PRESUMPTIVE DYSGERMINOMA IN AN ORANGE-SPOT FRESHWATER STINGRAY (POTAMOTRYGON MOTORO).

A captive-born, 13-yr-old female orange-spot freshwater stingray, (Potamotrygon motoro), presented with an acute caudodorsal swelling. Ultrasonography revealed an intracoelomic mass of mixed echogenicity containing fluid pockets. The ray was euthanatized and gross postmortem examination confirmed the presence of a fluid-filled coelomic mass in the region of the reproductive tract. The mass was identified histologically as a malignant round cell tumor of the ovary. Although immunohistochemistry for protein gene product 9.5 (PGP9.5), octamer-3/4 (OCT-3/4), and inhibin was attempted, antibodies that had been validated in mammalian species did not cross-react with stingray control tissues and did not label neoplastic cells. The final diagnosis was a presumptive dysgerminoma.

Potamotrygon motoro stingray venom induces both neurogenic and inflammatory pain behavior in rodents.

Freshwater stingray accidents cause an immediate, intense, and unrelieved pain which is followed by edema, erythema and necrosis formation. Treatment for stingray envenomation is based on administration of analgesic, antipyretic and anti-inflammatory drugs. Concerning pain control, it is prescribed to immerse punctured limb on hot water to alleviate pain. There are no studies demonstrating specific targets on which stingray venom acts to promote pain. Therefore, the aim of this work was to investigate some mechanisms of Potamotrygon motoro venom (PmV) that contribute to nociception induction. Evaluating spontaneous pain behavior in mice injected i.pl. with PmV, it was seen that PmV induced both neurogenic and inflammatory pain. PmV also induced hyperalgesia in both mice and rats, evaluated through electronic von Frey and rat paw pressure test, respectively. Partial inhibition of hyperalgesia was observed in mice treated with cromolyn or promethazine, which indicated that mast cell and histamine via H1 receptor participate in the inflammatory pain. To search for some targets involved in PmVinduced hyperalgesia, the participation of TRPV1, calcium channels, neurokinins, CGRP, and norepinephrine, was evaluated in rats. It was seen that PmV-induced hyperalgesia occurs with the participation of neurokinins, mainly via NK1 receptor, CGRP, and calcium influx, through both P/Q and L-type voltage-dependent calcium channels, besides TRPV1 activation. The data presented herein indicate that PmV causes hyperalgesia in rodents which is dependent on the participation of several neuroinflammatory mediators.

Complete mitochondrial genome of the ocellate river stingray (Potamotrygon motoro).

We determined the first complete mitochondrial genome sequence of Potamotrygon motoro from South American freshwater stingrays. The total length of P. motoro mitogenome is 17,448 bp, which consists of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes and a control region, with the genome organization and gene order being identical to that of the typical vertebrate. The overall nucleotide composition is 32.3% A, 24.4% T, 30.5% C and 12.8% G. These data will provide useful molecular information for phylogenetic relationships within the family Potamotrygonidae species.

A Severe Accident Caused by an Ocellate River Stingray (Potamotrygon motoro) in Central Brazil: How Well Do We Really Understand Stingray Venom Chemistry, Envenomation, and Therapeutics?

Freshwater stingrays cause many serious human injuries, but identification of the offending species is uncommon. The present case involved a large freshwater stingray, Potamotrygon motoro (Chondrichthyes: Potamotrygonidae), in the Araguaia River in Tocantins, Brazil. Appropriate first aid was administered within ~15 min, except that an ice pack was applied. Analgesics provided no pain relief, although hot compresses did. Ciprofloxacin therapy commenced after ~18 h and continued seven days. Then antibiotic was suspended; however, after two more days and additional tests, cephalosporin therapy was initiated, and proved successful. Pain worsened despite increasingly powerful analgesics, until debridement of the wound was performed after one month. The wound finally closed ~70 days after the accident, but the patient continued to have problems wearing shoes even eight months later. Chemistry and pharmacology of Potamotrygon venom and mucus, and clinical management of freshwater stingray envenomations are reviewed in light of the present case. Bacterial infections of stingray puncture wounds may account for more long-term morbidity than stingray venom. Simultaneous prophylactic use of multiple antibiotics is recommended for all but the most superficial stingray wounds. Distinguishing relative contributions of venom, mucus, and bacteria will require careful genomic and transcriptomic investigations of stingray tissues and contaminating bacteria.

