A reappraisal of the hormonal regulation of larval fat body histolysis in femaleDrosophila melanogaster

The histolysis of larval fat body cells in adult femaleDrosophila melanogaster was examined in wild type and mutant animals. The fat body cells of wild type (Canton-S),apterous ^56f homozygotes,apterous ^78jts homozygotes and heterozygotes,apterous ⁴/+, ecdysoneless¹ homozygotes and heterozygotes all underwent histolysis normally during the 72 h following adult eclosion. Only in the case ofap ⁴/ap⁴ adults did the cells fail to histolyze normally. The fat body cells of both diapausing and non-diapausing wild type females underwent histolysis at the same rate. Attempts to demonstrate histolysis in vitro were unsuccessful, even in the presence of juvenile hormones (JHs), larval ring glands, or adult ovaries. In all strains other than theap ⁴ homozygotes, a significant proportion of larval fat body cells were dead at any time while theap ⁴/ap⁴ animals, almost all cells remained viable. It is postulated that fat body cell lysis following eclosion is not a JH-mediated event, but is elicited by an as yet unidentified factor(s), possibly originating in the ovary.     

Changes in binding of JH-III in hemolymph of adult femaleLocusta migratoria

Summary Hemolymph from adult femaleLocusta migratoria migratorioides was analyzed for binding of juvenile hormone III (JH-III) after allatectomy and transection of thenervus corporis allati 1 (NCA-I). These operations did not affect the apparent dissociation constant of the binding (Kd=3.3 10^–8 M). The concentration of binding sites exhibited fluctuations in relation to age and type of operation: an increased concentration of binding sites in females with disconnected corpora allata and a decreased concentration in allatectomized females. The changes in concentration of binding sites was not due to differences in water content or hemolymph volume in operated animals. The hemolymph protein concentration was reduced after NCA-I transection and even more after allatectomy. However, variations in protein concentration did not correlate with changes in concentration of JH-III binding sites. The changes in binding site concentration were related to changes in JH-titer.     

The transfer of juvenile hormone from male to female during mating in the Cecropia silkmoth

Summary The juvenile hormone (JH) stored in the accessory sex glands (ASG) of adult maleHyalophora cecropia (L.) originates both from sequestration of circulating hormone and from JH synthesized de novo in the ASG from JH acid taken up from the hemolymph. The secretions present in the lumina of the ASG contain most of the accumulated JH. During mating, endogenous JH, labeled biosynthetically via injected [³H-methyl]-methionine, is transferred along with the other seminal material to the bursa copulatrix of the female. The physiological significance of the JH transfer remains unknown.Research was supported by a grant from the National Science Foundation (PCM72-01892) and Organized Research Funds from Texas A&M University.This work was done as partial fulfillment for the degree of Doctor of Philosophy.     

Juvenile hormone catabolism inManduca sexta: Homologue selectivity of catabolism and identification of a diol-phosphate conjugate as a major end product

We studied time-dependent metabolism of (10R)-[³H] juvenile hormone (JH) III and (10R, 11S)-[³H]JH I injected intoManduca sexta larvae; the hormones are metabolized to polar metabolites, expecially the JH acid-diol, and an unknown. Products were analyzed using a reversed-phase liquid chromatography assay. (10R)-JH III is metabolized much more rapidly than (10R, 11S)-[³H]JH I, whether injected seperately or as a mixture of hormones. The unknown metabolites of JH I and JH III were identified as phosphate conjugates of JH I and JH III diol by tandem mass spectral analysis of isolated samples. The phosphate conjugate of JH I diol is the principle end product of JH I metabolism.     

In vitro synthetic activity of the juvenile ovotestis ofHelix aspersa: Influence of the brain and the dorsal bodies

Summary A bioassay was developed inHelix aspersa to study the effect of known endocrine centers on the twomonth-old gonad, using organ culture. The incorporation of¹⁴C leucine and³H fucose in the juvenile gonad almost doubled over control levels, in the presence of the brain and the dorsal bodies.     

Effects of exogenous juvenile hormone I on the numbers and distribution of antennal and maxillary and labial palp sensilla of maleBlattella germanica (L.) (Dictyoptera: Blattellidae)

Summary Unlike in the female, application of exogenous juvenile hormone I to 6th-instar male nymphs does not result in the retention of nymphal characteristics on the antennae and maxillary and labial palps. JH-treatment differentially affects the numbers of sensilla on the 3 appendages of adult maleB. germanica.     

Über eine selektive Mitosehemmung und -schädigung bei jungen Ratten durch Synthalin A

Summary A single subcutaneous injection of synthalin-A does not affect the cytoplasma ofA-cells in pancreatic islets of the rat during the 1^st–5^th day of life, in contrast to adult animals. Selective action was found on mitoticA-cells: reduction of mitotic frequency to 25% of the normal rate, and pathological mitoses in the sense of the so-called primary effect. The mitoses ofB-cells, exocrine pancreatic cells and intestinal epithelia seemed to be unchanged, although the mitotic rate was higher than inA-cells.     

