Read by QxMD icon Read


Maarten G K Ghequire, Başak Öztürk
Pyocins are bacteriocins secreted by Pseudomonas aeruginosa , and assist in the colonization of different niches. A major subset of these antibacterial proteins adopt a modular organization characteristic of polymorphic toxins. They comprise a receptor-binding domain, a segment enabling membrane passage, and a toxin module at the carboxy-terminus that eventually kills the target cell. To protect from its own product, bacteriocin producer strains concomitantly express an immunity gene along with the bacteriocin...
July 6, 2018: Applied and Environmental Microbiology
MaFeng Liu, Yue Huang, JiaJun Liu, Francis Biville, DeKang Zhu, MingShu Wang, RenYong Jia, Shun Chen, XinXin Zhao, Qiao Yang, Ying Wu, Shaqiu Zhang, XiaoYue Chen, YunYa Liu, Ling Zhang, Yu You, YanLing Yu, AnChun Cheng
Riemerella anatipestifer (R. anatipestifer, RA) is an important bacterial pathogen of ducks and other birds; infection with RA causes high poultry mortality and heavy economic losses in the poultry industry. However, the pathogenesis of this bacterium is poorly understood, in part due to the lack of a suitable array of methods for genetic manipulation. In this study, we first examined the efficacy of the mutated pheS gene (pheS*) as a counterselectable marker in R. anatipestifer. A suicide vector carrying pheS*, pOES, was constructed and used for markerless deletion of the gene RA0C_2053 which encode a putative TonB-dependent receptor in RA ATCC11845...
June 27, 2018: Applied Microbiology and Biotechnology
Jung-Wei Chang, Yusuke Sato, Tetsuhiro Ogawa, Takatoshi Arakawa, Shuya Fukai, Shinya Fushinobu, Haruhiko Masaki
Colicins are protein toxins produced by and toxic to Escherichia coli strains. Colicin D consists of an N-terminal domain (NTD), central domain (CD), and C-terminal RNase domain (CRD). The cognate immunity protein, ImmD, is co-synthesized in producer cells to block the toxic tRNase activity of the CRD. Previous studies have reported the crystal structure of CRD/ImmD complex. Colicin D hijacks the surface receptor FepA and the energy transducer TonB system using the NTD for translocation across the outer membrane of the target cells...
June 14, 2018: Journal of Biochemistry
Khedidja Mosbahi, Marta Wojnowska, Amaya Albalat, Daniel Walker
Iron is an essential micronutrient for most bacteria and is obtained from iron-chelating siderophores or directly from iron-containing host proteins. For Gram-negative bacteria, classical iron transport systems consist of an outer membrane receptor, a periplasmic binding protein, and an inner membrane ABC transporter, which work in concert to deliver iron from the cell surface to the cytoplasm. We recently showed that Pectobacterium spp. are able to acquire iron from ferredoxin, a small and stable 2Fe-2S iron sulfur cluster containing protein and identified the ferredoxin receptor, FusA, a TonB-dependent receptor that binds ferredoxin on the cell surface...
June 11, 2018: Proceedings of the National Academy of Sciences of the United States of America
MaFeng Liu, Mi Huang, Yun Shui, Francis Biville, DeKang Zhu, MingShu Wang, RenYong Jia, Shun Chen, KunFeng Sun, XinXin Zhao, Qiao Yang, Ying Wu, XiaoYue Chen, AnChun Cheng
Iron is one of the most important elements for bacterial survival and pathogenicity. The iron uptake mechanism of Riemerella anatipestifer (R. anatipestifer, RA), a major pathogen that causes septicemia and polyserositis in ducks, is largely unknown. Here, the functions of the putative TonB-dependent iron transporter of RA-CH-1, B739_1343, in iron utilization and pathogenicity were investigated. Under iron-starved conditions, the mutant strain RA-CH-1ΔB739_1343 exhibited more seriously impaired growth than the wild-type strain RA-CH-1, and the expression of B739_1343 in the mutant strain restored growth...
2018: PloS One
Tobias A Obando S, Michael M Babykin, Vladislav V Zinchenko
The unicellular freshwater cyanobacterium Synechocystis sp. PCC 6803 is capable of using dihydroxamate xenosiderophores, either ferric schizokinen (FeSK) or a siderophore of the filamentous cyanobacterium Anabaena variabilis ATCC 29413 (SAV), as the sole source of iron in the TonB-dependent manner. The fecCDEB1-schT gene cluster encoding a siderophore transport system that is involved in the utilization of FeSK and SAV in Synechocystis sp. PCC 6803 was identified. The gene schT encodes TonB-dependent outer membrane transporter, whereas the remaining four genes encode the ABC-type transporter FecB1CDE formed by the periplasmic binding protein FecB1, the transmembrane permease proteins FecC and FecD, and the ATPase FecE...
