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1.
Single, responding males of Nippostrongylus brasiliensis exhibited a dose-dependent movement toward a pheromone source that was derived from incubation or homogenization of female helminths in Tyrode's solution. Increases in female homogenate beyond an optimum concentration resulted in reduced male movement toward the pheromone source. Crowding of male N. brasiliensis prior to their exposure to female pheromone gradients diminished the males' response. However, crowding of females had no effect on response to the pheromone. The locomotory responses of males exposed to various mixed male and female pheromone sources reaffirmed earlier suggestions of a pheromone feedback system in which males influence the pheromone released from females.  相似文献   

2.
A change in the molecular form of alkaline phosphatase in sea urchin embryos accompanies the marked increase in activity that occurs at gastrulation. On the basis of chromatographic and electrophoretic analyses, two major classes of alkaline phosphatase are identified: early enzyme, from unfertilized eggs to mesenchyme blastula, characterized by a major peak of activity, with a Kav of 0.123 on Sephadex G-200 columns, elution from DEAE-Sephadex columns by 0.5 M NaCl, and a migration value of 0.51 (relative to bromophenol blue) after electrophoresis in 7.5% polyacrylamide gels; late enzyme, from gastrula to plutei, characterized by a Kav of 0.137, elution from DEAE-Sephadex by 0.55–0.75 M NaCl, and a migration value of 0.56. By chromatographic and electrophoretic criteria the early enzyme appears to have a slightly greater molecular volume, lower net negative charge, and more heterogeneous composition than the late enzyme. Both enzyme preparations were maximally active at a pH 9.4–9.5. Enzyme from all stages appears to be predominantly associated with cell membranes. Extracting the enzyme by treatment with n-butanol, precipitating the enzyme from the dialyzed aqueous phase with ethyl alcohol, and chromatographing the alcohol preparation on columns of sieving and anion-exchanging media resulted in a substantial purification of the enzyme from all stages.  相似文献   

3.
Ann M. Jose 《Planta》1977,134(3):287-293
Pelletable phytochrome from hypocotyl hooks of Cucurbita pepo L. seedlings has been separated into two fractions by gel filtration on Sepharose CL-2B. One fraction with a K av of 0.7 was detected only after red irradiation (in vivo or in vitro). This separated from a ribonucleoprotein fraction during gel filtration. The weak interaction with ribonucleo-protein which required magnesium (optimal at 10 mM) was overcome by high salt concentrations and prevented by ribonuclease treatment. The second phytochrome fraction was strongly associated with a high molecular weight material with a K av of less than 0.1. Low levels of this complex were detected in extracts from dark grown tissue but were increased by red irradiation of excised hooks or crude extracts. The binding of phytochrome to the high molecular weight material did not require magnesium, was unaffected by ribonuclease treatment, and was much more resistant to high salt concentrations than was the phytochrome—ribonucleoprotein association. These results suggest that the association of phytochrome with this membrane—containing fraction is not electrostatic.The separation by agarose-gel filtration offers a useful technique for the preparation of membraneassociated phytochrome for physiological studies.Abbreviations EDTA ethylenediaminetetraacetic acid - P r and Pfr phytochrome in the red and far-red absorbing forms - RNase ribonuclease - RNP ribonucleoprotein  相似文献   

4.
In the female turnip moth, Agrotis segetum, a pheromone biosynthesis activating neuropeptide (PBAN) stimulates sex pheromone biosynthesis which exhibits a daily rhythm. Here we show data supporting a circadian rhythm in PBAN release from the corpora cardiaca, which we propose regulates the endogenous rhythm in sex pheromone biosynthesis. This conclusion is drawn as the observed daily rhythm in PBAN-like immunoreactivity in the hemolymph is persistent in constant darkness and is phase-shifted by an advanced light:dark cycle. PBAN-like immunoreactivity was found in the brain, the optic lobe, the suboesophageal ganglion and in the retrocerebral complex. In each hemisphere ca. 10 immunopositive neurons were observed in the pars intercerebralis and a pair of stained somata in the dorso-lateral protocerebrum. A cluster of cells containing PBAN-like immunoreactive material was found in the tritocerebrum and three clusters of such cells were found in the SOG. Their processes reach the corpora cardiaca via nervi corporis cardiaci and the dorsal surface of the corpora allata via the nervi corporis allati.  相似文献   

