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In locusts, little is known about the physiological and biochemical mechanisms regulating complex processes, such as reproduction and phase transition. The pacifastin family constitutes a family of peptidic inhibitors of serine proteases that are considered to be important regulators of several physiological processes in arthropods. We have performed a detailed transcript profiling analysis of two pacifastin-related peptide precursors, SGPP-2 and SGPP-4, during the reproductive cycle of adult desert locusts ( Schistocerca gregaria). This quantitative real-time (RT)-PCR analysis revealed a temporal regulation of both transcripts, which is paralleled by several events that occur during the reproductive cycle of adult locusts. The observed temporal transcript profiles display a strong tissue-, gender- and phase-dependence. In addition, a partial regregarization experiment suggests that both transcript levels are regulated during phase transition and can be employed as molecular markers of the gregarization process. [ABSTRACT FROM AUTHOR]

In different parts of the world, locust swarms cause severe ecological and economic damage. However, the physiological mechanisms underlying this gregarization process remain elusive. In this study, we present a detailed quantitative analysis of two neuroparsin precursor ( Scg-NPP1 and Scg-NPP2) transcripts in the brain, fat body, gut, gonads and accessory glands of male and female, gregarious and solitarious desert locusts ( Schistocerca gregaria). These transcripts are generally more abundant in solitarious than in gregarious animals. In contrast to their gregarious congeners, solitarious locusts contain detectable Scg-NPP1 and Scg-NPP2 transcript levels in the fat body. Moreover, our data reveal temporal changes of neuroparsin mRNA levels in the brains and fat bodies of adult isolated-reared locusts. This paper provides the first scientific evidence for phase-dependent transcriptional regulation of neuropeptide hormone encoding genes. [ABSTRACT FROM AUTHOR]

This review summarizes recent advances and novel concepts in the area of insect reproductive neuroendocrinology. The role of ‘classic’ hormones, such as ecdysteroids and juvenoids, to control reproduction is well documented in a large variety of insect species. In adult gonads, ecdysteroids appear to induce a cascade of transcription factors, many of which also occur during the larval molting response. Recent molecular and functional data have created opportunities to study an additional level of regulation, that of neuropeptides, growth factors and their respective receptors. As a result, many homologs of factors playing a role in vertebrate reproductive physiology have been discovered in insects. This review highlights several neuropeptides controlling the biosynthesis and release of the ‘classic’ insect hormones, as well as various peptides and biogenic amines that regulate behavioural aspects of the reproduction process. In addition, hormone metabolizing enzymes and second messenger pathways are discussed with respect to their role in reproductive tissues. Finally, we speculate on future prospects for insect neuroendocrinological research as a consequence of the recent ‘Genomics Revolution’. [ABSTRACT FROM AUTHOR]

Abstract This study describes the identification and distribution of two novel neuroparsin precursor transcripts (Scg-NPP3 /Scg-NPP4 ) in the desert locust, Schistocerca gregaria . Unlike Scg-NPP1 and Scg-NPP2 , both transcripts were not only detected in the brain, but also in various other tissues, such as fat body, ventral nerve cord, testis and male accessory glands. Northern analysis showed that the levels of these transcripts are regulated during larval development, as well as during moulting and reproductive cycles. A significant increase in both mRNAs was observed during the period that just precedes the initial sexual activity of adult females and males. In silico analysis of sequence databases revealed the existence of several other neuroparsin-like peptides in a variety of arthropod species, including crustaceans and chelicerates. Neuroparsins also display similarities with vertebrate IGFBP. [ABSTRACT FROM AUTHOR]

Abstract A novel serine protease inhibitor peptide family, designated as the ‘pacifastin family’, has recently been described in insects (locusts, lepidopterans) and crustaceans (crayfish). This study presents the cDNA cloning of two isoforms of SGPP-3, a novel pacifastin-related precursor in the desert locust, Schistocerca gregaria , which codes for three putative inhibitor peptides. The precursor isoforms differ at a single amino acid position in the third, C-terminal peptide. Northern blot analysis confirmed the presence of two different transcripts (0.75 and 0.90 kb). Both transcripts are most abundant in the fat body and appear to be strongly regulated during the moulting cycle. In addition, the amount of transcript proved to be strictly regulated in the ovaries during the female reproductive cycle. [ABSTRACT FROM AUTHOR]

Abstract Recently, a novel serine protease-inhibiting peptide family, designated as the ‘pacifastin family’, has been described in locusts and crayfish. All members of this family possess a characteristic cysteine-rich domain. The present study describes the cDNA cloning, sequencing and transcript distribution of two novel pacifastin-related peptide precursors in the migratory locust, Locusta migratoria . Only one of the encoded peptides (HI) was identified previously, whereas six others represent new members of the pacifastin family. Northern blot analysis showed that both precursor transcripts are present in adult locust fat body. These could not be detected in the midgut. Interestingly, an in silico data mining approach of the expressed sequence tags (EST) database revealed the existence of Manduca sexta and Bombyx mori cDNAs that display pronounced sequence similarities with these locust pacifastin-related transcripts. [ABSTRACT FROM AUTHOR]

AbstractNeuroparsins were originally identified in locust corpus cardiacum extracts as folliculostatic or ‘antigonadotropic’ neuropeptides. This paper presents the cloning of two different neuroparsin precursor cDNAs from the brain of the desert locust, Schistocerca gregaria. The first transcript encodes the precursor (Scg-NPP1) of S. gregaria neuroparsin A and B, whereas the second codes for a novel neuroparsin-related peptide precursor (Scg-NPP2). Both precursors display significant sequence similarities with each other and with the Locusta migratoria neuroparsin (Lom-NPP) and Aedes aegypti ovary ecdysteroidogenic hormone (Aea-OEH1) precursors. Northern blot analysis revealed that these neuroparsin transcripts are present in larval and adult locust brains. Interestingly, the Scg-NPP2 mRNA content proved to be strongly regulated during the reproductive cycle in both adult males and females. [ABSTRACT FROM AUTHOR]