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https://www.readbyqxmd.com/read/28095611/hypothesis-gene-rich-plastid-genomes-in-red-algae-may-be-an-outcome-of-nuclear-genome-reduction
#1
Huan Qiu, Jun Mo Lee, Hwan Su Yoon, Debashish Bhattacharya
Red algae (Rhodophyta) putatively diverged from the eukaryote tree of life >1.2 billion years ago and are the source of plastids in the ecologically important diatoms, haptophytes, and dinoflagellates. In general, red algae contain the largest plastid gene inventory among all such organelles derived from primary, secondary, or additional rounds of endosymbiosis. In contrast, their nuclear gene inventory is reduced when compared to their putative sister lineage, the Viridiplantae, and other photosynthetic lineages...
January 17, 2017: Journal of Phycology
https://www.readbyqxmd.com/read/28095537/spotlight-on-the-use-of-nitric-oxide-in-dermatology-what-is-it-what-does-it-do-can-it-become-an-important-addition-to-the-therapeutic-armamentarium-for-skin-disease
#2
James Q Del Rosso, Leon H Kircik
Nitric oxide (NO) is a diatomic gas that is synthesized within and released by multiple host cell types functioning to provide a variety of physiologic and homeostatic effects. Nitric oxide exhibits a variety of effects that relate significantly with outcomes that can provide therapeutic benefit if properly formulated and released. These include anti-inflammatory, immunomodulatory, antimicrobial, vasodilatory properties, and effects that are beneficial to wound healing. Lack of antibiotic resistance appears to be one major advantage of topically delivered NO...
January 1, 2017: Journal of Drugs in Dermatology: JDD
https://www.readbyqxmd.com/read/28092920/evolutionary-genomics-of-the-cold-adapted-diatom-fragilariopsis-cylindrus
#3
Thomas Mock, Robert P Otillar, Jan Strauss, Mark McMullan, Pirita Paajanen, Jeremy Schmutz, Asaf Salamov, Remo Sanges, Andrew Toseland, Ben J Ward, Andrew E Allen, Christopher L Dupont, Stephan Frickenhaus, Florian Maumus, Alaguraj Veluchamy, Taoyang Wu, Kerrie W Barry, Angela Falciatore, Maria I Ferrante, Antonio E Fortunato, Gernot Glöckner, Ansgar Gruber, Rachel Hipkin, Michael G Janech, Peter G Kroth, Florian Leese, Erika A Lindquist, Barbara R Lyon, Joel Martin, Christoph Mayer, Micaela Parker, Hadi Quesneville, James A Raymond, Christiane Uhlig, Ruben E Valas, Klaus U Valentin, Alexandra Z Worden, E Virginia Armbrust, Matthew D Clark, Chris Bowler, Beverley R Green, Vincent Moulton, Cock van Oosterhout, Igor V Grigoriev
The Southern Ocean houses a diverse and productive community of organisms. Unicellular eukaryotic diatoms are the main primary producers in this environment, where photosynthesis is limited by low concentrations of dissolved iron and large seasonal fluctuations in light, temperature and the extent of sea ice. How diatoms have adapted to this extreme environment is largely unknown. Here we present insights into the genome evolution of a cold-adapted diatom from the Southern Ocean, Fragilariopsis cylindrus, based on a comparison with temperate diatoms...
January 16, 2017: Nature
https://www.readbyqxmd.com/read/28088137/forces-on-nuclei-moving-on-autoionizing-molecular-potential-energy-surfaces
#4
Nimrod Moiseyev
Autoionization of molecular systems occurs in diatomic molecules and in small biochemical systems. Quantum chemistry packages enable calculation of complex potential energy surfaces (CPESs). The imaginary part of the CPES is associated with the autoionization decay rate, which is a function of the molecular structure. Molecular dynamics simulations, within the framework of the Born-Oppenheimer approximation, require the definition of a force field. The ability to calculate the forces on the nuclei in bio-systems when autoionization takes place seems to rely on an understanding of radiative damages in RNA and DNA arising from the release of slow moving electrons which have long de Broglie wavelengths...
January 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28080054/bond-dissociation-energies-for-diatomic-molecules-containing-3d-transition-metals-benchmark-scalar-relativistic-coupled-cluster-calculations-for-twenty-molecules
#5
Lan Cheng, Jürgen Gauss, Branko Ruscic, Peter B Armentrout, John F Stanton
Benchmark scalar-relativistic coupled-cluster calculations for dissociation energies of the twenty diatomic molecules containing 3d transition metals in the 3dMLBE20 database (Xu et al., J. Chem. Theory Comput. 2015, 11, 2036) ) are reported. Electron correlation and basis set effects are systematically studied. The agreement between theory and experiment is in general satisfactory. For a subset of sixteen molecules, the standard deviation between computational and experimental values is 9 kJ/mol with the maximum deviation being 15 kJ/mol...
