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https://www.readbyqxmd.com/read/28646231/inter-annual-variability-of-transparent-exopolymer-particles-in-the-arctic-ocean-reveals-high-sensitivity-to-ecosystem-changes
#1
Anja Engel, Judith Piontek, Katja Metfies, Sonja Endres, Pim Sprong, Ilka Peeken, Steffi Gäbler-Schwarz, Eva-Maria Nöthig
Transparent exopolymer particles (TEP) are a class of marine gel particles and important links between surface ocean biology and atmospheric processes. Derived from marine microorganisms, these particles can facilitate the biological pumping of carbon dioxide to the deep sea, or act as cloud condensation and ice nucleation particles in the atmosphere. Yet, environmental controls on TEP abundance in the ocean are poorly known. Here, we investigated some of these controls during the first multiyear time-series on TEP abundance for the Fram Strait, the Atlantic gateway to the Central Arctic Ocean...
June 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28645053/assessment-of-imaging-in-flow-system-flowcam-for-systematic-ballast-water-management
#2
Leonardo Romero-Martínez, Cees van Slooten, Enrique Nebot, Asunción Acevedo-Merino, Louis Peperzak
Assessing the disinfection of ballast water and its compliance with international standards requires determining the size, viability, and concentration of planktonic organisms. The FlowCAM (Flow Cytometer and Microscope) is an Imaging Flow Cytometry designed to obtain the particle concentration, images, and quantitative morphologic information. The objective in this paper is to establish the basis for transforming the FlowCAM from being a laboratory analyzer into a tool for systematic monitoring of ballast water...
June 20, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28644993/long-term-toxicity-of-surface-charged-polystyrene-nanoplastics-to-marine-planktonic-species-dunaliella-tertiolecta-and-artemia-franciscana
#3
E Bergami, S Pugnalini, M L Vannuccini, L Manfra, C Faleri, F Savorelli, K A Dawson, I Corsi
Plastic pollution has been globally recognized as a critical issue for marine ecosystems and nanoplastics constitute one of the last unexplored areas to understand the magnitude of this threat. However, current difficulties in sampling and identifying nano-sized debris make hard to assess their occurrence in marine environment. Polystyrene nanoparticles (PS NPs) are largely used as nanoplastics in ecotoxicological studies and although acute exposures have been already investigated, long-term toxicity on marine organisms is unknown...
June 15, 2017: Aquatic Toxicology
https://www.readbyqxmd.com/read/28644912/biofilm-formation-and-disinfectant-resistance-of-salmonella-spp-in-mono-and-dual-species-with-pseudomonas-aeruginosa
#4
Xinyi Pang, Yishan Yang, Hyun-Gyun Yuk
AIMS: This study aimed to evaluate the biofilm formation and disinfectant resistance of Salmonella cells in mono- and dual-species biofilms with Pseudomonas aeruginosa, and to investigate the role of extracellular polymeric substances (EPS) in protection of biofilms against disinfection treatment. METHODS AND RESULTS: The populations of Salmonella in mono- or dual-species biofilms with P. aeruginosa on stainless steel (SS) coupons were determined before and after exposure to commercial disinfectant, 50 μg ml(-1) chlorine or 200 μg ml(-1) Ecolab(®) Whisper(™) V (a blend of four effective quaternary ammonium compounds)...
June 23, 2017: Journal of Applied Microbiology
https://www.readbyqxmd.com/read/28642753/suhb-regulates-the-motile-sessile-switch-in-pseudomonas-aeruginosa-through-the-gac-rsm-pathway-and-c-di-gmp-signaling
#5
Kewei Li, Guangjian Yang, Alexander B Debru, Pingping Li, Li Zong, Peizhen Li, Teng Xu, Weihui Wu, Shouguang Jin, Qiyu Bao
Many Pseudomonas aeruginosa virulence traits that contribute to human infections are accepted as being associated with its environmental lifestyle. Therefore, identifying the molecular mechanisms that govern the lifestyle choice is of high significance. We previously reported that a mutation in suhB results in a decrease in swimming motility and increased biofilm formation compared to the wild-type strain. Yet, little is known about how this occurs. In this study, we demonstrated that SuhB inversely regulates motility and biofilm formation through the GacA-RsmY/Z-RsmA cascade...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28642103/chimeric-analogs-of-human-%C3%AE-defensin-1-and-%C3%AE-defensin-disrupt-pre-established-bacterial-biofilms
#6
Basil Mathew, Sudar Olli, Ankeeta Guru, Ramakrishanan Nagaraj
Antibiofilm activity of several human defensin analogs that have the ability to kill planktonic bacteria, against pre-established biofilms of Escherichia coli MG1655 and Staphylococcus aureus NCTC 8530 were examined. Linear and linear fatty acylated analogs did not show any activity while disulfide constrained analogs disrupted pre-established S. aureus biofilms. Chimeric analogs of human β-defensin 1 and θ-defensin, hBTD-1 and [d]hBTD-1 were highly active against S. aureus biofilms. Among the analogs tested, only the d-enantiomer [d]hBTD-1 showed activity against E...
