Carlos Chagas Filho Research Articles

Biblioteca Virtual Carlos Chagas Filho: um espaço para divulgação da ciência brasileira contemporânea

Relata o processo de elaboração da biblioteca virtual dedicada à vida e obra de Carlos Chagas Filho. A pesquisa foi realizada no arquivo do próprio cientista e no de algumas instituições científicas e culturais em que ele atuou como membro e/ou dirigente. Os resultados obtidos até o momento demonstram que as informações e os documentos coletados contribuem para o conhecimento da prática científica no Brasil ao longo do século XX, bem como revelam suas interações com os movimentos das ciências biomédicas no exterior.

Occurrence of Gastroliths in Baurusuchus (Baurusuchidae, Mesoeucrocodylia) from Adamantina Formation, Bauru Basin

AbstractThe fossil record of Baurusuchidae Mesoeucrocodylia in the General Salgado county and its surroundings is one of the best regarding preservation, completeness and articulation of skull and skeleton remains, including specimens that shown even the most delicate bone structures and cartilaginous tissues. One of them, UFRJ DG 288-R, has preserved its skull and about 80% of its skeleton. During the removal of the rock matrix, on what should be the specimen’s abdominal region, together with fragments of gastralia were observed some small well-polished weathered angulous to subrounded clasts, presumed to be gastroliths. These xenoliths occur in a restrict cluster, where at least four peeble-sized stones are visible in the surface of the specimen. The texture and fabrics of these rock fragments differs from the surrounding matrix, presenting darker purplish tones. In thin section, one of the fragments revealed isotropic texture, with opaque minerals in abundance, of euhedric to subhedric habits. The mineralogical composition presents mainly clay minerals as weathering products; biotite and chlorite are common, being the last the result of hidratation of the first. Although highly altered, the low quartz content, small-sized and well-formed crystals suggests maphic composition in volcanic context, possibly representing a basalt fragment. In extant Crocodyliformes, the occurrence of gastroliths is commonly associated with food processing in the stomach, diving ballast, hunger stress and/or supplementary mineral ingestion. As baurusuchids are characterized as medium to large size fully terrestrial predator/scavengers, based on skeletal data, the ballast function of gasthroliths is excluded in this case. As mentioned above, extant crocodyliforms such as Caiman and Crocodylus ingest stones when under stressful conditions of lack of food, water or when in high population density. Osteoderms are one of the primary sources for calcium and a reservoir for the homeostasis. The hunger stress can be observed in the osteoderms histological cuts as an abnormal concentration of osteoclasts at its inner region overwhelming the presence of osteoblasts and consuming the osteocytes. The preservation of osteoderms associated with gasthroliths may reveal if the stone ingestion in baurusuchids is a normal or driven by hunger behavior. The paleoenvironmental conditions dominating the Adamantina Formation during the Late Cretaceous are considered mainly arid, marked with strong seasonality, alternating long droughts and short rainy periods, associated with flashflood events. The stressful condition created during the dry season would cause famine and mass mortality, thus forcing animals to endure or escape. The baurusuchids underwent the dry seasons through behavorial responses of self burial and probably stone ingestion, although natural bahavior cannot be eliminated as a cause. Financial support provided by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, grant no 305780/2006–9), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) and Instituto Virtual de Paleontologia/ Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (IVP/FAPERJ, grant no E–26/152.541/2006).

A opção de Carlos Chagas Filho pela física biológica: razões e motivações

Analisa as razões e motivações que teriam levado Carlos Chagas Filho a se afastar da linha tradicional de pesquisa de Carlos Chagas pai e de seu irmão Evandro Chagas, ambos muito bem sucedidos nos seus trabalhos em patologia tropical. Embora tenha inicialmente se dedicado à anatomia patológica, Carlos Chagas Filho subitamente decidiu enveredar pelo estudo da físico-química dos processos vitais. As fontes disponíveis demonstram a ocorrência de múltiplos imprevistos, desde os mais precoces períodos da formação de Chagas Filho. Trabalho de comparável grandeza poderia quiçá ser alcançado em outra área, e sua escolha recaiu, com acerto incomum, sobre a introdução da pesquisa científica na universidade.

Contrasting interactions mediate dissolved organic matter decomposition in tropical aquatic ecosystems

