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https://www.readbyqxmd.com/read/29352081/expression-of-the-pseudomonas-aeruginosa-biofilm-antibiotic-resistance-gene-ndvb-requires-the-rpos-stationary-phase-sigma-factor
#1
Clayton W Hall, Aaron J Hinz, Luke B-P Gagnon, Li Zhang, Jean-Paul Nadeau, Sarah Copeland, Bratati Saha, Thien-Fah Mah
Chronic, biofilm-based bacterial infections are exceptionally difficult to eradicate due to the high degree of antibiotic recalcitrance exhibited by cells in biofilm communities. In the opportunistic pathogen Pseudomonas aeruginosa, biofilm recalcitrance is multifactorial and arises in part from the preferential expression of resistance genes in biofilms compared to exponential phase planktonic cells. One such mechanism involves ndvB, which we have previously shown to be expressed specifically in biofilms. In this study, we investigated the regulatory basis of this lifestyle-specific expression by developing an unstable GFP transcriptional reporter to observe the expression pattern of ndvB We found that, in addition to its expression in biofilms, ndvB was also upregulated in planktonic cells as they enter stationary phase...
January 19, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29351888/distribution-and-availability-of-mercury-and-methylmercury-in-different-waters-from-the-rio-madeira-basin-amazon
#2
Miguel Vieira, José V E Bernardi, José G Dórea, Bruno C P Rocha, Romulo Ribeiro, Luis F Zara
Waters from the Amazon Basin have distinct physicochemical characteristics that can be optically classified as "black", "clear" and "white". We studied the distribution of total-Hg (THg) and methyl-Hg (MeHg) in these waters and respective suspended solids, sediment, phytoplankton, zooplankton, and benthic macroinvertebrates (BM) in the Madeira River Basin. Compared with the other types of water, the more acidic "black" kind had the highest THg and MeHg concentrations. The trend (black > clear > white) occurred for the concentrations of THg and MeHg in sediments and in the biotic compartment (plankton, macroinvertebrates)...
January 16, 2018: Environmental Pollution
https://www.readbyqxmd.com/read/29351813/integrated-biogeography-of-planktonic-and-sedimentary-bacterial-communities-in-the-yangtze-river
#3
Tang Liu, An Ni Zhang, Jiawen Wang, Shufeng Liu, Xiaotao Jiang, Chenyuan Dang, Tao Ma, Sitong Liu, Qian Chen, Shuguang Xie, Tong Zhang, Jinren Ni
BACKGROUND: Bacterial communities are essential to the biogeochemical cycle in riverine ecosystems. However, little is presently known about the integrated biogeography of planktonic and sedimentary bacterial communities in large rivers. RESULTS: This study provides the first spatiotemporal pattern of bacterial communities in the Yangtze River, the largest river in Asia with a catchment area of 1,800,000 km2. We find that sedimentary bacteria made larger contributions than planktonic bacteria to the bacterial diversity of the Yangzte River ecosystem with the sediment subgroup providing 98...
January 19, 2018: Microbiome
https://www.readbyqxmd.com/read/29348589/novel-miniature-membrane-active-lipopeptidomimetics-against-planktonic-and-biofilm-embedded-methicillin-resistant-staphylococcus-aureus
#4
Seema Joshi, Sana Mumtaz, Jyotsna Singh, Santosh Pasha, Kasturi Mukhopadhyay
Escalating multidrug resistance and highly evolved virulence mechanisms have aggravated the clinical menace of methicillin-resistant Staphylococcus aureus (MRSA) infections. Towards development of economically viable staphylocidal agents here we report eight structurally novel tryptophan-arginine template based peptidomimetics. Out of the designed molecules, three lipopeptidomimetics (S-6, S-7 and S-8) containing 12-amino dodecanoic acid exhibited cell selectivity and good to potent activity against clinically relevant pathogens MRSA, methicillin-resistant Staphylococcus epidermidis and vancomycin-resistant Enterococcus faecium (MIC: 1...
January 18, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29348580/the-epibiotic-life-of-the-cosmopolitan-diatom-fragilariopsis-doliolus-on-heterotrophic-ciliates-in-the-open-ocean
#5
Flora J Vincent, Sébastien Colin, Sarah Romac, Eleonora Scalco, Lucie Bittner, Yonara Garcia, Rubens M Lopes, John R Dolan, Adriana Zingone, Colomban de Vargas, Chris Bowler
Diatoms are a diverse and ecologically important group of phytoplankton. Although most species are considered free living, several are known to interact with other organisms within the plankton. Detailed imaging and molecular characterization of any such partnership is, however, limited, and an appraisal of the large-scale distribution and ecology of such consortia was never attempted. Here, observation of Tara Oceans samples from the Benguela Current led to the detection of an epibiotic association between a pennate diatom and a tintinnid ciliate...