Anti-inflammatory activity of animal oils from the Peruvian Amazon.

ETHNOPHARMACOLOGICAL RELEVANCE: Animal oils and fats from the fishes Electrophorus electricus and Potamotrygon motoro, the reptiles Boa constrictor, Chelonoidis denticulata (Geochelone denticulata) and Melanosuchus niger and the riverine dolphin Inia geoffrensis are used as anti-inflammatory agents in the Peruvian Amazon. The aim of the study was to assess the topic anti-inflammatory effect of the oils/fats as well as to evaluate its antimicrobial activity and fatty acid composition. MATERIALS AND METHODS: The oils/fats were purchased from a traditional store at the Iquitos market of Belen, Peru. The topic anti-inflammatory effect was evaluated by the mice ear edema induced by arachidonic acid (AA) and 12-O-tetradecanoylphorbol-13-acetate (TPA) at the dose of 3mg oil/ear. Indomethacine and nimesulide were used as reference anti-inflammatory drugs. The application resembles the traditional topical use of the oils. The antimicrobial effect of the oils/fats was assessed by the microdilution test against reference strains of Escherichia coli, Staphylococcus aureus and Salmonella enteritidis. The fatty acid composition of the oils/fats (as methyl esters) was determined by GC and GC-MS analysis after saponification. RESULTS: All oils/fats showed topic anti-inflammatory activity, with better effect in the TPA-induced mice ear edema assay. The most active drugs were Potamotrygon motoro, Melanosuchus niger and Geochelone denticulata. In the AA-induced assay, the best activity was found for Potamotrygon motoro and Electrophorus electricus oil. The oil of Electrophorus electricus also showed a weak antimicrobial effect with MIC values of 250 µg/mL against Escherichia coli ATCC 25922 and Salmonella enteritidis-MI. The main fatty acids in the oils were oleic, palmitic and linoleic acids. CONCLUSIONS: Topical application of all the oils/fats investigated showed anti-inflammatory activity in the mice ear edema assay. The effect can be related with the identity and composition of the fatty acids in the samples. This study gives support to the traditional use of animal oils/fats as ant-inflammatory agents in the Peruvian Amazon. However, new alternative should be encouraged due to the conservation status of several of the animal sources of the crude drugs.

Potamotrygon motoro stingray venom induces both neurogenic and inflammatory pain behavior in rodents

Freshwater stingray accidents cause an immediate, intense, and unrelieved pain which is followed by edema, erythema and necrosis formation. Treatment for stingray envenomation is based on administration of analgesic, antipyretic and anti-inflammatory drugs. Concerning pain control, it is prescribed to immerse punctured limb on hot water to alleviate pain. There are no studies demonstrating specific targets on which stingray venom acts to promote pain. Therefore, the aim of this work was to investigate some mechanisms of Potamotrygon motoro venom (PmV) that contribute to nociception induction. Evaluating spontaneous pain behavior in mice injected i.pl. with PmV, it was seen that PmV induced both neurogenic and inflammatory pain. PmV also induced hyperalgesia in both mice and rats, evaluated through electronic von Frey and rat paw pressure test, respectively. Partial inhibition of hyperalgesia was observed in mice treated with cromolyn or promethazine, which indicated that mast cell and histamine via H1 receptor participate in the inflammatory pain. To search for some targets involved in PmVinduced hyperalgesia, the participation of TRPV1, calcium channels, neurokinins, CGRP, and norepinephrine, was evaluated in rats. It was seen that PmV-induced hyperalgesia occurs with the participation of neurokinins, mainly via NK1 receptor, CGRP, and calcium influx, through both P/Q and L-type voltage-dependent calcium channels, besides TRPV1 activation. The data presented herein indicate that PmV causes hyperalgesia in rodents which is dependent on the participation of several neuroinflammatory mediators.