May 21, 2018: Current Microbiology
Yang Zhang, Jie Gao, Lushan Wang, Shuangjiang Liu, Zhihui Bai, Xuliang Zhuang, Guoqiang Zhuang
Paracoccus denitrificans is a valuable model organism due to its versatile respiration capability and bioenergetic flexibility, both of which are critical to its survival in different environments. Quorum sensing (QS) plays a crucial role in the regulation of many cell functions; however, whether QS systems play a role in P. denitrificans is unknown. In this study, we demonstrated that iron uptake systems in P. denitrificans were directly regulated by a newly identified QS system. Genes coding for TonB-dependent systems, which transport chelated iron, were transcribed at higher levels in the QS-defective mutants...
May 18, 2018: Applied and Environmental Microbiology
Zhangcheng Li, Fangjun Cheng, Shimei Lan, Jianhua Guo, Wei Liu, Xiaoyan Li, Zeli Luo, Manli Zhang, Juan Wu, Yang Shi
Fowl cholera caused by Pasteurella multocida has always been a disease of global importance for poultry production. The aim of this study was to obtain more information about the epidemiology of avian P. multocida infection in southwest China and the genetic characteristics of clinical isolates. P. multocida isolates were characterized by biochemical and molecular-biological methods. The distributions of the capsular serogroups, the phenotypic antimicrobial resistance profiles, lipopolysaccharide (LPS) genotyping and the presence of 19 virulence genes were investigated in 45 isolates of P...
April 25, 2018: Journal of Veterinary Medical Science
Saori Maki-Yonekura, Rei Matsuoka, Yoshiki Yamashita, Hirofumi Shimizu, Maiko Tanaka, Fumie Iwabuki, Koji Yonekura
Gram-negative bacteria import essential nutrients such as iron and vitamin B12 through outer membrane receptors. This process utilizes proton motive force harvested by the Ton system made up of three inner membrane proteins, ExbB, ExbD and TonB. ExbB and ExbD form the proton channel that energizes uptake through TonB. Recently, crystal structures suggest that the ExbB pentamer is the scaffold. Here, we present structures of hexameric complexes of ExbB and ExbD revealed by X-ray crystallography and single particle cryo-EM...
April 17, 2018: ELife
Alexandre Luscher, Lucile Moynié, Pamela Saint Auguste, Dirk Bumann, Lena Mazza, Daniel Pletzer, James H Naismith, Thilo Köhler
The conjugation of siderophores to antimicrobial molecules is an attractive strategy to overcome the low outer membrane permeability of Gram-negative bacteria. In this Trojan horse approach, the transport of drug conjugates is redirected via TonB-dependent receptors (TBDR), which are involved in the uptake of essential nutrients, including iron. Previous reports have demonstrated the involvement of the TBDRs PiuA and PirA from Pseudomonas aeruginosa and their orthologues in Acinetobacter baumannii in the uptake of siderophore-beta-lactam drug conjugates...
June 2018: Antimicrobial Agents and Chemotherapy
David N Bolam, Bert van den Berg
The lower human gastro-intestinal tract is inhabited by an extremely high density of micro-organisms, collectively termed the colonic microbiota. Just two bacterial phyla dominate this habitat, the Gram-positive Firmicutes and the Gram-negative Bacteroidetes. The colon is further characterised by a relative lack of small, easily accessible nutrients such as simple sugars, lipids and amino acids. Instead, a plethora of diet-derived and host polysaccharides constitute the main source of nutrients. Due to their size and complexity, the uptake of such glycans for metabolic utilisation is an energy-dependent process, which in Bacteroides spp...
March 15, 2018: Current Opinion in Structural Biology
Sajad Abdollahi, Iraj Rasooli, Seyed Latif Mousavi Gargari
Acinetobacter baumannii is an opportunistic multidrug resistant pathogen. TonB-dependent copper receptor is an outer membrane protein and has a role in binding of A. baumannii to host cell via attachment to fibronectin. Moreover, it is highly expressed in biofilm community. In this study the properties of copper receptor were analyzed in silico and its vaccine potential was investigated. TonB-dependent copper and iron receptor domains plus one plug domain at N-terminal were determined by domain analysis. Topology modeling showed 22 β-strands, 11 loops and 10 periplasmic turns...
May 2018: Microbial Pathogenesis
Leah Schwiesow, Erin Mettert, Yahan Wei, Halie K Miller, Natalia G Herrera, David Balderas, Patricia J Kiley, Victoria Auerbuch
Despite the mammalian host actively sequestering iron to limit pathogenicity, heme (or hemin when oxidized) and hemoproteins serve as important sources of iron for many bloodborne pathogens. The HmuRSTUV hemin uptake system allows Yersinia species to uptake and utilize hemin and hemoproteins as iron sources. HmuR is a TonB-dependent outer membrane receptor for hemin and hemoproteins. HmuTUV comprise a inner membrane ABC transporter that transports hemin and hemoproteins from the periplasmic space into the bacterial cytoplasm, where it is degraded by HmuS...
