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Jeong-A Lim, Jisoo Hong, Jonguk Kim, Sunggi Heu, Eunjung Roh
Carocin D is a bacteriocin produced by Pectobacterium carotovorum subsp. carotovorum Pcc21. Carocin D inhibits the growth of P carotovorum subsp. carotovorum and closely related strains, P carotovorum subsp. carotovorum is causative bacteria for soft rot disease and leads to severe economic losses. Bacteriocins recognize and interact with a specific membrane protein of target bacteria as a receptor. To identify the receptor responsible for carocin D recognition, mutants that underwent a phenotypic change from carocin D-sensitivity to carocin D-insensitivity were screened...
December 2, 2016: FEMS Microbiology Letters
MaFeng Liu, MengYi Wang, DeKang Zhu, MingShu Wang, RenYong Jia, Shun Chen, KunFeng Sun, Qiao Yang, Ying Wu, XiaoYue Chen, Francis Biville, AnChun Cheng
Riemerella anatipestifer is a duck pathogen that has caused serious economic losses to the duck industry worldwide. Despite this, there are few reported studies of the physiological and pathogenic mechanisms of Riemerella anatipestifer infection. In previous study, we have shown that TonB1 and TonB2 were involved in hemin uptake. TonB family protein (TbfA) was not investigated, since knockout of this gene was not successful at that time. Here, we used a plasmid based gene over-expression and knockdown to investigate its function...
November 15, 2016: Scientific Reports
Laura M K Dassama, Grace E Kenney, Soo Y Ro, Eliza L Zielazinski, Amy C Rosenzweig
Methanotrophic bacteria use methane, a potent greenhouse gas, as their primary source of carbon and energy. The first step in methane metabolism is its oxidation to methanol. In almost all methanotrophs, this chemically challenging reaction is catalyzed by particulate methane monooxygenase (pMMO), a copper-dependent integral membrane enzyme. Methanotrophs acquire copper (Cu) for pMMO by secreting a small ribosomally produced, posttranslationally modified natural product called methanobactin (Mbn). Mbn chelates Cu with high affinity, and the Cu-loaded form (CuMbn) is reinternalized into the cell via an active transport process...
November 15, 2016: Proceedings of the National Academy of Sciences of the United States of America
Arthur Sikora, Benesh Joseph, Morgan Matson, Jacob R Staley, David S Cafiso
In BtuB, the Escherichia coli TonB-dependent transporter for vitamin B12, substrate binding to the extracellular surface unfolds a conserved energy coupling motif termed the Ton box into the periplasm. This transmembrane signaling event facilitates an interaction between BtuB and the inner-membrane protein TonB. In this study, continuous-wave and pulse electron paramagnetic resonance in a native outer-membrane preparation demonstrate that signaling also occurs from the periplasmic to the extracellular surface in BtuB...
November 1, 2016: Biophysical Journal
G Theriault, K K Nkongolo
Mechanisms of metal resistance have been reported in many plants but knowledge in woody species is scarce. The TonB-dependent receptors family (TBDTs) is a large group of proteins that facilitate the transport of molecules across the membrane of Gram-negative bacteria. Some evidence exists that TBDTs are involved in metal stress. The existence of a TonB-like mechanism in non-prokaryotes has not been established. The recent development of the Betula papyrifera (white birch) transcriptome has allowed the discovery of genes involved in plant adaptation to stress...
November 2, 2016: Heredity
Rhys Grinter, Inokentijs Josts, Khedidja Mosbahi, Aleksander W Roszak, Richard J Cogdell, Alexandre M J J Bonvin, Joel J Milner, Sharon M Kelly, Olwyn Byron, Brian O Smith, Daniel Walker
Iron is a limiting nutrient in bacterial infection putting it at the centre of an evolutionary arms race between host and pathogen. Gram-negative bacteria utilize TonB-dependent outer membrane receptors to obtain iron during infection. These receptors acquire iron either in concert with soluble iron-scavenging siderophores or through direct interaction and extraction from host proteins. Characterization of these receptors provides invaluable insight into pathogenesis. However, only a subset of virulence-related TonB-dependent receptors have been currently described...
October 31, 2016: Nature Communications
Luciana F Costa, Juliana P S Mol, Ana Patricia C Silva, Auricélio A Macêdo, Teane M A Silva, Geraldo E S Alves, Sebastian Winter, Maria G Winter, Eric M Velazquez, Mariana X Byndloss, Andreas J Bäumler, Renée M Tsolis, Tatiane A Paixão, Renato L Santos
Salmonella enterica serotype Typhimurium is able to expand in the lumen of the inflamed intestine through mechanisms that have not been fully resolved. Here we utilized streptomycin-pretreated mice and dextran sodium sulfate (DSS)-treated mice to investigate how pathways for S. Typhimurium iron acquisition contribute to pathogen expansion in the inflamed intestine. Competitive infection with an iron uptake-proficient S. Typhimurium strain and mutant strains lacking tonB feoB, feoB, tonB or iroN in streptomycin pretreated mice demonstrated that ferric iron uptake requiring IroN and TonB conferred a fitness advantage during growth in the inflamed intestine...
