Read by QxMD icon Read

lipopolysaccharide and biofilm formation

Li-Av Segev-Zarko, Gal Kapach, Michaele Josten, Yoel Alexander Klug, Hans-Georg Sahl, Yechiel Shai
Multidrug resistant bacteria possess various mechanisms that can sense environmental stresses such as antibiotics and antimicrobial peptides, and rapidly respond to defend themselves. Two known defense strategies are biofilm formation and lipopolysaccharide (LPS) modification. Though LPS modifications are observed in biofilm embedded bacteria, their effect on biofilm formation is unknown. Using biochemical and biophysical methods coupled with confocal, atomic force microscopy and transmission electron microscopy, we show that biofilm formation is promoted in a Pseudomonas aeruginosa PAO1 strain with a loss of function mutation in the arnB gene...
March 8, 2018: Biochemistry
Zahra Farshadzadeh, Behrouz Taheri, Sara Rahimi, Saeed Shoja, Maryam Pourhajibagher, Mohammad A Haghighi, Abbas Bahador
Two different mechanisms of resistance to colistin in Acinetobacter baumannii have been described. The first involves the total loss of lipopolysaccharide (LPS) due to mutations in the lpxACD operon, which is involved in the lipid A biosynthesis pathway. The second entails the addition of ethanolamine to the lipid A of the LPS resulting from mutations in the PmrAB two-component system. To evaluate the impact of colistin resistance-associated mutations on antimicrobial resistance and virulence properties, four pairs of clinical and laboratory-evolved colistin-susceptible/colistin-resistant (ColS /ColR ) A...
2018: Frontiers in Microbiology
Noreen K Nkosana, Daniel J Czyzyk, Zarek S Siegel, Joy M Cote, Erika A Taylor
Gram-negative bacteria comprise the majority of microbes that cause infections that are resistant to pre-existing antibiotics. The complex cell wall architecture contributes to their ability to form biofilms, which are often implicated in hospital-acquired infections. Biofilms promote antibiotic resistance by enabling the bacteria to survive hostile environments such as UV radiation, pH shifts, and antibiotics. The outer membrane of Gram-negative bacteria contains lipopolysaccharide (LPS), which plays a role in adhesion to surfaces and formation of biofilms...
February 2, 2018: Bioorganic & Medicinal Chemistry Letters
Bo Wang, Guichun Wu, Yuqiang Zhang, Guoliang Qian, Fengquan Liu
Hypothetical proteins without defined functions are largely distributed in all sequenced bacterial genomes. Understanding their potent functionalities is a basic demand for bacteriologists. Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial leaf blight of rice, is one of the model systems for studying molecular plant pathology. One quarter of proteins in the genome of this bacterium were defined as hypothetical proteins, but their roles in Xoo pathogenicity is unknown. Here, we generated in-frame deletions for six hypothetical proteins selected from strain PXO99A and found one (PXO_03177) of them is required for the full virulence of this strain...
February 2, 2018: Molecular Plant Pathology
Agnieszka Zabłotni, Dominik Matusiak, Nikolay P Arbatsky, Magdalena Moryl, Anna Maciejewska, Anna N Kondakova, Alexander S Shashkov, Czesław Ługowski, Yuriy A Knirel, Antoni Różalski
The impact of planktonic and biofilm lifestyles of the clinical isolate Proteus mirabilis 9B-m on its lipopolysaccharide (O-polysaccharide, core region, and lipid A) was evaluated. Proteus mirabilis bacteria are able to form biofilm and lipopolysaccharide is one of the factors involved in the biofilm formation. Lipopolysaccharide was isolated from planktonic and biofilm cells of the investigated strain and analyzed by SDS-PAGE with silver staining, Western blotting and ELISA, as well as NMR and matrix-assisted laser desorption ionization time-of-flight mass spectrometry techniques...
January 12, 2018: Medical Microbiology and Immunology
Yasuko Sekita, Keiji Murakami, Hiromichi Yumoto, Kouji Hirao, Takashi Amoh, Natsumi Fujiwara, Katsuhiko Hirota, Hideki Fujii, Takashi Matsuo, Yoichiro Miyake, Yoshiki Kashiwada
Dental biofilms that form in the oral cavity play a critical role in the pathogenesis of several infectious oral diseases, including dental caries, periodontal disease, and oral candidiasis. Houttuynia cordata (HC, Saururaceae) is a widely used traditional medicine, for both internal and external application. A decoction of dried HC leaves (dHC) has long been consumed as a health-promoting herbal tea in Japan. We have recently reported that a water solution of HC poultice ethanol extract (wHCP) exerts antimicrobial and antibiofilm effects against several important oral pathogens...
