Purification of a PHA-like chitin-binding protein from Acacia farnesiana seeds: a time-dependent oligomerization protein.

A lectin-like protein from the seeds of Acacia farnesiana was isolated from the albumin fraction, characterized, and sequenced by tandem mass spectrometry. The albumin fraction was extracted with 0.5 M NaCl, and the lectin-like protein of A. farnesiana (AFAL) was purified by ion-exchange chromatography (Mono-Q) followed by chromatofocusing. AFAL agglutinated rabbit erythrocytes and did not agglutinate human ABO erythrocytes either native or treated with proteolytic enzymes. In sodium dodecyl sulfate gel electrophoresis under reducing and nonreducing conditions, AFAL separated into two bands with a subunit molecular mass of 35 and 50 kDa. The homogeneity of purified protein was confirmed by chromatofocusing with a pI = 4.0 +/- 0.5. Molecular exclusion chromatography confirmed time-dependent oligomerization in AFAL, in accordance with mass spectrometry analysis, which confers an alteration in AFAL affinity for chitin. The protein sequence was obtained by a liquid chromatography quadrupole time-of-flight experiment and showed that AFAL has 68% and 63% sequence similarity with lectins of Phaseolus vulgaris and Dolichos biflorus, respectively.

Rat alpha-fetoprotein heterogeneity. Comparative chemical study of the two electrophoretic variants and their Ricinus lectin-binding properties.

Two electrophoretic forms of rat alpha-fetoprotein were purified using immunosorbent chromatography and preparative electrophoresis on polyacrylamide gel slabs. Some of their respective chemical properties and their affinity for the Ricinus communis lectin (RCAI) were compared. Electrophoresis on polyacrylamide gradient gel in the presence of sodium dodecyl sulfate indicated a slight difference in molecular 74 000 for the slow alpha-fetoprotein (AFPA) and 72000 for the fat alpha-fetoprotein (AFPB). no significant difference in amino acid composition between AFPA and AFPB was found. A residue of valine was identified at the C-germinal end of both alpha-fetoproteins. The analysis of the CNRr-cleavage products reveals slight differences between AFPS and AFPB. The slow moving alpha-fetoprotein could be further fractionated on RCAI-sepharose column in two components, AFPA1 and AFPA2 differing by their sialic acid content.

Lectin of Pisum arvense seeds induces in-vivo and in-vitro neutrophil migration.

PAL is a glucose/mannose-specific lectin isolated from Pisum arvense seeds. Previously, we demonstrated the capacity of other leguminous lectins to induce oedema formation and neutrophil stimulation. To investigate the potential pro-inflammatory activity of PAL, we have studied its ability to induce neutrophil migration into peritoneal cavities of rats and neutrophil chemotaxis in-vitro. The role of resident cells and sugar residues on PAL activity was analysed. PAL or saline (control) were administered intraperitoneally to rats, and total and differential leucocyte (macrophages, neutrophils and mast cells) counts were performed. The role of resident cells on the PAL effect was evaluated using three strategies: reducing the total resident cell population by lavage of rat cavities with saline; increasing macrophage population by treating animals with thioglycolate; and depleting mast cell population by subchronic treatment of rats with compound 48/80. PAL induced in-vitro and in-vivo neutrophil migration. In-vivo, PAL (50, 100, 200 and 300 microg) significantly (P < 0.05) and dose-dependently increased neutrophil migration by 600, 740, 900 and 940%, respectively, showing maximal effect 4 h after injection. PAL induced mononuclear cell migration. The neutrophil stimulatory effect of PAL was potentiated in animals treated with both thioglycolate and compound 48/ 80. The indirect lectin chemotactic effect was shown in rats injected with supernatant from cultured macrophages stimulated by PAL. In conclusion, PAL was shown to exhibit in-vivo and in-vitro proinflammatory activity. The in-vivo effect seemed to occur by a dual mechanism that was independent, but also dependent, on resident cells.

Purification and partial characterization of two lectins from the cactus Machaerocereus eruca.

Two lectins (MEAI and MEAII) were isolated from the cactus Machaerocereus eruca by affinity chromatography on mucin-Sepharose and partially characterized with respect to their biochemical and carbohydrate binding properties. Both are oligomeric glycoproteins consisting of 35 kDa monomers. Amino acid analysis indicates that both lectins have similar composition with high amounts of glycine, glutamic acid and serine. MEAI and MEAII contain approximately 36 and 24% (w/w) of carbohydrates, respectively. They agglutinate erythrocytes from several animal species. Binding specificity was directed to galactose-containing oligosaccharides and glycopeptides. The M. eruca lectins are the first lectins to be isolated from a species belonging to the plant family of Cactaceae.

