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https://www.readbyqxmd.com/read/28102305/structure-and-membrane-interactions-of-the-homodimeric-antibiotic-peptide-homotarsinin
#1
Rodrigo M Verly, Jarbas M Resende, Eduardo F C Junior, Mariana T Q de Magalhães, Carlos F C R Guimarães, Victor H O Munhoz, Marcelo Porto Bemquerer, Fábio C L Almeida, Marcelo M Santoro, Dorila Piló-Veloso, Burkhard Bechinger
Antimicrobial peptides (AMPs) from amphibian skin are valuable template structures to find new treatments against bacterial infections. This work describes for the first time the structure and membrane interactions of a homodimeric AMP. Homotarsinin, which was found in Phyllomedusa tarsius anurans, consists of two identical cystine-linked polypeptide chains each of 24 amino acid residues. The high-resolution structures of the monomeric and dimeric peptides were determined in aqueous buffers. The dimer exhibits a tightly packed coiled coil three-dimensional structure, keeping the hydrophobic residues screened from the aqueous environment...
January 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28100610/the-measles-virus-receptor-slamf1-can-mediate-particle-endocytosis
#2
Daniel Gonçalves-Carneiro, Jane A McKeating, Dalan Bailey
: The signalling lymphocyte activation molecule F1 (SLAMF1) is both a microbial sensor and entry receptor for Measles virus (MeV). Herein, we describe a new role for SLAMF1 to mediate MeV endocytosis that is in contrast with the alternative, and generally accepted, model that MeV genome enters cells only after fusion at the cell surface. We demonstrated that MeV engagement of SLAMF1 induces dramatic but transient morphological changes, most prominently in the formation of membrane blebs, which were shown to co-localise with incoming viral particles, and rearrangement of the actin cytoskeleton in infected cells...
January 18, 2017: Journal of Virology
https://www.readbyqxmd.com/read/28100498/the-predominant-cd4-th1-cytokine-elicited-to-chlamydia-trachomatis-infection-in-women-is-tumor-necrosis-factor-alpha-not-interferon-gamma
#3
Stephen J Jordan, Kanupriya Gupta, Brian M O Ogendi, Rakesh K Bakshi, Richa Kapil, Christen G Press, Steffanie Sabbaj, Jeannette Y Lee, William M Geisler
Chlamydia trachomatis infection is the most prevalent bacterial sexually transmitted infection and can cause significant reproductive morbidity in women. There is insufficient knowledge of C. trachomatis-specific immune responses in humans, which could be important in guiding vaccine development efforts. In contrast, murine models have clearly demonstrated the essential role of Type 1 T helper cells (Th1), especially interferon-gamma (IFN-γ) producing CD4(+) T-cells, in protective immunity to chlamydia. To determine the frequency and magnitude of Th1 cytokine responses elicited to C...
January 18, 2017: Clinical and Vaccine Immunology: CVI
https://www.readbyqxmd.com/read/28099884/characterization-of-human-and-staphylococcus-aureus-proteins-in-respiratory-mucosa-by-in-vivo-and-immunoproteomics
#4
Frank Schmidt, Tanja Meyer, Nandakumar Sundaramoorthy, Stephan Michalik, Kristin Surmann, Maren Depke, Vishnu Dhople, Manuela Gesell Salazar, Gabriele Holtappels, Nan Zhang, Barbara M Bröker, Claus Bachert, Uwe Völker
: Staphylococcus aureus is a Gram-positive opportunistic bacterium which can be found as a commensal in the nares of about 50% of the human population. Besides asymptomatic carriage, S. aureus has also been found to colonize nasal polyps, a subform of chronic rhinosinusitis, in 60 to 100% of cases, and even reside intracellularly in nasal polyp tissue. The aim of this study was to shed light on the behavior of S. aureus in the human airways by analyzing S. aureus-specific proteins in nasal polyp tissue from patients with chronic rhinosinusitis and to characterize the immunogenic potential of the identified (mainly secreted) proteins...
January 15, 2017: Journal of Proteomics
https://www.readbyqxmd.com/read/28099040/effect-of-bacoside-a-on-growth-and-biofilm-formation-by-staphylococcus-aureus-and-pseudomonas-aeruginosa
#5
Debaprasad Parai, Ekramul Islam, Jayati Mitra, Samir Kumar Mukherjee
The goal of this study was to evaluate the antibiofilm and antimicrobial activities of Bacoside A, a formulation of phytochemicals from Bacopa monnieri, against Staphylococcus aureus and Pseudomonas aeruginosa, which are known to form biofilms as one of their virulence traits. The antimicrobial effects of Bacoside A were tested using the minimum inhibitory concentration and minimum bactericidal concentration assays. A cell membrane disruption assay was performed to find its possible target site. MTT assay, crystal violet assay, and microscopic studies were performed to assess the antibiofilm activity...
