摘要:

AbstractAn ecdysteroid RIA was used to determine the ecdysteroid titer in developing embryos ofDysdercus fasciatusand revealed that peak titer occurred approximately 120 h post‐oviposition. Analysis of neutral sterols at this time indicated sitosterol to be the predominant neutral sterol with lesser amounts of campesterol. Embryonic sterols were highly reflective of the sterols found in the cotton seed diet upon which previous generations of the bugs had fed. Analysis of the embryonic extract for ecdysteroids indicated the presence of both makisterone A and the 29‐carbon ecdysteroid makisterone C. Isolation of these compounds was accomplished by reversed‐phase and silica HPLC in conjunction with RIA, and the identification of both compounds was confirmed by mass spectrometry. No ecdysone or 20‐hydroxyecdysone was detected in the embryonic

ISSN:0739-4462    

DOI:10.1002/arch.940180202

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe biosythesis of 2‐methylheptadecane was investigated in three moth species,Holomelina lamae,H. immaculata, andH. aurantiaca, all of which use this hydrocarbon as the principal component of their volatile sex pheromone. Following injection into adult females, deuterium‐labeled leucine and isovaleric acid were readily incorporated into pheromone but valine and isobutyric acids were not. Radiolabeled acetate and malonic acid also gave good incorporation into pheromone as did 13‐methyltetradecanoic acid and 15‐methlhexadecanoic acid. These findings support a biosynthesis pathway whereby leucine is converted to isovaleric acid, which serves as the methly branch donor and chain initiator; malonic acid donates seven additional 2 carbon units to from 17‐methloctadecanoic acid, which is then deccarboxylated to produce the odd‐carbon chain hydrocarbon pheromone. Methyl‐branched fatty acids were detected in only small amounts or were absent in pheromone gland extracts, and among the different glandular lipid classes, labeled leucine and acetate were only incorporated into hydrocarbons. These findings suggest that onceinitiated, biosynthesis of the pheromone proceeds rapidly with little or no accu mulation of intermediates and/or that the pheromone or some long‐chain intermediate is biosynthesized elsewhere in the insect and transport

ISSN:0739-4462    

DOI:10.1002/arch.940180203

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

年代:1991

数据来源: WILEY

摘要:

AbstractAlthough numerous insect cell lines have been developed over the past three decades, few of these have been from the order Hymenoptera. This report describes two new continuous cell lines from trichogrammid wasps. The extremely small size of these insects has made physiological and biochemical studies difficult. Now, with the development of the cell lines, a limitless supply of biologically active material is available for a wide variety of basic biological studies. TheTrichogramma confusumandT. exiguumcell lines (designated IPLB‐Tcon1 and IPLB‐Tex2) were characterized by chromosome and isozymes techniques. Evidence of their utility is shown by morphological response to the developmental hormone, 20‐hydroxyecdysone. The morphological change in IPLB‐Tex2 is accompanied by an induction of highly contractile cells which indicates this cell line may be composed of myoblas

ISSN:0739-4462    

DOI:10.1002/arch.940180204

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

年代:1991

数据来源: WILEY

摘要:

AbstractGut chitin synthase was characterized and the sterols and ecdysteroids in the sugarcane rootstalk borer weevil,Diaprepes abbreviatus, were identified. An in vitro cell‐free chitin synthase assay was developed using larval gut tissues fromD. abbreviatus. Subcellular fractionation experiments showed that the majority of chitin synthase activity was located in 10,000g pellets. The gut chitin synthase requires Mg2+to be fully active: 7–8‐fold increases in activity were obtained with 10 mM Mg2+present in reaction mixture. Calcium also stimulated activity (4–5‐fold with 10 mM Ca2+), while Cu+2completely inhibited at 1 mM. Other monovalent and divalent cations had little or no effect on activity. The pH and temperature optima were 7 and 25°C, respectively. Gut chitin synthesis was activated ca. 50% by trypsin treatments. GlcNAc stimulated chitin synthase activity, but Glc, GlcN and glycerin did not. Polyoxin D, UDP, and ADP inhibited the chitin synthase reaction with I50's of 75 μM, 2.3 mM, and 3.6 mM, respectively. Nikkomycin Z was a potent inhibitor of chitin synthase (91% inhibition at 10 μM). Tunicamycin and diflubenzuron had no effect on the enzyme. The apparent Km and Vmaxfor the gut chitin synthase were, respectively, 122.5 ± 7.4 μM and 426 ± 19.7 pmol/h/mg protein utilizing UDP‐GlcNAc as the substrate. Sterol analyses indicated that cholesterol was the major dietary and larval sterol. HPLC/RIA data indicated that 20‐hydroxyecdysone was the ma

ISSN:0739-4462    

DOI:10.1002/arch.940180205

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

年代:1991

数据来源: WILEY

摘要:

AbstractA [3H]‐PBAN (pheromone biosynthesis‐activating neuropeptide) analog was synthesized, and binding of the radioligand to a specific PBAN‐antiserum was achieved. The inhibition of binding of the radioligand by unlabeled PBAN, several PBAN analogs, and other competitors was studied and a specific radioimmunoassay was developed. Using this radioimmunoassay we found PBAN‐like immunoreactivity in methanol extracts of hemolymph and neural tissues from females. Higher levels of PBAN‐like immunoreactivity in extracts of brain‐suboesophageal ganglion complexes, corpora cardiaca, thoracic ganglia, and abdominal ganglia were observed during the 4‐5th h scotophase when compared to the PBAN‐like immunoreactivity levels during the 6–11th h photophase. On the other hand, the concentrations of PBAN‐like immunoreactivity in the terminal abdominal ganglion were higher during the photophase relative to minimal levels observed during the scotophase, indicating an accumulation before the onset of pheromone production. These differences in concentrations of PBAN were also reflected in the stimulation of in vitro pheromone glands, whereby significant stimulations were obtained by scotophase and photophase brain extracts, scotophase thoracic ganglia extracts, and photophase terminal abdominal ganglia extracts. No detectable levels of PBAN were found in hemolymph extracts during t

ISSN:0739-4462    

DOI:10.1002/arch.940180206

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

年代:1991

数据来源: WILEY

ISSN:0739-4462    

DOI:10.1002/arch.940180201

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

年代:1991

数据来源: WILEY