Gangliosides

Breast cancer cells can invade and generate metastasis via either lymphatic or blood vessels. Sialyl Lewis X (SLeX) and Sialyl Lewis a (SLea) are carbohydrate molecules that mediate the adhesion between tumor cells and the endothelium. These antigens are not expressed on normal breast tissue. Overexpression of SLeX and SLea is combined with poor prognosis and malignant relapse. E-cadherin mediates tumor cell-tumor cell adhesion. Partial or complete loss of E-cadherin expression has also been found to correlate with poor prognosis in breast cancer patients. Another factor involved in metastasis is Cathepsin-D, a lysosomalprotease. Cathepsin-D plays a role in cell proliferation and inhibition of tumor cell adhesion. In this study, we analysed the combined expression of SLeX, SLea, Cathepsin-D and E-cadherin in breast carcinoma in situ, invasive carcinomas without metastasis and invasive carcinomas with lymph node metastasis. Slides of paraffin-embedded tissue of carcinoma in situ (8 D...

Myelin-associated glycoprotein (MAG) is expressed on the innermost myelin membrane wrap, directly apposed to the axon surface. While it is not required for myelination, MAG enhances long-term axon-myelin stability, helps to structure nodes of Ranvier, and regulates the axon cytoskeleton. In addition to its role in axon-myelin stabilization, MAG inhibits axon regeneration after injury; MAG and a discrete set of other molecules on residual myelin membranes at injury sites actively signal axons to halt elongation. Both the stabilizing and axon outgrowth inhibitory effects of MAG are mediated by complementary MAG receptors on the axon surface. Two MAG receptor families have been described, sialoglycans (specifically gangliosides GD1a and GT1b) and Nogo receptors (NgR’s). Controversies remain about which receptor(s) mediate which of MAG’s biological effects. Here we the findings and challenges in associating MAG’s biological effects with specific receptors.

High titers of anti-GD,, antibodies have been found in patients with Guillain-Bar& syndrome or motor neuropathy. To determine the possible diagnostic relevance of these antibodies, we measured serum anti-GD,, IgG and IgM antibodies by enzyme-linked immunosorbent assay in 195 patients with different motor syndromes and in 335 control subjects. Moderately high antibody titers (I/ 1,280-1/5,120) were occasionally found in patients with chronic inflammatory demyelinating polyneuropathy (5%), multifocal motor neuropathy (18%), lower motor neuron disease (3.8%), or amyotrophic lateral sclerosis (1.8%) and in immunological control subjects (1.2%), while titers of 1/20,480 or higher were only found in 2 patients with Guillain-Barri! syndrome (IgG in both) and 2 with motor neuropathy and IgMX monoclonal gammopathy improving with immunotherapy. In both motor neuropathy patients and the Guillain-Bar& syndrome patient who were retested during recovery, anti-GD,, titers decreased concomitantly with clinical improvement. High anti-GD,, antibody titers may be found in several motor syndromes but only markedly increased anti-GD,, titers are strictly associated with potentially treatable dysimmune neuropathies. Carpo M, Nobile-Orazio E, Meucci N, Camba M, Barbieri S, Allaria S, Scarlato G. Anti-GD,, ganglioside antibodies in peripheral motor syndromes. Ann Neurol 1996;33:539-543 High titers of serum antibodies to the ganglioside GD,, were demonstrated recently in some patients with Guillain-Bark syndrome (GBS) [l-51 and in a patient with motor neuropathy (MN) associated with IgM monoclonal gammopathy [6], whereas lower antibody levels were detected in patients with motor neuron disease (MND) [7, 81. The anti-GD,, antibodies were mostly IgG in patients with GBS and IgM in those with MN or M N D and the titers, at least in GBS patients [l, 21, decreased concomitantly with clinical improve-From the

