Soil water status as a function of pressure (tension). Soil water status in natural soils can range from a flooded. condition to drainable gravitational water to plant available water. down to hydroscopic water. Tensions in natural soils do not. exceed -31,000; in this range, water is absorbed from the air.
Advanced Search. Tay-Sachs disease (the most severe form of Hexosaminidase A deficiency) is a progressive, fatal genetic condition that affects the nerve cells in the brain.
Tay-Sachs disease is caused by the absence or significantly reduced level of a vital enzyme called beta-hexosaminidase. It is the Hexosaminidase A (HEXA) gene in the DNA that provides instructions for making this enzyme. Without the correct amount of the HexA enzyme, a fatty substance or lipid called GM2 ganglioside accumulates abnormally in cells, especially in the nerve cells of the brain.