Open AccessAntifreeze protein activity in A rctic cryoconite bacteria
Author(s) -
Singh Purnima,
Hanada Yuichi,
Singh Shiv Mohan,
Tsuda Sakae
Publication year - 2014
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/1574-6968.12345
Subject(s) - antifreeze protein , bacteria , psychrophile , glacier , arctic , microbiology and biotechnology , pseudomonas putida , chemistry , pseudomonas , food science , biology , biochemistry , zoology , ecology , genetics , paleontology
Fourteen Arctic bacterial strains belonging to five genera, C ryobacterium , L eifsonia , P olaromonas , P seudomonas , and S ubtercola isolated from sediments found in cryoconite holes of Arctic glaciers, were subjected to screening for antifreeze proteins ( AFP s). Eight strains showed AFP activity, and six strains of four species were further characterized. P seudomonas ficuserectae exhibited a high thermal hysteresis ( TH ) activity. Ice recrystallization inhibition ( IRI ) activity was observed in most cultures at low protein concentration. Bacterial AFP s produced rounded shape of ice crystals that did not change their size and morphology within the TH window. Cry‐g ( P . ficuserectae ) failed to inhibit ice recrystallization, indicating that the IRI activity of the AFP s does not relate to the strength of TH activity. SDS ‐ PAGE analysis of the AFP s suggests their apparent molecular weights to be around 23 kDa. This study is significant as it screens several species of A rctic bacterial strains for AFP activity. So far, only one species of bacteria, P seudomonas putida , was reported from the A rctic to produce AFP s. N ‐terminal amino acid sequence analysis shows that the bacterial AFP s isolated belong to the AFP family IBP ‐1, which is known to have an important physiological role in the cold environment. AFP s of glacier cryoconite habitat have been discussed.