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Reactive oxygen species bacteria

Vicente Rodríguez-González, Ruth B Domínguez-Espíndola, Sergio Casas-Flores, Olga A Patrón-Soberano, Roberto Camposeco Solis, Soo Wohn Lee
Antifungal silver nanocomposites inspired by titanate nanotubes (AgTNTs) were successfully evaluated for the effective inactivation of the phytopathogenic fungus Botrytis Cinerea within 20 minutes. One dimensional H2Ti3O7 nanotubes functionalized with silver nanoparticles (AgNPs) exhibit unique surface and antifungal properties for the photoinactivation of B. Cinerea. Nanostructured titanates were synthesized by the eco-friendly, practical, microwave-induced, hydrothermal method followed by a highly monodispersive AgNP UV-photodeposition...
October 26, 2016: ACS Applied Materials & Interfaces
Franziska A Mandl, Volker C Kirsch, Ilke Ugur, Elena Kunold, Jan Vomacka, Christian Fetzer, Sabine Schneider, Klaus Richter, Thilo M Fuchs, Iris Antes, Stephan A Sieber
Gram-negative bacteria represent a challenging task for antibacterial drug discovery owing to their impermeable cell membrane and restricted uptake of small molecules. We herein describe the synthesis of natural-product-derived epoxycyclohexenones and explore their antibiotic activity against several pathogenic bacteria. A compound with activity against Salmonella Typhimurium was identified, and the target enzymes were unraveled by quantitative chemical proteomics. Importantly, two protein hits were linked to bacterial stress response, and corresponding assays revealed an elevated susceptibility to reactive oxygen species upon compound treatment...
October 26, 2016: Angewandte Chemie
R E Frye, S Rose, J Chacko, R Wynne, S C Bennuri, J C Slattery, M Tippett, L Delhey, S Melnyk, S G Kahler, D F MacFabe
Propionic acid (PPA) is a ubiquitous short-chain fatty acid, which is a major fermentation product of the enteric microbiome. PPA is a normal intermediate of metabolism and is found in foods, either naturally or as a preservative. PPA and its derivatives have been implicated in both health and disease. Whereas PPA is an energy substrate and has many proposed beneficial effects, it is also associated with human disorders involving mitochondrial dysfunction, including propionic acidemia and autism spectrum disorders (ASDs)...
October 25, 2016: Translational Psychiatry
Yuji Nadatani, Xiaofang Huo, Xi Zhang, Chunhua Yu, Edaire Cheng, Qiuyang Zhang, Kerry B Dunbar, Arianne Theiss, Thai H Pham, David H Wang, Toshio Watanabe, Yasuhiro Fujiwara, Tetsuo Arakawa, Stuart J Spechler, Rhonda F Souza
BACKGROUND & AIMS: Microbial molecular products incite intestinal inflammation by activating Toll-like receptors (TLRs) and inflammasomes of the innate immune system. This system's contribution to esophageal inflammation is not known. Gram-negative bacteria, which dominate the esophageal microbiome in reflux esophagitis, produce lipopolysaccharide (LPS), a TLR4 ligand. TLR4 signaling produces pro-interleukin (IL)1β, pro-IL18, and NOD-like receptor protein 3 (NLRP3), which prime the NLRP3 inflammasome...
July 2016: Cellular and Molecular Gastroenterology and Hepatology
Lingling Zhang, Huan Qi, Zhengxu Yan, Yu Gu, Weiqiang Sun, Abraham Amenay Zewde
The present study evaluated inactivation efficiency of a sonophotocatalytic process using ZnO nanofluids including ultrasonic parameters such as power density, frequency and time. The result showed that inactivation efficiency was increased by 20% when ultrasonic irradiation was combined with photocatalytic process in the presence of natural light. Comparison of inactivation efficiency in photocatalytic, ultrasonic and sonocatalytic processes using Escherichia coli as a model bacteria identified that inactivation efficiencies are shown in the following order: ultrasonic irradiation<sonocatalysis<photocatalysis<sonophotocatalysis...
