Escherichia coli infekuojančių bakteriofagų charakterizavimas /

• Main Author: Morkutė, Agnė
• Format: Bachelor Thesis
• Language: Lithuanian; English
• Published: Institutional Repository of Vilnius University 2019
• Subjects: Arctic
• Online Access: https://repository.vu.lt/VU:ELABAETD193352681&prefLang=en_US

Characterisation of Bacteriophages Infecting Escherichia coli The objective of this thesis was to characterise bacteriophages Se2D, J10D, SLe5, ErLe7, GudLiu, ShP6, SlP7, ErVi20, JsA10 ir ShCh6 infecting Escherichia coli. To achieve this, a series of different experiments and tasks were undertaken in order to define the optimal temperature range for bacteriophage development, to determine their host specificity, also to classify the bacteriophages based on virion morphology, and to identify which receptors may be involved in host recognition and phage adsorption. All bacteriophages have been found to show highest efficiency of plating in a temperature range of 22-37°C, a significant decrease in efficiency of plating has been observed at temperatures 10°C and 42°C. The host range appears to be rather narrow in the case of all phages analysed, lysis has not been observed on the lawns of Arctic Express, DH10B, and XL1-blue E. coli bacterial strains. For all phages tested, an experiment involving a number of single-gene deletion mutants revealed that the outer membrane protein FhuA may play a crucial role in host recognition and infection. Transmission electron microscopy (TEM) has shown that all bacteriophages belong to the order Caudovirales (tailed bacteriophages). Phages Se2D, J10D, SLe5, ErLe7, GudLiu, ShP6, SlP7, ErVi20 and ShCh6 belong to the family Siphoviridae, and share similar characteristics of an icosahedral head and a long non-contractile tail. Bacteriophage JsA10 is a myovirus with a contractile tail and a slightly elongated head.