June 12, 2017: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28641671/occurrence-of-aerobic-and-anaerobic-bacteria-in-the-consumer-end-of-a-water-distribution-system
#7
Süleyman Hoca, Miray Üstüntürk-Onan, Esra Ilhan-Sungur
  In this study, mixed species biofilm formation including sulphate-reducing bacteria (SRB) on polypropylene surface and bacteriology of network water were investigated in a model water distribution system during a nine-month period. Water and biofilm samples were analyzed for the enumeration of aerobic heterotrophic bacteria (AHB), anaerobic heterotrophic bacteria (ANHB) and SRB. The number of live/dead bacteria was also analyzed by epifluorescence microscopy. In addition, extracellular polysaccharide substances (EPS) extraction, carbohydrate analysis and scanning electron microscope observation were performed...
July 1, 2017: Water Environment Research: a Research Publication of the Water Environment Federation
https://www.readbyqxmd.com/read/28636078/microbial-lipopeptide-production-and-purification-bioprocesses-current-progress-and-future-challenges
#8
REVIEW
François Coutte, Didier Lecouturier, Krasimir Dimitrov, Jean-Sébastien Guez, Frank Delvigne, Pascal Dhulster, Philippe Jacques
Lipopeoptides are amphiphilic compounds combining interesting physicochemical properties and biological activities. Due to their high foaming capacity in aerated bioreactor, the development of scalable bioprocesses for their production is a major bottleneck. In addition, the genes involved in the biosynthesis of these lipopeptides are mainly regulated by the quorum sensing, a global regulatory mechanism depending on cell density and known to be activated in biofilms. Several approaches have thus been considered in literature taking into account two criteria, on one side, to favor, control or avoid foam formation and on the other side, to use planktonic or immobilized (biofilm) cells...
June 21, 2017: Biotechnology Journal
https://www.readbyqxmd.com/read/28633052/disinfection-efficiencies-of-sage-and-spearmint-essential-oils-against-planktonic-and-biofilm-staphylococcus-aureus-cells-in-comparison-with-sodium-hypochlorite
#9
Dimitrios Vetas, Eleni Dimitropoulou, Gregoria Mitropoulou, Yiannis Kourkoutas, Efstathios Giaouris
Staphylococcus aureus causes human infections and foodborne intoxications. This study explored the potential antibacterial actions of sage and spearmint essential oils (EOs) against both its planktonic and biofilm cells, in comparison with sodium hypochlorite (NaOCl), a commonly applied chemical sanitizer. Initially, the minimum inhibitory and bactericidal concentrations (MICs, MBCs) of each plant mixture were determined against planktonic cultures, following growth at 30°C for 24h. Stationary phase planktonic bacteria were then individually exposed for 6min to either each EO (applied at 1-2×MBC; 2...
June 8, 2017: International Journal of Food Microbiology
https://www.readbyqxmd.com/read/28631440/recognition-cascade-and-metabolite-transfer-in-a-marine-bacteria-phytoplankton-model-system
#10
Bryndan P Durham, Stephen P Dearth, Shalabh Sharma, Shady A Amin, Christa B Smith, Shawn R Campagna, E Virginia Armbrust, Mary Ann Moran
The trophic linkage between marine bacteria and phytoplankton in the surface ocean is a key step in the global carbon cycle, with almost half of marine primary production transformed by heterotrophic bacterioplankton within hours to weeks of fixation. Early studies conceptualized this link as the passive addition and removal of organic compounds from a shared seawater reservoir. Here we analyzed transcript and intracellular metabolite patterns in a two-member model system and found that the presence of a heterotrophic bacterium induced a potential recognition cascade in a marine phytoplankton species that parallels better-understood vascular plant response systems...
