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virulence genes and biofilm formation

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https://www.readbyqxmd.com/read/29133345/small-rna-teg49-is-derived-from-a-sara-transcript-and-regulates-virulence-genes-independent-of-sara-in-staphylococcus-aureus
#1
Adhar C Manna, Samin Kim, Liviu Cengher, Anna Corvaglia, Stefano Leo, Patrice Francois, Ambrose L Cheung
Expression of virulence factors in S. aureus is regulated by a wide range of transcriptional regulators including proteins and small RNAs (sRNAs) at the level of transcription and/or translation. The sarA locus consists of three overlapping transcripts generated from three distinct promoters, all encoding the sarA ORF. The 5' UTRs of these transcripts contain three separate regions at ∼711, 409, and 146-nt upstream of the sarA translation start, the functions of which remain unknown. Recent RNA-Seq analysis and subsequent characterization indicated that two sRNA, teg49 and teg48, are processed and likely produced from the sarA P3 and sarA P1 transcripts of the sarA locus, respectively...
November 13, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/29130172/enzymatic-assays-to-investigate-acyl-homoserine-lactone-autoinducer-synthases
#2
Daniel Shin, Rajesh Nagarajan
Bacteria use chemical molecules called autoinducers as votes to poll their numerical strength in a colony. This polling mechanism, commonly referred to as quorum sensing, enables bacteria to build a social network and provide a collective response for fighting off common threats. In Gram-negative bacteria, AHL synthases synthesize acyl-homoserine lactone (AHL) autoinducers to turn on the expression of several virulent genes including biofilm formation, protease secretion, and toxin production. Therefore, inhibiting AHL signal synthase would limit quorum sensing and virulence...
2018: Methods in Molecular Biology
https://www.readbyqxmd.com/read/29130160/use-of-whole-cell-bioassays-for-screening-quorum-signaling-quorum-interference-and-biofilm-dispersion
#3
Starla G Thornhill, Robert J C McLean
In most bacteria, a global level of regulation, termed quorum sensing (QS), exists involving intercellular communication via the production and response to cell density-dependent signal molecules. QS has been associated with a number of important features in bacteria including virulence regulation and biofilm formation. Consequently, there is considerable interest in understanding, detecting, and inhibiting QS. N-acylated homoserine lactones (AHLs) are used as extracellular QS signals by a variety of Gram-negative bacteria...
2018: Methods in Molecular Biology
https://www.readbyqxmd.com/read/29114981/ptab-a-lim-domain-binding-protein-in-aspergillus-fumigatus-regulates-biofilm-formation-and-conidiation-through-distinct-pathways
#4
Shizhu Zhang, Yuan Chen, Zhihua Ma, Qiuyi Chen, Hanna Ostapska, Fabrice N Gravelat, Ling Lu, Donald C Sheppard
The exopolysaccharide galactosaminogalactan (GAG) plays an important role in mediating adhesion, biofilm formation and virulence in the pathogenic fungus Aspergillus fumigatus. The developmental modifiers MedA, StuA and SomA regulate GAG biosynthesis, but the mechanisms underlying this regulation are poorly understood. PtaB is a lim-domain binding protein that interacts with the transcription factor SomA and is required for normal conidiation and biofilm formation. Disruption of ptaB resulted in impaired GAG production and conidiation in association with a markedly reduced expression of GAG biosynthetic genes (uge3 and agd3), developmental regulators (medA and stuA), and genes involved in the core conidiation pathway...
November 7, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29112725/peptide-transporter-yjiy-influences-the-expression-of-the-virulence-gene-mgtc-to-regulate-biofilm-formation-in-salmonella
#5
Preeti Garai, Kasturi Chandra, Jayanta Chatterjee, Dipshikha Chakravortty
Biofilm is one of the coping strategies of Salmonella against antimicrobial environmental stresses including nutrient starvation. However, channeling of the cue of starvation towards biofilm formation is not understood well. Our study shows that a carbon starvation gene, yjiY, coding for a peptide transporter, influences the expression of a virulence associated gene, mgtC, in Salmonella, to regulate biofilm formation. We demonstrate here that the mutant strain, ΔyjiY, is unable to form biofilm due to the increased expression of mgtC...
