scholarly journals Laser scanning cytometer-based assays for measuring host cell attachment and invasion by the human pathogenToxoplasma gondii

2005 ◽  
Vol 69A (1) ◽  
pp. 13-19 ◽  
Author(s):  
Jeffrey Mital ◽  
Janet Schwarz ◽  
Douglas J. Taatjes ◽  
Gary E. Ward
Keyword(s):  
Host Cell ◽  
Laser Scanning ◽  
Cell Attachment ◽  
Host Cell Attachment ◽  
Laser Scanning Cytometer

scholarly journals A structure-based rationale for sialic acid independent host-cell entry of Sosuga virus

2019 ◽  
Vol 116 (43) ◽  
pp. 21514-21520 ◽  
Author(s):  
Alice J. Stelfox ◽  
Thomas A. Bowden
Keyword(s):  
Sialic Acid ◽  
Host Cell ◽  
Receptor Binding ◽  
Cell Attachment ◽  
Cell Entry ◽  
Head Region ◽  
Close Proximity ◽  
Host Cell Attachment ◽  
Host Cell Entry

The bat-borne paramyxovirus, Sosuga virus (SosV), is one of many paramyxoviruses recently identified and classified within the newly established genus Pararubulavirus, family Paramyxoviridae. The envelope surface of SosV presents a receptor-binding protein (RBP), SosV-RBP, which facilitates host-cell attachment and entry. Unlike closely related hemagglutinin neuraminidase RBPs from other genera of the Paramyxoviridae, SosV-RBP and other pararubulavirus RBPs lack many of the stringently conserved residues required for sialic acid recognition and hydrolysis. We determined the crystal structure of the globular head region of SosV-RBP, revealing that while the glycoprotein presents a classical paramyxoviral six-bladed β-propeller fold and structurally classifies in close proximity to paramyxoviral RBPs with hemagglutinin-neuraminidase (HN) functionality, it presents a receptor-binding face incongruent with sialic acid recognition. Hemadsorption and neuraminidase activity analysis confirms the limited capacity of SosV-RBP to interact with sialic acid in vitro and indicates that SosV-RBP undergoes a nonclassical route of host-cell entry. The close overall structural conservation of SosV-RBP with other classical HN RBPs supports a model by which pararubulaviruses only recently diverged from sialic acid binding functionality.

scholarly journals Complementation of the fadA Mutation in Fusobacterium nucleatum Demonstrates that the Surface-Exposed Adhesin Promotes Cellular Invasion and Placental Colonization

2009 ◽  
Vol 77 (7) ◽  
pp. 3075-3079 ◽  
Author(s):  
Akihiko Ikegami ◽  
Peter Chung ◽  
Yiping W. Han
Keyword(s):  
Host Cell ◽  
Cell Attachment ◽  
Adverse Pregnancy Outcome ◽  
Fusobacterium Nucleatum ◽  
Host Cells ◽  
Mouse Placenta ◽  
Host Cell Attachment ◽  
Adverse Pregnancy

ABSTRACT Fusobacterium nucleatum is a gram-negative oral anaerobe implicated in periodontal disease and adverse pregnancy outcome. The organism colonizes the mouse placenta, causing localized infection and inflammation. The mechanism of placental colonization has not been elucidated. Previous studies identified a novel adhesin from F. nucleatum, FadA, as being involved in the attachment and invasion of host cells. The fadA deletion mutant F. nucleatum 12230 US1 was defective in host cell attachment and invasion in vitro, but it also exhibited pleiotropic effects with altered cell morphology and growth rate. In this study, a fadA-complementing clone, F. nucleatum 12230 USF81, was constructed. The expression of FadA on USF81 was confirmed by Western blotting and immunofluorescent labeling. USF81 restored host cell attachment and invasion activities. The ability of F. nucleatum 12230, US1, and USF81 to colonize the mouse placenta was examined. US1 was severely defective in placental colonization compared to the wild type and USF81. Thus, FadA plays an important role in F. nucleatum colonization in vivo. These results also represent the first complementation studies for F. nucleatum. FadA may be a therapeutic target for preventing F. nucleatum colonization of the host.

scholarly journals The autotransporter protein from Bordetella avium, Baa1, is involved in host cell attachment

2011 ◽  
Vol 167 (1) ◽  
pp. 55-60 ◽  
Author(s):  
S.B. Stockwell ◽  
H. Kuzmiak-Ngiam ◽  
N.M. Beach ◽  
D. Miyamoto ◽  
R. Fernandez ◽  
...  
Keyword(s):  
Host Cell ◽  
Cell Attachment ◽  
Bordetella Avium ◽  
Host Cell Attachment

scholarly journals Monocyte-derived chicken macrophages exposed to Eimeria tenella sporozoites display reduced susceptibility to invasion by Toxoplasma gondii tachyzoites

