Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Texture of cellulose microfibrils of root hair cell walls of Arabidopsis thaliana, Medicago truncatula, and Vicia sativa
Akkerman, M. ; Franssen-Verheijen, M.A.W. ; Immerzeel, P. ; Hollander, L. den; Schel, J.H.N. ; Emons, A.M.C. - \ 2012
Journal of Microscopy 247 (2012)1. - ISSN 0022-2720 - p. 60 - 67.
cortical microtubules - nodulation factors - geometrical model - plasma-membrane - tip growth - deposition - deformation - microscopy - alignment - plants
Cellulose is the most abundant biopolymer on earth, and has qualities that make it suitable for biofuel. There are new tools for the visualisation of the cellulose synthase complexes in living cells, but those do not show their product, the cellulose microfibrils (CMFs). In this study we report the characteristics of cell wall textures, i.e. the architectures of the CMFs in the wall, of root hairs of Arabidopsis thaliana, Medicago truncatula and Vicia sativa and compare the different techniques we used to study them. Root hairs of these species have a random primary cell wall deposited at the root hair tip, which covers the outside of the growing and fully grown hair. The secondary wall starts between 10 (Arabidopsis) and 40 (Vicia) µm from the hair tip and the CMFs make a small angle, Z as well as S direction, with the long axis of the root hair. CMFs are 3–4 nm wide in thin sections, indicating that single cellulose synthase complexes make them. Thin sections after extraction of cell wall matrix, leaving only the CMFs, reveal the type of wall texture and the orientation and width of CMFs, but CMF density within a lamella cannot be quantified, and CMF length is always underestimated by this technique. Field emission scanning electron microscopy and surface preparations for transmission electron microscopy reveal the type of wall texture and the orientation of individual CMFs. Only when the orientation of CMFs in subsequent deposited lamellae is different, their density per lamella can be determined. It is impossible to measure CMF length with any of the EM techniques.
Golgi body motility in the plant cell cortex correlates with actin cytoskeleton organization
Akkerman, M. ; Overdijk, O. ; Schel, J.H.N. ; Emons, A.M.C. ; Ketelaar, T. - \ 2011
Plant and Cell Physiology 52 (2011)10. - ISSN 0032-0781 - p. 1844 - 1855.
arabidopsis root hairs - nod factors induce - class-xi myosins - cortical microtubules - latrunculin b - pollen-tube - growth - elongation - expansion - reveals
The actin cytoskeleton is involved in the transport and positioning of Golgi bodies, but the actin-based processes that determine the positioning and motility behavior of Golgi bodies are not well understood. In this work, we have studied the relationship between Golgi body motility behavior and actin organization in intercalary growing root epidermal cells during different developmental stages. We show that in these cells two distinct actin configurations are present, depending on the developmental stage. In small cells of the early root elongation zone, fine filamentous actin (F-actin) occupies the whole cell, including the cortex. In larger cells in the late elongation zone that have almost completed cell elongation, actin filament bundles are interspersed with areas containing this fine F-actin and areas without F-actin. Golgi bodies in areas with the fine F-actin exhibit a non-directional, wiggling type of motility. Golgi bodies in areas containing actin filament bundles move up to 7 µm s-1. Since the motility of Golgi bodies changes when they enter an area with a different actin configuration, we conclude that the type of movement depends on the actin organization and not on the individual organelle. Our results show that the positioning of Golgi bodies depends on the local actin organization
Caspase inhibitors affect the kinetics and dimensions of tracheary elements in xylogenic Zinnia (Zinnia elegans) cell cultures
Twumasi, P. ; Iakimova, E.T. ; Qian, T. ; Ieperen, W. van; Schel, J.H.N. ; Emons, A.M.C. ; Kooten, O. van; Woltering, E.J. - \ 2010
BMC Plant Biology 10 (2010). - ISSN 1471-2229
tomato suspension cells - mesophyll-cells - hypersensitive response - vascular development - dna fragmentation - serine proteases - plant caspases - nuclear-dna - death - differentiation
BACKGROUND: The xylem vascular system is composed of fused dead, hollow cells called tracheary elements (TEs) that originate through trans-differentiation of root and shoot cambium cells. TEs undergo autolysis as they differentiate and mature. The final stage of the formation of TEs in plants is the death of the involved cells, a process showing some similarities to programmed cell death (PCD) in animal systems. Plant proteases with functional similarity to proteases involved in mammalian apoptotic cell death (caspases) are suggested as an integral part of the core mechanism of most PCD responses in plants, but participation of plant caspase-like proteases in TE PCD has not yet been documented. RESULTS: Confocal microscopic images revealed the consecutive