Fig. 5. Spatial distribution of Atlantic cod PepT1 mRNA in the digestive tract of adult fish. (A) A representative picture of Atlantic cod digestive tract. 1, stomach; 2, pyloric area; 3, pyloric caeca (inner segments); 4, pyloric caeca (outer segments); 5–10, six adjacent intestinal segments in the remainder of the digestive tract, starting after the pyloric area (segment 5) and ending with the anus (segment 10), and based on divisions of the three loops present in the dissected gut. The last segment (e.g. segment 10) also comprises the hindgut. Arrows indicate the incisions between the segments. (B) RT-PCR performed on equal amounts of total RNA (1.5 µg) isolated from the different segments of the digestive tract of Atlantic cod using PepT1-(top row) and EF1-specific (bottom row) primers. Progressive numbers (1 to 10) indicate the segments of the digestive tract indicated in A. Control (C), no RNA (H₂O instead) in RT (negative control); M, DNA markers (10 kb SmartLadder; Eurogentec).