Introduction: Dr. C. Miller Fisher described the appearance of unilateral facial palsy after resolution of ataxia in a patient with the eponymic Miller Fisher syndrome (MFS). However, there have been very few reports of delayed appearance of facial weakness in Guillain-Barré syndrome (GBS) and MFS when the other neurological signs reached nadir or started improving. Methods: In this study we reviewed the clinical and laboratory findings of consecutive patients with GBS (n = 195) and MFS (n = 68). Results: Delayed facial weakness occurred in 12 (6%) GBS and 4 (6%) MFS patients and was unilateral in 5 (42%) GBS and 2 (50%) MFS patients. In those patients with delayed facial weakness, neither limb weakness nor ataxia progressed, and facial weakness disappeared without immunotherapy. Conclusions: Because facial weakness can lead to further morbidity, it would be prudent for clinicians to warn patients of this possibility, although additional immunotherapy is usually not required. Muscle...

Targeting glycosphingolipid synthesis has emerged as a novel approach for treating metabolic diseases. 32 (EXEL-0346) represents a new class of glucosylceramide synthase (GCS) inhibitors. This report details the elaboration of hit 8 with the goal of achieving and maintaining maximum GCS inhibition in vivo. 32 inhibited GCS with an IC 50 of 2 nM and achieved maximum hepatic GCS inhibition after four or five daily doses in rodents. Robust improvements in glucose tolerance in DIO mice and ZDF rats were observed after 2 weeks of q.d. dosing. Four weeks of dosing resulted in decreased plasma triglycerides and reduced hepatic fat deposition. Thus, 32 provides insight into the amount of metabolic regulation that can be restored following achievement of maximal target knockdown.

The effect of gangliosides extracted from human group O Rh + erythrocytes on haemagglutination by BK virus was investigated. Experiments were performed on both ganglioside mixtures and isolated fractions separated by column chromatography and characterized by thin-layer chromatography. These results were compared with those obtained with standard preparations of gangliosides, and the inhibiting activity was shown to be confined mainly to gangliosides with a RF lower than GM1. It was also observed that the insertion of gangliosides in liposomes increased the haemagglutination-inhibiting activity and that ganglioside coating restored the ability of glycosidasetreated human red blood cells to agglutinate.

Ganglioside function in eukaryotic cells encompasses a variety of modulatory interactions related to both development and mature cellular behavior. In relation to the nervous system this includes induction of neurite outgrowth and trophic/neuroprotective phenomena; more generally this applies to ganglioside effects on receptor function, adhesion reactions, and signal transduction mechanisms in neural and extraneural systems. Underlying many of these trophic effects are ganglioside-induced changes in cellular calcium, accomplished through modulation of Ca2+ influx channels, Ca2+ exchange proteins, and various Ca2+-dependent enzymes that are altered through association with gangliosides. A clear distinction needs to be drawn between intrinsic functions of gangliosides as naturally expressed by the cell and activities created by application of exogenous ganglioside(s) that may or may not reflect natural function. This review attempts to summarize findings in this area and point to poss...

Background: Some patients with Fisher syndrome (FS) developed subsequent descending tetraparesis (Fisher/ Guillain-Barré overlapping syndrome: FS/GBS). The assumption is that such descending progression may frequently lead to respiratory failure. Objective: To investigate whether patients with FS/GBS more often require artificial ventilation than those with typical GBS and which clinical and serological findings are useful predictors. Methods: Medical records were reviewed of patients who had acute ophthalmoplegia, ataxia and areflexia, as well as subsequent tetraparesis with monophasic course. Forty-five patients fulfilled the FS/GBS criteria. Clinical and serological features were analysed, and clinical predictors of mechanical ventilation were investigated. Results: FS/GBS patients more frequently required mechanical ventilation than did GBS patients (24% vs 10%, p = 0.04). The former also needed artificial ventilation earlier than the latter (p = 0.03), but none of the FS patients required it. As the initial symptom, ventilated FS/GBS patients more frequently showed titubation than non-ventilated patients (55% vs 18%, p = 0.04). During the course of the illness, descending tetraparesis was more common in 11 ventilated FS/GBS patients than in the other 34 non-ventilated patients (64% vs 21%, p = 0.02). The need for artificial ventilation was not associated with anti-GQ1b IgG antibodies, monospecific anti-GT1a IgG antibodies or IgG antibodies to various ganglioside complexes. Conclusions: FS/GBS patients significantly needed mechanical ventilation more often. Such patients showing titubation and descending tetraparesis need to be carefully monitored as the illness progresses because those clinical features are helpful predictors of respiratory failure.