5.
6.
Biosynthetically radiolabelled heparan sulphate proteoglycans have been isolated from the growth medium and the cell lysate of a human neuroblastoma cell line (CHP100). Chromatography on Sepharose CL-4B identified two heparan sulphate proteoglycans in the medium (Kav 0.220 and 0.3890, whereas in the cell lysate the major proteoglycan species were more heterogenous and of a smaller overall molecular size (Kav 0.407) than the medium-derived counterparts. Chromatography on Sepharose CL-6B of free heparan sulphate glycosaminoglycan chains showed that the majority of cell-layer-derived material heparan sulphate 2, Kav=0.509) was smaller than medium heparan sulphates (heparan sulphate 1 and heparan sulphate 2, Kav 0.230 and 0.317). Analysis of the patterns of polymer sulphation by nitrous acid treatment, gel chromatography and high-voltage electrophoresis established that in each heparan sulphate fraction there was on average 1.1 sulphate residues per disaccharide with an N:O sulphate ratio of 1.1 Heparan sulphate in the medium had a high proportion of di-O-sulphated disaccharides in regions of the chain with repeat disaccharide sequences of structure GlcA-GlcNSO3, whereas cell-associated material was enriched in di-O-sulphated tetrasaccharides of alternating sequences GlcA-GlcNAc-GlcA-GlcNSO3. The identification of several populations of heparan sulphate proteoglycans differing in molecular size and glycosaminoglycan fine structure may reflect the functional diversity of this family of macromolecules in the nervous system.  相似文献   

7.
Pheromone production in the female turnip moth, Agrotis segetum, is under the control of a brain factor. This factor was demonstrated to be a proteinaceous substance termed pheromone biosynthesis activating neuropeptide-like substance (PBAN-like substance). The sex pheromone of Swedish A. segetum includes (Z)-5-decenyl acetate, (Z)-7-dodecenyl acetate, and (Z)-9-tetradecenyl acetate as major components. Decapitation of a female decreased pheromone production significantly. Pheromone production was restored by injection of homogenates of either male or female brain-suboesophageal ganglion or the corpora cardiaca alone. Pheromonotropic activity was also found in homogenates of the female thoracic ganglion and abdominal ganglion that were obtained during scotophase. Injection of female brain and thoracic ganglion homogenates made from insects during the scotophase induced two and four times as much Z7-12:OAc, respectively, as injection with similar homogenates from photophase. As little as one-eighth female equivalent (FE) brain homogenate was sufficient to increase the amount of Z7-12:OAc. The effect of brain homogenate on pheromone titer reached its maximum after 30 min. The activity of the PBAN-like substance present in female brain extracts was not correlated to the age of the donor. Injection of hemolymph collected during either photophase or scotophase into decapitated females did not increase the pheromone titer. The target site of the PBAN-like substance was not the pheromone gland, and the ventral nerve cord was not involved in the transportation of the PBAN-like substance, which implies a mode of action different from what has been reported in other moths. Brain homogenates obtained during photophase from females of African A. segetum, Spodoptera littoralis, or Ostrinia nubilalis as well as synthetic Bombyx-PBAN also induced pheromone production in decapitated Swedish female A. segetum. © 1995 Wiley-Liss, Inc.  相似文献   

