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Dariusz Dziga, Anna Maksylewicz, Magdalena Maroszek, Sylwia Marek
Under some conditions the growth of toxic cyanobacteria must be controlled by treatment with algicidal compounds. Hydrogen peroxide has been proposed as an efficient and relatively safe chemical which can remove cyanobacteria from the environment selectively, without affecting other microorganisms. However, the uncontrolled release of secondary metabolites, including toxins may occur after such a treatment. Our proposal presented in this paper concerns fast biodegradation of microcystin released after cell lysis induced by hydrogen peroxide...
March 15, 2018: Acta Biochimica Polonica
Juline M Walter, Fabyano A C Lopes, Mônica Lopes-Ferreira, Lívia M Vidal, Luciana Leomil, Fabiana Melo, Girlene S de Azevedo, Rossandra M S Oliveira, Alba J Medeiros, Adriana S O Melo, Carlos E De Rezende, Amilcar Tanuri, Fabiano L Thompson
Harmful cyanobacterial blooms have become increasingly common in freshwater ecosystems in recent decades, mainly due to eutrophication and climate change. Water becomes unreliable for human consumption. Here, we report a comprehensive study carried out to investigate the water quality of several Campina Grande reservoirs. Our approach included metagenomics, microbial abundance quantification, ELISA test for three cyanotoxins (microcystin, nodularins, and cylindrospermopsin), and in vivo ecotoxicological tests with zebrafish embryos...
2018: Frontiers in Microbiology
Trung Bui, Thanh-Son Dao, Truong-Giang Vo, Miquel Lürling
Warming climate is predicted to promote cyanobacterial blooms but the toxicity of cyanobacteria under global warming is less well studied. We tested the hypothesis that raising temperature may lead to increased growth rates but to decreased microcystin (MC) production in tropical Microcystis strains. To this end, six Microcystis strains were isolated from different water bodies in Southern Vietnam. They were grown in triplicate at 27 °C (low), 31 °C (medium), 35 °C (high) and 37 °C (extreme). Chlorophyll-a-, particle- and MC concentrations as well as dry-weights were determined...
March 14, 2018: Toxins
Jan Raska, Lucie Ctverackova, Aneta Dydowiczova, Iva Sovadinova, Ludek Blaha, Pavel Babica
HL1-hT1 cell line represents adult human liver stem cells (LSCs) immortalized with human telomerase reverse transcriptase. In this study, HL1-hT1 cells were found to express mesenchymal markers (vimentin, CD73, CD90/THY-1 and CD105) and an early hepatic endoderm marker FOXA2, while not expressing hepatic progenitor (HNF4A, LGR5, α-fetoprotein) or differentiated hepatocyte markers (albumin, transthyretin, connexin 32). In response to microcystin-LR (MC-LR), a time- and concentration-dependent formation of MC-positive protein bands in HL1-hT1 cells was observed...
March 10, 2018: Toxicology and Applied Pharmacology
Guotao Peng, Robbie Martin, Stephen Dearth, Xiaocun Sun, Gregory L Boyer, Shawn Campagna, Sijie Lin, Steven W Wilhelm
Freshwater cyanobacterial blooms are regularly formed by Microcystis spp., which are well-known producers of the hepatotoxin microcystin. The environmental factors that regulate microcystin synthesis remain unclear. We used reverse transcription-quantitative PCR (RT-qPCR), metabolomics, and toxin profiling (both by LC-MS) to measure the response of Microcystis aeruginosa NIES-843 to nitrogen (N) concentration, N chemistry (nitrate vs. urea), and a range of seasonally-relevant temperatures. Growth rates at lower temperatures were slower but resulted in increased cellular microcystin content (quota), and at these lower temperatures, N concentration had no effect on toxin production...
March 9, 2018: Environmental Science & Technology
Hong-Qiang Chen, Ji Zhao, Yan Li, Li-Xiong He, Yu-Jing Huang, Wei-Qun Shu, Jia Cao, Wen-Bin Liu, Jin-Yi Liu
Microcystin (MC) is a cyclic heptapeptide compound which could lead to the development of hepatocellular carcinoma. However, the underlying epigenetic regulation mechanism is largely unknown. In this study, microcystin-LR (L: lysine, R: arginine, MC-LR) was used to induce the malignant transformation of human hepatocyte L02 cell line. The profile of gene expression, microRNA (miRNA) and DNA methylation were detected through high-throughput sequencing. Compared with control group, the expression of 826 genes and 187 miRNAs changed significantly in MC-LR treated group...
March 5, 2018: Toxicology Letters
Shiqing Zhou, Yanghai Yu, Weiqiu Zhang, Xiaoyang Meng, Jinming Luo, Lin Deng, Zhou Shi, John C Crittenden
Advanced oxidation processes (AOPs) have been widely used for the destruction of organic contaminants in the aqueous phase. In this study, we introduce an AOP on activated peroxymonosulfate (PMS) by using ascorbic acid (H2A) to generate sulfate radicals (SO4•-). Sulfate radicals, hydroxyl radicals (HO•) and ascorbyl radicals (A•-) were found using electron spin resonance (ESR). But we found A•- is negligible in the degradation of microcystin-LR (MCLR) due to its low reactivity. We developed a first-principles kinetic model to simulate the MCLR degradation and predict the radical concentrations...
