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Antibacterial activity

Fatemeh Kiani, Negar Ashari Astani, Reza Rahighi, Ahmad Tayyebi, Meysam Tayebi, Jafar Khezri, Ehsan Hashemi, Ursula Rothlisberger, Abdolreza Simchi
In the present work, the effect of graphene oxide (GO) nanosheets on the antibacterial activity of CuO nanowire arrays under visible light irradiation is shown. A combined thermal oxidation/electrophoretic deposition technique was employed to prepare three-dimensional networks of graphene oxide nanosheets hybridized with vertically aligned CuO nanowires. With the help of standard antibacterial assays and X-ray photoelectron spectroscopy, it is shown that the light-activated antibacterial response of the hybrid material against gram-negative Escherichia coli is significantly improved as the oxide functional groups of the GO nanosheets are reduced...
March 7, 2018: Journal of Colloid and Interface Science
Cornelia Wiegand, Andrea Völpel, Andrea Ewald, Markko Remesch, Jan Kuever, Janine Bauer, Stefanie Griesheim, Carolin Hauser, Julian Thielmann, Silke Tonndorf-Martini, Bernd W Sigusch, Jürgen Weisser, Ralf Wyrwa, Peter Elsner, Uta-Christina Hipler, Martin Roth, Carolin Dewald, Claudia Lüdecke-Beyer, Jörg Bossert
Bactericidal materials gained interest in the health care sector as they are capable of preventing material surfaces from microbial colonization and subsequent spread of infections. However, commercialization of antimicrobial materials requires proof of their efficacy, which is usually done using in vitro methods. The ISO 22196 standard (Japanese test method JIS Z 2801) is a method for measuring the antibacterial activity of daily goods. As it was found reliable for testing the biocidal activity of antimicrobially active materials and surface coatings most of the laboratories participating in this study used this protocol...
2018: PloS One
Jacqueline M Zaengle-Barone, Abigail C Jackson, David M Besse, Bradford Becken, Mehreen Arshad, Patrick C Seed, Katherine J Franz
The unabated rise in bacterial resistance to conventional antibiotics, coupled with collateral damage to normal flora incurred by overuse of broad-spectrum antibiotics, necessitates the development of new antimicrobials targeted against pathogenic organisms. Here, we explore the antibacterial outcomes and mode of action of a prochelator that exploits the production of β-lactamase enzymes by drug-resistant bacteria to convert a non-toxic compound into a metal-binding antimicrobial agent directly within the microenvironment of pathogenic organisms...
March 20, 2018: ACS Infectious Diseases
Maja Cindrić, Mihaela Perić, Marijeta Kralj, Irena Martin-Kleiner, Marie-Hélène David-Cordonnier, Hana Čipčić Paljetak, Mario Matijašić, Donatella Verbanac, Grace Karminski-Zamola, Marijana Hranjec
Novel nitro (3a-3f)- and amino (4a-4f and 5a-5f)-substituted 2-benzimidazolyl and 2-benzothiazolyl benzo[b]thieno-2-carboxamides were designed and synthesized as potential antibacterial agents. The antibacterial activity of these compounds has been evaluated against Gram-positive (Staphylococcus aureus and Enterococcus faecalis) and Gram-negative bacteria (Escherichia coli and Moraxella catarrhalis). The most promising antibacterial activity was observed for the nitro- and amino-substituted benzimidazole derivatives 3a, 4a, 5a and 5b with MICs 2-8 [Formula: see text]...
March 20, 2018: Molecular Diversity
P Petkov, R Marinova, V Kochev, N Ilieva, E Lilkova, L Litov
Antimicrobial peptides (AMPs) play crucial role as mediators of the primary host defence against microbial invasion. They are considered a promising alternative to antibiotics for multidrug resistant bacterial strains. For complete understanding of the antimicrobial defence mechanism, a detailed knowledge of the dynamics of peptide-membrane interactions, including atomistic studies on AMPs geometry and both peptide and membrane structural changes during the whole process is a prerequisite. We aim at clarifying the conformation dynamics of small linear AMPs in solution as a first step of in silico protocol for establishing a correspondence between certain amino-acid sequence motifs, secondary-structure elements, conformational dynamics in solution and the intensity and mode of interaction with the bacterial membrane...
