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1.
BIOCHEMICAL AND SYMBIOTIC PROPERTIES OF THE RHIZOBIA   总被引:2,自引:0,他引:2       下载免费PDF全文
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2.
6-aminodopamine was injected intraperitoneally into male Swiss–Webster mice. At 72 h post injection 6-aminodopamine had caused a reduction in the endogenous content of heart norepinephrine, a decrease in the capacity of heart slices to accumulate [3H]-norepinephrine in vitro, and a virtual disappearance of the adrenergic plexus of the mouse iris as viewed by fluorescence histochemistry. Similar data were obtained with the same dose of 6-hydroxydopamine. These data suggest that 6-aminodopamine causes a destruction of sympathetic nerve terminals. Model experiments showed that 6-aminodopamine, like 6-hydroxydopamine, generated H2o2both in vitro and in vivo. 6-Aminodopamine, like 6-hydroxydopamine, also blocked the accumulation of [3H]dopamine into slices of rat brain in vitro.  相似文献   

3.
本文首先应用拉曼光谱对柿树叶进行表征,发现特征峰主要在2906、1607、1525和1156cm^-1。然后根据Washurn的浸渍理论(Penetratiin Theory)、van Oss-Chaudhury-Good的组合理论(Combining Rules)及应用柱状灯芯技术(Column Wicking Technique)对柿树叶表面性能进行了分析。发现柿树叶有较大的表面能,而表面能的主要成分是Lifshitz-van der Waals力,约占84%。柿树叶中Lewis酸和Lewis碱之比(酸碱比)约为0.016。  相似文献   

4.
不同微生物的α—乙酰乳酸脱羧酶的生理生化特性的研究   总被引:7,自引:0,他引:7  
分析测定了不同微生物的α-乙酰乳酸脱羧酶(ALDC)酶活力,结果表明不同来源的ALDC酶力有较大差异,酶反应速度曲线存在明显差异;酶反应体系的pH对ALDC酶活力有明显的影响,如乳酸乳球菌的ALDC酶反应最适PH为6.6,而产气气杆菌的ALDC酶反应的最适PH为5.8,酶反应体系中加入不同浓度的亮氨酸,缬氨酸和异亮氨酸对不同来源的ALDC酶活性有较明显的影响。  相似文献   

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A simple and rapid method is described for the isolation of the acidophilic and basophilic granules from the anterior pituitary gland of the rat. The method involves chromatography of pituitary particulates on columns of No. 545 Celite equilibrated and developed with 0.25 M sucrose. Mitochondria are retained quantitatively on the column. The granules and microsomes which are not retained on the Celite are further fractionated on a discontinuous density sucrose gradient and by differential centrifugation. Essentially homogeneous populations of acidophilic and basophilic granules were obtained as indicated by 1) extensive electron microscopic studies, 2) enzymatic determinations, and 3) fatty acid and RNA analyses on the granule pellets. Microfiltration studies indicated that the acidophilic granules were smaller than 450 mµ, but greater than 300 mµ in diameter. They were found, unlike the basophilic granules, to be partially stable to extraction with water, but were unstable on incubation in 1 mM EDTA at 37°. Magnesium ions were not detected in the granules. The acidophilic and basophilic granules contained, respectively, 5 and 8 per cent of the protein present in the whole homogenate. Extensive hormone studies showed that growth and lactogenic hormones were associated with the acidophilic granules, while thyroid-stimulating hormone and gonadotropin were associated with the basophilic granules. ACTH was not present in significant amounts in either of the granule fractions, but was localized in a particulate fraction which contained microsomes and small granules. The association of the pituitary hormones with specific granules and cell types is discussed.  相似文献   

7.
The study of the changes occurring during incubation in the surface tension of the two extra-embryonic fluids of the hen''s egg has yielded results which in part harmonize with previous studies of the chemical and physical nature of these liquids, and which in part are quite inexplicable in the light of these investigations. The necessity for a more thorough chemical analysis of these fluids is clearly indicated before any exact evaluation of their significance to the developing embryo can be made.  相似文献   