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 49:25-34 (2007) - DOI: https://doi.org/10.3354/ame01131 Contrasting interactions mediate dissolved organic matter decomposition in tropical aquatic ecosystems André Megali Amado1,2,3,*, James Bryan Cotner2, Albert Luiz Suhett1,3, Francisco de Assis Esteves1,4, Reinaldo Luiz Bozelli1, Vinicius Fortes Farjalla1,4 1Universidade Federal do Rio de Janeiro (UFRJ), Inst. de Biologia, Depto. de Ecologia, Laboratório de Limnologia, PO Box 68020, Prédio CCS, Av. Carlos Chagas Filho 373, Ilha do Fundão, Rio de Janeiro 21941-902, Brazil 2University of Minnesota (UMN), Department of Ecology Evolution and Behavior, 100 Ecology Building, 1987 Upper Buford Circle, St. Paul, Minnesota 55108, USA 3Universidade Federal do Rio de Janeiro (UFRJ), Programa de Pós-Graduação em Ecologia (PPGE) Prédio CCS, Av. Carlos Chagas Filho 373, Ilha do Fundão, Rio de Janeiro 21941-902, Brazil 4Núcleo de Pesquisas Ecológicas de Macaé (NUPEM/UFRJ), PO Box 119331, Rua Rotary Club, s/n, São José do Barreto, Macaé, Rio de Janeiro 27901-000, Brazil *Email: amado@biologia.ufrj.br ABSTRACT: The interaction between photochemical and microbial degradation processes can have important effects on dissolved organic matter (DOM) decomposition in aquatic systems. Photochemical processes can stimulate or inhibit biological DOM degradation while biological processes often stimulate photochemical degradation. The aim of the present study was to evaluate whether these 2 degradation processes compete for the same organic substrates or use complementary components in 2 tropical systems with contrasting DOM sources (one dominated by humic, mostly terrigenous DOM and the other dominated by autochthonous phytoplankton production). We performed sequential exposures of DOM from both systems to photochemical or biological degradation. We then measured bacterial growth and respiration and photochemical oxygen consumption in addition to changes in DOM optical properties. In the humic lagoon, photochemical degradation stimulated bacterial degradation up to 500% with little complementary photochemical stimulation by bacterial degradation (an increase of only 13%). In the eutrophic lagoon, we found that photochemical degradation inhibited bacterial degradation 17%, suggesting competition with microbial substrates, while bacterial degradation had no effect on photochemical degradation. The net effect of these eutrophic lagoon interactions was a ca. 2% reduction in dissolved organic carbon degradation. Thus, we conclude that there was net complementary behavior between photochemical and bacterial processes in the humic lagoon in DOM degradation, while we observed little net competitive behavior in the eutrophic lagoon. KEY WORDS: Dissolved organic matter · Photochemical degradation · Bacterial degradation · Dissolved organic carbon · Decomposition · Tropics Full text in pdf format PreviousNextCite this article as: Megali Amado A, Cotner JB, Suhett AL, Assis Esteves Fd, Bozelli RL, Farjalla VF (2007) Contrasting interactions mediate dissolved organic matter decomposition in tropical aquatic ecosystems. Aquat Microb Ecol 49:25-34. https://doi.org/10.3354/ame01131 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 49, No. 1. Online publication date: October 16, 2007 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2007 Inter-Research.

Ciência, política e paixão: o arquivo de Carlos Chagas Filho

Este texto tem por objetivo apresentar a relevância do arquivo de Carlos Chagas Filho como manancial de informações para os estudos da história da ciência no século XX. Pelo estudo dos documentos referentes às instituições em que atuou - tais como a Organização das Nações Unidas para a Educação, a Ciência e a Cultura e a Academia Pontifícia de Ciências do Vaticano - e naquelas de que foi criador - como o Instituto de Biofísica da Universidade Federal do Rio de Janeiro -, podemos resgatar facetas de sua trajetória dentro dos processos de formulação de políticas públicas de desenvolvimento e valorização da prática científica no Brasil e no exterior.

Carlos chagas filho, scientist and citizen

Carlos chagas filho, scientist and citizen

Biology and ultra-structure of Trypanosoma cruzi: a 90-year old challenge for scientists.

