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Bonot S, Ogorzaly L, El Moualij B, Zorzi W, Cauchie HM. Detection of small amounts of human adenoviruses in stools: comparison of a new immuno real-time PCR assay with classical tools. Clin Microbiol Infect 2014; 20:O1010-6. [PMID: 25041100 PMCID: PMC7162227 DOI: 10.1111/1469-0691.12768] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 06/02/2014] [Accepted: 07/09/2014] [Indexed: 11/29/2022]
Abstract
The detection of low virus concentrations in biological matrices, especially stool samples, is facing significant limitations as far as common diagnostic methods (enzyme-linked-immunosorbent assay (ELISA) or quantitative real-time PCR (qPCR)) are considered. Here the development of a new immuno real-time PCR (iPCR) is described and its performance in the detection of human adenoviruses (HAdVs) in spiked stools is compared with those of ELISA and qPCR assays. For the iPCR, detection of the sandwich formed by the complexation of capture antibody-antigen-detection antibody was performed by qPCR thanks to the substitution of peroxydase by a chimeric DNA. This modification increased the detection sensitivity 200-fold compared to ELISA. The direct qPCR results revealed that only 0.3–9.5% of the spiked HAdV were detectable, resulting from important losses of DNA occurring at the extraction step. This step was not necessary in the iPCR workflow, avoiding this drawback. The losses of viral particles occurred at the elution step from the stool only. The recovery rate of the iPCR was thus better and ranged between 21 and 54%. As a result, iPCR enabled the detection of lower virus concentrations in stool samples compared to those detected by ELISA and qPCR. The iPCR could be considered as a ‘hyper sensitive ELISA’ for early detection of HAdV infections, especially in the case of immunocompromised patients after haematopoietic stem cell transplant.
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Affiliation(s)
- S Bonot
- Centre de Recherche Public-Gabriel Lippmann, Department of Environment and Agro-biotechnologies (EVA), Belvaux, Luxembourg
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Vrlinic T, Debarnot D, Legeay G, Coudreuse A, El Moualij B, Zorzi W, Perret-Liaudet A, Quadrio I, Mozetic M, Poncin-Epaillard F. How to control the recombinant prion protein adhesion for successful storage through modification of surface properties. Biointerphases 2012; 7:66. [PMID: 23109107 DOI: 10.1007/s13758-012-0066-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 10/16/2012] [Indexed: 11/25/2022] Open
Abstract
Depletion of neuroproteins on the inner walls of storage tubes influences the accuracy of tests used for identification of various neurodegenerative disorders. In this paper, a strategy is described for surface modification of Eppendorf tubes leading to non-adhesive properties towards the recombinant human prion proteins (PrPrec(hum)). Tubes were pre-activated by helium plasma and grafted with three diverse coatings: pure poly(N-isopropylacrylamide) (PNIPAM), PNIPAM admixed with either neutral PEG(20)sorbitan monolaurate (PEG(20)) or positively charged cetyl trimethylammonium bromide (CTAB) at varying plasma activation times and polymer to surfactant ratios. New functionalized surfaces were analyzed by goniometry, streaming potential measurement and X-ray photoelectron spectroscopy, whereas the protein adhesion was monitored by enzyme linked immunosorbent assays and confocal microscopy. The mapping of PrPrec(hum) adhesion associated with surface analyses enabled us to determine that no or negligible depletion of PrPrec(hum) can be obtained by surfaces possessing basic component in the range between 50 and 60 mJ m(-2) and streaming potential ζ(7.4) - -50 mV.
