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https://www.readbyqxmd.com/read/29124849/metaproteomics-reveals-major-microbial-players-and-their-metabolic-activities-during-the-blooming-period-of-a-marine-dinoflagellate-prorocentrum-donghaiense
#1
Dong-Xu Li, Hao Zhang, Xiao-Huang Chen, Zhang-Xian Xie, Yong Zhang, Shu-Feng Zhang, Lin Lin, Feng Chen, Da-Zhi Wang
Interactions between bacteria and phytoplankton during bloom events are essential for both partners, which impacts their physiology, alters ambient chemistry and shapes ecosystem diversity. Here, we investigated the community structure and metabolic activities of free-living bacterioplankton in different blooming phases of a dinoflagellate Prorocentrum donghaiense using a metaproteomic approach. The Fibrobacteres-Chlorobi-Bacteroidetes group, Rhodobacteraceae, SAR11 and SAR86 clades contributed largely to the bacterial community in the middle-blooming phase while the Pseudoalteromonadaceae exclusively dominated in the late-blooming phase...
November 10, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/29112082/a-pilot-study-measuring-the-novel-satiety-hormone-pro-uroguanylin-in-adolescents-with-and-without-obesity
#2
Matthew D Di Guglielmo, Dalal Tonb, Zhaoping He, Adebowale Adeyemi, Kenneth L van Golen
OBJECTIVE: Disruption of satiety signaling may lead to increased caloric intake and obesity. Uroguanylin, the intestinal hormone, travels as a precursor to the central nervous system where it activates guanylyl cyclase C (GUCY2C) and stimulates pro-satiety neurons. Rodent studies have demonstrated that (1) GUCY2C-knockout mice over-eat and have increased weight gain vs. wild-type mice; and (2) hyper-caloric obesity diminishes uroguanylin expression. We measured circulating plasma pro-uroguanylin, along with other gastrointestinal peptides and inflammatory markers, in human adolescents with and without obesity, as a pilot study...
November 3, 2017: Journal of Pediatric Gastroenterology and Nutrition
https://www.readbyqxmd.com/read/29079615/%C3%AE-glucanase-activity-of-the-oral-bacterium-tannerella-forsythia-contributes-to-the-growth-of-a-partner-species-fusobacterium-nucleatum-in-co-biofilms
#3
Kiyonobu Honma, Angela Ruscitto, Ashu Sharma
Tannerella forsythia and Fusobacterium nucleatum are dental plaque bacteria implicated in the development of periodontitis. These two species have been shown to form synergistic biofilms and found to be closely associated in dental plaque biofilms. A number of genetic loci for TonB-dependent membrane receptors (TDR) for glycan acquisition, with many existing in association with genes coding for enzymes involved in the breakdown of complex glycans, have been identified in T. forsythia In this study, we focused on a locus, BFO_0186 -- BFO_0188, that codes for a predicted TDR-SusD transporter along with a putative β-glucan hydrolyzing enzyme (BFO_0186)...
October 27, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29078392/exploitation-of-an-iron-transporter-for-bacterial-protein-antibiotic-import
#4
Paul White, Amar Joshi, Patrice Rassam, Nicholas G Housden, Renata Kaminska, Jonathan D Goult, Christina Redfield, Laura C McCaughey, Daniel Walker, Shabaz Mohammed, Colin Kleanthous
Unlike their descendants, mitochondria and plastids, bacteria do not have dedicated protein import systems. However, paradoxically, import of protein bacteriocins, the mechanisms of which are poorly understood, underpins competition among pathogenic and commensal bacteria alike. Here, using X-ray crystallography, isothermal titration calorimetry, confocal fluorescence microscopy, and in vivo photoactivatable cross-linking of stalled translocation intermediates, we demonstrate how the iron transporter FpvAI in the opportunistic pathogen Pseudomonas aeruginosa is hijacked to translocate the bacteriocin pyocin S2 (pyoS2) across the outer membrane (OM)...
October 25, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29071576/nmr-assignments-of-the-n-terminal-signaling-domain-of-the-tonb-dependent-outer-membrane-transducer-pupb
#5
Jaime L Jensen, Qiong Wu, Christopher L Colbert
Outer membrane TonB-dependent transducers (TBDTs) actively transport ferric siderophore complexes from the extracellular environment into Gram-negative bacteria. They also participate in a cell-surface signaling regulatory pathway that results in upregulation of the transducer itself, in response to iron-deplete conditions. The TBDT PupB transports ferric pseudobactin, and signals through its N-terminal signaling domain (NTSD), while the TBDT homolog PupA is signaling-inactive. Here, we report the NMR chemical shift assignments of the PupB-NTSD...
