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https://www.readbyqxmd.com/read/28110506/antibiotic-discovery-throughout-the-small-world-initiative-a-molecular-strategy-to-identify-biosynthetic-gene-clusters-involved-in-antagonistic-activity
#1
Elizabeth Davis, Tyler Sloan, Krista Aurelius, Angela Barbour, Elijah Bodey, Brigette Clark, Celeste Dennis, Rachel Drown, Megan Fleming, Allison Humbert, Elizabeth Glasgo, Trent Kerns, Kelly Lingro, MacKenzie McMillin, Aaron Meyer, Breanna Pope, April Stalevicz, Brittney Steffen, Austin Steindl, Carolyn Williams, Carmen Wimberley, Robert Zenas, Kristen Butela, Hans Wildschutte
The emergence of bacterial pathogens resistant to all known antibiotics is a global health crisis. Adding to this problem is that major pharmaceutical companies have shifted away from antibiotic discovery due to low profitability. As a result, the pipeline of new antibiotics is essentially dry and many bacteria now resist the effects of most commonly used drugs. To address this global health concern, citizen science through the Small World Initiative (SWI) was formed in 2012. As part of SWI, students isolate bacteria from their local environments, characterize the strains, and assay for antibiotic production...
January 22, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28110115/application-of-an-ecosystem-model-to-evaluate-the-importance-of-different-processes-and-food-web-structure-for-transfer-of-13-elements-in-a-shallow-lake
#2
L Konovalenko, C Bradshaw, E Andersson, U Kautsky
In environmental risk assessments of nuclear waste, there is need to estimate the potential risks of a large number of radionuclides over a long time period during which the environment is likely to change. Usually concentration ratios (CRs) are used to calculate the activity concentrations in organisms. However, CRs are not available for all radionuclides and they are not easily scalable to the varying environment. Here, an ecosystem transport model of elements, which estimates concentrations in organisms using carbon flows and food transfer instead of CR is presented...
January 18, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/28109686/from-bacteria-to-whales-using-functional-size-spectra-to-model-marine-ecosystems
#3
REVIEW
Julia L Blanchard, Ryan F Heneghan, Jason D Everett, Rowan Trebilco, Anthony J Richardson
Size-based ecosystem modeling is emerging as a powerful way to assess ecosystem-level impacts of human- and environment-driven changes from individual-level processes. These models have evolved as mechanistic explanations for observed regular patterns of abundance across the marine size spectrum hypothesized to hold from bacteria to whales. Fifty years since the first size spectrum measurements, we ask how far have we come? Although recent modeling studies capture an impressive range of sizes, complexity, and real-world applications, ecosystem coverage is still only partial...
January 18, 2017: Trends in Ecology & Evolution
https://www.readbyqxmd.com/read/28109187/antimicrobial-and-antioxidant-activities-of-saccharomyces-cerevisiae-ifst062013-a-potential-probiotic
#4
Md Fakruddin, Md Nur Hossain, Monzur Morshed Ahmed
BACKGROUND: Probiotic yeast has become a field of interest to scientists in recent years. METHODS: Conventional cultural method was employed to isolate and identify yeast and standard methods were used to determine different probiotic attributes, antimicrobial and antioxidant properties. RESULTS: This study reports potential probiotic properties of a strain of S. cerevisiae IFST 062013 isolated from fruit. The isolate is tolerant to a wide range of temperature and pH, high concentration of bile salt and NaCl, gastric juice, intestinal environment, α-amylase, trypsin and lysozyme...
January 21, 2017: BMC Complementary and Alternative Medicine
https://www.readbyqxmd.com/read/28109041/endemic-cyanophages-and-the-puzzle-of-phage-bacteria-coevolution
#5
Otto X Cordero
A recent genomic analysis of Synechococcus cyanophages sampled for over 15 years reveals a remarkable pattern of stable phage population structure, highly reminiscent of the ecotype structure observed in bacteria and archaeal ecotypes. In this highlight I discuss the importance of this finding and the questions and opportunities it opens to learn more about the nature of phage-bacterial coevolution in the environment. This article is protected by copyright. All rights reserved.
