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https://www.readbyqxmd.com/read/28823015/effects-of-eutrophication-on-diatom-abundance-biovolume-and-diversity-in-tropical-coastal-waters
#1
Joon Hai Lim, Choon Weng Lee
Diatom abundance, biovolume and diversity were measured over a 2-year period along the Straits of Malacca at two stations with upper (Klang) and lower (Port Dickson) states of eutrophication. Diatom abundance, which ranged from 0.2 × 10(4) to 21.7 × 10(4) cells L(-1) at Klang and 0.9 × 10(3)- 41.3 × 10(3) cells L(-1) at Port Dickson, was influenced partly by nutrient concentrations. At Klang, the diatoms were generally smaller and less diverse (H' = 0.77 ± 0.48) and predominated by Skeletonema spp...
August 3, 2017: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/28822815/enrichment-of-highly-settleable-microalgal-consortia-in-mixed-cultures-for-effluent-polishing-and-low-cost-biomass-production
#2
Yuansheng Hu, Xiaodi Hao, Mark van Loosdrecht, Huiqin Chen
Microalgae cultivation is a promising technology for integrated effluent polishing and biofuel production, but poor separability of microalgal cells hinders its industrial application. This study intended to selectively enrich settleable microalgal consortia in mixed culture by applying "wash-out" pressure, which was realized by controlling settling time (ST) and volume exchange ratio (VER) in photo-SBRs. The results demonstrated that highly settleable microalgal consortia (settling efficiency>97%; SVI = 17-50 mL/g) could be enriched from indigenous algal cultures developed in WWTP's effluent...
August 15, 2017: Water Research
https://www.readbyqxmd.com/read/28822276/exploiting-algal-mineralization-for-nanotechnology-bringing-coccoliths-to-the-fore
#3
REVIEW
Alastair W Skeffington, André Scheffel
Complex mineral structures are produced by many microalgal species. Pioneering work on diatom silica has demonstrated the potential of such structures in nanotechnology. The calcified scales of coccolithophores (coccoliths) have received less attention, but the large diversity of architectures make coccoliths attractive as parts for nano-devices. Currently coccolith calcite can be modified by the incorporation of metal ions or adsorption of enzymes to the surface, but genetic modification of coccolithophores may permit the production of coccoliths with customized architectures and surface properties...
August 16, 2017: Current Opinion in Biotechnology
https://www.readbyqxmd.com/read/28821972/non-deformed-singular-and-non-singular-exponential-type-potentials
#4
J J Pe Na, G Ovando, J Morales, J García-Ravelo
The canonical transformation method applied to the Schrödinger equation to transform it into a second-order differential equation of hypergeometric-type is presented. Starting from there, those exactly solvable multiparameter exponential-type (ME-T) potentials with hypergeometric wavefunctions that belong to the families of radial (singular) and one-dimensional (non-singular) potentials, are obtained. Furthermore, we show how the choice of the involved parameters leads, as particular cases, to different deformed or non-deformed potential models already used in the study of electronic properties of diatomic molecules...
August 18, 2017: Journal of Molecular Modeling
https://www.readbyqxmd.com/read/28818078/development-of-a-silicon-limitation-inducible-expression-system-for-recombinant-protein-production-in-the-centric-diatoms-thalassiosira-pseudonana-and-cyclotella-cryptica
#5
Roshan P Shrestha, Mark Hildebrand
BACKGROUND: An inducible promoter for recombinant protein expression provides substantial benefits because under induction conditions cellular energy and metabolic capability can be directed into protein synthesis. The most widely used inducible promoter for diatoms is for nitrate reductase, however, nitrogen metabolism is tied into diverse aspects of cellular function, and the induction response is not necessarily robust. Silicon limitation offers a means to eliminate energy and metabolic flux into cell division processes, with little other detrimental effect on cellular function, and a protein expression system that works under those conditions could be advantageous...
