FETAL DEVELOPMENT: THE EFFECTS OF MATURATION ON IN VITRO PROTEIN SYNTHESIS BY MOUSE BRAIN TISSUE

—The elucidation of the translational regulatory events which function during the critical fetal and neonatal period is an important prerequisite to our understanding of normal, as well as abnormal, brain growth and differentiation. Brain cell suspensions and cell-free homogenates were employed to study the protein synthetic activity during the maturation of fetal- neural tissue. The results clearly demonstrated that while neural tissue from 1-day postnatal mice was 10 times more active in protein synthesis than brain tissue from adult mice, the former was many fold less active in translational events than fetal neural tissue from 13-day post-zygotic mice. Fetal polypeptide synthetic activity was found to decrease from the 13th day to the 19th day post-zygotic. This decrement in the translational activity was not due to amino acid availability or pools, or to differences, quantitatively or qualitatively, in polysome concentrations. The enhanced rate of protein synthetic activity measured with neural tissue from 13-day post-zygotic mice was shown to be due to an increase in rate of protein synthesis and not to an enhanced rate of protein degradation.     

Characteristics of the range of mutations in nystatin resistance induced in yeasts by 6-N-hydroxylaminopurine

A simple procedure for induction of nistatin-resistant mutants in yeasts under the action of 6-N-hydroxylaminopurine (HAP) is proposed. Some differences between the spectra of mutations induced by HAP and UV-light are observed: HAP induces dominant and double recessive mutants more frequently.     

New matrices for the purification of pectinases by affinity chromatography

Polygalacturonic acid was used as a ligand in the affinity technique for pectinases purification from the filtrate of Aspergillus niger 71 culture. For this purpose four matrices were examined, namely, alkylamine controlled porous glass (CPG), alkylamine silica gel as well as keratin or polyamide coated silica gel. Good results of pectinase purification was obtained on silanized CPG or keratin coated silica gel supports.     

Adaptation of the activity of membrane carbohydrases of chick small intestine to various carbohydrates

Adaptation changes in membrane carbohydrases and those localized in the apical glycocalyx of enterocytes have been studied in chicks under the impact of carbohydrates. The investigated enzymes were not equally adapted to the carbohydrates of various degrees of polymerization. The response character of membrane carbohydrases depends on proximo-distal localization of enzymes in the small intestine and it is not specific to carbohydrates.     

Cytology of tracheobronchial amyloidosis

Localized amyloidosis of the respiratory tract is seldom diagnosed in cytologic specimens. This report describes a case of the tracheobronchial form of amyloidosis in which diagnostic material was present in a cytologic specimen obtained during bronchoscopy.     

Humoral antibodies to the antigens related to the structural protein antigens of the mammary cancer virus (MTV) in breast cancer patients and in healthy donors

Indirect radioimmunoassay and immunoperoxidase studies provided further evidence of human serum reactivity with murine mammary tumor virus (MMTV) structural proteins. Examination of over 400 human sera from breast cancer (BC) patients and controls has shown that the incidence of antibodies which react with MMTV structural proteins was significantly higher in BC patients (50%) than in patients with carcinomas of other organs (3%) or normal women (3%). However, the percentage of subjects immune to MMTV was higher in pregnant women (10%) as compared with normal subjects. All the women with BC of the first clinical stage had antibodies to MMTV. The percentage of immune donors was lower among patients with BC of the later stages (IIa, 90%, IIb, 76%, III, 27%, IV, 0%). Thus, a good agreement has been demonstrated between the first stages of BC and expression of antibodies to MMTV.