January 20, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28108758/composition-of-gut-microbiota-in-the-gibel-carp-carassius-auratus-gibelio-varies-with-host-development
#6
Xinghao Li, Li Zhou, Yuhe Yu, Jiajia Ni, Wenjie Xu, Qingyun Yan
To understand how a bacteria-free fish gut ecosystem develops microbiota as the fish ages, we performed a 1-year study on the gut microbiota of hatchling gibel carp (Carassius auratus gibelio). Our results indicate that the gut microbial diversity increases significantly as the fish develop. The gut microbial community composition showed significant shifts corresponding to host age and appeared to shift at two time points despite consistent diet and environmental conditions, suggesting that some features of the gut microbial community may be determined by the host's development...
January 20, 2017: Microbial Ecology
https://www.readbyqxmd.com/read/28108360/archaeal-lipids-in-oral-delivery-of-therapeutic-peptides
#7
Ann-Christin Jacobsen, Sara M Jensen, Gert Fricker, Martin Brandl, Alexander Treusch
Archaea contain membrane lipids that differ from those found in the other domains of life (Eukarya and Bacteria). These lipids consist of isoprenoid chains attached via ether bonds to the glycerol carbons at the sn-2,3 positions. Two types of ether lipids are known, polar diether lipids and bipolar tetraether lipids. The inherent chemical stability and unique membrane-spanning characteristics of tetraether lipids render them interesting for oral drug delivery purposes. Archaeal lipids form liposomes spontaneously (archaeosomes) and may be incorporated in conventional liposomes (mixed vesicles)...
January 17, 2017: European Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28106879/bacterial-community-segmentation-facilitates-the-prediction-of-ecosystem-function-along-the-coast-of-the-western-antarctic-peninsula
#8
Jeff S Bowman, Linda A Amaral-Zettler, Jeremy J Rich, Catherine M Luria, Hugh W Ducklow
Bacterial community structure can be combined with observations of ecophysiological data to build predictive models of microbial ecosystem function. These models are useful for understanding how function might change in response to a changing environment. Here we use five spring-summer seasons of bacterial community structure and flow cytometry data from a productive coastal site along the western Antarctic Peninsula to construct models of bacterial production (BP), an ecosystem function that heterotrophic bacteria provide...
January 20, 2017: ISME Journal
https://www.readbyqxmd.com/read/28106859/burkholderia-cepacia-complex-regulation-of-virulence-gene-expression-a-review
#9
REVIEW
Sílvia A Sousa, Joana R Feliciano, Tiago Pita, Soraia I Guerreiro, Jorge H Leitão
Burkholderia cepacia complex (Bcc) bacteria emerged as opportunistic pathogens in cystic fibrosis and immunocompromised patients. Their eradication is very difficult due to the high level of intrinsic resistance to clinically relevant antibiotics. Bcc bacteria have large and complex genomes, composed of two to four replicons, with variable numbers of insertion sequences. The complexity of Bcc genomes confers a high genomic plasticity to these bacteria, allowing their adaptation and survival to diverse habitats, including the human host...
January 19, 2017: Genes
https://www.readbyqxmd.com/read/28106797/the-complex-relationship-between-virulence-and-antibiotic-resistance
#10
REVIEW
Meredith Schroeder, Benjamin D Brooks, Amanda E Brooks
Antibiotic resistance, prompted by the overuse of antimicrobial agents, may arise from a variety of mechanisms, particularly horizontal gene transfer of virulence and antibiotic resistance genes, which is often facilitated by biofilm formation. The importance of phenotypic changes seen in a biofilm, which lead to genotypic alterations, cannot be overstated. Irrespective of if the biofilm is single microbe or polymicrobial, bacteria, protected within a biofilm from the external environment, communicate through signal transduction pathways (e...
