Flora das Culturas Agrícolas da Ilha de Santiago (cabo Verde)

Com o objectivo de caracterizar as comunidades vegetais que acompanham as culturas agrícolas de sequeiro e de regadio praticadas em Santiago e, particularmente, no vale da ribeira Seca, efectuaram-se 16 levantamentos titoecológicos ao longo deste curso de água e encostas sobranceiras. A inventaria@0 floristica revelou a presenta de 118 taro pertencenteas 3 3 familias. Analisaram-sea, inda,6 2 levantamentorse alizadose m diversosp ontosd a ilha, tendo sido identificados1 72t axa pertencenteas 42 familiasG. ramineae. Leguminosae e Compositue sao as famílias melhor representadasA. flora inventariadaC comparadac om a referida em trabalhos precedentesr,e alizadosp or outrosa utores,r evelandolao correnciad e, pelo menos,1 82t axa na flora infestante. Os levantamentos da ribeira Seca foram analisadosa travt5sd o programad e análise numérica TWINSPAN, que indicou a presentad e 4 agrupamentosv egetais distintos, cuja interpretacao,a tendendoà s característicase dáticas,c limáticase topográticasd os locais onde ocorrem,s ugeriua disponibilidadeh idrica comoo factorm aisd eterminantde as uac omposicáo. Palavras-chavefl:o ra, adventiciasd asc ulturasT, WINSPAN, ilhasd eC aboV erde, Santiago. In order to identify and to characterizeth e plant communitiesp resenat t the irrigated and dry cropso f ribeira Secav alley, it were established16 s amplep lots. The tloristic inventory has revealedt he presenteo f 118 tara belongingt o 33 families.I n addition,m ore 62 samplep lots,were establishedth roughoutt he island,w hich permittedt he identifkation of 172t ara from 42 families.G ramineae, CompQsitae &ndL eguminosae weret he mostr epresentativeosn es.T his flora is comparedw ith that referred in precedingw orksf rom othersa uthors,r evealingt he occurrence of, at least, 182 tma in the weed flora. The application of the TWINSPAN numerical analysis, to the plots in the ribeira Seca vallcy. has revealed the presente of 4 distinct plant communities, which were related with edaphic,c limatic and topographicf actors.T his analysiss uggestetdh at the water availability wa.s the mainf actor affecting the speciesc ompositionof the communities. Key-words:f lora weedsT, WINSPAN, CapeV erdei slandsS, antiago

Argon assisted chemical vapor deposition of CrO2_2: an efficient process leading to high quality epitaxial films

A comparative study of the structural, microstructural and magnetic properties of CrO$_2$ thin films grown onto (110) and (100) TiO$_2$ rutile single crystal substrates by chemical vapor deposition (CVD), using CrO$_3$ as chromium precursor and either oxygen or argon as carrier gas is presented. Our results show that growth under argon carrier gas leads to high quality CrO$_2$ epilayers with structural and magnetic properties similar to those obtained using the more standard oxygen carrier gas. Furthermore, we interpret the larger magnetic coercivity observed for the (110) oriented films in terms of their microstructure, in particular of the highest strain and edge roughness of the building structures of the CrO$_2$ epilayers, which are settled by the substrate crystallographic orientation.Comment: 27 pages, 2 tables, 8 figure

Analysis of return distributions in the coherent noise model

The return distributions of the coherent noise model are studied for the system size independent case. It is shown that, in this case, these distributions are in the shape of q-Gaussians, which are the standard distributions obtained in nonextensive statistical mechanics. Moreover, an exact relation connecting the exponent $\tau$ of avalanche size distribution and the q value of appropriate q-Gaussian has been obtained as q=(tau+2)/tau. Making use of this relation one can easily determine the q parameter values of the appropriate q-Gaussians a priori from one of the well-known exponents of the system. Since the coherent noise model has the advantage of producing different tau values by varying a model parameter \sigma, clear numerical evidences on the validity of the proposed relation have been achieved for different cases. Finally, the effect of the system size has also been analysed and an analytical expression has been proposed, which is corroborated by the numerical results.Comment: 14 pages, 3 fig

Effect of chronic exposure to aluminium on isoform expression and activity of rat (Na+/K+)ATPase

