Plants cannot run away from stress! Whenever it get's cold, too hot, or if there is no water (drought), they have to deal with the conditions themselves. Luckily, millions of years of evolution, plants have evolved various smart strategies to quickly respond to stress and deal with the specific changes in its environment. The main interest of Plant Cell Biology within the Green Life Science Cluster, is to unravel the molecular mechanisms by which plant cells perceive environmental stress, how these signals are intracellularly transduced, and how they are converted into appropriate responses that allow plants to deal with the particular stress. We are specifically interested in the early signalling pathways that report temperature stress (cold, heat), water stress (drought, salinity, hypo-osmotic stress), and microbes (pathogens, symbionts), in particular, in the role of membranes and the participation of certain lipids in the signal transduction process.
Research at Plant Cell Biology is primarily focussed on phospholipid signalling during Plant Stress & Development. Especially, the lipid second messengers PA, DGPP and polyphosphoinositides (PPIs), like PIP and PIP2 have our interest. Such molecules are present at relatively low concentrations in membranes and most are rountinely missed by common lipidomic analyses. Nonetheless, they can be easily monitored by labelling cells or tissues with radioactive 32Pi in vivo, because the turnover of signalling lipids is much faster than of structural phospholipids, and because they are synthesised via kinases that use ATP, which is one of the first compounds to be labelled. Key players in PA and PPI metabolism and signalling are depicted in the scheme above, involving PLC-and PLD signalling and a variety of lipid- and inositolphosphate kinases (e.g. DGK, PI4K, PIP5K, and IPKs). Note that PA can be generated through both PLC- and PLD pathways, which occurs at different cellular- and subcellular locations, and in response to different stimuli, resulting in different outputs.
Another important signalling route concerns PPIs that are phosphorylated at the D3-position of the inositol ring. PI is then phosphorylated by a specific PI3K (called VPS34) to form the PIP isomer, PI3P, which plays crucial roles in endomembrane trafficking to the vacuole and in autophagy. PI3P can be further phosphorylated by PI3P 5-kinases (FAB1-4) to form the lipid second messenger, PI(3,5)P2, which is also involved in membrane trafficking and is activated during osmotic stress.
These signalling lipids are routinely analysed using in vivo 32Pi-labelling. Cells-, seedlings- or tissues (e.g. leaf discs) can be used with labelling times varying from minutes to hrs or O/N, depending on the type of experiment (e.g. turnover vs mass levels). To monitor PLD activity in vivo, transphosphatidylation assays are conducted, which includes the addition of a primary alcohol (see 'All Publications' ref 9, 18). An example with the green alga Chlamydomonas is shown, where cells were prelabelled for 4 hrs and then stimulated for 5 min in the presence or absence of a low concentration of a primary alcohol (methanol, ethanol, propanol, or butanol) that cells don't mind. Extracted lipids were then chromatographed using a TLC solvent that separates phosphatidylalcohols from the rest of the phospholipids (panel a). PLD catalyses the transphosphatidylation, so the production of 32P-phosphatidylalcohol is a relative measure for in vivo PLD activity. PhosphoImaging can be used for their visualization and quantification. We found that PLD is activated by various environmental stresses, including, heat-, drought-, and salt stress, and also by certain pathogens. The genome of Arabidopsis encodes for 12 PLD genes, while rice even rice 17, and this is in huge contrast to e.g. humans, which only contain two PLDs. We are investigating which PLD does what.
Similarly, the activation of PLC, and PI-, PIP-, DAG- and PA kinases can be monitored. For this, lipids are chromatographed with another TLC solvent (panel b). As example, the timing and duration of the activation was performed using a time-course experiment. Note the PLC hydrolysis of PIP2 (PtdInsP2) within 15 sec to produce InsP3 and DAG, with the latter being converted into PA by DAG kinase (DGK). PI- and PIP-kinase are also activated to replenish the PIP- and PIP2 levels. Since PLC is down regulated before the lipid kinases are, a slight overshoot in PIP and PIP2 production is witnessed. In the same time frame, PA signalling is being attenuated by converting it into DGPP by PA kinase (PAK). The formation of DGPP starts again a new signal.
