Xylem Transcription Profiles Indicate Potential Metabolic Responses For Economically Relevant Characteristics Of Eucalyptus Species.

Eucalyptus is one of the most important sources of industrial cellulose. Three species of this botanical group are intensively used in breeding programs: E. globulus, E. grandis and E. urophylla. E. globulus is adapted to subtropical/temperate areas and is considered a source of high-quality cellulose; E. grandis grows rapidly and is adapted to tropical/subtropical climates; and E. urophylla, though less productive, is considered a source of genes related to robustness. Wood, or secondary xylem, results from cambium vascular differentiation and is mostly composed of cellulose, lignin and hemicelluloses. In this study, the xylem transcriptomes of the three Eucalyptus species were investigated in order to provide insights on the particularities presented by each of these species. Data analysis showed that (1) most Eucalyptus genes are expressed in xylem; (2) most genes expressed in species-specific way constitutes genes with unknown functions and are interesting targets for future studies; (3) relevant differences were observed in the phenylpropanoid pathway: E. grandis xylem presents higher expression of genes involved in lignin formation whereas E. urophylla seems to deviates the pathway towards flavonoid formation; (4) stress-related genes are considerably more expressed in E. urophylla, suggesting that these genes may contribute to its robustness. The comparison of these three transcriptomes indicates the molecular signatures underlying some of their distinct wood characteristics. This information may contribute to the understanding of xylogenesis, thus increasing the potential of genetic engineering approaches aiming at the improvement of Eucalyptus forest plantations productivity.1420

Immediate response of myocardium to pressure overload includes transient regulation of genes associated with mitochondrial bioenergetics and calcium availability

Ventricular hypertrophy is one of the major myocardial responses to pressure overload (PO). Most studies on early myocardial response focus on the days or even weeks after induction of hypertrophic stimuli. Since mechanotransduction pathways are immediately activated in hearts undergoing increased work load, it is reasonable to infer that the myocardial gene program may be regulated in the first few hours. In the present study, we monitored the expression of some genes previously described in the context of myocardial hypertrophic growth by using the Northern blot technique, to estimate the mRNA content of selected genes in rat myocardium for the periods 1, 3, 6, 12 and 48 h after PO stimuli. Results revealed an immediate switch in the expression of genes encoding alpha and beta isoforms of myosin heavy chain, and up-regulation of the cardiac isoform of alpha actin. We also detected transitory gene regulation as the increase in mitochondrial cytochrome c oxidase 1 gene expression, parallel to down-regulation of genes encoding sarco(endo)plasmic reticulum Ca+2 ATPase and sodium-calcium exchanger. Taken together, these results indicate that initial myocardial responses to increased work load include alterations in the contractile properties of sarcomeres and transitory adjustment of mitochondrial bioenergetics and calcium availability

Xylem transcription profiles indicate potential metabolic responses for economically relevant characteristics of Eucalyptus species

Abstract Background Eucalyptus is one of the most important sources of industrial cellulose. Three species of this botanical group are intensively used in breeding programs: E. globulus, E. grandis and E. urophylla. E. globulus is adapted to subtropical/temperate areas and is considered a source of high-quality cellulose; E. grandis grows rapidly and is adapted to tropical/subtropical climates; and E. urophylla, though less productive, is considered a source of genes related to robustness. Wood, or secondary xylem, results from cambium vascular differentiation and is mostly composed of cellulose, lignin and hemicelluloses. In this study, the xylem transcriptomes of the three Eucalyptus species were investigated in order to provide insights on the particularities presented by each of these species. Results Data analysis showed that (1) most Eucalyptus genes are expressed in xylem; (2) most genes expressed in species-specific way constitutes genes with unknown functions and are interesting targets for future studies; (3) relevant differences were observed in the phenylpropanoid pathway: E. grandis xylem presents higher expression of genes involved in lignin formation whereas E. urophylla seems to deviates the pathway towards flavonoid formation; (4) stress-related genes are considerably more expressed in E. urophylla, suggesting that these genes may contribute to its robustness. Conclusions The comparison of these three transcriptomes indicates the molecular signatures underlying some of their distinct wood characteristics. This information may contribute to the understanding of xylogenesis, thus increasing the potential of genetic engineering approaches aiming at the improvement of Eucalyptus forest plantations productivity

