Effects of fibronectin on the compact colony formation in staphylococci

1984 ◽  
Vol 30 (3) ◽  
pp. 419-422 ◽  
Author(s):  
Yukio Usui ◽  
Yukio Ohshima ◽  
Kosaku Yoshida
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Surface ◽  
Staphylococcus Epidermidis ◽  
Colony Formation ◽  
Protein A ◽  
Soft Agar ◽  
Cellular Factor ◽  
Diffuse Growth

Fifty-two unencapsulated strains of Staphylococcus aureus, including strains of Wood 46 and Cowan I, formed compact colonies in fibronectin – soft agar. However, 20 encapsulated strains of Staphylococcus aureus and 50 strains of Staphylococcus epidermidis showed diffuse growth in the medium. The results suggest that another possible cellular factor, other than protein A, is involved in the binding of the cell surface with fibronectin and that it would be one of factors in forming compact colonies in serum – soft agar.

Replication Protein A 3 Is Associated with Hepatocellular Carcinoma Tumorigenesis and Poor Patient Survival

2017 ◽  
Vol 36 (1) ◽  
pp. 26-32 ◽  
Author(s):  
Wenbo Xiao ◽  
Jun Zheng ◽  
Baoyong Zhou ◽  
Long Pan
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Proliferation ◽  
Tumor Progression ◽  
Colony Formation ◽  
Patient Survival ◽  
Protein A ◽  
Replication Protein A ◽  
Soft Agar ◽  
Replication Protein ◽  
High Expression

Background: Replication protein A (RPA) 3 is a subunit of the RPA protein complex, which functions in multiple processes of DNA metabolism. Dysregulation of RPA1 and RPA2 has been implicated in tumor progression in several cancer types. However, the function of RPA3 in hepatocellular carcinoma (HCC) tumorigenesis has not been elucidated. Method: In this study, we investigated the function of RPA3 in HCC development by stably knocking down its expression using short hairpin RNA (shRNA) in HepG2 cell line, followed by cell proliferation, colony formation, soft agar, and invasion assays. Xenograft experiment was performed to examine in vivo tumor-promoting properties of RPA3. Results: Downregulation of RPA3-inhibited cell proliferation, colony formation, soft agar growth as well as invasion in HepG2 cells were observed. Stable knockdown of RPA3 significantly inhibited tumor growth in the xenograft mouse model. In addition, qRT-PCR analysis revealed that RPA3 was upregulated in human HCC tissues compared with matched noncancerous adjacent tissues (NATs). High expression of RPA3 was associated with poor overall survival and disease-free survival. Conclusion: Elevated expression of RPA3 promotes tumor progression in HCC cells. RPA3 is upregulated in HCC tissues and high expression of RPA3 is associated with poorer patient survival. Therefore, this protein may represent a novel therapeutic target for intervention of HCC and prognostic biomarker for patient survival.

Binding of staphylococcal cell surface polysaccharide to human fibrinogen

1990 ◽  
Vol 36 (3) ◽  
pp. 206-210
Author(s):  
Toshichika Ohtomo ◽  
Tsugiaki Kobayashi ◽  
Yukio Ohshima ◽  
Yukio Usui ◽  
Masaru Suganuma ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Surface ◽  
Binding Site ◽  
Key Words ◽  
Active Substance ◽  
Soft Agar ◽  
Alkaline Ph ◽  
Human Fibrinogen ◽  
Surface Polysaccharide ◽  
Alkaline Range

The interaction between the binding site of a polysaccharide (called compact colony forming active substance (CCFAS)), obtained from the cell surface of a strain of Staphylococcus, and human fibrinogen (HF) was investigated. The CCFAS was found to bind specifically to both the Bβ and γ chains of HF at pH 7.0 and 8.0, and the Aα chain at pH 5.0. The binding of CCFAS with fibrinogen fragments obtained by digestion with plasmin were also investigated. Fragments with Mr of 55 000, 24 000, and 19 000 were the major bands precipitated by CCFAS at pH 7.0 and 8.0. Fragments with Mr of 85 000 and 75 000 bound to CCFAS at pH 5.0. Binding of CCFAS (7 μg) with fibrinogen could be inhibited by 1.2 μg of Bβ chain and 1.5 μg γ chain at alkaline pH or 6.2 μg of the Aα chain at pH 5.0. CCFAS was, therefore, assumed to be specifically bonded with HF molecules, in the alkaline range at least, resulting in compact colony forming activity in serum soft agar and paracoagulation. Key words: cell surface, polysaccharide, Staphylococcus aureus, fibrinogen.

