Read by QxMD icon Read


Xiaolong Shao, Xiaoning Zhang, Yingchao Zhang, Miao Zhu, Pan Yang, Jian Yuan, Yingpeng Xie, Tianhong Zhou, Wei Wang, Sheng Chen, Haihua Liang, Xin Deng
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen of humans, particularly those with cystic fibrosis. As a global regulator, RpoN controls a group of virulence-related factors and quorum sensing (QS) genes in P. aeruginosa To further gain insights into the direct targets of RpoN in vivo , the present study focused on identifying the direct targets of RpoN regulation in QS and the type VI secretion system (T6SS). We performed a chromatin immunoprecipitation coupled to high-throughput sequencing (ChIP-seq) assay that identified 1,068 binding sites of RpoN, mostly including metabolic genes, a group of genes in QS ( lasI , rhlI and pqsR ) and the T6SS ( hcpA and hcpB )...
May 14, 2018: Journal of Bacteriology
Michael Muller
Silver has emerged as an important therapeutic option for wound infections in recent years due to its broad spectrum antimicrobial activity. The silver cation (Ag+ ), but not the bulk metal (Ag0 ), is highly toxic for most microorganisms although resistance due to genetic modification or horizontal gene transfer does occur. Pseudomonas aeruginosa , however, achieves silver resistance by producing the redox active metabolite pyocyanin that reduces Ag+ to non-toxic Ag0 Pyocyanin also possess broad spectrum antimicrobial activity...
May 14, 2018: Antimicrobial Agents and Chemotherapy
Jiajia You, Li Sun, Xiaojing Yang, Xuewei Pan, Zhiwei Huang, Xixi Zhang, Mengxin Gong, Zheng Fan, Lingyan Li, Xiaoli Cui, Zhaoyuan Jing, Shouguang Jin, Zhiming Rao, Weihui Wu, Hongjiang Yang
Our understanding of the molecular mechanisms behind bacteria-phage interactions remains limited. Here we report that a small protein, SrpA, controls core cellular processes in response to phage infection and environmental signals in Pseudomonas aeruginosa. We show that SrpA is essential for efficient genome replication of phage K5, and controls transcription by binding to a palindromic sequence upstream of the phage RNA polymerase gene. We identify potential SrpA-binding sites in 66 promoter regions across the P...
May 10, 2018: Nature Communications
Subhaswaraj Pattnaik, Tanveer Ahmed, Sampath Kumar Ranganathan, Dinakara Rao Ampasala, V Venkateswara Sarma, Siddharha Busi
Pseudomonas aeruginosa is an opportunistic nosocomial pathogen causing the majority of acute and persistent infections in human beings. The ability to form biofilm adds a new dimension to its resistance to conventional therapeutic agents. In the present study, down-regulation of quorum sensing regulated virulence and biofilm development resulting from exposure to Aspergillus ochraceopetaliformis SSP13 extract was investigated. The in vitro results inferred impairment in the production of LasA protease, LasB elastase, chitinase, pyocyanin, exopolysaccharides and rhamnolipids...
May 10, 2018: Biofouling
Ivana Aleksic, Petar Ristivojevic, Aleksandar Pavic, Ivana Radojević, Ljiljana R Čomić, Branka Vasiljevic, Dejan Opsenica, Dušanka Milojković-Opsenica, Lidija Senerovic
ETHNOPHARMACOLOGICAL RELEVANCE: Trapa natans L. (water chestnut or water caltrop) is a widespread aquatic plant, which has been cultivated for food and traditional medicine since ancient times. Pharmacological studies showed that water chestnut exhibits the wide range of biological activities, such as antimicrobial, antioxidative, analgesic, anti-inflammatory, as well as antiulcer. AIMOF THE STUDY: Evaluation of anti-virulence potential and toxicity of T. natans methanol (TnM), acetone (TnA) and ethyl acetate (TnEA) leaf extracts...
May 4, 2018: Journal of Ethnopharmacology
Nina Jagmann, Bodo Philipp
The opportunistic pathogen Pseudomonas aeruginosa employs its complex quorum sensing (QS) network to regulate the expression of virulence factors such as pyocyanin. Besides cell density, QS in this bacterium is co-regulated by environmental cues. In this study, we employed a previously established co-culture model system to identify metabolic influences that are involved in the regulation of pyocyanin production in P. aeruginosa . In this co-culture consisting of P. aeruginosa and the chitinolytic bacterium Aeromonas hydrophila , parasitic growth of P...
