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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...
October 13, 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...
October 5, 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, Magali Remaud-Simeon, 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...
August 30, 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...
June 7, 2016: Journal of Basic Microbiology
Fabrizia Minandri, Francesco Imperi, Emanuela Frangipani, Carlo Bonchi, Daniela Visaggio, Marcella Facchini, Paolo Pasquali, Alessandra Bragonzi, Paolo Visca
Pseudomonas aeruginosa is a leading cause of hospital-acquired pneumonia and chronic lung infections in cystic fibrosis patients. Iron is essential for bacterial growth, and P. aeruginosa expresses multiple iron uptake systems, whose role in lung infection deserves further investigation. P. aeruginosa Fe(3+) uptake systems include the pyoverdine and pyochelin siderophores and two systems for heme uptake, all of which are dependent on the TonB energy transducer. P. aeruginosa also has the FeoB transporter for Fe(2+) acquisition...
August 2016: Infection and Immunity
Xintao Ni, Pan Jiang, Linlin Xing, Changcan Ou, Hui Yu, Jingjing Qi, Bingqing Sun, Junsheng Cui, Guijun Wang, Qinghai Hu
Riemerella anatipestifer infection is a severe disease confronting the duck industry worldwide. However, little is known about the molecular basis of R. anatipestifer pathogenesis. In this study, we screened 3580 transposon Tn4351 insertion mutagenesis mutants of the highly virulent strain YZb1 in a duckling infection experiment and found 29 of them to be attenuated and 28 potential virulence-associated genes were identified. Molecular characterization of transposon insertion sites showed that of the 28 screened genes, two were predicted to encode TonB-dependent outer membrane receptor (plugs), sixteen encoded enzymes, and seven encoded hypothetical proteins...
June 30, 2016: Veterinary Microbiology
Ruping Wang, Huiyong Xu, Liangcheng Du, Shan-Ho Chou, Hongxia Liu, Youzhou Liu, Fengquan Liu, Guoliang Qian
Lysobacter species are Gram-negative bacteria that are emerging as new sources of antibiotics, including HSAF (Heat Stable Antifungal Factor), which was identified from L. enzymogenes with a new mode of action. LesR, a LuxR solo, was recently shown to regulate the HSAF biosynthesis via an unidentified mechanism in L. enzymogenes OH11. Here, we used a comparative proteomic approach to identify the LesR targets and found that LesR influenced the expression of 33 proteins belonging to 10 functional groups, with 9 proteins belonging to the TBDR (TonB-Dependent Receptor) family...
2016: Scientific Reports
Hesamaddin Shirzad Aski, Mohammad Tabatabaei
Pasteurella multocida infects a wide range of animals and the infection may spread to human through animal bites and scratches. Pasteurella multocida isolates, obtained from several clinically healthy and diseased animals (bovine, sheep, goat, poultry, dog and cat), were investigated for capsule biosynthesis (capA, B, D, E and F) and expression of 22 virulence-associated genes using Polymerase Chain Reaction (PCR). Multiplex PCR results revealed expression of capA, capD and capB genes in 81 (61.83%), 30 (22...
July 2016: Microbial Pathogenesis
Sandra Matthijs, Nathalie Brandt, Marc Ongena, Wafa Achouak, Jean-Marie Meyer, Herbert Budzikiewicz
The genome of Pseudomonas thivervalensis LMG 21626(T) has been sequenced and a genomic, genetic and structural analysis of the siderophore mediated iron acquisition was undertaken. Pseudomonas thivervalensis produces two structurally new siderophores, pyoverdine PYOthi which is typical for P. thivervalensis strains and a closely related strain, and the lipopeptidic siderophore histicorrugatin which is also detected in P. lini. Histicorrugatin consists out of an eight amino acid long peptide which is linked to octanoic acid...
June 2016: Biometals: An International Journal on the Role of Metal Ions in Biology, Biochemistry, and Medicine
Daniel Pletzer, Yvonne Braun, Helge Weingart
In the present study, we characterised the putative peptide ABC transporter SppABCD, which is co-transcribed with the TonB-dependent receptor SppR in Pseudomonas aeruginosa PA14. However, our data show that this transporter complex is not involved in the uptake of peptides. The fact that the TonB-dependent receptor SppR is regulated by an iron starvation ECF sigma factor suggested that this transporter is probably involved in the uptake of xenosiderophores. Therefore, we screened culture supernatants of 23 siderophore-producing bacteria for their ability to induce the expression of the SppR-regulating ECF sigma factor...
June 2016: Antonie Van Leeuwenhoek
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