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采用复性电泳方法研究了金鱼组织器官蛋白水解酶及个体发生过程中蛋白水解酶的种类和活性变化,主要结果表明:⑴金鱼各组织器官蛋白水解酶种类差异不大,大多数组织器官都具有113、69、20、16kD四条带,但不同组织器官常具有其特异性蛋白水解酶;肠道蛋白水解酶种类最多、活性最强。⑵蛋白水解酶的活性受pH值影响和制约,大多数组织器官蛋白水解酶活性最适pH值为8.5。⑶在金鱼胚胎发育早期(从卵裂到心跳期)多数  相似文献   

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从正常人不同发育时期, 不明原因流产, 增殖型和侵蚀型葡萄胎滋养细胞角度, 用免疫组织化学方法观察层粘连蛋白(LN) 的显微定位, 比较研究其不同定位与滋养上皮增殖, 生长, 分化, 凋亡, 迁移和浸润的关系。结果显示: 正常人不同发育时期, LN主要在早孕滋养细胞基底膜呈阳性着色, 中期无合体结处滋养细胞基底膜呈阳性着色; 不明原因流产,LN在合体滋养细胞质和顶尖部呈阳性着色; LN 在增殖型葡萄胎滋养细胞接触处呈阳性着色; LN 在侵蚀型葡萄胎滋养细胞膜呈阳性着色。提示:LN基底膜定位与滋养细胞分化和迁移密切相关,LN 胞膜定位与滋养上皮侵蚀密切相关,LN 细胞接触处定位与滋养细胞增殖可能相关, LN 胞质和顶尖部定位与滋养细胞凋亡可能相关, LN阴性着色与合体结和足月滋养细胞衰老可能无关  相似文献   

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Endogenous and succinic dehydrogenase activity was demonstrated in the living cells of normal human blood and bone marrow using a buffered nitro BT-succinate incubating solution. With this technique dehydrogenase activity was localized primarily in the granular leukocytes and the sites of enzymatic activity appeared to be non-mitochondrial. The addition of a non-ionic surface active agent to the incubating solution resulted in marked differences in the cellular and intracellular localization of dehydrogenase activity. With this method it was possible to demonstrate dehydrogenase activity in the mitochondria of most of the formed elements of the blood and bone marrow, including developing granulocytes and erythroid cells, agranulocytes, and blood platelets. Mature erythrocytes also exhibited a minimal dehydrogenase reaction with this procedure. This investigation indicated that in order adequately to demonstrate and evaluate dehydrogenase activity in the cells of the blood and bone marrow it was necessary to have increased cellular and mitochondrial permeability, as well as partially viable cells with an intact dehydrogenase system.  相似文献   

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《Ibis》1959,101(3-4):368-373
The anting movements of nine passerine species were studied in captivity and in the wild. The birds applied acid-spraying Formicine ants (genera Lasius and Formica ) to the plumage with the bill, with one wing extended and the tail brought round and often pressed against the wing.
Only the Magpie deliberately applied the ants both to the tail and wing. In the Song Thrush, Blackbird, Starling, Western White-eye and Blue Tit, application was to the wing-tip alone, while the Pekin Robin, Black-chinned Yuhina and old-world Robin treated the wing-tip and also, incidentally, that part of the tail held close to it. The direct result of this behaviour is the anointing of the wing-tip with formic acid, the posturing of the tail facilitating this by making the wing-tip rigid.
Anting is, apparently, one of the "feather maintenance" activities (preening, oiling, bathing, dusting, sunning) and, in the Pekin Robin and Song Thrush at least, the movements used in applying preen-oil to the wing-tip are very similar to, and probably homologous with the anting movements.
Formic-acid possibly supplements the natural preen-oil but the exact function of the anointing remains to be discovered.  相似文献   

