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991.
气候变暖可能对东北三省农业生态环境的影响及其对策 总被引:8,自引:0,他引:8
随着未来气候变暖,我国东北三省农业生态环境可能发生较大的变化,其变化趋势为,热量条件变好,作物生育期延长,冷害频率降低,积雪期缩短,湿润条件变差,干旱频率增大,蒸发量增加。未来气候变暖,若平均气温升高2℃,那时东北三省粮食产量可增加36%左右,农业地带将大幅度地向北推移,并且提出相应的农业对策。 相似文献
992.
应用PCR重组技术,对大肠杆菌分泌型表达载体pIN-ⅢompA进行改建,除去原载体的HindⅢ位点,将信号肽序列末端两个密码子CAGGCC改为CAAGCT,从而引入一个新的HindⅢ位点,并在其下游接上一段多克隆位点序列。改建后的载体可用于直接插入外源DNA编码序列,表达产物在分泌过程中被切除信号肽而成为天然有活性的蛋白质,操作十分简便。 相似文献
993.
Aconitum kusnezoffii Reichb., one of the earliest recorded toxic species of genus Aconitum, has been used as traditional Chinese medicine and medicinal diet over the last 2500 years to treat heart failure congestion, neuralgia, rheumatism and gout, etc. In the present paper, four water-soluble polysaccharide fractions isolated from the tubers of A. kusnezoffii Reichb. were studied the antioxidant and immunological activities for the first time. In vitro antioxidant assays indicated that fraction WKCP-A had noticeable scavenging activities on DPPH radical, hydroxyl radical, superoxide anion, H2O2 and self-oxidation of 1,2,3-phentriol, ferrous ion-chelating ability and reducing power. Moreover, the in vivo immunological assay exhibited that fractions WKCP-A and WKHP could more significantly enhance splenic lymphocyte proliferation and macrophage phagocytosis than other fractions. Therefore, the water-soluble polysaccharides from A. kusnezoffii Reichb., especially WKCP-A, have the potential to be explored as novel natural antioxidants and immunostimulating agents for using in functional foods or medicine. 相似文献
994.
Dry distiller’s grain and solubles (DDGS) is a major by-product of corn-based ethanol production and is usually used as animal
feed. Here, it was added to the simultaneous saccharification and ethanol fermentation (SSF) carried out at high solids loading
of steam explosion pretreated corn stover using a mutant strain Saccharomyces cerevisiae DQ1. The performance of SSF process with DDGS was comparable to those using the expensive yeast extract supplementation.
With 30% (w/w) solids plus the addition of cellulase and 1 g DDGS l−1, the final ethanol reached 55 g l−1 (7% v/v). The results indicated that the expensive supplement of yeast extract could be replaced by DDGS. 相似文献
995.
996.
Qiuxin Wu Dadong Guo Hongsheng Bi Daoguang Wang Yuxiang Du 《Molecular and cellular biochemistry》2013,382(1-2):263-272
Ultraviolet B (UVB) could lead to the apoptosis of human lens epithelial cell and be hypothesized to be one of the important factors of cataractogenesis. In the human lens, Ca2+-ATPase is a major determinant of calcium homeostasis. Plasma membrane calcium ATPase1 (PMCA1) is a putative “housekeeping” isoform and is widely expressed in all tissues and cells, which plays an important role in calcium homeostasis. However, the effects of UVB-irradiation on the expression of PMCA1 and the cellular calcium homeostasis are still unclear. In the present study, we cultured human lens epithelial cells (HLE B-3) in vitro and investigated the effects of UVB irradiation on the expression of PMCA1 and the intracellular calcium homeostasis using real-time cell electronic sensing system, flow cytometry, fluo-3/AM probes, real-time quantitative PCR, and enzyme-linked immunosorbent assay techniques. We found that UVB irradiation could induce human lens epithelial cell death, cause intracellular calcium ion (Ca2+) elevation, inhibit Ca2+-ATPase activity and decrease the expression of PMCA1 at gene and protein levels, suggesting that the downregulation of PMCA1 and the disruption of calcium homeostasis may play important roles in UVB-induced HLE B-3 cell apoptosis. 相似文献
997.
998.
运用主分量分析法对霍山东、西两坡的105个样方进行了排序。前3个主分量占总信息量的70%左右。降维效果良好。排序图中,样方间距离抽象地表达了群落间的生态学相关程度。据此将所作样方划分为若干群系,分析了群落随环境梯度变化的规律、观测了群落演替的趋向。从而证明PCA法在该区森林群落研究中具有良好的适应性。 相似文献
999.
1000.
Peng Zheng Jieyu Ge Jiayi Ji Jingling Zhong Hongyu Chen Daren Luo Wei Li Bo Bi Yongjun Ma Wanghui Tong Leiqin Han Siqi Ma Yuqi Zhang Jianping Wu Yanqiu Zhao Ronghui Pan Pengxiang Fan Mengzhu Lu Hao Du 《Plant biotechnology journal》2023,21(8):1671-1681
The fungal bioluminescence pathway (FBP) was identified from glowing fungi, which releases self-sustained visible green luminescence. However, weak bioluminescence limits the potential application of the bioluminescence system. Here, we screened and characterized a C3′H1 (4-coumaroyl shikimate/quinate 3′-hydroxylase) gene from Brassica napus, which efficiently converts p-coumaroyl shikimate to caffeic acid and hispidin. Simultaneous expression of BnC3′H1 and NPGA (null-pigment mutant in A. nidulans) produces more caffeic acid and hispidin as the natural precursor of luciferin and significantly intensifies the original fungal bioluminescence pathway (oFBP). Thus, we successfully created enhanced FBP (eFBP) plants emitting 3 × 1011 photons/min/cm2, sufficient to illuminate its surroundings and visualize words clearly in the dark. The glowing plants provide sustainable and bio-renewable illumination for the naked eyes, and manifest distinct responses to diverse environmental conditions via caffeic acid biosynthesis pathway. Importantly, we revealed that the biosynthesis of caffeic acid and hispidin in eFBP plants derived from the sugar pathway, and the inhibitors of the energy production system significantly reduced the luminescence signal rapidly from eFBP plants, suggesting that the FBP system coupled with the luciferin metabolic flux functions in an energy-driven way. These findings lay the groundwork for genetically creating stronger eFBP plants and developing more powerful biological tools with the FBP system. 相似文献