scholarly journals Toxic oligopeptides in the cyanobacterium Planktothrix agardhii-dominated blooms and their effects on duckweed (Lemnaceae) development

Author(s):  
Barbara Pawlik-Skowrońska ◽  
Magdalena Toporowska ◽  
Hanna Mazur-Marzec

Cyanobacterial toxins are a global threat to aquatic organisms; however, they represent only one group of bioactive cyanobacterial metabolites. Very little is known about the effects of other cyanobacterial products (e.g., non-ribosomal oligopeptides) on freshwater macrophytes. Our experimental study revealed that the development of young duckweed Spirodela polyrhiza was inhibited by two aquatic extracts of cyanobacterial bloom samples predominated by Planktothrix agardhii and pure microcystin-LR (MC-LR). The extracts differed considerably in the content of MCs and other oligopeptides; they contained three or four MC variants and several other oligopeptides such as anabaenopeptins, aeruginosins, and planktocyclin. Their toxic effects on young plants (first frond area, root number, fresh biomass, and chlorophyll a content) were different. The more phytotoxic extract obtained from a higher cyanobacterial biomass contained a lower total MC concentration and different anabaenopeptin variants (e.g., anabaenopeptin H, G, HU892, and E/F) as well as planktocyclin, which were not present in another extract with a higher MC concentration. The obtained results suggested that P. agardhii oligopeptides other than MCs are harmful to young duckweeds and may exert even stronger toxic effects than MC-LR. The production of various variants of MCs together with other oligopeptides, and their toxicity to aquatic plants varied over seasons depending on the taxonomic composition of the cyanobacterial bloom. Germinated turions of S. polyrhiza can be used as a sensitive bioindicator of the cyanobacterial threat in aquatic ecosystems.

Author(s):  
P. Vered ◽  
V. Bityutsky ◽  
V. Kharchyshyn ◽  
M. Zlochevskiy

Generalized studies of the world scientific literature on the fate and risk assessment of exposure to silver nanoparticles (NPAg) both at the ecosystem level and at the organism level, as well as in the laboratory. It is emphasized that the toxic effect of silver nanoparticles, mechanisms and methods of action of NPAg on the body of aquatic organisms have been sufficiently studied in laboratory practice. However, there are some gaps and discrepancies between the results of laboratory tests and the study of real environmental consequences, and such inconsistencies hinder the development of appropriate effective measures to achieve environmental well-being. To bridge such gaps, this review summarizes how environmental conditions and the physicochemical properties of NPAg influence conflicting conclusions between laboratory and real-world environmental studies. It is emphasized that modern research on the pathways of entry, transformation and bioaccumulation of silver nanoparticles in natural aquatic ecosystems emphasizes the ability of such nanoparticles to penetrate intact physiological barriers, which is extremely dangerous. It is proved that silver nanoparticles have a toxic effect on microorganisms, macrophytes and aquatic organisms. The toxic effects of NPAg cover almost entire aquatic ecosystems. A study by a number of authors on the factors influencing the mobility, bioavailability, toxicity and environmental fate of Ag nanoparticles was analyzed to assess the environmental risk. In addition, this review systematically examines the various toxic effects of silver nanoparticles in the environment and compares these effects with the results obtained in laboratory practice, which is useful for assessing the environmental effects of such compounds. The dangerous chronic effects of low-concentration NPAg (μg/l) on natural aquatic ecosystems over a long period of time (months to several years) have been described in detail. In addition, the prospects for future studies of NPAg toxicity in natural freshwater environments are emphasized. Key words: nanoparticles of the medium (NPAg), ecosystem, laboratory wash, toxicity, aquatic organisms, ecological factors.


Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 698
Author(s):  
Sónia Gomes ◽  
Conceição Fernandes ◽  
Sandra Monteiro ◽  
Edna Cabecinha ◽  
Amílcar Teixeira ◽  
...  

