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101.
武汉东湖水生植被及其恢复途径探讨 总被引:4,自引:0,他引:4
1992~1993年对武汉东湖三个主要湖区(郭郑湖、汤林湖和牛巢湖)水生植被的调查表明,该湖区共有水生植物32种,优势种为大茨藻、狐尾藻、苦草和菱。金鱼藻呈不断扩大的趋势。植被类型可分为11个群丛,植被面积约为0.65km ̄2,总生物量为1236.39t(湿重),植被带状分布仅见于汤林湖北部和其他部分湖汊。汤林湖和牛巢湖水生植被正处于自然恢复演替阶段。 相似文献
102.
中药903口服液经药效学研究,表明该制剂具有良好的扶植正常菌群,调整微生态平衡,提高机体免疫能力的作用。对中药903口服液进行长期毒性实验研究结果证实,三种不同剂量组大白鼠给药前后的体重,血常规,主要脏器重量,肝、肾功能均无显著性差异。对40例大鼠11种脏器病理检查均未见药物损伤性病变。 相似文献
103.
以人胃癌细胞BGC-823为模型,研究了毛喉萜(forskolin)对胃癌细胞中蛋白激酶C活性及其亚类基因表达的作用,同时也观察了毛喉萜对癌基因c-jun及抑癌基因p53表达的影响.结果表明,2×10~(-5)mol/L毛喉萜处理BGC-823细胞72h,细胞质、膜和细胞核PKC活性下降,PKC亚类β,γ基因表达被抑制,癌基因c-jun的表达也明显降低,而抑癌基因p53表达升高,上述变化可能是毛喉萜抑制胃癌细胞增殖等生理效应的重要分子事件。 相似文献
104.
Abstract. In the Rhône delta, Juncus gerardi and Scirpus maritimus are often the dominant species in abandoned rice fields which are artificially flooded in early spring to improve forage production. Under these conditions they occur either in mixed communities, or form monospecific stands. Monitoring the vegetation dynamics in quadrats located in six abandoned rice fields artificially flooded from November to April confirmed the important role of grazing. In ungrazed plots, communities dominated by Scirpus maritimus mixed with Juncus gerardi developed fast. After 42 months of management Scirpus maritimus had established in nearly all quadrats and continued to expand, whereas Juncus gerardi had started to decline. In grazed plots Juncus gerardi alone dominated and continued to increase in cover up to the 42nd month. Scirpus maritimus established at low densities mainly in quadrats where Juncus gerardi was initially absent. Introduction of seeds of Scirpus maritimus in communities of Juncus gerardi under controlled conditions demonstrated the existence of the phenomenon of preemption. The increase in cover of Juncus gerardi suggests that the preemption of Juncus gerardi over Scirpus maritimus plays a more pronounced role in the field in the presence of grazing. 相似文献
105.
凤眼莲能够吸收和在体内聚集外源苯酚,体内的酸含量随着环境中酚浓度的上升而上升。从生长于合酚培养液中的凤眼莲体内能够检测到酚糖苷,说明凤眼莲体内有酚精苷转移酶的存在。浓度小于50mg/L的外源酚能提高凤眼莲体内的多酚氧化酶和过氧化物酶的活性。多酚氯化酶与过氧化物酶在线粒体和微粒体中均有不同程度的分布,而酚糖苷转移酶则不存在于这些细胞器中。 相似文献
106.
107.
The present study describes substance P-like immunoreactivity in the ciliary ganglia of monkey (Macaca fascicularis) and cat. About 60% of neurons in the monkey ciliary ganglion and 40% in the cat ciliary ganglion were substance P-like immunoreactive, ranging from faint to moderate staining. Substance P-like immunoreactivity was located in cell bodies, dendritic profiles and axons. In the monkey, substance P-like immunoreactive pericellular arborisations were associated with about 0.5%–3% of the ganglion cells, which were either negatively, faintly or moderately stained. An electron-microscopic study demonstrated the presence of either substance P-like immunoreactive positive or negative axon terminals synapsing or closely associated with positive dendritic profiles in both the monkey and cat ciliary ganglia. The results suggest that substance P plays an important role in the ciliary ganglion, perhaps as a modulator or transmitter. 相似文献
108.
The effect of ferredoxin(BED) overexpression on benzene dioxygenase activity in Pseudomonas putida ML2. 总被引:3,自引:3,他引:0
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H M Tan C L Joannou C E Cooper C S Butler R Cammack J R Mason 《Journal of bacteriology》1994,176(9):2507-2512
The benzene dioxygenase from Pseudomonas putida ML2 is a multicomponent complex comprising a flavoprotein reductase, a ferredoxin, and a terminal iron-sulfur protein (ISP). The catalytic activity of the isolated complex shows a nonlinear relationship with protein concentration in cell extracts, with the limiting factor for activity in vitro being ferredoxin(BED). The relative levels of the three components were analyzed by using 125I-labelled antibodies, and the functional molar ratio of ISP(BED), ferredoxin(BED), and reductase(BED) was shown to be 1:0.9:0.8, respectively. The concentration of ferredoxin(BED) was confirmed by quantitative electron paramagnetic resonance spectroscopy of the 2Fe-2S centers in ferredoxin(BED) and ISP(BED) of whole cells. These results demonstrate that the ferredoxin(BED) component is a limiting factor in dioxygenase activity in vitro. To determine if it is a limiting factor in vivo, a plasmid (pJRM606) overproducing ferredoxin(BED) was introduced into P. putida ML2. The benzene dioxygenase activity of this strain, measured in cell extracts, was fivefold greater than in the wild type, and the activity was linear with protein concentration in cell extracts above 2 mg/ml. Western blotting (immunoblotting) and electron paramagnetic resonance spectroscopic analysis confirmed an elevated level of ferredoxin(BED) protein and active redox centers in the recombinant strain. However, in these cells, the increased level of ferredoxin(BED) had no effect on the overall rate of benzene oxidation by whole cells. Thus, we conclude that ferredoxin(BED) is not limiting at the high intracellular concentration (0.48 mM) found in cells. 相似文献
109.
Panose, a major component of isomalto-oligosaccharides, was selectively produced from maltose using transglucosylation reaction catalyzed by intact cells of Aureobasidium pullulans. When 50 %(w/v) maltose was used as a substrate, the maximum concentration of panose accumulated in the final reaction mixture was about 50 %(w/w) after 120 hr reaction at 55 °C. 相似文献
110.
Summary An enzyme-immobilized microplate for determination of linamarin was prepared by covalently linking cassava leaf linamarase
to the microplate. For linamarin determination, cassava roots were homogenised in 0.1 Mo-phosphoric acid and the filtrate adjusted to pH 6 with NaOH prior to adding into the wells. The cyanide released was then
determined spectrophotometrically. One nmol linamarin can be detected. The microplate method is suitable for analysis of large
number of samples and is useful for screening purposes. 相似文献