Incubation media affect the survival, pathway and time of embryo development in Neotropical annual fish Austrolebias nigrofasciatus (Rivulidae).

To analyse the survival, pathway and time of embryo development in the annual fish Austrolebias nigrofasciatus eggs were monitored in four liquid media and two damp media under experimental conditions for 130 days until their development was complete. Eggs kept in the same breeding water from oviposition remained in diapause I (DI) during all experiments. In constrast, up to the stage prior to entering diapause II (DII), the other media had no influence on development. Embryos at this stage (DII), however, show longer development time when treated in medium with water and powdered coconut shell so that about 80% of embryos remained in DII at 100 days. In contrast, all other treatments had a significantly lower proportion of embryos remaining in DII. When treated with Yamamoto's solution in humid media, embryos showed the fastest development. The first fully developed embryos (DIII) were seen at 27 days after oviposition. It took an average of 46-58 days for 50% of eggs in each treatment to reach DIII. Compared with other studies, survival in all incubation media was high at between 70 and 98%. Taken together, it can be concluded that all incubation media were found to be viable for maintaining embryos. Altering developmental trajectories through the manipulation of diapauses in different media makes this species a potential model organism for laboratory studies.

Importance of cholinesterase kinetic parameters in environmental monitoring using estuarine fish.

The aim of the present study was to determine the kinetic parameters and cholinesterase (ChE) activity in two teleost fish, the white mouth croaker Micropogonias furnieri (Scianidae) and the Madamango sea catfish Cathorops spixii (Ariidae), to verify their suitability as sentinel species of aquatic pollution by anticholinergic compounds. Individuals of each species were captured in one reference and one polluted site in the Southern Brazilian coast. Brain tissue was used as enzyme source. Inhibition kinetic parameters indicated that ChE from C. spixii collected at the reference site showed more affinity (Ka) for eserine that from those collected at the polluted site. The opposite was observed for the carbamylation constants (Kc). Thus, similar inhibition constants (Ki) were observed. M. furnieri brain showed an extremely low sensitivity to in vitro inhibition by eserine, indicating that it is not a suitable biomarker to be employed in environmental monitoring of anticholinergic compounds. Results from the present study also point to the need for considering kinetic analysis when cholinesterase activity is employed as a biomarker.

Lipid peroxidation induced by Clinostomum detruncatum in muscle of the freshwater fish Rhamdia quelen.

The effect of Clinostomum detruncatum metacercaria infection on the activities of the antioxidant enzymes superoxide dismutase and catalase in muscle of the freshwater fish Rhamdia quelen was analyzed. Tert-butyl hydroperoxide-initiated chemiluminescence, a measure of lipid peroxidation, was also investigated. Enzyme activities were similar in infected and uninfected fishes. However, the chemiluminescence was almost 2-fold higher in muscle of infected fishes than in muscle of uninfected ones. These results indicate that parasite infection induces oxidative stress and a higher level of membrane damage in the fish muscle due to an imbalance between pro-oxidants and non-enzymatic antioxidants. Our results suggest that fish response to parasite infection could involve, as in other vertebrates, reactive oxygen intermediates.

Blood parameters and measurements of weight in the rehabilitation of Magellanic penguins (Spheniscus magellanicus, Foster 1781) / Parâmetros sanguíneos e medidas de peso na reabilitação de pinguins-de-Magalhães (Spheniscus magellanicus, Foster 1781)

During the austral winter the appearance of the Magellanic penguin (Spheniscus magellanicus) is common on the southern coast of Brazil. The oil pollution constitutes a major cause of death of these birds. The monitoring of the weight and blood variables is important to make decisions during the rehabilitation and release of these animals. Thus, the aim of this study was to evaluate the relationship between the penguins' survival during rehabilitation and the values of hematocrit (Hct), total plasma protein (TPP) and body weight (BW) of the birds received at Centro de Recuperação de Animais Marinhos (Recovery Centre for Sea Animals) between 2006 and 2009. The analysis took place weekly, and penguins were classified according to the outcome of the rehabilitation process, when 101 specimens were rehabilitated and released, and 67 died. Released animals showed a decrease in the Hct in the second and third weeks (41±6% and 40±5% respectively) followed by recovery of the values in the fourth and fifth week (41±4% and 43±4% respectively). TPP levels increased steadily over the collections, stabilizing at 7.3±0.8g/dL in the fourth week. On the other hand, animals that died, although following the same response for TPP, showed no significant difference in Hct between collections, and showed a tendency for loss of BW in the last weeks of rehabilitation. The curves of BW and Hct during rehabilitation were considered a potential prognostic indicator of penguins in rehabilitation. Animals that arrived at the recovery centre with BW, Hct and TPP above 2.700g, 45% and 5.6 g / dL, respectively, have a greater chance of recovery, making these parameters crucial points in decision making regarding the treatment to be conducted during rehabilitation.

