Hydrology plays a dominant role in wetland plant distribution and microbial composition, but few studies explicitly attempted to relate the linkage between wetland vegetation and microbial community. The present study...Hydrology plays a dominant role in wetland plant distribution and microbial composition, but few studies explicitly attempted to relate the linkage between wetland vegetation and microbial community. The present study consisted of five wetland plant communities along three adjacent flood gradients zones(zone 1 dominated by Carex appendiculat, zone 2 dominated by Eleocharis ovate, and zone 3 dominated by Phragmites australis/Bidens pilosa/Calamagrostis angustifolia, which formed separate, monoculture patches). Gram negative and arbuscular mycorrhizal fungal phospholipid fatty acid(PLFA) are more abundant in the site with short flooding period(zone 3) than in the site with long flooding period(zone 1), and they are also different in the P. australis, B. spilosa and C. angustifolia of zone 3. Principle Component Analysis(PCA) showed that the flooding period could explain 92.4% of variance in microbial composition. Redundancy Analysis(RDA) showed that available nitrogen(AN), total nitrogen(TN) and soil organic matter(SOM) could explain the 79.5% of variance in microbial composition among E. ovata, P. australis, B. pilosa and C. angustifolia. Results demonstrated that flooding period was the main factor in driving the microbial composition and plant-derived resources could influence soil microbial composition in the seasonally flooded zones.展开更多
Polyunsaturated fatty acids （PUFAs） possess anti-cancer action both in vitro and in vivo. In the present study, we detected cell viability with methyl thiazolyl tetrazolium （MTT） assay and cell membrane permeabili...Polyunsaturated fatty acids （PUFAs） possess anti-cancer action both in vitro and in vivo. In the present study, we detected cell viability with methyl thiazolyl tetrazolium （MTT） assay and cell membrane permeability with propidium iodide （PI） fluorescence dyeing, and calculated cell membrane fluidity change as fluorescence anisotropy. Fatty acid content in cells was measured by gas chromatography/mass spectroscopy （GC/MS）, and the relationship between fatty acid composition and cell viability was studied. We observed that n-6 PUFA linoleic acid （LA） inhibited tumor cell growth at high concentrations （〉300 μmol/L）, while low concentrations （100-200 μmol/L） seemed to promote cell proliferation. Analyses of cell membrane permeability, cell membrane fluidity, and cell fatty acid composition suggested that the anti-cancer action of LA could be related to changes in the ratio of n-6 to n-3 PUFAs. We observed that pre-incubation of cancer cells with 100 μmol/L LA for 24 h enhanced cell sensitivity to the cytotoxic action of LA, whereas undifferentiated cell line LoVo seemed to have a distinct path in LA-induced death. These results showed that one of the mechanisms by which supplementation of LA induces cancer cell death could be altering the ratio of n-6/n-3 PUFAs, and this may be related to celt differentiation status.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.41361015,41271106,41271107,41501105)Open Fund of the State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration,Northeast Normal University(No.130028630)
文摘Hydrology plays a dominant role in wetland plant distribution and microbial composition, but few studies explicitly attempted to relate the linkage between wetland vegetation and microbial community. The present study consisted of five wetland plant communities along three adjacent flood gradients zones(zone 1 dominated by Carex appendiculat, zone 2 dominated by Eleocharis ovate, and zone 3 dominated by Phragmites australis/Bidens pilosa/Calamagrostis angustifolia, which formed separate, monoculture patches). Gram negative and arbuscular mycorrhizal fungal phospholipid fatty acid(PLFA) are more abundant in the site with short flooding period(zone 3) than in the site with long flooding period(zone 1), and they are also different in the P. australis, B. spilosa and C. angustifolia of zone 3. Principle Component Analysis(PCA) showed that the flooding period could explain 92.4% of variance in microbial composition. Redundancy Analysis(RDA) showed that available nitrogen(AN), total nitrogen(TN) and soil organic matter(SOM) could explain the 79.5% of variance in microbial composition among E. ovata, P. australis, B. pilosa and C. angustifolia. Results demonstrated that flooding period was the main factor in driving the microbial composition and plant-derived resources could influence soil microbial composition in the seasonally flooded zones.
文摘Polyunsaturated fatty acids （PUFAs） possess anti-cancer action both in vitro and in vivo. In the present study, we detected cell viability with methyl thiazolyl tetrazolium （MTT） assay and cell membrane permeability with propidium iodide （PI） fluorescence dyeing, and calculated cell membrane fluidity change as fluorescence anisotropy. Fatty acid content in cells was measured by gas chromatography/mass spectroscopy （GC/MS）, and the relationship between fatty acid composition and cell viability was studied. We observed that n-6 PUFA linoleic acid （LA） inhibited tumor cell growth at high concentrations （〉300 μmol/L）, while low concentrations （100-200 μmol/L） seemed to promote cell proliferation. Analyses of cell membrane permeability, cell membrane fluidity, and cell fatty acid composition suggested that the anti-cancer action of LA could be related to changes in the ratio of n-6 to n-3 PUFAs. We observed that pre-incubation of cancer cells with 100 μmol/L LA for 24 h enhanced cell sensitivity to the cytotoxic action of LA, whereas undifferentiated cell line LoVo seemed to have a distinct path in LA-induced death. These results showed that one of the mechanisms by which supplementation of LA induces cancer cell death could be altering the ratio of n-6/n-3 PUFAs, and this may be related to celt differentiation status.
