Isolated Bovine Spinal Motoneurons Have Specific Ganglioside Antigens Recognized by Sera from Patients with Motor Neuron Disease and Motor Neuropathy

The gangliosides GM1 and GD1b have recently been reported to be potential target antigens in human motor neuron disease (MND) or motor neuropathy. The mechanism for selective motoneuron and motor nerve impairment by the antibodies directed against these gangliosides, however, is not fully understood. We recently investigated the ganglioside composition of isolated bovine spinal motoneurons and found that the ganglioside pattern of the isolated motoneurons was extremely complex. GM1, GD1a, GD1b, and GT1b, which are major ganglioside components of CNS tissues, were only minor species in motoneurons. Among the various ganglioside species in motoneurons, several were immunoreactive to sera from patients with MND and motor neuropathy. One of these gangliosides was purified from bovine spinal cord and characterized as N-glycolylneuraminic acid-containing GM1 [GM1(NeuGc)] by compositional analysis, fast atom bombardment mass spectra, and the use of specific antibodies. Among seven sera with anti-GM1 antibody activities, five sera reacted with GM1(NeuGc) and two did not. Two other gangliosides, which were recognized by another patient's serum, appeared to be specific for motoneurons. We conclude that motoneurons contained, in addition to the known ganglioside antigens GM1 and GD1b, other specific ganglioside antigens that could be recognized by sera from patients with MND and motor neuropathy.     

Excretion of peroxidase from horseradish hairy root in combination with ion supplementation

Summary The effect of ion-supplemented medium on peroxidase excretion from horseradish (Armoracia rusticana) hairy roots was studied. Supplementation of mannitol instead of ions revealed that the excretion was stimulated not by osmotic pressure in the medium but by ionic properties. Extracellular peroxidase activity per dry cell was proportionally correlated with the ionic strength of the cations. CaCl₂ or MgCl₂ was found to be the most effective agent for excretion among other combinations. CaCl₂ supplementation at the beginning of the culture caused higher peroxidase production in the medium without a significant loss of final cell mass compared with CaCl₂ addition during the culture. Repeated batch culture with 50 mM CaCl₂ supplementation allowed a continuous retention of cell viability over 149 days and produced a great amount of extracellular peroxidase, 12-fold higher than that achieved in a 40-day-old batch culture with 50 mM CaCl₂ supplementation. Correspondence to: T. Kobayashi     

Verbascoside production by plant cell cultures

Verbascoside was found to be produced in all calli derived from eleven species that contained the compound in their leaves. Cell suspension cultures were also established in three species, i.e., Leucosceptrum japonicum f. barbinerve, Syringa josikaea, and Sy. vulgaris, all of which were found to produce verbascoside at more than 1 g/l. Of the three species, suspension cultures of L. japonicum f. barbinerve showed rapid growth and the highest yield of verbascoside (1.89 g/l). In these cultures, the effects of major salt concentration in B5 medium on cell growth and verbascoside production were examined. Maximum cell growth and maximum verbascoside production were both achieved by reducing the major salt concentration to half that of the original medium.     

One-electron reduction of the oxy form of cobalt-substituted hemoproteins

The reduction of oxy forms in cobalt-substituted hemoproteins by the hydrated electron (e(aq)-) was investigated by pulse radiolysis. The hydrated electron (e(aq)-) reacted with the oxy form of cobalt horseradish peroxidase (CoHRP) to form CoHRP. On the other hand, the initial product observed in the reaction of the oxy form of cobalt myoglobin (CoMb) with e(aq)- is neither CoMb nor Co3+ Mb. Subsequently, the product was found to convert to another form, the irreversible change in the porphyrin. In contrast to e(aq)-, both oxy forms of CoMb and CoHRP were reduced by various electron donors to form the cobaltic forms.     

Potentiation by BL191 of differentiation of neuroblastoma cells induced by dibutyryl cAMP and prostaglandin E1

BL191, a newly developed phosphodiesterase inhibitor, markedly potentiated a differentiation of neuroblastoma cell clones (Neuro2a, NS-20Y, and N1E115) induced by dibutyryl cyclic adensoine 3′:5′-monophosphate(dibutyryl cAMP) and prostaglandin E₁ (PGE₁). BL191 (1 mM) inhibited DNA synthesis more strongly when used together with PGE₁ (0.5 μg/ml) and dibutyryl cAMP (0.5 mM) than papaverine (1.6 μg/ml) alone did. The inhibition rates of DNA synthesis were 72.5% for N1E-115, 75.3% for Neuro2a, and 82.5% for NS-20Y. After the treatment with BL191. PGE₁, and dibutyryl cAMP for 48 h all of three cell lines became enlarged and flattened, and extended long processes. The specific activities of choline acetyl transferase (EC 2.3.1.9) of NS-20Y and dopamine β-hydroxylase (EC 1.14.17.1) of N1E-115 increased about 3-fold as compared to the controls. The tumorigenicities of Neuro2a and N1E-115 cells were decreased, but not of NS-20Y. These data suggest the heterogenous responsiveness in neuroblastoma cells to drug treatment.     

Human Ia molecules carrying DC1 or BR4X7 determinants are not homologous to murine I-E molecules

An anti-I-E^k alloantiserum was shown to react with purified human Ia preparation. All Ia preparations tested were actively bound irrespective of their HLA-DR phenotypes. However, from a quantitative point of view, DR7 molecules were significantly less reactive. No reaction was observed with isolated Ia subunits. Only molecules carrying DR determinants, but not those carrying either DC1 or BR4X7 determinants, were bound.     

A change in membrane microviscosity of mouse neuroblastoma cells in association with morphological differentiation

Changes in membrane microviscosity as well as in membrane constituents of mouse neuroblastoma clone N-18 were studied in association with neurite formation. The membrane microviscosity studied by fluorescence technique increased with the formation of neurites. The concomitant increase increase in the ratio of cholesterol to phospholipids was also observed.