Origin and release of cyanotoxins in surface water reservoirs

[eng] Cyanobacteria are prokaryotes and components of regular periphyton formation. Overall, there are around 2000 cyanobacterial species that live in various environments. Some cyanobacterial species are known to form blooms, which can cause harmful effects when blooms’ intensity is high. Abundant blooms can deplete oxygen causing hypoxic conditions that may result in the death of plants and animals. Another major issue associated with bloom-forming cyanobacteria is the production of bioactive secondary metabolites, some of which are known to be toxic. One of the main routes of human exposure to cyanobacterial toxins occurs through water, both drinking and recreational water use. There are two main drivers that favour cyanobacteria bloom: nutrient over-enrichment and on-going climate change. Nowadays, little quantitative information is available on temporal variations of cyanotoxins, including the European region. Establishing seasonal trends of cyanobacterial toxins will promote the development of effective water management strategies. Cyanotoxins can be divided into two main groups according to their targeted tissue/organ of toxicity: hepatotoxins and neurotoxins. Main cyanobacterial hepatotoxins are microcystins, nodularins, and cylindrospermopsin, while anatoxin-a, and saxitoxin are the main neurotoxins. Owning to posed toxicological risks by various cyanobacterial metabolites, guidelines values in drinking water have been introduced by several countries. What is more, the update of the WHO guideline has been recently finalized, and now it involves threshold values not only for microcystin variant, but also for cylindrospermopsin, anatoxin-a, and saxitoxins. The assessment of the occurrence and the risks of the exposure to cyanotoxins require robust, straightforward, and sensitive analytical methodologies for their identification and quantitation in the aquatic environment, and particularly in drinking water reservoirs. Besides, to perform extensive monitoring studies, these methods should be cost- effective and rapid. Beyond these cyanotoxins, cyanobacteria can produce a variety of other bioactive secondary metabolites, including cyanopeptides. These compounds belong to several classes including cyanopeptolins, anabaenopeptins, aeruginosins, aerucyclamides, and microginins. Some of these compounds are known to be co-produced together with other cyanobacterial toxins. Compounds from these classes have shown acute toxicity in planktonic grazers and are able to inhibit various enzymes. However, there is a knowledge gap in both their occurrence and posed toxicological risks. In the framework of this thesis, several points were addressed in order to fulfil the current gaps of the research in the area of occurrence of cyanobacterial toxins ant other metabolitesin surface water. Literature review on current analytical approaches for analysis of cyanotoxins and their seasonal variations in previously conducted studies in European region was carried out. Main analytical approaches were compared, what provided solid background for analytical method development. Based on available seasonal studies on cyanotoxins in different European climate zones, patterns for continental, Mediterranean, and oceanic climate zones were described. A method for the assessment of multiclass cyanotoxins in freshwater based on dual solid- phase extraction liquid chromatography coupled with high-resolution mass spectrometry was developed, optimised, and validated. The developed method showed high sensitivity, selectivity, and robustness. The application of an ultra-high pressure liquid chromatography column allowed fast separation, what makes this method more cost-effective. A targeted method was applied for the analysis of freshwater samples from Spain, Switzerland, and the United Kingdom. Several targeted cyanotoxins were identified and quantified. Additionally, mass spectrometry data acquired in high resolution provided an opportunity of posterior suspect screening, which revealed potential presence of another cyanopeptide – anabaenopeptin. Additionally, the targeted methodology was expanded for an application of suspect screening for a wide range of cyanopeptides. This method was applied for the analysis of raw drinking water from the United Kingdom. Suspect screening revealed co-occurrence of targeted compounds together with other cyanopeptides. The obtained results are the first to present concentrations of anabaenopeptins, cyanopeptolins, aeruginosins, and microginins, along with microcystins, in the reservoirs of the United Kingdom.