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Virginie Gaget, Melody Lau, Barbara Sendall, Suzanne Froscio, Andrew R Humpage
The presence of toxigenic cyanobacteria (blue-green algae) in drinking water reservoirs poses a risk to human and animal health worldwide. Guidelines and health alert levels have been issued in the Australian Drinking Water Guidelines for three major toxins, which are therefore the subject of routine monitoring: microcystin, cylindrospermopsin and saxitoxin. While it is agreed that these toxic compounds should be monitored closely, the routine surveillance of these bioactive chemicals can be done in various ways and deciding which technique to use can therefore be challenging...
April 10, 2017: Water Research
Guofei Dai, Ningyan Peng, Jiayou Zhong, Ping Yang, Binchun Zou, Hui Chen, Qian Lou, Yuanyuan Fang, Wei Zhang
Metals can react with microcystin (MC), which is released from cyanobacterial blooms through various mechanisms; these reactions may mitigate the environmental and health risks of MCs but may also cause harm to aquatic ecosystems and humans. Several studies were conducted, including laboratory tests, ecological simulations, and a field investigation of Poyang Lake. The laboratory studies showed that Fe(3+), Cu(2+), and Pb(2+) stimulated MC photodegradation under high light intensity at the water-sediment interface, which reduced the MC accumulation in the sediment...
April 18, 2017: Environmental Pollution
Brett Greer, Ronald Maul, Katrina Campbell, Christopher T Elliott
Recently, there has been a rise in freshwater harmful algal blooms (HABs) globally, as well as increasing aquaculture practices. HABs can produce cyanotoxins, many of which are hepatotoxins. An ultra-performance liquid chromatography tandem mass spectrometry method was developed and validated for nine cyanotoxins across three classes including six microcystins, nodularin, cylindrospermopsin and anatoxin-a. The method was used to analyse free cyanotoxin(s) in muscle (n = 34), liver (n = 17) and egg (n = 9) tissue samples of 34 fish sourced from aquaculture farms in Southeast Asia...
April 20, 2017: Analytical and Bioanalytical Chemistry
Stanislav Melnik, A-C Neumann, R Karongo, S Dirndorfer, Martin Stübler, Verena Ibl, R Niessner, Dietmar Knopp, Eva Stoger
Antibody MC10E7 is one of a small number of monoclonal antibodies that bind specifically to [Arg4]-microcystins and it can be used to survey natural water sources and food samples for algal toxin contamination. However, the development of sensitive immunoassays in different test formats, particularly user-friendly tests for on-site analysis, requires a sensitive but also cost-effective antibody. The original version of MC10E7 was derived from a murine hybridoma, but we determined the sequence of the variable regions using the peptide mass-assisted cloning strategy and expressed a scFv (single-chain variable fragment) format of this antibody in yeast and a chimeric full size version in leaves of Nicotiana tabacum and N...
April 19, 2017: Plant Biotechnology Journal
Ling Zhang, Hui Zhang, Huan Zhang, Mikael Benson, Xiaodong Han, Dongmei Li
In the present study, we evaluated the toxic effects on the testis of the male offspring of MC-LR exposure during fetal and lactational periods. Pregnant females were distributed into two experimental groups: control group and MC-LR group which were exposed to 0 and 10 μg/L of MC-LR, respectively, through drinking water separately during fetal and lactational periods. At the age of 30 days after birth, the male offspring were euthanized. The body weight, testis index, and histomorphology change were observed and the global changes of piwi-interacting RNA (piRNA) expression were evaluated...
April 13, 2017: Food and Chemical Toxicology
Mathias Ahii Chia, Micheline Kézia Cordeiro-Araújo, Adriana Sturion Lorenzi, Maria do Carmo Bittencourt-Oliveira
Growing evidence suggests that some bioactive metabolites (e.g. cyanotoxins) produced by cyanobacteria have allelopathic potential, due to their inhibitory or stimulatory effects on competing species. Although a number of studies have shown that the cyanotoxin cylindrospermopsin (CYN) has variable effects on phytoplankton species, the impact of changing physicochemical conditions on its allelopathic potential is yet to be investigated. We investigated the physiological response of Microcystis aeruginosa (Cyanobacteria) and Acutodesmus acuminatus (Chlorophyta) to CYN under varying nitrogen and light conditions...
April 12, 2017: Ecotoxicology and Environmental Safety
Aloysio da S Ferrão-Filho, Daniel Abreu S de Silva, Taissa A de Oliveira, Valéria Freitas de Magalhães, Stephan Pflugmacher, Eduardo Mendes da Silva
Cyanobacteria produce different toxic compounds that affect animal life, among them hepatotoxins and neurotoxins. As cyanobacteria are able to produce a variety of toxic compounds at the same time, organisms may be, generally, subjected to their combined action. In the present study, we demonstrate the effects of single and combined hepatotoxic (microcystins) and neurotoxic (saxitoxins) producer cyanobacteria on cladocerans. Animals were exposed to two strains of cyanobacteria isolated from the same environment (Funil Reservoir, RJ), either in single or combined exposures...
