RUNX2 belongs to the RUNT domain family of transcription factors of which three have been identified in humans (RUNX1, RUNX2 and RUNX3). RUNX proteins are vital for metazoan development and participate in the regulation of cellular differentiation and cell cycle progression (Coffman, 2003). RUNX2 is required for proper bone formation by driving the differentiation of osteoblasts from mesenchymal progenitors during development (Ducy et al, 1997; Komori et al, 1997; Otto et al, 1997). RUNX2 is also vital for chondrocyte maturation by promoting the differentiation of chondrocytes to the hypertrophic phenotype (Enomoto et al, 2000). The consequences of completely disrupting the RUNX2 locus in mice provided compelling and conclusive evidence for the biological importance of RUNX2 where knockout mice died shortly after birth with a complete lack of bone formation (Komori et al, 1997; Otto et al, 1997). A further indication of the requisite role of RUNX2 in skeletal development was the discovery that RUNX2 haploinsufficiency in humans and mice caused the skeletal syndrome Cleidocranial Dysplasia (CCD) (Mundlos et al, 1997; Lee et al, 1997). A unique feature of RUNX2 is the consecutive polyglutamine and polyalanine tracts (Q/A domain). Mutations causing CCD have been observed in the Q/A domain of RUNX2 (Mundlos et al, 1997). The Q/A domain is an essential part of RUNX2 and participates in transactivation function (Thirunavukkarasu et al, 1998). Previous genotyping studies conducted in our laboratory identified several rare RUNX2 Q/A variants in addition to a frequently occurring 18 base pair deletion of the polyalanine tract termed the 11Ala allele. Analysis of serum parameters in 78 Osteoarthritis patients revealed the 11Ala allele was associated with significantly decreased osteocalcin. Furthermore, analysis of 11Ala allele frequencies within a Geelong Osteoporosis Study (GOS) fracture cohort and an appropriate age matched control group revealed the 11Ala allele was significantly overrepresented in fracture cases indicating an association with increased fracture risk. To further investigate the 11Ala allele and rare Q/A variants, 747 DNA samples from the Southeast Queensland bone study were genotyped using PCR and PAGE. The experiment served two purposes: 1) to detect additional rare Q/A variants to enrich the population of already identified mutants and 2) have an independent assessment of the effect of the 11Ala allele on fracture to either support or refute our previous observation which indicated the 11Ala allele was associated with an increased risk of fracture in the GOS. From the 747 samples genotyped, 665 were WT, 76 were heterozygous for the 11Ala allele, 5 were homozygous for the 11Ala allele and 1 was heterozygous for a rare 21 bp deletion of the polyglutamine tract. Chi-square analysis of RUNX2 genotype distributions within fracture and non-fracture groups in the Southeast Queensland bone study revealed that individuals that carried at least one copy of the 11Ala allele were enriched in the fracture group (p = 0.16, OR = 1.712). The OR of 1.712 was of similar magnitude to the OR observed in the GOS case-control investigation (OR = 1.9) providing support for the original study. Monte-Carlo simulations were used to combine the results from the GOS and the Southeast Queensland bone study. The simulations were conducted with 10000 iterations and demonstrated that the maximum probability of obtaining both study results by chance was less than 5 times in two hundred (p < 0.025) suggesting that the 11Ala allele of RUNX2 was associated with an increased fracture risk. The second element of the research involved the analysis of rare RUNX2 Q/A variants identified from multiple epidemiological studies of bone. Q/A repeat variants were derived from four populations: the GOS, an Aberdeen cohort, CAIFOS and a Sydney twin study. Collectively, a total of 20 rare glutamine and one alanine variants were identified from 4361 subjects. All RUNX2 Q/A variants were heterozygous for a mutant