Physicochemical characteristics of wheat bran glucuronoarabinoxylans
Schooneveld-Bergmans, M.E.F. ; Dijk, Y.M. van; Beldman, G. ; Voragen, A.G.J. - \ 1999
Journal of Cereal Science 29 (1999). - ISSN 0733-5210 - p. 49 - 61.
Studies on the oxidative cross-linking of feryloylated arabinoxylans from wheat flour and wheat bran
Schooneveld-Bergmans, M.E.F. ; Dignum, M.J.W. ; Grabber, J.H. ; Beldman, G. ; Voragen, A.G.J. - \ 1999
Carbohydrate Polymers 38 (1999). - ISSN 0144-8617 - p. 309 - 317.
Structural features of (glucurono)arabinoxylans extracted from wheat bran by barium hydroxide
Schooneveld-Bergmans, M.E.F. ; Beldman, G. ; Voragen, A.G.J. - \ 1999
Journal of Cereal Science 29 (1999). - ISSN 0733-5210 - p. 63 - 75.
|Cereal arabinoxylans: structure elucidation and enzymatic modification related to cereal technology.
Voragen, A.G.J. ; Gruppen, H. ; Schooneveld-Bergmans, M.E.F. ; Verbruggen, M.A. ; Beldman, G. ; Hilhorst, M.H. ; Huisman, M.M.H. ; Schols, H.A. - \ 1998
In: Cereal Carbohydrates Workshop, Cairns, Australia - p. 21 - 21.
Extraction and partial characterization of feruloylated glucuronoarabinoxylans from wheat bran.
Schooneveld-Bergmans, M.E.F. ; Hopman, A.M.C.P. ; Beldman, G. ; Voragen, A.G.J. - \ 1998
Carbohydrate Polymers 35 (1998). - ISSN 0144-8617 - p. 39 - 47.
Expression of a male accessory gland peptide of Leptinotarsa decemlineata in insect cells infected with a recombinant baculovirus.
Smid, H.M. ; Schooneveld, H. ; Deserno, M.L.L.G. ; Put, B. ; Vlak, J.M. - \ 1998
Journal of Insect Physiology 44 (1998). - ISSN 0022-1910 - p. 255 - 262.
The male accessory glands (MAGs) of Leptinotarsa decemlineata produce an 8kDa peptide, designated Led-MAGP, that is recognized by monoclonal antibody MAC-18. The site of synthesis, amino acid sequence and the gene encoding this peptide have been documented (). The primary structure is homologous to the N-terminal hexa-repeat section of the chicken prion protein (). The biological function of the Led-MAGP has yet to be determined. For further research, large amounts of Led-MAGP is required, both for the production of a more specific antiserum, as well as for application in bio-assays. This paper describes the expression of Led-MAGP in insect cells infected with recombinant baculovirus, and the production of a polyclonal antibody against this recombinant peptide. The peptide was expressed under the control of the polyhedrin promotor. The resulting product was HPLC-purified, and analysis on Western blots immuno-labelled with MAC-18 confirmed that the correct peptide was produced. Purified recombinant peptide was also analyzed by Edman degradation and mass spectrometry; this indicated that it was N-terminally blocked and that the methionine residue at position 7 was oxidized. Large scale production resulted in the formation of aggregations of Led-MAGP, nevertheless a substantial proportion remained in a soluble state and could be harvested. A polyclonal antiserum encoded #87 was produced against recombinant Led-MAGP and its specificity was tested on Western blots of authentic peptide and on LM and EM sections of MAGs. All labelling results were equal to those obtained after MAC-18 labelling. However, antiserum #87 proved to be superior compared to MAC-18, since it recognizes the MAG peptide in normally fed, sexually active males, whereas MAC-18 labelling can only be accomplished after 7 days of starvation of the males. Therefore, the new antiserum #87 enables us to study the transfer dynamics of the Led-MAGP on histological sections.
Schooneveld, H. - \ 1998
Microscopic Anatomy Invertebrates 11B (1998). - p. 467 - 486.
