[Detection of protease-sensitive factors with properties of beta-type transforming growth factor in early loach embryos]. / Obnaruzhenie proteazochuvstvitel'nykh faktorov so svoistvami transformiruiushchego faktora rosta beta-tipa v rannikh zarodyshakh v'iuna.

The blastoderm and yolk of Misgurnus fossilis L. late blastulae were subjected to acid-ethanol extraction and gel filtration on biogel P10 in 1 M CH3COOH. This resulted in isolation of polypeptides that induce substrate-independent proliferation of NIH-3T3 mouse fibroblasts in presence of epidermal growth factor. They did not compete for epidermal growth factor receptors of A-431 cells and inhibited substrate-independent proliferation of human lung carcinoma A-549 cells. These properties of the growth factor-like polypeptides from loach embryos are similar to those of transforming growth factor beta.

[Polypeptide growth factors from the loach embryo at the blastula stage]. / Polipeptidnye faktory rosta zarodyshei v'iuna na stadii blastuly.

Substances which (depending on their dose) stimulate [3H]thymidine incorporation into the trichloracetic acid insoluble fraction of the in vitro cultured mouse NIH-3T3 cells were isolated from the blastoderm and from the yolk of the teleost fish loach embryos (8-9 hours after the eggs' fertilization) by the acid-ethanol extraction method. In the medium which contained the 0.5% fetal calf serum with addition of 100 micrograms/ml of the above mentioned substances the stimulation of labeled thymidine incorporation into cellular DNA achieved 44-56% of the level which was detected in the presence of 10% serum. The pepsin and trypsin treatment led to a significant decrease in the mitogenic activity of the both investigated factors, that confirmed their polypeptide structure. The factors are sufficiently thermostable as they retain almost completely the activity after 30 min heating at 56 degrees C and lose less than 70% of their activity after boiling for 5 min. Gel-filtration of the growth factors from the loach embryos' yolk on the Biogel P-60 column has shown that the growth stimulating activity is mainly concentrated in the fraction which contains the polypeptides with molecular weight about 5 kDa. The significance of mitogenic factors in the loach embryos at the earliest stages of the embryonic development is discussed.