scholarly journals Tropheryma whipplei Twist: A Human Pathogenic Actinobacteria With a Reduced Genome

2003 ◽  
Vol 13 (8) ◽  
pp. 1800-1809 ◽  
Author(s):  
Didier Raoult ◽  
Hiroyuki Ogata ◽  
Stéphane Audic ◽  
Catherine Robert ◽  
Karsten Suhre ◽  
...  
Keyword(s):  
Cell Surface ◽  
Genome Sequence ◽  
Surface Protein ◽  
Large Cell ◽  
Tropheryma Whipplei ◽  
Surface Proteins ◽  
Molecular Diagnostic ◽  
Diagnostic Tools ◽  
Human Pathogen ◽  
Reduced Genome

The human pathogen Tropheryma whipplei is the only known reduced genome species (<1 Mb) within the Actinobacteria [high G+C Gram-positive bacteria]. We present the sequence of the 927,303-bp circular genome of T. whipplei Twist strain, encoding 808 predicted protein-coding genes. Specific genome features include deficiencies in amino acid metabolisms, the lack of clear thioredoxin and thioredoxin reductase homologs, and a mutation in DNA gyrase predicting a resistance to quinolone antibiotics. Moreover, the alignment of the two available T. whipplei genome sequences (Twist vs. TW08/27) revealed a large chromosomal inversion the extremities of which are located within two paralogous genes. These genes belong to a large cell-surface protein family defined by the presence of a common repeat highly conserved at the nucleotide level. The repeats appear to trigger frequent genome rearrangements in T. whipplei, potentially resulting in the expression of different subsets of cell surface proteins. This might represent a new mechanism for evading host defenses. The T. whipplei genome sequence was also compared to other reduced bacterial genomes to examine the generality of previously detected features. The analysis of the genome sequence of this previously largely unknown human pathogen is now guiding the development of molecular diagnostic tools and more convenient culture conditions.

Structure and expression of two temperature-specific surface proteins in the ciliated protozoan Tetrahymena thermophila

1986 ◽  
Vol 6 (9) ◽  
pp. 3240-3245
Author(s):  
G A Bannon ◽  
R Perkins-Dameron ◽  
A Allen-Nash
Keyword(s):  
Cell Surface ◽  
Specific Surface ◽  
Incubation Temperature ◽  
Tetrahymena Thermophila ◽  
Sodium Dodecyl ◽  
Surface Protein ◽  
Surface Proteins ◽  
Ciliated Protozoan ◽  
Temperature Dependent ◽  
Molecular Sizes

The presence of specific proteins (known as immobilization antigens) on the surface of the ciliated protozoan Tetrahymena thermophila is under environmental regulation. There are five different classes (serotypes) of surface proteins which appear on the cell surface when T. thermophila is cultured under different conditions of temperature or incubation medium; three of these are temperature dependent. The appearance of these proteins on the cell surface is mutually exclusive. We used polyclonal antibodies raised against 30 degrees C (designated SerH3)- and 40 degrees C (designated SerT)-specific surface antigens to study their structure and expression. We showed that these surface proteins contain at least one disulfide bridge. On sodium dodecyl sulfate-denaturing polyacrylamide gels, the nonreduced 30 degrees C- and 40 degrees C-specific surface proteins migrated with molecular sizes of 69 and 36 kilodaltons, respectively. The reduced forms of the proteins migrated with molecular sizes of 58 and 30 kilodaltons, respectively. The synthesis of the surface proteins responded rapidly and with a time course similar to that of the incubation temperature. The synthesis of each surface protein was greatly reduced within 1 h and undetectable by 2 h after a shift to the temperature at which the protein is not expressed. Surface protein synthesis resumed by the end of 1 h after a shift to the temperature at which the protein is expressed. The temperature-dependent induction of these surface proteins appears to be dependent on the synthesis of new mRNA, as indicated by a sensitivity to actinomycin D. Surface protein syntheses were mutually exclusive except at a transition temperature. At 35 degrees C both surface proteins were synthesized by a cell population. These data support the potential of this system as a model for the study of the effects of environmental factors on the genetic regulation of cell surface proteins.

