Influence of the shoot density of Halodule wrightii Ascherson from rocky and sandy habitats on associated macroalgal communities

This study evaluated the influence of the shoot density of the shoal grass Halodule wrightii on the composition of the associated algal community, in rocky and sandy habitats on the coast of Ceará in northeastern Brazil. The phycological community included 18 species in 10 families, members of Rodophyta (72.2%), Chlorophyta (22.2%) and Phaeophyceae (5.5%). The largest proportion were epilithic (50%), followed by epiphytes on H. wrightii (38.4%), epipsammics (8%), and epiphytes on other algae (4%). Epiphytes on H. wrightii occurred mainly associated with rhizomes, but also tendrils of H. musciformis occurred attached to the leaves. The phycological community varied according to the density of H. wrightii, independently of particular characters of the meadows, although both habitat and other environmental variables seemed to influence the macroalgae composition and diversity. The rocky habitat was more diverse than the sandy habitat, but in the sandy habitat the shoal grass was important for algal settlement in areas where hard substrates were scarce or absent

Spatial and temporal variation in algal epiphyte distribution on Ulva sp. (Ulvales, Chlorophyta) from northern Patagonia in Argentina

In this stu, dy of northern Patagonia in Argentina, we examined the annual cycle of the epiphyte composition and abundance on Ulva sp. with respect to intertidal elevation, season and position on host. We found spatial segregation in most environmental gradients. Local environmental conditions, intertidal levels, seasons and portion of host thalli had specific patterns of algal epiphytic community. The host population exhibited seasonality and differential morphological attributes according to the intertidal elevation. Thalli of Ulva sp. had the highest maximum diameters and were heavier in spring and summer at the upper elevation. Epiphytes were more abundant growing on host thalli at middle elevations. Epiphytic Dinophyceae, Chlorophyceae and Cyanophyceae presented clear seasonality. Epiphyte abundances were related to periods with high seawater temperature, long days and high radiation. Lyngbya sp., Cocconeis sp., Navicula spp., Rhabdonema arcuatum, Stylonema alsidii and Myrionema strangulans had the highest frequency. The highest epiphyte abundance was observed in holdfasts, with M. strangulans having the highest frequency and cover. These results are relevant to commercial aquaculture ventures for food and feed sources and application in bioremediation.Fil: Gauna, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Escobar, Juan Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Odorisio, Mariangeles. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Caceres, Eduardo Jorge. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Parodi, Elisa Rosalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentin

Blockade of enzyme activity inhibits tissue transglutaminase-mediated transamidation of alpha-synuclein in a cellular model of Parkinson's disease

Transamidation of α-synuclein by the Ca(2+)-dependent enzyme tissue transglutaminase (tTG, EC 2.3.2.13) is implicated in Parkinson's disease (PD). tTG may therefore offer a novel therapeutic target to intervene in PD. Here we first evaluated the potency and efficacy of three recently developed irreversible active-site inhibitors of tTG (B003, Z006 and KCC009) to inhibit tTG activity in vitro and in living cells. In vitro, all compounds were found to be full inhibitors of tTG activity showing a rank order of potency (defined by IC-50 values) of Z006>B003>KCC009. Upon Ca(2+) ionophore (A23187) induced activation of cellular tTG (measured by incorporation of the tTG-specific amine substrate 5-(biotinamido)pentylamine (BAP) into cellular proteins) in neuroblastoma SH-SY5Y cells, only Z006 (0.3-30 μM) retained the capacity to completely inhibit tTG activity. Under these conditions B003 (3-300 μM) only partially blocked tTG activity whereas KCC009 (3-100 μM) failed to affect tTG activity at any of the concentrations used. Z006 (30 μM) also blocked the tTG mediated incorporation of BAP into α-synuclein monomers and SDS-resistant multimers in vitro and in α-synuclein overexpressing SHSY5Y cells exposed to A23187 or the PD mimetic 1-methyl-4-phenylpyridine (MPP(+)). Moreover, Z006 (30 μM) substantially reduced formation of SDS-resistant α-synuclein multimers in SH-SY5Y cells exposed to A23187 or MPP(+) in the absence of BAP. We conclude that α-synuclein is a cellular substrate for tTG under conditions mimicking PD and blockade of tTG activity counteracts α-synuclein transamidation and aggregation in vitro and in living cells. Moreover, our cell model appears an excellent readout to identify candidate inhibitors of intracellular tTG