Cooperative binding of estrogen receptor to imperfect estrogen-responsive DNA elements correlates with their synergistic hormone-dependent enhancer activity.

The Xenopus vitellogenin (vit) gene B1 estrogen-inducible enhancer is formed by two closely adjacent 13 bp imperfect palindromic estrogen-responsive elements (EREs), i.e. ERE-2 and ERE-1, having one and two base substitutions respectively, when compared to the perfect palindromic consensus ERE (GGTCANNNTGACC). Gene transfer experiments indicate that these degenerated elements, on their own, have a low or no regulatory capacity at all, but in vivo act together synergistically to confer high receptor- and hormone-dependent transcription activation to the heterologous HSV thymidine kinase promoter. Thus, the DNA region upstream of the vitB1 gene comprising these two imperfect EREs separated by 7 bp, was called the vitB1 estrogen-responsive unit (vitB1 ERU). Using in vitro protein-DNA interaction techniques, we demonstrate that estrogen receptor dimers bind cooperatively to the imperfect EREs of the vitB1 ERU. Binding of a first receptor dimer to the more conserved ERE-2 increases approximately 4- to 8-fold the binding affinity of the receptor to the adjacent less conserved ERE-1. Thus, we suggest that the observed synergistic estrogen-dependent transcription activation conferred by the pair of hormone-responsive DNA elements of the vit B1 ERU is the result of cooperative binding of two estrogen receptor dimers to these two adjacent imperfect EREs.

Mutations in the SPARC-Related Modular Calcium-Binding Protein 1 Gene, SMOC1, Cause Waardenburg Anophthalmia Syndrome.

Waardenburg anophthalmia syndrome, also known as microphthalmia with limb anomalies, ophthalmoacromelic syndrome, and anophthalmia-syndactyly, is a rare autosomal-recessive developmental disorder that has been mapped to 10p11.23. Here we show that this disease is heterogeneous by reporting on a consanguineous family, not linked to the 10p11.23 locus, whose two affected children have a homozygous mutation in SMOC1. Knockdown experiments of the zebrafish smoc1 revealed that smoc1 is important in eye development and that it is expressed in many organs, including brain and somites.

Immunocytochemical localization of the glucose transporter 2 (GLUT2) in the adult rat brain. II. Electron microscopic study.

Following a former immunohistochemical study in the rat brain [Arluison, M., Quignon, M., Nguyen, P., Thorens, B., Leloup, C., Penicaud, L. Distribution and anatomical localization of the glucose transporter 2 (GLUT2) in the adult rat brain. I. Immunohistochemical study. J. Chem. Neuroanat., in press], we have analyzed the ultrastructural localization of GLUT2 in representative and/or critical areas of the forebrain and hindbrain. In agreement with previous results, we observe few oligodendrocyte and astrocyte cell bodies discretely labeled for GLUT2 in large myelinated fibre bundles and most brain areas examined, whereas the reactive glial processes are more numerous and often localized in the vicinity of nerve terminals and/or dendrites or dendritic spines forming synaptic contacts. Only some of them appear closely bound to unlabeled nerve cell bodies and dendrites. Furthermore, the nerve cell bodies prominently immunostained for GLUT2 are scarce in the brain nuclei examined, whereas the labeled dendrites and dendritic spines are relatively numerous and frequently engaged in synaptic junctions. In conformity with the observation of GLUT2-immunoreactive rings at the periphery of numerous nerve cell bodies in various brain areas (see previous paper), we report here that some neuronal perikarya of the dorsal endopiriform nucleus/perirhinal cortex exhibit some patches of immunostaining just below the plasma membrane. However, the presence of many GLUT2-immunoreactive nerve terminals and/or astrocyte processes, some of them being occasionally attached to nerve cell bodies and dendrites, could also explain the pericellular labeling observed. The results here reported support the idea that GLUT2 may be expressed by some cerebral neurones possibly involved in glucose sensing, as previously discussed. However, it is also possible that this transporter participate in the regulation of neurotransmitter release and, perhaps, in the release of glucose by glial cells.

Binding of d-methadone, l-methadone, and dl-methadone to proteins in plasma of healthy volunteers: role of the variants of alpha 1-acid glycoprotein.

