Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Key words: Carbamoyltransferases — ATCase — OTCase — Protein evolution — Gene duplication — Paralogous proteins — Last universal common ancestor — Molecular phylogeny  (1)
  • limit analysis  (1)
Source
Material
Years
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    The Evolutionary History of Carbamoyltransferases: A Complex Set of Paralogous Genes Was Already Present in the Last Universal Common Ancestor (1999)
    Springer
    Journal of molecular evolution 49 (1999), S. 461-473 
    Details
    ISSN: 1432-1432
    Keywords: Key words: Carbamoyltransferases — ATCase — OTCase — Protein evolution — Gene duplication — Paralogous proteins — Last universal common ancestor — Molecular phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. Forty-four sequences of ornithine carbamoyltransferases (OTCases) and 33 sequences of aspartate carbamoyltransferases (ATCases) representing the three domains of life were multiply aligned and a phylogenetic tree was inferred from this multiple alignment. The global topology of the composite rooted tree (each enzyme family being used as an outgroup to root the other one) suggests that present-day genes are derived from paralogous ancestral genes which were already of the same size and argues against a mechanism of fusion of independent modules. A closer observation of the detailed topology shows that this tree could not be used to assess the actual order of organismal descent. Indeed, this tree displays a complex topology for many prokaryotic sequences, with polyphyly for Bacteria in both enzyme trees and for the Archaea in the OTCase tree. Moreover, representatives of the two prokaryotic Domains are found to be interspersed in various combinations in both enzyme trees. This complexity may be explained by assuming the occurrence of two subfamilies in the OTCase tree (OTC α and OTC β) and two other ones in the ATCase tree (ATC I and ATC II). These subfamilies could have arisen from duplication and selective losses of some differentiated copies during the successive speciations. We suggest that Archaea and Eukaryotes share a common ancestor in which the ancestral copies giving the present-day ATC II/OTC β combinations were present, whereas Bacteria comprise two classes: one containing the ATC II/OTC α combination and the other harboring the ATC I/OTC β combination. Moreover, multiple horizontal gene transfers could have occurred rather recently amongst prokaryotes. Whichever the actual history of carbamoyltransferases, our data suggest that the last common ancestor to all extant life possessed differentiated copies of genes coding for both carbamoyltransferases, indicating it as a rather sophisticated organism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00006569
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Computational limit analysis of rigid-plastic bodies in plane strain (1993)
    Springer
    Acta mechanica solida Sinica 6 (1993), S. 341-348 
    Details
    ISSN: 0894-9166
    Keywords: limit analysis ; mathematical programming ; finite element method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract This paper deals with the computational methods for limit analysis of plane strain problems. The finite element mathematical programming formula (FE-MPF) for determining the upper bound load multiplier established by the authors earlier is adopted and modified for plane strain problems. The penalty method is used to impose the incompressibility constraint. The FE-MPF is solved by a direct iteration procedure without the need of a searching process. This algorithm is not sensitive to the volumetric locking effect. And it can be easily extended to the limit analysis of three dimensional problems. The results of numerical examples are satisfactory and show the stable convergency of the present algorithm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02208020
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...