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plankton toxins

Denice C Bay, Carol A Stremick, Carmine J Slipski, Raymond J Turner
Escherichia coli possesses many secondary active multidrug resistance transporters (MDTs) that confer overlapping substrate resistance to a broad range of antimicrobials via proton and/or sodium motive force. It is uncertain whether redundant MDTs uniquely alter cell survival when cultures grow planktonically or as biofilms. In this study, the planktonic and biofilm growth and antimicrobial resistance of 13 E. coli K-12 single MDT gene deletion strains in minimal and rich media were determined. Antimicrobial tolerance to tetracycline, tobramycin and benzalkonium were also compared for each ΔMDT strain...
November 22, 2016: Research in Microbiology
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
Magdalena Kwiatek, Sylwia Parasion, Paweł Rutyna, Lidia Mizak, Romuald Gryko, Marcin Niemcewicz, Alina Olender, Małgorzata Łobocka
Pseudomonas aeruginosa is frequently identified as a cause of diverse infections and chronic diseases. It forms biofilms and has natural resistance to several antibiotics. Strains of this pathogen resistant to new-generation beta-lactams have emerged. Due to the difficulties associated with treating chronic P. aeruginosa infections, bacteriophages are amongst the alternative therapeutic options being actively researched. Two obligatorily lytic P. aeruginosa phages, vB_PaeM_MAG1 (MAG1) and vB_PaeP_MAG4 (MAG4), have been isolated and characterized...
November 4, 2016: Research in Microbiology
Yong-Guy Kim, Jin-Hyung Lee, Giyeon Gwon, Soon-Il Kim, Jae Gyu Park, Jintae Lee
Enterohemorrhagic Escherichia coli O157:H7 (EHEC) has caused foodborne outbreaks worldwide and the bacterium forms antimicrobial-tolerant biofilms. We investigated the abilities of various plant essential oils and their components to inhibit biofilm formation by EHEC. Bay, clove, pimento berry oils and their major common constituent eugenol at 0.005% (v/v) were found to markedly inhibit EHEC biofilm formation without affecting planktonic cell growth. In addition, three other eugenol derivatives isoeugenol, 2-methoxy-4-propylphenol, and 4-ethylguaiacol had antibiofilm activity, indicating that the C-1 hydroxyl unit, the C-2 methoxy unit, and C-4 alkyl or alkane chain on the benzene ring of eugenol play important roles in antibiofilm activity...
November 3, 2016: Scientific Reports
Yvonne T Wu, Connie Tam, Lucia S Zhu, David J Evans, Suzanne M J Fleiszig
PURPOSE: The type III secretion system (T3SS) is a significant virulence determinant for Pseudomonas aeruginosa. Using a rodent model, we found that contact lens (CL)-related corneal infections were associated with lens surface biofilms. Here, we studied the impact of human tear fluid on CL-associated biofilm growth and T3SS expression. METHODS: P. aeruginosa biofilms were formed on contact lenses for up to 7 days with or without human tear fluid, then exposed to tear fluid for 5 or 24 h...
September 23, 2016: Ocular Surface
Jessica V Trout-Haney, Zachary T Wood, Kathryn L Cottingham
Cyanobacteria and their toxins have received significant attention in eutrophic temperate and tropical systems where conspicuous blooms of certain planktonic taxa release toxins into fresh water, threatening its potability and safe use for recreation. Although toxigenic cyanobacteria are not confined to high nutrient environments, bloom-forming species, or planktonic taxa, these other situations are studied les often studied. For example, toxin production in picoplankton and benthic cyanobacteria-the predominant photoautotrophs found in polar lakes-is poorly understood...
2016: Toxins
David M Needham, Jed A Fuhrman
Marine phytoplankton perform approximately half of global carbon fixation, with their blooms contributing disproportionately to carbon sequestration(1), and most phytoplankton production is ultimately consumed by heterotrophic prokaryotes(2). Therefore, phytoplankton and heterotrophic community dynamics are important in modelling carbon cycling and the impacts of global change(3). In a typical bloom, diatoms dominate initially, transitioning over several weeks to smaller and motile phytoplankton(4). Here, we show unexpected, rapid community variation from daily rRNA analysis of phytoplankton and prokaryotic community members following a bloom off southern California...