Lectin-resistant variants of mouse Lewis lung carcinoma cells. II. Altered glycosylation of membrane glycoproteins.

Lectin-resistant variants of mouse Lewis lung carcinoma LL2 cell line, selected with wheat germ agglutinin (WGAR), Ricinus communis agglutinin II (RCA IIR) and Aleuria aurantia agglutinin (AAAR) were studied. Total cellular glycopeptides of the parent LL2 line and of the five lectin-resistant variants were analyzed by gel filtration and affinity chromatography on immobilized concanavalin A and Lens culinaris agglutinin. The results revealed that low-metastatic WGAR and RCA IIR variants possessed less highly branched tri- and tetra-antennary N-acetyllactosaminic type glycans with a simultaneous increase in biantennary N-acetyllactosaminic type, oligomannosidic type or hybrid type glycans, as compared to the parent metastasizing LL2 cell line. These findings imply that cell surface carbohydrate changes may possibly be relevant for metastasis. However, the AAAR variant, which possessed reduced spontaneous metastatic ability after s.c. administration, but increased experimental metastatic ability after i.v. inoculation, exhibited apparently the same glycan pattern than the parent LL2 line. This particular variant is under investigation in order to find specific modification(s) of glycan(s) which could play a specific role in the metastatic process.

Altered glycosylation in Madin-Darby canine kidney (MDCK) cells after transformation by murine sarcoma virus.

The changes in glycosylation of an immortalized epithelial cell line (MDCK) before and after progression towards a more malignant phenotype have been studied. The parental MDCK-3 cells were immortalized after long-term passage in vitro and have shown no tendency for spontaneous acquisition of malignancy-related phenotypes such as tumorigenicity, invasion and metastasis. They conserved morphological and functional characteristics of the epithelial tissue of origin. The ras-MDCK cells acquired the fully malignant phenotype after transformation with a Harvey murine sarcoma virus; they were immortalized, invasive in vitro and produced invasive and also metastatic tumors after subcutaneous injection into nude mice. Using immobilized lectins and gel chromatography, before and after liberation of O-linked glycans from the peptide moieties and also after removal of terminal sialic acid, we have found differences in the glycosylpeptides of both whole cells and cell surface trypsinates from ras-MDCK cultures as compared to the parental MDCK-3 cultures: (i) more sialic acid in the N-linked tri- and tetra-antennary structures; (ii) more fucosylation in the N-glycosylpeptides; (iii) more bi-antennary N-glycosylpeptides and less O-linked glycans; and (iv) a lower molecular weight of the O-linked glycans probably due to a decreased sialylation. It is concluded that alterations in sialylation and fucosylation of the cell surface exposed glycans accompanied progression of MDCK-3 cells towards a more malignant phenotype.

Lectin-resistant variants of mouse Lewis lung carcinoma cells. I. Selection and in vivo properties.

The availability of lectin-resistant cell lines with altered carbohydrate moieties in cell surface glycoproteins and glycolipids has greatly facilitated study of the involvement of cellular glycoconjugates in tumor growth and metastasis. We present here a new animal model for metastasis study based on mouse Lewis lung carcinoma LL2 in vitro cell line. From this line, five lectin-resistant variant sublines were selected with the following lectins: wheat germ agglutinin (WGAR), Ricinus communis agglutinin II (RCA IIR) and Aleuria aurantia agglutinin (AAAR). The correlation of the lectin resistance with their in vitro and in vivo growth properties, and especially lung colonizing ability, were investigated. Three WGAR variants with well-preserved tumorigenicity revealed reduced metastatic ability, both spontaneous, after subcutaneous (s.c.) administration and experimental, after intravenous (i.v.) administration. The RCA IIR variant also possessed reduced spontaneous and experimental metastatic ability, but exhibited higher growth rate of local s.c. tumors. The AAAR variant possessed reduced spontaneous metastatic ability but its ability to colonize the lungs after i.v. administration was five-fold higher than that of the parent LL2 line, whereas its tumorigenicity remained unchanged. The relative differences among WGAR variants and parent LL2 line, concerning their experimental metastatic ability, remained similar in cyclophosphamide-modified mice to those in normal recipients.

Isolation and characterization of surface glycopeptides from adult rat hepatocytes in an established line.

