Explorative characterization and taxonomy‐aligned comparison of alterations in lipids and other biomolecules in Antarctic bacteria grown at different temperatures

Abstract

Temperature significantly impacts bacterial physiology, metabolism and cell chemistry. In this study, we analysed lipids and the total cellular biochemical profile of 74 fast‐growing Antarctic bacteria grown at different temperatures. Fatty acid diversity and temperature‐induced alterations aligned with bacterial classification—Gram‐groups, phylum, genus and species. Total lipid content, varied from 4% to 19% of cell dry weight, was genus‐ and species‐specific. Most bacteria increased lipid content at lower temperatures. The effect of temperature on the profile was complex and more species‐specific, while some common for all bacteria responses were recorded. Gram‐negative bacteria adjusted unsaturation and acyl chain length. Gram‐positive bacteria adjusted methyl branching (anteiso‐/iso‐), chain length and unsaturation. Fourier transform infrared spectroscopy analysis revealed Gram‐, genus‐ and species‐specific changes in the total cellular biochemical profile triggered by temperature fluctuations. The most significant temperature‐related alterations detected on all taxonomy levels were recorded for mixed region 1500–900 cm−1, specifically the band at 1083 cm−1 related to phosphodiester groups mainly from phospholipids (for Gram‐negative bacteria) and teichoic/lipoteichoic acids (for Gram‐positive bacteria). Some changes in protein region were detected for a few genera, while the lipid region remained relatively stable despite the temperature fluctuations.

Global biochemical profiling of fast-growing Antarctic bacteria isolated from meltwater ponds by high-throughput FTIR spectroscopy

“…The BHI broth, a rich and complex medium, might contain lipidic compounds affecting bacterial lipid profiles. However, FTIR spectroscopy analysis showed no lipid-related peaks as was shown in our previous findings [ 51 ]. The assignment of the main characteristic peaks and their misalignment for Gram-positive and Gram-negative bacteria are given in Table 2 .…”

“…The bacteria were isolated from water samples collected during the 5th Belarusian Antarctic Expedition in the austral summer season (January 2013) from the middle part of the water column of nine non-flowing temporary meltwater ponds (TMPs) located in rock baths of the Vecherny region of the Thala Hills oasis in the central part of Enderby Land (East Antarctica). Identification by 16S rRNA gene sequencing and comprehensive physiological characterization (enzymatic activity, optimal growth temperature, and antibiotic resistance, pigments characterization) of the isolates were previously reported [ 49 – 51 ].…”