stages of TE formation in Zinnia cells during trans-differentiation. Application of the caspase inhibitors Z-Asp-CH2-DCB, Ac-YVAD-CMK and Ac-DEVD-CHO affected the kinetics of formation and the dimensions of the TEs resulting in a significant delay of TE formation, production of larger TEs and in elimination of the 'two-wave' pattern of TE production. DNA breakdown and appearance of TUNEL-positive nuclei was observed in xylogenic cultures and this was suppressed in the presence of caspase inhibitors. CONCLUSIONS: To the best of our knowledge this is the first report showing that caspase inhibitors can modulate the process of trans-differentiation in Zinnia xylogenic cell cultures. As caspase inhibitors are closely associated with cell death inhibition in a variety of plant systems, this suggests that the altered TE formation results from suppression of PCD. The findings presented here are a first step towards the use of appropriate PCD signalling modulators or related molecular genetic strategies to improve the hydraulic properties of xylem vessels in favour of the quality and shelf life of plants or plant parts
Differential effects of temperature on stem length and xylem vessel length distribution in Zinnia elegans
Twumasi, P. ; Schel, J.H.N. ; Ieperen, W. van - \ 2009
Journal of Horticultural Science and Biotechnology 84 (2009)5. - ISSN 1462-0316 - p. 531 - 535.
tropical lianas - woody-plants - chrysanthemum - dimensions - dif
Water transport in vascular plants depends on the hydraulic conductance of the xylem system, which is dependent on the anatomical properties, number, diameter, and length of the xylem vessels. The ability to transport water through their stems influences not only the growth of many horticultural crops, but also the post-harvest quality of cut flowers. In this study, we investigated the effects of different average daily temperatures (ADT) and the difference between day-time (DT) and night-time (NT) temperature (DIF) on stem size, the length of xylem vessels within the stem, and the length of individual vessel elements within a vessel, in Zinnia elegans. Two Z. elegans cultivars, ‘Envy’ and ‘Purple Prince’, were grown in climate chambers under all nine combinations of three DT and three NT temperatures (viz. 17ºC, 21ºC, or 25ºC). An increase in ADT was positively correlated with the lengths of the stems, internodes, and xylem vessels in both cultivars. However, the lengths of the xylem vessels were influenced more strongly than the lengths of the stems. Increasing the ADT from 17ºC to 25ºC increased stem lengths by approx. 15%, but more than doubled the lengths of the xylem vessels. The increase in xylem vessel lengths was only partly (<10%) due to an increase in the lengths of individual vessel members, which implies that temperature (ADT) had a greater influence on the number of fused vessel elements per xylem vessel. A negative DIF (i.e., lower DT than NT temperatures) decreased stem lengths and a positive DIF increased stem lengths. DIF had no effect on xylem vessel length, probably because, other than in stem length, xylem vessel length was positively correlated with NT temperature.
Establishing in vitro Zinnia elegans cell suspension culture with high tracheary elements differentiation
Twumasi, P. ; Schel, J.H.N. ; Ieperen, W. van; Woltering, E.J. ; Emons, A.M.C. - \ 2009
Cell Biology International 33 (2009)4. - ISSN 1065-6995 - p. 524 - 533.
cellulose synthesis - death - mesophyll - lignification - xylogenesis - involvement - apoptosis - xylem
The Zinnia elegans mesophyll cell culture is a useful system for xylogenesis studies. The system is associated with highly synchronous tracheary element (TE) differentiation, making it more suitable for molecular studies requiring larger amounts of molecular isolates, such as mRNA and proteins and for studying cellulose synthesis. There is, however, the problem of non-uniformity and significant variations in the yields of TEs (%TE). One possible cause for this variability in the %TE could be the lack of a standardized experimental protocol in various research laboratories for establishing the Zinnia culture. Mesophyll cells isolated from the first true leaves of Z. elegans var Envy seedlings of approximately 14 days old were cultured in vitro and differentiated into TEs. The xylogenic culture medium was supplied with 1 mg/l each of benzylaminopurine (BA) and ¿-naphthalene acetic acid (NAA). Application of this improved culture method resulted in stable and reproducible amounts of TE as high as 76% in the Zinnia culture. The increase was mainly due to conditioning of the mesophyll cell culture and adjustments of the phytohormonal balance in the cultures. Also, certain biochemical and cytological methods have been shown to reliably monitor progress of TE differentiation. We conclude that, with the adoption of current improvement in the xylogenic Z. elegans culture, higher amounts of tracheary elements can be produced. This successful outcome raises the potential of the Zinnia system as a suitable model for cellulose and xylogenesis research.
