Journal of the Chemical Society, Chemical Communications, 1993
The absolute configuration of juvenile hormone Ill bisepoxide, the putative characteristic juveni... more The absolute configuration of juvenile hormone Ill bisepoxide, the putative characteristic juvenile hormone of higher dipteran insects, has been established as 2€,6S,7S,lOR by HPLC and cyclodextrin-modified CE comparison of synthetic stereoisomers with biosyntheticalty 3H-labelled hormone froen the Australian sheep blowfly Lucilia cuprina.
The distribution of neurones immunoreactire to antisera raised against the undecapeptide Ctermina... more The distribution of neurones immunoreactire to antisera raised against the undecapeptide Cterminal fragment of drosulfakinin II (DrmSKII), Asp-Gln-Phe-Asp-Asp-Tyr (SO 3H)-Gly-His-Met-Arg-Phe-NH2, has been studied in the blowfly Calliphora vomitoria. Antisera were preabsorbed with combinations of the parent antigen, the tetrapeptide Phe-Met-Arg-Phe-NH 2 and cholecystokinin, the vertebrate sulfated octapeptide (CCK-8), Asp-Tyr(SO3H)-Met-Gly-Trp-Met-Asp-Phe-NH2, in order to ensure specificity for the sulfakinin peptides of C. vomitoria (the nonapeptide callisulfakinin I is identical to drosulfakinin I and callisulfakinin II differs from DrmSK II only by the presence of-Glu3-Glu 4-in place of -Asp3-Asp4-). Only four pairs of sulfakinin-immunoreactive neurones have been visualised in the entire nervous system. These occur in the brain: two pairs of cells situated medially in the caudo-dorsal region close to the roots of the ocellar nerve and two other pairs at the same level but positioned more laterally. Despite the small number of sulfakinin-immunoreactive cells, there are extensive projections to many areas of neuropile in the brain and the thoracic ganglion. The pathway of the medial sulfakinin cells extends into each of the three thoracic ganglia and a metameric arrangement of sulfakinin neuronal projections is also seen in the abdominal ganglia. Neither the dorsal neural sheath of the thoracic ganglion, nor the abdominal nerves contain sulfakinin-immunoreactive material. These observations suggest that the sulfakinins of the blowfly function as neurotransmitters or neuromodulators. They do not appear to have a direct role in gut physiology, as has been shown by in vitro bioassays for the sulfakinins of orthopterans and blattodeans. In addition to the neurones that display specific sulfakinin immunoreactivity, other cells within the brain and thoracic ganglion are immunoreactive to cholecystokinin/gastrin antisera. There are, therefore, at least two types of dipteran neuropeptides with amino acid sequences that are similar to the vertebrate molecules cholecystokinin and gastrin.
Mature, mated female D. buzzatii were given a choice of nine microbial communities actively growi... more Mature, mated female D. buzzatii were given a choice of nine microbial communities actively growing on cactus homogenate in laboratory population cages, and tests were made to determine if flies of different genotypes (for seven allozyme loci) chose different microorganism species for either feeding or oviposition. Variation in feeding preferences was determined from assays of electrophoretic genotypes and the ingested microorganism species of individual flies. Oviposition preference variation was analysed indirectly by assaying the genotypes of individuals raised from eggs laid on different microorganisms. No significant evidence was found for differences in feeding preferences among adults of different genotypes. For oviposition preferences, there were significant microorganism-genotype associations for each of seven polymorphic loci. Analyses of the total electrophoretic genotype, rather than of individual loci, showed that the genotypes of eggs laid on the same microorganism species were more similar than those laid on different species. That is, females of different genotypes show habitat selection for oviposition sites, which would facilitate the maintenance of genetic polymorphisms.
