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Biomedical subjects

W Jahn

Publications and source records attributed to W Jahn.

At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

Visualization of a ternary complex of the Escherichia coli Phe-tRNA(Phe) and Tu.GTP from Thermus thermophilus by scanning transmission electron microscopy.

Scanning transmission electron microscopy (STEM) was used to visualize formation of a ternary complex between the T. thermophilus elongation factor (EF) Tu.GTP and the Escherichia coli Phe-tRNA(Phe) labeled with an undecagold (Au11) cluster at minor nucleotide 3-(3-amino-3-carboxypropyl) uridine at position 47. The ternary complex was further characterized by the molecular mass and radius of gyration calculated from the mass distribution within the individual particles. Under conditions used for STEM imaging, the ternary complex is formed between Au11-labeled Phe-tRNA(Phe) and Tu.GTP in a yield up to 25%. The stoichiometry of EF-Tu.GTP to aminoacyl-tRNA (aa-tRNA) in the EF-Tu.GTP.aa-tRNA complex is 1:1, in agreement with the established view of the protein biosynthesis mechanism. The ternary complex is also formed, although to a lower extent, with GTP analogues (GMPPCP and GMPPNP, respectively), but not with Tu.GDP and nonaminoacylated tRNA(Phe) with Tu.GTP.

Escherichia coli↗
PubMedDate not supplied

Formation of actin clusters in rat liver parenchymal cells on phalloidin poisoning as visualized by a fluorescent phallotoxin.

By staining of cryo-sections of rat liver with a fluorescent phallotoxin, the distribution of filamentous actin in liver cells could be demonstrated by fluorescence microscopy. While no untreated livers filamentous actin forms an almost continuous layer at the cell periphery, the poisoning by phalloidin leads to the formation of actin clusters, preferentially located near the cell membrane.

Actins↗
PubMedDate not supplied

[Histomorphometric contribution to W. Beier's exponent of the aging function].

We determined aging changes of the nucleus-cytoplasm-relation in the epithelium of the epiglottis and intestine of human beings and rats. The results were compared with data about the proliferation of connective tissue and the decrease of muscle cells in the wall of the intestine and in the ciliary muscle. We adapted exponential functions to the measured results. For comparing the several equations and the derivable aging velocities, the nucleus-cytoplasm-relation must be transformed into nucleus volume rate of the total cell volume. Similarities in the decrease of the aging speed in the course of life and in the value of the exponent of the aging function by W. Beier (approximately equal to 0,03) were demonstrated.

Adult↗