April 14, 2017: Environmental Toxicology and Chemistry
Jieming Li, Renhui Li, Ji Li
Microcystins (MCs) are common cyanotoxins produced by harmful cyanobacterial blooms (HCBs) and severely threaten human and ecosystems health. Biodegradation is an efficient and sustainable biological strategy for MCs removal. Many novel findings in fundamental knowledge and application potential of MC-biodegradation have been documented. Little effort has devoted to summarize and comment recent research progress on MC-biodegradation, and discuss the research problems and gaps. This review deals with current research scenario in aerobic and anaerobic biodegradation for MCs...
April 10, 2017: Science of the Total Environment
Xiaodan Qin, Yuanxiu Wang, Bo Song, Xin Wang, Hua Ma, Jingli Yuan
A homogeneous time-resolved fluoroimmunoassay method for rapid and sensitive detection of microcystin-LR (MC-LR) in water samples was developed based on the interaction between water-soluble WS2 nanosheets and the conjugate of MC-LR with a luminescent Eu(3+) complex BHHBCB-Eu(3+) (BHHBCB: 1,2-bis[4'-(1″,1″,1″,2″,2″,3″,3″-heptafluoro-4″,6″-hexanedion-6″-yl)- benzyl]-4-chlorosulfobenzene). The large lateral dimensions and high surface areas of two-dimensional layered WS2 nanosheets enable easy adsorption of the MC-LR-BHHBCB-Eu(3+) conjugate, that lead to efficient quenching of the luminescence of Eu(3+) complex via energy transfer or electron transfer process...
April 27, 2017: Methods and Applications in Fluorescence
Stefan Altaner, Jonathan Puddick, Susanna A Wood, Daniel R Dietrich
Cyanobacteria can produce heptapetides called microcystins (MC) which are harmful to humans due to their ability to inhibit cellular protein phosphatases. Quantitation of these toxins can be hampered by their adsorption to common laboratory-ware during sample processing and analysis. Because of their structural diversity (>100 congeners) and different physico-chemical properties, they vary in their adsorption to surfaces. In this study, the adsorption of ten different MC congeners (encompassing non-arginated to doubly-arginated congeners) to common laboratory-ware was assessed using different solvent combinations...
April 6, 2017: Toxins
Laura García-Espín, Enrique A Cantoral, Antonia D Asencio, Marina Aboal
The ecological influence of cyanotoxins on aquatic biota remains unclear despite the numerous published references on toxicological and sanitary problems related with cyanophyte proliferation. The effects of microcystins and cyanophyte extracts on the photosynthesis of the algae that belong to two taxonomic groups, Rhodophyta and Bacillariophyta, were studied in an attempt to elucidate their role in the intraspecific competence and physiognomy of fluvial communities. The data showed that both cyanobacteria extracts and pure microcystin-LR affected the photosynthetic activity of all the tested organisms, diatoms (Fistulifera pelliculosa, Gomphonema parvulum, Nitzschia frustulum and Stephanodiscus minutulus) and red algae (Chroothece richteriana) at environmentally relevant concentrations...
April 5, 2017: Ecotoxicology
Andrej Meglič, Anja Pecman, Tinkara Rozina, Domen Leštan, Bojan Sedmak
Cyanobacterial blooms are global phenomena that can occur in calm and nutrient-rich (eutrophic) fresh and marine waters. Human exposure to cyanobacteria and their biologically active products is possible during water sports and various water activities, or by ingestion of contaminated water. Although the vast majority of harmful cyanobacterial products are confined to the interior of the cells, these are eventually released into the surrounding water following natural or artificially induced cell death. Electrochemical oxidation has been used here to damage cyanobacteria to halt their proliferation, and for microcystin degradation under in-vitro conditions...
March 2017: Journal of Environmental Sciences (China)
Laura Ceballos-Laita, Carlos Marcuello, Anabel Lostao, Laura Calvo-Begueria, Adrián Velazquez-Campoy, María Teresa Bes, María F Fillat, María-Luisa Peleato
The microcystin-producing Microcystis aeruginosa PCC 7806 and its close strain, the nonproducing Microcystis aeruginosa PCC 7005, grow similarly in the presence of 17 μM iron. Under severe iron deficient conditions (0.05 μM), the toxigenic strain grows slightly less than in iron-replete conditions, while the nonproducing microcystin strain is not able to grow. Isothermal titration calorimetry performed at cyanobacterial cytosol or meaningful environmental pHs values shows a microcystin-LR dissociaton constant for Fe(2+) and Fe(3+) of 2...