June 19, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28630204/a-low-molecular-weight-alginate-oligosaccharide-disrupts-pseudomonal-microcolony-formation-and-enhances-antibiotic-effectiveness
#11
Manon F Pritchard, Lydia C Powell, Alison A Jack, Kate Powell, Konrad Beck, Hannah Florance, Julian Forton, Philip D Rye, Arne Dessen, Katja E Hill, David W Thomas
In chronic respiratory disease the formation of dense, 3-dimensional 'micro colonies' by Pseudomonas aeruginosa within the airway plays an important role in contributing to resistance to treatment. An in vitro biofilm model of pseudomonal microcolony formation using artificial sputum (AS) medium was established to study the effects of low molecular weight alginate oligomers (OligoG CF-5/20) on pseudomonal growth, microcolony formation and the efficacy of colistin. The studies employed clinical cystic fibrosis (CF) isolates (n=3) and reference non-mucoid and mucoid multi-drug resistant (MDR) CF isolates (n=7)...
June 19, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28629011/chitosan-nanoparticles-as-alternative-anti-staphylococci-agents-bactericidal-antibiofilm-and-antiadhesive-effects
#12
E M Costa, S Silva, S Vicente, C Neto, P M Castro, M Veiga, R Madureira, F Tavaria, M M Pintado
Chitosan is a biocompatible, bioactive, non-toxic polymer that due to these characteristics has been widely used as a carrier for targeted delivery of bioactive molecules. In recent years, and considering that chitosan has a strong antimicrobial potential, the scientific community's focus has shifted onto the possible antimicrobial activity of chitosan nanoparticles. With this in mind, the aim of this work was to produce low molecular weight chitosan nanoparticles, through the ionic gelation method and characterize their potential biological activity against three staphylococci (MSSA, MRSA and MRSE) in planktonic and sessile environments...
October 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28628993/the-impact-of-silver-nanoparticles-on-marine-plankton-dynamics-dependence-on-coating-size-and-concentration
#13
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/28628486/inactivation-of-bacterial-biofilms-by-visible-light-activated-unmodified-zno-nanorods
#14
Kristina Aponiene, Tomas Serevičius, Zivile Luksiene, Saulius Jursenas
Various zinc oxide (ZnO) nanostructures are widely used for photocatalytic antibacterial applications. Since ZnO possess a wide bandgap, it is believed that only UV light may efficiently assist bacterial inactivation and diverse crystal lattice modifications should be applied in order to narrow the bandgap for efficient visible light absorption. In this work we show that even unmodified ZnO nanorods grown by aqueous chemical growth technique were found to possess intrinsic defects which can be activated by visible light ( = 405 nm) and successfully applied for total inactivation of various highly resistant bacterial biofilms rather than more sensitive planktonic bacteria...
June 19, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28625778/analysis-of-phytoplankton-assemblage-structure-in-the-mediterranean-sea-based-on-high-throughput-sequencing-of-partial-18s-rrna-sequences
#15
Antonella Penna, Silvia Casabianca, Antonio Fernandez Guerra, Cristiano Vernesi, Michele Scardi
Studying taxonomic and ecological diversity of phytoplankton assemblages is often difficult because morphological analysis cannot provide a complete description of their composition. Therefore, more robust and feasible approaches have to be chosen to elucidate the interactions between environmental and human pressures and phytoplankton assemblages. The Ocean Sampling Day (OSD) allowed collecting seawater samples from a wide range of oceanic regions including the Mediterranean Sea. In this study, a total of 754,167 V4-18S ribosomal DNA (rDNA) metabarcodes derived from 20 plankton samples collected at 19 sampling sites across the coastal areas of the Mediterranean Sea were analyzed to explore the relationships between phytoplankton assemblages' composition, sub-regional environmental features and human pressures...
