Changes in dopamine-sensitive adenylate cyclase activity in salivary glands of female lone star ticks, Amblyomma americanum (L.), during feeding

{ "0" : "Department of Entomology Oklahoma State University, Stillwater, OK 74078, U.S.A." , "1" : "Statistics Oklahoma State University, Stillwater, OK 74078, U.S.A." , "2" : "Biochemistry, Oklahoma State University, Stillwater, OK 74078, U.S.A." , "4" : "Cyclic nucleotides" , "5" : "adenylate cyclase" , "6" : "salivary glands" , "7" : "ticks" , "8" : "feeding" , "9" : "host effects"}
Insect Biochemistry 01/1984; 14(5):595-600. DOI: 10.1016/0020-1790(84)90016-7

ABSTRACT 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.

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    • "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). "
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    ABSTRACT: Salivary glands of female Amblyomma americanum (L.) are stimulated to differentiate by attachment to a host, subsequent feeding and mating. Incorporation of [3H]uridine into ribosomal and transfer RNAs as well as the synthesis of poly(A+)mRNA and protein parallel the pattern of increasing enzymatic activity and secretory ability of the glands. Unfed ticks contained 3.5 ± 0.47 ng poly(A+)mRNA/gland pr. By the second day of feeding this had increased more than 5-fold. The greatest amount of poly(A+)mRNA found in rapid-feeding phase females (body wt > 100 mg) was 370 ± 80 ng/gland pr. Poly(A+)mRNA mass doubles on the final day of feeding, just as the ticks exceeded 100 mg in wt. Ticks attached 1 to 10 days had increasingly greater amounts of salivary monosomes, 60 and 40S ribosomal subunits, and polysomes. Polysomal mass/gland pr also attained its maximum above 100 mg tick wt at the slow/rapid-feeding phase boundary; exceeding by 20 times that of unfed ticks. Degenerating glands from replete ticks continued to synthesize protein. In vitro incorporation of [3H]leucine was greatest within 24 h of attachment. Fluorographs of [3H]leucine labeled protein showed that mating caused a drop in incorporation after the 4th day of feeding. Glands from unmated females attached the same number of days continued to incorporate [3H]leucine at higher levels than those from mated females.
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