Determination of Heavy Metal Content: Arsenic, Cadmium, Mercury, and Lead in Cyano-Phycocyanin Isolated from the Cyanobacterial Biomass.

Cyano-phycocyanin (C-PC) is a light-absorbing biliprotein found in cyanobacteria, commonly known as blue-green algae. Due to its antioxidative, anti-inflammatory, and anticancer properties, this protein is a promising substance in medicine and pharmaceuticals. However, cyanobacteria tend to bind heavy metals from the environment, making it necessary to ensure the safety of C-PC for the development of pharmaceutical products, with C-PC isolated from naturally collected cyanobacterial biomass. This study aimed to determine the content of the most toxic heavy metals, arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) in C-PC isolated from different cyanobacterial biomasses collected in the Kaunas Lagoon during 2019-2022, and compare them with the content of heavy metals in C-PC isolated from cultivated Spirulina platensis (S. platensis). Cyanobacteria of Aphanizomenon flos-aquae (A. flos-aquae) dominated the biomass collected in 2019, while the genus Microcystis dominated the biomasses collected in the years 2020 and 2022. Heavy metals were determined using inductively coupled plasma mass spectrometry (ICP-MS). ICP-MS analysis revealed higher levels of the most investigated heavy metals (Pb, Cd, and As) in C-PC isolated from the biomass with the dominant Microcystis spp. compared to C-PC isolated from the biomass with the predominant A. flos-aquae. Meanwhile, C-PC isolated from cultivated S. platensis exhibited lower concentrations of As and Pb than C-PC isolated from naturally collected cyanobacterial biomass.

Cyanobacteria and Their Metabolites in Mono- and Polidominant Shallow Eutrophic Temperate Lakes.

Monodominant (one species dominates) or polidominant (multiple species dominate) cyanobacterial blooms are pronounced in productive freshwater ecosystems and pose a potential threat to the biota due to the synthesis of toxins. Seasonal changes in cyanobacteria species and cyanometabolites composition were studied in two shallow temperate eutrophic lakes. Data on cyanobacteria biomass and diversity of dominant species in the lakes were combined with chemical and molecular analyses of fifteen potentially toxin-producing cyanobacteria species (248 isolates from the lakes). Anatoxin-a, saxitoxin, microcystins and other non-ribosomal peptides formed the diverse profiles in monodominant (Planktothrix agardhii) and polidominant (Aphanizomenon gracile, Limnothrix spp. and Planktolyngbya limnetica) lakes. However, the harmfulness of the blooms depended on the ability of the dominant species to synthesize cyanometabolites. It was confirmed that P. agardhii produced a greater amount and diverse range of MCs and other NRPs. In the polidominant lake, isolates of the co-dominant A. gracile, L. planctonica and P. limnetica synthesized no or only small amounts of cyanometabolites. In general, the profile of cyanometabolites was greater in cyanobacteria isolates than in environmental samples, indicating a high potential for toxic cyanobacteria bloom.

Cyano-Phycocyanin: Mechanisms of Action on Human Skin and Future Perspectives in Medicine.

Cyano-phycocyanin is one of the active pigments of the blue-green algae and is usually isolated from the filamentous cyanobacteria Arthrospira platensis Gomont (Spirulina). Due to its multiple physiological functions and non-toxicity, cyano-phycocyanin may be a potential substance for the topical treatment of various skin diseases. Considering that the conventional medicine faces drug resistance, insufficient efficacy and side effects, the plant origin compounds can act as an alternative option. Thus, the aim of this paper was to review the wound healing, antimicrobial, antioxidative, anti-inflammatory, antimelanogenic and anticancer properties and mechanisms of cyano-phycocyanin topical activities on human skin. Moreover, possible applications and biotechnological requirements for pharmaceutical forms of cyano-phycocyanin for the treatment of various skin diseases are discussed in this review.

Interplay of Nutrients, Temperature, and Competition of Native and Alien Cyanobacteria Species Growth and Cyanotoxin Production in Temperate Lakes.

Global warming and eutrophication contribute to formation of HABs and distribution of alien cyanobacteria northward. The current study assessed how alien to Europe Sphaerospermopsis aphanizomenoides and Chrysosporum bergii will co-occur with dominant native Planktothrix agardhii and Aphanizomenon gracile species under changing conditions in temperate freshwaters. The experiments were carried out to examine the effect of nutrients and temperature on the growth rate of cyanobacteria, production of cyanotoxins, and interspecies competition. The highest growth rate was determined for A. gracile (0.43 day-1) and S. aphanizomenoides (0.40 day-1) strains at all the tested nutrient concentrations (IP and IN were significant factors). S. aphanizomenoides adapted to the wide range of nutrient concentrations and temperature due to high species ecological plasticity; however, A. gracile was able to suppress its dominance under changing conditions. Regularity between tested variables and STX concentration in A. gracile was not found, but IP concentration negatively correlated with the amount of dmMC-RR and other non-ribosomal peptides (NRPs) in P. agardhii strains. The relative concentration of NRPs in nontoxic P. agardhii strain was up to 3-fold higher than in MC-producing strain. Our study indicated that nutrients, temperature, and species had significant effects on interspecies competition. A. gracile had a negative effect on biomass of both alien species and P. agardhii.

Effect of Increased Temperature on Native and Alien Nuisance Cyanobacteria from Temperate Lakes: An Experimental Approach.

In response to global warming, an increase in cyanobacterial blooms is expected. In this work, the response of two native species of Planktothrix agardhii and Aphanizomenon gracile, as well as the response of two species alien to Europe-Chrysosporum bergii and Sphaerospermopsis aphanizomenoides-to gradual temperature increase was tested. The northernmost point of alien species distribution in the European continent was recorded. The tested strains of native species were favoured at 20⁻28 °C. Alien species acted differently along temperature gradient and their growth rate was higher than native species. Temperature range of optimal growth rate for S. aphanizomenoides was similar to native species, while C. bergii was favoured at 26⁻30 °C but sensitive at 18⁻20 °C. Under all tested temperatures, non-toxic strains of the native cyanobacteria species prevailed over the toxic ones. In P. agardhii, the decrease in concentration of microcystins and other oligopeptides with the increasing temperature was related to higher growth rate. However, changes in saxitoxin concentration in A. gracile under different temperatures were not detected. Accommodating climate change perspectives, the current work showed a high necessity of further studies of temperature effect on distribution and toxicity of both native and alien cyanobacterial species.

Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins.

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.

Distribution of invasive Cylindrospermopsis raciborskii in the East-Central Europe is driven by climatic and local environmental variables.

Mechanisms behind expansion of an invasive cyanobacterium Cylindrospermopsis raciborskii have not been fully resolved, and different hypotheses, such as global warming, are suggested. In the East-Central Europe, it is widely occurring in western part of Poland but only in single locations in the East due to some limiting factors. Therefore, broad-scale phytoplankton survey including 117 randomly selected lakes in Poland and Lithuania was conducted. The results showed that C. raciborskii occurred widely in western part of Poland but was absent from other regions and Lithuania except one lake. The regions in which C. raciborskii was present had higher annual mean air temperature, higher maximum air temperature of the warmest month and higher minimum temperature of the coldest month, demonstrating that average air temperature, and indirectly, the duration of growing season might be more important factor driving C. raciborskii distribution than measured in situ water temperature. In turn, the presence of C. raciborskii in single localities may be more related to physiological adaptations of separated ecotype. Collectively, these results provide novel evidence on the influence of temperature on C. raciborskii distribution in East-European regions but also indicate high ecological plasticity of this species.