Article

Lysis of T4 phage by the specific lipocarbohydrate of phase II Shigella sonnei

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Abstract

When the specific lipocarbohydrate of Phase II Sh. sonnei and T(4) phage react in vitro, the virus is rapidly inactivated and the content of the viral membrane is released into the surrounding medium. The reaction between phage and lipocarbohydrate proceeds only in the presence of a lipide constituent which can be extracted from the polysaccharide, rendering the latter inactive, and which can be replaced by certain fatty acids. It has been suggested that the lipocarbohydrate is the receptor substance of the Phase II bacillus which specifically combines with and brings about disintegration of the virus when the latter infects the host cell.

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... While sample preservation, cell lysis and WGA protocols have been tested for SCGs (Woyke et al., 2011;Clingenpeel et al., 2014;Chen et al., 2018), more thorough testing in each of the fundamental methodological SVG steps is needed to achieve the full potential of this approach (Fig. 1). To evaluate the efficiency of the tested approaches in recovering viral genomes, we employed sorted single viral particles of the Escherichia coli T4 virus as a model (Jesaitis and Goebel, 1955;Jesaitis, 1957;Miller et al., 2003), and we tested some of the approaches on marine environmental viruses. Based on our findings, we provide specific SVG methodological recommendations and discuss some of the limitations and biases of this novel methodology that will help to expand our knowledge in the uncultured virosphere. ...
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Chapter
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Chapter
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Chapter
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Article
1. A phage-resistant variant of Phase II Shigella sonnei has been isolated and the type-specific antigen from it has been obtained. 2. The antigen of the variant microorganism, II/3, 4, 7, differs from that of the parent Phase II bacillus in serological specificity and in chemical make-up. 3. Although the antigen of Phase II Sh. sonnei inhibits all T phages to which the bacillus is susceptible, that of the variant fails to inhibit T(3), T(4), and T(7).
Article
1. The somatic antigen of Phase II Shigella sonnei can be isolated by extracting phenol-killed microorganisms with water. This substance inactivates all T phages to which this bacillus is susceptible. 2. The Phase II antigen is constituted from a protein and a phosphorylated lipocarbohydrate. The major portion of the protein component can be removed by digestion with pancreatin. The enzymatically degraded antigen thus obtained can be further dissociated into its protein and lipocarbohydrate components by treatment with 90 per cent phenol. Glucose, galactose, glucosamine, and an aldoheptose have been identified as the monosaccharide constituents of the lipocarbohydrate.
Article
Excerpt It is now reasonably certain that bacteriophage undergoes disintegration when it encounters a susceptible microörganism; only part of the phage material penetrates the host and the viral membrane remains attached to the exterior of the bacterium (Hershey and Chase, 1952). The nature of the substances involved in this event is not fully understood. It has been shown, however, by earlier investigators that different microbial species, all susceptible to the same phage, apparently have surface antigens which are closely related. Cell-free extracts of such bacteria are capable of inactivating the virus in vitro. In several instances it was found that the antiviral activity of such extracts could be attributed to the presence of a serologically active component, — a carbohydrate or a more complex substance containing immunologically active polysaccharide (Burnet et al., 1937). It has been suggested that this substance serves as the specific receptor for the phage in question. Recently...
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Excerpt Investigations of the physical properties of viruses have been extensively undertaken only since about 1935, since it had not been clear before then that viruses were particles which could be sufficiently purified to render their physical study significant. In the last two decades, however, a large amount of information has been obtained with the aid of ultrafiltration, analytical ultracentrifugation, electrophoresis, diffusion and viscosity, X-ray diffraction, and electron microscopy. These methods of physical measurement have been combined to give us considerable information about the shape and size of viruses, their density and particle weight, their internal structure, and their degree of hydration. Knowledge of the physical characteristics of viruses fits into our over-all understanding of their growth and multiplication primarily by establishing certain tangible specifications for the properties which the finished, mature particles must have. Any acceptable hypothesis about modes of reproduction must account for the formation of mature particles with...
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It has been shown that phase variation of Sh. sonnei is accompanied by changes in morphology and antigenic structure. Two mutants of the Phase I organism (II(S) and II(R)), which were studied, elaborate somatic antigens which are immunologically identical. The purified lipocarbohydrate-protein antigens of the Phase I and II(S) microorganisms are chemically similar yet immunologically distinct and specific. By inference the same should hold true of the antigen of II(R), but it has not yet been investigated in this relation. It is suggested that when Sh. sonnei undergoes variation from Phase I to II(S) the immunological changes occurring are dependent upon a change in the enzyme systems responsible for the synthesis of the lipocarbohydrate-protein constituent.
Article
Phase I and Phase II Sh. sonnei exhibit differences in their susceptibility to the T series of bacteriophages. Both microorganisms are lysed by T(2) and T(6), but only the Phase II bacillus is lysed by T(3), T(4), and T(7). Lysis of the Phase I or Phase II bacillus by T(2) or T(6) is not inhibited by the homologous type-specific antigen. In the presence of an appropriate cofactor, however, the lysis of Phase II Sh. sonnei by T(3), T(4), and T(7) is specifically inhibited by the homologous somatic antigen but not by the Phase I antigen. The significance of these observations is discussed in respect to the nature of the virus receptor of these microorganisms.
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