Over the years, we discovered that 'flowering plants' contain 30-100 fold lower PIP2 levels than Chlamydomonas or animal cells. This discrepancy has major consequences for the interpretation of plant PLC signalling and what it uses as in vivo substrate (see ref. 70), i.e. PI4P rather than PI(4,5)P2.
Both PLD and DGK can generate PA as second messenger. To distinguish between both pools, a Differential Labelling Protocol was developed. It uses a difference in kinetics by which PA can become radioactive. Relatively short labelling times are required for PADGK while long labelling is needed for PAPLD, This is because DGK requires ATP to make PA, and ATP is one of the first components to become labelled when cells are incubated with 32Pi. In contrast, PLD requires 32P-labelled structural lipids like PE to generate 32P-PA, and this takes hours of metabolic labelling (panel top). Moreover, using the transphosphatidylation assay, one can check how long 32Pi-prelabelling is required before structural phospholipids would generate 32P-PBut, and thus 32P-PAPLD.
The TLC panels (A-D) show what happens in Chlamydomonas cells that were metabolically labelled with 32Pi for the times indicated (min-> hrs), and subsequently treated for 1 min with buffer (control; panel A, B) or a stimulus (in this case 1 µM mastoparan (panel C, D), both in the presence of 0.1 % n-butanol to monitor PLD activity. Extracted lipids were split and either seperated on EtAc TLC (A, C) to separate the PLD-catalyzed PBut, or Alkaline TLC (B, D) to visualize the rest of the phospholipids, including PA and its phosphorylation into DGPP.
The point is that all cells were treated for exactly the same time period (1 min) but that PBut will only became radioactive when its substrate (i.e. PE) became labelled (>40min). The same would hold for the PAPLD. In contrast, PADGK would receive its label from ATP, and since this compound is labelled within sec, a much faster increase in 32P-PA would be witnessed if PLC/DGK was involved. Since PA kinase also uses ATP, a similar response in DGPP can be expected (panel D). Since the specific radioactivity of 32P-ATP decreases over time, the 1-min response decreases concomitantly. The combined assay is a relative qualitative measure and provides evidence for PA coming through eeither DGK- and/or PLD pathways. See details in Arisz et al. , 2009 (Ref 68, 84) and the DGK-specific response to cold stress (ref 80).
To visualize lipid signalling with confocal imaging, we developed various lipid biosensors. These are genetically encoded lipid-binding domains fused to a Fluorescent-Protein (FP), which can be expressed in cell suspensions or whole plants. The first example, was generated in 2006 for PI3P in tobbaco cells and whole Arabidopsis plants. This was followed with PI(4,5)P2 (2007), PI4P (2009), PI(3,5)P2 (2016), DAG (2017) and PA (2023). In 2014, Yvon Jaillais' lab (Lyon) added several colors to PI3P, PIP4 and PI(4,5)P2 markers (ref), and made important new ones for PA and PS. All biosensor lines are publically available.
Using T-DNA insertion KO and OE mutants of the model system Arabidopsis thaliana, the participation of individual PLCs, PLDs, PIP5Ks and DGKs in stress signalling & development is investigated. Arabidopsis contains 9 PLC-, 12 PLD- and 7 DGK genes. In addition, there are 11 PIP5K, 12 PI4K, 1 PI3K, 4 FAB and multiple PA- and PPI phosphatase (e.g. SAC1-9) genes too. For many of them, we have mutants that we are happy to share.