Electrophoretic and Chemical Characterization of the Charged Groups at the Surface of Murine CL3 Ascites Leukaemia Cells

1969 ◽  
Vol 4 (2) ◽  
pp. 289-298
Author(s):  
P. D. WARD ◽  
E. J. AMBROSE
Keyword(s):  
Sialic Acid ◽  
Cell Surface ◽  
Chemical Characterization ◽  
Surface Protein ◽  
Subsequent Treatment ◽  
Surface Proteins ◽  
Carboxyl Groups ◽  
Neuraminidase Treatment ◽  
Ionic Nature ◽  
Ph Range

The electrophoretic characteristics of the murine CL3 ascites tumour were investigated. Treatment of the cells with formaldehyde raised the electrophoretic mobility (E.P.M.) from - 1.06 to - 1.28 µ/sec/V/cm; subsequent treatment with diazomethane reduced their mobility to zero. The E.P.M. of the diazomethane-treated cells did not alter over the pH range 3.0-8.0. This proved that the only ionic groups at this cell surface were amino and carboxyl groups. The absence of phosphate groups, another possibility, was confirmed by the lack of calcium-ion binding from 10 mM Ca2+ solutions. Neuraminidase treatment reduced the E.P.M. from -1.06 to -0.55 µ/sec/V/cm and free sialic acid was identified in the enzyme supernatant. Subsequent treatment of the cells with formaldehyde raised the mobility to -1.22 µ/sec/V/cm indicating that the change in E.P.M. on neuraminidase treatment was not due solely to the removal of the carboxyl groups of sialic acid but also to a change in the ionic nature of the surface. This change is ascribed to a change in the conformation of the surface protein. The reason for this change and a suggestion for the possible role of sialic acid at the cell surface are mentioned. Treatment of the cells with trypsin did not affect the viable cells in any way, suggesting that the surface proteins lack the basic amino acids lysine and arginine. Pronase treatment served only to show that much of the sialic acid was bound to protein; the total amount was not determined.

scholarly journals Are Staphylococcus intermedius Infections in Humans Cases of Mistaken Identity? A Case Series and Literature Review

2015 ◽  
Vol 2 (3) ◽  
Author(s):  
Roberto Viau ◽  
Andrea M. Hujer ◽  
Kristine M. Hujer ◽  
Robert A. Bonomo ◽  
Robin L.P. Jump
Keyword(s):  
Literature Review ◽  
Molecular Diagnostics ◽  
Case Series ◽  
Molecular Diagnostic ◽  
Diagnostic Tools ◽  
Human Pathogen ◽  
Detailed Review ◽  
Mistaken Identity ◽  
Staphylococcus Intermedius ◽  
Microbiological Methods

Abstract Staphylococcus intermedius and Staphylococcus pseudintermedius are difficult to distinguish using conventional microbiological methods. Molecular diagnostic tools change our understanding of the epidemiology of these 2 organisms. In this study, we present (1) a detailed review of the current literature on molecular diagnostics and (2) a case series in which misidentification was proven in 1 case. We conclude that S pseudintermedius is a more common human pathogen than previously recognized.

288 CHARACTERIZATION OF PORCINE ADIPOSE TISSUE-DERIVED ADULT STEM CELL SURFACE PROTEINS

2009 ◽  
Vol 21 (1) ◽  
pp. 241
Author(s):  
K. J. Williams ◽  
R. A. Godke ◽  
K. R. Bondioli
Keyword(s):  
Tissue Engineering ◽  
Adipose Tissue ◽  
Stem Cell ◽  
Cell Surface ◽  
Cell Lines ◽  
Adult Stem Cell ◽  
Surface Protein ◽  
Surface Proteins ◽  
Early Passage ◽  
Cell Surface Proteins

