Romeu C Guimaraes | Univerdade Federal de Minas Gerais (original) (raw)
Papers by Romeu C Guimaraes
Resumen La sustitución experimental de genomas significa la creación de especies nuevas o la repr... more Resumen La sustitución experimental de genomas significa la creación de especies nuevas o la reprogramación genética de seres vivos, pero no la creación de vida. El proceso de integración del nuevo genoma al sistema metabólico receptor implica la sustitución gradual de las macromoléculas y no implica la existencia de la entidad especial llamada de información con respecto a la organización sistémica. El cambio de identidad genética de los organismos puede ser integral y completo.
PubMed, 1986
The uptake of adenine, guanine and hypoxanthine by Trypanosoma cruzi culture epimastigotes was st... more The uptake of adenine, guanine and hypoxanthine by Trypanosoma cruzi culture epimastigotes was studied over short time periods at 22 degrees C. The uptake process is concentrative, driven by the purine phosphoribosyltransferases and saturable at about 10 microM hypoxanthine and 1 microM adenine or guanine. Each purine base is apparently taken up by a separate route and the oxypurines are regulated in parallel. Adenine inhibits oxypurine uptake. When the material was incubated with guanine or hypoxanthine for more than 2 min, a decrease in the nucleotide/free base ratio was observed, indicating inhibition of the guanine and hypoxanthine phosphoribosyltransferases. The uptake rates during the ascending phase of uptake and of culture growth rates were of the order of 50 for hypoxanthine and 20 for guanine, relative to that of adenine. These rates were within the physiological range for cell growth in these cultures. During the phase of descending growth and decreased purine uptake activity rates, uptake was depressed to 20% of the rates required for the growth observed in the cultures. It is proposed that the decline in growth rate leads to an increase of the nucleotide pools in the cells which inhibit uptake. This depression may be a cause of the mitotic blockade which occurs during the stationary phase.
Endocytobiosis and Cell Research, Dec 1, 1992
Ciencia e Cultura, 1980
ABSTRACT
Journal of Biomolecular Structure & Dynamics, Nov 1, 2013
The conserved protein sequence motifs present in all prokaryotic proteomes, "omnipresent... more The conserved protein sequence motifs present in all prokaryotic proteomes, "omnipresent motifs," presumably, correspond to the earliest proteins of the Last Universal Cellular Ancestor, from which all the proteomes have descended. Fifteen proteomes, each representing one of the total 15 diverse phyla of 131 Eubacteria and Archea, from which the omnipresent elements have been originally derived, are exhaustively screened. All those proteins which harbor the omnipresent motifs are identified. Six "omnipresent" protein types are revealed which are located in all 15 proteomes: ABC cassettes, FtsH proteases, translation initiation factors, translation elongation factors, isoleucyl-tRNA synthases, and RNA polymerases β'. In addition to the omnipresent motifs, these proteins also contain other highly conserved motifs, standing for additional modules of the proteins. Remarkably, the identified tentative earliest proteins are responsible for only three basic functions: supply of monomers (ABC transporters and proteases), protein synthesis (initiation and elongation factors, aminoacyl-tRNA synthases), and RNA synthesis (polymerases). No enzymes involved in metabolic activities are present in the list of the earliest proteins derived by this approach. Some of the omnipresent sequence motifs are found, indeed, in the metabolic enzymes (e.g. NTP binding motifs), but these enzymes do not make a sequence matching collection of 15 sequences, i.e. they are not omnipresent. Future analysis of less conserved sequence motifs may reveal at what degree of conservation (stage of evolution) the metabolic enzymes could have entered the scene.
