Differences in rapid eye movement sleep behavior disorder manifestation between synucleinopathies and tauopathies

Rapid eye movement sleep behavior disorder (RBD) frequently occurs in synucleinopathies including multiple system atrophy, Parkinson’s disease, and dementia with Lewy bodies despite the clinical course of RBD being different between these disorders. Comparatively, the existence of RBD symptoms is relatively rare in patients with progressive supranuclear palsy, a tauopathy showing atypical parkinsonism compared with Parkinson’s disease. Moreover, in patients with Alzheimer’s disease, which is another tauopathy, RBD symptoms are less frequent than dementia with Lewy bodies, although both disorders share commonalities in terms of the existence of cortical dementia. Thus, RBD is thought to be relatively specific to synucleinopathies.

     

Effects of hemodynamic edema formation on peripheral vs. central airway mechanics

The mechanisms governing increased central (Rc) and peripheral airway resistance (Rp) during hemodynamic edema formation were studied in anesthetized dogs. Rc and Rp were measured by forced oscillation at 1 Hz by use of a retrograde catheter to partition resistance and a pleural capsule to detect alveolar pressure. After elevation of left atrial pressure to 30 cmH2O by inflation of the left atrial balloon, Rc gradually increased an average of 60% above control in approximately 100 min. Vagotomy had a small influence on the change. On the other hand, Rp with vagus nerves intact increased triphasically: first, it increased transiently by 160% above the control value within 15-20 min before returning to near base line. It then increased gradually for approximately 40 min and finally rose sharply up to five times the control value after approximately 100 min. With vagi cut, the initial phase disappeared, but the second gradual and final rapid phases were not affected. Several sequential mechanisms of increased Rp can be proposed: 1) transient bronchoconstriction mediated by vagal reflex; 2) gradual formation of peribronchial edema; and 3) a sharp increase in airway fluid and formation of bronchial froth. In addition, narrowing of the airways by vascular engorgement may have contributed to the increase of Rp throughout all stages.     

Purification and characterization of an ubiquitin-immuno-reactive protein localized in the cap of young basidiocarp in the basidiomycete Coprinus cinereus.

The ubiquitin-immuno-reactive protein with a molecular weight of 27,800 daltons, which is mainly present in the cap of young basidiocarp, was purified from the basidiomycete Coprinus cinereus. The molecular weight of the native protein was approximately 55,000 as determined by gel filtration chromatography. The isoelectric point of the protein was 4.4. The amino-terminal sequence of the protein was also determined.     

Dynamic mechanism of the self-assembly process of tobacco mosaic virus protein studied by rapid temperature-jump small-angle X-ray scattering using synchrotron radiation

The self-assembly process of tobacco mosaic virus protein (TMVP) was observed by rapid temperature-jump time-resolved solution X-ray small-angle scattering using synchrotron radiation. The temperature-jump device used for the X-ray measurements is rapid enough to cope with even the fastest-assembling process of TMVP, and accumulates data of reasonable signal-to-noise ratios with a minimum total counting time of 7.5 seconds. The measurements suggested that the 20 S disk of TMVP polymerized to stacked disks (short rods). The time to complete stacking varied from approximately 25 seconds to approximately 1200 seconds, depending on the solution condition and magnitude of the temperature gap. Higher protein concentration, ionic strength and temperature favoured faster association. The results were analysed in terms of a set of kinetic equations that describe the two-stage aggregation of TMVP with an equilibrium constant K1, and two rate constants k+2 and k-2 for association and dissociation of disks, respectively. The consistency of the analysis suggests that the TMVP assembly proceeds in two steps of: (1) the aggregation of A-proteins into double-layered disks; and (2) the stacking of double-layered disks. The kinetic analysis indicated that the stacking belongs to the lowest range of protein-protein interaction system.     

Crystal structure determinations of oxidized and reduced pseudoazurins from Achromobacter cycloclastes. Concerted movement of copper site in redox forms with the rearrangement of hydrogen bond at a remote histidine.

