Read by QxMD icon Read


Dmitry Ratner, M Pontus A Orning, Megan K Proulx, Donghai Wang, Mikhail A Gavrilin, Mark D Wewers, Emad S Alnemri, Peter F Johnson, Bettina Lee, Joan Mecsas, Nobuhiko Kayagaki, Jon D Goguen, Egil Lien
Type III secretion systems (T3SS) are central virulence factors for many pathogenic Gram-negative bacteria, and secreted T3SS effectors can block key aspects of host cell signaling. To counter this, innate immune responses can also sense some T3SS components to initiate anti-bacterial mechanisms. The Yersinia pestis T3SS is particularly effective and sophisticated in manipulating the production of pro-inflammatory cytokines IL-1β and IL-18, which are typically processed into their mature forms by active caspase-1 following inflammasome formation...
December 2016: PLoS Pathogens
Kuan-Yeh Huang, Yi-Hsin Wang, Kun-Yi Chien, Rajendra Prasad Janapatla, Cheng-Hsun Chiu
Salmonella enterica serovars Choleraesuis and Typhimurium are among the non-typhoid Salmonella serovars that are important zoonotic pathogens. In clinical observation, S. Typhimurium typically causes diarrheal diseases; however, S. Choleraesuis shows high predilection to cause bacteremia. The mechanism why S. Choleraesuis is more invasive to humans remains unknown. In this study, we compared the S. Typhimurium LT2 and S. Choleraesuis SC-B67 proteomes through stable isotope labeling of amino acid in cell culture (SILAC)...
November 25, 2016: Scientific Reports
Natalia Amigo, Qi Zhang, Ariel Amadio, Qunjie Zhang, Wanderson M Silva, Baiyuan Cui, Zhongjian Chen, Mariano Larzabal, Jinlong Bei, Angel Cataldi
Escherichia coli O157:H7 is responsible for severe diarrhea and hemolytic uremic syndrome (HUS), and predominantly affects children under 5 years. The major virulence traits are Shiga toxins, necessary to develop HUS and the Type III Secretion System (T3SS) through which bacteria translocate effector proteins directly into the host cell. By SNPs typing, E. coli O157:H7 was separated into nine different clades. Clade 8 and clade 6 strains were more frequently associated with severe disease and HUS. In this study, we aimed to identify differentially expressed proteins in two strains of E...
2016: PloS One
Kimberly M Carlson-Banning, Vanessa Sperandio
: The biogeography of the gut is diverse in its longitudinal axis, as well as within specific microenvironments. Differential oxygenation and nutrient composition drive the membership of microbial communities in these habitats. Moreover, enteric pathogens can orchestrate further modifications to gain a competitive advantage toward host colonization. These pathogens are versatile and adept when exploiting the human colon. They expertly navigate complex environmental cues and interkingdom signaling to colonize and infect their hosts...
November 22, 2016: MBio
Kristina Creuzburg, Cristina Giogha, Tania Wong Fok Lung, Nichollas E Scott, Sabrina Mühlen, Elizabeth L Hartland, Jaclyn S Pearson
Enteropathogenic Escherichia coli (EPEC) is a gastrointestinal pathogen that utilises a type III secretion system (T3SS) to inject an array of virulence effector proteins into host enterocytes to subvert numerous cellular processes for successful colonisation and dissemination. The T3SS effector NleD is a 28 kDa zinc metalloprotease that is translocated into host enterocytes where it directly cleaves and inactivates the MAP kinase signaling proteins, JNK and p38. Here a library of 91 random transposon based, in-frame, linker insertion mutants of NleD were tested for their ability to cleave JNK and p38 during transient transfection of cultured epithelial cells...
November 21, 2016: Infection and Immunity
Veronica Ancona, Jae Hoon Lee, Youfu Zhao
The GacS/GacA two-component system (also called GrrS/GrrA) is a global regulatory system which is highly conserved among gamma-proteobacteria. This system positively regulates non-coding small regulatory RNA csrB, which in turn binds to the RNA-binding protein CsrA. However, how GacS/GacA-Csr system regulates virulence traits in E. amylovora remains unknown. Results from mutant characterization showed that the csrB mutant was hypermotile, produced higher amount of exopolysaccharide amylovoran, and had increased expression of type III secretion (T3SS) genes in vitro...
