People

PI/CI

Dr Staffan Persson

moiStaffan Persson completed his PhD in Dec, 2003, which was a joint degree between Lund University (Sweden) and North Carolina State University (US). He then pursued a postdoc at the Carnegie Institution of Washington at Stanford University 2004-2007. Staffan was appointed as a Max-Planck Group Leader at the MPI for Molecular Plant Physiology in Potsdam in 2008, where he stayed until 2014. Since Jan 2015 Staffan is a R@MAP Professor at the School of BioSciences at University of Melbourne, and recently became an ARC Future Fellow (level 3). The research in his group aims at understanding how plants are producing cellulose, which is the most abundant biopolymer on Earth and that is a raw material for many applications in our society.

Email: Staffan.persson@unimelb.edu.au

 

Postdocs

Dr Heather McFarlane

H McFarlaneMy Research: In order to grow, plants must carefully monitor and coordinate cell wall synthesis with development; plants must also sense environmental signals and modulate growth in response. This raises two questions that intrigue me: 1) how do plants sense the status of their cell walls? and 2) how do plants remodel their cell walls in response to these signals? I am particularly interested in the Golgi apparatus and trans-Golgi network as sites where both the secretion of cellulose synthesis enzymes and the synthesis of matrix polysaccharides can be controlled. I combine live cell imaging, electron microscopy, biochemistry, and genetics to elucidate the molecular mechanisms of plant cell wall signalling in order to understand how plants maintain and adjust their growth growth under changing conditions.

About Me: I earned my PhD in 2013 at the University of British Columbia in Vancouver, Canada. At UBC, I worked with with Prof. Lacey Samuels studying the synthesis and export of lipids that form the protective plant cuticle. After this, I took up an EMBO Long-Term Fellowship with Prof. Persson at the Max Planck Institute for Molecular Plant Physiology in Potsdam, Germany. I relocated to the University of Melbourne in 2015 to continue working with Prof. Persson as an NSERC Postdoctoral Fellow and a University of Melbourne McKenzie Fellow. I am currently an ARC DECRA fellow.

Email: heather.mcfarlane@unimelb.edu.au

Selected References:

McFarlane, H.E., Döring, A., and Persson, S. 2014. The cell biology of cellulose synthesis. Annual Review of Plant Biology 65: 69-94.

McFarlane, H.E., Watanabe, Y., Yang, W., Huang, Y., Ohlrogge, J., and Samuels, A.L. 2014. Golgi and TGN-mediated vesicle trafficking is required for wax secretion from epidermal cells. Plant Physiology 164: 1250-1260.

Gendre, D.*, McFarlane, H.E.*, Johnson, E., Mouille, G., Sjödin, A., Oh, J., Levesque-Tremblay, G., Watanabe, Y., Samuels, A.L., and Bhalerao, R.P. 2013. Trans-Golgi network localized ECHIDNA/Ypt interacting protein complex is required for the secretion of cell wall polysaccharides in Arabidopsis. The Plant Cell 25: 2633-2646 * DG & HEM contributed equally.

(read more on Google scholar: https://scholar.google.ca/citations?hl=en&user=kXiC3xgAAAAJ&view_op=list_works)

 

Dr Marc Somssich

My research: Coming from the field of developmental biology, I am interested in studying how developmental and environmental cues are translated into changes in the composition of the plant cell wall. While all plant cell walls are primarily made up of different polysaccharides such as cellulose, hemicellulose (e.g. xyloglucan) and pectins, the exact composition of these sugars in the walls of different cells is variable and depends on the developmental stage the cell is in, its specialization and the environment. By analyzing the polysaccharide composition of different cell types, and studying the role of different cell wall modifying proteins, such as Xyloglucan endoTransglucosylases/Hydrolases (XTHs) or EXPANSINS, in these cells and in response to different stimuli, it should be possible to investigate how these differences in cell wall composition are triggered and maintained.

About me: I studied Biology at Heinrich Heine University in Düsseldorf, Germany, where I joined the Lab for Developmental Genetics of Professor Rüdiger Simon in 2007. During his time in the lab I studied the role of the different CLAVATA receptors in plant stem cell maintenance and helped to establish new fluorescence imaging-based protein interaction techniques. For this work I received my Diplom in 2008 and subsequently a Doctoral degree in 2014. I joined the Persson Lab at the University of Melbourne in early 2016, and am a DFG fellowship recipient.