Isolation of a zoonotic pathogen Aeromonas hydrophila from freshwater stingray (Potamotrygon motoro) kept in a Korean aquarium with ricefish (Oryzias latipes)

In the present study, Aeromonas (A.) hydrophila was isolated from a captive-bred adult freshwater stingray (Potamotrygon motoro) reared at a commercial aquarium in Korea. The stingray had bites on its fins, hemorrhages on the ventral part, and congested internal organs. A bacterium was isolated from kidney and subsequently identified as A. hydrophila. Based on phylogenetic analysis results, the isolate in the present study (SNUAh-LA1) was most closely related to A. hydrophila AH10 (China) and A. hydrophila AKR1 (Korea). It is most likely that the pathogen infection resulted from Potamotrygon motoro cohabiting with ricefish (Oryzias latipes).

Relações morfométricas, rendimento e composição centesimal de cortes da carne de arraias capturadas no reservatório de Itaipú / Morphometric relationships, yield and centesimal composition of stingrays meat cauts captured in the Itaipu reservoir / Relaciones morfométricas, rendimento y composición centesimal de cortes de carne de rayas capturadas en el embalse de Itaipu

O presente trabalho foi conduzido com o objetivo de avaliar a morfometria, o rendimento e a composição centesimal de cortes da carne de arraias de água doce capturadas no reservatório de Itaipu. Para os estudos de morfometria e rendimento de cortes foram utilizados 60 animais, distribuídos em delineamento experimental inteiramente casualizado, com três classes de peso corporal (500g, de 501 a 700g e acima de 700g). Houve efeito (p<0,05) do peso em relação ao percentual de resíduos, com maiores índices em animais menores. Para as análises de composição centesimal foram utilizados cortes de filé sem raio (FSR), filé com raio cartilaginoso (FCR) e cauda de 30 animais distribuídos nas mesmas classes de peso já descritas. Foram observados maiores níveis (p<0,05) de matéria mineral no filé com raio para animais entre 501 e 700g. Umidade e matéria mineral apresentaram efeito (p<0,05) entre os diferentes cortes com maiores valores para FSR, FCR, e cauda, respectivamente. Para as demais variáveis avaliadas não houve efeito (p>0,05) entre os tratamentos. Os resultados indicam que o aproveitamento das arraias de água doce pode ser realizado em todas as classes de peso. A composição centesimal associadaao bom rendimento dos cortes da carne revelam a espécie como importante recurso pesqueiro.

This study was conducted to evaluate the morphology, yield and composition of meat cuts from freshwater stingrays caught in the Itaipu Reservoir. For studies of morphometry and cuts yield were used 60 animals, distributed in a completely randomized design with three classes of body weight (500g, 501 to 700g and above 700g). There was effect (P>0,05) of the weight in relation to the percentage of residues, with higher indices in smaller animals. For centesimal composition analyses, were used fillet without rays (FWR), fillet with cartilaginous rays (FWCR) and tail cuts of 30 animals distributed in the same weight classes already described. It was observed highest levels (p <0,05) of ash in the fillet with cartiloginous rays for animals between 501 and 700g. Moisture and ash showed significant effect (p <0,05) between the different cuts, with higher values to FWR, FWCR, and tail respectively. For other variables evaluated there was not effect (p> 0,05) between treatments. The results indicate that freshwater stingrays use can be realized in all weight classes. The centesimal composition associated with the good yield of meat cuts, reveal the species as an important fishery resource.

Se ha realizado esta investigación con el objetivo de evaluar la morfometría, el rendimiento y la composición centesimal en cortes de carne de rayas de agua dulce, capturadas en el embalse de Itaipú. Para los estudios de morfometría y rendimiento de cortes se utilizó 60 animales, distribuidos en un delineamiento completamente aleatorio, con tres clases de peso corporal (500g, 501 a700g y arriba de 700g). Ocurrió efecto (p <0,05) del peso en relación al porcentual de residuos, con mayores índices en animales pequeños. Para los análisis de composición centesimal se utilizó cortes de filete sin radio (FSR), filete con radio cartilaginoso (FCR) y cola de 30 animales distribuidos en las mismas categorías de peso ya descritas. Se observó niveles mayores (p <0,05) de materia mineral en el filete con radio para los animales entre 501 y 700 g. Humedad y materia mineral presentaron efecto (p <0,05) entre los diferentes cortes con mayores valores para FSR, FCR, y la cola, respectivamente. Para las demás variables evaluadas no hubo efecto (p> 0.05) entre los tratamientos. Los resultados indican que el uso de rayas de agua dulce se puede realizar en todas las clases de peso. La composición centesimal, asociada al buen desempeño de los cortes de la carne, revela como la especie es un importante recurso pesquero.

