摘要:

AbstractChanges in activity of the corpora allata (CA) during larval‐pupal‐adult development of the tobacco hornwormManduca sextawere studied by transplantation assays, measurements of in vitro juvenile hormone (JH) and JH acid synthesis, and determination of JH acid methyltransferase (JHAMT) and 3‐hydroxy‐3‐methylglutaryl coenzyme A (HMG‐CoA) reductase activities. The data from these assays demonstrate that the CA cease to secrete JH by day 4 of the last larval instar (wandering stage). With regard to JH synthesis, they remain inactive throughout the prepupal, pupal, and most of the pharate adult periods. CA of females, but not of males, resume JH synthesis shortly before eclosion. The biochemical basis of the inactivation process is the loss of JHAMT activity. However, prepupal CA produce JH acids, as shown by enzyme and in vitro assays. Pupal and pharate adult CA do not synthesize JH acids although levels of HMG‐CoA reductase activity seem to remain relatively high. Radiolabeled JH was recovered from hemolymph of allatectomized prepupae that had been injected with radiolabeled JH acid. These results provide further evidence that certain peripheral tissues (eg, imaginal discs) convert JH acid secreted by the prepupal CA to JH and, thus, that JH acid is a prohormone in the prepupal period. The CA change from hormone secretion to prohormone secretion during larval‐prepupal transformation, a unique functional alteration in an

ISSN:0739-4462    

DOI:10.1002/arch.940030402

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe binding of [N‐methyl‐3H]scopolamine to a cockroach nerve cord preparation has been investigated. Specific [N‐methyl‐3H]scopolamine binding was found to be saturable and of high affinity (Kd= 13.9 nM). Muscarinic ligands were found to displace [N‐methyl‐3H]scopolamine binding more effectively than nicotinic ligands. The distribution of these [N‐methyl‐3H]scopolamine binding sites was examined in the metathoracic ganglion at the light microscope level by autoradiographical techniques. Specific binding was found to be localized to distinct regions of the neuropile. This pattern showed certain similarities to that seen when the ganglion was stained for acetylcholinesterase, suggesting a functional role for these insect muscarinic acetylch

ISSN:0739-4462    

DOI:10.1002/arch.940030403

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

年代:1986

数据来源: WILEY

摘要:

AbstractLarvae from two populations ofHeliothis zeawere reared on artificial diets containing various sterols, which supported suboptimal growth, and their tissue sterols were characterized in order to determine how these dietary sterols are utilized by this insect. The sterols studied included Δ5,7‐sterols (7‐dehydrocholesterol or ergosterol), Δ8‐sterols (lanosterol and/or 24‐dihydrolanosterol), and a Δ5‐sterol (4,4‐dimethylcholesterol). Although larvae did not develop on 4,4‐dimethylcholesterol, those fed primarily Δ8‐4,4,14‐trimethylsterols developed to the third instar. When the latter sterols were spared with cholesterol, the larvae reached the sixth instar and contained 4,4,14‐trimethylsterols as well as cholesterol in their tissues. When larvae were fed 7‐dehydrocholesterol,<1% of the larvae from one population developed to the sixth instar and these larvae contained 7‐dehydrocholesterol as their principal sterol. The other larvae successfully completed their larval stage when they were transferred from the diet containing 7‐dehydrocholesterol (or no sterol) to a diet containing cholesterol within at least 9 days. The sterol composition of larvae transferred from a diet containing cholesterol to a diet containing 7‐dehydrocholesterol, after they had reached 60% of their final weight, was 54% cholesterol and 46% 7‐dehydrocholesterol. The major sterol isolated from the tissues of the larvae fed ergosterol was also 7‐dehydrocholesterol. Therefore, although the larva ofH.zea can dealkylate and saturate the side chain of the Δ5,7,22‐24β‐methylsterol, it carries out little metabolism of the B ring of the nucleus. These studies demonstrate that, when Δ5,7‐ or Δ8‐sterols are the principal sterols in the diet ofH. zea, they are absorbed and incorporated into its tissues, although they slow the rate of growth an

ISSN:0739-4462    

DOI:10.1002/arch.940030404

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe mitochondrial proteins synthesized by spermatogenic cells fromHeliothis virescens, H. subflexa, and their male‐sterile backcross progeny were analyzed by using two‐dimensional gel electrophoresis. This subset of total cellular proteins was defined by using a combination of cellular fractionation techniques and pulse‐labeling in the presence of antibiotics. Mitochondrial morphology was also evaluated in cells from fertile and sterile testes by using the laser dye rhodamine 123. These studies revealed that while abnormal mitochondrial structures are apparent in sperm from backcross moths, neither protein synthesis nor import into the organelle was affected in these individuals. Two mitochondrial proteins exhibiting charge variation between the two parental hybridizing species have been identified, and these results are discussed within the context of a hypothesis developed to account for the sterility pheno

ISSN:0739-4462    

DOI:10.1002/arch.940030405

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

年代:1986

数据来源: WILEY

摘要:

AbstractTrehalose, the major blood sugar ofPhormia regina, is present within its tissues in an amount exceeding that in the total blood volume. A major part of the reserve is found in the abdominal fat body. An investigation of trehalose regulation, pursued with the use of a trehalose tolerance test, indicates that within a period of 4 h the adult fly can remove from its blood amounts of this sugar in excess of twice its normal level. The surplus is dealt with in an as yet unknown way, being either sequestered in the tissues (not as trehalose or glucose), metabolized, or excreted in a form other than trehalose or glucose. The process is regulated by the head, and a link between the body and the head must be maintained throughout the entire period of activity.

ISSN:0739-4462    

DOI:10.1002/arch.940030406

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

年代:1986

数据来源: WILEY

摘要:

AbstractCuticular alkanes obtained from larvae and adults of six species of tephritid fruit flies,Anastrepha ludens, A. suspensa, Ceratitis capitata, C. rosa, Dacus cucurbitae, andD. dorsaliswere analyzed by gas chromatography. The same four major alkanes were shown to be present by capillary GC‐mass spectra in allAnastrephaandCeratitislarvae. Profiles were obtained from individual larvae and adult specimens that showed statistical differences between species, whereas profiles of conspecific life forms including pupae ofA. suspensafrom different locations showed some similarities. Sexual dimorphism was not observed in alkanes extracted from adults. A novel series of alkadienes was found in allAnastrephaandCeratitisbut not inDacu

ISSN:0739-4462    

DOI:10.1002/arch.940030407

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

年代:1986

数据来源: WILEY

ISSN:0739-4462    

DOI:10.1002/arch.940030408

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

年代:1986

数据来源: WILEY

ISSN:0739-4462    

DOI:10.1002/arch.940030401

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

年代:1986

数据来源: WILEY