Valorização da biomassa lenhocelulósica: estudo de sacarificação enzimática do cardo e da esteva

Dissertação de mestrado em Engenharia do ambiente. Instituto Politécnico de Beja, Escola Superior Agrária, 2013.A Cynara cardunculus e o Cistus ladanifer, são duas espécies bem adaptadas às condições edafoclimáticas do Alentejo, e uma alternativa aos materiais fósseis no contexto de biorrefinaria, visto serem biomassas lenhocelulósicas. No presente trabalho desenvolveu-se um estudo com a finalidade de utilizar as duas biomassas e perceber como se comportam na sacarificação enzimática da celulose, que efeitos têm os prétratamentos na eficiência da mesma e que efeito tem o recipiente onde se realiza a hidrólise. Foi ainda elaborado um desenho experimental com o cardo, com o objetivo de otimizar a sacarificação enzimática quanto à quantidade de sólidos, e enzimas a usar. Os resultados mostram que o cardo é mais sacarificável que a esteva e que os prétratamentos aumentaram a acessibilidade das enzimas, para a fração celulósica relativamente ao material não tratado. Para ambas as biomassas o pré-tratamento mais eficaz foi a explosão de vapor lavado com NaOH, tendo-se produzido 27,8 e 20,9 g/L de glucose para o cardo e esteva, respetivamente. A sacarificação da biomassa nos tubos “falcon”, foi menor do que nos tubos centrífuga e Erlenmeyer, que não apresentaram diferenças significativas. O valor máximo previsto para o CHA 130 pelo desenho experimental é de 31,7±1,0 g/L para CS=8, FPU=44,6, CBU=51,9

The extracellular matrix component hyaluronic acid supports hippocampal synaptic plasticity by modulating postsynaptic L-type Ca2+ channels.

Although the extracellular matrix plays an important role in regulating use-dependent synaptic plasticity, the underlying molecular mechanisms are poorly understood. Here, we examined the synaptic function of hyaluronic acid (HA), a major element of the extracellular matrix. Enzymatic removal of HA with hyaluronidase reduced nifedipine-sensitive whole-cell Ca2+ currents and Ca2+ transients mediated by L-type voltage-dependent Ca2+ channels (L-VDCCs) in individual dendritic shafts and spines of CA1 pyramidal cells, and abolished an L-VDCC-dependent component of long-term potentiation (LTP) at the CA3-CA1 synapses. Adding exogenous HA, either by bath perfusion or via local delivery near to recorded synapses, completely rescued this LTP component. In a heterologous expression system, HA increased currents mediated by Cav1.2 but not Cav1.3 subunit-containing L-VDCCs. Injection of hyaluronidase in the brain impaired contextual fear conditioning. Our observations unveil a previously unrecognized mechanism by which the perisynaptic HA-rich extracellular matrix influences use-dependent synaptic plasticity through regulation of dendritic Ca2+ channels

Potencial de rizobactérias no controle de Fusarium solani (Mart.) Sacc. em pepino (Cucumis sativum L.) Potential of rhizobacteria in the control of Fusarium solani (Mart.) Sacc. in cucumber (Cucumis sativum L.)

Rizobactérias, isoladas da rizosfera de diferentes hospedeiros foram selecionadas in vitro quanto ao antagonismo contra Fusarium solam agente causai da podridão radicular. In vitro, foram selecionadas 18 bactérias isoladas da rizosfera de plantas sadias de pepino e, destas, somente três foram eficientes em inibir consideravelmente o crescimento micelial do patógeno. Dois isolados de Bacillus subtilis e dois de Pseudomonas sp., antagônicos a outros fungos fitopatogênicos foram incluidos nos testes, os quais mostraram-se capazes de antagonizar F. solani. Em condições de casa-de-vegetação, B. subtilis, linhagem 0G, controlou totalmente o patógeno em todos os ensaios realizados. Promoção do crescimento de plantas foi verificada pela inoculação com linhagens 0G (B. subtilis), St. Barb. e CBPN (Pseudomonas sp).<br>Rhizobacteria, isolated from the rhizosphere of different hosts were selected in vitro, based on the antagonism against Fusarium solani, agent of root rot. In vitro, 18 bacterias were selected from rhizosphere of healthy plants of cucumber and, from those, only three were efficient in inhibiting the micelial growth of the pathogen. In these tests two isolates of Bacillus subtilis (0G and 5G), and two of Pseudomonas (CBPN and St Barb.), antagonistic to some pathogenic fungi, were included. These bolates also inhibited the growth of F solani. The bolate OG of B. subtilis reduced significantly the root rot of cucumber. Beneficial effects were obtained with the bolates St Barb., 0G and CBPN in relation to plant growth

CASP, the Alternatively Spliced Product of the Gene Encoding the CCAAT-Displacement Protein Transcription Factor, Is a Golgi Membrane Protein Related to Giantin

Large coiled-coil proteins are being found in increasing numbers on the membranes of the Golgi apparatus and have been proposed to function in tethering of transport vesicles and in the organization of the Golgi stack. Members of one class of Golgi coiled-coil protein, comprising giantin and golgin-84, are anchored to the bilayer by a single C-terminal transmembrane domain (TMD). In this article, we report the characterization of another mammalian coiled-coil protein, CASP, that was originally identified as an alternatively spliced product of the CUTL1 gene that encodes CCAAT-displacement protein (CDP), the human homologue of the Drosophila homeodomain protein Cut. We find that the Caenorhabditis elegans homologues of CDP and CASP are also generated from a single gene. CASP lacks the DNA binding motifs of CDP and was previously reported to be a nuclear protein. Herein, we show that it is in fact a Golgi protein with a C-terminal TMD and shares with giantin and golgin-84 a conserved histidine in its TMD. However, unlike these proteins, CASP has a homologue in Saccharomyces cerevisiae, which we call COY1. Deletion of COY1 does not affect viability, but strikingly restores normal growth to cells lacking the Golgi soluble N-ethylmaleimide-sensitive factor attachment protein receptor Gos1p. The conserved histidine is necessary for Coy1p's activity in cells lacking Gos1p, suggesting that the TMD of these transmembrane Golgi coiled-coil proteins is directly involved in their function