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https://www.readbyqxmd.com/read/28548660/transcriptomic-and-micrornaomic-profiling-reveals-multi-faceted-mechanisms-to-cope-with-phosphate-stress-in-a-dinoflagellate
#1
Xinguo Shi, Xin Lin, Ling Li, Meizhen Li, Brian Palenik, Senjie Lin
Although gene regulation can occur at both transcriptional and epigenetic (microRNA) levels, combined transcriptomic and microRNAomic responses to environmental stress are still largely unexplored for marine plankton. Here, we conducted transcriptome and microRNAome sequencing for Prorocentrum donghaiense to understand the molecular mechanisms by which this dinoflagellate copes with phosphorus (P) deficiency. Under P-depleted conditions, G1/S specific cyclin gene was markedly downregulated, consistent with growth inhibition, and genes related to dissolved organic phosphorus (DOP) hydrolysis, carbon fixation, nitrate assimilation, glycolysis, and cellular motility were upregulated...
May 26, 2017: ISME Journal
https://www.readbyqxmd.com/read/28547211/sheldon-spectrum-and-the-plankton-paradox-two-sides-of-the-same-coin-a-trait-based-plankton-size-spectrum-model
#2
José A Cuesta, Gustav W Delius, Richard Law
The Sheldon spectrum describes a remarkable regularity in aquatic ecosystems: the biomass density as a function of logarithmic body mass is approximately constant over many orders of magnitude. While size-spectrum models have explained this phenomenon for assemblages of multicellular organisms, this paper introduces a species-resolved size-spectrum model to explain the phenomenon in unicellular plankton. A Sheldon spectrum spanning the cell-size range of unicellular plankton necessarily consists of a large number of coexisting species covering a wide range of characteristic sizes...
May 25, 2017: Journal of Mathematical Biology
https://www.readbyqxmd.com/read/28546427/spermidine-promotes-bacillus-subtilis-biofilm-formation-by-activating-expression-of-the-matrix-regulator-slrr
#3
Laura Hobley, Bin Li, Jennifer L Wood, Sok-Ho Kim, Jacinth Naidoo, Ana Sofia Ferreira, Maxim Khomutov, Alexey Khomutov, Nicola R Stanley-Wall, Anthony J Michael
Ubiquitous polyamine spermidine is not required for normal planktonic growth of Bacillus subtilis but is essential for robust biofilm formation. However, the structural features of spermidine required for B. subtilis biofilm formation are unknown and so are the molecular mechanisms of spermidine-stimulated biofilm development. We report here that in a spermidine-deficient B. subtilis mutant, the structural analogue norspermidine, but not homospermidine, restored biofilm formation. Intracellular biosynthesis of another spermidine analogue, aminopropylcadaverine, from exogenously supplied homoagmatine also restored biofilm formation...
May 25, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28545863/the-impact-of-dissolved-inorganic-nitrogen-and-phosphorous-on-responses-of-microbial-plankton-to-the-texas-city-y-oil-spill-in-galveston-bay-texas-usa
#4
Alicia K Williams, Hernando P Bacosa, Antonietta Quigg
Ongoing bioremediation research seeks to promote naturally occurring microbial polycyclic aromatic hydrocarbon (PAH) degradation during and after oil spill events. However, complex relationships among functionally different microbial groups, nutrients and PAHs remain unconstrained. We conducted a surface water survey and corresponding nutrient amendment bioassays following the Texas City "Y" oil spill in Galveston Bay, Texas. Resident microbial groups, defined as either heterotrophic or autotrophic were enumerated by flow cytometry...
May 22, 2017: Marine Pollution Bulletin
https://www.readbyqxmd.com/read/28543439/metagenomic-profiling-of-the-microbial-freshwater-communities-in-two-bulgarian-reservoirs
#5
Ivan Iliev, Galina Yahubyan, Mariana Marhova, Elena Apostolova, Mariyana Gozmanova, Gana Gecheva, Sonya Kostadinova, Angelina Ivanova, Vesselin Baev
Microorganisms inhabiting freshwater environments are an integral part of the aquatic ecosystems. Very few data are available regarding the profiles of the microbial communities in the reservoirs in Bulgaria, despite their key role in the biogeochemical processes. In the present study, we provide the first comprehensive metagenomic analysis on the planktonic bacterial diversity of two large and economically important Bulgarian reservoirs (Batak and Tsankov Kamak) using next-generation sequencing of 16S ribosomal RNA gene (16S rRNA)...