March 7, 2018: Environmental Science & Technology
Jing Wu, Yunlei Xianyu, Xiangfeng Wang, Dehua Hu, Zhitao Zhao, Ning Lu, Meng-Xia Xie, Hongtao Lei, Yiping Chen
In this work, we outline a signal amplification strategy using the coordination chemistry between Fe3+ and polyglutamic acid (PGA) for biosensing applications. The theoretical calculation based on density functional theory shows that PGA has a much higher binding affinity with Fe3+ than the other metal ions. Guided by this rationale, we prepare a PGA-mediated signal probe through conjugating PGA onto polystyrene (PS) nanoparticles to form a brush-like nanostructure for Fe3+ coordination. This PGA-PS brush (PPB) has a large loading capacity of Fe3+ with a number of 1...
March 7, 2018: Analytical Chemistry
Yu Sun, Xiaomu Yu, Mo Li, Jinghui Liu
Microcystin-LR (MC-LR) is the most common and toxic variant of microcystins. We hypothesize that p44/42 MAPK (ERK1/2) signal pathway is involved in MC-LR-induced cell adhesion alteration in a human liver cell line-HL7702. We identified that MC-LR constantly activated MEK1/2-ERK1/2 signal pathway for 24 h, 48 h and 72 h in vitro. MC-LR reduced hepatocytes adhesion efficiency. Furthermore, as the focal adhesion biomarker, hyperphosphorylation of paxillin (ser83) was induced by MC-LR, which can be blocked by ERK1/2 pathway inhibitor (U0126) and was enhanced after hepatocytes transfected with pCMV6-MAPK plasmid...
February 27, 2018: Chemosphere
Phodiso P Mashile, Anele Mpupa, Philiswa N Nomngongo
Microcystin LR (MC-LR) is a highly toxic compound and it is known for its adverse health effect on both humans and animals. Due to the ineffectiveness of conventional water treatments methods, for the past decades, researchers have been developing cost-effective ways of removing MC-LR from water bodies. This study reports the application of powdered activated carbon (PAC) obtained from the waste tyre for the removal of MC-LR. The choice of the adsorbent was chosen due to its attractive properties. The prepared tyre-based PAC was found to have the large surface area (1111 m2  g-1 )...
February 28, 2018: Toxicon: Official Journal of the International Society on Toxinology
Daniel Wiltsie, Astrid Schnetzer, Jason Green, Mark Vander Borgh, Elizabeth Fensin
The eutrophication of waterways has led to a rise in cyanobacterial, harmful algal blooms (CyanoHABs) worldwide. The deterioration of water quality due to excess algal biomass in lakes has been well documented (e.g., water clarity, hypoxic conditions), but health risks associated with cyanotoxins remain largely unexplored in the absence of toxin information. This study is the first to document the presence of dissolved microcystin, anatoxin-a, cylindrospermopsin, and β- N -methylamino-l-alanine in Jordan Lake, a major drinking water reservoir in North Carolina...
February 24, 2018: Toxins
Jie Xu, Yanxia Zhao, Baoyu Gao, Qian Zhao
The water eutrophication caused by cyanobacteria seasonally proliferates, which is a hot potato to be resolved for water treatment plants. This study firstly investigated coagulation performance of titanium tetrachloride (TiCl4 ) for Microcystis aeruginosa synthetic water treatment. Results show complete algal cell removal by TiCl4 coagulation without damage to cell membrane integrity even under harsh conditions; 60 mg/L TiCl4 was effective in removing the microcystins up to 85%. Furthermore, besides having stronger UV254 removal capability and the higher removal of fluorescent substances over Al- and Fe-based coagulants, TiCl4 coagulant required more compact coagulation and sedimentation tanks due to its significantly improved floc growth and sedimentation speed...
February 28, 2018: Environmental Science and Pollution Research International
Xiang Wu, Hao Wu, Saijun Wang, Yimian Wang, Rongfei Zhang, Xiaobin Hu, Jinyun Ye
Reducing the formation and growth of Microcystis colonies is an important prerequisite for the effective prevention and treatment of cyanobacterial blooms. Microcystis flos-aquae colonies was selected to investigate the potential of propionamide for use in controlling cyanobacterial blooms. Propionamide, one of the major allelochemicals in the root exudates of E. crassipes, was tested using different concentrations (0, 0.2, 1, and 2mgL-1 ) and dosing methods (one-time addition, semi-continuous addition, and continuous addition) to assess its effect on the growth of M...