Email: marc.somssich@unimelb.edu.au

Selected References:

Somssich M, Bleckmann A, Simon R. Shared and distinct functions of the pseudokinase CORYNE (CRN) in shoot and root stem cell maintenance of Arabidopsis. J Exp Bot, 2016

Somssich M, Ma Q, Weidtkamp-Peters S, Stahl Y, Felekyan S, Bleckmann A, Seidel CAM, Simon R. Real-time dynamics of peptide ligand–dependent receptor complex formation in planta. Science Signaling, 2015

Lindner M, Simonini S, Kooiker M, Gagliardini V, Somssich M, Hohenstatt M, Simon R, Grossniklaus U, Kater MM. TAF13 interacts with PRC2 members and is essential for Arabidopsis seed development. Dev Biol, 2013

 

Dr Edwin Lampugnani

edwin-lampugnani-3My research: My current work focuses on the development of a novel in planta protein-protein interaction method and the turn-over of proteins in a plant cell. I have also been exploring how cellulose is made in the different walls of the developing Arabidopsis flower; a superb system for studying organ development.

About me: I completed my PhD at Monash University (Australia) under the guidance of Prof. David R. Smyth in the field of developmental plant genetics using the model plant Arabidopsis thaliana. My PhD project involved examining how organ primordia are initiated in the flowers of Arabidopsis thaliana, and the genetic factors and pathways involved in this process. I have been able to show that petal development is triggered by the chemical hormone auxin. When the shape of flower buds is disrupted by mutation, auxin accumulation is affected and petals do not arise. Thus floral architecture is established by the finely-tuned interplay of growth gene and hormone action.

After I completed my PhD in 2011 I undertook a post-doctoral position with Assoc. Prof. Ed Newbigin and Prof Tony Bacic investigating the cell and molecular biology of cell wall synthesis with a particular emphasis on arabinan and xyloglucan biosynthesis. We used Nicotiana alata pollen tubes as a model to study cell wall biosynthesis because of their relatively simple structure and their ability to grow rapidly in culture. In 2014 I moved to the ARC Centre of Excellence in Plant Cell Walls where I continued to investigate the cell and molecular biology of cell wall synthesis, but this time with a particular emphasis on understanding how grasses make the two main non-cellulosic polysaccharides, mixed linkage (1,3;1,4)-β-glucan (β-glucan) and arabinoxylan, in order to manipulate cereal grain wall composition. In 2016 I joined the Persson Cell Wall biology research group where I am developing a number of novel technologies to study protein-protein interactions and protein turnover.

Email: Edwin.lampugnani@unimelb.edu.au

Selected References:

Lampugnani ER, Kilinc A and Smyth DR. (2013). Auxin controls petal initiation in Arabidopsis. Development; 140(1):185-194.

Lampugnani ER, Ho YY, Moller IE, Koh PL, Golz JF, Bacic A, Newbigin E (2016). A Glycosyltransferase from Nicotiana alata Pollen Mediates Synthesis of a Linear (1,5)-α-L-arabinan When Expressed in Arabidopsis. Plant Physiology; 170: 1962-1974.

Lampugnani ER†, Wilson SM†, Ho YY†, Van de Meene AML, Bacic A and Doblin MS (2015). Determining the subcellular location of (1→3, 1→4)-β-D-glucan and its synthesis machinery: insights into the synthesis mechanism. Plant Cell; 27:754-771.

 

Dr Ghazanfar Khan

Cérémonie d'ouverture des cours et de remise des prix de la faculté de biologie et de médecine 22.09.2016My Research: Plant biomass is largely composed of cell wall material. These rigid cell walls encase plant cells, and biosynthesis and dynamic rearrangements of cell walls therefore drive plant growth. Suboptimal nutrient availability is one of the major growth limiting factor for plants and causes extensive losses to agriculture. However, how nutrient availability affects cell walls is largely unknown. My research focuses on identification of cell wall modification in response to changes in nutrient availability and the genetic mechanisms involved in this process. I use advanced microscopic techniques to image cell walls in response to different nutrient concentrations. Additionally, I am setting up a genetic screen to identify genes involved in the regulation of cell walls in response to changes in nutrient availability.