A peptide from the male accessory glands of the Colorado potato beetle
Smid, H.M. - \ 1998
Agricultural University. Promotor(en): L.M. Schoonhoven; H. Schooneveld. - S.l. : Smid - ISBN 9789054858188 - 87
geslachtshormonen - chrysomelidae - androgenen - androsteron - eiwitten - sex hormones - chrysomelidae - androgens - androsterone - proteins
This thesis describes a study of the male accessory glands of the Colorado potato beetle, Leptinotarsa decemlineata (Say). These glands add various substances to the ejaculate. On mating, the ejaculate is transferred to the female, together with the substances from the male accessory glands. The function of these substances is unknown in the case of the Colorado potato beetle. From research on other insect species, we know that some of these substances stimulate the female to oviposit at a higher rate, and to refuse further matings for a certain period. These two effects are known to be evoked by the action of one peptide hormone in the case of Drosophila melanogaster , and this peptide is called sex-peptide. At least part of its activity is thought to be accomplished by stimulation of the corpus allatum (allatotropic) activity, as indicated by in vitro experiments. The activity of the corpora allata is normally under control of some neurons in the brain, the lateral neurosecretory cells, which innervate these glands. These neurons use as yet unidentified peptide hormones as messenger substance, and it is possible that these peptides are similar in structure and activity to sex-peptide.
Our immunohistochemical studies on the Colorado potato beetle give indirect support for the possible dual control of corpus allutm activity. We revealed that some glandular cells in the male accessory glands are labelled by a monoclonal antibody that was raised against the peptides in the lateral neurosecretory cells. The question arises whether the antigen in the accessory glands is indeed identical to the antigen in the lateral neurosecretory cells. In that case, both antigens are involved in stimulation of the corpus allatum activity. The aim of the present study is to compare the antigens in the accessory glands and the lateral neurosecretory cells, and to study the function of the former in more detail (chapter 1).
The antigen in each of the two accessory glands is present in a specific set of approximately 100 dispersed glandular cells. The immuno-reactive cells contain granules with crystalline contents, and these crystals have a rod-like appearance. Such rods are also immuno-labelled in the lumen of the gland (chapter 2).
The antigen in the accessory glands is a peptide of 8 kDa., designated Led-MAGP ( Le ptinotarsa d ecemlineatam ale a ccessory g land p eptide). Part of the amino acid sequence has been determined. Using this structural information the gene encoding this peptide has been identified and thereby the structure of the entire peptide. The peptide is expressed exclusively in the accessory glands, not in the brains. The peptide does not resemble any known peptide hormone, but it shows a considerable degree of similarity to the N-terminus of the chicken prion protein. Prion proteins are at present in the centre of interest since they are involved in certain fatal neurodegenerative diseases in man (Creutzfeldt-Jakob disease) and cattle (scrapie, bovine spongiformic encephalopathies, better known by its acronym BSE) (chapter 3).
Four antigens from the lateral neurosecretory cells have been characterized to determine their relatedness to Led-MAGP. However, the peptides isolated all differ in size and chromatographic properties from Led-MAGP. Our initial interpretation that the antigens from the lateral neurosecretory cells might be identical to Led-MAGP, had therefore to be rejected (chapter 4).
A recombinant baculovirus is constructed, equipped with the gene encoding Led-MAGP. This way large amounts of this peptide are produced in order to study its function. The recombinant Led-MAGP is produced by infection of insect cells cultures with the recombinant baculovirus. Large scale production is hampered by the formation of large aggregates of Led-MAGP. Nevertheless, sufficient peptide has been harvested to produce a new antibody against Led-MAGP. This antibody recognized the authentic peptide with superior specificity, compared with the monoclonal antibody used previously (chapter 5).
Microscopical analysis with the new antiserum reveals the fate of Led-MAGP during copulation. Male and female reproductive tracts were taken from mating couples for immunohistochemical analysis with the new antiserum. The route of the Led-MAGP could be analyzed in detail. Led-MAGP is transferred from the male accessory glands to the spermathecal duct in the female. Led-MAGP most probably diffuses to the hemolymph within minutes after its deposition (chapter 6).
