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C Strambi

Publications and source records attributed to C Strambi.

34 records · Page 2Linked to original sources
PubMed1986

Opposite effects of ecdysone and 20-hydroxyecdysone on in vitro uterus motility of a tsetse fly.

In order to examine the possible effects of ecdysteroids on parturition, we studied in vitro the influence of ecdysone and 20-hydroxyecdysone on the motility of isolated uterus from virgin and pregnant female tsetse fly (Glossina fuscipes). Ecdysone initiates phasic uterine contractions or enhances the frequency of preexisting contractile activity. In contrast, uterine contractions are decreased or abolished by 20-hydroxyecdysone. Pharmacological data indicate that tsetse fly uterus exhibits myogenic and nerve-evoked contractions. Ecdysteroids mainly act on nervous structures that control muscle contractions. Our results provide evidence for a specific action of ecdysteroids on a nerve-muscle target involved in female reproduction.

Animals↗
PubMed1986

In vivo application of HRP crystals: a new and efficient method for tracing neural connections in insects.

Solid HRP pellets prepared with a 2.5% Triton X-100 aqueous solution were implanted either into corpora allata or applied onto neurohemal organs of a cricket. The method presents two advantages: it allows one to perform "in vivo" instead of "in vitro" experiments, and detergent HRP pellets are easy to manipulate. Thus, this method combines simplicity with accuracy and appears to be very useful in tracing neural connections in the insect nervous system.

Animals↗
PubMed1984

Temporal variations of hemolymph esterase activity and juvenile hormone titers during ovocyte maturation in Acheta domesticus (Orthoptera).

Using in vitro methods, juvenile hormone (JH) esterase activity and alpha-naphthylacetate esterase activity were determined in the hemolymph during the first reproductive cycle of the house cricket, Acheta domesticus. Biochemical properties of the hemolymph JH esterase were studied. alpha-Naphthylacetate esterases increased during the first gonotrophic cycle: peaks of their activity could be observed concomitant with peaks of JH esterase activity. The fluctuations in JH esterase activity correlated with those of hemolymph JH titers. The results are discussed.

Animals↗
PubMed1984

Normal and experimentally induced changes in hormonal hemolymph titers during parental behavior of the earwig Labidura riparia.

The reproductive cycle of Labidura riparia includes two distinct phases of behavior: a feeding and sexual phase followed by a parental and fasting phase. These phases correspond to two contrasting physiological phases (vitellogenesis, followed by ovarian inactivity). These correlations have been verified by correlating radioimmunoassay (RIA) measurements of the levels of circulating juvenile hormones (JH) and ecdysteroids with ovarian state during the first reproductive cycle. Similar studies were also made after experimentally suppressing parental activity (care of eggs) either by depriving females of their eggs or by force-feeding during the egg-care phase. Taking eggs away without feeding caused the disappearance of parental behavior and a short lived period of vitellogenesis. Likewise, feeding in the presence of eggs resulted in vitellogenesis and disappearance of egg-care behavior. Thus, it appears that in order for the parental phase to develop normally it is necessary to preserve the proper external conditions (the presence of eggs) and physiological conditions (fasting).

Animals↗
PubMed1984

Simultaneous determination of juvenile hormone and ecdysteroid titers in the hemolymph of bumblebee prepupae (Bombus hypnorum and B. terrestris).

By means of radioimmunoassays the titer of juvenile hormone and ecdysteroids in the hemolymph was simultaneously determined in single prepupae throughout prepupal development. The concentrations of both hormones increase and show a peak, thereafter the titers fall sharply at larval/pupal ecdysis. Caste-specific differences in the time sequence of titer changes and in the concentration of JH are discussed.

Animals↗
PubMed1981

Radioimmunoassay of insect juvenile hormones and of their diol derivatives.

We have developed a radioimmunoassay for insect juvenile hormones. The C18 hormone (JH I) was first converted into diol by opening the 10, 11-epoxy ring. Diol was then succinylated and coupled to human serum albumin to make it immunogenic. High titer antisera were obtained from immunized rabbits. Succinyl juvenile hormone was also coupled to the peptide glycyltyrosine and iodinated so as to form a water-soluble 125I-labelled analogue well recognized by antibodies (60% bound by the 1/2000 000 dilution of antiserum routinely used in radioimmunoassay). Standards and biological samples were treated with acidic dioxane in order to convert each hormone into its corresponding diol. In this way, the sensitivity threshold of the radioimmunoassay was under 0.015 pmol. All three diols were equally recognized by the antibodies. Hormones JH I, JH II and JH III could be assayed separately as diols after thin-layer chromatography or high-pressure liquid chromatography purification of the biological samples. This method was used to determine physiological levels of juvenile hormones in the haemolymph of several insects at different development stages including embryos and in corpora allata cultures.

Animals↗
PubMed1977

[Evolution of the adipose tissue during the postembryonic development in Coleoptera Catopidae. I. Studies in Choleva fagniezi and Speophyes lucidulus (author's transl)].

Cytological studies of the fat body have been performed during the postembryonic development of 2 Coleoptera Catopidae: Choleva fagniezi and Speophyes lucidulus. As in other insects, the cells store large amounts of glycogen, lipids and proteins during the larval life; these reserves would be lysed and used during the metamorphosis. According to the species, protein globules are constituted at different larval life periods. In Choleva fagniezi they appear during the 3rd and last larval instar. In Speophyes lucidulus, protein globules appear during the 10 first days of the 1st larval instar. In the prenymphs of the 2 species, the protein globules become rich in RNA.

Adipose Tissue↗
PubMedDate not supplied

Immunocytochemical mapping of an RDL-like GABA receptor subunit and of GABA in brain structures related to learning and memory in the cricket Acheta domesticus.

The distribution of putative RDL-like GABA receptors and of gamma-aminobutyric acid (GABA) in the brain of the adult house cricket Acheta domesticus was studied using specific antisera. Special attention was given to brain structures known to be related to learning and memory. The main immunostaining for the RDL-like GABA receptor was observed in mushroom bodies, in particular the upper part of mushroom body peduncle and the two arms of the posterior calyx. Weaker immunostaining was detected in the distal part of the peduncle and in the alpha and beta lobes. The dorso- and ventrolateral protocerebrum neuropils appeared rich in RDL-like GABA receptors. Staining was also detected in the glomeruli of the antennal lobe, as well as in the ellipsoid body of the central complex. Many neurons clustered in groups exhibit GABA-like immunoreactivity. Tracts that were strongly immunostained innervated both the calyces and the lobes of mushroom bodies. The glomeruli of the antennal lobe, the ellipsoid body, as well as neuropils of the dorso- and ventrolateral protocerebrum were also rich in GABA-like immunoreactivity. The data demonstrated a good correlation between the distribution of the GABA-like and of the RDL-like GABA receptor immunoreactivity. The prominent distribution of RDL-like GABA receptor subunits, in particular areas of mushroom bodies and antennal lobes, underlines the importance of inhibitory signals in information processing in these major integrative centers of the insect brain.

Animals↗