2020 ◽  
Author(s):  
Runhui Zhang ◽  
Wanpeng Zheng ◽  
Arwid Daugschies ◽  
Berit Bangoura
Keyword(s):  
Host Cell ◽  
Cell Invasion ◽  
Cell Attachment ◽  
Gliding Motility ◽  
Phagocytic Cells ◽  
Apicomplexan Parasites ◽  
Cell Responses ◽  
Host Cell Attachment ◽  
Parasite Replication ◽  
Host Parasite

Abstract Background: Both Eimeria (E.) tenella and Toxoplasma (T.) gondii are common apicomplexan parasites in chickens. Host cell invasion by both protozoans includes gliding motility, host cell attachment and active penetration. Chicken macrophages as phagocytic cells participate in the innate host immune response against these two parasites. Methods: In this study, primary chicken monocyte-derived macrophages (MMs) were infected with both pathogens to investigate mutual and host-parasite interactions. MMs cultures were assigned to groups that were infected with E. tenella, T. gondii, or both. In co-infected cultures, MMs were first exposed to E. tenella sporozoites for 2 hours. Afterwards, T. gondii tachyzoite infection was performed. Live-cell imaging was carried out to observe cell invasion and survival of T. gondii by single parasite tracking over a period of 20 hours post infection (hpi). Quantitative analysis for parasite replication was performed at 2, 6, 12 and 24 hpi by real-time PCR (qPCR).Results: We found that during early co-infection T. gondii tachyzoites adhered for more than 4 hours to macrophages. Although they displayed high motility, ability to penetrate the cell membrane of the potential host cell was reduced. qPCR results confirmed that significantly less T. gondii entered E. tenella-activated MMs at 2 hpi, and a reduced proportion of intracellular T. gondii survived and replicated in these cells at 24 hpi. Conclusions: We conclude that E. tenella modulates host cell responses to another apicomplexan agent, T. gondii, reducing active invasion and multiplication in chicken primary macrophages.

scholarly journals Reovirus σ1 Conformational Flexibility Modulates the Efficiency of Host Cell Attachment

2020 ◽  
Vol 94 (23) ◽  
Author(s):  
Julia R. Diller ◽  
Sean R. Halloran ◽  
Melanie Koehler ◽  
Rita dos Santos Natividade ◽  
David Alsteens ◽  
...  
Keyword(s):  
Host Cell ◽  
Receptor Binding ◽  
Cell Attachment ◽  
Conformational Flexibility ◽  
Parental Virus ◽  
Receptor Binding Domain ◽  
Cross Link ◽  
Attachment Protein ◽  
Host Cell Attachment ◽  
Conformational Rearrangements

ABSTRACT Reovirus attachment protein σ1 is a trimeric molecule containing tail, body, and head domains. During infection, σ1 engages sialylated glycans and junctional adhesion molecule-A (JAM-A), triggering uptake into the endocytic compartment, where virions are proteolytically converted to infectious subvirion particles (ISVPs). Further disassembly allows σ1 release and escape of transcriptionally active reovirus cores into the cytosol. Electron microscopy has revealed a distinct conformational change in σ1 from a compact form on virions to an extended form on ISVPs. To determine the importance of σ1 conformational mobility, we used reverse genetics to introduce cysteine mutations that can cross-link σ1 by establishing disulfide bonds between structurally adjacent sites in the tail, body, and head domains. We detected phenotypic differences among the engineered viruses. A mutant with a cysteine pair in the head domain replicates with enhanced kinetics, forms large plaques, and displays increased avidity for JAM-A relative to the parental virus, mimicking properties of ISVPs. However, unlike ISVPs, particles containing cysteine mutations that cross-link the head domain uncoat and transcribe viral positive-sense RNA with kinetics similar to the parental virus and are sensitive to ammonium chloride, which blocks virion-to-ISVP conversion. Together, these data suggest that σ1 conformational flexibility modulates the efficiency of reovirus host cell attachment. IMPORTANCE Nonenveloped virus entry is an incompletely understood process. For reovirus, the functional significance of conformational rearrangements in the attachment protein, σ1, that occur during entry and particle uncoating are unknown. We engineered and characterized reoviruses containing cysteine mutations that cross-link σ1 monomers in nonreducing conditions. We found that the introduction of a cysteine pair in the receptor-binding domain of σ1 yielded a virus that replicates with faster kinetics than the parental virus and forms larger plaques. Using functional assays, we found that cross-linking the σ1 receptor-binding domain modulates reovirus attachment but not uncoating or transcription. These data suggest that σ1 conformational rearrangements mediate the efficiency of reovirus host cell binding.