The plasma concentrations of alpha 1-acid glycoprotein (AAG), albumin, triglycerides, cholesterol, and total proteins, as well as the plasma binding of racemic, d-methadone, and l-methadone were measured in 45 healthy subjects. The AAG phenotypes and the concentrations of AAG variants were also determined. The measured free fractions for racemic, d-methadone, and l-methadone were, respectively, 12.7% +/- 3.3%, 10.0% +/- 2.9%, and 14.2% +/- 3.2% (mean +/- SD). A significant correlation was obtained between the binding ratio (B/F) for dl-methadone and the total AAG concentration (r = 0.724; p less than 0.001). A multiple stepwise regression analysis showed that AAG was the main explanatory variable for the binding of the racemate. When concentrations of AAG variants were considered, a significant correlation was obtained between the binding ratio of dl-methadone and orosomucoid2 A concentration (r = 0.715; p less than 0.001), a weak correlation between dl-methadone and orosomucoid1 S concentration (r = 0.494; p less than 0.001), and no correlation between dl-methadone and orosomucoid1 F1 concentration (r = 0.049; not significant). Similar findings were obtained with the enantiomers. This study shows the importance of considering not only total AAG but also concentrations of AAG variants when measuring the binding of methadone and possibly of other drugs in plasma.

PPAR beta a player in astrocyte metabolism and morphology

AbstractPPARP is a nuclear receptor responding in vivo to several free fatty acids, and implicated in cell metabolism, differentiation and survival. PPARp is ubiquitously expressed but shows high expression in the developing and adult brain. PPARp is expressed in different cell types such as neurons and astrocytes, where it might play a role in metabolism. To study this nuclear receptor the laboratory engineered a PPARP -/- mouse model. The aim of my PhD was to dissect the role of PPARP in astrocytes.Experiments in primary culture revealed that cortical astrocytes from PPARP -/- mouse have an impaired energetic metabolism. Unstimulated PPARP -/- astrocytes exhibit a 30% diminution in glucose uptake, correlating to a 30% decrease in lactate release and intracellular glucose. After acute stimulation by D- aspartate mimicking glutamate exposure, both WT and -/- astrocytes up-regulate their metabolism to respond to the increasing energy needed (ATP) for glutamate uptake. According to the Astrocyte Neuron Lactate Shuttle Hypothesis (ANLSH), the ratio between glucose uptake/ lactate release is 1. However, stimulated PPARp -/- astrocytes display a higher increase in lactate release than glucose uptake which remains lower than in WT. The extra glucose equivalents could come from the degradation of intra cellular glycogen stores, which indeed decrease in PPARP -/- cells upon stimulation. Lower glucose metabolism correlates with a decreased acute glutamate uptake in PPARP -/- astrocytes. Reciprocally, we also observed an increase of glutamate uptake and ATP production after treatment of WT astrocytes with a PPARp agonist. Glutamate transporter protein expression is not affected. However, their trafficking and localization might be altered as PPARp -/- astrocytes have higher cholesterol levels, which may also affect proper transporter structure in the membrane.Metabolism, transporter localization and cholesterol levels are respectively linked to cell mobility, cell cytoskeleton and cellular membrane composition. All three functions are important in astrocytes to in vivo acquire star shaped morphology, in a process known as stellation. PPARP -/- astrocytes showed an impaired acquired stellation in presence of neurons or chemical stimuli, as well as more actin stress fibers and cell adhesion structures. While non stellation of astrocytes is mainly an in vitro phenomenon, it reveals PPARp -/- primary astrocytes inability to respond to different exterior stimuli. These morphological phenotypes correlate with a slower migration in cell culture wound healing assays.This thesis work demonstrates that PPARp is implicated in cortical astrocyte glucose metabolism. PPARp absence leads to an unusual intracellular glycogen use. Added to the effect on acute glutamate uptake and astrocyte migration, PPARp could be an interesting target for neuroprotection therapies.RésuméPPARP est un récepteur nucléaire qui a pour ligands naturels certains acides gras libres. Il est impliqué dans le métabolisme, la différentiation et la survie des cellules. PPARP est ubiquitaire, et a une expression élevée dans le cerveau en développement ainsi qu'adulte. PPARp est exprimé dans différents types cellulaires tels que les neurones et les astrocytes, où il régule potentiellement leurs métabolismes. Pour étudier ce récepteur nucléaire, le laboratoire a créé un modèle de souris PPARp -/-. L'objectif de ma thèse est de comprendre le rôle de PPARp dans les astrocytes.Les expériences montrent un défaut du métabolisme énergétique dans les astrocytes corticaux primaires tirés de souris PPARp -/-. Sans stimulation, l'entrée du glucose dans les astrocytes PPARP -/- est diminuée de 30% ce qui correspond à une diminution de 30% du relargage du lactate. Après stimulation par du D-Aspartate qui mime une exposition au glutamate, les astrocytes WT et -/- augmentent leur métabolisme en réponse à la demande accrue en énergie (ATP) due à l'entrée du glutamate. D'après l'Astrocyte Neuron Lactate Shuttle Hypothesis (ANLSH), le ratio entre le glucose entrant et le lactate sortant est de 1. Cependant le relargage du lactate dans les astrocytes PPARP-/- est plus élevé que l'entrée du glucose. L'apport supplémentaire de glucose transformé en lactate pourrait provenir de la dégradation des stocks de glycogène intracellulaire, qui sont partiellement diminués après stimulation dans les cellules PPARP -/-. Un métabolisme plus faible du glucose corrèle avec une réduction de l'import du glutamate dans les astrocytes PPARp -/-. Réciproquement, nous observons une augmentation de l'import du glutamate et de la production d'ATP après traitement avec l'agoniste pour PPARp. Bien que l'expression des transporteurs de glutamate ne soit pas affectée, nous ne pouvons pas exclure que leur localisation et leur structure soient altérées du fait du niveau élevé de cholestérol dans les astrocytes PPARp -/-.Le métabolisme, la localisation des transporteurs et le niveau de cholestérol sont tous liés au cytosquelette, à la mobilité, et à la composition des membranes cellulaires. Toutes ces fonctions sont importantes pour les astrocytes pour acquérir leur morphologie in vivo. Les astrocytes PPARP -/- présentent un défaut de stellation, aussi bien en présence de neurones que de stimuli chimiques, ainsi qu'un plus grand nombre de fibres de stress (actine) et de structures d'adhésion cellulaire. Bien que les astrocytes non stellaires soient principalement observés in vitro, le défaut de stellation des astrocytes primaires PPARp -/- indique une incapacité à répondre aux différents stimuli extérieurs. Ces phénotypes morphologiques corrèlent avec une migration plus lente en cas de lésion de la culture.Ce travail de thèse a permis de démontrer l'implication de PPARP dans le métabolisme du glucose des astrocytes corticaux. L'absence de ce récepteur nucléaire amène à l'utilisation du glucose intracellulaire, auquel s'ajoutent les effets sur l'import du glutamate et la migration des astrocytes. PPARp aurait des effets neuroprotecteurs, et de ce fait pourrait être utilisé à des fins thérapeutiques.

