RESUMO

The biotechnological value of macroalgae for screening assays of thrombin generation-TG using sulfated polysaccharides-SPs as substitutes to heparin has been poorly explored. Five Brazilian species of macroalgae (Gracilaria birdiae, Acanthophora muscoides, Halymenia sp., Caulerpa cupressoides and C. racemosa) wereanalyzed and compared for their abundance, physical-chemical characteristics and in vitro anticoagulant assays of activated partial thromboplastin time-APTT, prothrombin time-PT and TG. Papain extraction yielded (p 100 kDa. These procedures,combined with the use of Stains-All, also indicated nonSPs. APTTs ranged from 2.81 (A. muscoides) to 21.30 IU(Halymenia sp.) vs. heparin (193 IU), and were dependent on sulfation of the crude SPs. PT was not altered. Withrespect to TG assay, crude SPs modified concentration-dependent and independently from molecular mass TGby both intrinsic/extrinsic pathways in 60-fold diluted human plasma, with total intrinsic inactivation using crudeSPs from A. muscoides in parallel to heparin (p < 0.05). Thrombosis in vitro is differentially modulated by distinctcrude SPs from Brazilian seaweeds.

O valor biotecnológico das macroalgas para ensaios de varredura de geração de trombina-GT pouco tem sido explorado usando polissacarídeos sulfatados-PSs como substitutos à heparina. Foramanalisadas e comparadas cinco espécies brasileiras de macroalgas (Gracilaria birdiae, Acanthophora muscoides, Halymenia sp., Caulerpa cupressoides e C. racemosa) quanto à abundância, às característicasfísico-químicas e os ensaios anticoagulantes in vitro de tempo de tromboplastina parcial ativada-TTPA, aotempo de protrombina-TP e a GT. A extração com papaína rendeu (p 100 kDa. Esses procedimentos,combinados ao uso de azul de toluidina/Stains-All, indicaram também polissacarídeos-não sulfatados. OsTTPAs foram dependentes da sulfatação dos PSs brutos e variaram de 2,81 (A. muscoides) a 21,30 UI (Halymenia sp.) vs. heparina (193 UI). O TP não foi alterado. Com respeito ao ensaio de GT, os PSs brutos modificaram, dependente de concentração e independentemente de massa molecular, GT pelas viasintrínseca/extrínseca no plasma humano diluído 60 vezes, com inativação intrínseca total usando PSs brutosde A. muscoides em paralelo à heparina (p < 0,05). A trombose in vitro é modulada diferencialmente porPSs brutos distintos de algas marinhas brasileiras.

Assuntos

RESUMO

The biotechnological value of macroalgae for screening assays of thrombin generation-TG using sulfated polysaccharides-SPs as substitutes to heparin has been poorly explored. Five Brazilian species of macroalgae (Gracilaria birdiae, Acanthophora muscoides, Halymenia sp., Caulerpa cupressoides and C. racemosa) wereanalyzed and compared for their abundance, physical-chemical characteristics and in vitro anticoagulant assays of activated partial thromboplastin time-APTT, prothrombin time-PT and TG. Papain extraction yielded (p < 0.001) from 0.66±0.03% (C. racemosa) to 41.60±1.10% (Halymenia sp.) of crude SPs varying sulfate (8.41-42.60%) and total sugars (47.80-70.53%). Crude SPs showed difference in mobility and resolution pattern by agarose electrophoresis, while polyacrylamide analysis revealed SPs of > 100 kDa. These procedures,combined with the use of Stains-All, also indicated nonSPs. APTTs ranged from 2.81 (A. muscoides) to 21.30 IU(Halymenia sp.) vs. heparin (193 IU), and were dependent on sulfation of the crude SPs. PT was not altered. Withrespect to TG assay, crude SPs modified concentration-dependent and independently from molecular mass TGby both intrinsic/extrinsic pathways in 60-fold diluted human plasma, with total intrinsic inactivation using crudeSPs from A. muscoides in parallel to heparin (p < 0.05). Thrombosis in vitro is differentially modulated by distinctcrude SPs from Brazilian seaweeds.(AU)

O valor biotecnológico das macroalgas para ensaios de varredura de geração de trombina-GT pouco tem sido explorado usando polissacarídeos sulfatados-PSs como substitutos à heparina. Foramanalisadas e comparadas cinco espécies brasileiras de macroalgas (Gracilaria birdiae, Acanthophora muscoides, Halymenia sp., Caulerpa cupressoides e C. racemosa) quanto à abundância, às característicasfísico-químicas e os ensaios anticoagulantes in vitro de tempo de tromboplastina parcial ativada-TTPA, aotempo de protrombina-TP e a GT. A extração com papaína rendeu (p < 0,001) de 0,66±0,03%(C. racemosa) a 41,60±1,10% (Halymenia sp.) de PSs brutos variando sulfato (8,41-42,60%) e açúcarestotais (47,80-70,53%). Os PSs brutos mostraram diferenças na mobilidade e resolução por eletroforese emagarose, enquanto pela análise em poliacrilamida revelou PSs brutos de >100 kDa. Esses procedimentos,combinados ao uso de azul de toluidina/Stains-All, indicaram também polissacarídeos-não sulfatados. OsTTPAs foram dependentes da sulfatação dos PSs brutos e variaram de 2,81 (A. muscoides) a 21,30 UI (Halymenia sp.) vs. heparina (193 UI). O TP não foi alterado. Com respeito ao ensaio de GT, os PSs brutos modificaram, dependente de concentração e independentemente de massa molecular, GT pelas viasintrínseca/extrínseca no plasma humano diluído 60 vezes, com inativação intrínseca total usando PSs brutosde A. muscoides em paralelo à heparina (p < 0,05). A trombose in vitro é modulada diferencialmente porPSs brutos distintos de algas marinhas brasileiras.(AU)

Assuntos

RESUMO

Climate change is a global phenomenon that is considered an important threat to marine ecosystems. Ocean acidification and increased seawater temperatures are among the consequences of this phenomenon. The comprehension of the effects of these alterations on marine organisms, in particular on calcified macroalgae, is still modest despite its great importance. There are evidences that macroalgae inhabiting highly variable environments are relatively resilient to such changes. Thus, the aim of this study was to evaluate experimentally the effects of CO2-driven ocean acidification and temperature rises on the photosynthesis of calcified macroalgae inhabiting the intertidal region, a highly variable environment. The experiments were performed in a reef mesocosm in a tropical region on the Brazilian coast, using three species of frondose calcifying macroalgae (Halimeda cuneata, Padina gymnospora, and Tricleocarpa cylindrica) and crustose coralline algae. The acidification experiment consisted of three treatments with pH levels below those occurring in the region (-0.3, -0.6, -0.9). For the temperature experiment, three temperature levels above those occurring naturally in the region (+1, +2, +4°C) were determined. The results of the acidification experiment indicate an increase on the optimum quantum yield by T. cylindrica and a decline of this parameter by coralline algae, although both only occurred at the extreme acidification treatment (-0.9). The energy dissipation mechanisms of these algae were also altered at this extreme condition. Significant effects of the temperature experiment were limited to an enhancement of the photosynthetic performance by H. cuneata although only at a modest temperature increase (+1°C). In general, the results indicate a possible photosynthetic adaptation and/or acclimation of the studied macroalgae to the expected future ocean acidification and temperature rises, as separate factors. Such relative resilience may be a result of the highly variable environment they inhabit.

Assuntos