Vegetalizing factor

Kada, T., K. Morita, and T. Inoue. Anti-mutagenic action of vegetable factor(s) on the mutagenic principle of tryptophan pyrolysate. Mutat Res 1978 53 351-353. 

WC is the climate factor and represents the amount of erosive wind energy present at a particular (county-level) location W L is a function of wind direction, field length, and width and is the unsheltered median travel distance of wind across a field and WV is the vegetative factor. The relationship between E and the other variables is highly nonlinear. 

Fig. 2. Mesodermal and endodermal tissues induced by the highly purified vegetalizing factor in isolated gastrula ectoderm of Triturm alpestries (sandwich method) (courtesy of Dr. H. Grunz). Abbreviations End, endoderm M, muscle and N, notochord.

In chick and amphibian embryos the factors are preferentially found in the microsomal fraction (40,000 g sediment). The vegetalizing factor can, in part, be detached from the membranes by treatment with deoxy-cholate (Tiedemann et al., 1962). In monosomes and polysomes of 11-day chick embryos only a very small inducing activity is found (Knochel, 1972a). 

In chick embryos the vegetalizing factor is also present in the 100,000... 

In older (9-11-day) chick embryos the neuralizing factor is found in almost all organs, whereas little vegetalizing factor is foimd in brain from which the meninges were removed and also in the retina (Tiede-mann, 1963). 

B. Mechanism of Action of the Vegetalizing Factor at the Molecular Level... 

Calf thymus DNA, Xenopus liver DNA, and also DNA from T4 coli phage inhibit the vegetalizing factor. Heteropolymeric [poly d( A-T), poly d(G-C), poly d(I-C)] and homopolymeric (poly I-poly C, poly dA poly dT) double-stranded polynucleotides have no inhibitory activity (Table I). Melted, single-stranded chick DNA has about the same inhibitory effect as double-stranded DNA. However, it is not excluded that a partial renaturation occurs under the conditions of the test. Also, DNA, which was partially degraded by sonication, has about the same inhibitory effect as untreated DNA. 

The Effects of Vabious Types of Macromoeechles on the Inducing Potency of the Crude and the Highly Purified Vegetalizing Factor... 

This amount corresponds to the inhibitor isolated from 3 gm of fresh tissue (trunk of chick embryo) 700 fig of DNA corresponds to the amount DNA obtained from about 3 gm of tissue. Inhibition of the vegetalizing factor is observed only in the presence of the inhibitor fraction from chick embryos or DNA, not in the presence of polyanions such as tRNA, double-stranded homo- and heteropolymeres of nucleotides or polysaccharides. The neuralizing activity of the crude protein is not inhibited by DNA (not shown in the table). 

Whether the sequences of single-stranded DNA and of RNA which combine with vegetalizing factor are homologous is not yet known. 

It has been shown that the type of neural structures induced by the neuralizing factor depends on secondary interactions. The neuralizing factor alone induces foreheads. Mixtures of neuralizing and vegetalizing factors induce hindbrain with ear vesicles or neural tube, depending on the ratio in which the two factors are applied (Toivonen and Saxen, 1955 Saxen and Toivonen, 1961 Tiedemann and Tiedemann, 1964). The modification of the induction response is probably not exerted by the vegetalizing factor itself but by the mesoderm which is induced along with the neural tissue (Toivonen and Saxen, 1968). 

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