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Affiliation(s)
- T Vrlinic
- Département Polymères Colloïdes et Interfaces, Institut des Molécules et Matériaux du Mans, LUNAM Université, UMR Université du Maine, CNRS n° 6283, Avenue Olivier Messiaen, 72085 Le Mans Cedex, France
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Mille C, Debarnot D, Zorzi W, El Moualij B, Coudreuse A, Legeay G, Quadrio I, Perret-Liaudet A, Poncin-Epaillard F. Improvement of the Detection of Neurodegenerative Alzheimer's Disease through a Specific Surface Chemistry Applied onto the Inner Surface of the Titration Well. Journal of Biomaterials Science, Polymer Edition 2012; 23:1951-61. [DOI: 10.1163/092050611x600712] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- C. Mille
- a LUNAM Universite, Laboratoire Polymeres, Colloides et Interfaces, UMR CNRS 6120 — Universite du Maine , Avenue O. Messiaen, 72085 , Le Mans , France
| | - D. Debarnot
- a LUNAM Universite, Laboratoire Polymeres, Colloides et Interfaces, UMR CNRS 6120 — Universite du Maine , Avenue O. Messiaen, 72085 , Le Mans , France
| | - W. Zorzi
- b Centre de Recherche sur les Proteines Prion, Institut de Pharmacie , B36, 1 Avenue de l'Hopital, 4000 , Liege , Belgium
| | - B. El Moualij
- b Centre de Recherche sur les Proteines Prion, Institut de Pharmacie , B36, 1 Avenue de l'Hopital, 4000 , Liege , Belgium
| | - A. Coudreuse
- c CTTM , 20 rue Thales de Milet, 72000 , Le Mans , France
| | - G. Legeay
- c CTTM , 20 rue Thales de Milet, 72000 , Le Mans , France
| | - I. Quadrio
- d Centre Memoire de Ressources et Recherche, Service de Neuro iologie, Groupement Hospitalier Est du CHU , 56 Boulevard Pinel, 69677 , Bron cedex , France
| | - A. Perret-Liaudet
- d Centre Memoire de Ressources et Recherche, Service de Neuro iologie, Groupement Hospitalier Est du CHU , 56 Boulevard Pinel, 69677 , Bron cedex , France
| | - F. Poncin-Epaillard
- a LUNAM Universite, Laboratoire Polymeres, Colloides et Interfaces, UMR CNRS 6120 — Universite du Maine , Avenue O. Messiaen, 72085 , Le Mans , France
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Poncin-Epaillard F, Mille C, Debarnot D, Zorzi W, El Moualij B, Coudreuse A, Legeay G, Quadrio I, Perret-Liaudet A. Study of the Adhesion of Neurodegenerative Proteins on Plasma-Modified and Coated Polypropylene Surfaces. Journal of Biomaterials Science, Polymer Edition 2012; 23:1879-93. [DOI: 10.1163/156856211x598247] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- F. Poncin-Epaillard
- a LUNAM Universite, Laboratoire Polymères, Colloides et Interfaces, UMR CNRS 6120, Université du Maine , av. O. Messiaen, 72085 , Le Mans , France
| | - C. Mille
- a LUNAM Universite, Laboratoire Polymères, Colloides et Interfaces, UMR CNRS 6120, Université du Maine , av. O. Messiaen, 72085 , Le Mans , France
| | - D. Debarnot
- a LUNAM Universite, Laboratoire Polymères, Colloides et Interfaces, UMR CNRS 6120, Université du Maine , av. O. Messiaen, 72085 , Le Mans , France
| | - W. Zorzi
- b Centre de Recherche sur les Proteinés Prion, Institut de Pharmacie , B36, n°1 avenue de l'Hopital, 4000 , Liège , Belgium
| | - B. El Moualij
- b Centre de Recherche sur les Proteinés Prion, Institut de Pharmacie , B36, n°1 avenue de l'Hopital, 4000 , Liège , Belgium
| | - A. Coudreuse
- c CTTM , 20 rue Thalés de Milet, 72000 , Le Mans , France
| | - G. Legeay
- c CTTM , 20 rue Thalés de Milet, 72000 , Le Mans , France
| | - I. Quadrio
- d Service de Biochimie de l'hôpital Neurologique, Laboratoire de Diagnostic des Maladies à Prion , CHU, 56 bd Pinel, 69677 , Bron Cedex , France
| | - A. Perret-Liaudet
- d Service de Biochimie de l'hôpital Neurologique, Laboratoire de Diagnostic des Maladies à Prion , CHU, 56 bd Pinel, 69677 , Bron Cedex , France
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Ehirchiou D, Zorzi W, Biemans R, Vanderbeeke A, Haumont M, Coumans B, Collin S, Jolois O, Bollen A, Heinen E, Antoine N. DNA immunisation. New histochemical and morphometric data. Eur J Histochem 2003; 46:215-22. [PMID: 12472116 DOI: 10.4081/1682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Splenic germinal center reactions were measured during primary response to a plasmidic DNA intramuscular injection. Cardiotoxin-pretreated Balb/c mice were immunized with DNA plasmids encodmg or not the SAG1 protein, a membrane antigen of Toxoplasma gondii. Specific anti-SAG1 antibodies were detected on days 16 and 36 after injection of coding plasmids. The results of ELISAs showed that the SAG1-specific antibodies are of the IgG2a class. Morphometric analyses were done on serial immunostained cryosections of spleen and draining or non-draining lymph nodes. This new approach made it possible to evaluate the chronological changes induced by DNA immunisation in the germinal centres (in number and in size). Significant increases in the number of germinal centres were measured in the spleen and only in draining lymph nodes after plasmid injection, the measured changes of the germinal centers appeared to result from the adjuvant stimulatory effect of the plasmidic DNA since both the coding and the noncoding plasmid DNA induced them. No measurable changes were recorded in the T-dependent zone of lymph organs.