2018: Frontiers in Microbiology
Hongyun Nie, Maiqian Nie, Lei Wang, Zhenjun Diwu, Ting Xiao, Qi Qiao, Yan Wang, Xin Jiang
The aim of this work was to investigate the effects of secreted extracellular phenazine compounds (PHCs) on the degradation efficiency of alkanes by P. aeruginosa NY3. Under aerobic conditions, the PHCs secreted by P. aeruginosa NY3 initiate the oxidation of alkanes outside cells, in coupling with some reducing agents, such as β-Nicotinamide adenine dinucleotide, reduced disodium salt (NADH) or reduced glutathione (GSH). This reaction might be via free radical reactions similar to Fenton Oxidation Reaction (FOR)...
March 2, 2018: Water Research
Demet Hançer Aydemir, Gülşah Çifçi, Viktorya Aviyente, Gülgün Boşgelmez-Tinaz
AIMS: Quorum sensing (QS) is a cell-cell communication system used by a broad spectrum of pathogenic bacteria to control the expression of their virulence genes. The interruption of QS systems of pathogenic bacteria has been considered as a novel way to fight bacterial diseases. In this study, trans-anethole, the main component of anise (Pimpinella anisum) oil was examined for its QS inhibitor (QSI) potential in an attempt to identify novel QSI compound effective against opportunistic pathogen P...
April 25, 2018: Journal of Applied Microbiology
Yee Meng Chong, Kah Yan How, Wai Fong Yin, Kok Gan Chan
The quorum sensing (QS) system has been used by many opportunistic pathogenic bacteria to coordinate their virulence determinants in relation to cell-population density. As antibiotic-resistant bacteria are on the rise, interference with QS has been regarded as a novel way to control bacterial infections. As such, many plant-based natural products have been widely explored for their therapeutic roles. These natural products may contain anti-QS compounds that could block QS signals generation or transmission to combat QS pathogens...
April 21, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Dusan Milivojevic, Neven Šumonja, Strahinja Medic, Aleksandar Pavic, Ivana Moric, Branka Vasiljevic, Lidija Senerovic, Jasmina Nikodinovic-Runic
Pseudomonas aeruginosa, has been amongst top 10 'superbugs' worldwide and is causing infections with poor outcomes in both humans and animals. From 202 P. aeruginosa isolates (n = 121 animal and n = 81 human) 40 were selected on the basis of biofilm-forming ability and were comparatively characterized in terms of virulence determinants to the type strain P. aeruginosa PAO1. Biofilm formation, pyocyanin and hemolysins production and bacterial motility patterns were compared to the ability to kill human cell line A549 in vitro...
April 19, 2018: Pathogens and Disease
Tricia A Van Laar, Saika Esani, Tyler J Birges, Bethany Hazen, Jason M Thomas, Mamta Rawat
Pseudomonas aeruginosa is a ubiquitous Gram-negative bacterium that can cause severe opportunistic infections. The principal redox buffer employed by this organism is glutathione (GSH). To assess the role of GSH in the virulence of P. aeruginosa , a number of analyses were performed using a mutant strain deficient in gshA , which does not produce GSH. The mutant strain exhibited a growth delay in minimal medium compared to the wild-type strain. Furthermore, the gshA mutant was defective in biofilm and persister cell formation and in swimming and swarming motility and produced reduced levels of pyocyanin, a key virulence factor...
April 25, 2018: MSphere
Richard D Waite, Joanne E Stewart, Abish S Stephen, Robert P Allaker
Wound bioburden plays an important role in impaired healing and the development of infection-related complications. The objective of this study was to determine the efficacy of an innovative two-layer nitric oxide generating system (NOx) to prevent and treat biofilms formed by bacterial and fungal pathogens commonly associated with wound infection, and activity against Pseudomonas aeruginosa virulence factors. Single and mixed species biofilms were grown for 24h on nitrocellulose filters placed on agar. Filters were covered with either NOx or placebo, before and after biofilm formation...
April 14, 2018: International Journal of Antimicrobial Agents
Weiwei Dong, Jie Zhu, Xiang Guo, Delong Kong, Qi Zhang, Yiqing Zhou, Xiaoyang Liu, Shumiao Zhao, Zhiyong Ruan
N-Acyl homoserine lactones (AHLs) act as the key quorum sensing (QS) signal molecules in gram-negative bacteria, which coordinates gene expression and then activates various processes, including biofilm formation and production of virulence factors in some pathogens. Quorum quenching (QQ), which is the inactivation of the signal molecules by means of enzymatic degradation or modification, inhibits the processes of QS rather than killing the pathogens and is a promising antipathogenic strategy to control the bacterial pathogens...
April 16, 2018: Scientific Reports
Joann Phan, Tara Gallagher, Andrew Oliver, Whitney England, Katrine Whiteson
Pseudomonas aeruginosa is a well-known dominant opportunistic pathogen in cystic fibrosis (CF) with a wide range of metabolic capacities. However, P. aeruginosa does not colonize the airways alone, and benefits from the metabolic products of neighboring cells-especially volatile molecules that can travel between different parts of the airways easily. Here, we present a study that investigates the metabolic, gene expression profiles, and phenotypic responses of a P. aeruginosa clinical isolate to fermentation products lactic acid and 2,3-butanediol, metabolites that are produced by facultative anaerobic members of the CF polymicrobial community and potential biomarkers of disease progression...
