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At least 19 recordsLinked to original sources
PubMed1975

[Phase morphometric differences among Locusta migratoria cinerascens, Locusta migratoria migratorioides, and their mutant albinos (Orthoptera)].

A first canonical variate analysis (factor analysis) of two geographic strains of L. m. shows that the same axes distinguish crowded from isolated animals as well as their geographical origins. Two other analyses between normal and albino strains of both localities show no differences for one strain; however for the other strain, the pigmentary mutation coincides with a solitary tendency.

Animals↗
PubMed1995

Evidence for the hormonal function of a CRF-related diuretic peptide (Locusta-DP) in Locusta migratoria

Locusta-DP is a corticotropin-releasing factor (CRF)-related diuretic peptide isolated from the migratory locust Locusta migratoria. At nanomolar concentrations, synthetic Locusta-DP stimulated fluid secretion and cyclic AMP production by Malpighian tubules isolated in vitro and increased the rate of amaranth clearance in starved locusts to levels comparable with those observed during post-feeding diuresis. The peptide also caused a marked (approximately 10 %), but short-lived, reduction in the haemolymph volume of starved locusts. A polyclonal antiserum raised against Locusta-DP(29-46) was shown to block peptidergic signal transfer in vitro and in vivo. Pre-treatment of Locusta-DP (5 nmol l-1) with antiserum diluted 1:100 resulted in a rapid reduction in the free peptide concentration to less than 1 nmol l-1, the threshold for a measurable effect on cyclic AMP production by isolated tubules. In intact insects, passive immunization with Locusta-DP antiserum blocked increases in the rate of amaranth clearance in response to exogenous diuretic peptide or in response to feeding. The latter was due specifically to the binding of Locusta-DP, because when the relevant antibodies were preadsorbed with Locusta-DP(29-46), the antiserum had no effect on amaranth clearance by recently fed insects. This provides unequivocal evidence of a hormonal function for Locusta-DP in the control of primary urine production.

Journal Article↗
PubMed1994

Nervous control of juvenile hormone biosynthesis in Locusta migratoria.

In Locusta migratoria migratorioides R. and F., two types of brain neurons innervate the juvenile hormone (JH)-producing corpora allata (CA). Thirteen cells in each pars lateralis (PL) innervate the ipsilateral CA, while four cells (two in each PL) innervate both glands. We investigated possible influences of these two neuronal types on JH production by a newly developed method. A radiochemical assay was used to measure hourly JH production by a CA with intact nerve connections to the brain. Then, changes in hormone production due to selective nerve stimulation or transection were assessed. In control preparations JH production per h remained approximately constant for at least 9 h. Simultaneous electrical stimulation of all neurons innervating one CA (i.e., 13 ipsilateral plus 4 bilaterally innervating cells) always inhibited JH production, while their transection led to a rapid progressive increase in JH biosynthesis in CA from females with oocytes longer than 4.5 mm. Thus, there is strong neurally mediated inhibition of the CA at certain phases of the vitellogenic cycle. The dramatic effects of nerve transection show that in vitro rates of JH production are an unreliable indicator of in vivo levels. Selective stimulation of the four neurons innervating both CA suggests that they do modulate JH biosynthesis but the effect varies qualitatively depending on the phase of the vitellogenic cycle.

Animals↗
PubMed1995

Transovarial transmission of Nosema locustae (Microsporida: Nosematidae) in the migratory locust Locusta migratoria migratorioides.

Nosema locustae, a microsporidian parasite of locusts and grasshoppers, was transovarially transmitted to the progeny of infected Locusta migratoria reared for up to F14 generations. The mortality of infected progeny in each generation was higher than that of uninfected controls and ranged from 67.6% to 95.5%. Infected female survivors transmitted the microsporidium to the progeny via eggs. The developing eggs harboured vegetative stages of N. locustae, and development of the microsporidium occurred during embryonation. Spores accumulated in the yolk and, after blastokinesis, both the yolk and the spores were enclosed in the midgut of the embryo. Germinated spores infected the functional midgut epithelium and invaded internal tissues. The mortality of newly hatched instars was high when embryonic tissue had been infected during development.

