Nutrient Schedule Research Articles

A model for 3-dimensional growth of bladder cancers to investigate cell-matrix interactions

Elucidating the mechanisms by which the phenotype of cancer cells is modulated by the extracellular matrix (ECM) potentially identifies mechanisms that could be exploited for cancer control. Three readily available bladder cancer cell lines of different aggressiveness were grown on a bioscaffold material (Small Intestine Submucosa: SIS) under a variety of media and nutrient schedules to determine the influence of epigenetic factors on phenotype. The aggressive TCCSUP and J82 lines displayed an invasive phenotype when fed twice weekly with medium containing 10% fetal calf serum (FCS), but grew as a layered, noninvasive structure when fed daily with the same nutrient. The papillary RT4 cells grew as a nearly normal appearing layered phenotype when fed with medium containing 10% FCS, regardless of the feeding schedule. The papillary phenotype appeared only when the fetal calf serum concentration was reduced to 1% and the cells were fed twice weekly. Immunohistochemical staining showed E-cadherin was detected in the nucleus of the TCCSUP line rather than on the cell periphery, thus, demonstrating that normalization of the TCCSUP line into a layered phenotype did not alter the fundamental dysregulation of the cadherin-B-catenin-cytoskeleton complex. In contrast, in the RT4 cells the biomarker was distributed discretely around the cell periphery in 10% fetal calf serum but in the nucleus in 1% fetal calf serum and twice weekly feeding. Modulating the phenotype of cancer cells from invasive to noninvasive through manipulation of matrix and nutrient components presents a model system for identifying the key factors involved in invasiveness and may identify new therapeutic targets and markers.

Preferential leaching of nitrate, chloride and phosphate in an Australian clay soil

This paper investigates leaching of water and nutrients (NO‐ 3, Cl‐, PO3‐ 4) from the unsaturated layer in an Australian soil using a multisegment percolation system (MPS). Large undisturbed soil cores were collected from a clay‐based, basaltic plain, agricultural soil at Grassmere, 300 km west of Melbourne, Australia. Significant heterogeneity (or preferential flow) of effluent moisture and solutes was detected (one‐way ANO VA, p < 0.001). Fifty percent of the applied nitrate and chloride leached from the soil core within three days after initial application. Hundred percent of the applied nitrate and chloride leached from the soil core within 8 days after application. These results indicate little incorporation into the soil matrix, and possible denitrification or mineralisation. In contrast, after 18 days, less than 1 % of the total applied phosphates leached from the soil, indicating strong adsorption. Our experiments indicate considerable heterogeneity in water flow patterns and solute leaching on a small spatial scale. Very rapid transport of nitrate and chloride through the soil was evident, in comparison phosphate leaching was negligible. These results have important implications for the management of nutrient schedules in agricultural soils, particularly those located in the Western District of Victoria, Australia.