AtSERK1 expression precedes and coincides with early somatic embryogenesis in Arabidopsis thaliana
Salaj, J. ; Recklinghausen, I.R. von; Hecht, V. ; Vries, S.C. de; Schel, J.H.N. ; Lammeren, A.A.M. van - \ 2008
Plant Physiology and Biochemistry 46 (2008)7. - ISSN 0981-9428 - p. 709 - 714.
arabinogalactan proteins - developmental pathway - tissue cultures - callus-cultures - cell - gene - embryos - carrot - plants - methacrylate
The Arabidopsis thaliana primordia timing (pt) mutant was transformed with an AtSERK1::GUS construct. Liquid cultures of this line were used to study the relationship between somatic embryogenesis and the expression of SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (AtSERK1) as a marker for cells competent to form embryos. In order to search for the expression of AtSERK1::GUS during early stages of somatic embryogenesis, histochemical as well as immunochemical approaches were used for the detection of ß-glucuronidase (GUS). Four sites of AtSERK1 expression were found in the embryogenic cultures: in embryogenic callus, where primary somatic embryos developed; in the basal parts of primary somatic embryos; in the outer layers of cotyledons of primary somatic embryos where secondary embryos were formed; and in provascular and vascular strands of developing somatic embryos. The in vitro expression of AtSERK1::GUS coincides with embryogenic development up to the heart-shaped stage. Prior to the expression in embryos, AtSERK1 was expressed in single cells and small cell clusters, indicating that AtSERK1 indeed marks embryogenic competence. Its expression in (pro)
How cellulose synthase density in the plasma membrane may dictate cell wall texture
Emons, A.M.C. ; Akkerman, M. ; Ebskamp, M.J.M. ; Schel, J.H.N. ; Mulder, B. - \ 2007
In: Cellulose: Molecular and Structural Biology / Brown, R.M., Saxena, I.M., Dordrecht : Springer - ISBN 9781402053320 - p. 183 - 198.
Cell differentiation in the pericarp and endosperm of developing maize kernels (Zea mays L.)
Lammeren, A.A.M. van; Kieft, H. ; Schel, J.H.N. - \ 2006
In: Embryology of flowering plants: terminology and concepts. Volume 2: Seed / Batygina, T.B., Enfield, NH, USA : Science Publishers - ISBN 1578082633 - p. 131 - 139.
The patterning of cellulose synthases in the plasma membrane
Akkerman, M. ; Schel, J.H.N. ; Emons, A.M.C. - \ 2005
In: Abstracts Annual Dutch Meeting on Molecular and Cellular Biophysics, 10 and 11 October 2005, Lunteren, The Netherlands - p. 47 - 47.
Topdrukte in de plantencel
Schel, J.H.N. ; Aelst, A.C. van; Simons, Th. ; Lever-De Vries, C. - \ 2005
NVOX Tijdschrift voor Natuurwetenschap op School 30 (2005)8. - ISSN 0929-757X - p. 435 - 437.
Effects of water stress during growth of xylem anatomy, xylem functioning and vase life in three Zinnia elegans cultivars
Twumasi, P. ; Ieperen, W. van; Woltering, E.J. ; Emons, A.M.C. ; Schel, J.H.N. ; Meeteren, U. van; Marwijk, D. van - \ 2005
Acta Horticulturae 669 (2005). - ISSN 0567-7572 - p. 303 - 312.
