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Jiajia Lv, Sen Zhao, Shijia Wu, Zhouping Wang
Water safety is one of the most pervasive problems afflicting people throughout the world. Microcystin-LR (MC-LR), a representative toxin released by cyanobacteria, poses an increasing and serious threat to water safety. In order to develop facile, specific and sensitive detection methods for MC-LR, we fabricated an ultrasensitive fluorescence aptasensor using the enhanced fluorescence of UCNP and the effective quenching ability, high affinity toward single strand DNA (ssDNA) of MoS2 (termed as FAUM). This assay specifically determined MC-LR in the linear range of 0...
October 4, 2016: Biosensors & Bioelectronics
Benjamin L Woolbright, C David Williams, Hongmin Ni, Sean Kumer, Timothy Schmitt, Bartholomew Kane, Hartmut Jaeschke
Microcystins are a group of toxins produced by freshwater cyanobacteria. Uptake of microcystin-leucine arginine (MC-LR) by organic anion transporting polypeptide 1B2 in hepatocytes results in inhibition of protein phosphatase 1A and 2A, and subsequent cell death. Studies performed in primary rat hepatocytes demonstrate prototypical apoptosis after MC-LR exposure; however, no study has directly tested whether apoptosis is critically involved in vivo in the mouse, or in human hepatocytes. MC-LR (120 μg/kg) was administered to C57BL/6J mice and cell death was evaluated by alanine aminotransferase (ALT) release, caspase-3 activity in the liver, and histology...
November 23, 2016: Toxicon: Official Journal of the International Society on Toxinology
A Zastepa, Z E Taranu, L E Kimpe, J M Blais, I Gregory-Eaves, R W Zurawell, F R Pick
Based on an analysis of sediment cores from Baptiste Lake (Alberta, Canada), we quantified century-scale trends in cyanobacteria and cyanotoxins, and identified possible drivers of toxigenic cyanobacteria. We measured concentrations of microcystins and pigments preserved in the sediment as proxies of toxigenic cyanobacteria and phytoplankton communities, respectively, while fossil diatom assemblages were used to infer past nutrient concentrations. Microcystins were detected in older sediments (ca. 1800s), pre-dating any significant alteration to the watershed...
November 22, 2016: Science of the Total Environment
M G Paulino, D Tavares, F Bieczynski, P G Pedrão, N E S Souza, M M Sakuragui, C M Luquet, A P Terezan, J B Fernandes, A Giani, M N Fernandes
Radiocystis fernandoi R28 strain is a cyanobacterium which produces mostly the RR and YR microcystin variants (MC-RR and MC-YR, respectively). The effects of crude extract of the R. fernandoi strain R28 were evaluated on the protein phosphatases and on the structure and ultrastructure of the liver of the Neotropical fish, Hoplias malabaricus, after acute and subchronic exposure. Concomitantly, the accumulation of the majority of MCs was determined in the liver and muscle. The fish were exposed to 120.60 MC-RR+MC-LR kg-fish(-1) (=100μg MC-LReq kg-fish(-1)) for 12 and 96h (one single dose, acute exposure) and 30days (one similar dose every 72h, subchronic exposure)...
November 17, 2016: Aquatic Toxicology
Shenshen Zhang, Chuanrui Liu, Yang Li, Mustapha U Imam, Hui Huang, Haohao Liu, Yongjuan Xin, Huizhen Zhang
Microcystin-LR (MC-LR) is a ubiquitous peptide that exhibits strong reproductive toxicity, although the mechanistic basis for such toxicity remains largely unknown. The present study was conducted to investigate the mechanisms underlying the adverse effects of exposure to MC-LR in Chinese hamster ovary (CHO) cells. The results showed that MC-LR inhibited the in vitro proliferation of CHO cells significantly, with an IC50 of 10 μM. Moreover, MC-LR-treated CHO cells revealed strong induction of cell cycle arrest and apoptosis...
2016: Frontiers in Physiology
Ying Liu, Shi Chen, Jian Zhang, Xuewen Li, Baoyu Gao
Antibiotics are normally regarded as safe to aquatic ecosystems when their contamination concentrations are lower than the toxic threshold. This study observed the hazard of ciprofloxacin, sulfamethoxazole and their binary mixture to the aquatic environment at environmentally relevant concentrations lower than the toxic threshold, due to the stimulation on the bloom of Microcystis aeruginosa. The enhanced growth of M. aeruginosa, coupled with elevated photosynthesis activity, was exerted by 50 - 200 ng/L of ciprofloxacin, 100 - 200 ng/L of sulfamethoxazole and 20 - 100 ng/L of the binary antibiotic mixture...
November 19, 2016: Molecular Ecology
Klara Bulc Rozman, Damijana Mojca Jurič, Dušan Šuput
Microcystins (MCs) comprise a group of cyanobacterial toxins with hepatotoxic, nephrotoxic and, possibly, neurotoxic activity in mammals. In order to understand the development of their neurotoxicity we investigated the toxic effects of MC variants, MC-LR, MC-LW and MC-LF, in astrocytes that play a central role in maintaining brain homeostasis. 24h exposure of cultured rat cortical astrocytes to MCs revealed dose-dependent toxicity of MC-LF and MC-LW, but not of MC-LR, observed by significant reduction in cell number, declined viability monitored by MTT test and an increased percentage of apoptotic cells, confirmed by Annexin-V labelling...
