This study investigated some functional and
biochemical characteristics of a bacteriolytic protein in
the salivary glands of adult Aedes aecupti. A method for
the isolation of this protein from other mosquito salivary
gland components is also described. Based on some of its
biochemical properties, this bacteriolytic protein can be
classified as a lysozyme.
This protein is strongly-linked to mosquito
sugarfeeding activity because there is a statistically
significant (P < 0.05) increase in the levels of lytic
activity six hours before mosquitoes start to sugar feed.
By its bacteriolytic action, it may function as a
protective mechanism against bacteria-contaminated sugar
meals. Preliminary work suggests that mosquitoes exposed
to lyophilized Micrococcus lysodeikticus in their sugar
meal respond by increasing the lytic activity in their
salivary glands.
The levels of bacteriolytic activity are apparently
not affected by bloodfeeding. In the absence of feeding,
as in teneral and bloodfed mosquitoes, salivary
bacteriolytic activity increases to a maximum, then levels
off. This suggests a regulation of the synthesis of this
salivary protein that is independent of the feeding state
of the adult mosquito.
A combination of centrifugation, polyacrylamide gel
electrophoresis (non-denaturing and denaturing), cation
exchange chromatography and gel filtration, was used to
isolate the protein from other mosquito salivary gland
components. This salivary protein is lysozyme-like in
several aspects: 1) it lyses bacterial cell walls of M.
lysodeikticus, 2) it is a basic protein with a pI between
7.47 and 8.89, 3) it is thermostable at low pH, and loses
its activity at high pH, and 4) it is composed of one
polypeptide chain. Its molecular weight is twice that of
hen egg white lysozyme. This salivary bacteriolytic
protein is the first insect exocrine lysozyme to be
characterized. / Graduation date: 1992
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/36394 |
| Date | 16 August 1991 |
| Creators | Pimentel, Gliceria Estandian, 1958- |
| Contributors | Rossignol, Philippe A. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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