Recherche

Wegmüller Sarah

Adjoint-e scientifique HES A

Compétences principales

Recombinant peptides and proteins

Adjoint-e scientifique HES A

Bureau: ENP.19.N109

HES-SO Valais-Wallis - Haute Ecole d'Ingénierie
Rue de l'Industrie 23, 1950 Sion, CH

Domaine
Chimie et sciences de la vie

Filière principale
Technologies du vivant

BSc HES-SO en Technologies du vivant - HES-SO Valais-Wallis - Haute Ecole d'Ingénierie

Molecular Biology
Biochemistry
Bioinformatics

En cours

Clone validation using the Oxford Nanopore System

Rôle: Requérant(e) principal(e)

Financement: Socle_Ra&D_ITV

Description du projet :

The aim of this project is to evaluate the Oxford Nanopore sequencing for clone validation. Plasmids received from external sources or created by PCR-based methods often contain point mutations, which may initially go unnoticed, but can pose problems in further cloning steps or gene expression. In the first part of the project the feasibility, accuracy and time and material cost of sequencing of plasmids with the Oxford nanopore method is evaluated. In a second part methods will be developped to analyze strains with multiple plasmid insertions and strains, where plasmids have been used to insert sequences into the genome of microorganisms by CRISPR/Cas, for example.

Equipe de recherche au sein de la HES-SO: Wegmüller Sarah

Durée du projet: 01.03.2022

Statut: En cours

Terminés

Bestimmung der Transgenkopienzahl

AGP

Rôle: Collaborateur/trice

Requérant(e)s: VS - Institut Technologies du vivant

Financement: Lonza AG

Description du projet : Bestimmung der Transgenkopienzahl

Equipe de recherche au sein de la HES-SO: Schmid Sergio , Pistoletti Blanchet Gordana , Wegmüller Sarah

Partenaires académiques: VS - Institut Technologies du vivant

Durée du projet: 11.10.2016 - 31.12.2017

Montant global du projet: 21'700 CHF

Statut: Terminé

Développement d'une méthode universelle et spécifique pour le dosage de protéines recombinantes

AGP

Rôle: Collaborateur/trice

Requérant(e)s: VS - Institut Technologies du vivant

Financement: HES-SO Rectorat

Description du projet : Malgré l'importance croissante des protéines recombinantes il n'existe actuellement aucune méthode applicable de manière générale permettant de doser celles-ci de manière rapide, sensible, spécifique, automatique et directement dans des solutions complexes comme du sérum. Une telle technique donnerait accès à des possibilités nouvelles comme le suivi de la production de protéines ou le dosage de protéines thérapeutiques dans le sang. Ce projet visera à développer et valider une telle méthode de dosage sur la base de techniques de fluorescence avancées.

Equipe de recherche au sein de la HES-SO: Prim Denis , Crelier Simon , Schmid Sergio , Dufresne Rémy , Wegmüller Sarah , Marti Roger , Segura Jean-Manuel , Mamula Steiner Olimpia

Partenaires académiques: VS - Institut Technologies du vivant; FR - EIA - Institut ChemTech

Durée du projet: 01.01.2012 - 30.09.2013

Montant global du projet: 147'500 CHF

Statut: Terminé

Polymorphism determination to improve nutrition recommendations

AGP

Rôle: Collaborateur/trice

Requérant(e)s: VS - Institut Technologies du vivant, Schnyder Bruno, VS - Institut Technologies du vivant

Financement: Swiss Food Research

Description du projet : The effects of gene polymorphisms (mutations) on lipoprotein metabolism in response to dietary fat and cholesterol have drawn increasing attention in recent years. The molecular mechanisms underlying these effects are supposed to be useful in identifying and counselling certain individuals to avoid high-fat diets, which would otherwise specifically increase their risk of developing hyperlipidemia and thus increase their risk of metabolic disorders and diabetes type 2. More and more data are available on the effects of dietary fat and cholesterol, hence, the causal relationship with reported genetic factors is warranted to be applied.