allele and a wild type allele. Analysis of incident fracture during a five year follow up period in the CAIFOS revealed that Q-variants (n = 8) were significantly more likely to have fractured compared to non-carriers (p = 0.026, OR 4.932 95% CI 1.2 to 20.1). Bone density data as measured by quantitative ultrasound was available for CAIFOS. Analysis of BUA and SOS Z-scores revealed that Q-repeat variants had significantly lower BUA (p = 0.031, mean Z-score of -0.79) and a trend for lower SOS (p = 0.190, mean Z-score of -0.69). BMD data was available for all four populations. To normalize the data across the four studies, FN BMD data was converted into Z-scores and the effect of the Q/A variants on BMD was analysed using a one sample approach. The analysis revealed Q/A variants had significantly lower FN BMD (p = 0.0003) presenting with a 0.65 SD decrease. Quantitative transactivation analysis was conducted on RUNX2 proteins harbouring rare glutamine mutations and the 11Ala allele. RUNX2 proteins containing a glutamine deletion (16Q), a glutamine insertion (30Q) and the 11Ala allele were overexpressed in NIH3T3 and HEK293 cells and their ability to transactivate a known target promoter was assessed. The 16Q and 30Q had significantly decreased reporter activity compared to WT in NIH3T3 cells (p = 0.002 and 0.016, for 16Q and 30Q, respectively). In contrast 11Ala RUNX2 did not show significantly different promoter activation potential (p = 0.54). Similar results were obtained in HEK293 cells where both the 16Q and 30Q RUNX2 displayed decreased reporter activity (p=0.007 and 0.066 for 16Q and 30Q respectively) whereas the 11Ala allele had no material effect on RUNX2 function (p = 0.20). The RUNX2 gene target reporter assay provided evidence to suggest that variation within the glutamine tract of RUNX2 was capable of altering the ability of RUNX2 to activate a known target promoter. In contrast, the 11Ala allele showed no variation in RUNX2 activity. The third feature of the research served the purpose of identifying potential RUNX2 gene targets with particular emphasis on discovering genes cooperatively regulated by RUNX2 and the powerful bone promoting agent BMP2. The experiment was conducted by creating stably transfected NIH3T3 cells lines overexpressing RUNX2 or BMP2 or both RUNX2 and BMP2. Microarray analysis revealed very few genes were differentially regulated between standard NIH3T3 cells and cells overexpressing RUNX2. The results were confirmed via RT-PCR analysis which demonstrated that the known RUNX2 gene targets Osteocalcin and Matrix Metalloproteinase-13 were modestly induced 2.5 fold (p = 0.00017) and 2.1 fold (p = 0.002) respectively in addition to identifying only two genes (IGF-II and SCYA11) that were differentially regulated greater than 10 fold. IGF-II and SYCA11 were significantly down-regulated 27.6 fold (p = 1.95 x 10-6) and 10.1 fold (p = 0.0002) respectively. The results provided support for the notion that RUNX2 on its own was not sufficient for optimal gene expression and required the presence of additional factors. To discover genes cooperatively regulated by RUNX2 and BMP2, microarray gene expression analysis was performed on standard NIH3T3 cells and NIH3T3 cells stably transfected with both RUNX2 and BMP2. Comparison of the gene expression profiles revealed the presence of a large number of differentially regulated genes. Four genes EHOX, CCL9, CSF2 and OSF-1 were chosen to be further characterized via RT-PCR. Sequential RT-PCR analysis on cDNA derived from control cells and cells stably transfected with either RUNX2, BMP2 or both RUNX2/BMP2 revealed that EHOX and CSF2 were cooperatively induced by RUNX2 and BMP2 whereas CCL9 and OSF-1 were suppressed by BMP2. The overexpression of both RUNX2 and BMP2 in NIH3T3 fibroblasts provided a powerful model upon which to discover potential RUNX2 gene targets and also identify genes synergistically regulated by BMP2 and RUNX2. The fourth element of the research investigated the role of RUNX2 in the