Cross-immunoreactivity between anti-potato apyrase antibodies and mammalian ATP diphosphohydrolases: potential use of the vegetal protein in experimental schistosomiasis

We have previously showed that Schistosoma mansoni ATP-diphosphohydrolase and Solanum tuberosum potato apyrase share epitopes and the vegetable protein has immunostimulatory properties. Here, it was verified the in situ cross-immunoreactivity between mice NTPDases and anti-potato apyrase antibodies produced in rabbits, using confocal microscopy. Liver samples were taken from Swiss Webster mouse 8 weeks after infection with S. mansoni cercariae, and anti-potato apyrase and TRITC-conjugated anti-rabbit IgG antibody were tested on cryostat sections. The results showed that S. mansoni egg ATP diphosphohydrolase isoforms, developed by anti-potato apyrase, are expressed in miracidial and egg structures, and not in granulomatous cells and hepatic structures (hepatocytes, bile ducts, and blood vessels). Therefore, purified potato apyrase when inoculated in rabbit generates polyclonal sera containing anti-apyrase antibodies that are capable of recognizing specifically S. mansoni ATP diphosphohydrolase epitopes, but not proteins from mammalian tissues, suggesting that autoantibodies are not induced during potato apyrase immunization. A phylogenetic tree obtained for the NTPDase family showed that potato apyrase had lower homology with mammalian NTPDases 1-4, 7, and 8. Further analysis of potato apyrase epitopes could implement their potential use in schistosomiasis experimental models.

Improving binding affinity and stability of peptide ligands by substituting glycines with D-amino acids.