November 3, 2017: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/29111323/the-role-of-the-ptsi-gene-on-ai-2-internalization-and-pathogenesis-of-avian-pathogenic-escherichia-coli
#6
Xiaoka Wu, Xiaolong Lv, Jinye Lu, Shengqing Yu, Yawei Jin, Jiangang Hu, Jiakun Zuo, Rongsheng Mi, Yan Huang, Kezong Qi, Zhaoguo Chen, Xiangan Han
The LuxS/AI-2 quorum sensing mechanism can regulate the physiological functions of avian pathogenic Escherichia coli (APEC) through internalization of the small molecule autoinducer-2 (AI-2). The ptsI gene encodes enzyme I, which participates in the phosphotransferase system (PTS) that regulates the virulence and AI-2 internalization of bacteria. The aim of the present study was to determine the effect of ptsI on AI-2 internalization and other pathogenesis process in APEC using a ptsI mutant of the APEC strain DE17 (serotype O2), namely DE17ΔptsI...
October 27, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/29106298/phenotypic-and-molecular-characterization-of-salmonella-enteritidis-se86-isolated-from-poultry-and-salmonellosis-outbreaks
#7
Karen Apellanis Borges, Thales Quedi Furian, Sara Neves de Souza, Rafaela Menezes, Carlos Tadeu Pippi Salle, Hamilton Luiz de Souza Moraes, Eduardo César Tondo, Vladimir Pinheiro do Nascimento
Salmonella Enteritidis remains a standout among the leading causes of foodborne diseases worldwide. Previous studies have demonstrated that a unique clonal group of Salmonella Enteritidis, named SE86, is involved in foodborne outbreaks in southern Brazil and is frequently identified among strains isolated from poultry. The aim of this study was to determine the influence of the isolation source (food products involved in salmonellosis outbreaks and poultry sources) on the phenotypic and molecular characteristics of Salmonella Enteritidis SE86...
November 6, 2017: Foodborne Pathogens and Disease
https://www.readbyqxmd.com/read/29101490/inhibition-of-quorum-sensing-dependent-biofilm-and-virulence-genes-expression-in-environmental-pathogen-serratia-marcescens-by-petroselinic-acid
#8
Srinivasan Ramanathan, Durgadevi Ravindran, Kannappan Arunachalam, Veera Ravi Arumugam
The aim of this study was to evaluate the anti-biofilm and anti-virulence properties of petroselinic acid (PSA) against the environmental pathogen Serratia marcescens. PSA significantly inhibited the quorum sensing (QS)-dependent virulence factors such as prodigiosin, protease productions, and biofilm formation in S. marcescens. The antibiofilm potential of PSA was also confirmed through light, confocal laser scanning, and scanning electron microscopic analyses. Furthermore, PSA effectively inhibited the biofilm-related phenomena such as exopolysaccharide production, hydrophobicity production, swimming, and swarming motility without affecting the bacterial growth...
November 3, 2017: Antonie Van Leeuwenhoek
https://www.readbyqxmd.com/read/29101062/antibacterial-and-antibiofilm-activities-of-eugenol-from-essential-oil-of-syzygium-aromaticum-l-merr-l-m-perry-clove-leaf-against-periodontal-pathogen-porphyromonas-gingivalis
#9
Yi Zhang, Yue Wang, Xiaojing Zhu, Ping Cao, Shaomin Wei, Yanhua Lu
The antibacterial effect and mechanism of eugenol from Syzygium aromaticum (L.) Merr. & L. M. Perry (clove) leaf essential oil (CLEO) against oral anaerobe Porphyromonas gingivalis were investigated. The results showed that eugenol, with content of 90.84% in CLEO, exhibited antibacterial activity against P. gingivalis at a concentration of 31.25 μM. Cell shrink and lysis caused by eugenol were observed with Scanning Electron Microscopy (SEM). The release of macromolecules and uptake of fluorescent dye indicated that the antibacterial activity was due to the ability of eugenol to permeabilize the cell membrane and destroy the integrity of plasmatic membrane irreversibly...
October 31, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/29090193/reduced-intracellular-c-di-gmp-content-increases-expression-of-quorum-sensing-regulated-genes-in-pseudomonas-aeruginosa
#10
Song Lin Chua, Yang Liu, Yingying Li, Hui Jun Ting, Gurjeet S Kohli, Zhao Cai, Pipob Suwanchaikasem, Kelvin Kau Kit Goh, Sean Pin Ng, Tim Tolker-Nielsen, Liang Yang, Michael Givskov
Cyclic-di-GMP (c-di-GMP) is an intracellular secondary messenger which controls the biofilm life cycle in many bacterial species. High intracellular c-di-GMP content enhances biofilm formation via the reduction of motility and production of biofilm matrix, while low c-di-GMP content in biofilm cells leads to increased motility and biofilm dispersal. While the effect of high c-di-GMP levels on bacterial lifestyles is well studied, the physiology of cells at low c-di-GMP levels remains unclear. Here, we showed that Pseudomonas aeruginosa cells with high and low intracellular c-di-GMP contents possessed distinct transcriptome profiles...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/29081982/the-making-of-a-miscreant-tobacco-smoke-and-the-creation-of-pathogen-rich-biofilms
#11
Samir A Shah, Sukirth M Ganesan, Saradhadevi Varadharaj, Shareef M Dabdoub, John D Walters, Purnima S Kumar
We have previously reported that oral biofilms in clinically healthy smokers are pathogen-rich, and that this enrichment occurs within 24 h of biofilm formation. The present investigation aimed to identify a mechanism by which smoking creates this altered community structure. By combining in vitro microbial-mucosal interface models of commensal (consisting of Streptococcus oralis, Streptococcus sanguis, Streptococcus mitis, Actinomyces naeslundii, Neisseria mucosa and Veillonella parvula) and pathogen-rich (comprising S...
