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bacteria membrane

Latifa Azzouz, Nouara Boudjema, Fares Aouichat, Mohamed Kherat, Nabil Mameri
This study focuses on the treatment of both organic and metallic pollution in the Staoueli landfill leachate. This leachate contains a large amount of organic and inorganic matter and it must imperatively be treated before being released into the environment. Our work presents a comparative study between two membrane sequenced batch bioreactors (B2 contains indigenous leachate bacteria and B1 contains activated sludge). The purpose is to assess the best treatment to use, one that allows the reduction of the polluting load of the leachate and a reduction of membrane fouling...
February 13, 2018: Waste Management
Nastaran Farzi, Abbas Yadegar, Hamid Asadzadeh Aghdaei, Yoshio Yamaoka, Mohammad Reza Zali
Helicobacter pylori (H. pylori) is one of the most genetically diverse bacterial pathogens that persistently colonizes the human gastric epithelium. This remarkable genomic plasticity may act as a driving force for successful adaptation and persistence of the bacteria in the harsh gastric environment. Outer inflammatory protein A (OipA) encoded by oipA gene (HP0638/hopH) is a member of the outer membrane proteins (OMPs) of H. pylori involved in induction of IL-8 secretion and is associated with development of peptic ulcer and gastric cancer...
February 13, 2018: Infection, Genetics and Evolution
Christian Eberlein, Thomas Baumgarten, Stephan Starke, Hermann J Heipieper
Bacteria have evolved an array of adaptive mechanisms enabling them to survive and grow in the presence of different environmental stresses. These mechanisms include either modifications of the membrane or changes in the overall energy status, cell morphology, and cell surface properties. Long-term adaptations are dependent on transcriptional regulation, the induction of anabolic pathways, and cell growth. However, to survive sudden environmental changes, bacterial short-term responses are essential to keep the cells alive after the occurrence of an environmental stress factor such as heat shock or the presence of toxic organic solvents...
February 15, 2018: Applied Microbiology and Biotechnology
Tsz Wai Ng, Wing Lam Chan, Ka Man Lai
Finding ways to predict and control the survival of bacterial aerosols can contribute to the development of ways to alleviate a number of crucial microbiological problems. Significant damage in the membrane integrity of Escherichia coli during aerosolization and airborne suspension has been revealed which has prompted the question of how the membrane fatty acid composition and fluidity influence the survival of airborne bacteria. Two approaches of using isogenic mutants and different growth temperatures were selected to manipulate the membrane fatty acid composition of E...
February 15, 2018: Applied Microbiology and Biotechnology
David J Sherman, Ran Xie, Rebecca J Taylor, Alexander H George, Suguru Okuda, Peter J Foster, Daniel J Needleman, Daniel Kahne
Gram-negative bacteria have an outer membrane that serves as a barrier to noxious agents in the environment. This protective function is dependent on lipopolysaccharide, a large glycolipid located in the outer leaflet of the outer membrane. Lipopolysaccharide is synthesized at the cytoplasmic membrane and must be transported to the cell surface. To understand this transport process, we reconstituted membrane-to-membrane movement of lipopolysaccharide by incorporating purified inner and outer membrane transport complexes into separate proteoliposomes...
February 16, 2018: Science
Priscila Rosseto Camiloti, Freddy Valdés, Tiago Palladino Delforno, Jan Bartacek, Marcelo Zaiat, David Jeison
A UASB (upflow anaerobic sludge blanket) reactor was operated combined to a membrane aerated biofilm reactor (MABR) for sulfate removal and for elemental sulfur reclamation. A commercial silicon tube was used as an oxygen delivery diffuser. The process achieved high rates of sulfide removal from the liquid phase (90 %). The hydrogen sulfide removal was influenced by the pH value and at pH value of 7.5, 98 % of the H 2 S was removed. The elemental sulfur was observed inside the membrane, with content in the biomass of 21 %...
February 16, 2018: Environmental Technology
R Poonguzhali, S Khaleel Basha, V Sugantha Kumari
The present study was to develop a novel chitosan based symmetric and asymmetric bionanocomposite for potential wound dressing application. Chitosan (C)/Poly (vinyl pyrrolidone) (P)/nanocellulose (NC) membrane were fabricated by salt leaching method with the addition of 3% and 5% wt of nanocellulose. To obtain asymmetric material one side of the membrane was coated by stearic acid (S) which could form hydrophobic surface and another side acts as a hydrophilic surface. Nanocellulose of size 2-10 nm was synthesized and characterized by TEM analysis...