A hypothesis is put forward as to the physiological function of Led-MAGP. This hypothesis is based on the homology of Led-MAGP with the chicken prion protein, and on the observation that it binds hemolymph protein. The N-terminus of the chicken prion protein namely contains 8 hexa-repeats, whereas Led-MAGP has and 7 hexa-repeats that are largely homlogous. Although the biological function of the prion protein itself is unknown, the section with the 8 hexarepeats serves as a signal that induces the uptake of the ch-prp in the endocytosis route. By analogy, Led-MAGP could, by binding to hemolymph proteins, induce the uptake of these proteins by the developing oocytes. This way led-MAGP stimulates the growth of the oocytes on the expense of female hemolymph proteins. In other words, the balance of protein use between maintenance and reproduction, is shifted more towards reproduction. This mechanism would at the same time explain the reduction of female receptivity for mating, as remating will lead to the acquisition of too much Led-MAGP, and thus to overstimulation of reproduction at the expense of other body functions (chapter 7).
A test of the hypothesis that is proposed in chapter 7 awaits methodological improvements. Detection of Led-MAGP in the mated female, by using the specific antiserum is hampered due to cross-reactivity of several female-derived proteins. The tendency of Led-MAGP to aggregate further complicates a functional analysis. Furthermore, the available inbred laboratory strain of the Colorado potato beetle is probably unsuitable for a bioassay on stimulation of oviposition (general discussion).
Nuclear magnetic resonance and methylation analysis-derived structural features of water-extractable arabinoxylans from barley (Hordeum vulgare L.) malts.
Debyser, W. ; Schooneveld-Bergmans, M.E.F. ; Derdelinckx, B. ; Grobet, P.J. ; Delcour, J.A. - \ 1997
Journal of Agricultural and Food Chemistry 45 (1997). - ISSN 0021-8561 - p. 2914 - 2918.
Wheat bran glucuronoarabinoxylans : biochemical and physical aspects
Schooneveld - Bergmans, M.E.F. - \ 1997
Agricultural University. Promotor(en): A.G.J. Voragen; G. Beldman. - S.l. : Schooneveld-Bergmans - ISBN 9789054857167 - 125
graansoorten - maling - Triticum aestivum - tarwe - hexaploïdie - voedsel - voedingsmiddelen - koolhydraten - zetmeel - vezel - polysacchariden - structuur - chemische reacties - cereals - milling - Triticum aestivum - wheat - hexaploidy - food - foods - carbohydrates - starch - fibre - polysaccharides - structure - chemical reactions
Arabinoxylans are present in cereal cell walls and in vitro they have interesting physicochemical properties, such as viscosity and gelation. Although many studies on these properties were reported for wheat flour arabinoxylan, not much research has been directed towards exploitation of these polysaccharides as food gum. For that purpose glucuronoarabinoxylans of wheat bran, a cheap by-product of the cereal industry, were studied with regard to their extractability, their structural and physicochemical properties.
Approximately 50% of the glucuronoarabinoxylans of wheat bran cell wall material were recovered in high purity by barium hydroxide extraction at 70 to 95°C. Delignification or other treatments to open up the cell wall structure were not effective in increasing the yield. The extracted glucuronoarabinoxylans were very diverse in chemical structure and physicochemical properties. About 30% of them had a low degree of substitution, were easily degradable by xylanolytic enzymes and hardly influenced the viscosity of the solvent as a result of extensive aggregation. Over 50% of them had a high degree of substitution, were supposed to contain dimeric branches of arabinose and xylose, were scarcely degradable by xylanolytic enzymes, gave moderate viscosity to solutions and were very effective in stabilizing emulsions. The structure of these glucuronoarabinoxylans could only be speculated upon and it could not be enzymatically modified as a consequence of its complexity and the lack of appropriate enzymes. The remaining glucuronoarabinoxylans either had an intermediate or very high degree of substitution, of which the latter was presumed to be connected to lignin-fragments.