[spa+ Las cianobacterias son procariotas y componentes de la formación regular de perifiton. En general, hay alrededor de 2000 especies de cianobacterias que viven en varios entornos. Se sabe que algunas especies de cianobacterias generan episodios de proliferación de toxinas, que pueden causar efectos nocivos cuando la intensidad de dicha proliferación es alta. Las proliferaciones abundantes pueden agotar el oxígeno y causar condiciones hipóxicas que pueden resultar en la muerte de plantas y animales. Otro problema importante asociado con las cianobacterias que conllevan dichas proliferaciones es la producción de metabolitos secundarios bioactivos, algunos de los cuales se sabe que son tóxicos. Una de las principales vías de exposición humana a las toxinas cianobacterianas se produce a través del agua, tanto las de consumo como las de uso recreativo. Hay dos factores principales que favorecen la proliferación de las cianobacterias: el enriquecimiento excesivo de nutrientes y el cambio climático continuo. En la actualidad, se dispone de poca información cuantitativa sobre las variaciones temporales de las cianotoxinas, incluida la región europea. Sin embargo, comprender las tendencias históricas es fundamental, ya que reduce la incertidumbre y proporciona una base sólida para la previsión de dichos episodios. El establecimiento de tendencias estacionales de toxinas cianobacterianas promoverá el desarrollo de estrategias efectivas para la gestión del agua. Las cianotoxinas se pueden dividir en dos grupos principales según su tejido / órgano de toxicidad objetivo: hepatotoxinas y neurotoxinas. Las principales hepatotoxinas cianobacterianas son microcistinas, nodularinas y cilindrospermopsina, mientras que la anatoxina-a y la saxitoxina son las principales neurotoxinas. Debido a los riesgos toxicológicos que plantean varios metabolitos de las cianobacterias, varios países han introducido valores de referencia en el agua potable. Es más, la actualización de la guía que la OMS ha finalizado recientemente incluye ahora valores umbral no solo para la variante de microcistina, sino también para cilindrospermopsina, anatoxina-a y saxitoxinas. La evaluación de la presencia y los riesgos de la exposición a las cianotoxinas requieren metodologías analíticas sólidas, sencillas y sensibles para su identificación y cuantificación en el medio acuático y, en particular, en los reservorios de agua potable. Además, para realizar estudios de seguimiento exhaustivos, estos métodos deben ser rentables y rápidos. Más allá de estas cianotoxinas, las cianobacterias pueden producir una variedad de otros metabolitos secundarios bioactivos, incluidos los cianopéptidos. Estos compuestos pertenecen a varias clases que incluyen cianopeptolinas, anabaenopeptinas, aeruginosinas, aeruciclamidas y microgininas. Se sabe que algunos de estos compuestos se coproducen junto con otras toxinas cianobacterianas. Los compuestos de estas clases han mostrado toxicidad aguda en herbívoros planctónicos y son capaces de inhibir varias enzimas. Sin embargo, existe una laguna de conocimiento tanto con respecto a su aparición como a los riesgos toxicológicos que plantean. En el marco de esta tesis, se abordaron varios puntos con el fin de cubrir los vacíos actuales de la investigación en el área de la presencia y distribución de toxinas cianobacterianas y otros metabolitos en aguas superficiales. Se llevó a cabo una revisión de la literatura sobre los enfoques analíticos actuales para el análisis de cianotoxinas y sus variaciones estacionales en estudios realizados anteriormente en la región europea. Se compararon los principales enfoques analíticos que proporcionaron una base sólida para el desarrollo de métodos analíticos. Sobre la base de los estudios estacionales disponibles sobre cianotoxinas en diferentes zonas climáticas europeas, se establecieron patrones para las zonas climáticas continentales, mediterráneas y oceánicas. Se desarrolló, optimizó y validó un método para la evaluación de cianotoxinas multiclase en agua dulce basado en cromatografía líquida de extracción en fase sólida dual combinada con espectrometría de masas de alta resolución. El método desarrollado una alta sensibilidad, selectividad y robustez. La utilización de una columna de cromatografía líquida de ultra alta presión permitió una separación rápida, lo que hace que este método sea más rentable. Se aplicó un método dirigido para el análisis de muestras de agua dulce de España, Suiza y Reino Unido. Se identificaron y cuantificaron varias cianotoxinas dirigidas. Además, los datos de espectrometría de masas adquiridos en alta resolución brindaron la oportunidad de realizar una detección posterior de sospechosos, lo que reveló la presencia potencial de otro cianopéptido: la anabaenopeptina. Además, el método dirigido se amplió para la detección de compuestos sospechosos en relación a una amplia gama de cianopéptidos. Este método se aplicó para el análisis de agua potable del Reino Unido. El cribado de sospechosos reveló la coexistencia de compuestos diana junto con otros cianopéptidos. Los resultados obtenidos son los primeros en presentar concentraciones de anabaenopeptinas, cianopeptolinas, aeruginosinas y microgininas, junto con microcistinas, en los reservorios de agua del Reino Unido

