The active transport of monosaccharides by the intestine of Cryptochiton stelleri

Active transport of several monosaccharides was studied in the chiton, Cryptochiton stelleri, using the in vitro technique of Lawrence. Segments of intestine of Cryptochiton stelleri were found to be capable of transporting D-glucose, 3-0-methyl- D-glucose, and D-galactose against a concentration gradient. D-glucose and 3-m-G were transported in the anterior intestine but D-galactose was transported in the posterior intestine . D-mannose and D-fructose were not moved across the intestinal wall against a concentration gradient. The in vitro sac preparations of intestinal tissue were capable of maintaining transport activity with linear increase of serosal/mucosal concentration ratio for at least 12 hours. Anaerobic conditions brought about reversible inhibition of transport of 3-m-G in the anterior intestine; whereas, such conditions had only slight and irreversible effects upon transport of D-galactose in the posterior intestine. Transport of 3-m-G in the anterior intestine increased with temperature up to 25°C, at which point, irreversible damage occurred. [...]