Equipe de recherche au sein de la HES-SO: Eyer Kurt , Schnyder Bruno , Wegmüller Sarah , Crettenand Alexia

Partenaires académiques: VS - Institut Technologies du vivant; Energy4life AG; Schnyder Bruno, VS - Institut Technologies du vivant

Durée du projet: 15.08.2010 - 15.09.2011

Montant global du projet: 16'000 CHF

Statut: Terminé

2014

Recombinant peptide production in microbial cells

Article scientifique

Wegmüller Sarah, Schmid Sergio

Current Organic Chemistry, 2014 , vol. 18, no 8

Lien vers la publication

Résumé:

Bioactive peptides are used in diagnostics and as therapeutic agents in a variety of diseases, as well as inhibitors of bacterial
growth in food industry. Recent technological advances in delivery and formulation tools have resuscitated the field of peptide therapeutics,
resulting in approx. 60 approved peptide drugs and an annual predicted growth rate of the market of approximately 10%. Whilst the
majority of peptides are currently produced by chemical synthesis, recombinant peptide production will become more important in the
near future and will play a key role in the competition landscape of peptide therapeutics companies. In particular, this is the case for long
and complex peptides containing natural amino acids. Although development of a biotechnological process for recombinant production
can be time consuming, larger quantities of peptide can be produced and the environmental impact of the generated waste is lower compared
to chemical synthesis. However, recombinant peptide expression must overcome several obstacles in order to be cost-effective and
competitive with chemical synthesis. The present review focuses on recombinant peptide production in microbial expression platforms, in
particular the expression hosts Escherichia coli and yeast and their respective vectors. Strategies which have been successful in solving
drawbacks such as degradation of peptides by cellular proteases, solubility and purification issues, toxicity of recombinant peptides for
the producer cells and the introduction of posttranslational modifications are described.

2013

The cis-acting CTTC–P1BS module is indicative for gene function of LjVTI12, a Qb-SNARE protein gene that is required for arbuscule formation in Lotus japonicus

Article scientifique

Frédéric Lota, Wegmüller Sarah, Benjamin Buer, Sato Shusei, Andrea Bräutigam, Benjamin Hanf, Marcel Bucher

The Plant Journal, 2013 , vol. 74, pp. 280-293

Résumé:

The majority of land plants live in symbiosis with arbuscular mycorrhizal fungi from the phylum
Glomeromycota. This symbiosis improves acquisition of phosphorus (P) by the host plant in exchange for
carbohydrates, especially under low-P availability. The symbiosome, constituted by root cortex cells accommodating
arbuscular mycorrhizal fungal hyphae, is the site at which bi-directional exchange of nutrients
and metabolites takes place. Uptake of orthophosphate (Pi) in the symbiosome is facilitated by mycorrhizaspecific
plant Pi transporters. Modifications of the potato Pi transporter 3 (StPT3) promoter were analysed
in transgenic mycorrhizal roots, and it was found that the CTTC cis-regulatory element is necessary and
sufficient for a transcriptional response to fungal colonization under low-Pi conditions. Phylogenetic footprinting
also revealed binary combination of the CTTC element with the Pi starvation response-associated
PHR1-binding site (P1BS) in the promoters of several mycorrhiza-specific Pi transporter genes. Scanning of
the Lotus japonicus genome for gene promoters containing both cis-regulatory elements revealed a strong
over-representation of genes involved in transport processes. One of these, LjVTI12, encoding a member of
the SNARE family of proteins involved in membrane transport, exhibited enhanced transcript levels in Lotus
roots colonized with the arbuscular mycorrhizal fungus Glomus intraradices. Down-regulation of LjVTI12 by
RNA interference resulted in a mycorrhiza-specific phenotype characterized by distorted arbuscule morphology.
The results highlight cooperative cis-regulation which integrates mycorrhiza and Pi starvation signaling
with vesicle trafficking in symbiosome development.

2010

Toxinbildende Staphylokokken

Article professionnel

Wegmüller Sarah, Esther Schmitt, Schnyder Bruno

Alimenta, 2010

Résumé:

Staphylokokken können Lebensmittelvergiftungen verursachen. Eine an der Fachhochschule HES-SO Wallis neu entwickelte Methode kann nachweisen,
ob eine Probe enterotoxinbildende Staphylokokken enthält.