Temporal variation in allozyme frequencies at six loci was studied by making monthly collections ... more Temporal variation in allozyme frequencies at six loci was studied by making monthly collections over 4 yr in one population of the cactophilic species Drosophila burratii. Ten sites were defined within the study locality, and for all temporal samples, separate collections were made at each of these sites. Population structure over microgeographic space and changes in population structure over time were analyzed using F-statistic estimators, and multivariate analyses of allele and genotype frequencies with environmental variables were carried out.-Allele frequencies showed significant variation over time, although there were no clear cyclical o r seasonal patterns. A biplot analysis of allele frequencies over seasons within years and over years showed clear discrimination among years by alleles at four loci. During the 4 yr. three alleles showed directional changes which were associated with directional changes in environmental variables. Significant associations with one or more environmental variables were found for allele frequencies at every locus and for both expected and observed heterozygosities (except those for Est-1 and Est-2). Thus, variation in allele frequencies over time cannot be attributed solely to drift. Significant linkage disequilibria were detected among three loci (Est-2, Hex and Aldox), but there was n o evidence for spatial or temporal patterns.-The F-statistic analyses showed significant differentiation among months within years for all loci, but the statistic used (coancestry) was heterogeneous among loci. Estimates of F (inbreeding) for all loci were significantly different from zero, with the loci in four groups, Adh-1 (negative), Pgm (small positive), Est-2 and Hex (intermediate) and Est-1 and Aldox (high positive). T h e correlation of genes within individuals within populations (f) for each locus in each month by site sample differed among loci, as did the patterns of change in f over time (seasons). Heterogeneity in the F-statistic estimates indicates that natural selection is directly or indirectly affecting allele and genotype frequencies at some loci. However, the F-statistic analyses showed essentially no microgeographic structure (i.e., among sites), although there was significant heterogeneity in allele frequencies among flies emerging from individual rots.-Thus, microspatial heterogeneity probably is most important at the level of individual rots, and coupled with habitat selection, it could be a major factor promoting diversifying selection and the maintenance of polymorphism. Resolution of the nature of this selection and of the apparent inbreeding detected at all loci except Adh-l will require detailed study of the breeding struc-' Present address:
A novel, hydroxyproline-containing neuropeptide, Gly-Pro-Hyp-Tyr-Asp-Phe-Gly-Met-NH2, designated ... more A novel, hydroxyproline-containing neuropeptide, Gly-Pro-Hyp-Tyr-Asp-Phe-Gly-Met-NH2, designated [HYP3]Met-callatostatin, has been identified from extracts of heads of the blowfly Calliphora vomitoria. The peptide is a naturally occurring hydroxylate analogue of Met-callatostatin, a previously identified allatostatin-like peptide, and is present to the extent of 20% of the nonhydroxylated form. In bioassays, both forms of the peptide show allatostatic activity by inhibiting juvenile hormone synthesis and release in the cockroaches Periplaneta americana, Diploptera punctata, and Blattella germanica (IC50 = 100 pM-10 nM). They do not, however, influence juvenile hormone bisepoxide synthesis and release in the blowfly. In flies, [Hyp3]Met-callatostatin inhibits the peristaltic movements of the hindgut, showing a biphasic response (IC50 = 0.5 pM and 0.5 microM) compared with the monophasic response of Met-callatostatin (IC50 = 100 nM). Immunocytochemical studies with Met-callatostatin antisera provide the cytological basis for a myoinhibitory role in the gut since the axons of immunoreactive neurons in the abdominal ganglion project to the ileum. There are also endocrine cells in the midgut that, by releasing the peptides into the hemolymph, would allow the Met-callatostatins to fulfill a neurohormonal role on muscles of the gut and heart. In contrast, there are no Met-callatostatin neural pathways from the brain to the corpus allatum, the gland that produces juvenile hormone. NH2-terminal degradation of Met-callatostatins incubated with the hemolymph of P. americana results in cleavage of the Pro-Tyr bond giving the pentapeptide Tyr-Asp-Phe-Gly-Met-NH2 as a degradation product. In contrast, the Hyp-Tyr bond resists cleavage. With hemolymph from C. vomitoria, no immunoassayable degradation product has been observed with either peptide.
In order to estimate migration and gene flow, allele frequencies in populations at two sites sepa... more In order to estimate migration and gene flow, allele frequencies in populations at two sites separated by 120 m were differentially perturbed by the continuous release over 413 days of flies homozygous at particular allozyme loci. The effects of perturbation were determined by genotype assay at two collections prior to, thirteen during and nine after the perturbation period. Maximum likelihood methods were developed to estimate migration into the two populations from the homozygous releases, and migration between the two populations. The successful perturbation of allele frequencies in a natural population is demonstrated. A plateau in allele frequencies during perturbation and a return to original frequencies following cessation of perturbation was most likely due to selection during development against recessive alleles concurrently introduced into the populations by the released flies. There is unequivocal evidence for short distance gene flow between the two populations. The mig...