May 22, 2017: Journal of Basic Microbiology
https://www.readbyqxmd.com/read/28542872/classification-of-planctonema-like-algae-including-a-new-genus-planctonemopsis-gen-nov-a-new-species-planctonema-gelatinosum-sp-nov-and-a-reinstated-genus-psephonema-trebouxiophyceae-chlorophyta
#6
Xudong Liu, Huan Zhu, Benwen Liu, Guoxiang Liu, Zhengyu Hu
Planctonema-like species consist of planktonic green algae and are found throughout the world. Their characteristic morphology, which includes short and slender filaments consisting of side-by-side or distant cylindrical cells enclosed in a fine and hyaline sheath, makes them easily distinguishable. To date, Planctonema lauterbornii was the only taxon accepted for this group. However, descriptions from different materials have revealed notable morphological differences, including the presence/absence of a pyrenoid, a mucilage sheath and an apical thickening of the cell wall...
May 19, 2017: Journal of Phycology
https://www.readbyqxmd.com/read/28540567/-the-significance-of-biofilm-for-the-treatment-of-infections-in-orthopedic-surgery-2017-update
#7
REVIEW
C Scheuermann-Poley, C Wagner, J Hoffmann, A Moter, C Willy
BACKGROUND: The increase in endoprosthetic and osteosynthetic surgical treatment is associated with a simultaneous increase in implant-associated infections (surgical site infections, SSI). Biofilms appear to play a significant role in the diagnosis and treatment of these infections and heavily contaminated wounds. This article aims to provide a current overview of biofilm and its relevance in orthopedic surgery. MATERIALS AND METHODS: A computer-assisted literature search of MedLine (PubMed) was performed using key word combinations with "biofilm" (as of March 2017)...
May 24, 2017: Der Unfallchirurg
https://www.readbyqxmd.com/read/28539649/interspecies-interactions-reverse-the-hazard-of-antibiotics-exposure-a-plankton-community-study-on-responses-to-ciprofloxacin-hydrochloride
#8
Changyou Wang, Ziyang Wang, Yong Zhang, Rongguo Su
The ecotoxicological effects of Ciprofloxacin hydrochloride (CIP) were tested on population densities of plankton assemblages consisting of two algae (Isochrysis galbana and Platymonas subcordiformis) and a rotifer (Brachionus plicatilis). The I. galbana showed a significant decrease in densities when concentrations of CIP were above 2.0 mg L(-1) in single-species tests, while P. subcordiformis and B. plicatilis were stable in densities when CIP were less than10.0 mg L(-1). The equilibrium densities of I...
May 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28536559/new-functions-and-subcellular-localization-patterns-of-c-di-gmp-components-ggdef-domain-proteins-in-b-subtilis
#9
Patricia Bedrunka, Peter L Graumann
The universal and pleiotropic cyclic dinucleotide second messenger c-di-GMP is most prominently known to inversely regulate planktonic and sessile lifestyles of Gram-negative species. In the Gram-positive model organism Bacillus subtilis, intracellular c-di-GMP levels are modulated by a concise set of three diguanylate cylases (DgcK, DgcP, DgcW) and one phosphodiesterase (PdeH). Two recent studies have reported the negative influence of the c-di-GMP receptor DgrA (PilZ domain protein) on swarming motility indicating a conserved role of this second messenger across the bacterial domain...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28533519/ocean-acidification-compromises-a-planktic-calcifier-with-implications-for-global-carbon-cycling
#10
Catherine V Davis, Emily B Rivest, Tessa M Hill, Brian Gaylord, Ann D Russell, Eric Sanford
Anthropogenically-forced changes in ocean chemistry at both the global and regional scale have the potential to negatively impact calcifying plankton, which play a key role in ecosystem functioning and marine carbon cycling. We cultured a globally important calcifying marine plankter (the foraminifer, Globigerina bulloides) under an ecologically relevant range of seawater pH (7.5 to 8.3 total scale). Multiple metrics of calcification and physiological performance varied with pH. At pH > 8.0, increased calcification occurred without a concomitant rise in respiration rates...