Below, an example of reduced salt tolerance for Arabidopsis PLD mutants is shown. Seeds from wild-type (Col-0, black circles), pldα1 (open squares), pldδ (open triangles) or pldα1/pldδ double (open diamonds) knock-out mutant lines were sown on agar plates and grown vertically in a growth chamber. After 3 days seedlings were transferred to fresh plates supplemented with 0, 75 or 150 mM NaCl. Plates were scanned after 8 days (a) and primary root growth was followed and averaged ± SE during 4 days after transfer (b; n=12-16; a representative experiment is presented). (ref 63)
PPIs play distinct roles in membrane trafficking. This is examplified during cell divison, where PI3P, PI4P and PI(4,5)P2 exhibit distinct patterns when the new plasma membrane and cell wall is formed, seperating the mother cell into two daughter cells, and the respective lipids were followed via our biosensors (green, YFP or red, mRFP for PI4P). The lipophylic dye, FM4-64 (red) was used to stain membranes in general. While PI3P (green) accumulates in vesicles (late endosomes) that surround the cell plate, but is never part of the new plasma membrane (panel C), PI4P and DAG were always on the plasma membrane, right from the start when build (panel B, D). PI(4,5)P2, however, is only present at the leading edges of the plasma membrane following the expanding cell plate (A).
Heat stress induces an array of physiological adjustments that facilitate continued homeostasis and survival during periods of elevated temperatures. We discovered that plants rapidly produce PIP2 within minutes of a sudden temperature increase. Using the PIP2biosensor, we found that the PIP2 is produced at the plasma membrane, nuclear envelope, nucleolus and at punctate cytoplasmic structures ( see below). Increases in steady-state levels of PIP2 occured within several min of temperature increases from ambient levels of 20-25°C to 35°C and above. Similar patterns were observed in heat stressed Arabidopsis seedlings and rice leaves. 32P-Pulse-labelling analyses revealed that the PIP2 response is generated through activation of a PIP5K rather than an inhibition of a lipase or PIP2 phosphatase (see ref 64, 69). Using T-DNA insertion KO mutants we are currenly identifying which of the 11 PIP5Ks is/are involved. The work involves a long-standing collanboration with Dr. Michael Mishkind (NSF).
Interestingly, in response to cold stress, PA is formed as a lipid second messenger (ref 80). Using a novel probe, we are currently aiming to discover novel PA targets than those we identified earlier (ref 41, 43, 45, 54, 56, 59, 79, 81, 95, 101)
Osmotic stress responses not only involves salinity and drought but also hypotonic stress . Using 32Pi-labelling, specific PA and PPI responses have been uncovered (18, 21, 26, 29, 30, 40, 55). For the PPIs, different isomers are involved, which can be analyzed by lipid biosensors but also by HPLC analysis, using a strong anion-exchanger after deacylation, which generates the corresponding GroPIns' isomers (see HPLC profile below).
Lipid biosensor lines are used to find out where lipid signals are generated (55) while KO mutants are used to pinpoint which isoenzymes and genes are involved (63; Zarza et al., 2019, 2020; in prep).
PLC and PLD signalling cascades can individually generate PA, an important eukaryotic lipid second messenger. PLC generates it indirectly via the hydrolysis of PI4P and the subsequent phosphorylation of diacylglycerol (DAG) into PA via DAG kinase (DGK). PLD generates PA directly by hydrolyzing structural pospholipids, such as phosphatidylcholine (PC). Earlier, we have provided evidence for the role of PA in plant defence using elicitor-challenged cell suspensions of tomato, parsley and alfalfa. Currently, we are adressing PA's role genetically using the model system, Arabidopsis thaliana.
Arabidopsis contains 9 PLCs, 7 DGKs and 12 PLDs. To identify the genes involved in plant defence and characterise their individual functions, T-DNA insertion KO or KD lines have been collected of most genes. Plants were then analysed for their disease resistance and sensitivity to virulent- and avirulent strains of the bacterial pathogen Pseudomonas syringae and the natural pathogen Hyaloperonospora parasitica , the causal agent of downy mildew. A DGK gene was found to be required for full resistance against virulent Pseudomonas and H. parasitica, while two PLD genes were found to be involved in the resistance against avirulent Pseudomonas (unpublished)
Work from Dr. Laura Zonia focussed on one of the fastest growing cells of this planet: pollen tubes. The goal of the research was to identify the key cascades that control pollen tube growth and to understand how these networks link to the biomechanics that drive cell elongation. Several key cascades were identified, including actin cytoskeleton, ion fluxes and various phospholipid signals. Other workers have identified other cascades important for pollen tube growth, including GTPases, protein kinases, and processes involved in cell wall synthesis. Common themes emerging across these information cascades are osmoregulation and cell volume status. Further work confirmed that many of these networks indeed converge at this point, where we revealed that transcellular hydrodynamic flux drives the growth of a pollen tube and modulates rates of exocytosis and endocytosis.
