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E Buchner

Publications and source records attributed to E Buchner.

At least 37 records · Page 2Linked to original sources
PubMed1995

The sap47 gene of Drosophila melanogaster codes for a novel conserved neuronal protein associated with synaptic terminals.

Proteins expressed specifically in neurons and transported to synaptic terminals are likely to constitute important molecular elements of nervous system function. In an effort to characterize synapse-associated proteins (SAPs) of Drosophila, we have isolated from a hybridoma library several monoclonal antibodies (MABs) that selectively stain synaptic terminals in immunohistochemical preparations. MAB nc46 binds to most but not all synaptic terminals of the Drosophila nervous system, it also recognizes a protein with homologous distribution in other dipteran flies and binds to large parts of fish CNS. In Western blots the antibody labels a Drosophila brain protein of 47 kDa and cross-reacts with brain proteins from several species including insects, fish, mouse and man. From these data we conclude that the corresponding gene has been conserved in evolution at least among diptera. Using MAB nc46 and expression cloning we have identified the 'sap47' gene coding for the 'synapse-associated protein of 47 kDa' of Drosophila melanogaster. Sequence analysis of genomic and cDNA clones reveals the intron-exon structure of the gene and characterizes the complete open reading frames of two alternatively spliced transcripts. The sap47 gene is located in 89A8-B3 on chromosome 3R and codes for two almost identical inferred polypeptides of 347 and 351 amino acids with no significant sequence homology to known proteins.

Amino Acid Sequence↗
PubMed1995

Treatment of rat arthritides with clodronate-containing liposomes.

Large multilamellar liposomes containing dichloro-methylene-bisphosphonate (clodronate; Clo), a bisphosphonate that becomes toxic when intracellularly concentrated, were used to therapeutically target macrophages (M phi) in rats with established adjuvant arthritis (AA; i.v. on days 10,11,12) or antigen-induced arthritis (AIA; i.v. or i.a. on 3 h, days 1,2). In established AA, i.v. injection of Clo-liposomes led to significant, long-lasting amelioration of clinical parameters, and to reduced destruction of the ankle joint even several weeks after termination of treatment. In the acute phase of established AIA, intravenous treatment induced transient clinical amelioration, but did not counteract joint destruction. I.a. treatment in AIA was ineffective. Systemic treatment with anti-M phi principles induces amelioration of both AA and AIA; the improvement appears more profound in AA, i.e., the model with a more systemic character. Preliminary data indicate that depletion of M phi occurs in the liver rather than in spleen, draining lymph nodes or synovial membrane. In addition, local treatment with the same principle is ineffective in AIA. Therefore, systemic elimination of M phi in different sites may be crucial for effective therapy of arthritis with anti-M phi agents.

Animals↗
PubMed1995

Induction of flare-up reactions in rat antigen-induced arthritis.

Flare-up reactions were induced in the rat chronic antigen-induced arthritis model (AIA), similar to those in mice and rabbits. After two consecutive immunizations (500 micrograms each, Day -21 and -14) with methylated bovine serum albumin (mBSA) in complete Freund's adjuvant (CFA), a biphasic primary arthritis was induced on Day 0 by intra-articular (i.a.) injection of 100 micrograms mBSA. The acute arthritic phase lasted 1 week, followed by chronic, mild joint swelling. Flare-up could then be induced on Day 40 by a second i.a. injection of 10-100 micrograms mBSA into the knee, with maximal flare-up reaction 2 days following the i.a. injection, and a return to chronic levels within 2 weeks. On Day 6 after induction of the flare-up, the inflamed joint showed massive cartilage and bone destruction; high numbers of alpha beta-T-cell-receptor-positive cells and macrophages, but only a few IL-2-receptor-carrying cells were detected in the inflamed synovial membrane. Induction of a second flare-up, 40 days after the first one, was possible by i.a. injection of 100 micrograms mBSA. Unlike in the mouse model, intravenous injection of up to 10 mg mBSA failed to induce flare-ups in the chronically inflamed joint.

Animals↗
PubMed1994

Paralysis and early death in cysteine string protein mutants of Drosophila.

Multimeric complexes of synaptic vesicle and terminal membrane proteins are important components of the neurotransmitter release mechanism. The csp gene of Drosophila encodes proteins homologous to synaptic vesicle proteins in Torpedo. Monoclonal antibodies demonstrate different distributions of isoforms at distinct subsets of terminals. Deletion of the csp gene in Drosophila causes a temperature-sensitive block of synaptic transmission, followed by paralysis and premature death.

Animals↗
PubMed1994

Presynaptic dysfunction in Drosophila csp mutants.