Miller Fisher syndrome is characterized by a triad of ataxia, ophthalmoplegia, and reduced or absent tendon reflexes, with minimal if any limb weakness. Anti-GQ1b immunoglobulin G antibodies are present in high titers in most patients. Presented is a two-year-old female with Miller Fisher syndrome whose blood serum was negative for anti-GQ1b immunoglobulin G antibodies.

This work reviews the current state-of-the-art of liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) techniques applied to the analysis of pesticides in fruit-based and vegetablebased matrices. Nowadays, simultaneous trace analysis of hundreds of pesticides from different classes is required, preferably in just one run. The most commonly used QqQ-MS technology presents certain limitations in its application in a cost and effective way when analyzing a large number of pesticides. Thus, this review includes HRMS technology as a reliable complementary alternative allowing the analysis of a wide range of pesticides in food. Its capabilities and limitations in identifying, confirming and quantifying pesticides are discussed. HRMS instruments can adequately address such issues; however, the main drawbacks are as a result of insufficient prior optimization of the operational parameters during nontarget analysis in full-scan mode and due to software shortcomings.

The use of CNS cultures for detection and quantification of neuronotrophic activity in the CNS has been analyzed. In particular the development, i.e., neurotransmitter uptake characteristics, and survival of dopaminergic and GABAergic neurons in fetal mouse (E13)-dissociated mesencephalic cells cultured in serum-free, hormone-supplemented medium have been assessed as a function of culture time and cell density. At all times, more than 98% of the cells were classified as neurons on the basis of immunocytochemical criteria. Results indicate that the increase of cell density in vitro significantly enhances specific high-affinity dopamine uptake per dopaminergic cell and cell survival. This effect is not limited to the dopaminergic cells and suggests that the development of neurotransmitter-related traits and cell survival are influenced by cell density-derived trophic signals. The above-mentioned cultures and parameters have also been used to detect neuronotrophic activity in adult mam...

Background: Most studies of Campylobacter infection triggering Guillain-Barré Syndrome (GBS) are conducted in western nations were Campylobacter infection and immunity is relatively rare. In this study, we explored Campylobacter infections, Campylobacter serotypes, autoantibodies to gangliosides, and GBS in Egypt, a country where Campylobacter exposure is common.

The structural-reporter-group resonances in the 'H-n.m.r. spectra of a series of ganglioside-derived oligosaccharides are completely assigned. The three different types of sialic acid residues which may occur in these compounds could be adequately characterized. They are distinguishable on the basis of the set of ..chemical shifts of their H-3a and H-3e atoms. The mutual influence of GalNAc #I-(1+4) and NeuSAc (y-(2+3), both linked to the same Gal residue, on the 'H-n.m.r. parameters of each other, reflects a well-defined solution conformation, which is held to be responsible for the resistance of this "internal" sialic acid towards various sialidases.

IgG anti-ganglioside antibodies were found in two patients with motor neuropathy. The first patient had a chronic axonal neuropathy with persistently elevated anti-GMl antibodies. The second patient had an acute axonal neuropathy with anti-GMl, Gt)to and asialoGM~ antibodies. In both, the IgG subclass study showed that the antibodies belonged to the IgG1 subclass. An enzyme-linked immunosorbent assay (ELISA) for light chains revealed anti-ganglioside antibodies of the lambda type.

