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https://www.readbyqxmd.com/read/29148917/evaluation-of-antibacterial-activity-and-toxic-metal-removal-of-chemically-synthesized-magnetic-iron-oxide-titanium-coated-nanoparticles-and-application-in-bacterial-treatment
#1
Yasser A M Abdulhady, Mona M El-Shazly, Reham F El-Kased
Co-precipitation method was used for preparation of two types of iron oxide nanoparticles coated by titanium dioxide according to divalent salts used. The average size of iron oxide nanoparticles coated by titanium dioxide measured by particle size analyzer, ranged approximately between 20 nm and 100 nm with mean particle size of 60 nm. Characterization of the prepared nanoparticles was done by X-ray diffraction analysis and scanning electron microscope indicating the sole existence of inverse cubic spinel phase of magnetic iron oxide nanoparticles...
November 17, 2017: Journal of Environmental Science and Health. Part A, Toxic/hazardous Substances & Environmental Engineering
https://www.readbyqxmd.com/read/29146596/structure-and-function-of-the-leptospira-interrogans-peroxide-stress-regulator-perr-an-atypical-perr-devoid-of-a-structural-metal-binding-site
#2
Mounira Kebouchi, Frederick Saul, Raleb Taher, Annie Landier, Benedicte Beaudeau, Sarah Dubrac, Patrick Weber, Ahmed Haouz, Mathieu Picardeau, Nadia Benaroudj
Peroxide sensing is essential for bacteria survival during aerobic metabolism and host infection. Peroxide stress regulators (PerRs) are homodimeric transcriptional repressors with each monomer typically containing both structural and regulatory metal-binding sites. PerR binding to gene promoters is controlled by the presence of iron in the regulatory site, and iron-catalyzed oxidation of PerR by H2O2 leads to the dissociation of PerR from DNA. In addition to a regulatory metal, most PerRs require a structural metal for proper dimeric assembly...
November 16, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/29143694/cryo-scanning-electron-microscopy-sem-and-scanning-transmission-electron-microscopy-stem-in-sem-for-bio-and-organo-mineral-interface-characterization-in-the-environment
#3
Guillaume Wille, Jennifer Hellal, Patrick Ollivier, Annie Richard, Agnes Burel, Louis Jolly, Marc Crampon, Caroline Michel
Understanding biofilm interactions with surrounding substratum and pollutants/particles can benefit from the application of existing microscopy tools. Using the example of biofilm interactions with zero-valent iron nanoparticles (nZVI), this study aims to apply various approaches in biofilm preparation and labeling for fluorescent or electron microscopy and energy dispersive X-ray spectrometry (EDS) microanalysis for accurate observations. According to the targeted microscopy method, biofilms were sampled as flocs or attached biofilm, submitted to labeling using 4',6-diamidino-2-phenylindol, lectins PNA and ConA coupled to fluorescent dye or gold nanoparticles, and prepared for observation (fixation, cross-section, freezing, ultramicrotomy)...
November 16, 2017: Microscopy and Microanalysis
https://www.readbyqxmd.com/read/29142288/identification-of-small-rnas-abundant-in-burkholderia-cenocepacia-biofilms-reveal-putative-regulators-with-a-potential-role-in-carbon-and-iron-metabolism
#4
Andrea Sass, Sanne Kiekens, Tom Coenye
Small RNAs play a regulatory role in many central metabolic processes of bacteria, as well as in developmental processes such as biofilm formation. Small RNAs of Burkholderia cenocepacia, an opportunistic pathogenic beta-proteobacterium, are to date not well characterised. To address that, we performed genome-wide transcriptome structure analysis of biofilm grown B. cenocepacia J2315. 41 unannotated short transcripts were identified in intergenic regions of the B. cenocepacia genome. 15 of these short transcripts, highly abundant in biofilms, widely conserved in Burkholderia sp...
November 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29138908/amine-modified-magnetic-iron-oxide-nanoparticle-as-a-promising-carrier-for-application-in-bio-self-healing-concrete
#5
Mostafa Seifan, Alireza Ebrahiminezhad, Younes Ghasemi, Ali Khajeh Samani, Aydin Berenjian
Self-healing mechanisms are a promising solution to address the concrete cracking issue. Among the investigated self-healing strategies, the biotechnological approach is distinguished itself by inducing the most compatible material with concrete composition. In this method, the potent bacteria and nutrients are incorporated into the concrete matrix. Once cracking occurs, the bacteria will be activated, and the induced CaCO3 crystals will seal the concrete cracks. However, the effectiveness of a bio self-healing concrete strictly depends on the viability of bacteria...