January 12, 2017: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/28080051/prediction-of-bond-dissociation-energies-heat-of-formation-for-diatomic-transition-metal-compounds-ccsd-t-works
#6
Zongtang Fang, Monica Vasiliu, Kirk A Peterson, David A Dixon
It was recently reported (J. Chem. Theory Comput. 2015, 11, 2036-2052) that the coupled cluster singles and doubles with perturbative triples method, CCSD(T), should not be used as a benchmark tool for the prediction of dissociation energies (heats of formation) for the 1st row transition metal diatomics based on a comparison with the experimental thermodynamic values for a set of 20 diatomics. In the present work the bond dissociation energies as well as the heats of formation for those diatomics have been calculated by the Feller-Peterson-Dixon approach at the CCSD(T)/complete basis set (CBS) level of theory including scalar relativistic corrections and correlation of the outer shell of core electrons in addition to the valence electrons...
January 12, 2017: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/28078675/overexpression-of-a-diacylglycerol-acyltransferase-gene-in-phaeodactylum-tricornutum-directs-carbon-towards-lipid-biosynthesis
#7
Jorge Dinamarca, Orly Levitan, G K Kumaraswamy, Desmond S Lun, Paul Falkowski
Under nutrient deplete conditions, diatoms accumulate between 15 to 25% of their dry weight as lipids, primarily as triacylglycerols (TAGs). As in most eukaryotes, these organisms produce TAGs via the acyl-CoA dependent Kennedy pathway. The last step in this pathway is catalyzed by diacylglycerol acyltransferase (DGAT) that acylates diacylglycerol (DAG) to produce TAG. To test our hypothesis that DGAT plays a major role in controlling the flux of carbon towards lipids, we overexpressed a specific type II DGAT gene, DGAT2D, in the model diatom Phaeodactylum tricornutum...
January 12, 2017: Journal of Phycology
https://www.readbyqxmd.com/read/28077324/grk2-as-negative-modulator-of-no-bioavailability-implications-for-cardiovascular-disease
#8
REVIEW
Alessandro Cannavo, Walter J Koch
Nitric oxide (NO), initially identified as endothelium-derived relaxing factor (EDRF), is a gaso-transmitter with important regulatory roles in the cardiovascular, nervous and immune systems. In the former, this diatomic molecule and free radical gas controls vascular tone and cardiac mechanics, among others. In the cardiovascular system, it is now understood that β-adrenergic receptor (βAR) activation is a key modulator of NO generation. Therefore, it is not surprising that the up-regulation of G protein-coupled receptor kinases (GRKs), in particular GRK2, that restrains βAR activity contributes to impaired cardiovascular functions via alteration of NO bioavailability...
January 7, 2017: Cellular Signalling
https://www.readbyqxmd.com/read/28076393/alder-nitrogen-and-lake-ecology-terrestrial-aquatic-linkages-in-the-postglacial-history-of-lone-spruce-pond-southwestern-alaska
#9
Bianca B Perren, Yarrow Axford, Darrell S Kaufman
Diatoms, combined with a multiproxy study of lake sediments (organic matter, N, δ15N, δ13C, biogenic silica, grain size, Cladocera and chironomids, Alnus pollen) from Lone Spruce Pond, Alaska detail the late-glacial to Holocene history of the lake and its response to regional climate and landscape change over the last 14.5 cal ka BP. We show that the immigration of alder (Alnus viridis) in the early Holocene marks the rise of available reactive nitrogen (Nr) in the lake as well as the establishment of a primarily planktonic diatom community...
2017: PloS One
https://www.readbyqxmd.com/read/28074370/comparative-toxicity-of-nano-zno-and-bulk-zno-towards-marine-algae-tetraselmis-suecica-and-phaeodactylum-tricornutum
#10
Jiji Li, Simona Schiavo, Gabriella Rametta, Maria Lucia Miglietta, Vera La Ferrara, Changwen Wu, Sonia Manzo
The wide use of ZnO nanoparticles in a number of products implies an increasing release into the marine environment, resulting in the need to evaluate the potential effects upon organisms, and particularly phytoplankton, being at the base of the throphic chain. To this aim, dose-response curves for the green alga Tetraselmis suecica and the diatom Phaeodactylum tricornutum derived from the exposure to nano ZnO (100 nm) were evaluated and compared with those obtained for bulk ZnO (200 nm) and ionic zinc. The toxic effects to both algae species were reported as no observable effect concentration (NOEC) of growth inhibition and as 1, 10, and 50% effect concentrations (EC1, EC10, and EC50)...
