Control of high-speed jumps: the rotation and energetics of the locust (Schistocerca gregaria)
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ABSTRACT:
ORGANISM(S): Schistocerca gregaria
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PROVIDER: S-BSST1003 | biostudies-other |
REPOSITORIES: biostudies-other
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Project description:Background: At the time of publication, the most devastating desert locust crisis in decades is affecting East Africa, the Arabian Peninsula and South-West Asia. The situation is extremely alarming in East Africa, where Kenya, Ethiopia and Somalia face an unprecedented threat to food security and livelihoods. Most of the time, however, locusts do not occur in swarms, but live as relatively harmless solitary insects. The phenotypically distinct solitarious and gregarious locust phases differ markedly in many aspects of behaviour, physiology and morphology, making them an excellent model to study how environmental factors shape behaviour and development. A better understanding of the extreme phenotypic plasticity in desert locusts will offer new, more environmentally sustainable ways of fighting devastating swarms. Methods: High molecular weight DNA derived from two adult males was used for Mate Pair and Paired End Illumina sequencing and PacBio sequencing. A reliable reference genome of Schistocerca gregaria was assembled using the ABySS pipeline, scaffolding was improved using LINKS. Results: In total, 1,316 Gb Illumina reads and 112 Gb PacBio reads were produced and assembled. The resulting draft genome consists of 8,817,834,205 bp organised in 955,015 scaffolds with an N50 of 157,705 bp, making the desert locust genome the largest insect genome sequenced and assembled to date. In total, 18,815 protein-encoding genes are predicted in the desert locust genome, of which 13,646 (72.53%) obtained at least one functional assignment based on similarity to known proteins. Conclusions: The desert locust genome data will contribute greatly to studies of phenotypic plasticity, physiology, neurobiology, molecular ecology, evolutionary genetics and comparative genomics, and will promote the desert locust's use as a model system. The data will also facilitate the development of novel, more sustainable strategies for preventing or combating swarms of these infamous insects.
| S-EPMC7607483 | biostudies-literature
Project description:DNA methylation is a widely conserved epigenetic modification that is established and maintained by the cooperative activity of DNA methyltransferases. While the complement of DNA methyltransferase genes can vary substantially between animal species, whole-genome methylation analyses have suggested that major features of animal methylomes are widely conserved. We have now used genome-scale bisulfite sequencing to analyze the methylome of the desert locust, Schistocerca gregaria, which represents an economically important pest with a high degree of phenotypic plasticity. Interestingly, in this system, DNA methylation appears to be both established and maintained by Dnmt1 methyltransferases, which distinguishes locusts from most other known organisms. Our results indicate that the S. gregaria methylome shares preferential methylation of CpG dinucleotides and exons with other animal methylomes. In contrast to other invertebrates, however, overall methylation levels were substantially higher and a significant fraction of transposons was methylated. Additionally, genes were densely methylated in a pronounced bimodal pattern, suggesting a role for DNA methylation in the regulation of locust gene expression. Altogether, our results uncover a unique pattern of genome methylation in locusts and also suggest that animal methylomes may be more diverse than previously thought.
2013-05-03 | GSE41214 | GEO
Project description:We have purified to homogeneity two forms of a new serine protease inhibitor specific for elastase/chymotrypsin from the ovary gland of the desert locust Schistocerca gregaria. This protein, greglin, has 83 amino acid residues and bears putative phosphorylation sites. Amino acid sequence alignments revealed no homology with pacifastin insect inhibitors and only a distant relationship with Kazal-type inhibitors. This was confirmed by computer-based structural studies. The most closely related homologue is a putative gene product from Ciona intestinalis with which it shares 38% sequence homology. Greglin is a fast-acting and tight binding inhibitor of human neutrophil elastase (k(ass)=1.2x10(7) M(-1) x s(-1), K(i)=3.6 nM) and subtilisin. It also binds neutrophil cathepsin G, pancreatic elastase and chymotrypsin with a lower affinity (26 nM< or =K(i)< or =153 nM), but does not inhibit neutrophil protease 3 or pancreatic trypsin. The capacity of greglin to inhibit neutrophil elastase was not significantly affected by exposure to acetonitrile, high temperature (90 degrees C), low or high pH (2.5-11.0), N-chlorosuccinimide-mediated oxidation or the proteolytic enzymes trypsin, papain and pseudolysin from Pseudomonas aeruginosa. Greglin efficiently inhibits the neutrophil elastase activity of sputum supernatants from cystic fibrosis patients. Its biological function in the locust ovary gland is currently unknown, but its physicochemical properties suggest that it can be used as a template to design a new generation of highly resistant elastase inhibitors for treating inflammatory diseases.