Human adipose tissue-derived adult stem (ADAS) cells are a self-renewing population of cells with a multilineage plasticity similar to bone marrow-derived mesenchymal stem cells. Human ADAS have promise for use in combination with various biomaterials for reconstructive tissue engineering. The phenotypic profile of human ADAS cell surface proteins has been partially characterized for stem cell-associated cluster differentiation molecules including CD29, CD44, and CD90. Porcine ADAS cells, an animal model for tissue engineering, also have the ability to self-renew and differentiate into multiple tissue lineages. However, the surface protein phenotype has not been described. Because porcine ADAS are isolated from fat depots likely different from human ADAS liposuction aspirates, it is important to characterize these cells. In this study, we have partially characterized the surface protein phenotype of undifferentiated porcine ADAS cells in comparison with the immunophenotype of undifferentiated human ADAS cells as reported in the literature. Flow cytometry and enhanced chemiluminescence Western blot analysis of early passage (passages 0–4) porcine ADAS cell populations demonstrated that the profiles are not similar to the human ADAS cell surface. Immunoblot detection paired with an enhanced chemiluminescence kit revealed a positive expression for CD44 and CD90 in human ADAS cells as indicated by bands present at the expected sizes and a negative expression for CD44 and CD90 in porcine ADAS cells. Flow cytometric analysis also indicated differences between human and early passage porcine ADAS cell surfaces with a relatively low expression of CD29 (5 cell lines with a mean percent positive of 4.5 ± 1.7 and a range of 2.5–7.2%) and CD44 (5 cell lines with a mean percent positive of 0.66 ± 0.67 and a range of 0.0–1.8%) compared with human ADAS values of 98 ± 1 and 60 ± 15, respectively (Gronthos et al. 2001). Other cell surface proteins analyzed at early passages include CD3 (3 cell lines; 0.07 ± 0.06% positive and 0.0–0.1 range), CD8 (3 cell lines; 0.10 ± 0.10% positive and 0–0.2 range), and CD90 [5 cell lines; 12.7 ± 11.9% positive and 2.4–33 range; human ADAS geometric mean 25.96% (Zuk et al. 2002)]. Analysis of late passage (passages 5–11) porcine ADAS cell populations revealed an increased expression of CD29 (3 cell lines; 26.4 ± 7.2% positive and 21.2–34.6 range). The expression level of CD90 at late passages were 21.3 and 26.9% positive for 2 cell lines and CD44 remained low (3 cell lines; 4.1 ± 3.5% positive and 0.2–7.0 range). Later passages were also analyzed for c-Kit (CD117), which was expressed at low levels (2 cell lines; 0.3 and 0.4% positive). The characterization of adipose tissue-derived adult stem cell surface proteins present at different stages of in vitro culture from a model animal, such as the pig, could have valuable impacts on tissue engineering research. These results suggest that care should be taken when interpreting results from animal models of somatic stem cells.

scholarly journals The in silico human surfaceome

2018 ◽  
Vol 115 (46) ◽  
pp. E10988-E10997 ◽  
Author(s):  
Damaris Bausch-Fluck ◽  
Ulrich Goldmann ◽  
Sebastian Müller ◽  
Marc van Oostrum ◽  
Maik Müller ◽  
...  
Keyword(s):  
Cell Surface ◽  
In Silico ◽  
Embryonic Stem ◽  
Surface Protein ◽  
Surface Proteins ◽  
Cell Surface Protein ◽  
Cell Surface Proteins ◽  
A Cell ◽  
Visualization Tools ◽  
Protein Classes

Cell-surface proteins are of great biomedical importance, as demonstrated by the fact that 66% of approved human drugs listed in the DrugBank database target a cell-surface protein. Despite this biomedical relevance, there has been no comprehensive assessment of the human surfaceome, and only a fraction of the predicted 5,000 human transmembrane proteins have been shown to be located at the plasma membrane. To enable analysis of the human surfaceome, we developed the surfaceome predictor SURFY, based on machine learning. As a training set, we used experimentally verified high-confidence cell-surface proteins from the Cell Surface Protein Atlas (CSPA) and trained a random forest classifier on 131 features per protein and, specifically, per topological domain. SURFY was used to predict a human surfaceome of 2,886 proteins with an accuracy of 93.5%, which shows excellent overlap with known cell-surface protein classes (i.e., receptors). In deposited mRNA data, we found that between 543 and 1,100 surfaceome genes were expressed in cancer cell lines and maximally 1,700 surfaceome genes were expressed in embryonic stem cells and derivative lines. Thus, the surfaceome diversity depends on cell type and appears to be more dynamic than the nonsurface proteome. To make the predicted surfaceome readily accessible to the research community, we provide visualization tools for intuitive interrogation (wlab.ethz.ch/surfaceome). The in silico surfaceome enables the filtering of data generated by multiomics screens and supports the elucidation of the surfaceome nanoscale organization.

scholarly journals A Novel Sortase, SrtC2, from Streptococcus pyogenes Anchors a Surface Protein Containing a QVPTGV Motif to the Cell Wall

2004 ◽  
Vol 186 (17) ◽  
pp. 5865-5875 ◽  
Author(s):  
Timothy C. Barnett ◽  
Aman R. Patel ◽  
June R. Scott
Keyword(s):  
Cell Wall ◽  
Streptococcus Pyogenes ◽  
Group A Streptococcus ◽  
Surface Protein ◽  
Surface Proteins ◽  
Human Pathogen ◽  
Hydrophobic Region ◽  
C Terminus ◽  
Group A ◽  
Covalently Linked