February 12, 2018: International Journal of Biological Macromolecules
Masaki Osawa, Harold P Erickson
Bacterial cytokinesis begins with the assembly of FtsZ into a Z ring at the center of the cell. The Z-ring constriction in Gram-negative bacteria may occur in an environment where the periplasm and the cytoplasm are isoosmotic, but in Gram-positive bacteria the constriction may have to overcome a substantial turgor pressure. We address three potential sources of invagination force. (1) FtsZ itself may generate force by curved protofilaments bending the attached membrane. This is sufficient to constrict liposomes in vitro ...
2018: Frontiers in Microbiology
Wipa Suginta, Natchanok Sritho, Araya Ranok, David Bulmer, Yoshihito Kitaoku, Bert van den Berg, Tamo Fukamizo
Periplasmic solute-binding proteins (SBPs) in bacteria are involved in the active transport of nutrients into the cytoplasm. In marine bacteria of the genus Vibrio, a chitooligosaccharide-binding protein (CBP) is thought to be the major SBP controlling the rate of chitin uptake in these bacteria. However, the molecular mechanism of the CBP involvement in chitin metabolism has not been elucidated. Here, we report the structure and function of a recombinant chitooligosaccharide-binding protein from Vibrio harveyi , namely Vh CBP, expressed in Escherichia coli...
February 14, 2018: Journal of Biological Chemistry
Sunniva Katharina Thode, Ewelina Rojek, Mikolaj Kozlowski, Rafi Ahmad, Peik Haugen
Siderophores are small molecules synthesized and secreted by bacteria and fungi to scavenge iron. Extracellular ferri-siderohores are recognized by cognate receptors on the cell surface for transport over membranes. Several siderophore systems from Vibrionaceae representatives are known and well understood, e.g., the molecular structure of the siderophore, the biosynthesis gene cluster and pathway, and the gene expression pattern. Less is known about how these systems are distributed among the ~140 Vibrionaceae species, and which evolutionary processes contributed to the present-day distribution...
2018: PloS One
Rachel Santarella-Mellwig, Josef Franke, Andreas Jaedicke, Mátyás Gorjánácz, Ulrike Bauer, Aidan Budd, Iain W Mattaj, Damien P Devos
[This corrects the article DOI: 10.1371/journal.pbio.1000281.].
February 2018: PLoS Biology
Zhonghua Huang, Mengkun Li, Na Li, Xinyuan Tang, Zhiyu Ouyang
Membrane technology is now being widely used in the field of water treatment for its unique advantages. Layer-by-layer (LbL) self-assembly technique is a convenient and versatile method of modified nanofiltration (NF) membranes fabrication, which can be used to control the thickness and the surface properties of membranes by chemical deposition of polyelectrolytes. Herein, a new kind of composite NF membrane with enhanced antibacterial properties was successfully fabricated through LbL self-assembly method, having polyether sulfone (PES) ultrafiltration (UF) membrane as support layer, N-[(2-hydroxy-3-trimethylammonium)propyl] chloride chitosan (HTCC) and polyacrylic acid (PAA) as active layer, and epichlorohydrin (ECH) as crosslinking reagent...
July 1, 2018: Journal of Nanoscience and Nanotechnology
Maarten G K Ghequire, Susan K Buchanan, René De Mot
Bacteria host an arsenal of antagonism-mediating molecules to combat for ecologic space. Bacteriocins represent a pivotal group of secreted antibacterial peptides and proteins assisting in this fight, mainly eliminating relatives. Colicin M, a model for peptidoglycan-interfering bacteriocins in Gram-negative bacteria, appears to be part of a set of polymorphic toxins equipped with such a catalytic domain (ColM) targeting lipid II. Diversifying recombination has enabled parasitism of different receptors and has also given rise to hybrid bacteriocins in which ColM is associated with another toxin module...
February 13, 2018: MBio
Rilee Zeinert, Eli Martinez, Jennifer Schmitz, Katherine Senn, Bakhtawar Usman, Vivek Anantharaman, L Aravind, Lauren S Waters
Manganese is an essential trace nutrient for organisms, because of its role in cofactoring enzymes and providing protection against reactive oxygen species (ROS). Many bacteria require manganese to form pathogenic or symbiotic interactions with eukaryotic host cells. However, excess manganese is toxic, requiring cells to have manganese export mechanisms. Bacteria are currently known to possess two widely-distributed classes of manganese export proteins, MntP and MntE, but other types of transporters likely exist...