Durante o inverno austral, é comum o aparecimento do pinguim-de-Magalhães (Spheniscus magellanicus) no litoral sul do Brasil. A poluição por petróleo constitui a maior causa de morte dessas aves. O acompanhamento do peso e de variáveis sanguíneas é importante para a tomada de decisões durante a reabilitação e liberação desses animais. O objetivo deste estudo foi avaliar a relação entre a sobrevivência dos pinguins durante a reabilitação e os valores de hematócrito (Ht), proteínas plasmáticas totais (PPT) e peso corpóreo (PC) das aves recebidas no Centro de Recuperação de Animais Marinhos entre 2006 e 2009. As análises ocorreram semanalmente, e os pinguins foram classificados em função do desfecho do processo de reabilitação, quando 101 espécimes foram reabilitados e liberados e 67 foram a óbito. Animais liberados apresentaram queda no Ht na segunda e terceira semanas (41±6% e 40±5%, respectivamente), seguida de recuperação dos valores na quarta e quinta semanas (41±4% e 43±4%, respectivamente). Os níveis de PPT aumentaram progressivamente ao longo das coletas, estabilizando na quarta semana em 7,3±0,8g/dL. Em contrapartida, animais que foram a óbito, apesar de seguirem a mesma resposta para as PPT, não apresentaram diferença significativa do Ht, entre as coletas, e demonstraram tendência à perda de PC nas últimas semanas de reabilitação. As curvas de PC e Ht foram consideradas indicadoras potenciais de prognóstico durante a reabilitação dos pinguins. Animais que chegaram ao centro de recuperação com PC, Ht e PPT acima de 2.700g, 45% e 5,6g/dL, respectivamente, apresentaram maior chance de recuperação, fazendo desses parâmetros pontos críticos na tomada de decisão quanto ao tratamento a ser conduzido durante a reabilitação.

Clonagem e avaliação da expressão gênica do sbGnRH em machos juvenis e adultos de linguado, Paralichthys orbignyanus / Cloning and evaluation of sbGnRH gene expression in juvenile and adult males of Brazilian flounder Paralichthys orbignyanus

Este estudo buscou clonar o cDNA do sbGnRH, identificar sua expressão em diferentes tecidos do linguado, bem como avaliar possíveis diferenças no RNA mensageiro (RNAm) desse gene no cérebro de linguados machos juvenis e adultos. Por meio da RT-PCR, demonstrou-se pela primeira vez, a clonagem da região codificadora do sbGnRH contendo 297 nucleotídeos do cérebro do linguado. A expressão do sbGnRH foi detectada em vários tecidos periféricos. Foram detectados níveis mais elevados de RNAm do sbGnRH no hipotálamo dos animais adultos. Estes resultados sugerem que o sbGnRH está envolvido na puberdade do linguado.

The objectives of this study were to clone sbGnRH cDNA, evaluate the mRNA levels in different tissues of flounder, and also evaluate brain sbGnRH expression in juvenile and adult males. Using RT-PCR the cloning of a 297 nucleotides coding region of sbGnRH from Brazilian flounder brain was demonstrated for the first time. Expression of sbGnRH was detected in several peripheral tissues. Brain gene expression in the adult flounder was higher than those found in juvenile. These results suggest that sbGnRH is involved on the Brazilian flounder puberty.

Acanthocollaritrema umbilicatum Travassos, Freitas & Bührnheim, 1965 (Digenea: Acanthocollaritrematidae) from the common snook, Centropomus undecimalis, from Itamaracá, state of Pernambuco, Brazil.

Acanthocollaritrema umbilicatum Travassos, Freitas and Bührnheim, 1965, is the only species of Acanthocollaritrematidae described up to the moment. The systematic position of this species and the validity of the family has been questioned by the possible presence of a gonotyl and a genital atrium associated to the acetabulum. In this paper, specimens of this trematode, collected from Centropomus undecimalis cultivated at Itamaracá, State of Pernambuco, northeast Brazil, were studied under optical and scanning electron microscopy, and compared with available sintypes. Gonotyl and genital atrium were not observed and both family and species are considered valid taxonomic entities. A. umbilicatum is redescribed with the addition of new morphological information.

Serum leptin concentration during the terrestrial phase of the Southern elephant seal Mirounga leonina (Carnivora: Phocidae).

This study aimed to verify the serum leptin concentration during the terrestrial phase of the Southern elephant seal (Mirounga leonina) on Elephant Island (South Shetlands, Antarctica). Sera from 25 adult Southern elephant seals were analyzed. Leptin concentration was determined using the 125I radioimmunoassay method. Total protein, triglycerides, and cholesterol concentration were measured by spectrophotometric methods. Seals were grouped by sex and their physiological status (reproducing or molting seals). In reproducing seals, serum concentrations of leptin, total protein, triglycerides, and cholesterol were, respectively, 9.33+/-1.97 ng/ml, 6.87+/-0.09 g/dl, 98.26+/-2.12 mg/dl, and 232.17+/-41.18 mg/dl in males and 5.30+/-1.36 ng/ml, 6.44+/-0.29 g/dl, 109.01+/-3.34 mg/dl, and 219.20+/-26.65 in females (mean+/-1 SD). In molting seals, these values were 2.35+/-1.51 ng/ml, 7.42+/-0.25 mg/dl, 321.10+/-20.01 mg/dl, and 244.66+/-22.24 mg/dl in males and 2.94+/-1.89 ng/ml, 7.88+/-0.46 mg/dl, 197.54 mg/dl, and 224.55+/-16.70 mg/dl in females. In both males and females, there were no significant differences (P>0.05) in total protein and cholesterol concentration between reproducing and molting seals. However, both males and females showed higher leptin concentration (P<0.05) and lower triglyceride concentration (P<0.05) in the reproductive period than in the molt period. In the reproductive period, it was expected that the Southern elephant seal shows an inhibited hunger sensation, mobilizes stored energy, and stimulates the HPG axis. Results from the present study support this hypothesis and suggest that this strategy may be effected by the hormonal stimulation of leptin.