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1.
观察了菠菜叶绿体类囊体膜与残缺膜的表面结构及鼠肝线粒体嵴膜小囊在制备过程中的生成过程,证明了嵴膜小囊可有两种,F_1在膜外侧或膜内侧,它们都可与残缺膜组成镶嵌膜,进行光下磷酸化功能。而F_1在膜外侧的嵴膜小囊与残缺膜的嵌合膜活力更高。 相似文献
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研究了中性红再生紫膜从先适应状态到暗适应状态的反应及再生紫膜中中性红的光吸收变化。实验结果说明紫膜上的金属离子结合位点可能深入膜内的质子通道,与构成质子通道的一些重要氨基酸残基相互作用。紫膜经去离子化处理变成蓝膜后,带有正电荷的质子化中性红也可以占据此金属离子结合位点,使蓝膜再生为紫膜。但金属离子与结合位点具有更强的亲和力,使蓝膜再生为紫膜的能力比质子化中性红强。 相似文献
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类囊体膜的垛叠、松散与它的功能关系 总被引:2,自引:0,他引:2
菠菜完整叶绿体置于4mM MgCl_2或20 mM KCl低浓度介质中低渗10秒钟后,得到由Mg~(++)或K~+离子诱导的类囊体垛叠膜和松散膜。它们在功能上表现出明显的差异。垛叠膜有较高的毫秒级延迟光发射(ms-DLE),松散膜显著降低DLE的快相,垛叠膜比松散膜的9-AA荧光猝灭快,并保持稳定;而松散膜有H~+渗漏。在非循环或Fd催化的循环光合磷酸化中,垛叠膜比松散膜活力高。但是,若在同样的低渗介质中低渗1分钟以上,Mg~(++)离子诱导的垛叠膜,在显微结构上不同于低渗过10秒钟的垛叠膜,它垛叠较松,而且在磷酸化活力上也与松散膜差别不大。揭示了H~+传递速度受二个光系统、电子载体间的距离及偶联程度的限制。新鲜制备的垛叠或松散膜,在NADP~+还原系统中,具有相同的电子传递放O_2速度,说明电子传递速度在一定范围内不受膜间的距离和偶联程度的影响。但是松散膜不稳定,随着膜的老化而解联,牛血清白蛋白(BSA)能稳定松散膜的电子传递。 相似文献
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光强与光质对银杏光合作用及黄酮苷与萜类内酯含量的影响 总被引:37,自引:0,他引:37
对2年生银杏(Ginkgo biloba L.)苗进行遮荫和光膜处理,测定光合速率及碳水化合物,银杏黄酮苷与萜类内酯的含量。光合速率在自然光下测定时从大到小依次为:黄膜>蓝膜和红膜>绿膜>紫膜和白膜,在光膜下测定时为:黄膜>红膜>蓝膜、紫膜和白膜>绿膜。光强和光质对碳水化合物含量有显著影响。光质对萜类内酯的生物合成和积累有影响,紫膜处理的银杏萜类内酯含量最高,为3.89mg/g,比白膜(对照) 高85.23%,其次是绿膜,为2.80mg/g。覆膜和蔗荫显著减少银杏黄酮苷含量,这可能与紫外辐射强度减弱有关。 相似文献
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羧甲基壳聚糖膜对皮肤成纤维细胞相容性研究 总被引:13,自引:0,他引:13
通过玻璃流延法制备不同分子质量的壳聚糖及羧甲基壳聚糖膜,以体外培养的人皮肤成纤维细胞作为对象,利用膜的浸渍液培养及膜表面直接培养法研究比较了两种多糖膜的细胞相容性.实验发现两种多糖膜的浸渍液对细胞均无毒性效应,生物安全性是小分子质量膜好于大分子质量膜,羧甲基壳聚糖膜好于壳聚糖膜.皮肤成纤维细胞在壳聚糖膜上的生长受到抑制,生长一段时间后细胞有聚集和脱落现象,而羧甲基壳聚糖膜上细胞能很好地贴附、生长,没有聚集和脱落现象.结果表明羧甲基壳聚糖膜具有比壳聚糖膜更优越的细胞相容性. 相似文献
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本文就叶绿体光合膜中主要膜脂的分子结构及其特性和在膜中的分子组装进行了综述,并指出了目前膜脂研究的趋势和存在的问题。 相似文献
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1. The method described by Elford for the preparation of graded collodion membranes suitable for ultrafiltration was found to give excellent results, and his findings are fully confirmed. 2. A formula is given for the preparation of collodion from which satisfactory membranes of graded porosity can be prepared. 3. The technique and apparatus used in the preparation, and standardization of membranes are described in detail. 4. The technique and apparatus required for ultrafiltration experiments are described, and some drawbacks encountered in the experiments are discussed. 5. The results of ultrafiltration experiments show that the pores of the membranes are remarkably uniform in size. 相似文献
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系统比较了5种不同材质滤膜对于制备溶解态微囊藻毒素的影响,发现了影响藻毒素测定样品前处理的关键操作步骤。结果表明,醋酸纤维滤膜(CA filter)最多可吸附样品中79%的藻毒素,导致测得的MCs浓度严重偏低。玻璃纤维(GF/C)滤膜和聚醚砜(PES)材质滤器对制备溶解态微囊藻毒素过程影响很小。另外,发现离心法无法完全去除野外水华样品中藻细胞,反而可能导致藻细胞破裂,释放藻毒素,影响水中溶解态微囊藻毒素的测定。研究结果将对发展水体中溶解态藻毒素测定标准方法提供依据。
相似文献
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乳杆菌制剂对非特异性阴道炎的治疗及其机制的研究 总被引:14,自引:8,他引:6
本文对32例非特异性阴道炎患者以乳杆菌进行治疗,比较用药前后阴道分泌物pH及阴道常见的乳杆菌、葡萄球菌、肠杆菌、酵母菌的定量变化,同时观察其临床治疗效果。结果表明:治疗后阴道分泌物pH明显降低,乳杆菌数量明显增多,葡萄球菌、肠杆菌、酵母菌数量明显减少。治疗后阴道炎的症状、体征明显好转。 相似文献
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本文观察了青春型双歧杆菌(Bif.a)对小鼠肝癌移植瘤的抑制作用。结果发现,青春型双歧杆菌在瘤细胞移植前或移植后应用均显示了抑制肿瘤生长的作用。将青春型双歧杆菌注入肤腔可激活肤腔巨噬细胞,提高其吞噬功能和非特异性酯酶活性,而加入体外培养的小鼠肝癌细胞未显示有杀伤瘤细胞作用。认为青春型双歧杆菌的抑瘤作用可能是该菌刺激了宿主的免疫活性细胞杀伤了瘤细胞,而非直接杀伤作用。 相似文献