January 18, 2018: ISME Journal
https://www.readbyqxmd.com/read/29348571/high-resolution-time-series-reveals-cohesive-but-short-lived-communities-in-coastal-plankton
#6
Antonio M Martin-Platero, Brian Cleary, Kathryn Kauffman, Sarah P Preheim, Dennis J McGillicuddy, Eric J Alm, Martin F Polz
Because microbial plankton in the ocean comprise diverse bacteria, algae, and protists that are subject to environmental forcing on multiple spatial and temporal scales, a fundamental open question is to what extent these organisms form ecologically cohesive communities. Here we show that although all taxa undergo large, near daily fluctuations in abundance, microbial plankton are organized into clearly defined communities whose turnover is rapid and sharp. We analyze a time series of 93 consecutive days of coastal plankton using a technique that allows inference of communities as modular units of interacting taxa by determining positive and negative correlations at different temporal frequencies...
January 18, 2018: Nature Communications
https://www.readbyqxmd.com/read/29348527/the-human-muscarinic-acetylcholine-receptor-antagonist-dicyclomine-targets-signal-transduction-genes-and-inhibits-the-virulence-factors-in-the-human-pathogen-candida-albicans
#7
Awad Ali, Ashwini Jadhav, Priyanka Jangid, Rajendra Patil, Amruta Shelar, Sankunny Mohan Karuppayil
Dicyclomine is a human muscarinic acetylcholine receptor antagonist used for the treatment of abdominal cramps. We are reporting here that dicyclomine can inhibit the in vitro growth and virulence factors of the human pathogen Candida albicans very effectively. Dicyclomine inhibited adhesion, early biofilm, mature biofilm, and planktonic growth. Yeast to hyphal form transition of C. albicans in various inducer media such as serum, proline, glucose, and N-acetylglucosamine was inhibited. Dicyclomine also could kill C...
January 18, 2018: Journal of Antibiotics
https://www.readbyqxmd.com/read/29346584/in-vitro-interactions-between-iap-antagonist-at406-and-azoles-against-planktonic-cells-and-biofilms-of-pathogenic-fungi-candida-albicans-and-exophiala-dermatitidis
#8
Yi Sun, Lujuan Gao, Chengyan He, Ming Li, Tongxiang Zeng
In vitro interactions of AT406, a novel IAP antagonist, and azoles including itraconazole, voriconazole, and fluconazole against planktonic cells and biofilms of Candida albicans and Exophiala dermatitidis were assessed via broth microdilution checkerboard technique. AT406 alone exhibited limited antifungal activity. However, synergistic effect between AT406 and fluconazole was observed against both planktonic cells and biofilms of C. albicans, including one fluconazole-resistant strain. Moreover, synergism was also demonstrated between AT406 and itraconazole against both planktonic cells and biofilms of E...
January 13, 2018: Medical Mycology: Official Publication of the International Society for Human and Animal Mycology
https://www.readbyqxmd.com/read/29346561/floricolin-c-elicits-intracellular-ros-accumulation-and-disrupts-mitochondria-to-exert-fungicidal-action
#9
Ming Zhang, Wenqiang Chang, Hongzhuo Shi, Ying Li, Sha Zheng, Wei Li, Hongxiang Lou
Candida albicans, one most prevalent fungal pathogen, causes severe mucosal and invasive infections in predisposed individuals. The rise of fungal infection and drug-resistance demands the development of novel antifungal agents. In this study, we observed that floricolin C (FC), a p-terphenyl pigment from an endolichenic fungus, killed C. albicans cells at planktonic state or within biofilms through reactive oxygen species (ROS) accumulation. Further test revealed that FC could directly damage the mitochondria to cause ROS accumulation...
January 15, 2018: FEMS Yeast Research
https://www.readbyqxmd.com/read/29346530/bacterioplankton-composition-in-tropical-high-elevation-lakes-of-the-andean-plateau
#10
Pablo Aguilar, Cristina Dorador, Irma Vila, Ruben Sommaruga
High-elevation lakes in the tropics are subject to extreme environmental fluctuations and microbes may harbour a unique genomic repertoire, but their composition and diversity are largely unknown. Here we compared the planktonic bacterial community composition (BCC) and diversity of three tropical lakes located in the high Andean plateau (???4400 m above sea level) during the dry and wet season. Diversity in these lakes was higher in the cool and wet season than in the warm and dry one. OTUs composition was significantly different among lakes and between seasons...
