Are Bacterio- and Phytoplankton Community Compositions Related in Lakes Differing in Their Cyanobacteria Contribution and Physico-Chemical Properties?

Bacterioplankton community composition has become the center of research attention in recent years. Bacteria associated with toxic cyanobacteria blooms have attracted considerable interest. However, little is known about the environmental factors driving the bacteria community, including the impact of invasive cyanobacteria. Therefore, our aim has been to determine the relationships between heterotrophic bacteria and phytoplankton community composition across 24 Polish lakes with different contributions of cyanobacteria including the invasive species Raphidiopsis raciborskii. This analysis revealed that cyanobacteria were present in 16 lakes, while R. raciborskii occurred in 14 lakes. Our results show that bacteria communities differed between lakes dominated by cyanobacteria and lakes with minor contributions of cyanobacteria but did not differ between lakes with R. raciborskii and other lakes. Physical factors, including water and Secchi depth, were the major drivers of bacteria and phytoplankton community composition. However, in lakes dominated by cyanobacteria, bacterial community composition was also influenced by biotic factors such as the amount of R. raciborskii, chlorophyll-a and total phytoplankton biomass. Thus, our study provides novel evidence on the influence of environmental factors and R. raciborskii on lake bacteria communities

On the occurrence and toxicity of Cylindrospermopsis raciborskii in Poland

Cylindrospermopsis raciborskii which belongs to the order of Nostocales has continuously been at the centre of interest of various research groups owing to its great ecological plasticity, wide distribution and potential to produce different metabolites known to be harmful for humans and animals. Over recent decades, Polish strains of C. raciborskii have also been studied with regard to these issues. The present paper is a brief review of the present state of knowledge respecting the occurrence and toxicity of this species with emphasis on Polish strains, and indicates potential directions for future research

Forensic botany: current state of knowledge and possible applications in investigative practice

Botanika sądowa jest nauką zajmującą się badaniem śladów biologicznych pochodzenia roślinnego pod kątem dowodowym wymiaru sprawiedliwości. W ramach botaniki sądowej największe zastosowanie mają: palinologia, anatomia roślin, diatomologia, ekologia roślin oraz biologia molekularna roślin. Jak wykazano, wiedza o roślinach może zostać wykorzystana do ustalenia powiązania między domniemanym sprawcą, ofiarą i miejscem zdarzenia. W praktyce śledczej metody botaniki sądowej były wykorzystywane do identyfikacji miejsc przetrzymywania porwanych oraz ukrycia zwłok, odróżnienia miejsca, w którym doszło do zdarzenia, od miejsca ostatecznego porzucenia ofiary, identyfikacji sprawcy przestępstwa, określenia przyczyny i czasu zgonu, śledzenia sieci dystrybucji narkotyków, wyjaśniania okoliczności przemytu roślin i zwierząt oraz zbrodni wojennych. Chociaż użyteczność botaniki sądowej w wyjaśnianiu okoliczności przestępstw została wielokrotnie potwierdzona, jej metody są w dużym stopniu niedoceniane i rzadko stosowane. W artykule prezentowane są: stan wiedzy w zakresie botaniki sądowej, charakterystyka poszczególnych jej dyscyplin, możliwości i ograniczenia zastosowania metod botaniki sądowej w praktyce śledczej oraz perspektywy jej rozwoju.Forensic botany is a science that studies biological traces of plant origin with regard to their practical usefulness as evidence used in judicial proceedings. Among the disciplines of forensic botany, the following have the widest application: palynology, plant anatomy, diatomology, plant ecology and plant molecular biology. It has been shown that the knowledge of plants can be used to determine the connections between the alleged perpetrator, victim and crime scenę. In practice, the methods of forensic botany have been used to identify locations where the hostages were held or the sites of concealment of a corpse, distinguish between the place of the incident and that where the victim was abandoned, identify the perpetrator, the cause and time of death, unravel drug distribution networks, clarify the circumstances of plant and animal smuggling as well as war crimes. Despite the fact that the suitability of forensic botany for determining the circumstances of criminal events has been repeatedly confirmed, this science remains largely underestimated and scarcely used. This article presents the current state of knowledge in the field of forensic botany, characterizes its specific disciplines, possibilities and limitations relating to the application of the methods of forensic botany in investigative practice as well as outlines the perspectives of its further development