About me: I completed my Master in 2009 at the University of Paris Diderot, in the lab of Prof. Martin Crespi at the CNRS in Gif-sur-Yvette, France, where I subsequently worked until 2011. I investigated the role of microRNAs in the root development and architecture in Medicago trucatula. After my position in France, I moved to Switzerland, where I earned my PhD in 2016 at the university of Lausanne, under the supervision of Prof. Yves Poirier. During my PhD, I tackled the question of how plants coordinate the transport of different nutrients, and how plants respond to simultaneous stresses. Through a reverse genetic approach, I could identify key genes involved in the coordination of phosphate and zinc transport. I further identified the defence hormone jasmonic acid as a novel regulator of phosphate starvation signalling. My work provides therefore an insight into how the level of nutrient supply can impact the growth and defence of plants. This is of global importance, since phosphate-based fertilizers and plant pest protection are the two major cost factors of modern day agriculture. I joined the Persson Lab at the University of Melbourne in November 2016, as a Swiss National Science Foundation early postdoc mobility fellow.

Email: ghazanfar.khan@unimelb.edu.au

Selected references:

Khan GA, Vogiatzaki E, Glauser G, Poirier Y (2016) Phosphate Deficiency Induces the Jasmonate Pathway and Enhances Resistance to Insect Herbivory. Plant Physiology 171: 632–644

Khan GA*, Bouraine S*, Wege S, Li Y, de Carbonnel M, Berthomieu P, Poirier Y and Rouached H (2014) Coordination between zinc and phosphate homeostasis involves the transcription factor PHR1, the phosphate exporter PHO1 and its homologue PHO1;H3 in Arabidopsis. Journal of Experimental Botany. 65(3):871–884. * These authors contributed equally to this work.

Khan GA *, Bazin J *, Combier JP, Bustos-Sanmamed P, Debernardi JM, Rodriguez R, Sorin C, Palatnik J, Hartmann C, Crespi M and Lelandais‐Brière C, (2013). miR396 affects mycorrhization and root meristem activity in the legume Medicago truncatula. Plant Journal. 74(6):920–934. * These authors contributed equally to this work.

 

PhD students

Zheng Li

My research: Plants typically contain two different types of cell walls; a primary wall that is being deposited around all growing cells, and a secondary wall that is produced in cells with specialised functions once they have ceased to grow. My current research interest is to explore the transition from primary to secondary cell walls. In particular, I am studying changes in transcriptional, metabolic and posttranscriptional events during secondary cell wall formation. To study these changes, I used a hormone-inducible transcription factor driven system together with some computational biology approaches. In the meantime, I am also involved in a project to establish a protein-protein interaction prediction tool based on protein co-evolution theory.

About me: During my master study at Shanghai Jiao Tong University in China (2011-2014), I studied the interaction between plants and Xanthomonas, a large group of pathogenic bacteria. The disease susceptibility gene I identified explained the genetic cause of citrus canker disease, and it is now being used as an excellent candidate to generate resistant citrus lines. In 2014, I joined the Staffan Persson’s group at Max Planck Institute of Molecular Plant Physiology in Germany as a guest PhD student; and in 2015, I moved together with other group members to University of Melbourne to continue my research as a PhD candidate.

Email: liz7@student.unimelb.edu.au

Selected References:

Li Z, Zou, L, Ye G, Xiong L, Ji Z, Zakria M, Hong N, Wang G, Chen G. A Potential Disease Susceptibility Gene CsLOB of Citrus Is Targeted by a Major Virulence Effector PthA of Xanthomonas citri subsp. citri. Molecular Plant, 2014

Li Z, Fernie AR. Persson S. Transition of Primary to Secondary Cell Wall Synthesis. Science Bulletin, 2016.

Li Z, Omranian N, Neumetzler L, Wang T, Herter T, Usadel B, Demura T, Giavalisco P, Nikoloski Z, Persson S. A Transcriptional and Metabolic Framework for Secondary Wall Formation in Arabidopsis. Plant Physiology, 2016.

 

Amelie Mendrinna

AmelieFotoEDUCATION
• PhD student, Max Planck Institute of Molecular Plant Physiology, Potsdam (2013-2014)
• MSc Molecular and Cell Biology, Free University of Berlin (2010-2013)
• BSc Biochemistry, University of Halle-Wittenberg (2007-2010)

RESEARCH INTERESTS
I am generally interested in plant tip growth that occurs in root hairs and pollen tubes. In particular, I am fascinated with how the various extra- and intracellular components, including calcium dynamics, reactive oxygen species and pH, the cytoskeleton and vesicular trafficking are coordinated within the plant signalling framework during tip growth.

