Fish egg polysialoglycoproteins: circular dichroism and proton nuclear magnetic resonance studies of novel oligosaccharide units containing one sialidase-resistant N-glycolylneuraminic acid residue in each molecule

Long-core units having the common sequence Ga1NAc beta 1 leads to 4(NeuGc2 leads to 3)Ga1NAc beta 1 leads to 3Gal beta 1 leads to 4Ga1 beta 1 leads to 3Ga1NAc are one of the major constituents of rainbow trout egg polysialoglycoproteins. The existing ambiguity regarding the anomeric configuration of the sialidase-resistant unsubstituted sialyl group present in this novel type of oligosaccharide chains has been resolved by a circular dichroism difference spectral method. The fact that the negative band originating from the carbohydrate n leads to pi transition for this sialyl group was observed offers conclusive proof of the alpha-anomeric configuration. Next particularly interesting is the fact that the chemical shifts of the sialidase-resistant sialyl H-3eq and H-3ax protons were respectively found at relatively higher and lower magnetic field than for the corresponding protons of other sialyl groups. A consideration of molecular models shows that the observed anomalies are all in the directions compatible with expectations on the basis of the magnetic anisotropy effect due to the carboxylate group and steric compression effects by van der Walls interactions between groups that are sterically compressed. In addition to the observed resistance to bacterial sialidases of this sialyl group, it did not behave even as a competitive inhibitor of the sialidase, Arthrobacter ureafaciens, indicating that inaccessibility of this unique sialyl group toward the enzyme. Finally, the analysis of the proton nuclear magnetic resonances of sialidase-sensitive mono- and oligosialyl groups present in the long-core units was based on comparisons of diagnostically important regions in the spectra of homologous oligosaccharides of N-glycolylneuraminic acid.     

Dielectric analysis of mitochondria isolated from rat liver I. Swollen mitoplasts as simulated by a single-shell model

A re-evaluation of the dielectric studies on isolated mitochondria (Pauly, H., Packer L., and Schwan, H.P. (1960) J. Biophys. Biochem. Cytol. 7, 589–601, and ibid. 7, 603–612) is presented. The suspensions of ‘mitoplasts’ prepared from rat liver mitochondria by a hyposmotic (10 mM KCI) treatment showed a dielectric dispersion with its characteristic frequency lying in the 1–100 MHz range. In the analysis of data special emphasis was put on the choice of the theoretical models to employ after serutiny of their applicability to the suspensions tested. As such we adopted the theory of Hanai et al. (Hanai, T., Asami, K., and Koizumi, N. (1979) Bull. Inst. Chem. Res., Kyoto Univ. 57, 297–305) that was advanced to include concentrated suspensions of shelled spheres. Curve fittings based on that theory resulted in a better agreement with experiment than the fittings based on a conventional theory for dilute suspensions. Major findings from our analyses on the swollen mitoplasts are that: (i) the limiting membrane of the mitoplasts has a specific electrical capacity of 1 μF/cm², (ii) the ratio of permittivity (or dielectric constant) for the mitoplast interior and permittivity for the external medium is 0.6–0.7, and (iii) the conductivity ratio between the interior phase and the medium is approx. 0.6. Reasons for discrepancy between the results of Pauly et al. and ours are discussed.     

Isolation and structures of glycoprotein-derived free sialooligosaccharides from the unfertilized eggs of Tribolodon hakonensis, a dace. Intracellular accumulation of a novel class of biantennary disialooligosaccharides

Novel acidic oligosaccharides were isolated in abnormally large amounts (about 200 ng/egg) from the unfertilized eggs of Tribolodon hakonensis (a dace, "ugui" in Japanese). The free oligosaccharides were found to consist of a mixture of disialylated species most of which end with beta-mannosyl N-acetylglucosamine structure at their reducing termini, i.e. greater than Man beta 1-4GlcNAc. A minute portion of the sialooligosaccharides was found to have the reducing terminal structure, di-N-acetylchitobiose, i.e. greater than Man beta 1-4GlcNAc beta 1-4GlcNAc. From the structural analysis of these free sialooligosaccharides, the following structures are proposed: (sequence; see text) Occurrence of such a symmetrically or dissymmetrically branched form of the biantennary nonreducing periphery as revealed here is novel. Although it is unknown why and how such high amounts of free oligosaccharides are accumulated in unfertilized eggs, these were presumably protein-linked components and must be released at certain stages of oogenesis.     