ascorbic acid mediated induction of MMP-13 mRNA. The study was carried out using NIH3T3 cell lines stably transfected with BMP2, RUNX2 and both BMP2 and RUNX2. The cell lines were grown to confluence and subsequently cultured for a further 12 days in standard media or in media supplemented with AA. RT-PCR analysis was used to assess MMP-13 mRNA expression. The RT-PCR results demonstrated that AA was not sufficient for inducing MMP-13 mRNA in NIH3T3 cells. In contrast RUNX2 significantly induced MMP-13 levels 85 fold in the absence of AA (p = 0.0055) and upregulated MMP-13 mRNA levels 254 fold in the presence of AA (p = 0.0017). The results demonstrated that RUNX2 was essential for the AA mediated induction of MMP-13 mRNA in NIH3T3 cells. The effect of BMP2 on MMP-13 expression was also investigated. BMP2 induced MMP-13 mRNA transcripts a modest 3.8 fold in the presence of AA (p = 0.0027). When both RUNX2 and BMP2 were overexpressed in the presence of AA, MMP-13 mRNA levels were induced a massive 4026 fold (p = 8.7 x 10-4) compared to control cells. The investigation revealed that RUNX2 was an essential factor for the AA mediated induction of MMP-13 and that RUNX2 and BMP2 functionally cooperated to regulate MMP-13 mRNA levels.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2016-09-14T11:46:46Z No. of bitstreams: 1 2011 - Vivian Suane de Freitas Vieira.pdf: 2001045 bytes, checksum: 2cce4947186746927e3f6cc35826b411 (MD5) / Made available in DSpace on 2016-09-14T11:46:46Z (GMT). No. of bitstreams: 1 2011 - Vivian Suane de Freitas Vieira.pdf: 2001045 bytes, checksum: 2cce4947186746927e3f6cc35826b411 (MD5) Previous issue date: 2016-01-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / A list of metazoan species associated to Pimelodus Lac?p?de, 1803 genus has been prepared in this work. The total of 516 records in 10 host species of genus was compiled. Were included in the list of new geographic records monogeneans parasites of Pimelodus maculatus Lac?p?de, 1803 collected from Midwest, Southeast and South of Brazil. New morphological data of Cucullanus pinnai pinnai Travassos, Artigas & Pereira, 1928, parasite of P. maculatus collected in the Guandu river, in the State of Rio de Janeiro have been reported. This work noted that the position of the excretory pore and deirids of the specimens are at the level or posterior to the oesophagus- intestine junction in the most specimens and gubernaculums size is greater than in other previously studied of C. pinnai pinnai. Nematodes were studied using light and scanning electron microscopy (SEM) and differential interference contrast (DIC) and analyzes confirmed morphological details of the cephalic region and the caudal papillae that species. Comparative study of parasitic communities of P. maculatus was also performed. 50 specimens of the P. maculatus were collected from Guandu river, in the State of Rio de Janeiro and others 50 from Mogi-Gua?? river, State of S?o Paulo. In the samples from Guandu river were identified the following species: Ameloblastella paranaensis Fran?a, Isaac, Pavanelli & Takemoto, 2003 (P= 8%; MI= 1,0?0,0); A. satoi Monteiro, Kritsky, Brasil-Sato, 2010 (P= 8%; MI= 1,0?0,0); Demidospermus bidiverticulatum Suriano & Incorvaia, 1995 (P= 8%; MI= 1,0?0,0); D. paravalenciennesi Guti?rrez & Suriano, 1992 (P=90%; MI=14,77?5,04), D. uncusvalidus Guti?rrez & Suriano, 1992 (P=90%; MI=12,37?4,86), D. valenciennesi Guti?rrez & Suriano, 1992 (P=56%; MI=6,06?3,95) e Cucullanus pinnai pinnai Travassos, Artigas & Pereira, 1928 (P=64%; MI=3,28?4,87). In the rio Mogi-Gua?? the parasites identified were: Ameloblastella paranaensis (P= 8%; MI= 1,0?0,0), Ameloblastella satoi (P= 8%; MI= 1,0?0,0), Demidospermus paravalenciennesi (P=86%; MI=18,58?10,79), D. uncusvalidus (P=84%; MI=16,73?7,74), D. valenciennesi (P=52%; IM=6,84?4,55) e Cucullanus pinnai pinnai (P= 44%; MI= 3,88?4,87). The females of P. maculatus had higher weight and length of males in both samples. The sex and o length of the hosts did not influence the level of