Cell Membrane Fatty Acid Composition of Chryseobacterium frigidisoli PB4T, Isolated from Antarctic Glacier Forefield Soils, in Response to Changing Temperature and pH Conditions

Abstract

Microorganisms in Antarctic glacier forefields are directly exposed to the hostile environment of their habitat characterized by extremely low temperatures and changing geochemical conditions. To survive under those stress conditions microorganisms adapt, among others, their cell membrane fatty acid inventory. However, only little is known about the adaptation potential of microorganisms from Antarctic soil environments. In this study, we examined the adaptation of the cell membrane polar lipid fatty acid inventory of Chryseobacterium frigidisoli PB4T in response to changing temperature (0°C to 20°C) and pH (5.5 to 8.5) regimes, because this new strain isolated from an Antarctic glacier forefield showed specific adaptation mechanisms during its detailed physiological characterization. Flavobacteriaceae including Chryseobacterium species occur frequently in extreme habitats such as ice-free oases in Antarctica. C. frigidisoli shows a complex restructuring of membrane derived fatty acids in response to different stress levels. Thus, from 20°C to 10°C a change from less iso-C15:0 to more iso-C17:1ω7 is observed. Below 10°C temperature adaptation is regulated by a constant increase of anteiso-FAs and decrease of iso-FAs. An anteiso- and bis-unsaturated fatty acid, anteiso-heptadeca-9,13-dienoic acid, shows a continuous increase with decreasing cultivation temperatures underlining the particular importance of this fatty acid for temperature adaptation in C. frigidisoli. Concerning adaptation to changing pH conditions, most of the dominant fatty acids reveal constant relative proportions around neutral pH (pH 6–8). Strong variations are mainly observed at the pH extremes (pH 5.5 and 8.5). At high pH short chain saturated iso- and anteiso-FAs increase while longer chain unsaturated iso- and anteiso-FAs decrease. At low pH the opposite trend is observed. The study shows a complex interplay of different membrane components and provides, therefore, deep insights into adaptation strategies of microorganisms from extreme habitats to changing environmental conditions.

Response of Methanogenic Archaea from Siberian Permafrost and Non-permafrost Environments to Simulated Mars-like Desiccation and the Presence of Perchlorate

“…Previous studies indicate that the permafrost and non-permafrost strains in this study have a different chemical composition in terms of aliphatic chain composition of lipids, aromatic amino acids, and carbohydrates among others (Serrano et al, 2015), which may be related to cold adaptive mechanisms and therefore a differential postfreezing recovery in the two groups. This is in accordance with a newly described fatty acid that regulates the temperature adaptation in a coldadapted bacterium isolated from an Antarctic ice-free oasis (Bajerski et al, 2017;Mangelsdorf et al, 2017). Furthermore, in our study, the freezing process might have activated a cold-shock response due to the transient overexpression of cold-shock proteins (CspA) that mediate cellular processes such as transcription, translation, protein folding, and the regulation of membrane fluidity (Phadtare, 2004).…”

Genotype and rhizobium inoculation modulate the assembly of soybean rhizobacterial communities

“…The unexpected increase in Chryseobacterium might be due to complex interactions between rhizobacteria and host plants or among microbes. Whatever mechanism of recruitment is employed, Chryseobacterium is known as an important plant associated bacteria with the ability to promote plant growth (Bajerski, Wagner, & Mangelsdorf, ; Cho et al, ; Dardanelle et al, ; Li & Zhu, ; Montero‐Calasanz et al, ). Consistent with this, Chryseobacterium isolated from soybean rhizosphere has been reported to stimulate soybean growth (Egamberdieva et al, ).…”

ATP Content and Cell Viability as Indicators for Cryostress Across the Diversity of Life

“…Cellular adaptations to temperature decline involve the differentiation of permanent cell forms such as spores or akinetes, changing the phospholipid fatty acid inventory to maintain the functionality of cellular membranes ( Bajerski et al, 2017 ), increasing the concentrations of enzymes ( Willem et al, 1999 ), expressing cold-adapted isoenzymes ( Hoyoux et al, 2001 ) or cold shock proteins stabilizing different cell constituents or changing gene expression ( Phadtare et al, 1999 ; Weber and Marahiel, 2003 ; Wilson and Nierhaus, 2004 ), or preventing intracellular ice nucleation through the accumulation of sugars, or cryoprotectants like polyols (glycerol, arabitol, trehalose, and mannitol), secondary metabolites, or anti-freezing proteins ( Duman and Olsen, 1993 ; Davies and Sykes, 1997 ; Sdebottom et al, 1997 ; Grant, 2004 ; Agrawal, 2009 ; De Maayer et al, 2014 ). Ice crystal formation can be inhibited and cellular proteins and membranes maintained in their native structure through the addition of glycerol or artificial cryoprotectants, particularly dimethyl sulfoxide (DMSO; Mazur, 1984 ).…”