The fractionation of glycopeptides isolated from the surface of an established line of adult rat hepatocytes, after 48 h metabolic labeling with [14C] glucose leads to the demonstration of the presence of two types of glycopeptides: i) O-glycopeptides containing N-acetylneuraminic acid, galactose and N-acetylgalactosamine, ii) N-glycopeptides with mannose, galactose, N-acetylgluosamine, fucose and N-acetylneuraminic acid. The former yield, by alkaline reductive degradation, a trisaccharide: sialyl-galactosyl-N-acetyl-galactosaminitol, a tetrasaccharide : di-sialyl-galactosyl-N-acetyl-galactosaminitol and a small amount of the disaccharide: galactosyl-N-acetyl-galactosaminitol. The latter are alkali-stable and can be divided by ion-exchange chromatography on DEAE-cellulose into i) acidic glycopeptides, not retained on a Concanavalin A-Sepharose column and belonging to the N-acetyllactosaminic type glycopedtides and ii) neutral glycopeptides which can be further fractionated on the Con-A-Sepharose column into non-retained glycopeptides belonging to the N-acetyllactosaminic type, and glycopeptides retained on the Sepharose-Con A column, containing only N-acetylglucosamine and mannose residues and related to the oligomannosidic type glycopeptides.

Separation of two different populations of granulocytes of Nereis diversicolor (Annelida) by selective agglutination with lectins.

Methods for obtaining coelomocyte populations from Nereis diversicolor by selective agglutination have been developed. Two main types of granulocytes have been successfully separated and recovered using respectively galactose and fucose specific lectins. 85 to 90% of the separated cells were viable.

Distribution and nature of membrane receptors for different plant lectins in the coelomocyte subpopulations of the Annelida Nereis diversicolor.

Studies on membrane receptors have been performed on the Nereis coelomocytes using various lectins. In the agglutination assay, only LCA and WGA appeared nonreactive. Fluorescent lectins showed the poor reactivity of the eleocytes and the diversity of the receptors according to the granulocyte types. Types I-granulocytes reacted only with Con A. Type II-granulocyte membrane contained mannose and galactose receptors (reactivity with Con A, PNA and SBA). The type III-granulocyte membrane revealed the presence of mannose and fucose receptors (UEA, AAA). Electron microscope investigations with HRP-DAB or mannosyl labelled Con A, RCAI and LTA have confirmed the distribution of the membrane receptors.

Mitogenic stimulation of mouse lymphoid cells by Aleuria aurantia agglutinin.

An investigation was undertaken to determine if an agglutinin isolated from Aleuria aurantia possesses a mitogenic activity. Proliferation response of mouse lymphoid cell cultures was measured by 3H-thymidine uptake. The results revealed that Aleuria aurantia agglutinin at the concentration of 1 microgram/ml is mitogenic for Thy-1+ splenocytes and cortisone-resistant thymocytes.

Aleuria aurantia agglutinin. A new isolation procedure and further study of its specificity towards various glycopeptides and oligosaccharides.

A new procedure for isolating a L-fucose-specific lectin from the mushroom Aleuria aurantia is described. The fine specificity of the purified lectin was determined by inhibition of agglutination of human red blood cells by various glycopeptides and oligosaccharides, and by studying the affinity of the immobilized lectin towards glycopeptides and oligosaccharides. Results of inhibition of hemagglutination showed that the lectin presents the highest affinity towards alpha-(1----6)-linked L-fucosyl groups. Immobilized Aleuria aurantia agglutinin interacts strongly with all N-glycosylpeptides or related glycans possessing an alpha-L-fucopyranosyl group linked to O-6 of the 2-acetamido-2-deoxy-beta-D-glucopyranosyl residue involved in the glycosylamine linkage. In addition, presence of alpha-(1----3)-linked L-fucosyl groups greatly enhances the affinity of the lectin for the alpha-(1----6)-L-fucosylated glycans. The immobilized Aleuria lectin is a powerful tool for the resolution of the microheterogeneity of L-fucosylated glycopeptides and glycans of the N-acetyl-lactosamine type.

Affinity of four immobilized Erythrina lectins toward various N-linked glycopeptides and related oligosaccharides.