Temporal variation in microcystin production by

Eutrophication of freshwater lakes has led to blooms formed by cyanobacteria often associated with toxins harmful to livestock and humans. Environmental conditions that favor toxin production during cyanobacterial blooms are, however, not well understood. Moreover, the ability to use cyanobacteria quantity to assess the level of threat associated with toxin production is a topic of discussion. The purpose for this study was to examine Planktothrix agardhii dynamics in a shallow, temperate hypertrophic lake and to determine the factors that affect microcystin production. In addition, the relationship between P. agardhii morphology and microcystin production was examined. The study spanned 2 years, and we documented a perennial P. agardhii bloom that contributed up to 99% of the total biomass. Intracellular microcystins were primarily detected throughout the study, with the highest concentration in October. Microcystin concentrations ranged from 3.4 to 71.2 μg.L−1, and they had a strong, positive correlation with P. agardhii biomass. In contrast, the levels of weight-specific microcystin were relatively stable throughout the entire study, ranging from 0.23 to 1.18 μg.mg−1. We also found that environmental factors, such as water temperature, phosphate level, ammonium nitrogen and transparency, were the most related to microcystin production. Furthermore, a significant relationship between filament morphology and toxin concentration suggested that there were different morphotypes within the toxic and non-toxic populations of P. agardhii. Our study showed that P. agardhii biomass and filament morphology may be useful characteristics for the identification of threats associated with cyanotoxins

Using genetic markers to monitor toxic cyanobacterial communities at the volcanic-origin lakes of Amatitlán and Atitlán, Guatemala

The lakes Amatitlán and Atitlán are two of the biggest freshwater ecosystems in Guatemala. Over 1000 years, lake Amatitlán has experienced cultural eutrophication, and within the last 50, toxigenic Microcystis spp are responsible for permanent cyanobacterial blooms. Also, eutrophication has increased in the oligotrophic lake Atitlán, and since 2010, with the appearance of Limnoraphis robusta blooms. Similar environmental conditions derived from their volcanic origin, could imply the accelerated deterioration of Atitlán, and thus, reliable detection methods should be implemented to better understand cyanotoxin production in both lakes. Here, we used molecular markers for the detection of genes involved in the synthesis of cyanotoxins in mentioned lakes. Sequencing analysis showed that in Amatitlán, Microcystis (16S rRNA) dominated and presented toxigenic genotypes with potential production of microcystins (mcyE) and anatoxins (anaC), and the concentration of microcystins reached 4.05 mg L-1 (HPLC analysis). In the case of Atitlán, the mcyE gene was detected for the first time with homology to Microcystis, during a bloom dominated by L. robusta. Our results evidence that the use of cyanotoxin gene markers can be incorporated in ongoing monitoring efforts for early detection of toxic cyanobacteria, and the importance to include prevention solutions focused on reducing nutrient loading

Photosynthetic efficiency in Polish and Australian Raphidiopsis raciborskii strains

Raphidiopsis raciborskii, as a potentially toxic, invasive cyanobacteria has attracted great attention. Worldwide distribution could have contributed to its phenotypic plasticity and even the formation of ecotypes adapted to the local environment. To determine mechanisms responsible for the omnipresence of R. raciborskii, photosynthetic efficiency in several strains differing in origin and toxicity has been investigated. Three non-toxic Polish strains and two toxic Australian strains were grown under standardized light and temperature conditions. Concentration of photosynthetic pigments, qualitative and quantitative analysis of carotenoid composition, and photosynthetic performance (chlorophyll fluorescence in vivo) were analysed. No significant differences between strains were observed in the photosystem II quantum efficiency (Fv/Fm), the photochemical (qP) and non-photochemical quenching (NPQ) and dark and light levels of plastoquinone reduction. Nonetheless, a positive correlation between Fv/Fm and overall NPQ was found. The phycocyanin concentration was negatively correlated with the carotenoid concentration in all five examined strains. Furthermore, in four strains roughly one third of pigments consisted of myxoxanthophylls. The ability to accumulate pigments involved both in light harvesting and photoprotection may contribute to the optimization of photosynthetic efficiency of investigated R. raciborskii strains in different environmental conditions. Documented parameters could not be ascribed to the difference in growth conditions, but could result from variations in their genetics

Cyanophage distribution across European lakes of the temperate-humid continental climate zone assessed using PCR-based genetic markers

Studies of the diversity and distribution of freshwater cyanophages are generally limited to the small geographical areas, in many cases including only one or few lakes. Data from dozens of various lakes distributed at a larger distance are necessary to understand their spatial distribution and sensitivity to biotic and abiotic factors. Thus, the objective of this study was to analyze the diversity and distribution of cyanophages within the infected cells using marker genes (psbA, nblA, and g91) in 21 Polish and Lithuanian lakes. Physicochemical factors that might be related to them were also analyzed. The results demonstrated that genetic markers representing cyanophages were observed in most lakes studied. The frequently detected gene was psbA with 88% of cyanophage-positive samples, while nblA and g91 were found in approximately 50% of lakes. The DNA sequence analyses for each gene demonstrated low variability between them, although the psbA sequences branched within the larger cluster of marine Synechoccocuss counterparts. The principal component analysis allowed to identify significant variation between the lakes that presented high and low cyanobacterial biomass. The lakes with high cyanobacterial biomass were further separated by country and the different diversity of cyanobacteria species, particularly Planktothrix agardhii, was dominant in the Polish lakes and Planktolyngbya limnetica in the Lithuanian lakes. The total phosphorous and the presence of cyanophage genes psbA and nblA were the most important factors that allowed differentiation for the Polish lakes, while the pH and the genes g91 and nblA for the Lithuanian lakes