Currently, I am working on signalling processes that help to maintain cell wall integrity during root hair growth. How environmental growth-regulating stimuli are sensed and integrated into signals that modulate the dynamic structure of the cell wall remains mostly unknown.

I am using reverse genetics, fluorescence microscopy and molecular biological approaches to elucidate the molecular machinery behind one signalling route for root hair growth.

Email: amendrinna@student.unimelb.edu.au

Selected References

Ruprecht C, Mendrinna A, Tohge T, Sampathkumar A, Klie S, Fernie AR, Nikoloski Z, Persson S, Mutwil M. (2016) FamNet: A Framework to Identify Multiplied Modules Driving Pathway Expansion in Plants. Plant Physiol. 170: 1878-94.

Mendrinna A, Persson S. (2015) Root hair growth: it’s a one way street. F1000Prime Rep. 7:23

Hofferek V, Mendrinna A, Gaude N, Krajinski F, Devers EA. (2014) MiR171h restricts root symbioses and shows like its target NSP2 a complex transcriptional regulation in Medicago truncatula. BMC Plant Biol. 14:199

 

Jacqueline Nowak

jn_imageMy research: My current research interests are the interaction and dynamics of cytoskeletal components like actin filaments and microtubules in plant cells. Therefore, I work with labelled images from techniques such as spinning disc confocal microscopy and an automated framework for segmenting and registering images in different cell types. Here, I also try to expand the functions of already existing algorithm in Python to track filaments over time. Another project is the development of a 3D cell wall root atlas from antibody-labelled root sections to investigate co-localization between epitopes. Furthermore, I am working with transcriptomics data to investigate second cell wall formation in Arabidopsis seedlings.

About me: I did my master study in Bioinformatics at the University of Potsdam in Germany (2012-2015) and meanwhile worked on a project at the Max-Planck Institute of Molecular Plant Physiology involving the extraction and analysis of networks from cytoskeletal components in plants. I wrote my master thesis at the Karolinska Institute in Stockholm, Sweden where I worked on identifying microRNAs from small RNA sequencing data in salamander in the absence of a reference genome. Finally, in 2016 I started my PhD at the University of Melbourne and the University of Potsdam/Max-Planck Institute of Molecular Plant Physiology as first joint PhD student between those institutes, where I combine both my experience in image processing and transcriptomics data analysis.

Email: JNowak@mpimp-golm.mpg.de

Selected References:

Breuer D, Nowak J, Ivakov A, Somssich M, Persson S, Nikoloski Z. (2017) System-wide organization of actin cytoskeleton determines organelle transport in plant cells. Proc Natl Acad Sci U S A. 114: E5741-E5749.

 

Pawel Gluza

OLYMPUS DIGITAL CAMERAMy research: The nucleotide sugars, which constitute the building bricks of cell wall polysaccharides and glycan residues of glycoproteins and glycolipids, are most often synthesized in the cytosol, imported into the Golgi lumen by nucleotide sugar transporters (NSTs) and incorporated into substrates by glycosyltransferases (GTs). Surprisingly, recent studies have shown that while some NSTs show a broad substrate specificity in vitro, in plant cells they can have impact only on specific sugar polymers, hinting at the possibility that substrates are channelled by NST complexes assembled in conjunction with corresponding GTs. In my project I combine various protein-protein interaction studies, cutting edge microscopy, mass spectrometry and preparations of native complexes from Golgi-enriched samples to provide a full overview of the NSTs-GTs interplay in plant cells.

About me: I have completed my MSc and BSc studies while being a part of Department of Cellular Molecular Biology at the University of Wroclaw. Here, I researched the physiological properties of FtsH4 protease and the changes that its knockout imposes on the Arabidopsis mitochondrial sub-proteome. During my MSc studies I was also granted a chance to spend an internship at the Max Planck Institute of Molecular Plant Physiology in Potsdam, Germany, where I was involved in a project aiming to create a novel method of studying interactomes in plants. After my graduation, I applied for the International Max Planck Research School and was offered a position as a PhD candidate in the freshly launched Melbourne-Potsdam joint PhD programme.