November 15, 2016: Scientific Reports
Danielle L Jessen Condry, Matthew L Nilles
A type III secretion system (T3SS) Inhibitor can be utilized for study in the research lab but also progressed into drug development. Since many pathogenic Gram-negative bacteria utilize this highly conserved system as a virulence factor, the prospect of the T3SS as a drug target is promising. To effectively move a T3SS inhibitor into the route of either research or pharmaceuticals an understanding of the target and mechanism of the inhibitor is required. Several methods can be utilized to identify the target...
2017: Methods in Molecular Biology
Travis D Alvine, Patrick Osei-Owusu, Danielle L Jessen Condry, Matthew L Nilles
The ability to express and purify recombinant needle proteins from the Type III Secretion System (T3SS) of many gram-negative bacteria has allowed us to develop novel experimental approaches, both in vitro and in vivo, to identify unique roles for T3SS in bacterial pathogenesis. In addition, these purified needle proteins have shown to be promising immunotherapies acting as both protective antigens and adjuvants, presumably due to their immune activating properties. Here, we describe the expression and purification of recombinant T3SS needle proteins...
2017: Methods in Molecular Biology
Michael L Barta, Philip R Adam, Nicholas E Dickenson
Type III secretion systems (T3SS) are highly conserved virulence factors employed by a large number of pathogenic gram-negative bacteria. Like many T3SS translocators, recombinant expression of the hydrophobic Shigella protein IpaB requires the presence of its cognate chaperone IpgC. Chaperone-bound IpaB is maintained in a nonfunctional state, which has hampered in vitro studies aimed at understanding molecular structure and function of this important class of T3SS proteins. Herein, we describe an expression and purification protocol that utilizes mild detergents to produce highly purified, homogeneous IpaB of defined oligomeric states...
2017: Methods in Molecular Biology
Rachel M Olson, Deborah M Anderson
Many Gram-negative bacterial pathogens use type III secretion systems to export proteins that act directly on the host and aid in the infectious process. Extracellular bacteria primarily rely upon the type III secretion system to insert or inject effector proteins into the cytosol of their host cell in order to perturb intracellular signaling events and aid in pathogenesis. Intracellular bacteria can also depend on the T3SS translocation of effector proteins from vacuolar compartments into the vacuolar membrane or host cell cytosol where they can modulate intracellular trafficking and/or signaling pathways necessary for their growth and survival...
2017: Methods in Molecular Biology
Danielle L Jessen Condry, Matthew L Nilles
Secreted proteins of the T3SS vary from genus to genus. How secretion is induced in vitro also depends on the genus of bacteria. However, once those proteins are isolated the method for analyzing those proteins is largely the same. The following chapter outlines the specific induction of Yersinia secreted proteins and uniform analysis of those secreted proteins.
2017: Methods in Molecular Biology
Philip R Adam, Michael L Barta, Nicholas E Dickenson
In vitro characterization of type III secretion system (T3SS) translocator proteins has proven challenging due to complex purification schemes and their hydrophobic nature that often requires detergents to provide protein solubility and stability. Here, we provide experimental details for several techniques that overcome these hurdles, allowing for the direct characterization of the Shigella translocator protein IpaB with respect to phospholipid membrane interaction. The techniques specifically discussed in this chapter include membrane interaction/liposome flotation, liposome sensitive fluorescence quenching, and protein-mediated liposome disruption assays...
2017: Methods in Molecular Biology
Thomas A Henderson, Matthew L Nilles
Since the introduction of blue native, clear native, and high-resolution clear native electrophoresis to study protein complexes of eukaryotic, bacterial, and archaeal cells, the technique has been used primarily to study physiological systems that are found in abundance within the cell. Systems involved in oxidative phosphorylation, electron transport, membrane transporters, and secretion systems have been studied using these techniques. These microscale techniques are ideal due to the minimal perturbations caused to these protein complexes...
2017: Methods in Molecular Biology
Matthew S Francis, Ayad A A Amer, Debra L Milton, Tiago R D Costa
Type III secretion systems are a prolific virulence determinant among Gram-negative bacteria. They are used to paralyze the host cell, which enables bacterial pathogens to establish often fatal infections-unless an effective therapeutic intervention is available. However, as a result of a catastrophic rise in infectious bacteria resistant to conventional antibiotics, these bacteria are again a leading cause of worldwide mortality. Hence, this report describes a pDM4-based site-directed mutagenesis strategy that is assisting in our foremost objective to better understand the fundamental workings of the T3SS, using Yersinia as a model pathogenic bacterium...