ABSTRACT Drosophila buzzatii has two closely linked loci (0· 4 ± O· 3 cM apart) encoding NAD + -d... more ABSTRACT Drosophila buzzatii has two closely linked loci (0· 4 ± O· 3 cM apart) encoding NAD + -dependent alcohol dehydrogenase. These two loci produce complex, non-overlapping electrophoretic phenotypes and differ in their ontogenetic expression, that of Adh-l relative to Adh-2 being less in adults than in third-instar larvae. Isozymes produced by the two Adh-2 alleles analysed have similar in vitro ADH activity levels, substrate specificities and thermostabilities, whereas the isozymes of the two Adh-l alleles examined differ in ADH activity and specificity for primary versus secondary alcohol substrates.
Proceedings of the National Academy of Sciences of the United States of America, 2010
The recent assembly of the silkworm Bombyx mori genome with 432 Mb on 28 holocentric chromosomes ... more The recent assembly of the silkworm Bombyx mori genome with 432 Mb on 28 holocentric chromosomes has become a reference in the genomic analysis of the very diverse Order of Lepidoptera. We sequenced BACs from two major pests, the noctuid moths Helicoverpa armigera and Spodoptera frugiperda, corresponding to 15 regions distributed on 11 B. mori chromosomes, each BAC/region being anchored by known orthologous gene(s) to analyze syntenic relationships and genome rearrangements among the three species. Nearly 300 genes and numerous transposable elements were identified, with long interspersed nuclear elements and terminal inverted repeats the most abundant transposable element classes. There was a high degree of synteny conservation between B. mori and the two noctuid species. Conserved syntenic blocks of identified genes were very small, however, approximately 1.3 genes per block between B. mori and the two noctuid species and 2.0 genes per block between S. frugiperda and H. armigera. This corresponds to approximately two chromosome breaks per Mb DNA per My. This is a much higher evolution rate than among species of the Drosophila genus and may be related to the holocentric nature of the lepidopteran genomes. We report a large cluster of eight members of the aminopeptidase N gene family that we estimate to have been present since the Jurassic. In contrast, several clusters of cytochrome P450 genes showed multiple lineagespecific duplication events, in particular in the lepidopteran CYP9A subfamily. Our study highlights the value of the silkworm genome as a reference in lepidopteran comparative genomics.
We describe the distribution of sulfakinin-like neuropeptides in the central and sympathetic nerv... more We describe the distribution of sulfakinin-like neuropeptides in the central and sympathetic nervous system of the American cockroach Periplaneta americana (L.) (Blattodea) and the field cricket Teleogryllus commodus (Walker) (Orthoptera), using an antisulfakinin primary antibody and confocal laser scanning microscopy. We conclude that, in the cockroach, sulfakinin-like material is produced in ten pairs of anterior cells in the pars intercerebralis, as well as two pairs of medial and one major pair of lateral posterior brain cells. This contrasts with findings in other insects, including the cricket, where only the posterior cell groups express sulfakinin-immunoreactive material. Extensive arborization of dendrites containing sulfakinin-like peptides occurs within the neuropile of both species, suggesting a neurotransmitter/ neuromodulator function. In the cockroach, there is clear evidence of direct distribution of sulfakinin-like peptides along axons to the foregut tissue, and a plexus of retrocerebral nerves is likely to serve as a neurohaemal release site. Neurohaemal release into the dorsal aorta is also postulated. Sulfakininimmunoreactive axons do not innervate the hindgut in either cockroaches or crickets. Sulfakinin may function as a gut myotropin in the Blattodea, in addition to functioning as a neurotransmitter within the central nervous system. This latter function appears to be general across insect orders, while the neurohaemal distribution and myotropic activity are restricted to the Blattodea.
