Abstract We previously reported that elevated extracellular calcium (Ca2+) levels increase bone morphogenetic protein 2 expression in human dental pulp (hDP) cells. However, it is unknown whether extracellular Ca2+ affects the expression of other growth factors such as fibroblast growth factor 2 (FGF2). Objective: The present study aimed to examine the effect of extracellular Ca2+ on FGF2 gene expression in hDP and immortalized mouse dental papilla (mDP) cells. Materials and Methods: Cells were stimulated with 10 mM CaCl2 in the presence or absence of cell signaling inhibitors. FGF2 gene expression was assessed using real-time polymerase chain reaction. The phosphorylation status of signaling molecules was examined by Western blotting. Results: Extracellular Ca2+ increased FGF2 gene expression in mDP and hDP cells. Gene expression of the calcium-sensing receptor and G protein-coupled receptor family C group 6 member A, both of which are extracellular Ca2+ sensors, was not detected. Ca2+-mediated Fgf2 expression was reduced by pretreatment with the protein kinase A (PKA) inhibitor H-89 or extracellular signal-regulated kinase (ERK) 1/2 inhibitor PD98059 but not by pretreatment with the protein kinase C inhibitor GF-109203X or p38 inhibitor SB203580. Extracellular Ca2+ increased PKA activity and ERK1/2 phosphorylation. Ca2+-induced PKA activity decreased by pretreatment with PD98059. Conclusions: These findings indicate that elevated extracellular Ca2+ levels led to increased Fgf2 expression through ERK1/2 and PKA in mDP cells and that this mechanism may be useful for designing regenerative therapies for dentin.

O estudo fitossociológico, se realizado em diferentes estratos verticais da floresta, fornece dados de grande valia para a compreensão da dinâmica da comunidade. Efetuou-se levantamento das espécies arbóreas presentes em diferentes estratos, em área de 6.000 m² de floresta madura, na Estação Ecológica dos Caetetus, Gália, SP. Foram utilizadas 60 parcelas de 10 x 10 m, para indivíduos com diâmetro do caule a 1,30 m acima do nível do solo (DAP) a partir de 5 cm (estrato superior); 10 x 2 m, para indivíduos com DAP entre 1 e 5 cm (estrato intermediário) e 60 sub-parcelas de 2 x 2 m, para indivíduos menores que 1 cm de DAP (estrato inferior). Verificou-se que a diversidade, a composição florística e a densidade relativa das espécies variam entre estratos. No estrato superior, com 1.080 indivíduos.ha-1 e área basal de 31,2 m².ha-1, encontraram-se 62 espécies (28 famílias), tendo sido as mais importantes, em ordem decrescente de IVI: Metrodorea nigra, Savia dictyocarpa, Ocotea indecora, Aspidosperma polyneuron e Trichilia catigua. O estrato intermediário apresentou-se com densidade de 3.525 indivíduos.ha-1, pertencentes a 30 espécies (17 famílias), sendo as mais importantes em ordem decrescente de IVI: Metrodorea nigra, Actinostemon concolor, Trichilia catigua, Aspidosperma polyneuron e Trichilia clausenii. No estrato inferior a densidade foi de 28.875 indivíduos.ha-1, pertencentes a 37 espécies (19 famílias), sendo as mais abundantes, em ordem decrescente de densidade relativa: Metrodorea nigra, Actinostemon concolor, Trichilia catigua, Aspidosperma polyneuron e Eugenia blastantha. Constatou-se que há espécies do estrato superior da floresta que não foram observadas em regeneração, especialmente heliófitas de estádios sucessionais iniciais (p. ex. Croton floribundus). Outras ocorreram com densidade relativa decrescente nos estratos inferiores (p. ex. Savia dictyocarpa e Ocotea indecora). Para outras espécies, as sementes germinaram, mas não se desenvolveram à sombra, estando ausentes no estrato intermediário (p. ex. Cariniana estrellensis). Observou-se, ainda, um grupo de espécies, de estádios sucessionais mais avançados, que apresentaram a mesma densidade relativa em todos os estratos (p. ex. Metrodorea nigra e Aspidosperma polyneuron).

Phytosociology of distinct tree strata in tropical forests can be an important tool to understand community dynamics. The arboreal community of an area (6,000 m²) of mature forest was surveyed at the Caetetus Ecological Station, Gália, São Paulo State, Brazil. This protected area has one of the last significant forest remnants in Western São Paulo State, covering an area of 2,178.84 ha in a region where coffee plantation and pasture are dominant. Although the fragment has been protected against fire and exploitation for many years, there are visible edge effects. The sampling area in this study was intended to be representative of the original primary forest, free from edge effects. The arboreal community was divided into three strata: DBH equal to or higher than 5 cm (upper), DBH between 1 and 5 cm (intermediate) and DBH below 1 cm (lower). In each layer, 60 permanent plots, with different sizes were installed, being: 10 x 10 m (upper layer); 10 x 2 m (intermediate layer) and 2 x 2 m (lower layer). The upper stratum had 1,080 ind.ha-1, 62 species (28 families), being the most important (decreasing order): Metrodorea nigra, Savia dictyocarpa, Ocotea indecora, Aspidosperma polyneuron and Trichilia catigua. The intermediate stratum had 3,525 ind.ha-1, 30 species (17 families), being the most important: Metrodorea nigra, Actinostemon concolor, Trichilia catigua, Aspidosperma polyneuron and Trichilia claussenii. The density in the lower stratum was 28,875 ind.ha-1, from 37 species (19 families), being the most abundant, in decreasing relative density: Metrodorea nigra, Actinostemon concolor, Trichilia catigua, Aspidosperma polyneuron and Eugenia blastantha. Some of the species of the upper stratum was absent in the other strata, especially heliophytes, typical from early sucessional stages (e.g. Croton floribundus). Other species had decreasing importance values from the upper to the lower stratum (e.g. Savia dictyocarpa and Ocotea indecora). There were species whose seeds germinated but plants did not grow in the shade (e.g. Cariniana estrellensis). Finally, there was a group of species, typical from late successional stages, that had similar relative density in all strata, e.g. Metrodorea nigra and Aspidosperma polyneuron.