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Affiliation(s)
- D Ehirchiou
- Laboratory of Human Histology, University of Liège, Belgium.
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Abstract
Tolerance to the foetal 'allograft' has been extensively studied in the past few years, providing interesting new insights. In addition to a potential role for HLA-G, which has been widely discussed, there are hypotheses suggesting roles for several other molecules or cells: leukemia inhibitory factor and its receptor; indoleamine 2. 3-dioxygenase; the Th1/Th2 balance; suppressor macrophages; hormones such as progesterone or the placental growth hormone; CD95 and its ligand; and, as recently proposed, annexin II. Tolerance of the foetal allograft is probably the consequence of a wide panel of mechanisms that may or may not be pregnancy-specific, that are of major or secondary importance and that may be interconnected.
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Affiliation(s)
- O Thellin
- Institute of Human Histology, University of Liege, 20 Rue de Pitteurs, B-4020 Liege, Belgium
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Thellin O, Coumans B, Devos S, Hooghe-Peters EL, Zorzi W, Igout A, Heinen E, Hooghe R. Limited effects of placental and pituitary growth hormone on cytokine expression in vitro. Eur Cytokine Netw 2000; 11:452-5. [PMID: 11022131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The hypothesis that growth hormone (GH) can affect immune responses in man has been evaluated by monitoring cytokine expression in cultures from peripheral blood mononuclear cells, by enzyme-linked immunosorbent assay (ELISA) and ribonuclease protection assay, and in tonsillar cells by ELISA. In addition to pituitary GH (GH-N), the placental form (GH-V), differing from pituitary GH by 13 amino acids has also been tested. Only few effects reached statistical significance and were in no case greater than 15%. Pituitary GH slightly reduced IL-5 production and stimulated IFN-gamma production. The latter effect was also observed with prolactin and could thus be induced through the prolactin receptor. It is proposed that GH has no strong effects on the parameters investigated, possibly as a result of redundancy in the cytokine network. Alternatively, effects on leukocytes are mediated by other tissues such as the liver or are clear only in response to stronger challenges.
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Affiliation(s)
- O Thellin
- Pharmacology Department, Medical School, Free University of Brussels (VUB), Gebouw D, 103, Laarbeeklaan B-1090, Brussels Belgium
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Antoine N, Cesbron JY, Coumans B, Jolois O, Zorzi W, Heinen E. Differential expression of cellular prion protein on human blood and tonsil lymphocytes. Haematologica 2000; 85:475-80. [PMID: 10800162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
BACKGROUND AND OBJECTIVE The expression of cellular prion protein (PrPc) on the surface of peripheral lymphocytes has been previously reported, but little is known about its expression on lymphoid cells from secondary lymph organs. In this report, we compare the surface expression of PrPc on human blood lymphocytes and tonsil lymphocytes. DESIGN AND METHODS This analysis was performed by cytometry on live lymphocytes isolated from healthy donors or from the tonsils of adults or children. RESULTS Human peripheral lymphocytes and tonsillar lymphoid cells, but not erythrocytes or granulocytes, express PrPc at their surfaces. Interestingly, we found significantly less PrPc on freshly isolated tonsil lymphocytes, both B and T, than on blood cells. Although tonsil cells bear less PrPc than circulating blood lymphocytes, they are able to express high quantities of PrPc on their surface when placed in culture. However, contrary to previous results, mitogen stimulation does not affect this expression on B- or T-cells. INTERPRETATION AND CONCLUSIONS We suggest that the PrPc expression by lymphocytes may be modified by interactions occurring during intratissular migration or during cell-to-cell contacts. Whether PrPc plays a role in intracellular communication at this location, as it does in the nervous system, remains an open question.
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Affiliation(s)
- N Antoine
- Laboratory of Human Histology, University of Liège, Rue de Pitteurs, 20, B-4020 Liège, Belgium.