August 17, 2017: Microbial Cell Factories
https://www.readbyqxmd.com/read/28815594/differential-effects-of-changes-in-spectral-irradiance-on-photoacclimation-primary-productivity-and-growth-in-rhodomonas-salina-cryptophyceae-and-skeletonema-costatum-bacillariophyceae-in-simulated-blackwater-environments
#6
Evelyn Lawrenz, Tammi L Richardson
The underwater light field in blackwater environments is strongly skewed towards the red end of the electromagnetic spectrum due to blue light absorption by colored dissolved organic matter (CDOM). Exposure of phytoplankton to full spectrum irradiance occurs only when cells are mixed up to the surface. We studied the potential effects of mixing-induced changes in spectral irradiance on photoacclimation, primary productivity and growth in cultures of the cryptophyte Rhodomonas salina and the diatom Skeletonema costatum...
August 16, 2017: Journal of Phycology
https://www.readbyqxmd.com/read/28813426/sexual-reproduction-in-plagiogrammacean-diatoms-first-insights-into-the-early-pennates
#7
Irena Kaczmarska, Benjamin S Gray, James M Ehrman, Mary Thaler
The genera Plagiogramma and Dimeregramma are members of a small, but evolutionarily important group of diatoms, the "basal" araphids. They are sister to all other pennates, both araphid and raphid taxa. Thus, their phylogenetic position carries the potential for providing insights into the earliest pennates. We documented sexual reproduction, mating system and sex cell development in the first members of the "basal" araphid clade ever investigated. The mating system in all these species involved heterothally...
2017: PloS One
https://www.readbyqxmd.com/read/28811874/functional-roles-of-an-engineer-species-for-coastal-benthic-invertebrates-and-demersal-fish
#8
Aurélie Chaalali, Anik Brind'Amour, Stanislas F Dubois, Hervé Le Bris
Through their tissues or activities, engineer species create, modify, or maintain habitats and alter the distribution and abundance of many plants and animals. This study investigates key ecological functions performed by an engineer species that colonizes coastal ecosystems. The gregarious tubiculous amphipod Haploops nirae is used as a biological model. According to previous studies, the habitat engineered by H. nirae (i.e., Haploops habitat) could provide food and natural shelter for several benthic species such as benthic diatoms belonging to the gender Navicula, the micrograzer Geitodoris planata, or the bivalve Polititapes virgineus...
August 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/28811644/the-link-between-enso-like-forcing-and-hydroclimate-variability-of-coastal-east-asia-during-the-last-millennium
#9
Jungjae Park, Jiwoo Han, Qiuhong Jin, Junbeom Bahk, Sangheon Yi
Inconsistent reconstructions of East Asian hydroclimate for the last millennium significantly limit our understanding of the mechanisms behind climate variability during the medieval climate anomaly (MCA) and little ice age (LIA) in the region. In this study, we present new high-resolution multiproxy records (diatom, δ(13)C, C/N, TS) from the Mulyoungari swamp, Jeju Island, South Korea. Our results indicate that El Niño southern oscillation-like variations caused the dry MCA/wet LIA pattern in the study area...
August 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28810785/explicitly-correlated-n-electron-valence-state-perturbation-theory-nevpt2-f12
#10
Yang Guo, Kantharuban Sivalingam, Edward F Valeev, Frank Neese
In this work, explicitly correlated second order N-electron valence state perturbation theory (NEVPT2-F12) has been derived and implemented for the first time. The NEVPT2-F12 algorithm presented here is based on a fully internally contracted wave function and includes the correction of semi-internal excitation subspaces. The algorithm exploits the resolution of identity (RI) approximation to improve the computational efficiency. The overall O(N(5)) scaling of the computational effort is documented. In Sec. III, the dissociation processes of diatomic molecules and the singlet-triplet gap of several systems are studied...
