The copolymeric structure of pig skin dermatan sulphate. Isolation and characterization of l-idurono-sulphate-containing oligosaccharides from copolymeric chains

Dermatan sulphate was degraded by testicular hyaluronidase and an oversulphated fraction was isolated by ion-exchange chromatography. This preparation, which contained fairly long segments derived from the non-reducing terminal portion of the molecule, was subjected to periodate oxidation under acidic conditions. The oxidized iduronic acid residues were cleaved by reduction-hydrolysis (Smith-degradation) (Fransson & Carlstedt, 1974) or by alkaline elimination. The oligosaccharides so obtained contained both GlcUA (glucuronic acid) and IdUA-SO(4) (sulphated iduronic acid) residues. Copolymeric oligosaccharides obtained after alkaline elimination were cleaved by chondroitinase-AC into disaccharide and higher oligosaccharides. Since the corresponding oligosaccharides obtained by Smith-degradation were unaffected by this enzyme, it was concluded that the carbohydrate sequences were GalNAc-(IdUA-GalNAc)(n)-GlcUA-GalNAc. The iduronic acid-containing sequences were resistant to digestion with chondroitinase-ABC. It was demonstrated that the presence of unsulphated N-acetylgalactosamine residues in these sequences could be responsible for the observed effect. This information was obtained in an indirect way. Chemically desulphated dermatan sulphate was found to be a poor substrate for the chondroitinase-ABC enzyme. Moreover, digestion with chondroitinase-ABC of chondroitinase-AC-degraded dermatan sulphate released periodate-resistant iduronic acid-containing oligosaccharides. It is concluded that copolymeric sequences of the following structure are present in pig skin dermatan sulphate: [Formula: see text] N-acetylgalactosamine moieties surrounding IdUA-SO(4) residues are unsulphated to a large extent.     

Studies of the genital organs of gilts culled for anoestrus

The genital organs from 54 gilts, slaughtered because of failure to exhibit oestrus, were examined. The mean age of the gilts at slaughter time was 10.8 months. The ovaries of 19 gilts (35.2%) contained no luteal tissue. The ovaries of the other gilts contained luteal tissue as solid corpora lutea only or in combination with cystic corpora lutea and/or luteinized cysts. The average age of the gilts was highest in the latter group and lowest for gilts with ovaries containing only small follicles. Bacteriological and histopathological examinations did not indicate an infectious cause of the condition.     

Preparative thin-layer and column chromatography of prostaglandins

Chromatographic methods are used to identify various monounsaturated PGs (prostaglandins). TLC (thin-layer chromatography) and column chromatography are described in detail. These systems were developed specifically for separating epimers of PGE1 and PGF1, but they are useful in separating some of the known natural PGs as well. A table presents information on identification of the various PGs with neutral silica and acidic silica. The results of these laboratory experiments indicate that 1 ug-1g of PG can be purified by chromatographic methods with little or no loss due to irreversible adsorption or rearrangement if proper precautions and solvent systems are used. TLC seems to be useful in distinguishing diastereomers of PGs. Relative mobilities of the various hydroxy diastereomers are not changed by the solvent systems or by esterification.     

HETEROGENEOUS DISTRIBUTION OF ENZYMES IN SUBMICROSOMAL MEMBRANE FRAGMENTS

Microsomal membranes are postulated to contain either a homogeneous arrangement of individual enzymes or groupings of functionally related enzymes. In the present study we attempt to distinguish between these hypotheses in subfractions of rough microsomes from rat liver. After sonication, the individual vesicles that make up the rough-membrane fraction average less than 1/100 of their previous mass. The vesicles in the sonicated suspension are fractionated roughly according to size on a continuous sucrose gradient. Enzyme activity or concentration in fractions of the gradient is expressed on a phospholipid basis. Fractions containing primarily small vesicles differ from those containing larger vesicles in a manner suggesting a certain degree of separation of NADH-linked from NADPH-linked enzymes. NADH-ferricyanide reductase, NADH-cytochrome c reductase and cytochrome b₅ are most concentrated within the large vesicles in the lowest third of the gradient. In contrast, NADPH-cytochrome c reductase and cytochrome P-450 are found in highest concentration in the small vesicles that make up the upper third of the gradient. The results suggest a nonrandom distribution of these two enzyme groups in the membranes of the endoplasmic reticulum.     

Electron microscopic observations on iron-labelled secondary lysosomes in renal tubules in mice

Summary Labelling of renal tubule cytosomes with electron dense iron granules can be attained by daily intramuscular injections to mice of an iron sorbitol citric-acid compound in a total of approximately 50 mg Fe⁺⁺⁺/100 g of body weight. The labelled cytosomes correspond to secondary lysosomes and represent heterolysosomes or ambilysosomes. The evidence suggests that tubule and lysosome function are undisturbed by the labelling procedure. The use of this method for fine structural studies of the interaction between secondary lysosomes and other cytoplasmic organelles and elements is indicated.Microbodies do not incorporate administered Fe⁺⁺⁺. The morphological observations support the opinion that these bodies are formed in specialized portions of the smooth surfaced endoplasmic reticulum of proximal tubule cells.Supported in part by grants from the Swedish Medical Research Council (Projects No. K 67-12x-1006-2, B 67-12x-1006-02K, K 68-12x-1006-03, and B 69-12x-1006-04A). The assistance of Miss Silwa Mengarelli and Miss Britt-Marie Pettersson is gratefully acknowledged.     

The appearance of monoamines in the adult and developing neurohypophysis of Gallus gallus

Summary Most of the specific monoamine fluorescence of the fowl neurohypophysis is found in the eminentia mediana and the infundibular stem. The densest accumulation of fluorescent structures is located to the zona externa and the subependymal layer, whereas generally only scattered fluorescence is demonstrable in the fiber layer. The neural lobe tissue is provided with very fine smooth fibers often difficult to distinguish. Spectrofluorimetric determinations have shown that noradrenaline is the major catecholamine in the chick neurohypophysis. From the embryological studies it is evident that the monoamine fluorescence first appears in the subependymal layer, the fiber layer and the neural lobe (after about 15 days of incubation). The zona externa fluorescence is not visible until just before hatching. 10 days after hatching the fluorescence intensity of the chick neurohypophysis is similar to that of the adult. Some comparisons are also made with the appearance of monoamines in the mouse.The authors take great pleasure in expressing their warmest thanks for laboratory facilities and good advice provided by Dr. Bengt Falck at the Institute of Histology, Lund, Sweden.This work was supported by grants from the Swedish Natural Science Research Council (project no. 99-35 and 2180-16), from the United States Public Health Service (NB-06701-02) and from the Swedish Medical Research Council (B-69-14 x -56-05 C).     

Application of a Theory for Circumnutations to Geotropic Movements

From a previously published theory (Israelsson and Johnsson 1967) for circumnutations in Helianthus annuus it is possible to predict the geotropical curvatures of the hypocotyls. This extension of the theory is given in the present paper and some geotropical experiments are performed and discussed. The agreement between the theory and the experiments has been verified in the case of gravitational stimulation during relatively short stimulation periods, in the case of continuous gravitational stimulation, etc. Restrictions in the proposed model are discussed.