scholarly journals Staphylococcal Surface Display of Immunoglobulin A (IgA)- and IgE-Specific In Vitro-Selected Binding Proteins (Affibodies) Based on Staphylococcus aureus Protein A

1999 ◽  
Vol 65 (9) ◽  
pp. 4134-4140 ◽  
Author(s):  
Elin Gunneriusson ◽  
Patrik Samuelson ◽  
Jenny Ringdahl ◽  
Hans Grönlund ◽  
Per-Åke Nygren ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Surface ◽  
Binding Capacity ◽  
Expression System ◽  
Surface Display ◽  
Protein A ◽  
Surface Proteins ◽  
Phage Library ◽  
Protein Chemistry ◽  
Ige Binding

ABSTRACT An expression system designed for cell surface display of hybrid proteins on Staphylococcus carnosus has been evaluated for the display of Staphylococcus aureus protein A (SpA) domains, normally binding to immunoglobulin G (IgG) Fc but here engineered by combinatorial protein chemistry to yield SpA domains, denoted affibodies, with new binding specificities. Such affibodies, with human IgA or IgE binding activity, have previously been selected from a phage library, based on an SpA domain. In this study, these affibodies have been genetically introduced in monomeric or dimeric forms into chimeric proteins expressed on the surface of S. carnosus by using translocation signals from aStaphylococcus hyicus lipase construct together with surface-anchoring regions of SpA. The recombinant surface proteins, containing the IgA- or IgE-specific affibodies, were demonstrated to be expressed as full-length proteins, localized and properly exposed at the cell surface of S. carnosus. Furthermore, these chimeric receptors were found to be functional, since recombinantS. carnosus cells were shown to have gained IgA and IgE binding capacity, respectively. In addition, a positive effect in terms of IgA and IgE reactivity was observed when dimeric versions of the affibodies were present. Potential applications for recombinant bacteria with redirected binding specificity in their surface proteins are discussed.

scholarly journals Staphylococcus aureus Fibronectin-Binding Protein A Mediates Cell-Cell Adhesion through Low-Affinity Homophilic Bonds

mBio ◽  
2015 ◽  
Vol 6 (3) ◽  
Author(s):  
Philippe Herman-Bausier ◽  
Sofiane El-Kirat-Chatel ◽  
Timothy J. Foster ◽  
Joan A. Geoghegan ◽  
Yves F. Dufrêne
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Surface ◽  
Biofilm Formation ◽  
Protein A ◽  
Intercellular Adhesion ◽  
Surface Proteins ◽  
Content Type ◽  
Fibronectin Binding ◽  
A Domains ◽  
Cell Cell

ABSTRACT Staphylococcus aureus is an important opportunistic pathogen which is a leading cause of biofilm-associated infections on indwelling medical devices. The cell surface-located fibronectin-binding protein A (FnBPA) plays an important role in the accumulation phase of biofilm formation by methicillin-resistant S. aureus (MRSA), but the underlying molecular interactions are not yet established. Here, we use single-cell and single-molecule atomic force microscopy to unravel the mechanism by which FnBPA mediates intercellular adhesion. We show that FnBPA is responsible for specific cell-cell interactions that involve the FnBPA A domain and cause microscale cell aggregation. We demonstrate that the strength of FnBPA-mediated adhesion originates from multiple low-affinity homophilic interactions between FnBPA A domains on neighboring cells. Low-affinity binding by means of FnBPA may be important for biofilm dynamics. These results provide a molecular basis for the ability of FnBPA to promote cell accumulation during S. aureus biofilm formation. We speculate that homophilic interactions may represent a generic strategy among staphylococcal cell surface proteins for guiding intercellular adhesion. As biofilm formation by MRSA strains depends on proteins rather than polysaccharides, our approach offers exciting prospects for the design of drugs or vaccines to inhibit protein-dependent intercellular interactions in MRSA biofilms. IMPORTANCE Staphylococcus aureus is a human pathogen that forms biofilms on indwelling medical devices, such as central venous catheters and prosthetic joints. This leads to biofilm infections that are difficult to treat with antibiotics because many cells within the biofilm matrix are dormant. The fibronectin-binding proteins (FnBPs) FnBPA and FnBPB promote biofilm formation by clinically relevant methicillin-resistant S. aureus (MRSA) strains, but the molecular mechanisms involved remain poorly understood. We used atomic force microscopy techniques to demonstrate that FnBPA mediates cell-cell adhesion via multiple, low-affinity homophilic bonds between FnBPA A domains on adjacent cells. Therefore, FnBP-mediated homophilic interactions represent an interesting target to prevent MRSA biofilms. We propose that such homophilic mechanisms may be widespread among staphylococcal cell surface proteins, providing a means to guide intercellular adhesion and biofilm accumulation.

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