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At least 55 records · Page 3Linked to original sources
PubMed1984

The problem of transition from the chemical to the biological evolution: some possible solutions.

On the basis of evidence that several low-molecular-weight substances as well as enzymes are compartmentalised within the so-called soluble phase of the cell, and other considerations, it is argued that DNA may not contain information for certain types of organisation found in living cells. It may be necessary for a cell to possess the "non-DNA-controlled" organisation for performance of its minimum functions; such organisation would then also serve as a "template" for its appearance in the daughter cell. The problem of transition from chemical to biological evolution (that is, the formation of the "first cell") may be essentially the problem of emergence of such intracellular organisation for which information may not reside in DNA. Two possible mechanisms through which this may have happened are stated.

Animals↗
PubMed2004

Solvable biological evolution model with a parallel mutation-selection scheme.

Based on the connection between a quantum spin model and an asexual biological evolution model with a single-peak fitness function in parallel mutation-selection scheme, we solve exactly both static and dynamics of the evolution model. We find that relaxation in such a parallel scheme is faster than that in a connected scheme of Eigen model. Our method can also be extended to other fitness functions.

Journal Article↗
PubMedDate not supplied

Relationships between specialized cells, capillaries and intermediary cytofibrillary elements. Xth Note. Biological evolution of the emonctory subsystem and stereotype in invertebrates.

The paper points out the importance of homeostasis as the most general system of the organism (Ist order system) and the 2nd order subsystem which composes it, discussing the relations between them and the biological evolution of the emonctory subsystem in protists and invertebrates. The emonctory structures, functions and stereotype and their component parts are studied in protists, spongia, coelenterata and coelomata: lower worms, annelids, their hyponeurian descendents (arthropods, molluses) and epineurian descedents echinoderms and protochordates (Stomochordata, Tunicata, Cephalochordata). The structure, functions and stereotypes of protonephridia and metanephridia and of substitutive (vicarious) emonctory organs (nephrocytes and peritoneal cells) are studied in coelomatic invertebrates. Their evolution appears to be directioned to localize within the limits of the emonctory subsystem. During their evolution, some nephridial functions are performed by the vicarious emonctory organs. The evolution of the subsystem in invertebrates appears to be based on stable characters and their relationships with variable features.

Animals↗
PubMed1988

The biological evolution of the Leeds-Keio ligament in the human knee. A histological and ultrastructural study.

The authors report their experience in the reconstruction of the anterior cruciate ligament using the Leeds-Keio ligament in 12 patients, 7 by open arthrotomy and 5 by an arthroscopic technique. The biological evolution of the new ligament was studied macroscopically and histologically in the first 6 cases treated by open arthrotomy. Arthroscopic monitoring and biopsy was carried out 4 to 10 months after operation. In 5 cases the new ligament appeared to be intact and histologically vital, with proliferation of new tissue along the new ligament. There were broken filaments of dacron hanging from the intercondylar cavity in only one case. The first macroscopic, histological and ultrastructural results show that despite a few limitations the Leeds-Keio ligament has the features required for replacement of the anterior cruciate ligament, although it will be necessary to wait 4 or 5 years before fully evaluating the durability and function of the ligament and the best operative method.

Adolescent↗
PubMed2001

Conservation of the basic pattern of cellular amino acid composition of archaeobacteria during biological evolution and the putative amino acid composition of primitive life forms.

Previous studies showed that the cellular amino acid composition obtained by amino acid analysis of whole cells, differs such as eubacteria, protozoa, fungi and mammalian cells. These results suggest that the difference in the cellular amino acid composition reflects biological changes as the result of evolution. However, the basic pattern of cellular amino acid composition was relatively constant in all organisms examined. In the present study, we examined archaeobacteria, because they are considered important in understanding the relationship between biological evolution and cellular amino acid composition. The cellular amino acid compositions of Archaeoglobus fulgidus, Pyrococcus horikoshii, Methanobacterium thermoautotrophicum and Methanococcus jannaschii differed slightly from each other, but were similar to those determined from codon usage data, based on the complete genomes. Thus, the cellular amino acid composition reflects biological evolution. We suggest that primitive forms of life appearing on earth at the end of prebiotic evolution had a similar-cellular amino acid composition.

Amino Acids↗