keyword
MENU ▼
Read by QxMD icon Read
search

gram negative bacteria

keyword
https://www.readbyqxmd.com/read/28335299/synthesis-of-sic-ag-cellulose-nanocomposite-and-its-antibacterial-activity-by-reactive-oxygen-species-generation
#1
Andrzej Borkowski, Tomasz Cłapa, Mateusz Szala, Arkadiusz Gąsiński, Marek Selwet
We describe the synthesis of nanocomposites, based on nanofibers of silicon carbide, silver nanoparticles, and cellulose. Silver nanoparticle synthesis was achieved with chemical reduction using hydrazine by adding two different surfactants to obtain a nanocomposite with silver nanoparticles of different diameters. Determination of antibacterial activity was based on respiration tests. Enzymatic analysis indicates oxidative stress, and viability testing was conducted using an epifluorescence microscope. Strong bactericidal activity of nanocomposites was found against bacteria Escherichia coli and Bacillus cereus, which were used in the study as typical Gram-negative and Gram-positive bacteria, respectively...
September 13, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335288/biosynthesis-of-silver-nanoparticles-using-taxus-yunnanensis-callus-and-their-antibacterial-activity-and-cytotoxicity-in-human-cancer-cells
#2
Qian Hua Xia, Yan Jun Ma, Jian Wen Wang
Plant constituents could act as chelating/reducing or capping agents for synthesis of silver nanoparticles (AgNPs). The green synthesis of AgNPs has been considered as an environmental friendly and cost-effective alternative to other fabrication methods. The present work described the biosynthesis of AgNPs using callus extracts from Taxus yunnanensis and evaluated their antibacterial activities in vitro and potential cytotoxicity in cancer cells. Callus extracts were able to reduce silver nitrate at 1 mM in 10 min...
September 1, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335201/size-and-shape-dependent-antibacterial-studies-of-silver-nanoparticles-synthesized-by-wet-chemical-routes
#3
Muhammad Akram Raza, Zakia Kanwal, Anum Rauf, Anjum Nasim Sabri, Saira Riaz, Shahzad Naseem
Silver nanoparticles (AgNPs) of different shapes and sizes were prepared by solution-based chemical reduction routes. Silver nitrate was used as a precursor, tri-sodium citrate (TSC) and sodium borohydride as reducing agents, while polyvinylpyrrolidone (PVP) was used as a stabilizing agent. The morphology, size, and structural properties of obtained nanoparticles were characterized by scanning electron microscopy (SEM), UV-visible spectroscopy (UV-VIS), and X-ray diffraction (XRD) techniques. Spherical AgNPs, as depicted by SEM, were found to have diameters in the range of 15 to 90 nm while lengths of the edges of the triangular particles were about 150 nm...
April 15, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335198/gold-nanoparticles-an-efficient-antimicrobial-agent-against-enteric-bacterial-human-pathogen
#4
Shahzadi Shamaila, Noshin Zafar, Saira Riaz, Rehana Sharif, Jawad Nazir, Shahzad Naseem
Enteric bacterial human pathogens, i.e., Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Klebsiella pneumoniae, are the major cause of diarrheal infections in children and adults. Their structure badly affects the human immune system. It is important to explore new antibacterial agents instead of antibiotics for treatment. This project is an attempt to explain how gold nanoparticles affect these bacteria. We investigated the important role of the mean particle size, and the inhibition of a bacterium is dose-dependent...
April 14, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28334702/in-vitro-antibacterial-activity-of-7-substituted-6-fluoroquinolone-and-7-substituted-6-8-difluoroquinolone-derivatives
#5
Socorro Leyva-Ramos, Denisse de Loera, Jaime Cardoso-Ortiz
BACKGROUND: Fluoroquinolones are widely prescribed synthetic antimicrobial agents. Quinolones act by converting their targets, gyrase and topoisomerase IV, into toxic enzymes that fragment the bacterial chromosome; the irreversible DNA damage eventually causes the killing of bacteria. Thorough knowledge of the structure-activity relationship of quinolones is essential for the development of new drugs with improved activity against resistant strains. METHODS: The compounds were screened for their antibacterial activity against 4 representing strains using the Kirby-Bauer disk diffusion method...