The nonapeptide, Phe-Asp-Asp-Tyr(SO3)-Gly-His-Met-Arg-Phe-NH2 was isolated from heads of the blow... more The nonapeptide, Phe-Asp-Asp-Tyr(SO3)-Gly-His-Met-Arg-Phe-NH2 was isolated from heads of the blowfly Calliphora vomitoria. Designated callisulfakinin I, the peptide is identical to the earlier known drosulfakinin I of Drosophila melanogaster and to neosulfakinin I of Neobellieria bullata. It belongs to the sulfakinin family, all known members of which (from flies, cockroaches and locusts) have the C-terminal heptapeptide sequence Asp-Tyr(SO3)-Gly-His-Met-Arg-Phe-NH2. The callisulfakinin gene of C. vomitoria was cloned and sequenced. In addition to callisulfakinin I, the DNA revealed a coding sequence for the putative tetradecapeptide. Gly-Gly-Glu-Glu-Gln-Phe-Asp-Asp-Tyr-Gly-His- Met-Arg-Phe-NH2, callisulfakinin II. However, this peptide was not identified in the fly head extracts. Confocal laser scanning immunocytochemical studies with antisera raised against the synthetic undecapeptide C-terminal fragment of drosulfakinin II from D. melanogaster, Asp-Gln-Phe-Asp-Asp-Tyr(SO3)- Gly-His-Met-Arg-Phe-NH2, revealed only four pairs of sulfakinin neurones in the brain of C. vomitoria and no others anywhere else in the neural, endocrine or gut tissues. In situ hybridisation studies with a digoxigenin-labelled sulfakinin gene probe (from the blowfly Lucilia cuprina) also revealed only four pairs of neurones in the brain. The perikarya of two pairs of cells are situated medially in the caudo-dorsal region, close to the roots of the ocellar nerve. The other perikarya are slightly more posterior and lateral. Although it has been suggested by several authors that the insect sulfakinins are homologous to the vertebrate peptides gastrin and cholecystokinin, such arguments (based essentially on C-terminal structural similarities) do not take account of important differences in the C-terminal tetrapeptide. His-Met-Arg-Phe-NH2 in the sulfakinins, compared with Trp-Met-Asp-Phe-NH2 in gastrin and cholecystokinin. Furthermore, whereas the sulfakinin neurons of C. vomitoria are small in number and have a very specialised location, a greater number of cells throughout the nervous system react positively to gastrin/cholecystokinin antisera. Chromatographic profiles of the present study also revealed peaks of gastrin/cholecystokinin-immunoreactive material separate from the sulfakinin peptides. This evidence suggests that the insect and vertebrate peptides may not necessarily be homologous.
The prohormonegene encodingthe Leu-callatostatinpeptideshas been isolatedfrom a Calliphora wmitor... more The prohormonegene encodingthe Leu-callatostatinpeptideshas been isolatedfrom a Calliphora wmitoria genomicDNA library and its homologuewas cloned from genomicand cDNA librariesof anotherblowflyspecies, Lucilia crqrinu. Gene and prohormone structure and organisationare essentially identical in the two species. The Leu-callatostatingene consists of at least 3 exons. The prohormoneis encodedon exonstwo and threeand the two blocksof putativeLeu-callatostatinpeptidesare carriedon separateexons.It is 180 amino-acidslong, begins with a short signal peptide and containstwo blocks of tandemlyarrangedLeu-callatostatinpeptides separatedby an acidic spacer region. The prohormonecontains 5 copies of the C-terminal sequence-YXFGL characteristicof the Leu-callatostatinfamily. Complete endoproteolyticprocessingat all possible pairs of basic amino acids would generate 5 different Leu-callatostatinoctapeptides.TwolargerLeu-callatostatins couldbe releasedif processingwas not completeat two of the sites.Noneof the 3 peptidesencodedin the first block was identifiedin previouspurificationstudiesof the callatostatinpeptides.The secondblock, locatedat the carboxylend of the prohormone, containstwopeptidesequencesidenticalto the previouslyisolatedLeu-callatostatins1 and 4. The absenceof independentcopies of Leu-callatostatins2 and 3 on the prohormoneestablishesthat endoproteolyticcleavageof the precursordoes not invariablyproceedto completionand that Leu-callatostatin2 must be derivedby N-terminalprocessingof the parent peptideLeu-callatostatin1. ReversetranscriptasePCR analysisof mRNAfrombrain and midgut,the two major sites of Leu-callatostatin expression,shows that the prohormonesequenceat these two sites is identical,ruling out the possibilitythat differentpopulationsof peptidesare expressedin these two tissues as a result of alternativeRNA splicing.
TARA D. SUTHERLAND's2 and PETER D. EAST' 'CSIRO,DivisionofEntomology, Canberra, Au... more TARA D. SUTHERLAND's2 and PETER D. EAST' 'CSIRO,DivisionofEntomology, Canberra, Australia, and ?Department of Entomology, University of Arizona, Tucson, Arizona, USA ... Abstract. Juvenile Hormone I11 bisepoxide synthesis by ring gland complexes from third-...
