Virus diversity in Antarctic biotopes remains understudied. Here, we describe bacteriophages isolated from terrestrial environments, provide data on their natural bacterial hosts and study phage-host systems. Six bacterial isolates (FCKU 539, FCKU 533, FCKU 534, FCKU 538, FCKU 542 and FCKU 540) were recovered and characterized. Isolated bacteria belonged to Pseudomonas genus (Pseudomonas sp., Pseudomonas fluorescens, Pseudomonas putida) with optimal cultivation temperatures of 16–28°C. These bacteria and previously described Bacillus subtilis FCKU 537 were used for analysing virus-host interactions. Six lytic phages were isolated and named P. fluorescens Antarctic virus 1 (PFAV1), P. fluorescens Antarctic virus 2 (PFAV2), P. fluorescens Antarctic virus 3 (PFAV3), P. putida Antarctic virus 4 (PPAV4), Pseudomonas sp. Antarctic virus 5 (PSAV5) and B. subtilis Antarctic virus 6 (BSAV6) in relation to their natural hosts. According to electron microscopy data, these phages belonged to Caudovirales order. Cross-inoculation demonstrated high specificity of all Antarctic phages, which infected only their initial hosts at moderate temperatures. PFAV2 and PFAV3 phages also infected laboratory Pseudomonas savastanoi and P. fluorescens isolates. This paper adds new data on the occurrence and diversity of viruses and their respective bacterial hosts in soil biotopes of Antarctica.

The present study was undertaken to determine the occurrence of virus particles in male accessory reproductive glands and to describe the changes in the affected tissues. Using electron microscopy techniques, it was possible to identify rod-shaped virus-like particles in accessory reproductive glands of male tsetse, Glossina morsitans morsitans Westwood. The viruses occurred intracellularly within the epithelial cells and in the lumen of the glands. Cell degeneration characterized by abundant clear vacuoles, membrane-bound vesicles, disorganization and elimination of cell organelles typified the infection. The inference, therefore, is that virus infection may be primarily responsible for the necrotic changes identified in the gland cells. It is suggested that the lesions caused in the gland epithelium by the infection would disturb the glandular cells and disrupt synthesis of the secretion. This may eventually destroy the male accessory reproductive glands leading to inability of the male flies to form spermatophores for transferring spermatozoa to the female tsetse. Lack of sperm transfer would consequently result in no egg fertilization.

The effects of infection by Trypanosoma brucei and DNA virus on the ultrastructure of the salivary gland cells in Glossina pallidipes Austen were investigated. Cytoplasm of uninfected cells contains a dense ribosomal population and rough endopiasmic reticulum, scattered Golgi areas and mitochondria. In infected ceils of salivary glands the ultrastructural integrity of the cytoplasm is profoundly changed due to cellular proliferation giving rise to a stratified epithelium and gland enlargement; cell degeneration characterized by formation of cytoplasmic vacuoles, chromatin margination, disorganization and elimination of cell organelles and gland hypertrophy. The virus particles are found in the nucleoplasm as well as the cytoplasm of cells. The ultrastructural evidence indicates that the virus are largely assembled in nuclei of cells and virions pass through the nuclear membrane. The trypanosomes are found within the degenerating cytoplasm and lumen of the cell.

The implications of the features observed in the infected cells are discussed, and possible suggestions are made regarding alteration of the metabolic functions due to infection.