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Using specific substrates and inhibitors, the presence of acetylcholinesterase (AChE), carboxylesterase (B-esterase) and arylesterase (A-esterase) has been histochemically studied in the developing mouse retina. In the neural retina the perikarya of the Müller cells, ganglion cells and horizontal cells showed high B-esterase activity at the initial stages of their development. In the Müller cells, a second peak of B-esterase activity, coinciding with the time of formation of their lateral processes, was found. AChE first appeared in the ganglion cells at birth and increased thereafter. With the progress of synaptic development, AChE activity in the ganglion cell perikarya was reduced while the enzyme rapidly accumulated in the inner plexiform layer. AChE was also localized in the horizontal cells at the initial stage of their development and completely disappeared thereafter. AChE activity was localized in the outer plexiform layer at the time of weaning. A-esterase was detected in the ganglion cells only and appeared to be lysosomal. In the pigment epithelium only B-esterase was present. The enzyme first appeared in the late prenatal period and rapidly increased after birth. [ABSTRACT FROM AUTHOR]

The action of phenobarbital daily injected has been studied on the rat liver. After 3 injections of 100 mg/kg, the centrolobular hepatocytes exhibit a large proliferation of the smooth endoplasmic reticulum with an important decrease of the glucose-6-phosphatase activity cytochemically detected. The perilobular hepatocytes do not show any modifications of their structure or of their enzymatic activity. These observations demonstrate that in the centrolobular zone, the glucose-6-phosphatase sites became separated from each other by the extension of the new smooth endoplasmic reticulum membranes. [ABSTRACT FROM AUTHOR]

Garlic extract (1 mg dry weight/ml) produced an inhibition of the coagulase reaction and increased the time of coagulation by a factor of 1.5, whereas 4 mg dry weight/ml increased the coagulation time factor by 2.75. At this latter concentration of garlic, coagulation was only partially complete at 4 h. Garlic extract (1.4 mg dry weight/ml) reduced growth in nutrient broth whereas 5.6 mg dry weight/ml was completely inhibitory. These effects were not observed until 8 h after exposure of the organisms to the garlic extracts. There were 5.9% more survivors among garlic treated mice compared to non-treated animals, but this difference is not significant. [ABSTRACT FROM AUTHOR]

Two extracellular cellulases active on carboxymethylcellulose have been isolated from the culture supernatant of Sporocytophaga myxococcoides by a series of gel-filtration and ion-exchange chromatography steps. Cellulase II, being present in highest amount, had a molecular weight determined by gel electrophoresis of 52 000, pI 4.75 and a relatively broad pH optimum (5.5-7.5). Cellulase I had a molecular weight of 46 000. pI was 7.5 and the pH optimum 6.5-7.5. Both cellulases had a very Iow carbohydrate content, possibly present as impurities. They had fairly similar amino acid compositions. The specific activity of cellulase I was about 6 times higher than that of cellulase II. Both cellulases acted as endoglucanases. A cell-associated cellulase, present in amounts corresponding to about 10% of total activity, was partly purified. It showed similarities with cellulase II. [ABSTRACT FROM AUTHOR]

Prolyl hydroxylase was purified from human foetal skin and from a mixture of human foetal tissues by the affinity chromatography procedure using poly(L-proline). The enzyme from both sources was pure, when examined by polyacrylamide gel electrophoresis, as a native protein or in the presence of sodium dodecylsulphate, and enzyme activity recovery varied from 38% to 70% with seven enzyme preparations. The enzyme synthesized from 61.0 µmol to 82.7 µmol hydroxyproline mg protein-1 h-1 at 37 °C with a saturating concentration of (Pro-Pro-Gly)5 as substrate. The molecular weight of the enzyme was identical with that of the chick prolyl hydroxylase when studied by gel filtration, and the molecular weights of the subunits of the enzyme were about 61 000 and 64 000 as determined by sodium dodecylsulphate—polyacrylamide gel electrophoresis. The amino acid composition of the human enzyme was very similar to that of the chick prolyl hydroxylase. Antisera tohuman and chicl prolyl hydroxylases were prepared in rabbits. A single precipitin line was seen between the antiserum to human prolyl hydroxylase and the human enzyme in double immunodiffusion, and no cross-reactivity was detected between the human and chick enzymes by this technique. However, a distinct cross-reactivity was observed between the human and chick enzymes in inhibition experiments. [ABSTRACT FROM AUTHOR]

Closed-circular DNA has been isolated from mitochondrial-enriched fractions from four 'petitenegative' yeasts. Electron microscope analysis has shown in each case the presence of a large discrete size Class of circular DNA greater than 6 μm in length and smaller heterodisperse circular DNA less than 6 μm. Length and molecular weight measurements of the large circular DNA are: Candida parapsilosis, 11.14 ± 0.45 μm and 23.1 x 106; Hansenula wingei, 8.22 ± 0.43 μm and 17.3x 106; Kluyveromyces lactis, 11.44 ± 0.20 μm and 24.0 x 106 and Schizosaccharornyces pombe, 6.04 ± 0. 16 μm and 12.5 x 106. These circular DNAs are thought to be mitochondrial DNA on the basis of their buoyant densities and their enrichment with mitochondria. The finding of a gross size difference between mitochondrial DNA from petite-negative yeasts and Saccharomyces cerevisiae focuses attention on the suggestion that certain unique properties of the latter organism's mitochondrial DNA may be of relevance to the mechanism of the petite mutation in yeast. [ABSTRACT FROM AUTHOR]

The amino-acid composition of a polypeptide fraction that contains a few closely related polypeptides was determined. These polypeptides are obtained in high yield from red kidney beans and stimulate RNA synthesis in a bacterial system and in mouse spleen lymphocytes. Peptide maps of the carboxymethylated fraction were prepared and tryptic peptides purified and analysed for total composition and amino acid sequence. The results revealed that the differences between the polypeptides are due to a few microheterogeneities in the form of amino acid exchanges, but no evidence for the existence of polypeptides of different size or overall structure were obtained. It is concluded that the purification method yields different types of highly similar polypeptides with a molecular weight in the range of 10000, corresponding to about 80 residues, and an unusually high cysteine content of 19 mol/100 mol. These facts show that the present polypeptides are different from all previously analysed factors stimulating RNA synthesis. [ABSTRACT FROM AUTHOR]

A grating monochromator has been used to study the effect of narrow wave-bands (5 nm) at a low energy level between 420 and 800 nm on the biosynthesis of amaranthin in Amarantus tricolor L. var. bicolor ruber Hort. seedlings. Besides a sharp peak in the red with a maximum at 660 nm, a narrow zone of activity in the blue has been detected (max. 440 nm). When seedlings cultivated on different substrates were sequentially exposed either to red (660 nm) and far red or to blue (440 nm) and far red, the second treatment, i.e. far red (730 or 735 nm), annihilated the effect of the first one, without having any influence on the chemical inductive treatments (kinetin or dihydroxy-3,4-phenylalanine). [ABSTRACT FROM AUTHOR]

The mass spectra of the title compounds show peaks corresponding to the primary fragmentation of H, CH3 and (H2 + C2H2). Kinetic study suggests that the molecular ion of 1-phenylcyclobutene and 2-phenyl-1,3-butadiene loses H and CH3 through formation of a common intermediate. This is confirmed by appearance potential and ionisation potential measurements, fragmentation of deuterium labelled compounds and the corrected Z values. [ABSTRACT FROM AUTHOR]