March 20, 2018: Journal of Biomolecular Structure & Dynamics
Yang Si, Zheng Zhang, Wanrong Wu, Qiuxia Fu, Kang Huang, Nitin Nitin, Bin Ding, Gang Sun
Emerging infectious diseases (EIDs) are a significant burden on global economies and public health. Most present personal protective equipment used to prevent EID transmission and infections is typically devoid of antimicrobial activity. We report on green bioprotective nanofibrous membranes (RNMs) with rechargeable antibacterial and antiviral activities that can effectively produce biocidal reactive oxygen species (ROS) solely driven by the daylight. The premise of the design is that the photoactive RNMs can store the biocidal activity under light irradiation and readily release ROS under dim light or dark conditions, making the biocidal function "always online...
March 2018: Science Advances
Tang Gao, Hongliang Zeng, Huan Xu, Feng Gao, Wei Li, Shengwang Zhang, Yi Liu, Guifang Luo, Mingdan Li, Dejian Jiang, Zhigao Chen, Yong Wu, Wei Wang, Wenbin Zeng
Background: Increasing bacterial infections as well as a rise in bacterial resistance call for the development of novel and safe antimicrobial agents without inducing bacterial resistance. Nanoparticles (NPs) present some advantages in treating bacterial infections and provide an alternative strategy to discover new antibiotics. Here, we report the development of novel self-assembled fluorescent organic nanoparticles ( FONs ) with excellent antibacterial efficacy and good biocompatibility. Methods: Self-assembly of 1-(12-(pyridin-1-ium-1-yl)dodecyl)-4-(1,4,5-triphenyl-1H-imidazol-2-yl)pyridin-1-ium (TPIP) in aqueous solution was investigated using dynamic light scattering (DLS) and transmission electron microscopy (TEM)...
2018: Theranostics
Tanzeel Ur Rehman, Arif-Ullah Khan, Azar Abbas, Javid Hussain, Farman Ullah Khan, Kimberly Stieglitz, Shamsher Ali
In the present study, we describe various pharmacological effects and computational analysis of nepetolide, a tricyclic clerodane-type diterpene, isolated from Nepeta suavis . Nepetolide concentration-dependently (1.0-1000 µg/mL) exhibited 1,1-diphenyl,2-picrylhydrazyl free radical scavenging activity with maximum effect of 87.01 ± 1.85%, indicating its antioxidant potential, as shown by standard drug, ascorbic acid. It was moderately active against bacterial strain of Staphylococcus aureus . In brine shrimp's lethality model, nepetolide potently showed cytotoxic effect, with LC50 value of 8...
March 2018: Saudi Pharmaceutical Journal: SPJ: the Official Publication of the Saudi Pharmaceutical Society
Kieu-Nhi Tran, Michael J Rybak
Background: Increasing utilization of vancomycin due to the high prevalence of methicillin-resistant S. aureus (MRSA) infections has lead to the emergence of vancomycin-intermediate S. aureus (VISA) and heterogeneous VISA (hVISA). In vitro data suggest the potential for potent synergy between several beta-lactams and vancomycin. The objective of this study is to evaluate the synergy between beta-lactams and vancomycin against MRSA that is vancomycin susceptible, vancomycin susceptible Staphylococcus aureus (VSSA), hVISA, and VISA...
March 19, 2018: Antimicrobial Agents and Chemotherapy
Jin Qu, Xin Zhao, Peter X Ma, Baolin Guo
Injectable hydrogels with multistimuli responsiveness to electrical field and pH as a drug delivery system have been rarely reported. Herein, we developed a series of injectable conductive hydrogels as "smart" drug carrier with the properties of electro-responsiveness, pH-sensitivity, and inherent antibacterial activity. The hydrogels were prepared by mixing chitosan-graft-polyaniline (CP) copolymer and oxidized dextran (OD) as a cross-linker. The chemical structures, morphologies, electrochemical property, swelling ratio, conductivity, rheological property, in vitro and in vivo biodegradation, and gelation time of hydrogels were characterized...