January 16, 2018: FEMS Microbiology Ecology
https://www.readbyqxmd.com/read/29346398/dual-function-of-edta-with-silver-nanoparticles-for-root-canal-treatment-a-novel-modification
#11
Juan M Martinez-Andrade, Miguel Avalos-Borja, Alfredo R Vilchis-Nestor, Luis O Sanchez-Vargas, Ernestina Castro-Longoria
The chelating and antimicrobial capacity of a novel modification of 17% EDTA with silver nanoparticles (AgNPs) (EDTA-AgNPs) was evaluated in-vitro for root canal treatment (RCT). The EDTA-AgNPs solution was characterized by UV-Vis spectroscopy, ζ-potential and high-resolution transmission electron microscopy (HRTEM). Antimicrobial capacity was evaluated against Candida albicans and Staphylococcus aureus in planktonic and biofilm cells by broth macrodilution (24 h) and XTT assays, (1, 10 and 30 min) respectively...
2018: PloS One
https://www.readbyqxmd.com/read/29342840/evaluation-of-rapid-early-warning-approaches-to-track-shellfish-toxins-associated-with-dinophysis-and-alexandrium-blooms
#12
Theresa K Hattenrath-Lehmann, Mark W Lusty, Ryan B Wallace, Bennie Haynes, Zhihong Wang, Maggie Broadwater, Jonathan R Deeds, Steve L Morton, William Hastback, Leonora Porter, Karen Chytalo, Christopher J Gobler
Marine biotoxin-contaminated seafood has caused thousands of poisonings worldwide this century. Given these threats, there is an increasing need for improved technologies that can be easily integrated into coastal monitoring programs. This study evaluates approaches for monitoring toxins associated with recurrent toxin-producing Alexandrium and Dinophysis blooms on Long Island, NY, USA, which cause paralytic and diarrhetic shellfish poisoning (PSP and DSP), respectively. Within contrasting locations, the dynamics of pelagic Alexandrium and Dinophysis cell densities, toxins in plankton, and toxins in deployed blue mussels (Mytilus edulis) were compared with passive solid-phase adsorption toxin tracking (SPATT) samplers filled with two types of resin, HP20 and XAD-2...
January 13, 2018: Marine Drugs
https://www.readbyqxmd.com/read/29342119/novel-hybrid-formulations-based-on-thiourea-derivatives-and-core-shell-fe%C3%A2-o%C3%A2-c18-nanostructures-for-the-development-of-antifungal-strategies
#13
Carmen Limban, Alexandru Vasile Missir, Miron Teodor Caproiu, Alexandru Mihai Grumezescu, Mariana Carmen Chifiriuc, Coralia Bleotu, Luminita Marutescu, Marius Toma Papacocea, Diana Camelia Nuta
The continuously increasing global impact of fungal infections is requiring the rapid development of novel antifungal agents. Due to their multiple pharmacological activities, thiourea derivatives represent privileged candidates for shaping new drugs. We report here the preparation, physico-chemical characterization and bioevaluation of hybrid nanosystems based on new 2-((4-chlorophenoxy)methyl)-N-(substituted phenylcarbamo-thioyl)benzamides and Fe₃O₄@C18 core@shell nanoparticles. The new benzamides were prepared by an efficient method, then their structure was confirmed by spectral studies and elemental analysis and they were further loaded on Fe₃O₄@C18 nanostructures...
January 17, 2018: Nanomaterials
https://www.readbyqxmd.com/read/29340533/more-than-two-decades-after-the-introduction-of-limnoperna-fortunei-dunker-1857-in-la-plata-basin
#14
M A Pessotto, M G Nogueira
The golden mussel, Limnoperna fortunei, is an Asian freshwater bivalve introduced in South America in the beginning of the 1990's, probably through ballast water releases in La Plata River estuary. It dispersed north through Paraná, Uruguay and Paraguay Rivers. The study evaluated the macroscale (18° to 34° S; 45° to 60° W) distribution of L. fortunei (larval stages) in the main rivers and reservoirs of La Plata Basin. Samplings were performed through 68 µm vertical plankton net hauls. Limnological variables were simultaneously determined...
January 15, 2018: Brazilian Journal of Biology, Revista Brasleira de Biologia
https://www.readbyqxmd.com/read/29337262/longitudinal-patterns-and-response-lengths-of-algae-in-riverine-ecosystems-a-model-analysis-emphasising-benthic-pelagic-interactions
#15
Christoph G Jäger, Dietrich Borchardt
In riverine ecosystems primary production is principally possible in two habitats: in the benthic layer by sessile algae and in the surface water by planktonic algae being transported downstream. The relevance of these two habitats generally changes along the rivers' continuum. However, analyses of the interaction of algae in these two habitats and their controlling factors in riverine ecosystems are, so far, very rare. We use a simplified advection-diffusion model system combined with ecological process kinetics to analyse the interaction of benthic and planktonic algae and nutrients along idealised streams and rivers at regional to large scales...