Time-lapse images of tobacco pollen tubes double-labelled with FM 1-43 (green) and FM 4-64 (red) to identify sites of endocytosis and exocytosis and visualize membrane trafficking patterns. The first 3 images are from a pollen tube undergoing normal growth. The next 3 images are from a pollen tube undergoing hypertonic stress, which stimulates endocytic membrane retrieval at the apex and inhibits exocytosis. The last 2 images are from a pollen tube undergoing hypotonic stress, which stimulates exocytosis and growth, and attenuates endocytosis. Together with previous work (Zonia and Munnik, 2007), these data reveal that transcellular hydrodynamic flux is a key integrator of pollen tube growth, providing a motive force for cell elongation and regulating the rates of membrane insertion( exocytosis ) and retrieval (endocytosis). See refs 40, 49, 51, 53,57,60, 66.
Accumulating evidence suggests that PA plays a pivotal role in the plant's response to environmental signals. Besides PLD, PA can also be generated by DGK. To establish which metabolic route is activated, a differential 32P-labelling protocol can be used (see above). Based on this and on reverse-genetic approaches, DGK has taken center stage, next to PLD, as generator of PA in biotic- and abiotic-stress responses. The substrate, DAG is generally thought to be derived from PLC. The model plant system Arabidopsis thaliana contains 7 DGKs, two of which, AtDGK1 and AtDGK2, resemble mammalian DGKε, encoding a conserved kinase domain, a transmembrane domain and two C1 domains. The other DGKs have a simpler structure, lacking C1 domains, which appear absent in animals. Several protein targets that bind PA have been discovered (Testerink and Munnik, 2011). Whether PA comes from PLD or DGK often remains to be elucidated though. For cold stress, this is know, triggering PA via DGK within minutes (ref 107). Freezing (and thus wounding) involves multiple PLD (ref 63, 65).
In comparison to mammals (which only two possess PLD) or yeast (one), plants contain multiple PLD genes. The genome of Arabidopsis thaliana counts 12 PLD family members and this diversity has been found in assorted higher plant species. Eukaryotic PLD enzymes are characterized by two highly conserved carboxy-terminal (C-terminal) catalytic domains and an amino-terminal (N-terminal) lipid-binding region (see Figure). The two catalytic HxKxxxxD (HKD) motifs interact and are essential for the lipase activity of rat PLD1.
The plant PLD family can be divided into two sub-families, based on their N-terminal lipid-binding domains (see below). In Arabidopsis, two of the 12 PLDs contain a Phox homology- (PX) and pleckstrin homology (PH) domain, whereas the remaining 10 PLDs contain a C2 domain. PX and PH domains have been shown to mediate protein-membrane targeting and are closely linked to PI3P signaling. C2 domains also mediate the localization of soluble proteins to membranes by binding lipids in a Ca2+-dependent manner. The plant-PLD family can be further subdivided into six classes, based on sequence homology and in vitro activity. As such, Arabidopsis contains three α-, two β-, three γ-, one δ-, one ε- and two ζ-class PLD isoforms; the latter contain the PX and PH domains and share homology with the yeast and mammalian PLDs.
PI-PLCs have been classified into six subfamilies, β, γ, δ, ε, η and ζ, based on domain structure and organization, (Figure; Munnik & Testerink, 2009). Mammalian cells contain all six isoforms (13 in total) whereas plants only exhibit one, i.e PLCζ-like, which is the class that lacks the Pleckstrin Homology (PH) domain present in all other PI-PLCs. In mammalian cells, PLCζ is specifically expressed in sperm cells.
