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At least 19 recordsLinked to original sources
PubMed1993

Cholesterol interacts with lactosyl and maltosyl cerebrosides but not with glucosyl or galactosyl cerebrosides in mixed monolayers.

Pure and mixed monolayers of mono- and dihexoside cerebrosides with cholesterol have been characterized at the air/water interface. Cholesterol oxidase was used as a reporter enzyme for the cholesterol-cerebroside interaction in the mixed monolayers. The cerebrosides either were derived from bovine brain extracts or were synthetic. The dihexoside cerebrosides were synthesized by coupling of the hepta-O-acetyl-alpha-lactosyl- or maltosylphosphoramidates with D-erythro-N-acylceramides in dichloromethane, in the presence of trimethylsilyl triflate and molecular sieves, followed by hydrolysis of the acetate-protecting groups. All of the bovine-brain-derived cerebrosides [galactosyl cerebroside (GalCer, types I and II), glucosyl cerebroside (GlcCer), and lactosyl cerebroside (LacCer)] had very condensed force-area isotherms (compressibility values of 3-5 x 10(-3) m/mN at 20 mN/m), as did the synthetic N-stearoylmaltosylceramide (N-18:0 MaltCer). Shorter-chain synthetic cerebrosides (N-8:0 LacCer and N-8:0 MaltCer) had more expanded isotherms, with compressibility values of 15-17 x 10(-3) m/mN. When cholesterol was included in mixed monolayers of monohexoside cerebroside, it did not induce significant condensation of packing (indicating that cholesterol did not increase the order of the acyl chains). However, with dihexoside cerebrosides, a cholesterol-induced condensing effect was observed, which amounted to a 11-19% reduction in the observed mean molecular area. When cholesterol oxidase was used to titrate the stoichiometry of cholesterol/cerebroside in mixed monolayers, at which pure cholesterol clusters appeared, it was observed that in monohexoside cerebroside monolayers cholesterol clusters were present even below a 1:1 molar stoichiometry.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

[Reptile brain cerebrosides and cerebroside sulfates].

Studies have been made on the content of cerebrosides and cerebroside sulfates, as well as on their fatty acid composition in the brain of reptiles, subclass Anapsida (tortoises Emys orbicularis and Testudo horsfieldi) and subclass Lepidosauria (lizards Agama caucasica, A. sanguinolenta, Phrynocephalus mystaceus and snake Natrix tesselata). Total content of cerebrosides and cerebroside sulfates is higher in the brain of Lepidosaurians than in that of Anapsids. In the brain of tortoises, the content of cerebroside fraction with hydroxy fatty acids is significantly higher than of the fraction with normal fatty acids, which is also typical of the brain of homoiothermic mammals and birds. In the brain of Lepidosaurians, concentration of hydroxycerebrosides is considerably lower than of cerebrosides with normal fatty acids, which is similar to lower vertebrates -- amphibians and fishes. Low content of hydroxycerebrosides was found in all the Lepidosaurians investigated, irrespectively of their ecological conditions, being therefore dependent on their phylogenetic position. The composition of fatty acids, both normal and hydroxyderivates, as well as that of glycolipids from the brain of Anapsids and Lepidosaurians is essentially similar. However, some interspecific differences were noted in the pattern of fatty acids of cerebrosides and cerebroside sulfates of the brain, which concern the content of saturated and long chain fatty acids.

Animals↗
PubMedDate not supplied

[Certain physical parameters of cerebroside and phospholipid-cerebroside membranes].

Study of some electric properties of bilayer membranes made of cerebrosides and phospholipid-cerebroside mixture has shown that the capacity of cerebroside film is lower than that of lecithin-cerebroside and phospholipid-cerebroside ones (0.22 +/- 0.01 mkf/cm2 and 0.28 +/- 0.01 mkf/cm2 respectively). The membranes had small cation selectivity. It is stated that conductivity of cations of mixed phospholipid-cerebroside membrane is two orders, and of cerebroside three orders higher than that of phospholipid bilayers. Conductivity of the films under study depends on the medium pH. By means of fluorescent probes cerebrosides were found capable of changing the conformation of phospholipid membranes.

