Ultrastructure of bacteriophages used for typing of Staphylococcus aureus.

This paper reports the results of a study on the morphology, size and homogeneity of the bacteriophages used for typing Staphylococcus aureus. Fifty-five bacteriophages were studied. Preparations for the electron microscope were made directly from lysates or from purified and concentrated bacteriophages, and were contrasted with neutralized phosphotungstic acid (KPT) and examined under an electron microscope at x 40 000 microscopic magnification. The studied bacteriophages differed with regard to size and shape. The bacteriophages were classified into two morphological groups: BI and BIII. In the BI group, there morphological types were distinguished: B14, B15 and B16. Only one morphological type was distinguished in the BIII group, designated by the symbol BIII2. Only lysates of 42C, 70 and D bacteriophages contained virions of two morphological types: BI6 an BIII2. Until now, it is not clear whether the bacteriophages are a mixture of two different virions, or whether they represent variation in the size of their heads. Of the 55 bacteriophages studied, 25 were examined by other investigators. The results showed that of the 25 bacteriophages 5 belonged to different morphological types. It was concluded that the sets of standard bacteriophages should be checked by means of the electron microscope.

Antigenic similarity of morphologic type CIII1 bacteriophages.

The aim of the study was to demonstrate antigenic differentiation among bacteriophages belonging to the same morphologic type--CIII1 according to Krzywy and Slopek or A2 according to Ackermann. Twenty-six bacteriophages which multiplied on various strains of bacteria of the genera Escherichia, Shigella and Klebsiella, were studied. Serologic tests were done by the quantitative complement fixation test. Immune sera against 5 phi E. coli. D8 Sh. flexneri, G35 Sh. sonnei and Kl7 Klebsiella bacteriophages were obtained from rabbits. It was shown that bacteriophages of CIII1 morphologic type, with morphologically identical virion had different antigenic specificity. On the basis of results obtained the phages could be divided into eight serologic groups. The bacteriophages for which antisera were obtained belonged to four different serologic groups. All bacteriophages had some common antigens with 5 phi E. coli phage. The similarity points to a phylogenetic relationship among phages of CIII1 morphologic type.

Ultrastructure and antigenic differentiation of bacteriophages of the CII and CIII morphological groups.

45 bacteriophages of two morphological groups (CII and CIII) were serologically tested. The results point out the possibility of serological differentiation of bacteriophages within one morphological type. The aim of the undertaken studies was to examine ultrastructure and antigenic differentiation of bacteriophages belonging to CII and CIII morphological groups.

Actinomycetes of the genus Streptomyces in soil from Syria.

Species identification and antagonistic properties of 55 actinomycete strains isolated from Syrian soil were studied. The actinomycete strains belonged to 22 species, of which most abundantly represented were Streptomyces antimycoticus, S. rubiginosohelvolus, S. macrosporeus and S. coerulescens. Actinomycetes belonging to 16 species exhibited antagonism in relation to Gram-positive and Gram-negative bacteria, fungi and neoplastic cells.

Morphologic homogeneity of bacteriophages and their biological activity.

Lytic activity of morphologically homogeneous phage lysates, obtained from lysates containing morphologically inhomogeneous virions, was studied. Five series of phage lysates found to contain morphologically inhomogeneous virions were investigated. By selecting suitable hosts from each series, two or three lines were obtained which reproduced morphologically homogeneous virions. Morphologic homogeneity of these phage lines was determined by electron microscopy. In the course of this study it was found that phages with different morphologic appearance can produce similar plaques. Hence, appearance of plaques is not an adequate criterion of homogeneity of the phage. The isolated phages differed in biological activity from the original morphologically inhomogeneous bacteriophage. It was concluded that morphology is an important, and the most reliable at present, criterion of homogeneity of bacteriophages.