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1.
The present state of the theory of activity (by which we mean the concept developed by Leont'ev and his school) undoubtedly deserves serious discussion. Such a discussion must not be reduced, as often happens, to a critique of this theory by representatives of other schools and currents in psychology that are based on different theoretical positions (i.e., to a criticism from without), on the one hand, or to an unconditional acceptance of all of its postulates by proponents of this theory, on the other. In my view, the kind of critique of this theory that is most relevant and acutely necessary in terms of both its prospects of development and the extent to which its perceptions accord with other psychological currents is of another sort, namely, a critique from within, by which I mean analysis of its own laws, of the internal logic of development of the theory, and of its internal contradictions, which define its present status and the dynamics of its development. Such an analysis should enable us to stimulate more effectively the internal mechanism of development and self-development of the theory of activity and ensure a transition from a period of stagnation that has produced nothing of note to a progressive evolution of its content and its explanatory power.  相似文献   

2.
南瓜果肉色素的提取及稳定性的研究   总被引:5,自引:0,他引:5  
本文研究了从南瓜果肉中提取色素的方法,并对它的光、热、酸、碱稳定性进行了研究,发现其性质较稳定,且原料来源广泛,提取工艺简单,着色效果好,是食品、医药、化妆品等领域的理想添加剂。  相似文献   

3.
As revealed in animal experiments, glucosaminylmuramyl dipeptide (GMDP), the synthetic analog of muramyl dipeptide, when introduced intraperitoneally in a single injection or orally, exhibits adjuvant activity with respect to Citrobacter 0-antigens, Shigella flexneri and enhances the protective properties of dysentery and pertussis vaccines. The stimulating properties of GMDP depend on its dose, the route of its administration, the time elapsed after its administration, its ratio to the concomitant doses of bacterial antigens and to the dose of the virulent culture used for challenge.  相似文献   

4.
During intrauterine life microcirculatory bed of the muscular coat is forming and developing in accordance with its differentiation, growth and functional changes at various steps of its ontogenesis. This step-like differentiation in the parts composing the microcirculatory bed and the whole microcirculatory network of longitudinal and circulatory layers of the muscular coat is genetically connected with differentiation taking place in the wall of the sigmoid colon during the developmental period studied and, in the end, reflects morphological maturation of the sigmoid colon at different stages of its individual ontogenesis.  相似文献   

5.
The response of a red blood cell (RBC) to deformation depends on its membrane, a composite of a lipid bilayer and a skeleton, which is a closed, twodimensional network of spectrin tetramers as its bonds. The deformation of the skeleton and its lateral redistribution are studied in terms of the RBC resting state for a fixed geometry of the RBC, partially aspirated into a micropipette. The geometry of the RBC skeleton in its initial state is taken to be either two concentric circles, a references biconcave shape or a sphere. It is assumed that in its initial state the skeleton is distributed laterally in a homogeneous manner with its bonds either unstressed, presenting its stress-free state, or prestressed. The lateral distribution was calculated using a variational calculation. It was assumed that the spectrin tetramer bonds exhibit a linear elasticity. The results showed a significant effect of the initial skeleton geometry on its lateral distribution in the deformed state. The proposed model is used to analyze the measurements of skeleton extension ratios by the method of applying two modes of RBC micropipette aspiration.  相似文献   

6.
Abstract

In contrast to the huge amount of research on Turkish migration and migrants, the diasporic politics of the Turkish Kemalist state constitutes a neglected research subject in the scholarship on Turkish diaspora. How does the Turkish state reach out to its nationals and expatriates abroad? In what ways does the Turkish Republic seek to make Islam (as it does in Turkey) into an instrument legitimizing its politicizing and mobilizing enterprises? To explore these questions, this article investigates the long-distance Kemalism engaged in by the Turkish state to Turkify and secularize its nationals in the diaspora, using its activities in Australia as its case study. In sketching out trans-Kemalism's dimensions, the analysis directs attention to the intimate relationship between the political and religious fields of transnationalism manufactured by the state. The paper concludes that the intense political polarization in Turkey in the present makes the future of trans-Kemalism abroad somewhat uncertain.  相似文献   