Animals↗
PubMed2006

LocustDB: a relational database for the transcriptome and biology of the migratory locust (Locusta migratoria).

BACKGROUND: The migratory locust (Locusta migratoria) is an orthopteran pest and a representative member of hemimetabolous insects for biological studies. Its transcriptomic data provide invaluable information for molecular entomology and pave a way for the comparative research of other medically, agronomically, and ecologically relevant insects. We developed the first transcriptomic database of the locust (LocustDB), building necessary infrastructures to integrate, organize, and retrieve data that are either currently available or to be acquired in the future. DESCRIPTION: LocustDB currently hosts 45,474 high-quality EST sequences from the locust, which were assembled into 12,161 unigenes. It, through user-friendly web interfaces, allows investigators to freely access sequence data, including homologous/orthologous sequences, functional annotations, and pathway analysis, based on conserved orthologous groups (COG), gene ontology (GO), protein domain (InterPro), and functional pathways (KEGG). It also provides information from comparative analysis based on data from the migratory locust and five other invertebrate species, including the silkworm, the honeybee, the fruitfly, the mosquito and the nematode. The website address of LocustDB is http://locustdb.genomics.org.cn/. CONCLUSION: LocustDB starts with the first transcriptome information for an orthopteran and hemimetabolous insect and will be extended to provide a framework for incorporating in-coming genomic data of relevant insect groups and a workbench for cross-species comparative studies.

Animals↗
PubMed1991

Characterization of a diuretic peptide from Locusta migratoria.

A diuretic peptide Locusta-DP, identified by its ability to increase cyclic AMP production in locust Malpighian tubules in vitro, has been isolated and characterized from whole heads of Locusta migratoria. The purified peptide stimulates fluid secretion by Malpighian tubules maximally in vitro. The primary structure of Locusta-DP was established as a 46 residue amidated peptide: MGMGPSLSIVNPMDVLRQRLLLEIARRRLRDAEEQIKANKDFLQQI-NH2. Locusta-DP has 48% sequence identity with Acheta-DP and 49% identity with Manduca-DH, and provides further evidence for the presence of a family of diuretic peptides in insects.

Amino Acid Sequence↗
PubMed2005

Differences in egg thermotolerance between tropical and temperate populations of the migratory locust Locusta migratoria (Orthoptera: Acridiidae).

The migratory locust Locusta migratoria L., which is widely distributed throughout the world, exhibits within- and between-population variation in cold tolerance. To understand physiological adaptation in populations, we studied the genetic basis of thermotolerance in Hainan (tropical) and Liaoning (temperate) populations and measured expression of Hsp70 and Hsp90 mRNA in both populations at low (0 degrees C) and high temperatures (40 degrees C). Phenotypic variation of thermotolerance is heritable. Heritable characteristics differed among different stages of locust egg development, as well as among different measures of thermotolerance. Nuclear genetic factors, rather than cytoplasmic factors, contribute to differences in cold tolerance between the tropical and temperate populations of the migratory locust; for heat tolerance, maternal effects were involved in three stages of egg development. Expression of Hsp90 mRNA was induced in temperate population after heat shock (40 degrees C x 12h), whereas expression of Hsp70 and 90 was induced in tropical population after cold shock (0 degrees C x 12h). We suggest that thermotolerance of locust eggs has a complex genetic basis and heat shock proteins may be involved in differences of thermotolerance between locust populations.

Acclimatization↗
PubMed2004

Juvenile hormone-dependent motor activation in the adult locust Locusta migratoria.

Abdominal motoneurones of the locust Locusta migratoria were investigated in immature, mature and allatectomised females to compare their response characteristics during reproductive development. These motoneurones were chosen because they control muscles which are involved in extreme lengthening during egg-laying behaviour. The study focused on changes in motoneurone firing activity and its possible regulation by juvenile hormone. In isolated nerve-muscle preparations, increased resting motor activity was found in mature (>14 days) but not in immature females (<5 days). Removing the corpora allata, the gland producing juvenile hormone in insects, prevented increased motor activity. Stimulus evoked activation of the motor system led to a characteristic burst of action potentials which lasted for a few seconds. The time-course and amount of activation changed significantly during reproductive development. Mature females displayed longer lasting and higher activity than immature or allatectomised females, but only those segments involved in egg-laying were found to express the altered firing properties. Single cell analysis of motoneurone dendritic morphology or membrane properties revealed no evidence that could be causative for the activity changes seen during reproductive development. The results suggest that altered motoneurone activity serves to adapt females to the neuromuscular requirements of egg-laying behaviour.

