Microscopic characterization of the bacterial cell envelope of Planococcus halocryophilus Or1 during subzero growth at −15 °C

Mykytczuk, N. C. S., Lawrence, J. R., Omelon, C. R., Southam, G. and Whyte, L. G. (2015) Microscopic characterization of the bacterial cell envelope of Planococcus halocryophilus Or1 during subzero growth at −15 °C. Polar Biology, 39 4: 701-712. doi:10.1007/s00300-015-1826-5


Author Mykytczuk, N. C. S.
Lawrence, J. R.
Omelon, C. R.
Southam, G.
Whyte, L. G.
Title Microscopic characterization of the bacterial cell envelope of Planococcus halocryophilus Or1 during subzero growth at −15 °C
Journal name Polar Biology   Check publisher's open access policy
ISSN 0722-4060
1432-2056
Publication date 2015-11-12
Year available 2015
Sub-type Article (original research)
DOI 10.1007/s00300-015-1826-5
Open Access Status Not Open Access
Volume 39
Issue 4
Start page 701
End page 712
Total pages 12
Place of publication Heidelberg, Germany
Publisher Springer
Language eng
Subject 1100 Agricultural and Biological Sciences
Abstract Microbial psychrophiles continue to expand our understanding of the adaptations required to thrive in cold environments. Planococcus halocryophilus strain Or1, a gram-positive, aerobic bacterial isolate from a Canadian high Arctic permafrost active layer, divides at temperatures as low as −15 °C and high salinity of 18 % NaCl. Initial studies of P. halocryophilus Or1 identified that under subzero conditions the cell envelope changed in appearance and composition. Our goal was to further analyze these features using scanning and transmission electron microscopy (SEM, TEM), confocal laser scanning microscopy (CLSM), and scanning transmission X-ray microscopy (STXM), which showed progressive changes in cell envelope composition during growth from optimal (25 °C) down to subzero (−15 °C) temperatures. S/TEM and CLSM illustrate that growth at −15 °C coincides with increasing hydrophobicity and distinct extracellular encrustations closely associated with the cell wall. STXM analyses resolved differences in cell composition with temperature, favoring higher amounts of protein and polysaccharide at higher temperatures compared to cells grown at −15 °C that were characterized by a cell envelope comprised of 20 % calcium carbonate, 50 % peptidoglycan, and 29 % choline. Analyses of the sequenced genome found the presence of several copies of carbonic anhydrase, a protein responsible for mineralization of calcium carbonate, and transcriptomic analyses revealed increased expression of a single copy at −15 °C along with the synthesis of peptidoglycan. The unique cell features of P. halocryophilus Or1 grown at −15 °C demonstrate unusual physiology that expands our understanding of psychrophilic adaptations and provides an example of microbially mediated calcium carbonate precipitation at subzero temperatures.
Keyword Arctic
Carbonate precipitation
Cellular adaptation
Psychrophile
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Earth Sciences Publications
Official 2016 Collection
 
Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 1 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 3 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Tue, 24 Nov 2015, 10:25:31 EST by System User on behalf of School of Earth Sciences