Is the number of antennal plate organs (sensilla placodea) greater in hygienic than in non-hygienic Africanized honey bees?

Hygienic behavior is a desirable trait in honey bees (Apis mellifera L.), as hygienic bees quickly remove diseased brood, interrupting the infectious cycle. Hygienic lines of honey bees appear to be more sensitive to the odors of dead and diseased honey bee brood, and Africanized honey bees are generally more hygienic than are European honey bees. We compared the number of sensilla placodea, antennal sensory structures involved in the perception of odor, in 10 bees from each of six hygienic and four non-hygienic colonies of Africanized honey bees. The sensilla placodea of three of the terminal segments (flagellomeres) of the right antenna of each bee were counted with a scanning electron microscope. There were no significant differences in the mean numbers of sensilla placodea between the hygienic and non-hygienic bees, though the variance was higher in the hygienic group. Flagellomere 4 had significantly more sensilla placodea than flagellomeres 6 and 8. However, there was no significant difference between the other two flagellomeres. As hygienic bees are capable of identifying dead, injured, or infested brood inside a capped brood cell, sensilla placodea probably have an important role in enabling worker bees to sense sick brood. However, we did not find greater numbers of this sensory structure in the antennae of hygienic, compared to non-hygienic Africanized honey bees

Abnormal expression and glycosylation of the large and small isoforms of myelin-associated glycoprotein in dysmyelinating quaking mutants.

The relative expression of large (L) and small (S) isoforms of the myelin-associated glycoprotein (MAG) and their glycosylation were compared in developing spinal cord of quaking and control mice. Using antisera specific for L- and S-MAG, respectively, it was shown that S-MAG is the principal isoform in quaking mice at all ages between 13 and 72 days, although L-MAG was just detectable by western blotting at the early ages. Both L- and S-MAG have higher apparent molecular weights in quaking mice than in controls. Experiments involving lectin binding and glycosidase treatment demonstrated that the higher molecular weight of MAG in the quaking mutant was due to a higher content of N-acetylneuraminic acid residues linked alpha 2-3 to galactose as well as to more branching of oligosaccharide moieties indicated by a higher content of subterminal galactose residues. The total sialic acid measured by HPAE-chromatography in purified quaking MAG was 40% higher than in control MAG. By contrast, quaking MAG contained less of the adhesion-related, HNK-1 carbohydrate epitope. Another difference was that a lower molecular weight form of MAG with predominantly high mannose oligosaccharides was prominent in young quaking mice, but not in controls. The abnormalities of MAG expression related to splicing of its mRNA and glycosylation may contribute to the myelin pathology in quaking mutants.

Detection of antiviral and antitumoral fractions of Chenopodium amaranticolor leaf extract.

Based on the fact that Chenopodium amaranticolor extracts showed inhibitory activity against tobacco mosaic virus (TMV) and Ehrlich tumour (EA), tests were carried out to investigate whether the antiviral and antitumoral activity were caused by the same compounds. When the extract was purified by CM Sephadex C-25 column, after precipitation with 90% ammonium sulphate, twenty active fractions against TMV and two pools of fractions active against EA were obtained. Only one fraction with high absorbance values at 260 and 280 nm was able to inhibit both TMV and EA. When the extract was purified by Bio Gel P-60 column two active fractions against TMV and EA were obtained, suggesting that they were contained in the 0.01 M fraction of the CM Sephadex column. It is suggested that C. amaranticolor leaf extract contained at least two protein-like substances manifesting antiviral and antitumoral activity.

The myelin-associated glycoprotein is phosphorylated in the peripheral nervous system.

Phosphorylation of the myelin-associated glycoprotein (MAG) in the peripheral nervous system is demonstrated by immunoprecipitation from myelin proteins radiolabeled in vivo, in nerve slices and in a cell-free system. Phosphoamino acid analysis of immunoprecipitated MAG revealed the presence of radioactivity in phosphoserine, but not in phosphothreonine or phosphotyrosine. Only the shorter isoform of MAG (S-MAG) was detected by immunostaining of nitrocellulose sheets with anti-MAG anti-serum after enzymatic deglycosylation of immunoprecipitated MAG labeled in nerve slices. Autoradiography of the same Western blots revealed that most of the radioactive phosphate was in S-MAG, demonstrating that the polypeptide backbone of S-MAG is phosphorylated in the PNS.