October 24, 2016: Canadian Journal of Microbiology
https://www.readbyqxmd.com/read/28098781/distinct-neurotoxicity-profile-of-listeriolysin-o-from-listeria-monocytogenes
#6
Jana Maurer, Sabrina Hupp, Carolin Bischoff, Christina Foertsch, Timothy J Mitchell, Trinad Chakraborty, Asparouh I Iliev
Cholesterol-dependent cytolysins (CDCs) are protein toxins that originate from Gram-positive bacteria and contribute substantially to their pathogenicity. CDCs bind membrane cholesterol and build prepores and lytic pores. Some effects of the toxins are observed in non-lytic concentrations. Two pathogens, Streptococcus pneumoniae and Listeria monocytogenes, cause fatal bacterial meningitis, and both produce toxins of the CDC family-pneumolysin and listeriolysin O, respectively. It has been demonstrated that pneumolysin produces dendritic varicosities (dendrite swellings) and dendritic spine collapse in the mouse neocortex, followed by synaptic loss and astrocyte cell shape remodeling without elevated cell death...
January 13, 2017: Toxins
https://www.readbyqxmd.com/read/28096686/peptide-consensus-sequence-determination-for-the-enhancement-of-the-antimicrobial-activity-and-selectivity-of-antimicrobial-peptides
#7
Ammar Almaaytah, Ya'u Ajingi, Ahmad Abualhaijaa, Shadi Tarazi, Nizar Alshar'i, Qosay Al-Balas
The rise of multidrug-resistant bacteria is causing a serious threat to the world's human population. Recent reports have identified bacterial strains displaying pan drug resistance against antibiotics and generating fears among medical health specialists that humanity is on the dawn of entering a post-antibiotics era. Global research is currently focused on expanding the lifetime of current antibiotics and the development of new antimicrobial agents to tackle the problem of antimicrobial resistance. In the present study, we designed a novel consensus peptide named "Pepcon" through peptide consensus sequence determination among members of a highly homologous group of scorpion antimicrobial peptides...
2017: Infection and Drug Resistance
https://www.readbyqxmd.com/read/28096447/pbp1b-glycosyltransferase-and-transpeptidase-activities-play-different-essential-roles-during-the-de-novo-regeneration-of-rod-shaped-morphology-in-escherichia-coli
#8
Dev K Ranjit, Matthew A Jorgenson, Kevin D Young
: Peptidoglycan is a vital component of nearly all cell wall-bearing bacteria and is a valuable target for antibacterial therapy. However, despite decades of work, there remain important gaps in understanding how this macromolecule is synthesized and molded into a three-dimensional structure that imparts specific morphologies to individual cells. Here, we investigate the particularly enigmatic area of how peptidoglycan is synthesized and shaped during the first stages of creating cell shape de novo, that is, in the absence of a pre-existing template...
January 17, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28095880/high-throughput-expression-of-animal-venom-toxins-in-escherichia-coli-to-generate-a-large-library-of-oxidized-disulphide-reticulated-peptides-for-drug-discovery
#9
Jeremy Turchetto, Ana Filipa Sequeira, Laurie Ramond, Fanny Peysson, Joana L A Brás, Natalie J Saez, Yoan Duhoo, Marilyne Blémont, Catarina I P D Guerreiro, Loic Quinton, Edwin De Pauw, Nicolas Gilles, Hervé Darbon, Carlos M G A Fontes, Renaud Vincentelli
BACKGROUND: Animal venoms are complex molecular cocktails containing a wide range of biologically active disulphide-reticulated peptides that target, with high selectivity and efficacy, a variety of membrane receptors. Disulphide-reticulated peptides have evolved to display improved specificity, low immunogenicity and to show much higher resistance to degradation than linear peptides. These properties make venom peptides attractive candidates for drug development. However, recombinant expression of reticulated peptides containing disulphide bonds is challenging, especially when associated with the production of large libraries of bioactive molecules for drug screening...
January 17, 2017: Microbial Cell Factories
https://www.readbyqxmd.com/read/28093229/antimicrobial-activity-and-mechanism-of-pdc213-an-endogenous-peptide-from-human-milk
#10
Yazhou Sun, Yahui Zhou, Xiao Liu, Fan Zhang, Linping Yan, Ling Chen, Xing Wang, Hongjie Ruan, Chenbo Ji, Xianwei Cui, Jiaqin Wang
Human milk has always been considered an ideal source of elemental nutrients to both preterm and full term infants in order to optimally develop the infant's tissues and organs. Recently, hundreds of endogenous milk peptides were identified in human milk. These peptides exhibited angiotensin-converting enzyme inhibition, immunomodulation, or antimicrobial activity. Here, we report the antimicrobial activity and mechanism of a novel type of human antimicrobial peptide (AMP), termed PDC213 (peptide derived from β-Casein 213-226 aa)...
