Purification and characterization of an anti-(A+B) specific lectin from the mushroom Hygrophorus hypothejus.

A lectin (HHL) was isolated from the fruiting body of the mushroom Hygrophorus hypothejus by a combination of affinity chromatography on stromas of group B erythrocytes embedded in polyacrylamide gel, and DEAE-trisacryl and gel filtration chromatography. Its molecular mass, as determined by gel filtration, is estimated to be 68000 kDa and its structure is tetrameric with four identical subunits assembled with non-covalent bonds. HHL agglutinates specifically A and B blood group erythrocytes and in hemagglutination inhibition assays, exhibits sugar-binding specificity toward lactose, the anomeric alpha form being more effective than the beta form.

Characterization of a Lectin from Lactarius deterrimus (Research on the Possible Involvement of the Fungal Lectin in Recognition between Mushroom and Spruce during the Early Stages of Mycorrhizae Formation).

A lectin (LDetL) was isolated from carpophores of the mushroom Lactarius deterrimus, a specific symbiont of the spruce, by a combination of affinity, hydroxylapatite, and gel-filtration chromatography. Its molecular mass, as determined by gel filtration, is about 37,000 D, and its structure is dimeric, with two identical subunits assembled by noncovalent bonds. It appeared homogeneous on high-performance liquid chromatography gel filtration, but isoelectric focusing revealed microheterogeneity, with a main band in the pH zone near 6.5. Amino acid analysis showed that LDetL contains a large proportion of glycine and especially methionine. Hapten inhibition assay indicated that LDetL is most specific for [beta]-D-galactosyl(1->3)-D-N-acetyl galactosamine residues. The lectin was formed in the in vitro-cultivated mycelium, and anti-lectin antibodies revealed by indirect immunofluorescence the presence of lectin in the cell wall. Receptor sites for LDetL were found on the roots, especially on the root hairs, of axenically grown spruce seedlings. The lectin LDL previously isolated by us from the taxonomically related mushroom Lactarius deliciosus, a symbiont of the pine, does not bind to the spruce radicle. This suggests a role of the fungal lectin in recognition and specificity during the early stages of mycorrhizae formation.

Use of yeasts in affinity chromatography.

The use of the yeast Candida lipolytica as a support in affinity chromatography for the purification of lectins of Ricinus communis seeds has been studied. A comparison was made with columns of erythrocyte stromas and Sepharose 4B with respect to protein yields, the agglutinating activity yield, and the electrophoretic characteristics of the eluted substances. Even though the yield is less than with other supports, it does appear that the yeast columns represent an effective method for the purification of ricin lectins.

Isolation and characterization of a lectin from the mushroom, Lactarius deliciosus.

A lectin (LDL) has been isolated from carpophores of the edible mushroom, Lactarius deliciosus, using a combination of affinity chromatography on stromas of group O erythrocytes embedded in polyacrylamide gel and hydroxylapatite, and gel filtration chromatography. Its molecular weight, as determined by gel filtration, is about 37,000 and its structure is dimeric, with two distinct types of subunits (about 19,000 and 18,000). It appeared homogeneous on HPLC gel filtration, but exhibited microheterogeneity on isoelectric focusing. Amino acid analysis revealed that it contains a large amount of glycine. Hapten inhibition assaying indicated that the Lactarius lectin is most specific for D-Gal beta 1----3D-GalNAc. The lectin was found in the mycelium and its possible role in the fungus is discussed.

Isolation and characterization of an N-acetyllactosamine-binding lectin from the mushroom Laetiporus sulfureus.

A hemagglutinating and hemolytic lectin (PSL) has been isolated from carpophores of the parasitic mushroom Laetiporus sulfureus by affinity chromatography on Sepharose. Its molecular weight, as determined both by gel filtration and by electrophoresis in non-denaturing conditions, is about 190,000 and its structure is tetrameric, with two distinct types of subunits (about 60,000 and 36,000). It appeared homogeneous on HPLC gel filtration but exhibited microheterogeneity on isoelectric focusing. Hapten inhibition assay indicated that the Laetiporus lectin is specific for N-acetyllactosamine residues and that hemagglutinating and hemolysis activities are supported by the same site.

Use of lectins for a comparative study of cell wall composition of different anaerobic rumen fungal strains.

The technique based on fluorescein-linked lectins used to determine the cell wall structure of anaerobic rumen fungi belonging to genera: Neocallimastix, Piromonas and Sphaeromonas, appears to be an interesting tool for distinguishing between strains. Furthermore this technique shows differences of cell wall composition between different parts of the thallus (spores, sporangia, rhizoïds).

Identification and taxonomy of human and animal leishmanias by lectin-mediated agglutination.

