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Waleed K Mohammed, Natalio Krasnogor, Nicholas S Jakubovics
The ability of microorganisms to regulate gene expression is thought to be critical for survival and growth during the development of polymicrobial biofilms such as dental plaque. The commensal dental plaque colonizer, Streptococcus gordonii, responds to cell-cell contact (coaggregation) with Actinomyces oris by regulating > 20 genes, including those involved in arginine biosynthesis. We hypothesized that an S. gordonii extracellular protease is critical for sensing by providing amino acids that modulate gene expression...
March 14, 2018: FEMS Microbiology Ecology
Qiushi Li, Jihui Wang, Xuteng Xing, Wenbin Hu
The corrosion behavior of X65 steel was investigated in the seawater inoculated with sulfate reducing bacteria (SRB) under the aerobic environment by electrochemical impedance techniques and immersion tests. The corroded morphologies and the composition of the corrosion products were investigated. The variation of the solution parameters including the bacterium number, the pH value and the soluble iron concentration were also investigated. The results indicated that in the SRB-containing system, the impedance responses presented a depressed semi-circle in the initial period, which then turned into the blocked electrode characteristic during the later immersion...
March 11, 2018: Bioelectrochemistry
Mohammad Sadekuzzaman, Md Furkanur Rahaman Mizan, Sungdae Yang, Hyung-Suk Kim, Sang-Do Ha
Microbial biofilms pose a serious threat to food industry, as they are difficult to inactivate or remove owing to their inherent resistance to traditional physical and antimicrobial treatments. Bacteriophages have been suggested as promising biocontrol agents for eliminating biofilms within the food industry. The efficacy of phages (BP 1369 and BP 1370) was evaluated against Salmonella spp. in biofilms. Biofilms were grown on food (lettuce), food contact surfaces (stainless steel and rubber), and MBEC biofilm devices...
January 1, 2018: Food Science and Technology International, Ciencia y Tecnología de Los Alimentos Internacional
José Andrés Medrano-Félix, Cristóbal Chaidez, Kristina D Mena, María Del Socorro Soto-Galindo, Nohelia Castro-Del Campo
Survival of bacterial pathogens in different environments is due, in part, to their ability to form biofilms. Four wild-type Salmonella enterica strains, two Oranienburg and two Saintpaul isolated from river water and animal feces, were tested for biofilm formation at the air-liquid interface under stressful conditions (pH and salinity treatments such as pH 3, NaCl 4.5 w/v; pH 7, NaCl 4.5 w/v; pH 10, NaCl 4.5 w/v; pH 3, Nacl 0.5 w/v; pH 7, NaCl 0.5 w/v; and pH 10, NaCl 0.5 w/v); Salmonella Typhimurium DT104 was used as a control strain...
March 15, 2018: Environmental Monitoring and Assessment
Louise Kruse Jensen, Nicole Lind Henriksen, Thomas Bjarnsholt, Kasper Nørskov Kragh, Henrik Elvang Jensen
Aim: Visualization of Staphylococcus aureus biofilm using histochemical staining and combined histochemistry (HC) and immunohistochemistry (IHC). Methods: The ability of S. aureus S54F9 to form biofilm was tested in vitro . Hereafter, infected bone tissue was collected from two different porcine models of osteomyelitis inoculated with S. aureus strain S54F9. The infection time was five and fifteen days, respectively. Twenty-five different histochemical staining protocols were tested in order to find the stains that could identify extracellular biofilm matrix...
2018: Journal of Bone and Joint Infection
Stefanie Amend, Roland Frankenberger, Susanne Lücker, Eugen Domann, Norbert Krämer
OBJECTIVES: The present study aimed to establish Lactobacillus casei in a completely automated Streptococcus mutans-based artificial mouth model and to investigate secondary caries inhibiting properties of glass ionomer cements / resin composite groups in vitro. METHODS: Sixty extracted, caries-free human third molars were used for preparation of standardized class-V-cavities. Specimens were restored with a resin-modified (Photac Fil; PF) as well as a conventional glass ionomer cement (Ketac Molar; KM) and one resin composite bonded with and without conduction of etch-and-rinse technique (Prime&Bond NT, Ceram X mono; C+ERT, C)...
March 12, 2018: Dental Materials: Official Publication of the Academy of Dental Materials
Komathy Munusamy, Jamuna Vadivelu, Sun Tee Tay
BACKGROUND: Biofilm is known to contribute to the antifungal resistance of Candida yeasts. Aureobasidin A (AbA), a cyclic depsipeptide targeting fungal sphingolipid biosynthesis, has been shown to be effective against several Candida species. AIMS: The aim of this study was to investigate Candida biofilm growth morphology, its biomass, metabolic activity, and to determine the effects of AbA on the biofilm growth. METHODS: The biofilm forming ability of several clinical isolates of different Candida species from our culture collection was determined using established methods (crystal violet and XTT assays)...
