The marine vibrio ANT-500 is a typical psychrophile. The
growth range of the bacterium at 35��� S is from a maximum growth
temperature of 13.5 C to a minimum growth temperature of -2.5 C
or less with the optimum near 7 C. The bacterium elaborates its
chitinase enzymes between the temperatures of 1.5 and 13.5 C. The
enzyme system is composed of three separate enzymes, probably two
chitinases and one chitobiase. The rate limiting step of the enzyme-substrate
reaction appears to follow Mechaelis-Menton kinetics.
Chitin is the only substrate that induces chitinase synthesis in ANT-500.
Chitinase activity was found in the digestive tracts of all species
of fish sampled in Yaquina Bay, Oregon. Direct correlations were
noted between gut content and chitinase activity in the gut, gut content
and percent chitinoclasts in the gut, and chitinase activity and percent
chitinoclasts. Fish with little or no chitinous material in their gut
contents showed low or no detectable levels no chitinase activity and
a low percentage of chitinoclasts, while fish with predominantly
chitinous material in their gut contents showed high chitinase activity
and a large percentage of chitinoclasts. Neither hydrostatic pressure
up to 1000 atm nor lack of oxygen had a detrimental effect on chitinase
activity from the gut of Raja binoculata.
Sterile stomach fluid from Enophrys bison had no effect upon
the growth rates of a pure chitinoclastic and a mixed culture of
bacteria isolated from the gut of Enophrys bison; however, the gut
fluid did allow for greater cell yield. N-acetyl-D-glucosamine, the
end product of chitin decomposition, exhibited a ttglucose effect when
added to culture medium. Both the pure and the mixed culture showed
repression of growth in early log phase when grown in N-acetyl-D-glucosamine.
The chitinase isolated from the gut of Enophrys bison is bacterial
in origin. Tests in which the bacterial flora of the gut of Enophrys
bison was eliminated by use of chloramphenicol revealed no detectable
chitinase activity and no chitinoclastic bacterial populations. Fish
in the absence of the antibiotic showed both significant chitinase
activity and predominating chitinoclast populations. Other data
strongly indicate that the chitinase in many species of marine fishes
may also be bacterial in origin. / Graduation date: 1976
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/32136 |
| Date | 17 December 1975 |
| Creators | Goodrich, Thomas Dale |
| Contributors | Morita, Richard Y. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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