March 24, 2017: Chemotherapy
https://www.readbyqxmd.com/read/28334005/multi-scale-model-of-drug-induced-adaptive-resistance-of-gram-negative-bacteria-to-polymyxin-b
#6
Wojciech Krzyzanski, Gauri G Rao
The purpose of this report is to apply multi-scale modeling using the theory of physiologically structured populations (PSP) to develop a mathematical model for antimicrobial resistance based on a heterogeneous distribution of receptors and affinities among bacterial cells. The theory has been tested on data obtained from an in vitro static time-kill infection model analyzing the pharmacodynamics of polymyxin B against Gram-negative bacteria. The drug binding parameter KD (dissociation equilibrium constant) is assumed to vary between the bacterial cells...
2017: PloS One
https://www.readbyqxmd.com/read/28333363/evaluation-of-the-%C3%AE-carba%C3%A2-test-a-colorimetric-test-for-the-rapid-detection-of-carbapenemase-activity-in-gram-negative-bacilli
#7
Sandrine Bernabeu, Laurent Dortet, Thierry Naas
Objectives: There is an urgent need for accurate and fast diagnostic tests to identify carbapenemase-producing bacteria. Here, we have evaluated a novel colorimetric test (the β-CARBA™ test; Bio-Rad) to detect carbapenemase-producing Gram-negative bacilli from cultured colonies. Methods: The performance of the β-CARBA™ test was compared with that of the Carba NP test (or the CarbAcineto NP test) and RAPIDEC ® CARBA NP (bioMérieux) using a collection of 290 isolates with characterized β-lactamase content...
March 10, 2017: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/28333237/new-paenibacillus-strain-produces-a-family-of-linear-and-cyclic-antimicrobial-lipopeptides-cyclization-is-not-essential-for-their-antimicrobial-activity
#8
En Huang, Xu Yang, Liwen Zhang, Sun Hee Moon, Ahmed E Yousef
A new bacterial isolate, Paenibacillus sp. OSY-N, showed potent antimicrobial activity against Gram-negative and Gram-positive bacteria. Antimicrobials produced by this strain were purified by reverse-phase high performance liquid chromatography (HPLC). Structural analysis, using mass spectrometry (MS), of a single active HPLC fraction revealed two known cyclic lipopeptides, BMY-28160 and permetin A, a new cyclic lipopeptide, and the linear counterparts of these cyclic compounds. The latter were designated as paenipeptin A, B and C, respectively...
February 25, 2017: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/28333234/horizontal-transfer-of-the-blandm-1-gene-to-pseudomonas-aeruginosa-and-acinetobacter-baumannii-in-biofilms
#9
Windy D Tanner, Robyn M Atkinson, Ramesh K Goel, Mark A Toleman, Lowell Scott Benson, Christina A Porucznik, James A VanDerslice
Horizontal gene transfer has contributed to the global spread of the blaNDM-1 gene. Multiple studies have demonstrated plasmid transfer of blaNDM-1 between Gram-negative bacteria, primarily Enterobacteriaceae species, but conjugational transfer of natural blaNDM-1 plasmids from Enterobacteriaceae into Pseudomonas aeruginosa and Acinetobacter baumannii has not previously been shown. As P. aeruginosa and A. baumannii are both typically strong biofilm-formers, transfer of natural blaNDM-1 plasmids could potentially occur more readily in this environment...
February 25, 2017: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/28332827/subcellular-chemical-imaging-of-antibiotics-in-single-bacteria-using-c60-secondary-ion-mass-spectrometry
#10
Hua Tian, David A Six, Thomas Krucker, Jennifer A Leeds, Nicholas Winograd
The inherent difficulty of discovering new and effective antibacterials and the rapid development of resistance particularly in Gram-negative bacteria, illustrates the urgent need for new methods that enable rational drug design. Here we report the development of 3D imaging cluster secondary ion mass spectrometry (SIMS) as a label-free approach to chemically map small molecules in aggregated and single Escherichia coli cells, with ~300 nm spatial resolution and high chemical sensitivity. The feasibility of quantitative analysis was explored, and a non-linear relationship between treatment dose and signal for tetracycline and ampicillin, two clinically-used antibacterials, was observed...
