Abstract We present two pollen diagrams from the semi-arid Caatinga of the Catimbau National Park, in Pernambuco and from a Mauritia palm forest in the Caatinga/Cerrado ecotone of southern Piauí, NE Brazil, spanning the last 10,000 cal. yrs BP and the last 1,750 cal yrs BP, respectively. These two records contain a signature of the local vegetation and permit the correlation of the pollen signal with regional climatic changes. The Catimbau record shows Zizyphus sp., a typical Caatinga taxon, in all three pollen zones indicating regional Caatinga vegetation and the predominance of local arboreal taxa adapted to high humidity from 10,000 to ca. 6,000 cal. yrs BP with a gradual tendency towards drier conditions revealed by a deposition hiatus between 6,000 to ca. 2,000 cal. yrs BP. This abrupt loss of sediments in both localities is interpreted as a consequence of the establishment of modern semi-arid climates. The subsequent return of humidity is signaled by increased sedimentation rates and 14C date inversions in agreement with high precipitation, revealed by σ18O ratios in speleothems from NE Brazil. Modern sediments deposited in the last 500 years reflect local conditions with the maintenance of humidity by geological faulting and surfacing water tables.

Ucides cordatus (Linnaeus, 1763) é um caranguejo de mangue hiper-hipo-regulador que possui brânquias responsáveis por processos respiratórios e osmorregulatórios. Apresentam também hepatopâncreas, que realizam digestão, absorção de nutrientes e detoxificação de metais tóxicos. Cada um desses órgãos possui células específicas que são importantes para estudos in vitro em biologia celular e transporte de íons e metais tóxicos. Visando estudar e caracterizar as células de cada órgão, estas foram separadas em um gradiente de sacarose (SG) de 10 a 40% e as células de cada gradiente foram caracterizadas usando o marcador de mitocôndria DASPEI (2-(4-dimethylaminostyryl)-N- ethylpyridinium iodide) e o corante Tricromo de Mallory. No SG de 20 e 40% para células branquiais e 30% para células hepatopancreáticas, foi observado um maior número de células coradas com DASPEI, indicando um maior número de mitocôndrias nessas células. Conclui-se que células branquiais presentes no SG de 20 e 40% são "Thin cells", responsáveis por processos respiratórios, e Ionócitos, responsáveis pelo transporte iônico, respectivamente. Para as células hepatopancreáticas, o SG de 30% é composto de células Fibrilares que possuem um maior número de transportadores de membrana para íons e nutrientes. Adicionalmente, o transporte do metal tóxico cádmio (Cd) em células hepatopancreáticas isoladas foi realizado para testar a integridade fisiológica das células isoladas e estudar o transporte entre os diferentes tipos celulares. Todas as células hepatopancreáticas transportaram Cd. Os resultados obtidos são um primeiro passo para trabalhos adicionais em células isoladas de importantes epitélios de troca em caranguejos, utilizando um método de separação simples e visando futuros estudos com cultura de células em caranguejos.

Ucides cordatus (Linnaeus, 1763) is a hypo-hyper-regulating mangrove crab possessing gills for respiratory and osmoregulatory processes, separated in anterior and posterior sections. They also have hepatopancreas, which is responsible for digestion and absorption of nutrients and detoxification of toxic metals. Each of these organs has specific cells that are important for in vitro studies in cell biology, ion and toxic metals transport. In order to study and characterize cells from gills and hepatopancreas, both were separated using a Sucrose Gradient (SG) from 10 to 40% and cells in each gradient were characterized using the vital mitochondrial dye DASPEI (2-(4-dimethylaminostyryl)-N- ethylpyridinium iodide) and Trichrome Mallory's stain. Both in 20 and 40% SG for gill cells and 30% SG for hepatopancreatic cells, a greater number of cells were colored with DASPEI, indicating a larger number of mitochondria in these cells. It is concluded that the gill cells present in 20% and 40% SG are Thin cells, responsible for respiratory processes and Ionocytes responsible for ion transport, respectively. For hepatopancreatic cells, the 30% SG is composed of Fibrillar cells that possess larger number of membrane ion and nutrient transporters. Moreover, the transport of toxic metal cadmium (Cd) by isolated hepatopancreatic cells was performed as a way of following cell physiological integrity after cell separation and to study differences in transport among the cells. All hepatopancreatic cells were able to transport Cd. These findings are the first step for further work on isolated cells of these important exchange epithelia of crabs, using a simple separation method and to further develop successful in vitro cell culture in crabs.