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Nanda , K. K. (Forest Res. Inst., Dehra Dun, India.) The emergence and development of branches in Crotalaria juncea and their relationship to flowering. Amer. Jour. Bot. 49(4): 334–341. Illus. 1962.—Seeds of Crotalaria juncea L. were sown in pots on March 23, 1959, and records were kept of the dates of emergence of individual branches and the appearance of flower buds on them. Periodical observations were also made of the height of the main shoot as well as its branches and the number of nodes and leaves borne by them throughout the year. The main shoot elongates rapidly and terminates in an inflorescence. Development of lateral buds remains completely arrested during the period of rapid elongation and is initiated only after the appearance of the floral buds when it takes place in basipetal sequence. The flowering of the branches also takes place in a basipetal manner. This mode of emergence of branches and their flowering are exhibited even by secondary and tertiary branches. The length attained by these branches is very small as the flower buds appear soon after their emergence. In contrast, the branches formed towards the middle of May continue to elongate for a considerable period and become many times longer than the main shoot or the branches produced earlier in the season. The vegetative period of these branches is also very much prolonged. These differences in the height attained by branches produced at different times of the year and the basipetal sequence in the emergence of branches and their flowering appear to be under the control of some physio-chemical changes which cause the transformation of the growing apex from the vegetative to the reproductive state. This holds good irrespective of whether these changes are brought about as a result of a favorable environmental complex, as is the case with the main shoot and late-formed, much elongated branches, or are due to the favorable internal conditions produced within the plant as a result of the completion of the developmental process of the main shoot, as happens in the case of branches produced earlier in the season.  相似文献   

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The fine structure of desmosomes and intercalated discs in the toad heart is discussed. A definite relationship between the dense components of these structures and the dense region of the Z band is demonstrated. The dense region of the Z band characteristically widens at its approach to the plasma membrane, and often terminates beneath it in a distinct discoidal plaque. Cardiac desmosomes appear to be structures which result from the intimate apposition of plaques of Z band material. These desmosomes retain the Z band function as sites of attachment for myofilaments. The suggestion is made that rotation of a desmosome through 90° and splitting of filaments from the adjacent sarcomere could result in the formation of a simple step-like intercalated disc. Intermediate stages in this process are illustrated. Complex discs present in the toad probably represent the alignment of groups of simple discs produced by contractile forces. Possible physiologic functions of the disc and desmosome are discussed. Other morphologic features of toad cardiac cells include a distinct amorphous outer coat to the sarcolemma, a prominent N band, and a granular sarcoplasm with poorly developed reticulum.  相似文献   

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Abstract— An enzymatic assay was used to measure the concentration of octopamine in tissue of cephalopods. The concentration of octopamine varied over a wide range in neural tissues of Octopi and other cephalopods. The administration of reserpine caused a fall in the concentration of octopamine while monoamine oxidase inhibition caused the concentration to rise. After density gradient centrifugation octopamine was found in the same regions of the gradients as were dopamine and noradrenaline. These findings suggest that octopamine may be involved in neuronal function in cephalopods.  相似文献   

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Swiss Albino mice received a single i.v. injection of 3H-thymidine (TdR) or of 125I-deoxyuridine (IUdR). Bone marrow, thymus, spleen and mesenteric lymph node were examined for the efficiency of precursor incorporation into DNA, and for DNA renewal from day 1 to day 8.
TdR is 5–8 times more efficiently incorporated by the different organs in vivo and in vitro than is IUdR. This indicates that the discrimination against IUdR occurs at the level of DNA synthesizing cells.
A diminished DNA turnover rate measured with 3H-TdR in comparison with 125I-UdR is interpreted to indicate reutilization of TdR.
TdR reutilization was observed in bone marrow and spleen from at least day 1 on, and in the thymus from day 3 on, following pulse labeling of DNA synthesizing cells. The degree of TdR reutilization appears higher in the thymus (67%) than the bone marrow (43%) and spleen (38%). The mesenteric lymph node indicates either no, or a very low efficiency of TdR reutilization. The data are also consistent with a reutilization equally efficient for TdR and IUdR.
It is suggested that the TdR salvage pathway in hemopoietic tissues is largely localized to single organs which have immediate access to TdR made available by catabolism of DNA. The contribution of TdR from systemic reutilization to the organs studied falls within the limits of error of measurements. Moreover, the TdR salvage pathway especially in the lymph node may involve other DNA breakdown products than nucleosides.  相似文献   