In cut flowers, hydraulic properties and dimensions of xylem vessels in the stem directly influence vase-life and thus post-harvest quality. Xylem hydraulic conductance as well as recovery from air embolisms at the start of vase life strongly depends on number, diameter and length of xylem vessels in the base of the cut flower stems. In this research we employed different water availability levels (high and low water content) in the growing medium of Zinnia elegans plants of three cultivars ('Envy', 'Purple Prince' and 'Scarlet Flame') to modify xylem anatomy and post-harvest xylem functioning and vase life of cut flowers from these plants. Vase-life was longer among fresh-cut Zinnia flowers in all three cultivars grown under low water content in the root medium. Zinnia flowers of all cultivars grown at high water content were not able to sufficiently restore water uptake at the start of their vase life. Shoot hydraulic conductivity was lower in water-stressed plants but it was not different among the three Zinnia cultivars within the same treatment. Anatomical analysis showed smaller xylem vessel diameters but no differences in xylem number and length, with the exception that in cultivar Purple Prince vessels were longer in well-watered plants. We conclude from these results that within these three Zinnia elegans cultivars water stress conditions in the root environment significantly affected xylem anatomy and functioning which correlates well with a longer vase life. Differences in xylem properties between the three cultivars due to pre-harvest watering treatments were limited
Effects of water stress on xylem anatomy, xylem functioning and vase life during growth of two zinnia elegans cv's
Twumasi, P. ; Ieperen, W. van; Kooten, O. van; Emons, A.M.C. ; Schel, J.H.N. ; Woltering, E.J. ; Ernst, J. - \ 2004
Stop behavior of Golgi bodies in the cortical cytoplasm of Arabidopsis root epidermal cells; a comparison between growing and non-growing cells
Akkerman, M. ; Mulder, B. ; Emons, A.M.C. ; Schel, J.H.N. - \ 2004
In: ALW/FOM/VvBBMT Meeting on Molecular and Cellular Biophysics, september 2004 Lunteren, the Netherlands : - p. 43 - 43.
How the geometrical model for plant cell wall formation enables the production of a random texture
Mulder, B. ; Schel, J.H.N. ; Emons, A.M.C. - \ 2004
Cellulose 11 (2004)3-4. - ISSN 0969-0239 - p. 395 - 401.
arabidopsis root hairs - microfibril deposition - winding threads - vicia-sativa - actin - architecture - growth - tip - morphogenesis - disruption
Cellulose synthase (CESA) molecules are the building blocks and catalytic centers of the CESA complex. The study of mutants in Arabidopsis has led to insight into the structure of these nanomachines. Inside the plasma membrane, the CESA molecules are arranged in complexes, which, apart from the CESA molecules proper, contain other, mostly unidentified, proteins. We developed a theory in which CESA density, together with distance between cellulose microfibrils (CMFs) being deposited and cell geometry, determines wall texture. We have shown earlier how this theory is able to explain the production of axial, helical, helicoid and crossed-polylamellate textures. In the present article we extend this theory to random wall textures.
Cellulose microfibrils in root hairs of Arabidopsis: A TEM study
Franssen-Verheijen, M.A.W. ; Aelst, A.C. van; Emons, A.M.C. ; Schel, J.H.N. - \ 2003
In: Proceedings NVvM Meeting, Papendal, December 2003, The Netherlands - p. 110 - 110.
Effect of water stress during growth on xylem anatomy in three Zinnia elegans cv's
Twumasi, P. ; Ieperen, W. van; Woltering, E.J. ; Emons, A.M.C. ; Schel, J.H.N. ; Snel, J.F.H. ; Meeteren, U. van; Marwijk, D. van - \ 2003
The stop behavior of Golgi bodies in plant cells. A comparison between growing cells and full grown cells
Akkerman, M. ; Mulder, B. ; Emons, A.M.C. ; Schel, J.H.N. - \ 2003
Stop behaviour of Golgi bodies as a marker for insertion of cellulose synthases into the plasma membrane
Akkerman, M. ; Mulder, B. ; Emons, A.M.C. ; Schel, J.H.N. - \ 2003
In: ALW/FOM/VvBBMT-Meeting on molecular and cellular biophysics, 29 and 30 September 2003, De Werelt, Lunteren, The Netherlands - p. 39 - 39.
Cellulose microfibrils in root hairs of Arabidopsis - a TEM study
Franssen-Verheijen, M.A.W. ; Aelst, A.C. van; Emons, A.M.C. ; Schel, J.H.N. - \ 2003
In: Abstracts of the 7th International Botanical Microscopy Meeting Plant Cell Biology Saturday 12 - Thursday 17 April 2003 Lisbon : Royal Microscopical Society - p. 50 - 50.
Delivery of cellulose synthases to the plasma membrane
Akkerman, M. ; Emons, A.M.C. ; Schel, J.H.N. - \ 2003
In: Abstracts of the 7th International Botanical Microscopy Meeting Plant Cell Biology Saturday 12 - Thursday 17 April 2003 Lisbon : Royal Microscopical Society - p. 43 - 43.
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