June 15, 2017: Marine Genomics
https://www.readbyqxmd.com/read/28625616/modelling-explicit-tides-in-the-indonesian-seas-an-important-process-for-surface-sea-water-properties
#16
Dwiyoga Nugroho, Ariane Koch-Larrouy, Philippe Gaspar, Florent Lyard, Guillaume Reffray, Benoit Tranchant
Very intense internal tides take place in Indonesian seas. They dissipate and affect the vertical distribution of temperature and currents, which in turn influence the survival rates and transports of most planktonic organisms at the base of the whole marine ecosystem. This study uses the INDESO physical model to characterize the internal tides spatio-temporal patterns in the Indonesian Seas. The model reproduced internal tide dissipation in agreement with previous fine structure and microstructure observed in-situ in the sites of generation...
June 16, 2017: Marine Pollution Bulletin
https://www.readbyqxmd.com/read/28623024/functional-diversity-of-aquatic-ciliates
#17
REVIEW
Thomas Weisse
This paper first reviews the concept of functional diversity in general terms and then applies it to free-living aquatic ciliates. Ciliates are extremely versatile organisms and display an enormous functional diversity as key elements of pelagic food webs, acting as predators of bacteria, algae, other protists and even some metazoans. Planktonic ciliates are important food for zooplankton, and mixotrophic and functionally autotrophic species may significantly contribute to primary production in the ocean and in lakes...
April 13, 2017: European Journal of Protistology
https://www.readbyqxmd.com/read/28622460/antifungal-activity-of-tyrosol-and-farnesol-used-in-combination-against-candida-species-in-the-planktonic-state-or-forming-biofilms
#18
Douglas Roberto Monteiro, Laís Salomão Arias, Renan Aparecido Fernandes, Lucas Fernando Deszo da Silva, Manoel Olavo Valentim Fernandes de Castilho, Thaís Oliveira da Rosa, Ana Paula Miranda Vieira, Fabiana Gouveia Straioto, Débora Barros Barbosa, Alberto Carlos Botazzo Delbem
AIM: This study examined the antifungal activity of the combination of tyrosol and farnesol against Candida albicans and Candida glabrata in the planktonic state or forming biofilms. METHODS AND RESULTS: The effect of drug association against Candida planktonic cells was assessed by the fractional inhibitory concentration index. Mono and dual-species biofilms were developed (24 h) and the compounds, applied during 3 days, with 2 daily treatments of 1 minute each...
June 16, 2017: Journal of Applied Microbiology
https://www.readbyqxmd.com/read/28620360/cytr-homolog-of-pectobacterium-carotovorum-subsp-carotovorum-controls-air-liquid-biofilm-formation-by-regulating-multiple-genes-involved-in-cellulose-production-c-di-gmp-signaling-motility-and-type-iii-secretion-system-in-response-to-nutritional-and-environmental
#19
M M Haque, M M H Oliver, Kamrun Nahar, Mohammad Z Alam, Hisae Hirata, Shinji Tsuyumu
Pectobacterium carotovorum subsp. carotovorum [Pcc (formerly Erwinia carotovora subsp. carotovora)] PC1 causes soft-rot disease in a wide variety of plant species by secreting multiple pathogenicity-related traits. In this study, regulatory mechanism of air-liquid (AL) biofilm formation was studied using a cytR homolog gene deletion mutant (ΔcytR) of Pcc PC1. Compared to the wild type (Pcc PC1), the ΔcytR mutant produced fragile and significantly (P < 0.001) lower amounts of AL biofilm on salt-optimized broth plus 2% glycerol (SOBG), yeast peptone dextrose adenine, and also on King's B at 27°C after 72 h incubation in static condition...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28618357/visualisation-study-on-pseudomonas-migulae-an-1-transport-in-saturated-porous-media
#20
Dan Qu, Hejun Ren, Rui Zhou, Yongsheng Zhao
Influence of granular size and groundwater flow rate on transport of Pseudomonas migulae AN-1 in saturated porous media was non-invasively and visually investigated with a novel imaging technique based on our previously established green fluorescent protein-tagging approach. AN-1 was transported faster than water was. The finer the media were, the greater the enhancement of bacterial velocity was. Mass recovery (MR) increased, while deposition rate coefficient (Kc) decreased, with increasing granular size. Similar and linear trends of MR and Kc, respectively, were quantitatively observed with increasing water flow rate...
June 7, 2017: Water Research
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