parasitism. Positive correlation was observed between weight of host and abundance of D. uncusvalidus only in the sample of the Guandu river. Aggregate distribution was observed in all the prevalent species of metazoan parasites of P. maculatus in the two localities. D. paravalenciennesi showed a higher frequency of dominance and relative dominance in the samples of Guandu river and D. uncusvalidus in the samples of Mogi-Gua?? river. The results of the qualitative similarity index Jaccard (CJ) and quantitative Sorensen (CS) within the collected samples were homogenea. The Jaccard index indicated heterogeneity while Sorensen index indicated homogeneity between samples. The results demonstrated that the relationship between parasites and their hosts are constant even in different river basins. / Uma lista de esp?cies de metazo?rios associados ao g?nero Pimelodus Lac?p?de, 1803 foi elaborada neste trabalho. O total de 516 registros em 10 esp?cies de hospedeiros do g?nero foi compilado. Foram inclu?dos na lista novos registros de geogr?ficos de parasitos monogen?ticos de Pimelodus maculatus Lac?p?de, 1803 coletados nas regi?es Centro-oeste, Sudeste e Sul do Brasil. Novos dados morfol?gicos de Cucullanus pinnai pinnai Travassos, Artigas & Pereira, 1928, parasito de P. maculatus coletado no rio Guandu, no Estado do Rio de Janeiro foram relatados. Foi observado que a posi??o do poro excretor e deir?deos nos esp?cimes estudados s?o posteriores ao final do es?fago na maioria dos esp?cimes e o tamanho do gubern?culo ? maior do que em outros de C. pinnai pinnai estudados anteriormente. Os nematoides foram estudados utilizando microscopia eletr?nica de varredura (MEV) e contraste interferencial de fase (DIC) e as an?lises confirmaram detalhes morfol?gicos da regi?o cef?lica e as papilas caudais dessa esp?cie. Estudo comparativo das comunidades parasit?rias de P. maculatus tamb?m foi realizado. Foram coletados 50 esp?cimes de P. maculatus no rio Guandu, no Estado do Rio de Janeiro e outros 50 exemplares no rio Mogi-Gua??, no Estado de S?o Paulo, foram examinados para o estudo de sua parasitofauna, no per?odo de maio ? dezembro de 2012. No rio Guandu foram coletadas as seguintes esp?cies: Ameloblastella paranaensis Fran?a, Isaac, Pavanelli & Takemoto, 2003 (P= 8%; IM= 1,0?0,0); A. satoi Monteiro, Kritsky, Brasil-Sato, 2010 (P= 8%; IM= 1,0?0,0); Demidospermus bidiverticulatum Suriano & Incorvaia, 1995 (P= 8%; IM= 1,0?0,0); D. paravalenciennesi Guti?rrez & Suriano, 1992 (P=90%; IM=14,77?5,04), D. uncusvalidus Guti?rrez & Suriano, 1992 (P=90%; IM=12,37?4,86), D. valenciennesi Guti?rrez & Suriano, 1992 (P=56%; IM=6,06?3,95) e Cucullanus pinnai pinnai Travassos, Artigas & Pereira, 1928 (P=64%; IM=3,28?4,87). No rio Mogi-Gua?? os parasitos identificados foram: Ameloblastella paranaensis (P= 8%; IM= 1,0?0,0), Ameloblastella satoi (P= 8%; IM= 1,0?0,0), Demidospermus paravalenciennesi (P=86%; IM=18,58?10,79), D. uncusvalidus (P=84%; IM=16,73?7,74), D. valenciennesi (P=52%; IM=6,84?4,55) e Cucullanus pinnai pinnai (P= 44; IM= 3,88?4,87). As f?meas de P. maculatus apresentaram peso e comprimento maiores que dos machos nas duas amostras. O sexo e o comprimento dos hospedeiros n?o influenciaram o n?vel de parasitismo. Correla??o positiva foi observada entre o peso e a abund?ncia de D. uncusvalidus somente na amostra do rio Guandu. Foi observada distribui??o agregada de todas as esp?cies mais prevalentes de metazo?rios parasitos de P. maculatus nas duas bacias de coleta. D. paravalenciennesi apresentou maior freq??ncia de domin?ncia e domin?ncia relativa no rio Guandu e D. uncusvalidus no rio Mogi-Gua??. Os resultados dos ?ndices de similaridade qualitativa de Jaccard (CJ) e quantitativa de Sorensen (CS) dentro das amostras coletadas demonstraram homogeneidade. O ?ndice Jaccard indicou heterogeneidade e o ?ndice de Sorensen indicou homogeneidade entre as amostras. Os resultados demonstram que o relacionamento entre parasitos e seus hospedeiros s?o constantes, mesmo em diferentes bacias hidrogr?ficas.

