A Method of Determination of Penta-, Tetra-, Tri-, and Disaccharides from Xylan by Ion-exchange Chromatography

Bacillus subtilis B7, a tmrA mutant, shows both tunicamycin resistance and a-amylase hyperproductivity. The tmrA characters can be transferred simultaneously to recipient cells by DNA-mediated transformation. We found a typical gene amplification phenomenon in the tmrA transformants and B7 strain. The amplified unit, 16.3kb in size, covers a-amylase structural gene amyE to another tunicamycin resistance gene tmrB, which is located 9kb downstream of the amyE gene. About 10 repeating units are supposed to be tandemly repeated in the transformants. Amplification of the wild amyE and tmrB genes could be the cause of the α-amylase hyperproductivity and tunicamycin resistance of the tmrA transformants and B7 strain.     

Both Neurons and Astrocytes Exhibited Tetrodotoxin-Resistant Metabotropic Glutamate Receptor-Dependent Spontaneous Slow Ca2+ Oscillations in Striatum

The striatum plays an important role in linking cortical activity to basal ganglia outputs. Group I metabotropic glutamate receptors (mGluRs) are densely expressed in the medium spiny projection neurons and may be a therapeutic target for Parkinson''s disease. The group I mGluRs are known to modulate the intracellular Ca²⁺ signaling. To characterize Ca²⁺ signaling in striatal cells, spontaneous cytoplasmic Ca²⁺ transients were examined in acute slice preparations from transgenic mice expressing green fluorescent protein (GFP) in the astrocytes. In both the GFP-negative cells (putative-neurons) and astrocytes of the striatum, spontaneous slow and long-lasting intracellular Ca²⁺ transients (referred to as slow Ca²⁺ oscillations), which lasted up to approximately 200 s, were found. Neither the inhibition of action potentials nor ionotropic glutamate receptors blocked the slow Ca²⁺ oscillation. Depletion of the intracellular Ca²⁺ store and the blockade of inositol 1,4,5-trisphosphate receptors greatly reduced the transient rate of the slow Ca²⁺ oscillation, and the application of an antagonist against mGluR5 also blocked the slow Ca²⁺ oscillation in both putative-neurons and astrocytes. Thus, the mGluR5-inositol 1,4,5-trisphosphate signal cascade is the primary contributor to the slow Ca²⁺ oscillation in both putative-neurons and astrocytes. The slow Ca²⁺ oscillation features multicellular synchrony, and both putative-neurons and astrocytes participate in the synchronous activity. Therefore, the mGluR5-dependent slow Ca²⁺ oscillation may involve in the neuron-glia interaction in the striatum.     

Resolution of DL-Glutamic Acid with Optically Active Neutral Amino Acid Amides

DL-Glutamic acid has been resolved into optically active forms as the diastereoisomeric salt of optically active neutral amino acid amides, and the salt is easily converted to the sodium salt of the active forms. By resolution with L-tyrosinamide and L-leucinamide, sodium L-glutamate was obtained in 65 and 80 per cent yield respectively. Attempts to extend this method to resolution of DL-glutamic acid using L-phenylalaninamide as resolving agent resulted in poor yield of less pure D-glutamic acid.

By the infrared spectroscopy and X-ray diffraction analysis it has been confirmed that the diastereoisomeric salts of L-leucinamide or L-tyrosinamide with L- or D-glutamic acid compose a combined salt structure in solid state, whereas L-phenylalaninamide with L- or D-glutamic acid does not compose a characteristic diastereoisomeric salt but rather the mechanical mixture of L-phenylalaninamide and L- or D-glutamate anion in solid state.

In the previous study¹⁾, it was reported that L-leucinamide forms the characteristic diastereoisomeric salts with racemic N-acyl mono amino acids, most of which are fairly resolved into their antipodes.     

Loss of Collapsin Response Mediator Protein 4 Attenuates 6-Hydroxydopamine-Induced Impairments in a Mouse Model of Parkinson’s Disease

Neurochemical Research - Parkinson's disease (PD) is a chronic neurodegenerative disorder characterized by impaired motor symptoms induced by the degeneration of dopaminergic neurons of the...     

The Formation of 2,6-Dihydroxy-phenylacetic Acid from Phenylacetic Acid by Various Fungi

Two principal toxins of diarrhetic shellfish poisoning, okadaic acid and dinophysistoxin-1, were esterified with 9-anthryldiazomethane in methanol. After cleaning with a Sep-pak silica cartridge column, the fluorescent esters were analyzed on a Develosil ODS column with MeCN- MeOH-H₂0 (8:1:1). The fluorescence intensities of both toxin derivatives measured at an excitation of 365 nm and an emission of 412 nm showed good linearity in the range 1 ~ 80ng.