January 2017: Ultrasonics Sonochemistry
Johnson Lin
Quantification of gene expression of Acinetobacter strain Y under 1000 mg/l of phenol was investigated using qPCR and proteomic analyses. The results show that Acinetobacter strain Y utilized 100 % of phenol within 18 h of exposure. The results of qPCR and proteomic analyses demonstrate a sequential expression of phenol-degrading genes of Acinetobacter strain Y via the ortho-pathway followed by the β-ketoadipate pathway. Many stress-responsive proteins such as chaperones, chaperonins, porins and the enzymes involved in the signal transduction pathway were upregulated especially in the early stage...
October 22, 2016: Archives of Microbiology
Sanjib K Shrestha, Liliia M Kril, Keith D Green, Stefan Kwiatkowski, Vitaliy M Sviripa, Justin R Nickell, Linda P Dwoskin, David S Watt, Sylvie Garneau-Tsodikova
The emergence of multidrug-resistant bacterial and fungal strains poses a threat to human health that requires the design and synthesis of new classes of antimicrobial agents. We evaluated bis(N-amidinohydrazones) and N-(amidino)-N'-aryl-bishydrazones for their antibacterial and antifungal activities against panels of Gram-positive/Gram-negative bacteria as well as fungi. We investigated their potential to develop resistance against both bacteria and fungi by a multi-step resistance-selection method, explored their potential to induce the production of reactive oxygen species, and assessed their toxicity...
October 10, 2016: Bioorganic & Medicinal Chemistry
Troy A Skwor, Stephanie Klemm, Hanyu Zhang, Brianna Schardt, Stephanie Blaszczyk, Matthew A Bork
Increasing rates of antibiotic resistance coupled with the lack of novel antibiotics threatens proper clinical treatment and jeopardizes their use in prevention. A photodynamic approach appears to be an innovative treatment option, even for multi-drug resistant strains of bacteria. Three components are utilized in photodynamic inactivation: a photosensitizer, light source, and oxygen. Variations in photosensitizers strongly influence microbial binding and bactericidal activity. In this study, four different cationic metalloporphyrins (Cu(2+), Fe(2+), Pd(2+), Zn(2+)) were compared to the free-base ligand 5,10,15,20-tetrakis(N-methylpyridinium-4-yl)porphyrin regarding their electronic properties and generation of reactive oxygen species upon subsequent 405nm violet-blue irradiation...
October 15, 2016: Journal of Photochemistry and Photobiology. B, Biology
Sanae Sekihara, Toshio Shibata, Mai Hyakkendani, Shun-Ichiro Kawabata
We recently reported that transglutaminase (TG) suppresses immune deficiency pathway-controlled antimicrobial peptides (IMD-AMPs), thereby conferring immune tolerance to gut microbes, and that RNAi of the TG gene in flies decreases the lifespan compared with non-TG-RNAi flies. Here, analysis of the bacterial composition of the Drosophila gut by next-generation sequencing revealed that gut microbiota comprising one dominant genus of Acetobacter in non-TG-RNAi flies was shifted to that comprising two dominant genera of Acetobacter and Providencia in TG-RNAi flies...
October 19, 2016: Journal of Biological Chemistry
Renata Kurtyka, Wojciech Pokora, Zbigniew Tukaj, Waldemar Karcz
Naphthoquinones are secondary metabolites widely distributed in nature and produced by bacteria, fungi and higher plants. Their biological activity may result from induction of oxidative stress, caused by redox cycling, or direct interaction with cellular macromolecules, in which quinones act as electrophiles. The redox homeostasis is known as one of factors involved in auxin-mediated plant growth regulation. To date, however, little is known about the crosstalk between reactive oxygen species (ROS) produced by quinones and the plant growth hormone auxin (IAA)...