The ability of aluminum to inhibit the (Na+/K+)ATPase activity has been observed by several investigators. The (Na+/K+)ATPase is characterized by a complex molecular heterogeneity that results from the expression and differential association of multiple isoforms of both catalytic (alpha) and regulatory (beta) subunits. For instance, three main alpha (alpha(1), alpha(2) and alpha(3)) and three beta (beta(1), beta(2) and beta(3)) subunit isoforms exist in vertebrate nervous tissue, whereas only alpha(1) and beta(1) have been identified in kidney. However, no studies have focused on determining the change in (Na+/K+)ATPase isoforms caused by chronic exposure to aluminum and its relation with aluminum toxicity. In this study, adult male Wistar rats were submitted to chronic dietary AlCl3 exposure (0.03 g/day of AlCl3 for 4 months), and the activity and protein expression of (Na+/K+)ATPase isozymes were studied in brain cortex synaptosomes and in kidney homogenates. The intracellular levels of adenine nucleotides, plasma membrane integrity, and aluminum accumulation were also studied in brain synaptosomes. Aluminum accumulation upon chronic dietary AlCl3 administration significantly decreased the (Na+/K+)ATPase activity measured in the presence of nonlimiting Mg-ATP concentrations, without compromising protein expression of alpha-subunit isoforms in brain and kidney. Aluminum-induced synaptosomal (Na+/K+)ATPase inhibition was due to a reduction in the activity of isozymes containing alpha(1)-alpha(2) and alpha(3)-subunits. The onset of enzyme inhibition was accompanied by a decrease of the (Na+/K+)ATPase sensitivity to submicromolar concentrations of ouabain, and it preceded major damage in plasma membrane integrity and energy supply, as revealed by the analysis of lactate dehydrogenase leakage and endogenous adenine nucleotides. The data suggest that, during chronic dietary exposure to AlCl3, brain (Na+/K+)ATPase activity drops, even if no significant alterations of catalytic subunit protein expression, cellular energy depletion, and changes in cell membrane integrity are observed. Implications regarding underlying mechanisms of aluminum neurotoxicity are discussed.FCTPOCTI/BSE/46721/2002BD/21343/9

The role of endoplasmic reticulum in amyloid precursor protein processing and trafficking: implications for Alzheimer's disease

The endoplasmic reticulum (ER) is the principal organelle responsible for the proper folding/processing of nascent proteins and perturbed ER function leads to a state known as ER stress. Mammalian cells try to overcome ER stress through a set of protein signaling pathways and transcription factors termed the unfolded protein response (UPR). However, under unresolvable ER stress conditions, the UPR is hyperactivated inducing cell dysfunction and death. The accumulation of misfolded proteins in the brain of Alzheimer's disease (AD) patients suggests that alterations in ER homeostasis might be implicated in the neurodegenerative events that characterize this disorder. This review discusses the involvement of ER stress in the pathogenesis of AD, focusing the processing and trafficking of the AD-related amyloid precursor protein (APP) during disease development. The potential role of ER as a therapeutic target in AD will also be debated

Implantação do laboratório de moscas-das-frutas na Empresa Baiana de Desenvolvimento Agrícola.

A fruticultura baiana vem se destacando como um dos mais importantes segmentos da agropecuária. Entretanto, a ocorrência de pragas é considerada como um dos entraves ao seu desenvolvimento, e em especial à exportação de frutas ao mercado externo.PDF. 151_11

Entangled effects of allelic and clonal (genotypic) richness in the resistance and resilience of experimental populations of the seagrass Zostera noltii to diatom invasion