Calcium↗
PubMed1985

[Content of phospholipid, cerebroside and cerebroside sulfate in the central nervous system of mice with acute experimental viral demyelination].

A study was made of the content of phospholipids, cerebrosides and cerebroside sulfates in the central nervous system of mice with experimental acute viral encephalomyelitis. No considerable changes in phospholipid content were revealed. A significant drop in the content of cerebrosides and cerebroside sulfates was defected in the CNS, being more pronounced in the spinal cord of sick animals. The reduction in the content of glycolipids can be explained by myelin disintegration and by the effect of viruses on the olygodendrocytes in which cerebrosides and cerebroside sulfates are synthesized.

Acute Disease↗
PubMed1985

Activator protein required for the enzymatic hydrolysis of cerebroside sulfate. Deficiency in urine of patients affected with cerebroside sulfatase activator deficiency and identity with activators for the enzymatic hydrolysis of GM1 ganglioside and globotriaosylceramide.

Urine specimens from two sibs affected with cerebroside sulfatase activator deficiency were examined to ascertain whether the deficiency of the supplementary activator protein required for the enzymatic hydrolysis of cerebroside sulfate was also evident in urine. Material from chromatographic fractionations was examined for the activator activity to avoid ambiguities resulting from protein inhibition. There were substantial deficits in all chromatographic fractions corresponding to activator-containing fractions of control urines. Since patient urines contained elevated amounts of lactosylceramide, digalactosylceramide, and globotriaosylceramide and since similarities between activators for cerebroside sulfate and GM1 ganglioside hydrolyses had been noted previously, the chromatographic fractions were also examined for activators in other glycosphingolipid hydrolase systems. There was coincidence of activators for the GM1 ganglioside/beta-galactosidase and the globotriaosylceramide/alpha-galactosidase A reactions with the cerebroside sulfatase activator in control urine fractions, and the patients' urines were deficient in activator activities for the three reactions. Identity of the three activators was suggested and antiserum to purified GM1 ganglioside activator was used to test this possibility. There were depressed levels of cross-reacting material in fractions of patient urines by Ouchterlony double diffusion and in unfractionated urine by enzyme-linked immunosorbent assay. Purified activators for the cerebroside sulfate and GM1 ganglioside systems showed lines of identity with no spurring on Ouchterlony double diffusion, identical mobility on immunoelectrophoresis, and similar stimulatory activities toward hydrolysis of the three glycosphingolipid species by their respective enzymes. Finally, the three activator activities were retained by anti-GM1-activator IgG coupled to Sepharose 4B. The results suggest strongly that the same protein entity serves as activator for the enzymatic hydrolysis of cerebroside sulfate, GM1 ganglioside, and globotriaosylceramide.

Animals↗
PubMed1992

The cerebroside sulfate activator from pig kidney: derivitization, cerebroside sulfate binding, and metabolic correction.

Highly purified cerebroside sulfate activator from pig kidneys was characterized by a number of chemical and biological procedures. Methods for chemical modifications were evaluated in an attempt to obtain biologically active derivatives. Iodination, dabsylation, and to a lesser degree reductive methylation provided useful products with good retention of cerebroside sulfate activator activity. Other procedures resulted in largely inactive derivatives or losses in both protein and biological activities. Attempts at renaturation of cerebroside sulfate activator subjected to various denaturing conditions appeared to be successful in many instances, but it was uncertain if the protein structure had actually been disrupted. The binding of cerebroside sulfate by activator was estimated by gel filtration under conditions similar to those of its assay. The formation of a relatively stable 1:1 complex was observed, collaborating results with the human protein. The complex was stable enough to be isolated and shown to be an efficient substrate for arylsulfatase A. The effectiveness of the pig kidney cerebroside sulfate activator for correcting the metabolic defect in activator-deficient human fibroblasts was compared with human materials. The pig kidney protein was taken up more efficiently by the cells and resulted in a better metabolic correction than material from human liver, but was somewhat less effective than a preparation from human urine.