Changes in osmotic water permeability of the eel gills during seawater and freshwater adaptation

Summary Changes in osmotic water permeability of the isolated gills of the Japanese eel,Anguilla japonica were studied during transfer to seawater or to fresh water. The water permeability increased gradually during the course of seawater transfer and attained a maximal level after 2 weeks. The water permeability of the freshwater eel gills was reduced when calcium ions were added to the incubation medium at a concentration of 1 mM, where-as no effect of the ion was observed on the gills of the seawater-adapted eel even at a higher concentration (10 mM). In contrast to seawater transfer, the water permeability decreased to a low level almost immediately (3 h) after transfer from seawater to fresh water. The acute reduction of the water permeability was also seen in the gills of the hypophysectomized eel after transfer to fresh water.The gradual increase in the gill water permeability during seawater transfer is correlated with an increase in the number of chloride cells. In scanning electron microscopy, chloride cells of seawater-adapted eel gills exhibit a pit-like structure, which was larger than in the freshwater eel. On transfer from seawater to fresh water, the pit diameter became smaller within 6 h. Hypophysectomy did not affect the change in gill surface structures during transfer to fresh water. The junctions between the chloride cells of seawater eel gills are reported to be of the leaky type. The parallel change in osmotic water permeability and in pit size of the chloride cells during seawater or freshwater transfer or after hypophysectomy suggests that these cells could provide a major route of water as well as ion movement.This paper is a portion of a thesis presented to Hokkaido University by t. Ogasawara in partial fulfilment of the requirements for Doctor of Fisheries     

Pectic polysaccharides in carrot cells growing in suspension culture

Pectic polysaccharides in the cell wall of suspension-cultured carrot cells (Daucus carota L.) were fractionated into high- and low-molecular-weight components by molecular-sieve chromatography with a Sepharose 4B column. During the phase of cell-wall expansion, the relative content of low-molecular-weight polymers rapidly increased. Electrophoretic analyses of these fractions showed that the high-molecular-weight components were largely composed of neutral and weakly acidic polymers while the low-molecular-weight fraction contained, in addition to neutral polymers, strongly acidic polyuronides in which the content of neutral sugars was very small. The accumulation of a large amount of the strongly acidic polyuronides occurred in a late stage of cell-wall growth, concomitant with a marked decrease in the high-molecular-weight components.Abbreviation MW molecular weight     

Quantification of two variant strains contained in freeze-dried Japanese BCG vaccine preparation by real-time PCR.

Japanese bacillus Calmette-Guerin (BCG) vaccine preparation contains two types of variant strains, Type I, which has a 22-base-pair deletion in the RD16 region, and Type II, which has an identical sequence to those of other BCG strains. In this study, we established a method to quantify the percentage of variant strain Type II contained in freeze-dried BCG product with real-time PCR. With this method we examined the master seed lot Tokyo 172, two secondary seed lots, Tokyo 172-1 and Tokyo 172-2, which were produced from Tokyo 172, and four commercial lots produced form Tokyo 172-1. Tokyo 172, Tokyo 172-1, and Tokyo 172-2 contained 55.1%, 19.5%, and 3.6% of Type II variant strain, respectively. Commercial lots contained 1.5%, 4.5%, 7.4%, and 4.3% of Type II variant strain, respectively. These results indicated that the two variant strains contained in the master seed lot continued to coexist in subsequently produced lots with a decrease in population of variant strain Type II. This method would be useful for quality control of commercial Japanese BCG vaccine preparations.     

Time-resolved chemiluminescence study of the TiO2 photocatalytic reaction and its induced active oxygen species.

The time-resolved chemiluminescence (CL) method has been applied to study the TiO(2) photocatalytic reaction on a micros-ms timescale. The experimental set-up for time-resolved CL was improved for confirmation of the unique luminol CL induced by the photocatalytic reaction. The third harmonic light (355 nm) from an Nd:YAG laser was used for the light source of the TiO(2) photocatalytic reaction. Luminol CL induced by this reaction was detected by a photomultiplier tube (PMT) and a preamplifier was used for amplifying the CL signal. Experimental conditions affecting the photocatalytically induced CL were discussed in detail. The involvement of active oxygen species such as .OH, O(2) (.-) and H(2)O(2) in the CL was examined by adding their scavengers. It is concluded that .OH was greatly involved in the CL on a micros-ms timescale, especially in time periods <100 micros after illumination of the pulse laser. On the other hand, CL generated by O(2) (.-) began to increase after 100 micros and became dominant after 2.5 ms. A small part of the CL might be generated by H(2)O(2) on the whole micros-ms timescale. A CL reaction mechanism related with .OH and dissolved oxygen was proposed to explain the photocatalytically induced luminol CL on a micros-ms timescale, especially in periods <100 micros.     

Isolation and Characterization of Two Importin-r{beta} Genes from Rice

The nuclear transport of proteins is mediated by the complexof importin-a and importing. We isolated two cDNAs encodingimporting-rß from rice. A rice importin-rßwas demonstrated to interact with rice GST-importin-a fusionproteins. The presence of two importin-rß genes wasshown for the first time among a variety of eukaryotes. (Received March 30, 1998; Accepted May 13, 1998)