UNIV ESTADUAL PAULISTA JULIO DE MESQUITA FILHO,INST BASICO BIOL MED & AGR,DEPT GENET,BOTUCATU... more UNIV ESTADUAL PAULISTA JULIO DE MESQUITA FILHO,INST BASICO BIOL MED & AGR,DEPT GENET,BOTUCATU,BRAZIL
Horizonte: revista de Estudos de Teologia e Ciências da Religiao, 2010
Biodiversidade e Religião Biodiversity and religion Resumo Neste trabalho, explora-se o conceito ... more Biodiversidade e Religião Biodiversity and religion Resumo Neste trabalho, explora-se o conceito de que a diversidade propicia robustez nos sistemas processadores de informação, o que seria aplicável às areas neurais e so fenômeno religioso. Discutem sob a proposta de que demarcação adequada pode auxiliar na redução de conflitos. Nesse mesmo sentido pode contribuir a elaboração sobre as tensõ determinismos-e liberdades, que decorreriam do uso dos conceitos de crenças fortes e fracas, ou seja, entre crenças e hipóteses que parecem promissoras, merecedoras de créditos de confiança. Indica-se a possibilidade diversas, apesar das tendências globalizadoras que podem incidir sobre os aspectos mais materiais.
European Journal of Cell Biology, 1980
Brazilian journal of medical and biological research = Revista brasileira de pesquisas médicas e biológicas / Sociedade Brasileira de Biofísica ... [et al.], 1987
1. The pattern of purine base uptake in culture epimastigotes of Trypanosoma cruzi can be predict... more 1. The pattern of purine base uptake in culture epimastigotes of Trypanosoma cruzi can be predicted from cell growth rate and cell concentration, with the late log phase showing the greatest variability. 2. Uptake rates are unexpectedly low in the reproductive tissue amastigotes and high in the non-reproductive blood trypomastigotes. It is suggested that blood trypomastigotes metabolize and accumulate reserves of purine metabolites, whereas amastigotes depend on degradation of host cell RNA and nucleotides as purine sources. 3. All parasite forms salvage hypoxanthine and guanine in preference to adenine. Nifurtimox, dipyridamole and cytochalasin have no effect on uptake, whereas amphotericin B, allopurinol, xanthine and urate inhibit it. The alterations caused by urate are complex, apparently involving inhibition of the monooxypurine phosphoribosyltransferase and induction of permeation of purines into the cells.
Revista do Instituto de Medicina Tropical de São Paulo
AMB : revista da Associação Médica Brasileira, 1971
Memórias do Instituto Oswaldo Cruz, 1989
Uricemia was studied in a sample of 192 individuals from a highly endemic site for…
Journal of Biomolecular Structure and Dynamics, 2013
The conserved protein sequence motifs present in all prokaryotic proteomes, "omnipresent... more The conserved protein sequence motifs present in all prokaryotic proteomes, "omnipresent motifs," presumably, correspond to the earliest proteins of the Last Universal Cellular Ancestor, from which all the proteomes have descended. Fifteen proteomes, each representing one of the total 15 diverse phyla of 131 Eubacteria and Archea, from which the omnipresent elements have been originally derived, are exhaustively screened. All those proteins which harbor the omnipresent motifs are identified. Six "omnipresent" protein types are revealed which are located in all 15 proteomes: ABC cassettes, FtsH proteases, translation initiation factors, translation elongation factors, isoleucyl-tRNA synthases, and RNA polymerases β'. In addition to the omnipresent motifs, these proteins also contain other highly conserved motifs, standing for additional modules of the proteins. Remarkably, the identified tentative earliest proteins are responsible for only three basic functions: supply of monomers (ABC transporters and proteases), protein synthesis (initiation and elongation factors, aminoacyl-tRNA synthases), and RNA synthesis (polymerases). No enzymes involved in metabolic activities are present in the list of the earliest proteins derived by this approach. Some of the omnipresent sequence motifs are found, indeed, in the metabolic enzymes (e.g. NTP binding motifs), but these enzymes do not make a sequence matching collection of 15 sequences, i.e. they are not omnipresent. Future analysis of less conserved sequence motifs may reveal at what degree of conservation (stage of evolution) the metabolic enzymes could have entered the scene.
cibersaude.com.br
Moreira Jr Editora, RBM Revista Brasileira de Medicina e Pediatria Moderna, revistas médicas impr... more Moreira Jr Editora, RBM Revista Brasileira de Medicina e Pediatria Moderna, revistas médicas impressas e indexadas, notícias sobre saúde, agenda, cursos, congressos e eventos em medicina.
