Bacteriophages and their microbial hosts in terrestrial biotopes of Antarctica

Abstract

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.

Characterization of Biofilm Formation and Bacterial Resistance to Benzalkonium Chloride under Contrasting Cultivation Conditions

“…Regarding thermal conditions for the optimum growth and metabolic activity of P. putida, numerous comparative studies showed the highest bacterial activity in the temperature range from 25 to 30 • C, while more precise data are dependent on the cultivation conditions and experimental setup. In particular, the maximum nitrate removal activity of P. putida was found at 25 • C [30]; the phenol degradation by P. putida was nine times longer at 10 • C, compared to the corresponding values at 30 • C [31]; the production of arginine deiminase by P. putida was higher at 25 • C, compared with 37 • C [32]; and the optimum growth of P. putida isolated from Antarctic soils was at 16-28 • C [33]. The optimum temperature for the growth of S. epidermidis in culture was reported to be 37 • C [34].…”

Breaking the Ice: A Review of Phages in Polar Ecosystems

“…In recent years detailed genomic, structural, and infection kinetic characterization of phages have been undertaken from polar cryosphere environments, including soil from Antarctica [73,74] as well as sea ice from both the Arctic [75][76][77] and Antarctic [26,40] and a high Arctic lake [78]. These studies have shown that many cold-adapted phages isolated from sea ice featured siphovirus or myovirus morphotypes [76,79,75,40] and to a lesser degree short-tailed podophages [40,78] and filamentous phages, such as f327 isolated on Pseudoalteromonas [77].…”