8.
  1. Further purification of photosynthetic nitrite reductase (PNiR),which catalyzes the transfer of hydrogen (or electron) fromthe photolytic system to nitrite, is reported in this paper.Chromatography on DEAE- cellulose and Sephadex gel-filtrationwere effective for the purification of PNiR.
  2. PNiR could befractionated into two components. It was inferredfrom the dataobtained that one of these components is identicalwith PPNR,and the other one may probably be a hitherto unreportedflavinenzyme containing FMN as prosthetic group.
  3. The propertiesof these two components of PNiR were described,and the interrelationshipbetween these catalysts and possibleintermediary carriers ofthis electron transfer system was discussed.
1Dedicated to Prof. H. TAMIYA on the occasion of his 60th birthday.This investigation was supported by a Grant in Aid for FundamentalScientific Research from the Ministry of Education (No. 407130-1961)and a Grant in Aid for Organized Scientific Research from theMinistry of Education (No. 95037-1960), which are gratefullyacknowledged here. The authors also wish to acknowledge thatthe progress of this study was facilitated by a Grant from theKAISEI-KAI. A preliminary report on this work was read beforethe 25th Annual Meeting of the Botanical Society of Japan (1960,Osaka).  相似文献   

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10.
荒漠结皮藻类广泛分布于干旱、半干旱地区,经常面临生存水源的短缺。以一种从荒漠结皮中分离的典型绿藻-集球藻(Palmellococcus sp.)为材料,研究其在失水-吸水过程中的某些生理生化特性。即在温室模拟条件下设置相对湿度分别为0%(极度失水)、43%(适度失水)和98%(水合,对照),测定不同失水处理对集球藻光合活性、膜脂过氧化产物丙二醛含量、细胞内可溶性物质含量和抗氧化酶活性的影响,并测定蒸馏水、BBM培养基、0.2 g/L蔗糖溶液、0.2 g/L蓝藻多糖、0.2 g/L脯氨酸和2.5 mmol/L氯霉素及50μmol/L敌草隆进行吸水处理时对失水藻体光合活性的恢复效果。结果表明,与对照处理相比,集球藻在失水过程中光合活性迅速降低,SOD和CAT活性大量升高,细胞内可溶性糖含量和可溶性蛋白含量明显增加,并且膜脂丙二醛含量出现大量积累。不同的失水-吸水处理发现,外源蔗糖和胞外多糖吸水对集球藻的光合活性有较好的恢复作用,添加脯氨酸和氯霉素吸水时光合活性也获得了一定程度的恢复,采用敌草隆吸水时则出现光合活性的明显抑制。研究结果对于更好地理解荒漠结皮绿藻对干旱的生理适应机制提供了有意义的参考。  相似文献   

11.
Atomic force microscopy (AFM) is used to investigate the topography and material properties of the mucilage layer of live cells of three benthic diatoms, the marine species Crasepdostauros australis E. J. Cox and Nitzschia navis‐varingica Lundholm et Moestrup and the freshwater species Pinnularia viridis (Nitzsch) Ehrenberg. Contrary to previous studies, we show that this surface mucilage layer displays unique nanostructural features. In C. australis, tapping mode images revealed a soft mucilage layer encasing the silica cell wall, consisting of a smooth flat surface that was interrupted by regions with groove‐like indentations, whereas force measurements revealed the adhesive binding of polymer chains. The elastic responses of these polymer chains, as they were stretched during force measurements, were successfully fitted to the worm‐like chain model, indicating the stretching of mostly single macromolecules from which quantitative information was extracted. In P. viridis, tapping mode images of cells revealed a mucilage layer that had the appearance of densely packed spheres, whereas force measurements exhibited no adhesion. In N. navis‐varingica, tapping mode images of the outer surface of this cell in the girdle region revealed the absence of a mucilage layer, in contrast to the other two species. In addition to these topographic and adhesion studies, the first quantitative measurement of the elastic properties of microalgal extracellular polymeric substance is presented and reveals significant spatial variation in the C. australis and P. viridis mucilage layers. This study highlights the capacity of AFM in elucidating the topography and mechanical properties of hydrated microalgal extracellular polymeric substance on a nanoscale.  相似文献   

