Here we report the genome sequence of the honeybee Apis mellifera, a key model for social behaviour and essential to global ecology through pollination. Compared with other sequenced insect genomes, the A. mellifera genome has high A+T and CpG contents, lacks major transposon families, evolves more slowly, and is more similar to vertebrates for circadian rhythm, RNA interference and DNA methylation genes, among others. Furthermore, A. mellifera has fewer genes for innate immunity, detoxification enzymes, cuticle-forming proteins and gustatory receptors, more genes for odorant receptors, and novel genes for nectar and pollen utilization, consistent with its ecology and social organization. Compared to Drosophila, genes in early developmental pathways differ in Apis, whereas similarities exist for functions that differ markedly, such as sex determination, brain function and behaviour. Population genetics suggests a novel African origin for the species A. mellifera and insights into whether Africanized bees spread throughout the New World via hybridization or displacement.
Neuropeptides, critical brain peptides that modulate animal behavior by affecting the activity of almost every neuronal circuit, are inherently difficult to predict directly from a nascent genome sequence because of extensive posttranslational processing. The combination of bioinformatics and proteomics allows unprecedented neuropeptide discovery from an unannotated genome. Within the Apis mellifera genome, we have inferred more than 200 neuropeptides and have confirmed the sequences of 100 peptides. This study lays the groundwork for future molecular studies of Apis neuropeptides with the identification of 36 genes, 33 of which were previously unreported.
Neuropeptides regulate most, if not all, biological processes in the animal kingdom, but only seven have been isolated and sequenced from Drosophila melanogaster. In analogy with the proteomics technology, where all proteins expressed in a cell or tissue are analyzed, the peptidomics approach aims at the simultaneous identification of the whole peptidome of a cell or tissue, i.e. all expressed peptides with their posttranslational modifications. Using nanoscale liquid chromatography combined with tandem mass spectrometry and data base mining, we analyzed the peptidome of the larval Drosophila central nervous system at the amino acid sequence level. We were able to provide biochemical evidence for the presence of 28 neuropeptides using an extract of only 50 larval Drosophila central nervous systems. Eighteen of these peptides are encoded in previously cloned or annotated precursor genes, although not all of them were predicted correctly. Eleven of these peptides were never purified before. Eight other peptides are entirely novel and are encoded in five different, not yet annotated genes. This neuropeptide expression profiling study also opens perspectives for other eukaryotic model systems, for which genome projects are completed or in progress.The most common approach in proteomic studies is to separate and visualize as many proteins as possible of an organism, tissue, or cell, by two-dimensional electrophoresis and to subsequently identify differentially expressed proteins by mass spectrometric techniques. One of the major constraints of this technology is that proteins of a molecular mass lower than 10 kDa are generally not retained and overlooked in most of the proteomic studies. Nevertheless this mass region contains a group of very important proteins, the peptide hormones and neurotransmitters.To date, many neuropeptides have been purified from vertebrate and invertebrate sources. Peptide physiology in the pregenomic era (before the realization of the genome projects) was time-consuming as a peptide present in tissue extracts had to be purified to homogeneity prior to sequencing, synthesis, and functional analysis.Drosophila is an outstanding model system for the molecular genetics and developmental biology in higher eukaryotes. Yet, its molecular endocrinology is poorly documented because only seven neuropeptides have been identified by traditional purification. Recently, a milestone was reached with the completion of the Drosophila genome project (1). Through the BLAST program, one can screen the genome of an organism for candidate-neuropeptides based on sequence homology with known neuropeptides from other organisms. In this way, 31 (neuro)peptide genes were found in Drosophila melanogaster (2-5). These findings, however, give no information on the temporal and spatial expression nor on the physiological relevance of these (neuro)peptide genes. Often, the precursors of biologically active peptides encode several peptides. In general, these peptides can be predicted from the precursor gene as it is assume...
In response to crowding, locusts develop characteristic black patterns that are well discernible in the gregarious phase at outbreaks. We report here a dark-colorinducing neuropeptide (dark-pigmentotropin) from the corpora cardiaca of two plague locusts, Schistocerca gregaria and Locusta migratoria. The chromatographic isolation of this neuropeptide was monitored by using a bioassay with an albino mutant of L. migratoria. Body-color polymorphism is widespread among animals. Two locust species, Schistocerca gregaria and Locusta migratoria, display conspicuous differences in body color, particularly during the nymphal stage. A major extrinsic factor influencing locust body color is phase polymorphism, a term used to describe continuous polymorphism in response to population density: locusts at a low density (solitary phase) are often green or brown, whereas those at outbreaks (gregarious phase) develop black patterns (1-4). Although the role of juvenile hormone in the induction of the green color is well established (2-4), little information is available about the hormonal factor that induces dark color in locusts. It has long been known that some factor present in the brain and the corp cardiaca (CC) promotes darkening in locusts (2, 3), but progress in identifying its chemical nature has been hampered by the lack of a convenient bioassay.Recently, we discovered an albino mutant, originating from a laboratory colony of an Okinawa (Japan) strain of L. migratoria (5). Albinism in this mutant is controlled by a single recessive Mendelian unite (5), as described also for other albino mutants of this species (6, 7), as well as of S. gregaria (8) and the grasshopper Melanoplus sanguinipes (under the name Melanoplus bilituratus) (9). The albinism in the Okinawa strain of L. migratoria is caused by the deficiency of a peptide(s) present in the central nervous system and the CC. Implantation of a brain or CC taken from normal (pigmented) individuals or injection of their methanolic extract induces dark color in albino locusts (10-12), but injection of such methanolic extract made from albino individuals has no dark-colorinducing effect in albino locusts (11). Of interest, implantation of brains or CC taken from other taxa, including S. gregaria and other acridids, cockroaches, katydids, crickets, and moths also are effective in inducing dark color in albino L. migratoria (10,12,13). This result indicates that similar substances inducing dark color in L. migratoria may exist in diverse groups of insects. Because whitish albino locusts can be obtained easily by mass rearing, they provide an excellent bioassay system for the characterization of this dark-color inducing peptide. Its role in body color polymorphism and phase polymorphism in locusts can then be determined by means of the synthetic analog. MATERIALS AND METHODSInsects and Tissue Extraction. The colony of the desert locust S. gregaria was maintained according to Ashby's method (14) and that of the migratory locust L. migratoria migratorioides as described...
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