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101.
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- Studies of floral polymorphisms have focused on heterostyly, while stigma‐height dimorphism has received considerably less attention. Few studies have examined the reproductive biology of species with stigma‐height dimorphism to understand how factors influencing mate availability and pollen transfer are related to morph ratios in populations.
- Floral morphological traits, especially herkogamy and reciprocity, pollinator visitation, breeding system and spatiotemporal mate availability, are known to affect inter‐morph pollination and morph ratios in species with stigma‐height dimorphism. In this study, we investigated the presence of stigma‐height dimorphism and estimated morph ratios in four naturally occurring populations of Jasminum malabaricum. We quantified morph‐ and population‐specific differences in the abovementioned factors in these populations to understand the observed morph ratios.
- The positions of anthers and stigmas were characteristic of stigma‐height dimorphism, the first report of this polymorphism in the genus. All study populations were isoplethic, implying equal fitness of both morphs. Herkogamy was higher in the short‐styled morph, while reciprocity was higher between the long‐styled stigma and short‐styled anthers. Long‐ and short‐tongued pollinators were common floral visitors, and we observed no differences between morphs in spatiotemporal mate availability or pollinator visitation. Neither morph exhibited self‐ or heteromorphic incompatibility.
- The short‐styled stigma had lower reciprocity but likely receives sufficient inter‐morph pollen from long‐tongued pollinators, and also by avoiding self‐pollination due to higher herkogamy. These results highlight the importance of sufficient effective pollinators and floral morphological features, particularly herkogamy, in maintaining isoplethy in species with stigma‐height dimorphism.
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The distribution of vitamin A ester, alcohol, and lutein was studied in fractions of chicken plasma proteins obtained by ammonium sulfate fractionation or dialysis, 6–8 hr. after oral administration of vitamin A and lutein in an oily medium. The losses of vitamin A and carotenoids during fractionation were considerable in some cases, losses of vitamin A being as large as 50% at times. Although this made the interpretation of the distribution between precipitate and supernatant difficult, the following conclusions seem to be possible. Vitamin A ester was found to be associated with the least soluble, and vitamin A alcohol and lutein with the more soluble protein fractions. No mono- or diesters of lutein could be demonstrated in the plasma. 相似文献
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Cellular retinol-binding protein was purified from the cytosol of the oviducts of laying hens by ammonium sulphate fractionation and chromatography on Sephadex G-75 and DEAE-Sephadex A-50 columns. Analysis of the purified retinol-binding protein on 10% SDS-polyacrylamide gel revealed the presence of a doublet representing very similar molecular sizes. Antiserum was prepared against the purified cellular retinol-binding protein, and on the basis of (a) immunodiffusion test and (b) immunoneutralization of 3H-labelled retinol-cellular retinol-binding protein complex on a column of Sephadex G-75, the antiserum appeared to be specific. The antiserum showed cross-reactivity with the nucleosol and a 0.4 M NaCl extract of the chromatin of the oviduct nuclei, while it did not react with the major egg-white proteins such as ovalbumin, conalbumin and ovomucoid. 相似文献
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K. Sreenivas Nirmal K. Ganguly Sujata Ghosh Rakesh Sehgal Ramesh C. Mahajan 《FEMS microbiology letters》1995,134(1):33-37
Abstract A lectin specific for α-methyl-d-mannoside was purified from the membrane extract of Giardia lamblia by a combination of gel filtration chromatography on Sephadex G-75 and Superose 6-HR 10/30. The homogeneity of the lectin was established by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The molecular mass of the native protein was 148 kDa. The lectin agglutinated rabbit erythrocytes in the presence of Ca2+ at 37 °C and pH 7.O. The maximum activity of the lectin was obtained after trypsin treatment. The inhibition study clearly suggests that the binding site of the lectin recognizes α-methyl-d-mannoside as the immunodominant sugar. 相似文献
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Abstract A partially purified Escherichia coli heat-stable (ST) enterotoxin had been shown to increase the 45 Ca2+ uptake by rat intestinal brush-border membrane vesicles (BBMV). The effect of ST enterotoxin on calcium uptake by BBMV was significant compared with the control and was also dose-dependent. The stimulation of calcium uptake by ST enterotoxin was inhibited by chemical agents which block the calcium entry into the cell. These data indicate that the ST acts as calcium ionophore in this particular system. 相似文献