Gel-forming glucuronoarabinoxylans were recovered only in low yield by dilute alkali extraction and subsequent purification was necessary. These feruloylated glucuronoarabinoxylans gelled upon addition of oxidative agents, of which peroxide - peroxidase, glucose - glucoseoxidase - peroxidase and ammonium persulphate were investigated. In comparison with wheat flour arabinoxylans, those of wheat bran appeared to give less flexible networks at high concentration, which was ascribed to their high degree of substitution and high ferulic acid content. Of the dimers formed upon cross-linking, the generally known diferulic acid, being a 5-5 coupled dimer, was only present in relatively low amounts. Dimers, in which the 8-position of the ferulic acid residue is involved were preponderant. The distribution of the dimers was not affected by the type of cross- linking agent or the type of arabinoxylan. However, the presence of lignin fragments in the bran extract was presumed to cause a low ferulic acid recovery upon cross-linking.
A peptide from the male accessory gland in Leptinotarsa decemlineata: Purification, characterization and molecular cloning.
Smid, H.M. ; Koopmanschap, A.B. ; Kort, C.A.D. de; Schooneveld, H. - \ 1997
Journal of Insect Physiology 43 (1997). - ISSN 0022-1910 - p. 355 - 362.
Our interest in the male accessory glands (MAGs) of Leptinotarsa decemlineata was raised recently by our finding that certain cells produce a secretory substance that is recognized by one of our monoclonal antibodies (MAC-18), developed for the immunohistochemical demonstration of peptidergic neurons in the brain. We undertook to isolate this substance, presumably a peptide, to find out more about its role in the post-mating physiology of the recipient of this peptide, the mated female. This paper describes the purification and chemical characterization of the immunoreactive peptide from 100 pairs of male accessory glands. The peptide was purified by two subsequent reversed-phase-HPLC runs, and fractions were analyzed on Western blots that were immunostained by MAC-18. This indicated the presence of an 8 kDa peptide in the MAG. Partial analysis of the N-terminal amino acids by automated Edman degradation revealed a sequence of 40 amino acid residues. To obtain the full amino acid sequence of this peptide, the technique of reverse transcriptase PCR (3'RACE)was used. A PCR product of 350 bp was obtained, which encoded the 3'-end of the mRNA. After cloning and sequencing, this product contained most of the genetic information of the MAG peptide. The PCR product was also used as a probe for screening a eDNA library constructed from mRNA extracted, from MAGs. The nucleotide sequence coding for the signal peptide was: elucidated by 5'RACE. The cDNA and 5'RACE clones were analyzed and sequenced. The sequence of the cDNA clone contained an insert of 411 bp, which agreed well with the mRNA size measured by Northern blotting. Translation of the DNA sequences confirmed the data from partial amino acid sequence analyses and also predicted the remainder of the amino acid sequence. The entire peptide, designated Led-MAGP, consists of 74 residues; its mass was calculated and confirmed by mass spectrometry at 7971 Da. The peptide contains seven imperfect hexa-repeats, and this hexa-repeat sequence shows remarkable similarity to the hexa-repeat section of the chicken prion protein. The physiological function of the peptide has yet to be determined, but the hexa-repeat motif has recently been identified as the signal that induces internalization of the prion protein by coated-pit mediated endocytosis. Possible implications for the control of reproductive activities in L. decemlineata are discussed.
|Insektenfysiologie: eenheid in verscheidenheid.
Schoonhoven, L.M. ; Schooneveld, H. - \ 1995
In: Insekten onderzoeken, een overzicht van vijftig jaar entomologisch onderzoek in Nederland / Koomen, P., Amsterdam : Nederlandse Entomologische Vereniging - p. 67 - 74.
|Midgut of the Colorado potato beetle as a source of peptides with myotropic function.
Muraleedharan, D. ; Smid, H.M. ; Schooneveld, H. - \ 1994
Proceedings of the Section Experimental and Applied Entomology of the Netherlands Entomological Society 5 (1994). - ISSN 1388-8390 - p. 55 - 60.
|Localisation, purification and partial characterisation of a male accessory gland factor by neuropeptide-specific monoclonal antibody MAC-18 in Leptinotarsa decemlineata.
Smid, H.M. ; Schooneveld, H. - \ 1993
In: Insect neurochemistry and neurophysiology / Borkovec, A.B., Loeb, M.J., London : CRC Press - p. 289 - 292.