April 17, 2017: Environmental Science & Technology
P W Lehman, T Kurobe, S Lesmeister, D Baxa, A Tung, S J Teh
The increased frequency and intensity of drought with climate change may cause an increase in the magnitude and toxicity of freshwater cyanobacteria harmful algal blooms (CHABs), including Microcystis blooms, in San Francisco Estuary, California. As the fourth driest year on record in San Francisco Estuary, the 2014 drought provided an opportunity to directly test the impact of severe drought on cyanobacteria blooms in SFE. A field sampling program was conducted between July and December 2014 to sample a suite of physical, chemical, and biological variables at 10 stations in the freshwater and brackish reaches of the estuary...
March 2017: Harmful Algae
Maxine A D Mowe, Cristina Porojan, Feras Abbas, Simon M Mitrovic, Richard P Lim, Ambrose Furey, Darren C J Yeo
No abstract text is available yet for this article.
March 2017: Harmful Algae
Robert J Kieber, Lindsey M Hartrey, David Felix, Coleman Corzine, G Brooks Avery, Ralph N Mead, Stephen A Skrabal
A series of ten photolysis experiments was conducted with sediments exposed to Microcystis sp. blooms to determine if sunlight is capable of mobilizing the biotoxin microcystin-LR (MC-LR) into the water column. There was a net photorelease of MC-LR in irradiated suspensions in all cases relative to dark controls, ranging from 0.4 to 192μgL(-1)g(-1) into the dissolved phase. This should be viewed as a minimum estimate of photorelease due to concurrent photodegradation of dissolved toxin. Dissolved MC-LR concentrations in a sediment suspension increased linearly in the aqueous phase during a six-hour irradiation with simulated sunlight suggesting that longer exposure times produce greater quantities of MC-LR...
March 2017: Harmful Algae
Adam Crawford, Jon Holliday, Chester Merrick, John Brayan, Mark van Asten, Lee Bowling
An unusual bloom of Chrysosporum ovalisporum (basionym Aphanizomenon ovalisporum) occurred for the first time in the Murray River and distributary rivers in New South Wales, Australia, from mid-February to early June 2016. At its greatest extent, it contaminated a combined river length of ca. 2360 km. Chrysosporum ovalisporum usually comprised >99% of the total bloom biovolume at most locations sampled, which at times exceeded 40 mm(3) l(-1). The origins of the bloom were most likely reservoirs on the upper Murray River, with cyanobacterial-infested water released from them contaminating the river systems downstream...
April 2017: Environmental Monitoring and Assessment
Laiyan Wu, Songbo Wang, Min Tao, Ping Xie, Jun Chen
Tissue distribution of microcystin (MC)-LR-GSH, MC-LR-Cys and MC-LR of omnivorous fish in Lake Taihu was investigated. MC-LR and MC-LR-Cys were detected in liver, kidney and muscle. The concentration of MC-LR in liver and kidney was 0.052 μg g(-1) DW and 0.067 μg g(-1) DW, respectively. MC-LR-Cys appeared to be an important metabolite with average contents of 1.104 μg g(-1) DW and 0.724 μg g(-1) DW in liver and kidney, and the MC-LR-Cys/MC-LR ratio in liver and kidney reaching as high as 21.4 and 10.8. High MC-LR-Cys/MC-LR ratio and a significant correlation between MC-LR-Cys and MC-LR concentration in liver, suggest that liver is more active in detoxification of MC-LR by formation of MC-LR-Cys for omnivorous fish...
April 2017: Journal of Water and Health
Tsuyoshi Ikehara, Shihoko Nakashima, Junichi Nakashima, Tsubasa Kinoshita, Takeshi Yasumoto
Protein phosphatase 2A (PP2A) is an enzyme useful for detecting several natural toxins represented by okadaic acid and microcystins. We found that the production of the recombinant human PP2A catalytic subunit (rhPP2Ac) in High Five insect cells could markedly increase when the cells were cultured at 19 °C instead of 27 °C used under conventional conditions. The yield and purity of the enzyme increased four- and three-folds, respectively. The benefit of the altered culturing temperature was observed with the recombinant human protein phosphatase 2B but not 2Cα...
September 2016: Biotechnology Reports
Wansong Zong, Xiaoning Wang, Yonggang Du, Shuhan Zhang, Ying Zhang, Yue Teng
Glutathione (GSH) conjugation was an important pathway to regulate the toxicity of microcystins (MCs) targeted to protein phosphatases. To explore the specific molecular mechanism for GSH detoxification, two typical MC-GSHs (derived from MCLR and MCRR) were synthesized, prepared, and purified according to previous research. Then, the reduced inhibition effect for MC-GSHs on protein phosphatase 1 was verified by comparing with their original toxins. To further clarify the molecular mechanism for MC-GSHs detoxification, we evaluated the interactions between MCs/MC-GSHs and PP1 with the assistance of MOE molecule simulation...
2017: BioMed Research International
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