Canibalismo em larvas de matrinxã, Brycon cephalus, após imersão dos ovos à diferentes concentrações de triiodotironina (T3)

The present work evaluated larvae cannibalism of matrinxa, Brycon cephalus, originated from eggs exposed to triiodothyronine, in the period of 36 to 72 hours after hatching. Observed parameters were: weight and length of larvae, stomach content, presence of cannibalism and type of attacks. This study was carried out at Centro de Pesquisa e Gestao de Recursos Pesqueiros Continentais (CEPTA/IBAMA), Pirassununga-SP, in November 2004. Three females were hormonally induced to spawn and pooled oocytes were fertilized and separated into four batches that constituted the treatments: L-1 (control - water); L-2 (0.01 ppm T-3); L-3 (0.05 ppm T-3) and L-4 (0.1 ppm T-3). Eggs were exposed during 15 minutes to water or to solutions containing the different concentrations of T3. Eggs were distributed in 12 conic incubators (60 L), with three replicates per treatment. There was stocked 500 mL of eggs per incubator and hatched larvae were counted. Samples of 30 larvae per treatment were colleted during occurrence of cannibalism (36, 48, 60 and 72 hours post hatching). Predator larvae (with rests of larvae in the stomach) were 50% of the total number of larvae and they presented weight 50% higher compared to that of non predator larvae (without rests of larvae in the stomach) and 9% higher regarding length. Coefficient of variation of weight and length did not differ among treatments, showing similarity in relation to the size. The stomach content revealed that cannibalism occurred in around 50-60 % of larvae, regardless the exposure to the triiodothyronine, and attacks were characterized as head-tail and tail-head attacks.

Variação periódica da triiodotironina (T3) plasmática e sua ação na reprodução induzida do matrinxã, Brycon cephalus (Günther, 1869) em cativeiro

O matrinxã, Brycon cephalus, espécie nativa oriunda da Bacia Amazônica, apresenta características adequadas para a piscicultura. Entretanto, trata-se de peixe reofílico, sendo necessário manejo adequado para induzir à reprodução. O objetivo deste trabalho foi caracterizar o perfil da triiodotironina (T3) plasmática no matrinxã, durante 16 meses (outubro/97 a janeiro/99), relacionando-o com a maturação sexual, além de testar a ação do T3 associado ao extrato pituitário de carpa na reprodução induzida da espécie. O experimento foi conduzido no Centro Nacional de Pesquisa de Peixes Tropicais - CEPTA, Pirassununga, SP, e no Departamento de Morfologia e Fisiologia Animal, da Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal - UNESP. Foram amostrados, mensalmente, 8 a 12 peixes, de ambos os sexos, totalizando 173 animais, de onde retirou-se sangue para dosagem do T3 plasmático. As gônadas foram removidas para análise histológica com identificação do sexo e determinação do estádio de maturação. Analisaram-se testículos e ovários de 161 peixes em corte transversal, tendo predominado machos (63,35%) e o estádio sexual imaturo entre ambos. A concentração plasmática de T3 foi maior de dezembro a janeiro, para machos e fêmeas, coincidindo com o período de maior atividade reprodutiva da espécie e maiores temperaturas da água. em janeiro/99, reprodutores de matrinxã foram induzidos com extrato de pituitária de carpa (EPC) associado à administração de T3 (20 mg/kg em 0,1 mL de suspensão oleosa). Os resultados sugeriram que o T3 atuou sinergicamente à gonadotropina do extrato hipofisário e que o tratamento agudo de triiodotironina com o EPC pode estimular o eixo hipotálamo-hipófise-ovário. O tempo de eclosão das larvas provenientes das fêmeas tratadas com o T3 foi menor e o crescimento inicial e a sobrevivência dessas larvas, maiores.

A comparative solid state C-13 NMR and thermal study of CO2 capture by amidines PMDBD and DBN

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ab initio study and NMR analysis of the complexion of citric acid with ion lithium

Quantum mechanics calculations at the ab initio HF/3-21G* level were carried out with Nuclear Magnetic Resonance (NMR) measurements to characterize citric acid and lithium interactions. The results indicate the formation of a tridentate organometallic compound with one lithium and one citric acid molecule and a tridentate and bidentate compound of two lithium atoms and one citric acid molecule. The results are in agreement with the experimental and theoretical data. (C) 1999 Elsevier B.V. B.V. All rights reserved.

Structural characterization of wild rubbers, microstructure of the rubber extracted from ficus elastica by C-13-NMR

Low molecular weight fractions of polyisoprene extracted from Ficus elastica Herb. ex Hornem. were studied by C-13-NMR. The identification of 2-3 trans terminal units at the end of the polymer chain needed the acquisition of more than 17 000 transients. (C) 2000 Elsevier B.V. Ltd. All rights reserved.

