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https://www.readbyqxmd.com/read/28628993/the-impact-of-silver-nanoparticles-on-marine-plankton-dynamics-dependence-on-coating-size-and-concentration
#1
Anastasia Tsiola, Paraskevi Pitta, Agnès Junyer Callol, Margarita Kagiorgi, Ioanna Kalantzi, Kyriaki Mylona, Ioulia Santi, Claudio Toncelli, Spyros Pergantis, Manolis Tsapakis
During this study, three microcosm experiments were carried out with natural coastal seawater, collected in the Eastern Mediterranean Sea, in order to assess the effect of silver nanoparticle (AgNP) exposure to natural plankton communities. The impact of coating (branched-polyethyleneimine: BPEI vs. poly-vinylpyrrolidone: PVP), size (40 vs. 60nm), concentration (200, 500, 2000, 5000 and 10,000ng Ag L(-1)) and silver form (dissolved Ag(+) vs. AgNPs) were tested. The results of chlorophyll a concentration revealed that PVP AgNPs caused a higher toxicity than BPEI AgNPs, and this was possibly related to the measured higher dissolution rate...
June 14, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28623567/molecular-identification-and-comparative-evaluation-of-tropical-marine-microalgae-for-biodiesel-production
#2
Sanyo Sabu, I S Bright Singh, Valsamma Joseph
Marine microalgae have emerged as important feedstock for liquid biofuel production. The identification of lipid-rich native microalgal species with high growth rate and optimal fatty acid profile and biodiesel properties is the most challenging step in microalgae-based biodiesel production. In this study, attempts have been made to bio-prospect the biodiesel production potential of marine and brackish water microalgal isolates from the west coast of India. A total of 14 microalgal species were isolated, identified using specific molecular markers and based on the lipid content; seven species with total lipid content above 20% of dry cell weight were selected for assessing biodiesel production potential in terms of lipid and biomass productivities, nile red fluorescence, fatty acid profile and biodiesel properties...
June 16, 2017: Marine Biotechnology
https://www.readbyqxmd.com/read/28488428/contribution-of-charges-in-polyvinyl-alcohol-networks-to-marine-antifouling
#3
Wufang Yang, Peng Lin, Daocang Cheng, Longzhou Zhang, Yang Wu, Yupeng Liu, Xiaowei Pei, Feng Zhou
Semi-interpenetrated polyvinyl alcohol polymer networks (SIPNs) were prepared by integrating various charged components into polyvinyl alcohol polymer. Contact angle measurement, attenuated total reflection Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and tensile tests were used to characterize the physicochemical properties of the prepared SIPNs. To investigate the contribution of charges to marine antifouling, the adhesion behaviors of green algae Dunaliella tertiolecta and diatoms Navicula sp...
May 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28477173/shared-epizoic-taxa-and-differences-in-diatom-community-structure-between-green-turtles-chelonia-mydas-from-distant-habitats
#4
Roksana Majewska, Bart Van de Vijver, Ali Nasrolahi, Maryam Ehsanpour, Majid Afkhami, Federico Bolaños, Franco Iamunno, Mario Santoro, Mario De Stefano
The first reports of diatoms growing on marine mammals date back to the early 1900s. However, only recently has direct evidence been provided for similar associations between diatoms and sea turtles. We present a comparison of diatom communities inhabiting carapaces of green turtles Chelonia mydas sampled at two remote sites located within the Indian (Iran) and Atlantic (Costa Rica) Ocean basins. Diatom observations and counts were carried out using scanning electron microscopy. Techniques involving critical point drying enabled observations of diatoms and other microepibionts still attached to sea turtle carapace and revealed specific aspects of the epizoic community structure...
May 6, 2017: Microbial Ecology
https://www.readbyqxmd.com/read/28475985/long-alkyl-chain-imidazolium-ionic-liquids-antibiofilm-activity-against-phototrophic-biofilms
#5
G Kiran Kumar Reddy, Y V Nancharaiah, V P Venugopalan
Biofilm formation is problematic and hence undesirable in medical and industrial settings. In addition to bacteria, phototrophic organisms are an integral component of biofilms that develop on surfaces immersed in natural waters. 1-Alkyl-3-methyl imidazolium ionic liquids (IL) with varying alkyl chain length were evaluated for their influence on the formation of monospecies (Navicula sp.) and multispecies biofilms under phototrophic conditions. An IL with a long alkyl side chain, 1-hexadecyl-3-methylimidaazolium chloride ([C16(MIM)][Cl]) retarded growth, adhesion and biofilm formation of Navicula sp...