Journal of the Chemical Society, Chemical Communications, 1993
The absolute configuration of juvenile hormone Ill bisepoxide, the putative characteristic juveni... more The absolute configuration of juvenile hormone Ill bisepoxide, the putative characteristic juvenile hormone of higher dipteran insects, has been established as 2€,6S,7S,lOR by HPLC and cyclodextrin-modified CE comparison of synthetic stereoisomers with biosyntheticalty 3H-labelled hormone froen the Australian sheep blowfly Lucilia cuprina.
The distribution of neurones immunoreactire to antisera raised against the undecapeptide Ctermina... more The distribution of neurones immunoreactire to antisera raised against the undecapeptide Cterminal fragment of drosulfakinin II (DrmSKII), Asp-Gln-Phe-Asp-Asp-Tyr (SO 3H)-Gly-His-Met-Arg-Phe-NH2, has been studied in the blowfly Calliphora vomitoria. Antisera were preabsorbed with combinations of the parent antigen, the tetrapeptide Phe-Met-Arg-Phe-NH 2 and cholecystokinin, the vertebrate sulfated octapeptide (CCK-8), Asp-Tyr(SO3H)-Met-Gly-Trp-Met-Asp-Phe-NH2, in order to ensure specificity for the sulfakinin peptides of C. vomitoria (the nonapeptide callisulfakinin I is identical to drosulfakinin I and callisulfakinin II differs from DrmSK II only by the presence of-Glu3-Glu 4-in place of -Asp3-Asp4-). Only four pairs of sulfakinin-immunoreactive neurones have been visualised in the entire nervous system. These occur in the brain: two pairs of cells situated medially in the caudo-dorsal region close to the roots of the ocellar nerve and two other pairs at the same level but positioned more laterally. Despite the small number of sulfakinin-immunoreactive cells, there are extensive projections to many areas of neuropile in the brain and the thoracic ganglion. The pathway of the medial sulfakinin cells extends into each of the three thoracic ganglia and a metameric arrangement of sulfakinin neuronal projections is also seen in the abdominal ganglia. Neither the dorsal neural sheath of the thoracic ganglion, nor the abdominal nerves contain sulfakinin-immunoreactive material. These observations suggest that the sulfakinins of the blowfly function as neurotransmitters or neuromodulators. They do not appear to have a direct role in gut physiology, as has been shown by in vitro bioassays for the sulfakinins of orthopterans and blattodeans. In addition to the neurones that display specific sulfakinin immunoreactivity, other cells within the brain and thoracic ganglion are immunoreactive to cholecystokinin/gastrin antisera. There are, therefore, at least two types of dipteran neuropeptides with amino acid sequences that are similar to the vertebrate molecules cholecystokinin and gastrin.
Mature, mated female D. buzzatii were given a choice of nine microbial communities actively growi... more Mature, mated female D. buzzatii were given a choice of nine microbial communities actively growing on cactus homogenate in laboratory population cages, and tests were made to determine if flies of different genotypes (for seven allozyme loci) chose different microorganism species for either feeding or oviposition. Variation in feeding preferences was determined from assays of electrophoretic genotypes and the ingested microorganism species of individual flies. Oviposition preference variation was analysed indirectly by assaying the genotypes of individuals raised from eggs laid on different microorganisms. No significant evidence was found for differences in feeding preferences among adults of different genotypes. For oviposition preferences, there were significant microorganism-genotype associations for each of seven polymorphic loci. Analyses of the total electrophoretic genotype, rather than of individual loci, showed that the genotypes of eggs laid on the same microorganism species were more similar than those laid on different species. That is, females of different genotypes show habitat selection for oviposition sites, which would facilitate the maintenance of genetic polymorphisms.