January 13, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28092156/inhibition-of-cronobacter-sakazakii-adhesion-to-caco-2-cells-by-commercial-dairy-powders-and-raw-buttermilk
#11
Daniel Ripollés, Saidou Harouna, José Antonio Parrón, Irene Arenales, Miguel Calvo, María Dolores Pérez, Lourdes Sánchez
Cronobacter sakazakii is a foodborne pathogen that has been associated with severe infections mainly in neonates. The binding of this bacterium to host cell surfaces represents the first step in the pathogenesis of disease. An ELISA-based assay has been developed using a polyclonal antiserum against C. sakazakii to determine its adhesion to Caco-2 cells. The antiserum used recognised many of the outer membrane proteins of C. sakazakii. A positive correlation was found between the absorbance values obtained by ELISA and the number of bacteria adhered to cells determined by plate counting...
January 16, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28091766/pre-operative-intra-articular-deep-tissue-sampling-with-novel-retrograde-forceps-improves-the-diagnostics-in-periprosthetic-joint-infection
#12
Matthias D Wimmer, Milena M Ploeger, Max J Friedrich, Thomas Hügle, Sascha Gravius, Thomas M Randau
BACKGROUND: Histopathological tissue analysis is a key parameter within the diagnostic algorithm for suspected periprosthetic joint infections (PJIs), conventionally acquired in open surgery. In 2014, Hügle and co-workers introduced novel retrograde forceps for retrograde synovial biopsy with simultaneous fluid aspiration of the knee joint. We hypothesised that tissue samples acquired by retrograde synovial biopsy are equal to intra-operatively acquired deep representative tissue samples regarding bacterial detection and differentiation of periprosthetic infectious membranes...
January 14, 2017: International Orthopaedics
https://www.readbyqxmd.com/read/28091625/mplex-a-method-for-simultaneous-pathogen-inactivation-and-extraction-of-samples-for-multi-omics-profiling
#13
Kristin E Burnum-Johnson, Jennifer E Kyle, Amie J Eisfeld, Cameron P Casey, Kelly G Stratton, Juan F Gonzalez, Fabien Habyarimana, Nicholas M Negretti, Amy C Sims, Sadhana Chauhan, Larissa B Thackray, Peter J Halfmann, Kevin B Walters, Young-Mo Kim, Erika M Zink, Carrie D Nicora, Karl K Weitz, Bobbie-Jo M Webb-Robertson, Ernesto S Nakayasu, Brian Ahmer, Michael E Konkel, Vladimir Motin, Ralph S Baric, Michael S Diamond, Yoshihiro Kawaoka, Katrina M Waters, Richard D Smith, Thomas O Metz
The continued emergence and spread of infectious agents is of great concern, and systems biology approaches to infectious disease research can advance our understanding of host-pathogen relationships and facilitate the development of new therapies and vaccines. Molecular characterization of infectious samples outside of appropriate biosafety containment can take place only subsequent to pathogen inactivation. Herein, we describe a modified Folch extraction using chloroform/methanol that facilitates the molecular characterization of infectious samples by enabling simultaneous pathogen inactivation and extraction of proteins, metabolites, and lipids for subsequent mass spectrometry-based multi-omics measurements...
January 16, 2017: Analyst
https://www.readbyqxmd.com/read/28090771/differential-adhesive-bioactive-properties-of-polymeric-surface-coated-with-graphene-oxide-thin-film
#14
Sudhin Thampi, A Maya Nandkumar, Vignesh Muthuvijayan, Ramesh Parameswaran
Surface engineering of implantable devices involving polymeric biomaterials has become an essential aspect for medical implants. Surface enhancement technique can provide an array of unique surface properties that improves its biocompatibility and functionality as an implant. Polyurethane based implants that have found extensively acclaimed usage as an implant in biomedical applications, especially in the area of cardiovascular devices still lacks any mechanism to ward off bacterial or platelet adhesion. To bring out such a defense mechanism we are proposing a surface modification technique...
January 16, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28089893/proteomic-characterization-of-the-interactions-between-fish-serum-proteins-and-waterborne-bacteria-reveals-the-suppression-of-anti-oxidative-defense-as-a-serum-mediated-antimicrobial-mechanism
#15
Miao Dong, Yimin Liang, Rajkumar Ramalingam, Sze Wing Tang, Wei Shen, Rui Ye, Singaram Gopalakrishnan, Doris Wai Ting Au, Yun Wah Lam
Fish blood is one of the crucial tissues of innate immune system, but the full repertoire of fish serum components involved in antibacterial defense is not fully identified. In this study, we demonstrated that turbot serum, but not the heat-inactivated control, significantly reduced the number of Edwardsiella tarda (E. tarda). By conjugating serum proteins with fluorescent dyes, we showed that E. tarda were coated with multiple fish proteins. In order to identify these proteins, we used E. tarda to capture turbot serum proteins and subjected the samples to shotgun proteomic analysis...