April 23, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28432510/epilithic-diatom-assemblages-and-their-relationships-with-environmental-variables-in-the-nil%C3%A3-fer-stream-basin-bursa-turkey
#6
Didem Karacaoğlu, Nurhayat Dalkıran
Patterns of epilithic diatom species distribution in relation to environmental variables from 12 sampling sites on the main stream and some of its tributaries in the Nilüfer Stream Basin were determined using multivariate statistical techniques. The stream basin has been heavily influenced by anthropogenic effects. The upper part of the basin that is distant from pollution sources mostly has a spring water quality, while the lower part where the stream flows through the urban area and receives domestic and industrial wastewater has a quite low quality...
May 2017: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/28429593/model-amphiphilic-block-copolymers-with-tailored-molecular-weight-and-composition-in-pdms-based-films-to-limit-soft-biofouling
#7
Brandon M Wenning, Elisa Martinelli, Sophie Mieszkin, John A Finlay, Daniel Fischer, James A Callow, Maureen E Callow, Amanda K Leonardi, Christopher K Ober, Giancarlo Galli
A set of controlled surface composition films was produced utilizing amphiphilic block copolymers dispersed in a cross-linked poly(dimethylsiloxane) network. These block copolymers contained oligo(ethylene glycol) (PEGMA) and fluoroalkyl (AF6) side chains in selected ratios and molecular weights to control surface chemistry including antifouling and fouling-release performance. Such properties were assessed by carrying out assays using two algae, the green macroalga Ulva linza (favors attachment to polar surfaces) and the unicellular diatom Navicula incerta (favors attachment to nonpolar surfaces)...
May 2, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28374061/spatio-temporal-variations-of-marine-biofilm-communities-colonizing-artificial-substrata-including-antifouling-coatings-in-contrasted-french-coastal-environments
#8
Jean-François Briand, Aude Barani, Cédric Garnier, Karine Réhel, Félix Urvois, Christophe LePoupon, Agnès Bouchez, Didier Debroas, Christine Bressy
Surface colonization in seawater first corresponds to the selection of specific microbial biofilm communities. By coupling flow cytometry, microscopy and high throughput sequencing (HTS, 454 pyrosequencing) with artificial surfaces and environmental analyses, we intend to identify the contribution of biofilm community drivers at two contrasted French sites, one temperate and eutrophic (Lorient, Atlantic coast) and the other at a mesotrophic but highly contaminated bay (Toulon, North-Western Mediterranean Sea)...
April 3, 2017: Microbial Ecology
https://www.readbyqxmd.com/read/28369472/diversity-of-co2-concentrating-mechanisms-and-responses-to-co2-concentration-in-marine-and-freshwater-diatoms
#9
Romain Clement, Erik Jensen, Laura Prioretti, Stephen C Maberly, Brigitte Gontero
The presence of CO2-concentrating mechanisms (CCMs) is believed to be one of the characteristics that allows diatoms to thrive in many environments and to be major contributors to global productivity. Here, the type of CCM and the responses to variable CO2 concentration were studied in marine and freshwater diatoms. At 400 ppm, there was a large diversity in physiological and biochemical mechanisms among the species. While Phaeodactylum tricornutum mainly used HCO3-, Thalassiosira pseudonana mainly used CO2...
March 27, 2017: Journal of Experimental Botany
https://www.readbyqxmd.com/read/28270054/marine-anti-biofouling-efficacy-of-amphiphilic-poly-coacrylate-grafted-pdmse-effect-of-graft-molecular-weight
#10
Cary A Kuliasha, John A Finlay, Sofia C Franco, Anthony S Clare, Shane J Stafslien, Anthony B Brennan
There is currently strong motivation due to ecological concerns to develop effective anti-biofouling coatings that are environmentally benign, durable, and stable for use by the maritime industry. The antifouling (AF) and fouling-release (FR) efficacy of amphiphilic, charged copolymers composed of ~52% acrylamide, ~34% acrylic acid, and ~14% methyl acrylate grafted to poly(dimethyl siloxane) (PDMSe) surfaces were tested against zoospores of the green alga Ulva linza and the diatom Navicula incerta. The biofouling response to molecular weight variation was analyzed for grafts ranging from ~100 to 1,400 kg mol(-1), The amphiphilic coatings showed a marked improvement in the FR response, with a 55% increase in the percentage removal of diatoms and increased AF efficacy, with 92% reduction in initial attachment density of zoospores, compared to PDMSe controls...