August 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28810223/effects-of-an-allelochemical-in-phaeodactylum-tricornutum-filtrate-on-heterosigma-akashiwo-morphological-physiological-and-growth-effects
#11
Rui Wang, Qiaona Xue, Jiangtao Wang, Liju Tan, Qingchun Zhang, Yue Zhao, Donald M Anderson
The effects of an allelochemical extracted from the culture filtrate of diatom Phaeodactylum tricornutum on the raphidophyte Heterosigma akashiwo were investigated using a series of morphological, physiological and biochemical characters. Growth experiments showed that H. akashiwo was significantly inhibited immediately after exposure to the allelochemical, with many cells rapidly dying and lysing based on microscopic observation. The effects of the allelochemical on the surviving cells were explored using Scanning Electron Microscopy (SEM) and Flow cytometry (FCM), the latter by examination of a suite of physiological parameters (membrane integrity, esterase activity, chlorophyll-a content, membrane potential)...
August 7, 2017: Chemosphere
https://www.readbyqxmd.com/read/28808685/structure-of-a-1-5-mda-adhesin-that-binds-its-antarctic-bacterium-to-diatoms-and-ice
#12
Shuaiqi Guo, Corey A Stevens, Tyler D R Vance, Luuk L C Olijve, Laurie A Graham, Robert L Campbell, Saeed R Yazdi, Carlos Escobedo, Maya Bar-Dolev, Victor Yashunsky, Ido Braslavsky, David N Langelaan, Steven P Smith, John S Allingham, Ilja K Voets, Peter L Davies
Bacterial adhesins are modular cell-surface proteins that mediate adherence to other cells, surfaces, and ligands. The Antarctic bacterium Marinomonas primoryensis uses a 1.5-MDa adhesin comprising over 130 domains to position it on ice at the top of the water column for better access to oxygen and nutrients. We have reconstructed this 0.6-μm-long adhesin using a "dissect and build" structural biology approach and have established complementary roles for its five distinct regions. Domains in region I (RI) tether the adhesin to the type I secretion machinery in the periplasm of the bacterium and pass it through the outer membrane...
August 2017: Science Advances
https://www.readbyqxmd.com/read/28807420/how-the-dispersant-corexit-impacts-the-formation-of-sinking-marine-oil-snow
#13
Uta Passow, Julia Sweet, Antonietta Quigg
The vertical transport of sinking marine oil snow (MOS) and oil-sediment aggregations (OSA) during the Deepwater Horizon (DwH) spill contributed appreciably to the unexpected, and exceptional accumulation of oil on the seafloor. However, the role of the dispersant Corexit in mediating oil-sedimentation is still controversial. Here we demonstrate that the formation of diatom MOS is enhanced by chemically undispersed oil, but inhibited by Corexit-dispersed oil. Nevertheless, the sedimentation rate of oil may at times be enhanced by Corexit application, because of an elevated oil content per aggregate when Corexit is used...
August 11, 2017: Marine Pollution Bulletin
https://www.readbyqxmd.com/read/28803343/sediment-lipid-biomarkers-record-phytoplankton-dynamics-of-lake-heihai-yunnan-province-sw-china-driven-by-climate-warming-since-the-1980s
#14
Yongdong Zhang, Yaling Su, Zhengwen Liu, Jinlei Yu, Miao Jin
Increased phosphorus (P) export from sediments to the overlying water column is a significant factor driving the variation of phytoplankton in productivity and community structure in lakes. However, the lack of long-term instrumental data often impeded analyses attempting to associate dynamics of phytoplankton with variation of internal P loading. Here, elements and lipid biomarkers were analyzed in a sediment core from Lake Heihai, a small, deep, and ultraoligotrophic alpine lake in Haba Mountain, Yunnan Province, SW China...
August 12, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28802096/comparison-of-cleaning-methods-for-delicate-insect-specimens-for-scanning-electron-microscopy
#15
Katharina Schneeberg, René Bauernfeind, Hans Pohl
The objective of the present study was to compare cleaning methods for delicate insect specimens for investigations with scanning electron microscopy (SEM). As typical specimens we used aquatic larvae of mosquitoes, springtails, larvae of mayflies and caterpillars because they are very fragile and large parts of their body consist of soft tissue. Additionally their cuticle is very often covered with dirt, soil particles or other materials. Cleaning with ultrasonic sound, as the most common cleaning method used for SEM, will destroy fragile insects...