January 9, 2017: Fish & Shellfish Immunology
https://www.readbyqxmd.com/read/28089757/disorazoles-block-group-a-streptococcal-invasion-into-epithelial-cells-via-interference-with-the-host-factor-ezrin
#16
Katharina Rox, Manfred Rohde, Gursharan Singh Chhatwal, Rolf Müller
Bacterial pathogens use invasion into human cells as a strategy to escape not only the host's immune response, but also anti-bacterial treatment. This often leads to persistence and enables reinitiation of the infection process at a later time point. Here, we show that a family of myxobacterial metabolites, disorazoles, block invasion of group A Streptococcus (GAS) into human epithelial cells. Mechanistically, disorazoles target ezrin, a host protein involved in linking microfilaments to the membrane, and affect invasion most likely by interfering with dynamic phosphorylation of ezrin...
January 5, 2017: Cell Chemical Biology
https://www.readbyqxmd.com/read/28089718/cathelicidin-antimicrobial-peptide-from-alligator-mississippiensis-has-antibacterial-activity-against-multi-drug-resistant-acinetobacter-baumanii-and-klebsiella-pneumoniae
#17
Stephanie M Barksdale, Evelyn J Hrifko, Monique L van Hoek
Alligator mississippiensis (American alligator), a member of order Crocodilia, lives in bacteria-laden environments but is not often known to succumb to bacterial infections. Their serum has been shown to have antibacterial activity beyond that of human serum, and it is believed that this activity is partially due to cationic antimicrobial peptides (CAMPs). CAMPs are produced by many organisms as part of the innate immune system. CAMPs are attractive possible therapies against multi-drug resistant bacteria, such as those found in biofilm-infected war wounds, because they seldom cause genetic resistance in bacteria and are effective against antibiotic resistant bacteria...
January 12, 2017: Developmental and Comparative Immunology
https://www.readbyqxmd.com/read/28089452/co-folding-of-a-flif-flig-split-domain-forms-the-basis-of-the-ms-c-ring-interface-within-the-bacterial-flagellar-motor
#18
Michael J Lynch, Robert Levenson, Eun A Kim, Ria Sircar, David F Blair, Frederick W Dahlquist, Brian R Crane
The interface between the membrane (MS) and cytoplasmic (C) rings of the bacterial flagellar motor couples torque generation to rotation within the membrane. The structure of the C-terminal helices of the integral membrane protein FliF (FliFC) bound to the N terminal domain of the switch complex protein FliG (FliGN) reveals that FliGN folds around FliFC to produce a topology that closely resembles both the middle and C-terminal domains of FliG. The interface is consistent with solution-state nuclear magnetic resonance, small-angle X-ray scattering, in vivo interaction studies, and cellular motility assays...
December 31, 2016: Structure
https://www.readbyqxmd.com/read/28088639/docosahexaenoic-acid-loaded-lipid-nanoparticles-with-bactericidal-activity-against-helicobacter-pylori
#19
Catarina Leal Seabra, Cláudia Nunes, Maria Gomez-Lazaro, Marta Correia, José Carlos Machado, Inês C Gonçalves, Celso A Reis, Salette Reis, M Cristina L Martins
Docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid present in fish oil, has been described as a promising molecule to the treatment of Helicobacter pylori gastric infection. However, due to its highly unsaturated structure, DHA can be easily oxidized loosing part of its bioactivity. This work aims the nanoencapsulation of DHA to improve its bactericidal efficacy against H. pylori. DHA was loaded into nanostructured lipid carriers (NLC) produced by hot homogenization and ultrasonication using a blend of lipids (Precirol ATO5(®), Miglyol-812(®)) and a surfactant (Tween 60(®))...
January 11, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28088472/cholesterol-and-ergosterol-affect-the-activity-of-staphylococcus-aureus-antibiotic-efflux-pumps
#20
S R Tintino, C D M Oliveira-Tintino, F F Campina, M S Costa, R P Cruz, R L S Pereira, J C Andrade, E O Sousa, J P Siqueira-Junior, H D M Coutinho, T C Leal-Balbino, V Q Balbino
The aim of this study is to evaluate the effect of ergosterol on steroids and cholesterol efflux pumps in multidrug resistant strains of S. aureus. Were used RN4220 harboring plasmid pUL5054, which carries the gene encoding the MsrA macrolide efflux protein; and IS-58, which possesses the TetK tetracycline efflux protein; 1199B resists hydrophilic fluoroquinolones via a NorA-mediated mechanism and wild strain 1199B. The Minimal Inhibitory Concentration (MIC) was determined and the evaluation of possible inhibition of efflux pumps by reduction of MIC...
January 11, 2017: Microbial Pathogenesis
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