Search results for "Insect"
showing 10 items of 2033 documents
Postembryonic development of Zophobas atratus Fab. (Coleoptera: Tenebrionidae) under crowded or isolated conditions and effects of juvenile hormone a…
1995
Abstract Pupation in Zophobas atratus is dependent on isolation and this provides a model for study of the onset of metamorphosis in beetles. We have analyzed the effects of isolation vs grouping on certain developmental parameters; the number of larval instars; their duration and weight. Sex differences were detected, such as the occurrence of regressive moults in females. Moreover, the development of Z. atratus is discussed in relation to Tenebrio molitor , the physiological timing of which appeared in part extendable to Z. atratus . Experiments show that 4–6 days of isolation are required for commencement of metamorphosis, as indicated by an immobile crooked posture observed at the end o…
Developmental changes and acetylcholinesterase activity in the metamorphosing brain ofTenebrio molitor: Correlation to ecdysteroid titers
1994
The brain of Tenebrio molitor exhibited marked fluctuations in acetylcholinesterase (AChE) activity throughout metamorphosis. This was true AChE activity, since it was inhibited by high substrate concentrations and by 10 μM of the specific AChE inhibitor BW284C51 [(1,5-bis'4-allyldimethylammoniumphenyl)-pentan-3-one dibromide] but not by iso-OMPA (tetraisopropylpyrophosphoramide), a cholinesterase (but not AChE) inhibitor. The histochemical AChE activity was localized in the neuropile and the nuclear envelope of neurons and glial cells. The enzyme extracted from brains with 1% Triton X-100 and 1 M NaCl sedimented as a single peak in a sucrose density gradient, with a sedimentation coefficie…
Control of ovarian steroidogenesis by insulin-like peptides in the blowfly (Phormia regina).
2004
0022–0795/04/0181–147; This study investigated the ability of insulin and of insect insulin-like peptides (ILPs) to stimulate ovarian steroidogenesis in the blowfly Phormia regina. Bovine insulin was active on ovaries isolated in vitro, which showed an age-dependent sensitivity; this peptide progressively stimulated steroidogenesis in ovaries isolated from the third day after adult molt, but not in younger ones, and had maximal activity after the fifth day. This stimulatory effect was observed equally from females reared in the presence or in the absence of males, excluding a regulatory effect of mating. The mode of action of insulin in blowflies did not involve cAMP, but triggered a specif…
Vitellogenesis inhibition in Oncopeltus fasciatus females (Heteroptera: Lygaeidae) exposed to cadmium
2005
Abstract Newly moulted females of the insect Oncopeltus fasciatus were exposed to cadmium (Cd) dissolved in the drinking water (50–400 mg l −1 Cd) for 5 days. Cd exposure delayed ovarian maturation and inhibited egg production. Exposure to Cd, moreover, decreased hemolymph levels of the two major vitellogenin polypeptides of O. fasciatus , VG1 and VG2, in a concentration-dependent way, probably by a reduction in their synthesis. The ovarian levels of VG1 and VG2 were also decreased in Cd-exposed females. It was next investigated whether Cd effects might be a consequence of the endocrine disruption of vitellogenin synthesis, which is controlled by juvenile hormone (JH). JH replacement therap…
The toxic and lethal effects of the trehalase inhibitor trehazolin in locusts are caused by hypoglycaemia
2003
SUMMARY The main blood sugar of locusts is trehalose, which is hydrolysed to two glucose units by trehalase. Homogenates of locust flight muscles are rich in trehalase activity, which is bound to membranes. A minor fraction of trehalase is in an overt form while the remainder is latent, i.e. active only after impairing membrane integrity. Trehazolin, an antibiotic pseudosaccharide,inhibits locust flight muscle trehalase with apparent Ki-and EC50 values of 10–8 mol l–1and 10–7 mol l–1, respectively. Trehazolin is insecticidal: 50 μg injected into locusts completely and selectively blocked the overt form of muscle trehalase (with little effect on latent activity) and killed 50% of the insects…
Ovicidal Activity of Maternally Applied Ecdysteroids in the Large Milkweed Bug (Heteroptera: Lygaeidae)
1982
Exogenous ecdysteroids (ecdysone, 20-hydroxyecdysone and makisterone A) administered to reproducing females of Oncopelus fasciatus (Dallas) reduced egg hatch drastically. The ovicidal activity apparently stemmed from ecdysteroids—unchanged hormone or metabolites—transferred from mother into oocyte. Different stages of embryogenesis were affected. Makisterone A, the predominant ecdysteroid in normal embryos, is by far the most effective ecdysteroid.
The non-appearance of female-specific proteins in male Spilostethus pandurus)
1990
1. 1. Female-specific peptides can be detected by SDS-PAGE in the haemolymph when the female insects are 48 hr old. 2. 2. The age of the male insect at the moment of treatment with juvenile hormone I (JH I), JH III or ecdysone has no influence on the induction of the female-specific bands in male S. pandurus. 3. 3. Male insects exposed to the hormones for periods of time longer than 24 hr were also unable to show female-specific bands in their haemolymph. Consecutive treatments with JH were unable to induce these peptides in the males.
A stinging wasp in the stomach: accidental endoscopic diagnosis of a systemic anaphylactic reaction.
2015
of a proton pump inhibitor and prokinetic treatment. Because of her medical history, an upper gastrointestinal (GI) endoscopy was performed. We discovered, in the proximalpartof theantrumonthegreater curvature, an intact dead wasp with its sting visible and an underlying slightly swollen red welt in the area of the sting
Intrarectal immunization with rotavirus 2/6 virus-like particles induces an antirotavirus immune response localized in the intestinal mucosa and prot…
2006
ABSTRACTRotavirus (RV) is the main etiological agent of severe gastroenteritis in infants, and vaccination seems the most effective way to control the disease. Recombinant rotavirus-like particles composed of the viral protein 6 (VP6) and VP2 (2/6-VLPs) have been reported to induce protective immunity in mice when administered by the intranasal (i.n.) route. In this study, we show that administration of 2/6-VLPs by the intrarectal (i.r.) route together with either cholera toxin (CT) or a CpG-containing oligodeoxynucleotide as the adjuvant protects adult mice against RV infection. Moreover, when CT is used, RV shedding in animals immunized by the i.r. route is even reduced in comparison with…
Software/Hardware Issues in Modelling Insect Brain Architecture
2011
The concept of cognitive abilities is commonly associated to humans and animals like mammals, birds and others. Nevertheless, in the last years several research groups have intensified the studies on insects that posses a much simpler brain structure even if they are able to show interesting memory and learning capabilities. In this paper a survey on some key results obtained in a joint research activity among Engineers and Neurogeneticians is reported. They were focussed toward the design and implementation of a model of the insect brain inspired by the Drosophila melanogaster. Particular attention was paid to the main neural centers the Mushroom Bodies and the Central Complex. Moreover a …