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Biomedical subjects

L Hirth

Publications and source records attributed to L Hirth.

At least 73 records · Page 4Linked to original sources
PubMed1976

Stucture of the amino-acid accepting 3'-end of high-molecular-weight eggplant mosaic virus RNA.

The sequence of the first 59 nucleotides from the 3'-OH terminus of high-molecular-weight eggplant mosaic virus RNA has been determined by standard radio-chemical techniques. The fragment was identified among the products of partial T1 RNase digestion by making use of the reverse migration, at pH 2.5, of the 3'-OH terminal oligonucleotide. No abnormal bases were found. A model of secondary structure may be constructed for this fragment, which is known to fix valine in the presence of valyl-tRNA synthetase. Its relation to the structures of genuine tRNAs and to the 3'-OH termini of other viral RNAs that also accept amino acids is discussed.

Amino Acids↗
PubMed1976

Physical and functional heterogeneity in TYMV RNA: evidence for the existence of an independent messenger coding for coat protein.

Turnip yellow mosaic virus RNA can be separated into two distinct components of 2 times 10(6) and 300 000 daltons molecular weight after moderate heat treatment in the presence of SDS or EDTA. The two species cannot have arisen by accidental in vitro degradation of a larger RNA, as they both possess capped 5' ends. Analysis of the newly synthesized proteins resulting from translation of each RNA by a wheat germ extract shows that the 300 000 molecular weight RNA can be translated very efficiently into coat protein. When translated in vitro the longer RNA gave a series of high molecular weight polypeptides but only very small amounts of a polypeptide having about the same mass as the coat protein. Thus our results suggest that the small RNA is the functional messenger for coat protein synthesis in infected cells.

Genetic Code↗
PubMed1976

Some properties of tobacco protoplast chromatin.

Chromatin was prepared from tobacco-leaf protoplasts. Its solubility in increasing molarities of NaCl was studied and the structure of the soluble fraction observed by electron microscopy. We demonstrate that in plants, the DNA and histones are associated in beaded structures similar to those called omicron-bodies or nucleosomes in animal chromatin. The nucleosomes were associated with DNA in either compact or extended forms. The compact arrangement was predominant in the fraction solubilized between 0.1 and 0.4 M NaCl. The extended form, present at 0.5 and 0.6 M NaCl. showed DNA filaments of various lengths interspacing the nucleosomes. At these ionic strengths ring structures were present, associated with the DNA. At 0.7 M NaCl and above, only DNA filaments were present, occasionally associated with big rings, and nucleosomes were compoetely dissociated. Free DNA molecules were present at all ionic strengths used. The possible origin and significance of the rings are discussed.

Cell Nucleus↗
PubMed1975

[Lip prints--variability and genetics (author's transl)].

In a sample of 500 persons, including 76 families with 133 children, 22 mono- and 17 dizygote twins, lip prints were prepared for the study of variability and genetical basis of ridge-pattern in the region of mucous membrane lips. Taking 4 classes of pattern with different ridge-branching as a basis we observed more frequently branched pattern at the upper lip and mainly simple pattern at the lower lip. About 30% of the lip-prints showed whirling figures--at the upper lip simple and median, at the lower lip double and paramedian. Investigations during several months showed stability against environmental factors. The results of twins, families and mother(father)-child combinations proved a genetical basis of lip-prints. Applications of cheiloscopy to genetical investigations are reported.

Adolescent↗
PubMed1975

[Cinnamic acid 4-hydroxylase and 0-methyltransferase activities in leaves of hypersensitive tobacco plants infected by tobacco mosaic virus].

Tobacco leaves of Nicotiana tabacum L., variety Samsun NN, show a low cinnamic acid-4-hydroxylase activity and a rather high O-methyltransferase activity. Caffeic acid, the substrate of the latter enzyme, is methylated specifically in the meta position. In TMV-infected leaves a strong increase in the activities of phenylalanine ammonia-lyase and of these two enzymes occurs at the time of appearance and development of the necrotic reaction.

Caffeic Acids↗