The surface polysaccharides of two strains of lizard leishmanias, of the guinea pig parasite L. enrietti and of nine strains of human leishmanias belonging to the groups mexicana, donovani and tropica were studied by lectin-mediated agglutination. Twenty-three lectins prepared from seeds or from higher fungi carpophores were used. They revealed the presence of L-fucose, N-N'-diacetylchitobiose, alpha-D-glucose, alpha-D-mannose, beta-D-galactose, N-acetyl-D-galactosamine and lactose. We noted a range in the number and variety of lectin receptor sites detectable on the surface of the leishmanias, with the reptiles strains having the fewest sites and the tropica group having the most sites. We were unable to find specific group lectins, but it seems possible to identify a strain within each group by a lectin-binding pattern.

Potential anti-inflammatory effects of Melaleuca alternifolia essential oil on human peripheral blood leukocytes.

The fungicidal and bactericidal actions of the essential oil (EO) of Melaleuca alternifolia seem well established, but their anti-inflammatory and antioxidative effects remain unclear. This study investigated in vitro the possible role of whole Melaleuca alternifolia EO as a modulator of the inflammatory/non-specific immune response by exploring the chemotaxis and kinetic radical oxygen species (ROS) production of leukocytes and cytokine secretion in peripheral blood mononuclear cells (PBMCs) in humans. The influence of Melaleuca alternifolia EO on the chemotaxis under agarose of isolated neutrophils (PMNs) was evaluated. The kinetics of ROS production by stimulated total circulating leukocytes was followed over 2 h by recording the fluorescence intensity of oxidized dihydrorhodamine 123. The effects of this EO on pro-(interleukin IL-2) and anti-(IL-4 and IL10) inflammatory cytokine secretions were determined by ELISA following incubation of PBMCs with the EO for 24 h. Melaleuca alternifolia EO was inefficient on the chemotaxis of PMNs. It exerted an antioxidant effect, reducing ROS production throughout the kinetic study. Melaleuca alternifolia EO inhibited PBMC proliferation, as revealed by a reduction in IL-2 secretion by stimulated lymphocytes. This EO at 0.1% directly increased the secretion of the anti-inflammatory cytokine IL-4 compared with IL-4 secretion without EO (18.5 +/- 10.0 vs 3.3 +/- 1, p < 0.05), and also increased IL-10 secretion at 0.01% (94.9 +/- 38.7 vs 44.1 +/- 18, ns). Melaleuca alternifolia EO may not only act as an anti-inflammatory mediator through its antioxidant activity but may also efficiently protect the organism by reducing the proliferation of inflammatory cells without affecting their capacity to secrete anti-inflammatory cytokines.

Leptin: a proliferative factor for breast cancer? Study on human ductal carcinoma.

Mammary adipose tissue is an important source of paracrine mitogens and anti-mitogens, including insulin-like growth factor, transforming growth factors, and cytokines (especially, TNFalpha and IL-1beta). Nevertheless, it is also an important source of the adipocytokine, leptin. Recently, leptin was reported to stimulate the proliferation of various cell types (pancreatic beta cells, prostate, colorectal, lung, etc.) as a new growth factor. It was also shown to stimulate the proliferation of breast cancer cell lines. In this study, we conducted an immunohistochemical analysis of leptin expression in normal tissue and benign and malignant ductal breast cell, representing the different states of the invasion process. We determined for the first time that leptin is expressed both by ductal breast tumors and by benign lesions as atypical hyperplasia. This suggests that leptin may be taken up or synthesized by all modified ductal breast cells, and may prove a proliferative factor. Moreover, leptin is unexpressed by normal tissue in the healthy breast but is exhibited by the normal tissue in near vicinity of the malignant ductal breast lesions. We also postulated that leptin may be a prognostic or diagnostic factor for ductal breast cancer. These putative hypotheses require further study.

[Study using lectins of the parietal polysaccharides of Sphaeromonas communis]. / Etude à l'aide de lectines des polysaccharides pariétaux de Sphaeromonas communis.

Using fluorescein isothiocyanate-labeled lectins of various specificities, differences in the cell wall polysaccharide composition among the different parts of the thallus and during the cycle of S communis were demonstrated.

[Fixation of various lectins at the surface of Crithidia luciliae]. / Etude de la fixation de diverses lectines à la surface de Crithidia luciliae

Suspensions of Crithidia luciliae have been treated with 30 lectins: protozoans are agglutinated only by lectins inhibited with oses of structures I an II according to Mäkelä, and by lectins the site of fixation of which are unknown. The use of 5 lectins conjugated to fluorescein corroborate that lectins in congruity with group I and II, contrarily to those of group III, fasten upon the membrane and the flagella of Crithidia luciliae.