2016: Nature Microbiology
Magdalena Grabowska, Hanna Mazur-Marzec
Study results show continuous summer-autumn dominance of toxic cyanobacteria in plankton not only in the strongly eutrophicated lowland Siemianówka reservoir, but also along 130 km of Narew river below the lake. The negative effects of eutrophication of the reservoir reach far outside its boundaries. One of the symptoms of eutrophication was a mass development of cyanobacteria, including the toxin-producing Planktothrix agardhii. In the reservoir, the biomass of the species strongly correlated with the concentration of microcystins...
December 0: Environmental Monitoring and Assessment
Mehbuba Rehim, Zhenzhen Zhang, Ahmadjan Muhammadhaji
A mathematical model describing the interaction of nutrient-plankton is investigated in this paper. In order to account for the time needed by the phytoplankton to mature after which they can release toxins, a discrete time delay is incorporated into the system. Moreover, it is also taken into account discrete time delays which indicates the partially recycled nutrient decomposed by bacteria after the death of biomass. In the first part of our analysis the sufficient conditions ensuring local and global asymptotic stability of the model are obtained...
2016: SpringerPlus
Yongbo Liu, Fang Liu, Chao Wang, Zhanjun Quan, Junsheng Li
The non-target effects of transgenic plants are issues of concern; however, their impacts in cultivated agricultural fields and adjacent natural aquatic ecosystems are poorly understood. We conducted field experiments during two growing seasons to determine the effects of cultivating Bacillus thuringiensis (Bt)-transgenic rice on the phytoplankton and zooplankton communities in a paddy field and an adjacent ditch. Bt toxin was detected in soil but not in water. Water quality was not significantly different between non-Bt and Bt rice fields, but varied among up-, mid- and downstream locations in the ditch...
September 15, 2016: Science of the Total Environment
Paula Mariela González, Susana Puntarulo
The hypothesis presented here is that oxidative and/or nitrosative metabolism in the bivalve Mytilus edulis platensis is altered by the presence of planktonic toxins. Digestive glands (DG) were isolated from specimens collected in the Argentinean Sea during summer, winter and spring (in the presence of harmful planktonic toxins). The labile iron pool content was not significantly different in DG from animals collected in summer and winter, but was 2.3-fold increased in samples from spring compared to summer collected mollusks...
October 2016: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
Emily R Schwartz, Remington X Poulin, Nazia Mojib, Julia Kubanek
Covering: January 2013 to online publication December 2014This review summarizes recent research in the chemical ecology of marine pelagic ecosystems, and aims to provide a comprehensive overview of advances in the field in the time period covered. In order to highlight the role of chemical cues and toxins in plankton ecology this review has been organized by ecological interaction types starting with intraspecific interactions, then interspecific interactions (including facilitation and mutualism, host-parasite, allelopathy, and predator-prey), and finally community and ecosystem-wide interactions...
July 28, 2016: Natural Product Reports
Chi-Ching Lee, Jinru Chen, Joseph F Frank
Shiga toxin-producing Escherichia coli (STEC) strains produce extracellular cellulose and colanic acid, which may influence stress tolerance. This study investigates the role of these extracellular polymers on the tolerance of STEC to chlorine treatment after attachment to lettuce and spinach. Four STEC strains, two wild-type cellulose-producing and their cellulose-deficient derivatives, were used. One strain pair produced colanic acid in addition to cellulose. Spinach and lettuce with attached cells were treated with chlorinated water (50 and 150 ppm of free chlorine)...
April 2016: Journal of Food Protection
Amanda Svoboda, Angela Shaw, John Dzubak, Aubrey Mendonca, Lester Wilson, Ajay Nair
Over the past few years, foodborne disease outbreaks linked to enteric pathogens present on cantaloupe and watermelon surfaces have raised concerns in the melon industry. This research evaluated the effectiveness of commercially available produce sanitizers against selected foodborne pathogens, both in cell suspensions and on the outer rind surface of melons. The sanitizers (65 and 200 ppm of chlorine, 5 and 35% hydrogen peroxide, 5 and 50 ppm of liquid chlorine dioxide, various hydrogen peroxide-acid combinations, 0...