March 23, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28332591/improved-lysis-efficiency-and-immunogenicity-of-salmonella-ghosts-mediated-by-co-expression-of-%C3%AE-phage-holin-endolysin-and-%C3%A9-x174-gene-e
#11
Gayeon Won, Irshad Ahmed Hajam, John Hwa Lee
Bacterial ghosts (BGs) are empty cell envelopes derived from Gram-negative bacteria by bacteriophage ɸX174 gene E mediated lysis. They represent a novel inactivated vaccine platform; however, the practical application of BGs for human vaccines seems to be limited due to the safety concerns on the presence of viable cells in BGs. Therefore, to improve the lysis efficiency of the gene E, we exploited the peptidoglycan hydrolyzing ability of the λ phage holin-endolysins to expedite the process of current BG production system...
March 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28331609/preparation-characterization-antimicrobial-and-cytotoxicity-studies-of-copper-zinc-loaded-montmorillonite
#12
Lefei Jiao, Fanghui Lin, Shuting Cao, Chunchun Wang, Huan Wu, Miaoan Shu, Caihong Hu
BACKGROUND: A series of modified montmorillonites (Mt) including zinc-loaded Mt (Zn-Mt), copper-loaded Mt (Cu-Mt), copper/zinc-loaded Mt with different Cu/Zn ratio (Cu/Zn-Mt-1, Cu/Zn-Mt-2, Cu/Zn-Mt-3) were prepared by an ion-exchange reaction, and characterized using X-ray diffraction (XRD), fourier transformed infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The specific surface areas, antimicrobial activity and cytotoxicity of the modified Mt were investigated...
2017: Journal of Animal Science and Biotechnology
https://www.readbyqxmd.com/read/28331079/characterization-and-vaccine-potential-of-membrane-vesicles-produced-by-francisella-noatunensis-sup-orientalis-in-an-adult-zebrafish-model
#13
Leidy Lagos, Julia I Tandberg, Urska Repnik, Preben Boysen, Erik Ropstad, Deepa Varkey, Ian T Paulsen, Hanne C Winther-Larsen
Vaccine development against extracellular bacteria has been important for the sustainability of the aquaculture industry. In contrast, infections with intracellular pathogens remain largely an unresolved problem. Francisella noatunensis subspecies orientalis (Fno) are Gram-negative, facultative intracellular bacteria that cause the disease francisellosis in fish. Francisellosis is commonly characterized as a chronic granulomatous disease with high morbidity and can result in high mortality depending on the host...
March 22, 2017: Clinical and Vaccine Immunology: CVI
https://www.readbyqxmd.com/read/28330748/control-of-biofilm-forming-clinically-important-bacteria-by-green-synthesized-zno-nanoparticles-and-its-ecotoxicity-on-ceriodaphnia-cornuta
#14
Sekar Vijayakumar, Balasubramanian Malaikozhundan, Sathappan Shanthi, Baskaralingam Vaseeharan, Nooruddin Thajuddin
Zinc oxide nanoparticles were synthesized using the aqueous leaf extracts of Plectranthus barbatus (Plb-ZnO NPs) and characterized by UV-visible spectroscopy, XRD, FTIR. SEM and EDS and UV-visible spectra recorded the absorbance peak of Plb-ZnO NPs at 343 nm. SEM analyses showed the spherical shape of Plb-ZnO NPs with the particle size between 30 and 60 nm. Plb-ZnO NPs exhibited antibacterial and antibiofilm activity against Gram positive Bacillus subtilis at all tested concentrations. In contrast, Plb-ZnO NPs showed antibacterial and antibiofilm activity against Gram negative Vibrio parahaemolyticus and Proteus vulgaris at 100 μg/ml...
March 18, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28330333/extraction-and-bioactive-profile-of-the-compounds-produced-by-rhodococcus-sp-vld-10
#15
Bokka Yellamanda, Muvva Vijayalakshmi, Alapati Kavitha, Dorigondla Kumar Reddy, Yenamandra Venkateswarlu
A potent actinobacterial strain isolated from the marine samples of Bheemunipatnam beach, Visakhapatnam, India, was identified as Rhodococcus sp. VLD-10 using the conventional and genomic (16S rRNA) approaches. Bioactive compounds responsible for the antimicrobial activity of the strain were elucidated by cultivating the strain VLD-10 in a modified yeast extract-malt extract-lactose broth followed by subsequent chromatographic and spectroscopic analyses. Extraction, purification, and structural confirmation of five compounds, viz...
