The activity of dopamine-sensitive adenylate cyclase in feeding female ixodid tick salivary glands was dependent on the state of tick feeding. Activity was significantly greater than the “basal” activity in salivary glands from ticks at all stages of tick feeding. Enzyme activity was not detected in the glands of unfed females. Enzyme activity reached a peak in glands of ticks weighing approx. 200 mg then declined as ticks increased in weight beyond 200 mg to repletion. Replete ticks (detached from the host for 12–24 hr) had similar levels of basal and dopamine-stimulated adenylate cyclase activity as that measured in salivary glands of high weight (>200 mg) ticks. Enzyme activity was 19–62% less in glands from ticks feeding on hosts that had been parasitized 2–4 months earlier by lone star ticks.
"Various activities, such as salivary gland fluid secretory ability, are greatly stimulated after attachment, and reach a peak at the end of the slow phase of feeding (Sauer et al. 1989). Enzymes, such as dopamine-sensitive adenylyl cyclase (Schramke et al. 1984) and cAMP phosphodiesterase (McMullen et al. 1983) show a similar or inverse behavior. Both the overall protein composition and the mRNA content of the salivary gland change dramatically (McSwain et al. 1982; Shelby et al. 1987). "
[Show abstract][Hide abstract] ABSTRACT: A collection of EST clones from female tick Amblyomma americanum salivary glands was hybridized to RNA from different feeding stages of female tick salivary glands and from unfed or feeding adult male ticks. In the female ticks, the expression patterns changed dramatically upon starting feeding, then changed again towards the end of feeding. On beginning feeding, genes possibly involved in survival on the host increased in expression as did many housekeeping genes. As feeding progressed, some of the survival genes were downregulated, while others were upregulated. When the tick went into the rapid feeding phase, many of the survival genes were downregulated, while a number of transport-associated genes and genes possibly involved in organ degeneration increased. In the males, the presence of females during feeding made a small difference, but feeding made a larger difference. Males showed clear differences from females in expression, as well. Protein synthesis genes were expressed more in all male groups than in the partially fed females, while the putative secreted genes involved in avoiding host defenses were expressed less.
Archives of Insect Biochemistry and Physiology 08/2009; 71(4):236-53. DOI:10.1002/arch.20318 · 1.02 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Basal levels of cAMP in salivary glands of female lone star ticks were found to be about 5 pmoles/mg protein during all stages of feeding. Glands stimulated with 10(-5)M dopamine and 10(-5)M dopamine plus theophylline exhibited significant increases in cAMP/mg protein. After stimulation by 10(-5)M dopamine was removed, cAMP decreased faster in glands from slowly feeding ticks (less than 200 mg) than in glands of rapidly feeding ticks (greater than 200 mg).
Comparative Biochemistry and Physiology Part C Comparative Pharmacology and Toxicology 02/1984; 79(1):47-50. DOI:10.1016/0742-8413(84)90161-0
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