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71.
W. M. Blaney M. S. J. Simmonds S. V. Evans L. E. Fellows 《Entomologia Experimentalis et Applicata》1984,36(3):209-216
The cyclic amino alditol 2,5-dihydroxymethyl 3,4-dihydroxypyrrolidine (DMDP) has recently been shown to be an inhibitor of various glucosidases. We have investigated its role as a plant protective chemical against a range of phytophagous insects by examining its effects on development, feeding behaviour and functioning of taste receptors. We have shown that it can inhibit feeding and can be toxic. The mechanisms by which these effects are achieved are discussed in the context of the molecular structure of the compound.
Résumé Récemment a été mis en évidence le puissant pouvoir inhibiteur de différents glucosidases. Présenté par l'amino-alditol cyclique, 2,5 dihydroxymethyl 3,4 dihydroxypyrrolidine (DMDP), isolé de graines de la légumineuse Lonchocarpus sericeus. Nous avons examiné le rôle de ce composé secondaire dans la stratégie défensive de la plante contre une gamme d'insectes phytophages, à travers son action sur le développement, le comportement alimentaire et le fonctionnement des récepteurs gustatifs. Nous avons montré que DMDP peut inhiber, suivant la dose, la prise de nourriture et, qu'aprs ingestion (par Spodoptera spp), il peut agir comme une toxine. Par suite de sa structure moléculaire, DMDP peut être considéré, non seulement comme l'analogue d'un sucre, mais aussi comme un alcaloïde. Le bilan des résultats de nos expériences suggère que l'efficacité de DMDP comme phagodissuadant, si elle ne provient pas de sa toxicité, découle principalement de ses propriétés d'alcaloïde.相似文献
72.
73.
The n-hexane soluble non-volatile fraction of the acetone extracts from the flower buds, the flowers and the immature and the mature fruits of Fatsia japonica were all found to contain fatty acids, fatty acid methyl esters, squalene, β-amyrin and sterols. At all the stages between budding to the mature fruit, the major fatty acids were palmitic and linoleic acids and the major phytosterol was stigmasterol. In addition steryl and β-amyrenyl esters were found in the flowers and the immature and the mature fruits, but these esters were not present in the flower buds. Sitosteryl ester was the major constituent of the steryl ester fraction in the fruiting stages. Phytol was found in only the flowering stage and triglycerides in only the mature fruits. The variations in the lipid constituents is discussed in relation to the stages from budding to the mature fruit. 相似文献
74.
Ferdinand Bohlmann Karl-Heinz Knoll Christa Zdero Pradip Kumar Mahanta Michael Grenz Albert Suwita Dorothea Ehlers Ngo Le Van Wolf-Rainer Abraham Arvind Anant Natu 《Phytochemistry》1977,16(7):965-985
Investigation of about 50 Senecio species has afforded many new substances, in addition to known compounds. Present in these plants are 23 fura 相似文献
75.
Effector studies with two isoenzymes (I and IV) of glucose-6-phosphate dehydrogenase (G6PDH) from tobacco suspension culture WR-132 revealed that chlorogenic acid, at 0.4 mM, inhibited both isoenzymes almost 100%, with the inhibition decreasing as the concentration of the acid was reduced. At 0.3 and 0.4 mM, the coumarin glucosides scopolin and esculin were inhibitory, whereas their aglucones scopoletin and esculetin were less inhibitory, and at low concentrations of glucose-6-phosphate (G6P), the latter two were actually stimulatory for G6PDH I. Of the possible effectors studied, only scopoletin and esculetin exhibited a significant activation of G6PDH I under these conditions. However, with G6PDH IV these two effectors do not show the same marked activation at the low G6P concentrations. The phenolic acids, caffeic and ferulic, were less inhibitory than the coumarins tested. The activation of G6PDH I by scopoletin, a compound which accumulates in tobacco under certain stress conditions, gives a possible clue as to the resulting enhanced activity of the hexose monophosphate pathway that has been reported for some plants subjected to stress conditions. 相似文献
76.
