The neotropical cichlid genus Astronotus currently comprises two valid species: A. ocellatus Agassiz, 1831 and A. crassipinnis Heckel, 1840. The diagnosis is based on color pattern and meristics counts. However, body color pattern is highly variable between regions and the meristic counts show a considerable overlap between populations differing in color patterning. They do not represent true s...

Abstract Marine invertebrates serve as rich sources of secondary metabolites with intriguing chemical diversities and a wide spectrum biological activities. Particularly, marine shell-less sacoglossan mollusks have attracted much attentions due to the fact that apply complex defense agents against their predators. With purpose discovering bioactive develop marine-derived medicines from South Ch...

The molecular mechanisms underlying phenotypic plasticity are not well understood. Identifying mechanisms underlying alternative reproductive tactics (ARTs) in species for which the behavioural and fitness consequences of this variation are well characterized provides an opportunity to integrate evolutionary and mechanistic understanding of the maintenance of variation within populations. In th...

BACKGROUND Snake venom is a potentially lethal and complex mixture of hundreds of functionally diverse proteins that are difficult to purify and hence difficult to characterize. These difficulties have inhibited the development of toxin-targeted therapy, and conventional antivenom is still generated from the sera of horses or sheep immunized with whole venom. Although life-saving, antivenoms co...

Observation of the naturally-occurring accommodative response of a highly visual teleost species provides the opportunity to study its stimulus-response accuracy. A video recording system, linked to a computer digitizing program, was used to measure accommodative changes in lens position in the oscar, Astronotus ocellatus, in response to known food stimuli. The largest lens deviations occurred ...