November 15, 2016: Toxicology Letters
Senlin Shao, Yijing Feng, Huarong Yu, Jiangyun Li, Guibai Li, Heng Liang
Gravity-driven membrane (GDM) filtration is a promising decentralized drinking water treatment process. To improve the performance of GDM system, a thin layer of adsorbent was pre-deposited on the membrane surface prior to filtration (adsorbent-laden GDM system). The tested adsorbents include powdered activated carbon (PAC) and anion exchange resin (AER), and an unmodified GDM system and a SiO2-laden GDM system were used as controls. In the adsorbent-laden GDM systems, the adsorption of the PAC and AER increased the removal efficiency of natural organic matter by 7...
November 2, 2016: Water Research
Susanna A Wood, Marcia Y Maier, Jonathan Puddick, Xavier Pochon, Anastasija Zaiko, Daniel R Dietrich, David P Hamilton
Cyanobacteria are commonly associated with eutrophic lakes, where they often form blooms and produce toxins. However they are a ubiquitous component of phytoplankton in lakes of widely varying trophic status. We hypothesised that cyanobacterial diversity would vary among lakes of differing trophic status, but that the relative importance of geographic and hydromorphological characteristics driving these patterns would differ across trophic groups. DNA from 143 New Zealand lakes that spanned a range of geographic, hydromorphological and trophic gradients was analysed using automated rRNA intergenic spacer analysis (ARISA) and screened for genes involved in cyanotoxin production...
November 16, 2016: FEMS Microbiology Ecology
Yan Ren, Mengli Yang, Meng Chen, Qiangqiang Zhu, Lihua Zhou, Wei Qin, Ting Wang
Increasing evidences suggest that microcystins, a kind of toxic metabolites, produced by cyanobacteria in contaminated water may contribute to the aggravation of the human colorectal carcinoma. Our previous study showed that microcystin-LR (MC-LR) exposure caused significant invasion and migration of colorectal cancer cells. However, the roles of MC-LR in regulating epithelial-mesenchymal transition (EMT) in colorectal cancer cells remain unknown. In our study, we observed that MC-LR treatment decreased epithelial marker E-cadherin expression and up-regulated the levels of mesenchymal markers Vimentin and Snail in colorectal cancer cells...
November 14, 2016: Toxicology Letters
Anton Liaimer, John B Jensen, Elke Dittmann
Liverwort Blasia pusilla L. recruits soil nitrogen-fixing cyanobacteria of genus Nostoc as symbiotic partners. In this work we compared Nostoc community composition inside the plants and in the soil around them from two distant locations in Northern Norway. STRR fingerprinting and 16S rDNA phylogeny reconstruction showed a remarkable local diversity among isolates assigned to several Nostoc clades. An extensive web of negative allelopathic interactions was recorded at an agricultural site, but not at the undisturbed natural site...
2016: Frontiers in Microbiology
Mawethu P Bilibana, Avril R Williams, Candice Rassie, Christopher E Sunday, Hlamulo Makelane, Lindsay Wilson, Nomaphelo Ntshongontshi, Abongile N Jijana, Milua Masikini, Priscilla G L Baker, Emmanuel I Iwuoha
A sensitive and reagentless electrochemical aptatoxisensor was developed on cobalt (II) salicylaldiimine metallodendrimer (SDD-Co(II)) doped with electro-synthesized silver nanoparticles (AgNPs) for microcystin-LR (L, l-leucine; R, l-arginine), or MC-LR, detection in the nanomolar range. The GCE|SDD-Co(II)|AgNPs aptatoxisensor was fabricated with 5' thiolated aptamer through self-assembly on the modified surface of the glassy carbon electrode (GCE) and the electronic response was measured using cyclic voltammetry (CV)...
November 11, 2016: Sensors
Haruyo Yamaguchi, Shigekatsu Suzuki, Tomoharu Sano, Yuuhiko Tanabe, Nobuyoshi Nakajima, Masanobu Kawachi
Microcystis aeruginosa is a well-known bloom-forming cyanobacterium. We newly sequenced the whole genome of M. aeruginosa NIES-98, which is a non-microcystin-producing strain isolated from Lake Kasumigaura, Japan. The genome contains approximately 5.0 Mbp, with an average G+C content of 42.41% and 5,140 predicted protein-coding genes.
November 10, 2016: Genome Announcements
María Ángeles Lezcano, Jesús Morón-López, Ramsy Agha, Isabel López-Heras, Leonor Nozal, Antonio Quesada, Rehab El-Shehawy
The microcystin biodegradation potential of a natural bacterial community coexisting with a toxic cyanobacterial bloom was investigated in a water reservoir from central Spain. The biodegradation capacity was confirmed in all samples during the bloom and an increase of mlrA gene copies was found with increasing microcystin concentrations. Among the 24 microcystin degrading strains isolated from the bacterial community, only 28% showed presence of mlrA gene, strongly supporting the existence and abundance of alternative microcystin degradation pathways in nature...