Titers of ecdysone, 20-hydroxyecdysone and juvenile hormone III throughout the life cycle of a hemimetabolous insect,the ovoviviparous cockroachNauphoeta cinerea

Summary Titers of ecdysone, 20-hydroxyecdysone and juvenile hormone III were measured in whole body extracts or hemolymph of embryos, first, penultimate and last stadium nymphs, and adult females ofNaupoheta cinerea. We used a gas-chromatography/mass spectrometry method for quantifying juvenile hormone and a radio-immunoassay for ecdysteroid determination. Juvenile hormone III is particularly abundant in the embryonic stage (up to 960 ng/g), at a low level in first and penultimate stadium nymphs (2–10 ng/ml) and almost absent in the last nymphal stadium; in the adult female the juvenile hormone titer rises to 180 ng/ml in hemolymph during rapid oocyte growth. The titers of ecdysone and 20-hydroxyecdysone undergo similar fluctuations in the embryonic and nymphal stages, being highest at the time of cuticle formation in the embryo and a few days before the nymphal and adult molts (around 100–200 ng/ml for exdysone and 2–4 g/ml for 20-hydroxyecdysone).Acknowledgments. We thank Mrs A. Tschan for rearing the cockroaches, Mr M. Kaltenrieder for drawing the graphs, Mr G.C. Jamieson and Mrs C. Reuter for GC/MS analyses. We are also grateful to the Swiss National Science Foundation (grant no. 3.291-0.82 to B. Lanzrein) and the United States National Science Foundation (grant no. PCM 82-08665 to D.A. Schooley) for their financial support.     

Enhancement of boll weevilAnthonomus grandis Boh. (Coleoptera: Curculionidae) pheromone biosynthesis with JH III

Summary The juvenile hormone JH III, when incorporated at 1.0 ppm in the diet of adult male boll weevils (Anthonomus grandis Boh.), increased the biosynthesis of its 4 pheromone compounds by 3 times. The biosynthesis at lower and higher levels of JH III was less. JH I was not active at any of the concentrations tested.In cooperation with the Miss. Agr. and For. Exp. Sta., Miss. State, MS 39762. Mention of a proprietary product does not necessarily imply endorsement of this product by the USDA.     

Some effects of radiation on the free amino acids of adult female Mediterranean fruit fly,Ceratitis capitata Wied

Summary Ceratitis capitata pupae, 2–3 days before adult emergence, were treated with gamma irradiation from a⁶⁰Co source. The female fruit flies were extracted and analyzed for free amino acids.     

Phosphoramidon enhances allatostatin-mediated inhibition of juvenile hormone biosynthesis in the corpora allta of the cockroach,Diploptera punctata

Use of the enkephalinase inhibitor phosphoramidon in the in vitro radiochemical assay for juvenile hormone biosynthesis enhanced allatostatin-mediated inhibition of hormone production by corpora allata of the cockroach,Diploptera punctata. Significant increases in inhibition in day 2 virgin female CA by AST 1 (at 10^–7 M) and AST 4 (10^–8–10^–7 M) were observed in the presence of phosphoramidon (10^–5M or greater). No significant increases in inhibition were seen in CA from day 6 mated females with AST 4 (10^–9–10^–7M) and phosphoramidon combined. Phosphoramidon alone had no effect on JH biosynthesis. Analysis of allatostatin content of the CA, as determined by ELISA, revealed that addition of phosphoramidon to the medium increased the endogenous allatostatin conten in CA of virgin and mated females. The similarity in primary structure between allatostatins and enkephalin-like peptides and their similar distribution makes it probable that phosphoramidon acts by preventing breakdown of allatostatins within the CA.     

In vitro inactivation of corpora allata of the bugOncopeltus fasciatus by precocene II

Summary Corpora allata fromOncopeltus fasciatus incubated in vitro in medium containing 10^–5.35 M (1 g/ml) of precocene II lose their ability to secrete juvenile hormone when reimplanted into last instar larvae.Acknowledgments. We thank Mr K. Dorn, Mrs L. Dolezal, Mrs V. Nötzli-Graf, Mr K.H. Trautmann and Mr A. Schuler for technical help, Dr W. Vogel and Dr A. Dübendorfer for valuable discussions.     