December 2016: International Journal of Medical Microbiology: IJMM
Annika Ciragan, A Sesilja Aranko, Igor Tascon, Hideo Iwaï
Intervening protein sequences (inteins) from extremely halophilic haloarchaea can be inactive under low salinity but could be activated by increasing salt contents to a specific concentration for each intein. The halo-obligatory inteins confer high solubility under both low and high salinity conditions. We showed the broad utility of salt-dependent protein splicing in cis and trans by demonstrating backbone cyclization, self-cleavage for purification, and scarless protein ligation for segmental isotopic labeling...
October 6, 2016: Journal of Molecular Biology
Curtis Balusek, James C Gumbart
BtuB is a TonB-dependent transporter that permits the high-affinity binding and transport of cobalamin (CBL), or vitamin B12, across the asymmetric outer membrane (OM) of Gram-negative bacteria. It has been shown that Ca(2+) binding is necessary for high-affinity binding of CBL to BtuB, and earlier simulations suggested that calcium ions serve to stabilize key substrate-binding extracellular loops. However, those simulations did not account for the lipopolysaccharides in the OM. To illuminate the roles of both Ca(2+) and lipopolysaccharides in protein functionality, we performed simulations of apo and Ca(2+)-loaded BtuB in symmetric and asymmetric bilayers...
October 4, 2016: Biophysical Journal
Allan Mills, Hai-Tuong Le, Franck Duong
TonB-dependent transporters are β-barrel outer membrane proteins occluded by a plug domain. Upon ligand binding, these transporters extend a periplasmic motif termed the TonB box. The TonB box permits the recruitment of the inner membrane protein complex TonB-ExbB-ExbD, which drives import of ligands in the cell periplasm. It is unknown precisely how the plug domain is moved aside during transport nor have the intermediate states between TonB recruitment and plug domain movement been characterized biochemically...
December 2016: Biochimica et Biophysica Acta
Afreenish Hassan, Anam Naz, Ayesha Obaid, Rehan Zafar Paracha, Kanwal Naz, Faryal Mehwish Awan, Syed Aun Muhmmad, Hussnain Ahmed Janjua, Jamil Ahmad, Amjad Ali
BACKGROUND: Acinetobacter baumannii has emerged as a significant nosocomial pathogen during the last few years, exhibiting resistance to almost all major classes of antibiotics. Alternative treatment options such as vaccines tend to be most promising and cost effective approaches against this resistant pathogen. In the current study, we have explored the pan-genome of A. baumannii followed by immune-proteomics and reverse vaccinology approaches to identify potential core vaccine targets...
2016: BMC Genomics
Victoria I Holden, Paul Breen, Sébastien Houle, Charles M Dozois, Michael A Bachman
UNLABELLED: Klebsiella pneumoniae is a Gram-negative pathogen responsible for a wide range of infections, including pneumonia and bacteremia, and is rapidly acquiring antibiotic resistance. K. pneumoniae requires secretion of siderophores, low-molecular-weight, high-affinity iron chelators, for bacterial replication and full virulence. The specific combination of siderophores secreted by K. pneumoniae during infection can impact tissue localization, systemic dissemination, and host survival...
2016: MBio
Alexandra S Tauzin, Elisabeth Laville, Yao Xiao, Sébastien Nouaille, Pascal Le Bourgeois, Stéphanie Heux, Jean-Charles Portais, Pierre Monsan, Eric C Martens, Gabrielle Potocki-Veronese, Florence Bordes
In prominent gut Bacteroides strains, sophisticated strategies have been evolved to achieve the complete degradation of dietary polysaccharides such as xylan, which is one of the major components of the plant cell wall. Polysaccharide Utilization Loci (PULs) consist of gene clusters encoding different proteins with a vast arsenal of functions, including carbohydrate binding, transport and hydrolysis. Transport is often attributed to TonB-dependent transporters, although major facilitator superfamily (MFS) transporters have also been identified in some PULs...
