Tiger Barb Research Articles

Expression of genes controlling FDP-aldolase in fish embryos. Thermostability as a genetic marker

A new method of detecting proteins by their thermostability has been proposed to study the genetic control of protein synthesis in early development. The effectiveness of the method was tested on the enzyme aldolase with thermostability defined as the temperature of 50% inactivation upon 30-min of heating ( T 50%). Eggs of a relatively cold water species of the loach, Misgurnus fossilis, were fertilized with sperm of several thermophilic aquarium fish— Brachiodanio rerio, Razbora heteromorpha, Barbus tetrazona, or Carassius auratus. The T 50% of aldolase in the larvae of all hybrid combinations was 1–4°C higher than that in the purebred species of loach larvae. As demonstrated by Misgurnus × Brachiodanio and Misgurnus × Razbora hybrids, the increase in T 50%, caused by the expression of the paternal genes controlling aldolase, begins at the somite stage of development and coincides in time with an increase in the total activity of the enzyme. In the somites the increase in T 50% of aldolase starts earlier and proceeds more rapidly than in the head. In reciprocal hybrids ( Brachiodanio × Misgurnus) a decrease in aldolase thermostability is observed at the same developmental stages.

Diploid-tetraploid relationship among old-world members of the fish family Cyprinidae

Evidence suggesting that the goldfish and the carp of the family Cyprinidae are tetraploid species in relation to other members of the same family were presented. The two barb species, Barbus tetrazona and Barbus jasciatus, were chosen as representatives of diploid members of the family Cyprinidae. These barbs had the diploid chromosome number of 50 and 52 and the DNA value 20–22% that of placental mammals, while the goldfish (Carassius auratus) and the carp (Cyprinus carpio) had the diploid chromosome number of about 104 and the DNA value 50–52% that of placental mammals.