February 13, 2018: Journal of Biological Chemistry
Tamiko Nagao, Haruyuki Nakayama-Imaohji, Miad Elahi, Ayano Tada, Emika Toyonaga, Hisashi Yamasaki, Katsuichiro Okazaki, Hirokazu Miyoshi, Koichiro Tsuchiya, Tomomi Kuwahara
Excessive damage to DNA and lipid membranes by reactive oxygen species reduces the viability of bacteria. In the present study, the proliferation of recA‑deficient Escherichia coli strains was revealed to be inhibited by 1% L‑histidine under aerobic conditions. This inhibition of proliferation was not observed under anaerobic conditions, indicating that L‑histidine enhances oxidative DNA damage to E. coli cells. Reverse transcription‑quantitative polymerase chain reaction analysis demonstrated that the expression of recA in E...
February 7, 2018: International Journal of Molecular Medicine
Yijie Chen, Mengchun Chen, Yue Zhang, Joo Hee Lee, Tamara Escajadillo, Hua Gong, Ronnie H Fang, Weiwei Gao, Victor Nizet, Liangfang Zhang
Neutralization of bacterial toxins has become a compelling approach to treating bacterial infections as it may pose less selective pressure for the development of bacterial resistance. Currently, the majority of toxin neutralization platforms act by targeting the molecular structure of the toxin, which requires toxin identification and customized design for different diseases. Therefore, their development has been challenged by the enormous number and complexity of bacterial toxins. Herein, biomimetic toxin nanosponges are formulated by coating membranes of human red blood cells (hRBCs) onto polymeric nanoparticles, which act as a toxin decoy to absorb and neutralize a broad-spectrum of hemolytic toxins regardless of their molecular structure...
February 13, 2018: Advanced Healthcare Materials
Huarong Yu, Fangshu Qu, Xiaolei Zhang, Peng Wang, Guibai Li, Heng Liang
Quorum quenching (QQ) has been used to control biofouling in membrane bioreactors (MBRs), but the effect of QQ on the performance of MBR has not been systematically studied. This study investigated the effect of QQ on ammonia removal in MBR especially in some stressful conditions. The results showed that membrane fouling was effectively alleviated by QQ in all conditions. For the short HRT (3.94 h), the ammonia removal in QQ-MBR was fluctuating. In the presence of nitrification inhibitors (acetonitrile and allylthiourea) or at low temperature (10 °C), QQ induced much more significant suppression on nitrification in batch test and MBR...
February 6, 2018: Chemosphere
Michał Flasiński, Sara Kowal, Marcin Broniatowski, Pawel Wydro
Langmuir monolayers were used to study the influence of four commercially applied parabens on multicomponent systems composed of lipid species characteristic for the cellular membrane of microorganisms found in carbohydrates and proteins reach products, including food and cosmetics. The aim of the undertaken studies was to shed new light onto the problem of parabens interactions with membrane lipids and their affinity toward monolayers differing as regards the composition, mutual lipid ratios and the physicochemical properties...
February 12, 2018: Journal of Physical Chemistry. B
Lissa S Tsutsumi, John M Elmore, Uyen T Dang, Miranda J Wallace, Ravikanthreddy Marreddy, Robin B Lee, Ghee T Tan, J Hurdle, Richard E Lee, Dianqing Sun
Herein we report the antibacterial structure-activity relationships of cyclic hexapeptide wollamide analogs derived from solid-phase library synthesis. Wollamide B, a cyclic hexapeptide natural product, has been previously found to have activity against Mycobacterium bovis. To further evaluate its antimycobacterial/antibacterial potential, 27 peptides including wollamides A/B, and desotamide B, were synthesized and subsequently tested against a panel of clinically significant bacterial pathogens. Biological evaluation revealed that the cyclic scaffold, amide functionality in position I, tryptophan residue in position V, and the original stereochemistry pattern of the core scaffold were key for antituberculosis and/or antibacterial activity...
February 12, 2018: ACS Combinatorial Science
Andrej Šarc, Janez Kosel, David Stopar, Martina Oder, Matevž Dular
In sufficient concentrations, the pathogenic bacteria L. pneumophila can cause a respiratory illness that is known as the "Legionnaires" disease. Moreover, toxic Shiga strains of bacteria E. coli can cause life-threatening hemolytic-uremic syndrome. Because of the recent restrictions imposed on the usage of chlorine, outbreaks of these two bacterial species have become more common. In this study we have developed a novel rotation generator and its effectiveness against bacteria Legionella pneumophila and Escherichia coli was tested for various types of hydrodynamic cavitation (attached steady cavitation, developed unsteady cavitation and supercavitation)...
April 2018: Ultrasonics Sonochemistry
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