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Possibilities of estimation of the structural and functional state of cells by means of morphometrical methods are depicted. On principle, 2 kinds of parameters are used: 1.1. Coefficients of the functional activity of organelles related to cytoplasmic unit volume, 1.2. coefficients of structural preservation of cell organelles. For the authors' research, coefficients of ergastoplasm, free polyribosomes and mitochondria are of special interest. Certainly, the above mentioned principles can be applied to studies on other cell organelles, too, provided that the following rules are considered: 2.1. The organelles should be easily identifyable, 2.2. the interpretation of their function should be generally accepted, 2.3. the structure under consideration should be accessible for morphometrical analysis.

A comparison of the stimulating activity of the muscle cell sap fraction of mice of the 0th, 4th and 6th generations selected according to the protein content in their carcasses in the cell-free ribosomal and polysomal protein synthesis systems showed that both systems are applicable to detect differences in accretion of protein. These differences ar much more distinct in the cell-free polysomal system than in the ribosomal poly(U) system.

A method to prepare polyribosomes from yeasts by using the french-press is described. The highest yield of polyribosomes was derived from late log-phase cells. These polyribosomes, incubated in a cell-free system, were able to reinitiate protein synthesis, which was shown by inhibiting aminoacid incorporation by aurintricarboxylic acid, edeine and sodiumfluoride. We developed the translational system in order to look for the optimal ion-conditions of a DNA-dependent protein-synthesizing system. We found out that at the optimal MgCl2-concentration (6 mM) protein synthesis was strongly inhibited by Mangan ions which are required for transcription in yeast. If protein-synthesis was carried out with 2 mM and 3 mM MgCl2 maximal aminoacid incorporation was observed at 2 mM and 1.5 mM MnCl2.

Inhibition of protein synthesis is one of the few side effects of sulfonylureas and biguanides. Regarding our results obtained with hepatic polyribosomes from diabetic and from control animals, with ribosomes directed by polyuridylic acid as a synthetic messenger, and by centrifugation of the ribosomes through sucrose gradients there is evidence of a direct inhibiting effect of tolbutamide on liver ribosomes. The effect of butyl-biguanide depends on the system used for in vitro protein synthesis. While it is inhibiting protein synthesis of normal liver ribosomes regardless of the attached messenger, it stimulates the incorporation of amino acids by ribosomes from diabetic rats directed by endogenous or by synthetic messengers. The specific pattern of ribosomal distribution in sucrose gradients is unchanged by the administration of tolbutamide to the animal prior to its decapitation. However, butyl-biguanide leads to reduction of the polyribosomal portion of liver ribosomes from normal animals while it is without any furhter effect on the amount of polyribosomes already reduced in diabetes mellitus.

In order to increase the efficiency of different mRNAs from wheat seedlings in carrying out cell-free protein synthesis in the wheat system, efforts were made to remove endogenous mRNA. In this direction, we checked the possibility of using immobilized RNase. Treatment of the cell-free system or its components with this enzyme caused a large decrease in the efficiency of poly tu-directed incorporation of labeled amino acids. This effect did not coincide with an equivalent degradation of RNA, as has been shown by analysis of ribosomes and polysomes. The results are discussed in the light of recent findings of some authors.

Polysomes were isolated both from growing gametophytes of Allomyces arbuscula and from gametangia prepared from mycelia at different periods during gametogenesis. Analysis of polysomes by sucrose gradients showed that ribosomes present in the gametangia monosome pool were shifted into polysomes. This shift was found to be correlated with gametangia differentiation. The ribosome distribution remained virtually unchanged during the early stage of gamete formation. In mature gametes and swarming zygotes a low level of polysomes was detected. Labeling of rRNA by 32PO4 demonstrated a de novo synthesis of monosomes throughout the period of gametangia differentiation. No incorporation of 32PO4 was found to be present in ribosomes prepared from gametangia after onset of gamete formation. On the basis of these labeling experiments it is concluded that radioactivity in polysomes extracted from mature gametes and swarming zygotes can be attributed in part to conserved mRNA. Synchronous formation of gametangia was induced by transferring the vegetative mycelia from growth medium into a low salt buffer. Under these conditions the incorporation of either 32PO4 or 3H-uridine into RNA, particularly into rRNA, was found to be markedly decreased. This obviously indicates a shutdown of RNA synthesis. rRNA from induced mycelia examined by polyacrylamide gel electrophoresis was found to be severely degraded. In contrast to this, rRNA isolated from ribosomes of developing gametangia and from gametes exhibited no degradation products. It is suggested that endonucleases cause rRNA hydrolysis in the hyphal cytoplasm during gametangia differentiation. Ribosomes compartmentalized in gametangia seem to be inaccessible to nucleases during the later process for gametogenesis.