October 19, 2016: AoB Plants
Angela Privat-Maldonado, Deborah O'Connell, Emma Welch, Roddy Vann, Marjan W van der Woude
Low temperature plasmas (LTPs) generate a cocktail of reactive nitrogen and oxygen species (RNOS) with bactericidal activity. The RNOS however are spatially unevenly distributed in the plasma. Here we test the hypothesis that this distribution will affect the mechanisms underpinning plasma bactericidal activity focussing on the level of DNA damage in situ. For the first time, a quantitative, single cell approach was applied to assess the level of DNA damage in bacteria as a function of the radial distance from the centre of the plasma jet...
October 19, 2016: Scientific Reports
Jordan G Sheppard, Timothy E Long
Thiolated fluoroquinolones were synthesized from ciprofloxacin and evaluated for antimicrobial activity against a panel of pathogenic bacteria. Gram-positive species including methicillin-resistant Staphylococcus aureus (MRSA) exhibited the highest level of increased sensitivity toward ciprofloxacin bound with a N-propylthio substituent. Evidence was found that the antibiotics form disulfides with low molecular weight thiols in bacteria and potentiate generation of cytosolic reactive oxygen species (ROS). In final analysis, the enhanced anti-MRSA activity of thiolated fluoroquinolones was attributed to increased cell permeability and reaction with cytosolic thiols that yields an inactive disulfide metabolite and the parent drug ciprofloxacin as an inhibitor of DNA synthesis...
October 4, 2016: Bioorganic & Medicinal Chemistry Letters
Wen-Shuo Kuo, Chia-Yuan Chang, Hua-Han Chen, Chih-Li Lilian Hsu, Jiu-Yao Wang, Hui-Fang Kao, Lawrence Chao-Shan Chou, Yi-Chun Chen, Shean-Jen Chen, Wen-Tsan Chang, Shih-Wen Tseng, Ping-Ching Wu, Ying-Chih Pu
A graphene quantum dot (GQD) used as the photosensitizer with high two-photon absorption in the near-infrared region, a large absolute cross section of two-photon excitation (TPE), strong two-photon luminescence and impressive two-photon stability could be used for dual modality two-photon photodynamic therapy (PDT) and two-photon bioimaging with an ultrashot pulse laser (or defined as TPE). In this study, a GQD efficiently generated reactive oxygen species coupled with TPE, which highly increased the effective PDT ability of both gram-positive and -negative bacteria, with ultra-low energy and an extremely short photoexcitation time generated by TPE...
October 18, 2016: ACS Applied Materials & Interfaces
Marika Rai, David Spratt, Paola R Gomez-Pereira, Jay Patel, Sean P Nair
Oral malodour is a common condition which affects a large proportion of the population, resulting in social, emotional and psychological stress. Certain oral bacteria form a coating called a biofilm on the tongue dorsum and degrade organic compounds releasing volatile sulfur compounds that are malodourous. Current chemical treatments for oral malodour such as mouthwashes containing chlorhexidine or essential oils, are not sufficiently effective at reducing the bacterial load on the tongue. One potential alternative to current chemical treatments for oral malodour is the use of light activated antimicrobial agents (LAAAs), which display no toxicity or antimicrobial activity in the dark, but when exposed to light of a specific wavelength produce reactive oxygen species which induce damage to target cells in a process known as photodynamic inactivation...
October 18, 2016: Journal of Breath Research
Valmiki B Koli, Sagar D Delekar, Shivaji H Pawar
In this study, nanocomposites of Fe-doped TiO2 with multi-walled carbon nanotubes (0.1- 0.5 wt. %) were prepared by using sol-gel method. The structural and morphological analysis were carried out with using X-ray diffraction pattern and transmission electron microscopy, which confirm the presence of pure anatase phase and particle sizes in the range 15-20 nm. X-ray photoelectron spectroscopy was used to determine the surface compositions of the nanocomposites. UV-vis diffuse reflectance spectra confirm redshift in the optical absorption edge of nanocomposites with increasing amount of multi-walled carbon nanotubes...
