Cryptic diversity and diversification processes in three cis-Andean Rhamdia species (Siluriformes: Heptapteridae) revealed by DNA barcoding.

The wide distribution of the Neotropical freshwater catfish Rhamdia offers an excellent opportunity to investigate the historical processes responsible for modeling South America's hydrogeological structure. We used sequences from cis-Andean and Mesoamerican Rhamdia species to reconstruct and estimate divergence times among cis-Andean lineages, correlating the results with known geological events. Species delimitation methods based on distance (DNA barcoding and BIN) and coalescence (GMYC) approaches identified nine well-supported lineages from the cis-Andean region from sequences available in the BOLD dataset.

Genetic Variation of the Endangered Neotropical Catfish (Siluriformes: Pimelodidae).

is an important species as a resource for fisheries and aquaculture; it is currently threatened and has a reduced occurrence in South America. The damming of rivers, overfishing, and contamination of freshwater environments are the main impacts on the maintenance of this species. We accessed the genetic diversity and structure of using the DNA barcode and control region (D-loop) sequences of 43 individuals from the Upper Uruguay River Basin (UUR) and 10 sequences from the Upper Paraná River Basin (UPR), which were obtained from GenBank.

Proximate composition and lipid stability of dourado (Salminus brasilensis, Cuvier, 1817) fillets exposed to different levels of ammonia and oxygen in vivo.

Background: The ammonia and oxygen levels of water are physicochemical parameters that affect fish physiology. Thus, we hypothesized that in vivo exposure to stressful ammonia and oxygen levels will affect the post-mortem quality of the fish. Therefore, in this study, the effects of in vivo exposure to stressful ammonia and oxygen levels on the composition and content of thiobarbituric acid reactive substances in fillets from dourado (Salminus brasiliensis) and on the lipid oxidation of these fillets during frozen storage were evaluated.

Genetic characterization of the Neotropical catfish Pimelodus maculatus (Pimelodidae, Siluriformes) in the Upper Uruguay River.

Freshwater fish present unique challenges when one attempts to understand the factors that determine the structure of their populations. Habitat fragmentation is a leading cause of population decline that threatens ecosystems worldwide. In this study, we investigated the conservation status of genetic variability in the Neotropical catfish (Pimelodus maculatus).

Modulation of ERK1/2 and p38(MAPK) by lead in the cerebellum of Brazilian catfish Rhamdia quelen.

Lead (Pb2+) is a neurotoxic trace metal, widespread in aquatic environment that can change physiologic, biochemical and behavioral parameters in diverse fish species. Chemical exposure may drive modulation of mitogen-activated protein kinases (MAPKs) that are a family of highly conserved enzymes which comprise ubiquitous groups of signaling proteins playing critical regulatory roles in cell physiology. Extracellular signal-regulated kinases (ERK1/2) and p38(MAPK) control complex programs such as gene expression, embryogenesis, cell differentiation, cell proliferation, cell death and synaptic plasticity.

Digestive proteinases of Brycon orbignyanus (Characidae, Teleostei): characteristics and effects of protein quality.

Juvenile piracanjuba, Brycon orbignyanus, in the wild consume protein from both plant and animal sources. Digestion of protein in piracanjuba begins in the stomach with pepsin, at low pH, and is followed by hydrolysis at alkaline pH in the lumen of the intestine. The digestive system in piracanjuba was evaluated to characterize the enzymes responsible for the digestion of feed protein and their composition.