Orientador: Luciano Alves dos Anjos / Resumo: A região Neotropical é reconhecida pela alta diversidade de peixes dulcícolas, com aproximadamente 6.025 espécies. Deste total, 66% estão distribuídos nos rios brasileiros refletindo a grande diversidade dos ecossistemas aquáticos disponíveis. Os sistemas de planície de inundação são ecossistemas que contribuiu para essa megadiversidade devido à complexidade ambiental. A Reserva Particular do Patrimônio Natural (RPPN) Foz do rio Aguapeí é um desses ricos e complexos ecossistemas aquáticos. É influenciado por pulsos de inundação que alteram os ambientes, moldando a composição e a estrutura das comunidades dos parasitos de peixes desta localidade. Dentre os peixes da região, os Siluriformes Auchenipterus osteomystax e Parauchenipterus galeatus apresentam similaridades biológicas e ecológicas. Neste trabalho as suas faunas parasitárias foram inventariadas e utilizadas para testar os efeitos das estações seca e chuvosa sobre a composição e estrutura dessas comunidades. Uma nova espécie de monogenea foi encontrada e descrita. O presente estudo compara os efeitos dessas estações sobre os níveis de parasitismo desses hospedeiros. Estudos prévios corroboram a importância da dinâmica espacial e temporal do pulso de inundação nesses ecossistemas para a manutenção da diversidade. Por fim, as ações antrópicas impostas pelas usinas hidrelétricas da região podem afetar diretamente as condições biológicas e recrutamento dos peixes, influenciando a interação parasito-hospedeiro. / Abstract: The Neotropical region is recognized by high diversity of freshwater fish, with approximately 6,025 species. Of that total, 66% are distributed in the Brazilian rivers reflecting the high diversity of aquatic ecosystems available. The river-floodplains systems are ecosystems that contributed to this megadiversity due to environmental complexity. The Reserva de Particular Patrimônio Nacional (RPPN) from the Mouth of Aguapeí River is one of these rich and complexity aquatic ecosystems. It is influenced by floods that change the environments, shaping the composition and structure of fish parasites of this location. Among the fishes of this region, the Siluriformes Auchenipterus osteomystax and Parauchenipterus galeatus exhibit biological and ecological similarities. Its parasite fauna have been listed and used to test the dry and rainy season effects on the composition and structure of these communities. The present study compares the effects of these seasons on levels of parasitism of these hosts. The previous studies corroborate the relevance of spatial and temporal dynamics of the flood pulse in these ecosystems to maintenance of diversity. Finally, the anthropic actions imposed by regional hydroelectric power could direct affect the biological condition and fish recruitment, influencing the host-parasite interaction. / Mestre

O objetivo principal de nosso trabalho é descrever e analisar criticamente o núcleo da teoria da gastrea de Ernst Haeckel. Ele gira em torno de duas noções principais: forma gastrular e metazoário. A teoria da gastrea é um conjunto de formulações que visa estabelecer uma definição de metazoário a partir da noção de forma gastrular. O argumento central da teoria da gastrea articula essas duas noções para organizar a partir de estudos de embriologia comparativa uma visão geral da história evolutiva do reino animal. / The main goal of our work is to describe and critically analyze the core of the gastrea theory of Ernst Haeckel. It centers around two main notions: gastrula form and metazoan. The gastrea theory is a set of formulations designed to establish a definition of metazoan from the notion of gastrula form. The central argument of the gastrea theory articulates these two notions to organize from studies of comparative embryology an overview of evolutionary history of the animal kingdom.

Os modelos de evolução de vias metabólicas estão baseados em técnicas moleculares e bioinformática e nem sempre levam em consideração o contextos fisiológico e ecológico do organismo. Assim, tomando como plataforma o metabolismo de nitrogênio, procurou-se estabelecer uma hipótese evolutiva para o uso de &#945;-aminoácidos por metazoários como fonte de nitrogênio. O objetivo é traçar essa história evolutiva, contextualizando fisiológica e ecologicamente as alterações que ocorreram no perfil de utilização desses compostos. Para traçar essa história evolutiva, recorreu-se a dados disponíveis na literatura partindo-se dos elementos moleculares/metabólicos que compõem o ciclo do nitrogênio e em qual contexto geológico e evolutivo se deu tal história. Os dados obtidos, reorganizados e reestruturados nesse novo contexto, permitiram conclusões originais no presente trabalho, a saber: (1) a capacidade de fixação de nitrogênio atmosférico foi um fator de seleção natural positiva na transição da atmosfera redutora para oxidante; (2) os organismos fixadores de nitrogênio são bem mais disseminados do que o admitido classicamente; (3) o produto final da fixação biológica de nitrogênio in vivo são &#945;- aminoácidos, e foram um fator de pressão seletiva para os organismos incapazes de fixar nitrogênio; (4) os metazoários evoluíram posteriormente a esse cenário e seu aparato metabólico está mais adaptado para o aproveitamento líquido do nitrogênio obtido apenas na forma de &#945;-aminoácidos. / Metabolic pathway evolution models are molecular and computational based, and do not take account the physiological and ecological contexts in which organisms are inserted. Thus using the nitrogen metabolism as a platform, an evolutionary hypothesis on the &#945;-amino acids utilization by metazoans was proposed. The objective of the present work is to trace an evolutionary history of the nitrogen usage by metazoans taking account the profile changes on a physiological and ecological basis. In order to trace this evolutionary history, a scrutiny were performed in the specialized literature aiming at data about the molecular and metabolic elements which perform the nitrogen cycle and in which geologic and evolutive context has passed such history. The reorganization of obtained data in a new context allowed original conclusions in the present work as follows: (1) the capability of fixing the atmospheric nitrogen was a positive selection factor in the atmospheric condition transition from reductive to oxidant; (2) nitrogen fixing organisms are far most wide spread than classically admitted; (3) &#945;-amino acids are the biological nitrogen fixation end product in vivo, and are a selective factor for non-fixing organisms; (4) metazoans evolved afterwards in these scenario and their metabolic apparatus is adapted to the nitrogen net utilization obtained in the &#945;-amino acid form.