8.
The fall webworm, Hyphantria cunea Drury (Lepidoptera: Arctiidae), is a harmful polyphagous defoliator. Female moths produce the following four pheromone components in a ratio of about 5:4:10:2; (9Z,12Z)-9,12-octadecadienal (I), (9Z,12Z,15Z)-9,12,15-octadecatrienal (II), cis-9,10-epoxy-(3Z,6Z)-3,6-henicosadiene (III), and cis-9,10-epoxy-(3Z,6Z)-1,3,6-henicosatriene (IV). Although 13C-labeled linolenic acid was not converted into trienal II at the pheromone glands of H. cunea females, GC-MS analysis of an extract of the pheromone gland treated topically with 13C-labeled linolenyl alcohol showed the aldehyde incorporating the isotope. Other C18 and C19 fatty alcohols were also oxidized to the corresponding aldehydes in the pheromone gland, indicating a biosynthetic pathway of IIvia linolenyl alcohol and low substrate selectivity of the alcohol oxidase in the pheromone gland. On the other hand, epoxydiene III was expected to be produced by specific 9,10-epoxidation of the corresponding C21 trienyl hydrocarbon, which might be biosynthesized from dietary linolenic acid in oenocytes and transported to the pheromone gland. The final biosynthetic step in the pheromone gland was confirmed by an experiment using deuterated C21 triene, which was synthesized by the chain elongation of linolenic acid and LiAlD4 reduction as key reactions. When the labeled triene was administered to the female by topical application at the pheromone gland or injection into the abdomen, deuterated III was detected in a pheromone extract by GC-MS analysis. Furthermore, the substrate selectivity of epoxidase and selective incorporation by the pheromone glands were examined by treatments with mixtures of the deuterated precursor and other hydrocarbons such as C19-C23 trienyl, C21 dienyl, and C21 monoenyl hydrocarbons. The 9,10-epoxy derivative of each alkene was produced, while the epoxidation of the C21 monoene was poorer than those of the trienes and diene. The low selectivity indicated that the species-specific pheromone of the H. cunea female was mainly due to the critical formation of the precursor of each component.  相似文献   

9.
Proteoglycans of the articulating and growing zones of minimum- and maximum-contact areas of calf articular cartilage were studied. Material was extracted sequentially (0.15 m sodium acetate, 2 m CaCl2, and 4 m guanidinium chloride) in the presence of protease inhibitors. The very small proportion of material extracted by 0.15 m sodium acetate was poor in carbohydrates, but rich in serine, glycine, and glutamic acid, and had a Kav of 0.42 on Sepharose 2B. Proteoglycan extracted from the articulating zone was of smaller average hydrodynamic size (Kav of monomer, 0.42) than that from the growing zone (Kav of monomer, 0.32), but the attached chondroitin sulfate chains were of similar size. Proteoglycan prepared from the articulating area of minimum contact was chondroitin sulfate enriched (molar ratio of GalN:GlcN, 27) in comparison to that prepared from other regions of the articular cartilage (GalN:GlcN, 9–12). It is suggested that age-related maturation may be modified by physiological load or stress.  相似文献   

10.
Dumville JC  Fry SC 《Planta》2003,217(6):951-961
The aim of this work was to test the hypothesis that endogenous ascorbate, released into the apoplast by membrane permeabilisation early in fruit ripening, could promote the solubilisation and depolymerisation of polysaccharides, and thus contribute to fruit softening. In vitro, ascorbate (1 mM), especially in the presence of traces of either Cu2+ or H2O2, solubilised up to 40% of the total pectin from the alcohol-insoluble residue of mature-green tomato (Lycopersicon esculentum Mill.) fruit. Solubilisation was due to the action of ascorbate-generated hydroxyl radicals (·OH), which can cause non-enzymic scission of polysaccharides. The pectins solubilised by ascorbate in vitro were polydisperse (4–1,000 kDa), partially esterified and galactose-rich. Excised pieces of living tomato fruit released ascorbate into the medium (apoplast); the ability of different tissues to do this increased in the order pericarp < placenta < locule. In all three tissues, but especially in the locule, the ability to release ascorbate increased during ripening. The Cu content of each tissue also increased during ripening, whereas neither Fe nor Mn showed a similar trend. We suggest that progressively increasing levels of Cu and ascorbate in the fruit apoplast would lead to elevated ·OH production there and thus to non-enzymic scission of pectins during ripening. Such scission could contribute to the natural softening of the fruit. De-esterified citrus pectin was more susceptible to ascorbate-induced scission in vitro than methylesterified pectin, suggesting a possible new significance for pectin methylesterase activity in fruit ripening. In conclusion, non-enzymic mechanisms of fruit softening should be considered alongside the probable roles of hydrolases, xyloglucan endotransglucosylases and expansins.Abbreviations AIR alcohol-insoluble residue - Ara l-arabinose - DMSO dimethylsulphoxide - endo-PG endo-polygalacturonase - Gal d-galactose - GalA d-galacturonic acid - Glc d-glucose - k·OH rate constant for reaction with the hydroxyl radical - Kav elution from Sepharose column relative to the void volume (Kav=0.0) and totally included volume (Kav=1.0) - MG mature-green - PME pectin methylesterase - Rha l-rhamnose - RR red-ripe  相似文献   