2009

Chasing the structures of small molecules in arbuscular mycorrhizal signaling

Article scientifique ArODES

Marcel Bucher, Sarah Wegmüller, David Drissner

Current Opinion in Plant Biology, 2009, vol. vol. 12, no. 4, pp. 500-507

Lien vers la publication

Résumé:

The arbuscular mycorrhiza (AM) is a symbiosis between most terrestrial plants and fungi of the ancient phylum Glomeromycota. AM improves the uptake of water and mineral nutrients, such as phosphorus (P) and nitrogen (N), of the host plant in exchange for photosynthetically fixed carbon. Successful colonization and a functional interaction between host plant and mycobiont are based upon exchange of signaling molecules at different stages of symbiosis development. Strigolactones, a novel class of plant hormones, are secreted by plant roots stimulating presymbiotic growth of AM fungi. Fungi release soluble signaling molecules, the enigmatic ‘Myc factors’, that activate early symbiotic root responses. Lysophosphatidylcholine is a lipophilic intraradical mycorrhizal signal triggering plant phosphate transporter gene expression late in AM development through a P-controlled transcriptional mechanism. This enables uptake of orthophosphate released from the AM fungus.

Plasmid DNA isolation from the gram-positive bacterium pediococcus damnosus using a modified PureYield™ plasmid midiprep system protocol

Article professionnel ArODES

Sarah Wegmüller, Sergio Schmid

Promega,

Lien vers la publication

Development and function of the arbuscular mycorrhizal symbiosis in petunia

Chapitre de livre ArODES

D.M.R. Sekhara Reddy, Sergio Svistoonoff, Florence Breuillin, Sarah Wegmüller, Marcel Bucher, Didier Reinhardt

Dans Gerats, Tom, Strommer, Judith, Petunia : evolutionary, developmental and physiological genetics (pp. 131-156). 2009, New York (NY) : Springer

Lien vers la publication

Résumé:

The majority of terrestrial plants live in symbiotic associations with fungi or bacteria that improve their nutrition. Critical steps in such a symbiosis are mutual recognition and subsequent establishment of an intimate association that involves the penetration of plant tissues and, in many cases, the invasion of individual host cells by the microbial symbiont. The most widespread symbiosis of plants is the arbuscular mycorrhizal (AM) symbiosis, which can improve plant nutrition and stress resistance. The AM symbiosis is controlled by intrinsic factors such as SYM symbiosis genes, and extrinsic factors such as nutrients. Important experimental systems in symbiosis research are legumes (Medicago truncatula and Lotus japonicus) and grasses (rice and maize), but Solanaceae are also catching up. In this chapter, we summarize recent advances in AM research on Petunia, which complement ongoing efforts in the AM research community.

Development and Function of the Arbuscular Mycorrhizal Symbiosis in Petunia.

Chapitre de livre

DMR Sekhara Reddy, Sergio Svistoonoff, Florence Breuillin, Wegmüller Sarah, Marcel Bucher, Didier Reinhardt

, Petunia: Evolutionary, Developmental and Physiological Genetics. 2009, New York : Springer-Verlag

Résumé:

The majority of plants live in symbiotic associations with fungi or bacteria that improve their nutrition. Critical steps in such a symbiosis are mutual recognition and subsequent establishment of an intimate association that involves the penetration of plant tissues and, in many cases, the invasion of individual host cells by the microbial symbiont. The most widespread symbiosis of plants is arbuscular mycorrhizal (AM) symbiosis, which can improve plant nutrition. The AM symbiosis is controlled by intrinsic factors, for example the SYM genes, and extrinsic factors such as nutrients. Important experimental systems in sym-biosis research are legumes (Medicago truncatula and Lotus japonicus) and grasses (rice and maize), but Solanaceae are catching up. Here, we summarize recent advances in AM research on Petunia, which complement ongoing efforts in the AM research community.

Chasing the structures of small molecules in arbuscular mycorrhizal signalling

Article scientifique

Marcel Bucher, Wegmüller Sarah, David Drissner

Current Opinion in Plant Biology, 2009 , vol. 12, pp. 500-507

Résumé:

The arbuscular mycorrhiza (AM) is a symbiosis between most
terrestrial plants and fungi of the ancient phylum
Glomeromycota. AM improves the uptake of water and mineral
nutrients, such as phosphorus (P) and nitrogen (N), of the host
plant in exchange for photosynthetically fixed carbon.
Successful colonization and a functional interaction between
host plant and mycobiont are based upon exchange of
signaling molecules at different stages of symbiosis
development. Strigolactones, a novel class of plant hormones,
are secreted by plant roots stimulating presymbiotic growth of
AM fungi. Fungi release soluble signaling molecules, the
enigmatic ‘Myc factors’, that activate early symbiotic root
responses. Lysophosphatidylcholine is a lipophilic intraradical
mycorrhizal signal triggering plant phosphate transporter gene
expression late in AM development through a P-controlled
transcriptional mechanism. This enables uptake of
orthophosphate released from the AM fungus.

