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Bacteria cell membrane

Muhammad Ali, Dario Rangel Shaw, Lei Zhang, Mohamed Fauzi Haroon, Yuko Narita, Abdul-Hamid Emwas, Pascal E Saikaly, Satoshi Okabe
Anaerobic ammonium-oxidizing (anammox) bacteria are well known for their aggregation ability. However, very little is known about cell surface physicochemical properties of anammox bacteria and thus their aggregation abilities have not been quantitatively evaluated yet. Here, we investigated the aggregation abilities of three different anammox bacterial species: "Candidatus Brocadia sinica", "Ca. Jettenia caeni" and "Ca. Brocadia sapporoensis". Planktonic free-living enrichment cultures of these three anammox species were harvested from the membrane bioreactors (MBRs)...
June 12, 2018: Water Research
Hendrik Sielaff, Thomas M Duncan, Michael Börsch
F-type ATP synthases are extraordinary multisubunit proteins that operate as nanomotors. The Escherichia coli (E. coli) enzyme uses the proton motive force (pmf) across the bacterial plasma membrane to drive rotation of the central rotor subunits within a stator subunit complex. Through this mechanical rotation, the rotor coordinates three nucleotide binding sites that sequentially catalyze the synthesis of ATP. Moreover, the enzyme can hydrolyze ATP to turn the rotor in the opposite direction and generate pmf...
June 19, 2018: Biochimica et Biophysica Acta
S Jiang, J Zeng, X Zhou, Y Li
Growing evidence suggests the existence of new antibiotic resistance mechanisms. Recent studies have revealed that quorum-quenching enzymes, such as MacQ, are involved in both antibiotic resistance and cell-cell communication. Furthermore, some small bacterial regulatory RNAs, classified into RNA attenuators and small RNAs, modulate the expression of resistance genes. For example, small RNA sprX, can shape bacterial resistance to glycopeptide antibiotics via specific downregulation of protein SpoVG. Moreover, some bacterial lipocalins capture antibiotics in the extracellular space, contributing to severe multidrug resistance...
June 1, 2018: Journal of Dental Research
Kazuhisa Iwabuchi
Although individuals are constantly exposed to infectious agents, these agents are generally resisted by the innate and acquired immune systems. Both the innate and acquired immune systems protect against invading organisms, but they differ functionally in several ways. The innate immune system is the body's inborn defense mechanism and the first line of defense against invading organisms, such as bacteria, fungi, and viruses. Glycosphingolipids (GSLs), which are expressed on the outer leaflet of plasma membranes (Murate et al...
2018: Methods in Molecular Biology
Alina Pushkarev, Keiichi Inoue, Shirley Larom, José Flores-Uribe, Manish Singh, Masae Konno, Sahoko Tomida, Shota Ito, Ryoko Nakamura, Satoshi P Tsunoda, Alon Philosof, Itai Sharon, Natalya Yutin, Eugene V Koonin, Hideki Kandori, Oded Béjà
Many organisms capture or sense sunlight using rhodopsin pigments1,2 , which are integral membrane proteins that bind retinal chromophores. Rhodopsins comprise two distinct protein families 1 , type-1 (microbial rhodopsins) and type-2 (animal rhodopsins). The two families share similar topologies and contain seven transmembrane helices that form a pocket in which retinal is linked covalently as a protonated Schiff base to a lysine at the seventh transmembrane helix2,3 . Type-1 and type-2 rhodopsins show little or no sequence similarity to each other, as a consequence of extensive divergence from a common ancestor or convergent evolution of similar structures 1 ...
June 20, 2018: Nature
Shuo-Hsi Tang, Maria Ysabel Domino, Antoine Venault, Hao-Tung Lin, Chun Hsieh, Akon Higuchi, Arunachalam Chinnathambi, Sulaiman Ali Alharbi, Lemmuel L Tayo, Yung Chang
Poly(ethylene terephtalate) (PET)-based materials face general biofouling issues that we addressed by grafting a copolymer of glycidyl methacrylate and sulfobetaine methacrylate, poly(GMA-r-SBMA). The grafting procedure involved a dip-coating step followed by UV-exposure and led to successful grafting of the copolymer as evidenced by XPS and zeta-potential measurements.It did not modify the pore size nor the porosity of the PET membranes. In addition, their surface hydrophilicity was considerably improved, with a water contact angle falling to 30° in less than 20 s and 0° in less than one minute...
June 20, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Angela Carolina Finato, Thais Fernanda Fraga-Silva, Amanda Uliana Carvalho Prati, Amauri Alves de Souza Júnior, Bruna Fonseca Mazzeu, Lidiane Gaspareto Felippe, Rute Alves Pinto, Marjorie de Assis Golim, Maria Sueli Parreira Arruda, Maysa Furlan, James Venturini
In this study, we aimed to evaluate the immunomodulatory effects of crude leaf extracts from Piper gaudichaudianum Kunth, P. arboreum Aub., P. umbellata L., P. fuligineum Kunth, and Peperomia obtusifolia A. Dietr. on an in vitro model of inflammatory response. The crude extracts were previously obtained by maceration of the leaves. The half-maximal inhibitory concentration was determined by the MTT assay using human peripheral blood mononuclear cells. Human monocytes were simultaneously challenged with each crude extract and lipopolysaccharide (LPS), the major component of the outer membrane of Gram-negative bacteria, to induce a strong inflammatory response...