In this study, the antihypertensive activity in spontaneously hypertensive rats of two peptides isolated from b-lactoglobulin hydrolysates with thermolysin was evaluated. These peptides, with sequences LLF [b-lg f(103-105)] and LQKW [b-lg f(58-61)], showed potent in vitro ACE-inhibitory activity. Two hours after administration, both sequences caused a clear and significant decrease in the blood pressure of these rats. The impact of a simulated gastrointestinal digestion on ACEinhibitory and antihypertensive activities of these peptides was also studied. The results showed that both fragments were susceptible to proteolytic degradation after incubation with pepsin and Corolase PP Õ . In addition, their in vitro ACE-inhibitory activity decreased after the simulated digestion. It is likely that fragment LQK was the active end product of the gastrointestinal digestion of peptide LQKW. The fragment LL, observed after digestion of peptide LLF, probably exert its antihypertensive effect through a mechanism of action different than ACE-inhibition.

IgM antibodies against gangliosides and their complexes were studied in sera from 54 patients with polyneuropathy and IgM monoclonal gammopathy (IgM-PNP) without anti-MAG antibodies. Anti-ganglioside antibodies were found in 19 (35%) patients. Five (9%) patients had antibodies against ganglioside complexes. IgM antibodies against gangliosides activated complement in vitro. Light chain usage was restricted to kappa or lambda in most, but not all patients.

Motor neuropathy with multifocal conduction blocks represents a recently identified autoimmune disorder of the peripheral nerve myelin. Association of motor neuropathies or neuronopathies with thyroid disorders, such as hyperthyroidism, hypothyroidism or thyroid neoplasms has been rarely described. We studied a 61-year-old man with a 2-year-history of slowly progressive weakness of the left limbs with atrophy and fasciculations. Nerve conduction velocity studies revealed multifocal motor conduction blocks. Serum IgM titer of antibodies against GM1 was elevated (1:1280; n.v. up to 1:640). Thyroid studies were compatible with Hashimoto's thyroiditis. Therapy with high dose intravenous immunoglobulins was followed by a prompt clinical recovery. Then the disease assumed an intravenous immunoglobulins dependent course with a full clinical, but transient, recovery. This is the first observation of an association of multifocal motor neuropathy with high titers of GM1 and Hashimoto's thyroiditis and reinforces the multifocal motor neuropathy autoimmune origin as well as the repeated clinical recoveries after intravenous immunoglobulins. This case also suggests to deeply investigate the thyroid function in patients with multifocal motor neuropathy. q

Guillain-Barre syndrome (GBS) is a postinfectious inflammatory polyradiculo-neuropathy characterized bý flaccid paralysis. Antibodies directed against glycolipid structures (gangliosides), which are highly expressed in the peripheral nervous system, are frequently detected in sera from GBS patients. These antibodies interfere with nerve conduction and have been shown to activate phagocytes via IgG receptors (FcgR). These findings support an important role of glycolipid-specific antibodies in the pathogenesis of GBS. ᮊ

Gangliosides, sialic-acid-containing glycosphingolipids are involved in numerous biological processes and play essential roles in severe pathologies, with predilection in those of the central nervous system. Formerly, ganglioside composition and quantity were assessed exclusively by thin-layer chromatographic (TLC), immunochemical, and immunohistochemical methods, which have limited effectiveness being unable to detect minor components in mixtures of high heterogeneity. Increased awareness of the biological importance of gangliosides stimulated the development of analytical methods that are better amenable to complex ganglioside mixtures. More recently, MS in online conjunction with high-performance separation techniques brought a significant progress to the field. This review highlights the state-of-the-art development and application of separation methods online coupled to MS for ganglioside analysis. Most original and successful protocols based on GC-MS, LC-MS, and CE-MS are presented here together with the special instrumental and sample preparation requirements to be met for effective ganglioside separation, detection, and structural identification. Finally, the advantages and downsides of each methodology as well as the perspectives for simplification, standardization, and upgrading are assessed.