October 25, 2017: Biomolecular NMR Assignments
https://www.readbyqxmd.com/read/28956836/characterization-of-the-burkholderia-cenocepacia-tonb-mutant-as-a-potential-live-attenuated-vaccine
#6
Gonzalo A Pradenas, Julia N Myers, Alfredo G Torres
Burkholderia cenocepacia is an opportunistic pathogen prevalent in cystic fibrosis patients, which is particularly difficult to treat, causing chronic and eventually fatal infections. The lack of effective treatment options makes evident the need to develop alternative therapeutic or prophylactic approaches. Vaccines, and live attenuated vaccines, are an unexplored avenue to treat B. cenocepacia infections. Here we constructed and characterized a B. cenocepacia tonB mutant strain, which was unable to actively transport iron, to test whether this single gene deletion mutant (strain renamed GAP001) protected against an acute respiratory B...
September 28, 2017: Vaccines
https://www.readbyqxmd.com/read/28924168/investigation-of-a-spontaneous-mutant-reveals-novel-features-of-iron-uptake-in-shewanella-oneidensis
#7
Ziyang Dong, Shupan Guo, Huihui Fu, Haichun Gao
Shewanella oneidensis is among the first and the best studied bacteria capable of respiring minerals as terminal electron acceptors (EAs), including a variety of iron ores. This respiration process relies on a large number of c-type cytochromes, which per se are iron-containing proteins. Thus, iron plays an essential and special role in iron respiration of S. oneidensis, prompting extensive investigations into iron physiology. Despite this, we still know surprisingly little about the components and characteristics of iron transport in this bacterium...
September 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28900692/tonb-dependent-utilization-of-dihydroxamate-xenosiderophores-in-synechocystis-sp-pcc-6803
#8
Michael M Babykin, Tobias S A Obando, Vladislav V Zinchenko
In Gram-negative bacteria, transport of ferric siderophores through outer membrane is a complex process that requires specific outer membrane transporters and energy-transducing TonB-ExbB-ExbD system in the cytoplasmic membrane. The genome of the non-siderophore-producing cyanobacterium Synechocystis sp. PCC 6803 encodes all putative components of the siderophore-mediated iron uptake system. So far, there has been no experimental evidence for the existence of such a pathway in this organism. On the contrary, its reductive iron uptake pathway has been studied in detail...
September 12, 2017: Current Microbiology
https://www.readbyqxmd.com/read/28898501/growth-of-pseudomonas-aeruginosa-in-zinc-poor-environments-is-promoted-by-a-nicotianamine-related-metallophore
#9
Maria Chiara Mastropasqua, Melania D'Orazio, Mauro Cerasi, Francesca Pacello, Angelo Gismondi, Antonella Canini, Lorena Canuti, Ada Consalvo, Domenico Ciavardelli, Barbara Chirullo, Paolo Pasquali, Andrea Battistoni
Previous studies have suggested that P. aeruginosa possesses redundant zinc uptake systems. To identify uncharacterized zinc transporters, we analyzed the genome-wide transcriptional responses of P. aeruginosa PA14 to zinc restriction. This approach led to the identification of an operon (zrmABCD) regulated by the zinc uptake regulator Zur, that encodes for a metallophore-mediated zinc import system. This operon includes the genes for an uncharacterized TonB-dependent Outer Membrane Protein (ZrmA) and for a putative nicotianamine synthase (ZrmB)...
September 12, 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28893775/nosocomial-outbreak-of-extensively-drug-resistant-acinetobacter-baumannii-isolates-containing-blaoxa-237-carried-on-a-plasmid
#10
Andrea M Hujer, Paul G Higgins, Susan D Rudin, Genevieve L Buser, Steven H Marshall, Kyriaki Xanthopoulou, Harald Seifert, Laura J Rojas, T Nicholas Domitrovic, P Maureen Cassidy, Margaret C Cunningham, Robert Vega, Jon P Furuno, Christopher D Pfeiffer, Zintars G Beldavs, Meredith S Wright, Michael R Jacobs, Mark D Adams, Robert A Bonomo
Carbapenem antibiotics are among the mainstays for treating infections caused by Acinetobacter baumannii, especially in the Northwest United States, where carbapenem-resistant A. baumannii remains relatively rare. However, between June 2012 and October 2014, an outbreak of carbapenem-resistant A. baumannii occurred in 16 patients from five health care facilities in the state of Oregon. All isolates were defined as extensively drug resistant. Multilocus sequence typing revealed that the isolates belonged to sequence type 2 (international clone 2 [IC2]) and were >95% similar as determined by repetitive-sequence-based PCR analysis...