Email: pgluza@student.unimelb.edu.au

 

Jana Verbančič

My research: Cell walls represent the single largest investment of the plant´s carbon resources used for growth. I am interested in how plants use specific sugar-signalling metabolites to decide how, when and where to invest this carbon capital. Since primary cell walls are largely comprised of cellulose, which is made by cellulose synthase (CesA) complexes, I am looking at their trafficking to and from the plasmalemma and interactions in conditions, where carbon status is altered. I use a novel stable-isotope (13C) labelling technique for flux analysis, mass spectrometry, confocal microscopy and protein-protein interaction methods.

About me: I finished my bachelor and master studies in Biochemistry at the University of Ljubljana in Slovenia (2010-2016). I was characterizing and researching the mechanism of action of the protein mixed lineage kinase domain-like (MLKL) in E. coli and HEK293T cells. MLKL acts in a programmed cell death pathway, called necroptosis or TNF-induced necrosis and high levels of this protein and another kinase, RIP3, are associated with different inflammatory diseases in vertebrates. At the end of 2015 I completed an internship at the Max Planck Institute of Molecular Plant Physiology (MPI-MP) in Potsdam, Germany, where I discovered the world of plants. In December 2016 I started my joined PhD as a project between the MPI-MP/University of Potsdam and University of Melbourne.

Email: jverbancic@student.unimelb.edu.au/verbancic@mpimp-golm.mpg.de

Selected References:

Verbančič J, Lunn JE, Stitt M, Persson S. Carbon supply and the regulation of cell wall synthesis. (2017) Mol Plant

 

Hsiang-Wen Chen

My research: My project is to reveal how microtubules, cell plate, and cellulose synthesis are coordinated during cell division. I will also investigate how certain proteins that interact with microtubules and cellulose synthase contribute to this process. I will utilize high-end confocal microscopy, electron microscopy, protein structural estimates and in vitro based biochemical analyses to investigate the above.

About me: I am a fan of the dynamic and vivid movement of plants. Aside from tropism and nastic movements, I am especially interested in a helical and constitutive plant nutation, called circumnutation. Circumnutation is thought to be important for plant shoot climbing and root penetrating although the driven force of this movement is still under debate.  To find out the mystery of this phenomena, I started my path to become a plant scientist. My masters research (National Taiwan University, Department of Agronomy, Taiwan) was to uncover the hormone signaling transduction pathway of the light-induced wavy-root morphology of Oryza Sativa. We also found that environmental stimuli can alter circumnutation patterns and eventually cause different phenotypes in rice seminar root. To be more properly trained in scientific thinking, I became a research assistant (Institute of Plant and Microbial Biology, Academia Sinica, Taiwan) after I was awarded my masters degree. My main project was to identify the molecular mechanisms of light-regulated alternative splicing in Physcomitrella patens by using RNAseq.

Currently, I am a Ph.D. student in the joint program of the University of Melbourne (Australia) and the University of Postdam/Max-Planck Institute of Molecular Plant Physiology (Germany). I aim to gain deep knowledge about cell wall synthesis as well as cell biology during my Ph.D. period.

Email: hsiangc@student.unimelb.edu.au

References

Chen H.W., Shao K.H., Wang S.J. (2016) Light-mediated modulation of helix angle and rate of seminal root tip movement determines root morphology of young rice seedlings. Plant Signaling & Behavior.

Chen H.W., Shao K.H., Wang S.J. (2015) Light-modulated seminal wavy roots in rice mediated by nitric oxide-dependent signaling. Protoplasma:1-14.

 

Mike Ogden

Research: Soil nutrients, such as phosphorus, nitrogen, and sulfur, are essential for plant growth. When plants are grown in nutrient-deficient soil, root growth and architecture are drastically altered. As each plant cell is surrounded by a complex and dynamic cell wall, it therefore follows that changes in root architecture caused by nutrient deficiency should be mediated by changes in cell wall composition and biosynthesis. My research aims to identify and characterize the molecular mechanisms involved in cell wall modification in response to external nutrient availability. I will use advanced microscopy and phospho-proteomic analyses to characterize changes in cell wall biosynthetic enzyme activity during nutrient deficient growth. Comprehensive metabolite profiling will be undertaken to assess how metabolite levels change under varying degrees of nutrient availability. Additionally, mutants that show hypersensitivity to high nutrient levels will be investigated to identify pathways which link nutrient signaling to cell wall composition. Knowledge gained from this research may provide a basis for improving plant growth in nutrient-deficient soils.