Animals↗
PubMed1975

Comparison of the cerebroside sulphatase and the arylsulphatase activity of human sulphatase A in the absence of activators.

A cerebroside sulphatase (cerebroside-3-sulphate 3 sulphohydrolase, EC 3.1.6.8) assay based on radio thin-layer chromatography is described. The substrate was labelled by the catalytic addition of tritium to cerebroside sulphate. Using this assay the cerebroside sulphatase activity of sulphatase A (Aryl-sulphate sulphohydrolase, EC 3.1.6.1) from human liver and kidney in the absence of activators was investigated. The pH optimum of this reaction depends on the buffer concentration, being pH 4.5 at 50 mM and 5.3 at 10 mM sodium formate. With the latter concentration the apparent Km for cerebroside sulphate is 0.06 mM; SO2-4 and nitrocatechol sulphate inhibit noncompetitively with a Ki of 4.51 mM for Na2SO4 and 0.43 mM for nitrocatechol sulphate. The cerebroside sulphatase activity of sulphatase A is highly dependent on the ionic strength. The optimum sodium formate concentration is 10 mM, and the cerebroside suophatase activity decreases rapidly with increasing buffer concentration. The same concentration dependence is observed in the inhibitory effect of cerebroside sulphate on the arylsulphatase reaction. The inhibition decreases at increasing buffer concentrations, becoming an activation at 70 mM sodium formate. The progress curve of the cerebroside sulphatase reaction shows a deviation from linearity similar to that of the arylsulphatase reaction. Investigation of the effect of preincubation with cerebroside sulphate on the arylsulphatase activity of the enzyme shows that cerebroside sluphatase activity and inactivation of the enzyme by cerebroside sulphate occur simultaneously. These observations are interpreted as supporting the assumption that cerebroside suophate and arylsulphates are degraded at an identical active site on the same enzyme. Differences in the properties of the cerebroside sulphatase and the arylsulphatase reaction of the enzyme may be attributed to the differences in the physiocochemical state of the two substrates.

Binding Sites↗
PubMed1976

Synthesis and turnover of cerebrosides and phosphatidylserine of myelin and microsomal fractions of adult and developing rat brain.

The synthesis and turnover of cerebrosides and phospholipids was followed in microsomal and myelin fractions of developing and adult rat brains after an intracerebral injection of [U-14C]serine. The kinetics of incorporation of radioactivity into microsomal and myelin cerebrosides indicate the possibility of a precursor-product relationship between cerebrosides of these membranes. The specific radioactivity of myelin cerebrosides was corrected for the deposition of newly formed cerebrosides in myelin. Multiphasic curves were obtained for the decline in specific radioactivity of myelin and microsomal cerebrosides, suggesting different cerebroside pools in these membranes. The half-life of the fast turning-over pool of cerebrosides of myelin was 7 and 22 days for the developing and adult rat brain respectively. The half-life of the slowly turning-over pool of myelin cerebrosides was about 145 days for both groups of animals. The half-life of the rapidly turning-over microsomal cerebrosides was calculated to be 20 and 40 h for the developing and adult animals respectively. The half-life of the intermediate and slowly turning-over microsomal cerebrosides was 11 and 60 days respectively, for both groups of animals. The amount of incorporation of radioactivity into microsomal cerebrosides from L-serine was greatly decreased in the adult animals, and greater amounts of the precursor were directed towards the synthesis of phosphatidylserine. In the developing animals, considerable amounts of cerebrosides were synthesized from L-serine, besides phosphatidylserine. The time-course of incorporation indicated that a precursor-product relationship exists between microsomal and myelin phosphatidylserine. The half-life of microsomal phosphatidylserine was calculated to be about 8 h for the fast turning-over pool in both groups of animals.