Improving the binding affinity and/or stability of peptide ligands often requires testing of large numbers of variants to identify beneficial mutations. Herein we propose a type of mutation that promises a high success rate. In a bicyclic peptide inhibitor of the cancer-related protease urokinase-type plasminogen activator (uPA), we observed a glycine residue that has a positive ϕ dihedral angle when bound to the target. We hypothesized that replacing it with a D-amino acid, which favors positive ϕ angles, could enhance the binding affinity and/or proteolytic resistance. Mutation of this specific glycine to D-serine in the bicyclic peptide indeed improved inhibitory activity (1.75-fold) and stability (fourfold). X-ray-structure analysis of the inhibitors in complex with uPA showed that the peptide backbone conformation was conserved. Analysis of known cyclic peptide ligands showed that glycine is one of the most frequent amino acids, and that glycines with positive ϕ angles are found in many protein-bound peptides. These results suggest that the glycine-to-D-amino acid mutagenesis strategy could be broadly applied.

Multiple adenosine 3',5'-cyclic [corrected] monophosphate response element DNA-binding proteins generated by gene diversification and alternative exon splicing.

The protein sequence deduced from the open reading frame of a human placental cDNA encoding a cAMP-responsive enhancer (CRE)-binding protein (CREB-327) has structural features characteristic of several other transcriptional transactivator proteins including jun, fos, C/EBP, myc, and CRE-BP1. Results of Southwestern analysis of nuclear extracts from several different cell lines show that there are multiple CRE-binding proteins, which vary in size in cell lines derived from different tissues and animal species. To examine the molecular diversity of CREB-327 and related proteins at the nucleic acid level, we used labeled cDNAs from human placenta that encode two different CRE-binding proteins (CREB-327 and CRE-BP1) to probe Northern and Southern blots. Both probes hybridized to multiple fragments on Southern blots of genomic DNA from various species. Alternatively, when a human placental c-jun probe was hybridized to the same blot, a single fragment was detected in most cases, consistent with the intronless nature of the human c-jun gene. The CREB-327 probe hybridized to multiple mRNAs, derived from human placenta, ranging in size from 2-9 kilobases. In contrast, the CRE-BP1 probe identified a single 4-kilobase mRNA. Sequence analyses of several overlapping human genomic cosmid clones containing CREB-327 sequences in conjunction with polymerase chain reaction indicates that the CREB-327/341 cDNAs are composed of at least eight or nine exons, and analyses of human placental cDNAs provide direct evidence for at least one alternatively spliced exon. Analyses of mouse/hamster-human hybridoma DNAs by Southern blotting and polymerase chain reaction localizes the CREB-327/341 gene to human chromosome 2. The results indicate that there is a dichotomy of CREB-like proteins, those that are related by overall structure and DNA-binding specificity as well as those that are related by close similarities of primary sequences.

Heterogeneous secretion of individual B cells in response to D-glucose and to nonglucidic nutrient secretagogues.

We used a hemolytic plaque assay for insulin to determine whether the same pancreatic B cells respond to D-glucose, 2-amino-bicyclo[2,2,1]heptane-2-carboxylic acid (BCH) and the association of this nonmetabolized analogue of L-leucine with either the monomethyl ester of succinic acid (SME) or the dimethyl ester of L-glutamic acid (GME). During a 30-min incubation in the absence of D-glucose, BCH alone (5 mM) had no effect on insulin release. In contrast, the combination of BCH with either SME (10 mM) or GME (3 mM) stimulated insulin release to the same extent observed in the sole presence of 16.7 mM D-glucose. The effects of BCH plus SME and BCH plus GME on both percentage of secreting B cells and total insulin output were little affected in the presence of D-glucose concentrations ranging from 0 to 16.7 mM. Varying the concentration of SME from 2 to 10 mM also did not influence these effects. In other experiments, the very same B cells were first exposed 45 min to 16.7 mM D-glucose, then incubated 45 min in the presence of only BCH and SME. Under these conditions, most (80.3 +/- 2.5%) of the cells contributing to insulin release did so during both incubation periods. Furthermore, virtually all cells responding to BCH and SME during the second incubation corresponded to cells also responsive to D-glucose during the first incubation. Similar observations were made when the sequence of the two incubations was reversed.(ABSTRACT TRUNCATED AT 250 WORDS)

Polymorphism in the promoter region of the mannose-binding lectin gene among human T-cell lymphotropic virus infected subjects

