Affiliation:
1. Microbiology Division, Food Laboratory, U.S. Army Natick Laboratories, Natick, Massachusetts 01760
Abstract
Spores of
Clostridium botulinum
type 62A were germinated in a chemically defined medium (8 m
m l
-cysteine, 11.9 m
m
sodium bicarbonate, 4.4 m
m
sodium thioglycolate; buffered with 100 m
m
TES,
p
H 7.0). The rate and extent of germination were increased when an aqueous spore suspension was heated sublethally (80 C, 60 min) before addition to the germination medium. Neither sublethal nor lethal doses of gamma radiation had any marked effect on subsequent germination. Maximum germination (>90% in 2 hr) in the defined medium occurred in the
p
H range of 6.5 to 7.5, at 30 to 37 C, with an
l
-cysteine level of 8 m
m
. Increasing
l
-cysteine to 32 m
m
increased the rate (over that with 8 m
m l
-cysteine) but not the extent of germination. The rate and extent of germination increased with NaHCO
3
addition to 8.3 m
m
, but increasing levels to 11.9 m
m
had no further effect. For maximum germination, 2.2 m
m
sodium thioglycolate was required and higher levels (to 8.8 m
m
) had no further enhancing or inhibitory effect. Under optimal conditions for germination, 97% of the spores had become heat sensitive; 98% had become sensitive to radiation; 88 and 91% had become phase dark and stainable, respectively, and the spore suspension had lost 46% of its initial optical density by 2 hr. Loss of heat resistance preceded loss of radiation resistance, acquisition of stainability, and phase darkening by about 12 min.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Reference23 articles.
1. Radiation sterilization of prototype military foods. II. Cured ham;Anellis A.;Appl. Microbiol.,1967
2. Spore germination in Clostridfum tyrobutyricum. I. Action of various compounds on the initial stage;Berg J. L.;Ann. Inst. Pasteur,1969
3. Adaptation of biphasic culture technique to the sporulation of Clostrfdlum botulinum type E;Bruch M. K.;J. Food Sci.,1967
4. Fermentative activities of control and radiation-"killed;Costilow R. N.;J. Bacteriol.,1962
5. Heat activation inducing germination in the spores of thermotolerant and therrophilic aerobic bacteria;Curran H. R.;J. Bacteriol.,1945
Cited by
54 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献