PLCζ represents the most simple PI-PLC isoform, only consisting of the catalytic X- and Y-domain, an EF-hand domain and a C2 lipid-binding domain. Other subfamilies contain, besides the beforementioned domains, conserved sequences that allow them to be regulated by e.g. heterotrimeric G-proteins (PLCβ), tyrosine kinases (PLCγ), or Ras (PLCε). How PLCδ, -η and -ζ isoforms are regulated is unclear but may involve Ca2+. How plant PLCs are regulated is still completely unknown. Using KO mutants we found that various PLCs are involved in lateral root formation and are predominantly expressed in or near the phloem. Overexpression of PLC leads to improved drought tolerance (Van Wijk et al., 2018; Zhang et al., 2018a,b).
Abbreviations: EF, EF-hand domain; PH, Pleckstrin homology domain; RA, Ras-binding domain; RasGEF, guanine-nucleotide-exchange factor for Ras; SH, Src homology domain; X and Y, catalytic domain.
Lipid Signaling in Plants . Series: Plant Cell Monographs,
Vol. 16 , Munnik, T. (Ed.) 2010, 330 p. 49 illus., 7 in
color., Hardcover. ISBN: 978-3-642-03872-3. Springer Verlag, Heidelberg,
Plant Lipid Signaling Protocols. Munnik T . and Heilmann I. ( Eds.) 2013. Series: Methods in Molecular Biology 1009, Humana Press, NJ, USA. 305 p.
1. De Nobel JG, Munnik T, Priem J, van den Ende H, Klis FM. (1990) Conditions for increased cell wall porosity in Yeast. Proceedings 3rdNetherlands Biotechnology Congress, Amsterdam, April 3-4, 1990. H Breteler, RF Beudeker and KChAM Luyben (Eds), pp. 300-304.
2. De Vrije T. & Munnik T. (1998) Signal Transduction pathways and senescence. In: The Post-Harvest Treatment of Fruit and Vegetables - Current Status and Future prospects. Eds. Woltering EJ, Gorris LG, Jongen WMF, McKenna B, Höhn E, Bertolini P, Woolfe ML, de Jager A, Ahvenainen R, Artes Calero F, Luxembourg, European Communities, pp 329-338 (ISBN 92-828-2003-3).
3. Testerink C. & Munnik T. (2004) Plant response to stress: phosphatidic acid as a second messenger. In Encyclopedia of Plant & Crop Science(RM Goodman, ed.), Marcel Dekker Inc, New York, 995-998.
4. De Wit PJGM, Brandwagt BF, van den Burg HA, Gabriëls SHEJ, van der Hoorn RAL, de Jong CF, van ‘t Klooster JW,de Kock MJD, Kruijt M, Luderer, R, Munnik T, Stulemeijer IJE, Thomma BPHJ, Vervoort JJM, Westerink N, Joosten MHAJ. (2004) Molecular basis of plant response to microbial invasion.In: Biology of Plant-Microbe Interactions, Vol. 4, Tikhonovich I, Lugtenberg B, Provorov N (Eds.), International Society for Molecular Plant-Microbe Interactions, St. Paul, Minnesota, USA, pp. 203-207.
5. Zonia L. & Munnik T. (2006) Cracking the green paradigm: Functional coding of phosphoinositide signals in plant stressresponses. In: Subcellular Biochemistry, Vol. 39:Biology of Inositols and Phosphoinositides (Majunder AL and Biswas BB, eds.), Kluwer/Plenum Publishers, London, UK, pp207-237.
6. Lee Y, Munnik T, Lee Y (2010) Plant Phosphatidylinositol 3-kinase. In Lipid Signaling in Plants. Series: Plant Cell Monographs, Vol. 16, Munnik, T. (Ed.), Springer-Verlag, Heidelberg, Germany, pp95-106.
