Pilot assessment of cyanotoxins as potential risk factors for cancer in Bulgaria

Cyanoprokaryotes (=cyanobacteria, blue-green algae) are the most ancient oxygen-producing phototrophic microorganisms, spread all over the Globe, which form the important basis of different food chains in aquatic and terrestrial habitats. However, due to strong anthropogenic pressure during the last decades they are also responsible for causing nuisance algal blooms in different water bodies with deleterious effects on the mankind and ecosystems mainly due to production of toxic substances (cyanotoxins). Amongst them are the microcystins, nodularins, lyngbyatoxins and aplysiatoxins, known as tumor-promotors with increase of exposure routes through which humans and animals can be placed at risk (Meriluoto et al. 2017). However, the investigations on the relations between the occurrence and development of such diseases with the cyanotoxins and their producers are extremely scarce at a global scale (Yu and Chen 1994, Ueno et al. 1996, Fleming et al. 2002, Svircev et al. 2009, Drobac et al. 2011, Labine et al. 2015). During the last 15 years cyanoblooms and microcystins, nodularins and saxitoxins were detected in 16 different Bulgarian freshwater bodies, including some drinking-water reservoirs (Stoyneva-Gärtner et al. 2017). Amongst the detected toxins some new forms were recognized by their characteristic spectra (Pavlova 2007, Pavlova et al. 2007), and, more recently, a new potential producer of lyngbyatoxin was found in the Black Sea (Stoyneva et al. 2015). The poster shows a pilot assessment of the spread of cancer distribution and mortality vs. spread of cyanoblooms and cyanotoxins in Bulgaria. The pilot assessment is made on the basis of comparison of the general regions of spread of cyanotoxins in Bulgarian water bodies and toxin-producing cyanospecies during the period 2000-2017 (Stoyneva-Gärtner et al. 2017) with the spread of cancer in Bulgaria (e.g. Valerianova et al. 2015). The comparison shows general conformities between the spread of the "most dangerous" water bodies and main regions of cancer diseases in the country. The results obtained served as a basis for a new project proposal which aims at a deepening of the studies for improvement of prevention of cancer in the country

RED LIST OF BULGARIAN ALGAE. II. MICROALGAE.

The Red List presented in this paper is focused on Bulgarian non-marine microalgae which face a risk of extinction. The assignment to each IUCN Red List category is according to the seven specific criteria and their relative values in the new method for an evaluation of the threatened status of microalgae (STOYNEVA-GÄRTNER ET AL., this volume). The list contains 756 taxa (613 species, 82 varieties and 61 forms) from 7 divisions, classified in six IUCN categories and shows that threatened microalgae represent 14% the total algal biodiversity of Bulgaria

REVIEW OF THE CURRENT STATUS AND FUTURE PERSPECTIVES ON PSEUDOGYMNOASCUS DESTRUCTANS STUDIES WITH REFERENCE TO SPECIES FINDINGS IN BULGARIA

Emerging infectious diseases are a well-known threat to the wildlife and require complex research. There is a rapidly accumulating knowledge on the infectious disease of bats, named firstly White Nose Syndrome (WNS) and afterwards – White Nose Disease (WND), and its causative agent – the pathogenic fungus Pseudogymnoascus destructans. Although mass mortality of bats, known since a decade, is currently restricted to North America, the pathogen is of global concern as a potential threat to other hibernating bat populations. Therefore five years after the first comprehensive synthesis on the fungal ecology and relevant knowledge gaps (FOLEY ET AL. 2011), we decided to summarize the published information on the pathogen morphology, reproduction, ecological requirements, geographic distribution and systematic position. In addition, the present review compiles the available data on the affected bat species, mechanisms of WND, on the host response and on the effective treatment strategies with possible methods for fighting the pathogen to reduce the mortality in affected regions as well. Special attention is paid to the finding of the fungus in Bulgarian caves

Microcystis aeruginosa and M. wesenbergii Were the Primary Planktonic Microcystin Producers in Several Bulgarian Waterbodies (August 2019)

The rising interest in harmful cyanoprokaryote blooms promotes an increase of phycological and ecological research on potentially toxic species and their hazardous substances. The present study aimed to identify the main microcystin (MC) producers and their contribution to the phytoplankton of shallow waterbodies in Bulgaria, applying different methods. The sampling was performed in August 2019 in nine lakes and reservoirs, two of which (reservoirs Kriva Reka and Izvornik 2) were studied for the first time. The high contribution of cyanoprokaryotes to the total species composition and phytoplankton abundance was proved by light microscopic (LM) observations and HPLC analysis of marker pigments. The LM identification of potential MC-producers was supported by PCR amplification of mcyE and mcyB genes. The MCs amounts, detected by HPLC-DAD, varied by sites with a range from undetectable concentrations to 0.46 g L 1 with only one recorded variant, namely MC-LR. It was found only in the reservoirs Mandra and Durankulak, while toxigenic MC-strains were obtained by PCR from five more waterbodies. Both LM and PCR demonstrated that the MC-producers were Microcystis aeruginosa and M. wesenbergii, despite their occurrence in low amounts (<0.5–5% of the total biomass) when filamentous cyanoprokaryotes dominated.Peer reviewe