The present study investigated the frequency of the mutations at positions -550 and -221 of the mannose-binding lectin (MBL) gene in a sample of 75 human T-cell lymphotropic virus (HTLV) infected patients and 96 HTLV seronegative controls, in order to evaluate the occurrence of a possible association between the polymorphism and HTLV infection. A sequence specific primer-polymerase chain reaction was used for discrimination of the polymorphism. The analysis of allele frequencies at position -550 did not show any significant differences between HTLV infected group and controls, but there was a significant difference at position -221. The comparative analysis of haplotypes frequencies were not significant, but the genotype frequencies between the two groups, revealed a higher prevalence of genotype LYLX (25.3%), associated with medium and low MBL serum levels among HTLV infected subjects. The odds ratio estimation demonstrated that the presence of genotype LYLX was associated with an increased risk of HTLV infection (p = 0.0096; 1.38 < IC95% < 7.7605). There was no association between proviral load and the promoter polymorphism, but when promoter and exon 1 mutations were matched, it was possible to identify a significant higher proviral load among HTLV infected individuals carrying haplotypes correlated to low serum levels of MBL. The present study shows that the polymorphism in the promoter region of the MBL gene may be a genetic marker associated with HTLV infection, and emphasizes the need for further studies to determinate if the present polymorphism have any impact on diseases linked to HTLV infection.

Access of extracellular cations to their binding sites in Na,K-ATPase: role of the second extracellular loop of the alpha subunit.

Na,K-ATPase, the main active transport system for monovalent cations in animal cells, is responsible for maintaining Na(+) and K(+) gradients across the plasma membrane. During its transport cycle it binds three cytoplasmic Na(+) ions and releases them on the extracellular side of the membrane, and then binds two extracellular K(+) ions and releases them into the cytoplasm. The fourth, fifth, and sixth transmembrane helices of the alpha subunit of Na,K-ATPase are known to be involved in Na(+) and K(+) binding sites, but the gating mechanisms that control the access of these ions to their binding sites are not yet fully understood. We have focused on the second extracellular loop linking transmembrane segments 3 and 4 and attempted to determine its role in gating. We replaced 13 residues of this loop in the rat alpha1 subunit, from E314 to G326, by cysteine, and then studied the function of these mutants using electrophysiological techniques. We analyzed the results using a structural model obtained by homology with SERCA, and ab initio calculations for the second extracellular loop. Four mutants were markedly modified by the sulfhydryl reagent MTSET, and we investigated them in detail. The substituted cysteines were more readily accessible to MTSET in the E1 conformation for the Y315C, W317C, and I322C mutants. Mutations or derivatization of the substituted cysteines in the second extracellular loop resulted in major increases in the apparent affinity for extracellular K(+), and this was associated with a reduction in the maximum activity. The changes produced by the E314C mutation were reversed by MTSET treatment. In the W317C and I322C mutants, MTSET also induced a moderate shift of the E1/E2 equilibrium towards the E1(Na) conformation under Na/Na exchange conditions. These findings indicate that the second extracellular loop must be functionally linked to the gating mechanism that controls the access of K(+) to its binding site.

Oral epidermal growth factor receptor tyrosine kinase inhibitors for the treatment of non-small cell lung cancer: comparative pharmacokinetics and drug-drug interactions.

The development of orally active small molecule inhibitors of the epidermal growth factor receptor (EGFR) has led to new treatment options for non-small cell lung cancer (NSCLC). Patients with activating mutations of the EGFR gene show sensitivity to, and clinical benefit from, treatment with EGFR tyrosine kinase inhibitors (EGFR-TKls). First generation reversible ATP-competitive EGFR-TKls, gefitinib and erlotinib, are effective as first, second-line or maintenance therapy. Despite initial benefit, most patients develop resistance within a year, 50-60% of cases being related to the appearance of a T790M gatekeeper mutation. Newer, irreversible EGFR-TKls - afatinib and dacomitinib - covalently bind to and inhibit multiple receptors in the ErbB family (EGFR, HER2 and HER4). These agents have been mainly evaluated for first-line treatment but also in the setting of acquired resistance to first-generation EGFR-TKls. Afatinib is the first ErbB family blocker approved for patients with NSCLC with activating EGFR mutations; dacomitinib is in late stage clinical development. Mutant-selective EGFR inhibitors (AZD9291, CO-1686, HM61713) that specifically target the T790M resistance mutation are in early development. The EGFR-TKIs differ in their spectrum of target kinases, reversibility of binding to EGFR receptor, pharmacokinetics and potential for drug-drug interactions, as discussed in this review. For the clinician, these differences are relevant in the setting of polymedicated patients with NSCLC, as well as from the perspective of innovative anticancer drug combination strategies.

Low Mannan-binding lectin serum levels are associated with complicated Crohn's disease and reactivity to oligomannan (ASCA).