Action Potentials↗
PubMed1993

A comparison of the effects of two putative diuretic hormones from Locusta migratoria on isolated locust malpighian tubules.

Previous work has shown that a peptide related to arginine vasopressin is present in the suboesophageal ganglion of the locust, Locusta migratoria. This peptide was determined to be an anti-parallel dimer of the nonapeptide Cys-Leu-Ile-Thr-Asn-Cys-Pro-Arg-Gly-NH2 and was reported to stimulate cyclic AMP production and fluid secretion in a combined Malpighian tubules and midgut preparation from locusts. For these reasons the peptide has been called the arginine-vasopressin-like insect diuretic hormone (AVP-like IDH). Recently, a second diuretic peptide (Locusta-DP), which is related to corticotropin releasing factor, has been identified: this is a potent stimulant of fluid secretion and cyclic AMP production by isolated locust tubules. Because water balance in insects is likely to be controlled by a cocktail of hormones acting on both Malpighian tubules and hindgut, this study directly compares the activity of these two peptides in fluid secretion and cyclic AMP production bioassays on one target organ, the isolated Malpighian tubule of Locusta migratoria. Locusta-DP was synthesised directly, whereas the dimeric AVP-like IDH was obtained by oxidation of a synthetic nonapeptide monomer. Products were separated by RP-HPLC and their structures unequivocally confirmed by enzymatic digestion, sequence analysis and electrospray mass spectrometry. We show that Locusta-DP causes strong stimulation of fluid secretion and cyclic AMP production, whereas the AVP-like IDH has no effect in either assay. These findings are discussed in the light of recent work on the anatomy and physiology of the vasopressin-like immunoreactive (VPLI) neurones in the suboesophageal ganglion of Locusta migratoria, the proposed source of the AVP-like peptide.

Amino Acid Sequence↗
PubMed1988

Projection areas and branching patterns of the tympanal receptor cells in migratory locusts, Locusta migratoria and Schistocerca gregaria.

In Locusta migratoria and Schistocerca gregaria, the projection areas and branching patterns of the tympanal receptor cells in the thoracic ganglia were revealed. Four auditory neuropiles can be distinguished on each side of the ventral cord, always located in the anterior part of the ring tract in each neuromere (two in the meta-, one in the meso-, and one in the prothoracic ganglion). Some of the receptor fibres ascend to the suboesophageal ganglion. There are distinct subdivisions within the auditory, frontal metathoracic and mesothoracic neuropiles. The arrangement of the terminal arborisations of the four types of tympanal receptor cells according to their different frequency-intensity responses is somatotopic and similar in the two ganglia. Here the receptor cells of type-1 form a restricted lateroventral arborisation. Cells of type-4 occupy the caudal part with a dorsorostral extension. Cells of type-2 and -3 arborise in a subdivision between both. Most of the stained low-frequency receptors (type-1, -2, and -3) terminate either in the metathoracic or, predominantly, in the mesothoracic ganglion. In contrast, the high-frequency cells (type-4) ascend to the prothoracic ganglion. The receptor fibres of the different types of receptor cells differ in diameter.

Animals↗
PubMed1979

Ultrastructure of the muscles of the dorsal diaphragm in Locusta migratoria.

