Identification of Ca2+-Activated Neutral Protease in the Peripheral Nerve and Its Effects on Neurofilament Degeneration

Rat sciatic nerve segments were incubated in five different media. Disappearance of neurofilament (NF) triplet proteins (200K, 160K, and 68K MW) occurred in medium containing Ca²⁺ and was inhibited by the addition of E-64-c or leupeptin. Therefore, the presence in the peripheral nerve of an enzyme whose properties are similar to those of Ca²⁺-activated neutral protease (CANP) is suggested. The extraction of crude CANP from rat sciatic nerve was performed. CANP activity was completely recovered (0.129 ± 0.008 U/g) in the precipitate salted out by the addition of 0 to 50% saturated ammonium sulfate to the soluble fraction of the peripheral nerve (crude CANP). Properties of the crude CANP were examined using NF as a substrate and were found to be similar to those of the CANP extracted from skeletal muscle. Identification of the crude CANP with the CANP extracted from rat skeletal muscle was performed using the immunoreplica method. Bands corresponding to 73K were detected in both CANPs.     

Aktivität der Myofibrillen- und Sarkosomen-Adenosintriphosphatasen im Flügelmuskel der Bienenarbeiterinnen

Zusammenfassung In bezug auf unsere frühere Arbeit über die Beziehung zwischen ATPase-Aktivität des Flügelmuskels und dem Alter nach Ausschlüpfen der Bienenarbeiterinnen wurde die Aktivität der zwei im Flügelmuskel vorhandenen ATPasen, Myofibrillen-(M) und Sarkosomen-(S-)ATPasen gesondert untersucht. Die Wirkung von Ca- und Mg-Ionen sowie einiger Hemmungsmittel wurde für beide ATPasen geprüft. Die Aktivität der S-ATPase nimmt während der ersten Woche nach Ausschlüpfen graduell zu. Demgegenüber zeigt die Aktivität der M-ATPase den maximalen Wert beim Ausschlüpfen und danach ein etwas niedriges konstantes Niveau bis zum 10. Tag. Im Zusammenhang mit dem Ergebnis wurden auch einige biochemische Erörterungen gegeben.Biologisch-biochemische Studien über den Flügelmuskel der Honigbiene. Mitteilung II. [Mitteilung I siehe in Z. vergl. Physiol. 39, 21 (1956).]     

Glutamate dehydrogenase deficiency in spinocerebellar degenerations

Glutamate dehydrogenase (GDH) activity in leukocytes and platelets in spinocerebellar degenerations (SCD) was determined. In the same subject, GDH activity was higher and more reproducible in platelets than in leukocytes. GDH was decreased significantly in olivopontocerebellar atrophy (OPCA) (Ca. 30% decrease). Pyruvate dehydrogenase (PDH) in platelets showed non specific decreased activity in SCD and amyotropic lateral sclerosis. Energy metabolism in cerebellum may be diminished in some types of ataxia, and glutaminergic neurons may be more affected in OPCA than in other SCD.     

Sodium counterion activity of poly(S-carboxymethyl-L-cysteine) and the beta–random-coil transition

Sodium ion activity was measured using a Na-glass electrode in a solution of poly(S-carboxymethyl-L -cysteine) with no added salt at various degrees of neutralization and various concentrations for samples of different molecular weights. The conformational change from random coil to the β-structure was detected from the activity coefficient of counterions, as well as from CD. At a constant degree of neutralization, the activity coefficient is insensitive to a concentration change not only in the random-coil state, but also in the range of conformational change if the concentration is below about 3 × 10^?2 monomolal. At high concentrations of about 5 × 10^?2 monomolal, however, the activity coefficient becomes low, probably due to the occurrence of the stacking of the pleated sheets.     

