Aspectos imunológicos do caramujo Pomacea lineata (Spix, 1827) sob condições de estivação induzida

Abstract

Pomacea lineata (Spix, 1827) is a pulmonate gastropod that has a large dependence on humidity, Ampullaridae belongs to the family whose geographic distribution includes almost all the Neotropical Region , which inhabits waters of course slow and stagnate. Pulmonate gastropods have a conspicuous ecological feature, aestivation, which is a form of resistance and adaptation probably best defined as a survival strategy to cope with the arid conditions, but is also typically associated with lack of food availability, and often with high ambient temperatures. During these periods of aestivation some physiological aspects can be changed, as in molluscs, most of these is temperature dependent and can be altered by its variation, including the activity of the immune system. The innate immune system of invertebrates involves humoral and cellular response similar to that found in vertebrates. The cellular defenses occurs in combination with humoral defenses. Humoral responses include the production of reactive oxygen species (ROS) and nitric oxide (NO) and phenol oxidase enzyme activity, and cellular immune reactions are performed by hemocytes, performing, among other functions, encapsulation and phagocytosis of the pathogen. Thus, this research aimed to obtain information on some immunological parameters snail P. lineata in conditions of induced aestivation. The snails were induced to aestivation through the gradual withdrawal of water in the aquarium and abstention from food, getting in these conditions for 60 days. After this period, hemolymph of 40 individuals were collected for analysis of the total haemocyte count, measurement of nitric oxide, phenol oxidase activity and total protein. The results revealed that animals under aestivation showed a significant increase in the total number of hemocytes and measurement of nitric oxide, which may confer greater chance of survival.