Acta Scientific Gastrointestinal Disorders, Feb 17, 2020
Some aspects and characteristics of alcoholism and of the alcoholics are universal while other ma... more Some aspects and characteristics of alcoholism and of the alcoholics are universal while other may differ between groups in consequence of the interaction between causal factors of each of the aspects under the influence of alcohol abuse. Statistical surveys have shown an increase in the production of alcoholic beverages of all kinds, and also provide evidence for the per capita alcohol consumption [1]. Such increment in the abusive ingestion of alcohol as severe individual, social and economic consequences, which motivates a growing number of investigations. The World Health Organization (WHO) classifies as aged, in developing countries, individuals higher than 60 years of age. The fraction of aged in the Brazilian population has grown from 4.8% in 1991 to 5.8% in 2000 and 7.4% in 2010 [2]. It is known that there are differences in the patterns of alcoholism according to the age segments, especially between the aged and non-aged groups [3]. According to the WHO, the average Brazilian consumption is around 8.7 liters of pure alcohol per person per year, while the world the average is 6.2 liters [4].
Resumen La sustitución experimental de genomas significa la creación de especies nuevas o la repr... more Resumen La sustitución experimental de genomas significa la creación de especies nuevas o la reprogramación genética de seres vivos, pero no la creación de vida. El proceso de integración del nuevo genoma al sistema metabólico receptor implica la sustitución gradual de las macromoléculas y no implica la existencia de la entidad especial llamada de información con respecto a la organización sistémica. El cambio de identidad genética de los organismos puede ser integral y completo.
PubMed, 1986
The uptake of adenine, guanine and hypoxanthine by Trypanosoma cruzi culture epimastigotes was st... more The uptake of adenine, guanine and hypoxanthine by Trypanosoma cruzi culture epimastigotes was studied over short time periods at 22 degrees C. The uptake process is concentrative, driven by the purine phosphoribosyltransferases and saturable at about 10 microM hypoxanthine and 1 microM adenine or guanine. Each purine base is apparently taken up by a separate route and the oxypurines are regulated in parallel. Adenine inhibits oxypurine uptake. When the material was incubated with guanine or hypoxanthine for more than 2 min, a decrease in the nucleotide/free base ratio was observed, indicating inhibition of the guanine and hypoxanthine phosphoribosyltransferases. The uptake rates during the ascending phase of uptake and of culture growth rates were of the order of 50 for hypoxanthine and 20 for guanine, relative to that of adenine. These rates were within the physiological range for cell growth in these cultures. During the phase of descending growth and decreased purine uptake activity rates, uptake was depressed to 20% of the rates required for the growth observed in the cultures. It is proposed that the decline in growth rate leads to an increase of the nucleotide pools in the cells which inhibit uptake. This depression may be a cause of the mitotic blockade which occurs during the stationary phase.