Myelin-associated glycoprotein (MAG) and rat brain-specific 1B236 protein: mapping of epitopes and demonstration of immunological identity.

The myelin-associated glycoprotein (MAG) and the brain 1B236 protein are 100-kDa glycoproteins containing 30% carbohydrate that exist in two developmentally regulated forms and are specific to the nervous system. Recent cDNA cloning experiments in several laboratories using primarily immunological means of identification have determined the complete primary sequence of a rat brain glycoprotein that seems to correspond to both MAG and 1B236, suggesting that these proteins are identical. However, MAG was previously considered to be an oligodendrocyte/myelin specific component in the CNS at all ages, whereas 1B236 was thought to be primarily a neuronal component in adult rats but synthesized by oligodendrocytes at the time of active myelination. The composite term 1B236/MAG was proposed to describe the molecule identified by the cDNAs. In order to explore further the relationship between MAG and 1B236, as well as their developmentally regulated forms, experiments were carried out on rat samples utilizing synthetic peptides corresponding to sequences throughout the 1B236 molecule, antisera raised to synthetic peptides in the C-terminus of 1B236 that distinguish between the two developmentally regulated forms, and well-characterized polyclonal and monoclonal antibodies raised to purified MAG. Epitope mapping demonstrated that reactive sites were distributed throughout the extracellular and intracellular domains of 1B236/MAG. Only antibodies reacting with the smaller of the two forms of 1B236/MAG detected the glycoprotein in the peripheral nervous system. Both anti-MAG and anti-1B236 antibodies revealed a drastic reduction of the level of 1B236/MAG in 25-day-old myelin-deficient rats and in adult quaking mice, and both types of antibodies revealed a slight shift of 1B236/MAG toward higher apparent Mr in quaking mice as had previously been reported for MAG. The results indicate that MAG and 1B236 are almost certainly identical since they cannot be distinguished immunologically by the reagents available and that quantitatively most of the glycoprotein is associated with oligodendrocytes and myelin rather than neurons at all ages.

Two forms of 1B236/myelin-associated glycoprotein, a cell adhesion molecule for postnatal neural development, are produced by alternative splicing.

The structures of two rat brain-specific 1B236 mRNAs, alternative splice products from a single gene regulated differently during postnatal brain development, were deduced from full-length cDNA clones. The 626- and 582-amino acid-long encoded proteins are indistinguishable from two forms of myelin-associated glycoprotein, a cell adhesion molecule involved in axonal-glial and glial-glial interactions in postnatal brain development, particularly in myelination. The two proteins share a single membrane-spanning domain and a glycosylated N terminus but differ in the structures of their C termini. The N terminus consists of five domains related in sequence to each other and to immunoglobulin-like molecules, especially the neural cell adhesion molecule N-CAM, suggesting a common structure for cell adhesion molecules.

Myelin-associated glycoprotein shares an antigenic determinant with a glycoprotein of human melanoma cells.

A sulfated 100K-dalton glycoprotein has been shown to be released into the culture medium of melanoma cells. Monoclonal antibodies 10C5 and 11B5, which were raised to human melanoma cells, as well as HNK-1 bind to this glycoprotein. It is shown here that mouse anti-myelin-associated glycoprotein (MAG) carbohydrate antibodies raised to human MAG and a human IgM paraprotein associated with neuropathy also bind to the same 100K molecule. However, anti-MAG antibodies recognizing peptide epitopes do not appear to react with this glycoprotein of melanoma cells, a result suggesting that its similarity to MAG is restricted to shared carbohydrate moieties. The anti-melanoma antibodies (10C5 and 11B5) resemble HNK-1 in binding to MAG and to some 19-28K-dalton glycoproteins and sulfated, glucuronic acid-containing sphingoglycolipids of the peripheral nervous system (PNS). In addition, the anti-melanoma antibodies cross-react with neural cell adhesion molecule (N-CAM), an observation emphasizing the shared antigenicity between MAG and other adhesion molecules. The results demonstrate that the anti-melanoma antibodies fall into a class of monoclonal antibodies (including HNK-1, human IgM paraproteins associated with neuropathy, anti-human MAG antibodies, and L2 antibodies) that are characterized by reactivity against related carbohydrate determinants shared by human MAG, N-CAM, and several protein and lipid glycoconjugates of the PNS.

