Isolation,preservation,and biological characteristics analysis of a Listeria bacteriophage
The aim of our research was to obtain Listeria bacteriophages from food and related environments,and conduc-ted the analysis of the electron microscopic morphology,host range specificity,and biological characteristics of the purified phages.The double-layer agar method and the spot test were employed for the isolation and identification of a virulent Listeria phage named LMLPA5,with the isolated strain Listeria in-nocua Lin08 as the host.Phage morphology was observed by transmission electron microscope.The biological characteris-tics of the phage were assessed by determining their host range,optimal multiplicity of infection(MOI),one-step growth curve,and physicochemical stability.Additionally,the preservation efficacy of the phage at 4 ℃,-20 ℃,and-80 ℃ was explored.The phage LMLPA5 belongs to the family Myoviridae based on morphology,exhibiting clear and transparent plaques without halo surrounded.Strains of sever-al Listeria species and different serotypes strains of Listeria monocytogenes were susceptible to lysis by LMLPA5,indica-ting its broad-spectrum activity against Listeria monocytogenes.Optimal MOIs and single-step growth curve analyses revealed optimal MOIs of 0.1 and latent period of 10 minutes for LMLPA5,with average burst size at 95.2 PFU/cell.LMLPA5 was sensitive to high temperatures,and completely inactivated after exposure to 70 ℃ for 1 h,while the phage remained stable for over 32 hours ranging from 4 ℃ to 40 ℃.Within the pH range of 4 to 10,phage titer remained stable and completely inactiva-ted until 60 minutes of ultraviolet exposure.LMLPA5 displayed insensitivity to chloroform,confirming its non-enveloped phage morphology.The phages remained stable for over 8 months when store at 4 ℃ and-80 ℃.The biological characteristics and lysis capacity of phage LMLPA5 were elucidated in this study,which provide the basis for further application.
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维普