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Abstract
Quantitative studies are commonly realised in the biomedical research to compare RNA expression in different experimental or clinical conditions. These quantifications are performed through their comparison to the expression of the housekeeping gene transcripts like glyceraldehyde-3-phosphate dehydrogenase (G3PDH), albumin, actins, tubulins, cyclophilin, hypoxantine phsophoribosyltransferase (HRPT), L32. 28S, and 18S rRNAs are also used as internal standards. In this paper, it is recalled that the commonly used internal standards can quantitatively vary in response to various factors. Possible variations are illustrated using three experimental examples. Preferred types of internal standards are then proposed for each of these samples and thereafter the general procedure concerning the choice of an internal standard and the way to manage its uses are discussed.
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Affiliation(s)
- O Thellin
- Institute of Human Histology, University of Liège, Belgium
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Coumans B, Thellin O, Zorzi W, Melot F, Bougoussa M, Melen L, Zorzi D, Hennen G, Igout A, Heinen E. Lymphoid cell apoptosis induced by trophoblastic cells: a model of active foeto-placental tolerance. J Immunol Methods 1999; 224:185-96. [PMID: 10357218 DOI: 10.1016/s0022-1759(99)00021-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
To test the hypothesis that CD95-L (Fas-L) present on trophoblastic cells plays a part in establishing foeto-placental tolerance by inducing apoptosis of immune defence cells, we cocultured trophoblasts with lymphoid cells and scored the frequency of cell death in these cultures. We prepared human trophoblastic cells from term placentas removed by C-section and placed them in culture for 48 h before introducing the lymphoid cells. We added Jurkat cells, a CD3 + lymphoid cell line, or purified T cells from human blood to the cultured trophoblasts and monitored apoptosis by electron microscopy and flow cytometry after TUNEL or annexin V labelling. The frequency of cell death in the CD3 + cell population was higher when the lymphoid cells were cocultured with trophoblastic cells than when they were cultured alone. This frequency increased with time but was reduced when anti-CD95-L antibodies were added to the culture medium. Cell death was less frequent in the lymphoid cell population when trophoblasts were replaced with human fibroblasts not expressing CD95-L.
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Affiliation(s)
- B Coumans
- Institute of Human Histology, University of Liège, Belgium
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de Borman B, Lakaye B, Minet A, Zorzi W, Vergnes M, Marescaux C, Grisar T. Expression of mRNA encoding alpha1E and alpha1G subunit in the brain of a rat model of absence epilepsy. Neuroreport 1999; 10:569-74. [PMID: 10208591 DOI: 10.1097/00001756-199902250-00023] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Low voltage-activated calcium channels are thought to play a key role in the generation of spike and waves discharges characteristic of absence epilepsy. Therefore, the expression level of mRNA encoding calcium channel alpha1E and alpha1G subunits was measured in the brain of genetic absence epilepsy rats from Strasbourg (GAERS). Using quantitative RT-PCR and in situ hybridization, no difference was found in alpha1G mRNA expression between GAERS and control animals, while a decreased expression of alpha1E was seen in the cerebellum and the brain stem of the GAERS. This phenomenon was not observed in young animals when the epileptic phenotype is not expressed.
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Affiliation(s)
- B de Borman
- Laboratory of Biochemistry, Research Group in Neurochemistry, University of Liege, Belgium
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Massidda O, Dardenne O, Whalen MB, Zorzi W, Coyette J, Shockman GD, Daneo-Moore L. The PBP 5 synthesis repressor (psr) gene of Enterococcus hirae ATCC 9790 is substantially longer than previously reported. FEMS Microbiol Lett 1998; 166:355-60. [PMID: 9770293 DOI: 10.1111/j.1574-6968.1998.tb13912.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
A reexamination of the nucleotide sequence of the psr gene of Enterococcus hirae revealed the presence of two additional nucleotides at residues 1190 and 1191. As a result, instead of a stop codon after 148 aa, the psr gene product would contain 293 aa residues. The revised size of the gene product was confirmed by subsequently cloning and expressing the psr gene in Escherichia coli. The derived amino acid sequence of the revised psr gene product was found to be similar to several other proteins in the combined GenBank/EMBL database. The protein products of some of these genes are thought to play regulatory role(s) in exo or capsular polysaccharide synthesis and/or in cell wall metabolism. All the putative homologs of the revised Psr appear to have a putative membrane-anchoring domain at their N-termini. Amino acid blocks with high degrees of similarity have been identified in the aligned sequences, and it is suggested that these common motifs could be of structural or functional importance.