November 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28811613/transcriptomic-analysis-of-nickel-exposure-in-sphingobium-sp-ba1-cells-using-rna-seq
#11
M Volpicella, C Leoni, C Manzari, M Chiara, E Picardi, E Piancone, F Italiano, A D'Erchia, M Trotta, D S Horner, G Pesole, L R Ceci
Nickel acts as cofactor for a number of enzymes of many bacteria species. Its homeostasis is ensured by proteins working as ion efflux or accumulation systems. These mechanisms are also generally adopted to counteract life-threatening high extra-cellular Ni(2+) concentrations. Little is known regarding nickel tolerance in the genus Sphingobium. We studied the response of the novel Sphingobium sp. ba1 strain, able to adapt to high Ni(2+) concentrations. Differential gene expression in cells cultured in 10 mM Ni(2+), investigated by RNA-seq analysis, identified 118 differentially expressed genes...
August 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28713344/outer-membrane-proteome-of-veillonella-parvula-a-diderm-firmicute-of-the-human-microbiome
#12
Daniel I Poppleton, Magalie Duchateau, Véronique Hourdel, Mariette Matondo, Jennifer Flechsler, Andreas Klingl, Christophe Beloin, Simonetta Gribaldo
Veillonella parvula is a biofilm-forming commensal found in the lungs, vagina, mouth, and gastro-intestinal tract of humans, yet it may develop into an opportunistic pathogen. Furthermore, the presence of Veillonella has been associated with the development of a healthy immune system in infants. Veillonella belongs to the Negativicutes, a diverse clade of bacteria that represent an evolutionary enigma: they phylogenetically belong to Gram-positive (monoderm) Firmicutes yet maintain an outer membrane (OM) with lipopolysaccharide similar to classic Gram-negative (diderm) bacteria...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28698737/draft-genome-sequence-of-a-virulent-strain-of-pasteurella-multocida-isolated-from-alpaca
#13
Raquel Enma Hurtado, Flavia Aburjaile, Diego Mariano, Marcus Vinicius Canário, Leandro Benevides, Daniel Antonio Fernandez, Nataly Olivia Allasi, Rocio Rimac, Julio Eduardo Juscamayta, Jorge Enrique Maximiliano, Raul Hector Rosadio, Vasco Azevedo, Lenin Maturrano
Pasteurella multocida is one of the most frequently isolated bacteria in acute pneumonia cases, being responsible for high mortality rates in Peruvian young alpacas, with consequent social and economic costs. Here we report the genome sequence of P. multocida strain UNMSM, isolated from the lung of an alpaca diagnosed with pneumonia, in Peru. The genome consists of 2,439,814 base pairs assembled into 82 contigs and 2,252 protein encoding genes, revealing the presence of known virulence-associated genes (ompH, ompA, tonB, tbpA, nanA, nanB, nanH, sodA, sodC, plpB and toxA)...
2017: Journal of Genomics
https://www.readbyqxmd.com/read/28667620/assessing-energy-dependent-protein-conformational-changes-in-the-tonb-system
#14
Ray A Larsen
Changes in conformation can alter a protein's vulnerability to proteolysis. Thus, in vivo differential proteinase sensitivity provides a means for identifying conformational changes that mark discrete states in the activity cycle of a protein. The ability to detect a specific conformational state allows for experiments to address specific protein-protein interactions and other physiological components that potentially contribute to the function of the protein. This chapter presents the application of this technique to the TonB-dependent energy transduction system of Gram-negative bacteria, a strategy that has refined our understanding of how the TonB protein is coupled to the ion electrochemical gradient of the cytoplasmic membrane...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28627567/dissecting-binding-of-a-%C3%AE-barrel-membrane-protein-by-phage-display
#15
Luz M Meneghini, Sarvind Tripathi, Marcus A Woodworth, Sudipta Majumdar, Thomas L Poulos, Gregory A Weiss
Membrane proteins (MPs) constitute a third of all proteomes, and contribute to a myriad of cellular functions including intercellular communication, nutrient transport and energy generation. For example, TonB-dependent transporters (TBDTs) in the outer membrane of Gram-negative bacteria play an essential role transporting iron and other nutrients into the bacterial cell. The inherently hydrophobic surfaces of MPs complicates protein expression, purification, and characterization. Thus, dissecting the functional contributions of individual amino acids or structural features through mutagenesis can be a challenging ordeal...
