摘要:

AbstractVitellin, the major egg yolk protein, and vitellogenin, the hemolymph precursor of egg yolk protein, have been purified to apparent homogeneity from the mosquitoAedes aegypti. The purification procedure included chromatography on ion exchange, hydrophobic, and gel filtration columns. Vitellin and vitellogenin have a similar molecular weight (Mr300,000) on gel filtration columns. However, the molecular weights of vitellin and vitellogenin, as determined from SDS electrophoresis, were 393,000 and 337,000, respectively.Vitellin in sodium dodecyl sulfate released six subunits of molecular weight 116,000, 83,000, 75,000, 54,000, 36,000, and 29,000, whereas vitellogenin released only three subunits (155,000, 120,000, and 62,000). The average molecular weights of vitellin and vitellogenin after gel filtration and SDS electrophoresis were 346,000 and 318,000, respectively.Vitellin has a high content of aspartic acid and glutamic acid, and a low content of histidine, methionine, cysteine, and tryptophan. Vitellin also contains 0.9% mol of glucosamine and no galactosamine. The isoelectric points of vitellin and vitellogenin are at pH 6.4 and 6.3, respectively.Aedes aegyptifat bodies incubated for short intervals in tissue culture medium in the presence of [3H]valine showed incorporation by radio‐immunoprecipitation and SDS electrophoresis into three primary vitellogenin polypeptides of molecular weights (± SEM) 156,000 ± 4,000, 114,000 ± 5,000, and 62,000 ± 400 inside the fat body and 162,000 ± 3,000, 118,200 ± 2,000, and 63,000 ± 300 in the medium. These results suggest that the molecular weight of vitellogenin synthesized inside the fat body (Mr332,000) remains unchanged when secreted into the hemolymph (Mr343,000). The three vitellogenin subunits are processed by the ovary into six subunits which are then deposited in the yolk granules as

ISSN:0739-4462    

DOI:10.1002/arch.940040202

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

年代:1987

数据来源: WILEY

摘要:

AbstractNewly emerged flies go through a stereotypic behavioral pattern of walking, grooming, abdomen contraction (pulsing), and active uptake of air (pumping). These behavioral activities can be readily distinguished on the basis of hemolymph pressure changes. Wild‐type flies and aunicornmutant that fails to properly retract its ptilinum show identical patterns of posteclosion activity. However, a portion of theunicornsdo not fully expand their wings and abdomen. Such flies are missing only the pumping component of the normal behavioral repertory, thus implying that pulsing and pumping are independently controlle

ISSN:0739-4462    

DOI:10.1002/arch.940040203

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

年代:1987

数据来源: WILEY

摘要:

AbstractFreshly ecdysed‐third instar larvae and adult females of the seed bugOxycarenus Iavateraewere treated with diethyl maleate (1 or 10 μg/specimen, topically applied), a commonly used depletor of glutathione levels, prior to the application of model precocenes (P1, P2, and EP2; 1–10 μg/specimen, topically applied). The combined treatment resulted in a significant increase of the characteristic antijuvenile hormone effects elicited by the above allatocidins, namely, induction of precocious metamorphosis in larvae and inhibition of ovarian development in adult females. These results, which indicated that diethyl maleate exerted a definite synergistic action, constitute the first example of a synergism strategy to the improvement of precocene act

ISSN:0739-4462    

DOI:10.1002/arch.940040204

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

年代:1987

数据来源: WILEY

摘要:

AbstractStarvation, chilling, and injury of last instarGalleria mellonellalarvae typically elicit extra larval molts or a delay in pupation. The primary sites of action and the nature of the signals by which these treatments affect development are not known. However, since the connections of the brain to the nerve cord are crucial for the effects of starvation and chilling, these signals apparently affect the brain‐centered program of developmental regulation via the nerve cord. Chilling, and occasionally starvation, cause extra larval molts in last instar larvae treated prior to the nervous inhibition of their corpora allata; release of a cerebral allatotropin, which stimulates the production of juvenile hormone, appears to be involved in this effect. After this time, a delay in pupation is the principal effect of starvation and chilling, and is apparently due to a temporal inhibition of the release of the prothoracicotropic hormone. Chilling also appears to inhibit unstimulated ecdysteroid production by the prothoracic glands.The effect of injury is not mediated by the nerve cord, but appears to involve an inhibitory humoral factor that affects either the brain or the prothoracic glands themselves. Injury also stimulates juvenile hormone production, an effect which is enhanced when the brain is separated from the nerve cord and which is evidenced by a delay of ecdysis and the occasional retention of some larval features in the ecdysed insects.None of the effects of these various treatments on the brain and the endocrine glands persist when the brains or glands are implanted into untreated host

