Host-range and partial characterization of several new bacteriophages for Bacillus megaterium QM b1551

Several phages infecting Bacillus megaterium QM B1551 have been isolated from the soil and partially characterized. These phages, designated MP9 to MP50, were tested for host-range on several strains of B. megaterium and 13 other Bacillus species. All the phages only infected B. megaterium and on the basis of host-range patterns, 23 groups could be distinguished. The phage patterns also distinguished subgroups of B. megaterium strains within the species and should be useful in phage typing. The phages have varying sensitivities to heat, salts and organic solvents and are all double-stranded DNA phages. Thirty-two have been examined by electron microscopy and are Bradley types A, B and C. This is the first large collection of B. megaterium phages that has been characterized.

Characteristics of a new bacteriophage, Psp231a, infecting Pseudomonas phaseolicola HB10Y

Bacteriophage Psp231a infects Pseudomonas phaseolicola, strain HB10Y, which is the host cell for the enveloped bacteriophage phi 6. This paper describes the biophysical characteristics of Psp231a and the physical properties of its nucleic acid. In electron micrographs the virion appears as an icosahedral structure, approximately 55 nm in diameter, with a short tail. The virion density is 1.48 g/cm3 in CsCl, and the sedimentation coefficient is approximately 407S. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the presence of 12 polypeptides ranging in molecular weight from 5,000 to 117,000. The nucleic acid of Psp231a is linear, double-stranded DNA of molecular weight 28 X 10(6). Its density in CsCl is 1.716 g/cm3, and its sedimentation coefficient in 3 M CsCl is 20.0S, corresponding to an S020,W of 34S.

Typhoid fever: A report on a point-source outbreak of 69 cases in Cape Town

In 1978, after a party in a Cape Town suburb attended by several hundred people, 69 persons were treated for typhoid fever. The precise source of the infection could not be traced, although it is reasonable to suppose that food eaten at the party had been contaminated by the main caterer. All 57 cultures of Salmonella typhi phage-typed were of phage type 46, including that obtained from the stool of the main caterer, who was asymptomatic. An epidemiological profile of the cases and an account of the management of the outbreak is given. There were no deaths and no patient became a carrier. Although the outbreak was contained, certain problems relating thereto are aired, including in particular the potential hazard of food-borne disease wherever housing and environmental standards are low.

Phage type/biotype groups of Salmonella typhimurium in Scotland 1974-6: variation during spread of epidemic clones

Biotyping by the scheme of Duguid et al. (1975) of 2010 cultures of Salmonella typhimurium received by the Scottish Salmonella Reference Laboratory in 1974--6, the definitive phage types of which were known, revealed 137 different phage type/biotype groups. Four major epidemic clones, comprising 52% of the cultures, were recognized: 1/2a, 49/26a, 56/17g and 141/9f. The sources of each of these four groups of strains were primarily bovine (587 cultures) and human (361), suggesting a close association between infections in the two hosts. Epidemiological evidence showed that most of the outbreaks were caused by cultures of a single phage type/biotype, suggesting that both phage typing and biotyping characters were usually stable in the course of spread of epidemic strains. Thirty-two of the 63 phage types contained strains of more than one biotype. Cultures from 11 of the phage types were of two or more closely related biotypes and those from 21 others were of unrelated or distantly related biotypes. The combined use of phage typing and biotyping made it possible to detect occasional variations in the phage type or biotype in epidemic clones during their spread, e.g. phage type 49 to 204, 56 to 193, 141 to 193 and biotype 2a to 10a, 9f to 9bf, or 9cf, 26a to 26f.

DNA base composition, nature of intracellular DNA, morphology, and classification of bacteriophages infecting Micrococcus luteus

Ten bacteriophages infecting Micrococcus luteus have been characterized. All phages contain double-stranded DNA, of 64.3--73.5 mol% guanine plus cytosine (GC). The DNA of phage N7 has the highest GC content reported for any bacterial virus. No unusual bases have been found. The intracellular replicating DNAs of six phages are covalently closed circular molecules. All 10 phages have isometric, probably icosahedral, heads and long, flexible, noncontractile tails and can be sorted into two morphological groups based on size and presence or absence of a collar. Host-range studies indicate six host-range groups.

Bacteriophages of Bacteroides

Sixty-eight bacteriophages specific for nine species (DNA homology groups) of Bacteroides were isolated from sewage. Four distinct morphological types were isolated, three of which had not previously been described. Attempts to use these phages to transduce Bacteroides fragilis were unsuccessful. A total of 91 phage-susceptible strains of Bacteroides were used with these phages in a study of the feasibility of developing a scheme for identification of Bacteroides species. Blind trials were performed with 10 B. fragilis-specific phages and a collection of over 200 bacterial strains, including 144 strains of B. fragilis. Of the strains of B. fragilis, 78% were identified correctly within 24 hr. A phage-carrier state, or pseudolysogeny, was observed with most of the phage-host systems, and this state was studied in detail with B. fragilis phage Bf-1. The presence of a thick capsule around some cells in a pure culture of a host strain appears to render these cells resistant to phage infection, thus perpetuating the carrier state. It is suggested that such capsules may play a role in the virulence of strains of Bacteroides.