Endocytobiosis and Cell Research, Dec 1, 1992
Ciencia e Cultura, 1980
ABSTRACT
Journal of Biomolecular Structure & Dynamics, Nov 1, 2013
The conserved protein sequence motifs present in all prokaryotic proteomes, "omnipresent... more The conserved protein sequence motifs present in all prokaryotic proteomes, "omnipresent motifs," presumably, correspond to the earliest proteins of the Last Universal Cellular Ancestor, from which all the proteomes have descended. Fifteen proteomes, each representing one of the total 15 diverse phyla of 131 Eubacteria and Archea, from which the omnipresent elements have been originally derived, are exhaustively screened. All those proteins which harbor the omnipresent motifs are identified. Six "omnipresent" protein types are revealed which are located in all 15 proteomes: ABC cassettes, FtsH proteases, translation initiation factors, translation elongation factors, isoleucyl-tRNA synthases, and RNA polymerases β'. In addition to the omnipresent motifs, these proteins also contain other highly conserved motifs, standing for additional modules of the proteins. Remarkably, the identified tentative earliest proteins are responsible for only three basic functions: supply of monomers (ABC transporters and proteases), protein synthesis (initiation and elongation factors, aminoacyl-tRNA synthases), and RNA synthesis (polymerases). No enzymes involved in metabolic activities are present in the list of the earliest proteins derived by this approach. Some of the omnipresent sequence motifs are found, indeed, in the metabolic enzymes (e.g. NTP binding motifs), but these enzymes do not make a sequence matching collection of 15 sequences, i.e. they are not omnipresent. Future analysis of less conserved sequence motifs may reveal at what degree of conservation (stage of evolution) the metabolic enzymes could have entered the scene.
UNIV ESTADUAL PAULISTA JULIO DE MESQUITA FILHO,INST BASICO BIOL MED & AGR,DEPT GENET,BOTUCATU... more UNIV ESTADUAL PAULISTA JULIO DE MESQUITA FILHO,INST BASICO BIOL MED & AGR,DEPT GENET,BOTUCATU,BRAZIL
Horizonte: revista de Estudos de Teologia e Ciências da Religiao, 2010
Biodiversidade e Religião Biodiversity and religion Resumo Neste trabalho, explora-se o conceito ... more Biodiversidade e Religião Biodiversity and religion Resumo Neste trabalho, explora-se o conceito de que a diversidade propicia robustez nos sistemas processadores de informação, o que seria aplicável às areas neurais e so fenômeno religioso. Discutem sob a proposta de que demarcação adequada pode auxiliar na redução de conflitos. Nesse mesmo sentido pode contribuir a elaboração sobre as tensõ determinismos-e liberdades, que decorreriam do uso dos conceitos de crenças fortes e fracas, ou seja, entre crenças e hipóteses que parecem promissoras, merecedoras de créditos de confiança. Indica-se a possibilidade diversas, apesar das tendências globalizadoras que podem incidir sobre os aspectos mais materiais.
European Journal of Cell Biology, 1980
Brazilian journal of medical and biological research = Revista brasileira de pesquisas médicas e biológicas / Sociedade Brasileira de Biofísica ... [et al.], 1987
1. The pattern of purine base uptake in culture epimastigotes of Trypanosoma cruzi can be predict... more 1. The pattern of purine base uptake in culture epimastigotes of Trypanosoma cruzi can be predicted from cell growth rate and cell concentration, with the late log phase showing the greatest variability. 2. Uptake rates are unexpectedly low in the reproductive tissue amastigotes and high in the non-reproductive blood trypomastigotes. It is suggested that blood trypomastigotes metabolize and accumulate reserves of purine metabolites, whereas amastigotes depend on degradation of host cell RNA and nucleotides as purine sources. 3. All parasite forms salvage hypoxanthine and guanine in preference to adenine. Nifurtimox, dipyridamole and cytochalasin have no effect on uptake, whereas amphotericin B, allopurinol, xanthine and urate inhibit it. The alterations caused by urate are complex, apparently involving inhibition of the monooxypurine phosphoribosyltransferase and induction of permeation of purines into the cells.