February 24, 2018: Science of the Total Environment
Larisa Lvova, Carla Guanais Gonçalves, Luca Prodi, Marco Lombardo, Nelsi Zaccheroni, Emanuela Viaggiu, Roberta Congestri, Licia Guzzella, Fiorenzo Pozzoni, Corrado Di Natale, Roberto Paolesse
We present here the development of an all-solid-state optical sensor based on phenyl-substituted diaza-18-crown-6 hydroxyquinoline (DCHQ-Ph) for the indirect selective detection of microcystin-LR (MC-LR), reaching a very low detection limit of 0.05 μg L-1 , well below the World Health Organisation (WHO) guideline value (1 μg L-1 ) in potable water. We demonstrate the potential applicability of the developed method in fast and low-cost water toxicity estimation.
February 26, 2018: Chemical Communications: Chem Comm
Man Xiao, Ming Li, Colin S Reynolds
Morphological evolution from a unicellular to multicellular state provides greater opportunities for organisms to attain larger and more complex living forms. As the most common freshwater cyanobacterial genus, Microcystis is a unicellular microorganism, with high phenotypic plasticity, which forms colonies and blooms in lakes and reservoirs worldwide. We conducted a systematic review of field studies from the 1990s to 2017 where Microcystis was dominant. Microcystis was detected as the dominant genus in waterbodies from temperate to subtropical and tropical zones...
February 22, 2018: Biological Reviews of the Cambridge Philosophical Society
Thanh-Luu Pham, Motoo Utsumi
Cyanotoxins produced by toxic cyanobacteria pose a major, worldwide environmental threat to freshwater ecosystems. Microcystins (MCs) are considered to be the most hazardous groups. Indeed, some of the largest aquatic ecosystems on the earth are being contaminated with MCs. Questions have arisen regarding their transfer and bioaccumulation in natural environment. This review summarizes the present state of knowledge regarding toxic cyanobacteria and MCs, with a specific focus on their distribution in different components of aquatic ecosystems...
February 19, 2018: Journal of Environmental Management
Natália V Casquilho, Maria Diana Moreira-Gomes, Clarissa B Magalhães, Renata T Okuro, Victor Hugo Ortenzi, Emanuel K Feitosa-Lima, Lidia M Lima, Eliezer J Barreiro, Raquel M Soares, Sandra M F O Azevedo, Samuel S Valença, Rodrigo S Fortunato, Alysson Roncally Carvalho, Walter A Zin
Microcystins-LR (MC-LR) is a cyanotoxin produced by cyanobacteria. We evaluated the antioxidant potential of LASSBio-596 (LB-596, inhibitor of phosphodiesterases 4 and 5), per os, and biochemical markers involved in lung and liver injury induced by exposure to sublethal dose of MC-LR. Fifty male Swiss mice received an intraperitoneal injection of 60 μL of saline (CTRL group, n = 20) or a sublethal dose of MC-LR (40 μg/kg, TOX group, n = 20). After 6 h the animals received either saline (TOX and CTRL groups) or LB-596 (50 mg/kg, TOX + LASS group, n = 10) by gavage...
February 15, 2018: Toxicon: Official Journal of the International Society on Toxinology
Jason Dexter, Dariusz Dziga, Jing Lv, Junqi Zhu, Wojciech Strzalka, Anna Maksylewicz, Magdalena Maroszek, Sylwia Marek, Pengcheng Fu
In this report, we establish proof-of-principle demonstrating for the first time genetic engineering of a photoautotrophic microorganism for bioremediation of naturally occurring cyanotoxins. In model cyanobacterium Synechocystis sp. PCC 6803 we have heterologously expressed Sphingopyxis sp. USTB-05 microcystinase (MlrA) bearing a 23 amino acid N-terminus secretion peptide from native Synechocystis sp. PCC 6803 PilA (sll1694). The resultant whole cell biocatalyst displayed about 3 times higher activity against microcystin-LR compared to a native MlrA host (Sphingomonas sp...
February 14, 2018: Environmental Pollution
Akin Karci, Elizabeth M Wurtzler, Armah A de la Cruz, David Wendell, Dionysios D Dionysiou
Transformation products and toxicity patterns of microcystin-LR (MC-LR), a common cyanotoxin in freshwaters, during degradation by solar photo-Fenton process were studied in the absence and presence of two major water components, namely fulvic acid and alkalinity. The transformation products m/z 795, 835, 515/1030 and 532 can be formed through attack of OH on the conjugated carbon double bonds of Adda. Transformation products with m/z 1010, 966 and 513 can be generated through the attack of OH on the methoxy group of Adda...
January 2, 2018: Journal of Hazardous Materials
Yujiao Wang, Yanqiu Cao, Hongmei Li, Aijun Gong, Jintao Han, Zhen Qian, Wenran Chao
Microcystins (MCs) is a kind of hepatotoxin, which is the secondary metabolite of cyanobacteria. Bi 2 O 2 CO 3 (BOC) is a kind of cheap and nontoxic semiconductor material. BOC was synthetized by solvothermal method and then microcystin-LR (MC-LR) and microcystin-RR (MC-RR) were removed by BOC, through adsorption and photocatalytic degradation. When the dosage of BOC is 6 g/L, the MC-LR and MC-RR in the natural water sample can be completely adsorbed in 30 min and then after 12 h irradiation, MC-LR and MC-RR were photocatalytically degraded by BOC...
February 14, 2018: Environmental Science and Pollution Research International
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