Determinação de Ba, Cd, Cr, Cu, Ni, Pb, Sn e Zn em Tainha (Mugil brasiliensis) nos estuários potiguares

Heavy metals can cause problems of human poisoning by ingestion of contaminated food, and the environment, a negative impact on the aquatic fauna and flora. And for the presence of these metals have been used for aquatic animals biomonitoramento environment. This research was done in order to assess the environmental impact of industrial and domestic sewage dumped in estuaries potiguares, from measures of heavy metals in mullet. The methods used for these determinations are those in the literature for analysis of food and water. Collections were 20 samples of mullet in several municipality of the state of Rio Grande do Norte, from the estuaries potiguares. Were analyzed the content of humidity, ash and heavy metals. The data were subjected to two methods of exploratory analysis: analysis of the main components (PCA), which provided a multivariate interpretation, showing that the samples are grouped according to similarities in the levels of metals and analysis of hierarchical groupings (HCA), producing similar results. These tests have proved useful for the treatment of the data producing information that would hardly viewed directly in the matrix of data. The analysis of the results shows the high levels of metallic species in samples Mugil brasiliensis collected in Estuaries /Potengi, Piranhas/Açu, Guaraíra / Papeba / Arês and Curimataú

Structural analysis of the embryonic development in Brycon cephalus (Gunther, 1869)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Metabolic responses to glucoprivation induced by 2-deoxy-D-glucose in Brycon cephalus (Teleostei, Characidae)

The effects of functional cytoglucopenia provoked by 2-deoxy-D-glucose (2-DG) were studied in adult Brycon cephalus, an omnivorous fish from the Amazon Basin in Brazil. Glycogen content in liver and muscle as well as plasmatic glucose, free fatty acids (FFA), insulin, and glucagon were measured. After 48 h fasting, an intraperitoneal saline injection (NaCl 0.6 g/100 ml) was administered to control fish, whereas the experimental group received 2-DG, dissolved in saline, in the dosage of 80 mg/kg (0.487 mmol/kg) or 150 mg/kg (0.914 mmol/kg) body weight; injection volume was 5 ml in all treatments. Blood and tissue samples were taken immediately before, and 2, 8, 10, and 24 h after administration of the drug or saline. Fish injected with both doses of 2-DG showed a marked increase in glycemia levels. Liver and muscle glycogen decreased after 2-DG administration and reached their lowest values 10-24 h after injection, while in control animals no significant changes were observed. Elevation in plasma glucagon was observed only in response to the maximum dosage of 2-DG administered, especially 10 h and 24 h post-injection. Plasma insulin levels were lower in animals treated with the glucose analogue but only statistically significant 24 h after drug administration. In conclusion, the administration of the non-metabolizable glucose analogue 2-DG in B. cephalus is a stimulus to generate responses towards an increase in the glucose available to tissues, which is a characteristic of a fasting situation. All the above data support the interest of 2-DG administration as a model to study carbohydrate metabolism adjustment mechanisms in fish.

Metabolic changes in Brycon cephalus (Teleostei, Characidae) during post-feeding and fasting

Metabolic changes during the transition from post-feeding to fasting were studied in Brycon cephalus, an omnivorous teleost from the Amazon Basin in Brazil. Body weight and somatic indices (liver and digestive tract), glycogen and glucose content in liver and muscle, as well as plasma glucose, free fatty acids (FFA), insulin and glucagon levels of B. cephalus, were measured at 0, 12, 24, 48, 72, 120, 168 and 336 h after the last feeding. At time 0 h (the moment of food administration, 09.00 h) plasma levels of insulin and glucagon were already high, and relatively high values were maintained until 24 h post-feeding. Glycemia was 6.42 +/- 0.82 mM immediately after food ingestion and 7.53 +/- 1.12 MM at 12 h. Simultaneously, a postprandial replenishment of liver and muscle glycogen reserves was observed. Subsequently, a sharp decrease of plasma insulin occurred, from 7.19 +/- 0.83 ng/ml at 24 h of fasting to 5.27 +/- 0.58 ng/ml at 48 h. This decrease coincided with the drop in liver glucose and liver glycogen, which reached the lowest value at 72 h of fasting (328.56 +/- 192.13 and 70.33 +/- 14.13 mumol/g, respectively). Liver glucose increased after 120 h and reached a peak 168 h post-feeding, which suggests that hepatic gluconeogenesis is occurring. Plasma FFA levels were low after 120 and 168 h and increased again at 336 h of fasting. During the transition from post-feeding to fast condition in B. cephalus, the balance between circulating insulin and glucagon quickly adjust its metabolism to the ingestion or deprivation of food. (C) 2002 Elsevier B.V. All rights reserved.