Serotoninergic innervation of the alimentary canal of the Colorado potato beetle, Leptinotarsa decemlineata: structural and functional aspects.
Haeften, T. van; Smid, H.M. ; Schooneveld, H. - \ 1993
Cell and Tissue Research 273 (1993). - ISSN 0302-766X - p. 475 - 485.
|Proctolin-mediated control of hindgut contractions in the Colorado potato beetle: immunohistochemistry and novel bioassay studies.
Schooneveld, H. ; Smid, H.M. ; Haeften, T. van - \ 1993
Proceedings of the Section Experimental and Applied Entomology of the Netherlands Entomological Society 4 (1993). - ISSN 1388-8390 - p. 103 - 108.
Location and function of serotonin in the central and peripheral nervous system of the Colorado potato beetle
Haeften, T. van - \ 1993
Agricultural University. Promotor(en): L.M. Schoonhoven; H. Schooneveld. - Heteren : Van Haeften - ISBN 9789054851417 - 113
chrysomelidae - neuropeptiden - chrysomelidae - neuropeptides
In this thesis we have localized serotoninergic neurons in the central and peripheral nervous system of the Colorado potato beetle, Leptinotarsa decemlineata by means of immunohistochemistry with a specific antiserurn to serotonin and assessed the possible role of these neurons in feeding physiology. Emphasis was laid on the location of serotoninergic neurons involved in: (1) channelling of sensory information from antennal and gustatory sensory systems to the central nervous system; (2) the central organization of the serotoninergic neuron system providing information on possible central processing of this information; and the routes of innervation of possible target organs.
We have shown that about 200 serotoninergic neurons are present in the cerebral ganglion complex of the beetle, representing interneurons serving short- and long range communication. These neurons were grouped according to their location, number, and distribution of their processes. Clusters of paired protocerebral neurons appeared to be responsible for left-right communication within the brain and are the sole source of immunoreactivity in the central complex and the corpora pedunculata. Other neurons in the optic lobes and the deutocerebrum are likely to play an important role in the processing of visual and olfactory information respectively. This serotoninergic network in the brain does not project to other parts of the central nervous system and has the appearance of an individual serotoninergic neural unit. No neurons with a secretory function are present in the cerebral ganglion complex, nor are there structural indications that serotoninergic neurons are involved with the control of peptidergic neurosecretory neurons in the protocerebrum ( Chapter 2 )
In the remainder of the central nervous system, the ventral nerve cord, altogether 74 serotoninergic neurons were found and their organization pattern enabled us to group them into five neuron classes. Two paired segmental twin interneurons are present in each ganglion or neuromere. These neurons have extensive dendritic arborizations in the contralateral hemisphere of the ganglion, and small arborization close to the perikaryon. Their axons take a contra- and ipsilateral course to more frontally and/ or caudally located ganglia. The distribution of processes is indicative of a division of labour among these neurons. The intersegmental projection are indicative of a function in interganglionic communication, whereas the dendritic projections suggest a function in the coordination of left-right neural activity within the ganglia. Four large frontal secretory neurons are present in the suboesophageal ganglion with axons projecting to a diffuse neurohemal system on oesophageal nerves. A pair of large caudal efferent neurons in the terminal ganglion send their processes in the proctodaeal nerves and innervate the proximal part of the hindgut. The function of miniature and terminal neurons is unknown. The distribution pattern of serotonin-like immunoreactivity enabled us to distinguish three separate putative functional units. The function of the caudal functional unit might be the synaptic control of caudal neurons innervating the alimentary canal, the function of the other two units is unknown ( Chapter 3 ).