July 25, 2017: Molecular BioSystems
https://www.readbyqxmd.com/read/28540303/identifying-the-genes-responsible-for-iron-limited-condition-in-riemerella-anatipestifer-ch-1-through-rna-seq-based-analysis
#16
MaFeng Liu, Mi Huang, DeKang Zhu, MingShu Wang, RenYong Jia, Shun Chen, KunFeng Sun, Qiao Yang, Ying Wu, Francis Biville, AnChun Cheng
One of the important elements for most bacterial growth is iron, the bioavailability of which is limited in hosts. Riemerella anatipestifer (R. anatipestifer, RA), an important duck pathogen, requires iron to live. However, the genes involved in iron metabolism and the mechanisms of iron transport are largely unknown. Here, we investigated the transcriptomic effects of iron limitation condition on R. anatipestifer CH-1 using the RNA-Seq and RNA-Seq-based analysis. Data analysis revealed genes encoding functions related to iron homeostasis, including a number of putative TonB-dependent receptor systems, a HmuY-like protein-dependent hemin (an iron-containing porphyrin) uptake system, a Feo system, a gene cluster related to starch utilization, and genes encoding hypothetical proteins that were significantly upregulated in response to iron limitation...
2017: BioMed Research International
https://www.readbyqxmd.com/read/28532667/evaluation-of-three-recombinant-outer-membrane-proteins-ompa1-tdr-and-tbpa-as-potential-vaccine-antigens-against-virulent-aeromonas-hydrophila-infection-in-channel-catfish-ictalurus-punctatus
#17
Hossam Abdelhamed, Iman Ibrahim, Seong Won Nho, Michelle M Banes, Robert W Wills, Attila Karsi, Mark L Lawrence
A virulent clonal population of Aeromonas hydrophila (VAh) is recognized as the etiological agent in outbreaks of motile aeromonas septicemia (MAS) in catfish aquaculture in the southeastern United States since 2009. Genomic subtraction revealed three outer membrane proteins present in VAh strain ML09-119 but not in low virulence reference A. hydrophila strains: major outer membrane protein OmpA1, TonB-dependent receptor (Tdr), and transferrin-binding protein A (TbpA). Here, the genes encoding ompA1, tdr, and tbpA were cloned from A...
May 19, 2017: Fish & Shellfish Immunology
https://www.readbyqxmd.com/read/28496441/discovery-of-novel-leptospirosis-vaccine-candidates-using-reverse-and-structural-vaccinology
#18
André Alex Grassmann, Frederico Schmitt Kremer, Júlia Cougo Dos Santos, Jéssica Dias Souza, Luciano da Silva Pinto, Alan John Alexander McBride
Leptospira spp. are diderm (two membranes) bacteria that infect mammals causing leptospirosis, a public health problem with global implications. Thousands of people die every year due to leptospirosis, especially in developing countries with tropical climates. Prophylaxis is difficult due to multiple factors, including the large number of asymptomatic hosts that transmit the bacteria, poor sanitation, increasing numbers of slum dwellers, and the lack of an effective vaccine. Several leptospiral recombinant antigens were evaluated as a replacement for the inactivated (bacterin) vaccine; however, success has been limited...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28487398/transition-metals-at-the-host-pathogen-interface-how-neisseria-exploit-human-metalloproteins-for-acquiring-iron-and-zinc
#19
REVIEW
Wilma Neumann, Rose C Hadley, Elizabeth M Nolan
Transition metals are essential nutrients for all organisms and important players in the host-microbe interaction. During bacterial infection, a tug-of-war between the host and microbe for nutrient metals occurs: the host innate immune system responds to the pathogen by reducing metal availability and the pathogen tries to outmaneuver this response. The outcome of this competition, which involves metal-sequestering host-defense proteins and microbial metal acquisition machinery, is an important determinant for whether infection occurs...
May 9, 2017: Essays in Biochemistry
https://www.readbyqxmd.com/read/28429713/gating-of-tonb-dependent-transporters-by-substrate-specific-forced-remodelling
#20
Samuel J Hickman, Rachael E M Cooper, Luca Bellucci, Emanuele Paci, David J Brockwell
Membrane proteins play vital roles in inside-out and outside-in signal transduction by responding to inputs that include mechanical stimuli. Mechanical gating may be mediated by the membrane or by protein(s) but evidence for the latter is scarce. Here we use force spectroscopy, protein engineering and bacterial growth assays to investigate the effects of force on complexes formed between TonB and TonB-dependent transporters (TBDT) from Gram-negative bacteria. We confirm the feasibility of protein-only mediated mechanical gating by demonstrating that the interaction between TonB and BtuB (a TBDT) is sufficiently strong under force to create a channel through the TBDT...
April 21, 2017: Nature Communications
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