摘要:

AbstractIn an effort to determine the sterol precursor(s) of the 28‐carbon ecdysteroid, makisterone A, honey bee pupae (13 days post‐oviposition) were injected with radiolabeled sterols and subsequently examined for labeled ecdysteroids. High performance liquid chromatography of the pupal extracts revealed that [3H]campesterol was converted to a compound that behaved chromatographically identical to authentic makisterone A, and [14C]cholesterol was incorporated into a compound chromatographically like 20‐hydroxyecdysone. No incorporation of either 24‐[3H]methylenecholesterol or [14C]sitosterol into an ecdysteroid was observed. The neutral sterols of uninjected honey bee pupae contained 49.8% 24‐methylenecholesterol on a relative percent basis and, with three other C28and C29sterols, accounted for over 99% of the total sterol

ISSN:0739-4462    

DOI:10.1002/arch.940030502

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

年代:1986

数据来源: WILEY

摘要:

AbstractLast‐stage nymphs of the broad‐headed bug,Megalotomus quinquespinosuscontain the C28ecdysteroid makisterone A as their major ecdysteroid. No ecdysone or 20‐hydroxyecdysone was detected in whole body extracts analyzed by high performance liquid chromatography and radioimmune assay. Analyses of the neutral sterols of this phytophagous hemipteran revealed that the sterol composition of the nymphs was highly reflective of their dietary sterols. The most abundant nymphal sterols were sitosterol (46.6%), Δ7‐stigmastenol (13.8%) and spinasterol (13.4%). Cholesterol accounted for only 0.2% of the total sterols and indicates that this species is incapable of converting 24‐alkyl sterols to c

ISSN:0739-4462    

DOI:10.1002/arch.940030503

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

年代:1986

数据来源: WILEY

摘要:

AbstractInteractions of charatoxin (4‐methylthio‐1,2‐dithiolane; ChTX) and four openchain analogs as well as nereistoxin (NTX) with acetylcholine (ACh) receptors were studied using biochemical assays on theTorpedoelectric organ and honey bee brain receptors and using electrophysiological assays on the response of the cell body of the fast coxal depressor motoneuron (Df) of the cockroachPeriplaneta americanato ACh. The actions of ChTXs were complex. Except for ChTX Xl, they all potentiated the ACh‐induced current inPeriplanetaneurons, but at higher concentrations all ChTXs, except for ChTX XII, caused voltage‐dependent block of this current. All CHTXs inhibited binding of [3H]perhydrohistrionicotoxin in the presence of ACh to the highaffinity noncompetitive blocker site on theTorpedoreceptor, but all, except for ChTX XI, potentiated its binding in absence of ACh. The actions of ChTXs on the honey bee brain receptor were quite different from those on theTorpedoreceptor. They inhibited, or had no effect on, [125I]α‐bungarotoxin (α‐BGT) binding to theTorpedoreceptor, but all ChTXs, except for ChTX I, potentiated its binding to the honey bee receptor. It is suggested that the action of ChTXs on nicotinic ACh‐receptors resulted from binding to lowaffinity noncompetitive blocker site. On the other hand, NTX was more potent than ChTXs on nicotinic ACh‐receptors, and some similarities were noted between the actions of NTX onTorpedoand honey bee receptors NTX had a weak agonistlike effect in both cases and possibly bound to the ACh binding sites as well as the high‐affinity noncompetitive blocker site. Thus the mechanisms of action of ChTXs and NTX on nicotinic ACh‐receptors are different, and there are also differences in the responses to these toxins between receptors of insect central nervous system a

ISSN:0739-4462    

DOI:10.1002/arch.940030504

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

年代:1986

数据来源: WILEY

摘要:

AbstractEffects of sublethal doses ie, 2, 4, 10, and 20 ppm of cypermethrin, were studied on the sixth‐instar larvae ofTribolium castaneum(Herbst.). Of all the biochemical parameters tested, the free amino acids and cholesterol content and the activity of amylase were found to be the most sensitive components. Glutamate pyruvate transaminase activity was elevated at all doses except 2 ppm. The activities of alkaline phosphatase and glutamate oxaloacetate transaminase and glucose content were raised significantly at doses of 10 and 20 ppm. Acid phosphatase activity and the soluble protein content increased at a dose of 20 ppm. Total lipid and triglycerides, however, decreased significantly at this sublethal dose. Other biochemical parameters, such as cholinesterase and lactate dehydrogenase activities and the total protein, urea, glycogen, DNA, and RNA contents, were not significantly affected by exposure to different doses of cypermethri

ISSN:0739-4462    

DOI:10.1002/arch.940030505

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

年代:1986

数据来源: WILEY

摘要:

AbstractDuring their growth on the substitution hostGalleria mellonella, about onethird ofPseudoperichaeta nigrolineatalarvae undergo a developmental arrest in the middle of the second stage. To assess the extent of endocrine involvement, juvenile hormone (JH) and ecdysteroid (ECD) determinations by radioimmunoassays were made both onG. mellonellaandP. nigrolineatathroughout the larval development of this parasitoid. The transfer ofG. mellonellalarvae from the usual rearing temperature (27.5°C) to that required for infestation (21°C) significantly affects hormone titers: the JH level increases 10 to 20 times, while the ECD level becomes 10 times lower. The JH levels are lower in hosts with parasitoids in developmental arrest than in those withP. nigrolineatain continuous growth, but the high variability makes it seem unlikely that the titer of this hormone is critical in regulating development of the parasitoid. ECD levels are depressed in the hosts with parasitoids in developmental arrest and are increased when the parasitoids resume growth. Therefore, we propose that the main cause of the developmental arrest ofP. nigrolineatais the low ECD levels characterizing someG. mellonellalarvae for which the transfer to 21°C has induced some physiological disturbanc

ISSN:0739-4462    

DOI:10.1002/arch.940030506

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

年代:1986

数据来源: WILEY

摘要:

AbstractUnilateral section of the nervi corporis allati I (NCA‐1) of isolated, starved, adult, virginPeriplaneta americanadisinhibited oocyte growth during a specific period following their adult emergence. The effect required that the corpus allatum (CA) be free of NCA‐1 innervation for 4 days beyond the time the females were 7–8 days old. The onset of this sensitive period corresponds to when most isolated, starved virgins become sexually receptive. The results suggest that NCA‐1 inhibition of CA activity, initiated about 7 days, is relieved by mating. When done on sexually receptive, starved virgins, unilateral NCA‐1 section was as effective as insemination for stimulating growth and chorionation of the first generation of oocytes. Neural inhibition of juvenile hormone (JH) secretion by the CA may also explain diminished production of oocytes by isolated, fed virgins, for during 30 days following unilateral NCA‐1 section they produced 2.6 to 5 times more oothecae than did controls with a single CA removed or after the sham operation. The number of oothecae deposited by fed virgins was similarly increased after bilateral NCA‐1 section, but to a lesser extent than when the operation was done on fed, inseminated females of the same age.Specificity of the response of the CA to denervation was substantiated by experiments in which the CA were extirpated and reimplanted, by topically applying C16JH, and by experiments in which the nervus corporis cardiaci 1 and 2 on the right or left side

ISSN:0739-4462    

DOI:10.1002/arch.940030507

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe uric acid contents in larvae, pupae, and culture media were studied during larval and pupal development in three genotypes ofDrosophila melanogasterreared in both crowded and noncrowded conditions. The uric acid content and the response of genotypes in media supplemented with 10 and 15 mg/ml of uric acid were correlated with the outcome obtained in conditioned media. In addition, the behavior of genotypes in conditioned media is explained in terms of the physicochemical properties of the conditioned media, which include uric acid content, the amount of food ingested, the degree of free water, the physical disturbance within the cultures, and the particular response of each genotype to uric acid.

ISSN:0739-4462    

DOI:10.1002/arch.940030508

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.940030509

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.940030501

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

年代:1986

数据来源: WILEY