November 3, 2016: Toxins
Zidong Liu, Dapeng Li, Qing Hu, Rong Tang, Li Li
Microcystin-LR (MC-LR) has the potential to disturb thyroid hormone homeostasis. However, the effects of MC-LR at environmentally relevant concentrations on the thyroid system in adult fish are still unclear. In this study, adult zebrafish were exposed to 0, 1, 5, and 25 μg/L MC-LR for 7, 14, 21, and 28 days. Whole-body thyroid hormones (THs) levels and thyroid follicle histology were used to assess thyroid function. The transcription of corticotropin-releasing hormone (crh), thyroid-stimulating hormone (tsh), transthyretin (ttr), thyroid hormone receptors (trs) genes, and the activities of iodothyronine deiodinases (IDs) were investigated to study the process of TH metabolism disruption...
December 15, 2016: Toxicon: Official Journal of the International Society on Toxinology
Qin Qiao, Séverine Le Manach, Hélène Huet, Evelyne Duvernois-Berthet, Soraya Chaouch, Charlotte Duval, Benoit Sotton, Loïc Ponger, Arul Marie, Lucrèce Mathéron, Sarah Lennon, Gérard Bolbach, Chakib Djediat, Cécile Bernard, Marc Edery, Benjamin Marie
Cyanobacterial blooms threaten human health as well as the population of other living organisms in the aquatic environment, particularly due to the production of natural toxic components, the cyanotoxin. So far, the most studied cyanotoxins are microcystins (MCs). In this study, the hepatic alterations at histological, proteome and transcriptome levels were evaluated in female and male medaka fish chronically exposed to 1 and 5 μg L(-1) microcystin-LR (MC-LR) and to the extract of MC-producing Microcystis aeruginosa PCC 7820 (5 μg L(-1) of equivalent MC-LR) by balneation for 28 days, aiming at enhancing our understanding of the potential reproductive toxicity of cyanotoxins in aquatic vertebrate models...
October 26, 2016: Environmental Pollution
Ana L Pereira, Joana Azevedo, Vitor Vasconcelos
Blooms of harmful cyanobacteria that synthesize cyanotoxins are increasing worldwide. Agronomic plants can uptake these cyanotoxins and given that plants are ultimately ingested by humans, this represents a public health problem. In this research, parsley and coriander grown in soil and watered through 7 days with crude extracts containing microcystins (MCs) or cylindrospermopsin (CYN) in 0.1-1 μg mL(-1) concentration range were evaluated concerning their biomass, biochemical parameters and uptake of cyanotoxins...
November 2, 2016: Environmental Science and Pollution Research International
Ankita Srivastava, So-Ra Ko, Chi-Yong Ahn, Hee-Mock Oh, Alok Kumar Ravi, Ravi Kumar Asthana
Roles of nutrients and other environmental variables in development of cyanobacterial bloom and its toxicity are complex and not well understood. We have monitored the photoautotrophic growth, total microcystin concentration, and microcystins synthetase gene (mcyA) expression in lab-grown strains of Microcystis NIES 843 (reference strain), KW (Wangsong Reservoir, South Korea), and Durgakund (Varanasi, India) under different nutrient regimes (nitrogen, phosphorus, and boron). Higher level of nitrogen and boron resulted in increased growth (avg...
2016: BioMed Research International
Fiona D'Mello, Nady Braidy, Helder Marçal, Gilles Guillemin, Fanny Rossi, Mirielle Chinian, Dominique Laurent, Charles Teo, Brett A Neilan
Toxins produced by cyanobacteria and dinoflagellates have increasingly become a public health concern due to their degenerative effects on mammalian tissue and cells. In particular, emerging evidence has called attention to the neurodegenerative effects of the cyanobacterial toxin β-N-methylamino-L-alanine (BMAA). Other toxins such as the neurotoxins saxitoxin and ciguatoxin, as well as the hepatotoxic microcystin, have been previously shown to have a range of effects upon the nervous system. However, the capacity of these toxins to cause neurodegeneration in human cells has not, to our knowledge, been previously investigated...
October 29, 2016: Neurotoxicity Research
Min Ma, Fuwei Pi, Jiasheng Wang, Jian Ji, Xiulan Sun
Humans are most likely to be exposed to microcystins (MCs) combined with other water pollutants rather than to individual compounds through the consumption of contaminated drinking water or through recreational activities, such as swimming. However, the combined effects of MC-LR, estradiol (EST), and ractopamine (RAC) have not been extensively researched. The goal of this study was to investigate the combined effects of these compounds. For this purpose, cytotoxicity was evaluated in HepG2 cells treated with single or combined doses of MC-LR, EST, and RAC based on concentration addition (CA), independent action (IA), and Chou-Talalay's combination-index (CI) methods...
October 23, 2016: Chemosphere
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