Cysteine string proteins are synapse-specific proteins. In Drosophila, csp deletion mutants exhibit temperature-sensitive paralysis and early death. Here, we report that neuromuscular transmission is impaired presynaptically in these csp mutant larvae. At 22 degrees C, evoked transmitter release is depressed relative to wild type and rescued controls, and high frequency stimulation of the nerve leads to sporadic failures. At 30 degrees C, stimulus-evoked responses decline gradually before failing completely. When the temperature is returned to 22 degrees C, evoked responses recover. Spontaneous release events persist at both 22 degrees C and 30 degrees C. Since nerve conduction and postsynaptic sensitivity are unaffected, these data indicate that csp mutations disrupt depolarization-secretion coupling. This disruption explains the cellular basis of the temperature-sensitive paralysis of these organisms.

Animals↗
PubMed1993

Histamine is a major mechanosensory neurotransmitter candidate in Drosophila melanogaster.

Histamine is known to be the neurotransmitter of insect photoreceptors. Histamine-like immunoreactivity is also found in a number of interneurons in the central nervous system of various insects. Here, we demonstrate by immunohistochemical techniques that, in Drosophila melanogaster (Acalypterae), most or all mechanosensory neurons of imaginal hair sensilla selectively bind antibodies directed against histamine. The histamine-like staining includes the cell bodies of these neurons as well as their axons, which form prominent fibre bundles in peripheral nerves, and their terminal projections in the central neuropil of head and thoracic ganglia. The specificity of the immunostaining is demonstrated by investigating a Drosophila mutant unable to synthesize histamine. Other mechanosensory organs, such as campaniform sensilla or scolopidial organs, do not stain. In the calypteran flies, Musca and Calliphora, we find no comparable immunoreactivity associated with either hair sensilla or the nerves entering the central nervous system, observations in agreement with earlier studies on Calliphora. Thus, histamine seems to be a major mechanosensory transmitter candidate of the adult nervous system of Drosophila, but apparently not of Musca or Calliphora.

Animals↗
PubMed1991

Organization, promoter analysis and transcriptional regulation of the Staphylococcus xylosus xylose utilization operon.

The Staphylococcus xylosus xyl genes were cloned in Staphylococcus carnosus by complementation to xylose utilization. Xylose isomerase assays under inducing (xylose present) and non-inducing (xylose absent) conditions indicated the presence of a regulated xylA gene on the recombinant plasmid. The nucleotide sequence (4520 bases) revealed three open reading frames with the same polarity. They were identified by sequence homologies as xylR, encoding the Xyl repressor, xylA, encoding xylose isomerase and xylB, encoding xylulokinase. Primer extension analyses indicated constitutive transcription of xylR and xylose-inducible transcription of xylA. Promoter consensus sequences were found upstream of both transcriptional start sites. A transcriptional terminator between xylR and xylA separates the different transcriptional units. Potential regulatory elements were identified by sequence analysis and suggest a repressor-operator mechanism for the regulation of xylAB expression.

Aldose-Ketose Isomerases↗
PubMed1990

Identification of H1 visual interneuron in Drosophila by [3H]2-deoxyglucose uptake during stationary flight.

High-resolution 2-deoxyglucose (2-DG) neuronal activity labeling is used to identify a visual interneuron in Drosophila by its stimulus-specific uptake of [3H]2-DG during stationary flight in a well-characterized behavioral situation. With a single rotating stripe as visual stimulus a neuron is heavily labeled that has not been described in Drosophila before but is homologous to the extensively studied H1 visual interneuron of larger diptera. Labeling of this cell is inconspicuous in Drosophila if the animal is stimulated with a rotating striped drum.

Animals↗
PubMed1990

A cysteine-string protein is expressed in retina and brain of Drosophila.

Antibodies can be used to identify tissue- and stage-specifically expressed genes. A monoclonal antibody MAB ab49 from a hybridoma library screened for immunohistochemical staining in the adult nervous system of Drosophila melanogaster was found to selectively bind to all neuropil regions and to synaptic boutons of motor neurons. In Western blots of homogenized brains the antibody recognizes two proteins of 32 and 34 kD. Using this antibody we have isolated seven cDNA clones that derive from two polyadenylated mRNA splice variants of a gene located at 79E1-2 on polytene chromosomes. The two mRNAs code for two inferred proteins of 249 and 223 amino acids, respectively, which are identical except for their C-terminals and a central deletion of 21 amino acids in the second protein. Both contain a contiguous string of 11 cysteine residues. In situ hybridization to frozen head sections detects expression of this gene in retina and neuronal perikarya. The 32 and 34 kD brain proteins that presumably are localized predominantly in synaptic terminals of photoreceptors and most if not all neurons may correspond to two variant cysteine-string proteins as they are of similar molecular weight and share an antigenic binding site for MAB ab49.