November 14, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/29137641/improving-e-coli-growth-performance-by-manipulating-small-rna-expression
#6
REVIEW
Alejandro Negrete, Joseph Shiloach
Efficient growth of E. coli, especially for production of recombinant proteins, has been a challenge for the biotechnological industry since the early 1970s. By employing multiple approaches, such as different media composition, various growth strategies and specific genetic manipulations, it is now possible to grow bacteria to concentrations exceeding 100 g/L and to achieve high concentrations of recombinant proteins. Although the growth conditions are carefully monitored and maintained, it is likely that during the growth process cells are exposed to periodic stress conditions, created by fluctuations in pH, dissolved oxygen, temperature, glucose, and salt concentration...
November 14, 2017: Microbial Cell Factories
https://www.readbyqxmd.com/read/29135009/bacterial-species-identifiable-magnetic-nanosystems-for-early-sepsis-diagnosis-and-extracorporeal-photodynamic-blood-disinfection
#7
Jianhao Wang, Hao Wu, Yanmei Yang, Rong Yan, Yuan Zhao, Yanhao Wang, Aihong Chen, Shilong Shao, Pengju Jiang, Yong-Qiang Li
Despite the numerous bacteria detection and elimination techniques available nowadays, sensitive diagnosis and treatment of sepsis (caused by the presence of bacteria in the bloodstream), especially at the early stage, remain big challenges. Here we report a nanosystem for early sepsis diagnosis and complete extracorporeal blood disinfection, based on iron oxide magnetic nanoparticles functionalized with chlorin e6 molecules and bacterial species-identifiable aptamers (Fe3O4-Ce6-Apt). We demonstrate that the Fe3O4-Ce6-Apt nanosystem can achieve simultaneous blood bacterial species identification and enrichment in a single step, and the enriched bacteria can be easily detected with the assistance of fluorescence microscopic determination...
November 14, 2017: Nanoscale
https://www.readbyqxmd.com/read/29129658/overcoming-antibiotic-resistance-is-siderophore-trojan-horse-conjugation-an-answer-to-evolving-resistance-in-microbial-pathogens
#8
REVIEW
Kalyani Dhusia, Archana Bajpai, P W Ramteke
Comparative study of siderophore biosynthesis pathway in pathogens provides potential targets for antibiotics and host drug delivery as a part of computationally feasible microbial therapy. Iron acquisition using siderophore models is an essential and well established model in all microorganisms and microbial infections a known to cause great havoc to both plant and animal. Rapid development of antibiotic resistance in bacterial as well as fungal pathogens has drawn us at a verge where one has to get rid of the traditional way of obstructing pathogen using single or multiple antibiotic/chemical inhibitors or drugs...
November 10, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
https://www.readbyqxmd.com/read/29128766/low-biodegradability-of-dissolved-organic-matter-and-trace-metals-from-subarctic-waters
#9
Olga V Oleinikova, Liudmila S Shirokova, Olga Y Drozdova, Sergey A Lapitskiy, Oleg S Pokrovsky
The heterotrophic mineralization of dissolved organic matter (DOM) controls the CO2 flux from the inland waters to the atmosphere, especially in the boreal waters, although the mechanisms of this process and the fate of trace metals associated with DOM remain poorly understood. We studied the interaction of culturable aquatic (Pseudomonas saponiphila) and soil (Pseudomonas aureofaciens) Gammaproteobacteria with seven different organic substrates collected in subarctic settings. These included peat leachate, pine crown throughfall, fen, humic lake, stream, river, and oligotrophic lake with variable dissolved organic carbon (DOC) concentrations (from 4 to 60mgL(-1))...
November 9, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/29127928/native-hypersaline-sulphate-reducing-bacteria-contributes-to-iron-nanoparticle-formation-in-saltpan-sediment-a-concern-for-aquaculture
#10
Kirti Ranjan Das, Meenal Kowshik, M K Praveen Kumar, Savita Kerkar, S K Shyama, Samir Mishra
A hypersaline dissimilatory sulphate reducing bacterium, strain LS4, isolated from the sediments of Ribander saltpan, Goa, India was found to produce (Fe2O3) maghemite nanoparticles. The presence of maghemite nanoparticles was also detected in the same sediment. Strain LS4 was isolated anaerobically on modified Hatchikian's media at 300 psu, growing optimally at 30 °C, 150 psu salinity and pH 7.8. Based on biochemical characteristics and 16S rRNA sequence analysis, the strain LS4 belongs to genus Desulfovibrio...