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TAXONOMY AND RELATIONSHIP IN THE GERANIALES IN THE LIGHT OF THEIR CYTOLOGY   总被引:1,自引:1,他引:1  
E. F. WARBURG  Ph  .D. 《The New phytologist》1938,37(2):130-159
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Small particles (100 to 300 A in diameter) are seen in sections of nucleoli, the loops of the amphibian lampbrush chromosomes, and the Balbiani-ring regions of dipteran salivary-gland chromosomes. All of these structures contain cytochemically demonstrable RNA. Furthermore, the annuli seen on the nuclear envelope are composed of small particles which are similar to or identical with those commonly associated with the endoplasmic reticulum. It seems likely that ribonucleoproteins are organized as small particulates in the nucleus as well as in the cytoplasm.  相似文献   

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1. It has previously been shown by the author and many others that growth, in animals and plants, is an autocatalysed process. In animals it is usual to find that growth occurs in several superimposed autocatalytic cycles. In many cases, in plants and animals, especially if the cycle is one which occupies a large proportion of the growing period, it is found that the velocity-constant of the autocatalysed monomolecular formula falls off as growth proceeds, at first rapidly and later more slowly. 2. It has previously been shown by the author that the fall of the velocity-constant of growth, in the white mouse, is directly proportional to the fall of the nucleo-cytoplasmic ratio, determined by the chemical method of Le Breton and Schaeffer. If we assume this relationship to be generally applicable to the growth of animals and plants, then the following additional conclusions may be deduced, without calling in the aid of any other assumption:— 3. The increase of cytoplasm in any given cycle of growth is proportional to the concurrent increase of nuclear material. 4. The growth of cytoplasm takes place in accordance with a monomolecular formula in which the velocity-constant varies directly as the mass of the nucleus. If we superadd to these facts and deductions the hypothesis that each growth-cycle represents the growth of a separate group of cells within the animal, then the additional conclusions follow:— 5. That the cells which participate in the growth composing any cycle have initially lower nucleo-cytoplasmic ratios than the cells which participated in the preceding cycles. 6. That cells of large nucleo-cytoplasmic ratios in a multicellular animal inhibit the growth of cells which possess smaller ratios. 7. These conclusions collectively imply that the nucleus plays a predominant role in determining the development of the cell in which it resides.  相似文献   

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为在闭环条件下测得正常人的动脉压力感受器反射的开环增益(G),利用三个不同特点的血压调节模型,导出了G的计算表达式及G与血液动力学变量间的关系。用所导出的公式,通过适当的实验设计,便可近似地分别计算出颈动脉窦和主动脉弓压力感受器反射的开环增益。文中给出了计算的例子。此外,还利用导出的关系式分析了心率、外周阻力的调节变化对系统开环增益的相对贡献及输入压力水平对增益效果的影响。  相似文献   

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研究细胞间隙连接蛋白基因43(connexin43,CX43)及其蛋白、雌激素受体(estrogen receptor,ER)、孕激素受体(progesterone receptor,PR)在子宫平滑肌瘤中的表达,从核酸及蛋白水平探讨在子宫平滑肌瘤发生中的相关关系。应用核酸原位杂交技术和SP免疫组织化学法,研究37例子宫平滑肌瘤、20例正常子宫平滑肌组织中cx43mRNA及其蛋白、ER、PR的表达规律。结果显示,cx43mRNA及其蛋白、ER、PR在子宫平滑肌瘤中的表达明显高于在子宫平滑肌组织中的水平,差异有显著性(P<0.05)。cx43mRNA及其蛋白在子宫平滑肌瘤中的过度表达,是子宫平滑肌瘤发生过程的重要事件,与ER、PR水平升高呈现一致性,对进一步揭示子宫平滑肌瘤的复杂分子机制、寻求可靠的早期标志有重要意义。  相似文献   

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