Lepidoptera is amongst one of the four most speciose insect orders and ecologically very successful because of their ability to fly. Insect flight is always aerobic and exacts a high metabolic demand on the animal. A family of structurally related neuropeptides, generically referred to as adipokinetic hormones (AKHs), play a key role in triggering the release of readily utilizable fuel metabolites into the hemolymph from the storage forms in the fat body. We used mass spectrometry to elucidate AKH sequences from 34 species of Lepidoptera and searched the literature and publicly available databases to compile (in a phylogenetic context) a comprehensive list of all Lepidoptera sequences published/predicted from a total of 76 species. We then used the resulting set of 15 biochemically characterized AKHs in a physiological assay that measures lipid or carbohydrate mobilization in three different lepidopteran species to learn about the functional cross-activity (receptor-ligand interactions) amongst the different butterfly/moth families. Our results include novel peptide structures, demonstrate structural diversity, phylogenetic trends in peptide distribution and order-specificity of Lepidoptera AKHs. There is almost an equal occurrence of octa-, nona-, and decapeptides, with an unparalleled emphasis on nonapeptides than in any insect order. Primitive species make Peram-CAH-II, an octapeptide found also in other orders; the lepidopteran signature peptide is Manse-AKH. Not all of the 15 tested AKHs are active in Pieris brassicae; this provides insight into structure-activity specificity and could be useful for further investigations into possible biorational insecticide development.

• Keywords
• Lepidoptera, adipokinetic hormone, biological assays, butterflies and moths, mass spectrometry, neuropeptides, primary structure,
• Publication type
• Journal Article MeSH

Insect adipokinetic hormones (AKHs) are short peptides produced in the corpora cardiaca and are responsible for mobilizing energy stores from the fat body to the hemolymph. Three related peptides, AKH1, AKH2, and AKH/corazonin-related peptide (ACP) as well as three AKH receptors have been reported in Bombyx mori. AKH1 and AKH2 are specific for the AKHR1 receptor, whereas ACP interacts with the other two AKHRs. To assess the effect of the two silkworm AKHs and ACP in the regulation of energy homeostasis we examined the expression pattern of the three peptides and their receptors as well as their effect on the level of carbohydrates and lipids in the hemolymph. Our results support the hypothesis that only AKH1 and AKH2 peptides together with the AKHR1 receptor are involved in the maintenance of energy homeostasis. Because Bombyx AKHR1 (BmAKHR1) seems to be a true AKHR we generated its mutation. The BmAKHR1 mutant larvae display significantly lower carbohydrate and lipid levels in the hemolymph and reduced sensitivity to starvation. Our study clarifies the role of BmAKHR1 in energy homeostasis.

• Keywords
• BMSK0010951, Bommo-AKH1, Bommo-AKH2, NM_001043584, TALEN, silkworm, targeted mutagenesis,
• MeSH
• Bombyx growth & development   metabolism   MeSH
• Energy Metabolism MeSH
• Hemolymph metabolism   MeSH
• Insect Hormones genetics   metabolism   MeSH
• Insect Proteins genetics   metabolism   MeSH
• Pyrrolidonecarboxylic Acid analogs & derivatives   metabolism   MeSH
• Larva metabolism   MeSH
• Lipids analysis   MeSH
• Mutagenesis MeSH
• Neuropeptides genetics   metabolism   MeSH
• Oligopeptides genetics   metabolism   MeSH
• Protein Isoforms genetics   metabolism   MeSH
• Receptors, Glucagon genetics   metabolism   MeSH
• Gene Expression Regulation MeSH
• Carbohydrates analysis   MeSH
• Signal Transduction * MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• adipokinetic hormone MeSH Browser
• corazonin protein, insect MeSH Browser
• Insect Hormones MeSH
• Insect Proteins MeSH
• Pyrrolidonecarboxylic Acid MeSH
• Lipids MeSH
• Neuropeptides MeSH
• Oligopeptides MeSH
• Protein Isoforms MeSH
• Receptors, Glucagon MeSH
• Carbohydrates MeSH

