The synthesis of 2,1′-anhydro-,2,1′:3,6-dianhydro-, and 2,1′:3,6: 3′,6′-trianhydro-sucrose

1′-O-Mesyl-6,6′-di-O-tritylsucrose and the corresponding 1′-O-tosyl derivative were prepared from 6,6′-di-O-tritylsucrose by selective sulphonylation. Both sulphonates underwent intramolecular cyclisation reactions, to give 2,1′-anhydrosucrose in high yields rather than the isomeric 1′,4′-anhydride. Sequential benzoylation, detritylation, and mesylation of the 2,1′-anhydride afforded 2,1′-anhydro-6,6′-di-O-mesylsucrose tetrabenzoate which, in the presence of base, gave 2,1′:3,6:3′,6′-trianhydrosucrose that was not identical with the product previously claimed to have this structure. Several derivatives of 2,1′-anhydrosucrose were prepared possessing different functional groups at either the 6,6′- or 4,6′-positions. Dimolar mesitylene-sulphonylation of 3,3′,4′6′-tetra-O-acetylsucrose gave the 6,1′-disulphonate, which, in the presence of alkali, gave 2,1′:3,6-dianhydrosucrose, which was transformed into the 2,1′:3,6:3′,6′-trianhydride by sequential bromination at C-6′ (carbon tetrabromide-triphenylphosphine) and base-catalysed cyclisation. Treatment of 3,3′,4′,6′-tetra-O-benzoylsucrose with sulphuryl chloride furnished the 4,6,1′-trichloro derivative, which, on alkaline hydrolysis, was converted into 2,1′:3,6-dianhydro-4-chloro-4-deoxy-galacto-sucrose.     

A numerical taxonomic study of species of Vibrio isolated from the aquatic environment and birds in Kent, England

A numerical taxonomic study has been carried out to confirm the identity of strains of the family Vibrionaceae isolated during an ecological study. A total of 237 strains were studied including 148 from the aquatic environment, 6 from estuarine birds, 1 from sheep faeces, and 61 control cultures. Duplicates of 21 of the strains were randomly selected and included to estimate test and operator error. Taxonomic resemblance was estimated on the basis of 148 characters using Euclidean distance. The taxonomic position of some strains was reevaluated using the pattern difference coefficient. Strains were clustered by three methods, all of which gave similar results. The estimated average probability of test error was 1.5%. Strains previously identified as Vibrio anguillarum fell into four distinct phenons corresponding to V. anguillarum biovar I, ' V. anguillarum biovar II', V. diazotrophicus , and strains pathogenic to oyster larvae. The latter group characteristically degraded xanthine and probably represents a new species. The phenon corresponding to V. cholerae included the type strain, strains of human origin, and strains isolated in the United Kingdom from birds and the aquatic environment. Some strains of V. cholerae were luminous. Other phenons were identified as V. metschnikovii, V. fluvialis , and Aeromonas spp.     

Comparison of two high-performance liquid chromatographic methods for the determination of oxmetidine and its metabolites in plasma, bile and urine samples

Two high-performance liquid chromatographic methods for the assay of oxmetidine are described: both utilize the same liquid extraction from plasma, urine and bile samples. A normal-phase technique is considered most suitable for the analysis of plasma extracts and a reversed-phase method is preferred for the assay of excretory fluids such as urine and bile which will contain polar metabolites in detectable quantity as well as unchanged oxmetidine.The methods are sensitive enough to follow the kinetic changes in concentration for up to 8 h after the administration of recommended therapeutic doses. Both methods can be automated in respect of the high-performance liquid chromatograph and the samples can be stored for several weeks at −20°C without prejudicing the accuracy of the analysis.     

Thermoregulatory, behavioral and seizure modulatory effects of AVP in the gerbil

Recent reports suggest that arginine vasopressin (AVP) may be an endogenous antipyretic peptide and a mediator of febrile convulsions [10,12]. The spontaneously seizing Mongolian gerbil was used to investigate the thermoregulatory, behavioral and seizure modulatory effects of AVP. Injection of AVP (1.0 and 5.0 μg IV and 0.01–1.0 mg/kg SC) caused dose-related falls in body temperature. Stereotypic scratching, terminated by a body shake, was observed after AVP (1.0–5.0 μg IV). However, such behavior was not observed after subcutaneous injection of AVP. AVP did not potentiate seizure induction in the gerbils but rather reduced the seizure incidence. The data demonstrate that AVP can reduce body temperature and cause specific behaviors, but it does not appear to play a role in the pathogenesis of seizures in the seizure sensitive strain of Mongolian gerbil.     