Partial characterization of a cubic Bacillus phage

Partial characterization of a cubic Bacillus phage. Can. J. Microbiol. 24: 986--993. Phage Bam35 is an icosahedron of about 63 nm in diameter. It has a double capsid with spikes at the vertices, and a tail which seems to appear upon nucleic acid ejection. The phage contains DNA and, probably, lipids which seem to be located in the inner coat. The phage is Bacillus-specific, UV- and lipase-resistant, and sensitive to heat, chloroform, and ether. The latent period is 50 min and the burst size is 39. Page Bam35 belongs to a new virus group which includes a phage of B. anthracis and four phages of gram-negative bacteria harboring drug-resistance plasmids.

Isolation of bacteriophage from Thermoactinomyces

Bacteriophages were isolated from strains of Thermoactinomyces vulgaris, T. candidus, and T. sacchari used to produce antigen for hypersensitivity pneumonitis screening at the Marshfield Medical Foundation. Whereas the one phage isolated from T. sacchari and two phages from T. vulgaris were species specific, three other phages isolated from T. vulgaris and the two phages isolated from T. candidus were infectious for both T. vulgaris and T. candidus, thus indicating a close relationship between these two species. A simple reproducible scheme for classification of newly isolated T. vulgaris-T. candidus phages into seven groups on the basis of host range is presented. Examination of plaque morphology of the T. vulgaris-T. candidus phages supported the host range classification scheme. The ease of isolation of phages from cultures of Thermoactinomyces suggests that they are commonly associated with this genus.

Virometer: an optical instrument for visual observation, measurement and classification of free viruses

An instrument based on fluorescence correlation spectrometry and total reflection fluorescence visually and photoelectrically detects and sizes viruses at moderate concentrations in biologic fluids in minutes. Viruses can be classified using their nucleic acid type and amount determined by new fluorescent staining and data handling techniques.

Antigenicity of converting phages obtained from Clostridium botulinum types C and D

Phage conversion of toxigenicity in Clostridium botulinum types C and D was accomplished by using nontoxigenic strains and phages purified from plaques. Although the morphology of the converting phages seemed to be the same, they were divided into three groups on the basis of their conversion spectrum. The first group consists of phages obtained from toxogenic strains C-Stockholm and C-468. The second group consists of phages from strains D-1873 and C-203. The third group consists of phages from strains D-South African and D-4947. These converting phages were also classified into the same three groups by a neutralization test with specific antiphage sera. Cross-neutralization, however, was observed between phages belonging to group 1 and group 2,by both the neutralization test of converting ability and by a plaque experiment in which the surviving rates of phages were calculated after treatment with each antiphage serum. The antigenic differences among these converting phages should probably comprise one of the reasons for the existence of the specific infection spectrum in C. botulinum types C and D.

[Immunochemical and molecular biological characteristics of dysentery phages]

Molecular organization of DNA of six dysentery phages was studied for their classification. The pattern of glucosilation of their DNA was determined by an immunochemical method and the test of competitive hybridization established the degree of homology of these DNA in relation to T4 phage DNA. Four of the phages (DDVI, Zonne "Gorkyi" Zonne "Czechoslovakia", Zonne "Poland") were shown to belong to the group of T-even phages by their pattern of DNA glucosilation and by their capacity to inhibit DNA T4X3H DNA T4 hybridization. According to these criteria, two other phages (Zonne "Ufa" and Zonne "Khabarovsk") do not belong to the group of T-even phages.

[Comparative study of moderate and virulent phages of mesophilous lactic acid streptococci]

A method has been developed to identify phage containing mesophilous lactic acid streptococci. The method is based on the chloroform treatment of young cultures. The isolated moderate phages P4St and P6St are morphologically identical and serologically related to one another and to virulent phages P1Sv, P2Sv, P3Sv, P12Sv, P13Sv that can be isolated in industrial phagolysis.

[Morphology of the temperate plague phages 1701 and 1710 and their mutants]

A study was made of the morphology of plague moderate bacteriophages 1701, 1710 and their mutants 1701-1 and 1710-1. The phages proved to be morphologically identical, were referred to group 5, and were identical to the moderate plague H-phages; when confronted to the commonness of the serological properties and a number of other signs this indicated their affinity.

Genetic studies on temperature-sensitive mutants of Bacillus subtilis bacteriophage SPP 1

A total of 30 ts mutants of Bacillus subtilis bacteriophage SPP1 were isolated and subjected to complementation test. On the basis of this test 21 mutants were classified into 4 functional groups; the classification of the remaining 9 mutants was unclear. The frequency of recombination by mutual crossing was determined in representatives of individual groups; this made it possible to place these mutants on a linear map comprising a total length of 7.62 recombination units.