Khalil Ibrahim R, Irorere Victor U, Radecka Iza, Burns Alan T H, Kowalczuk Marek, Mason Jessica L, Khechara Martin P
Faculty of Science and Engineering, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1LY, UK.
Department of Biology, College of Science, Tikrit University, Tikrit PO Box 42, Iraq.
Materials (Basel). 2016 Jan 6;9(1):28. doi: 10.3390/ma9010028.
Poly-γ-glutamic acid (γ-PGA) is a naturally occurring polymer, which due to its biodegradable, non-toxic and non-immunogenic properties has been used successfully in the food, medical and wastewater industries. A major hurdle in bacteriophage application is the inability of phage to persist for extended periods in the environment due to their susceptibility to environmental factors such as temperature, sunlight, desiccation and irradiation. Thus, the aim of this study was to protect useful phage from the harmful effect of these environmental factors using the γ-PGA biodegradable polymer. In addition, the association between γ-PGA and phage was investigated. Formulated phage (with 1% γ-PGA) and non-formulated phage were exposed to 50 °C. A clear difference was noticed as viability of non-formulated phage was reduced to 21% at log 1.3 PFU/mL, while phage formulated with γ-PGA was 84% at log 5.2 PFU/mL after 24 h of exposure. In addition, formulated phage remained viable at log 2.5 PFU/mL even after 24 h of exposure at pH 3 solution. In contrast, non-formulated phages were totally inactivated after the same time of exposure. In addition, non-formulated phages when exposed to UV irradiation died within 10 min. In contrast also phages formulated with 1% γ-PGA had a viability of log 4.1 PFU/mL at the same exposure time. Microscopy showed a clear interaction between γ-PGA and phages. In conclusion, the results suggest that γ-PGA has an unique protective effect on phage particles.
聚γ-谷氨酸（γ-PGA）是一种天然存在的聚合物，由于其具有可生物降解、无毒和无免疫原性的特性，已成功应用于食品、医疗和废水处理行业。噬菌体应用中的一个主要障碍是，由于噬菌体易受温度、阳光、干燥和辐射等环境因素的影响，它们无法在环境中长时间存活。因此，本研究的目的是使用γ-PGA可生物降解聚合物来保护有用的噬菌体免受这些环境因素的有害影响。此外，还研究了γ-PGA与噬菌体之间的关联。将配制好的噬菌体（含1%γ-PGA）和未配制的噬菌体置于50°C环境中。可以明显看出差异，未配制的噬菌体在暴露24小时后，当浓度为log 1.3 PFU/mL时，存活率降至21%，而用γ-PGA配制的噬菌体在浓度为log 5.2 PFU/mL时，存活率为84%。此外，即使在pH 3的溶液中暴露24小时后，配制好的噬菌体在浓度为log 2.5 PFU/mL时仍具有活性。相比之下，未配制的噬菌体在相同暴露时间后完全失活。此外，未配制的噬菌体在紫外线照射下10分钟内就会死亡。同样，在相同暴露时间下，用1%γ-PGA配制的噬菌体存活率为log 4.1 PFU/mL。显微镜观察显示γ-PGA与噬菌体之间存在明显的相互作用。总之，结果表明γ-PGA对噬菌体颗粒具有独特的保护作用。