ABSTRACT The important human pathogen Streptococcus pyogenes (group A streptococcus GAS), requires several surface proteins to interact with its human host. Many of these are covalently linked by a sortase enzyme to the cell wall via a C-terminal LPXTG motif. This motif is followed by a hydrophobic region and charged C terminus, which are thought to retard the protein in the cell membrane to facilitate recognition by the membrane-localized sortase. Previously, we identified two sortase enzymes in GAS. SrtA is found in all GAS strains and anchors most proteins containing LPXTG, while SrtB is present only in some strains and anchors a subset of LPXTG-containing proteins. We now report the presence of a third sortase in most strains of GAS, SrtC. We show that SrtC mediates attachment of a protein with a QVPTGV motif preceding a hydrophobic region and charged tail. We also demonstrate that the QVPTGV sequence is a substrate for anchoring of this protein by SrtC. Furthermore, replacing this motif with LPSTGE, found in the SrtA-anchored M protein of GAS, leads to SrtA-dependent secretion of the protein but does not lead to its anchoring by SrtA. We conclude that srtC encodes a novel sortase that anchors a protein containing a QVPTGV motif to the surface of GAS.

scholarly journals Identification of phagocytosis-associated surface proteins of macrophages by two-dimensional gel electrophoresis.

1982 ◽  
Vol 92 (2) ◽  
pp. 283-288 ◽  
Author(s):  
F D Howard ◽  
H R Petty ◽  
H M McConnell
Keyword(s):  
Cell Surface ◽  
Gel Electrophoresis ◽  
Protein Composition ◽  
Surface Protein ◽  
Surface Proteins ◽  
Two Dimensional ◽  
Cell Surface Protein ◽  
Two Dimensional Gel Electrophoresis ◽  
Reducing Conditions ◽  
Membrane Components

Two-dimensional PAGE (P. Z. O'Farrell, H. M. Goodman, and P. H. O'Farrell. 1977. Cell. 12:1133-1142) has been employed to assess the effects of antibody-dependent phagocytosis on the cell surface protein composition of RAW264 macrophages. Unilamellar phospholipid vesicles containing 1% dinitrophenyl-aminocaproyl-phosphatidylethanolamine (DNP-cap-PE) were used as the target particle. Macrophages were exposed to anti-DNP antibody alone, vesicles alone, or vesicles in the presence of antibody for 1 h at 37 degrees C. Cell surface proteins were then labeled by lactoperoxidase-catalyzed radioiodination at 4 degrees C. After detergent solubilization, membrane proteins were analyzed by two-dimensional gel electrophoresis. The resulting pattern of spots was compared to that of standard proteins. We have identified several surface proteins, not apparently associated with the phagocytic process, which are present either in a multichain structure or in several discretely charged forms. After phagocytosis, we have observed the appearance of two proteins of 45 and 50 kdaltons in nonreducing gels. In addition, we have noted the disappearance of a 140-kdalton protein in gels run under reducing conditions. These alterations would not be detected in the conventional one-dimensional gel electrophoresis. This evidence shows that phagocytosis leads to a modification of cell surface protein composition. Our results support the concept of specific enrichment and depletion of membrane components during antibody-dependent phagocytosis.

scholarly journals The Tight Junction-Associated Protein Occludin Is Required for a Postbinding Step in Hepatitis C Virus Entry and Infection

2009 ◽  
Vol 83 (16) ◽  
pp. 8012-8020 ◽  
Author(s):  
Ignacio Benedicto ◽  
Francisca Molina-Jiménez ◽  
Birke Bartosch ◽  
François-Loïc Cosset ◽  
Dimitri Lavillette ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Cell Surface ◽  
Tight Junction ◽  
Essential Role ◽  
Surface Protein ◽  
Hcv Infection ◽  
Surface Proteins ◽  
Target Cells ◽  
Type I

ABSTRACT The precise mechanisms regulating hepatitis C virus (HCV) entry into hepatic cells remain unknown. However, several cell surface proteins have been identified as entry factors for this virus. Of these molecules, claudin-1, a tight junction (TJ) component, is considered a coreceptor required for HCV entry. Recently, we have demonstrated that HCV envelope glycoproteins (HCVgp) promote structural and functional TJ alterations. Additionally, we have shown that the intracellular interaction between viral E2 glycoprotein and occludin, another TJ-associated protein, could be the cause of the mislocalization of TJ proteins. Herein we demonstrated, by using cell culture-derived HCV particles (HCVcc), that interference of occludin expression markedly reduced HCV infection. Furthermore, our results with HCV pseudotyped particles indicated that occludin, but not other TJ-associated proteins, such as junctional adhesion molecule A or zonula occludens protein 1, was required for HCV entry. Using HCVcc, we demonstrated that occludin did not play an essential role in the initial attachment of HCV to target cells. Surface protein labeling experiments showed that both expression levels and cell surface localization of HCV (co)receptors CD81, scavenger receptor class B type I, and claudin-1 were not affected upon occludin knockdown. In addition, immunofluorescence confocal analysis showed that occludin interference did not affect subcellular distribution of the HCV (co)receptors analyzed. However, HCVgp fusion-associated events were altered after occludin silencing. In summary, we propose that occludin plays an essential role in HCV infection and probably affects late entry events. This observation may provide new insights into HCV infection and related pathogenesis.

