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A Barre

Publications and source records attributed to A Barre.

50 records · Page 3Linked to original sources
PubMed1996

Structure-function relationship of monocot mannose-binding lectins.

The monocot mannose-binding lectins are an extended superfamily of structurally and evolutionarily related proteins, which until now have been isolated from species of the Amaryllidaceae, Alliaceae, Araceae, Orchidaceae, and Liliaceae. To explain the obvious differences in biological activities, the structure-function relationships of the monocot mannose-binding lectins were studied by a combination of glycan-binding studies and molecular modeling using the deduced amino acid sequences of the currently known lectins. Molecular modeling indicated that the number of active mannose-binding sites per monomer varies between three and zero. Since the number of binding sites is fairly well correlated with the binding activity measured by surface plasmon resonance, and is also in good agreement with the results of previous studies of the biological activities of the mannose-binding lectins, molecular modeling is of great value for predicting which lectins are best suited for a particular application.

Asialoglycoproteins↗
PubMed1995

The seed lectins of black locust (Robinia pseudoacacia) are encoded by two genes which differ from the bark lectin genes.

Two lectins were isolated from Robinia pseudoacacia (black locust) seeds using affinity chromatography on fetuin-agarose, and ion exchange chromatography on a Neobar CS column. The first lectin, R. pseudoacacia seed agglutinin I, referred to as RPsAI, is a homotetramer of four 34 kDa subunits whereas the second lectin, referred to as RPsAII, is composed of four 29 kDa polypeptides. cDNA clones encoding the polypeptides of RPsAI and RPsAII were isolated and their sequences were determined. Both polypeptides are translated from mRNAs of ca. 1.2 kb encoding a precursor carrying a signal peptide. Alignment of the deduced amino acid sequences of the different clones indicates that the 34 and 29 kDa seed lectin polypeptides show 95% sequence identity. In spite of this striking homology, the 29 kDa polypeptide has only one putative glycosylation site whereas the 34 kDa subunit has four of these sites. Carbohydrate analysis revealed that the 34 kDa possesses three carbohydrate chains whereas the 29 kDa polypeptide is only partially glycosylated at one site. A comparison of the deduced amino acid sequences of the two seed and three bark lectin polypeptides demonstrated unambiguously that they are encoded by different genes. This implies that five different genes are involved in the control of the expression of the lectins in black locust.

Amino Acid Sequence↗
PubMed1995

A lectin and a lectin-related protein are the two most prominent proteins in the bark of yellow wood (Cladrastis lutea).

Using a combination of cDNA cloning and protein purification it is demonstrated that bark of yellow wood (Cladrastis lutea) contains two mannose/glucose binding lectins and a lectin-related protein which is devoid of agglutination activity. One of the lectins (CLAI) is the most prominent bark protein. It is built up of four 32 kDa monomers which are post-translationally cleaved into a 15 kDa and a 17 kDa polypeptide. The second lectin (CLAII) is a minor protein, which strongly resembles CLAI except that its monomers are not cleaved into smaller polypeptides. Molecular cloning of the Cladrastis lectin family revealed also the occurrence of a lectin-related protein (CLLRP) which is the second most prominent bark protein. Although CLLRP shows sequence homology to the true lectins, it is devoid of carbohydrate binding activity. Molecular modelling of the three Cladrastis proteins has shown that their three-dimensional structure is strongly related to the three-dimensional models of other legume lectins and, in addition, revealed that the presumed carbohydrate binding site of CLLRP is disrupted by an insertion of three extra amino acids. Since it is demonstrated for the first time that a lectin and a non-carbohydrate binding lectin-related protein are the two most prominent proteins in the bark of a tree, the biological meaning of their simultaneous occurrence is discussed.

Amino Acid Sequence↗
PubMed1995

The bark of Robinia pseudoacacia contains a complex mixture of lectins. Characterization of the proteins and the cDNA clones.