The crystal structures of oxidized and reduced pseudoazurins from a denitrifying bacterium, Achromobacter cycloclastes IAM1013, have been determined at 1.35- and 1.6-A resolutions, respectively. The copper site in the oxidized state exhibits a distorted tetrahedral structure like those of other pseudoazurins. However, not only a small change of the copper geometry, but concerted peptide bond flips are identified. The imidazole ring of remote His6 has a hydrogen bonding distance of 2.73 A between N-delta1(His6) and O-gamma1(Thr36) in the oxidized protein. When the protein is reduced at pH 6.0, the imidazole ring rotates by 30.3 degrees and moves 1.00 A away from the position of the oxidized state. A new hydrogen bond between N-epsilon2(His6) and O-epsilon1(Glu4) is formed with a distance of 3.03 A, while the hydrogen bond between N-delta1(His6)-O-gamma1(Thr36) is maintained with an interatomic distance of 2.81 A. A concomitant peptide bond flip of main chain between Ile34 and Thr36 occurs.     

Studies on the population dynamics of the assassin bug,Agriosphodrus dohrni Signoret,in relation to resting site utilization

Population Ecology -     

Effect of DNA on thyroid-hormone binding by specific receptor proteins from rat-liver nuclei

Influence of double-stranded native DNA on the binding of thyroid hormone, 3,5,3'-triiodo-L-thyronine, by the isolated nuclear receptors was studied and the following results were obtained. (1) The receptor-triiodothyronine complexes bound to DNA with moderate affinities. (2) DNA enhanced the hormone binding of the receptors. (3) The stimulatory DNA effect on triiodothyronine binding of the receptors was dependent on DNA concentration, showing its maximum at 30 microgram/ml. (4) The increase in triiodothyronine binding was observed not only in the initial velocity but also in the plateau level which was attained after sufficient incubation time. (5) There were two types of specific receptors in the rat liver nuclear extract. The dissociation constants and the maximal binding capacities for triiodothyronine, which were determined by Scatchard plot analysis in the presence and absence of DNA, suggested that DNA exerted its effect through increasing binding capacity on one class of the receptors and through enhancing affinity for the hormone on the other class of the receptors. (6) Among various polynucleotides examined, the double-stranded eukaryotic DNA was most effective in enhancing the hormone binding by the receptors. These results indicate that the nuclear thyroid hormone receptors interact with double-stranded DNA in a specific manner and are induced to bind more thyroid hormone. We interpret these results as suggesting that a ternary complex of triiodothyronine, the receptor and DNA is formed in the cell nucleus in vivo, probably representing an intrinsic step in the hormone action. Possible physiological significance of this effect of DNA on the receptors is discussed.     

Emission Mössbauer studies of some organocobalamins

Subtle changes in Mössbauer parameters are observed while going from methyl- to ethyl- to adenosylcobalamin, and also when the ‘base’ is detached from the cobalt. The observation of these changes demonstrates that the Co-C bond, among others, remains intact after the Auger event, accompanying the electron-capture decay of the cobalt-57.The differences between ethylcobalamin and the other two organocobalamins in the magnitude of the quadrupole splittings have been interpreted on the basis of the σ-donating tendency of the organic moiety and the CoC bond length. The latter is presumably determined by the steric hindrance offered to the group in approaching the cobalt atom.The ethyl- and adenosylcobalamins in their ‘base-off’ form exhibit a larger quadrupole splitting than the corresponding ‘base-on’ form. In the ‘base-off’ form, the cobalt atom is perhaps raised above the mean plane of the four equatorial nitrogen atoms of the corrin ring, which may result in the diminution of the delocalization of the 3d_π electron density. The higher population of d_π orbitals and the enhanced metallic character of the d_z2, resulting from shrink-age of the CoC bond length, enhances the magnitude of the quadrupole splitting.     

Biosynthesis of a renin binding protein

The biosynthesis of a porcine renin binding protein (RnBP), which specifically binds to renin and forms an inactive high molecular weight renin, was investigated. mRNAs from various porcine tissues were used to investigate in vitro protein synthesis. The kidney mRNA directed the synthesis of a high level of RnBP, whereas the liver, adrenal and pituitary gland mRNAs gave as low but significant level of it. The in vitro synthesized RnBP as well as the immunologically detected RnBP synthesized in vivo had the same molecular weight, 42,000, as that of the purified protein. Moreover, both the human and rat kidney mRNAs directed the synthesis of this protein identified with an anti-porcine RnBP antibody. These results strongly indicate that RnBP, present in various mammalian species, is synthesized in renin-producing tissues as the mature size and undergoes binding with renin without proteolytic processing.