November 8, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/29126700/structure-and-function-of-haemoglobins
#11
REVIEW
David A Gell
Haemoglobin (Hb) is widely known as the iron-containing protein in blood that is essential for O2 transport in mammals. Less widely recognised is that erythrocyte Hb belongs to a large family of Hb proteins with members distributed across all three domains of life-bacteria, archaea and eukaryotes. This review, aimed chiefly at researchers new to the field, attempts a broad overview of the diversity, and common features, in Hb structure and function. Topics include structural and functional classification of Hbs; principles of O2 binding affinity and selectivity between O2/NO/CO and other small ligands; hexacoordinate (containing bis-imidazole coordinated haem) Hbs; bacterial truncated Hbs; flavohaemoglobins; enzymatic reactions of Hbs with bioactive gases, particularly NO, and protection from nitrosative stress; and, sensor Hbs...
October 31, 2017: Blood Cells, Molecules & Diseases
https://www.readbyqxmd.com/read/29126024/nitrate-attenuation-in-low-permeability-sediments-based-on-isotopic-and-microbial-analyses
#12
Yuexia Wu, Ligang Xu, Sai Wang, Zhenglu Wang, Jianying Shang, Xiqing Li, Chunmiao Zheng
This study investigated nitrate attenuation in low-permeability sediments (LPS) in a multi-layer aquifer by integrating hydrochemical, isotopic and microbiological molecular techniques in a field site. In the meantime, the overlying high-permeability sediment (HPS) was also examined on the nitrate attenuation for the sake of comparison. Additionally, laboratory flow-through experiments were conducted to assess the overall nitrate reduction rate in the two types of sediment. The δ(15)N-NO3(-) and δ(34)S-SO4(2-) values were more enriched by approximately 37‰ and 15‰ in the LPS than the overlying HPS associated with substantial reductions of the NO3(-) and SO4(2-) concentration, indicating the occurrence of strong bio-reductions in nitrate and sulfate...
November 7, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/29120125/risk-factors-associated-with-black-tooth-stain
#13
Katica Prskalo, Eva Klarić Sever, Ivan Alerić, Tatjana Antonić Jelić, Ivona Žaja
The aim of the study was to show whether there is any influence of food, drink or drug intake on the formation of tooth discoloration. A total of 500 patients aged 15-25 years were examined to take part in the study. Of these, 60 patients were selected and divided into two groups of 30 patients each. Group 1 included patients with black pigmentation on vestibular/oral tooth surfaces. Group 2 included patients without discoloration (control). Data were recorded in a questionnaire. Atomic absorption spectrometry was used to determine elements in discoloration samples...
March 2017: Acta Clinica Croatica
https://www.readbyqxmd.com/read/29113077/the-oligomeric-form-of-the-escherichia-coli-dps-protein-depends-on-the-availability-of-iron-ions
#14
Sergey Antipov, Sergey Turishchev, Yuriy Purtov, Uliana Shvyreva, Alexander Sinelnikov, Yuriy Semov, Elena Preobrazhenskaya, Andrey Berezhnoy, Natalia Shusharina, Natalia Novolokina, Viktor Vakhtel, Valeriy Artyukhov, Olga Ozoline
The Dps protein of Escherichia coli, which combines ferroxidase activity and the ability to bind DNA, is effectively used by bacteria to protect their genomes from damage. Both activities depend on the integrity of this multi-subunit protein, which has an inner cavity for iron oxides; however, the diversity of its oligomeric forms has only been studied fragmentarily. Here, we show that iron ions stabilize the dodecameric form of Dps. This was found by electrophoretic fractionation and size exclusion chromatography, which revealed several oligomers in highly purified protein samples and demonstrated their conversion to dodecamers in the presence of 1 mM Mohr's salt...
November 5, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29103647/role-of-microbial-activity-in-fe-iii-hydroxysulfate-mineral-transformations-in-an-acid-mine-drainage-impacted-site-from-the-dabaoshan-mine
#15
Yanping Bao, Chuling Guo, Guining Lu, Xiaoyun Yi, Han Wang, Zhi Dang
Fe(III) hydroxysulfate minerals are secondary minerals commonly found in acid mine drainage (AMD) sites and have a major impact on water and soil quality in these environments. While previous studies showed that the Fe(III) hydroxysulfate mineral transformation could be mediated by some bacterial strains under laboratory conditions, the role of indigenous microbial activity in Fe(III) hydroxysulfate mineral transformation in natural environment has received little attention. In this study, microcosms were constructed with AMD-affected river water and sediment from the Dabaoshan Mine that was either left unamended or enriched with nutrients (lactate, nitrogen, and phosphorus (LNP)) and biosynthetic minerals (schwertmannite or jarosite)...