7. Arisz SA and Munnik T. (2010) Diacylglycerol kinase. InLipid Signaling in Plants. Series: Plant Cell Monographs, Vol. 16, Munnik, T. (Ed.), Springer-Verlag, Heidelberg, Germany, pp107-114.
8. Vermeer JEM and Munnik T. (2010) Imaging lipids in living plants. In: Lipid Signaling in Plants. Series: Plant Cell Monographs, Vol. 16, Munnik T.(Ed.), Springer-Verlag, Heidelberg, Germany, pp185-199.
9. Munnik T. (2014) PI-PLC: Phosphoinositide-phospholipase C in plant signaling. In: Phospholipases in Plant Signaling. Wang X. (Ed.), Signaling and Communication in Plants 20, Springer-Verlag, Berlin Heidelberg. pp 27-54.
Plant Stress Signalling - Signal transduction - Phospholipid signalling - Membrane trafficking - Abiotic Stress (cold, heat, drought, salt) - Biotic Stress (plant-pathogen) - Arabidopsis Development - Molecular Heaters
Cell Biology, Biochemistry, Molecular Biology, Plant Physiology
• British Council Fellowship (1994)
• EMBO short-term Fellowship (1997)
• PULS Fellowship (1998-2001)
• KNAW (Dutch Royal Society of Sciences) Fellowship (2000-2005)
• VIDI fellowship for innovative research (2005-2010)
• ECHO grant (2007)
• VPP grant (2011)
• NPST grant (2012)
• NWO-DBT grant (2015-2020)
• ECHO grant (2018-2021)
• IXA grant (2018)
• EU-FET grant (2019-2024)
• ENW-Klein (2021-2025)
Publications: (see All Publications)
• Number of publications in international refereed scientific journals according to WoS: 133
• Contributions to books:
- 2 books (Ed. 2010; Ed. 2013, both Springer);
- 7 chapters
• Number of citations according to WoS: >11.200; average citations: 82; H-index: 59
• Lecturer at various International Advanced Courses (e.g. ICRO; FEBS, EPS, UNMP, TWAS)
• Coordinator and teacher of various BSc, MSc and PhD courses (molecular cell biology, biochemistry, cellular physiology, plant-abiotic stress)
• >160 Invited seminars at (inter)national universities, conferences and symposia, world wide (see below).
• Organiser of SILS seminars, University of Amsterdam (2000-2005)
• Organiser of Plant Science Meetings (PSM) & Green Life Science (GLS) seminars (2017-2019) , SILS, University of Amsterdam
• Conference chair at various national- and international conferences (>10)
• Organiser & chair of Gordon Research Conference (GRC) Salt and Water Stress 2012, Hong Kong, China.
• Co-organiser of the 15th World Conference of Parasitic Plants (WCPP2019), Amsterdam, The Netherlands.
• Co-organizer 'Chemical Ecology Amsterdam' Symposium (2018), Amsterdam, The Netherlands.
• Organiser of the 10th ESPL, European Symposium on Plant Lipids (2023), Amsterdam, The Netherlands.
Currently, no vacancies
(e.g. FEBS, EMBO, Marie Curie, etc) - please contact: t.munnik @ uva.nl
Phosphatidic acid (PA) and polyphosphoinositides (PPIs) are minor phospholipids in biological membranes that function as cellular signalling molecules at low concentrations. Their turnover is much faster than of structural phospholipids and levels quickly change in response to biotic- (pathogens) and abiotic- (salt, cold, heat, drought) stress. How this is activated, regulated and where this occurs in cells (e.g. plasma membrane, ER, Golgi) or tissues (e.g. root, stem, stomata) has our particular interest. The model plant Arabidopsis thaliana contains various lipid kinases, phosphatases and phospholipases, and by using knock-out mutants, overexpression lines, and FP fusions, we are unraveling their role in plant stress signalling and development. Personal felowships or students can be involved in any of these projects.
