Carotenoids of an Antarctic psychrotolerant bacterium, Sphingobacterium antarcticus, and a mesophilic bacterium, Sphingobacterium multivorum

Abstract

The major carotenoid pigments of an Antarctic psychrotolerant bacterium, Sphingobacterium antarcticus, and a mesophilic bacterium, Sphingobacterium multivorum, were identified as zeaxanthin, beta-cryptoxanthin, and beta-carotene. Analysis was based on ultraviolet-visible spectroscopy, mass spectroscopy, and reversed-phase HPLC. Photoacoustic spectroscopy of intact bacterial cells revealed that the bulk of the pigments in S. antarcticus and S. multivorum was associated with the cell membrane. In vitro studies with synthetic membranes of phosphatidylcholine demonstrated that the major pigment was bound to the membranes and decreased their fluidity. The relative amounts of polar pigments were higher in cells grown at 5 degrees C than in cells grown at 25 degrees C. In the mesophilic strain, the synthesis of polar carotenoids was quantitatively less than that of the psychrotolerant strain.

Carotenoid Pigmentation in Antarctic Heterotrophic Bacteria as a Strategy to Withstand Environmental Stresses

“…Since these membrane modulations were reported for close relatives in both groups, one can speculate that additional factors contributed to the different response to freeze-thaw cycles. It has been demonstrated that lower cultivation temperatures promoted an increased carotenoid production in psychrotolerant bacteria (Jagannadham et al, 2000). Similarly, Yokoyama et al (1996) reported that bacteria growing under extreme conditions (e.g.…”

“…These strategies allow nutrient exchange and enzyme activity to occur, and most importantly prevent intracellular ice nucleation. Recent studies have suggested that pigments such as carotenoids may play a role in the modulation of membrane fluidity in bacteria (Jagannadham et al, 2000). Jagannadham et al (2000) speculated that when cells grow at low temperatures (5 uC), the unsaturated and branched-chain fatty acids increase the fluidity of the membrane, whereas polar carotenoids counterbalance this effect by stabilizing the membrane.…”

“…The high frequency of pigment production in recovered isolates from ice cores (Zhang et al, 2008), glaciers (Foght et al, 2004), or marine surface waters (Agogué et al, 2005) suggests that pigmentation plays a role in adaptation to cold environments. Moreover, carotenoid pigments may play a role in the modulation of membrane fluidity in bacteria growing under low temperature conditions (Jagannadham et al, 2000). Solar radiation is highly variable over a range of scales and wavelengths, and short-wavelength radiation can be more damaging to biological systems than longer wavelengths (Ekelund, 1992;Ross and Vincent, 1998;Cockell and Knowland, 1999).…”

Characterisation of yeast and filamentous fungi from Brøggerbreen glaciers, Svalbard

“…It is known that the modulation of membrane fluidity is brought about by changing the levels of polar and non-polar carotenoids (Jagannadham and others 2000). Thus, it seems that the pigments interacting with cell membranes increase its rigidity and enable cold-adaptation in cryoconite environment.…”

Role of Extracellular Polymeric Substances in the Surface Chemical Reactivity of Hymenobacter aerophilus , a Psychrotolerant Bacterium

“…Growth at low temperatures can lead to changes in membrane composition (4,23) that could affect the type and density of functional groups present on the cell surface. In addition to changes in fatty acid composition and carotenoid content, Corsaro et al (12) observed an increase in phosphorylation of lipooligosaccharides and exopolysaccharides with an increase in growth temperature for Pseudoalteromonas haloplanktis, an Antarctic bacterium.…”