Two lectins were isolated from the inner bark of Robinia pseudoacacia (black locust). The first (and major) lectin (called RPbAI) is composed of five isolectins that originate from the association of 31.5- and 29-kD polypeptides into tetramers. In contrast, the second (minor) lectin (called RPbAII) is a hometetramer composed of 26-kD subunits. The cDNA clones encoding the polypeptides of RPbAI and RPbAII were isolated and their sequences determined. Apparently all three polypeptides are translated from mRNAs of approximately 1.2 kb. Alignment of the deduced amino acid sequences of the different clones indicates that the 31.5- and 29-kD RPbAI polypeptides show approximately 80% sequence identity and are homologous to the previously reported legume seed lectins, whereas the 26-kD RPbAII polypeptide shows only 33% sequence identity to the previously described legume lectins. Modeling the 31.5-kD subunit of RPbAI predicts that its three-dimensional structure is strongly related to the three-dimensional models that have been determined thus far for a few legume lectins. Southern blot analysis of genomic DNA isolated from Robinia has revealed that the Robinia bark lectins are the result of the expression of a small family of lectin genes.

Amino Acid Sequence↗
PubMed1992

Modulation of arachidonic acid metabolism and cyclic AMP content of human alveolar macrophages.

The exposure of human alveolar macrophages to inflammatory mediators such as PAF (1 microM), fMLP (1 microM) or the calcium ionophore A23187 (1 microM) induced a rapid decrease in their intracellular concentration of cAMP. Inhibition of TXA2 synthesis by the specific thromboxane synthase inhibitor ridogrel (1-10 microM) or by non-specific inhibitors as indomethacin (1-10 microM), the cyclooxygenase inhibitor, or BW A4C (1-10 microM), the 5-lipoxygenase inhibitor, partially prevented the decrease in cAMP induced by the different inflammatory stimuli. Evidence for an indirect control of cAMP levels in human alveolar macrophages by inflammatory mediators through the production of arachidonic acid derivatives from the cyclooxygenase pathway is supported by this study.

Adult↗
PubMed1982

[Staged bronchial biopsies in the preoperative evaluation of primary bronchial cancer].

The systematic biopsying of the carina overlying a tumour, the main carina and of a contralateral carina was made a part of the work up in some patients with bronchial carcinoma, to assess operability. Different studies show that despite a normal macroscopic appearance these biopsies often reveal sub-mucous invasion. This microscopic extension might modify the resection planned, and even end in inoperability in the case of tracheal or contralateral tracheal invasion. We have studied the notes of 110 patients with primary bronchial carcinoma who have had systematic biopsies. All had a normal endoscopic appearance in the carinas biopsied and none revealed invasion by tumour. Of 110 patients, 37 had operations. In 1/3 (13/37) there was a discordance between the pre-operative bronchoscopic assessment and the local extension at thoracotomy, since 7 patients were subjected to a more extensive dissection than planned, 4 were exploratory thoracotomies only and in 4 the bronchial stumps were found to be invaded. Thus negative biopsies of healthy carinas overlying a tumour have proved to be false security and did not allow us to confirm the absence of tumour extension at peri-bronchial level in the local lymph nodes or in the mediastinum.

Adult↗
PubMedDate not supplied

[Plasma levels and membrane transports in red blood cell of tyrosine and tryptophane in depression. Evaluation at baseline and recovery].

The erythrocyte membrane transports (MT) of L-tyrosine and L-tryptophan, as well as their plasma levels, were measured in 143 depressed patients after a wash-out period of one week and before any antidepressant treatment, and then at regular intervals until they recovered. 49 normal subjects served as a control group. The perturbations of these biologic variables at baseline were different according to diagnostic groups (DSM III), compared to controls: significant decrease of the two MT in depressed bipolar disorders; significant decrease of MT in depressed bipolar disorders; significant decrease of MT tyrosine and significant increase of MT tryptophan in recurrent major depressions; no significant changes of MT in dysthymic disorders. The plasma levels of tyrosine and total tryptophan show a significant diminution in the 3 groups. The study of the evolution of these same variables after antidepressant treatment show a return to normal of the MT at recovery, as well as the plasma levels of tyrosine. The plasma levels of tryptophan stay low in depressed bipolar disorders and recurrent major depressions.

Adult↗
PubMedDate not supplied

[Frequency of chronic rhinitis in a population of young adults. Influence of pollen allergy and tobacco addiction (author's transl)].

A survey of 27 604 sujets aged mostly between 17 and 19 revealed that 33.5% of them had a regular nasal obstruction and that 13.6% repeated sneezing fits. Prevalence of nasal manifestations related to an allergy to graminaceae pollen was estimated at 5%. Besides there was a close relationship between the chronic nasal symptomatology and the smoking habits of the subjects concerned.

Adolescent↗