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Affiliation(s)
- O Massidda
- Department of Microbiology and Immunology, Temple University School of Medicine, Philadelphia, PA 19140, USA.
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Abstract
Tolerance of the fetal allograft enables the human conceptus to implant itself into the maternal uterus and survive and grow there. This tolerance phenomenon remains largely obscure, notably because it appears to be controlled by multiple mechanisms. CD95 ligand (CD95-L), which can trigger death of CD95-positive cells by apoptosis, may participate in inducing anti-fetus-sensitized CD95-positive T lymphocytes to enter apoptosis. Using immunohistochemistry (first trimester and term placentae), FACS assays (term placenta) and RT-PCR assays (term placenta), the presence of CD95-L protein and mRNA has been shown in crude placental tissue preparations and isolated placental cells. Among the latter, CD95-L expression was detected in trophoblastic cells, fetal blood cells (mRNA only) and also the Hofbauer macrophages. No CD95-L was detected in fibroblasts or fetal endothelial cells. Thus trophoblastic cells, Hofbauer macrophages, and perhaps also fetal blood cells could form a sequential barrier blocking maternal activated defence cells bearing CD95 molecules.
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Affiliation(s)
- W Zorzi
- Institute of Human Histology, University of Liège, Belgium
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Lakaye B, Minet A, Zorzi W, Grisar T. Cloning of the rat brain cDNA encoding for the SLC-1 G protein-coupled receptor reveals the presence of an intron in the gene. Biochim Biophys Acta 1998; 1401:216-20. [PMID: 9531978 DOI: 10.1016/s0167-4889(97)00135-3] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In order to isolate new G protein-coupled receptors expressed in the cerebral cortex, a set of degenerate oligonucleotides corresponding to the third and seventh transmembrane segment were synthetized. Their use in PCR on rat brain cortex mRNA amplified several cDNA fragments. One of them, a 526 bp sequence, encoded for what was at that time an unknown G protein-coupled receptor. An oligonucleotide derived from the sequence was then used as a probe to isolate the receptor cDNA from a rat brain cDNA library. It encodes for a 353aa protein with seven transmembrane segments, three consensus N-glycosylation sites at the amino terminus and several potential phosphorylation sites in the intracellular loops. This protein shares 91% overall identity with a recently cloned human somatostatin-like receptor of 402aa named SLC-1. This suggests that we have cloned the rat orthologue of the human SLC-1. However, the extracellular N-terminus of the human receptor is 49 amino acids longer and shows 50% identity with the rat one. Because the human sequence was deduced from genomic DNA, we suspected the presence of an intron in the gene. This was confirmed by PCR using primers spanning the intron. On the basis of the sequence of a 128 kb fragment of chromosome 22 encompassing the SLC-1 gene, we were able to deduce a corrected amino acids sequence for the human receptor. So both rat and human SLC-1 receptors are 353aa long, with three consensus N-glycosylation sites. They share 96% identity at the amino acid level and are encoded by a gene containing one intron in the coding sequence.
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Affiliation(s)
- B Lakaye
- Laboratory of Neurochemistry University of Liège, Belgium.
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Thellin O, Coumans B, Zorzi W, Barnard R, Hennen G, Heinen E, Igout A. Expression of growth hormone receptors by lymphocyte subpopulations in the human tonsil. Dev Immunol 1998; 6:295-304. [PMID: 9814603 PMCID: PMC2276034 DOI: 10.1155/1998/85209] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The ability of human tonsillar lymphoid cells to express growth hormone receptor (hGH-N-R) was analyzed by flow cytometry. FITC-coupled recombinant human growth hormone (hGH-N) was used to reveal the receptors, in combination with phenotype markers. Unlike T cells, tonsillar B cells constitutively express the hGH-N receptor. Quiescent cells separated from activated cells by Percoll-gradient centrifugation bear fewer receptors than activated ones. Activated T cells express hGH-N-R, but the typical germinal centre CD4+ CD57+ T cells do not. These latter thus appear not to be fully activated. Inside the lymph follicles, the germinal centre CD38+ B-cell population and the mantle-zone CD39+ B-cell population display similar levels of hGH-N-R expression, but receptor density is lower on dividing dark-zone CD38+ CD10+ B cells. Different lymphoid-cell populations thus differ markedly in their ability to express the growth hormone receptor, in relation notably to their activation status. This highlights the link between the neuroendocrine system and the active immune defense.
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Affiliation(s)
- O Thellin
- Laboratory of Biochemistry/Endocrinology, University of Liège, Belgium
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Zorzi W, Zhou XY, Dardenne O, Lamotte J, Raze D, Pierre J, Gutmann L, Coyette J. Structure of the low-affinity penicillin-binding protein 5 PBP5fm in wild-type and highly penicillin-resistant strains of Enterococcus faecium. J Bacteriol 1996; 178:4948-57. [PMID: 8759860 PMCID: PMC178279 DOI: 10.1128/jb.178.16.4948-4957.1996] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Among its penicillin-binding proteins (PBPs), Enterococcus faecium possesses a low-affinity PBP5, PBP5fm, which is the main target involved in beta-lactam resistance. A 7.7-kb EcoRI chromosomal fragment of E. faecium D63r containing the pbp5fm gene was cloned and sequenced. Two open reading frames (ORFs) were found. A 2,037-bp ORF encoded the deduced 73.8-kDa PBP5fm, the amino acid sequences of which were, respectively, 99.8, 78.5, and 62% homologous to those of the low-affinity plasmid-encoded PBP3r of Enterococcus hirae S185r and the chromosome-encoded PBP5 of E. hirae R40 and Enterococcus faecalis 56R. A second 597-bp ORF, designated psrfm, was found 2.3 kb upstream of pbp5fm. It appeared to be 285 bp shorter than and 74% homologous with the regulatory gene psr of E. hirae ATCC 9790. Different clinical isolates of E. faecium, for which a wide range of benzylpenicillin MICs were observed, showed that the increases in MICs were related to two mechanisms. For some strains of intermediate resistance (MICs of 16 to 64 micrograms/ml), the increased level of resistance could be explained by the presence of larger quantities of PBP5fm which had an affinity for benzylpenicillin (second-order rate constant of protein acylation [k+2/K] values of 17 to 25 M(-1) s(-1)) that remained unchanged. For the two most highly resistant strains, EFM-1 (MIC, 90 micrograms/ml) and H80721 (MIC, 512 micrograms/ml), the resistance was related to different amino acid substitutions yielding very-low-affinity PBP5fm variants (k+2/K < or = 1.5 M(-1) s(-1)) which were synthesized in small quantities. More specifically, it appeared, with a three-dimensional model of the C-terminal domain of PBP5fm, that the substitutions of Met-485, located in the third position after the conserved SDN triad, by Thr in EFM-1 and by Ala in H80721 were the most likely cause of the decreasing affinity of PBP5fm observed in these strains.
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Affiliation(s)
- W Zorzi
- Centre d'Ingénierie des Protéines, Université de Liège, Sart Tilman, Belgium
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Granier B, Jamin M, Adam M, Galleni M, Lakaye B, Zorzi W, Grandchamps J, Wilkin JM, Fraipont C, Joris B. Serine-type D-Ala-D-Ala peptidases and penicillin-binding proteins. Methods Enzymol 1994; 244:249-66. [PMID: 7845213 DOI: 10.1016/0076-6879(94)44021-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- B Granier
- Centre d'Ingénierie de Protéines, Université de Liège, Sart Tilman, Belgium
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Adam M, Damblon C, Jamin M, Zorzi W, Dusart V, Galleni M, el Kharroubi A, Piras G, Spratt BG, Keck W. Acyltransferase activities of the high-molecular-mass essential penicillin-binding proteins. Biochem J 1991; 279 ( Pt 2):601-4. [PMID: 1953655 PMCID: PMC1151646 DOI: 10.1042/bj2790601] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The high-molecular-mass penicillin-binding proteins (HMM-PBPs), present in the cytoplasmic membranes of all eubacteria, are involved in important physiological events such as cell elongation, septation or shape determination. Up to now it has, however, been very difficult or impossible to study the catalytic properties of the HMM-PBPs in vitro. With simple substrates, we could demonstrate that several of these proteins could catalyse the hydrolysis of some thioesters or the transfer of their acyl moiety on the amino group of a suitable acceptor nucleophile. Many of the acyl-donor substrates were hippuric acid or benzoyl-D-alanine derivatives, and their spectroscopic properties enabled a direct monitoring of the enzymic reaction. In their presence, the binding of radioactive penicillin to the PBPs was also inhibited.
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Affiliation(s)
- M Adam
- Centre d'Ingénierie des Protéines, Université de Liège, Belgium
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