| S-EPMC1698593 | biostudies-literature
Project description:The desert locust Schistocerca gregaria recognizes multiple chemical cues, which are received by olfactory sensory neurons housed in morphologically identifiable sensilla. The different sensillum types contain olfactory sensory neurons with different physiological specificities, i.e., they respond to different categories of chemical signals. The molecular basis for the sensilla-specific responsiveness of these cells is unknown, but probably based on the endogenous receptor repertoire. To explore this issue, attempts were made to elucidate whether distinct odorant receptors (ORs) may be expressed in a sensilla-specific manner. Analyzing more than 80 OR types concerning for a sensilla-specific expression revealed that the vast majority was found to be expressed in sensilla basiconica; whereas only three OR types were expressed in sensilla trichodea. Within a sensillum unit, even in the multicellular assembly of sensilla basiconica, many of the OR types were expressed in only a single cell, however, a few OR types were found to be expressed in a consortium of cells typically arranged in a cluster of 2-4 cells. The notion that the OR-specific cell clusters are successively formed in the course of development was confirmed by comparing the expression patterns in different nymph stages. The results of this study uncover some novel and unique features of locust olfactory system, which will contribute to unravel the complexity of locust olfaction.
| S-EPMC6714038 | biostudies-literature
Project description:DNA methylation is a widely conserved epigenetic modification that is established and maintained by the cooperative activity of DNA methyltransferases. While the complement of DNA methyltransferase genes can vary substantially between animal species, whole-genome methylation analyses have suggested that major features of animal methylomes are widely conserved. We have now used genome-scale bisulfite sequencing to analyze the methylome of the desert locust, Schistocerca gregaria, which represents an economically important pest with a high degree of phenotypic plasticity. Interestingly, in this system, DNA methylation appears to be both established and maintained by Dnmt1 methyltransferases, which distinguishes locusts from most other known organisms. Our results indicate that the S. gregaria methylome shares preferential methylation of CpG dinucleotides and exons with other animal methylomes. In contrast to other invertebrates, however, overall methylation levels were substantially higher and a significant fraction of transposons was methylated. Additionally, genes were densely methylated in a pronounced bimodal pattern, suggesting a role for DNA methylation in the regulation of locust gene expression. Altogether, our results uncover a unique pattern of genome methylation in locusts and also suggest that animal methylomes may be more diverse than previously thought. Whole exome methylation analysis of S. gregaria. Two samples were analyzed, one sample containing DNA from brain, one sample containing DNA from MTG. To date, there exists no sequenced genome of Schistocerca gregaria; thus, we could only map the data against an EST database (Locust2 EST project) representing the coding part of the genome.
2013-05-03 | E-GEOD-41214 | biostudies-arrayexpress
Project description:The locust genus Schistocerca (Stål) has a transatlantic disjunction, which has been controversial for more than a century. Among 50 species within the genus, only one species, the desert locust (S. gregaria Forskål), occurs in the Old World, and the rest occur in the New World. Earlier taxonomists suggested that the desert locust is a migrant from America, but this view was strongly challenged when a large swarm of the desert locust successfully crossed the Atlantic Ocean from West Africa to the West Indies in 1988. The currently accepted view, supported by this incident, is that the New World species are descendants of a gregaria-like ancestor, and the desert locust would be ancestral to the rest of the genus. However, there is surprisingly little evidence to support this view other than the 1988 swarm. I present the most comprehensive phylogenetic study that suggests that the desert locust originated from the New World, contrary to the accepted view. I also present a hypothesis about how the ancestral Schistocerca might have colonized the New World in the first place in light of phylogenetic relationships with other cyrtacanthacridine genera.
| S-EPMC1691763 | biostudies-literature
Project description:Tychoparthenogenesis, a form of asexual reproduction in which a small proportion of unfertilized eggs can hatch spontaneously, could be an intermediate evolutionary link in the transition from sexual to parthenogenetic reproduction. The lower fitness of tychoparthenogenetic offspring could be due to either developmental constraints or to inbreeding depression in more homozygous individuals. We tested the hypothesis that in populations where inbreeding depression has been purged, tychoparthenogenesis may be less costly. To assess this hypothesis, we compared the impact of inbreeding and parthenogenetic treatments on eight life-history traits (five measuring inbreeding depression and three measuring inbreeding avoidance) in four laboratory populations of the desert locust, Schistocerca gregaria, with contrasted demographic histories. Overall, we found no clear relationship between the population history (illustrated by the levels of genetic diversity or inbreeding) and inbreeding depression, or between inbreeding depression and parthenogenetic capacity. First, there was a general lack of inbreeding depression in every population, except in two populations for two traits. This pattern could not be explained by the purging of inbreeding load in the studied populations. Second, we observed large differences between populations in their capacity to reproduce through tychoparthenogenesis. Only the oldest laboratory population successfully produced parthenogenetic offspring. However, the level of inbreeding depression did not explain the differences in parthenogenetic success between all studied populations. Differences in development constraints may arise driven by random and selective processes between populations.