When Dr Carlos Chagas first observed underthe microscope the flagellate that he named Schizot-rypanum cruzi (today known as Trypanosomacruzi), in honor of his master and friend OswaldoCruz, he began to study the biology of this inter-esting microorganism (Chagas 1909). This uniquefact in medicine, a single person’s discovery andreport of the clinical picture of a new disease, witha new etiological agent, its life cycle, its vectorsand wild reservoirs, were later explained by him-self (Chagas 1922): a process that he was able tounderstand after the intense and basic studies onthe biology of this parasite, carried out at theOswaldo Cruz Institute. In Chagas’ own words“...quando no sangue periferico de uma criancafebril, observamos o flagelado patogenico, de suabiologia ja possuiamos nocao completa, adquiridaem demorados estudos anteriores” “...when wefound the pathogenic flagellate in the blood of achildren, we had already a complete notion of itsbiology, acquired under previous and detailed stud-ies” (Chagas 1922).Since then, the intriguing biology of this spe-cial parasite has been studied. Its morphology, de-picted under the optical microscopy of CarlosChagas and Garpar Vianna, was first investigatedunder an electron microscope by Dr Hertha Meyer(Meyer & Porter 1954). Dr Carlos Chagas Filho,Chagas’ son who founded in Rio de Janeiro thefamous Institute of Biophysics that later took hisname, achieved to establish Dr Hertha Meyer inthis Institute during the II World War. She starteda whole school of cell biology of T. cruzi (as wellas other tropical disease parasites), introducing invitro cell culture of muscle and nerve cells, andthe ultrastructure study of all the parasite develop-mental stages (reviewed in De Souza 1984). SinceDr Chagas’ time, some basic questions still chal-lenge the intelligence and curiosity of scientists allover the world. Why and how does the parasiteevolve among three different morphological andfunctional states of differentiation over its life cycle(ama-, epi- and trypomastigotes)? Does the T. cruzislender and stout forms found in blood stream ofdifferent host represent sexual dimorphism or any-thing else? How does T. cruzi enter so many dif-ferent cells? How does at least part of the parasitepopulation that infects a person or animal escapethe vigorous specific immune response elicited inthe host by the infection, leading to the finding ofviable forms during the decades-lasting chronic de-velopment of the disease?During the 90 years that followed since Chagas’classic report of a new disease, much informationwas obtained on the biology and ultrastructure ofits causative agent. Recent reviews from DrWanderley De Souza (1984, 1995) summarize theknowledge in this area. A large knowledge wasobtained on the understanding of its clonal com-position (Heckert et al. 1994, Tibayrenc 1995), aswell as in its population distribution and associ-ated biological and molecular markers (Zingaleset al. 1998). Another important field on parasitebiology investigation concerns its metabolic path-ways (reviewed in Cazzulo 1992), that engages thedesign of new drugs based on differences encoun-tered. Key organelles from which the parasite getsenergy such as acid calcisomes (DoCampo et al.1995) and reservosomes (Figueiredo et al. 1994)are under intense study. The same happens withsome pivotal enzymes for the parasite that are in-volved in energy production (such as glycosomalenzymes, purine and sterol byosynthetic pathways),detoxification (such as trypanothione reductase, or-nithine decarboxylase and S-adenosylmethioninedecarboxylase), or virulence (such as cysteine pro-teases) mechanisms. Second generation anti-try-panocidal drugs will certainly emerge from thisfield of research (Krauth-Siegel & Schoneck 1995,Cazzulo et al. 1997, Croft 1999, Urbina 1999) tosubstitute for the same two old and toxic drugs thatare currently available for clinical use since thesixties (benznidazole and nifurtimox).

Looking at science in Brazilian universities: The case of the instituto de Biofísica Carlos Chagas Filho

Performance indicators were built for the Instituto de Biofisica Carlos Chagas Filho, one of the most well-reputed Brazilian science centers. The Institute's performance presents a positive trend—articles number have doubled (1981–1995), and the articles impact grew from 4.20, in 1981, to 7.78, in 1990. This trend is probably being influenced by increasingly human resources involved in the Institute's scientific activities and by the continous growth of national and international collaboration. The follow up of indicators trends can be useful for the evaluation of long term policies directed to implement human resources programs and institutional collaborative work among scientific institutions.

P-C3-40 Esr spectroscopy of major intrinsic proteins of lens reconstituted in lipid vesicles: Bisch PM, 1 Prazeres G.MP, 1,2 Linhares MP, 3 1 Inst. Biofísica Carlos Chagas Filho UFRJ, Rio de Janeiro (BR), 2 Dept. Química UFMA, São Luis (BR), 3 Inst. Física UFRJ, Rio de Janeiro (BR)

P-C3-40 Esr spectroscopy of major intrinsic proteins of lens reconstituted in lipid vesicles: Bisch PM, 1 Prazeres G.MP, 1,2 Linhares MP, 3 1 Inst. Biofísica Carlos Chagas Filho UFRJ, Rio de Janeiro (BR), 2 Dept. Química UFMA, São Luis (BR), 3 Inst. Física UFRJ, Rio de Janeiro (BR)

P-F3-06 Nonlinear dynamics of lipid films under electric forces: C. Anteneodo, E. Ramos de Souza and P. M. Bisch Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro

P-F3-06 Nonlinear dynamics of lipid films under electric forces: C. Anteneodo, E. Ramos de Souza and P. M. Bisch Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro

Doença de Chagas

During 3 to 6 May 1964, a course on Chagas' disease was given in the Department of Clinical Therapeutics of the Faculty of Medicine of the Federal University of Minas Gerais, Belo Horizonte, Brazil. This book collects the presentations made in the course into 31 chapters. It has been a pleasure to read it and to review it, because I know (or knew; two are dead) most of the 35 collaborators, and many of them are good friends. Moreover, the book answers in part a question that has puzzled me: why was Brazil so slow to make a national effort toward the control of Chagas' disease, possibly the most important parasitic disease in the country? The answer is found in the initial chapter, by Carlos Chagas Filho, the only surviving son of Carlos Chagas. This is a dispassionate, objective discussion of the history of Chagas' disease in Brazil, from its discovery, in 1909, to 1964.