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The microneedle shuttle analysis in the determination of plant secretory system content.
No full textDistribuzione delle furanocumarine in organi ipogei di Heracleum sphondylium L. subsp. ternatum.
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The Primary Structure of Piscine (Oncorhynchus mykiss) Retinol-Binding Protein and a Comparison with the Three-dimensional Structure of Mammalian Retinol-Binding Protein
No full text1. The primary structures of two variants of rainbow trout (Oncorhynchus mykiss) plasma retinol-binding protein (RBP) were determined and found to be approximately 60% identical with those of both human and Xenopus laevis RBPs. The comparable sequence similarities that we have found agree with the estimate of similar divergence times between bony fishes and mammals and between bony fishes and amphibians. The two piscine RBP variants differ by six amino acid substitutions at positions that are not crucial for the interaction with retinol, on the basis of the human RBP three-dimensional structure [Cowan, S. W., Newcomer, M. E. & Jones, T. A. (1990) Proteins Struct. Func. Genet. 8, 44 - 61].
2. Models were developed for the three-dimensional structures of rainbow trout and X. laevis RBPs, based on that of human RBP. The overall three-dimensional structure appears to be very well preserved for RBPs isolated from vertebrate species for which the divergence time is 350 - 400 million years. At variance with an almost absolute conservation for the residues that participate in the formation of the retinol binding site in mammalian RBPs, several amino acid replacements are found for this part of the RBP molecule when the comparison is extended to piscine and amphibian RBPs. However, the only allowed amino acid replacements are either conservative or more than 0.4 nm distant from retinol. Besides the retinol binding site, a few regions at the protein surface appear to be rather conserved during phylogenetic development of vertebrates and, therefore, might be involved in molecular interactions
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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