The authors reported the neurological disease spectrum associated with autoantibodies against minor gangliosides GM1b and GalNAc-GD1a. IgG and IgM antibody reactivity against gangliosides GM1, GM2, GM1b, GD1a, GalNAc-GD1a and GQ1b was investigated in sera from 7000 consecutive patients who had various neurological conditions. The clinical diagnoses for 456 anti-GM1b-positive patients were Guillain-Barré syndrome (GBS, 71%), atypical GBS with preserved deep tendon reflexes (12%), Fisher syndrome (10%), Bickerstaff's brainstem encephalitis (2%), ataxic GBS (2%) and acute ophthalmoparesis (1%). For 193 anti-GalNAc-GD1a-positive patients, the diagnoses were GBS (70%), atypical GBS (16%), Fisher syndrome (10%) and Bickerstaff's brainstem encephalitis (3%). Of the patients with GBS or atypical GBS, 28% of 381 anti-GM1b-positive and 31% of 166 anti-GalNAc-GD1a-positive patients had neither anti-GM1 nor anti-GD1a antibodies. Of those patients with Fisher syndrome, Bickerstaff's brainstem encephalitis, ataxic GBS or acute ophthalmoparesis, 33% of 67 anti-GM1b-positive, and 52% of 25 anti-GalNAc-GD1a-positive patients had no anti-GQ1b antibodies. Autoantibodies against GM1b and GalNAc-GD1a are associated with GBS, Fisher syndrome and related conditions. These antibodies should provide useful serological markers for identifying patients who have atypical GBS with preserved deep tendon reflexes, ataxic GBS, Bickerstaff's brainstem encephalitis or acute ophthalmoparesis, especially for those who have no antibodies to GM1, GD1a or GQ1b. A method to prepare GM1b was developed. D

A number of polyamine (PA) derivatives of thiosemicarbazone of 1,3-dichloroacetone (TDA) have been prepared and their effect on growth in vivo of tumorigenic but not metastatic cell strain (LY-R) of mouse lymphoma L5178Y has been investigated. Polyamine derivatives of TDA (PDT) were injected i.p. every third day (4 times, 10 or 25 mg/kg per injection) into DBA/2 mice inoculated i.p. or s.c. with LY-R cells. It has been found that disubstituted putrescine (Put), spermidine (Spd) and spermine (Spin) derivatives TDA exhibit a prometastatic activity as indicated by the appearance of solid tumor foci in subcutaneous tissues, liver and spleen. This activity depends mainly on the structure of the PA fragment and the presence of TDA. An increase in lipid bound sialic acid content after treating LY-R cells in vitro and in vivo with a Spin derivative has been found. These findings suggest that disubstituted PA derivatives of TDA and LY-R cells may be a useful model for investigation of the final steps in formation of metastases by lymphoma cells.

This article describes the natural-abundance Fourier-transform carbon-13 nuclear magnetic resonance spectrum, at 67.88 MHz, of aqueous micelles of bovine brain ganglioside G M I of purity greater than 99%. Assignments are given for every carbon nucleus in the molecule, on the basis of a comprehensive study of the relevant mono-, di-, tri-, and polysaccharides, including several containing sialic acid (5-

Paediatric neurodegenerative diseases are frequently caused by inborn errors in glycosphingolipid (GSL) catabolism and are collectively termed the glycosphingolipidoses. GSL catabolism occurs in the lysosome and a defect in an enzyme involved in GSL degradation leads to the lysosomal storage of its substrate(s). GSLs are abundantly expressed in the central nervous system (CNS) and the disorders fre-quently have a progressive neurodegenerative course. Our understanding of pathogenesis in these diseases is incomplete and currently few options exist for therapy.

