Prostaglandin E 2 -stimulated secretion of protein in the salivary glands of the lone star tick via a phosphoinositide signaling pathway

Abstract Previous studies identified a prostaglandin E 2 (PGE 2 ) receptor in the salivary glands of partially fed female lone star ticks, Amblyomma americanum (L.). In the present studies, protein secretion from dispersed salivary gland acini was shown to be specific for PGE 2 , as compared with PGF 2α or the thromboxane analog U-46619, in accordance with their respective binding affinities for the PGE 2 receptor. Furthermore, the selective PGE 2 EP1 receptor agonist, 17-phenyl trinor PGE 2 , was as effective as PGE 2 in stimulating secretion of anticoagulant protein. Calcium ionophore A-23187 (1 to 100 µM) stimulated secretion of anticoagulant protein in a dose-dependent manner but the voltage-gated Ca 2+ -channel blocker verapamil (1 to 1000 µM) and the receptor-mediated Ca 2+ -entry antagonist, SK&F 96365 (1 and 10 µM), and 5 mM ethylene glycol bis(β-aminoethyl ether)-N,NNЈ,NЈ-tetraacetic acid (EGTA) had no appreciable effect on inhibiting PGE 2 -stimulated secretion of anticoagulant protein. PGE 2 (0.1 µM) and the nonhydrolyzable analog of guanosine triphosphate (GTP), GTPγS (10 µM), directly activated phospholipase C (PLC) in a membraneenriched fraction of the salivary glands after PLC was first incubated with the PGE 2 EP1 receptor antagonist AH-6809, which presumably antagonized endogenous PGE 2 (0.3 µM) in the broken-cell-membrane-enriched fraction. TMB-8, an antagonist of intracellular inositol trisphosphate (IP 3 ) receptors, inhibited PGE 2 -stimulated secretion. The results support the hypothesis that PGE 2 stimulates secretion of tick salivary gland protein via a phosphoinositide signaling pathway and mobilization of intracellular Ca 2+

Deciphering Proteomic Signatures of Early Diapause in Nasonia

Insect diapause is an alternative life-history strategy used to increase longevity and survival in harsh environmental conditions. Even though some aspects of diapause are well investigated, broader scale studies that elucidate the global metabolic adjustments required for this remarkable trait, are rare. In order to better understand the metabolic changes during early insect diapause, we used a shotgun proteomics approach on early diapausing and non-diapausing larvae of the recently sequenced hymenopteran model organism Nasonia vitripennis. Our results deliver insights into the molecular underpinnings of diapause in Nasonia and corroborate previously reported diapause-associated features for invertebrates, such as a diapause-dependent abundance change for heat shock and storage proteins. Furthermore, we observed a diapause-dependent switch in enzymes involved in glycerol synthesis and a vastly changed capacity for protein synthesis and degradation. The abundance of structural proteins and proteins involved in protein synthesis decreased with increasing diapause duration, while the abundance of proteins likely involved in diapause maintenance (e.g. ferritins) increased. Only few potentially diapause-specific proteins were identified suggesting that diapause in Nasonia relies to a large extent on a modulation of pre-existing pathways. Studying a diapause syndrome on a proteomic level rather than isolated pathways or physiological networks, has proven to be an efficient and successful avenue to understand molecular mechanisms involved in diapause

Sylvatic infestation of Oklahoma reptiles with immature Ixodes scapularis (Acari: Ixodidae)

Reptiles were collected in nine counties in Oklahoma from September 2002 to May 2004 and examined for Ixodes scapularis (Say) larvae and nymphs to determine seasonal incidence and prevalence of these ticks. In total, 209 reptile specimens consisting of nine species of lizards and seven species of snakes were collected. Plestiodon fasciatus (L.) was the most numerous species collected (55%) followed by Sceloporus undulatus (Latreille) (17%) and Scincella lateralis (Say) (11%). Less than 10 individuals were collected for all remaining reptile species. The infestation prevalence of I. scapularis on all reptile specimens collected was 14% for larvae and 25% for nymphs. Larvae were found on lizards from April until September and peaked in May, while nymphs were found from March until September and peaked in April. I. scapularis larvae (84%) and nymphs (73%) preferentially attached to the axillae/front leg of P. fasciatus. Two chigger species, Eutrombicula splendens (Ewing) and Eutrombicula cinnabaris (Ewing), were found on 2% of the reptiles collected. No ectoparasites, including ticks, were obtained from the seven species of snakes collected.Peer reviewedEntomology and Plant Patholog