Lipid selectivity of the calcium and magnesium ion dependent adenosinetriphosphatase, studied with fluorescence quenching by a brominated phospholipid

1,2-Bis(9,10-dibromooleoyl)phosphatidylcholine (BRPC) has been prepared from dioleoylphosphatidylcholine (DOPC). It is shown that the gel to liquid-crystalline phase transition for BRPC occurs below ca. 5 degrees C and that the motional properties of bilayers of BRPC and DOPC as detected by spin-labeled fatty acids are similar. The ATPase activities of the (Ca2+-Mg2+)-ATPase from rabbit muscle sarcoplasmic reticulum reconstituted with BRPC and DOPC are similar. The brominated lipid quenches the fluorescence of the ATPase and can be used to determine selectivity of lipid binding to the ATPase. We show that there is little selectivity on the basis of fatty acyl chain length. Binding constants for phosphatidylcholines and phosphatidylserines are similar in the absence of calcium, although that for phosphatidylserine decreases in the presence of calcium. Phosphatidylethanolamines binds less strongly than phosphatidylcholines, although the difference is small. The largest difference in binding constants is seen between phosphatidylcholines in the gel and liquid-crystalline phases, with a distribution coefficient of 30 in favor of the liquid-crystalline phase. It is shown that the distribution of the ATPase in mixtures of dipalmitoylphosphatidylcholine and BRPC can be understood in terms of the phase diagram for this mixture of lipids. Activities of the ATPase in the presence of mixtures of lipids can be explained in terms of the relative binding constants obtained from the fluorescence experiments.     

High-performance liquid chromatography of long-chain neutral glycosphingolipids and gangliosides

We describe a method for analyzing the perbenzoyl derivatives of both neutral glycosphingolipids and gangliosides with a single high-performance liquid chromatography system. Use of this system, combined with endo- and/or exoglycosidase treatment of glycosphingolipids, provides a sensitive method for obtaining structural information on these compounds. This system has two advantages over previously published chromatography procedures: (i) it uses a commercially available column, and (ii) this single column can be used to analyze gangliosides and their neutral glycosphingolipid products generated by neuraminidase treatment. With this method, we have studied 24 different glycosphingolipids, containing one to ten sugars and one or two sialic acid residues, and have demonstrated its usefulness in evaluating the gangliosides present in human leukocytes.     

Synthesis of steroids in postimplantation mouse embryos cultured in vitro

Steroid and total lipid synthesis have been assessed in postimplantation stage mouse embryos cultured in vitro from the blastocyst to early somite stage. A large increase in acetate incorporation into these compounds is observed during this period. Cholesterol (60–70%), lanosterol (1–15%), and a fraction containing pregnenolone (0–5%) are the major components of the embryo-associated steroid fraction. When embryos are labeled with [³H]pregnenolone, ³H-labeled progesterone, pregnanedione, and a compound identified as acylpregnenolone are produced and secreted into the medium. Production of progesterone and pregnanedione, but not acylpregnenolone, is severely inhibited by the drug cyanoketone (1 μM). Another drug, SU-10603 (10 μM), severely inhibits pregnanedione production, with only a partial repression of progesterone synthesis, and no effect on acylpregnenolone synthesis. Neither drug affects embryonic development. When embryonic tissues were carefully separated and analyzed for their ability to metabolize [³H]pregnenolone it was observed that all tissues (embryo/yolk sac, yolk sac, and trophoblast) can produce progesterone and acylpregnenolone from pregnenolone. Only embryo/yolk sac and yolk sac, but not trophoblast tissue, can produce pregnanedione. The significance of these observations in relation to metabolic communication between the embryo and its mother is discussed.     

Genetic and developmental evidence for a repressed genital primordium in Drosophila melanogaster

Agametic, a maternal-effect mutation, causes the absence of germ cells in approximately 40% of the gonads of flies derived from homozygous females. The nature of the deficiency in the eggs produced by these flies was examined. Ultrastructural abnormalities were seen in the polar granules of some eggs shortly after fertilization. Although a normal number of pole cells form, some are abnormal with degenerating polar granules and nuclear bodies and they contain myeloid bodies. The pole cells reach the gonads and at 14 hr of development all the gonads contain germ cells. However, in 40% of the gonads the germ cells become necrotic and disappear. Thus, the source of agametic gonads in the adult is embryonic death of pole cells in some gonads. To test whether this gonadal death is an autonomous deficiency of the mutant pole cells, mosaic pole cell populations were produced by reciprocal pole cell transplantation. In both types of transplants, the mutant pole cells died autonomously. In eight instances gonads containing only donor pole cells were obtained. Since mutant pole cells die when wild-type pole cells normally begin dividing, we suggest that the lesion affects the ability of these mutant pole cells to reenter the cell cycle.