Re-descriptions of Isospora ameivae Carini, 1932 in the Teiid Lizard Ameiva ameiva and Isospora hemidactyli Carini, 1936 in the Gecko Hemidactylus mabouia, with Particular Reference to their Endogenous Stages

Redescriptions are given of the mature oocysts of Isospora ameivae Carini, 1932, from the teiid lizard Ameiva ameiva, and Isospora hemidactyli Carini,1936 from the gecko Hemidactylus mabouia, in north Brazil. The endogenous stages of the two parasites in the small intestine are described. Those of I. ameivae are intracytoplasmic, whereas those of I. hemidactyli are intranuclear.

Haematozoan parasites of the lizard Ameiva ameiva (Teiidae) from Amazonian Brazil: a preliminary note

Three different haematozoan parasites are described in the blood of the teiid lizard Ameiva ameiva Linn. from North Brazil: one in the monocytes and the other two in erythrocytes. The leucocytic parasite is probably a species of Lainsonia Landau, 1973 (Lankesterellidae) as suggested by the presence of sporogonic stages in the internal organs, morphology of the blood forms (sporozoites), and their survival and accumulation in macrophages of the liver. One of the erythrocytic parasites produces encapsulated, stain-resistant forms in the peripheral blood, very similar to gametocytes of Hemolivia Petit et al., 1990. The other is morphologically very different and characteristically adheres to the host-cell nucleus. None of the parasites underwent development in the mosquitoes Culex quinquefasciatus and Aedes aegypti and their behaviour in other haematophagous hosts is under investigation. Mixed infections of the parasites commonly occur and this often creates difficulties in relating the tissue stages in the internal organs to the forms seen in the blood. Concomitant infections with a Plasmodium tropiduri-like malaria parasite were seen and were sometimes extremely heavy.

Activation of a P2Y4-like purinoceptor triggers an increase in cytosolic [Ca2+] in the red blood cells of the lizard Ameiva ameiva (Squamata, Teiidae)

An increasing number of pathophysiological roles for purinoceptors are emerging, some of which have therapeutic potential. Erythrocytes are an important source of purines, which can be released under physiological and physiopathological conditions, acting on purinergic receptors associated with the same cell or with neighboring cells. Few studies have been conducted on lizards, and have been limited to ATP agonist itself. We have previously shown that the red blood cells (RBCs) of the lizard Ameiva ameiva store Ca2+ in the endoplasmic reticulum (ER) and that the purinergic agonist ATP triggers a rapid and transient increase of [Ca2+]c by mobilization of the cation from internal stores. We also reported the ability of the second messenger IP3 to discharge the ER calcium pool of the ER. Here we characterize the purinoceptor present in the cytoplasmic membrane of the RBCs of the lizard Ameiva ameiva by the selective use of ATP analogues and pyrimidine nucleotides. The nucleotides UTP, UDP, GTP, and ATPgammaS triggered a dose-dependent response, while interestingly 2MeSATP, 2ClATP, alpha, ß-ATP, and ADP failed to do so in a 1- to 200-µm con- centration. The EC50 obtained for the compounds tested was 41.77 µM for UTP, 48.11 µM for GTP, 53.11 µM for UDP, and 30.78 µM for ATPgammaS. The present data indicate that the receptor within the RBCs of Ameiva ameiva is a P2Y4-like receptor due to its pharmacological similarity to the mammalian P2Y4 receptor.

Contribuição ao conhecimento de Thubunaea dactyluris karve, 1938 (Nematoda, Spiruroidea)

Na presente nota, redescrevemos Thubunaea dactyluris karve, 1938, em novo hospedador e assinalamos a ocorrência deste gênero pela primeira vez no Brasil. O material é resultante de uma necrópsia feita em Ameiva ameiva (L.), proveniente da Praia do Anil, Município de Magé, Estado do Rio de Janeiro. Foram estudados 8 machos e 10 fêmeas. São apresentados 9 figuras e 1 quadro com as medidas correspondentes, mostrando as variações encontradas.

Intestinal Coccidia (Apicomplexa: Eimeriidae) of Brazilian Lizards. Eimeria carmelinoi n.sp., from Kentropyx calcarata and Acroeimeria paraensis n.sp. from Cnemidophorus lemniscatus lemniscatus (Lacertilia: Teiidae)

Eimeria carmelinoi n.sp., is described in the teiid lizard Kentropyx calcarata Spix, 1825 from north Brazil. Oocysts subspherical to spherical, averaging 21.25 x 20.15 µm. Oocyst wall smooth, colourless and devoid of striae or micropyle. No polar body or conspicuous oocystic residuum, but frequently a small number of fine granules in Brownian movement. Sporocysts, averaging 10.1 x 9 µm, are without a Stieda body. Endogenous stages characteristic of the genus: intra-cytoplasmic, within the epithelial cells of the ileum and above the host cell nucleus. A re-description is given of a parasite previously described as Eimeria cnemidophori, in the teiid lizard Cnemidophorus lemniscatus lemniscatus. A study of the endogenous stages in the ileum necessitates renaming this coccidian as Acroeimeria cnemidophori (Carini, 1941) nov.comb., and suggests that Acroeimeria pintoi Lainson & Paperna, 1999 in the teiid Ameiva ameiva is a synonym of A. cnemidophori. A further intestinal coccidian, Acroeimeria paraensis n.sp. is described in C. l. lemniscatus, frequently as a mixed infection with A. cnemidophori. Mature oocysts, averaging 24.4 x 21.8 µm, have a single-layered, smooth, colourless wall with no micropyle or striae. No polar body, but the frequent presence of a small number of fine granules exhibiting Brownian movements. Sporocysts 9 x 8, without a Stieda body. Endogenous stages epicytoplasmic, characteristic of the genus, in the upper ileum. The importance of a study of the endogenous stages of eimeriid coccidia is discussed.