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61.
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Nigel J. Kilby David L. Griggs Stephanie F. Berry 《Plant Cell, Tissue and Organ Culture》1992,28(3):275-280
Intra-population quinoline alkaloid profiles surveying quinine, quinidine, cinchonine and cinchonidine were determined for each of five populations of Cinchona ledgeriana grown as shoot-culture for 125 days. No significant difference in respect of mean alkaloid content between populations was detected. In contrast, there was considerable between-seedling variation in alkaloid content within each population. When nutrients were delivered to shoot-cultures in droplet form by means of an aerosol spray (as compared to the supply of nutrients direct from agar-or liquid-based reservoirs) alkaloid profile was greatly perturbed; most notable in this respect was a four-fold increase in the production of cinchonidine concomitant with a four-fold decrease in the production of cinchonine. These data are discussed with reference to the optimisation of quinoline alkaloid production by juvenile shoot-cultures of Cinchona ledgeriana. 相似文献
63.
The gene for β-microseminoprotein MSMB has been studied by DNA hybridization and molecular cloning techniques. Comparative analysis of restriction endonuclease digests of the cloned gene and of leukocyte DNA strongly suggested that the gene is present in a single copy in the haploid human genome. By Southern blot analysis of DNA from somatic cell hybrids, the gene was assigned to chromosome 10. The coding nucleotides of the human gene are separated into four exons by relatively large introns. A related gene might be present in other mammals, birds, and amphibians as revealed by DNA hybridization under conditions of low stringency. 相似文献
64.
We have examined a serum-deprived culture system in order to verify that it is suitable for the study of burst forming unit erythroid (BFU-E) progenitor cells from premature neonates. Optimum growth of BFU-E from premature neonates was observed with each media constituent using the same concentration as that previously described for adult subjects. Growth of immature BFU-E from premature neonates were highly dependant upon a source of Burst Promoting Activity and mature BFU-E derived colonies emerged at day 12 compared to day 14 in adults. Our preliminary results with the validated medium suggest that premature infants have increased peripheral blood concentrations of BFU-E compared to healthy adult controls.Abbreviations Ad
Adherent cells
- BPA
Burst promoting activity
- BFU-E
Burst forming unit erythroid
- Epo
Erythropoietin
- IL3
Interleukin-3
- LDC
Low density (<1.077 g ml1) peripheral blood mononuclear cells 相似文献
65.
Summary Ornithine decarboxylase activity was measured during organogenesis in rat embryos grown in utero and whole rat conceptuses
maintained in an in vitro culture system. Ornithine decarboxylase levels in vivo showed a distinct peak at embryonic age 10.5
d. Despite identical morphology, protein content, crown rump length and numbers of somites cultured embryos displayed a different
developmental pattern and possessed less than half the ODC activity of that in vivo. The data suggest that the normal embryonic
programming of ODC activity is significantly altered by the culture environment and that further biochemical comparisons of
embryos growing in utero and in vitro may be required to evaluate properly the applicability of this technique to detailed
studies of teratogenesis and developmental biology.
This work was supported by NIH-5-507-RR5359-17 and a 1980 Research Starter Grant from the Pharmaceutical Manufacturers Association
Foundation. 相似文献
66.
A colony of the Edible-nest Swiftlet Aerodramus fuciphagus nesting in a Chinese shophouse in Penang, Peninsular Malaysia, was studied for seven months. Birds bred throughout, but laying was concentrated in the period October to February. Incubation and fledging periods were 23 ± 3 days and 43 + 6 days, respectively. Most young hatched during the dry season. The normal clutch size was two, with many birds laying second clutches (75%) and some third clutches (15-4%) using the same nest. Clutch size showed no variation with clutch order or month. The overall hatching success was 69-0 %, most losses caused by eggs falling from or with the nest. Fledging success was similar for broods of two (625%) and broods of one (59-4%), so that the former were twice as productive. The main loss of chicks occurred when they fell from the nest and were eaten by mammalian predators. There was a tendency for breeding success to decline with successive clutches, but not with month, being highest in November (53-6 %) and February (55-6 %). The growth rate of single chicks and successful broods of two was similar, except that the second chick was more prone to fluctuations in weight. Some second chicks showed evidence of starvation before falling from the nest. Diet was examined by analysis of foodballs regurgitated by mist-netted adults. Foodballs weighed 0–13-1 08 g and, on average, contained over 500 prey items. The main arthropods caught were Hymenoptera (40-8%), Ephemeroptera (26-4%), Homoptera (15-4%) and Diptera (7-7%). Flying ants and mayflies contributed most by weight, although figwasps and mayflies were the most numerous prey items. Only in December did the percentage of moulting mist-netted adult swiftlets fall below 70 %. It appeared that many birds were moulting and breeding simultaneously, although 21% of birds had primaries moulting in two places, suggesting arrested moult. Diurnal activity showed a normal high dawn exodus and dusk inflow of birds, although there was evidence of an increase of birds flying out prior to the dusk inflow. Nest harvesting was continued throughout the study, but most of the marked nests under study were left undisturbed. 相似文献
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69.
Herbivore damage along a latitudinal gradient: relative impacts of different feeding guilds 总被引:3,自引:0,他引:3
We present the first broad-scale test for a latitudinal gradient in herbivory made with consistent methods, in similar habitat type, over the entire lifespan of leaves (phyllodes). We assessed the degree of chewing, sap-sucking and mining herbivory on Acacia falcata along its entire coastal latitudinal range (1150 km) in Australia. We found no significant differences in the rate of herbivory among latitudes. Mature phyllodes had a higher rate of herbivory compared to young phyllodes, and mining was higher on mature phyllodes from the most tropical latitude. We found significant differences in phyllode toughness and specific leaf (phyllode) area among latitudes, but no significant differences among latitudes in carbon: nitrogen. This study provides a useful model for further testing of the generalisation that herbivory is more intense in tropical versus temperate regions. 相似文献
70.