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Stephanie Loeb, Chuanhao Li, Jae-Hong Kim
A simple heat treatment, perhaps the most globally recognized point-of-use water sterilization method, is seemingly effective against all major pathogens of concern, but bulk water boiling is not energy efficient or sustainable. Herein, we present the first application of solar-to-thermal converting nanomaterials for the direct inactivation of bacteria and viruses in drinking water through the application of Au nanorods, carbon black, and Au nanorod-carbon black composite materials as light absorbers. With broad absorption bands spanning the visible and near-infrared wavelengths, at sufficient concentrations, these nanoparticles induce multiple scattering events, increasing photon absorption probability and concentrating the light within a small spatial domain, leading to localized, intense heating that inactivates microorganisms in close proximity...
December 14, 2017: Environmental Science & Technology
Guimin Zhang, Yin Zhao, Sathish Paramasivan, Katharina Richter, Sandra Morales, Peter-John Wormald, Sarah Vreugde
BACKGROUND: Bacteriophage (phage) therapy has been proposed as an alternative to antibiotics. Phages have been shown to kill antibiotic resistant Staphylococcus aureus strains; however, it is unknown whether stress-induced antibiotic tolerance affects S. aureus susceptibility to phages. Our objective was to determine the effectiveness of 2 phages currently in clinical development, against antibiotic-resistant and induced antibiotic-tolerant clinical S. aureus isolates. METHODS: Antibiotic tolerant S...
December 14, 2017: International Forum of Allergy & Rhinology
Ik-Hyun Kim, Jae-Yeong Han, In-Sook Cho, HyeKyoung Ju, Jae Sun Moon, Eun-Young Seo, Hong Gi Kim, John Hammond, Hyoun-Sub Lim
The full-length sequence of a new isolate of Apple chlorotic leaf spot virus (ACLSV) from Korea was divergent, but most closely related to the Japanese isolate A4, at 84% nucleotide identity. The full-length cDNA of the Korean isolate of ACLSV was cloned into a binary vector downstream of the bacteriophage T7 RNA promoter and the Cauliflower mosaic virus 35S promoter. Chenopodium quinoa was successfully infected using in vitro transcripts synthesized using the T7 promoter, detected at 20 days post inoculation (dpi), but did not produce obvious symptoms...
December 2017: Plant Pathology Journal
Maroš Pleška, Călin C Guet
Restriction-modification systems are widespread genetic elements that protect bacteria from bacteriophage infections by recognizing and cleaving heterologous DNA at short, well-defined sequences called restriction sites. Bioinformatic evidence shows that restriction sites are significantly underrepresented in bacteriophage genomes, presumably because bacteriophages with fewer restriction sites are more likely to escape cleavage by restriction-modification systems. However, how mutations in restriction sites affect the likelihood of bacteriophage escape is unknown...
December 2017: Biology Letters
Pavel Mikel, Petra Vasickova, Petr Kralik
MS2 phage-like particles (MS2 PLP) are artificially constructed pseudo-viral particles derived from bacteriophage MS2. They are able to carry a specific single stranded RNA (ssRNA) sequence of choice inside their capsid, thus protecting it against the effects of ubiquitous nucleases. Such particles are able to mimic ssRNA viruses and, thus, may serve as the process control for molecular detection and quantification of such agents in several kinds of matrices, vaccines and vaccine candidates, drug delivery systems, and systems for the display of immunologically active peptides or nanomachines...
December 13, 2017: Scientific Reports
Alexander Harms, Cinzia Fino, Michael A Sørensen, Szabolcs Semsey, Kenn Gerdes
Bacterial persisters are phenotypic variants that survive antibiotic treatment in a dormant state and can be formed by multiple pathways. We recently proposed that the second messenger (p)ppGpp drives Escherichia coli persister formation through protease Lon and activation of toxin-antitoxin (TA) modules. This model found considerable support among researchers studying persisters but also generated controversy as part of recent debates in the field. In this study, we therefore used our previous work as a model to critically examine common experimental procedures to understand and overcome the inconsistencies often observed between results of different laboratories...
December 12, 2017: MBio
April Pawluk, Megha Shah, Marios Mejdani, Charles Calmettes, Trevor F Moraes, Alan R Davidson, Karen L Maxwell
CRISPR (clustered regularly interspaced short palindromic repeat)-Cas adaptive immune systems are prevalent defense mechanisms in bacteria and archaea. They provide sequence-specific detection and neutralization of foreign nucleic acids such as bacteriophages and plasmids. One mechanism by which phages and other mobile genetic elements are able to overcome the CRISPR-Cas system is through the expression of anti-CRISPR proteins. Over 20 different families of anti-CRISPR proteins have been described, each of which inhibits a particular type of CRISPR-Cas system...