Busca por genes diferencialmente expressos em resposta a indução de hipertrofia ventricular em rato (Rattus norvegicus) atraves da tecnica de microarranjos de DNA

Orientador: Gonçalo Amarante Guimarães PereiraDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: Myocardial hypertrophy is one of the major responses to hemodynamic overload imposed by arterial hypertension. This elicits several histological and physiological alterations that affect the performance of the cardiac muscle as a whole. However, little is known about the molecular basis of the process, mainly because its multifactorial and polygenic trait. In this study, the DNA microarrays technique was adopted to identify genes directly involved in the establishment of myocardial hypertrophy. The experiments were based on the production of microarrays from 2304 clones of unknown identity derived from a non-normalized rat heart library. The microarrays were hybridized against cDNA targets synthesized after samples collect at short intervals (1, 3, 6, 12 and 48 hours) following hypertrophy induction by aorta constriction in rats (Rattus norvegicus). The results had confirmed the great potential of microarray technique for identification of differentially expressed genes in response to arterial hypertension, identifying the genes a-MHC, b-MHC and cardiac a-actin, previously described as involved in the process. More interesting, the gene of synaptopodin-2, protein associated with actin cytoskeleton and involved in stress fiber formation in response to mechanical stimuli in podocytes, and the gene of a precursor protein of amyloid beta A4, which is important because of its interaction with a protein that promotes the aggregation of components of MAPK (mitogen-activated protein kinase) cascade in a functional signaling module, were also identified. However, we concluded that it will be essential to utilize normalized libraries to reduce the redundancy of the selected genes, increasing the possibility to find novel genesAbstract: A hipertrofia do miocárdio é uma das principais respostas à sobrecarga hemodinâmica imposta ao coração em um quadro de hipertensão arterial, gerando diversas modificações histofisiológicas que afetam o desempenho do músculo cardíaco como um todo. Entretanto, pouco se sabe sobre a base molecular deste processo, uma vez que esta fisiopatologia possui um caráter poligênico e multicausal. O presente estudo utilizou a técnica de microarranjos de DNA para tentar identificar genes diretamente envolvidos no estabelecimento da hipertrofia cardíaca. Os experimentos basearam-se na produção de microarranjos a partir de 2304 fragmentos de DNA de seqüência desconhecida, provenientes de uma biblioteca não normalizada de ESTs (expressed sequence tags) de coração controle de rato. Esses microarranjos foram hibridados contra amostras de cDNAs sintetizadas a partir do mRNA coletado a intervalos curtos de tempo (1, 3, 6, 12 e 48 horas) após a indução de hipertrofia em ratos (Rattus norvegicus). Os resultados demonstraram que a técnica tem grande potencial para a identificação de genes diferencialmente expressos em resposta à hipertensão cardiovascular, tendo sido identificados os genes a-MHC, _bMHC e a-actina cardíaca, previamente descritos como envolvidos neste processo, bem como os genes da sinaptopodina-2, proteína associada à actina e envolvida na formação de fibras de estresse em resposta à estímulo mecânico em podócitos, não descrito anteriormente como expresso neste tecido, e da proteína precursora de amilóide beta A4, importante porque atua sobre uma proteína que promove a agregação de componentes da cascata das MAPKs (mitogen activated protein kinase) para formar um módulo sinalizatório funcional. Entretanto, observou-se que será essencial usar bibliotecas normalizadas para reduzir a redundância dos genes selecionados e aumentar a possibilidade de encontrar genes novosMestradoBioquimicaMestre em Biologia Funcional e Molecula

Para assegurar a saúde do corpo e da alma: prevenção e cura na Europa e no Ultramar do século XVI ao XVIII

O início do período moderno na Europa se caracterizou por uma excessiva formalização da vida pela sujeição a regras comportamentais, fundamentada na percepção de que “por meio da conduta, dos costumes, das maneiras do vestuário, do porte” definia-se o grau de inserção na “verdadeira cultura”. Concomitantemente a essa “modificação das sensibilidades” vivenciada pelo homem moderno, observou-se a crescente importância da moral e da religião, bem como da educação erudita para a civilidade e o ref..