In order to investigate the effects of lanthanum（Ⅲ） on cell ultrastructure of soybean leaves under elevated ultraviolet-B irradiation （UV-B, 280-320 nm）, the chloroplast ultrastructure of soybean seedlings was st...In order to investigate the effects of lanthanum（Ⅲ） on cell ultrastructure of soybean leaves under elevated ultraviolet-B irradiation （UV-B, 280-320 nm）, the chloroplast ultrastructure of soybean seedlings was studied by hydroponics under laboratory conditions. The resuits showed that the thylakoid in chloroplast was orderly and clearly as soybean leaves were pretreated by La（Ⅲ）. The thylakoid was indis- tinctly disordered, expanded and even indiscoverable in the chloroplast under UV-B stress. The impact on the thylakoid by the high intensity UV-B irradiation （T2） was bigger than that by the low intensity UV-B irradiation （T1）. However, the destruction of the chloroplast structure caused by UV-B stress was alleviated by La（Ⅲ）, and the arrangement of the thylakoid in the chloroplast became orderly and clearly. The effect of the alleviation by La（Ⅲ） under the low intensity UV-B irradiation （T1） was better than that under the high intensity UV-B irradiation （T2）.展开更多
We determined vitamin B12 content of Chinese black tea leaves using a microbiological assay based on Lactobacillus delbrueckii ATCC 7830. Trace levels (0.25 - 0.69 μg/100g dry weight) of vitamin B12 were detected in...We determined vitamin B12 content of Chinese black tea leaves using a microbiological assay based on Lactobacillus delbrueckii ATCC 7830. Trace levels (0.25 - 0.69 μg/100g dry weight) of vitamin B12 were detected in Pu’er, Fu, and Brick tea leaves. However, vitamin B12 content (0.06 - 1.37 μg/100g dry weight) of Ryubao tea leaves significantly varied. To determine whether Chinese black tea leaves contain vitamin B12 or other corrinoid compounds that are inactive in humans, corrinoid compounds were purified from Ryubao tea by an immunoaffinity column chromatography and vitamin B12 was identified by liquid chromatography-electrospray ionization/tandem mass spectrometry. Vitamin B12 content in the tea drink prepared from Ryubao tea leaves was very low (0.8 ng/100mL). Our results indicate that Chinese black tea is usually not a good source of B12, although Ryubao tea leaves with the highest B12 content may be utilized as a source of this vitamin for vegerarians.展开更多
基金supported by the National Natural Science Foundation of China (30570323)the Special Foundation for Rare Earth of State Planning Committee (IFZ20051210)
文摘In order to investigate the effects of lanthanum（Ⅲ） on cell ultrastructure of soybean leaves under elevated ultraviolet-B irradiation （UV-B, 280-320 nm）, the chloroplast ultrastructure of soybean seedlings was studied by hydroponics under laboratory conditions. The resuits showed that the thylakoid in chloroplast was orderly and clearly as soybean leaves were pretreated by La（Ⅲ）. The thylakoid was indis- tinctly disordered, expanded and even indiscoverable in the chloroplast under UV-B stress. The impact on the thylakoid by the high intensity UV-B irradiation （T2） was bigger than that by the low intensity UV-B irradiation （T1）. However, the destruction of the chloroplast structure caused by UV-B stress was alleviated by La（Ⅲ）, and the arrangement of the thylakoid in the chloroplast became orderly and clearly. The effect of the alleviation by La（Ⅲ） under the low intensity UV-B irradiation （T1） was better than that under the high intensity UV-B irradiation （T2）.
文摘We determined vitamin B12 content of Chinese black tea leaves using a microbiological assay based on Lactobacillus delbrueckii ATCC 7830. Trace levels (0.25 - 0.69 μg/100g dry weight) of vitamin B12 were detected in Pu’er, Fu, and Brick tea leaves. However, vitamin B12 content (0.06 - 1.37 μg/100g dry weight) of Ryubao tea leaves significantly varied. To determine whether Chinese black tea leaves contain vitamin B12 or other corrinoid compounds that are inactive in humans, corrinoid compounds were purified from Ryubao tea by an immunoaffinity column chromatography and vitamin B12 was identified by liquid chromatography-electrospray ionization/tandem mass spectrometry. Vitamin B12 content in the tea drink prepared from Ryubao tea leaves was very low (0.8 ng/100mL). Our results indicate that Chinese black tea is usually not a good source of B12, although Ryubao tea leaves with the highest B12 content may be utilized as a source of this vitamin for vegerarians.