Teun Munnik (PI)
Ing. Ringo van Wijk (Lab manager)
Dr. Steven Arisz (Post-doc)
Ms. Hui Sheng (PhD student)
Ms. Emy Latul (PhD student)
Michael Mishkind (RIP)
Laura Zonia (Washington University in St. Louis, MO, USA)
Aleksandra Haduch (PhD student, Poland)
Wendy Roels (Naktuinbouw)
Dörte Klaus (PD, Toulouse, F)
Christiane Unger (MSc, Halle, Germany)
Alan Musgrave (UvA, retired)
Ana Laxalt (PI, Mar del Plata, Argentina)
Bas ter Riet (Enza Zaden, Enkhuizen, NL)
Harold Meijer (WUR, Wageningen, NL)
Christa Testerink (Prof. Plant Physiology, WUR)
Wessel van Leeuwen (Hazera Seeds, NL)
Rafa Tobeña (Madrid, Spain)
Gert-Jan de Boer (Enza Zaden, Enkhuizen, NL)
John van Himbergen (VROM)
Diewertje van der Does (UU, Utrecht, NL)
Saskia van Wees (UU, Utrecht, NL)
Fabio Formiggini (Italy)
Gaby Gonorazky (Uni of Mar del Plata, Argentina)
Martine den Hartog (Covidien, Amsterdam)
Arnold van der Luit (Oncodesign, France)
Bastiaan Bargmann (CA, USA)
Bas van Schooten (NWO)
Essam Darwish (Uni. Cairo, Egypt)
Joop Vermeer (Prof. Plant Cell Biology, Uni of Neufchatel, Switzerland)
Muhammad Shahbaz (Assoc. Prof., Dept. of Botany, University of Agriculture, Faisalabad, Pakistan)
Qianqian Zhang (Nikon, Shanghai, China)
Jessica Meyer (technician WUR)
Nazish Annum (Agricultural Biotechnogy Division, National Institute for Biotechnology and Genetic Enginering, Faisalabad, Pakistan)
Ruud Korver (researcher, ENZA)
Mhyrte Praat (PhD student Utrecht University)
Floris Stevens (PhD student GLS-SILS)
Dr. Leonardo Hinojosa (PhD student IBED)
Dr. Femke de Jong (jounalist)
Max van Hooren
Xandra Schrama (technician IBED)
Martine den Hartog
Julian C. Verdonk
Steven A. Arisz
Bas ter Riet
Diewertje van der Does
Jacco van Rheenen
Tessa Nauta (MSc student)
Maarten Reitsema (MSc student)
Jiorgos Kourelis (MSc student)
Carlos Jr. Rubio 'Chucho' (HBO student)
Mark aan 't Goor (MSc student)
Matthew Lefebvre (MSc student)
Ruy Kortbeek (MSc student)
Mart Lamers (BSc student)
Max Stam (MSc student)
Kinwai Fung (MSc student Leiden)
Milan Plasmeijer (MSc student)
Martijn van Ophem (MSc student)
Floris Stevens (MSc student)
Rui Alvez (Erasmus student)
Babette Vlieger (BSc student)
Ludo Cialdella (BSc student)
Jack Dickenson (MSc student)
Eveline Bosman (BSc student)
Valerie de Ridder (BSc student)
Emy Latul (MSc student)
Willard Bout (MSc student)
Sjors Huizinga (MSc student)
Pauline Caris (MSc student)
Tijmen Blokzijl (MSc student)
Divya Jagger (MSc student)
Eva van Doore (MSc)
Sjors Huizinga (MSc)
Inam Barakat (BSc & MSc)
Max Pijfers (MSc student)
Ilse Bakker (MSc student)
Dr. Michael Mishkind (RIP)
Dr. Ana Laxalt (Mar del Plata, Argentina)
Dr. Joachim Goedhart (WU, Wageningen)
Dr. Dorus Gadella (WU, Wageningen)
Dr. Bas Tomassen (Erasmus Rotterdam, NL)
Dr. Katie Anne Wilkins (Birmingham, UK)