Ultra-trace analysis of cyanotoxins by liquid chromatography coupled to high-resolution mass spectrometry

The increasing frequency of episodes of harmful algal blooms of cyanobacterial origin is a risk for ecosystems and human health. The main human hazard may arise from drinking water supply and recreational water use. For this reason, efficient multiclass analytical methods are needed to assess the level of cyanotoxins in water reservoirs and tackle these problems. This work describes the development of a fast, sensitive and robust analytical method for multiclass cyanotoxins determination based on dual solid-phase extraction (SPE) procedure using a polymeric cartridge first Oasis HLB (Waters Corporation, USA), and second, a graphitized non-porous carbon cartridge, SupelcleanTM ENVI-CarbTM (Sigma-Aldrich, USA), followed by ultra-high performance liquid chromatography high-resolution mass spectrometry (SPE-UHPLC-HRMS). This method enabled the analysis of cylindrospermopsin, anatoxin-a, nodularin and seven microcystins (MC-LR, MC-RR, MC-YR, MC-LA, MC-LY, MC-LW, MC-LF). The method limits of detection (MLOD) of the validated approach were between 4 and 150 pg/L. The analytical method was applied to assess the presence of the selected toxins in 21 samples collected in 3 natural water reservoirs in the Ter River in Catalonia (NE of Spain) used to produce drinking water for Barcelona city (Spain)

Recent advances in detection of natural toxins in freshwater environments

Natural toxins can be classified according to their origin into biotoxins produced by microorganisms (fungal biotoxins or mycotoxins, algal and bacterial toxins), plant toxins or phytotoxins and animal toxins. Biotoxins are generated to protect organisms from external agents also in the act of predation. Among the different groups, bacterial toxins, mycotoxins and phytotoxins can produce damages in the aquatic environment including water reservoirs, with the consequent potential impact on human health. In the last few decades, a substantial labour of research has been carried out to obtain robust and sensitive analytical methods able to determine their occurrence in the environment. They range from the immunochemistry to analytical methods based on gas chromatography or liquid chromatography coupled to mass spectrometry analysers. In this article, the recent analytical methods for the analysis of biotoxins that can affect freshwater environments, drinking water reservoirs and supply are reviewed

Analysis, levels and seasonal variation of cyanotoxins in freshwater ecosystems

Nutrient over-enrichment in freshwater environments, together with the on-going climate change, favour the toxin-producing cyanobacteria bloom. Human health hazard may arise from drinking contaminated water. Additionally, cyanobacterial blooms affect other economic areas such as tourism, recreation, commercial fishery, water management and monitoring. Nowadays there is a scarcity of information on seasonal variations of cyanotoxins in various regions. Understanding of historical trends and seasonal variation patters is a foundation for forecasting and will help to develop effective water management strategies. This review gives an overview of cyanotoxins' analysis and levels in freshwater environments with particular emphasis on seasonal variations in Europe. Recent analytical approaches are discussed and the seasonal patterns for three major European climate zones (Mediterranean, continental, and Atlantic) were distinguished. Additionally, data from multi-year studies showed a tendency of increasing cyanotoxins' levels

COVID-19-related cardiac lesion: The questions of pathogenesis and diagnostics

Coronavirus infection is still a topic of interest in the medical community today. Among the heterogeneous clinical manifestations of this disease, lesions of cardiac structures often occur. They are mainly inflammatory in nature and can be acute or delayed. Aside from myocarditis, coronavirus infection can induce cardiac injuries, including acute coronary syndrome, thromboembolic events, heart failure, and heart rhythm disturbances. It is well known that the prognosis for patients with cardiac lesions significantly worsens; timely diagnosis and treatment initiation play an important role in preventing severe complications. This review presents the most recent literature data on the pathogenesis of cardiac lesions in COVID-19 patients and discusses the rational diagnosis of this pathology using modern techniques, such as laboratory, functional imaging (cardiac magnetic resonance is the most important of these), and invasive ones. It is now established that diagnosing myocarditis caused by coronavirus infection differs fundamentally from diagnosing other types of myocarditis. Furthermore, the main aspects of inflammatory heart lesions associated with COVID-19 vaccination are discussed, as this complication occurs more frequently than is commonly believed. It is often used as a rationale for refusing vaccination; however, this decision may severely affect the individual and the population

Cyanobacteria and their secondary metabolites in three freshwater reservoirs in the United Kingdom