Stirring, charging, and picking: hunting tactics of potamotrygonid rays in the upper Paraná River

Hunting tactics of potamotrygonid freshwater rays remain unreported under natural conditions. Three main foraging tactics of Potamotrygon falkneri and P. motoro are described here based on underwater observations in the upper Paraná River. Both species displayed similar behaviors. The most common tactic was to undulate the disc margins close to, or on, the bottom and thus stirring the substrate and uncovering hidden preys. Another tactic was to charge upon prey concentrated in the shallows. The least common tactic was to pick out prey adhered to the substrate. The first tactic is widespread in several species of marine rays in the Dasyatidae, whereas the remainder (especially picking up prey on substrata above water surface) may be restricted to the Potamotrygonidae.(AU)

As táticas de caça de raias potamotrigonídeas permanecem sem registro sob condições naturais. Três táticas de forrageamento são aqui descritas para Potamotrygon falkneri e P. motoro, com base em observações subaquáticas no curso superior do rio Paraná. Ambas as espécies apresentaram comportamento semelhante. A tática mais comum foi a de ondular as margens do disco próximo ao, ou no, fundo e assim perturbando o substrato e revelando presas abrigadas. Outra tática foi a de investir sobre presas concentradas no raso. A tática menos frequente foi a de apanhar presas aderidas ao substrato. A primeira tática é comum em diversas espécies de raias marinhas da família Dasyatidae, ao passo que as outras duas (em particular apanhar presas em substratos acima da superfície da água) podem estar restritas a Potamotrygonidae.(AU)

Potamotrygon boesemani (Chondrichthyes: Myliobatiformes: Potamotrygonidae), a new species of Neotropical freshwater stingray from Surinam

Potamotrygon boesemani, new species, is described from the Corantijn river drainage in Surinam. The species has a diagnostic dorsal color pattern formed by deep orange to red ocellated spots of irregular form, encircled by relatively broad black rings. Potamotrygon boesemani is distinguished from other ocellated congeners (P. motoro, P. henlei and P. leopoldi) by the more intensely colored ocelli, which are usually yellow in the latter species. From P. motoro it is also distinguished by the darker dorsal background coloration, by the broader black contour of the dorsal ocelli, and by the irregular form of the ocelli as compared to the more rounded shape in the latter species. From P. henlei and P. leopoldi, it is distinguished by the lack of ocelli on tail. From the tentatively identified specimen of P. ocellata, which also has dark orange ocelli, the irregular contour of the ocelli in the new species is also distinctive. The teeth are relatively smaller and in greater number than in P. motoro and P. ocellata, with up to 45 rows in the upper jaw.

Potamotrygon boesemani, espécie nova, é descrita da bacia do rio Corantijn, no Suriname. A espécie apresenta um padrão de coloração dorsal formado por ocelos com coloração alaranjada intensa a vermelha, de formato irregular, margeados por anéis pretos e relativamente grossos. Potamotrygon boesemani distingue-se de outras espécies congêneres oceladas (P. motoro, P. henlei e P. leopoldi) pela coloração mais intensa dos ocelos, que são normalmente amarelados nestas últimas espécies. De P. motoro, distingue-se também pela coloração de fundo mais escura no dorso, pelo contorno preto mais largo nos ocelos dorsais, e pela forma irregular dos ocelos comparada à forma arredondada em P. motoro. De P. henlei e P. leopoldi, distingue-se pela falta de ocelos na cauda. Da espécie tentativamente identificada como P. ocellata, que também possui ocelos laranja escuro, o contorno irregular dos ocelos também é distintivo. Os dentes são relativamente menores e em maior número que em P. motoro. e P. ocellata, com até 45 fileiras na mandíbula superior.