2018: PloS One
Alexander Simonis, Alexandra Schubert-Unkmeir
Acid sphingomyelinase (ASM) is a key enzyme in sphingolipid metabolism that converts sphingomyelin to ceramide, thereby modulating membrane structures and signal transduction. Bacterial pathogens can manipulate ASM activity and function, and use host sphingolipids during multiple steps of their infection process. An increase in ceramides upon infection results in the formation of ceramide-enriched membrane platforms that serve to cluster receptor molecules and organize intracellular signaling molecules, thus facilitating bacterial uptake...
June 1, 2018: Biological Chemistry
Carlise Hannel Ferreira, Sabrina Candido Nunes, Vidiany Aparecida Queiroz Santos, Ernesto Chaves Pereira, Mariana de Souza Sikora
Photocatalysis over TiO2 substrates is widely used in effluent treatment specially for organic compounds and for inactivation of pathogenic microorganisms. In the present work, TiO2 coatings were synthesized by plasma electrolytic oxidation (PEO) and its pathogenic bacteria inhibitory photoactivity was investigated. The photocatalytic activity of TiO2 coatings were investigated for the inactivation of Staphylococcus aureus and Salmonella bongori and the results were correlated with pore diameter and crystallite size...
June 20, 2018: Environmental Technology
Matias Fingermann, Lucía Avila, Maria Belén De Marco, Luciana Vázquez, Darío Nicolás Di Biase, Andrea Verónica Müller, Mirta Lescano, José Christian Dokmetjian, Sonsire Fernández Castillo, José Luis Pérez Quiñoy
Strains of Shiga toxin-producing Escherichia coli (STEC) can cause the severe Hemolytic Uremic Syndrome (HUS). Shiga toxins are protein toxins that bind and kill microvascular cells, damaging vital organs. No specific therapeutics or vaccines have been licensed for use in humans yet. The most common route of infection is by consumption of dairy or farm products contaminated with STEC. Domestic cattle colonized by STEC strains represent the main reservoir, and thus a source of contamination. Outer Membrane Vesicles (OMV) obtained after detergent treatment of gram-negative bacteria have been used over the past decades for producing many licensed vaccines...
June 20, 2018: Human Vaccines & Immunotherapeutics
Nadja Heinz Ernst, Analise Z Reeves, Julia E Ramseyer, Cammie F Lesser
Numerous Gram-negative bacterial pathogens utilize type III secretion systems (T3SSs) to inject tens of effector proteins directly into the cytosol of host cells. Through interactions with cognate chaperones, type III effectors are defined and recruited to the sorting platform, a cytoplasmic component of these membrane-embedded nanomachines. However, notably, a comprehensive review of the literature reveals that the secretion of most type III effectors has not yet been linked to a chaperone, raising questions regarding the existence of unknown chaperones as well as the universality of chaperones in effector secretion...
June 19, 2018: MBio
Radhe Shyam, Nicolas Charbonnel, Aurélie Job, Christelle Blavignac, Christiane Forestier, Claude Taillefumier, Sophie Faure
Amphipathic cationic peptoids (N-substituted glycine oligomers) represent a promising class of antimicrobial peptide mimics. The aim of this study is to explore the potential of the triazolium group as a cationic moiety and helix inducer to develop potent antimicrobial helical peptoids. We report here the first solid-phase synthesis of peptoid oligomers incorporating 1,2,3-triazolium-type side chains, and their evaluation against Escherichia coli, Enterococcus faecalis and Staphylococcus aureus. Several triazolium-based oligomers, even of short length, selectively kill bacteria over mammalian cells...
June 19, 2018: ChemMedChem
Jai W Mehat, Simon F Park, Arnoud H M van Vliet, Roberto M La Ragione
Campylobacter jejuni is recognized as an important causative agent of bacterial gastroenteritis in the developed world. Despite the identification of several factors contributing to infection, characterization of the virulence strategies employed by C. jejuni remains a significant challenge. Bacterial autotransporter proteins are a major class of secretory proteins in Gram-negative bacteria and notably many autotransporter proteins contribute to bacterial virulence. The aim of this study was to characterise the C...