March 16, 2018: Acta Biomaterialia
Shadpour Mallakpour, Soheila Mansourzadeh
The aim of this paper was to blend the polymers, poly(N-vinyl-2-pyrrolidone) (PVP) and poly(vinyl alcohol) (PVA) to produce a novel composite materials possessing the benefits of both. CuO nanoparticles (NPs) were used as a suitable filler to fabricate the blend nanocomposites (NCs) with desired properties. First, the surface of NPs, was modified with vitamin B1 (VB1 ) as a bio-safe coupling agent. Then, the blend NCs with various ratios of modified CuO (3, 5, and 7 wt%) were fabricated under ultrasonic irradiations followed by casting/solvent evaporation method...
May 2018: Ultrasonics Sonochemistry
Chin-Chuan Tsai, Chi-Shiuan Lin, Chun-Ru Hsu, Chiu-Ming Chang, I-Wei Chang, Li-Wei Lin, Chih-Hsin Hung, Jiun-Ling Wang
BACKGROUND: No animal model studies have been conducted in which the efficacy of herbal compounds has been tested against multidrug-resistant Acinetobacter baumannii infections. Very few antibiotics are available for the treatment of pulmonary infections caused by extensively drug-resistant Acinetobacter baumannii (XDRAB). To find alternative treatments, traditional Chinese herbs were screened for their antimicrobial potential. METHODS: The present study screened 30 herbs that are traditionally used in Taiwan and that are commonly prescribed for heat clearing and detoxification...
March 20, 2018: BMC Complementary and Alternative Medicine
Ledys S Copete-Pertuz, Jersson Plácido, Efraím A Serna-Galvis, Ricardo A Torres-Palma, Amanda Mora
In this work, Leptosphaerulina sp. (a Colombian native fungus) significantly removed three Isoxazolyl-Penicillin antibiotics (IP): oxacillin (OXA, 16000 μg L-1 ), cloxacillin (CLX, 17500 μg L-1 ) and dicloxacillin (DCX, 19000 μg L-1 ) from water. The biological treatment was performed at pH 5.6, 28 °C, and 160 rpm for 15 days. The biotransformation process and lack of toxicity of the final solutions (antibacterial activity (AA) and cytotoxicity) were tested. The role of enzymes in IP removal was analysed through in vitro studies with enzymatic extracts (crude and pre-purified) from Leptosphaerulina sp...
March 2, 2018: Science of the Total Environment
Yong Liu, Lijian Ding, Fang Fang, Shan He
One novel 7-membered lactone derivative, penicillilactone A (1), together with two known compounds, rugulosin A (2) and rugulosin (3) were isolated from the sponge-derived fungus Penicillium sp. LS54. Their structures were elucidated on the basis of spectroscopic analysis and comparison with literature data. Remarkably, penicillilactone A (1) is the first natural product containing a 7-membered lactone ring fused with a furan core. Penicillilactone A (1) exhibited moderate antibacterial activity against aquatic pathogen Vibrio harveyi with an MIC value of 8 μg/mL...
March 19, 2018: Natural Product Research
Wen-Wen Zhao, Zan Ke, Jing-Yue Wu, Wei Gao, Yang Jie, Yin-Ying Ba, Xia Wu, Xiao-Qing Chen
One new triterpenoid (1) and seven known analogues (2-8) were isolated from the leaves of Ilex hainanensis Merr.. Their structures were established by analysis of their MS, 1D and 2D NMR spectroscopic data and comparison with those in the literature. The antibacterial activity of compounds 1-8 were evaluated by determination of minimum inhibitory concentration using twofold microdilution broth method against Streptococcus mutans ATCC 25175 (Gram-positive) and Fusobacterium nucleatum ATCC 10953 (Gram-negative)...