scholarly journals Structure-based discovery of a small-molecule inhibitor of methicillin-resistant Staphylococcus aureus virulence

2020 ◽  
Vol 295 (18) ◽  
pp. 5944-5959 ◽  
Author(s):  
Jie Liu ◽  
Lina Kozhaya ◽  
Victor J. Torres ◽  
Derya Unutmaz ◽  
Min Lu
Keyword(s):  
Staphylococcus Aureus ◽  
Host Cell ◽  
Cell Attachment ◽  
Host Cell Membrane ◽  
Methicillin Resistant ◽  
Molecule Inhibitor ◽  
Membrane Perforation ◽  
Host Cell Attachment ◽  
Mrsa Strains

The rapid emergence and dissemination of methicillin-resistant Staphylococcus aureus (MRSA) strains poses a major threat to public health. MRSA possesses an arsenal of secreted host-damaging virulence factors that mediate pathogenicity and blunt immune defenses. Panton–Valentine leukocidin (PVL) and α-toxin are exotoxins that create lytic pores in the host cell membrane. They are recognized as being important for the development of invasive MRSA infections and are thus potential targets for antivirulence therapies. Here, we report the high-resolution X-ray crystal structures of both PVL and α-toxin in their soluble, monomeric, and oligomeric membrane-inserted pore states in complex with n-tetradecylphosphocholine (C14PC). The structures revealed two evolutionarily conserved phosphatidylcholine-binding mechanisms and their roles in modulating host cell attachment, oligomer assembly, and membrane perforation. Moreover, we demonstrate that the soluble C14PC compound protects primary human immune cells in vitro against cytolysis by PVL and α-toxin and hence may serve as the basis for the development of an antivirulence agent for managing MRSA infections.

Phosphatidylethanolamine recognition promotes enteropathogenic E. coli and enterohemorrhagic E. coli host cell attachment

1999 ◽  
Vol 27 (5) ◽  
pp. 289-301 ◽  
Author(s):  
Debora Barnett Foster ◽  
Dana Philpott ◽  
Maan Abul-Milh ◽  
Mario Huesca ◽  
Philip M Sherman ◽  
...  
Keyword(s):  
Host Cell ◽  
Cell Attachment ◽  
E Coli ◽  
Host Cell Attachment

Host cell attachment elicits posttranscriptional regulation in infecting enteropathogenic bacteria

Science ◽  
2017 ◽  
Vol 355 (6326) ◽  
pp. 735-739 ◽  
Author(s):  
Naama Katsowich ◽  
Netanel Elbaz ◽  
Ritesh Ranjan Pal ◽  
Erez Mills ◽  
Simi Kobi ◽  
...  
Keyword(s):  
Host Cell ◽  
Posttranscriptional Regulation ◽  
Cell Attachment ◽  
Enteropathogenic Bacteria ◽  
Host Cell Attachment

scholarly journals Expression and Localization of an Hsp70 Protein in the MicrosporidianEncephalitozoon cuniculi

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Carrie E. Jolly ◽  
Cory A. Leonard ◽  
J. Russell Hayman
Keyword(s):  
Host Cell ◽  
Cell Attachment ◽  
Surface Protein ◽  
Surface Proteins ◽  
Spore Surface ◽  
Dna Encoding ◽  
Hsp70 Protein ◽  
Surface Protein Expression ◽  
Host Cell Attachment ◽  
Spore Adherence

Microsporidia spore surface proteins are an important, under investigated aspect of spore/host cell attachment and infection. For comparison analysis of surface proteins, we required an antibody control specific for an intracellular protein. An endoplasmic reticulum-associated heat shock protein 70 family member (Hsp70; ECU02_0100; “C1”) was chosen for further analysis. DNA encoding the C1 hsp70 was amplified, cloned and used to heterologously express the C1 Hsp70 protein, and specific antiserum was generated. Two-dimensional Western blotting analysis showed that the purified antibodies were monospecific. Immunoelectron microscopy of developing and matureE. cuniculispores revealed that the protein localized to internal structures and not to the spore surface. In spore adherence inhibition assays, the anti-C1 antibodies did not inhibit spore adherence to host cell surfaces, whereas antibodies to a known surface adhesin (EnP1) did so. In future studies, the antibodies to the ‘C1’ Hsp70 will be used to delineate spore surface protein expression.

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