摘要:

AbstractParticulate fractions (10,000g) from pupae ofStomoxys calcitranstransfer [14C]‐mannose from GDP‐[14C]‐mannose to dolichol monophosphate and proteins. Production of the mannosyl lipid was inhibited by Mn2+, UDP, GMP, GDP, and EDTA. The insect growth regulator diflubenzuron had no effect on mannosyl transferase activity. Dolichol monophosphate and Mg2+stimulated mannosyl transferase activity. The mannosyl lipid product was identified as mannosyl‐phosphoryl‐dolichol (Man‐P‐Dol). The apparent Kmand Vmaxvalues for the formation of Man‐P‐Dol using GDP‐[14C]‐Man while holding dolichol phosphate constant were 2.4 ± 0.9 μM and 9.4 ± 2.3 pmol Man‐P‐Dol·min−1·mg−1protein, respectively. The apparent Kmand Vmaxvalues using dólichol phosphate while holding GDP‐Man constant were 2.2 ± 1.2 μM and 18.5

ISSN:0739-4462    

DOI:10.1002/arch.940010102

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

年代:1983

数据来源: WILEY

摘要:

AbstractA compound with significant insect juvenile hormone activity was isolated from the plant,Macropiper excelsum. The chemical structure was determined by spectral methods to be 1‐(3,4‐methylenedioxyphenyl)‐trans‐3‐decene(l), and confirmed by synthesis. The hormonally active substance applied topically to last (fifth)‐instar nymphs of the milkweed bug (Oncopeltus fasciatus) induced a supernumerary metamorphosis at 30 μg. Higher dose

ISSN:0739-4462    

DOI:10.1002/arch.940010103

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

年代:1983

数据来源: WILEY

摘要:

AbstractSterols from pollen collected by foraging honeybees,Apis melliferaL, at seven field sites were compared with the sterols of foraging adults and/or prepupae collected from colonies at each site. Invariably, the composition of prepupal sterols was comparable to that found in previous cage studies using chemically defined diets containing various dietary sterols: 24‐methyl‐enecholesterol was the major sterol; sitosterol and isofucosterol were present in lesser, but significant amounts; and a trace amount of cholesterol was identified in each sample. This occurred even though some of the pollen sterols contained little 24‐methylenecholesterol, sitosterol, or isofucosterol and a preponderance of certain other sterols, such as δ7‐stigmasten‐3β‐ol and δ7,24(28)‐campestadien‐3β‐ol in goldenrod and corn pollens, respectively. Thus the selective transfer and utilization of sterols in honeybees that have been demonstrated in cage studies with artificial diets were also shown to occur u

ISSN:0739-4462    

DOI:10.1002/arch.940010104

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe mechanism of action of chlordimeform on the mealworm nerve‐muscle preparation was studied with microelectrodes. Chlordimeform affected neither the mean amplitude nor the frequency of spontaneous miniature excitatory postsynaptic potentials. Extracellular focal recordings show that in the presence of 0.8 mM chlordimeform the presynaptic spike is almost unchanged, but the quantal content for evoked transmitter release is reduced. It is suggested that chlordimeform decreases the influx of calcium at the presynaptic terminal during the active phase of the nerve terminal action potential, thereby inhibiting evoked transmitter releas

ISSN:0739-4462    

DOI:10.1002/arch.940010105

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

年代:1983

数据来源: WILEY

摘要:

AbstractInsects convert ecdysone and 20‐hydroxyecdysone into their corresponding 26‐oic derivatives, named ecdysonoic acid and 20‐hydroxyecdysonoic acid respectively. The conversion takes piace in several tissues and can either be the only pathway for converting ecdysone into highly polar ecdysteroids, or coexist with various conjugating mechanisms.20‐Hydroxyecdysonoic acid was isolated fromPieris brassicaepupae as its methyl ester derivative. Its chemical structure was identified by Cl/D mass spectrometry and compared with a synthetic compound (20‐hydroxy‐25‐deoxyecdysonoic acid) chemically prepared by oxidation of inokosterone (20,26‐dihydroxy‐25‐deoxyecdysone). Natural ecdysonoic acids appear to exist as a mixture of 25R and 25S isomers.The significance of this pathway is discussed in comparison with similar reactions occuring in the metabolism of steroid horm

ISSN:0739-4462    

DOI:10.1002/arch.940010106

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe radiolabeled lectins, concanavalin A* and wheat germ agglutinin, were used to study surface properties of two insect cell lines. We also looked at the effects of tunicamycin and 20‐hydroxyecdysone on the binding of these lectins to one of the cell lines. Both UMBGE‐2 and CH‐MRRL cells bound both lectins, specifically. The CH‐MRRL cells showed an overall higher binding for the lectins than the UMBGE‐2 cells. This difference may account for some of the striking morphological difference seen between these cells. Tunicamycin and 20‐hydroxyecdysone decreased the binding of both [125I]‐Con A and [125I]‐WGA to CH‐MRRL cells. These results suggest that cell surface glycoproteins play a role in the modification of cellular morphology and in other hormone‐mediated phys

