B-2309 have arisen in the past (16,18), and it is possible that previously undetected genetic changes have accumulated in various laboratories.…”

Characteristics of the constituent substrains of Bacillus popilliae growing in batch and continuous cultures

“…Large-scale fermentative production of infective spores of Bacillus popilliae Dutky would supply a proven biological insecticide (3,14) to control the Japanese beetle, Popillia japonica Newman. Suitable vegetative proliferation of this entomopathogen has been reported (9), and methods for obtaining limited sporulation in liquid and on solid medium have been described (5,10,15). Nevertheless, a means to induce extensive sporulation of B. popilliae growing in laboratory media has evaded discovery.…”