Ascazuri Ivan, Toraño Juan Cruz, Albanesi Camila, López Mañanes Alejandra, Michiels Maria Soledad
Departamento de Biologia, Instituto de Investigaciones Marinas y Costeras (IIMyC)-Universidad Nacional de Mar del Plata CONICET - FCEyN, Funes, Argentina.
J Fish Biol. 2025 Aug;107(2):511-519. doi: 10.1111/jfb.70061. Epub 2025 Apr 11.
The determination of the existence and level of activity of specific digestive enzymes is commonly used as a tool to understand the functioning of the digestive machinery. The aim of this study was to determine the existence and biochemical characteristics of aminopeptidase-N (APN) activity in the digestive tract of Oligosarcus jenynsii from Mar Chiquita coastal lagoon (Buenos Aires) and its possible modulation by abscisic acid (ABA). Individuals were collected in November 2022 from freshwater tributaries of the coastal lagoon using a beach seine net. Juveniles and adults were immediately placed on ice after capture, whereas additional groups of juveniles were transported to the laboratory for in vitro experiments. Juveniles and adults exhibited APN activity in the intestine and liver, which was active across a wide range of pH and temperature, and followed Michaelis-Menten kinetics. Bestatin inhibited the activity in the intestine in both stages, but it had no effect on the liver. Adults exhibited higher specific APN activity in the intestine compared to juveniles. The presence of ABA in vitro decreased APN activity in both intestine and liver from juveniles. These results suggest the presence of APN in both juveniles and adults, as well as its differential modulation by ABA in juveniles.
特定消化酶的存在及其活性水平的测定通常被用作了解消化机制功能的一种工具。本研究的目的是确定来自马尔基基塔沿海泻湖（布宜诺斯艾利斯）的詹氏寡脂鲤消化道中氨肽酶 - N（APN）活性的存在及其生化特性，以及脱落酸（ABA）对其可能的调节作用。2022年11月，使用沙滩围网从沿海泻湖的淡水支流中采集个体。幼鱼和成年鱼捕获后立即置于冰上，而另外几组幼鱼被运到实验室进行体外实验。幼鱼和成年鱼在肠道和肝脏中均表现出APN活性，该活性在广泛的pH和温度范围内均有活性，并遵循米氏动力学。抑肽素在两个阶段均抑制肠道中的活性，但对肝脏无影响。与幼鱼相比，成年鱼在肠道中表现出更高的特异性APN活性。体外ABA的存在降低了幼鱼肠道和肝脏中的APN活性。这些结果表明幼鱼和成年鱼中均存在APN，以及ABA对幼鱼的差异性调节作用。