January 10, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28073566/mixotrophy-in-the-phototrophic-dinoflagellate-takayama-helix-family-kareniaceae-predator-of-diverse-toxic-and-harmful-dinoflagellates
#11
Hae Jin Jeong, Jin Hee Ok, An Suk Lim, Ji Eun Kwon, So Jin Kim, Sung Yeon Lee
Takayama spp. are phototrophic dinoflagellates belonging to the family Kareniaceae and have caused fish kills in several countries. Understanding their trophic mode and interactions with co-occurring phytoplankton species are critical steps in comprehending their ecological roles in marine ecosystems, bloom dynamics, and dinoflagellate evolution. To investigate the trophic mode and interactions of Takayama spp., the ability of Takayama helix to feed on diverse algal species was examined, and the mechanisms of prey ingestion were determined...
December 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073557/diatom-nitzschia-navis-varingica-bacillariophyceae-and-its-domoic-acid-production-from-the-mangrove-environments-of-malaysia
#12
Suh Nih Tan, Sing Tung Teng, Hong Chang Lim, Yuichi Kotaki, Stephen S Bates, Chui Pin Leaw, Po Teen Lim
The distribution of the toxic pennate diatom Nitzschia was investigated at four mangrove areas along the coastal brackish waters of Peninsular Malaysia. Eighty-two strains of N. navis-varingica were isolated and established, and their identity confirmed morphologically and molecularly. Frustule morphological characteristics of the strains examined are identical to previously identified N. navis-varingica, but with a sightly higher density of the number of areolae per 1μm (4-7 areolae). Both LSU and ITS rDNAs phylogenetic trees clustered all strains in the N...
December 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073545/a-validated-uplc-ms-ms-method-for-the-surveillance-of-ten-aquatic-biotoxins-in-european-brackish-and-freshwater-systems
#13
Brett Greer, Sara E McNamee, Bas Boots, Lucia Cimarelli, Delphine Guillebault, Karim Helmi, Stefania Marcheggiani, Stefan Panaiotov, Ulrich Breitenbach, Reyhan Akçaalan, Linda K Medlin, Katrin Kittler, Christopher T Elliott, Katrina Campbell
Over the past few decades, there has been an increased frequency and duration of cyanobacterial Harmful Algal Blooms (HABs) in freshwater systems globally. These can produce secondary metabolites called cyanotoxins, many of which are hepatotoxins, raising concerns about repeated exposure through ingestion of contaminated drinking water or food or through recreational activities such as bathing/swimming. An ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) multi-toxin method has been developed and validated for freshwater cyanotoxins; microcystins-LR, -YR, -RR, -LA, -LY and -LF, nodularin, cylindrospermopsin, anatoxin-a and the marine diatom toxin domoic acid...
May 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073538/margalef-revisited-a-new-phytoplankton-mandala-incorporating-twelve-dimensions-including-nutritional-physiology
#14
Patricia M Glibert
Building on the classic depiction of the progression from a diatom to a dinoflagellate bloom as a function of nutrients and turbulence, known as the "Margalef mandala", a new conceptual model or mandala is presented here. The new mandala maps twelve response or effects traits, or environmental characteristics, related to different phytoplankton functional types: (1) relative preference for chemically reduced vs chemically oxidized forms of nitrogen; (2) relative availability of inorganic nitrogen and phosphorus; (3) adaptation to high vs low light and the tendency to be autotrophic vs mixotrophic; (4) cell motility; (5) environmental turbulence; (6) pigmentation quality; (7) temperature; (8) cell size; (9) relative growth rate; (10) relative production of bioactive compounds such as toxins or reactive oxygen species (ROS); (11) r vs K strategy; and (12) fate of the production in terms of grazing...
May 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073535/new-oxylipins-produced-at-the-end-of-a-diatom-bloom-and-their-effects-on-copepod-reproductive-success-and-gene-expression-levels
#15
Chiara Lauritano, Giovanna Romano, Vittoria Roncalli, Angela Amoresano, Carolina Fontanarosa, Mauro Bastianini, Federica Braga, Ylenia Carotenuto, Adrianna Ianora
Diatoms are dominant photosynthetic organisms in the world's oceans and are considered essential in the transfer of energy to higher trophic levels. However, these unicellular organisms produce secondary metabolites deriving from the oxidation of fatty acids, collectively termed oxylipins, with negative effects on predators, such as copepods, that feed on them (e.g. reduction in survival, egg production and hatching success) and, indirectly, on higher trophic levels. Here, a multidisciplinary study (oxylipin measurements, copepod fitness, gene expression analyses, chlorophyll distribution, phytoplankton composition, physico-chemical characteristics) was carried out at the end of the spring diatom bloom in April 2011 in the Northern Adriatic Sea (Mediterranean Sea) in order to deeply investigate copepod-diatom interactions, chemical communication and response pathways...
