摘要:

AbstractTissues ofLocusta migratoriaare known to contain a material which crossreacts with an antibody against arginine vasopressin (AVP), and this factor has been correlated with the diuretic hormone of this species. In this paper, we report the isolation of two AVP‐like factors from suboesophageal ganglia and thoracic ganglia ofLocusta migratoria. The less abundant, more hydrophobic of these AVP‐like factors shows diuretic activity in an assay where excretion of amaranth dye fromLocusta migratoriahemolymph is used as the scoring criterion. After extracting a total of ∼ 51,000 ganglia with an acidic solvent, the crude extract was prepurified by batch adsorption/elution from disposable reversed‐phase cartridges. The prepurified extract was then sequentially purified by reversed‐phase liquid chromatography using solvent programs of substantially differing selectivity. The more abundant factor was isolated to apparent homogeneity in three steps, while the less abundant factor required four or five steps. Use of a C4reversed‐phase column minimized losses of the minor, more hydroph

ISSN:0739-4462    

DOI:10.1002/arch.940050302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractHormonal control of ovarian development was examined inBombyx mori. The weight of the ovary increased suddenly by 3 days after pupal ecdysis, and vitellogenin could be immunologically detected in the ovary at that time. The ecdysteroid titers during pupal‐adult development, quantified by radioimmunoassay, increased from day 0 to day 2. Ovarian development was arrested for a long period in brainless pupae and isolated pupal abdomens. Injection of 20‐hydroxyecdysone into such preparations stimulated development of the ovaries, and vitellogenin could be detected in ovaries 2 days after injection. The results suggest that 20‐hydroxyecdysone acts by stimulating the growth of

ISSN:0739-4462    

DOI:10.1002/arch.940050303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractThe synthesis of juvenile hormone‐III by corpora allata of the cockroachDiploptera punctatais dependent under in vitro conditions upon a supply of exogenous methionine. Radiolabelled S‐adenosylmethionine was identified by HPLC in extracts of corpora allata incubated with either [methyl‐3H]methionine or [35S]methionine. Juvenile hormone (JH) synthesis by intact glands in vitro was inhibited by cycloleucine and selenomethionine, but this inhibition could be relieved by increasing the concentration of methionine. S‐adenosylhomocysteine or sinefungin had little or no inhibitory effect on JH synthesis by intact glands, but 5′‐deoxy‐5′‐methylthioadenosine was inhibitory. Adenosine and homocysteine synergistically inhibited JH synthesis. These results show that JH‐III synthesis by intact glands can be inhibited by interfering with the S‐adenosylmethionine‐dependent transmethylation, and suggest that the product and inhibitor of that reaction, S‐adenosyl‐homocysteine, is rapidly hydrolyzed to adenosine and homocys

ISSN:0739-4462    

DOI:10.1002/arch.940050304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractThe metabolism of succinate was examined in the houseflyMusca domesticaL. The labeled carbons from [2,3‐14C]succinate were readily incorporated into cuticular hydrocarbon and internal lipid, whereas radioactivity from [1,4‐14C]succinate was not incorporated into either fraction. Examination of the incorporation of [2,3‐14C]succinate, [1‐14C]acetate, and [U‐14C]proline into hydrocarbon by radio‐gas‐liquid chromatography showed that each substrate gave a similar labeling pattern, which suggested that succinate and proline were converted to acetyl‐CoA prior to incorporation into hydrocarbons. Carbon‐13 nuclear magnetic resonance showed that the labeled carbons from [2,3‐13C]succinate enriched carbons 1, 2, and 3 of hydrocarbons with carbon‐carbon coupling showing that carbons 2 and 3 of succinate were incorporated as an intact unit. Radio‐high‐performance liquid chromatographic analysis of [2,3‐14C]succinate metabolism by mitochondrial preparations showed that in addition to labeling fumarate, malate, and citrate, considerable radioactivity was also present in the acetate fraction. The data show that succinate was not converted to methylmalonate and did not label hydrocarbon via a methylmalonyl derivative. Malic enzyme was assayed in sonicated mitochondria prepared from the abdomens and thoraces of 1‐ and 4‐day‐old insects; higher activity was obtained with NAD+in mitochondria prepared from thoraces, whereas NADP+gave higher activity with abdomen preparations. These data document the metabolism of succinate to acetyl‐CoA and not to a methylmalonyl unit prior to incorporation into lipid in the housefly and establish the role

ISSN:0739-4462    

DOI:10.1002/arch.940050305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractThe effects of diflubenzuron (DFB) inTenebrio molitorpupae were first investigated on cuticle secretion induced by 20‐hydroxyecdysone in vitro. The sternal integuments were treated by DFB either 3 days before culture or during culture. DFB, when applied before culture, did not prevent the molting hormone from inducing a new cuticle deposition by integument explants in vitro. However, this cuticle showed several architectural alterations and a thickness reduction. When applied during the culture in the presence of 20‐hydroxyecdysone, DFB at high dose (≥ 20 μg/ml) was able to inhibit cuticle secretion, but lower doses (⩽ 10 μg/ml) resulted in epicuticle deposition. These observations confirm in vivo studies showing antagonistic effects of DFB and ecdysteroids at the level of epidermal cells.In another series of experiments, the DFB effects were analyzed without addition of exogenous molting hormone in vitro. Because it had been observed in previous studies that pupal epidermal explants ofTenebriosecrete low but significant amounts of ecdysteroids in the culture medium, this in vitro secretion was measured by radioimmunoassay after DFB treatment. It was observed that DFB, when applied either before or during culture, significantly reduced the hormonal secretion in vitro. This reduction, observed at the level of epidermal cells, could be homologous with the diminution of the endogenous ecdysteroid peak previously described after in vivo DFB treatment inTene

ISSN:0739-4462    

DOI:10.1002/arch.940050306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractUsing theGalleriaprothoracicotropic bioassay, five small neurosecretory cells occurring in each dorsolateral part of protocerebrum ofGalleria mellonellabrain were identified as prothoracicotropic hormone (PTTH) cells. It was found that the critical period for the release of PTTH from a brain implanted in neck‐ligated larva lasts up to the third day after implantation. The content of paraldehyde‐fuchsin positive neurosecretory material (NSM) in PTTH cells was determined during the penultimate and last larval instar, during pupal instar, and in starved or poststarvation fed or space‐deprived last instar larvae. Two peaks of NSM in PTTH cells were found in the penultimate instar (in freshly molted, and 76‐h‐old larvae), four peaks in the last instar larvae (in freshly molted, and in 67‐, 132‐, and 174‐h‐old larvae), and one peak in the pupal instar (in 56‐76‐h‐old pupae). It was also observed that upon starvation NSM accumulated in PTTH cells, while after 3 h of poststarvation feeding it was released. In permanent space‐deprived last instar larvae no NSM occurred in PTTH cells. In all investigated larval instars a rapid release of NSM from PTTH cells was found a few hours after molt associated with the beginning of the feeding period. The significance of the NSM content in PTTH cells is discussed in rela

ISSN:0739-4462    

DOI:10.1002/arch.940050307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

ISSN:0739-4462    

DOI:10.1002/arch.940050301

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY