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Cellular Microbiology

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https://www.readbyqxmd.com/read/29205773/treponema-denticola-increases-mmp-2-expression-and-activation-in-the-periodontium-via-reversible-dna-and-histone-modifications
#1
Islam M Ateia, Pimchanok Sutthiboonyapan, Pachiyappan Kamarajan, Taocong Jin, Valentina Godovikova, Yvonne L Kapila, J Christopher Fenno
Host-derived matrix metalloproteinases (MMPs) and bacterial proteases mediate destruction of extracellular matrices and supporting alveolar bone in periodontitis. The Treponema denticola dentilisin protease induces MMP-2 expression and activation in periodontal ligament (PDL) cells, and dentilisin-mediated activation of pro-MMP-2 is required for cellular fibronectin degradation. Here we report that T. denticola regulates MMP-2 expression through epigenetic modifications in the periodontium. PDL cells were treated with epigenetic enzyme inhibitors before or after T...
December 4, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29205766/the-bile-salt-sodium-taurocholate-induces-campylobacter-jejuni-outer-membrane-vesicle-production-and-increases-omv-associated-proteolytic-activity
#2
Abdi Elmi, Amber Dorey, Eleanor Watson, Heena Jagatia, Neil F Inglis, Ozan Gundogdu, Mona Bajaj-Elliott, Brendan W Wren, David G E Smith, Nick Dorrell
Campylobacter jejuni, the leading cause of bacterial acute gastroenteritis worldwide, secretes an arsenal of virulence-associated proteins within outer membrane vesicles (OMVs). C. jejuni OMVs contain three serine proteases (HtrA, Cj0511 and Cj1365c) which cleave the intestinal epithelial cell (IEC) tight and adherens junction proteins occludin and E-cadherin, promoting enhanced C. jejuni adhesion to and invasion of IECs. C. jejuni OMVs also induce IECs innate immune responses. The bile salt sodium taurocholate (ST) is sensed as a host signal to co-ordinate the activation of virulence-associated genes in the enteric pathogen Vibrio cholerae...
December 4, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29197141/the-human-blood-brain-barrier-internalizes-cryptococcus-neoformans-via-the-epha2-tyrosine-kinase-receptor
#3
Phylicia A Aaron, Mantana Jamklang, John P Uhrig, Angie Gelli
Cryptococcus neoformans is an opportunistic fungal pathogen that causes life-threatening meningitis most commonly in populations with impaired immunity. Here we resolved the transcriptome of the human brain endothelium challenged with C. neoformans to establish whether C. neoformans invades the CNS by co-opting particular signaling pathways as a means to promote its own entry. Among the 5 major pathways targeted by C. neoformans, the EPH-EphrinA1 (EphA2) tyrosine kinase receptor-signaling pathway was examined further...
December 2, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29168343/lipocalin-2-lcn2-interferes-with-iron-uptake-by-brucella-abortus-and-dampens-immunoregulation-during-infection-of-raw-264-7-macrophages
#4
Huynh Tan Hop, Lauren Togonon Arayan, Tran Xuan Ngoc Huy, Alisha Wehdnesday Bernardo Reyes, Eun Jin Baek, WonGi Min, Hu Jang Lee, Man Hee Rhee, Kenta Watanabe, Hong Hee Chang, Suk Kim
Lipocalin 2 (Lcn2) is an important innate immunity component against bacterial pathogens. In this study, we report that Lcn2 is induced by Brucella (B.) abortus infection and significantly contributes to the restriction of intracellular survival of Brucella in macrophages. We found that Lcn2 prevented iron uptake by B. abortus through two distinct mechanisms. First, Lcn2 is secreted to capture bacterial siderophore(s) and abrogate iron import by Brucella. Second, Lcn2 decreases the intracellular iron levels during Brucella infection, which probably deprives the invading Brucella of the iron source needed for growth...
November 22, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29156489/an-adherent-mucus-layer-attenuates-the-genotoxic-effect-of-colibactin
#5
Christian Reuter, Mona Alzheimer, Heike Walles, Tobias A Oelschlaeger
The human gastrointestinal tract is a complex ecosystem in which epithelial cells and microorganisms of the intestinal microbiota live in symbiosis. Certain members of the microbiota, in particular Escherichia coli strains of the B2 phylotype, carry the polyketide synthase (pks)-island encoding the genotoxin colibactin. Colibactin is a non-ribosomal peptide (NRP) or polyketide (PK)-NRP hybrid of still unsolved structure, which induces DNA double strand breaks (DSBs) in eukaryotic cells. However, direct contact between live bacteria and host cell is required in order to elicit these genotoxic effects...
November 20, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29155483/modeling-persistent-mycoplasma-pneumoniae-infection-of-human-airway-epithelium
#6
Oliver A Prince, Thomas M Krunkosky, Edward S Sheppard, Duncan C Krause
Mycoplasma pneumoniae is a human respiratory tract pathogen causing acute and chronic airway disease states that can include long-term carriage and extra-pulmonary spread. The mechanisms of persistence and migration beyond the conducting airways, however, remain poorly understood. We previously described an acute exposure model using normal human bronchial epithelium (NHBE) in air-liquid interface culture, showing that M. pneumoniae gliding motility is essential for initial colonization and subsequent spread, including localization to epithelial cell junctions...
November 20, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29125705/m-tuberculosis-mce3c-promotes-mycobacteria-entry-into-macrophages-through-activation-of-%C3%AE-2-integrin-mediated-signaling-pathway
#7
Yong Zhang, Jie Li, Bingxi Li, Jing Wang, Cui Hua Liu
Establishment of infection by facultative intracellular pathogen Mycobacterium tuberculosis (Mtb) requires adherence to and internalization by macrophages. However, the effector molecules exploited by Mtb for entry into macrophages remain to be fully understood. The mammalian cell entry (Mce) proteins play an essential role in facilitating the internalization of mycobacteria into mammalian cells. Here we characterized Mtb Mce3C as a new mycobacterial surface protein that could promote mycobacterial adhesion to and invasion of macrophages in an RGD motif-dependent manner...
November 10, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29119662/toxoplasma-gondii-infection-shifts-dendritic-cells-into-an-amoeboid-rapid-migration-mode-encompassing-podosome-dissolution-secretion-of-timp-1-and-reduced-proteolysis-of-extracellular-matrix
#8
Einar B Ólafsson, Manuel Varas-Godoy, Antonio Barragan
Dendritic cells (DCs) infected by Toxoplasma gondii rapidly acquire a hypermigratory phenotype that promotes systemic parasite dissemination by a 'Trojan horse' mechanism in mice. Recent paradigms of leukocyte migration have identified the amoeboid migration mode of DCs as particularly suited for rapid locomotion in extracellular matrix and tissues. Here, we have developed a microscopy-based high-throughput approach to assess motility and matrix degradation by Toxoplasma-challenged murine and human DCs. DCs challenged with T...
November 8, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29119655/targeting-host-mitochondria-a-role-for-the-trypanosoma-cruzi-amastigote-flagellum
#9
Gaelle Lentini, Nicolas Dos Santos Pacheco, Barbara A Burleigh
Trypanosoma cruzi is the kinetoplastid protozoan parasite that causes human Chagas disease, a chronic disease with complex outcomes including severe cardiomyopathy and sudden death. In mammalian hosts, T. cruzi colonizes a wide range of tissues and cell types where it replicates within the host cell cytoplasm. Like all intracellular pathogens, T. cruzi amastigotes must interact with its immediate host cell environment in a manner that facilitates access to nutrients and promotes a suitable niche for replication and survival...
November 8, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29117636/chlamydia-trachomatis-regulates-growth-and-development-in-response-to-host-cell-fatty-acid-availability-in-the-absence-of-lipid-droplets
#10
Manu Sharma, Maria A Recuero-Checa, Francis Yue Fan, Deborah Dean
Chlamydia trachomatis (Ct) is a Gram-negative obligate intracellular pathogen of humans that causes significant morbidity from sexually transmitted and ocular diseases globally. Ct acquires host fatty acids (FA) to meet the metabolic and growth requirements of the organism. Lipid droplets (LDs) are storehouses of FAs in host cells and have been proposed to be a source of FAs for the parasitophorous vacuole, termed inclusion, in which Ct replicates. Previously, cells devoid of LDs were shown to produce reduced infectious progeny at 24 hours post-infection (hpi)...
November 8, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29114981/ptab-a-lim-domain-binding-protein-in-aspergillus-fumigatus-regulates-biofilm-formation-and-conidiation-through-distinct-pathways
#11
Shizhu Zhang, Yuan Chen, Zhihua Ma, Qiuyi Chen, Hanna Ostapska, Fabrice N Gravelat, Ling Lu, Donald C Sheppard
The exopolysaccharide galactosaminogalactan (GAG) plays an important role in mediating adhesion, biofilm formation and virulence in the pathogenic fungus Aspergillus fumigatus. The developmental modifiers MedA, StuA and SomA regulate GAG biosynthesis, but the mechanisms underlying this regulation are poorly understood. PtaB is a lim-domain binding protein that interacts with the transcription factor SomA and is required for normal conidiation and biofilm formation. Disruption of ptaB resulted in impaired GAG production and conidiation in association with a markedly reduced expression of GAG biosynthetic genes (uge3 and agd3), developmental regulators (medA and stuA), and genes involved in the core conidiation pathway...
November 7, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29113016/cryptococcal-dissemination-to-the-central-nervous-system-requires-the-vacuolar-calcium-transporter-pmc1
#12
Eamim D Squizani, Natália K Oliveira, Júlia C V Reuwsaat, Bárbara M Marques, William Lopes, Alexandra L Gerber, Ana Tereza R de Vasconcelos, Sophie Lev, Julianne T Djordjevic, Augusto Schrank, Marilene H Vainstein, Charley C Staats, Lívia Kmetzsch
Cryptococcus neoformans is a basidiomycetous yeast and the cause of cryptococcosis in immunocompromised individuals. The most severe form of the disease is meningoencephalitis, which is one of the leading cause of death in HIV/AIDS patients. In order to access the central nervous system (CNS), C. neoformans relies on the activity of certain virulence factors such as urease, which allows transmigration through the blood-brain barrier (BBB). In the present study, we demonstrate that the calcium transporter Pmc1 enables C...
November 7, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29113011/aspergillus-fumigatus-adhesion-factors-in-dormant-conidia-revealed-through-comparative-phenotypic-and-transcriptomic-analyses
#13
Azusa Takahashi-Nakaguchi, Kanae Sakai, Hiroki Takahashi, Daisuke Hagiwara, Takahito Toyotome, Hiroji Chibana, Akira Watanabe, Takashi Yaguchi, Masashi Yamaguchi, Katsuhiko Kamei, Tohru Gonoi
Aspergillus fumigatus is an important fungal pathogen of humans. Inhaled conidia of A. fumigatus adhere to pulmonary epithelial cells, causing oportunistic infection. However, little is known about the molecular mechanism of the adherence of resting conidia. Fungal molecules adhesive to host cells are presumed to be displayed on the conidial surface during conidial formation as a result of changes in gene expression. Therefore, we exhaustively searched for adhesion molecules by comparing the phenotypes and the gene expression profiles of A...
November 7, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29112323/identification-of-gbf1-as-a-cellular-factor-required-for-hepatitis-e-virus-rna-replication
#14
Rayan Farhat, Maliki Ankavay, Nadjet Lebsir, Jérôme Gouttenoire, Catherine L Jackson, Czeslaw Wychowski, Darius Moradpour, Jean Dubuisson, Yves Rouille, Laurence Cocquerel
The hepatitis E virus (HEV) genome is a single-stranded, positive-sense RNA that encodes three proteins including the ORF1 replicase. Mechanisms of HEV replication in host cells are unclear and only a few cellular factors involved in this step have been identified so far. Here, we used brefeldin A (BFA) that blocks the activity of the cellular Arf guanine nucleotide exchange factors GBF1, BIG1 and BIG2, which play a major role in reshuffling of cellular membranes. We showed that BFA inhibits HEV replication in a dose-dependent manner...
November 7, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29112299/activation-of-lpxr-gene-through-enterohemorrhagic-escherichia-coli-virulence-regulators-mediates-lipid-a-modification-to-attenuate-innate-immune-response
#15
Rikako Ogawa, Hilo Yen, Kiyoshi Kawasaki, Toru Tobe
During the course of infection, pathogens must overcome a variety of host defense systems. Modulation of lipid A, which is a strong stimulant for host immune systems, is one of the strategies used by microorganisms to evade the host response. The lpxR gene, which encodes a lipid A 3'-O-deacylase, is commonly found in several pathogens and has been shown to reduce the inflammatory response. Here, we demonstrated that the lpxR gene of enterohemorrhagic E. coli (EHEC) was positively regulated by two virulence regulators, Pch and Ler, and that this regulation was coordinated with the LEE genes, which encode major virulence factors for colonization...
November 7, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29112296/live-faecalibacterium-prausnitzii-induces-greater-tlr2-and-tlr2-6-activation-than-the-dead-bacterium-in-an-apical-anaerobic-co-culture-system
#16
Eva Maier, Rachel C Anderson, Eric Altermann, Nicole C Roy
Inappropriate activation of intestinal innate immune receptors, such as Toll-like receptors (TLRs), by pathogenic bacteria is linked to chronic inflammation. In contrast, a 'tonic' level of TLR activation by commensal bacteria is required for intestinal homeostasis. A technical challenge when studying this activation in vitro is the co-culturing of oxygen-requiring mammalian cells with obligate anaerobic commensal bacteria. To overcome this, we used a novel apical anaerobic co-culture system to successfully adapt a TLR activation assay to be conducted in conditions optimised for both cell types...
November 7, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29088499/neutrophils-differentially-attenuate-immune-response-to-aspergillus-infection-through-complement-receptor-3-and-induction-of-myeloperoxidase
#17
Jessamine G Goh, Sharada Ravikumar, Mar Soe Win, Qiong Cao, Ai Ling Tan, Joan H J Lim, Winnie Leong, Raoul Herbrecht, Peter F Troke, Bart Jan Kullberg, Mihai G Netea, Wee Joo Chng, Yock Young Dan, Louis Y A Chai
Invasive aspergillosis (IA) remains a major cause of morbidity in immunocompromised hosts. This is due to the inability of the host immunity to respond appropriately to Aspergillus. An established risk factor for IA is neutropenia which is encountered by patients undergoing chemotherapy. Herein we investigate the role of neutrophils in modulating host response to Aspergillus. We found that neutrophils had the propensity to suppress proinflammatory cytokine production but through different mechanisms for specific cytokines...
October 31, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29087624/tracking-elusive-cargo-illuminating-spatio-temporal-type-3-effector-protein-dynamics-using-reporters
#18
REVIEW
Nicky O'Boyle, James P R Connolly, Andrew J Roe
Type 3 secretion systems (T3SS) form an integral part of the arsenal of many pathogenic bacteria. These injection machines, together with their cargo of subversive effector proteins are capable of manipulating the cellular environment of the host in order to ensure persistence of the pathogen. In order to fully appreciate the functions of Type 3 effectors it is necessary to gain spatio-temporal knowledge of each effector during the process of infection. A number of genetic modifications have been exploited in order to reveal effector protein secretion, translocation and subsequent activity and localisation within host cells...
October 31, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29084417/proteomics-analysis-of-medicago-truncatula-response-to-infection-by-the-phytopathogenic-bacterium-ralstonia-solanacearum-points-to-jasmonate-and-salicylate-defence-pathways
#19
Ahad Yamchi
The infection of the model legume Medicago truncatula with Ralstonia solanacearum GMI1000 gives rise to bacterial wilt disease via colonization of roots. The root and leaf responses to early infection (one and three days post infection) were characterized to investigate the molecular mechanisms of plant resistance or susceptibility. A proteomics approach based on pools of susceptible and resistant recombinant inbred lines was used to specifically target the mechanisms for tolerance. Differential abundances were evidenced for proteins involved in defense (e...
October 30, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/29063667/bacterial-lipoproteins-and-other-factors-released-by-francisella-tularensis-modulate-human-neutrophil-lifespan-effects-of-a-tlr1-snp-on-apoptosis-inhibition
#20
Lauren C Kinkead, Laura C Whitmore, Jenna M McCracken, Joshua R Fletcher, Brandi B Ketelsen, Justin W Kaufman, Bradley D Jones, David S Weiss, Jason H Barker, Lee-Ann H Allen
F. tularensis infects several cell types including neutrophils, and aberrant neutrophil accumulation contributes to tissue destruction during tularemia. We demonstrated previously that F. tularensis strains Schu S4 and LVS markedly delay human neutrophil apoptosis and thereby prolong cell lifespan, but the bacterial factors that mediate this aspect of virulence are undefined. Herein, we demonstrate that bacterial conditioned medium (CM) can delay apoptosis in the absence of direct infection. Biochemical analyses show that CM contained F...
October 23, 2017: Cellular Microbiology
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