May 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073532/toxigenic-algae-and-associated-phycotoxins-in-two-coastal-embayments-in-the-ebro-delta-nw-mediterranean
#16
Julia A Busch, Karl B Andree, Jorge Diogène, Margarita Fernández-Tejedor, Kerstin Toebe, Uwe John, Bernd Krock, Urban Tillmann, Allan D Cembella
Harmful Algal Bloom (HAB) surveillance is complicated by high diversity of species and associated phycotoxins. Such species-level information on taxonomic affiliations and on cell abundance and toxin content is, however, crucial for effective monitoring, especially of aquaculture and fisheries areas. The aim addressed in this study was to determine putative HAB taxa and related phycotoxins in plankton from aquaculture sites in the Ebro Delta, NW Mediterranean. The comparative geographical distribution of potentially harmful plankton taxa was established by weekly field sampling throughout the water column during late spring-early summer over two years at key stations in Alfacs and Fangar embayments within the Ebro Delta...
May 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073531/effects-of-the-bloom-of-harmful-benthic-dinoflagellate-ostreopsis-cf-ovata-on-the-microphytobenthos-community-in-the-northern-adriatic-sea
#17
Stefano Accoroni, Tiziana Romagnoli, Salvatore Pichierri, Cecilia Totti
Composition and temporal variation of the microphytobenthos communities of the Conero Riviera (northern Adriatic Sea) were investigated in the course of an annual cycle, focusing on their relationships with blooms of the benthic dinoflagellate Ostreopsis cf. ovata. Sampling was carried out from March 2009 to March 2010 on undisturbed benthic substrata (macroalgae and pebbles). Samples for the study of microphytobenthos were collected with a monthly frequency, while those for the study of Ostreopsis bloom weekly...
May 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073473/how-rising-co2-and-global-warming-may-stimulate-harmful-cyanobacterial-blooms
#18
REVIEW
Petra M Visser, Jolanda M H Verspagen, Giovanni Sandrini, Lucas J Stal, Hans C P Matthijs, Timothy W Davis, Hans W Paerl, Jef Huisman
Climate change is likely to stimulate the development of harmful cyanobacterial blooms in eutrophic waters, with negative consequences for water quality of many lakes, reservoirs and brackish ecosystems across the globe. In addition to effects of temperature and eutrophication, recent research has shed new light on the possible implications of rising atmospheric CO2 concentrations. Depletion of dissolved CO2 by dense cyanobacterial blooms creates a concentration gradient across the air-water interface. A steeper gradient at elevated atmospheric CO2 concentrations will lead to a greater influx of CO2, which can be intercepted by surface-dwelling blooms, thus intensifying cyanobacterial blooms in eutrophic waters...
April 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073463/the-effect-of-exogenous-%C3%AE-n-methylamino-l-alanine-bmaa-on-the-diatoms-phaeodactylum-tricornutum-and-thalassiosira-weissflogii
#19
Sandra Lage, Linnea Ström, Anna Godhe, Sara Rydberg
β-N-methylamino-l-alanine (BMAA), a non-protein amino acid with neurodegenerative features, is known to be produced by cyanobacteria, diatoms and a dinoflagellate. BMAA research has intensified over the last decade, and knowledge has been gained about its bioaccumulation in aquatic and terrestrial ecosystems, toxic effects in model organisms and neurotoxicity in vivo and in vitro. Nevertheless, knowledge of the actual physiological role of BMAA in the producing species or of the ecological factors that regulate BMAA production is still lacking...
September 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073457/production-of-bmaa-and-dab-by-diatoms-phaeodactylum-tricornutum-chaetoceros-sp-chaetoceros-calcitrans-and-thalassiosira-pseudonana-and-bacteria-isolated-from-a-diatom-culture
#20
Damien Réveillon, Véronique Séchet, Philipp Hess, Zouher Amzil
Microalgae have previously been reported to contain β-N-methylamino-l-alanine (BMAA), and the global presence of these primary producers has been associated with the widespread occurrence of BMAA in marine organisms. It has been repeatedly shown that filter-feeding bivalves accumulate phytoplankton species and their toxins. In this study, the concentrations of total soluble BMAA and DAB as a function of growth phase were observed for four non-axenic diatom species (i.e. Phaeodactylum tricornutum, Chaetoceros sp...
September 2016: Harmful Algae
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