Background - The relationship between species diversity and components of ecosystem stability has been extensively studied, whilst the influence of the genetic component of biodiversity remains poorly understood. Here we manipulated both genotypic and allelic richness of the seagrass Zostera noltii, in order to explore their respective influences on the resistance of the experimental population to stress. Thus far intra-specific diversity was seldom taken into account in management plans, and restoration actions showed very low success. Information is therefore needed to understand the factors affecting resistance and resilience of populations. Results Our results show a positive influence of both allelic and genotypic richness on the resistance of meadows to environmental perturbations. They also show that at the low genotypic (i.e. clonal) richness levels used in prior experimental approaches, the effects of genotypic and allelic richness could not be disentangled and allelic richness was a likely hidden treatment explaining at least part of the effects hitherto attributed to genotypic richness. Conclusions Altogether, these results emphasize the need to acknowledge and take into account the interdependency of both genotypic and allelic richness in experimental designs attempting to estimate their importance alone or in combination. A positive influence of allelic richness on resistance to perturbations, and of allelic richness combined with genotypic richness on the recovery (resilience) of the experimental populations is supported by differential mortality. These results, on the key species structuring of one of the most threatened coastal ecosystem worldwide, seagrass meadows, support the need to better take into account the distinct compartments of clonal and genetic diversity in management strategies, and in possible restoration plans in the future.Peer Reviewe

Criação e manutenção de colônias de Ceratitis capitata e Anastrepha obliqua para estudos de biologia e ecologia da praga na Bahia.

As moscas-das-frutas são consideradas pragas agrícolas de uma extensa variedade de frutíferas apresentando algumas características biológicas que as favorecem, como elevado potencial biótico, habilidade de se dispersarem no meio ambiente e de se adaptarem a novos hospedeiros (GALLO et al., 1993). Essas espécies são responsáveis por danos diretos e indiretos, sendo consideradas um dos principais problemas fitossanitários da fruticultura brasileira e mundial (MORGANTE, 1991).Em paralelo aconteceram também os seguintes eventos: V Seminário de Pesquisa do Recôncavo da Bahia; V Seminário Estudantil de Pesquisa da UFRB; V Seminário da Pós-Graduação da UFRB; II Seminário Regional de Pesquisa da EBDA; 5ª Jornada Científica da Embrapa Mandioca e Fruticultura; VIII Seminário Estudantil de Pesquisa e Extensão da FAMAM; Semana de Ciência, Tecnologia e Inovação no Agronegócio; Fórum de Gestores de Iniciação Científica e Tecnológica da Bahia; II Simpósio Baiano de Defesa Agropecuária; I Semana de Educação Tutorial da UFRB

Comparative study of the biological behaviour in hamster of two isolates of leishmania characterized respectively as L. major-like and L. donovani

Hamster inoculated intraperitoneally with 1 x 10(7) parasites of L. donovani and L. major-like of the New World were studied in groups of 15, 30, 60 and 90 days of infection. The parasite load and density showed progressive increase with the evolution of the infection and was higher in the L. donovani groups than in the L. major-like groups. The L. major-like groups showed parasite density higher in the spleen than in the liver and was similar in both organs in L. donovani groups. The histopathology showed a diffuse marked hyperplasia and hypertrophy of the reticuloendothelial system with high parasitism in the L. donovani groups while there was focal involvement of these organs in L. major-like groups, forming nodules of macrophages that were scantly parasitised. The biological behaviour could be useful in the preliminary studies of Leishmania strain in regional laboratories and understanding the histopathology of lesions caused by different leishmania species.Experimentos utilizando-se hamsters inoculados intraperitonealmente com 1 x 10(7) parasitas de 2 cepas, L. donovani (MHOM/BR/72/LD 46) e L. major-like (MCAN/BR/73/LD 70) isoladas no Novo Mundo foram realizados e estudados em grupos de 15, 30, 60 e 90 dias de infecção. A carga e a densidade parasitária mostraram progressivo aumento com a evolução da infecção e foi maior nos grupos inoculados com L. donovani do que nos grupos inoculados com L. major-like. Os grupos inoculados com L. major-like mostraram densidade parasitária maior no baço que no fígado e foram semelhantes em ambos os órgãos nos grupos inoculados com L. donovani. A histopatologia mostrou intensa e difusa hyperplasia e hipertrofia do sistema reticuloendotelial com alto parasitismo nos grupos inoculados com L. donovani, enquanto foi encontrado envolvimento focai nestes órgãos nos grupos inoculados com L. major-like, formando nódulos de macrófagos discretamente parasitados. O comportamento biológico seria útil em estudos preliminares de identificação de cepas de Leishmania em laboratórios regionais e na compreensão da histopatologia das lesões causadas por diferentes espécimes de leishmanias