2017: Evidence-based Complementary and Alternative Medicine: ECAM
Xiaochun Huang, Chang Chen, Chunhua Ren, Yingying Li, Yiqin Deng, Yiying Yang, Xiongqi Ding
Colanic acid (CA) is a group I extracellular polysaccharide (EPS) that contributes to resistance against adverse environments in many members of the Enterobacteriaceae. In the present study, a genetic locus EPSC putatively involved in CA biosynthesis was identified in Vibrio alginolyticus ZJ-51, which undergoes colony morphology variation between translucent/smooth (ZJ-T) and opaque/rugose (ZJ-O). EPSC in ZJ-T carries 21 ORFs and resembles the CA cluster of Escherichia coli K-12. The deletion of EPSC led to decreased EPS and biofilm formation in both genetic backgrounds but no alternation of lipopolysaccharide...
January 2018: Biofouling
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
Mafalda Faria, Nicola Bordin, Jana Kizina, Jens Harder, Damien Devos, Olga M Lage
Planctomycetes are bacteria with complex molecular and cellular biology. They have large genomes, some over 7Mb, and complex life cycles that include motile cells and sessile cells. Some live on the complex biofilm of macroalgae. Factors governing their life in this environment were investigated at the genomic level. We analyzed the genomes of three planctomycetes isolated from algal surfaces. The genomes were 6.6Mbp to 8.1Mbp large. Genes for outer-membrane proteins, peptidoglycan and lipopolysaccharide biosynthesis were present...
October 23, 2017: Genomics
Ting-Wei Chang, Shu-Yi Wei, Shih-Han Wang, Hung-Mu Wei, Yu-June Wang, Chiu-Feng Wang, Chinpan Chen, You-Di Liao
Antimicrobial peptides are important components of the host innate defense mechanism against invading pathogens, especially for drug-resistant bacteria. In addition to bactericidal activity, the 25 residue peptide TP4 isolated from Nile tilapia also stimulates cell proliferation and regulates the innate immune system in mice. In this report, TP4 hyperpolarized and depolarized the membrane potential of Pseudomonas aeruginosa at sub-lethal and lethal concentrations. It also inhibited and eradicated biofilm formation...
2017: PloS One
Esther K Riga, Maria Vöhringer, Vania Tanda Widyaya, Karen Lienkamp
Contact-active antimicrobial polymer surfaces bear cationic charges and kill or deactivate bacteria by interaction with the negatively charged parts of their cell envelope (lipopolysaccharides, peptidoglycan, and membrane lipids). The exact mechanism of this interaction is still under debate. While cationic antimicrobial polymer surfaces can be very useful for short-term applications, they lose their activity once they are contaminated by a sufficiently thick layer of adhering biomolecules or bacterial cell debris...
August 28, 2017: Macromolecular Rapid Communications
Xiaoyu Xu, Tong Tong, Xue Yang, Yaping Pan, Li Lin, Chen Li
BACKGROUND: Porphyromonas gingivalis is a major causative pathogen of chronic periodontitis. Within the inflammatory microenvironment, there exists extreme pH values, elevated temperatures and oxidative stress. Pathogens adapt to these stressful environmental conditions by regulating the transcription of virulence genes, modifying themselves with macromolecules and by aggregating and entering into a biofilm growth phase. Our previous study showed that the P. gingivalis sialidase can help cells obtain sialic acid from the environment, which is used to modify macromolecules on the surface of P...
August 18, 2017: BMC Microbiology
Yan Chen, Shasha Cai, Xue Qiao, Mali Wu, Zhilai Guo, Renping Wang, Yi-Qun Kuang, Haining Yu, Yipeng Wang
Crocodilians are regarded as possessing a powerful immune system. However, the composition and action of the crocodilian immune system have remained unclear until now. Cathelicidins, the principal family of host defense peptides, play pivotal roles in vertebrate immune defense against microbial invasions. However, cathelicidins from crocodilians have not been extensively studied to date. In the present study, six novel cathelicidins (As-CATH1-6) were identified and characterized from the endangered Chinese alligator (Alligator sinensis)...
August 10, 2017: Biochemical Journal
Dejing Shang, Xin Meng, Dongdong Zhang, Zhiru Kou
Nosocomial infections caused by Pseudomonas aeruginosa are difficult to treat due to the low permeability of its outer membrane as well as to its remarkable ability to acquire further resistance to antibiotics. Chensinin-1b exhibited antibacterial activity against the tested multiple-drug-resistant bacteria with a MIC ranging between 1.56 and 50μM, except E. cloacae strain 0320 (MREC0320), P. fluorescens strain 0322 (MRPF0322) and E. aerogenes strain 0320 (MREA0320). However, the MIC (25μM) of chensinin-1b to multiple-drug-resistant P...