June 18, 2018: Applied and Environmental Microbiology
Casey Bryce, Mirita Franz-Wachtel, Nicolas Nalpas, Jennyfer Miot, Karim Benzerara, James M Byrne, Sara Kleindienst, Boris Macek, Andreas Kappler
The oxidation of Fe(II) by anoxygenic photosynthetic bacteria was likely a key contributor to Earth's biosphere prior to the evolution of oxygenic photosynthesis and is still found in a diverse range of modern environments. All known phototrophic Fe(II)-oxidizers can utilize a wide range of substrates thus making them very metabolically flexible. However, the underlying adaptations required to oxidize Fe(II), a potential stressor, are not completely understood. We used a combination of quantitative proteomics and cryogenic transmission electron microscopy (cryo-TEM) to compare cells of Rhodopseudomonas palustris TIE-1 grown photoautotrophically with Fe(II) or H2 , and photoheterotrophically with acetate...
June 18, 2018: Applied and Environmental Microbiology
Kimberly A Harris, Zhiyuan Zhou, Michelle L Peters, Sarah G Wilkins, Ronald R Breaker
OLE (ornate, large, extremophilic) RNAs comprise a class of structured noncoding RNAs (ncRNAs) found in many extremophilic bacteria species. OLE RNAs constitute one of the longest and most widespread bacterial ncRNA classes whose major biochemical function remains unknown. In the Gram-positive alkaliphile Bacillus halodurans , OLE RNA is abundant, and localizes to the cell membrane by association with the transmembrane OLE-associated protein called OapA (formerly OAP). These characteristics, along with the well-conserved sequence and structural features of OLE RNAs, suggest that the OLE ribonucleoprotein (RNP) complex performs important biological functions...
June 18, 2018: Proceedings of the National Academy of Sciences of the United States of America
Inês N Silva, Filipa D Pessoa, Marcelo J Ramires, Mário R Santos, Jörg D Becker, Vaughn S Cooper, Leonilde M Moreira
Bacteria from the Burkholderia cepacia complex grow in different natural and man-made environments and are feared opportunistic pathogens that cause chronic respiratory infections in cystic fibrosis patients. Previous studies showed that Burkholderia mucoid clinical isolates grown under stress conditions give rise to nonmucoid variants devoid of the exopolysaccharide cepacian. Here, we have determined that a major cause of the nonmucoid morphotype involves nonsynonymous mutations and small indels in the ompR gene encoding a response regulator of a two-component regulatory system...
June 18, 2018: Journal of Bacteriology
Francesca Micoli, Roberto Adamo, Paolo Costantino
Currently licensed glycoconjugate vaccines are composed of a carbohydrate moiety covalently linked to a protein carrier. Polysaccharides are T-cell independent antigens able to directly stimulate B cells to produce antibodies. Disease burden caused by polysaccharide-encapsulated bacteria is highest in the first year of life, where plain polysaccharides are not generally immunogenic, limiting their use as vaccines. This limitation has been overcome by covalent coupling carbohydrate antigens to proteins that provide T cell epitopes...
June 15, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Isabele Fattori Moretti, Daiane Gil Franco, Thais Fernanda de Almeida Galatro, Sueli Mieko Oba-Shinjo, Suely Kazue Nagahashi Marie
Toll-like receptors (TLRs) are the first to identify disturbances in the immune system, recognizing pathogens such as bacteria, fungi, and viruses. Since the inflammation process plays an important role in several diseases, TLRs have been considered potential therapeutic targets, including treatment for cancer. However, TLRs' role in cancer remains ambiguous. This study aims to analyze the expression levels of plasmatic cell membrane TLRs (TLR1, TLR2, TLR4, TLR5, and TLR6) in human astrocytomas the most prevalent tumors of CNS different grades (II-IV)...
2018: PloS One
Mechthild Pohlschroder, Friedhelm Pfeiffer, Stefan Schulze, Mohd Farid Abdul Halim
Cell surfaces are critical for diverse functions across all domains of life, from cell-cell communication and nutrient uptake to cell stability and surface attachment. While certain aspects of the mechanisms supporting the biosynthesis of the archaeal cell surface are unique, likely due to important differences in cell surface compositions between domains, others are shared with bacteria or eukaryotes or both. Based on recent studies completed on a phylogenetically diverse array of archaea, from a wide variety of habitats, here we discuss advances in the characterization of mechanisms underpinning archaeal cell surface biogenesis...
June 15, 2018: FEMS Microbiology Reviews
Yangying Sun, Xiaojun Cai, Jinxuan Cao, Zhen Wu, Daodong Pan
Salmonella is gram-negative foodborne zoonotic bacteria which triggers disease in humans. Our previous studies showed 1,8-cineole possessed remarkable antimicrobial effects on foodborne zoonotic bacteria indicating it could serve as a new source of antibiotic for Salmonella . Present study elucidated the antibacterial mechanism of 1,8-cineole by analyzing serum protein expressed by Salmonella following treatment with 1,8-cineole (0.25 mg/mL, 3 h) using isobaric tags for relative and absolute quantification (iTRAQ) with two-dimensional liquid chromatography/tandem mass spectrometry (2D-LC-MS/MS)...
2018: Frontiers in Microbiology
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