March 19, 2018: Natural Product Research
Zheng Cui, Xiachang Wang, Stefan Koppermann, Jon S Thorson, Christian Ducho, Steven G Van Lanen
Muraymycins are nucleoside antibiotics isolated from Streptomyces sp. NRRL 30471 and several mutant strains thereof that were generated by random, chemical mutagenesis. Reinvestigation of two mutant strains using new media conditions led to the isolation of three new muraymycin congeners, named B8, B9, and C6 (1-3), as well as a known muraymycin, C1. Structures of the compounds were elucidated by HRMS and 1D and 2D NMR spectroscopic analyses. Complete 2D NMR assignments for the known muraymycin C1 are also provided for the first time...
March 19, 2018: Journal of Natural Products
Bing Hu, Yang Shen, Jozef Adamcik, Peter Fischer, Mirjam Schneider, Martin J Loessner, Raffaele Mezzenga
Adaptable hydrogel networks with reversible connectivity have emerged as a promising platform for biomedical applications. Synthetic copolymers and Low-Molecular Weight Gelators (LMWG) have been shown to form reversible hydrogels through self-assembly of the molecules driven by self complementary hydrophobic interaction and hydrogen bonding. Here, inspired by the adhesive proteins secreted by mussels, we found that simply adding natural polyphenols, such as epigallocatechin gallate (EGCG) to amyloid fibrils present in the nematic phase, successfully drives the formation of hydrogels through self-assembly of the hybrid supramolecules...
March 19, 2018: ACS Nano
Tomislav Rončević, Damir Vukičević, Nada Ilić, Lucija Krce, Goran Gajski, Marija Tonkić, Ivana Goić-Barišić, Larisa Zoranić, Yogesh Sonavane, Monica Benincasa, Davor Juretić, Ana Maravić, Alessandro Tossi
Antimicrobial peptides often show broad-spectrum activity due to a mechanism based on bacterial membrane disruption, which also reduces development of permanent resistance, a desirable characteristic in view of the escalating multidrug resistance problem. Host cell toxicity however requires design of artificial variants of natural AMPs to increase selectivity and reduce side effects. Kiadins were designed using rules obtained from natural peptides active against E. coli and a validated computational algorithm based on a training set of such peptides, followed by rational conformational alterations...
March 19, 2018: Journal of Medicinal Chemistry
Jing Li, Wei-Song Kong, Xin Liu, Yong-Qin Geng, Jin Wang, Yong Xu, Xue-Mei Li, Guang-Yu Yang, Min Zhou, Qiu-Fen Hu, Tao Li, Ci-Qing Jiang
A new isoflavone derivative was isolated from Rosa damascena by using various chromatographic techniques including silica gel, Sephadex LH-20, and preparative RP-HPLC separation. Its structure was identified as 4'-hydroxy-7-(3-hydroxypropanoyl)-6-methoxy-isoflavone using combined examinations of their UV, IR, MS, and NMR spectroscopic data. Biological activity test showed that this compound showed prominent antibacterial activity with MIC₉₀ value of (46±4) mg·L⁻¹ for methicillin resistant Staphylococcus aureus(MRSA) strain...
January 2018: Zhongguo Zhong Yao za Zhi, Zhongguo Zhongyao Zazhi, China Journal of Chinese Materia Medica
Gebremedhin Romha, Birhanu Admasu, Tsegaye Hiwot Gebrekidan, Hailelule Aleme, Gebreyohans Gebru
Objective: To evaluate the in vitro antibacterial activities of five plant extracts which have been used as traditional medicines by local healers against three multidrug resistant bacteria, namely, Staphylococcus aureus , Escherichia coli , and Pseudomonas aeruginosa . Results: The highest mean zone of inhibition (4.66 mm) was recorded from methanol extract of Calpurnia aurea (Ait.) Benth. at a concentration of 200 mg/ml against S. aureus , followed by Croton macrostachyus Del...
2018: Evidence-based Complementary and Alternative Medicine: ECAM
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