Separation of Endo-1,4-β-xylanases from Geotrichum candidum3C with Various Abilities to Sorb on Insoluble Substrate

Culture liquid from Geotrichum candidum 3C was shown to contain three endoxylanase types: endoxylanase I that binds to cellulose, endoxylanase II that sorbs to insoluble xylan, and endoxylanase III that cannot sorb to insoluble substrate. The catalytic and substrate-binding domains of endoxylanase II were isolated.     

Addressed enzymatic fragmentation of RNA molecules

RNase H has been used for selective cleavage of RNA of MS2 and R17 bacteriophages and 16S RNA from E. coli ribosomes in the region of formation of heteroduplex composed of RNA and an oligodeoxyribonucleotide complementary to a certain part of it. The oligonucleotides used--d(C-T-C-A-T-G-T-T-), d(C-C-A-T-C-T-T-T-T) and d(T-T-T-C-C-A-T-C-T-T-T-T)--were synthesized by chemical methods. The molecular weight of the fragments produced on cleavage of the RNA of MS2 and R17 were estimated with the use of gel electrophoresis under denaturating conditions. The dependence of the enzyme activity on Mg2+ and Na+ concentration and of RNA cleavage on the RNA: oligodeoxyribonucleotide ratio was investigated.     

Osteoblasts during various functional states

At the electron microscopical investigation of osteoblasts in different zones of osteogenesis (enchondral foci, metaphyses, endosteum) in the rat and rabbit femoral bone it has been revealed that their population is heteromorphic. As demonstrate cytochemical data and radioautography, using 3H-uridine, 3H-glycine, 35S-sulfate, 45Ca, results of measurements in osteoblast population, 4 morpho-functional states (or types) are defined. In areas of an intensive osteoplastic process there are young osteoblasts (I type), mature functionally active osteoblasts (II type), osteoblasts with a hypertrophic endoplasmic network (cell-depots of the secrete--III type). In preosteoblasts and osteoblasts of the I type a higher than in osteoblasts of other types intensity of 35S-sulfate incorporation and alkaline phosphatase activity is revealed. In osteoblasts of the II type processes of biosynthesis of collagenous proteins predominate. Osteoblasts of the III type are subjected to destruction during secretion process. In the areas where osteopoesis is dying away, osteoblasts of the I and II types transform into a poorly active state, concerning specific biosynthesis (osteoblasts of the IV type). Presence of osteoblasts having various functional states in the areas of intensive osteopoiesis, depends on certain asynchronity of specific processes of biosyntheses, that occur in them. The morpho-functional states described are regarded as a specific peculiarity in function of collagene-producing cells.     

Structural identity of the multinuclear chondro- and osteoclasts in developing bone

Distributional peculiarities and the ultrastructure of multinuclear elastic cells have been studied in the developed thighbone of rat and rabbit fetuses and new-borns. Multinuclear chondro- and osteoclasts exhibit no noticeable structural specificity with respect to the resorption substrate and are considered to be one and the same type of clastic cells whose main function is to resorb the mineralized tissue.