The inappropriate use of antibiotics, one of the causes of the high incidence of antimicrobial-resistant bacteria isolated from aquatic ecosystems, represents a risk for aquatic organisms and the welfare of humans. This study aimed to determine the antimicrobial resistance rates among riverine Aeromonas spp., taken as representative of the autochthonous microbiota, to evaluate the level of antibacterial resistance in the Tua River (Douro basin). The prevalence and degree of antibiotic resistance was examined using motile aeromonads as a potential indicator of antimicrobial susceptibility for the aquatic environment. Water samples were collected from the middle sector of the river, which is most impacted area by several anthropogenic pressures. Water samples were plated on an Aeromonas-selective agar, with and without antibiotics. The activity of 19 antibiotics was studied against 30 isolates of Aeromonas spp. using the standard agar dilution susceptibility test. Antibiotic resistance rates were fosfomycin (FOS) 83.33%, nalidixic acid (NA) 60%, cefotaxime (CTX) 40%, gentamicin (CN) 26.67%, tobramycin (TOB) 26.67%, cotrimoxazole (SXT) 26.67%, chloramphenicol (C) 16.67%, and tetracycline (TE) 13.33%. Some of the nalidixic acid-resistant strains were susceptible to fluoroquinolones. Multiple resistance was also observed (83.33%). The environmental ubiquity, the natural susceptibility to antimicrobials and the zoonotic potential of Aeromonas spp. make them optimal candidates for studying antimicrobial resistance (AMR) in aquatic ecosystems. Aquatic environments may provide an ideal setting for the acquisition and dissemination of antibiotic resistance because anthropogenic activities frequently impact them. The potential risk of multi- and pan-resistant bacteria transmission between animals and humans should be considered in a “One Health—One World” concept.


Science ◽  
2021 ◽  
Vol 373 (6550) ◽  
pp. 61-65
Author(s):  
Matthew MacLeod ◽  
Hans Peter H. Arp ◽  
Mine B. Tekman ◽  
Annika Jahnke

Plastic pollution accumulating in an area of the environment is considered “poorly reversible” if natural mineralization processes occurring there are slow and engineered remediation solutions are improbable. Should negative outcomes in these areas arise as a consequence of plastic pollution, they will be practically irreversible. Potential impacts from poorly reversible plastic pollution include changes to carbon and nutrient cycles; habitat changes within soils, sediments, and aquatic ecosystems; co-occurring biological impacts on endangered or keystone species; ecotoxicity; and related societal impacts. The rational response to the global threat posed by accumulating and poorly reversible plastic pollution is to rapidly reduce plastic emissions through reductions in consumption of virgin plastic materials, along with internationally coordinated strategies for waste management.


2021 ◽  
Vol 10 (2) ◽  
Author(s):  
Robbie M. Martin ◽  
Michael Kausch ◽  
Kimarie Yap ◽  
John D. Wehr ◽  
Gregory L. Boyer ◽  
...  

ABSTRACT Raphidiopsis raciborskii and Planktothrix agardhii are filamentous, potentially toxin-producing cyanobacteria that form nuisance blooms in fresh waters. Here, we report high-quality metagenome-assembled genome sequences of R. raciborskii and P. agardhii collected from a bloom in Kissena Lake, New York.


OSEANA ◽  
2019 ◽  
Vol 42 (2) ◽  
pp. 12-22
Author(s):  
Triyoni Purbonegoro

FACTORS THAT AFFECTING THE TOXICITY OF POLLUTANTS TO AQUATIC ORGANISMS. There are a large number of pollutants in aquatic environment with various characteristics and factors that can modify and affect the toxicity of pollutants in this environment. The major factors affecting pollutant toxicity include physicochemical properties of pollutants, mode of exposure, time, environmental factors, and biological factors. Moreover, organisms in an aquatic ecosystem are seldom exposed to only single pollutant, and most cases the stress of pollution on aquatic ecosystems is related to the interaction and combined effects of many chemicals. The combined effects may be synergistic or antagonistic, depending on the pollutants and the physiological condition of the organism involved.


2018 ◽  
Vol 176 ◽  
pp. 01003
Author(s):  
Guangyu Zhao ◽  
Elin Malmqvist ◽  
Klas Rydhmer ◽  
Alfred Strand ◽  
Giuseppe Bianco ◽  
...  

We have developed an aquatic inelastic hyperspectral lidar with unrestricted focal-depth and enough sensitivity and spatio-temporal resolution to detect and resolve position and behavior of individual sub-millimeter aquatic organisms. We demonstrate ranging with monitoring of elastic echoes, water Raman signals and fluorescence from chlorophyllbearing phytoplankton and dye tagged organisms. The system is based on a blue CW diode laser and a Scheimpflug optical arrangement.


Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2265
Author(s):  
Peng Gu ◽  
Qi Li ◽  
Hao Zhang ◽  
Xin Luo ◽  
Weizhen Zhang ◽  
...  