August 12, 2017: Microscopy Research and Technique
https://www.readbyqxmd.com/read/28799403/combined-4-component-and-relativistic-pseudopotential-study-of-tho-for-the-electron-electric-dipole-moment-search
#16
L V Skripnikov
A precise theoretical study of the electronic structure of heavy atom diatomic molecules is of key importance to interpret the experiments in the search for violation of time-reversal (T) and spatial-parity (P) symmetries of fundamental interactions in terms of the electron electric dipole moment, eEDM, and dimensionless constant, kT,P, characterizing the strength of the T,P-odd pseudoscalar-scalar electron-nucleus neutral current interaction. The ACME collaboration has recently improved limits on these quantities using a beam of ThO molecules in the electronic H(3)Δ1 state [J...
December 7, 2016: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28799363/bond-dissociation-energies-of-diatomic-transition-metal-selenides-tise-zrse-hfse-vse-nbse-and-tase
#17
Jason J Sorensen, Thomas D Persinger, Andrew Sevy, Jordan A Franchina, Eric L Johnson, Michael D Morse
Predissociation thresholds have been observed in the resonant two-photon ionization spectra of TiSe, ZrSe, HfSe, VSe, NbSe, and TaSe. It is argued that the sharp onset of predissociation corresponds to the bond dissociation energy in each of these molecules due to their high density of states as the ground separated atom limit is approached. The bond dissociation energies obtained are D0(TiSe) = 3.998(6) eV, D0(ZrSe) = 4.902(3) eV, D0(HfSe) = 5.154(4) eV, D0(VSe) = 3.884(3) eV, D0(NbSe) = 4.834(3) eV, and D0(TaSe) = 4...
December 7, 2016: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28797596/an-update-on-aureochromes-phylogeny-mechanism-function
#18
REVIEW
Peter G Kroth, Christian Wilhelm, Tilman Kottke
Light is important for algae, as it warrants metabolic independence via photosynthesis. In addition to the absorption of light by the photosystems, algae possess a variety of specific photoreceptors that allow the quantification of the light fluxes as well as the assessment of light qualities. About a decade ago, aureochromes have been described in the xanthophyte alga Vaucheria frigida. These proteins represent a new type of blue light photoreceptor as they possess both a light-oxygen-voltage (LOV) domain for light reception as well as a basic region leucine zipper (bZIP) domain for DNA binding, indicating that they represent light-driven transcription factors...
July 11, 2017: Journal of Plant Physiology
https://www.readbyqxmd.com/read/28794683/differentiating-iconella-from-surirella-bacillariophyceae-typifying-four-ehrenberg-names-and-a-preliminary-checklist-of-the-african-taxa
#19
Regine Jahn, Wolf-Henning Kusber, Christine Cocquyt
To comply with the new phylogeny within the Surirellales as supported by molecular and morphological data, re-evaluations and re-combinations of taxa from and within the genera Surirella, Cymatopleura, and Stenopterobia and with the re-established genus Iconella are necessary. Since the African diatom flora is rich with taxa from these genera, especially Iconella, and the authors have studied these taxa recently, describing also new taxa, a preliminary checklist of African Iconella and Surirella is here presented...
2017: PhytoKeys
https://www.readbyqxmd.com/read/28794479/the-organizing-effects-of-elevated-co2-on-competition-among-estuarine-primary-producers
#20
Craig S Young, Christopher J Gobler
Fossil fuel combustion, eutrophication, and upwelling introduce excess CO2 into coastal zones. The extent to which marine autotrophs may benefit from elevated CO2 will be a function of their carbon limitation and, among other factors, competition with other primary producers. Here, we report on experiments performed with North Atlantic species of Ulva and Gracilaria grown in situ or exposed to ambient (~400 µatm) and elevated pCO2 (~2500 µatm) and/or subjected to competition with each other and/or with natural plankton assemblages...
August 9, 2017: Scientific Reports
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