December 12, 2017: MBio
Joan A Geoghegan, Alan D Irvine, Timothy J Foster
Staphylococcus aureus is frequently isolated from the skin of atopic dermatitis (AD) patients during flares. The normal microbiota is disrupted and the diversity of the microorganisms on the skin is reduced. Many species that produce inhibitors of S. aureus growth decline. Strains from S. aureus clonal complex 1 are enriched among AD sufferers whereas the CC30 strains most frequently isolated from nasal carriers in the normal population are much rarer in AD. S. aureus expresses several molecules that contribute to the intensity of symptoms, including δ-toxin which stimulates mast cells, α-toxin which damages keratinocytes, phenol-soluble modulins which stimulate cytokine release by keratinocytes, protein A which triggers inflammatory responses from keratinocytes, superantigens which trigger B cell expansion and cytokine release, and proinflammatory lipoproteins...
December 9, 2017: Trends in Microbiology
Shaoying Wang, Zhengyi Zhao, Farzin Haque, Peixuan Guo
Biological systems contain highly-ordered structures performing diverse functions. The elegant structures of biomachines have inspired the development of nanopores as single molecule sensors. Over the years, the utility of nanopores for detecting a wide variety of analytes have rapidly emerged for sensing, sequencing and diagnostic applications. Several protein channels with diverse shapes and sizes, such as motor channels from bacteriophage Phi29, SPP1, T3, and T4, as well as α-hemolysin, MspA, aerolysin, FluA, OmpF/G, CsgG, ClyA, have been continually investigated and developed as nanopores...
December 9, 2017: Current Opinion in Biotechnology
Yingyuan Sun, Aaron P Roznowski, Joshua M Tokuda, Thomas Klose, Alexander Mauney, Lois Pollack, Bentley A Fane, Michael G Rossmann
Unlike tailed bacteriophages, which use a preformed tail for transporting their genomes into a host bacterium, the ssDNA bacteriophage ΦX174 is tailless. Using cryo-electron microscopy and time-resolved small-angle X-ray scattering, we show that lipopolysaccharides (LPS) form bilayers that interact with ΦX174 at an icosahedral fivefold vertex and induce single-stranded (ss) DNA genome ejection. The structures of ΦX174 complexed with LPS have been determined for the pre- and post-ssDNA ejection states. The ejection is initiated by the loss of the G protein spike that encounters the LPS, followed by conformational changes of two polypeptide loops on the major capsid F proteins...
December 11, 2017: Proceedings of the National Academy of Sciences of the United States of America
Paul C M Fogg, Ellen Younger, Booshini D Fernando, Thanafez Khaleel, W Marshall Stark, Margaret C M Smith
To establish a prophage state, the genomic DNA of temperate bacteriophages normally becomes integrated into the genome of their host bacterium by integrase-mediated, site-specific DNA recombination. Serine integrases catalyse a single crossover between an attachment site in the host (attB) and a phage attachment site (attP) on the circularized phage genome to generate the integrated prophage DNA flanked by recombinant attachment sites, attL and attR. Exiting the prophage state and entry into the lytic growth cycle requires an additional phage-encoded protein, the recombination directionality factor or RDF, to mediate recombination between attL and attR and excision of the phage genome...
December 8, 2017: Nucleic Acids Research
Iain A Murray, Richard D Morgan, Yvette Luyten, Alexey Fomenkov, Ivan R Corrêa, Nan Dai, Mohammed B Allaw, Xing Zhang, Xiaodong Cheng, Richard J Roberts
We describe the cloning, expression and characterization of the first truly non-specific adenine DNA methyltransferase, M.EcoGII. It is encoded in the genome of the pathogenic strain Escherichia coli O104:H4 C227-11, where it appears to reside on a cryptic prophage, but is not expressed. However, when the gene encoding M.EcoGII is expressed in vivo - using a high copy pRRS plasmid vector and a methylation-deficient E. coli host-extensive in vivo adenine methylation activity is revealed. M.EcoGII methylates adenine residues in any DNA sequence context and this activity extends to dA and rA bases in either strand of a DNA:RNA-hybrid oligonucleotide duplex and to rA bases in RNAs prepared by in vitro transcription...
December 8, 2017: Nucleic Acids Research
Sergey Potapov, Olga Olga, Andrey Krasnopeev, Anna Gladkikh, Marsel Kabilov, Aleksey Tupikin, Tatyana V Butina
Based on second generation sequencing (MiSeq platform), we determined the genetic diversity of T4-like bacteriophages of the family Myoviridae by analysing fragments of the major capsid protein gene g23 in the plankton of Lake Baikal. The sampling depth in our study was significantly higher than in those obtained by the Sanger method before. We obtained 33701 sequences of the g23 gene fragments, 141 OTUs of which were identified. 86 OTUs (60.9%) had the closest relatives from lakes Bourget and Annecy, and 28 OTUs (19...