| S-EPMC5551105 | biostudies-literature
Project description:Whereas short neuropeptide F (sNPF) has already been reported to stimulate feeding behaviour in a variety of insect species, the opposite effect was observed in the desert locust. In the present study, we cloned a G protein-coupled receptor (GPCR) cDNA from the desert locust, Schistocerca gregaria. Cell-based functional analysis of this receptor indicated that it is activated by both known isoforms of Schgr-sNPF in a concentration dependent manner, with EC(50) values in the nanomolar range. This Schgr-sNPF receptor constitutes the first functionally characterized peptide GPCR in locusts. The in vivo effects of the sNPF signalling pathway on the regulation of feeding in locusts were further studied by knocking down the newly identified Schgr-sNPF receptor by means of RNA interference, as well as by means of peptide injection studies. While injection of sNPF caused an inhibitory effect on food uptake in the desert locust, knocking down the corresponding peptide receptor resulted in an increase of total food uptake when compared to control animals. This is the first comprehensive study in which a clearly negative correlation is described between the sNPF signalling pathway and feeding, prompting a reconsideration of the diverse roles of sNPFs in the physiology of insects.
| S-EPMC3537624 | biostudies-literature
Project description:Adipokinetic hormone (AKH) is one of the most important metabolic neuropeptides in insects, with actions similar to glucagon in vertebrates. AKH regulates carbohydrate and fat metabolism by mobilizing trehalose and diacylglycerol into circulation from glycogen and triacylglycerol stores, respectively, in the fat body. The short peptide (8 to 10 amino acids long) exerts its function by binding to a rhodopsin-like G protein-coupled receptor located in the cell membrane of the fat body. The AKH receptor (AKHR) is, thus, a potential target for the development of novel specific (peptide) mimetics to control pest insects, such as locusts, which are feared for their prolific breeding, swarm-forming behavior and voracious appetite. Previously, we proposed a model of the interaction between the three endogenous AKHs of the desert locust, Schistocerca gregaria, and the cognate AKHR (Jackson et al., Peer J. 7, e7514, 2019). In the current study we have performed in silico screening of two databases (NCI Open 2012 library and Zinc20) to identify compounds which may fit the endogenous Schgr-AKH-II binding site on the AKHR of S. gregaria. In all, 354 compounds were found to fit the binding site with glide scores < −8. Using the glide scores and binding energies, 7 docked compounds were selected for molecular dynamic simulation in a phosphatidylcholine membrane. Of these 7 compounds, 4 had binding energies which would allow them to compete with Schgr-AKH-II for the receptor binding site and so are proposed as agonistic ligand candidates. One of the ligands, ZINC000257251537, was tested in a homospecific in vivo biological assay and found to have significant antagonistic activity.
| S-EPMC8953258 | biostudies-literature
Project description:Odorant-binding proteins (OBPs) are essential molecular elements of the insect chemosensory system, which is composed of the antennae and the mouthpart palps (maxillary and labial). In this study, we have analysed the expression and the sensilla specificity of 14 OBP subtypes in the palps of the desert locust Schistocerca gregaria. The locust palps comprise only a low number of sensilla basiconica but a high number of sensilla chaetica. Employing a variety of approaches, we found that only a subset of the antennal OBP repertoire was expressed in both palp types. These OBPs were previously shown to be expressed either in sensilla basiconica or sensilla chaetica of the antennae. Comparing the expression pattern in the two chemosensory organs revealed similarities and differences; most remarkably, two OBP subtypes, OBP6 and OBP8, were found in both sensilla types on palps, whereas on the antennae they were solely expressed in one sensillum type. Together, the data indicate a differential, but partly overlapping, expression of OBPs in the two sensilla types of the palps. The differences in the expression pattern of OBP subtypes between antennae and palps might be indicative for distinct functions of the OBPs in the two chemosensory organs.
| S-EPMC7380039 | biostudies-literature