Os modelos de evolução de vias metabólicas estão baseados em técnicas moleculares e bioinformática e nem sempre levam em consideração o contextos fisiológico e ecológico do organismo. Assim, tomando como plataforma o metabolismo de nitrogênio, procurou-se estabelecer uma hipótese evolutiva para o uso de &#945;-aminoácidos por metazoários como fonte de nitrogênio. O objetivo é traçar essa história evolutiva, contextualizando fisiológica e ecologicamente as alterações que ocorreram no perfil de utilização desses compostos. Para traçar essa história evolutiva, recorreu-se a dados disponíveis na literatura partindo-se dos elementos moleculares/metabólicos que compõem o ciclo do nitrogênio e em qual contexto geológico e evolutivo se deu tal história. Os dados obtidos, reorganizados e reestruturados nesse novo contexto, permitiram conclusões originais no presente trabalho, a saber: (1) a capacidade de fixação de nitrogênio atmosférico foi um fator de seleção natural positiva na transição da atmosfera redutora para oxidante; (2) os organismos fixadores de nitrogênio são bem mais disseminados do que o admitido classicamente; (3) o produto final da fixação biológica de nitrogênio in vivo são &#945;- aminoácidos, e foram um fator de pressão seletiva para os organismos incapazes de fixar nitrogênio; (4) os metazoários evoluíram posteriormente a esse cenário e seu aparato metabólico está mais adaptado para o aproveitamento líquido do nitrogênio obtido apenas na forma de &#945;-aminoácidos. / Metabolic pathway evolution models are molecular and computational based, and do not take account the physiological and ecological contexts in which organisms are inserted. Thus using the nitrogen metabolism as a platform, an evolutionary hypothesis on the &#945;-amino acids utilization by metazoans was proposed. The objective of the present work is to trace an evolutionary history of the nitrogen usage by metazoans taking account the profile changes on a physiological and ecological basis. In order to trace this evolutionary history, a scrutiny were performed in the specialized literature aiming at data about the molecular and metabolic elements which perform the nitrogen cycle and in which geologic and evolutive context has passed such history. The reorganization of obtained data in a new context allowed original conclusions in the present work as follows: (1) the capability of fixing the atmospheric nitrogen was a positive selection factor in the atmospheric condition transition from reductive to oxidant; (2) nitrogen fixing organisms are far most wide spread than classically admitted; (3) &#945;-amino acids are the biological nitrogen fixation end product in vivo, and are a selective factor for non-fixing organisms; (4) metazoans evolved afterwards in these scenario and their metabolic apparatus is adapted to the nitrogen net utilization obtained in the &#945;-amino acid form.

O objetivo principal de nosso trabalho é descrever e analisar criticamente o núcleo da teoria da gastrea de Ernst Haeckel. Ele gira em torno de duas noções principais: forma gastrular e metazoário. A teoria da gastrea é um conjunto de formulações que visa estabelecer uma definição de metazoário a partir da noção de forma gastrular. O argumento central da teoria da gastrea articula essas duas noções para organizar a partir de estudos de embriologia comparativa uma visão geral da história evolutiva do reino animal. / The main goal of our work is to describe and critically analyze the core of the gastrea theory of Ernst Haeckel. It centers around two main notions: gastrula form and metazoan. The gastrea theory is a set of formulations designed to establish a definition of metazoan from the notion of gastrula form. The central argument of the gastrea theory articulates these two notions to organize from studies of comparative embryology an overview of evolutionary history of the animal kingdom.