Temporal variation in allozyme frequencies at six loci was studied by making monthly collections ... more Temporal variation in allozyme frequencies at six loci was studied by making monthly collections over 4 yr in one population of the cactophilic species Drosophila burratii. Ten sites were defined within the study locality, and for all temporal samples, separate collections were made at each of these sites. Population structure over microgeographic space and changes in population structure over time were analyzed using F-statistic estimators, and multivariate analyses of allele and genotype frequencies with environmental variables were carried out.-Allele frequencies showed significant variation over time, although there were no clear cyclical o r seasonal patterns. A biplot analysis of allele frequencies over seasons within years and over years showed clear discrimination among years by alleles at four loci. During the 4 yr. three alleles showed directional changes which were associated with directional changes in environmental variables. Significant associations with one or more environmental variables were found for allele frequencies at every locus and for both expected and observed heterozygosities (except those for Est-1 and Est-2). Thus, variation in allele frequencies over time cannot be attributed solely to drift. Significant linkage disequilibria were detected among three loci (Est-2, Hex and Aldox), but there was n o evidence for spatial or temporal patterns.-The F-statistic analyses showed significant differentiation among months within years for all loci, but the statistic used (coancestry) was heterogeneous among loci. Estimates of F (inbreeding) for all loci were significantly different from zero, with the loci in four groups, Adh-1 (negative), Pgm (small positive), Est-2 and Hex (intermediate) and Est-1 and Aldox (high positive). T h e correlation of genes within individuals within populations (f) for each locus in each month by site sample differed among loci, as did the patterns of change in f over time (seasons). Heterogeneity in the F-statistic estimates indicates that natural selection is directly or indirectly affecting allele and genotype frequencies at some loci. However, the F-statistic analyses showed essentially no microgeographic structure (i.e., among sites), although there was significant heterogeneity in allele frequencies among flies emerging from individual rots.-Thus, microspatial heterogeneity probably is most important at the level of individual rots, and coupled with habitat selection, it could be a major factor promoting diversifying selection and the maintenance of polymorphism. Resolution of the nature of this selection and of the apparent inbreeding detected at all loci except Adh-l will require detailed study of the breeding struc-' Present address:
A novel, hydroxyproline-containing neuropeptide, Gly-Pro-Hyp-Tyr-Asp-Phe-Gly-Met-NH2, designated ... more A novel, hydroxyproline-containing neuropeptide, Gly-Pro-Hyp-Tyr-Asp-Phe-Gly-Met-NH2, designated [HYP3]Met-callatostatin, has been identified from extracts of heads of the blowfly Calliphora vomitoria. The peptide is a naturally occurring hydroxylate analogue of Met-callatostatin, a previously identified allatostatin-like peptide, and is present to the extent of 20% of the nonhydroxylated form. In bioassays, both forms of the peptide show allatostatic activity by inhibiting juvenile hormone synthesis and release in the cockroaches Periplaneta americana, Diploptera punctata, and Blattella germanica (IC50 = 100 pM-10 nM). They do not, however, influence juvenile hormone bisepoxide synthesis and release in the blowfly. In flies, [Hyp3]Met-callatostatin inhibits the peristaltic movements of the hindgut, showing a biphasic response (IC50 = 0.5 pM and 0.5 microM) compared with the monophasic response of Met-callatostatin (IC50 = 100 nM). Immunocytochemical studies with Met-callatostatin antisera provide the cytological basis for a myoinhibitory role in the gut since the axons of immunoreactive neurons in the abdominal ganglion project to the ileum. There are also endocrine cells in the midgut that, by releasing the peptides into the hemolymph, would allow the Met-callatostatins to fulfill a neurohormonal role on muscles of the gut and heart. In contrast, there are no Met-callatostatin neural pathways from the brain to the corpus allatum, the gland that produces juvenile hormone. NH2-terminal degradation of Met-callatostatins incubated with the hemolymph of P. americana results in cleavage of the Pro-Tyr bond giving the pentapeptide Tyr-Asp-Phe-Gly-Met-NH2 as a degradation product. In contrast, the Hyp-Tyr bond resists cleavage. With hemolymph from C. vomitoria, no immunoassayable degradation product has been observed with either peptide.
In order to estimate migration and gene flow, allele frequencies in populations at two sites sepa... more In order to estimate migration and gene flow, allele frequencies in populations at two sites separated by 120 m were differentially perturbed by the continuous release over 413 days of flies homozygous at particular allozyme loci. The effects of perturbation were determined by genotype assay at two collections prior to, thirteen during and nine after the perturbation period. Maximum likelihood methods were developed to estimate migration into the two populations from the homozygous releases, and migration between the two populations. The successful perturbation of allele frequencies in a natural population is demonstrated. A plateau in allele frequencies during perturbation and a return to original frequencies following cessation of perturbation was most likely due to selection during development against recessive alleles concurrently introduced into the populations by the released flies. There is unequivocal evidence for short distance gene flow between the two populations. The mig...
