Mitochondrial control region haplotypes of the South American sea lion Otaria flavescens (Shaw, 1800)

The South American sea lion, Otaria flavescens, is widely distributed along the Pacific and Atlantic coasts of South America. However, along the Brazilian coast, there are only two nonbreeding sites for the species (Refúgio de Vida Silvestre da Ilha dos Lobos and Refúgio de Vida Silvestre do Molhe Leste da Barra do Rio Grande), both in Southern Brazil. In this region, the species is continuously under the effect of anthropic activities, mainly those related to environmental contamination with organic and inorganic chemicals and fishery interactions. This paper reports, for the first time, the genetic diversity of O. flavescens found along the Southern Brazilian coast. A 287-bp fragment of the mitochondrial DNA control region (D-loop) was analyzed. Seven novel haplotypes were found in 56 individuals (OFA1-OFA7), with OFA1 being the most frequent (47.54 percent). Nucleotide diversity was moderate (π = 0.62 percent) and haplotype diversity was relatively low (67 percent). Furthermore, the median joining network analysis indicated that Brazilian haplotypes formed a reciprocal monophyletic clade when compared to the haplotypes from the Peruvian population on the Pacific coast. These two populations do not share haplotypes and may have become isolated some time back. Further genetic studies covering the entire species distribution are necessary to better understand the biological implications of the results reported here for the management and conservation of South American sea lions.

Activation of the alternative complement pathway in canine normal serum by Paracoccidioides brasiliensis / Ativação da via alternativa do complemento em soro de cão normal por Paracoccidioides brasiliensis

The dimorphic fungus Paracoccidioides brasiliensis is the etiological agent of paracoccidioidomycosis, a human granulomatous disease. Recently the first case of natural disease in dogs was reported. The complement system is an important effector component of humoral immunity against infectious agents. Therefore, the aim of this study was to evaluate the activation of the dog alternative complement pathway by P. brasiliensis. Initially, the ability of erythrocytes of guinea pig, rabbit, sheep, chicken and swine to activate the dog alternative pathway was evaluated. The guinea pig erythrocytes showed the greatest capacity to activate dog alternative pathway. The alternative (AH50) hemolytic activity was evaluated in 27 serum samples from healthy dogs and the mean values were 87.2 AH50/ml. No significant differences were observed in relation to sex and age. The alternative pathway activation by P. brasiliensis was higher in serum samples from adult dogs when compared to puppies and aged dogs (p < 0.05). This is the first report of dog alternative complement pathway activation by P. brasiliensis and suggests that it may play a protective role in canine paracoccidioidomycosis.

O fungo dimórfico Paracoccidioides brasiliensis é o agente etiológico da paracoccidioidomicose, uma doença granulomatosa humana. Recentemente, foi relatado o primeiro caso da doença natural em cães. O sistema complemento é um importante componente efetor da imunidade humoral contra agentes infecciosos. Portanto, o objetivo deste trabalho foi avaliar a ativação da via alternativa do complemento canina pelo P. brasiliensis. Inicialmente, foi avaliada a capacidade de eritrócitos de cobaia, coelho, carneiro, galinha e suíno ativarem a via alternativa do complemento canino. Os eritrócitos de cobaia apresentaram maior capacidade de ativar a via alternative do complemento canino. A atividade hemolítica da via alternativa (AH50) foi avaliada em 27 amostras de soro de cães saldáveis e os valores médios observados foram de 87,2 AH50/ml. Não foi observada diferença significativa ao sexo e idade. A ativação da via alternativa pelo P. brasiliensis foi maior nas amostras de soro de cães adultos quando comparada aos cães filhotes e idosos (p < 0.05). Este é o primeiro relato da ativação da via alternative do complemento canino pelo fungo P. brasiliensis e sugere que pode ter um papel protetor na paracoccidioidomicose canina.

Antioxidant responses of Laeonereis acuta (Polychaeta) after exposure to hydrogen peroxide

The effects of H2O2 were evaluated in the estuarine worm Laeonereis acuta (Polychaeta, Nereididae) collected at the Patos Lagoon estuary (Southern Brazil) and maintained in the laboratory under controlled salinity (10 psu diluted seawater) and temperature (20°C). The worms were exposed to H2O2 (10 and 50 µM) for 4, 7, and 10 days and the following variables were determined: oxygen consumption, catalase (CAT) and glutathione peroxidase activity in both the supernatant and pellet fractions of whole body homogenates. The concentrations of non-protein sulfhydryl and lipid peroxides (LPO) were also measured. The oxygen consumption response was biphasic, decreasing after 4 days and increasing after 7 and 10 days of exposure to 50 µM H2O2 (P < 0.05). At the same H2O2 concentration, CAT activity was lower (P < 0.05) in the pellet fraction of worms exposed for 10 days compared to control. Non-protein sulfhydryl concentration and glutathione peroxidase activity were not affected by H2O2 exposure. After 10 days, LPO levels were higher (P < 0.05) in worms exposed to 50 µM H2O2 compared to control. The reduction in the antioxidant defense was paralleled by oxidative stress as indicated by higher LPO values (441 percent compared to control). The reduction of CAT activity in the pellet fraction may be related to protein oxidation. These results, taken together with previous findings, suggest that the worms were not able to cope with this H2O2 concentration.

Effects of crustacean hyperglycemic hormones from Carcinus maenas and Orconectes limosus on blood and muscle glucose and glycogen concentration of Chasmagnathus granulata

The effects of purified crustacean hyperglycemic hormones (CHH) from Carcinus maenas or Orconectes limosus, and of eyestalk extract of Chasmagnathus granulata on the blood and muscle glucose and glycogen concentration of Chasmagnathus granulata were investigated. Different groups of animals (at least 7 animals per group) were injected with CHH from either C. maenas or O. limosus CHH dissolved in saline (16 pmol/animal) or crude eyestalk extract of C. granulata (1 eyestalk equivalent/animal). All injections had a volume of 10 microliters. Blood and muscle glucose and glycogen concentrations were determined immediately before the injections and after 30, 60 and 120 min. CHH administration from both species, as well as eyestalk extract, resulted in marked hyperglycemia. However, their effects were different. CHH from C. maenas also caused a decrease in the glycogen concentration of blood (from 89.8 +/- 4.3 to 76.6 +/- 3.1 mg/100 ml) and muscle (from 7.9 +/- 0.8 to 4.0 +/- 0.7 mg/g) and glucose concentration of muscle (from 2.4 +/- 0.3 to 1.2 +/- 0.2 mg/g). CHH from O. limosus caused an increase of glycogen concentration of muscle (from 4.9 +/- 1.1 to 9.0 +/- 1.1 mg/g). The injection of eyestalk extract resulted also in a decrease of hemolymph glycogen (from 157.7 +/- 20.6 to 30.2 +/- 7.7 mg/100 ml). Therefore, C. granulata may have different receptors for CHH in its different tissues, and/or in the same tissue, which act through different metabolic pathways to achieve the same final result, i.e., hyperglycemia