摘要:

AbstractThree bithorax alleles ofDrosophila melanogasterwere tested to determine if dietary additions of fatty acids would alter their gene expression. For thebx1allele, myristic, oleic, and linoleic acids were all effective in reducing gene expression while fatty acid supplementation was ineffective with thebx3andbx34ealleles. Forbx1the nutritionally sensitive period was found to occur in the first 48 h of larval life.

ISSN:0739-4462    

DOI:10.1002/arch.940010303

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

年代:1983

数据来源: WILEY

摘要:

AbstractA phenoloxidase has been extracted, purified, and characterized from cuticle of last‐instar larvae of the red‐humped oakworm,Symmerista cannicosta. It is a typical tyrosinase (EC 1.10.3.1., o‐diphenol:O2oxidoreductase), active toward o‐diphenols but not p‐diphenols, inhibited by thiourea and phenylthiourea, with a pH optimum between 6.0 and 7.2. In these respects it resembles enzyme A ofC. vicina, one of the few species from which this presumed wound healing enzyme has been purified and characterized.Hydrolysis of either exuviae or intact cuticle from last instar larvae yielded a number of ketocatechols of which the most abundant, 2‐hydroxy, 3′,4′‐dihydroxyacetophenone, represented 2.9% of the dry weight of head capsule exuviae, 0.3% of exuviae from the remainder of the body, and 4.6% of the dry weight of head capsule cuticle from previously frozen intact larvae. Differences in the type and amount of ketocatechol recovered from these cutic

ISSN:0739-4462    

DOI:10.1002/arch.940010304

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

年代:1983

数据来源: WILEY

摘要:

AbstractCells from the continuous MRRL‐CH line derived from embryos of the tobacco hornworm synthesized chitin. Digestion of the washed pellet from [14C]‐N‐acetylglucosamine‐labeled cells by chitinase yielded a water‐soluble labeled compound. The lyophilized residue from the supernatant of the chitin digestion was analyzed by gas‐liquid chromatography as its trimethylsilyl derivative. The major component cochromatographed with derivitized chitobiose. The presence of chitobiose was confirmed by gas chro‐matography‐mass spectrometry. The synthesis of chitin by this cell line is inhibited b

ISSN:0739-4462    

DOI:10.1002/arch.940010305

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe effects of various pharmacological agents on neurally evoked contractions of the visceral muscles of the oviduct of Locusta migratoria have been examined. The pentapeptide, proctolin, at low concentrations (10−11M−10−10M), induced an increase in the amplitude of neurally evoked contractions and basal tonus, and induced the appearance and increased the frequency of myogenic contractions. Glutamate, at 10−4M, produced a small transient contraction which in some preparations was accompanied by a reduction in amplitude of neurally evoked contractions. Octopamine, at 10−6M, reduced the amplitude of neurally evoked contractions and also resulted in a relaxation of the muscles. The octopaminergic effects were inhibited by the α‐aminergic antagonist phentolamine. Neurally evoked contractions were unaffected by dopamine, 5‐HT or the acetylcholine receptor antagonists atropine and hexamethonium. Acetylcholine increased the amplitude of neurally evoked contractions, but only at the high concentration of 10−3M.The possible role of proctolin and glutamate as excitatory neuro‐transmitters and the inhibitory action of octop

ISSN:0739-4462    

DOI:10.1002/arch.940010306

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

年代:1983

数据来源: WILEY

摘要:

AbstractWild‐type Drosophila melanogaster were axenically raised on a completely synthetic fatty acid‐free diet for at least ten consecutive generations, confirming that these insects do not require dietary polyunsaturated fatty acids. Capillary column gas‐chromatographic analysis of lipids extracted from adults reared on yeast medium showed a peak which cochromatographed with linoleic acid, representing about 1.2% and 0.15% of all fatty acids in phospholipids and triacylglycerols, respectively. In flies reared on the synthetic diet for one generation or for five or more generations, the linoleic acid peak was still present but in about tenfold lower proportions of total fatty acids. This was true of both phospholipid and triglyceride frac

ISSN:0739-4462    

DOI:10.1002/arch.940010307

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

年代:1983

数据来源: WILEY

摘要:

AbstractTreatment of CH‐MRRL cells with either 20‐hydroxyecdysone or tunicamycin resulted in a decrease in the incorporation of labeled sugars into glycoproteins. This change appears to be largely quantitative, as few qualitative changes in protein bands were apparent as determined by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis. Tunicamycin caused a greater change in the amount of labeled sugar incorporated into specific glycoproteins than did 20‐hydroxyecdysone. This was more apparent in [14C]‐mannose‐labeled than in [14C]‐N‐acetylglucosamine‐labeled glycoproteins. Both compounds caused changes in cell surface glycoproteins. These changes are discussed in relation to previous work on binding of lectins to the cell surface and on the mode of acti

ISSN:0739-4462    

DOI:10.1002/arch.940010308

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

年代:1983

数据来源: WILEY

摘要:

AbstractChemical inhibitors were used as probes of mitochondrial ATPase to determine the site of action of DDT on oligomycin‐sensitive mitochondrial ATPase (OS‐ATPase) using whole mitochondria isolated from red coxal muscle of the American cockroach. Several plotting procedures were employed to delineate the form of inhibition. Relative potency and joint action were used to detect similar action, synergism, and antagonism between DDT and the inhibitory probes DCCD, Nbf‐CI, and oligomycin. DDT demonstrated not (strictly) competitive kinetics and may be acting as an uncompetitive inhibitor. DDT and DCCD produced similar additive action. At limiting concentrations of DCCD, inhibition was reduced in the presence of DDT. Effects shown by oligomycin were not altered by DDT. DDT enhanced the effects of Nbf‐CI. These interactions, together with the demonstration of not (strictly) competitive kinetics, indicate that DDT may be acting on the membrane sector as an allosteric m

ISSN:0739-4462    

DOI:10.1002/arch.940010309

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

年代:1983

数据来源: WILEY

摘要:

AbstractHeliothis zea was reared on artificial diets containing Δ5‐sterols (cholesterol, campesterol, or sitosterol), Δ7‐sterols (lathosterol, epifungisterol, or spinasterol), or Δ0‐sterols (cholestanol, epicoprostanol, campestanol, or sitostanol) in order to determine how different dietary sterols affect the type of sterols present in the tissues of the late‐sixth‐instar larva. Although all of the dietary sterols (except epicoprostanol) supported the growth of the larvae, not all of the sterols were metabolized to the same end products. In each case, at least 80% of the sterols in the tissues of the larvae retained the same nucleus as that of the dietary sterol, indicating thatH. zeacarries out very little metabolism of ring B of Δ5‐, Δ7‐, and Δ0‐sterols. The larvae dealkylated the Δ5‐, Δ7‐, and Δ0‐alkylsterols to 24‐desalkylsterols, but a greater percentage of the Δ5‐alkylsterols were metabolized in this manner. The sterols present as free sterols in the larva were also present as esterifed sterols which accounted for 2–4% of the total sterols. Therefore, the sterol composition of the tissues ofH. zeacan be a

ISSN:0739-4462    

DOI:10.1002/arch.940010310

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

年代:1983

数据来源: WILEY

摘要:

AbstractThis paper provides answers to the questions which of the toxins present in the venom of the waspPhilanthus triangulummay be responsible for the previously reported blockage of transmission through the sixth abdominal ganglion of the cockroach, and whether this may occur by block of synaptic transmission or by affecting axonal exitability. In current clamp experiments the crude venom induces a slight depolarization of the membrane of the giant axon from the sixth abdominal ganglion of the cockroach and a small and irreversible decrease in the amplitude of the action potential. These marginal effects are not seen with relatively high concentrations of the philanthotoxins β‐PTX and δ‐PTX. It appears that neither the crude venom nor the toxins significantly affect the excitability of the cockroach giant axon. At a concentration of 20 μg ml−1δ‐PTX causes a slowly reversible block of synaptic transmission from the cercal nerve XI to a giant interneuron without any change in resting membrane potential, whereas β‐PTX is inactive. Iontophoretically evoked acetylcholine potentials of the giant neuron are more sensitive to δ‐PTX than excitatory postsynaptic potentials. This suggests that the toxin acts on the post

ISSN:0739-4462    

DOI:10.1002/arch.940010311

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

年代:1983

数据来源: WILEY

摘要:

AbstractNo Absbract.

ISSN:0739-4462    

DOI:10.1002/arch.940010312

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

年代:1983

数据来源: WILEY