12.
The vacuolar surface of Nitella is covered with a non-aqueous film too thin to be visible as a separate membrane. The motion of the protoplasm may subject this film to a good deal of mechanical disturbance. Apparently this does not rupture the film for no dye escapes into the protoplasm as the result of such disturbance when the vacuolar sap is deeply stained with neutral red or brilliant cresyl blue. When the deeply stained central vacuole breaks up into several smaller vacuoles, leaving the outer protoplasmic surface in its normal position, there is no evidence of the escape of dye into the protoplasm through the film surrounding the vacuole.  相似文献   

13.
山楂粉蝶核型多角体病毒的超微结构和某些生化特性   总被引:2,自引:0,他引:2  
关书奎  张建红 《病毒学报》1991,7(4):362-368
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14.
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16.
红豆杉抗苯丙氨酸细胞系的筛选及悬浮培养特性   总被引:3,自引:0,他引:3  
通过胁迫筛选法筛选红豆杉抗-苯丙氨酸细胞变异系,并比较了该细胞系与同步培养的原型细胞系悬浮培养的几项生理指标,结果表明,抗苯丙氨酸细胞系的紫杉醇含量显著高于原型细胞系的3-5倍,并且抗性细胞系的生长速率,细胞活性,pH值,胞内可溶性糖含量及褐变强度均与原型细胞系存在显著差别。  相似文献   

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18.
我们计算了氨基酸的溶剂可接近面积,局域偶极矩及表面电场.结果显示了亲、疏水基团与水相互作用具有不同的微观本质,由此提出了新的估计氨基酸溶剂化能的方法.  相似文献   

19.
MECHANICAL PROPERTIES OF THE CELL SURFACE IN STARFISH EGGS   总被引:2,自引:2,他引:0  
The mechanical properties of the cell surface of the starfish egg at various stages of maturation have been investigated using the cell elastimeter. When constant negative pressure was applied to a part of the cell with a micropipette closely in contact with it, it bulged out, and the bulge rapidly increased at first and then gradually reached a steady value within one min. The relation between the deformation of the cell surface (i.e. degree of bulging) and applied negative pressure was almost linear in both oocytes at the germinal vesicle stage and mature eggs. The surface force and the elasticity value: i.e., the product of the elastic modulus of the surface membrane (layer) and its thickness, were determined from the relation between the deformation and the negative pressure. The elasticity value was about 5 times the surface force in both oocytes at the germinal vesicle stage and mature eggs. When maturation of the oocyte was induced by 1-methyladenine, the stiffness of the cell surface decreased shortly before the breakdown of the germinal vesicle. The stiffness transiently increased at the time of formation of the first and second polar-bodies.  相似文献   

20.
猕猴和小鼠分泌片的分离纯化及某些生化特性   总被引:1,自引:0,他引:1  
陈云亮  贲昆龙 《动物学报》1994,40(2):161-168
为了深入了解分泌片和IgA在粘膜免疫系统中的作用,自猕猴和小鼠胆汁中提取和纯化分泌片,SDS-PAGE结果表明猕猴和小鼠游离分泌片的分子量均约为60kDa,但在非解聚型聚丙烯酰胺梯度凝胶电泳时分子量分别为74kDa和62kDa。采用LKB-8100等电聚焦柱测定其PI范围,猕猴分泌片为4.3-5.9,小鼠分泌为3.9-5.4。免疫双扩散证明,猕猴和小鼠胆汁中的分泌片均能与兔抗人分泌片免疫血清发生交  相似文献   

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