Burckhard Viell 《Planta》1977,137(1):13-18
Microfragments of constant size were isolated from the thallus of Riella by a rapid punching procedure. Thus it was possible to study various metabolic parameters especially during the first hours after fragment isolation. Protein synthesis increases rapidly after a slight decrease at 30 min. The earliest significant increase in RNA synthesis occurs at 8 h, indicating a different activation pattern. The concentration of -amino compounds drops at 30 min and then increases continuously, thus exhibiting a close relationship with the measured alterations in protein synthesis. Another indication of metabolic conversions during regeneration is provided by the changing level of free radioactive leucine, which shows a marked turning point at 24 h after fragmentation. Analysis of free -amino concentrations in small regions of larger fragments also indicates the establishment of new intercellular correlations only a few hours after isolation of the cells from the meristem. Up to the 8th h after fragmentation, the contents of both the adaxial and peripheral fragment regions increase. Thereafter only the adaxial (regenerating) cells continue accumulating; the peripheral (nonregenerating) ones remain at the same level. 相似文献
77.
B. F. Lownsbery E. H. Moody A. Moretto G. R. Noel T. M. Burlando 《Journal of nematology》1978,10(3):232-236
Preplanting treatment of soil naturally infested with Macroposthonia xenoplax with 1,2-dibromoethane (ethylene dibromide) significantly increased the growth rate of Juglans hindsii seedlings. When seedlings of J. hindsii, J. regia CV "Serf" and J. regia CV Eureka were inoculated with M. xenoplax, their growth was signilicantly less than that of nematode-free controls. This retarded growth rate was accompanied hy feeder root necrosis, longitudinal cracks in the older roots, and distinct lesions in the secondary phloem. 相似文献
78.
The inclusion of sub-lethal amounts ofthe herbicide atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] in the nutrient solution supplied to maize and barley increased the growth of the root and shoot and the uptake of nitrate. The activities of nitrate and nitrite reductases, glutamine synthetase and glutamate synthase were enhanced and the amino acid and nitrate contents of the xylem sap increased. All these effects of atrazine were found only in plants grown with nitrate as the nitrogen source. The uptake of 15NO3? and its incorporation into protein in the root and shoot of maize and barley seedlings was significantly greater in the atrazine treated plants. However, a stimulation in the incorporation of leucine-[14C] into TCA-precipitable protein of detached leaves from 7-day-old barley seedlings was obtained only in the absence of a supply of combined nitrogen either in the culture medium or in the in vitro incubation mixture containing the labelled amino acid. 相似文献
79.
32P was applied to a Laminaria digitata thallus and the pattern of 32P phosphorylated compounds was studied, as a function of time, in the different tissues involved in translocation, i.e. source, pathway and sinks. The results showed that, 3 hours after absorption by the uptake region (lamina), the bulk of the radioactivity was incorporated into organic compounds (70 to 80% of total 32P taken up), hexose monophosphates being the heaviest labelled. Further change in that region was marked by an accumulation of 32P in the inorganic pool (65 to 70% after 13 days). Conversely, the 32P pattern in the medulla of the stipe, which initially showed a similar pattern to the uptake region, did not vary during translocation. The pattern of 32P distribution into sinks (growing stipe peripheral tissue or hapteron) leads to accumulation of the radioactive element in inorganic and acid-insoluble fractions. These results are discussed in terms of comparative distribution of 32P in the different parts of the thallus and suggest that phosphate moves as Pi in that alga.Abbreviations TCA
trichloroacetic acid
- Po
organic phosphate
- Po sol
acid-soluble organic phosphate fraction
- Po insol
acidinsoluble organic phosphate fraction
- Pi
morganic phosphate fraction
- P lip
lipidic phosphate
- Np
protein nitrogen
- ATP
adenosine triphosphate
- ADP
adenosine diphosphate
- PEP
phosphoenolpyruvic acid
- PGA
phosphoglyceric acid
- G-1-P
glucose-1-phosphate
- G-6-P
glucose-6-phosphate
- UDPG
uridine diphosphoglucose 相似文献
80.
Yamazaki Y Hosono K Matsuda H Minami N Asai M Nakanishi H 《Biotechnology and bioengineering》1991,38(10):1218-1222
Twelve species of optically active metallocene derivatives having a 4-nitrophenyl group were prepared with horse liver alcohol dehydrogenase- or lipase-catalyzed optical resolution as the key step. The second harmonic generation (SHG) efficiently of these products was measured by the power method using the fundamental light from the Nd:YAG laser. (-)-1- (4-Nitrophenylthio)ethylferrocene (9), (+)-1-(4-nitrophenylthio)ethylruthenocene (16), (+)-1-(4-nitrophenylthio)ethylosmocene (19), (+) -1-(5-nitro-2-pyridylthio)ethylruthenocene (21), and (+) -1-[(4-nitrophenylhydrazono)methyl] -2-methylferrocene (12) showed SHG signals. The highest SHG efficiency was found with (+) -16, being 27 times more intense than the commonly used urea standard. 相似文献