2017: NPJ Biofilms and Microbiomes
https://www.readbyqxmd.com/read/29067011/aii810-a-novel-cold-adapted-n-acylhomoserine-lactonase-discovered-in-a-metagenome-can-strongly-attenuate-pseudomonas-aeruginosa-virulence-factors-and-biofilm-formation
#12
Xinjiong Fan, Mingjun Liang, Lei Wang, Ruo Chen, He Li, Xiaolong Liu
The pathogen Pseudomonas aeruginosa uses quorum sensing (QS) to control virulence and biofilm formation. Enzymatic disruption of quorum sensing is a promising anti-infection therapeutic strategy that does not rely on antibiotics. Here, a novel gene (aii810) encoding an N-acylhomoserine lactonase was isolated from the Mao-tofu metagenome for the first time. Aii810 encoded a protein of 269 amino acids and was expressed in Escherichia coli BL21 (DE3) in soluble form. It showed the highest activity at 20°C, and it maintained 76...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29063141/cmpx-affects-virulence-in-pseudomonas-aeruginosa-through-the-gac-rsm-signaling-pathway-and-by-modulating-c-di-gmp-levels
#13
Anjali Y Bhagirath, Deepti Somayajula, Yanqi Li, Kangmin Duan
Pseudomonas aeruginosa is an ubiquitous organism which is able to infect and colonize many types of hosts including humans. Colonization of P. aeruginosa in chronic infections leads to the formation of biofilms, which are difficult to eradicate. P. aeruginosa is capable of regulating its virulence factors in response to external environment triggers and its signaling mechanism involves two-component regulatory systems and small molecules such as bis-(3'-5')-cyclic dimeric guanosine monophosphate. PA1611-RetS-GacS/A-RsmA/Y/Z is a key regulatory pathway in P...
October 23, 2017: Journal of Membrane Biology
https://www.readbyqxmd.com/read/29056046/synthesis-of-all-possible-canonical-3-5-linked-cyclic-dinucleotides-and-evaluation-of-riboswitch-interactions-and-immune-stimulatory-effects
#14
Changhao Wang, Malte Sinn, Julia Stifel, Anna C Heiler, Annette Sommershof, Jörg S Hartig
The cyclic dinucleotides (CDNs) c-di-GMP, c-di-AMP, and c-AMP-GMP are widely utilized as second messengers in bacteria, where they signal lifestyle changes such as motility and biofilm formation, cell wall and membrane homeostasis, virulence, and exo-electrogenesis. For all known bacterial CDNs, specific riboswitches have been identified that alter gene expression in response to the second messengers. In addition, bacterial CDNs trigger potent immune responses, making them attractive as adjuvants in immune therapies...
November 2, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29053421/development-of-a-novel-herbal-formulation-to-inhibit-biofilm-formation-in-toxigenic-vibrio-cholerae
#15
Diana Jose, N Lekshmi, A K Goel, R Ajay Kumar, Sabu Thomas
Vibrio cholerae, a causative agent of the waterborne disease cholera, still threatens a large proportion of world's population. The role of biofilm formation in V. cholerae pathogenesis is well established, as it provides the bacterium enhanced tolerance to antimicrobial agents and increased transmission. In the present study, four medicinal plants used in traditional medicines with antidiarrheal properties were evaluated for its antibiofilm activity. Methanol extracts of these plants (Centella asiatica, Elephantopus scaber, Camellia sinensis, and Holarrhena antidysenterica) showed promising antibiofilm activity against V...