March 2017: Biofouling
https://www.readbyqxmd.com/read/28214648/toxicity-degradation-and-metabolic-fate-of-ibuprofen-on-freshwater-diatom-navicula-sp
#11
Tengda Ding, Mengting Yang, Junmin Zhang, Bo Yang, Kunde Lin, Juying Li, Jay Gan
Ibuprofen (IBU) is one of the most widely used and frequently detected human pharmaceuticals in aquatic environment. However, the toxicity of IBU on diatom and its fate remain still unkown. In the present study, the toxicity of IBU on the diatom was evaluated by the algal growth rate, the chlorophyll-a and carotenoids contents. The degradation of IBU including in particular the potential for the formation of incomplete degradation products was also explored. Biochemical characteristics of Navicula sp. were significantly inhibited at IBU concentrations up to 50mgL(-1) after 10days of exposure...
February 6, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28125065/chytridiomycosis-of-marine-diatoms-the-role-of-stress-physiology-and-resistance-in-parasite-host-recognition-and-accumulation-of-defense-molecules
#12
Bettina Scholz, Frithjof C Küpper, Wim Vyverman, Halldór G Ólafsson, Ulf Karsten
Little is known about the role of chemotaxis in the location and attachment of chytrid zoospores to potential diatom hosts. Hypothesizing that environmental stress parameters affect parasite-host recognition, four chytrid-diatom tandem cultures (Chytridium sp./Navicula sp., Rhizophydium type I/Nitzschia sp., Rhizophydium type IIa/Rhizosolenia sp., Rhizophydium type IIb/Chaetoceros sp.) were used to test the chemotaxis of chytrid zoospores and the presence of potential defense molecules in a non-contact-co-culturing approach...
January 25, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28117130/chlorination-induced-damage-and-recovery-in-marine-diatoms-assay-by-sytox%C3%A2-green-staining
#13
Srinivas Venkatnarayanan, P Sriyutha Murthy, Yarlagadda V Nancharaiah, Ramalingam Kirubagaran, Vayalam P Venugopalan
Phytoplankton entrained into cooling water systems of coastal power stations are subjected to acute chemical stress due to biocides (chlorine) used for biofouling control. They are subsequently released into the environment, where they may survive/recover or succumb. Experiments were conducted to evaluate the susceptibility of a centric (Chaetoceros lorenzianus) and pennate (Navicula sp.) diatom to in-plant administered concentrations of chlorine (0.2-0.5mg/L, TRO). Viability of cells exposed to chlorine was assessed by SYTOX® Green fluorimetry and was compared with other conventional end points like total cell counts, chlorophyll a content and cellular autofluorescence...
January 20, 2017: Marine Pollution Bulletin
https://www.readbyqxmd.com/read/28013476/live-diatoms-as-indicators-of-urban-stormwater-runoff
#14
Nadia D Gillett, Maggie E Oudsema, Alan D Steinman
Diatom bioassessment of streams/rivers does not distinguish between live (cells with intact chloroplasts) and dead (empty cells) individuals, even though most diatom samples collected from the field will be composed of a mixture of both. This study aimed to evaluate whether percentage of live diatoms (PLD), live diatom density and chlorophyll a, and diatom species compositions can be used as indicators of hydrologic disturbance in an urban stream. We deployed artificial substrates on a monthly basis and collected periphyton samples weekly over the course of one calendar year (n = 182) in three tributaries of urbanized Ruddiman Creek (Michigan, USA)...
January 2017: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/27902175/spontaneous-and-bilateral-avascular-necrosis-of-the-navicula-m%C3%A3-ller-weiss-disease
#15
Erdem Aktaş, Tacettin Ayanoğlu, Yasin Hatipoğlu, Ulunay Kanatlı
Although, trauma, foot deformity (pesplanovalgus), systemic diseases such as diabetes mellitus and lupus, drugs (steroids, antineoplastic) and excessive alcohol consumption have all been accused in the etiology of avascular necrosis of the tarsal bones, spontaneous avascular necrosis of the navicular bone, especially in adults, is a rare entity. In this article, we report a 50-year-old female patient with bilateral, spontaneous avascular necrosis of the navicular bone and related severe talonavicular arthrosis...