11.
In response female pheromone the male gypsy moth flies a zigzagging path upwind to locate the source of odor. He determines wind direction visually. To learn more about the mechanism underlying this behavior, we studied descending interneurons with dye-filled micro-electrodes. We studied the interneuronal responses to combinations of pheromone and visual stimuli.
1.  We recorded 5 neurons whose directionally selective visual responses to wide field pattern movement were amplified by pheromone (Figs. 2–6).
2.  The activity of the above neurons was more closely correlated with the position of the moving pattern than with its velocity (Fig. 4).
3.  One neuron showed no clearly directional visual response and no response to pheromone. Yet in the presence of pheromone it showed directionally selective visual responses (Fig. 6).
4.  We recorded 4 neurons whose directionally selective visual responses were not modulated by pheromone (Fig. 7), ruling out the possibility that the effect of the pheromone was simply to raise the activity of all visual neurons.
5.  Our results suggest that female pheromone amplifies some neural pathways mediating male optomotor responses, especially the directionally selective responses to the transverse movement of the image, both below and above the animal.
  相似文献   

12.
The binding of [3H]tyrosyl-PBAN28-33NH2 to pheromone gland membranes of the moth Heliothis peltigera was investigated. The study describes the development of a pheromone biosynthesis-activating neuropeptide (PBAN) radioreceptor assay and demonstrates the presence of a putative PBAN binding site on the pheromone gland. It also describes synthesis of a radioligand and optimization of binding conditions with respect to membrane preparation, number of gland equivalents, kinetics of ligand binding and composition of the binding solution. Binding was found to be optimal when membranes were freshly prepared from frozen glands, incubated at a concentration of one gland equivalent per reaction tube in the presence of 10 mM HCO3 ions. Equilibrium of ligand binding was obtained after 20 min. Presence of other components such as NaCl, KCl or SH reagents did not have any effect on binding. Binding was found to be saturable, with a Kd of 5.73 ± 1.05 × 10−6 M and a Bmax of 1.85 ± 0.22 nmol/mg protein. Binding was effectively displaced by unlabeled PBAN1-33NH2 and PBAN28-33ΝΗ2 with a Ki of 4.3 ± 1.1 × 10−6 M and 4.9 ± 2.6 × 10−6 M, respectively. Accepted: 4 February 1999  相似文献   

13.
Endoglucanase production was carried out using in-house isolate Aspergillus terreus on rice straw under solid state fermentation. An increase of 1.25-fold endoglucanase production was obtained under optimized conditions using response surface methodology. The enzyme was purified to homogeneity by gel filtration chromatography. Its molecular weight was determined as 28.18 kDa by gel filtration and 29.13 kDa on SDS-PAGE. The enzyme displayed maximum activity at 50 °C and pH 4.8. It was stable for 240 min at 50 °C and 120 min at 60 °C but rapidly inactivated at 70 °C. The purified enzyme was specific towards carboxymethyl-cellulose but showed no activity for cellobiose or xylan. Maximum velocity (Vmax) and KM were 16.15 μmol min−1 mg−1 and 12.01 mg ml−1, respectively. AgNO3, KCl, NaCl, and MnSO4 were found to inhibit enzyme activity while CaCl2 and ZnSO4 activated the enzyme. Internal peptide mass fingerprinting analysis identified that the protein belongs to GH12 superfamily endoglucanases. External supplementation of the purified enzyme to the crude cellulase showed 38.7% increase in saccharification efficiency of the delignified rice straw compared to the crude cellulase alone. The results demonstrated that the addition of GH 12 family purified endoglucanase to the crude cellulase can efficiently convert lignocellulosic biomass to fermentable sugars.  相似文献   