The alary muscles of Locusta migratoria adults make up the major tissue of the dorsal diaphragm which separates pericardial and perivisceral sinuses in the abdomen. The alary muscles are striated with a sarcomere at rest measuring about 9 microns. The Z-line has a staggered-beaded arrangement with A-bands and I-bands readily discernable. Thick myofilaments are surrounded by 10 or more thin filaments. The sarcoplasm has few mitochondria near the area of the Z-line, dyads are present and sarcoplasmic reticulum is poorly developed. Axons which innervate the alary muscle are either contained within invaginated folds of the sarcolemma of the muscle cells or the muscle cells send finger-like projections to envelop the axons. The synaptic terminals contain synaptic vesicles between 40 and 45 nm in diameter and a few electron-dense granules near or less than 170 nm in diameter. Away from synaptic terminals the axon profiles show few or no granules. The axons are accompanied everywhere by well-developed glial cells. This then is not typical neurosecretomotor innervation, however, the presence of electron-dense granules suggests the possibility of peptidergic neurotransmission.

Animals↗
PubMedDate not supplied

Elimination of C-6-hydrogen during the formation of ecdysteroids from cholesterol in Locusta migratoria ovaries.

Being administered to Locusta migratoria adult females, [6-3H, 4-14C]cholesterol was incorporated into ecdysone and 2-deoxyecdysone. The ratio of 3H/14C of the two ecdysteroids isolated from newly laid eggs revealed that C-6-hydrogen of cholesterol was eliminated during the conversion to ecdysteroids in the ovaries of the insects. Thus, a hypothetical mechanism involving migration of the C-6-hydrogen to the C-5 position in the formation of A/B cis junction turned out to be less likely.

Animals↗
PubMed1976

[Role of phagocytosis and soluble antibacterial factors in experimental immunization of Locusta migratoria].

Last instar larvae of Locusta migratoria can be protected ("vaccinated") against lethal doses of Bacillus thuringiensis by previous injections of low doses of this pathogen. If iron saccharate is injected in to larvae prior to the administration of the "vaccinating" dose of Bacillus thuringiensis, no antibacterial protection can be induced. Injection of iron saccharate in to "vaccinated" larvae does not interfere with the induced protection; such larvae resist lethal doses.

Animals↗
PubMed1983

The absolute configuration of precocene I dihydrodiols produced by metabolism of precocene I by corpora allata of Locusta migratoria, in vitro.

The corpora allata from adult female Locusta migratoria metabolize precocene I (7-methoxy-2,2-dimethyl-2H-benzo [b]pyran to cis- & trans-precocene I dihydrodiols (3,4-dihydro-7-methoxy-2,2-dimethyl-2H-benzo [b]pyran-3,4-diol). Derivatization of the dihydrodiols with (-)menthoxy acetyl chloride allowed complete resolution of all four optical isomers. When [4-3H]-precocene I was incubated in vitro with Locusta migratoria corpora allata, it was metabolized stereospecifically to (-)trans-(3R,4S) and (+)cis-(3R,4R) dihydrodiols. Approximately half the precosyl residues bound to cellular macromolecules were discharged by heating to 95 degrees C at neutral pH, as dihydrodiols of the same stereochemistry.

Benzopyrans↗
PubMed2002

Possible involvement of ecdysteroids in photoperiodically induced suppresion of ovarian development in a Japanese strain of the migratory locust, Locusta migratoria.

In a Japanese population of Locusta migratoria, adult females become reproductively inactive under crowding and long days (LD) and reproductively active under crowding and short days (SD). The identity and titre of ecdysteroids in the haemolymph and ovaries from adult females reared under SD and LD were investigated by RIA/HPLC. The effects of exogenous juvenile hormone (JH) III treatments on the termination of such reproductive arrest and ecdysteroid contents in LD females were also examined. In general, ecdysteroid titres in both haemolymph and ovaries were significantly higher in reproductively active SD females than in reproductively inactive LD females. A clear difference was also observed in oocyte growth between SD and LD individuals. JH III applications (three consecutive topical applications, 150 &mgr;g per insect per day from day 3) stimulated ovarian development in LD females and significantly increased the haemolymph and ovarian ecdysteroids to a level comparable to that of reproductively active SD adult females.

Journal Article↗
PubMedDate not supplied

[New studies on 3-dehydroecdysteroids in the biosynthetic pathway of ecdysone in Locusta migratoria].