Review of cyanotoxicity studies based on cell cultures

Cyanotoxins (CTs) are a large and diverse group of toxins produced by the peculiar photosynthetic prokaryotes of the domain Cyanoprokaryota. Toxin-producing aquatic cyanoprokaryotes can develop in mass, causing “water blooms” or “cyanoblooms,” which may lead to environmental disaster—water poisoning, extinction of aquatic life, and even to human death. CT studies on single cells and cells in culture are an important stage of toxicological studies with increasing impact for their further use for scientific and clinical purposes, and for policies of environmental protection. The higher cost of animal use and continuous resistance to the use of animals for scientific and toxicological studies lead to a progressive increase of cell lines use. This review aims to present (1) the important results of the effects of CT on human and animal cell lines, (2) the methods and concentrations used to obtain these results, (3) the studied cell lines and their tissues of origin, and (4) the intracellular targets of CT. CTs reviewed are presented in alphabetical order as follows: aeruginosins, anatoxins, BMAA (β-N-methylamino-L-alanine), cylindrospermopsins, depsipeptides, lipopolysaccharides, lyngbyatoxins, microcystins, nodularins, cyanobacterial retinoids, and saxitoxins. The presence of all these data in a review allows in one look to advance the research on CT using cell cultures by facilitating the selection of the most appropriate methods, conditions, and cell lines for future toxicological, pharmacological, and physiological studies

Dataset for "Limnological changes in Lake Victoria since the mid‐20th century"

Dataset of light- (Secchi depth, vertical attenuation coefficient, euphotic depth), physico-chemical- (oxygen saturation, water temperature, specific conductivity, pH) and ecological-parameters (inorganic nutrients, particulate organic carbon, particulate nitrogen and phosphorus, Chlorophyll-a, phytoplankton biomass and composition) obtained from samples collected in Lake Victoria, a large lake in East Africa. Samples were collected in 2018-2019 in nearshore and offshore waters (Uganda), during three contrasting seasons: heavy rains (March), low rains (October) and dry (June), which corresponded to distinct water column mixing regimes, respectively, late-stratified, early-stratified and mixed regimes. Sampling was carried out during day light (between 7 am and 6 pm) in shallow nearshore sites (23, 15 and 16 stations for the mixed, early- and late-stratified seasons, respectively) to deeper offshore (7, 8 and 10) sites. At each sampling site we measured light parameters and we carried out vertical profiles (at a depth interval of 10 m, from the lake surface to the lake bottom) of physico-chemical and ecological parameters. In addition, while traveling between each sampling site we performed continuous measurements of physico-chemical parameters

Long‐term change of phytoplankton in Lake Kivu: The rise of the greens

Phytoplankton time‐series enable the observation of recurrent seasonal patterns on community composition, but drastic shifts in community structure are rarely observed, unless linked to anthropogenic impacts (e.g. changes in nutrient inputs). Here, we report a unique case of non‐seasonal, multiannual regime shift of phytoplankton community structure in Lake Kivu, East Africa, and explore the possible causes for such changes. 2. We recorded phytoplankton biomass every 2 weeks over a period of 12 years (from 2002 to 2015). Phytoplankton community previously dominated by cyanobacteria and diatoms changed considerably from 2012, with a conspicuous rise in the biomass of green algae (from 3 to 33% lake‐wide), and a decline of cryptophytes and cyanobacteria along with an increase in total chlorophyll a concentration. Concomitantly, we observed significant differences in the mixed layer depth between the two periods, resulting from changes in the thermal gradient. The euphotic zone depth was also reduced in 2012–2015, probably from the higher phytoplankton biomass. Moreover, mean particulate nitrogen and phosphorus increased as well as the particulate N:P ratio. 3. Desmids (Cosmarium laeve) now dominate the mixolimnion, probably due to atelomixis, observed in high‐frequency temperature measurements. We believe that decadal or multidecadal variability of climate on the Indian Ocean may be the reason for this regime shift in thermal stratification, with a strong impact in phytoplankton community structure. 4. In conclusion, our study demonstrates that tropical lakes may be subject to nonseasonal fluctuations that generate multiannual regime shifts. These regime shifts have probably never been reported previously because of the lack of long phytoplankton time‐series in low latitudes.Peer reviewe

Microcystis aeruginosa and M. wesenbergii Were the Primary Planktonic Microcystin Producers in Several Bulgarian Waterbodies (August 2019)

The rising interest in harmful cyanoprokaryote blooms promotes an increase of phycological and ecological research on potentially toxic species and their hazardous substances. The present study aimed to identify the main microcystin (MC) producers and their contribution to the phytoplankton of shallow waterbodies in Bulgaria, applying different methods. The sampling was performed in August 2019 in nine lakes and reservoirs, two of which (reservoirs Kriva Reka and Izvornik 2) were studied for the first time. The high contribution of cyanoprokaryotes to the total species composition and phytoplankton abundance was proved by light microscopic (LM) observations and HPLC analysis of marker pigments. The LM identification of potential MC-producers was supported by PCR amplification of mcyE and mcyB genes. The MCs amounts, detected by HPLC-DAD, varied by sites with a range from undetectable concentrations to 0.46 &micro;g L&minus;1 with only one recorded variant, namely MC-LR. It was found only in the reservoirs Mandra and Durankulak, while toxigenic MC-strains were obtained by PCR from five more waterbodies. Both LM and PCR demonstrated that the MC-producers were Microcystis aeruginosa and M. wesenbergii, despite their occurrence in low amounts (&lt;0.5&ndash;5% of the total biomass) when filamentous cyanoprokaryotes dominated