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The mechanisms and pathways of synthesis of phosphatidylcholine in the giant fibre system of the squid (Loligo vulgaris) have been examined by incubating the stellate ganglion-nerve preparation or its separated compartments in an artificial bathing solution with labelled choline. Other experiments were done by dissecting the whole stellate ganglion into axoplasm, axon sheath, giant fibre lobe, small fibres and ganglion residue, after incubation. The initial rate of choline incorporation into choline phosphoglycerides was severalfold higher in the lobe than in the axon. Higher lipid radioactivity was recovered in the axon sheath as compared to the axoplasm, and in the small fibres as compared to the ganglion residue which contains its cell bodies. The production of phosphorylcholine and CDP-choline in the intact ganglion-nerve preparation during incubation with choline points to the occurrence of the net synthesis pathway for phosphatidylcholine in this material. Base-exchange activity was also observed in the axon and giant fibre lobe preparations in vitro, but no indication can yet be given whether it also takes place in intact preparations. Electrical stimulation and‘depolarizing’conditions enhance choline phosphorylation in the squid axon and lobe, but decrease phosphatidylcholine labelling. 相似文献
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THE MEASUREMENT OF TRIGLYCERIDE IN BRAIN AND THE METABOLISM OF BRAIN TRIGLYCERIDE IN VITRO 总被引:9,自引:5,他引:4
C. E. Rowe 《Journal of neurochemistry》1969,16(2):205-214
Abstract—
- 1 Triglyceride has been isolated from brain by thin-layer chromatography and determined by absorption of the carbonyl group at 1740 cm?1. The means of yields from whole mouse brain, whole rat brain, rat brain grey matter, rat brain stem, and incubated slices of rat brain cortex were 0.15–0.17 μmole/g tissue.
- 2 The distribution of fatty esters varied from preparation to preparation. Palmitate, stearate and oleate usually occurred in greatest amounts. Hydrolysis of a preparation of triglyceride from whole rat brain with pancreatic lipase indicated that palmitate was equally distributed between the α and β esters.
- 3 [1-14C]Acetate was rapidly incorporated into triglyceride of slices of incubated rat brain cortex. When the resulting triglyceride was hydrolysed with pancreatic lipase the distribution of radioactivity amongst the hydrolysis products was consistent with both the α and β esters of the triglyceride having been radioactively labelled.
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COMPARATIVE STUDIES IN SYNAPTOSOME FORMATION: THE PREPARATION OF SYNAPTOSOMES FROM THE HEAD GANGLION OF THE SQUID, LOLIGO PEALII 总被引:1,自引:0,他引:1
Abstract— Relatively high concentrations of ACh have been found in the head ganglion of the squid ( Loligo pealii ) and the identity of the ACh has been verified by ion-exchange chromatography. Following homogenization in media iso-osmotic with sea water about 40 per cent of the ACh survives in particle-bound form. Experiments using media of varying osmolarity suggest that this bound ACh is osmotically sensitive. A study has been made of the subcellular fractionation of squid head ganglion using sucrose homogenates. A rapid and novel method is described for the preparation of a synaptosome fraction freed from mitochondria. This preparation contains synaptosomes of well-preserved morphology with occluded cytoplasm and a high specific content of ACh. The synaptosomes are osmotically sensitive and when suspended in water they burst, releasing cytoplasmic constituents and ACh-containing synaptic vesicles. The synaptic vesicles can be separated from other sub-synaptic constituents by density gradient centrifugation. 相似文献
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血清胃泌素变化与急性胃粘膜病变关系的研究 总被引:6,自引:0,他引:6
吴同乐 《生物化学与生物物理进展》1992,19(2):127-130
对大白鼠血清中胃泌素水平的变化与急性胃粘膜病变的关系进行了初步的研究,结果表明以消炎痛为诱因引起的急性胃粘膜病变大白鼠血清胃泌素水平明显增高。而维酶素可以抑制因消炎痛引起的急性胃粘膜病变时血清胃泌素的释放,对胃粘膜具有保护作用。 相似文献
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A method for the preparation and examination of fragile andparticularly small (sub-millimetre) shells is presented, basedupon the geologist's method for the viewing of fine sectionedrock. (Received 19 February 1985; 相似文献