Morphology of Newcastle bacteriophages]

A study was made of morphology of 6 clones of Newcastle bacteriophages of different origin divided into 3 types. Bacteriophage H-18 referred to the III morphological type by the Tikhonenko classification was characterized by a comparatively short process and a head in the form of an isometric polyhedron; H-1, H-5, H-10 and H-17 bacteriophages referred to type V, despite their antigenic difference were morphologically identical: they had a comparatively large head in the form of an elongated polyhedron and a process with a complicated structure ending by a besal plate with 3 indentions originating from it. Bacteriophage H-4 was referred to the IV type and was characterized by a head in the form of an elongated polyhedron and a long curved noncontracting process; in difference from the others it had no basal plate on the end of the process. The revealed morphological peculiarities of the particles of the Newcastle bacteriophages only partially correlated with their division on the basis of serolological properties and the size of the negative colonies.     

Morphology of Staphylococcus saprophyticus bacteriophages

The morphology of 6 bacteriophages isolated from Staphylococcus saprophyticus was studied by electron microscopy.Phages had isometric heads and non-contractile tails, thus belonging to the Siphoviridae family. They were subdivided into two morphological groups based on head diameter and tail length. Type I, represented by phages 1154A and 1405, and characterized by an unusually small capsid, may be a new species.     

Morphology of Pasteurella multocida bacteriophages

Twenty-one tailed phages with icosahedral heads belong to the Myoviridae, Siphoviridae, and Podoviridae families and to four morphological types. Type AU, with 10 phages, has a contractile tail and is morphologically identical with coliphage P2. Lysates contain contracted tail sheaths assembled end-to-end and abnormal structures with long tails and multiple tail sheaths. Types C-2 and 32, with one and three phages, respectively, have long, noncontractile tails. Type 22 includes seven phages, has a short tail, and resembles coliphage T7. Our results agree with previous biological data and suggest that types AU, C-2, 32, and 22 correspond to four different phage species.     

Comparative study of nine Lactobacillus fermentum bacteriophages

AIMS: To investigate the basic properties of six temperate and three virulent phages, active on Lactobacillus fermentum, on the basis of morphology, host ranges, protein composition and genome characterization. METHODS AND RESULTS: All phages belonged to the Siphoviridae family; two of them showed prolate heads. The host ranges of seven phages contained a common group of strains. SDS-PAGE protein profiles, restriction analysis of DNA and Southern blot hybridization revealed a high degree of homology between four temperate phages; partial homologies were also detected among virulent and temperate phages. Clustering derived from host range analysis was not related to the results of the DNA hybridizations. CONCLUSION: The phages investigated have common characteristics with other known phages active on the genus Lactobacillus. Sensitivity to viral infection is apparently enhanced by the presence of a resident prophage. SIGNIFICANCE AND IMPACT OF THE STUDY: These relationships contribute to the explanation for the origin of phage infection in food processes where Lact. fermentum is involved, such as sourdough fermentation.     

Morphology of the fruiting pustules in the genus Pestalotia

Summary The morphology of fruiting pustules in six isolates ofPestalotia causing the leaf spot diseases ofSyzygium cumini, Eugenia heyneana, Carissa congesta, Madhuca indica, Mangifera indica andPsidium guajava was studied. On the first two hosts both pycnidial as well as acervulus like fruiting bodies were produced. OnMadhuca indica the structure of fructifications varied on the two surfaces of the leaf while on the remaining hosts, the fructifications were typically acervular in nature. Considerable fluctuations in the structure of the fruiting bodies were observed.     

Interspecies migration and evolution of bacteriophages of the genus phiKZ: The purpose and criteria of the search for new phiKZ-like bacteriophages

Some properties of bacteriophages with large (200 kb and more) sequenced genomes have been compared. In contrast to other large bacteriophages from different families, bacteriophages active on pseudomonads of various species (phiKZ-like bacterio phages) have some common features, which suggests their phylogenetic relationship and independence of their evolution as a result of migration among bacteria of this family. Among such common features are the absence in the genomes of these phages of sites sensitive to endonuclease PstI, the absence of genes encoding DNA polymerases that are similar to the known enzymes of this type, possible dependence of replication of the phage genome on bacterial DNA polymerase, and a considerably larger average gene size as compared to that for other phages. Criteria are suggested for searching for novel phiKZ-like bacteriophages: the size of a phag e particle, production by bacteria infected with such phages of a large amount of highly viscous mucus. Taking into account the use of these bacteriophages in therapeutic preparations (due to a broad spectrum of lytic activity) and a poor knowledge of a majority of their gene products, it seems necessary to perform a more comprehensive genetic analysis of phages of this genus or their mutants for selecting those adequate for phage therapy.     

Morphology of some species of the genus Aulodrilus Bretscher

The external and internal morphology of Aulodrilus limnobius Bretscher, 1899, Aulodrilus pluriseta (Piguet, 1906) and Aulodrilus japonicus Yamaguchi, 1953, and morphology of the setal apparatus of Aulodrilus pigueti were studied on new material from Russia and compared with various literature data. Besides the peculiar wings on bifid setae, dominance of asexual reproduction is regarded as a primary synapomorphy of the genus and is accompanied by an anterior shift of the whole reproductive system and a tendency to doubling the gonads. Naidid-like cocoons, with a single egg, are another element of this reproductive mode. Similar characters seem to have arisen independently in several groups of Oligochaeta.     

Comparative study of temperate bacteriophages isolated from Yersinia

170 Yersinia strains belonging to various species were investigated for the presence of temperate bacteriophages. By induction with mitomycin C seven phages were isolated from Y. enterocolitica strains and one phage from a Y. frederiksenii strain. The phages were characterized on the basis of their morphology, host range, genome size, DNA homology, and protein composition. They belong to different phage families and reveal narrow to moderate wide host ranges. Some of the isolated phages were able to infect pathogenic as well as nonpathogenic strains of Y. enterocolitica. The genomes of all isolated phages were found to be composed of double stranded DNA ranging from about 40 to 60 kb. In addition to the analysed phages, a number of putative phages were induced in strains of Y. frederiksenii, Y. kristensenii, Y. intermedia, and Y. mollaretii. The putative phages were identified by isolation of phage DNA from cell free lysates but could not be propagated on indicator strains. Southern hybridization experiments revealed relationships between phages belonging to different families. Moreover, DNA homologies were observed between phages isolated from nonpathogenic Yersinia strains and a phage which was isolated from a pathogenic Y. enterocolitica serogroup O:3 strain.     

Comparative genomic analysis of 18 Pseudomonas aeruginosa bacteriophages

A genomic analysis of 18 P. aeruginosa phages, including nine newly sequenced DNA genomes, indicates a tremendous reservoir of proteome diversity, with 55% of open reading frames (ORFs) being novel. Comparative sequence analysis and ORF map organization revealed that most of the phages analyzed displayed little relationship to each other.