Arapaima gigas is an air-breathing giant fish of Amazonian rivers. Given its great economic and cultural importance, the aquaculture development of this species represents an evident solution to face the decline of wild populations. In captivity, reproduction occurs generally in large earthen ponds where stocks of a few tens of brooders are maintained together at the beginning of the rainy season (December-March in the Peruvian Amazon). Fry production relies on the spontaneous formation of male and female pairs, which build a nest, delimit a territory and guard the offspring for at least 20 days from other congeners and predators. However, as sex determination of A. gigas is not possible by morphological criteria, it is very difficult to optimize reproduction conditions and fry production in each pond, which seriously hampers the culture of this species. This situation prompted us to develop sexing methodologies based on (1) the detection of female specific plasma Vitellogenin (Vtg) using an enzyme immuno assay (EIA), and (2) the determination of plasma 17beta-estradiol and 11-ketotestosterone levels for immature specimens. The Vtg purification was performed by electro-elution after polyacrilamide gel electrophoresis (PAGE) from plasma of 17beta-estradiol treated A. gigas juveniles. Two different Vtg molecules were isolated, (Vtg(1) and Vtg(2)) with 184 and 112 kDa apparent molecular masses, respectively, and two antibodies were raised in rabbits for each Vtg molecule. Adult fish were 100% accurately sexed by Vtg EIA, while 100% of immature fish and 95% of adults were accurately sexed by 17beta-Estradiol and 11-Ketestosterone ratios. We also observed different color pattern development in male and female adult fish (6-year-olds) around the reproductive period.

Traditionally, hamsters are experimentally inoculated in the snout or the footpad. However in these sites an ulcer not always occurs, measurement of lesion size is a hard procedure and animals show difficulty to eat, breathe and move because of the lesion. In order to optimize the hamster model for cutaneous leishmaniasis, young adult male and female golden hamsters (Mesocricetus auratus) were injected intradermally at the dorsal skin with 1 to 1.5 x l0 7 promastigotes of Leishmania species and progression of subsequent lesions were evaluated for up to 16 weeks post infection. The golden hamster was selected because it is considered the adequate bio-model to evaluate drugs against Leishmania as they are susceptible to infection by different species. Cutaneous infection of hamsters results in chronic but controlled lesions, and a clinical evolution with signs similar to those observed in humans. Therefore, the establishment of the extent of infection by measuring the size of the lesion according to the area of indurations and ulcers is feasible. This approach has proven its versatility and easy management during inoculation, follow up and characterization of typical lesions (ulcers), application of treatments through different ways and obtaining of clinical samples after different treatments. By using this method the quality of animal life regarding locomotion, search for food and water, play and social activities is also preserved. Video LinkThe video component of this article can be found at http://www.jove.com/video/3533/ Protocol 1. Infection of Hamsters AnimalsInbred female and male golden hamsters (Mesocricetus auratus), 6-8 weeks, weighing 140-160 g are used. They are housed at the animal facility, in temperature-controlled accommodation, fed with standard rodent dried food and provided with water ad libitum. All the procedures involving animals are approved by the institutional Ethical Committee for Experimental Animal Use. Before experimental infection with dermotropic Leishmania parasites animals are sexed, marked and weighted according to standardized procedures. For sexing, animals are inspected for distinctive features such as the visualization of the mammary line and the short ano-genital distance in females, or the visualization of testicles and a greater distance between the anus and foreskin in males. Then, animals are marked by ear piercing or by staining an area of the skin with a swab soaked in picric acid. For ear perforation, after clean with 70% alcohol the ear is pierced using an ear punch for rodents. A region with blood vessels must be avoided. Sedation or anesthesia with a mixture 9:1 of Ketamine (50 mg/kg) and Xilacine (20 mg/kg) intraperitoneally in a volume of 260-300μl 25-G needle is recommended. Finally, animals are weighed by placing them in a trap or box that is conditioned on a precision balance. ParasitesPromastigotes of dermotropic Leishmania species, such as L. amazonensis, are cultured in biphasic Novy-MacNeal-Nicolle (NNN) culture medium at 26°C. Metacyclic (station...