Animals↗
PubMed1968

Cerebrosides of human aorta: isolation, identification of the hexose, and fatty acid distribution.

Cerebrosides have been isolated from adult human aortic tissue. Each aorta was divided into portions classified as normal, fatty streaks, fibrous plaques, or complicated lesions. The cerebrosides were isolated by Florisil column chromatography, mild alkaline methanolysis, a second Florisil column, and preparative thin-layer chromatography. The concentration of cerebrosides was higher in fatty streaks than in the more advanced plaques; apparently normal tissue gave the same cerebroside content as plaques found in the same aorta. The quantities of cerebrosides ranged from 0.01 to 0.73% of the total lipid. Of the 16 cerebroside samples isolated, 10 contained glucosyl ceramide, 1 contained galactosyl ceramide, and 5 were not analyzed for specific hexose. The fatty acid distribution was determined for 11 of the samples; it was similar to that of spleen cerebrosides. We suggest that aortic cerebrosides originate in the plasma. "Normal tissue" cerebrosides contained less unsaturated fatty acid than cerebrosides from a diseased area of the same aorta. Preparative thin-layer chromatography, the last step of cerebroside isolation, always separated at least two unidentified substances. One of these substances yielded both glucose and galactose on acid hydrolysis. Their removal from the cerebrosides accounts for the lower values for cerebroside compared to other authors' determinations.

Adult↗
PubMed1987

Branched long chain bases in cerebrosides of the guinea pig Harderian gland.

Cerebrosides obtained from the guinea pig Harderian gland were analyzed. The purified cerebrosides gave a single spot on thin-layer chromatography, the Rf value being similar to that of phrenosine obtained from whale brain. The cerebrosides consisted of 74.7% of glucosylceramide and 25.3% of galactosylceramide. The fatty acid composition of these cerebrosides was 0.7% of non-hydroxy fatty acids and 99.3% of alpha-hydroxy fatty acids. Among these alpha-hydroxy fatty acids, a small amount of methyl branched acids was detected. The substituted position of methyl branching of alpha-hydroxy fatty acids was the 16th carbon atom from the carboxyl end irrespective of the carbon chain length. The long chain bases were composed of sphinganine (78%) and sphingenine (22%). 4-D-Hydroxysphinganine was not found. The most remarkable feature of the long chain bases of cerebrosides in the Harderian gland was the presence of a large amount of methyl branched sphinganine. The cerebrosides obtained from the cerebrum and cerebellum of the same animal were also analyzed. The sugar, fatty acid, and long chain base compositions of these cerebrosides were similar to those of whale brain cerebrosides. Methyl branched sphinganine was not found in guinea pig brain.

Animals↗
PubMed1978

On the accessibility and localisation of cerebrosides in central nervous system myelin.

Cerebrosides are concentrated in the myelin sheath where they account for about 20% of the total lipid of the membrane. The present paper is concerned with the role and localisation of these glycolipids in the myelin lamellae. Isolated central nerve myelin preparations have been treated with two probes to investigate cerebroside accessibility in the membrane. The action of galactose oxidase on the galactose headgroups of cerebrosides is followed and quantitated by recovery of the modified glycolipid and resolution of either the 6-aldehydo sugar or galactose remaining by gas-liquid chromatography. With isolated myelin preparations only some 40--50% of the cerebroside galactose is attacked by galactose oxidase at 20 degrees C. With periodate at 20 degrees C over 90% of the galactose headgroups are oxidised in 3 h while the figure is 50--55% over the same time period at 4 degrees C rising to 85% after 22 h. With multilamellar liposomes of mixed myelin lipids only some 20--25% of the available cerebroside is oxidised at 4 degrees C, the reaction being complete in 2 h. The results are discussed in relation to the dispositon of cerebroside in the myelin lamellae. A major location on the external face of the membrane system (intraperiod dense line) is favoured. A role for cerebroside in myelin in terms of increasing the stability and resistance of the lipid phase to ion movement is suggested.

Animals↗