Anurans are susceptible to contamination by pathogens or chemicals because they live in water, and these environments are subjected to degrading human activities. Escherichia coli is a Gram-negative bacteria, presenting lipopolysaccharide (LPS) in its external membrane, that confers pathogenicity. The aquatic environment is frequently contaminated by this microorganism, what could lead to the infection of the frogs and initiate an immune response against the pathogen. The Bufonidae family presents a peculiar organ, know as Bidder's organ, that is a rudimentary ovary that produce female germ cells. In the males, this organ is located in the cranial extremity of the testes and, in determined circumstances, it becomes functional. Evidences indicate that the infection can affect the reproduction of some species of frogs. Thus, we aim to evaluate the action of the lipopolysaccharide (LPS) from Escherichia coli in the Bidder's organ and testes, being based on the development of the germ cells of these organs, and to analyze the immune response of the animals exposed to the contamination for E. coli. For this, we will analyze the liver to describe and quantify cells of the immunologic system. We will use 24 males of Rhinella schneideri collected in the reproductive period (November of 2011). The frogs will be inoculated with LPS (3mg/Kg) and analyzed after 24h and after 48h of administration of the pathogen. The control group (n=6) will be administered with physiological solution, and they will be euthanized in intermediate period. Anatomical and histological description of the Bidder's organ, testes and liver will be realized and the biometric. The germ cells of Bidder's organ, testes will be quantified and immune cells in the liver described. Studies such as these are important to know the reproductive biology of anurans and to clarify some morphological and physiological aspects, as well as to evaluate general aspects of the immunologic system.
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