7.
Abstract

Determination of tautomeric population of the Y-base in 3 by 13C-NMR spectroscopy has shown that its most thermodynamically preferred tautomeric form is the N1-H tautomer (~ 95 %) which explains its chemical reactivity in glycosylation reaction and also in the facile, lewis acid promoted isomerization of wyosine-2′,3′,5-O-triacetate 5 to its N1-isomer 4. It is likely that the consequence of occurrence of natural wyosine in the thermodynamically unfavoured N3-form is its unusual lability across the glycosyl bond under mild acidic conditions.  相似文献   

8.
Reoxidation of the disulfide bonds of the alpha-subunit of human choriogonadotropin after their complete reduction yields a product which is indistinguishable from the native subunit in its electrophoretic pattern in polyacrylamide gel and in its ability to recombine with the beta subunit of bovine lutropin. The circular dichroism of reoxidized human choriogonadotropin-alpha is essentially identical to that of the native alpha-subunit, except for slightly more negative ellipticity in the region of 240 mm. Hybrid hormone preparations obtained by recombination of reoxidized or native human choriogonadotropin-alpha with native lutropin-beta exhibit identical electrophoretic patterns in polyacrylamide gels, elution profiles in gel filtration, receptor binding activities, and CD spectra. However, reoxidation of human choriogonadotropin-beta under the same conditions does not yield a product which resembles the native beta subunit in its electrophoretic pattern on gels, its CD spectrum or its ability to recombine with the alpha subunit.  相似文献   

9.
The major form of the trypsin-like proteinases from the larvae of the webbing clothes moth Tineola bisselliella has been further purified and some of its properties investigated. It differs from bovine trypsin in several respects. It is anionic at neutral pH, is very stable at alkaline pH, has no requirement for calcium ions for this stability and is very sensitive to urea. It resembles vertebrate trypsins in its complete inhibition by diisopropylfluorophosphate, its pH optimum of 8.5 for hydrolysis of benzoyl-arginine p-nitroanilide and its cleavage specificity against glucagon and the beta-chain of S-carboxymethyl insulin.  相似文献   

10.
The authors show the use of Electro-Immuno-Diffusion on cellulose acetate in the diagnosis of Farmer's lung. This technique with its simplicity, its rapiditity, its sensibility is an interesting routine method in the detecting of this disease.  相似文献   

11.
The potassium orthophosphate added to the media with developing actinomycetes inhibits the nonactin macrotetrolide antibiotic but causes the increase of mycelium growth. The degree of inhibition depends on the quantity of orthophosphate and almost doesn't depend on the time of its adding to the actinomycetes culture. The degree of phosphorus consumption by actinomycetes is higher, the more its content in the media. The antibiotic synthesis takes place during the phosphorus consumption but not after its exhaustion from the media.  相似文献   

12.
Glucagon is considered for mechanisms of its action on the carbon metabolism, its significance in the complex polyhormonal regulation of the glucose synthesis and metabolism being studied. Glucagon exerts its effect on cells through specific receptors arranged on the plasma membrane, while its effect on the carbohydrate metabolism is mediated, mainly, by cAMP-dependent phosphorylation os some proteins participating in regulation of carbohydrate synthesis and metabolism including the proteins controlling expression of many genes. The glucagon effect on the level and efficiency of the action of insulin and some other hormones is an important link in the glucagon action on the carbohydrate metabolism.  相似文献   

13.
14.
季朝能  张冰  姜涛  盛小禹  毛裕民 《遗传学报》2000,27(12):1100-1107
通过对耐热碱性磷酸酯酶TAPND27活性位点S(69)两侧的E(68)和S(70)的定点突变,得到了3个突变子E68S、S70A和E68SS70A。在蛋白纯化的基础上测定了3个变体的一些酶学性质,与TAPND27相比,E68S的比活力上升8倍,Tm下降了3℃,最适反应温度上升了20℃;S70A的比活力上升了1部,Tm下降了2℃,最适反应温度上升了5℃;E68SS70A的比活力下降了50%,Tm下降  相似文献   

15.
The movement protein (MP) of the tobacco mosaic virus (TMV) provides the intercellular transport of the viral RNA through plasmodesmata. MP fulfils its function while interacting with host cell factors on the whole way of its intracellular movement from the subcellular site of its synthesis to the plasmodesmata of cellular walls. The MP conformation during its intracellular movement and fulfilling the transport function still remains unknown. In this study, we describe the preparation of murine monoclonal antibodies (MAs) to TMV MP and mapping of the MP epitopes. Stable hybridoma lines that produce MAs to the partially denatured recombinant MP (MPr) were obtained. MAs were tested by the immunoblotting and ELISA with the use of deletion variations of MPr. The epitopes of TMV MPr that recognize specific MAs were determined.  相似文献   