December 5, 2017: FEMS Microbiology Letters
Shoichi Mitsunaka, Naoki Sudo, Yasuhiko Sekine
Bacteriophages are genetic elements that play key roles in the evolution and diversification of bacterial genomes. The Shiga toxin (Stx)-encoding phage plays an important role in the horizontal transfer of the stx gene. However, the influence of the Stx phage integration on the physiological properties and gene expression pattern of the host have not been clearly resolved. In this study, we constructed the Sp5 lysogen through lysogenisation of E. coli K-12 by Sp5, an Stx2 phage in enterohaemorrhagic E. coli (EHEC) O157:H7 Sakai, and examined the effect of the resulting lysogen on cell motility under various growth conditions...
December 8, 2017: Journal of General and Applied Microbiology
Maria João Jacinto, David J S Patinha, Isabel M Marrucho, João Gonçalves, Richard C Willson, Ana M Azevedo, M Raquel Aires-Barros
M13 is a filamentous, non-lytic bacteriophage that infects Escherichia coli via the F pilus. Currently, phage M13 is widely used in phage display technology and bio-nanotechnology, and is considered a possible antibacterial therapeutic agent, among other applications. Conventional phage purification involves 5-7 operational steps, with high operational costs and significant product loss (approximately 60%). In this work, we propose a scalable purification process for M13 bacteriophage using a novel stationary phase based on a polymeric ionic liquid (PIL) with a positively charged backbone structure...
December 6, 2017: Journal of Chromatography. A
Badreddine Douzi, Laureen Logger, Silvia Spinelli, Stéphanie Blangy, Christian Cambillau, Eric Cascales
The Type VI secretion system (T6SS) is a specialized macromolecular complex dedicated to the delivery of protein effectors into both eukaryotic and bacterial cells. The general mechanism of action of the T6SS is similar to the injection of DNA by contractile bacteriophages. The cytoplasmic portion of the T6SS is evolutionarily, structurally and functionally related to the phage tail complex. It is composed of an inner tube made of stacked Hcp hexameric rings, engulfed within a sheath and built on a baseplate...
December 6, 2017: Journal of Molecular Biology
Florian Praetorius, Benjamin Kick, Karl L Behler, Maximilian N Honemann, Dirk Weuster-Botz, Hendrik Dietz
DNA nanotechnology, in particular DNA origami, enables the bottom-up self-assembly of micrometre-scale, three-dimensional structures with nanometre-precise features. These structures are customizable in that they can be site-specifically functionalized or constructed to exhibit machine-like or logic-gating behaviour. Their use has been limited to applications that require only small amounts of material (of the order of micrograms), owing to the limitations of current production methods. But many proposed applications, for example as therapeutic agents or in complex materials, could be realized if more material could be used...
December 6, 2017: Nature
J Alfred Bonilla, Sharon Isern, Ann M Findley, Karen K Klyczek, Scott F Michael, Margaret S Saha, William J Buchser, Mark H Forsyth, Sudip Paudel, Christopher R Gissendanner, Allison M D Wiedemeier, Fernanda L Alonzo, Rebecca A Garlena, Daniel A Russell, Welkin H Pope, Steven G Cresawn, Deborah Jacobs-Sera, Graham F Hatfull
We report the complete genome sequences of 19 cluster CA bacteriophages isolated from environmental samples using Rhodococcus erythropolis as a host. All of the phages are Siphoviridae, have similar genome lengths (46,314 to 46,985 bp) and G+C contents (58.5 to 58.8%), and share nucleotide sequence similarity.
December 7, 2017: Genome Announcements
Veronna Marie, Johnson Lin
Due to the continued persistence of waterborne viral-associated infections, the presence of enteric viruses is a concern. Notwithstanding the health implications, viral diversity and abundance is an indicator of water quality declination in the environment. The aim of this study was to evaluate the presence of viruses (bacteriophage and enteric viruses) in a highly polluted, anthropogenic-influenced river system over a 6-month period at five sampling points. Cytopathic-based tissue culture assays revealed that the isolated viruses were infectious when tested on Hep-G2, HEK293 and Vero cells...
October 2017: Journal of Water and Health
Rolf Lood, Gizem Ertürk, Bo Mattiasson
The spread of antibiotic resistance is currently a major threat to health that humanity is facing today. Novel multidrug and pandrug resistant bacteria are reported on a yearly basis, while the development of novel antibiotics is lacking. Focus to limit the spread of antibiotic resistance by reducing the usage of antibiotics in health care, veterinary applications, and meat production, have been implemented, limiting the exposure of pathogens to antibiotics, thus lowering the selection of resistant strains...
2017: Frontiers in Microbiology
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