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121.
The differentiation of mammalian urothelium culminates in the formation of asymmetrical unit membrane (AUM). Using gradient centrifugation and detergent wash, we purified milligram quantities of AUMs which, interestingly, contained three major proteins (15, 27, and 47 kDa) that appeared to be identical to the three immunoaffinity purified, putatively AUM-associated proteins that we described earlier (Yu, J., Manabe, M., Wu, X.-R., Xu, C., Surya, B., and Sun, T.-T. (1990) J. Cell Biol., 111, 1207-1216). Peptide mapping and immunoblotting established that these three proteins were distinct molecules. Using monospecific antibodies to these three proteins, we showed that they were all restricted to the superficial urothelial cells and were AUM-associated. The 27- and 15-kDa proteins were detected exclusively on the luminal side of mature, apical AUMs. In contrast, epitopes of the 47-kDa protein were detected on both sides of apical AUMs suggesting a transmembranous configuration. These results (i) provide the strongest evidence thus far that AUM contains three major proteins (the 27-kDa uroplakin I, 15-kDa uroplakin II, and 47-kDa uroplakin III) which form an extremely insoluble complex, (ii) suggest that uroplakin II, like uroplakin I (Yu, J., Manabe, M., Wu, X.-R., Xu, C., Surya, B., and Sun, T.-T. (1990) J. Cell. Biol. 111, 1207-1216), translocates from one side of the membrane to another during AUM maturation, (iii) indicate that uroplakin III may play a different structural role than uroplakins I and II in AUM formation, and (iv) establish the three uroplakins as markers for an advanced stage of urothelial differentiation.  相似文献   
122.
Do benzodiazepines bind at adenosine uptake sites in CNS?   总被引:6,自引:0,他引:6  
P H Wu  J W Phillis  A S Bender 《Life sciences》1981,28(9):1023-1031
Benzodiazepines inhibit adenosine uptake into rat cerebral cortical synaptosomes and their potency as inhibitors of adenosine uptake is closely correlated with therapeutic efficacy. Agents which possess “benzodiazepine like” activities such as CL218,872, zopiclone and fominoben and which displace benzodiazepine binding to brain cell membranes, are also inhibitors of adenosine uptake into brain synaptosomes. The IC50 values of all these compounds as inhibitors of adenosine uptake are in close agreement with the IC50 values obtained for the displacement of benzodiazepine binding to the brain receptors. Adenosine uptake inhibitors (dipyridamole, hexobendine, papaverine, 6-(2-hydroxy-5-nitrobenzyl)thioguanosine) which competitively inhibit adenosine uptake, presumably by blocking adenosine binding to its carrier-protein, are competitive inhibitors of diazepam binding to the brain membrane receptors. The finding of a pronounced correlation between inhibition of benzodiazepine binding and inhibition of adenosine uptake further supports the proposal that benzodiazepines may exert part of their pharmacological action through the inhibition of adenosine uptake.  相似文献   
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124.
A new method is described for the immobilization of enzymes and other proteins onto hydrophobic gels. Trypsin, for example, can be quantitatively immobilized by reaction with sodium cyanoborohydride and dodecyladehyde-coated Octyl-Sepharose. Noncovalent interactions between the hydrophobic gel and approximately 10 resulting dodecylamino groups in the modified enzyme bind it very strongly but do not affect its ability to hydrolyze benzolarginine ethyl ester. The same procedure can also be used to immobilize E. Coli asparaginase and yeast alcohol dehydrogenase in high yield.  相似文献   
125.
Mechanism of lethal action of 2,450-MHz radiation on microorganisms.   总被引:1,自引:0,他引:1  
Various bacteria, actinomycetes, fungi, and bacteriophages were exposed to microwaves of 2,450 +/- 20 MHz in the presence and in the absence of water. It was found that microorganisms were inactivated only when in the presence of water and that dry or lyophilized organisms were not affected even by extended exposures. The data presented here prove that microorganisms are killed by "thermal effect" only and that, most likely, there is no "nonthermal effect"; cell constituents other than water do not absorb sufficient energy to kill microbial cells.  相似文献   
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127.
Probabilities of occurrence for a number of the symmetries and other sequence regularities found in DNA-protein interaction site sequences have been calculated for segments of random DNA sequence. Results show that many of the symmetrical and repetitive features seen in these interaction sites are likely to have occurred by chance. Other features are so unlikely to have occurred by chance that they are probably involved in the DNA-protein interaction processes.  相似文献   
128.
In general, it is not feasible to collect enough empirical data to capture the entire range of processes that define a complex system, either intrinsically or when viewing the system from a different geographical or temporal perspective. In this context, an alternative approach is to consider model transferability, which is the act of translating a model built for one environment to another less well‐known situation. Model transferability and adaptability may be extremely beneficial—approaches that aid in the reuse and adaption of models, particularly for sites with limited data, would benefit from widespread model uptake. Besides the reduced effort required to develop a model, data collection can be simplified when transferring a model to a different application context. The research presented in this paper focused on a case study to identify and implement guidelines for model adaptation. Our study adapted a general Dynamic Bayesian Networks (DBN) of a seagrass ecosystem to a new location where nodes were similar, but the conditional probability tables varied. We focused on two species of seagrass (Zostera noltei and Zostera marina) located in Arcachon Bay, France. Expert knowledge was used to complement peer‐reviewed literature to identify which components needed adjustment including parameterization and quantification of the model and desired outcomes. We adopted both linguistic labels and scenario‐based elicitation to elicit from experts the conditional probabilities used to quantify the DBN. Following the proposed guidelines, the model structure of the general DBN was retained, but the conditional probability tables were adapted for nodes that characterized the growth dynamics in Zostera spp. population located in Arcachon Bay, as well as the seasonal variation on their reproduction. Particular attention was paid to the light variable as it is a crucial driver of growth and physiology for seagrasses. Our guidelines provide a way to adapt a general DBN to specific ecosystems to maximize model reuse and minimize re‐development effort. Especially important from a transferability perspective are guidelines for ecosystems with limited data, and how simulation and prior predictive approaches can be used in these contexts.  相似文献   
129.
Aging is a major risk factor for many diseases,especially in highly prevalent cardiopulmonary comorbidities and infectious diseases including Coronavirus Diseas...  相似文献   
130.
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