OBJECTIVES: Mannan-binding lectin (MBL) acts as a pattern-recognition molecule directed against oligomannan, which is part of the cell wall of yeasts and various bacteria. We have previously shown an association between MBL deficiency and anti-Saccharomyces cerevisiae mannan antibody (ASCA) positivity. This study aims at evaluating whether MBL deficiency is associated with distinct Crohn's disease (CD) phenotypes. METHODS: Serum concentrations of MBL and ASCA were measured using ELISA (enzyme-linked immunosorbent assay) in 427 patients with CD, 70 with ulcerative colitis, and 76 healthy controls. CD phenotypes were grouped according to the Montreal Classification as follows: non-stricturing, non-penetrating (B1, n=182), stricturing (B2, n=113), penetrating (B3, n=67), and perianal disease (p, n=65). MBL was classified as deficient (<100 ng/ml), low (100-500 ng/ml), and normal (500 ng/ml). RESULTS: Mean MBL was lower in B2 and B3 CD patients (1,503+/-1,358 ng/ml) compared with that in B1 phenotypes (1,909+/-1,392 ng/ml, P=0.013). B2 and B3 patients more frequently had low or deficient MBL and ASCA positivity compared with B1 patients (P=0.004 and P<0.001). Mean MBL was lower in ASCA-positive CD patients (1,562+/-1,319 ng/ml) compared with that in ASCA-negative CD patients (1,871+/-1,320 ng/ml, P=0.038). In multivariate logistic regression modeling, low or deficient MBL was associated significantly with B1 (negative association), complicated disease (B2+B3), and ASCA. MBL levels did not correlate with disease duration. CONCLUSIONS: Low or deficient MBL serum levels are significantly associated with complicated (stricturing and penetrating) CD phenotypes but are negatively associated with the non-stricturing, non-penetrating group. Furthermore, CD patients with low or deficient MBL are significantly more often ASCA positive, possibly reflecting delayed clearance of oligomannan-containing microorganisms by the innate immune system in the absence of MBL.

Characterization of polymorphisms in the mannose-binding lectin gene promoter among human immunodeficiency virus 1 infected subjects

The present study investigated the prevalence of mutations in the -550 (H/L) and -221 (X/Y) mannose-binding lectin (MBL) gene promoter regions and their impact on infection by human immunodeficiency virus 1 (HIV-1) in a population of 128 HIV-1 seropositive and 97 seronegative patients. The allele identification was performed through the sequence-specific primer polymerase chain reaction method, using primer sequences specific to each polymorphism. The evolution of the infection was evaluated through CD4+ T-lymphocyte counts and plasma viral load. The allele and haplotype frequencies among HIV-1-infected patients and seronegative healthy control patients did not show significant differences. CD4+ T-lymphocyte counts showed lower levels among seropositive patients carrying haplotypes LY, LX and HX, as compared to those carrying the HY haplotype. Mean plasma viral load was higher among seropositive patients with haplotypes LY, LX and HX than among those carrying the HY haplotype. When promoter and exon 1 mutations were matched, it was possible to identify a significantly higher viral load among HIV-1 infected individuals carrying haplotypes correlated to low serum levels of MBL. The current study shows that haplotypes related to medium and low MBL serum levels might directly influence the evolution of viral progression in patients. Therefore, it is suggested that the identification of haplotypes within the promoter region of the MBL gene among HIV-1 infected persons should be further evaluated as a prognostic tool for AIDS progression.

The redox potential interferes with the expression of laminin binding molecules in Bacteroides fragilis

The Bacteroides fragilis ATCC strain was grown in a synthetic media with contrasting redox potential (Eh) levels [reduced (-60 mV) or oxidised (+100mV)] and their adhesion capacity to extracellular matrix components was evaluated. The strain was capable of adhering to laminin, fibronectin, fibronectin + heparan sulphate and heparan sulphate. A stronger adherence to laminin after growing the strain under oxidising conditions was verified. Electron microscopy using ruthenium red showed a heterogeneous population under this condition. Dot-blotting analyses confirmed stronger laminin recognition by outer membrane proteins of cells cultured at a higher Eh. Using a laminin affinity column, several putative laminin binding proteins obtained from the cultures kept under oxidising (60 kDa, 36 kDa, 25 kDa and 15 kDa) and reducing (60 kDa) conditions could be detected. Our results show that the expression of B. fragilis surface components that recognise laminin are influenced by Eh variations.