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Se Hyeon Jang, Hae Jin Jeong, Øjvind Moestrup, Nam Seon Kang, Sung Yeon Lee, Kyung Ha Lee, Kyeong Ah Seong
A small (7-11 μm long), dinoflagellate with thin amphiesmal plates was isolated into culture from a water sample collected in coastal waters off Yeosu, southern Korea, and examined by LM, SEM, and TEM, and molecular analyses. The hemispheric episome was smaller than the hyposome. The nucleus was oval and situated from the central to the episomal region of the cell. A large yellowish-brown chloroplast was located at the end of the hyposome, and some small chloroplasts extended into the periphery of the episome...
October 25, 2016: Journal of Phycology
Yang-Hang Chen, Ya-Hui Gao, Chang-Ping Chen, Jun-Rong Liang, Lin Sun, Yu Zhen, Ling Qiao
Seasonal variations of phytoplankton assemblages were examined in a scallop culture sea area of Bohai Bay (China) with regard to some major physical and chemical variables. Samples were collected at three stations from July 2011 to September 2013. A total of 134 species belong to 4 phyla were identified, of which 104 were diatoms, 27 were dinoflagellates, 1 was euglenophyte and 2 were chrysophytes. The cells abundance in autumn (55.44×10(3)cells/L) was higher than that in summer (6.99×10(3)cells/L), spring (3...
October 19, 2016: Marine Pollution Bulletin
Jahir Orozco, Elisa Villa, Carmem-Lara Manes, Linda K Medlin, Delphine Guillebault
Harmful algal blooms (HABs) are becoming more frequent as climate changes, with tropical species moving northward. Monitoring programs detecting the presence of toxic algae before they bloom are of paramount importance to protect aquatic ecosystems, aquaculture, human health and local economies. Rapid and reliable species identification methods using molecular barcodes coupled to biosensor detection tools have received increasing attention over the past decade as an alternative to the impractical standard microscopic counting-based techniques...
December 1, 2016: Talanta
Xin-Xin Lu, Zhao-Hui Wang, Jie Feng
Dinoflagellate cysts (dinocysts), biogenic elements and metals were analyzed from sediment cores collected from Zhelin Bay of the South China Sea in December 2008 to understand the environmental changes over the past 50years. Dinocyst concentrations ranged from 0cysts/g to 770cysts/g, and they were dominated by heterotrophic taxa. There was a clear increase trend upcore for biogenic elements, except for biogenic silica. Metals originated from both the lithogenic source and human activities, and significantly increased after 1985-1995...
October 16, 2016: Marine Pollution Bulletin
Hela Ben-Gharbia, Ons Kéfi-Daly Yahia, Zouher Amzil, Nicolas Chomérat, Eric Abadie, Estelle Masseret, Manoella Sibat, Habiba Zmerli Triki, Habiba Nouri, Mohamed Laabir
Harmful benthic dinoflagellates, usually developing in tropical areas, are expanding to temperate ecosystems facing water warming. Reports on harmful benthic species are particularly scarce in the Southern Mediterranean Sea. For the first time, three thermophilic benthic dinoflagellates (Ostreopsis cf. ovata, Prorocentrum lima and Coolia monotis) were isolated from Bizerte Bay (Tunisia, Mediterranean) and monoclonal cultures established. The ribotyping confirmed the morphological identification of the three species...
October 15, 2016: Toxins
Beatrix Siemering, Eileen Bresnan, Stuart C Painter, Chris J Daniels, Mark Inall, Keith Davidson
The edge of the North West European Shelf (NWES) is characterised by a steep continental slope and a northward flowing slope current. These topographic/hydrographic features separate oceanic water and shelf water masses hence potentially separate phytoplankton communities. The slope current may facilitate the advective transport of phytoplankton, with mixing at the shelf edge supporting nutrient supply and therefore phytoplankton production. On the west Scottish shelf in particular, little is known about the phytoplankton communities in and around the shelf break and adjacent waters...
2016: PloS One
Vittoria Roncalli, Jefferson T Turner, David Kulis, Donald M Anderson, Petra H Lenz
Inshore and offshore waters of the Gulf of Maine (USA) have spring/summer harmful algal blooms (HABs) of the toxic dinoflagellate Alexandrium fundyense, which is responsible for paralytic shellfish poisoning (PSP) in humans. The calanoid copepod Calanus finmarchicus co-occurs with A. fundyense during the seasonal blooms. At that time, C. finmarchicus population abundances are high, dominated by immature copepods preparing for diapause, and by actively-reproducing adults. High survival has been reported for copepods exposed to toxic A...
January 2016: Harmful Algae
Mindy L Richlen, Oliver Zielinski, Lars Holinde, Urban Tillmann, Allan Cembella, Yihua Lyu, Donald M Anderson
The bloom-forming dinoflagellate Alexandrium fundyense has been extensively studied due its toxin-producing capabilities and consequent impacts to human health and economies. This study investigated the prevalence of resting cysts of A. fundyense in western Greenland and Iceland to assess the historical presence and magnitude of bloom populations in the region, and to characterize environmental conditions during summer, when bloom development may occur. Analysis of sediments collected from these locations showed that Alexandrium cysts were present at low to moderate densities in most areas surveyed, with highest densities observed in western Iceland...
2016: Marine Ecology Progress Series
Liliang Guo, Zhenghong Sui, Yuan Liu
Miseq sequencing and data analysis for the actin gene and v9 region of 18S rDNA of 7 simulated samples consisting of different mixture of dinoflagellates and diatoms were carried out. Not all the species were detectable in all the 18S v9 samples, and sequence percent in all the v9 samples were not consistent with the corresponding cell percent which may suggest that 18S rDNA copy number in different cells of these species differed greatly which result in the large deviation of the amplification. And 18S rDNA amplification of the microalgae was prone to be contaminated by fungus...
October 10, 2016: Scientific Reports
Yim Ling Mak, Jing Li, Chih-Ning Liu, Shuk Han Cheng, Paul K S Lam, Jinping Cheng, Leo L Chan
Ciguatoxins (CTXs) are natural biotoxins produced by benthic dinoflagellates of the genus Gambierdiscus, which are bioaccumulated and biotransformed along food chains in coral ecosystems. They are neurotoxins that activate voltage-gated sodium channels and disrupt ion conductance in the excitable tissues. Pacific ciguatoxin-1 (P-CTX-1) is the most prevalent and potent CTX congener present in fishes from the Pacific Ocean. In this study, P-CTX-1 was administrated to larval marine medaka (2h post-hatch) via microinjection...
October 1, 2016: Journal of Hazardous Materials
Laura Prioretti, Mario Giordano
The Sulfate Facilitation Hypothesis suggests that changes in ocean sulfate concentration influenced the rise to dominance of phytoplankton species of the red lineage. The mechanistic reasons for this phenomenon are not yet understood. We thus started to address this question by investigating the differences in S utilization by algae of the green and red lineages and in cyanobacteria cultured in the presence of either 5 mmol. L(-1) (approximately equivalent to Paleozoic ocean concentrations) or 30 mmol. L(-1) (corresponding to post-Mesozoic/extant concentrations) sulfate...
September 22, 2016: Journal of Phycology
Justin R Perrault, Katherine D Bauman, Taylor M Greenan, Patricia C Blum, Michael S Henry, Catherine J Walsh
Blooms of Karenia brevis (also called red tides) occur almost annually in the Gulf of Mexico. The health effects of the neurotoxins (i.e., brevetoxins) produced by this toxic dinoflagellate on marine turtles are poorly understood. Florida's Gulf Coast represents an important foraging and nesting area for a number of marine turtle species. Most studies investigating brevetoxin exposure in marine turtles thus far focus on dead and/or stranded individuals and rarely examine the effects in apparently "healthy" free-ranging individuals...
October 1, 2016: Aquatic Toxicology
M Sendra, D Sánchez-Quiles, J Blasco, I Moreno-Garrido, L M Lubián, S Pérez-García, A Tovar-Sánchez
Given the large numbers of sunbathers on beaches, sunscreen compounds are being released into the coastal aquatic environment in significant amounts. Until now the effect of these potential pollutants on microbiota has been not well-known. Phytoplankton is a key component of the microbiota community. It forms the basis of the aquatic trophic networks, and any change in the natural population of phytoplankton can affect the structure of aquatic biota. This paper describes an experiment performed outdoors (in natural sunlight conditions including ultraviolet radiation (UVR) and with UVR blocked) on mixed microalgae populations (four species from different key marine taxonomic groups, Nannochloropsis gaditana, Chaetoceros gracilis, Pleurochrysis roscoffensis and Amphidinium carterae), for three days, exposed to a range of concentrations of three commercial sunscreens (with variable TiO2 concentrations: highest concentration for sunscreen C, followed by sunscreen A; and sunscreen B did not contain TiO2 in its composition)...
October 4, 2016: Environment International
Zinaida M Kaskova, Aleksandra S Tsarkova, Ilia V Yampolsky
Bioluminescence (BL) is a spectacular phenomenon involving light emission by live organisms. It is caused by the oxidation of a small organic molecule, luciferin, with molecular oxygen, which is catalysed by the enzyme luciferase. In nature, there are approximately 30 different BL systems, of which only 9 have been studied to various degrees in terms of their reaction mechanisms. A vast range of in vitro and in vivo analytical techniques have been developed based on BL, including tests for different analytes, immunoassays, gene expression assays, drug screening, bioimaging of live organisms, cancer studies, the investigation of infectious diseases and environmental monitoring...
September 12, 2016: Chemical Society Reviews
Sara F Ferreiro, Natalia Vilariño, Cristina Carrera, M Carmen Louzao, Germán Santamarina, Antonio G Cantalapiedra, J Manuel Cifuentes, Andrés Crespo, Luis M Botana
Yessotoxins (YTX) and azaspiracids (AZAs) are marine toxins produced by phytoplanktonic dinoflagellates that get accumulated in filter feeding shellfish and finally reach human consumers through the food web. Both toxin classes are worldwide distributed, and food safety authorities have regulated their content in shellfish in many countries. Recently, YTXs and AZAs have been described as compounds with subacute cardiotoxic potential in rats owed to alterations of the cardiovascular function and ultrastructural heart damage...
October 5, 2016: Archives of Toxicology
Courtney C Cocilova, Sarah L Milton
Harmful algal blooms are increasing in frequency and extent worldwide and occur nearly annually off the west coast of Florida where they affect both humans and wildlife. The dinoflagellate Karenia brevis is a key organism in Florida red tides that produces a suite of potent neurotoxins collectively referred to as the brevetoxins (PbTx). Brevetoxins bind to and open voltage gated sodium channels (VGSC), increasing cell permeability in excitable cells and depolarizing nerve and muscle tissue. Exposed animals may thus show muscular and neurological symptoms including head bobbing, muscle twitching, paralysis, and coma; large HABs can result in significant morbidity and mortality of marine life, including fish, birds, marine mammals, and sea turtles...
September 28, 2016: Aquatic Toxicology
Naohisa Wada, Frederic J Pollock, Bette L Willis, Tracy Ainsworth, Nobuhiro Mano, David G Bourne
In situ visualization of microbial communities within their natural habitats provides a powerful approach to explore complex interactions between microorganisms and their macroscopic hosts. Specifically, the application of fluorescence in situ hybridization (FISH) to simultaneously identify and visualize diverse microbial taxa associated with coral hosts, including symbiotic algae (Symbiodinium), Bacteria, Archaea, Fungi and protists, could help untangle the structure and function of these diverse taxa within the coral holobiont...
2016: PeerJ
S J Taipale, K Vuorio, U Strandberg, K K Kahilainen, M Järvinen, M Hiltunen, E Peltomaa, P Kankaala
Fish are an important source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) for birds, mammals and humans. In aquatic food webs, these highly unsaturated fatty acids (HUFA) are essential for many physiological processes and mainly synthetized by distinct phytoplankton taxa. Consumers at different trophic levels obtain essential fatty acids from their diet because they cannot produce these sufficiently de novo. Here, we evaluated how the increase in phosphorus concentration (eutrophication) or terrestrial organic matter inputs (brownification) change EPA and DHA content in the phytoplankton...
September 26, 2016: Environment International
Thomas Chun-Hung Lee, Fiona Long-Yan Fong, Kin-Chung Ho, Fred Wang-Fat Lee
Diarrhetic shellfish poisoning (DSP) is a gastrointestinal disorder caused by the consumption of seafood contaminated with okadaic acid (OA) and dinophysistoxins (DTXs). OA and DTXs are potent inhibitors of protein phosphatases 2A, 1B, and 2B, which may promote cancer in the human digestive system. Their expression in dinoflagellates is strongly affected by nutritional and environmental factors. Studies have indicated that the level of these biotoxins is inversely associated with the growth of dinoflagellates at low concentrations of nitrogen or phosphorus, or at extreme temperature...
2016: Toxins
Michael L Brosnahan, Lourdes Velo-Suárez, David K Ralston, Sophia E Fox, Taylor R Sehein, Alexi Shalapyonok, Heidi M Sosik, Robert J Olson, Donald M Anderson
Transitions between life cycle stages by the harmful dinoflagellate Alexandrium fundyense are critical for the initiation and termination of its blooms. To quantify these transitions in a single population, an Imaging FlowCytobot (IFCB), was deployed in Salt Pond (Eastham, Massachusetts), a small, tidally flushed kettle pond that hosts near annual, localized A. fundyense blooms. Machine-based image classifiers differentiating A. fundyense life cycle stages were developed and results were compared to manually corrected IFCB samples, manual microscopy-based estimates of A...
November 2015: Limnology and Oceanography
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