December 2016: 3 Biotech
https://www.readbyqxmd.com/read/28330268/antimicrobial-activity-of-pvp-coated-silver-nanoparticles-synthesized-by-lysinibacillus-varians
#16
Divya Bhatia, Ashwani Mittal, Deepak Kumar Malik
Emergence of resistant microbes to conventional antibiotics and increased emphasis on health-care costs has raised the concern for the development of new effective antimicrobial reagents. Silver nanoparticles being an excellent broad-spectrum antibacterial agent could be considered as a suitable alternative for existing antibiotic. This study demonstrates the extra-cellular synthesis of stable silver nanoparticles using supernatant of Lysinibacillus varians. The synthesized silver nanoparticles were characterized by using UV-visible spectrum analysis, X-ray diffraction, Transmission electron microscopy (TEM) and FT-IR analysis...
December 2016: 3 Biotech
https://www.readbyqxmd.com/read/28330218/bacterial-carrageenases-an-overview-of-production-and-biotechnological-applications
#17
REVIEW
Prakram Singh Chauhan, Arunika Saxena
Carrageenan, one of the phycocolloids is a sulfated galactan made up of linear chains of galactose and 3,6-anhydrogalactose with alternating α-(1 → 3) and β-(1 → 4) linkages and further classified based on the number and the position of sulfated ester(s); κ-, ι- and λ-carrageenan. Enzymes which degrade carrageenans are called k-, ι-, and λ-carrageenases. They all are endohydrolases that cleave the internal β-(1-4) linkages of carrageenans yielding products of the oligo-carrageenans. These enzymes are produced only by bacteria specifically gram negative bacteria...
December 2016: 3 Biotech
https://www.readbyqxmd.com/read/28330204/endophytic-fungal-isolate-mediated-biosynthesis-of-silver-nanoparticles-and-their-free-radical-scavenging-activity-and-anti-microbial-studies
#18
Vasudeva Reddy Netala, Venkata Subbaiah Kotakadi, Pushpalatha Bobbu, Susmila Aparna Gaddam, Vijaya Tartte
The present study reports that the biosynthesis of AgNPs using an endophytic fungus isolated from the ethnomedicinal plant Centella asiatica. The endophytic fungus was identified as Aspergillus versicolor ENT7 based on 18S rRNA gene sequencing (NCBI Accession number KF493864). The AgNPs synthesized were characterized by UV-visible spectroscopy, Fourier transform infra-red spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD), particle size analyzer, and zeta potential measurements...
December 2016: 3 Biotech
https://www.readbyqxmd.com/read/28330162/evaluation-of-silver-nanoparticles-synthetic-potential-of-couroupita-guianensis-aubl-flower-buds-extract-and-their-synergistic-antibacterial-activity
#19
T Venkata Rajesh Kumar, J S R Murthy, Madamsetti Narayana Rao, Y Bhargava
The present investigation demonstrates Couroupita guianensis flower buds extract mediated synthesis of stable silver nanoparticles (AgNPs). Instant formation of AgNPs was primarily confirmed by the appearance of yellowish brown colour and characteristic silver SPR band in the UV-visible spectrum. Elemental and crystalline natures of the AgNPs were identified from EDX and XRD pattern, respectively. Spherical morphology and the mono-disparity were revealed from TEM and AFM images. The particle size ranged from 5 to 30 nm and average size of 17 nm was consistent in XRD, TEM and AFM measurements...
June 2016: 3 Biotech
https://www.readbyqxmd.com/read/28330121/optimization-study-of-2-hydroxyquinoxaline-2-hq-biodegradation-by-ochrobactrum-sp-hq1
#20
G V Subba Reddy, M Md Rafi, S Rubesh Kumar, N Khayalethu, D Muralidhara Rao, B Manjunatha, G H Philip, B R Reddy
A novel aerobic gram-negative bacterial strain capable of utilizing 2-hydroxyquinoxaline (2-HQ) as sole source of carbon and energy was isolated from Indian agricultural soil and named as HQ1. Strain HQ1 was identified as Ochrobactrum sp. on the basis of morphology, physico-biochemical characteristics and 16S rRNA sequence analysis. The generation time of Ochrobactrum sp. HQ1 on 2-HQ at log phase is 0.71 h or 42.6 min. The degradation of 2-HQ by HQ1 under various physico-chemical parameters was analysed by HPLC and observed to be optimum with a high inoculum density (1...
June 2016: 3 Biotech
keyword
keyword
224
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"