14.
One of the relatively few vertebrate pheromones to be chemically identified, the female sex pheromone of the red-sided garter snake (Thamnophis sirtalis parietalis) is a series of saturated and monounsaturated methyl ketones contained within female skin lipids. During the breeding season, this pheromone is responsible for eliciting male courtship behaviors and males are able to utilize pheromonal variation to discriminate among females. While the pheromone system of the red-sided garter snake has been the subject of many studies, relatively little is known about the pheromone systems of other garter snakes. Through chemical analyses, we demonstrate that female skin lipids of the red-spotted garter snake (Thamnophis sirtalis concinnus), northwestern garter snake (Thamnophis ordinoides), and plains garter snake (Thamnophis radix) contain similar methyl ketones. The methyl ketone profiles of these snakes differ qualitatively from one another and from the methyl ketone profiles of red-sided garter snakes with differences particularly pronounced between sympatric species. Our results provide evidence that the use of methyl ketones in sexual signaling may be ubiquitous for Thamnophis species and suggest that these compounds could play a role in reproductive isolation between species in this genus.  相似文献   

15.
Males of Nauphoeta cinerea produce a volatile pheromone which attracts the female for mating. Allatectomy of males either 5 days prior to or within 12 hr following the imaginal ecdysis does not impair pheromone production, pheromone release, nor any observable aspect of mating behaviour. It is proposed that in N. cinerea, and in other cockroach species where the male releases a volatile pheromone to attract the female, pheromone production is not controlled by the corpora allata, and pheromone release is under direct motor control.  相似文献   

16.
The hypothesis that female sonic stimulus may evoke male pheromone release in a behavioural interaction analogous to the known male sonic stimulus of female pheromone release, was confirmed in Dendroctonus pseudotsugae, and also in D. brevicomis. In both species known male-produced substances collected from males stimulated by recorded female stridulation were identified by coupled gas chromatography/mass spectrometry. In a second test with D. pseudotsugae, male pheromone release during recorded female stridulation was evident in the change of male stridulation from the simple attractant chirp to the interrupted chirp, which is known to result from a medium concentration of 3,2-MCH. Also, the D. pseudotsugae male attractant chirp was synthesised with an electronic pulse generator and used to evoke pheromone release. It is concluded that the antiaggregative pheromone of this species is released by each sex at the sonic stimulus of the other sex.  相似文献   

17.
Incubation of goat testicular Leydig cells with 3,5,3′-triiodothyronine(T3) induces the generation of a proteinaceous factor (factors) which was located in the soluble supernatant fraction (100 000 × g supernatant, 100k sup) of sonicated Leydig cells. Addition of this factor to Leydig cell incubation greatly stimulated androgen release. This factor(s) was purified based on its biological properties, i.e., its addition to Leydig cell incubation augmented the release of androgen. This was designated as TIP (T3-induced protein) activity. 100 k sup prepared from Leydig cells incubated in the absence (control) or presence of T3 was gel filtrated through Sephadex G-100. 100 k sup from T3 incubate gave two protein peaks, P-I and P-II, control 100 k sup had similar nature of P-I, but P-II was not well marked. Incubation in the presence of [14C]leucine clearly showed TCA precipitable radioactivity only in the P-II region of T3 incubate. 5 μg of P-II protein stimulated androgen release from Leydig cells (1 · 106 cells/well) to more than 5-fold as compared to control. P-II protein was further purifies by FPLC Mono-Q column chromatography where one unadsorbed (MQ-I) and two adsorbed(MQ-II and MQ-III) protein peaks could be detected. MQ-II, which was eluted with 0.20 M NaCl gradient, demonstrated strong TIP activity (2 μg protein released 4.8-fold more androgen as compared to control). MQ-II was passed through FPLC Superose-6 column where it gave two peaks and Peak-I(SP-I) showed strong TIP activity (2 μg protein stimulated a 6-fold increase in androgen release as compared to control). Polyacrylamide gel electrophoresis (PAGE) indicated SP-I to be a homogeneous protein and SDS-PAGE demonstrated it to be a 52 kDa monomer protein. Results show that T3 induces the synthesis of a 52 kDa protein in testicular Leydig cells which in turn causes stimulation of androgen release suggesting this protein to be a novel mediator of T3 function in Leydig cells.  相似文献   

