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Of a group of 32 patients with diabetes, 26 had a favorable modification of the disease in response to administration of butyl-sulfonyl-urea. All but one of the patients who had good response were past the age of 38. All diabetic patients included in this group were those with little or no tendency to ketosis after cessation of insulin administration. No toxic manifestations were noted except for a slight decrease in leukocytes in one case. 相似文献
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Abstract Variability in spatial and temporal patterning of flowering by populations of rainforest trees fed upon by honeyeaters and flower-visiting parrots was studied for 2 years in lowland tropical hill forest in Papua New Guinea. All 2200 trees in a 3 ha plot were tagged, identified, mapped and monitored monthly. Of 274 tree species present, 86 flowered during the course of the study; during any given month, approximately 20% of the species flowering that month were visited by nectarivorous birds. Results showed that overall flower resources (total number of species, and number of bird-pollinated species, individuals and flowers) fluctuated during the year, decreased during the dry season and increased during the wet season. In addition, there was a wide range of temporal variation within and among tree species in length and timing of flowering period, percentage of each conspecific population flowering from year to year, and degree of synchrony among flowering conspecifics. Spatial dispersion of tree populations also varied, from clumps to scattered single individuals. Resident bird species were correlated with synchronously flowering trees, whereas nomadic bird species were correlated with asynchronously flowering trees. Resident birds were also associated with smaller blooming displays per tree, whereas nomadic birds were associated with trees that bloomed massively. There was no correlation between avian nomadism and spatial dispersion of tree populations. Thus nomadic birds seem to range in search of rich but unpredictable resources; resident birds may rely more on predictable, but smaller resources. 相似文献
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The Japanese snipe Gallinago hardwickii breeds in Japan and migrates south, through New Guinea, to spend the southern summer in Australia. There is no acceptable evidence yet that it reaches the continent other than in north Queensland. Its movement in Australia is mainly coastal Most of the population spends the summer south of the Richmond River, New South Wales: elsewhere it is a passage migrant. Little is known of the movements of individual birds as few have been banded. The distribution of the species and that of G. megala in Australia is discussed. There is no evidence of sexual activity whilst the birds are in Australia. Pre-migratory fattening begins in February and in birds that had spent the summer in the highlands most fattening takes place at lower altitudes. There is a complete moult while the birds are in Australia. The food consists of animal and plant material, including seeds. The principal animals eaten are the larvae of insects and earthworms. In Japan the bird breeds away from water in grassland, often in elevated dry situations. In Australia it frequents highland and lowland freshwater and occasionally saline habitats. In Japan much habitat has been destroyed but areas cleared for re-afforestation provide suitable breeding places and the continued production of these disclimax communities results in regeneration of suitable breeding habitat. In Australia most habitat alteration is detrimental to the species and hence its population is not secure. 相似文献
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Activity of ferredoxin-NADP+ reductase in leaf extracts of eastern hemlock [Tsuga canadensis (L.) Carr.] was relatively low, but could be markedly increased by use of protective agents. The best method employed polyvinylpolypyrrolidone (PVP) in the extraction medium plus removal of phenolic compounds by filtering the extracts through an insoluble PVP (Polyclar AT) column. Further purification of the enzyme was achieved by means of DEAE cellulose chromatography and DEAE Sephadex chromatography. A 94-fold purification of the enzyme with a total recovery of 43% was obtained. The eastern hemlock ferredoxin-NADP+ reductase was characterized by its diaphorase activity, i.e. the transfer of electrons from NADPH to an electron acceptor. 2,6-dichlorophenol indophenol. The pH optimum for the oxidation of NADPH is between 8.5 and 9.0. The enzyme is highly specific for its electron donor. NADPH, but shows low specificity for electron acceptors. The apparent Michaelis constant values of the enzyme for NADPH. NADH, and 2,6-dichlorophenol indophenol are 2.4 × 10?5, 5.4 × 10?3, and 4.7 × 10?5M respectively. The molecular weight of the enzyme, as estimated by gel filtration, is about 45,000. The enzyme is inhibited by both organic and inorganic mercurials and certain cations. Comparison of properties of eastern hemlock ferredoxin-NADP+ reductase and spinach ferredoxin-NADP+ reductase shows that both enzymes are similar. 相似文献
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Nitrate Reductase Activity in Calcifugous and Calcicolous Tomatoes as Affected by Iron Stress 总被引:1,自引:0,他引:1
Calcicolous plants are generally more Fe-efficient than calcifugous plants, because they respond to Fe stress by releasing H-ions and “reductants” from their roots that causes Fe to become available. The objective of our study was to determine if differential response to Fe stress in calcicolous and calcifugous varieties affects nitrate reductase activity. T3238FER (Fe-efficient) and T3238fer (Fe-inefficient) tomato (Lycopersicon esculentum Mill.) cultivars were grown in nutrient solutions supplied with N as NH4+-N plus NO3?-N, and as NO3?-N only. The chemical reactions induced by Fe stress concomitantly increased nitrate reductase activity in roots and tops of calcicolous, but not in calcifugous tomato. This nitrate reductase activity decreased, however, when Fe was made available to the plants. When Fe stress was eliminated by adding Fe, nitrate reductase activity was comparable in the two cultivars. 相似文献
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