ABSTRACT Drosophila buzzatii has two closely linked loci (0· 4 ± O· 3 cM apart) encoding NAD + -d... more ABSTRACT Drosophila buzzatii has two closely linked loci (0· 4 ± O· 3 cM apart) encoding NAD + -dependent alcohol dehydrogenase. These two loci produce complex, non-overlapping electrophoretic phenotypes and differ in their ontogenetic expression, that of Adh-l relative to Adh-2 being less in adults than in third-instar larvae. Isozymes produced by the two Adh-2 alleles analysed have similar in vitro ADH activity levels, substrate specificities and thermostabilities, whereas the isozymes of the two Adh-l alleles examined differ in ADH activity and specificity for primary versus secondary alcohol substrates.
Proceedings of the National Academy of Sciences of the United States of America, 2010
The recent assembly of the silkworm Bombyx mori genome with 432 Mb on 28 holocentric chromosomes ... more The recent assembly of the silkworm Bombyx mori genome with 432 Mb on 28 holocentric chromosomes has become a reference in the genomic analysis of the very diverse Order of Lepidoptera. We sequenced BACs from two major pests, the noctuid moths Helicoverpa armigera and Spodoptera frugiperda, corresponding to 15 regions distributed on 11 B. mori chromosomes, each BAC/region being anchored by known orthologous gene(s) to analyze syntenic relationships and genome rearrangements among the three species. Nearly 300 genes and numerous transposable elements were identified, with long interspersed nuclear elements and terminal inverted repeats the most abundant transposable element classes. There was a high degree of synteny conservation between B. mori and the two noctuid species. Conserved syntenic blocks of identified genes were very small, however, approximately 1.3 genes per block between B. mori and the two noctuid species and 2.0 genes per block between S. frugiperda and H. armigera. This corresponds to approximately two chromosome breaks per Mb DNA per My. This is a much higher evolution rate than among species of the Drosophila genus and may be related to the holocentric nature of the lepidopteran genomes. We report a large cluster of eight members of the aminopeptidase N gene family that we estimate to have been present since the Jurassic. In contrast, several clusters of cytochrome P450 genes showed multiple lineagespecific duplication events, in particular in the lepidopteran CYP9A subfamily. Our study highlights the value of the silkworm genome as a reference in lepidopteran comparative genomics.
We describe the distribution of sulfakinin-like neuropeptides in the central and sympathetic nerv... more We describe the distribution of sulfakinin-like neuropeptides in the central and sympathetic nervous system of the American cockroach Periplaneta americana (L.) (Blattodea) and the field cricket Teleogryllus commodus (Walker) (Orthoptera), using an antisulfakinin primary antibody and confocal laser scanning microscopy. We conclude that, in the cockroach, sulfakinin-like material is produced in ten pairs of anterior cells in the pars intercerebralis, as well as two pairs of medial and one major pair of lateral posterior brain cells. This contrasts with findings in other insects, including the cricket, where only the posterior cell groups express sulfakinin-immunoreactive material. Extensive arborization of dendrites containing sulfakinin-like peptides occurs within the neuropile of both species, suggesting a neurotransmitter/ neuromodulator function. In the cockroach, there is clear evidence of direct distribution of sulfakinin-like peptides along axons to the foregut tissue, and a plexus of retrocerebral nerves is likely to serve as a neurohaemal release site. Neurohaemal release into the dorsal aorta is also postulated. Sulfakininimmunoreactive axons do not innervate the hindgut in either cockroaches or crickets. Sulfakinin may function as a gut myotropin in the Blattodea, in addition to functioning as a neurotransmitter within the central nervous system. This latter function appears to be general across insect orders, while the neurohaemal distribution and myotropic activity are restricted to the Blattodea.
