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Biomedical subjects

A Elzanowski

Publications and source records attributed to A Elzanowski.

At least 19 recordsLinked to original sources
PubMed2001

Bone histology. Evolution of growth pattern in birds.

Living (neornithine) birds grow up rapidly and without interruption, terminating their growth within one year and, with a few secondary exceptions, starting to fly only after or near the completion of growth. Bone histology has revealed that pre-avian theropods also grew fast for most of the postnatal period, but that this growth was usually intermittent and probably extended for more than one year. We have found surprising evidence for an early postnatal slowing-down of growth in two lineages of flying basal birds, which suggests that birds may have started their evolution as precocious fliers.

Animals↗
PubMed1993

Interconnections of muscles in the adductor mandibulae complex of birds.

In addition to a variety of connections at or near the attachment of muscles, some of the adjacent bellies in the adductor mandibulae complex of birds merge with one another across the whole or most of their contiguous sides. Such continuous intermuscular transitions are found between the adductor posterior and the deep part of the adductor externus, the posterior adductor and quadratomandibularis muscle, the adductor posterior and pterygoideus muscle and between the quadratomandibularis and pseudotemporalis muscles. Since a complete breakup of the adductor premuscle mass occurs early in development and there is no indication of adult intermuscular transitions in any of the studied avian embryos, the muscles must coalesce at some stage of growth. Therefore, the intermuscular transitions of adult birds cannot be derived with any certainty from the primary connections in the adductor mandibulae of early gnathostomes. The coalescence of developmentally discrete muscles is invariably seamless and appears to be contingent not only upon the contiguity of muscles but also upon the congruent arrangement of their fibers.

Animals↗
PubMed1989

Homologues of catalytic domains of Cellulomonas glucanases found in fungal and Bacillus glycosidases.

We demonstrate homology between the catalytic domains of exoglucanase (1,4-beta-D-glucan cellobiohydrolase, EC 3.2.1.91) from Cellulomonas fimi and those of endoxylanases (1,4-beta-D-xylan xylanohydrolases, EC 3.2.1.8) from Bacillus sp. strain C-125 and the fungus Cryptococcus albidus; and between the catalytic domains of endoglucanase (1,4-(1,3:1,4)-beta-D-glucan 4-glucanohydrolase, EC 3.2.1.4) from Cellulomonas fimi and exoglucanase II from Trichoderma reesei. These five enzymes apparently evolved by reshuffling of two catalytic domains and several substrate-binding domains.

Actinomycetales↗