November 2016: Molecular Microbiology
Jerson Garita-Cambronero, Ana Palacio-Bielsa, María M López, Jaime Cubero
Xanthomonas arboricola pv. pruni is the causal agent of bacterial spot disease of stone fruits, a quarantinable pathogen in several areas worldwide, including the European Union. In order to develop efficient control methods for this disease, it is necessary to improve the understanding of the key determinants associated with host restriction, colonization and the development of pathogenesis. After an initial characterization, by multilocus sequence analysis, of 15 strains of X. arboricola isolated from Prunus, one strain did not group into the pathovar pruni or into other pathovars of this species and therefore it was identified and defined as a X...
2016: PloS One
Sophonie Jean, Richard A Juneau, Alison K Criss, Cynthia N Cornelissen
Neisseria gonorrhoeae successfully overcomes host strategies to limit essential nutrients, termed nutritional immunity, by production of TonB-dependent transporters (TdTs)-outer membrane proteins that facilitate nutrient transport in an energy-dependent manner. Four gonococcal TdTs facilitate utilization of iron or iron chelates from host-derived proteins, including transferrin (TbpA), lactoferrin (LbpA), and hemoglobin (HpuB), in addition to xenosiderophores from other bacteria (FetA). The roles of the remaining four uncharacterized TdTs (TdfF, TdfG, TdfH, and TdfJ) remain elusive...
October 2016: Infection and Immunity
Yuanjing Li, Jingjing Tian, Hua Tian, Xuemei Chen, Wenxiang Ping, Chunjie Tian, Hong Lei
AIMS: Low yield of bacterial cellulose (BC) is always resulted from the excessive accumulation of organic acids. Screen and selection of bacterial mutants with low organic acids accumulation is an efficient approach for improving BC production. METHODS AND RESULTS: In combination with proton suicide method (medium containing NaBr-NaBrO3 ), diethyl sulfate (DES) chemical mutagenesis coupled with (60) Co-γ irradiation treatment were performed for the screen and selection of desired mutant lines with productive BC...
July 25, 2016: Journal of Applied Microbiology
Eva Brhelova, Iva Kocmanova, Zdenek Racil, Marketa Hanslianova, Mariya Antonova, Jiri Mayer, Martina Lengerova
Minim typing is derived from the multi-locus sequence typing (MLST). It targets the same genes, but sequencing is replaced by high resolution melt analysis. Typing can be performed by analysing six loci (6MelT), four loci (4MelT) or using data from four loci plus sequencing the tonB gene (HybridMelT). The aim of this study was to evaluate Minim typing to discriminate extended-spectrum beta-lactamase producing Klebsiella pneumoniae (ESBL-KLPN) isolates at our hospital. In total, 380 isolates were analyzed. The obtained alleles were assigned according to both the 6MelT and 4MelT typing scheme...
September 2016: Diagnostic Microbiology and Infectious Disease
Mareike Rudolf, Mara Stevanovic, Chana Kranzler, Rafael Pernil, Nir Keren, Enrico Schleiff
Many cyanobacteria secrete siderophores to sequester iron. Alternatively, mechanisms to utilize xenosiderophores have evolved. The overall uptake systems are comparable to that of other bacteria involving outer membrane transporters energized by TonB as well as plasma membrane-localized transporters. However, the function of the bioinformatically-inferred components is largely not established and recent studies showed a high diversity of the complexity of the uptake systems in different cyanobacteria. Thus, we approached the systems of the filamentous Anabaena sp...
September 2016: Plant Molecular Biology
Benli Chai, Tamara V Tsoi, Shoko Iwai, Cun Liu, Jordan A Fish, Cheng Gu, Timothy A Johnson, Gerben Zylstra, Brian J Teppen, Hui Li, Syed A Hashsham, Stephen A Boyd, James R Cole, James M Tiedje
Sphingomonas wittichii strain RW1 (RW1) is one of the few strains that can grow on dibenzo-p-dioxin (DD). We conducted a transcriptomic study of RW1 using RNA-Seq to outline transcriptional responses to DD, dibenzofuran (DF), and the smectite clay mineral saponite with succinate as carbon source. The ability to grow on DD is rare compared to growth on the chemically similar DF even though the same initial dioxygenase may be involved in oxidation of both substrates. Therefore, we hypothesized the reason for this lies beyond catabolic pathways and may concern genes involved in processes for cell-substrate interactions such as substrate recognition, transport, and detoxification...
2016: PloS One
Toru Matsui, Tomohiko Nishino
Analytical conditions using chromo azurol S was validated for quantification of siderophore in aqueous samples, followed by the characterization of siderophore derived from newly isolated moderately halophilic bacteria. Conditions with good linearity between the absorbance and the siderophore concentration were obtained at a siderophore concentration less than 20 µM, in the wavelength range between 630 and 660 nm with developing time for at least 2 h. Of the halophilic bacteria isolated from Tunisian soil, Halomonas sp...
December 2016: Journal of Basic Microbiology
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