Tomoaki Kohama

Isolation and characterization of two distinct types of HVJ (Sendai virus) spikes

Abstract Solubilization of the envelope of HVJ (Sendai virus) with alkali-Tween 20 and subsequent fractionation by sucrose density electrofocusing in the presence of Tween 20 resulted in the separation of two biologically distinct glycoproteins: one protein banded at pH 4.9 without hemagglutinin and neuraminidase activities (HANA − ) and the other at pH 6.5 with both hemagglutinin and neuraminidase activities (HANA + ). Morphologically, both fractions consisted of dumbbell-shaped spikes, with HANA − spikes exhibiting more definite contour in or shape of knob and shaft than HANA + spikes. Serologically, HANA − and HANA + spikes were distinct from each other in micro-Ouchterlony test. Moreover, SDS-polyacrylamide gel electrophoresis revealed that HANA − spikes were composed of two species of glycoproteins, VP4, (MW, 51,000) and SGP (MW, 15,000), while HANA + spikes contained single glycoprotein, VP2 (MW, 67,000). Radioactivity of HANA − spike fraction did not adsorb onto chicken erythrocyte ghosts, whereas radioactivity, neuraminidase, and hemagglutinin activity of HANA + spike fraction adsorbed onto the ghosts. No hemolytic activity was detected in either HANA − or HANA + spike fractions.

Rearrangement of 4,5-epoxy-eudesmanes with boron trifluoride

Abstract Three epoxides (IX, XIX and XX) prepared from the eudesm-4-enes (VIII and XVIII) on treatment with BF 3 -etherate have been found to undergo skeletal rearrangement resulting in the formation of a number of ketones; i.e. 5- epi faurinan-4-one (X), 1( R )-isopropyl-3-(1′-methyl-5-oxohexylidene)cyclopentane (XI) and 1( S ),7( S )-dimethyl-4( R )-isopropyl-bicyclo[5.3.0]decan-6-one (XII) from 4α,5α-epoxy-10- epi eudesmane (IX), 1( R ),7( S )-dimethyl-4( R )-isopropyl-bicyclo[5.3.0]decan-6-one (XXI) from 4α,5α-epoxy-eudesmane (XIX), and the unsaturated methyl ketone (XI) from 4β,5β-epoxy-eudesmane (XX).

Carbohydrate composition of the envelope glycoproteins of Sendai virus

Abstract The carbohydrate composition of the two envelope glycoproteins and glycolipids of Sendai virus was determined by gas chromatographic analysis. The larger glycoprotein (HANA), which bears neuraminidase and hemagglutinin, was found to contain approximately 9% carbohydrate by weight, and the smaller glycoprotein (F) approximately 15%. Fucose, mannose, galactose, and N-acetylglucosamine were found in both the glycoproteins, but less fucose and N-acetylglucosamine were present in the HANA glycoprotein than in the F glycoprotein. The main carbohydrate components of the glycolipids are galactose and glucose. Sialic acids have been found to constitute less than 0.01% of the virion. Each radiolabeled glycoprotein was digested with pronase and then subjected to gel filtration using a Bio-Gel P-6 column. Oligosaccharides from the HANA glycoprotein were found to be composed of two distinct types of carbohydrate chains, whereas those from the F glycoprotein were found to be composed of a single type of carbohydrate chain. Possible structures of the oligosaccharides from each glycoprotein are proposed. The amino acid composition of each glycoprotein was also analyzed.

Biosynthesis of ponasterone A and ecdysterone from cholesterol in Podocarpus macrophyllus

Abstract Administration of cholesterol-4- 14 C to Podocarpus macrophyllus seedlings resulted in the formation of the insect-metamorphosing substances ponasterone A and ecdysterone in radioactive form.