18.
19.
The female sex pheromone of Rhizoglyphus setosus Manson (Astigmata: Acaridae) was identified as S-isorobinal (4S-4-isopropenyl-3-oxo-1-cyclohexene-1-carboxyaldehyde), which stimulated males sexually and enhanced the frequency of the male’s tapping and mounting behavior. Although the female hexane extract indicated no sign of sex pheromone activity against tested males, possibly due to the presence of the alarm pheromone neryl formate, an SiO2 column fraction containing isorobinal elicited sex pheromone activity at a dose of one female equivalent. The stereochemistry of natural isorobinal was identified as S by an HPLC using a chiral column. Both S- and R-isorobinals exhibited maximum activity at the same dose of 1 and 10 ng with a convex dose–response relationship. Amounts of S-isorobinal were determined to be 11.7 ± 1.0 ng per female and 6.4 ± 1.3 ng per male by GLC. This is the second example of two pheromones (the alarm pheromone neryl formate, and the sex pheromone S-isorobinal) demonstrated to be components of the same opisthonotal gland secretion.  相似文献   

20.
A Ca2+-dependent cyclic nucleotide phosphodiesterase has been partially purified from extracts of porcine brain by column chromatography on Sepharose 6 B containing covalently linked protamine residues, ammonium sulfate salt fractionation, and ECTEOLA-cellulose column chromatography. The resultant preparation contained a single form of cyclic nucleotide phosphodiesterase activity by the criteria of isoelectric focusing, gel filtration chromatography on Sephadex G-200, and electrophoretic migration on polyacrylamide gels. When fully activated by the addition of Ca2+ and microgram quantities of a purified Ca2+-binding protein (CDR), the phosphodiesterase hydrolyzed both adenosine 3′,5′-monophosphate (cyclic AMP) and guanosine 3′,5′-monophosphate (cyclic GMP), with apparent Km values of 180 and 8 μm, respectively. Approximately 15% of the total enzymic activity was present in the absence of added CDR and Ca2+. This activity exhibited apparent Km values for the two nucleotides identical to those observed for the maximally activated enzyme. Competitive substrate kinetics and heat destabilization studies demonstrated that both cyclic nucleotides were hydrolyzed by the same phosphodiesterase. The purified enzyme was identical to a Ca2+-dependent phosphodiesterase present in crude extract by the criteria of gel filtration chromatography, polyacrylamide-gel electrophoresis, and kinetic behavior.Apparent Km values of the Ca2+-dependent phosphodiesterase for cyclic AMP and cyclic GMP were lowered more than 20-fold as CDR quantities in the assay were increased to microgram amounts, whereas the respective maximal velocities remained constant. The apparent Km for Mg2+ was lowered more than 50-fold as CDR was increased to microgram amounts. Half-maximal activation of the phosphodiesterase occurred with lower amounts of CDR as a function of either increasing degrees of substrate saturation or increasing concentrations of Mg2+. At low cyclic nucleotide substrate concentrations i.e., 2.5 μm, cyclic GMP was hydrolyzed at a fourfold greater velocity than cyclic AMP. At high substrate concentrations (millimolar range) cyclic AMP was hydrolyzed at a threefold greater rate than cyclic GMP.  相似文献   

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