Cyanobacterial blooms caused by eutrophication in Lake Taihu have led to ecological threats to freshwater ecosystems. A pilot scale experiment was implemented to investigate the relationship between cyanobacteria and other aquatic plants and animals in simulated eutrophic ecosystems under different phosphorus (P) regimes. The results of this study showed that cyanobacteria had two characteristics favorable for bloom formation in eutrophic ecosystems. One is the nutrient absorption. The presence of alkaline phosphatase was beneficial for algal cells in nutrition absorption under low P concentration. Cyanobacteria exhibited a stronger ability to absorb and store P compared to Vallisneria natans, which contributed to the fast growth of algal cells between 0.2 and 0.5 mg·L−1 of P (p < 0.05). However, P loads affected only the maximum biomass, but not the growth phases. The growth cycle of cyanobacteria remained unchanged and was not related to P concentration. P cycling indicated that 43.05–69.90% of the total P existed in the form of sediment, and P content of cyanobacteria showed the highest increase among the organisms. The other is the release of microcystin. Toxic microcystin-LR was released into the water, causing indirectly the growth inhibition of Carassius auratus and Bellamya quadrata and the reduction of microbial diversity. These findings are of importance in exploring the mechanism of cyanobacterial bloom formation and the nutrient management of eutrophic lakes.


Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3618
Author(s):  
Nemi Malhotra ◽  
Oliver B. Villaflores ◽  
Gilbert Audira ◽  
Petrus Siregar ◽  
Jiann-Shing Lee ◽  
...  

Graphene and its oxide are nanomaterials considered currently to be very promising because of their great potential applications in various industries. The exceptional physiochemical properties of graphene, particularly thermal conductivity, electron mobility, high surface area, and mechanical strength, promise development of novel or enhanced technologies in industries. The diverse applications of graphene and graphene oxide (GO) include energy storage, sensors, generators, light processing, electronics, and targeted drug delivery. However, the extensive use and exposure to graphene and GO might pose a great threat to living organisms and ultimately to human health. The toxicity data of graphene and GO is still insufficient to point out its side effects to different living organisms. Their accumulation in the aquatic environment might create complex problems in aquatic food chains and aquatic habitats leading to debilitating health effects in humans. The potential toxic effects of graphene and GO are not fully understood. However, they have been reported to cause agglomeration, long-term persistence, and toxic effects penetrating cell membrane and interacting with cellular components. In this review paper, we have primarily focused on the toxic effects of graphene and GO caused on aquatic invertebrates and fish (cell line and organisms). Here, we aim to point out the current understanding and knowledge gaps of graphene and GO toxicity.


Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2650
Author(s):  
Kiyoko Yokota ◽  
Marissa Mehlrose

Microplastics are an emerging environmental pollutant, whose global ubiquity is becoming increasingly evident. Conventional wastewater treatment does not completely remove them, and there are growing concerns about microplastics in source water and post-treatment drinking water. Microplastics have been reported to alter the development, physiology, and behavior of various aquatic organisms; however, limited knowledge exists on their effect on natural phytoplankton communities. Many studies also use uniformly spherical plastic beads, while most scrub particles in consumer products and secondary microplastics in the environment have various shapes and sizes. We tested the effects of two types of microplastics, 50 µm polystyrene (PS) calibration beads and polylactic acid (PLA) plastic body wash scrub particles, and one type of plant-derived body wash scrub particle on a natural phytoplankton assemblage through a 7-day incubation experiment in a temperate, mesotrophic lake. The calibration beads and the plant-derived particles generally did not alter the taxonomic composition of the phytoplankton in the mesocosms, while the PLA body wash microplastics eliminated cryptophytes (p < 0.001) and increased chrysophytes (p = 0.041). Our findings demonstrate differential effects of irregularly shaped PLA body wash microplastics vs. PS calibration beads on lake phytoplankters and empirically support potential bottom-up alteration of the aquatic food web by secondary microplastics.


2017 ◽  
Vol 6 (1) ◽  
pp. 8
Author(s):  
Ana Paula Justiniano Régo ◽  
Ederio Dino Bidoia ◽  
Cassiana Maria Reganhan-Coneglian

The ametryne herbicide is largely used on sugar cane plantation in Brazil. It is persistent in the environment and can be found in bodies of water, impacting the aquatic and terrestrial ecosystems. Generally, in crops are applied mixtures of herbicides in order to obtain a higher success in combating weeds. This study evaluated the toxicity only of ametryne herbicide, without mixture with other herbicides, in order to quantify only the degree of dangerousness. This work evaluated the toxicity of ametryne to one aquatic test organism (Daphnia similis) and two land test organism (Eruca sativa and Lactuca sativa). Immobility of D. similis was evaluated in the presence of ametryne. Influences of ametryne on seed germination and root growth of E. sativa and L. sativa were evaluated. Even at low concentrations (5.00 mg/L), ametryne caused toxic effects on the mobility of D. similis, and 0.25 g/L caused toxic effects on the seeds. Root growth and the percentage of inhibition showed greater sensitivity to ametryne compared with seed germination. Thus, ametryne resulted in toxic effects to the analyzed organisms, which may bring damage to both aquatic and terrestrial ecosystems.


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