16.
The DNA-dependent protein kinase (DNA-PK) was identified as an activity and as its three component polypeptides 25 and 15 years ago, respectively. It has been exhaustively characterized as being absolutely dependent on free double stranded DNA ends (to which it is directed by its regulatory subunit, Ku) for its activation as a robust nuclear serine/threonine protein kinase. Here, we report the unexpected finding of robust DNA-PKcs activation by N-terminal constraint, independent of either DNA or its regulatory subunit Ku. These data suggest that an N-terminal conformational change (likely induced by DNA binding) induces enzymatic activation.  相似文献   

17.
We describe in this report the presence of a nuclear localization signal (NLS) overlapping the calmodulin-binding domain (CaM-BD) of the growth factor receptor bound protein 7 (Grb7). We show that deletion of the CaM-BD of Grb7 prevents its nuclear localization, and that its Src homology 2 (SH2) domain might participate as well in the translocation process. Also, treating cells with the CaM antagonist N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) enhances the presence of Grb7 in the nucleus. We propose that CaM inhibits the translocation of Grb7 to the nucleus after binding to its CaM-BD and therefore occluding its overlapping NLS.  相似文献   

18.
An analysis of the S1/S1d mouse for ferrokinetics and fate of peripheral red blood cells has shown the cause of its anemia to be dual in nature. While the S1/S1d produces red cells at a slightly greater rate than its normal littermate, its bone marrow and spleen appear to be operating near their maximal capacity and will reduce their output if anemic stress is partly relieved. The cause of the moderately high level of erythropoiesis in the S1/S1d is a mean daily loss of 2.5--3.0% of its total blood volume via the intestinal tract.  相似文献   

19.
Satiety: the roles of peptides from the stomach and the intestine   总被引:1,自引:0,他引:1  
Rats were surgically prepared to allow perfusions of anatomically limited portions of the gastrointestinal (GI) surface during test meals. The results demonstrated that at least one potent satiety signal was generated when ingested food accumulated in the stomach and did not enter the small intestine. This gastric satiety signal did not require the vagus nerve for its operation. In addition, at least one other potent satiety signal was generated when food perfused the small intestine. This intestinal satiety signal did not require gastric distension for its operation. We tested a variety of GI peptides to determine whether any met the criteria imposed by this evidence for regionally specific satiety signals. Bombesin (BBS), a peptide present in high concentration in the stomach, was a potent and behaviorally specific inhibitor of food intake. Its satiating effect was not altered by subdiaphragmatic vagotomy. Cholecystokinin (CCK), a peptide hormone that is released from the small intestine by food, was also a potent and behaviorally specific inhibitor of food intake; its satiating effect did not require gastric distension for its expression, but its satiating effect was markedly reduced or abolished by subdiaphragmatic vagotomy. Thus, BBS and CCK may mediate at least part of the satiating effect of food acting in the stomach and in the small intestine, respectively.  相似文献   

20.
A monospecific polyclonal antiserum to the regulatory subunit (R) of the cAMP-dependent protein kinase of Blastocladiella emersonii has been developed by immunization with purified regulatory subunit. In Western blots, the antiserum displays high affinity and specificity for the intact R monomer of Mr = 58,000, as well as for its proteolytic products of Mr = 43,000 and Mr = 36,000, even though the antiserum has been raised against the Mr = 43,000 fragment. Western blots of cell extracts prepared at different times during the life cycle of the fungus indicate that the increase in cAMP-binding activity occurring during sporulation, as well as its decrease during germination, are associated with the accumulation of the regulatory subunit during sporulation and its disappearance during germination, respectively. Pulse labeling with [35S]methionine and immunoprecipitation indicate that the accumulation of R is due to its increased synthesis during sporulation. Two-dimensional gel electrophoresis of affinity purified cell extracts obtained after [35S]methionine pulse labeling during sporulation confirms de novo synthesis of R during this stage and furthermore shows that the protein is rapidly phosphorylated after its synthesis. In vitro translation studies using RNA isolated from different stages of the life cycle followed by immunoprecipitation have shown that the time course of expression of the mRNA coding for the regulatory subunit parallels the rate of its synthesis in vivo.  相似文献   

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