scholarly journals Microfluidic Techniques for Single-Cell Protein Expression Analysis

2006 ◽  
Vol 52 (6) ◽  
pp. 1080-1088 ◽  
Author(s):  
Ethan Fitzpatrick ◽  
Sterling McBride ◽  
Jonathan Yavelow ◽  
Saltanat Najmi ◽  
Peter Zanzucchi ◽  
...  
Keyword(s):  
Cell Surface ◽  
Protein Expression ◽  
Cancer Cells ◽  
Microfluidic Device ◽  
Single Cells ◽  
Surface Protein ◽  
Surface Proteins ◽  
Cell Protein ◽  
Surface Protein Expression ◽  
Mcf 7

Abstract Background: The analysis of single cells obtained from needle aspirates of tumors is constrained by the need for processing. To this end, we investigated two microfluidic approaches to measure the expression of surface proteins in single cancer cells or in small populations (&lt;50 cells). Methods: One approach involved indirect fluorescence labeling of cell-surface proteins and channeling of cells in a microfluidic device past a fluorescence detector for signal quantification and analysis. A second approach channeled cells in a microfluidic device over detection zones coated with ligands to surface proteins and measured rates of passage and of retardation based on transient interactions between surface proteins and ligands. Results: The fluorescence device detected expression of integrin α5 induced by basic fibroblast growth factor (FGF-2) treatment in MCF-7 cells and that of Her-2/neu in SK-BR-3 cells compared with controls. Experiments measuring passage retardation showed significant differences in passage rates between FGF-2–treated and untreated MCF-7 cells over reaction regions coated with fibronectin and antibody to integrin α5β1 compared with control regions. Blocking peptides reversed the retardation, demonstrating specificity. Conclusions: Immunofluorescence detection in a microfluidic channel demonstrates the potential for assaying surface protein expression in a few individual cells and will permit the development of future iterations not requiring cell handling. The flow retardation device represents the first application of this technology for assessing cell-surface protein expression in cancer cells and may provide a way for analyzing expression profiles of single cells without preanalytical manipulation.

scholarly journals Transcription Factor Control of Dendrite Targeting via Combinatorial Cell-Surface Codes

2021 ◽  
Author(s):  
Liqun Luo ◽  
Qijing Xie ◽  
Jiefu Li ◽  
Hongjie Li ◽  
Namrata Udeshi ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Cell Surface ◽  
Surface Protein ◽  
Surface Proteins ◽  
Projection Neurons ◽  
Cell Surface Protein ◽  
Cell Surface Proteins ◽  
Cellular Environment ◽  
Combinatorial Expression

Abstract Transcription factors are central commanders specifying cell fate, morphology, and physiology while cell-surface proteins execute these commands through interaction with cellular environment. In developing neurons, it is presumed that transcription factors control wiring specificity through regulation of cell-surface protein expression. However, the number and identity of cell-surface protein(s) a transcription factor regulates remain largely unclear1,2. Also unknown is whether a transcription factor regulates the same or different cell-surface proteins in different neuron types to specify their connectivity. Here we use a lineage-defining transcription factor, Acj6 (ref. 3), to investigate how it controls precise dendrite targeting of Drosophila olfactory projection neurons (PNs). Quantitative cell-surface proteomic profiling of wild-type and acj6 mutant PNs in intact developing brains and a proteome-informed genetic screen identified PN surface proteins that execute Acj6-regulated wiring decisions. These include canonical cell adhesion proteins and proteins previously not associated with wiring, such as the mechanosensitive ion channel Piezo—whose channel activity is dispensable for its wiring function. Comprehensive genetic analyses revealed that Acj6 employs unique sets of cell-surface proteins in different PN types for dendrite targeting. Combinatorial expression of Acj6 wiring executors rescued acj6 mutant phenotypes with higher efficacy and breadth than expression of individual executors. Thus, a key transcription factor controls wiring specificity of different neuron types by specifying distinct combinatorial expression of cell-surface executors.

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