January 11, 2018: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/29336882/histobacteriologic-conditions-of-the-apical-root-canal-system-and-periapical-tissues-in-teeth-associated-with-sinus-tracts
#16
Domenico Ricucci, Simona Loghin, Lucio S Gonçalves, Isabela N Rôças, José F Siqueira
INTRODUCTION: This histobacteriologic study described the pattern of intraradicular and extraradicular infections in teeth with sinus tracts and chronic apical abscesses. METHODS: The material comprised biopsy specimens from 24 (8 untreated and 16 treated) roots of teeth associated with apical periodontitis and a sinus tract. Specimens were obtained by periradicular surgery or extraction and were processed for histobacteriologic and histopathologic methods. RESULTS: Bacteria were found in the apical root canal system of all specimens, in the main root canal (22 teeth) and within ramifications (17 teeth)...
January 12, 2018: Journal of Endodontics
https://www.readbyqxmd.com/read/29336517/environmental-sequencing-fills-the-gap-between-parasitic-haplosporidians-and-free-living-giant-amoebae
#17
Georgia M Ward, Sigrid Neuhauser, René Groben, Stefan Ciaghi, Cédric Berney, Sarah Romac, David Bass
Class Ascetosporea (Rhizaria; Endomyxa) comprises many parasites of invertebrates. Within this group, recent group-specific environmental DNA (eDNA) studies have contributed to the establishment of the new order Mikrocytida, a new phylogeny and characterisation of Paramyxida, and illuminated the diversity and distribution of haplosporidians. Here we use general and lineage-specific PCR primers to investigate the phylogenetic 'gap' between haplosporidians and their closest known free-living relatives, the testate amoeba Gromia and reticulate amoeba Filoreta...
January 16, 2018: Journal of Eukaryotic Microbiology
https://www.readbyqxmd.com/read/29336102/behavioural-responses-of-the-yellow-emitting-annelid-tomopteris-helgolandica-to-photic-stimuli
#18
Anaïd Gouveneaux, Marie-Charlotte Gielen, Jérôme Mallefet
In contrast to most mesopelagic bioluminescent organisms specialised in the emission and reception of blue light, the planktonic annelid Tomopteris helgolandica produces yellow light. This unusual feature has long been suggested to serve for intraspecific communication. Yet, this virtually admitted hypothesis has never been tested. In this behavioural study of spectral colour sensitivity, we first present an illustrated repertoire of the postures and action patterns described by captive specimens. Then video tracking and motion analysis are used to quantify the behavioural responses of singled out worms to photic stimuli imitating intraspecific (yellow) or interspecific (blue) bioluminescent signals...
January 16, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29335484/microbial-competition-of-rhodotorula-mucilaginosa-uanl-001l-and-e-coli-increase-biosynthesis-of-non-toxic-exopolysaccharide-with-applications-as-a-wide-spectrum-antimicrobial
#19
Augusto Vazquez-Rodriguez, Ximena G Vasto-Anzaldo, Daniel Barboza Perez, Eduardo Vázquez-Garza, Héctor Chapoy-Villanueva, Gerardo García-Rivas, Javier A Garza-Cervantes, Jéssica J Gómez-Lugo, Alma Elizabeth Gomez-Loredo, Maria Teresa Garza Gonzalez, Xristo Zarate, Jose Ruben Morones-Ramirez
Bacterial species are able to colonize and establish communities in biotic and abiotic surfaces. Moreover, within the past five decades, incidence of bacterial strains resistant to currently used antibiotics has increased dramatically. This has led to diverse health issues and economical losses for different industries. Therefore, there is a latent need to develop new and more efficient antimicrobials. This work reports an increased production of an exopolysaccharide in a native yeast strain isolated from the Mexican Northeast, Rhodotorula mucilaginosa UANL-001L, when co-cultured with E...
January 15, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29334249/antimicrobial-activity-of-1-3-4-oxadiazole-derivatives-against-planktonic-cells-and-biofilm-of-staphylococcus-aureus
#20
Zhaojun Zheng, Qingzhong Liu, Wooseong Kim, Nagendran Tharmalingam, Beth Burgwyn Fuchs, Eleftherios Mylonakis
AIM:  Staphylococcus aureus is a major cause of severe hospital-acquired infections, and biofilm formation is an important part of staphylococcal pathogenesis. Therefore, developing new antimicrobial agents against both planktonic cells and biofilm of S. aureus is a major challenge. RESULTS: Three 1,3,4-oxadiazole derivatives exhibited antimicrobial activity against seven S. aureus strains in vitro, with minimum inhibitory concentrations ranging from 4 to 32 μg/ml...
January 15, 2018: Future Medicinal Chemistry
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