January 18, 2017: Genes
https://www.readbyqxmd.com/read/28106321/conserved-two-component-hik34-rre1-module-directly-activates-heat-stress-inducible-transcription-of-major-chaperone-and-other-genes-in-synechococcus-elongatus-pcc-7942
#11
Ikki Kobayashi, Satoru Watanabe, Yu Kanesaki, Tomohiro Shimada, Hirofumi Yoshikawa, Kan Tanaka
Bacteria and other organisms, including cyanobacteria, employ two-component signal transducing modules comprising histidine kinases and response regulators to acclimate to changing environments. While the number and composition of these modules differ among cyanobacteria, two response regulators that contain DNA binding domains, RpaB and Rre1, are conserved in all sequenced cyanobacterial genomes and are essential for viability. Although RpaB negatively or positively regulates high light and other stress-responsive gene expression, little is known about the function of Rre1...
January 20, 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28106311/potential-applications-of-non-thermal-plasmas-against-biofilm-associated-microorganisms-in-vitro
#12
REVIEW
Pradeep Puligundla, Chulkyoon Mok
Biofilms as complex microbial communities attached to surfaces are posing several challenges in different sectors, ranging from food and healthcare to desalination and power generation. Biofilms survive in hostile environments due to a distinct physiology and behavior in comparison to their planktonic counterparts. They are ubiquitous, resilient, and difficult to eradicate due to their resistant phenotype. Several chemical-based cleaning and disinfection regimens are conventionally used against biofilm-dwelling microorganisms in vitro...
January 20, 2017: Journal of Applied Microbiology
https://www.readbyqxmd.com/read/28105601/gordonia-isolation-and-identification-in-clinical-samples-and-role-in-biotechnology
#13
REVIEW
Fatemeh Andalibi, Mehdi Fatahi-Bafghi
Gordonia spp. are members of the actinomycete family, and the environment, especially soil, is the natural habitat of this genus of bacteria. Gordonia spp. are important for two aspects: first, some Gordonia species cause a broad spectrum of diseases in healthy and immunocompromised individuals; second, these bacteria are capable of producing useful secondary metabolites, which may be used in various industries; therefore, discrimination of the genus Gordonia from other genera in the actinomycete family is important...
January 20, 2017: Folia Microbiologica
https://www.readbyqxmd.com/read/28104802/the-ssl2245-sll1130-toxin-antitoxin-system-mediates-heat-induced-programmed-cell-death-in-synechocystis-sp-pcc6803
#14
Afshan Srikumar, Pilla Sankara Krishna, Dokku Sivaramakrishna, Stefan Kopfmann, Wolfgang R Hess, Musti J Swamy, Sue Lin-Chao, Jogadhenu S S Prakash
Two putative heat responsive genes, ssl2245 and sll1130 constitute an operon that also has characteristics of a toxin-antitoxin system, thus joining several enigmatic features. Closely related orthologs of Ssl2245 and Sll1130 exist in widely different bacteria, which thrive under environments with large fluctuations in temperature and salinity, among which some are thermo-epilithic biofilm forming cyanobacteria. Transcriptome analyses revealed that the CRISPR genes as well as several hypothetical genes were commonly up-regulated in Δssl2245 and Δsll1130 mutants...
January 19, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28104400/the-difference-in-in-vivo-sensitivity-between-bacillus-licheniformis-perr-and-bacillus-subtilis-perr-is-due-to-the-different-cellular-environments
#15
Jung-Hoon Kim, Young-Bin Won, Chang-Jun Ji, Yoon-Mo Yang, Su-Hyun Ryu, Shin-Yeong Ju, Yumi Kwon, Yeh-Eun Lee, Jin-Won Lee
PerR, a member of Fur family of metal-dependent regulators, is a major peroxide sensor in many Gram positive bacteria, and controls the expression of genes involved in peroxide resistance. Bacillus licheniformis, a close relative to the well-studied model organism Bacillus subtilis, contains three PerR-like proteins (PerRBL, PerR2 and PerR3) in addition to Fur and Zur. In the present study, we characterized the role of PerRBL in B. licheniformis. In vitro and in vivo studies indicate that PerRBL, like PerRBS, uses either Fe(2+) or Mn(2+) as a corepressor and only the Fe(2+)-bound form of PerRBL senses low levels of H2O2 by iron-mediated histidine oxidation...