Genetic monitoring of the Amazonian fish matrincha (Brycon cephalus) using RAPD markers: insights into supportive breeding and conservation programmes

The importance of genetic evaluations in aquaculture programmes has been increased significantly not only to improve effectiveness of hatchery production but also to maintain genetic diversity. In the present study, wild and captive populations of a commercially important neotropical freshwater fish, Brycon cephalus (Amazonian matrincha), were analyzed in order to evaluate the levels of genetic diversity in a breeding programme at a Brazilian research institute of tropical fish. Random Amplified Polymorphic DNA fingerprinting was used to access the genetic variability of a wild stock from the Amazon River and of three captive stocks that correspond to consecutive generations from the fishery culture. Although farmed stocks showed considerably lower genetic variation than the wild population, a significantly higher level of polymorphism was detected in the third hatchery generation. The results seem to reflect a common breeding practice on several hatchery fish programmes that use a small number of parents as broodstocks, obtaining reproductive success with few non-identified mating couples. The obtained data were useful for discussing suitable strategies for the genetic management and biodiversity conservation of this species.

A new species of mullet (Teleostei : Mugilidae) from Venezuela, with a discussion on the taxonomy of Mugil gaimardianus

The original description of Mugil gaimardianus has created various taxonomic problems in the past since the description is ambiguous and the type specimen is apparently lost. The name M. gaimardianus could not be reliably applied to any known species and was suppressed by the International Commission on Zoological Nomenclature (ICZN) (Bulletin of Zoological Nomenclature, 51: 286-287, 1994). Nevertheless, karyological evidence has shown that there is a species of mullet in Venezuelan coastal waters that does not conform to the description of any other mullet from the Western Central Atlantic and has the feature of a red eye that was often used by earlier authors to define nominal M. gaimardianus. The purpose of this study was to make a morphological description of these unusual specimens, provide a morphological diagnosis from other species of Mugil present in the Caribbean and Western Central Atlantic and establish a valid name for the species. (c) 2007 the Authors Journal complication (c) 2007 the Fisheries Society of the British Isles.

Karyotype characterization of Mugil incilis Hancock, 1830 (Mugiliformes: Mugilidae), including a description of an unusual co-localization of major and minor ribosomal genes in the family

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

An old taxonomic dilemma: the identity of the western south Atlantic lebranche mullet (Teleostei: Perciformes: Mugilidae)

The identification of the lebranche mullet in the western south Atlantic has long been problematical. In most recent works either Mugil liza Valenciennes and M. platanus Gunther, 1880 or M. liza and M. cephalus Linnaeus, 1758 were recognized from the region and more rarely the occurrence of only one species has been proposed but without sufficient morphological, biochemical or molecular data to allow the designation of the taxonomically appropriate name. Analysis of meristic and morphometric data taken from samples collected from Venezuela to Argentina, clearly indicates that there is only one species of lebranche mullet in the Caribbean Sea region and the Atlantic coast of South America and that Mugil liza is the appropriate name. The comparison of the combined data from all the samples of M. liza with the data taken from one sample of M. cephalus that originated in the Mediterranean, the possible locality from which type specimens were collected (Eschmeyer and Fricke, 2009), revealed significant differences indicating that they are different species. It is also suggested that individuals from the western north Atlantic identified as M. cephalus might represent a population of M. liza in this region.

NMR and conductivity study of the protonic conductor HPb2Nb3O10 center dot nH(2)O

Electrical conductivity and H-1 Nuclear Magnetic Resonance (NMR) techniques were used to investigate the ion-exchanged layered lead-niobate perovskite HPb2Nb3O10. nH(2)O, over the temperature range 90-350 K. Compounds were synthesized by the sol-gel method and calcinated at 650 degreesC. Analysis of the NMR data gives activation energies for the proton motion in the range 0.14-0.40 eV, which are dependent on the water content. The frequency and temperature dependencies of the proton spin-lattice relaxation times show that the character of the motion of the: water molecules is essentially two-dimensional, reflecting the layered structure of the material. The H-1 line-narrowing transition and the single spin-lattice relaxation rate maximum, observed in the hydrated compounds, are consistent with a Grotthuss-like mechanism for the proton diffusion. (C) 2000 Elsevier B.V. B.V. All rights reserved.

Structural description of humic substances from subtropical coastal environments using elemental analysis, FT-IR and C-13-solid state NMR data

Elemental composition and spectroscopic properties (FT-IR and CP/MAS C-13-NMR) of sedimentary humic substances (HS) from aquatic subtropical environments (a lake, an estuary and two marine sites) are investigated. Humic acids (HA) are relatively richer in nitrogen and in aliphatic chains than fulvic acids (FA) from the same sediments. Conversely, FA are richer in carboxylic groups and in ring polysaccharides than HA. Nitrogen is mostly present as amide groups and for lake and marine HS the FT-IR peaks around 1640 cm(-1) and 1540 cm(-1) identify polypeptides. Estuarine HS exhibit mixed continental-marine influences, these being highly influenced by site location. Overall, the data suggest that aquatic and mixed HS are more aliphatic than has been proposed in current models and also that amide linkages form an important part of their structural configuration.