Mucins are the principal organic constituents of mucus, the slimy visco‐elastic material that coats all mucosal surfaces. Compelling evidence suggests that they play an integral role in non‐immune protection of the oral cavity. Specific protective functions include: 1) protection against desiccation and environmental insult, 2) lubrication, and 3) antimicrobial effects against potential pathogens. Biosynthesis of mucin is regulated by both intrinsic (“cooperative sequential specificity”) and extrinsic (“structural modulation”) controls. These controls form the basis by which mucin's structure can be modified to meet a dynamically changing biological need.
Four highly purified salivary glycoproteins were used to study salivary-bacterial interactions. One pair of glycoproteins was mucin-like in composition, whereas the second pair was not. By an agglutination assay, it was found that only the mucin-glycoproteins agglutinated Streptococcus sanguis and S. mutans. Removal of sialic acid from these molecules resulted in a loss of agglutination of S. sanguis but not of S. mutans. The agglutination phenomenon was shown to require a salivary macromolecule of at least 150,000 daltons.
The mode of development of herpes simplex virus has been the object of periodic study ever since Lipschiit2, (1) discovered that intranuclear inclusion bodies characteristically appear in the cells of tissues infected by this agent. Interest has centered chiefly on attempts to determine the nature of the nuclear changes but the results have not been concordant. Some observers have concluded that the inclusions actually represent a stage in viral multiplication and are composed at least in part of viral material. Others have inferred that they consist solely of abnormal products of cellular metabolism. The earlier work bearing on this subject has been well reviewed by Van Rooyen and Rhodes (2). More recently, Crouse et al. (3) carried out histocbemical studies which revealed a distinct accumulation of desoxyribese nucleoprotein in early nuclear inclusions. This work was confirmed by Wolman and Behar (4) who considered the findings to be corroborative of the hypothesis that the herpetic inclusion body represents a colony of virus inside a cellular matrix. Scott el al. (5) have extended these observations by a careful study wherein the development of infectious virus was followed in temporal relation to the cytologic changes. These authors concluded that the nucleus probably contains virus during the early formation of the inclusion body. In contrast, Francis and Kurtz (6) and Ackermann and Kurtz (7) reported data on the infectivity of cellular fractions obtained by differential centrifugation which they interpreted as indicating that herpes simplex virus is not associated with the nucleus.A more direct approach to this problem can be made by examining infected tissues in the electron microscope. Morgan et al. (8) have previously reported that altered nuclei could easily be identified by means of the electron micro-* This investigation was supported by grants from
Examination in the electron microscope of ultracentrifuged preparations of vaccinia and fowl pox viruses has shown the particles generally to be brickshaped with dimensions about 210 X 210 X 260 m/~ and 265 X 265 X 330 m/~, respectively (1).In 1942, Green, Anderson, and Smadel (2) noted that va~cinia virus appeared to have a limiting membrane and an internal structure composed of a central zone of greater density, often surrounded by four small bodies. The presence of an inner body was confirmed by Sharp e~ a2. (3). Dawson and McFarlane (4) observed that the central body resisted pepsin digestion, whereas the peripheral area became less opaque to the electron beam. They noted a limiting membrane but suggested that the satellite bodies, described by Green a 02., were artefacts. Internal structure has also been seen by others (5-7), and Peters and Nasemann (8) have illustrated and described a small, dense body located at the periphery of some viral particles, which they consider to represent developmental forms. Bang e~ 02. (9) observed a dense, central body in fowl pox virus and also noted a decrease in density at the periphery of the virus particle after treatment with pepsin.Although vaccinia (10, 11) and fowl pox (12) viruses have previously been identified in sectioned tissues, the relatively thick sections employed and the distortion produced by removal of the embedding plastic with solvents have tended to obscure details of viral structure. More recently, Gaylord and Melnick (13), employing thinner sections without removal of methacrylate, noted several forms of vaccinia virus, including "empty circles" and "circles filled with homogeneous material of low electron density," as well as internal structures described as granules, bars, and dumbbells.In order to obtain further information concerning the structure and development of vaccinia and fowl pox viruses, ultrathin sections of infected * This investigation was supported by grants from
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