Prothoracic glands of the locust, Locusta migratoria, incubated in vitro, converted in the same manner 3-dehydroketodiol (14 alpha-hydroxy-5 beta-cholest-7-en-3,6-dione) tritiated either on the side chain (22,23,24,25)3H4 or on the nucleus (1,2)3H2. Conversion products always appeared in two forms: one oxidized at C-3 corresponding with 3-dehydroecdysteroids, and the other corresponding with "classical" ecdysteroids which are usually obtained by conversion of ketodiol. All the different intermediate ecdysteroids between ketodiol and ecdysone are presents. A non-hemolymphatic reductase is conceivably responsible for the conversion of 3-dehydroecdysteroids at one or several places in the course of the biosynthetic pathway. Quantitatively the two forms (oxidized or hydroxylated at C-3) appeared in changeable ratios according to the different ecdysteroids but with a prevailing tendency to 1:1. The specificity of the conversion from nucleus-tritiated-dehydroketodiol depended on an enormous production of polar degradation products (more than 50% of total radioactivity). Consequently the quantities of 3-dehydro- and 3-hydroxy-ecdysteroids were lower than those which could be obtained after the conversion of side-chain-tritiated-3-dehydroketodiol. By means of an incubation with locust-larval-hemolymph, each 3-dehydroecdysteroid was totally (or at least in a great part: 3-dehydro-2-deoxyecdysone) converted into the corresponding reduced ecdysteroid. This fact confirms the reducing function of the hemolymph.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Distribution of locustamyotropin-like immunoreactivity in the nervous system of Locusta migratoria.

Locustamyotropin-like immunoreactivity was visualized in the nervous system of Locusta migratoria by means of the peroxidase antiperoxidase method. Highly specific antibodies to the carboxy-terminus of the locustamyotropins were obtained by elution through an affinity column to which Lom-MT II was covalently bound. Specific cells in the nervous system of Locusta migratoria contain substances immunoreactive to anti-locustamyotropin. In total, about 100 cells immunoreactive to the Lom-MT-II antiserum were detected in the head ganglia, in the abdominal neuromeres of the metathoracic ganglion, and in the five free abdominal ganglia. In the brain, immunoreactive cell groups were situated in the inner and outer edge of the tritocerebrum. Prominent axon bundles tightly surround the tractus I to the corpora cardiaca. The corpora allata were innervated by the nervus corporis allati I coming from the corpora cardiaca and by fibers in the nervus corporis allati II originating from cell bodies in the suboesophageal ganglion. Immunoreactive cell bodies in the suboesophageal and abdominal ganglia are distributed along the anterior posterior midline axis, both dorsally and ventrally. The processes of the cell bodies in the abdominal ganglia leave the ganglia and were traced in the respective median nerves into the neurohaemal organs. Since the Lom-MT-II antiserum cross-reacts with all peptides of the locustamyotropin family that have a carboxy-terminus in common, these cells may contain one or several locustamyotropins. The Lom-MT antiserum also recognizes pheromone biosynthesis activating neurohormone, as was revealed by the intensive labeling of suboesophageal cell bodies in Bombyx mori.

Amino Acid Sequence↗
PubMed1989

The superimposition of heat-induced chiasma frequency changes in Locusta migratoria.

Inbred laboratory stocks of the locust Locusta migratoria were used in two different types of experiment involving the superimposition of heat-induced changes in chiasma frequency. The first involved the administration of two heat-treatments at 40 degrees C alternating with a return to 30 degrees C. This was designed to superimpose two small changes, which have been called Effect 1 (increase) and Effect 2 (decrease) upon a single larger Effect 4 (increase). Unlike the response previously reported in a similar experiment carried out with Schistocerca gregaria, an intermediate response was found here in Locusta, with recognisable Effects 1 and 2 components being superimposed upon a reduced Effect 4 increase. The aim of the second experiment was to determine the effects of chiasma frequency of an alternating programme of one day at 40 degrees C, followed by a return to 30 degrees C, maintained for a period of several weeks. This would continually superimpose small effects of all types upon one another. It was found that, rather than falling, as might have been expected, chiasma frequencies rose substantially after the first five days and remained well above control levels for the remainder of the experiment. This readily induced increase in recombination frequencies could be of practical application to those breeders interested in the production of new varieties by conventional selection.

Animals↗