March 12, 2018: Revista Iberoamericana de Micología
Olivier Poupel, Caroline Proux, Bernd Jagla, Tarek Msadek, Sarah Dubrac
The success of Staphylococcus aureus, as both a human and animal pathogen, stems from its ability to rapidly adapt to a wide spectrum of environmental conditions. Two-component systems (TCSs) play a crucial role in this process. Here, we describe a novel staphylococcal virulence factor, SpdC, an Abi-domain protein, involved in signal sensing and/or transduction. We have uncovered a functional link between the WalKR essential TCS and the SpdC Abi membrane protein. Expression of spdC is positively regulated by the WalKR system and, in turn, SpdC negatively controls WalKR regulon genes, effectively constituting a negative feedback loop...
March 2018: PLoS Pathogens
Quintin Borgersen, David T Bolick, Glynis L Kolling, Matthew Aijuka, Fernando Ruiz-Perez, Richard L Guerrant, James P Nataro, Araceli E Santiago
Enteroaggregative E. coli (EAEC) is associated with food-borne outbreaks of diarrhea and growth faltering among children in developing countries. A Shiga toxin-producing EAEC strain of serotype O104:H4 strain caused one of the largest outbreaks of a food-borne infection in Europe in 2011. The outbreak was traced to contaminated fenugreek sprouts, yet the mechanisms whereby such persistent contamination of sprouts could have occurred are not clear. We found that under ambient conditions of temperature and in minimal media, pathogenic Shiga toxin-producing EAEC O104:H4 227-11 and non-Shiga toxin-producing 042 strains both produce high levels of exopolysaccharide structures (EPS) that are released to the external milieu...
March 15, 2018: Gut Microbes
Rajendra H Patil, Firoz A Kalam Khan, Kaivalya Jadhav, Manoj Damale, Siddique Akber Ansari, Hamad M Alkahtani, Azmat Ali Khan, Shantanu D Shinde, Rajesh Patil, Jaiprakash N Sangshetti
We report the synthesis of some new piperazine-sulphonamide linked Schiff bases as fungal biofilm inhibitors with antibacterial and antifungal potential. The biofilm inhibition result of Candida albicans proposed that the compounds 6b (IC50  = 32.1 μM) and 6j (IC50  = 31.4 μM) showed higher inhibitory activity than the standard fluconazole (IC50  = 40 μM). Compound 6d (MIC = 26.1 μg/mL) with a chloro group at the para position was found to be the most active antibacterial agent of the series against Bacillus subtilis when compared with the standard ciprofloxacin (MIC = 50 μg/mL)...
March 15, 2018: Archiv der Pharmazie
Neerupma Bhardwaj, Kirtimaan Syal, Dipankar Chatterji
ppGpp, an alarmone for stringent response, plays an important role in the reprogramming of the transcription complex at the time of stress. In Escherichia coli, ppGpp mediates its action by binding to at least two different sites on RNA polymerase (RNAP). One of the sites to which ppGpp binds to RNAP is at the β'-ω interface; however, the underlying molecular mechanism and the physiological relevance of ppGpp binding to this site remain unclear. In this study, we have performed UV cross-linking experiments using32 P azido-labeled ppGpp to probe its association with RNAP in the absence and presence of ω, and observed weaker binding of ppGpp to the RNAP without ω...
March 15, 2018: Genes to Cells: Devoted to Molecular & Cellular Mechanisms
Brijesh Kumar, John L Sorensen, Silvia T Cardona
Burkholderia cenocepacia is an opportunistic bacterium that can thrive in different environments, including the amino acid-rich mucus of the cystic fibrosis (CF) lung. B. cenocepacia responds to the nutritional conditions that mimic the CF sputum by increasing flagellin expression and swimming motility. Individual amino acids also induce swimming but not flagellin expression. Here, we show that modulation of the second messenger cyclic dimeric guanosine monophosphate (c-di-GMP) levels by the PAS-containing c-di-GMP phosphodiesterase, BCAL1069 (CdpA), regulates the swimming motility of B...
