Culture of chondrocytes in medium supplemented with fetal calf serum or a serum substitute: Ultroser G

Fetal calf serum and a serum substitute, Ultroser G, were compared for their effects on the growth curves, clonal growth and cell cycle progression of rabbit chondrocytes in primary culture and during at least three cell passages and included a screen for the maintenance of cartilage-like differentiation i.e. the presence of type II collagen. Proliferation was also compared with another serum substitute, Nu-Serum. Ultroser G is shown to be equivalent to fetal calf serum as far as chondrocyte proliferation is concerned, clonal growth is improved and biosynthesis of type II collagen is maintained in primary culture.     

Structural basis of the heterogeneity of asparagine-linked oligosaccharides of a Waldenstrom's macroglobulinemia immunoglobulin M

The extent of glycans heterogeneity in a pathological human immunoglobulin M ZAJ has been studied on oligosaccharides released by hydrazinolysis from the purified glycoprotein. After reduction with NaB3H4, asparagine-linked carbohydrate chains were separated by affinity chromatography on concanavalin A-Sepharose into oligomannosidic and N-acetyllactosaminic types. Glycans of the oligomannosidic type were further fractionated by HPLC and those of the N-acetyllactosamine type by preparative high-voltage electrophoresis. The primary structure of the main oligosaccharides was investigated on the basis of micro-methylation analysis, mass spectrometry and sequential exo-glycosidase digestion. Glycans of the oligomannosidic type varied in size from Man5GlcNAc2 to Man9GlcNAc2. N-Acetyllactosaminic glycans were found of the biantennary, bisected-biantennary and triantennary types. They presented a higher degree of heterogeneity due to the presence of a variable number of NeuAc and fucose residues. The new structures we report here were in addition to the major biantennary one we previously described on the basis of methylation analysis and 500 MHz 1H-NMR spectroscopy (Cahour, A., Debeire, P., Hartmann, L., Montreuil, J., Van Halbeek, H. and Vliegenthart, J.F.G. (1984) FEBS Lett. 170, 343-349): NeuAc(alpha 2-6)Gal(beta 1-4)GlcNAc(beta 1-2)Man(alpha 1-3)[Gal(beta 1-4)Glc-NAc(beta 1-2)Man(alpha 1-6)]Man(beta 1-4)]Glc-NAc(beta 1-4) [Fuc(alpha 1-6)]GlcNAc.     

Total and free plasma concentrations of progesterone, cortisol and oestradiol-17 beta during pregnancy, parturition and early lactation in sows

The total (bound plus free) concentrations of progesterone, 20 alpha-dihydroprogesterone, oestradiol-17 beta and cortisol were determined in the plasma of sows at three stages during pregnancy and more intensively from 5 days pre-partum to 5 days post-partum. The free fractions of progesterone, oestradiol-17 beta and cortisol were measured in the same samples by a rate dialysis method. Up to day 110 of gestation, the amounts of free hormone in plasma did not fluctuate independently of their total concentrations. During farrowing, the total and free concentrations of progesterone and cortisol varied independently of each other, whereas total and free oestradiol-17 beta declined simultaneously. The initiation of parturition was associated with a decrease in circulating total progesterone, and was accentuated by a decrease in the free fraction (P less than 0.005) so that its active free concentration was only 20% of its day 1 pre-partum value. Total and free cortisol concentrations rose rapidly during labour so that at 12-18 h after birth of the first piglet 30% of that cortisol in maternal plasma was free hormone.     

Synthesis of RNA I by the RNA polymerase from Micrococcus luteus on the Escherichia coli plasmid pBR322

A mutant strain of Bacillus megaterium, arising spontaneously and resistant to micrococcin , possesses ribosomes which contain an altered form of protein BM-L11 (the homologue of Escherichia coli protein L11). Reconstitution analysis has revealed that the alteration to protein BM-L11 is the sole cause of resistance in this strain.     

Aging of cylinders excised from pulp tissues of the ;golden delicious' apple

Aging cylinders excised from `Golden Delicious' apple (Pyrus malus L.) pulp, like the intact fruit, exhibit some characteristic phenomena such as rise in respiration (climacteric), ethylene synthesis, enzymic changes, and increase in ribosomes and mRNA. Aging of cylinders of pulp tissues may offer a useful physiological tool for the study of maturation and senescence.     