April 2016: Journal of Food Protection
N Touzet, D McCarthy, A Gill, G T A Fleming
The eutrophication of lakes is typically associated with high biomass proliferations of potentially toxic cyanobacteria. At a regional level, the sustainable management of water resources necessitates an approach that recognises the interconnectivity of multiple water systems within river catchments. This study examined the dynamics in summer diversity of planktonic cyanobacterial communities and microcystin toxin concentrations in two inter-connected lakes from the west of Ireland prone to nutrient enrichment...
May 15, 2016: Science of the Total Environment
Kenneth L Urish, Peter W DeMuth, Brian W Kwan, David W Craft, Dongzhu Ma, Hani Haider, Rocky S Tuan, Thomas K Wood, Charles M Davis
BACKGROUND: The continued presence of biofilm may be one cause of the high risk of failure observed with irrigation and débridement with component retention in acute periprosthetic joint infection (PJI). There is a poor understanding of the role of biofilm antibiotic tolerance in PJI. QUESTIONS/PURPOSES: (1) Do increasing doses of cefazolin result in decreased viable biofilm mass on arthroplasty materials? (2) Is cefazolin resistance phenotypic or genotypic? (3) Is biofilm viability a function of biofilm depth after treatment with cefazolin? (4) Is the toxin-antitoxin system, yoeB expression, associated with antibiotic stress? METHODS: Methicillin-sensitive Staphylococcus aureus biofilm was cultured on total knee arthroplasty (TKA) materials and exposed to increasing doses of cefazolin (control, 0...
July 2016: Clinical Orthopaedics and related Research
Xi Zhang, Jiaru Fang, Yingchang Zou, Ling Zou, Ning Hu, Ping Wang
Marine toxins are produced by plankton and do a great harm to human through food chain by accumulating in shellfishes and fishes. It is highly required and favorable to develop novel methods for the rapid and efficient detection of marine toxins to avoid the poisoning cases that have occurred frequently in many countries. This study presents a real-time Love Wave biosensor for the rapid detection of okadaic acid (OA), which used HepG2 cell lines as the sensing elements. The results indicate that this cell-based biosensor can provide real-time information of cellular activities induced by okadaic acid and has a higher sensitivity than the conventional cell-based assay...
2015: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
M E Diodati, A H Bates, W G Miller, M Q Carter, Y Zhou, M T Brandl
Escherichia coli O111 is an emerging non-O157:H7 serotype of Shiga toxin-producing E. coli (STEC). We previously reported that outbreak and environmental, but not sporadic-case, strains of STEC O111 share a distinct aggregation phenotype (M. E. Diodati, A. H. Bates, M. B. Cooley, S. Walker, R. E. Mandrell, and M. T. Brandl, Foodborne Pathog Dis 12:235-243, 2015, We show here the natural occurrence of nonaggregative variants in single STEC O111 strains. These variants do not produce curli fimbriae and lack RpoS function but synthesize cellulose...
December 28, 2015: Applied and Environmental Microbiology
S N P Suriyanti, Gires Usup
Screening of the occurrence of potentially toxic diatoms was carried out at two sites of cage cultures in Tebrau Straits, Johor. Phytoplankton samples from Sungai Pendas and Teluk Sengat were collected using a 20 μm mesh plankton net and salinity was recorded in-situ. Nitzschia and Pseudo-nitzschia cells were isolated and established into clonal cultures. All cultures were tested for domoic acid using HPLC-UV analysis and verified by LC-MS analysis. Three Nitzschia spp. and one Pseudo-nitzschia sp. were identified from these locations...
December 15, 2015: Toxicon: Official Journal of the International Society on Toxinology
Tyler D Scherr, Mark L Hanke, Ouwen Huang, David B A James, Alexander R Horswill, Kenneth W Bayles, Paul D Fey, Victor J Torres, Tammy Kielian
UNLABELLED: The macrophage response to planktonic Staphylococcus aureus involves the induction of proinflammatory microbicidal activity. However, S. aureus biofilms can interfere with these responses in part by polarizing macrophages toward an anti-inflammatory profibrotic phenotype. Here we demonstrate that conditioned medium from mature S. aureus biofilms inhibited macrophage phagocytosis and induced cytotoxicity, suggesting the involvement of a secreted factor(s). Iterative testing found the active factor(s) to be proteinaceous and partially agr-dependent...
2015: MBio
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