EFLamide (EFLa) is a neuropeptide known for a long time from crustaceans, chelicerates and myriapods. Recently, EFLa-encoding genes were identified in the genomes of apterygote hexapods including basal insect species. In pterygote insects, however, evidence of EFLa was limited to partial sequences in the bed bug (Cimex), migratory locust and a few phasmid species. Here we present identification of a full length EFLa-encoding transcript in the linden bug, Pyrrhocoris apterus (Heteroptera). We created complete null mutants allowing unambiguous anatomical location of this peptide in the central nervous system. Only 2-3 EFLa-expressing cells are located very close to each other near to the surface of the lateral protocerebrum with dense neuronal arborization. Homozygous null EFLa mutants are fully viable and do not have any visible defect in development, reproduction, lifespan, diapause induction or circadian rhythmicity. Phylogenetic analysis revealed that EFLa-encoding transcripts are produced by alternative splicing of a gene that also produces Prohormone-4. However, this Proh-4/EFLa connection is found only in Hemiptera and Locusta, whereas EFLa-encoding transcripts in apterygote hexapods, chelicerates and crustaceans are clearly distinct from Proh-4 genes. The exact mechanism leading to the fused Proh-4/EFLa transcript is not yet determined, and might be a result of canonical cis-splicing, cis-splicing of adjacent genes (cis-SAG), or trans-splicing.

• Keywords
• Alternative splicing, CRISPR/Cas9, EFLamide, In silico peptide prediction, Null mutant, TRH,
• MeSH
• Phylogeny MeSH
• Heteroptera genetics   metabolism   MeSH
• Insect Proteins chemistry   genetics   metabolism   MeSH
• Thyrotropin-Releasing Hormone genetics   metabolism   MeSH
• Neuropeptides chemistry   genetics   metabolism   MeSH
• Amino Acid Sequence MeSH
• Sequence Alignment MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Insect Proteins MeSH
• Thyrotropin-Releasing Hormone MeSH
• Neuropeptides MeSH

Nineteen species of various families of the order Diptera and one species from the order Mecoptera are investigated with mass spectrometry for the presence and primary structure of putative adipokinetic hormones (AKHs). Additionally, the peptide structure of putative AKHs in other Diptera are deduced from data mining of publicly available genomic or transcriptomic data. The study aims to demonstrate the structural biodiversity of AKHs in this insect order and also possible evolutionary trends. Sequence analysis of AKHs is achieved by liquid chromatography coupled to mass spectrometry. The corpora cardiaca of almost all dipteran species contain AKH octapeptides, a decapeptide is an exception found only in one species. In general, the dipteran AKHs are order-specific- they are not found in any other insect order with two exceptions only. Four novel AKHs are revealed by mass spectrometry: two in the basal infraorder of Tipulomorpha and two in the brachyceran family Syrphidae. Data mining revealed another four novel AKHs: one in various species of the infraorder Culicumorpha, one in the brachyceran superfamily Asiloidea, one in the family Diopsidae and in a Drosophilidae species, and the last of the novel AKHs is found in yet another Drosophila. In general, there is quite a biodiversity in the lower Diptera, whereas the majority of the cyclorraphan Brachycera produce the octapeptide Phote-HrTH. A hypothetical molecular peptide evolution of dipteran AKHs is suggested to start with an ancestral AKH, such as Glomo-AKH, from which all other AKHs in Diptera to date can evolve via point mutation of one of the base triplets, with one exception.

• Keywords
• adipokinetic and hypertrahalosemic biological assays, adipokinetic peptides, diptera, fly phylogeny, mass spectrometry,
• MeSH
• Chromatography, Liquid MeSH
• Diptera chemistry   classification   genetics   metabolism   MeSH
• Mass Spectrometry MeSH
• Insect Hormones analysis   chemistry   genetics   metabolism   MeSH
• Pyrrolidonecarboxylic Acid analogs & derivatives   analysis   chemistry   metabolism   MeSH
• Evolution, Molecular * MeSH
• Oligopeptides analysis   chemistry   genetics   metabolism   MeSH
• Peptides analysis   chemistry   genetics   metabolism   MeSH
• Amino Acid Sequence MeSH
• Structure-Activity Relationship MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• adipokinetic hormone MeSH Browser
• Insect Hormones MeSH
• Pyrrolidonecarboxylic Acid MeSH
• Oligopeptides MeSH
• Peptides MeSH