January 16, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28104340/why-new-antibiotics-are-not-obviously-useful-now
#16
Grégory Dubourg, Cédric Abat, Didier Raoult
For several years, the threat of antibiotic resistance and its health cost has dramatically risen and various alarming figures have been proposed to illustrate the mortality due to antibiotic resistance. However, predictions concerning different living beings are doomed to failure, as theorised in Alice's 'living croquet' theory. Actors of antibiotic resistance are the doctors, the patient and the bacteria. Considering that animals and the environment are involved, future disasters are unpredictable. Here we evaluate in a rational manner the reliability of scientific sources showing increasing resistance to antibiotics or increasing mortality related to antibiotic resistance, and we finally consider antibiotic resources to face the situation...
January 16, 2017: International Journal of Antimicrobial Agents
https://www.readbyqxmd.com/read/28103254/a-highly-active-endo-levanase-bt1760-of-a-dominant-mammalian-gut-commensal-bacteroides-thetaiotaomicron-cleaves-not-only-various-bacterial-levans-but-also-levan-of-timothy-grass
#17
Karin Mardo, Triinu Visnapuu, Heiki Vija, Anneli Aasamets, Katrin Viigand, Tiina Alamäe
Bacteroides thetaiotaomicron, an abundant commensal of the human gut, degrades numerous complex carbohydrates. Recently, it was reported to grow on a β-2,6-linked polyfructan levan produced by Zymomonas mobilis degrading the polymer into fructooligosaccharides (FOS) with a cell surface bound endo-levanase BT1760. The FOS are consumed by B. thetaiotaomicron, but also by other gut bacteria, including health-promoting bifidobacteria and lactobacilli. Here we characterize biochemical properties of BT1760, including the activity of BT1760 on six bacterial levans synthesized by the levansucrase Lsc3 of Pseudomonas syringae pv...
2017: PloS One
https://www.readbyqxmd.com/read/28102347/low-level-predation-by-lytic-phage-phiipla-rodi-promotes-biofilm-formation-and-triggers-the-stringent-response-in-staphylococcus-aureus
#18
Lucía Fernández, Silvia González, Ana Belén Campelo, Beatriz Martínez, Ana Rodríguez, Pilar García
An important lesson from the war on pathogenic bacteria has been the need to understand the physiological responses and evolution of natural microbial communities. Bacterial populations in the environment are generally forming biofilms subject to some level of phage predation. These multicellular communities are notoriously resistant to antimicrobials and, consequently, very difficult to eradicate. This has sparked the search for new therapeutic alternatives, including phage therapy. This study demonstrates that S...
January 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28102305/structure-and-membrane-interactions-of-the-homodimeric-antibiotic-peptide-homotarsinin
#19
Rodrigo M Verly, Jarbas M Resende, Eduardo F C Junior, Mariana T Q de Magalhães, Carlos F C R Guimarães, Victor H O Munhoz, Marcelo Porto Bemquerer, Fábio C L Almeida, Marcelo M Santoro, Dorila Piló-Veloso, Burkhard Bechinger
Antimicrobial peptides (AMPs) from amphibian skin are valuable template structures to find new treatments against bacterial infections. This work describes for the first time the structure and membrane interactions of a homodimeric AMP. Homotarsinin, which was found in Phyllomedusa tarsius anurans, consists of two identical cystine-linked polypeptide chains each of 24 amino acid residues. The high-resolution structures of the monomeric and dimeric peptides were determined in aqueous buffers. The dimer exhibits a tightly packed coiled coil three-dimensional structure, keeping the hydrophobic residues screened from the aqueous environment...
January 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28102290/wells-provide-a-distorted-view-of-life-in-the-aquifer-implications-for-sampling-monitoring-and-assessment-of-groundwater-ecosystems
#20
Kathryn Korbel, Anthony Chariton, Sarah Stephenson, Paul Greenfield, Grant C Hose
When compared to surface ecosystems, groundwater sampling has unique constraints, including limited access to ecosystems through wells. In order to monitor groundwater, a detailed understanding of groundwater biota and what biological sampling of wells truly reflects, is paramount. This study aims to address this uncertainty, comparing the composition of biota in groundwater wells prior to and after purging, with samples collected prior to purging reflecting a potentially artificial environment and samples collected after purging representing the surrounding aquifer...
January 19, 2017: Scientific Reports
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