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https://www.readbyqxmd.com/read/29724342/characterization-of-oceanic-noctiluca-blooms-not-associated-with-hypoxia-in-the-northeastern-arabian-sea
#1
Aneesh A Lotliker, S K Baliarsingh, Vera L Trainer, Mark L Wells, Cara Wilson, T V S Udaya Bhaskar, Alakes Samanta, S R Shahimol
Intense blooms of the heterotrophic dinoflagellate, green Noctiluca scintillans, have been reported annually in the Northern Arabian Sea since the early 2000s. Although not known to produce organic toxins, these blooms are still categorized as a harmful due to their association with massive fish mortalities. Recent work has attributed these blooms to the vertical expansion of the oxygen minimum zone, driven by cultural eutrophication from major coastal cities in western India. As diatoms are preferred prey of green Noctiluca scintillans, more frequent blooms of this mixotroph will likely impact the productivity of important fisheries in the region...
April 2018: Harmful Algae
https://www.readbyqxmd.com/read/29614044/toxic-cyanobacteria-in-svalbard-chemical-diversity-of-microcystins-detected-using-a-liquid-chromatography-mass-spectrometry-precursor-ion-screening-method
#2
Julia Kleinteich, Jonathan Puddick, Susanna A Wood, Falk Hildebrand, H Dail Laughinghouse Iv, David A Pearce, Daniel R Dietrich, Annick Wilmotte
Cyanobacteria synthesize a large variety of secondary metabolites including toxins. Microcystins (MCs) with hepato- and neurotoxic potential are well studied in bloom-forming planktonic species of temperate and tropical regions. Cyanobacterial biofilms thriving in the polar regions have recently emerged as a rich source for cyanobacterial secondary metabolites including previously undescribed congeners of microcystin. However, detection and detailed identification of these compounds is difficult due to unusual sample matrices and structural congeners produced...
April 3, 2018: Toxins
https://www.readbyqxmd.com/read/29602500/differential-toxin-response-of-pseudo-nitzschia-multiseries-as-a-function-of-nitrogen-speciation-in-batch-and-continuous-cultures-and-during-a-natural-assemblage-experiment
#3
Regina L Radan, William P Cochlan
The toxigenic diatom Pseudo-nitzschia multiseries Hasle, isolated from the U.S. Pacific Northwest, was examined in unialgal laboratory cultures and in natural assemblages during shipboard experiments, to examine cellular growth and domoic acid (DA) production as a function of nitrogen (N) substrate and availability expected during bloom development and decline. Laboratory experiments utilizing batch cultures conducted at saturating (120 μmol photons m-2  s-1 ) photosynthetic photon flux density (PPFD), demonstrated that P...
March 2018: Harmful Algae
https://www.readbyqxmd.com/read/29572482/bacteriophages-are-more-virulent-to-bacteria-with-human-cells-than-they-are-in-bacterial-culture-insights-from-ht-29-cells
#4
Jinyu Shan, Ananthi Ramachandran, Anisha M Thanki, Fatima B I Vukusic, Jakub Barylski, Martha R J Clokie
Bacteriophage therapeutic development will clearly benefit from understanding the fundamental dynamics of in vivo phage-bacteria interactions. Such information can inform animal and human trials, and much can be ascertained from human cell-line work. We have developed a human cell-based system using Clostridium difficile, a pernicious hospital pathogen with limited treatment options, and the phage phiCDHS1 that effectively kills this bacterium in liquid culture. The human colon tumorigenic cell line HT-29 was used because it simulates the colon environment where C...
March 23, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29426121/the-impact-of-human-activities-and-lifestyles-on-the-interlinked-microbiota-and-health-of-humans-and-of-ecosystems
#5
REVIEW
Lucette Flandroy, Theofilos Poutahidis, Gabriele Berg, Gerard Clarke, Maria-Carlota Dao, Ellen Decaestecker, Eeva Furman, Tari Haahtela, Sébastien Massart, Hubert Plovier, Yolanda Sanz, Graham Rook
Plants, animals and humans, are colonized by microorganisms (microbiota) and transiently exposed to countless others. The microbiota affects the development and function of essentially all organ systems, and contributes to adaptation and evolution, while protecting against pathogenic microorganisms and toxins. Genetics and lifestyle factors, including diet, antibiotics and other drugs, and exposure to the natural environment, affect the composition of the microbiota, which influences host health through modulation of interrelated physiological systems...
June 15, 2018: Science of the Total Environment
https://www.readbyqxmd.com/read/29407801/effects-of-copper-and-butyltin-compounds-on-the-growth-photosynthetic-activity-and-toxin-production-of-two-hab-dinoflagellates-the-planktonic-alexandrium-catenella-and-the-benthic-ostreopsis-cf-ovata
#6
Douglas Couet, Olivier Pringault, Chrystelle Bancon-Montigny, Nicolas Briant, Françoise Elbaz Poulichet, Sophie Delpoux, Ons Kefi-Daly Yahia, BenGharbia Hela, M'Rabet Charaf, Fabienne Hervé, Georges Rovillon, Zouher Amzil, Mohamed Laabir
Controlled laboratory experiments were conducted to test the effects of copper (Cu2+ ) and butyltins (BuT) on the growth, photosynthetic activity and toxin content of two HABs (Harmful Algal Blooms) dinoflagellates, the planktonic Alexandrium catenella and the benthic Ostreopsis cf. ovata. Microalgae were exposed to increasing concentrations of Cu2+ (10-4 to 31 nM) or BuT (0.084 to 84 nM) for seven days. When considering the growth, EC50 values were 0.16 (±0.09) nM and 0.03 (±0.02) nM of Cu2+ for A. catenella and O...
March 2018: Aquatic Toxicology
https://www.readbyqxmd.com/read/29342840/evaluation-of-rapid-early-warning-approaches-to-track-shellfish-toxins-associated-with-dinophysis-and-alexandrium-blooms
#7
Theresa K Hattenrath-Lehmann, Mark W Lusty, Ryan B Wallace, Bennie Haynes, Zhihong Wang, Maggie Broadwater, Jonathan R Deeds, Steve L Morton, William Hastback, Leonora Porter, Karen Chytalo, Christopher J Gobler
Marine biotoxin-contaminated seafood has caused thousands of poisonings worldwide this century. Given these threats, there is an increasing need for improved technologies that can be easily integrated into coastal monitoring programs. This study evaluates approaches for monitoring toxins associated with recurrent toxin-producing Alexandrium and Dinophysis blooms on Long Island, NY, USA, which cause paralytic and diarrhetic shellfish poisoning (PSP and DSP), respectively. Within contrasting locations, the dynamics of pelagic Alexandrium and Dinophysis cell densities, toxins in plankton, and toxins in deployed blue mussels (Mytilus edulis) were compared with passive solid-phase adsorption toxin tracking (SPATT) samplers filled with two types of resin, HP20 and XAD-2...
January 13, 2018: Marine Drugs
https://www.readbyqxmd.com/read/29182651/evidence-of-increased-toxic-alexandrium-tamarense-dinoflagellate-blooms-in-the-eastern-bering-sea-in-the-summers-of-2004-and-2005
#8
Masafumi Natsuike, Rui Saito, Amane Fujiwara, Kohei Matsuno, Atsushi Yamaguchi, Naonobu Shiga, Toru Hirawake, Takashi Kikuchi, Shigeto Nishino, Ichiro Imai
The eastern Bering Sea has a vast continental shelf, which contains various endangered marine mammals and large fishery resources. Recently, high numbers of toxic A. tamarense resting cysts were found in the bottom sediment surface of the eastern Bering Sea shelf, suggesting that the blooms have recently occurred. However, little is known about the presence of A. tamarense vegetative cells in the eastern Bering Sea. This study's goals were to detect the occurrence of A. tamarense vegetative cells on the eastern Bering Sea shelf and to find a relationship between environmental factors and their presence...
2017: PloS One
https://www.readbyqxmd.com/read/29182536/are-we-underestimating-benthic-cyanotoxins-extensive-sampling-results-from-spain
#9
Enrique A Cantoral Uriza, Antonia D Asencio, Marina Aboal
Microcystins (MCs) are potent hepatotoxins, and their presence in water bodies poses a threat to wildlife and human populations. Most of the available information refers to plankton, and much less is known about microcystins in other habitats. To broaden our understanding of the presence and environmental distribution of this group of toxins, we conducted extensive sampling throughout Spain, under a range of conditions and in distinct aquatic and terrestrial habitats. More than half of the tested strains were toxic; concentrations of the hepatotoxin were low compared with planktic communities, and the number of toxic variants identified in each sample of the Spanish strains ranged from 1-3...
November 28, 2017: Toxins
https://www.readbyqxmd.com/read/29149214/new-insights-on-the-species-specific-allelopathic-interactions-between-macrophytes-and-marine-hab-dinoflagellates
#10
Hela Ben Gharbia, Ons Kéfi-Daly Yahia, Philippe Cecchi, Estelle Masseret, Zouher Amzil, Fabienne Herve, Georges Rovillon, Habiba Nouri, Charaf M'Rabet, Douglas Couet, Habiba Zmerli Triki, Mohamed Laabir
Macrophytes are known to release allelochemicals that have the ability to inhibit the proliferation of their competitors. Here, we investigated the effects of the fresh leaves of two magnoliophytes (Zostera noltei and Cymodocea nodosa) and thalli of the macroalgae Ulva rigida on three HAB-forming benthic dinoflagellates (Ostreopsis cf. ovata, Prorocentrum lima, and Coolia monotis). The effects of C. nodosa and U. rigida were also tested against the neurotoxic planktonic dinoflagellate Alexandrium pacificum Litaker sp...
2017: PloS One
https://www.readbyqxmd.com/read/29054868/conditional-function-of-autoaggregative-protein-cah-and-common-cah-mutations-in-shiga-toxin-producing-escherichia-coli
#11
Michelle Qiu Carter, Maria T Brandl, Indira T Kudva, Robab Katani, Matthew R Moreau, Vivek Kapur
Cah is a calcium-binding autotransporter protein involved in autoaggregation and biofilm formation. Although cah is widespread in Shiga toxin-producing Escherichia coli (STEC), we detected mutations in cah at a frequency of 31.3% in this pathogen. In STEC O157:H7 supershedder strain SS17, a large deletion results in a smaller coding sequence, encoding a protein lacking the C-terminal 71 amino acids compared with Cah in STEC O157:H7 strain EDL933. We examined the function of Cah in biofilm formation and host colonization to better understand the selective pressures for cah mutations...
January 1, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29034927/exploring-the-role-of-gs-gogat-cycle-in-microcystin-synthesis-and-regulation-a-model-based-analysis
#12
Swarnendu Banerjee, Abhishek Subramanian, Joydev Chattopadhyay, Ram Rup Sarkar
Toxic cyanobacteria blooms populate water bodies by consuming external nutrients and releasing cyanotoxins that are detrimental for other aquatic species, producing a significant impact on the plankton ecosystem and food web. To exercise population-level control of toxin production, understanding the biochemical mechanisms that explain cyanotoxin regulation within a bacterial cell is of utmost importance. In this study, we explore the mechanistic events to investigate the dependence of toxin microcystin on external nitrogen, a known regulator of the toxin, and for the first time, propose a kinetic model that analyzes the intracellular conditions required to ensure nitrogen dependence on microcystin...
November 21, 2017: Molecular BioSystems
https://www.readbyqxmd.com/read/28895945/excess-labile-carbon-promotes-the-expression-of-virulence-factors-in-coral-reef-bacterioplankton
#13
Anny Cárdenas, Matthew J Neave, Mohamed Fauzi Haroon, Claudia Pogoreutz, Nils Rädecker, Christian Wild, Astrid Gärdes, Christian R Voolstra
Coastal pollution and algal cover are increasing on many coral reefs, resulting in higher dissolved organic carbon (DOC) concentrations. High DOC concentrations strongly affect microbial activity in reef waters and select for copiotrophic, often potentially virulent microbial populations. High DOC concentrations on coral reefs are also hypothesized to be a determinant for switching microbial lifestyles from commensal to pathogenic, thereby contributing to coral reef degradation, but evidence is missing. In this study, we conducted ex situ incubations to assess gene expression of planktonic microbial populations under elevated concentrations of naturally abundant monosaccharides (glucose, galactose, mannose, and xylose) in algal exudates and sewage inflows...
January 2018: ISME Journal
https://www.readbyqxmd.com/read/28893374/cell-differentiation-defines-acute-and-chronic-infection-cell-types-in-staphylococcus-aureus
#14
Juan-Carlos García-Betancur, Angel Goñi-Moreno, Thomas Horger, Melanie Schott, Malvika Sharan, Julian Eikmeier, Barbara Wohlmuth, Alma Zernecke, Knut Ohlsen, Christina Kuttler, Daniel Lopez
A central question to biology is how pathogenic bacteria initiate acute or chronic infections. Here we describe a genetic program for cell-fate decision in the opportunistic human pathogen Staphylococcus aureus, which generates the phenotypic bifurcation of the cells into two genetically identical but different cell types during the course of an infection. Whereas one cell type promotes the formation of biofilms that contribute to chronic infections, the second type is planktonic and produces the toxins that contribute to acute bacteremia...
September 12, 2017: ELife
https://www.readbyqxmd.com/read/28866755/effect-of-microcystins-on-proto-and-metazooplankton-is-more-evident-in-artificial-than-in-natural-waterbodies
#15
J Kosiba, W Krztoń, E Wilk-Woźniak
The increasing proliferation of cyanobacterial blooms prolongs the impact of cyanobacteria on aquatic fauna, potentially altering trophic relationships. We hypothesized that any effect of dissolved microcystins (toxins produced by cyanobacteria) on plankton assemblages would be more evident in artificial reservoirs and ponds than in natural ones. The concentrations of dissolved microcystins in the waters we studied ranged widely from 0.07 to 0.81 μg/L. We showed that the artificial ponds were subjected to more frequent and longer-lasting harmful algal blooms...