November 1, 2017: Biochemical Pharmacology
Jonatas Rafael de Oliveira, Daiane de Jesus Viegas, Ana Paula Réquia Martins, Cláudio Antonio Talge Carvalho, Cristina Pacheco Soares, Samira Esteves Afonso Camargo, Antonio Olavo Cardoso Jorge, Luciane Dias de Oliveira
OBJECTIVES: This study evaluated the biological effects of the T. vulgaris L. extract., such as antimicrobial activity on planktonic cultures and mono- and polymicrobial biofilms, cytotoxicity, anti-inflammatory activity and genotoxicity. METHODS: Monomicrobial biofilms of Candida albicans, Staphylococcus aureus, Enterococcus faecalis, Streptococcus mutans and Pseudomonas aeruginosa and polymicrobial biofilms composed by C. albicans with each bacterium were formed for 48h and exposed for 5min to the plant extract...
October 2017: Archives of Oral Biology
Cristiane Santos Silva E Silva Figueiredo, Joice Castelo Branco Santos, José Artur de Aguiar Castro Junior, Vinícius Galvão Wakui, João F S Rodrigues, Mariana Oliveira Arruda, Andrea de Souza Monteiro, Valério Monteiro-Neto, Maria Rosa Quaresma Bomfim, Lucília Kato, Luís Cláudio Nascimento da Silva, Marcos Augusto Grigolin Grisotto
Plant-derived products have played a fundamental role in the development of new therapeutic agents. This study aimed to analyze antimicrobial, antibiofilm, cytotoxicity and antiproliferative potentials of the extract and fractions from leaves of Himatanthusdrasticus, a plant from the Apocynaceae family. After harvesting, H. drasticus leaves were macerated and a hydroalcoholic extract (HDHE) and fractions were prepared. Antimicrobial tests, such as agar-diffusion, Minimum Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) were carried out against several bacterial species...
May 31, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Vanessa I Francis, Emma C Stevenson, Steven L Porter
Pseudomonas aeruginosa is a versatile opportunistic pathogen capable of infecting a broad range of hosts, in addition to thriving in a broad range of environmental conditions outside of hosts. With this versatility comes the need to tightly regulate its genome to optimise its gene expression and behaviour to the prevailing conditions. Two-component systems (TCSs) comprising sensor kinases and response regulators play a major role in this regulation. This minireview discusses the growing number of TCSs that have been implicated in the virulence of P...
June 15, 2017: FEMS Microbiology Letters
Ranita Roy, Monalisa Tiwari, Gianfranco Donelli, Vishvanath Tiwari
Biofilm refers to the complex, sessile communities of microbes found either attached to a surface or buried firmly in an extracellular matrix as aggregates. The biofilm matrix surrounding bacteria makes them tolerant to harsh conditions and resistant to antibacterial treatments. Moreover, the biofilms are responsible for causing a broad range of chronic diseases and due to the emergence of antibiotic resistance in bacteria it has really become difficult to treat them with efficacy. Furthermore, the antibiotics available till date are ineffective for treating these biofilm related infections due to their higher values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), which may result in in-vivo toxicity...
March 31, 2017: Virulence
Sandro Roier, Franz G Zingl, Fatih Cakar, Stefan Schild
Outer membrane vesicle (OMV) release by Gram-negative bacteria has been observed and studied for decades. First considered as a by-product of cell lysis, it soon became evident that OMVs are actively secreted from the outer membrane (OM) of Gram-negative bacteria. Accordingly, these small particles (~ 10-300 nm in diameter) consist mainly of OM components like phospholipids (PLs), OM proteins, and lipopolysaccharides or lipooligosaccharides. However, OMVs may also comprise periplasmic, inner membrane, or cytoplasmic components...
May 10, 2016: Microbial Cell
Kourtney P Nickerson, Rachael B Chanin, Jeticia R Sistrunk, David A Rasko, Peter J Fink, Eileen M Barry, James P Nataro, Christina S Faherty
The Shigella species cause millions of cases of watery or bloody diarrhea each year, mostly in children in developing countries. While many aspects of Shigella colonic cell invasion are known, crucial gaps in knowledge regarding how the bacteria survive, transit, and regulate gene expression prior to infection remain. In this study, we define mechanisms of resistance to bile salts and build on previous research highlighting induced virulence in Shigella flexneri strain 2457T following exposure to bile salts...
June 2017: Infection and Immunity
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"