Amino Acid Sequence↗
PubMed1988

Cell-specific immuno-probes for the brain of normal and mutant Drosophila melanogaster. I. Wildtype visual system.

We have screened antibodies for immunocytochemical staining in the optic lobes of the brain of Drosophila melanogaster. Seven polyclonal antisera and five monoclonal antibodies are described that selectively and reproducibly stain individual cells and/or produce characteristic staining patterns in the neuropile. Such antisera are useful for the cellular characterization of molecular and structural brain defects in visual mutants. In the wildtype visual system we can at present separately stain the following: the entire complement of columnar "T1" neurons; a small set of presumptive serotonergic neurons; some 3000 cells that contain and synthesize gamma-amino butyric acid (GABA); and three groups of cells that bind antibodies to Ca2+-binding proteins. In addition, small groups of hitherto unknown tangential cells that send fine arborizations into specific strata of the medulla, and two patterns of characteristic layers in the visual neuropile have been identified by use of monoclonal antibodies generated following immunization of mice with homogenates of the brain of Drosophila melanogaster.

Animals↗
PubMed1988

Honeybee retinal glial cells transform glucose and supply the neurons with metabolic substrate.

The retina of the honeybee drone is a nervous tissue in which glial cells and photoreceptor cells (sensory neurons) constitute two distinct metabolic compartments. Retinal slices incubated with 2-deoxy[3H]glucose convert this glucose analogue to 2-deoxy[3H]glucose 6-phosphate, but this conversion is made only in the glial cells. Hence, glycolysis occurs only in glial cells. In contrast, the neurons consume O2 and this consumption is sustained by the hydrolysis of glycogen, which is contained in large amounts in the glia. During photostimulation the increased oxidative metabolism of the neurons is sustained by a higher supply of carbohydrates from the glia. This clear case of metabolic interaction between neurons and glial cells supports Golgi's original hypothesis, proposed nearly 100 years ago, about the nutritive function of glial cells in the nervous system.

Animals↗
PubMed1984

[3H]2-deoxyglucose mapping of odor-induced neuronal activity in the antennal lobes of Drosophila melanogaster.

Olfactory stimulation results in an enhanced uptake of [3H]2-deoxyglucose in specific glomeruli in the antennal lobes of Drosophila melanogaster. Unilateral stimulation induces activity in receptor axons and lobe interneurons on the ipsilateral side. Collaterals from the receptor axons to the contralateral lobe are also active but stimulate either weak or no postsynaptic activity. This difference in signal transfer properties could be relevant to odor detection by flies.

Animals↗
PubMed1984

Identification of [3H]deoxyglucose-labelled interneurons in the fly from serial autoradiographs.

Using the [3H]deoxyglucose technique we find in the third visual ganglion of the fly, Musca domestica, a number of neuronal profiles whose labelling strongly depends on the direction of visual movement. By reconstruction from serial autoradiographs of semithin sections the three-dimensional morphology of the labelled profiles, we demonstrate that cell bodies, neurites, axons and arborizations of two interneurons are labelled whose homologues in Calliphora have been identified as movement-sensitive centrifugal horizontal cells ('CH-cells'). A set of three other cells whose homologues in Calliphora show similar electrophysiological responses to horizontal movement ('HS-cells') exhibit very little label on either side. It is suggested that the relation between deoxyglucose mapping and physiological activity can be investigated at the cellular level by using this system of fly interneurons.

Animals↗
PubMed1983

Autoradiographic localization of [3H]choline uptake in the brain of Drosophila melanogaster.

We describe the localization of sites for choline uptake in the brain of Drosophila melanogaster by the technique of autoradiography of diffusible substances. After systemic injection of [3H]choline, heavy labelling is found in certain regions of the ventral mid-brain, the antennal mechanosensory system including certain commissures, the olfactory lobes and the antennal glomerular tract. This accumulation of label is sensitive to hemicholinium-3 and can be suppressed by incubation at 0 degrees C. It is proposed that acetylcholine is a major neurotransmitter of the antennal mechanosensory and chemosensory systems of Drosophila.

Acetylcholine↗
PubMed1981

The deoxyglucose method for insects: towards electron microscopical resolution.

The problems of extending the deoxyglucose method for insects to electron microscopical resolution are discussed. It is calculated that several curies of 3H-deoxyglucose per kilogram body weight may be needed for identification of activity in ultra-thin sections. Oral application may be superior to injection. Incorporation of experimental and control stimulus in the same animal seems appropriate. Freeze-drying of Drosophila results in structural preservation sufficient for cell identification in the cervical connective. Autoradiography of ultra-thin sections has not yet been carried out.

Animals↗