Councilman Morgan

ASSOCIATION BETWEEN POLYARTERITIS AND AUSTRALIA ANTIGEN

Abstract Four of eleven patients with biopsyproven polyarteritis nodosa were also found to have Australia (Au) antigenaemia. The four Au-antigen-positive patients exhibited a typical polyarteritis syndrome, but differed from the seven antigen-negative patients in that they also had evidence of mild hepatic damage. The presence of circulating immune complexes in the sera of three of the four Au-antigen-positive patients was demonstrated by serological, ultracentrifugal, and electro-microscopic studies. These complexes were further shown to be composed of Au antigen and immunoglobulin. Immunofluorescent studies of tissue from one of the patients revealed deposition of Au antigen, IgM, and β 1 C in blood-vessel walls.

Vaccinia virus reexamined: development and release.

Abstract Vaccinia virus was examined in thin sections by electron microscopy at intervals after release of infected cells from hydroxyurea, which permits the synthesis of early proteins but blocks DNA replication. There was sufficient synchrony in the ensuing process of development to recognize early stages. The foci of assembly lack polyribosomes and endoplasmic reticulum suggesting that the late proteins, at least, are synthesized elsewhere in the cytoplasm and transported to the maturation sites. The proposal by previous investigators that the surface spicules account for the contour and rigidity of the trilaminar membrane enclosing immature forms of the virus is consistent with the present study. The nucleoprotein appears to be inserted into the immature virus and to condense into the nucleoid just before closure of the envelope. The nucleoid is believed to move from its eccentric position to the center of the particle and there to become transformed into the biconcave disc characteristic of the mature, infectious virion. Previous reports were confirmed that virions are packaged by membranes of the Golgi apparatus and transported to the cell surface where they are released by exocytosis.

The effect of hydroxyurea on virus development. II. Vaccinia virus.

Abstract Hydroxyurea in appropriate concentration inhibits the formation of mature infectious particles of vaccinia virus without preventing the synthesis of viral protein. Development of the virus is arrested at the “immature” or single-membrane stage, and the viral particles lack the internal body or “nucleoid” that is normally present. Hydroxyurea appears to act by inhibiting the synthesis of viral DNA.

IMMUNOCHEMICAL STAINING FOR ELECTRON MICROSCOPY

The successful al)plication of imntunofluorescent staining in so many branches of biological science has prompted a search for a comparable antibody label which can utilize the higher resolution afforded by electron microscopy. Such a label must have sufficient size and electron-scattering power to be readily discernible against the usual background of biological specimens. A number of methods for employing the specificity of the antibody-antigen reaction for electron microscopic cytology have been proposed and tried. By means of unmodified antibody alone (13) and even more effectively by antibody substituted with heavy metals (1 1 , 12, 22) the presence of antigen may be recognized by virtue of a diffuse increase in electron-scattering due to the bound antibody. Individual antibody molecules and their specific sites of attachment cannot be readily discerned, however, by these techniques. In 1959 Singer proposed the use of the ironcontaining protein, ferritin, a.s a label which would permit the recognition of single antibody molecules (18). Coupling of antibody and fermitin may be accomplished by means of a number of small, bifunctional molecules including nz-xylylene diisocyanate (18), toluene diisocyanate (19) and p ,p’-difiuoro-nu ,m’-dinitrophenylsulfone (14). In each case one active group is available for reaction with ferritin and the other with globulin. The chemical aspects of these reactions and some of the properties of the conjugates have been described (3, 14, 17, 19, 21). Itis the purpose of this communication to elaborate upon certain aspect-s of Singer’s original conjugation procedure which appear to be responsible for a relatively high rate of successful coupling and a satisfactory yield of conjugated antibody. In addition, examples of

Electron microscopic observations of visna virus-infected cell cultures.

Abstract Electron microscopic observations of three cell lines infected with visna virus revealed two types of extracellular particles. The smaller of these was 65–110 mμ in diameter and contained a 20–30 mμ electron-dense core. Ordered arrays of the latter type of particle occurred rarely in the cytoplasm. After cesium chloride density gradient centrifugation of the virus, the band that contained maximal infectivity was composed of numerous particles with osmiophilic cores similar to those found in infected cell cultures. This finding suggests that such particles represent the infective agent. The second type of extracellular particle was larger (100–140 mμ in diameter), lacked an electron-dense core, and contained material similar in appearance to cellular cytoplasm. This form appeared to develop by budding from the cell surface.

An Electron Microscopic Study of Changes at the Surface of Influenza-Infected Cells as revealed by Ferritin-Conjugated Antibodies.

The sequence of events associated with liberation of the PR8 strain of influenza virus at the surface of chorioallantoic membranes (CAM) was studied by means of ferritin-conjugated antibodies, one of which was specific for the V antigen of the virus and the other for host cell antigen. With an input multiplicity of approximately 0.001 per cell, viral progeny were first detected by infectivity titrations and electron-microscopy after 12 and 13 hours, respectively. As infection proceeded, viral antigen progressively accumulated at the cell surface, while host cell antigen diminished in amount. It was concluded that normal host cell protein did not constitute an integral part of the surface structure of the virus.

The Use of Ferritin-Conjugated Antibodies in Electron Microscopy

Publisher Summary This chapter discusses the blocking technique as a control for the specificity of antigen–antibody reactions in tissue. If unconjugated antibody is applied, followed by the conjugate, there are very few free antigenic sites where tagging could occur. In actual practice, however, a relatively complete block is rarely seen. There is usually a reduction in the amount of tagging, but preparations are seldom devoid of ferritin. One of the major drawbacks associated with the use of ferritin-conjugated antibodies is their large size. Ferritin is approximately 100 A in diameter, whereas the antibody is about 250 A long and 35 A wide. To reduce the dimensions of the conjugate, ferritin is coupled with an active fragment of the antibody obtained by papain digestion. The challenge that remains is to develop techniques for labeling thin sections themselves. With this accomplishment, ease, consistency, and a high degree of specificity can be reached in the study of fine structure.

Serial sections of vaccinia virus examined at one stage of development in the electron microscope

Abstract Two clusters of intracytoplasmic viral particles are illustrated in eight consecutive serial sections. The sections average 30–33 mμ in thickness. The viral particles are spherical with diameters varying from 200–240 mμ. They possess a dense, limiting membrane 9–12 mμ thick. All particles sectioned five or more times can be shown to contain a nucleoid at one stage of development.

Unusual growth properties of a bacterial strain lacking DNA polymerase

Summary The DNA polymerase-deficient E . coli strain pol A1− exhibits a 5% plating efficiency when grown on synthetic liquid medium and plated on a nutritionally rich solid medium. This phenomenon is not seen when the composition of the liquid and solid media is identical. Accordingly in order to obtain meaningful results with this strain, the growth conditions must be controlled carefully.

Electron microscopic study of the development of herpesvirus saimiri

Abstract Electron microscopic study of herpesvirus saimiri in thin sections of infected OMK and Vero cells showed the apparent intranuclear envelopment of capsids by membranes of vesicles. Clusters of filaments were also encountered. Numerous unenveloped intracytoplasmic capsids were observed in cells devoid of nuclear changes, raising the possibility that differentiation can occur within the cytoplasm.