The presence of serotoninergic axons in the proctodaeal nerves indicated that the gut might be under serotoninergic control. By means of immunohistochemistry, it was shown that the alimentary canal of the beetle receives innnervation from two separate sources. Large efferent neurons in both the stomatogastric and central nervous system innervate the gut. Four neurons in the frontal ganglion have axons which run via the recurrent nerve to the circular and longitudinal muscles of the fore- and anterior midgut and supply the surface of these muscles with neurohemal axon swellings. The posterior midgut is devoid of immunoreactivity. The longitudinal muscles of the hindgut are supplied by the two caudal neurons described in Chapter 3 . Electron-microscopical inspections of the axon swellings showed that exocytosis of immunolabelled vesicles occurs at some distance from the muscles fibres, indicating that the gut muscles might be under neurohormonal control. No serotoninergic synapses are observed on muscle fibres. A possible serotoninergic neurohormonal control of gut muscles, was confirmed in a bioassay. It appeared that administration of graded dosages of serotonin to the incubation medium has a clear inhibitory effect on spontaneous contractions of hindguts in vitro at concentrations of 10 -8-10 -8M. This effect was dose-dependent ( Chapter 4 ).
Other organs might be under serotoninergic control as well. Two diffuse neurohemal systems for serotonin are present in the head of the beetle. Axons of four secretory neurons in the suboesophageal ganglion, described in Chapter 3 , enter the ipsilateral mandibular nerve and cover the surface with a dense network of immunoreactive swellings. Two efferent neurons in the frontal ganglion have processes that run into the frontal connectives. Here, the axons emerge and form a similar network of axon swellings on the surface of the labro-frontal, pharyngeal, and antennal nerves, and on the frontal ganglion. Electron microscopy showed that these axon swellings are located outside the impermeable neural sheath, surrounding the nerves, and hence in close contact with the hemolymph. Next to this neurohemal release, a targeted release of serotonin occurs near the muscles of labrum, mandibles, pharynx, and salivary glands, indicating that these organs are under serotoninergic control ( Chapter 5 ).
We have investigated the presence of serotoninergic sensory neuronal cell bodies in sensilla on labial and maxillary palps, galea, ventral labrum, tarsi, and compound eyes. It appeared that no afferent serotoninergic neurons are present in the peripheral nervous system of the beetle ( Chapter 6 ).
The studies presented in this thesis show that the biogenic amine serotonin (5- hydroxytryptamine) is a ubiquitous and versatile neuroactive substance in both the central and peripheral nervous system of the Colorado potato beetle. In the central nervous system it is present in interneurons serving intra- and interganglionic communication. Here, it probably functions as a neurotransmitter and/or neuromodulator. A small number of serotoninergic neurons release serotonin, via elaborate ways, as a neurohormone into the hemolymph and/or close to their target organs.
In this thesis we have provided evidence that serotoninergic neurons are involved in the regulation of some aspects of feeding physiology at both the central and peripheral level. In the central nervous system, several serotoninergic interneurons, i.e. those in the cerebral ganglion complex, participate in the channelling and the central processing of antennal and optic information, whereas other interneurons, i.e. those in the ventral nerve cord, are part of functional neural units which are proposed to control efferent neurons, e.g. the caudal neurons innervating the hindgut. Serotoninergic neurosecretory neurons are involved in control of gut functioning, as shown in immunohistochemical and bioassay studies. Another class of efferent neurosecretory neurons were shown to innervate salivary glands and muscles of labrum, mandibles, and anterior pharynx, indicating that these organs might also be under serotoninergic control.
Diffuse serotoninergic neurohemal systems associated with cerebral and suboesophageal nerves in the head of the Colorado potato beetle Leptinotarsa decemlineata.
Haeften, T. van; Schooneveld, H. - \ 1993
Cell and Tissue Research 273 (1993). - ISSN 0302-766X - p. 327 - 333.
|Book review: Morphogenetic hormones of arthropods. Vol 3. Roles in histogenesis, organogenesis and morphogenesis, A.P. Gupta (ed.). Rutgers Univ. Press, New Bruswick, New Jersey, 635 pp.
Schooneveld, H. - \ 1992
Entomologia Experimentalis et Applicata 65 (1992). - ISSN 0013-8703 - p. 307 - 308.
Male accessory sex glands contain a new class of exocrine peptidergic cells in Leptinotarsa decemlineata (Say), identified with the neuropeptide-specific monoclonal antibody MAC-18.
Smid, H.M. ; Schooneveld, H. - \ 1992
Invertebrate reproduction and development 21 (1992). - ISSN 0792-4259 - p. 141 - 148.