2018: Frontiers in Cellular and Infection Microbiology
Sajad Abdollahi, Iraj Rasooli, Seyed Latif Mousavi Gargari
Acinetobacter baumannii is an opportunistic gram negative pathogen that can adhere to different surfaces and cause different nosocomial infections. To investigate the role of TonB-dependent copper receptor, an outer membrane protein, in virulence of A. baumannii, we deleted this receptor from A. baumannii chromosome. There was a significant decrease in biofilm formation by copper receptor deficient mutant strain. Similarly, the adherence to human epithelial cell and the hydrophobicity were declined. The survival rate of the mutant strain in human sera was reduced while no change was observed in motility of strains...
June 2018: Infection, Genetics and Evolution
Grace E Kenney, Amy C Rosenzweig
Methanobactins (Mbns) are ribosomally produced, post-translationally modified natural products that bind copper with high affinity and specificity. Originally identified in methanotrophic bacteria, which have a high need for copper, operons encoding these compounds have also been found in many non-methanotrophic bacteria. The proteins responsible for Mbn biosynthesis include several novel enzymes. Mbn transport involves export through a multidrug efflux pump and re-internalization via a TonB-dependent transporter...
March 30, 2018: Journal of Biological Chemistry
Jessica L Sarver, Michael Zhang, Lishan Liu, David Nyenhuis, David S Cafiso
Bacterial outer membrane TonB-dependent transporters function by executing cycles of binding and unbinding to the inner membrane protein TonB. In the vitamin B12 transporter BtuB and the ferric citrate transporter FecA, substrate binding increases the periplasmic exposure of the Ton box, an energy-coupling segment. This increased exposure appears to enhance the affinity of the transporter for TonB. Here, continuous wave and pulse EPR spectroscopy were used to examine the state of the Ton box in the Escherichia coli ferrichrome transporter FhuA...
February 13, 2018: Biochemistry
Tally Rosenberg, Bolaji Babajide Salam, Saul Burdman
Acidovorax citrulli is the causal agent of bacterial fruit blotch of cucurbits. We have shown that functional type IV pili (T4P) are required for full virulence of this bacterium. To identify A. citrulli genes required for T4P activity, we screened a library of about 10,000 transposon mutants of A. citrulli M6 for altered T4P-mediated twitching motility. This screen led to the identification of 50 mutants impaired in twitching ability due to transposon insertions into 20 different genes. Representative mutants with disruptions in these genes were further characterized...
May 2018: Molecular Plant-microbe Interactions: MPMI
Haiyuan Cai, Yonghui Zeng
Aquidulcibacter paucihalophilus TH1-2T is a member of the family Caulobacteraceae within Alphaproteobacteria isolated from cyanobacterial aggregates in a eutrophic lake. The draft genome comprises 3,711,627 bp and 3489 predicted protein-coding genes. The genome of strain TH1-2T has 270 genes encoding peptidases. And metallo and serine peptidases were found most frequently. A high number of genes encoding carbohydrate active enzymes (141 CAZymes) also present in strain TH1-2T genome. Among CAZymes, 47 glycoside hydrolase families, 37 glycosyl transferase families, 38 carbohydrate esterases families, nine auxiliary activities families, seven carbohydrate-binding modules families, and three polysaccharide lyases families were identified...
2017: Standards in Genomic Sciences
Fang-Fang Wang, Shou-Ting Cheng, Yao Wu, Bao-Zhen Ren, Wei Qian
Recognition of the host plant is a prerequisite for infection by pathogenic bacteria. However, how bacterial cells sense plant-derived stimuli, especially chemicals that function in regulating plant development, remains completely unknown. Here, we have identified a membrane-bound histidine kinase of the phytopathogenic bacterium Xanthomonas campestris, PcrK, as a bacterial receptor that specifically detects the plant cytokinin 2-isopentenyladenine (2iP). 2iP binds to the extracytoplasmic region of PcrK to decrease its autokinase activity...
December 5, 2017: Cell Reports
Sayak Bhattacharya, Jayanta Debabrata Choudhury, Ratan Gachhui, Joydeep Mukherjee
The primary pathogen of the Great Barrier Reef sponge Rhopaloeides odorabile, recently identified as a novel strain (NW4327) of Pseudoalteromonas agarivorans, produced collagenase which degraded R. odorabile skeletal fibers. We now report the collagenase of P. agarivorans as a metalloprotease which required Ca2+ and Zn2+ as cofactors. The collagenase was a TonB dependent receptor (TBDR) having a carboxypeptidase regulatory like domain (CRLD) in the N-terminal along with an outer membrane (OM) channel superfamily domain...
April 1, 2018: International Journal of Biological Macromolecules
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"