Revista do Instituto de Medicina Tropical de São Paulo
AMB : revista da Associação Médica Brasileira, 1971
Memórias do Instituto Oswaldo Cruz, 1989
Uricemia was studied in a sample of 192 individuals from a highly endemic site for…
Journal of Biomolecular Structure and Dynamics, 2013
The conserved protein sequence motifs present in all prokaryotic proteomes, "omnipresent... more The conserved protein sequence motifs present in all prokaryotic proteomes, "omnipresent motifs," presumably, correspond to the earliest proteins of the Last Universal Cellular Ancestor, from which all the proteomes have descended. Fifteen proteomes, each representing one of the total 15 diverse phyla of 131 Eubacteria and Archea, from which the omnipresent elements have been originally derived, are exhaustively screened. All those proteins which harbor the omnipresent motifs are identified. Six "omnipresent" protein types are revealed which are located in all 15 proteomes: ABC cassettes, FtsH proteases, translation initiation factors, translation elongation factors, isoleucyl-tRNA synthases, and RNA polymerases β'. In addition to the omnipresent motifs, these proteins also contain other highly conserved motifs, standing for additional modules of the proteins. Remarkably, the identified tentative earliest proteins are responsible for only three basic functions: supply of monomers (ABC transporters and proteases), protein synthesis (initiation and elongation factors, aminoacyl-tRNA synthases), and RNA synthesis (polymerases). No enzymes involved in metabolic activities are present in the list of the earliest proteins derived by this approach. Some of the omnipresent sequence motifs are found, indeed, in the metabolic enzymes (e.g. NTP binding motifs), but these enzymes do not make a sequence matching collection of 15 sequences, i.e. they are not omnipresent. Future analysis of less conserved sequence motifs may reveal at what degree of conservation (stage of evolution) the metabolic enzymes could have entered the scene.
cibersaude.com.br
Moreira Jr Editora, RBM Revista Brasileira de Medicina e Pediatria Moderna, revistas médicas impr... more Moreira Jr Editora, RBM Revista Brasileira de Medicina e Pediatria Moderna, revistas médicas impressas e indexadas, notícias sobre saúde, agenda, cursos, congressos e eventos em medicina.
Acta Scientific Gastrointestinal Disorders, Feb 17, 2020
Some aspects and characteristics of alcoholism and of the alcoholics are universal while other ma... more Some aspects and characteristics of alcoholism and of the alcoholics are universal while other may differ between groups in consequence of the interaction between causal factors of each of the aspects under the influence of alcohol abuse. Statistical surveys have shown an increase in the production of alcoholic beverages of all kinds, and also provide evidence for the per capita alcohol consumption [1]. Such increment in the abusive ingestion of alcohol as severe individual, social and economic consequences, which motivates a growing number of investigations. The World Health Organization (WHO) classifies as aged, in developing countries, individuals higher than 60 years of age. The fraction of aged in the Brazilian population has grown from 4.8% in 1991 to 5.8% in 2000 and 7.4% in 2010 [2]. It is known that there are differences in the patterns of alcoholism according to the age segments, especially between the aged and non-aged groups [3]. According to the WHO, the average Brazilian consumption is around 8.7 liters of pure alcohol per person per year, while the world the average is 6.2 liters [4].
(1) The logic of the living is the metabolic flow that is embedded in the universal and geochemic... more (1) The logic of the living is the metabolic flow that is embedded in the universal and geochemical flows. (2) At the origins of the genetic code, there is (proto)tRNA Dimer-Directed Polymerization [constitution of (proto)tRNA is not known]. (2a) The flow is slow because syntheses are bi-directional. Dimers are proto-ribosomes: structures that hold tRNAs together and propitiate the transferase reaction. (2b) (proto)tRNAs in the dimers are complementary, equivalent, superposed, coherent. ● An anticodon is at the same time codon for the other ● Products grow at both (proto)tRNAs. (3) Mechanism: Peptide products that are capable of (proto)tRNA binding and stabilization, without disrupting their activities, establish a self-referential self-stimulatory nucleoprotein production system, at the birth of cells. (4) Decoherence: Separation of the members of dimers was provoked by, among other possible interferences (e. g., proteins), intromission of the mRNA strings, which may have originated from enchaining of segments of the (proto)tRNAs
(5) At translation (better, transliteration), Ribosome-Directed Polymerization is directional and the flow is fast. Genetic strings (mRNA) are scanned by laterally associated couples (instead of dimers of tRNAs) that enchain the carried amino acids into proteins.