Self-Referential Encoding on Modules of Anticodon Pairs-Roots of the Biological Flow System.

The proposal that the genetic code was formed on the basis of (proto)tRNA Dimer-Directed Protein Synthesis is reviewed and updated. The tRNAs paired through the anticodon loops are an indication on the process. Dimers are considered mimics of the ribosomes-structures that hold tRNAs together and facilitate the transferase reaction, and of the translation process-anticodons are at the same time codons for each other.

The Self-Referential Genetic Code is Biologic and Includes the Error Minimization Property.

The distribution of the triplet to amino acid correspondences in the genetic code matrix contains blocks of similarity. There are (a) groups of similar triplets coding for the same amino acid, which is called code degeneracy, and (b) clusters of similar amino acids corresponding to similar triplets. Processes that led to this regionalization have been investigated through a variety of perspectives but no consensus has been reached and no model has been convincing enough to drive experimental tests.

Essentials in the Life Process Indicated by the Self-Referential Genetic Code.

The self-referential genetic encoding starts with glycine and serine, in the realm of one-carbon units of metabolism. It is proposed that the prototRNA dimer-directed mechanism of protein synthesis and encoding promotes a sink dynamics that corresponds to the driving 'force' for the fixation of the supporting metabolic pathways. A succession of processes is delineated, ending up in reproduction, which accomplished the function of reinforcing the protein synthesis metabolic sink mechanism.

Essentials in the life process indicated by the self-referential genetic code.

The self-referential genetic encoding starts with glycine and serine, in the realm of one-carbon units of metabolism. It is proposed that the prototRNA dimer-directed mechanism of protein synthesis and encoding promotes a sink dynamics that corresponds to the driving 'force' for the fixation of the supporting metabolic pathways. A succession of processes is delineated, ending up in reproduction, which accomplished the function of reinforcing the protein synthesis metabolic sink mechanism.

Three-Dimensional Algebraic Models of the tRNA Code and 12 Graphs for Representing the Amino Acids.

Three-dimensional algebraic models, also called Genetic Hotels, are developed to represent the Standard Genetic Code, the Standard tRNA Code (S-tRNA-C), and the Human tRNA code (H-tRNA-C). New algebraic concepts are introduced to be able to describe these models, to wit, the generalization of the 2n-Klein Group and the concept of a subgroup coset with a tail. We found that the H-tRNA-C displayed broken symmetries in regard to the S-tRNA-C, which is highly symmetric.

Etiopathogenesis of peptic ulcer: back to the past?

Objectives: To review some aspects of the etiopathogenesis of peptic ulcerous disease especially on the basis of studies on its correlation with Helicobacter pylori (H. pylori).

Methods: A search was made in the data bases MEDLINE, LILACS and PubMed, and in Brazilian and foreign books, referring to the incidence and prevalence of infection by H.

Metabolic basis for the self-referential genetic code.

An investigation of the biosynthesis pathways producing glycine and serine was necessary to clarify an apparent inconsistency between the self-referential model (SRM) for the formation of the genetic code and the model of coevolution of encodings and of amino acid biosynthesis routes. According to the SRM proposal, glycine was the first amino acid encoded, followed by serine. The coevolution model does not state precisely which the first encodings were, only presenting a list of about ten early assignments including the derivation of glycine from serine-this being derived from the glycolysis intermediate glycerate, which reverses the order proposed by the self-referential model.

A self-referential model for the formation of the genetic code.

A model for the formation of the genetic code is presented where protein synthesis is directed initially by tRNA dimers. Proteins that are resistant to degradation and efficient RNA-binders protect the RNAs. Replication becomes elongational producing poly-tRNAs from which the mRNAs and ribosomes are derived.

Aminoacyl-tRNA synthetase classes and groups in prokaryotes.

Knowledge on the evolution of aminoacyl-tRNA synthetases is crucial to studies on the origins of life. The relationships between the different aminoacyl-tRNA synthetase specificities in prokaryotic organisms are studied in this work. We reconstructed the ancestor sequences and the phylogenetic relationships utilizing the Maximum Likelihood method.

Structure of the genetic code suggested by the hydropathy correlation between anticodons and amino acid residues.

The correlation between hydropathies of anticodons and amino acids, detected by other authors utilizing scales of amino acid molecules in solution, was improved with the utilization of scales of amino acid residues in proteins. Three partitions were discerned in the correlation plot with the principal dinucleotides of anticodons (pDiN, excluding the wobble position). (a) The set of outliers of the correlation: Gly-CC, Pro-GG, Ser-GA and Ser-CU.

Possible hepatotoxicity of chronic marijuana usage.

Context: Hepatotoxicity is a potential complication from the usage of various illicit drugs, possibly consequent to their liver metabolism, but information on this is scarce in the medical literature.

Objective: To study the occurrence of clinical and laboratory hepatic alterations in chronic marijuana users, from the use of marijuana on its own or in association with other legal or illicit drugs.

Type Of Study: transversal study

Setting: Hospital Espírita de Marília, Marília, São Paulo, Brazil

Participants: The study was made among 123 patients interned in the Hospital Espírita de Marília from October 1996 to December 1998, divided into 3 groups: 26 (21%) using only marijuana, 83 (67.

Female alcoholics: electrocardiographic changes and associated metabolic and electrolytic disorders.

Objective: To identify the electrocardiographic changes and their associations with metabolic and electrolytic changes in female alcoholics.

Methods: The study comprised 44 female alcoholics with no apparent physical disorder. They underwent the following examinations: conventional electrocardiography; serologic tests for syphilis, Chagas' disease, and hepatitis B and C viruses; urinary pregnancy testing; hematimetric analysis; biochemical measurements of albumin, fibrinogen, fasting and postprandial glycemias, lipids, hepatic enzymes, and markers for tissue necrosis and inflammation.

Histopathologic and biochemical liver test abnormalities in chronic asymptomatic or oligosymptomatic alcoholics: a review.

Purpose: To review the medical literature regarding the histopathologic and biochemical liver test abnormalities in chronic asymptomatic or oligosymptomatic alcoholics.

Methods: Review of articles in the MEDLINE and LILACS databases regarding serum levels and prevalence of alterations in aspartate-aminotransferase, alanine-aminotransferase, alkaline phosphatase, and total bilirubin, in relation to liver histopathology, with or without discrimination of types of histopathologic alteration.

Results: Global mean prevalence rates of aspartate-aminotransferase and alanine-aminotransferase alterations were 86.