Purification of Mesodermal‐inducing Substances from Carp Swim Bladders I. Extraction and Isoelectric Focusing

Abstract

Mesodermal-inducing substances were isolated from the swim bladders of carp (Carassius auratus). These substances, extracted with 8 M urea, can induce the development of early gastrula ectoderm cells of newts into mesodermal tissues, such as muscles, notochords, mesenchyme, renal tubules, and so on, to a high degree. Isoelectric focusing was used to isolate them as a first purifying step, and five component parts with different pH ranges were obtained. Each part was tested for mesodermal-inducing activity. On the basis of the extent and percentage of the induced tissues, two of them (parts C and D with pH ranges 6.0 to 7.0 and 7.0 to 9.0, respectively) were found to have high inducing activity, and the others had lower activity. The substances present in part C showed only low mesodermal-inducing activity, when diluted with gamma-globulin 100-fold. Apparently highly active mesodermal-inducing substances exist in the two parts C and D.

Identification of a heparin-binding, mesoderm-inducing peptide in the swim-bladder of the red seabream, Pagrus major: a probable fish fibroblast growth factor

“…The carp swim-bladder contains a urea-extractable factor that induces both ventral and dorsal mesoderm, as the same as activin A, and its pI is in the range of 6.0-7.0 (Asashima et al 1987). SBDGF differs from this factor in both pI and mesoderm-inducing ability.…”

Activities of Mesoderm‐Inducing Factors Secreted by Mammalian Cells in Culture1

“…These signals are called mesoderm-inducing factors (MIFs). Although these factors have not yet isolated from the amphibian embryo, MlFs have been extracted from some other tissues, including chicken embryos (3,8,9) and carp swimbladder (4). In 1987, Smith (20) showed that a Xenopus cell line (XTC-cell) secreted a factor (XTC-MIF) that could induce various mesodermal tissues, including muscle and notochord.…”