Phosphorylation of cockroach antennal polypeptides: effects of second messengers and pheromonal blend

In insect antennal extracts, Schleicher et al.¹ showed that protein kinase C (PKC) inhibitors abolish the transience of pheromone-induced rapid inositol trisphosphate responses, which suggests that pheromonal signals act on phosphorylation of specific proteins. To confirm this hypothesis, we studied the effects of second messengers and a pheromonal blend on phosphorylation of antennal proteins in the cockroachPeriplaneta americana. Proteins from adult male antennae were phosphorylated in vitro in the presence of [³²P] triphosphate, then separated by SDS-polyacrylamide gel electrophoresis. Numerous phosphopolypeptides were visualized. The presence of Ca⁺⁺/calmodulin in the incubation medium resulted in increased phosphorylation of polypeptides with molecular weights of 38, 48, 51, 54 and 58 kDa. Stimulation of PKC by addition of Ca⁺⁺ phosphatidylserine (PS)/phorbol myristate acetate (PMA) resulted in the appearance of three phosphopolypeptides of 36, 70 and 120 kDa. In the presence of cyclic adenosine monophosphate, two new major polypeptides of 46 and 42 kDa appeared; the latter polypeptide also appeared in the presence of cyclic guanosine monophosphate. Comparison with polypeptide composition of tissue from the cerci, leg, brain and fat body showed that the 36 and 48 kDa polypeptides were specific to antennae, whereas the 120 kDa polypeptide was also present in the adult brain. When antennae are subjected to pheromonal stimulation for 16 seconds prior to homogenization, in vitro phosphorylation of the 120, 70, 64 and 38 kDa polypeptides was inhibited, whereas phosphorylation of the 58, 54, 51 and 48 kDa polypeptides was strongly stimulated. It is noteworthy that a 107 kDa polypeptide was observed only after pheromonal stimulation by Ca⁺⁺/PS/PMA. Our findings suggest that Ca⁺⁺-and PKC-dependent protein phosphorylation systems play an important role in the transduction of pheromonal signals in antennae of male cockroachP. americana. We speculate that specific phosphoproteins may modulate sensitivity and signal amplification during the olfactory transduction process.     

Genotoxic evaluation of ten carcinogens in theDrosophila melanogaster wing spot test

To provide further background data on the wing spot somatic mutation and recombination assay, 10 selected carcinogens (acetamide, acrylamide, benzo(a)pyrene, cyclophosphamide, diethylstilbestrol, 4-nitroquinoline N-oxide, propyleneimine, safrole, thiourea, and o-toluidine) were tested in this assay. 72-h-old third-instar larvae, trans-heterozygous for 2 recessive wing cell markers:multiple wing hairs (mwh) andflare ³ (flr ³) were fed with 3 concentrations of each carcinogen during the rest of their development until pupation, and the genotoxic effects were measured as significant increases in the appearance of visible mutant hair clones on the adult wing blade. Our results show that 6 of the carcinogens tested produce significant increases in wing spot frequency, at least at one of the concentrations assayed. Benzo(a)pyrene, diethylstilbestrol, safrole and thiourea were the compounds that did not increase the incidence of mutant clones.     

Ecdysteroid-dependent larval-adult oviduct transformation in the milkweed bugOncopeltus fasciatus requires absence of juvenile hormone

Summary It has been tested whether juvenile hormone plays a role in the larval-adult transformation of lateral oviducts in the milkweed bug. The transformation is ecdysteroid-dependent, as was reported previously². Application of precocene or juvenile hormone III proved that the absence of juvenile hormone is required.Acknowledgments. This work was supported by a grant (Do 163/91) of the DFG. We thank Ms C. Friederichs for excellent technical support.     

Adrenal corticosteroidogenesis after removal of ventral prostate gland

Summary Removal of the ventral prostate gland in adult male rats causes an increase in adrenal weight, and stimulation of adrenal ⁵-3-hydroxysteroid dehydrogenase activity along with elevation of serum levels of corticosterone and prolactin.     

Prevention of estrogenic inhibition of adrenal 686-1686-1686-1686-2686-2686-2in rats

Summary The urinary protein _2u stimulates adrenal ⁵-3 dehydrogenase activity and prevents adrenal enlargement in estrogen-treated adult male rats.Acknowledgements. Dehydroepiandrosterone used in this study was donated by Organon(India) Ltd, Calcutta. This work received financial support from University Grants' Commission, New Delhi. The author's thanks are due to Prof. A. K. Maiti and Prof. C. Deb, Department of Physiology, Calcutta University, for their constant encouragement.     

Radiochemical assays of corpus allatum activity in adult female cockroaches following ovariectomy in the last nymphal instar

Summary Surgical removal of the ovaries from nymphalPeriplaneta americana results in lower than normal corpus allatum activity in the adult insect and an apparent absence of the manifestly cyclic pattern of juvenile hormone biosynthesis found in intact mated females. The results suggest that the presence of synchronously developing ovaries is necessary for the attainment of normal synthetic activity in the corpus allatum of this species.Acknowledgment. I thank Dr G. E. Pratt for his helpful advice and stimulating discussions on the subject.     

Extraokulare Steuerung des Farbwechsels bei Kaulquappen

Summary In tadpoles ofRana temporaria, the light threshold for the pigment dispersal of melanophores was determined. The darkening reaction of previously dark-adapted animals is not affected by removal of the lateral eyes and starts with illumination of about 0.01 lm/m². This is about 2 log units below the threshold of the direct effect of light on tailfin-melanophores inXenopus tadpoles and about 2 log units above the light threshold of the steady discharge of the exposed diencephalon in adult frogs. The finding suggests that in tadpoles the pineal organ controls the function of melanophores.