摘要:

AbstractThe metabolic fates of linoleic (18:2n6) and linolenic (18:3n3) acids injected into the hemocoel of fifth instar larvae of the waxmoth,Galleria mellonella, were examined by radio‐high‐pressure liquid chromatography and radio‐gas‐liquid chromatography. In addition to undergoing β‐oxidation and incorporation into neutral and phospholipid fractions, a portion of both of these C18 fatty acids was elongated and desaturated to longer chain and more unsaturated polyenoics. Radioactivity from linoleic acid was recovered in components that coeluted with 18:3, 18:4, 20:3, and 20:4. Radioactivity from linolenic acid was recovered in an unidentified component and in components that coeluted with 18:4, 20:3, and 20:5. Labeled arachidonic and eicosapentaenoic acids injected into waxmoth larvae were converted to prostaglandins, suggesting that one aspect of the biological significance of the elongation/desaturation reactions is to generate precursors for prostaglandin bi

ISSN:0739-4462    

DOI:10.1002/arch.940060302

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

年代:1987

数据来源: WILEY

摘要:

AbstractSingle‐chloride‐channel currents were recorded from primary culturedDrosophilaneurons by means of the gigaohm‐seal patch‐clamp technique. Small inward‐going current channels were observed in excised inside‐out patches with the external face of the membrane exposed to bathing solutions devoid of K+, Na+, and Ca2+. The inward current was affected by changing the anions but not the cations bathing the cytoplasmic face of the patch. Complete replacement of CI−by glutamate eliminated the current. The current was maintained with intracellular solutions containing NO3−in place of CI−. The single‐channel conductance was estimated to be 7 ps with CI−, and 11 ps with NO3−at 10°C. Possible functions of this anion‐selective c

ISSN:0739-4462    

DOI:10.1002/arch.940060303

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

年代:1987

数据来源: WILEY

摘要:

AbstractBiochemical and kinetic properties under identical substrate and reaction conditions were obtained for an ATP‐dependent Ca2+pump and (Ca2++ Mg2+)‐ATPase in synaptosome membrane vesicles prepared from the brain of the moth,Mamestra configurata.Both the ATP‐dependent Ca2+pump and (Ca2++ Mg2+)‐ATPase had single, high‐affinity binding sites for ATP (Km= 14 and 116 μM, respectively), Ca2+free(Km= 0.13 nM and 0.072 nM, respectively), and Mg2+(Km= 1.1 mM and 0.07 mM, respectively). Both systems were relatively little affected by K+and were insensitive to ouabain, an inhibitor of (Na++ K+)‐ATPase. The results indicate that the ATP‐dependent Ca2+pump and (Ca2++ Mg2+)‐ATPase are functionally coupled in synaptic membranes and constitute a mechanism for Ca2+transport in the brain ofM. configurata.Although moth brain (Ca2++ Mg2+)‐ATPase is maximally active at nanomolar concentrations of free calcium ion, the enzyme retains at least one‐half of its maximal activity at micromolar calcium concentrations, indicating either that the enzyme has two binding sites for calcium (a high‐affinity site at nanomolar Ca2+freeand a low‐affinity site at micromolar Ca2+free), or that there are two enzymes with high and low affinity for calcium, respectively. Calcium extrusion from brain neurones ofM. configuratamay operate in a two‐stage, concentration‐dependent process in which a first stage, low‐affinity pump reduces intraneuronal calcium to a concentration at which a second stage, high

ISSN:0739-4462    

DOI:10.1002/arch.940060304

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

年代:1987

数据来源: WILEY

摘要:

Abstract1‐Citronellyl‐5‐phenyl imidazole (1,5‐CPI), 1‐citronellyl‐4‐phenyl imidazole (1,4‐CPI) and 1‐citronellyl‐2‐phenyl imidazole (1,2‐CPI) were tested as inhibitors of JH‐III biosynthesis in vitro. 1,5‐CPI was found to be most active followed by 1,2‐CPI. The least active isomer was 1,4‐CPI. Inhibition of JH biosynthesis by 1,5‐CPI resulted in no significant accumulation of the epoxidation substrate methyl farnesoate, and piperonyl butoxide, a known microsomal epoxidase inhibitor, produced only a slight increase in methyl farnesoate. Topical application of fluoromevalonolactone resulted in reduced biosynthetic capability of su

ISSN:0739-4462    

DOI:10.1002/arch.940060305

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

年代:1987

数据来源: WILEY

摘要:

AbstractJuvenile hormone III was identified in purified hemolymph extracts of adult females of the cockroachBlatella germanicaby gas chromatography‐mass spectrometry with chemical ionization and selected ion monitoring. Under these conditions, juvenile hormones I and II were not detected within the sensitivity ranges of this analytical method. For quantification purposes a 5,5‐bisdeuterated analog of juvenile hormone III was synthesized and used as an internal standard. In general, juvenile hormone III titers obtained correlated with data on oocyte growth and with hormone titers found from in vitrocorpora allataincubations along the first gonotrophic cy

ISSN:0739-4462    

DOI:10.1002/arch.940060306

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

年代:1987

数据来源: WILEY

摘要:

AbstractThe binding of [3H]mianserin to homogenates of cockroach nerve cord was investigated, using a centrifugal binding assay. Nonspecific binding was defined as binding in the presence of 0.1 μM phentolamine. Specific binding was saturable and indicated a high affinity site (KD= 39.6 nM and Bmax= 0.8 fmol μGg−1) and a low affinity site (KD= 648.9 nM and Bmax= 5.9 fmol μg−1). The binding was reduced or abolished by heat, detergents, trypsin and HgCl2. Incorporation of CaCl2or NaCl into the medium reduced binding in a dose‐dependent fashion, whereas MgCl2and NaF inhibited binding in a biphasic manner. The stable GTP analog, 5′‐guanylylimidodiphosphate, reduced the high affinity binding at 10 μM. Phentolamine, D,L‐octopamine, demethylchlordimeform (DCDM), clonidine, and D,L‐synephrine are effective displacers of [3H]mianserin‐binding, whereas dopamine, acetylcholine, serotonin (5‐HT), and histamine show poor or no displacement. The pharmacological properties of octopamine‐sensitive adenylate cyclase stimulation in cockroach nerve cord are similar to those o

ISSN:0739-4462    

DOI:10.1002/arch.940060307

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.940060301

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

年代:1987

数据来源: WILEY