October 20, 2017: Journal of Food Protection
https://www.readbyqxmd.com/read/29050256/in-vitro-and-in-vivo-effects-of-suloctidil-on-growth-and-biofilm-formation-of-the-opportunistic-fungus-candida-albicans
#16
Beini Zeng, Jiachen Li, Yajie Wang, Pengxiang Chen, Xiaohong Wang, Jianfeng Cui, Lidong Liu, Xiaoyan Hu, Qian Cao, Ying Xiao, Junlu Dong, Yundong Sun, Yabin Zhou
As the most frequent fungal pathogen in humans, Candida albicans can develop serious drug resistance because its biofilms are resistant to most antifungal agents; this leads to an urgent need to develop novel antifungals. Here, we evaluated the efficacy of an antithrombotic drug, suloctidil, against C. albicans biofilms in vitro and in vivo. We found that suloctidil is effective to inhibit C. albicans biofilm, with a minimum inhibitory concentration (MIC80) of 4 μg/mL, a biofilm inhibiting concentration (BIC80) of 16 μg/mL and a biofilm eradicating concentration (BEC80) of 64 μg/mL...
September 19, 2017: Oncotarget
https://www.readbyqxmd.com/read/29049010/biofilm-related-diseases-and-omics-global-transcriptional-profiling-of-enterococcus-faecium-reveals-different-gene-expression-patterns-in-the-biofilm-and-planktonic-cells
#17
Shu Yong Lim, Cindy Shuan Ju Teh, Kwai Lin Thong
Enterococcus faecium is an opportunistic pathogen with a remarkable ability to acquire resistance toward multiple antibiotics, including those of last-resort drugs such as vancomycin and daptomycin. The occurrence of vancomycin-resistant E. faecium is on the rise and there is a need to understand the virulence of this organism. One of the factors that contributes to the virulence is the ability to form biofilms. Since bacteria in biofilm state are more resistant to antibiotics and host immune response, understanding the molecular mechanism of biofilm development is important to control biofilm-related diseases...
October 2017: Omics: a Journal of Integrative Biology
https://www.readbyqxmd.com/read/29047237/proteus-vulgaris-and-proteus-mirabilis-decrease-candida-albicans-biofilm-formation-by-suppressing-morphological-transition-to-its-hyphal-form
#18
Kyoung Ho Lee, Su Jung Park, Sun Ju Choi, Joo Young Park
PURPOSE: Candida albicans (C. albicans) and Proteus species are causative agents in a variety of opportunistic nosocomial infections, and their ability to form biofilms is known to be a virulence factor. In this study, the influence of co-cultivation with Proteus vulgaris (P. vulgaris) and Proteus mirabilis (P. mirabilis) on C. albicans biofilm formation and its underlying mechanisms were examined. MATERIALS AND METHODS: XTT reduction assays were adopted to measure biofilm formation, and viable colony counts were performed to quantify yeast growth...
November 2017: Yonsei Medical Journal
https://www.readbyqxmd.com/read/29042302/attenuation-of-pseudomonas-aeruginosa-quorum-sensing-virulence-and-biofilm-formation-by-extracts-of-andrographis-paniculata
#19
Malabika Banerjee, Soumitra Moulick, Kunal Kumar Bhattacharya, Debaprasad Parai, Subrata Chattopadhyay, Samir Kumar Mukherjee
Quorum-sensing (QS) is known to play an essential role in regulation of virulence factors and toxins during Pseudomonas aeruginosa infection which may frequently cause antibiotic resistance and hostile outcomes of inflammatory injury. Therefore, it is an urgent need to search for a novel agent with low risk of resistance development that can target QS and inflammatory damage prevention as well. Andrographis paniculata, a herbaceous plant under the family Acanthaceae, native to Asian countries and also cultivated in Scandinavia and some parts of Europe, has a strong traditional usage with its known antibacterial, anti-inflammatory, antipyretic, antiviral and antioxidant properties...
October 14, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/29040072/enterococci-populations-of-a-metropolitan-river-after-an-extreme-flood-event-prevalence-persistence-and-virulence-determinants
#20
Nicole M Masters, Aaron Wiegand, Jasmin M Thompson, Tara L Vollmerhausen, Eva Hatje, Mohammad Katouli
We investigated the prevalence, persistence and virulence determinants of enterococci populations in water samples collected over three rounds following an extreme flood event in a metropolitan river. Enterococci (n = 482) were typed using the high resolution biochemical fingerprinting method (PhP typing) and grouped into common (C) or single (S) biochemical phenotypes (BPTs). In all, 23 C-BPTs (72.6% of isolates) were found across the sites. A representative isolate of each C-BPT was identified to the species level and tested for the presence of seven virulence genes (VGs), biofilm formation and resistance to 14 antibiotics...
October 2017: Journal of Water and Health
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