Journal: Environmental Microbiology Reports

Article Title: Phenolic Iron Complexes Protect Glacier Ice Algae (Zygnematophyceae) Against Excessive UV and VIS Irradiation

doi: 10.1111/1758-2229.70149

Figure Lengend Snippet: Bright‐field images of two A. alaskanum cells from the glacier obtained in vivo (a, d), Raman spectra of putative phenols (g, i) and those of carotenoids (h, j) as the most common cellular components detected in the scanned areas (yellow rectangle/square) by micro‐Raman. The corresponding chemical maps show the intracellular distribution of putative phenols (b, e) and carotenoid pigments (c, f). Raman spectra (g–j) are shown normalised to their respective maxima, vertically shifted and with marked band positions for better orientation. Chemical maps show that phenols are located in the dark vacuoles (b, e) and carotenoids in chloroplasts (c, f), the latter distinguishable as green areas in the bright‐field images (a, d). Raman maps were acquired using the “green” excitation at 532 nm with two different powers: 1.0 mW in (a) and 0.1 mW in (d). The higher excitation power caused photobleaching of carotenoids but allowed to obtain a spectrum of phenols with a better signal‐to‐noise ratio. On the other hand, due to less photobleaching, one order of magnitude lower excitation power allowed to obtain a less noisy spectrum of carotenoids. In both cases, the respective spectra were identical, differing only in the signal‐to‐noise ratio.

Article Snippet: Two‐dimensional Raman maps were obtained with a WITec alpha300 RSA confocal Raman microscope (Oxford Instruments, WITec, Germany) with laser excitations at 532 nm, 647 nm, and 785 nm and various powers according to particular needs.

Techniques: In Vivo

Journal: Environmental Microbiology Reports

Article Title: Phenolic Iron Complexes Protect Glacier Ice Algae (Zygnematophyceae) Against Excessive UV and VIS Irradiation

doi: 10.1111/1758-2229.70149

Figure Lengend Snippet: Comparison of Raman spectra of the isolated main chromatographic peak from A. alaskanum field cells, purpurogallin carboxylic acid‐6‐ O ‐β‐d‐glucopyranoside (a), Fe(II)‐purpurogallin complexes (b) and pure purpurogallin (c). Drops of the peak isolated by LC/FC, the DMSO solutions of Fe(II)‐purpurogallin, and the purpurogallin reference were dried on the quartz slides prior to measurement. The arrows indicate putative markers of iron complexes. Excitation: 532 nm, power 2.0 mW (a) and 0.5 mW (b, c).

Article Snippet: Two‐dimensional Raman maps were obtained with a WITec alpha300 RSA confocal Raman microscope (Oxford Instruments, WITec, Germany) with laser excitations at 532 nm, 647 nm, and 785 nm and various powers according to particular needs.

Techniques: Comparison, Isolation

Journal: Environmental Microbiology Reports

Article Title: Phenolic Iron Complexes Protect Glacier Ice Algae (Zygnematophyceae) Against Excessive UV and VIS Irradiation

doi: 10.1111/1758-2229.70149

Figure Lengend Snippet: The Raman spectra of A. alaskanum , compared between dark vacuoles of field cells acquired in vivo (a), a dried sample prepared from the aqueous extract of stressed strain cells (depleted SFM without N and P; b) and visually unpigmented vacuoles of unstressed strain cells in vivo (grown in eSFM; c). The arrows indicate putative markers of iron complexes. Excitation: 532 nm, power 0.5 mW (a), 2.0 mW (b) and 1.0 mW (c).

Article Snippet: Two‐dimensional Raman maps were obtained with a WITec alpha300 RSA confocal Raman microscope (Oxford Instruments, WITec, Germany) with laser excitations at 532 nm, 647 nm, and 785 nm and various powers according to particular needs.

Techniques: In Vivo