Development of Schizont Stages of <em>Toxoplasma gondii</em> in Primary Cell Culture of Feline Enterocytes

Intestinal epithelial cell cultures are a potentially applicable model for investigating enteropathogens such as the protozoan Toxoplasma gondii, the etiological agent of toxoplasmosis. Felids such as domestic cats are the only known definitive hosts where the parasite undergoes sexual reproduction, which occurs in the enterocytes. Primary feline intestinal epithelial cell (FIEC) cultures were obtained from the fetal small gut of felines, and the epithelial nature of these cells was confirmed by the revelation of cytokeratin and intestinal alkaline phosphatase content by fluorescence microscopy, besides alignment, microvilli, and adherent intercellular junctions by ultrastructural analysis. FIECs infected with T. gondii bradyzoite forms showed that the parasite:cell ratio was determinant for establishing the lytic cycle and cystogenesis and the induction of schizont-like forms. Type C and D schizonts were identified by light and electron microscopies, which showed morphological characteristics like those previously described based on the analysis of cat intestines experimentally infected with T. gondii. These data indicate that FIECs simulate the microenvironment of the felid intestine, allowing the development of schizogony and classic endopolygeny. This cellular framework opens new perspectives for the in vitro investigation of biological and molecular aspects involved in the T. gondii enteric cycle

Curso semipresencial promove reflexão sobre a prática no ensino de álgebra

Este artigo tem origem na satisfação do grupo de Álgebra, do Setor Matemática, do Projeto Fundão, ao terminar duas edições de um curso semipresencial sobre ensino de Álgebra para professores e futuros professores do Estado do Rio de Janeiro. Durante três anos, o grupo realizou um estudo sobre o desenvolvimento do pensamento algébrico que teve como resul-tado a publicação de um livro, em 2008, para servir de subsídio a professores interessados em inovar sua prática nas aulas de Álgebra, do 6º ano do ano, do Ensino Fundamental ao 3º ano do Ensino Médio. Como o conhecimento pedagógico do conteúdo (Shulman, 1986) desenvolvido ao longo do trabalho foi rico e significativo, o grupo resolveu compartilhá-lo com outros professores, por meio do curso. O seu sucesso em 2010fez com que o repetísse-mos, em 2011, para outros professores. Registramos aqui as ideias fundamentais sobre as quais giraram as reflexões do curso e observações, considerações e constatações possíveis a partir dele

Multidisciplinary Scientific Cruises for Environmental Characterization in the Santos Basin – Methods and Sampling Design

The Santos Basin (SB) is the main petroliferous basin in the Brazilian continental margin and one of the most studied marine areas in Brazil. However, historical data suggest that new efforts should be carried out to acquire quantitative biological data, especially in the deep sea, to establish the baseline of essential ocean variables in different ecosystems for future monitoring programs. The Brazilian energy company Petrobras planned and executed 24 oceanographic cruises over a period of 2 years to assess the benthic (SANSED cruise) and pelagic (SANAGU cruise) systems of the SB (356 days at sea in 2019 and 2021/2022). These efforts were part of the Santos Project, which comprised a comprehensive environmental study aimed at investigating benthic and pelagic variables to characterize ecology, biogeochemistry, thermohaline properties of water masses, and ocean circulation patterns, geomorphology, and sedimentology, as well as organic and inorganic chemistry. Here we present the detailed sampling designs and the field methods employed on board, during the SB scientific cruises. All sampling protocols were based on standardized approaches. For the benthos analyses, triplicate sediment samples were performed using a GOMEX-type box corer (0.25 m²) or a large modified Van Veen grab (0.75 m²) at 100 stations ranging from 25 to 2400 m depth. At each station, 25 geochemical and physico-chemical parameters were analyzed in addition to micro-, meio-, and macrofauna and living foraminifera samples. For the pelagic system, 60 stations were selected to investigate the plankton community, ranging in size from pico- to macroplankton, through vertical, horizontal, and oblique net hauls (20, 200, and 500 μm mesh size), as well as 25 biogeochemical parameters collected with an aid of a CTD-rosette sampler. Part of this scientific information also serves the Regional Environmental Characterization Project (PCR-BS) in support of Petrobras’ Santos Basin drilling licensing process led by the Brazilian Environmental Agency – IBAMA. This project contributes to the sustainable development of the SB, in line with the guidelines of the United Nations Decade of Ocean Science for Sustainable Development