2018: Frontiers in Cellular and Infection Microbiology
Katherine Y Le, Matthew D Park, Michael Otto
The primary virulence factor of the skin commensal and opportunistic pathogen, Staphylococcus epidermidis , is the ability to form biofilms on surfaces of implanted materials. Much of this microorganism's pathogenic success has been attributed to its ability to evade the innate immune system. The primary defense against S. epidermidis biofilm infection consists of complement activation, recruitment and subsequent killing of the pathogen by effector cells. Among pathogen-derived factors, the biofilm exopolysaccharide polysaccharide intercellular adhesion (PIA), as well as the accumulation-associated protein (Aap), and the extracellular matrix binding protein (Embp) have been shown to modulate effector cell-mediated killing of S...
2018: Frontiers in Microbiology
Leron Khalifa, Daniel Gelman, Mor Shlezinger, Axel Lionel Dessal, Shunit Coppenhagen-Glazer, Nurit Beyth, Ronen Hazan
The deteriorating effectiveness of antibiotics is propelling researchers worldwide towards alternative techniques such as phage therapy: curing infectious diseases using viruses of bacteria called bacteriophages. In a previous paper, we isolated phage EFDG1, highly effective against both planktonic and biofilm cultures of one of the most challenging pathogenic species, the vancomycin-resistant Enterococcus (VRE). Thus, it is a promising phage to be used in phage therapy. Further experimentation revealed the emergence of a mutant resistant to EFDG1 phage: EFDG1r ...
2018: Frontiers in Microbiology
Qian Liu, Yang Yang, Xiaoxue Mei, Bingfeng Liu, Chuan Chen, Defeng Xing
Ferric iron can affect the current generation of microbial electrochemical system (MES); however, how it influences microbial biofilm formation and metabolic activity has not been reported. Here, we describe the response of microbial electrode biofilm communities to insoluble ferric iron (Fe3+ ) at different concentrations in microbial fuel cells (MFCs). Insoluble ferric iron (200μM) improved electrochemical activity of the MFCs microbial biofilms during start-up and resulted in a higher maximum power density of 0...
March 11, 2018: Science of the Total Environment
Hui Sun, Yuanxiu Hong, Yuejing Xi, Yijie Zou, Jingyi Gao, Jianzhong Du
Antimicrobial peptides (AMPs) have been attracting much attention due to their excellent antimicrobial efficiency and low rate in driving antimicrobial resistance (AMR) which has been increasing globally to alarming levels. Conjugation of AMPs into functional polymers not only preserves excellent antimicrobial activities but reduces the toxicity and offers more functionalities, which brings new insight towards developing multifunctional biomedical materials such as hydrogels, polymer vesicles, polymer micelles, etc...
March 14, 2018: Biomacromolecules
Noreen J Hickok
No abstract text is available yet for this article.
April 1, 2018: Spine
Raza Aly, Tate Winter, Steve Hall, Tracey Vlahovic
Dermatophytoma is a little-known, difficult to treat fungal infection that complicates onychomycosis. First described by Roberts and Evans in the late 1990's, dermatophytoma presents as a dense concentration of fungal hyphae within or under the nail plate and is generally white or yellow/brown in color, and linear (streaks) or round (patches) in shape; primary etiologic organisms are dermatophytes. Oral antifungals have limited success in treating dermatophytoma owing to difficulties accessing and penetrating what is hypothesized to be a fungal biofilm...
March 1, 2018: Journal of Drugs in Dermatology: JDD
Ripon Sarkar, Aritri Ghosh, Ananya Barui, Pallab Datta
Topical application of honey for tissue regeneration, has recently regained attention in clinical practice with controlled studies affirming its efficacy and indicating its role in regeneration over repair. Parallely, to overcome difficulties of applying raw honey, several product development studies like nanofibrous matrices have been reported. However, one approach concentrated on achieving highest possible honey loading in the nanofiber membranes while other studies have found that only specific honey dilutions result in differential cellular responses on wound healing and re-epithelization...
March 13, 2018: Journal of Materials Science. Materials in Medicine
Roberto Scaffaro, Francesco Lopresti, Manuela D'Arrigo, Andreana Marino, Antonia Nostro
Carvacrol (CAR) is one of the most promising essential oil components with antimicrobial activity. New technologies aimed to incorporate this active molecule into carrier matrix to improve the stability and prolong the biological activity. The goal of this study was to investigate the feasibility of incorporating CAR into electrospun membranes of poly(lactic acid) (PLA) for potential applications as active antimicrobial system. To this end, PLA membranes containing homogeneously dispersed CAR were successfully prepared and a series of systematic tests including morpho-mechanical properties, in vitro release rate, and antimicrobial/antibiofilm activities against Staphylococcus aureus and Candida albicans were carried out...
March 13, 2018: Applied Microbiology and Biotechnology
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