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B F Clark

Publications and source records attributed to B F Clark.

166 records · Page 10Linked to original sources
PubMedDate not supplied

Interaction between dimeric methionyl-tRNA synthetase and methionine accepting tRNAs from E. coli.-- Studies by partial ribonuclease digestion.

Using different ribonucleases we have studied the digestion pattern of the two methionine accepting tRNAs, the initiator tRNAfMet and the elongator tRNAmMet from E. coli. The positions and intensities of cleavages are compared to those obtained when the tRNAs are complexed to methionyl-tRNA synthetase. Our results, in comparison with other studies, suggest a general pattern of interaction between tRNAs and their cognate synthetases including the amino acid stem and the anticodon region. Furthermore a lack of involvement of the central region and especially the extra arm seems to be a unique feature of the initiator tRNAMetf.

Amino Acyl-tRNA Synthetases↗
PubMedDate not supplied

Distinction between differentiation and senescence and the absence of increased apoptosis in human keratinocytes undergoing cellular aging in vitro.

We have examined the processes of differentiation and apoptosis in relation to cellular aging by using a culture system based on serial passaging of monolayer cultures of human keratinocytes in a serum-free low calcium medium. Differentiation was analyzed by cellular morphology and by the expression of keratinocyte transglutaminase. Keratinocyte cultures at all passages could be induced to differentiate into mature keratinocytes by raising the calcium concentration in the medium. Differentiation could also be induced in senescent cultures, but the process was significantly slower. Apoptosis was analyzed by cellular morphology and by the expression of tissue transglutaminase. Apoptotic cells constituted a very small proportion of the culture and no detectable change in the incidence of apoptosis occurred during serial passaging.

Adult↗