The nonapeptide, Phe-Asp-Asp-Tyr(SO3)-Gly-His-Met-Arg-Phe-NH2 was isolated from heads of the blow... more The nonapeptide, Phe-Asp-Asp-Tyr(SO3)-Gly-His-Met-Arg-Phe-NH2 was isolated from heads of the blowfly Calliphora vomitoria. Designated callisulfakinin I, the peptide is identical to the earlier known drosulfakinin I of Drosophila melanogaster and to neosulfakinin I of Neobellieria bullata. It belongs to the sulfakinin family, all known members of which (from flies, cockroaches and locusts) have the C-terminal heptapeptide sequence Asp-Tyr(SO3)-Gly-His-Met-Arg-Phe-NH2. The callisulfakinin gene of C. vomitoria was cloned and sequenced. In addition to callisulfakinin I, the DNA revealed a coding sequence for the putative tetradecapeptide. Gly-Gly-Glu-Glu-Gln-Phe-Asp-Asp-Tyr-Gly-His- Met-Arg-Phe-NH2, callisulfakinin II. However, this peptide was not identified in the fly head extracts. Confocal laser scanning immunocytochemical studies with antisera raised against the synthetic undecapeptide C-terminal fragment of drosulfakinin II from D. melanogaster, Asp-Gln-Phe-Asp-Asp-Tyr(SO3)- Gly-His-Met-Arg-Phe-NH2, revealed only four pairs of sulfakinin neurones in the brain of C. vomitoria and no others anywhere else in the neural, endocrine or gut tissues. In situ hybridisation studies with a digoxigenin-labelled sulfakinin gene probe (from the blowfly Lucilia cuprina) also revealed only four pairs of neurones in the brain. The perikarya of two pairs of cells are situated medially in the caudo-dorsal region, close to the roots of the ocellar nerve. The other perikarya are slightly more posterior and lateral. Although it has been suggested by several authors that the insect sulfakinins are homologous to the vertebrate peptides gastrin and cholecystokinin, such arguments (based essentially on C-terminal structural similarities) do not take account of important differences in the C-terminal tetrapeptide. His-Met-Arg-Phe-NH2 in the sulfakinins, compared with Trp-Met-Asp-Phe-NH2 in gastrin and cholecystokinin. Furthermore, whereas the sulfakinin neurons of C. vomitoria are small in number and have a very specialised location, a greater number of cells throughout the nervous system react positively to gastrin/cholecystokinin antisera. Chromatographic profiles of the present study also revealed peaks of gastrin/cholecystokinin-immunoreactive material separate from the sulfakinin peptides. This evidence suggests that the insect and vertebrate peptides may not necessarily be homologous.
The prohormonegene encodingthe Leu-callatostatinpeptideshas been isolatedfrom a Calliphora wmitor... more The prohormonegene encodingthe Leu-callatostatinpeptideshas been isolatedfrom a Calliphora wmitoria genomicDNA library and its homologuewas cloned from genomicand cDNA librariesof anotherblowflyspecies, Lucilia crqrinu. Gene and prohormone structure and organisationare essentially identical in the two species. The Leu-callatostatingene consists of at least 3 exons. The prohormoneis encodedon exonstwo and threeand the two blocksof putativeLeu-callatostatinpeptidesare carriedon separateexons.It is 180 amino-acidslong, begins with a short signal peptide and containstwo blocks of tandemlyarrangedLeu-callatostatinpeptides separatedby an acidic spacer region. The prohormonecontains 5 copies of the C-terminal sequence-YXFGL characteristicof the Leu-callatostatinfamily. Complete endoproteolyticprocessingat all possible pairs of basic amino acids would generate 5 different Leu-callatostatinoctapeptides.TwolargerLeu-callatostatins couldbe releasedif processingwas not completeat two of the sites.Noneof the 3 peptidesencodedin the first block was identifiedin previouspurificationstudiesof the callatostatinpeptides.The secondblock, locatedat the carboxylend of the prohormone, containstwopeptidesequencesidenticalto the previouslyisolatedLeu-callatostatins1 and 4. The absenceof independentcopies of Leu-callatostatins2 and 3 on the prohormoneestablishesthat endoproteolyticcleavageof the precursordoes not invariablyproceedto completionand that Leu-callatostatin2 must be derivedby N-terminalprocessingof the parent peptideLeu-callatostatin1. ReversetranscriptasePCR analysisof mRNAfrombrain and midgut,the two major sites of Leu-callatostatin expression,shows that the prohormonesequenceat these two sites is identical,ruling out the possibilitythat differentpopulationsof peptidesare expressedin these two tissues as a result of alternativeRNA splicing.
TARA D. SUTHERLAND's2 and PETER D. EAST' 'CSIRO,DivisionofEntomology, Canberra, Au... more TARA D. SUTHERLAND's2 and PETER D. EAST' 'CSIRO,DivisionofEntomology, Canberra, Australia, and ?Department of Entomology, University of Arizona, Tucson, Arizona, USA ... Abstract. Juvenile Hormone I11 bisepoxide synthesis by ring gland complexes from third-...
Uploads
Papers by Peter East