carotenoids are associated with several important biological functions as antenna pigments in photosynthesis or protectives against oxidative stress. Occasionally they were also discussed as part of the cold adaptation mechanism of bacteria. For two Staphylococcus xylosus strains we demonstrated an increased content of staphyloxanthin and other carotenoids after growth at 10 °C but no detectable carotenoids after grow at 30 °C. By in vivo measurements of generalized polarization and anisotropy with two different probes Laurdan and TMA-DPH we detected a strong increase in membrane order with a simultaneous increase in membrane fluidity at low temperatures accompanied by a broadening of the phase transition. Increased carotenoid concentration was also correlated with an increased resistance of the cells against freeze-thaw stress. In addition, the fatty acid profile showed a moderate adaptation to low temperature by increasing the portion of anteiso-branched fatty acids. The suppression of carotenoid synthesis abolished the effects observed and thus confirmed the causative function of the carotenoids in the modulation of membrane parameters. A differential transcriptome analysis demonstrated the upregulation of genes involved in carotenoid syntheses under low temperature growth conditions. The presented data suggests that upregulated synthesis of carotenoids is a constitutive component in the cold adaptation strategy of Staphylococcus xylosus and combined with modifications of the fatty acid profile constitute the adaptation to grow under low temperature conditions. Carotenoids represent a large group and comprise at least 800 described compounds 1,2 which are synthesized from isoprene units by phototrophic and chemoorganotrophic prokaryotes, plants, fungi, and algae 3. Most carotenoids consist of eight isoprene units resulting in a C40 backbone and usually display β-cyclisation 1,4. Only a few chemoorganotrophic bacteria are capable of producing C30, C45 or C50 carotenoids 4,5. Such a rare C30 carotenoid is produced by staphylococci 6,7. As lipophilic compounds, carotenoids are located in the cell membrane, but their orientation inside the membrane may vary depending on their chemical structure and on the thickness of the membrane 8,9. They perform important biological functions such as light harvesting as antenna pigments 10,11 , provide protection against oxidative stress 5,12 , provide protection from ultraviolet radiation 13,14 , and stabilization of pigment proteins 15. In addition to the functions mentioned above, the involvement of carotenoids in cold adaptation was suspected 16-18. We assumed that carotenoids might have a similar function in regulating membrane fluidity as sterols such as cholesterol or ergosterol in eukaryotic cells. They increase membrane order with concurrent maintenance of lateral lipid motility, which results in a liquid-ordered membrane state 19. Similar mechanisms were previously described for the bacterial sterol-like hopanoids 20,21 and isoprenoid quinones 22. In vitro studies wit...
Maltodextrin, modified starch, inulin, alginate, gum arabic, and combinations thereof were used as carrier agents for spray drying of carotenoid-rich goldenberry ( Physalis peruviana L.) juice and compared to cellobiose as an alternative carrier. Powders were analyzed with respect to particle size and morphology, yield, moisture content, cold water solubility, suspension stability, hygroscopicity, carotenoid encapsulation efficiency, and carotenoid retention during storage. A high initial carotenoid concentration after spray drying, a high encapsulation efficiency of 77.2%, and a slow carotenoid degradation kinetics favored the high carotenoid content of the cellobiose powder at the end of the storage. Cellobiose might protect the carotenoids from degradation processes by light exposure, high temperature, and oxygen due to a tighter particle crust and larger particle sizes. Therefore, cellobiose may be considered a potential carrier agent for the encapsulation of carotenoid-rich fruit juices.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.