The metabolism and role of free fatty acids in key physiological processes in insects of medical, veterinary and forensic importance

Abstract

Insects are the most widespread group of organisms and more than one million species have been described. These animals have significant ecological functions, for example they are pollinators of many types of plants. However, they also have direct influence on human life in different manners. They have high medical and veterinary significance, stemming from their role as vectors of disease and infection of wounds and necrotic tissue; they are also plant pests, parasitoids and predators whose activities can influence agriculture. In addition, their use in medical treatments, such as maggot therapy of gangrene and wounds, has grown considerably. They also have many uses in forensic science to determine the minimum post-mortem interval and provide valuable information about the movement of the body, cause of the death, drug use, or poisoning. It has also been proposed that they may be used as model organisms to replace mammal systems in research. The present review describes the role of free fatty acids (FFAs) in key physiological processes in insects. By focusing on insects of medical, veterinary significance, we have limited our description of the physiological processes to those most important from the point of view of insect control; the study examines their effects on insect reproduction and resistance to the adverse effects of abiotic (low temperature) and biotic (pathogens) factors.

Keywords: Adaptation to cold; Fatty acid transport protein; Free fatty acid; Insect physiology; Lipophorin; Polyunsaturated fatty acid.

Figure 1. The absorption and transport of FFAs in insect.

FFA, free fatty acid; FABP, fatty acid binding protein; FATP, fatty acid transport protein; LP, lipophorin; LP_R, lipophorin receptor; HDLp, high-density lipophorin particle; LDLp, low-density lipophorin particle; VHDLp, very high lipophorin particle.

Figure 2. The biosynthesis of FFAs in insect.

ACC, acetyl-CoA carboxylase; FAS, fatty acid synthase; ACSL, long-chain acyl-CoA synthetase; FAD, fatty acid desaturase; VLC FFAs, very long chain free fatty.