May 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28533383/mechanosensing-of-shear-by-pseudomonas-aeruginosa-leads-to-increased-levels-of-the-cyclic-di-gmp-signal-initiating-biofilm-development
#11
Christopher A Rodesney, Brian Roman, Numa Dhamani, Benjamin J Cooley, Ahmed Touhami, Vernita D Gordon
Biofilms are communities of sessile microbes that are phenotypically distinct from their genetically identical, free-swimming counterparts. Biofilms initiate when bacteria attach to a solid surface. Attachment triggers intracellular signaling to change gene expression from the planktonic to the biofilm phenotype. For Pseudomonas aeruginosa, it has long been known that intracellular levels of the signal cyclic-di-GMP increase upon surface adhesion and that this is required to begin biofilm development. However, what cue is sensed to notify bacteria that they are attached to the surface has not been known...
May 22, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28532167/how-the-marine-biotoxins-affect-human-health
#12
Silvia Morabito, Serena Silvestro, Caterina Faggio
Several marine microalgae produce dangerous toxins very damaging to human health, aquatic ecosystems and coastal resources. These Harmful Algal Blooms (HABs) in recent decades seem greatly increased regarding frequency, severity and biogeographical level, causing serious health risks as a consequence of the consumption of contaminated seafood. Toxins can cause various clinically described syndromes, characterised by a wide range of symptoms: amnesic (ASP), diarrhoetic (DSP), azaspirazid (AZP), neurotoxic (NSP) and paralytic (PSP) shellfish poisonings and ciguatera fish poisoning...
May 22, 2017: Natural Product Research
https://www.readbyqxmd.com/read/28529864/allograft-bone-as-antibiotic-carrier
#13
REVIEW
Heinz Winkler, Peter Haiden
The treatment of chronic bone and joint infections is characterized by obstinate persistency of the causing microorganisms and resulting long term disability to patients, associated with remarkable costs for the health care system. Difficulties derive from biofilm formed on dead bone and eventual implants, with resistance against immunological defences and antimicrobial substances. Biofilm embedded bacteria require up to 1000 times the antibiotic concentration of planktonic bacteria for elimination. Systemic antibiotic treatment alone cannot provide the concentrations required and surgical intervention is always prerequisite for potentially providing a cure...
2017: J Bone Jt Infect
https://www.readbyqxmd.com/read/28527321/short-term-exposure-to-gold-nanoparticle-suspension-impairs-swimming-behavior-in-a-widespread-calanoid-copepod
#14
François-Gaël Michalec, Markus Holzner, Alexandre Barras, Anne-Sophie Lacoste, Loïc Brunet, Jae-Seong Lee, Christian Slomianny, Rabah Boukherroub, Sami Souissi
Calanoid copepods play an important role in the functioning of marine and brackish ecosystems. Information is scarce on the behavioral toxicity of engineered nanoparticles to these abundant planktonic organisms. We assessed the effects of short-term exposure to nonfunctionalized gold nanoparticles on the swimming behavior of the widespread estuarine copepod Eurytemora affinis. By means of three-dimensional particle tracking velocimetry, we reconstructed the trajectories of males, ovigerous and non-ovigerous females...
May 17, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28526851/characterization-of-trpa-channels-in-the-starfish-patiria-pectinifera-involvement-of-thermally-activated-trpa1-in-thermotaxis-in-marine-planktonic-larvae
#15
Shigeru Saito, Gen Hamanaka, Narudo Kawai, Ryohei Furukawa, Jun Gojobori, Makoto Tominaga, Hiroyuki Kaneko, Yoko Satta
The vast majority of marine invertebrates spend their larval period as pelagic plankton and are exposed to various environmental cues. Here we investigated the thermotaxis behaviors of the bipinnaria larvae of the starfish, Patiria pectinifera, in association with TRPA ion channels that serve as thermal receptors in various animal species. Using a newly developed thermotaxis assay system, we observed that P. pectinifera larvae displayed positive thermotaxis toward high temperatures, including toward temperatures high enough to cause death...