Dr. Anne Sophie Leprince (Paris, France)
Dr. Noam Reznik (Tel Aviv, Israel)
Dr. Magdalena Wierzchowiecka (Poland)
MSc. Özgecan Tanyolaç (Izmir, Turkey)
MSc. Maria Alejandra Schlöffel (University of Tübingen, Germany)
Dr. Bojan Gujas (ETH, Zürich, Switzerland)
Dr. Necla Pehlivan (Turkey)
Dr. Theodora Farmaki, (Thessaloniki, Greece)
Dr. Wojciech Rymaszewski (Warsaw, Poland)
Dr. Hui-fen Kuo (Academia Sinica, Taiwan)
Dr. Kelly Stecker (University of Wisconsin, USA)
Dr. Muhammad Jamil (WUR)
MSc Madiha Butt (Faisalabad, Pakistan)
Dr. Tomoko Hirano (Kyoto Prefectural University, Japan)
Dr. Jyothilakshmi Vadassery (Max Planck, Germany)
MSc. Dominik Novák (Palacky University, Olomouc, Czech Republic)
MSc. Nazish Annum (University of Faisalabad, Pakistan)
Dr. Aansa Rukya Saleem (Bahria University, Islamabad, Pakistan)
Dr. Ania Kasprowicz-Maluśki (Uniwersytetu Poznańskiego, Poznań, Poland)
Dorus Gadella (SILS, UvA, NL)
Nullin Divecha (Manchester, UK)
Takashi Aoyama (Kyoto University, Japan)
Erik Nielsen (Michigan, US)
Ana Laxalt (University of Mar del Plata, Argentina)
Charles Brearley (Norwich, UK)
Gertjan Kramer (SILS-MS, UvA, NL)
Harro Bouwmeester (GLS-PHB, UvA, NL)
Ingo Heilmann (Halle, Germany)
Robin Irvine (Cambridge, UK, retired)
Laura de la Canal (Mar del Plata, Argentina)
Nick Ktistakis (Cambridge, UK)
Ralf Oelmüller (Jena, Germany)
Jack Vossen (WUR, Wageningen, NL)
Gerard van der Linden (WUR, Wageningen, NL)
Dierk Scheel (Halle, Germany)
Dorothea Bartels (Bonn, Germany)
George Carman (Rutgers, NJ, US)
Laci Bögre (London, UK)
Claudia Jonak (Vienna, Austria)
Susanne Hoffmann-Benning (Michigan, US)
Pavla Binarova (Prague, Czech Republic)
Jörg Kudla (Münster, Germany)
Silke Robatzek (Münich, Germany)
Mariusz Pietruszka (University of Silesia, Poland)
Antonio Fernandez Tiburcio (Barcelona, Spain)
Noni Franklin-Tong (University of Birmingham, UK)
Edgar Kooijman (Kent, USA)
Aviah Zilberstein (Tel Aviv, Israel)
İsmail Türkan (Izmir, Turkey)
Pia Harryson (Stockholm, Sweden)
Tzyy-Jen Chiou (Academia Sinica, Taiwan)
Libo Shan (Texas A&M University, US)
Ping He (Texas A&M University, US)
Glenda Gillaspy (Virginia Tech, US)
Yee-yung Charng (Academia Sinica, Taiwan)
Taijoon Chung (Pusan National University, Republic of Korea)
Jenny Russinova (VIB, Ghent University, Belgium)
Gabriel Schaaf (University of Bonn, Germany)
Luis Lopez-Molina (University of Geneva, Switzerland)
Antia Rodriguez-Villalon (ETH, Zürich, Sitzerland)
Christian S. Hardtke (Lausanne, Sitzerland)
Niko Geldner (Uni of Lausanne, Switzerland)
Joop Vermeer (Uni of Neuchatelle, Switzerland)
Wybren Jan Buma (HIMS, Molecular photonics UvA)
Jan van Maarseveen (HIMS, Organisc chemistry, UvA)
Jiri Friml (IST Austria)
Dominique van der Straeten (Ghent, Belgium)