Effect of short neuropeptide F signaling on larval feeding in Mythimna separata

Mythimna separata is a notorious phytophagous pest which poses serious threats to cereal crops owing to the gluttony of the larvae.Because short neuropeptide F(sNPF)and its receptor sNPFR are involved in a diversity of physiological functions,especially in functions related to feeding in insects,it is a molecular target for pest control.Herein,an sNPF and 2 sNPFRs were identified and cloned from M.separata.Bioinformatics analysis revealed that the sNPF and its receptors had a highly conserved RLRFamide C-terminus and 7 transmembrane domains,respectively.The sNPF and its receptor genes were distributed across larval periods and tissues,but 2 receptors had distinct expression patterns.The starvation-induced assay elucidated that sNPF and sNPFR expression levels were downregulated under food deprivation and recovered with subsequent re-feeding.RNA interference knockdown of sNPF,sNPFR1,and sNPFR2 by injection of double-stranded RNA into larvae not only suppressed food consumption and increased body size and weight,but also led to decrease of glycogen and total lipid contents,and increase of trehalose compared with double-stranded green fluorescent protein injection.Furthermore,molecular docking was performed on the interaction mode between sNPFR protein and its ligand sNPF based on the 3-dimensional models constructed by AlphaFold;the results indicated that both receptors were presumably activated by the mature peptide sNPF-2.These results revealed that sNPF signaling played a considerably vital role in the feeding regulation of M.separata and represents a potential control target for this pest.

Short neuropeptide F in integrated insect physiology

The short neuropeptide F(sNPF)family of peptides is a multifunctional group of neurohormones involved in the regulation of various physiological processes in insects.They have been found in a broad spectrum of species,but the number of isoforms in the precursor molecule varies from one to four.The receptor for sNPF(sNPFR),which belongs to the G protein-coupled receptor family,has been characterized in various insect orders and was shown to be an ortholog of the mammalian prolactin-releasing peptide receptor(PrPR).The sNPF signaling pathway interacts with other neurohormones such as insulin-like peptides,SIFamide,and pigment-dispersing factors(PDFs)to regulate various processes.The main physiological function of sNPF seems to be involved in the regulation of feeding,but the observed effects are species-specific.sNPF is also connected with the regulation of foraging behavior and the olfactory system.The influence of sNPF on feeding and thus energy metabolism may also indirectly affect other vital processes,such as reproduction and development.In addition,these neurohormones are involved in the regulation of locomotor activity and circadian rhythm in insects.This review summarizes the current state of knowledge about the sNPF system in insects.

Neuroendocrine regulation of reproduction in fish-Mini review

This review highlights the recent developments regarding neuroendocrine mechanisms controlling teleost reproduction.In teleosts,the pituitary gland receives major neuronal innervations from Gnrh neurons as well as minor innervations from small population of neurons that will secrete neurotransmitters and/or neuropeptides.The diversity of Kiss/Kissr system in various teleost species and their actions in the context of HPG axis and reproduction has been extensively covered.In teleost model systems,zebrafish and medaka,mutant lines for key components of the HPG axis have been generated through targeted mutagenesis but surprisingly most of the mutants developed normally without major defects in reproduction;these mutant phenotypes are described.In the last decade,complex role of diverse neuropeptides in teleost reproduction is being revealed.A brief overview about the reproductive functions of neuropeptides is presented.Finally,the effects of environmental factors namely photoperiodism and temperature on the functions of HPG axis is summarised.