ISSN:0739-4462    

DOI:10.1002/arch.940010107

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe monooxygenase activity of fetal hepatocytes in culture shows a differential response toward juvenile hormone I and analogs. Juvenile hormone I, R‐20458, and Methoprene increase the deethyiation of 7‐ethoxyresorufin while not affecting or even inhibiting the N‐demethylation of p‐chloro‐N‐methylaniline. RO‐203600, a 1,3‐benzodioxole‐containing analog, increases both the deethylase and the N‐demethylase, whereas Hydroprene does not affect either activity. The inductive effect with juvenile hormone I is obtained with exposure periods of at least 30 min and is maximum when the concentration of the hormone is 14 μM in the medium. This amount results in the covalent binding to cellular macromolecules of 1.3 × 19−18moles/cell. The induction requires continuous protein synthesis but RNA synthesis only for a short initial period. It is concluded that juvenile hormone and mimics induce specific cytochrome P‐450 species in fetal liver cells even if the culture conditions are not optimal. The toxicological implications of these resu

ISSN:0739-4462    

DOI:10.1002/arch.940010108

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

年代:1983

数据来源: WILEY

摘要:

AbstractElectrical responses of the whole antenna (electroantennogram) and that of the single sensillum trichodeum (electrosensillogram) of male moth of the European corn borer,Ostrinia nubilalis, to their two pheromone components, (Z)‐ and (E)‐11‐tetradecenyl acetates, were recorded simultaneously. The configuration characteristics of both responses resemble each other, and demonstrate an interaction between sensilla trichodea. The typical difference in the response pattern between London (Ontario) and New York strains of this moth seems to be a property of the sensillum trich

ISSN:0739-4462    

DOI:10.1002/arch.940010109

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

年代:1983

数据来源: WILEY

摘要:

Abstract1) lontophoretic application of L‐glutamate was employed to study the distribution of glutamate receptors in the superior longitudinal (SL) muscles of the locust (Locusta migratoria) hindgut, in which spontaneous activity was inhibited using normal saline containing 5 mM MgCl2.2) Junctional glutamate potentials with a rise time of 50–100 ms (peak) and a decay time of 250–400 ms were recorded at localized sites using ejection pulses in the range 5–10 nC. Most active sites were found in interfiber clefts and were spaced at about 250–300 μm intervals. 3) Desensitization of glutamate receptors occurred using ejection frequencies>0.2 Hz. Desensitization could be irreversibly blocked using the lectin concanavalin A. 4) Depolarizing (D‐) and biphasic depolarizing/hyperpofarizing (DH ‐) extrajunctional glutamate potentials were observed using ejection pulses>15 nC. 5) δ‐Philanthotoxin (δ‐PTX) at concentrations>0.3 Uml−1inhibited junctional glutamate potentials in a dose‐dependent manner, 50% inhibition was achieved using 0.45 Uml−1δ‐PTX. 6) Subthreshold concentrations of proctolin (up to 5 × 10−10M) had no visible effect on glutamate potentials, suggesting that proctolin possibly does not act by modulating glutamate activity. 7) It is proposed that glutamate plays a transmitter role in SL muscles, while the ro

ISSN:0739-4462    

DOI:10.1002/arch.940010110

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe absence of phytosterol dealkylation in the cotton stainer bug,Dysdercus fasciatus, has been established and the major ecdysteroid in the fifth‐stage larvae identified. The demonstration that the free and esterified sterols inD fasciatusconsisted of 95–96% sitosterol and 4–5% campesterol, a similar composition to the cottonseed diet, together with the lack of conversion of [14C]sitosterol into cholesterol, establishes that phytosterol dealkylation does not occur in this insect species. The ecdysteroid titer determined by radioimmunoassay in the fifth instar ofD fasciatusshows a distinct peak at day 6, the instar lasting for 7 days. Makisterone A was purified by HPLC from insects at a time of high ecdysteroid titer and identified as a major component by both fast atom bombardment and electron impact mass spectrometry. Gas‐liquid chromatography/mass spectrometry (selected ion monitoring) confirmed the occurrence of makisterone A and revealed the presence of two unidentified compounds. One of these occurs in a similar amount to makisterone A and may be 26‐hydroxymakisterone A, whereas only a minute amount of the other compound, which may be 20‐deoxymakisterone A, was present; further identification of the latter compounds is necessary. C27ecdysteroids (eg, ecdysone and 20‐hydroxyecdysone) and C29ecdysteroids (eg, podecdysone A) were undetectable. The specificity of the enzymes of ecdysteroid biosynthesis

ISSN:0739-4462    

DOI:10.1002/arch.940010111

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

年代:1983

数据来源: WILEY