Dislocated type-A spermatogonia in human seminiferous tubules

Summary Type-A spermatogonia can be found in different locations throughout the germinal epithelium of human seminiferous tubules. Generally they represent the population of germ cells adjacent to the basal lamina, but under special conditions they may be located in the adluminal compartment. This aberrant location is found not only in the terminal segments but also in the seminiferous tubules of men older than 65 years of age, and in cases of intratubular seminoma. Furthermore, in both cases, type-A spermatogonia may occupy an intermediate position between basal and intraluminal locations, without showing any signs of cytological damage.Supported by grants from the Deutsche Forschungsgemeinschaft (Ho 388/5-3) and the Alexander von Humboldt-Stiftung     

Purification and characterization of the DNA-dependent RNA polymerase and its subunit sigma from Micrococcus luteus

DNA-dependent RNA polymerase from Micrococcus luteus can be isolated from cell extracts after removal of an excess of nucleic acids by fractionation with ammonium sulfate, followed by two consecutive gel filtrations through agarose and chromatography on cellulose phospate. Either homogeneous holoenzyme or a mixture of core and holoenzyme is obtained in this way, as is indicated by electrophoresis in polyacrylamide gels in the absence of detergent, where core enzyme migrates ahead of holoenzyme. Homogeneous core enzyme can be isolated from holoenzyme by chromatography on DEAE-cellulose. Core enzyme contains the subunits alpha, beta and beta' previously described [U.I. Lill et al., (1975) Eur. J. Biochem. 52, 411-420] in a molar ratio of 2:1:1. Holoenzyme contains an additional subunit sigma of 80 000 molecular weight (molar subunit composition alpha2 betabeta' sigma) and two relatively small polypeptides (molecular weight 14 000 and 25 000, respectively). Subunit sigma may be isolated from holoenzyme by chromatography on DEAE-cellulose at pH 6.9 in the presence of low concentrations of glycerol. The behaviour of holoenzyme during sedimentation in a glycerol gradient at low ionic strength indicates its occurrence as a dimer of the alpha2betabeta'sigma-protomer, whereas the monomeric form is preferred by core enzyme. Holoenzyme is much more active than core enzyme in RNA synthesis on bacteriophage T4DNA as template. The activity of the latter is stimulated by isolated sigma. M. luteus sigma as well as holoenzyme enhances also the activity of core enzyme fro- Escherichia coli. The formation of a hybrid between micrococcal sigma and E. coli core polymerase is also suggested by the influence of sigma on the oligomerisation of the enzyme from E. coli.     

Metabolism of 3-chloro-, 4-chloro-, and 3,5-dichlorobenzoate by a pseudomonad.

Pseudomonas sp. WR912 was isolated by continuous enrichment in three steps with 3-chloro-, 4-chloro-, and finally 3,5-dichlorobenzoate as sole source of carbon and energy. The doubling times of the pure culture with these growth substrates were 2.6, 3.3, and 5.2 h, respectively. Stoichiometric amounts of chloride were eliminated during growth. Oxygen uptake rates with chlorinated benzoates revealed low stereospecificity of the initial benzoate 1,2-dioxygenation. Dihydrodi-hydroxybenzoate dehydrogenase, catechol 1,2-dixoygenase, and muconate cycloisomerase activities were found in cell-free extracts. The ortho cleavage activity for catechols appeared to involve induction of isoenzymes with different stereospecificity towards chlorocatechols. A catabolic pathway for chlorocatechols was proposed on the basis of similarity to chlorophenoxyacetate catabolism, and cometabolism of 3,5-dimethylbenzoate by chlorobenzoate-induced cells yielded 2,5-dihydro-2,4-dimethyl-5-oxo-furan-2-acetic acid.     

The B goes to Z transition of poly(dG-dC) . poly(dG-dC) modified by some platinum derivatives.

Poly(dG-dC) . poly(dG-dC) was modified by chlorodiethylenetriamino platinum (II) chloride, cis-dichlorodiammine platinum (II) and trans-dichlorodiammine platinum (II), respectively. The conformation of these modified poly(dG-dC) . poly(dG-dC) was studied by circular dichroism. In 4 M Na+, the circular dichroism spectra of poly(dG-dC)dien-Pt (0 less than or equal to rb less than or equal to 0.2) are similar (rb is the amount of bound platinum per base). It is concluded that the conformation of these polymers belongs to the Z-family. Dien-Pt complexes stabilize the Z-form. The midpoint of the Z goes to B transition of poly(dG-dC)dien-Pt(0.12) is at 0.2 M NaCl. Moreover another B goes to Z transition is observed at lower salt concentration (midpoint at 6 mM NaCl). In 1 mM phosphate buffer, the stability of Z-poly(dG-dC)dien-Pt(0.12) is greatly affected by the presence of small amounts of EDTA. Poly(dG-dC) . poly(dG-dC) modified by cis-Pt and trans-Pt complexes do not adopt the Z-form even in high salt concentration.