It is critical for spring wheat (Triticum aestivum L.) production in the semi-arid Loess Plateau to understand the impact of nitrogen (N) fertilizer on changes in N metabolism, photosynthetic parameters, and their relationship with grain yield and quality. The photosynthetic capacity of flag leaves, dry matter accumulation, and N metabolite enzyme activities from anthesis to maturity were studied on a long-term fertilization trial under different N rates [0 kg ha?1(N1), 52.5 kg ha?1 (N2), 105 kg ha?1 (N3), 157.5 kg ha?1 (N4), and 210 kg ha?1 (N5)]. It was observed that N3 produced optimum total dry matter (5407 kg ha?1), 1000 grain weight (39.7 g), grain yield (2.64 t ha?1), and protein content (13.97%). Our results showed that N fertilization significantly increased photosynthetic parameters and N metabolite enzymes at all growth stages. Nitrogen harvest index, partial productivity factor, agronomic recovery efficiency, and nitrogen agronomic efficiency were decreased with increased N. Higher N rates (N3–N5) maintained higher photosynthetic capacity and dry matter accumulation and lower intercellular CO2 content. The N supply influenced NUE by improving photosynthetic properties. The N3 produced highest chlorophyll content, photosynthetic rate, stomatal conductance and transpiration rate, grain yield, grain protein, dry matter, grains weight, and N metabolite enzyme activities compared to the other rates (N1, N2, N4, and N5). Therefore, increasing N rates beyond the optimum quantity only promotes vegetative development and results in lower yields.
Lycium barbarum fruit has been used as a Chinese traditional medicine and dietary supplement for centuries. 2-O-β-d-Glucopyranosyl-l-ascorbic acid (AA-2βG), a novel stable vitamin C analog, is one of the main biologically active components of the fruit.
In this report, we investigated the cytotoxic and antiproliferative effect of AA-2βG against cancer cells in vitro and identified
the proteins with significantly differential expression in the cervical cancer cells (Hela) cultured in the presence of AA-2βG
proteomic analysis. Our results demonstrated that the cytotoxic and antiproliferative activity of AA-2βG on cancer cell lines
were in a cell type-, time-, and dose-dependent manner. Similar to vitamin C, the AA-2βG selectively induced cell death repressed
the proliferation of Hela cells by the mechanism of cell apoptosis and cell cycle arrest induced by AA-2βG through a mechanism
of stabilizing p53 protein. However, the biological activity of inhibition of cell proliferation in other malignant cancer
cell lines or primary cells were varied, as demonstrated by either moderate inhibition or slight promotion following treatment
with AA-2βG. Comparative analysis of the proteomic profiles and immunoblot analysis identified 15 proteins associated with
repressing cell apoptosis and/or stimulating cell proliferation in Hela cells that were downregulated in the presence of AA-2βG
or vitamin C. These data indicate that a mechanism of the AA-2βG and vitamin C mediated antitumor activity by downregulating
the expression of proteins involved in cell apoptosis and proliferation and consequently inducing Hela cell apoptosis and
cell cycle arrest, suggesting that AA-2βG and vitamin C may share a similar mechanism of inducing Hela cell apoptosis. These
results also suggest that the L. barbarum fruit may be a potential dietary supplement and anticancer agent aimed at the prevention and treatment of cervical cancer. 相似文献
Mucosal squamous cell carcinoma of the head and neck is a disease of high mortality and morbidity. Interactions between the
squamous cell carcinoma and the host's local immunity, and how the latter contributes to the biological behavior of the tumor
are unclear. In vivo studies have demonstrated sequential mast cell infiltration and degranulation during squamous cell carcinogenesis. The degree
of mast cell activation correlates closely with distinct phases of hyperkeratosis, dysplasia, carcinoma in-situ and invasive carcinoma. However, the role of mast cells in carcinogenesis is unclear. 相似文献
A simple and efficient tool to isolate epithelial cells from bacteria-contaminated samples has been developed using two different microparticles functionalized with chemical molecules. The epithelial cells could be captured simply by biocompatible anchors for membranes (BAM), consisting of poly(ethylene glycol) functionalized with oleyl-chain-conjugated NHS (N-hydroxysuccinimide) on glass microparticles, whereas bacteria were adsorbed on 3-aminopropyltrimethoxysilane (ATPS)-functionalized magnetic microparticles. In the case of samples highly contaminated with bacteria, epithelial cells were not isolated successfully by both of the single BAM- and antibody-functionalized microparticles. Therefore, serial isolation steps of these two different chemical functionalized microparticles were introduced. The concentration of bacteria was decreased dramatically by using APTS-functionalized magnetic particles prior to the isolation of epithelial cells by BAM microparticles. With these serial processes, successful isolation of epithelial cells was achieved from bacteria-contaminated epithelial samples. The applicability of this method was verified with bacteria-contaminated intestinal samples biopsied from a BALB/C mouse for primary cell cultivation. 相似文献
Grassland ecosystems account for more than 10% of the global CH4 sink in soils. A 4‐year field experiment found that addition of P alone did not affect CH4 uptake and experimental addition of N alone significantly suppressed CH4 uptake, whereas concurrent N and P additions suppressed CH4 uptake to a lesser degree. A meta‐analysis including 382 data points in global grasslands corroborated these findings. Global extrapolation with an empirical modelling approach estimated that contemporary N addition suppresses CH4 sink in global grassland by 11.4% and concurrent N and P deposition alleviates this suppression to 5.8%. The P alleviation of N‐suppressed CH4 sink is primarily attributed to substrate competition, defined as the competition between ammonium and CH4 for the methane mono‐oxygenase enzyme. The N and P impacts on CH4 uptake indicate that projected increases in N and P depositions might substantially affect CH4 uptake and alter the global CH4 cycle. 相似文献