About me: I earned my Bachelor of Science (Honours) from the University of Prince Edward Island in Canada, and my Master of Science from McGill University in Montreal, Canada. At McGill University, my research project involved investigating the molecular pathways which target pectins from the Golgi to specific plasma membrane domains where they are secreted to the cell wall. I was accepted into the Melbourne-Potsdam joint PhD programme between the University of Melbourne and the Max Planck Institute of Molecular Plant Physiology. My research is a collaborative project between the labs of Professors Roessner and Persson (University of Melbourne), and Hoefgen (Max Planck Institute).

Email: ogdenm@student.unimelb.edu.au

References

Ogden, M., and Lacroix, C. 2017. Comparative development of simple and compound leaves in the genus Cecropia. Botany. 95(2): 185-193.

 

Huizhen Xu

My research: Secondary cell walls provide plants with mechanical support and is the major renewable natural resource of plant biomass. Cellulose is the major component of secondary cell walls. My research is mainly about how phosphorylation of secondary cell wall cellulose synthases affect the synthesis of cellulose. I will use the VND7 inducible system to visualize the secondary cell wall synthesis process in living cells. I am also interested in how xylan and POM2/CSI1 influence the speed and direction of secondary cell wall CSCs during cellulose production.

About me: I finished my bachelor studies at Soochow University in 2013, and continued my master research in food biotechnology at China Agricultural University till 2015. My master research is about the mechanisms of how transcription factor Colorless None-Ripening (CNR) regulate tomato fruit ripening through promoter methylation. After graduation, I worked in Archer Daniels Midland Company (ADM) for about 2 years. In February 2018, I started my Ph.D. research at the University of Melbourne, and I want to keep exploring the mystery of plants, especially the synthesis of secondary cell wall.

 

Liu Wang

My research: Two plant-specific proteins, companion of cellulose synthase 1 and 2 (CC1 and CC2) are components of cellulose synthase complexes (CSCs) and can protect cellulose synthesis capacity during salt stress. However, how CC proteins function and whether can we modify CC proteins to improve salt tolerance of plants still remain unclear. I will explore how changes in the phosphorylation of CC proteins influence their function, cellulose synthesis and salt tolerance of plants. I will also identify whether the function of CC proteins in response to salt stress works via the ABA pathway.

About me: During my master study at China Agricultural University (2015-2018), I majored in Food Biotechnology and I focused on exploring the functions of mitogen-activated protein kinases (MAPKs) in tomato. My research program was mainly about exploring the functions of SlMAPK1/3 in response to drought stress in tomato plants. We found that SlMAPK1/3 are involved in drought response by activating antioxidant enzymes, reducing oxidative damage, and modulating transcription of some stress-related genes.

Currently, I am a PhD student sponsored by China Scholarship Council and the University of Melbourne. I aim to study more about how plants respond to abiotic stresses and to establish means to improve salt tolerance of plants via a new pathway that is directly connected to cell wall synthesis.

Email: liu.wang@student.unimelb.edu.au

References:

Wang, L.; Zhao, R.; Zheng, Y.; Chen, L.; Li, R.; Ma, J.; Hong, X.; Ma, P.; Sheng, J.; Shen, L. (2017). SlMAPK1/2/3 and antioxidant enzymes are associated with H2O2-induced chilling tolerance in tomato plants. Journal of Agricultural and Food Chemistry, 65 (32), 6812-6820.

Wang, L.; Chen L.; Li, R.; Zhao, R.; Yang M.; Sheng, J.; Shen, L. (2017). Reduced drought tolerance by CRISPR/Cas9-mediated SlMAPK3 mutagenesis in tomato plants. Journal of Agricultural and Food Chemistry, 65 (39), 8674-8682.

Wang, L.; Zhao, R.; Li, R.; Yu, W.; Yang M.; Sheng, J.; Shen, L. (2017). Enhanced drought tolerance in tomato plants by overexpression of SlMAPK1. Plant Cell, Tissue and Organ Culture, 2018, 133 (1), 27-38.

 

Lab assistant