ISSN:0739-4462    

DOI:10.1002/arch.940040205

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

年代:1987

数据来源: WILEY

摘要:

AbstractExposing third instar larvae of the waspBracon hebetorto triethylamine (TEA) results in malformed antennae in eclosing adults. The purpose of this research was to examine the effects of TEA at the cellular level. Rate of growth of treated antennal buds (56–76 h) and mean size (76–96 h) were significantly reduced. Internal pH was elevated for 5 h after TEA exposure. Cell size remained constant except in treated buds from 76 to 96 h, when diameter was reduced. The mean mitotic index (MI) was reduced and a normal peak at 72–76 h was eliminated. Cell death (DI) increased. Increased DI and decreased MI from 0 to 5 hours after exposure are attributed to increased pH. TEA can form reactive alkylating intermediates, and loss of the MI peak 12 h after exposure accompanied by increased DI may be due to alkylation. It is concluded that the reduced number of segments is due to an overall reduction in total number of cells. Abnormal segmentation may involve alkylation induced somatic muta

ISSN:0739-4462    

DOI:10.1002/arch.940040206

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

年代:1987

数据来源: WILEY

摘要:

AbstractEcdysone metabolism inPieris brassicaeduring the feeding last larval stage was investigated by using3H‐labeled ecdysteroid injections followed by high‐performance liquid chromatographic (HPLCAbbreviations: 3DE = 3‐dehydroecdysone; 3D20E = 3‐dehydro‐20‐hydroxyecdysone; 2026E = 20,26‐dihydroxyecdysone; E = ecdysone; Eoic = ecdysonoic acid; 2026E′ = 3‐epi‐20,26‐dihydroxyecdysone; E′ = 3‐epiecdysone; E′oic = 3‐epiecdysonoic acid; E′8P = 3‐epiecdysone 3‐phosphate; 20E′ = 3‐epi‐20‐hydroxyecdysone; 20E′3P = 3‐epi‐20‐hydroxyecdysone 3‐phosphate; FT = Fourier transform; HPLC = high‐performance liquid chromatography; 20E = 20‐hydroxyecdysone; 20Eoic = 20‐hydroxyecdysonoic acid; NMR = nuclear magnetic resonance; NP‐HPLC = normal phase HPLC; RP‐HPLC = reverse phase HPLC; TFA = trifluoroacetic acid; Tris = tris(hydroxymethyl)‐aminomethane.) analysis of metabolites. Metabolites were generally identified by comigration with available references in different HPLC systems. Analysis of compounds for which no reference was available required a large‐scale preparation and purification for their identification by1H nuclear magnetic resonance spectrometry.The metabolic reactions affect the ecdysone molecule at C‐3, C‐20, and C‐26, leading to molecules which are modified at one, two, or three of these positions. At C‐20, hydroxylation leads to 20‐hydroxyecdysteroids. At C‐26, hydroxylation leads to 26‐hydroxyecdysteroids which can be further converted into 26‐oic derivatives (ecdysonoic acids) by oxidation. At C‐3, there are several possibilities: there may be oxidation into 3‐dehydroecdysteroids, or epimerization possibly followed by phosphate conjugation.Thus, injected 20‐hydroxyecdysone was converted principally into 20‐hydroxyecdysonoic acid, 3‐dehydro‐20‐hydroxyecdysone, and 3‐epi‐20‐hydroxyecdysone 3‐phosphate. Labell

ISSN:0739-4462    

DOI:10.1002/arch.940040207

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

年代:1987

数据来源: WILEY

摘要:

AbstractThe influence of starvation on carbohydrate metabolism in fifth instar larvae ofManduca sextawas studied. The percentage of active fat body glycogen phosphorylase increased from 10% to approximately 50% within 3 h of starvation; afterward the enzyme was slowly inactivated. The increase of phosphorylase activity might have been caused by a peptide(s) from the CC. The amount of fat body glycogen in starved animals decreased over 24 h by approximately 20 mg. The released glucose molecules seem to be converted mainly to trehalose because the hemolymph trehalose concentration in starved animals was always slightly higher than in the fed controls, and the glucose concentration decreased even when phosphorylase was activated. The chitosan content in starved larvae increased during the first 9 h of treatment to the same extent as in fed controls. It is suggested that fat body glycogen phosphorylase was activated during starvation to provide substrates for chitin synthesis and energy metabolism.

ISSN:0739-4462    

DOI:10.1002/arch.940040208

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.940040201

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

年代:1987

数据来源: WILEY