2008

A transgenic dTph1 insertional mutagenesis system for forward genetics in mycorrhizal phosphate transport of Petunia

Article scientifique ArODES

Sarah Wegmüller, Sergio Svistoonoff, Didier Reinhardt, Jeroen Stuurman, Nikolaus Amrhein, Marcel Bucher

The Plant Journal, 2008, vol. 54, no. 6, pp. 1115-1127

Lien vers la publication

Résumé:

The active endogenous dTph1 system of the Petunia hybrida mutator line W138 has been used in several forward-genetic mutant screens that were based on visible phenotypes such as flower morphology and color. In contrast, defective symbiotic phosphate (Pi) transport in mycorrhizal roots of Petunia is a hidden molecular phenotype as the symbiosis between plant roots and fungi takes place below ground, and, while fungal colonization can be visualized histochemically, Pi transport and the activity of Pi transporter proteins cannot be assessed visually. Here, we report on a molecular approach in which expression of a mycorrhiza-inducible bi-functional reporter transgene and insertional mutagenesis in Petunia are combined. Bi-directionalization of a mycorrhizal Pi transporter promoter controlling the expression of two reporter genes encoding firefly luciferase and GUS allows visualization of mycorrhiza-specific Pi transporter expression. A population of selectable transposon insertion mutants was established by crossing the transgenic reporter line with the mutator W138, from which the Pitransporter downregulated (ptd1) mutant was identified, which exhibits strongly reduced expression of mycorrhiza-inducible Pi transporters in mycorrhizal roots.

A transgenic dTph1 insertional mutagenesis system for forward genetics in mycorrhizal phosphate transport of Petunia

Article scientifique

Wegmüller Sarah, Sergio Svistoonoff, Didier Reinhardt, Stuurman Jeroen, Amrhein Nikolaus, Marcel Bucher

The Plant Journal, 2008 , vol. 54, pp. 1115-1127

Résumé:

The active endogenous dTph1 system of the Petunia hybrida mutator line W138 has been used in several
forward-genetic mutant screens that were based on visible phenotypes such as flower morphology and color.
In contrast, defective symbiotic phosphate (Pi) transport in mycorrhizal roots of Petunia is a hidden molecular
phenotype as the symbiosis between plant roots and fungi takes place below ground, and, while fungal
colonization can be visualized histochemically, Pi transport and the activity of Pi transporter proteins cannot be
assessed visually. Here, we report on a molecular approach in which expression of a mycorrhiza-inducible
bi-functional reporter transgene and insertional mutagenesis in Petunia are combined. Bi-directionalization of
a mycorrhizal Pi transporter promoter controlling the expression of two reporter genes encoding firefly
luciferase and GUS allows visualization of mycorrhiza-specific Pi transporter expression. A population of
selectable transposon insertion mutants was established by crossing the transgenic reporter line with the
mutator W138, from which the Pi transporter downregulated (ptd1) mutant was identified, which exhibits
strongly reduced expression of mycorrhiza-inducible Pi transporters in mycorrhizal roots.

2004

Evolutionary conservation of a phosphate transporter in the arbuscular mycorrhizal symbiosis

Article scientifique

Vladimir Karandshov, Réka Nagy, Wegmüller Sarah, Nikolaus Amrhein, Marcel Bucher

PNAS, 2004 , vol. 101, no 16, pp. 6285-6290

Résumé:

Arbuscular mycorrhizae are ancient symbioses that are thought to have originated >400 million years ago in the roots of plants, pioneering the colonization of terrestrial habitats. In these associations, a key process is the transfer of phosphorus as inorganic phosphate to the host plant across the fungus–plant interface. Mycorrhiza-specific phosphate transporter genes and their regulation are conserved in phylogenetically distant plant species, and
they are activated selectively by fungal species from the phylum Glomeromycota. The potato phosphate transporter gene StPT3 is expressed in a temporally defined manner in root cells harboring various mycorrhizal structures, including thick-coiled hyphae. The results highlight the role of different symbiotic structures in phosphorus transfer, and they indicate that cell– cell contact between the symbiotic partners is required to induce phosphate
transport.

Réalisations

Recherche

Wegmüller Sarah

Adjoint-e scientifique HES A

Compétences principales

Molecular biology

Nanopore sequencing

PCR / qPCR

Genomics

Recombinant peptides and proteins

Microbial strain development

High-throughput sequencing

Adjoint-e scientifique HES A