Phospholipid liposomes composed of phosphatidylcholine (PC) and cholesterol (chol), bearing the sialoglycoprotein glycophorin (GP), are able to effectively bind Sendai virus particles, but not to be lysed by them. Incorporation of gangliosides (gangl) into the above phospholipid vesicles (yielding liposomes composed of PCkhoUgangUGP), although not increasing their ability to interact with Sendai virions, rendered them susceptible to the viral lytic activity. This was inferred from the ability of the virus to induce release of carboxytluoresceirr (CF) upon interaction at 37°C with liposomes composed of PCkhoY gangl/GP. Lysis of liposomes required the presence of the two viral envelope glycoproteins, namely the hemagglutinin/neuraminidase (HN) and the fusion (F) polypeptides, and was inhibited by phenylmethyl sulfonyllluoride (PMSF), dithiothreitol (DTT) and trypsin, showing that virus-induced lysis of PC/choYgangI/GP liposomes reflects the fusogenic activity of the virus.

a b s t r a c t Cellular membranes are highly organized structures with multiple and multi-dimensional levels of order where lipid components are active players. The lipid role is especially evident in rafts, where lipid-driven collective interaction dictates the local structure of a membrane. However, lipids play as well other roles in many aspects of membrane mechanics and function.

Breast cancer is the most common type of cancer, predominantly among women over 20, whereas colo-rectal cancer occurs in both men and women over the age of 50. Chemotherapy of both cancers affect rapidly growing normal as well as cancer cells. Cancer cells are non-apoptotic. Seven anti-cancer agents (cis-platin, Tamoxifen, Melphalan, Betulinic acid, D-PDMP, L-PPMP, and GD3) have been tested with human breast (SKBR3) and colon (Colo-205) carcinoma cells for their apoptotic effect and found to be positive by several assay systems. Colo-205 cells were obtained from ATCC, and the SKBR3 cells were a gift from the Cleveland Clinic. All of these six agents killed those two cell lines in a dose-dependent manner. In the early apoptotic stage (6 h), these cells showed only a flopping of phosphatidylserine on the outer lamella of the plasma membranes as evidenced by the binding of a novel fluorescent dye PSS-380. After 24 h of the treatment, those apoptotic cells showed damage of the plasma as well as the nuclear membrane as evidenced by binding of propidium iodide to the nuclear DNA. DNA laddering assay viewed further breakdown of DNA by 1% agarose gel electrophoresis analysis. It is concluded that during apoptosis the signaling by Mitochondrial Signaling Pathway (MSP) is stimulated by some of these agents. Caspase 3 was activated with the concomitant appearance of its p17 polypeptide as viewed by Westernblot analyses. Incorporation of radioactivity from [U-14 C]-L-serine in total sphingolipid mixture was observed between 2 and 4 micromolar concentrations of most of the agents except cis-platin. However, apoptosis in carcinoma cells in the presence of cis-platin is induced by a caspase 3 activation pathway without any increase in synthesis of ceramide.

Background: Plasmodium vivax merozoite surface protein-1 (MSP-1) is an antigen considered to be one of the leading malaria vaccine candidates. PvMSP-1 is highly immunogenic and evidences suggest that it is target for protective immunity against asexual blood stages of malaria parasites. Thus, this study aims to evaluate the acquired cellular and antibody immune responses against PvMSP-1 in individuals naturally exposed to malaria infections in a malaria-endemic area in the northeastern Amazon region of Brazil. Methods: The study was carried out in Paragominas, Pará State, in the Brazilian Amazon. Blood samples were collected from 35 individuals with uncomplicated malaria. Peripheral blood mononuclear cells were isolated and the cellular proliferation and activation was analysed in presence of 19 kDa fragment of MSP-1 (PvMSP-1 19) and Plasmodium falciparum PSS1 crude antigen. Antibodies IgE, IgM, IgG and IgG subclass and the levels of TNF, IFN-γ and IL-10 were measured by enzyme-linked immunosorbent assay. Results: The prevalence of activated CD4 + was greater than CD8 + T cells, in both ex-vivo and in 96 h culture in presence of PvMSP-1 19 and PSS1 antigen. A low proliferative response against PvMSP-1 19 and PSS1 crude antigen after 96 h culture was observed. High plasmatic levels of IFN-γ and IL-10 as well as lower TNF levels were also detected in malaria patients. However, in the 96 h supernatant culture, the dynamics of cytokine responses differed from those depicted on plasma assays; in presence of PvMSP-1 19 stimulus, higher levels of TNF were noted in supernatant 96 h culture of malaria patient's cells while low levels of IFN-γ and IL-10 were verified. High frequency of malaria patients presenting antibodies against PvMSP-1 19 was evidenced, regardless class or IgG subclass. PvMSP-1 19-induced antibodies were predominantly on non-cytophilic subclasses. Conclusions: The results presented here shows that PvMSP-1 19 was able to induce a high cellular activation, leading to production of TNF and emphasizes the high immunogenicity of PvMSP-1 19 in naturally exposed individuals and, therefore, its potential as a malaria vaccine candidate.