May 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28526497/mixed-species-biofilms-of-fusobacterium-necrophorum-and-porphyromonas-levii-impair-the-oxidative-response-of-bovine-neutrophils-in-vitro
#16
Joey S Lockhart, Andre G Buret, Howard Ceri, Douglas G Storey, Stefanie J Anderson, Douglas W Morck
Biofilms composed of anaerobic bacteria can result in persistent infections and chronic inflammation. Host immune cells have difficulties clearing biofilm-related infections and this can result in tissue damage. Neutrophils are a vital component of the innate immune system and help clear biofilms. The comparative neutrophilic response to biofilms versus planktonic bacteria remains incompletely understood, particularly in the context of mixed infections. The objective of this study was to generate mixed species anaerobic bacterial biofilms composed of two opportunistic pathogens, Fusobacterium necrophorum and Porphyromonas levii, and evaluate neutrophil responses to extracellular fractions from both biofilms and planktonic cell co-cultures of the same bacteria...
May 16, 2017: Anaerobe
https://www.readbyqxmd.com/read/28522534/21st-century-rise-in-anthropogenic-nitrogen-deposition-on-a-remote-coral-reef
#17
Haojia Ren, Yi-Chi Chen, Xingchen T Wang, George T F Wong, Anne L Cohen, Thomas M DeCarlo, Mira A Weigand, Horng-Sheng Mii, Daniel M Sigman
With the rapid rise in pollution-associated nitrogen inputs to the western Pacific, it has been suggested that even the open ocean has been affected. In a coral core from Dongsha Atoll, a remote coral reef ecosystem, we observe a decline in the (15)N/(14)N of coral skeleton-bound organic matter, which signals increased deposition of anthropogenic atmospheric N on the open ocean and its incorporation into plankton and, in turn, the atoll corals. The first clear change occurred just before 2000 CE, decades later than predicted by other work...
May 19, 2017: Science
https://www.readbyqxmd.com/read/28521545/silver-oxynitrate-an-efficacious-compound-for-the-prevention-and-eradication-of-dual-species-biofilms
#18
Joe A Lemire, Lindsay Kalan, Natalie Gugala, Alexandru Bradu, Raymond J Turner
Preventing and eradicating biofilms remains a challenge in clinical and industrial settings. Recently, the present authors demonstrated that silver oxynitrate (Ag7NO11) prevented and eradicated single-species planktonic and biofilm populations of numerous microbes at lower concentrations than other silver (Ag) compounds. Here, the antimicrobial and anti-biofilm efficacy of Ag7NO11 is elaborated by testing its in vitro activity against combinations of dual-species, planktonic and biofilm populations of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa...
May 19, 2017: Biofouling
https://www.readbyqxmd.com/read/28521511/effects-of-adaptation-to-carvacrol-on-staphylococcus-aureus-in-the-planktonic-and-biofilm-phases
#19
Antonia Nostro, Andreana Marino, Giovanna Ginestra, Luigina Cellini, Mara Di Giulio, Giuseppe Bisignano
The effect of exposure to sub-minimum inhibitory concentrations of carvacrol, for either 3-10 days, on direct (carvacrol) or cross-protection (cinnamaldehyde, eugenol, antibiotics) and the influence on planktonic and biofilm growth of four Staphylococcus aureus strains were reported. The sequential exposure to carvacrol resulted in a direct protection that was more evident in two of the four strains after 10 days. No significant cross-protection against cinnamaldehyde, eugenol and antibiotics was detected...
May 18, 2017: Biofouling
https://www.readbyqxmd.com/read/28520877/abundance-and-molecular-diversity-of-thraustochytrids-in-coastal-waters-of-southern-china
#20
Ying Liu, Purnima Singh, Yuanmei Liang, Jingjing Li, Ningdong Xie, Zhiquan Song, Maurycy Daroch, Keming Leng, Zackary I Johnson, Guangyi Wang
Thraustochytrids are unicellular fungi-like (heterotrophic) marine protists and have long been considered to play an important role in the biogeochemical cycles of the coastal oceans. However, the significance of their ecological functions and diversity in marine ecosystems remain largely unknown. In this report, we examined the spatial and temporal variations of planktonic thraustochytrids, their relationship with other environmental factors, and their diversity in the subtropical coastal waters of China. The abundance of planktonic thraustochytrids ranged from 2...
May 18, 2017: FEMS Microbiology Ecology
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