February 2018: Microbial Ecology
https://www.readbyqxmd.com/read/28798736/escherichia-coli-o157-h7-acid-sensitivity-correlates-with-flocculation-phenotype-during-nutrient-limitation
#16
Kathryn L Kay, Frederick Breidt, Pina M Fratamico, Gian M Baranzoni, Gwang-Hee Kim, Amy M Grunden, Deog-Hwan Oh
Shiga toxin producing Escherichia coli (STEC) strains vary in acid resistance; however, little is known about the underlying mechanisms that result in strain specific differences. Among 25 STEC O157:H7 strains tested, 7 strains flocculated when grown statically for 18 h in minimal salts medium at 37°C, while 18 strains did not. Interestingly, the flocculation phenotype (cells came out of suspension) was found to correlate with degree of acid sensitivity in an assay with 400 mM acetic acid solution at pH 3...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28793388/morphological-molecular-and-toxin-analysis-of-field-populations-of-alexandrium-genus-from-the-argentine-sea
#17
Elena Fabro, Gastón O Almandoz, Martha Ferrario, Uwe John, Urban Tillmann, Kerstin Toebe, Bernd Krock, Allan Cembella
In the Argentine Sea, blooms of toxigenic dinoflagellates of the Alexandrium tamarense species complex have led to fish and bird mortalities and human deaths as a consequence of paralytic shellfish poisoning (PSP). Yet little is known about the occurrence of other toxigenic species of the genus Alexandrium, or of their toxin composition beyond coastal waters. The distribution of Alexandrium species and related toxins in the Argentine Sea was determined by sampling surface waters on an oceanographic expedition during austral spring from ~39°S to 48°S...
December 2017: Journal of Phycology
https://www.readbyqxmd.com/read/28766269/analysis-of-neurotoxic-amino-acids-from-marine-waters-microbial-mats-and-seafood-destined-for-human-consumption-in-the-arabian-gulf
#18
Aspassia D Chatziefthimiou, Eric J Deitch, William B Glover, James T Powell, Sandra Anne Banack, Renee A Richer, Paul A Cox, James S Metcalf
Human health risks associated with exposure to algal and cyanobacterial toxins (phycotoxins) have been largely concerned with aquatic habitats. People inhabiting desert environments may be exposed to phycotoxins present in terrestrial environments, where cyanobacterial crusts dominate. Seafood comprises a significant portion of the human diet in desert environments proximal to an ocean or sea. Consequently, in addition to terrestrial exposure to cyanotoxins, the potential exists that seafood may be an important exposure route for cyanotoxins in desert regions...
January 2018: Neurotoxicity Research
https://www.readbyqxmd.com/read/28726749/ladder-shaped-ion-channel-ligands-current-state-of-knowledge
#19
REVIEW
Yuri B Shmukler, Denis A Nikishin
Ciguatoxins (CTX) and brevetoxins (BTX) are polycyclic ethereal compounds biosynthesized by the worldwide distributed planktonic and epibenthic dinoflagellates of Gambierdiscus and Karenia genera, correspondingly. Ciguatera, evoked by CTXs, is a type of ichthyosarcotoxism, which involves a variety of gastrointestinal and neurological symptoms, while BTXs cause so-called neurotoxic shellfish poisoning. Both types of toxins are reviewed together because of similar mechanisms of their action. These are the only molecules known to activate voltage-sensitive Na⁺-channels in mammals through a specific interaction with site 5 of its α-subunit and may compete for it, which results in an increase in neuronal excitability, neurotransmitter release and impairment of synaptic vesicle recycling...
July 20, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28675820/grazing-of-nuclearia-thermophila-and-nuclearia-delicatula-nucleariidae-opisthokonta-on-the-toxic-cyanobacterium-planktothrix-rubescens
#20
Sebastian Dirren, Gianna Pitsch, Marisa O D Silva, Thomas Posch
During the last decades, the planktonic cyanobacterium Planktothrix rubescens became a dominant primary producer in many deep pre-alpine lakes. While altered physiochemical conditions due to lake warming seem to favour this cyanobacterial species, its dominance is partly attributed to factors conferring grazing resistance. The rigid structure of the cyanobacterial filaments and toxic secondary metabolites (e.g. microcystins) protect against diverse grazers. Nonetheless, species of the protistan genus Nuclearia (Nucleariidae, Opisthokonta) are able to overcome this grazing protection...
August 2017: European Journal of Protistology
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