Molecular specificity of L2 monoclonal antibodies that bind to carbohydrate determinants of neural cell adhesion molecules and their resemblance to other monoclonal antibodies recognizing the myelin-associated glycoprotein.

L2 monoclonal antibodies and HNK-1 have been shown to bind to related carbohydrate determinants in the myelin-associated glycoprotein (MAG) and several adhesion molecules of the nervous system including neural cell adhesion molecule (N-CAM), L1 and J1. It is shown here that MAG is the principal component in human white matter binding the L2 antibodies, but the most prominent antigens with the L2 epitopes in human gray matter are of higher Mr. It is also shown that the L2 antibodies resemble HNK-1 in binding to some 19-28 kDa glycoproteins and some sulfated, glucuronic acid-containing sphingoglycolipids of the peripheral nervous system (PNS). In addition, monoclonal and polyclonal antibodies raised to human MAG are shown to cross react with bovine N-CAM due to the presence of common carbohydrate constituents. The results further emphasize the shared antigenicity between MAG, N-CAM and other adhesion molecules. In addition, they demonstrate that the L2 antibodies belong to a family of monoclonal antibodies (including HNK-1, human IgM paraproteins associated with neuropathy, and others) that are characterized by reactivity against carbohydrate determinants shared by human MAG, the 19-28 kDa glycoproteins of the PNS and the sulfated, glucuronic acid-containing sphingoglycolipids of the PNS.

Gangliosides in axolemmal and synaptic membrane fractions from developing rats: effects of maternal ethanol consumption on offspring.

Previous work from this laboratory has shown that in utero exposure to ethanol significantly alters the synthesis of glycoproteins in synaptic, axolemmal, and myelin membranes from developing rats. In an attempt to determine whether in utero exposure to ethanol similarly alters the synthesis of other glycoconjugates involved with cell-cell interactions, the present study examined the influence of chronic maternal ethanol consumption prior to parturition on the content and synthesis of gangliosides in axolemmal and synaptic plasma membranes from developing rats. The results demonstrate that, in contrast to central nervous system glycoproteins, synaptic and axolemmal glycolipids are minimally affected by in utero exposure to ethanol. At all ages examined (17 to 34 days of age), the offspring of control and ethanol-treated rats had a comparable distribution of radiolabel among synaptic and axolemmal gangliosides, a normal concentration of ganglioside sialic acid in synaptic plasma membranes, and a near-normal distribution of sialic acid among synaptic gangliosides. The present study provides evidence which indicates that the radiolabeling patterns of axolemmal and synaptic membrane gangliosides are similar. Specifically, the most heavily labeled synaptic and axolemmal gangliosides were GT1b (20-37% of the total radioactivity) and GD1a (20-32%). A smaller proportion of radioactivity was associated with GD1b (approximately 11-16%), GM1 (5-10%), and GQ1b (4-11%), as well as with GD3 and the other monosialogangliosides (less than 5%). During the age period examined the proportion of radioactive GT1b increased in both membrane fractions.

Generation and characterization of mouse monoclonal antibodies to the myelin-associated glycoprotein (MAG).

A panel of mouse monoclonal antibodies to rat and human myelin-associated glycoprotein (MAG) was developed. Normal mice were unresponsive to rat MAG, and successful immunization with rat MAG was only achieved in autoimmune NZB mice. By contrast, all strains of mice were responsive to human MAG. The monoclonal antibodies developed differ with respect to immunoglobulin type, their specificity for human and/or rat MAG, and their recognition of protein or carbohydrate epitopes in MAG. In general, the antibodies that react with the protein backbone recognize both rat and human MAG, whereas a large number of the monoclonal antibodies recognize a carbohydrate determinant in human MAG that is not in rat MAG. Immunocytochemical staining of adult human spinal cord with the monoclonal antibodies resulted in periaxonal staining of myelin sheaths similar to that produced by well-defined, rabbit, polyclonal anti-MAG serum. In addition, the antibodies recognizing carbohydrate determinants in human MAG strongly stained oligodendrocyte cytoplasm. These monoclonal antibodies will be of value for the further chemical and biological characterization of MAG.

