https://www.selleckchem.com/products/capsazepine.html Photosynthesis is an important biochemical reaction that forms the basis of all food chains. Its efficiency is considered a key determinant of crop productivity. Therefore, improving photosynthetic efficiency has been a focus of intensive research. Here, we highlight simple approaches, recently reported by Chen et al. and Degen et al., to increase photosynthetic efficiency in field crops.The aim of this study was to identify the unknown transport mechanism of the extensively used monocarboxylate methionine feed supplement DL-methionine hydroxy analogue (DL-MHA) in rainbow trout intestine. Transport across the pyloric caeca (PC), midgut (MG), and hindgut (HG) regions were kinetically studied in Na+- and H+-dependent manners. Gene expression of monocarboxylate (MCTs) and sodium monocarboxylate transporters (SMCTs) were assessed. Results demonstrated that DL-MHA transport from 0.2-20 mM was Na+-dependent and obeyed Michaelis-Menten kinetics with low affinity in PC & MG in apical/basal pH of 7.7/7.7. Changes in apical/basal pH (6.0/6.0, 6.0/7.7, and 7.7/8.7) had insignificant effects on kinetics. In contrast, HG flux kinetics were only obtained in pH 7.7/8.7 or in the presence of lactate with medium affinity. Additionally, DL-MHA transport from 0-150 μM demonstrated the presence of a Na+-dependent high-affinity transporter in PC & MG. Conclusively, two distinct carrier-mediated DL-MHA transport mechanisms along the trout gut were found 1) in PC & MG apical transport was regulated by Na+-requiring systems that possibly contained low- and high-affinity transporters, and basolateral transport was primarily achieved through a H+-independent transporter; 2) in HG uptake was apically mediated by a Na+-dependent transporter with medium affinity, and basolateral exit was largely controlled by an H+-dependent transporter. Finally, two major methionine feed supplements, DL-MHA and DL-methionine (DL-Met) were compared to unders