Exogenous sphingomyelin, radiolabelled at the sphingosine moiety, was administered to primary cultures of cerebellar granule cells and astrocytes for different pulse times (20 min-2 h) and the fate of the radioactivity was followed. Ceramide was the main metabolic product in both cells, whereas sphingosine, glucosyl-ceramide and gangliosides GM3 and GD3 were produced only in astrocytes. When endocytosis was prevented and the lysosomal apparatus inactivated, ceramide formation was reduced slightly in granule cells and almost completely blocked in astrocytes, with disappearance of sphingosine, glucosyl-ceramide, GM3 and GD3. These data indicate that (a) ceramide is rapidly produced in cerebellar granule cells and astrocytes, presumably at the level of the plasma membrane in the first cell type, and of the lysosomes in the second one; (b) sphingosine is produced in cerebellar astrocytes by lysosomal sphingomyelin degradation and is partly reused for glucosyl-ceramide and ganglioside biosynthesis.

A method for the assay of neuraminidase in human cultured fibroblasts has been worked out. The substrates, all naturally occurring, were: sialyloligosaccharides (a(2 ~ 3)sialyUactose, a(2-~ 6)sialyllactose, disialyllactose), sialylglycolipids (disialogangliosides GDla and GDlb), sialylglycoproteins and sialylglycopeptides (ovine submaxillary glycoprotein and its pronase-glycopeptides). The method was based on the determination of the enzymically liberated N-acetylneuraminic acid (NeuAc) by a chromatographic-colorimetric microprocedure.

Gangliosides are the main glycolipids of neuronal plasma membranes. Their surface patterns are generated by coordinated processes, involving biosynthetic pathways of the secretory compartments, catabolic steps of the endolysosomal system, and intracellular trafficking. Inherited defects in ganglioside biosynthesis causing fatal neurodegenerative diseases have been described so far almost exclusively in mouse models, whereas inherited defects in ganglioside catabolism causing various clinical forms of GM1-and GM2-gangliosidoses have long been known. For digestion, gangliosides are endocytosed and reach intra-endosomal vesicles. At the level of late endosomes, they are depleted of membrane-stabilizing lipids like cholesterol and enriched with bis(monoacylglycero)phosphate (BMP). Lysosomal catabolism is catalyzed at acidic pH values by cationic sphingolipid activator proteins (SAPs), presenting lipids to their respective hydrolases, electrostatically attracted to the negatively charged surface of the luminal BMP-rich vesicles. Various inherited defects of ganglioside hydrolases, e.g., of ␤-galactosidase and ␤-hexosaminidases, and of GM2-activator protein, cause infantile (with tetraparesis, dementia, blindness) and different protracted clinical forms of GM1-and GM2-gangliosidoses. Mutations yielding proteins with small residual catabolic activities in the lysosome give rise to juvenile and adult clinical forms with a wide range of clinical symptomatology. Apart from patients' differences in their genetic background, clinical heterogeneity may be caused by rather diverse substrate specificities and functions of lysosomal hydrolases, multifunctional properties of SAPs, and the strong regulation of ganglioside catabolism by membrane lipids. Currently, there is no treatment available for neuronal ganglioside storage diseases. Therapeutic approaches in mouse models and patients with juvenile forms of gangliosidoses are discussed.