Murine monoclonal antibodies to the myelin-associated glycoprotein react with large granular lymphocytes of human blood.

Monoclonal antibodies prepared to human myelin-associated glycoprotein were shown to react with a population of human peripheral blood mononuclear cells. The population is similar to the large granular lymphocytes or natural killer cells defined by antibody Leu 7 (also called HNK-1). The population also includes cells exhibiting the Leu 2 marker for suppressor/cytotoxic T cells. The results indicate a shared antigenicity between the nervous system and the immune system and may be relevant to the pathogenesis of demyelinating diseases.

Synaptic membrane phospholipids: effects of maternal ethanol consumption.

The cholesterol and phospholipid content and phospholipid composition were determined in synaptic membranes from the 17- to 31-day-old offspring of rats that were pair-fed either a control or 6.6% (v/v) ethanol liquid diet on a chronic basis prior to parturition. At all ages examined, the major synaptic membrane phospholipid was phosphatidyl choline (greater than 40%). Other prominent synaptic membrane phospholipids included phosphatidyl ethanolamine (approximately 17 to 21%), ethanolamine plasmalogen (approximately 5 to 16%), and phosphatidyl serine (approximately 13%). Smaller proportions of sphingomyelin (4 to 7%), phosphatidyl inositol (approximately 1%), and phosphatidic acid (approximately 1%) were detected. Between 17 and 31 days of age, there was a significant decrease in the proportion of phosphatidyl choline and a significant increase in the proportion of ethanolamine plasmalogen. When the offspring of control and ethanol-treated rats were compared, no significant differences were found in either the yield of synaptic membrane protein, or in the concentration of synaptic membrane cholesterol and total phospholipid. However, the proportion of ethanolamine plasmalogen was significantly decreased in the 24-day-old offspring of ethanol-treated rats, suggestive of a delay in the normal development-related increase of this lipid. In addition, there was a small increase in the proportion of sphingomyelin in the 31-day-old offspring of ethanol-treated rats.

A human lymphocyte antigen is shared with a group of glycoproteins in peripheral nerve.

The monoclonal antibody HNK-1 binds to a carbohydrate determinant in the myelin-associated glycoprotein (MAG) and other glycoproteins of human peripheral nerve. Some glycoproteins of lower Mr than the major P0 glycoprotein of myelin appear to bind more antibody than MAG. These glycoproteins electrophorese in the Mr range of 20,000 to 26,000 and are present in the purified myelin fraction. The results indicate that an antigen on the surface of a subset of lymphocytes is shared with a group of glycoproteins in human peripheral nerve. The antigen appears to be similar to that recognized by IgM paraproteins associated with a type of neuropathy.

Myelin gangliosides in developing rats: the influence of maternal ethanol consumption.

The present study examined myelin gangliosides in the developing offspring of rats that were pair-fed control or ethanol liquid diets prior to and during gestation. Between 17 and 31 days of age, we observed an increase in the proportion of GM1 in myelin (from 15% to 38% of ganglioside sialic acid) and a decrease in the proportion of GT1b (from 26% to 4%). GM4 was detected at all ages examined. Between 17 and 31 days of age, there was an increase in the proportion of N-acetylmannosamine-derived radioactivity associated with GM1 (from 16% to 22%) and GM4 (from 5% to 13%), and a decrease in that associated with GT1b (from 24% to 4%). Small, but significant (p less than 0.05), developmentally related differences were found in GD2 and GD3. Detection of GM4 in myelin of young rats in the present study appears to depend on the use of nonpartitioning methods of ganglioside extraction. Although the distribution of myelin gangliosides and radioactivity was near-normal in ethanol-treated pups, there was a consistent decrease in the proportion and radioactivity associated with the major myelin ganglioside, GM1.