An evaluation of the leishmanicidal activity in vitro and in vivo of hypericin, an expanded-spectrum photosensitizer found in Hypericum perforatum, is presented. Hypericin was evaluated against intracellular amastigotes in vitro of Leishmania (Viannia) panamensis. A topical formulation containing 0.5% hypericin was developed and assayed in vivo in a hamster model of cutaneous leishmaniasis. Results demonstrate that hypericin induces a significant antiamastigote effect in vitro against L. panamensis by decreasing the number of parasites inside infected cells. The topical formulation of 0.5% hypericin allows healing of L. panamensis-induced lesions upon a topical application of 40 mg/day plus visible-light irradiation (5 J/cm 2 , 15 min), twice a week for 3 weeks. Cutaneous leishmaniasis (CL) is a parasitic disease caused by protozoa of the genus Leishmania, which manifests as a chronic infection affecting mainly mononuclear phagocytes of the skin (1). The disease affects the poorest populations in 99 countries in tropical and subtropical regions of the world (2, 3). It is estimated that 14 million people are infected, 350 million are at risk, and there are about 1.5 million new cases per year (3, 4). The parasite is transmitted by the bite of an insect vector belonging to the genus Lutzomyia (in America) or Phlebotomus (in Europe, Asia, and Africa) in the subfamily Phlebotominae (5).Only three types of drugs are available to treat CL. They are the pentavalent antimonials (meglumine antimoniate and sodium stibogluconate), pentamidine isethionate, and miltefosine. Miltefosine is the only one available for oral administration (4). These medications are delivered at high doses and for long periods, thus leading to high toxicity. Therefore, their use is contraindicated in pregnant women, in patients with cardiovascular, renal, or hepatic disease, and in children with low body weight (6). Overall, the efficacy of these drugs varies between 55 and 98% depending on the compound and on the Leishmania species causing the clinical manifestation (7,8). However, their elevated toxicity encourages abandonment of treatment and consequently a decrease in the efficacy (9).More recently, photodynamic therapy (PDT) has emerged as an alternative to treat CL (10). This therapy is based on the application of a photosensitizing agent (PA) that, when excited by light of a certain wavelength, induces the production of reactive oxygen species (ROS) that can destroy the microorganism or the target cell (11). In spite of its potential, only a few PAs have been tested against CL in animal models, and only one in humans. Topical application of 5-aminolevulinic acid (ALA) and light in a murine model of CL caused by L. major showed a significant reduction of the parasitic load and the size of lesions (12). Intralesional administration of ALA (one to three PDT sessions) in a patient with CL by L. major produced a 10 to 20% cure, although it is probable that clinical outcome resulted from nonspecific destruction of infected macrophages instead of...

The rational search of novel bioactive molecules against pathogens with immunomodulatory activity is presently one of the most significant approaches to discover and design new therapeutic agents for effective control of infectious diseases, such as the infection caused by Leishmania parasites. In the present study, we evaluated the therapeutic efficacy of the recently characterized immunomodulatory compound 11α,19β-dihydroxy-7-acetoxy-7-deoxoichangin, a seco-limonoid derived from the bark of Raputia heptaphylla (Pittier) using: (1) peritoneal macrophages and (2) Mesocricetus auratus hamsters infected with Leishmania (V.) panamensis and Leishmania (L.) amazonensis. We observed the ability of this seco-limonoid to induce the effective control of the parasite either in vitro [determining an effective concentration 50 (EC50) of 59 µ m at the infection model] and in vivo (inducing clinical improvement or even cure in infected animals treated compared with the groups of animals treated with vehicle solution or meglumine antimoniate).

Traditionally, hamsters are experimentally inoculated in the snout or the footpad. However in these sites an ulcer not always occurs, measurement of lesion size is a hard procedure and animals show difficulty to eat, breathe and move because of the lesion. In order to optimize the hamster model for cutaneous leishmaniasis, young adult male and female golden hamsters (Mesocricetus auratus) were injected intradermally at the dorsal skin with 1 to 1.5 x l0 7 promastigotes of Leishmania species and progression of subsequent lesions were evaluated for up to 16 weeks post infection. The golden hamster was selected because it is considered the adequate bio-model to evaluate drugs against Leishmania as they are susceptible to infection by different species. Cutaneous infection of hamsters results in chronic but controlled lesions, and a clinical evolution with signs similar to those observed in humans. Therefore, the establishment of the extent of infection by measuring the size of the lesion according to the area of indurations and ulcers is feasible. This approach has proven its versatility and easy management during inoculation, follow up and characterization of typical lesions (ulcers), application of treatments through different ways and obtaining of clinical samples after different treatments. By using this method the quality of animal life regarding locomotion, search for food and water, play and social activities is also preserved.