Short-term nicotine exposure induces long-lasting modulation of gustatory plasticity in Caenorhabditis elegans

Nicotine administration induces many effects on animal behavior. In wild-type Caenorhabditis elegans, gustatory plasticity results in reduced chemotaxis toward NaCl of otherwise attractive concentrations after pre-exposure to 100 mM NaCl in the absence of food. However, acute nicotine administration during a 15 min pre-exposure period inhibits gustatory plasticity, whereas chronic nicotine administration during worm development facilitates the plasticity. To investigate the relationship between the duration of nicotine administration and its effects, we exposed worms to nicotine for various periods during development. The modulatory effect of nicotine on gustatory plasticity was gradually switched from inhibition to facilitation with increased duration of nicotine administration. Moreover, inhibition of plasticity was sustained after relatively short-term chronic administration, with effects lasting for 45 h after the removal of nicotine. Similar to the acute inhibitory effect after 15 min nicotine pre-exposure, the inhibitory effect after short-term chronic administration was dependent on the nicotinic acetylcholine receptor subunit genes lev-1 and unc-29, and genes involved in serotonin biosynthesis bas-1 and tph-1. The impaired inhibition in bas-1 and tph-1mutants was recovered by exogenous serotonin, demonstrating that serotonin plays an important role in the long-lasting inhibitory effects of short-term chronic nicotine exposure.     

A new method for the determination of optical purity of synthetic peptides

A novel and very accurate method was established for the determination of the optical purity of a peptide by use of the following procedure: (1) hydrolysis of the peptide in deuterium chloride, (2) gas chromatographic separation of each amino acid enantiomer on a chiral phase, and (3) determination of the D /L ratio by mass fragmentography. In this manner, one can estimate the true chiral purity of each amino acid residue with an accuracy of ～0.2%. The recemization effected during hydrolysis could be eliminated in principle, since the artificially formed DL -amino acids are necessarily labeled at the α-position with deuterium and can thus be distinguished mass spectrometrically from the D - and L -isomer originally present in the peptide. The versatility of the method was proven by analysis of model peptides, as well as by a racemization test in fragment condensation.     

Phase separation in the beta-coil transition of poly-S-carboxyethyl-L-cysteine

The visible phase separation encountered in aqeuous system involving the β-coil transition is investigated on poly-S-carboxyethyl-L -cysteine at a constant ionic strength of 0.2 molal. Solubility of the polymer decreases as the average charge density or pH is decreased, indicating that short-range interactions favor the phase separation. The titration curve of the gel phase (i.e., of the pure β-structure) is obtained by using the solubility data. Circular dichroism of the solution phase in equilibrium with the gel shows that the β-structure is present in the solution phase. To isolate the two phases, centrifugal force is applied and it is demonstrated that the polymers in the two phases are in true equilibrium with each other. The effect of total concentration on the solubility of polymer and the degree of neutralization in each phase is interpreted in terms of the poly-dispersity of the sample.     

Living Monoplacophora: morphological conservatism or recent diversification?

Kano, Y., Kimura, S., Kimura, T. & Warén, A. (2012) Living Monoplacophora: morphological conservatism or recent diversification? —Zoologica Scripta, 41, 471–488. The molluscs of the class Monoplacophora are classic and probably the most striking case of a ‘living fossil’ in the deep sea. Until the discovery of the first living specimens in 1950s, the group was thought to be extinct since the Devonian period, almost 400 million years ago. Morphological conservatism over a long span of time in a ‘living‐fossil’ lineage may theoretically result in distant but closely resembling taxa, and this idea apparently led some authors to recognise as many as six families and three superfamilies for less than three dozen living monoplacophoran species. However, no genetic or fossil data have been available regarding the history of their diversification. Here we describe Veleropilina seisuimaruae sp. n., the first member of the class from the north‐western Pacific, based on the shell, radular and anatomical characteristics. Phylogenetic analyses of 6‐kb DNA sequences estimate that the divergence of V. seisuimaruae and Laevipilina hyalina, the only other monoplacophoran available for genetic studies, dates back only to the Late Cretaceous, despite their significant morphological differences among the living members of the class. The recent Monoplacophora might have radiated fairly recently from a cryptic lineage with ordinary rates of morphological evolution, possibly after the global deep‐sea anoxia at the Cenomanian/Turonian boundary.