Aims:  We characterized phenotypically and genotypically root-nodulating bacteria associated with Acacia senegal (L.) Willd. isolated from the soils surrounding A. senegal trees in the dry land area of Senegal.Methods and Results:  The phenotypical and genotypical characterizations we carried out showed a high diversity of A. senegal root-nodulating bacteria. Phenotypic patterns showed adaptations of the rhizobial strains to many environmental stresses such as heat, drought, and salinity. Twelve molecular groups were distinguished by profiles obtained using polymerase chain reaction/restriction fragment length polymorphism techniques from intergenic spacer region rDNA. The highest genetic diversity was found around the A. senegal rhizosphere. Therefore, A. senegal seemed to have a positive influence on occurrence and genotypical diversity of rhizobial populations. Rhizobial isolates obtained in this study belonged phylogenetically to the genera Mesorhizobium and Rhizobium.Conclusions:  Our results provided information about the genetic diversity of the rhizobial strains associated with A. senegal and suggested the adaptability of natural rhizobial populations to major ecological environmental stress within these soil environments.Significance and Impact of the Study:  These results suggested a potential selection of compatible and well adapted strains under stress conditions as inoculants for successful A. senegal growth in arid lands.

Human IgM anti-Gal(/31-3)GalNAc ant,bodies which brad to GMI and GD,b, are imphcated in the pathogenests of predommantly motor neuropathy or motor neuron disease By lmmunofluorescence microscopy, the human ant,bodies tmmunostaln the surface of motor neurons from bovine spinal cord The motor neurons are also immunostalned by cholera tOrah (CT), which is specific for GMI Glycohpld analysis usmg thin-layer chromatography (TLC) and lmmunostalnmg reveals that the relative concentratton of GMI and GDt b m motor neurons ts greatly reduced m compartson to whole spinal cord, and that other motor neuron ganghosldes are unreacttve with the antt-Gal(/31-3)GalNAc antibodies By Western blot analysis, the antibodies react w~th several protem bands ,n motor neuron extracts, and many of the same proteins are also recognized by PNA These data suggest that both glycoprotelns and glycohplds might be targets for anti-Gal(/31-3)GalNAc antlbod,es m spinal motor neurons

Gangliosides from livers of weanling rats were analyzed after 15% partial hepatectomy (PH) and different pre-and post-operative hyberbaric oxygenation (pre-and postHBO). Neu5Ac was the predominant ganglioside-derived sialic acid (>85%) compared to Neu5Gc. Almost identical low total sialic acid content (Neu5Ac + Neu5Gc) of the control and operated nonHBO animals opposed a 6.4-to 7.6-fold increase in pre-and postHBO animals (69.26 and 81.64 pmol/mg wet weight, respectively). NanoESI-QTOF mass spectrometry combined with HPTLC immunostaining revealed GM3(Neu5Ac) and GM3(Neu5Gc) as major gangliosides, correlating with the respective sialic acid concentrations. Minor neolacto-series gangliosides were enhanced in preHBO and postHBO, but GM1-core gangliosides only in preHBO rats. GM2 and GalNAc-GM1b were clearly detectable in oxygenated rats compared to traces in the control and nonHBO animals. These results point at a functional role of gangliosides in liver growth regulation and reconstitution after PH combined with pre-and post-operative HBO treatment.

The aggregative properties of gangliosides in diluted aqueous solutions are discussed on the basis of simple and well.established thermodynamic concepts. Theoretical assumptions are compared with experimental data obtained, mainly by scattering techniques, on GM3, GM2, GM1, GDIa, GalNAc-GDIa, GDIb, GDlb lactone and GTlb gangliosides, all containing ceramide portions of similar composition, and on GMI molecular species containing different well-defined ceramide structures. We also report on mixed aggregates with amphiphilic compounds and on the ganglioside aggregate-soluble protein interaction effects which give rise to very stable lipoproteic complexes of welldefined ganglioside-protein composition.