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Summary A 0.1% solution of protein from the purified 20-nm particles of hepatitis-associated Australia antigen (HAA) has an optical density of 3.726 at 280 nm. The protein appears to consist of two subunits; it contains a high proportion of proline, leucine and serine and a low content of tyrosine. Depending upon the anti-HAA reagent used, the hemagglutination inhibition assay can detect HAA protein in amounts as low as 1 to 60 ng.

A solid-phase enzyme immunoassay is described for measuring hepatitis B surface antigen in human serum or plasma. Immunologically purified antibody labeled with horseradish peroxidase was used as the indicator. In the assay system, antibody-coated controlled-pore glass is used as a solid support and there are three sequential incubations, totaling 2 h, at room temperature. Results for serially diluted positive and reference sera compare favorably to radioimmunoassay in sensitivity and specificity.

A Sex-Associated Protein in Liver Tissue of the Rat and its Response to Endocrine Manipulation

A solid-phase enzyme immunoassay is described for measuring hepatitis B surface antigen in human serum or plasma. Immunologically purified antibody labeled with horseradish peroxidase was used as the indicator. In the assay system, antibody-coated controlled-pore glass is used as a solid support and there are three sequential incubations, totaling 2 h, at room temperature. Results for serially diluted positive and reference sera compare favorably to radioimmunoassay in sensitivity and specificity.

High-titered yields of human cytomegalovirus (CMV), strain AD 169, were produced in WI-38 cells in large roller bottles. Maximum plaque titers were observed by the 4th day after infection at which time infectivity in the medium was 200 times greater than that associated with the cells. Virus released into the medium was recovered by sedimentation in a sucrose gradient in a continuous-flow centrifuge rotor. Maximal viral infectivity was found at a sucrose concentration of 42%, equivalent to a density of 1.18 g/cm 3 . Deoxyribonucleic acid extracted from these preparations was about 80% viral and 20% cellular as judged by equilibrium centrifugation in cesium chloride density gradients.

The 5.2 hr X-ray binary 4U 2129+47 was observed for a full orbital cycle using the imaging proportional counter detector and the monitor proportional counter detector aboard the Einstein Observatory, as well as a 0.9 m reflector for 5 hrs continuous optical photometry. The X-ray and optical light curves, the X-ray spectrum, and the times of optical and X-ray minimum were determined. The shape of the 5.2 hr X-ray light curve is independent of energy. A partial X-ray eclipse occurred which was centered on the time of optical minimum and which lasted 20 percent of the orbital period. During this interval the X-ray intensity varied smoothly by a factor of three, and the light curve was symmetric relative to the time of minimum. These findings argue that the X-ray emitting region is extended and highly ionized. A model is presented in which an accretion disk corona scatters radiation from a central accreting neutron star.

The Perek-Kohoutek planetary-nebula catalogue was searched for coincidences with the Kukarkin et al. variable-star catalogue. Twenty-six objects appear in both catalogues, but only one, the eclipsing binarv UU Sge, appears to be a genuine new variable planetary-nebula central star. The majority of the coincidences are with late-type variable stars erroneously listed as planetary nebulae. Key words: eclipsing binaries - planetary nebulae - symbiotic variables - variable stars

Slit spectrograms have been obtained and classified for 84 little-studied blue variable stars at high galactic latitudes. Several of the objects are newly recognized nova-like or RR Lyrae-type variables, and one is a symbiotic variable.

The historical light curve of the nova-like variable CD - 42 14462 = V3885 Sgr has been determined on 270 plates from the archival collection at Harvard. The object has remained at about B = 10.3, with random excursions of a few tenths of a magnitude up or down, since 1899. The bulk of the observational evidence supports the conclusion that CD -42 14462 is a dwarf nova in a state of permanent outburst. Key words: dwarf novae-close binaries-variable stars

The zonal centrifuge has been used to purify viruses, subcellular organelles and macromolecules of biologic interest. In this report we describe a preparative zonal ultracentrifugation method for the separation from serum of chemically and functionally highly purified first component (C′1) of guinea pig and human complement. The observation that the sedimentation rate of C′1 varies inversely with the ionic strength of the medium made the development of this purification procedure possible. At an ionic strength of 0.3 or greater the sedimentation constant of C′1 is about 4 and at an ionic strength of 0.15 or less the sedimentation constant of C′1 is about 18. The purification procedure consists of a two-cycle centrifugation: the first at µ = 0.75 separates C′1 from 19 S serum proteins; the cycle at µ = 0.065 separates C′1a, now an 18 S molecule, from the smaller molecules.