March 29, 2018: FEMS Microbiology Letters
Jin-Hyung Lee, Yong-Guy Kim, Jintae Lee
Pseudomonas aeruginosa biofilms are problematic and play a critical role in the persistence of chronic infections because of their ability to tolerate antimicrobial agents. In this study, various cell-wall degrading enzymes were investigated for their ability to inhibit biofilm formation of two P. aeruginosa strains, PAO1 and PA14. Xylanase markedly inhibited and detached P. aeruginosa biofilms without affecting planktonic growth. Xylanase treatment broke down extracellular polymeric substances and decreased the viscosity of P...
April 4, 2018: Biofouling
Huiming Tang, Yunyun Zhang, Yifan Ma, Mengmeng Tang, Dongsheng Shen, Meizhen Wang
Quorum sensing (QS) regulates the behavior of bacterial populations and promotes their adaptation and survival under stress. As QS is responsible for the virulence of vast majority of bacteria, quorum quenching (QQ), the interruption of QS, has become an attractive therapeutic strategy. However, the role of QS in stress tolerance and the efficiency of QQ under stress in bacteria are seldom explored. In this study, we demonstrated that QS-regulated catalase (CAT) expression and biofilm formation help Pseudomonas aeruginosa PAO1 resist nicotine stress...
2018: Frontiers in Cellular and Infection Microbiology
Jian Lin Li, Ningjing Yang, Lei Huang, Dandan Chen, Yu Zhao, M Matt Tang, Huizhou Fan, Xiaofeng Bao
The obligate intracellular bacterium Chlamydia is a widespread human pathogen that causes serious problems including (but not limited to) infertility and blindness. Our search for novel antichlamydial metabolites from marine-derived microorganisms led to isolation of pyocyanin, a small compound from Pseudomonas aeruginosa Pyocyanin is an effective antichlamydial for all three Chlamydia spp. tested. It has an IC50 of 0.019 ∼ 0.028 μM, which is comparable to the IC50 of tetracycline. At concentrations as low as 0...
April 2, 2018: Antimicrobial Agents and Chemotherapy
Hoang D Lu, Elizabeth Pearson, Kurt D Ristroph, Gregg A Duncan, Laura M Ensign, Jung Soo Suk, Justin Hanes, Robert K Prud'homme
Pseudomonas aeruginosa is an opportunistic gram-negative pathogen that causes a wide range of infections; it is becoming increasingly difficult to treat due to antibiotic resistance. Quorum-sensing (QS) based therapeutics, which function by disabling pathogen virulence without killing pathogens, are a promising class of drugs that may be used to treat bacterial infections without eliciting resistance development. The use of QS drugs to treat pulmonary P. aeruginosa infections, however, has been greatly limited due to the inability to deliver QS drugs at sufficiently high concentrations past physiological barriers such as pulmonary mucus...
March 30, 2018: International Journal of Pharmaceutics
Luana da S M Forezi, Thamires Quadros Froes, Mariana F C Cardoso, Carine Assuncao de Oliveira Maciel, Gianluca G Nicastro, Regina L Baldini, Dora C S Costa, Vitor F Ferreira, Marcelo S Castilho, Fernando de C da Silva
Antimicrobial resistance (AMR) is a serious problem for the humans since it threatens the effective prevention and treatment of an ever-increasing range of infections caused by bacteria, parasites, viruses and fungi. One way around this problem is to act on the virulence factors, produced by bacteria, which increase their infection effectiveness. In view of these facts, new coumarin derivatives were synthesized and evaluated for their anti-virulence biological activity towards Pseudomonas aeruginosa. The results suggest that coumarin derivatives with a secondary carbon at C-3 position reduces P...
March 29, 2018: Current Topics in Medicinal Chemistry
Cuong Quoc Nguyen, William John Thrift, Arunima Bhattacharjee, Saba Ranjbar, Tara Gallagher, Mahsa Darvishzadeh-Varcheie, Robert Noboru Sanderson, Filippo Capolino, Katrine Whiteson, Pierre Baldi, Allon I Hochbaum, Regina Ragan
Detection of bacterial metabolites at low concentrations in fluids with complex background allows for applications ranging from detecting biomarkers of respiratory infections to identifying contaminated medical instruments. Surface enhanced Raman scattering (SERS) spectroscopy, when utilizing plasmonic nanogaps, has the relatively unique capacity to reach trace molecular detection limits in a label free format, yet large-area device fabrication incorporating nanogaps with this level of performance has proven difficult...
March 28, 2018: ACS Applied Materials & Interfaces
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"