Heavy Metals Effect on Cyanobacteria Synechocystis aquatilis Study Using Absorption, Fluorescence, Flow Cytometry, and Photothermal Measurements

Abstract

The toxic effect of six heavy metals on cyanobacteria Synechocystis aquatilis was studied by absorption, fluorescence, flow cytometry, and photothermal measurements. This study indicates that at the concentration used, the cyanobacteria are more sensitive to silver, copper, and mercury than to cadmium, lead, and zinc metals. Disregarding the decrease in the yields of the related radiative processes caused by photochemical processes and/or damage to phycobilisomes, no changes were detected in the efficiency of thermal deactivation processes within a few microseconds, which can indicate the lack of disturbances in the photosynthetic light reaction and the lack of damage to the photosystem caused by the heavy metal ions in the concentrations used. The results demonstrate that the relative values of fluorescence yield as well as promptly generated heat calculated for the metal-affected and unaffected (reference) bacteria are sensitive indicators of environmental pollution with heavy metal ions, whereas the complementary methods proposed could be used as a noninvasive and fast procedure for in vivo assessment of their toxicity.

Effects of heavy metals on Cyanothece sp. CCY 0110 growth, extracellular polymeric substances (EPS) production, ultrastructure and protein profiles

“…On the other hand, the O 2 evolution rate ceases as previously observed in other cyanobacteria [51,53]. Thus, it is possible that the increased levels of PSI and PSII proteins arise from the need to replace inactivated PS components.…”

The Complete Genome and Physiological Analysis of the Microbialite-Dwelling Agrococcus pavilionensis sp. nov; Reveals Genetic Promiscuity and Predicted Adaptations to Environmental Stress

“…The extracellular polymeric substances within cyanobacterial microbialite mats and biofilms bind heavy metals, then concentrate and remove them from the water column ( Arp et al, 1999 ). Cyanobacteria are the primary producers in microbialites ecosystems ( Dupraz et al, 2009 ), and are sensitive to heavy metals ( Dudkowiak et al, 2011 ). Any heterotroph that removes and detoxifies heavy metals as a byproduct of their metabolism would be rewarded by substrates for growth (e.g., carbon, nitrogen, phosphorus, and metals) by healthy cyanobacterial mats.…”

Studying Cyanobacteria by Means of Fluorescence Methods: A Review

“…Usually in order to detect any fluorescence, suspended cells require staining with organic dyes. In cyanobacteria, self-fluorescence of photopigments (chlorophylls and phycobilins) not only allows cells to be counted in a rapid manner but also enables a wide range of potential applications in ecological and biochemical studies, such as definition of biomass, distribution, and dynamics of phytoplankton [33,[107][108][109], discrimination and identification of algae species [110][111][112], and the investigation of the responses to contaminants [113][114][115][116]. It should be noted that the presence of these photopigments limits the possibility to stain cells with synthetic dyes as their excitation and emission spectra can greatly overlap.…”