Diego de Oliveira

Effect of cryoprotectants on the survival of cascudo preto (Rhinelepis aspera) embryos stored at -8 ◦ C

Cryopreservation of germplasm provides a promising method to preserve fish genetic material, which is of great importance in preservation of species diversity, aquaculture, and management of fish models used in biomedical research. In the present study, cryopreservation of Rhinelepis aspera embryos, a Brazilian endangered species, was studied for the first time using a short-term cooling protocol. Embryos at blastoporous closing stage were selected, placed in 6-ml glass vials and stored at -8 °C for 6 h in 10 different cryoprotectant solutions: S1 (17.1% sucrose + 9% methanol); S2 (17.1% sucrose + 9% DMSO); S3 (8.5% sucrose + 8.5% glucose + 9% methanol); S4 (8.5% sucrose + 8.5% glucose + 9% DMSO); S5 (17.1% sucrose + 9% ethylene glycol); S6 (8.5% sucrose + 8.5% glucose + 9% ethylene glycol); S7 (17.1% sucrose + 4.5% methanol + 4.5% DMSO); S8 (17.1% sucrose + 4.5% methanol + 4.5% ethylene glycol); S9 (17.1% sucrose + 4.5% DMSO + 4.5% ethylene glycol); and S10 (100% water). Embryo viability was assessed by hatching rate, counting live larvae and number of failed eggs under a stereomicroscope. The results showed that only the cryoprotectant solutions that contained methanol associated to sucrose (S1, S7 and S8) provided partial protection of Rhinelepis aspera embryos from cold damage (over 50% hatching rate in S1), while the use of DMSO and ethylene glycol, isolated or in combination, resulted in no hatching rate. Further studies are needed in order to extend the storage time and to improve the hatching rate for the species.

Viability of dourado embryos cooled in different cryoprotectant solutions

The objective of this work was to evaluate the effect of different cryoprotectants on the viability of dourado (Salminus brasiliensis) embryos. Ten cryoprotectant solutions were tested. For each solution, 300 embryos were selected at the closing of the blastopore stage, and 300 more embryos were used as a negative control. After cooling (-8oC for 6 hours), the embryos were rehydrated directly in the incubator until hatching. The best result is obtained with the cryoprotectant solution containing 9% methanol associated with 17% sucrose, resulting in a larvae hatching rate of 67.06%.

Corpos hipabissais correlacionados à formação Serra Geral na região do cerro do Coronel, RS : geologia e petrologia

A Formacao Serra Geral e caracterizada por um expressivo volume de derrames basicos de composicao toleitica e pela presenca muito subordinada de vulcanitos acidos. Inumeros corpos intrusivos (soleiras e diques) sao correlacionados com esta unidade e, juntamente com os depositos vulcânicos, constituem a Provincia Magmatica do Parana. Este trabalho trata da investigacao geologica e petrologica das intrusoes basicas/intermediarias da regiao do Cerro do Coronel, a sudeste da cidade de Pantano Grande, RS. Esses corpos hipabissais estao estratigraficamente vinculados a Formacao Serra Geral e formam um alinhamento com orientacao NW-SE. Apresentam contatos concordantes com rochas sedimentares das Formacoes Rio Bonito e Irati. Disjuncoes colunares sao comuns em todas as ocorrencias estudadas e sao afetadas por forte fraturamento NE e NW. A pequena variacao faciologica e caracterizada por termos equigranulares finos a muito finos e, raramente, porfiriticos. Texturalmente, essas rochas apresentam o predominio da textura intergranular e localmente subofitica. Sao constituidos essencialmente por plagioclasio, augita, minerais opacos e, raramente, olivina. Apatita e quartzo ocorrem como minerais acessorios. Mesostase felsica ocorre como etapa final da cristalizacao. Os dados geoquimicos de elementos maiores e elementos-traco permitem classificar as rochas desses corpos hipabissais como andesitos basalticos de afinidade toleitica, cuja evolucao deu-se por mecanismos de cristalizacao fracionada, envolvendo principalmente o fracionamento de plagioclasio e augita. As caracteristicas dos elementos maiores, elementos-traco e elementos terras raras sao compativeis com as apresentadas para magmatismo vinculado a grandes provincias basalticas continentais, como Provincias do Deccan Traps, Parana-Etendeka, Columbia River, Siberian Traps e Karoo. Estas rochas apresentam concentracoes de TiO2 inferiores a 2%, mostrando uma tendencia para o magma-tipo Esmeralda da Provincia Magmatica do Parana.

Sperm quality of the Amazon catfish Leiarius marmoratus (Gill, 1870) after cold storage

This study aimed at assessing the sperm quality of the Amazon catfish, Leiarius marmoratus ¸ after refrigeration without extenders. After capturing the animals and stripping of semen, the following parameters were analyzed: progressive motility, motility quality score, duration of motility and sperm morphology. An aliquot of fresh semen from each male was kept at room temperature (28 ± 2°C) as a control, for further comparison with cooled semen. The semen from each animal was stored in extenders-free individual syringes. The syringes were kept in ice within polystyrene boxes at 13 ± 2°C. For both fresh and cooled semen, seminal parameters were evaluated every one-hour interval, reaching seven hours of analysis. Fresh semen showed a significant decrease in motility, motility quality score and duration of motility remaining viable only for three hours. Progressive motility of the cooled semen displayed a negative linear pattern (P<0.05). The duration of motility increased (P<0.05), reaching its peak after three hours of storage. The motility quality score showed a quadratic pattern. No statistical differences were observed when sperm morphology was assessed (P>0.05), even though the mean values of total abnormalities have increased over the storage time. Further studies focusing on the application of this technique should be performed, including the addition of extenders and cryoprotectants for preservation of the sperm over longer periods.