December 2016: Journal of Materials Science. Materials in Medicine
Xiayan Pan, Jian Wu, Shu Xu, Yabing Duan, Zhou Mingguo
Rice bacterial leaf blight, caused by Xanthomonas oryzae pv. oryzae (Xoo), and rice bacterial leaf streak, caused by Xanthomonas oryzae pv. oryzicola (Xoc), are major diseases of rice. Phenazine-1-carboxylic acid (PCA) is a natural product that is isolated from Pseudomonas spp. and is used to control many important rice diseases in China. We previously reported that PCA disturbs the redox balance, which results in the accumulation of reactive oxygen species (ROS) in Xoo. In this study, we found that PCA significantly up-regulated the transcript levels of catB and katE, which encode catalases, and that PCA-sensitivity was reduced when Xoo and Xoc were cultured with exogenous catalase...
October 17, 2016: Phytopathology
Xiaojia He, Donee' McAlliser, Winfred G Aker, Huey-Min Hwang
Titanium dioxide nanoparticles (TiO2 NPs) are among the most widely manufactured nanomaterials on a global scale. However, prudent and vigilant surveillance, incumbent upon the scientific community with the advent of new technologies, has revealed potentially undesirable effects of TiO2 NPs on biological systems and the natural environment during their application and discharge. Such effects are likely best evaluated by first assessing the fate of the TiO2 NPs in natural environments. In this study, the effects of terrestrial humic acid (HA) and tannic acid (TA), two major members of the collective: dissolved organic matter (DOM), on the cytotoxicity of TiO2 NPs to Escherichia coli were investigated in the presence and absence of natural sunlight...
October 2016: Journal of Environmental Sciences (China)
A Tassopoulos, A Chalkias, A Papalois, N Iacovidou, T Xanthos
The intestine is highly sensitive to ischemia/reperfusion (I/R) injury. Intestinal I/R may cause local tissue injury and disruption of the intestinal mucosal barrier, allowing the passage of viable bacteria and endotoxins from the gastrointestinal lumen to distant organs. This phenomenon, known as bacterial translocation (BT), may lead to systemic disorders with high morbidity and mortality. Oxidative stress mediators such as reactive oxygen species, polymorphonuclear neutrophils and nitric oxide are believed to contribute to the intestinal I/R injury...
October 13, 2016: Redox Report: Communications in Free Radical Research
Yu Hang Leung, Xiaoying Xu, Angel P Y Ma, Fangzhou Liu, Alan M C Ng, Zhiyong Shen, Lee A Gethings, Mu Yao Guo, Aleksandra B Djurišić, Patrick K H Lee, Hung Kay Lee, Wai Kin Chan, Frederick C C Leung
We performed a comprehensive investigation of the toxicity of ZnO and TiO2 nanoparticles using Escherichia coli as a model organism. Both materials are wide band gap n-type semiconductors and they can interact with lipopolysaccharide molecules present in the outer membrane of E. coli, as well as produce reactive oxygen species (ROS) under UV illumination. Despite the similarities in their properties, the response of the bacteria to the two nanomaterials was fundamentally different. When the ROS generation is observed, the toxicity of nanomaterial is commonly attributed to oxidative stress and cell membrane damage caused by lipid peroxidation...
October 12, 2016: Scientific Reports
Walid Mohamed, Eugen Domann, Trinad Chakraborty, Gopala Mannala, Katrin S Lips, Christian Heiss, Reinhard Schnettler, Volker Alt
BACKGROUND: Staphylococcus aureus is the principle causative pathogen of osteomyelitis and implant-associated bone infections. It is able to invade and to proliferate inside osteoblasts thus avoiding antibiotic therapy and the host immune system. Therefore, development of alternative approaches to stimulate host innate immune responses could be beneficial in prophylaxis against S. aureus infection. TLR9 is the intracellular receptor which recognizes unmethylated bacterial CpG-DNA and activates immune cells...
October 3, 2016: BMC Microbiology
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