The behavior of N-acetyllactosamine-type oligosaccharides and glycopeptides on columns of four different Erythrina agglutinins immobilized on Sepharose was examined. The sugar-binding specificity of the four lectins is very similar and is directed toward unmasked N-acetyllactosamine sequences, the main difference between the four lectins being the relative strength of interaction of the lectins with a given glycan. Substitution of the N-acetyllactosamine sequences by sialic acid residues, either at O-3 or O-6 of galactose completely abolishes the affinity of the lectins for the saccharides. The presence of one or several alpha-Fuc-(1----3)-GlcNAc groups decreases or completely inhibits the interaction between the glycopeptides and the Erythrina lectins. Substitution of the beta-mannose residue by an additional bisecting beta-(1----4)-N-acetylglucosamine residue decreases the affinity of the lectins for these structures as compared to the unsubstituted ones. Surprisingly, the affinity of the lectins for the oligosaccharides tested is higher than for the corresponding glycopeptides. Our findings show that, after careful calibration with well-defined oligosaccharides and glycopeptides, the immobilized Erythrina agglutinin-Sepharose columns provide valuable tools for the fractionation of N-acetyllactosamine-containing oligosaccharides and glycopeptides.

Structural analysis of the carbohydrate chains isolated from mistletoe (Viscum album) lectin I.

Two glycopeptide fractions prepared from mistletoe (Viscum album) lectin I by Pronase digestion were fractioned by affinity chromatography on a concanavalin A-Sepharose column. With 400-MHz 1H NMR spectroscopy, in conjunction with sugar analysis, the following oligosaccharide structures could be determined: two oligomannose-type glycans in the ratio 4:1, one containing six mannose and the other containing five mannose units, both with two 2-acetamido-2-deoxyglucose units. In addition, a mannotriosyl-->N,N'-diacetylchitobiose glycan containing a xylosyl group and an alpha-fucosyl group (1-->3)-linked to the 2-acetamido-2-deoxyglycosyl-1 residue, a common core element of many plant glycoproteins, was also observed.

Isolation of isolectins from Vitis vinifera L. Cv. Chardonnay grape berries.

A lectin fraction from Chardonnay grape juice has been isolated by affinity chromatography on a column of p-aminophenyl beta-D-glucoside-derivatized agarose. The lectin fractions agglutinate rabbit and human erythrocytes without serological specificity. None of the usual monosaccharides, glycosides, or glycoproteins inhibit the hemagglutinating activity. Erythroagglutination is only inhibited by nitrophenyl glycosides, p-nitrophenyl beta-D-glucoside being the strongest inhibitor. In SDS-PAGE in the presence of 2-mercaptoethanol and gel filtration HPLC, the lectin fraction gave a single band or peak corresponding to M(r) 13.2-11.9 kDa, thus indicating it to be a monomer. Three bands were observed by isoelectric focusing with pI values of 4.1, 4. 4, and 4.9. The isolectins seem to be glycoproteins since they are bound on a concanavalin A-Sepharose column.

[The plasma membrane glycoconjugates of normal and transformed cells (author's transl)]. / Les glycoconjugués de la membrane de surface des cellules normales et cancéreuses.

After having reviewed the importance of glycoconjugates in the organisation of the cell membrane and the multiple roles played by these membrane constituants, the disorders characteristics of malignant transformation are described : First, the changes affecting cellular properties (diminution of cellular adhesivity, abolition of the control of cell growth, disturbance of membrane permeability...) and second, the modifications concerning the glycoconjugates of the cell surface in the course of malignant transformation : alterations affecting membrane glycolipids and glycoproteins. It appears that certain modifications of glycannic structures of membrane glycoproteins, for whatever cell type and transforming agent, seem at the moment to constitute the only abnormality permanently associated with the tumorigenicity of malignant cells.

[Systematized papulosis of the lower scapular areas with ultrastructural anhist bodies: specific cutaneous symptoms of Hunter's disease (author's transl)]. / Papulose sous-scapulaire systématisée avec corps anhistes en microscopie électronique: signes cutanés spécifiques de la maladie de hunter.

Papulosis of the scapular areas is a characteristic dermatologic sign of Hunter's disease. It has not been described in the other mucopolysaccharidoses. This sign had been detailed by Hunter in 1917 in his princeps observation. We noted it in two cases of the disease. The ultrastructural study showed an accumulation in the connective interstitial substance of anhist bodies of intra-cellular origin.

[Menkes' disease (new skin and hair ultrastructural abnormalities) (author's transl)]. / Maladie de menkes anomalies ultrastructurales cutanéophanériennes nouvelles.

The authors report the sixth case of Menkes' kinky hair disease. This boy has been observed for as long as 16 months, and he his still alive at the time of publication. This genetic, X linked disorder of copper metabolism is always fatal in childhood. Diagnosis is evoked when is noted the conjunction of progressive cerebral degeneration, seizures, with pili torti and monilethrix. It can be asserted with the very low copper and cerulo-plasmin blood levels. Recognition of the disease in utero might be possible. New findings in skin' electron microscopy and hair' scanning electron microscopy are reported here. And two RX scanner of the brain have been performed.