November 2, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/29101308/impact-of-bacterial-srnas-in-stress-responses
#16
REVIEW
Erik Holmqvist, E Gerhart H Wagner
Bacterial life is harsh and involves numerous environmental and internal challenges that are perceived as stresses. Consequently, adequate responses to survive, cope with, and counteract stress conditions have evolved. In the last few decades, a class of small, non-coding RNAs (sRNAs) has been shown to be involved as key players in stress responses. This review will discuss - primarily from an enterobacterial perspective - selected stress response pathways that involve antisense-type sRNAs. These include themes of how bacteria deal with severe envelope stress, threats of DNA damage, problems with poisoning due to toxic sugar intermediates, issues of iron homeostasis, and nutrient limitation/starvation...
November 3, 2017: Biochemical Society Transactions
https://www.readbyqxmd.com/read/29101195/microbially-mediated-coupling-of-fe-and-n-cycles-by-nitrate-reducing-fe-ii-oxidizing-bacteria-in-littoral-freshwater-sediments
#17
Franziska Schaedler, Cindy Lockwood, Ulf Lueder, Clemens Glombitza, Andreas Kappler, Caroline Schmidt
Nitrate-reducing iron(II)-oxidizing bacteria have been known for approximately 20 years. There has been much debate to which extent the reduction of nitrate and the oxidation of ferrous iron are coupled via enzymatic pathways or via abiotic processes induced by nitrite formed by heterotrophic denitrification. The aim of the present study was to assess the coupling of nitrate reduction and iron(II) oxidation by monitoring changes in substrate concentrations as well as in the activity of nitrate-reducing bacteria in natural littoral freshwater sediment as a response to a stimulation with nitrate and iron(II)...
November 3, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29099689/identification-of-novel-small-rnas-in-burkholderia-cenocepacia-kc-01-expressed-under-iron-limitation-and-oxidative-stress-conditions
#18
Suparna Ghosh, Chetna Dureja, Indu Khatri, Srikrishna Subramanian, Saumya Raychaudhuri, Sagarmoy Ghosh
Small RNA (sRNA)-mediated regulation of gene expression is a major tool to understand bacterial responses to environmental changes. In particular, pathogenic bacteria employ sRNAs to adapt to the host environment and establish infection. Members of the Burkholderia cepacia complex, normally present in soil microbiota, cause nosocomial lung infection especially in hospitalized cystic fibrosis patients. We sequenced the draft genome of Burkholderia cenocepacia KC-01, isolated from the coastal saline soil, and identified several potential sRNAs in silico...
November 3, 2017: Microbiology
https://www.readbyqxmd.com/read/29097322/the-virulence-and-immune-protection-of-edwardsiella-ictaluri-hemr-mutants-in-catfish
#19
Hossam Abdelhamed, Iman Ibrahim, Wes Baumgartner, Mark L Lawrence, Attila Karsi
Edwardsiella ictaluri is a Gram-negative facultative intracellular rod, causing enteric septicemia of catfish (ESC). Several heme uptake systems have been described in bacterial pathogens, most of which involve outer membrane proteins (OMPs). We have shown recently that heme/hemoglobin receptor family protein (HemR) is significantly up-regulated in E. ictaluri under iron-restricted conditions. In this work, our goal was to construct E. ictaluri HemR mutants and assess their virulence and immune protection potentials in catfish...
October 31, 2017: Fish & Shellfish Immunology
https://www.readbyqxmd.com/read/29095994/pyomelanin-produced-by-vibriocholerae-confers-resistance-to-predation-by-acanthamoebacastellanii
#20
Parisa Noorian, Hu Jie, Zhiliang Chen, Staffan Kjelleberg, Marc R Wilkins, Shuyang Sun, Diane McDougald
Protozoan predation is one of the main environmental factors constraining bacterial growth in aquatic environments, and thus has led to the evolution of a number of defence mechanisms that protect bacteria from predation. These mechanisms may also function as virulence factors in infection of animal and human hosts. Whole transcriptome shotgun sequencing of Vibrio cholerae biofilms during predation by the amoebae, Acanthamoeba castellanii, revealed that 131 transcripts were significantly differentially regulated when compared to the non-grazed control...
October 31, 2017: FEMS Microbiology Ecology
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