Maternal ethanol consumption and synaptic membrane glycoproteins in offspring.

The present study was undertaken to assess the influences of chronic maternal ethanol consumption, prior to and during gestation, on the development of synaptic plasma membranes (SPMs) and on the synthesis of SPM glycoproteins in offspring. Comparisons were made between animals whose mothers were pair-fed a control or 6.6% (v/v) ethanol liquid diet in which protein accounted for either 18% (original) (C & E) or 21% (revised) (*C & *E) of the calories. In addition, groups of pups that were either cross-fostered (*C & *E) with chow-fed surrogate mothers or reverse cross-fostered (offspring of chow-fed mothers with *C & *E mothers) were examined. Ethanol and matched (same dietary group) control pups had comparable brain and body weights, brain protein content, and yield of SPM proteins during the 10-24 day age period examined. However, the yield of SPM proteins from ethanol and control offspring of and/or reared by the three groups of rat mothers that received the *E and *C liquid diets was greater than that of the offspring of rats that were fed the original diets. This suggests that the original diets were not nutritionally adequate for pregnant rats. Despite the fact that the content of SPM proteins was comparable in ethanol and matched control pups, the offspring of ethanol-treated rats had an abnormal distribution of [3H]- or [14C]-fucose-derived radioactivity among SPM glycoproteins. The SPM abnormalities were most severe in the non-cross-fostered offspring of E rats. No SPM glycoprotein abnormalities were found in the reverse cross-fostered group. The results of the present study demonstrate that chronic maternal ethanol consumption prior to parturition has a severe effect on the synthesis of SPM glycoproteins in developing offspring without affecting the content of SPMs per se. It also demonstrates the importance of optimizing the composition of liquid diets used to feed pregnant rats.

Circulating immune complexes in neurologic disease.

Sera from patients with multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), subacute sclerosing panencephalitis (SSPE), and myasthenia gravis (MG) were assayed for immune complexes. Three techniques were used: a modified Raji cell assay, the 125I-Clq polyethyleneglycol assay, and a solid-phase clq assay. Immune complex levels were elevated in sera of some patients with MS, ALS, and SSPE, but the elevations were modest when compared with active systemic lupus erythematosus (SLE). In some cases, abnormalities were detected in only one assay system; in other cases, abnormalities were detected by two or three assay systems. In MS, immune complex elevations correlated with active disease and with decreased suppressor cell activity. Of two ALS patients with antecedent poliomyelitis, one had markedly increased levels of immune complexes in two assays. In MG, levels of immune complexes did not differ from those of controls.

The absence of unique kainic acid-like molecules in urine, serum, and CSF from Huntington's disease patients.

By means of a sensitive competition assay, serum, urine, and CSF from patients with Huntington's disease (HD) and controls were tested for the presence of molecules capable of displacing radioactive kainic acid (KA) from rat brain receptors. No difference was found between HD and control samples. It is unlikely that systemic production of an endogenous toxin structurally related to KA occurs in HD.

Detection of in vivo stimulated cerebrospinal-fluid lymphocytes by flow cytometry in patients with multiple sclerosis.

To examine the immune response in the central nervous system in patients with multiple sclerosis (MS), we characterized the cell-cycle phase of lymphocytes from cerebrospinal fluid. Cells were stained with acridine orange, and both RNA and DNA content were determined by flow cytometry. Although most cells were in the quiescent phase of the cycle, a significant increase was seen in the percentage of cells in the first stage of the proliferative cycle (G1 phase) when 21 samples of cerebrospinal fluid from 17 patients with MS were compared with samples from 21 controls (P < 0.001). Stimulated cells in the first stage of the cycle were seen in all categories of MS: active, progressive, or stable. In addition, increased numbers of cells in the second stage of the cycle (S phase) were seen in six specimens from patients with MS, five of whom had actie disease, but no increases were seen in controls (P < 0.02). These data indicate that stimulated lymphocytes were present in the cerebrospinal fluid durng all phases of MS and that stimulation becomes more intense during an acute exacerbation.