Serum transferrins(Tf)of bottlenose dolphin(Tursiops truncatus)and Yangtze finless porpoise(Neophocaena phocaenoides asiaeorientalis)were analyzed by polyacrylamide gel electrophoresis(PAGE),and the molecular weight of bottlenose dolphin Tf was determined by sodium dodecylsulfate polyacrylamide gel electrophoresis(SDS-PAGE).Bottlenose dolphin Tf and Yangtze finless porpoise Tf appeared to be β-globulins.Both species have five bands even though they belong to different families,which is more bands than previously reported for some fish and terrestrial mammals.The distance between the Tf bands was gradually less from the fastest band to the slowest band.The last two bands were close to each other.However,there were no difference among the two bottlenose dolphins and three finless porpoises.Bottlenose dolphin Tf is composed of two components,whose molecular weight disparity is about 3 000 Da.The Tf molecular weights from two bottlenose dolphins were 72 700 Da/69 900 Da and 73 100 Da/69 700 Da,respectively.These values are obviously lower than those in previous studies of humans,rabbits,rats,Guinea pigs,horses,dogs,mice and cats.
Samples of liver,pancreas,stomach,kidney,intestine,lung,muscle,heart,skin,and brain from two stranded Indo-Pacific humpback dolphins(Sousa chinensis)near Xiamen harbor of China in April 2004 were analyzed for iron(Fe)concentration.The highest levels of Fe were found in the blood(2 471.0 μg/g,dry weight)and liver(2 968.2 μg/g,dry weight)of the animal XM20040429(female,body weight 86 kg,body length1.88 m,estimated age 2-3 year-old)and XM20040430(female,204 kg,2.45 m,4-5 year-old),respectively.In general,Fe concentrations were higher in blood,liver,lung,kidney and muscle than any other organs or tissues in both individuals,although there were obvious differences in body length,body weight and age between these two dolphins.This tissular distribution pattern of Fe concentration of Indo-Pacific humpback dolphins in the present study is similar to those of Dall’s porpoises(Phocoenoides dalli),finless porpoises(Neophocaena phocaenoides)and striped dolphins(Stenella coeruleoalba)in the previous literatures.
Serum transferrin(Tf) is an iron(Fe)-transporting protein with the property of reversibility in binding Fe.Cetaceans are aquatic mammals that exhibit particularly high Fe bioavailability in the body.However,little is known about serum Tf in cetaceans to date.The goal of this study was to determine the special characters of serum Tf between cetacean species and several other vertebrate groups.Zones and types of serum Tf of cetacean bottlenose dolphin(Tursiops truncatus) and rough-toothed dolphin(Steno bredanensis) were studied comparatively,for the first time,with bottom-living yellow catfish(Pelteobagrus fulvidraco),sharptooth catfish(Clarias leather),turbot(Scophthalmus maximus),margined bullhead(Liobagrus marginatus),Chinese sturgeon(Acipenser sinensis),amphibian tiger frog(Rana tigrina),terrestrial mice(Mus musculus) and human(Homo sapiens).Electrophoretic separation of Tf was performed using discontinuous polyacrylamide gel electrophoresis(PAGE).An iron-specific stain method was used to identify the Tf and other Fe-binding proteins.Results suggested that the Tf zones were divided into four areas(Tf I-Tf IV).Serum Tf possessed 4-6 bands in the bottlenose dolphins and 5 Tf bands in the rough-toothed dolphin.These two Tf types in cetacean species were usually more complicated than those of human and other animals studied except for tiger frog.In addition,cetacean serum Tf distributed more widely across the serum Tf zones,and especially all serum Tf I-Tf IV zones in the bottlenose dolphin.The concentrative areas of serum Tf bands and their relative activities seemed to be different between cetaceans and other species,implying an adaptation for special water living habitats and respiratory patterns.Furthermore,although the serum Tf zone patterns among the three bottlenose dolphins were the same,the Tf bands were different from each other,suggesting the tendency of serum polymorphisms in serum Tf of the three bottlenose dolphins.Further research will be required to deepen our understanding not only of the cetacean
