Studying Cyanobacteria by Means of Fluorescence Methods: A Review

Abstract

Self-fluorescence is a powerful tool for investigation of living photosynthetic microorganisms. Since the physiological state of such microorganisms is closely related to the operation and activity of photosynthetic system; thus, any variations in spectroscopic properties of their self-fluorescence indicate the changes in their physiological state. Cyanobacteria (or blue green alga) are one of the most widespread photosynthetic organisms in nature, and the ecological aspect in their investigation is quite valuable. On the other hand, thousands of strains belonging to different cyanobacterial species are cultivated in biolaboratories all over the world for different biotechnological applications such as biofuel cells, food production, pharmaceuticals, and fertilizers. Thus, the novel noninvasive methods of their investigation are quite important for on-line monitoring of cyanobacterial cultures. In this chapter, several fluorescence techniques are presented for investigation of living cyanobacterial cells and cultures.

Enhancing hyperspectral imaging through macro and multi-modal capabilities

“…The SAB pigments are influenced by the nature of the substrate [30,31] as well as by the location and environmental conditions [32]. Since the physiological state of photosynthetic microorganisms is closely related to the activity of the photosynthetic system, any variation in their spectroscopic properties indicates changes in the microbial community physiology [29,33]. SAB sample on limestone was prepared according to the protocol reported by Villa et al [34] and detailed in supplementary information [35,36].…”

“…In fact, the observed emission is due to the fluorescence of the two photosystems (PS) PSI and PSII, with the peak around 710 nm being an indicator of the photosynthetic activity of the two PS [45,46] and the peak at 685 nm mainly corresponding to PSII and the Chlorophyll-a (Chl-a) subunit maximum emission [45,47]. The zones with a stronger red hue in the false RGB image and represented by the red spectrum in figure 3(G), disclose a strong emission shoulder at 710 nm, peculiar of intact cells and originated by the efficiency of the energy transfer between all components of the energy transfer chain, from the initially photoexcited phycobiliprotein to the reaction centre of photosystems PSI and PSII [33]. These regions also match the greenest areas in the reflectivity image.…”