Background Bloom-forming cyanobacteria occur globally in aquatic environments. They produce diverse bioactive metabolites, some of which are known to be toxic. The most studied cyanobacterial toxins are microcystins, anatoxin, and cylindrospermopsin, yet more than 2000 bioactive metabolites have been identified to date. Data on the occurrence of cyanopeptides other than microcystins in surface waters are sparse. Results We used a high-performance liquid chromatography-high-resolution mass spectrometry/tandem mass spectrometry (HPLC-HRMS/MS) method to analyse cyanotoxin and cyanopeptide profiles in raw drinking water collected from three freshwater reservoirs in the United Kingdom. A total of 8 cyanopeptides were identified and quantified using reference standards. A further 20 cyanopeptides were identified based on a suspect-screening procedure, with class-equivalent quantification. Samples from Ingbirchworth reservoir showed the highest total cyanopeptide concentrations, reaching 5.8, 61, and 0.8 µg/L in August, September, and October, respectively. Several classes of cyanopeptides were identified with anabaenopeptins, cyanopeptolins, and microcystins dominating in September with 37%, 36%, and 26%, respectively. Samples from Tophill Low reservoir reached 2.4 µg/L in September, but remained below 0.2 µg/L in other months. Samples from Embsay reservoir did not exceed 0.1 µg/L. At Ingbirchworth and Tophill Low, the maximum chlorophyll-a concentrations of 37 µg/L and 22 µg/L, respectively, and cyanobacterial count of 6 × 10 cells/mL were observed at, or a few days after, peak cyanopeptide concentrations. These values exceed the World Health Organization's guideline levels for relatively low probability of adverse health effects, which are defined as 10 µg/L chlorophyll-a and 2 × 10 cells/mL. Conclusions This data is the first to present concentrations of anabaenopeptins, cyanopeptolins, aeruginosins, and microginins, along with icrocystins, in U.K. reservoirs. A better understanding of those cyanopeptides that are abundant in drinking water reservoirs can inform future monitoring and studies on abatement efficiency during water treatment

INTERACTIONS BETWEEN ANXIETY LEVELS AND LIFE HABITS CHANGES IN GENERAL POPULATION DURING THE PANDEMIC LOCKDOWN: DECREASED PHYSICAL ACTIVITY, FALLING ASLEEP LATE AND INTERNET BROWSING ABOUT COVID-19 ARE RISK FACTORS FOR ANXIETY, WHEREAS SOCIAL MEDIA USE IS NOT

Background. The COVID-19 pandemic has substantially contributed to increased anxiety rates among the general population worldwide. Pandemic-related health anxiety and worries about getting COVID-19 can lead to generalized anxiety and anxiety somatization, which, together with insalubrious daily life habits, are risk factors of worsening somatic health in people with SARS-Cov-2 infection. Subjects and methods: The current study is a part of the COMET-G project (40 countries, n=55589; approved by the Ethics Committee of the Aristotle University of Thessaloniki), which represents an intermediate analysis of data collected anonymously via online links from a national sample of the Russian general population (n=9936, 31.09±12.16 y.o., 58.7% females) to estimate anxiety using STAI-S and self-reported changes in anxiety and life habits (physical activity, nutrition and weight, internet use, sleep) during the lockdown. All statistical calculations (descriptive statistics, between group comparisons using chi-square test, MANOVA, ANOVA, significant at p<0.05) were performed with IBM SPSS 27. Results: Overall STAI-S scores were 29+- 5.4, a subjective feeling of anxiety increase was reported in 40.3% of respondents (43.9% significantly > in females), worsening to clinical anxiety in 2.1% (2.4% > in females). 54.2% of respondents reported decreased physical activity, 33.1% gained weight, 72% used internet more often, 52.6% experienced worries related to the information about COVID-19 (56.8% > in females). 88% experienced worsened sleep quality, 69.2% stayed up until late, 23.2% took sleeping pills, and 31% had nightmares in which they felt trapped. To ANOVA, such life habits as reduced physical activity during the lockdown, increased time spent online, internet browsing about COVID-19, tendency to stay up late, use of sleeping pills and disturbing dreams with scenario of being trapped were significantly related to worsening of clinical anxiety. However, eating behaviour, weight changes, and social media use did not contribute to the clinical anxiety increase. Conclusions: Factors of decreased physical activity and sleep disturbances related to the lockdown, as well as excessive internet browsing for information about COVID-19, emerged as risk factors for increased anxiety, more notably in women than in men. Preventive measures should be targeted against relevant factors imparting anxiety in the vulnerable population