2017: Methods in Molecular Biology
Ethel Bayer-Santos, Charlotte H Durkin, Luciano A Rigano, Andreas Kupz, Eric Alix, Ondrej Cerny, Elliott Jennings, Mei Liu, Aindrias S Ryan, Nicolas Lapaque, Stefan H E Kaufmann, David W Holden
The SPI-2 type III secretion system (T3SS) of intracellular Salmonella enterica translocates effector proteins into mammalian cells. Infection of antigen-presenting cells results in SPI-2 T3SS-dependent ubiquitination and reduction of surface-localized mature MHC class II (mMHCII). We identify the effector SteD as required and sufficient for this process. In Mel Juso cells, SteD localized to the Golgi network and vesicles containing the E3 ubiquitin ligase MARCH8 and mMHCII. SteD caused MARCH8-dependent ubiquitination and depletion of surface mMHCII...
November 9, 2016: Cell Host & Microbe
Rishikesh Kumar, Madhvi Soni, Kalyan K Mondal
Bacterial blight caused by Xanthomonas axonopodis pv. punicae (Xap) is a major disease of pomegranate. Xap secretes effector proteins via type III secretion system (T3SS) to suppress pathogen-associated molecular pattern (PAMP)-triggered plant immunity (PTI). Previously we reported that XopN, a conserved effector of Xap, modulate in planta bacterial growth, and blight disease. In continuation to that here we report the deletion of XopN from Xap caused higher accumulation of reactive oxygen species (ROS) including H2O2 and O2(-)...
December 2016: Microbiological Research
Meztlli O Gaytán, Verónica I Martínez-Santos, Eduardo Soto, Bertha González-Pedrajo
Enteropathogenic Escherichia coli and enterohemorrhagic E. coli are diarrheagenic bacterial human pathogens that cause severe gastroenteritis. These enteric pathotypes, together with the mouse pathogen Citrobacter rodentium, belong to the family of attaching and effacing pathogens that form a distinctive histological lesion in the intestinal epithelium. The virulence of these bacteria depends on a type III secretion system (T3SS), which mediates the translocation of effector proteins from the bacterial cytosol into the infected cells...
2016: Frontiers in Cellular and Infection Microbiology
Dmitry Ratner, M Pontus A Orning, Egil Lien
Innate immunity is critical for host defenses against pathogens, but many bacteria display complex ways of interacting with innate immune signaling, as they may both activate and evade certain pathways. Gram-negative bacteria can exhibit specialized nanomachine secretion systems for delivery of effector proteins into mammalian cells. Bacterial types III, IV, and VI secretion systems (T3SS, T4SS, and T6SS) are known for their impact on caspase-1-activating inflammasomes, necessary for producing bioactive inflammatory cytokines IL-1β and IL-18, key participants of anti-bacterial responses...
November 3, 2016: Journal of Leukocyte Biology
Jennifer Chua, Jeffrey L Senft, Stephen J Lockett, Paul J Brett, Mary N Burtnick, David DeShazer, Arthur M Friedlander
Burkholderia mallei and B. pseudomallei cause glanders and melioidosis, respectively, in humans and animals. A hallmark of pathogenesis is formation of granulomas containing multi-nucleated giant cells (MNGCs) and cell death. These processes depend on the Type 6 secretion system-1 (T6SS-1), which is required for virulence in animals. We examined the cell biology of MNGC formation and cell death. We found that chloroquine (CLQ), an anti-malarial drug, inhibits Burkholderia growth, phagosomal escape and subsequent MNGC formation...
October 31, 2016: Infection and Immunity
Xiaonan Zhuang, Zijuan Chen, Chenxi He, Lin Wang, Ruixue Zhou, Dapeng Yan, Baoxue Ge
To successfully infect host cells and evade the host immune response, a type III secretion system (T3SS) is commonly used by enteric bacterial pathogens such as enteropathogenic Escherichia coli (EPEC). Recent findings have revealed that various effectors are injected into host cells through the T3SS and exert an inhibitory effect on inflammatory signaling pathways, subverting the immune responses to these pathogens. Here we review recent studies aimed at addressing the modulation of several important inflammatory signaling pathways modulated by EPEC effector proteins, such as the nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways, which provides insight into the unfinished work in this unexplored field and helps to identify novel positions in inflammatory signaling networks for EPEC effectors...
October 31, 2016: Cellular & Molecular Immunology
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"