Free electron PMO:F-omega model with variable electronegativity and self-interaction correction: application to ionic reaction intermediates

1989 ◽  
Vol 187 ◽  
pp. 139-160 ◽  
Author(s):  
László von Szentpály
Author(s):  
Veronika Burmeister ◽  
N. Ludvig ◽  
P.C. Jobe

Electron microscopic immunocytochemistry provides an important tool to determine the ultrastructural distribution of various molecules in both normal and pathologic tissues. However, the specific immunostaining may be obscured by artifactual immunoreaction product, misleading the investigator. Previous observations show that shortening the incubation period with the primary antibody from the generally used 12-24 hours to 1 hour substantially reduces the artifactual immunostaining. We now extend this finding by the demonstration of artifact-free ultrastructural localization of the Ca2/calmodulindependent cyclic nucleotide phosphodiesterase (CaM-dependent PDE) immunoreactivity in brain.Anesthetized rats were perfused transcardially with phosphate-buffered saline followed by a fixative containing paraformaldehyde (4%) and glutaraldehyde (0.25%) in PBS. The brains were removed, and 40μm sections were cut with a vibratome. The sections were processed for immunocytochemistry as described by Ludvig et al. Both non-immune rabbit serum and specific CaM-dependent PDE antibodies were used. In both experiments incubations were at one hour and overnight. The immunostained sections were processed for electron microscopic examination.


Author(s):  
Jeff Gelles

Mechanoenzymes are enzymes which use a chemical reaction to power directed movement along biological polymer. Such enzymes include the cytoskeletal motors (e.g., myosins, dyneins, and kinesins) as well as nucleic acid polymerases and helicases. A single catalytic turnover of a mechanoenzyme moves the enzyme molecule along the polymer a distance on the order of 10−9 m We have developed light microscope and digital image processing methods to detect and measure nanometer-scale motions driven by single mechanoenzyme molecules. These techniques enable one to monitor the occurrence of single reaction steps and to measure the lifetimes of reaction intermediates in individual enzyme molecules. This information can be used to elucidate reaction mechanisms and determine microscopic rate constants. Such an approach circumvents difficulties encountered in the use of traditional transient-state kinetics techniques to examine mechanoenzyme reaction mechanisms.


1983 ◽  
Vol 44 (C1) ◽  
pp. C1-385-C1-385
Author(s):  
E. D. Shaw ◽  
R. M. Emanuelson ◽  
G. A. Herbster

1983 ◽  
Vol 44 (C1) ◽  
pp. C1-371-C1-371 ◽  
Author(s):  
J. C. Goldstein ◽  
W. B. Colson ◽  
R. W. Warren

1983 ◽  
Vol 44 (C1) ◽  
pp. C1-367-C1-367
Author(s):  
W. Becker ◽  
J. K. McIver

2020 ◽  
Vol 23 (1) ◽  
pp. 66-71
Author(s):  
E. A. Gurnevich ◽  
I. V. Moroz

The Smith-Purcell radiation of a charged particle moving in a periodic structure is analysed theoretically. The considered structure consists of two planar diffraction gratings with different periods which are formed by parallel conducting wires. The analytical expression for the spectral-angular distribution of radiation is obtained. It is shown that the angular distribution of radiation can be made narrower by using two gratings instead of one, and radiation intensity can be manipulated by parallel relative shift of gratings. The obtained results are of great importance for the research and development of high power radiation sources based on volume free-electron lasers.


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