December 2016: Eklem Hastalıkları Ve Cerrahisi, Joint Diseases & related Surgery
https://www.readbyqxmd.com/read/27810541/chitosan-zinc-oxide-nanocomposite-coatings-for-the-prevention-of-marine-biofouling
#16
Laila Al-Naamani, Sergey Dobretsov, Joydeep Dutta, J Grant Burgess
Marine biofouling is a worldwide problem affecting maritime industries. Global concerns about the high toxicity of antifouling paints have highlighted the need to develop less toxic antifouling coatings. Chitosan is a natural polymer with antimicrobial, antifungal and antialgal properties that is obtained from partial deacetylation of crustacean waste. In the present study, nanocomposite chitosan-zinc oxide (chitosan-ZnO) nanoparticle hybrid coatings were developed and their antifouling activity was tested...
February 2017: Chemosphere
https://www.readbyqxmd.com/read/27696809/fouling-release-performance-of-silicone-oil-modified-siloxane-polyurethane-coatings
#17
Teluka P Galhenage, Dylan Hoffman, Samantha D Silbert, Shane J Stafslien, Justin Daniels, Tatjana Miljkovic, John A Finlay, Sofia C Franco, Anthony S Clare, Brian T Nedved, Michael G Hadfield, Dean E Wendt, Grant Waltz, Lenora Brewer, Serena Lay-Ming Teo, Chin-Sing Lim, Dean C Webster
The effect of incorporation of silicone oils into a siloxane-polyurethane fouling-release coatings system was explored. Incorporation of phenylmethyl silicone oil has been shown to improve the fouling-release performance of silicone-based fouling-release coatings through increased interfacial slippage. The extent of improvement is highly dependent upon the type and composition of silicone oil used. The siloxane-polyurethane (SiPU) coating system is a tough fouling-release solution, which combines the mechanical durability of polyurethane while maintaining comparable fouling-release performance with regard to commercial standards...
October 3, 2016: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/27639474/combined-in-situ-effects-of-metals-and-nutrients-on-marine-biofilms-shifts-in-the-diatom-assemblage-structure-and-biological-traits
#18
M D Belando, A Marín, M Aboal, A J García-Fernández, L Marín-Guirao
The effects of multiple stressors on marine diatom assemblages are still poorly understood. The interactive effects of metals and nutrients were assessed in two coastal biofilms grown at a reference site and a historically contaminated site. The biofilms were exposed in situ to pulse exposures of metals (Zn and Pb) and nutrients (N and P) individually and in combination to mimic patterns of discharge in the study area. The reference community's structure (composition and abundance of taxa) was modified after metals and/or nutrients exposure, but each stressor acted in different way...
September 15, 2016: Science of the Total Environment
https://www.readbyqxmd.com/read/27553944/phytoplankton-abundance-and-structure-as-indicator-of-water-quality-in-the-drainage-system-of-the-burullus-lagoon-southern-mediterranean-coast-egypt
#19
Hala Yassin El-Kassas, Samiha Mahmoud Gharib
This study represents the first detailed account of phytoplankton community structure and seasonal succession in eight drain sites and the Brimbal Canal influx into the Burullus Lagoon. The phytoplankton characteristics were studied based on the data collected seasonally over 4 years, from summer 2012 to spring 2016. Various indices such as Palmer's and Shannon's biotic indices were used for the assessment of the water quality of the different drains. There were a total of 194 species belonging to 65 genera and 6 groups: Bacillariophyceae (76 species), Chlorophyceae (59 species), Cyanophyceae (30 species), Euglenophyceae (25 species), Dinophyceae (3 species), and Xanthophyceae (1 species)...
September 2016: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/27507418/effects-of-antibiotics-on-the-growth-and-physiology-of-chlorophytes-cyanobacteria-and-a-diatom
#20
Jiahua Guo, Katherine Selby, Alistair B A Boxall
The occurrence of antibiotics in surface waters has been reported worldwide with concentrations ranging from ng L(-1) to low µg L(-1) levels. During environmental risk assessments, effects of antibiotics on algal species are assessed using standard test protocols (e.g., the OECD 201 guideline), where the cell number endpoint is used as a surrogate for growth. However, the use of photosynthetic related endpoints, such as oxygen evolution rate, and the assessment of effects on algal pigments could help to inform our understanding of the impacts of antibiotics on algal species...
November 2016: Archives of Environmental Contamination and Toxicology
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