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373 results on '"Rischer, Heiko"'

33. Raspberry Ketone Accumulation in Nicotiana benthamianaand Saccharomyces cerevisiaeby Expression of Fused Pathway Genes

Author

Laurel, Markus, Mojzita, Dominik, Seppänen-Laakso, Tuulikki, Oksman-Caldentey, Kirsi-Marja, and Rischer, Heiko

Abstract

Raspberry ketone has generated interest in recent years both as a flavor agent and as a health promoting supplement. Raspberry ketone can be synthesized chemically, but the value of a natural nonsynthetic product is among the most valuable flavor compounds on the market. Coumaroyl-coenzyme A (CoA) is the direct precursor for raspberry ketone but also an essential precursor for flavonoid and lignin biosynthesis in plants and therefore highly regulated. The synthetic fusion of 4-coumaric acid ligase (4CL) and benzalacetone synthase (BAS) enables the channeling of coumaroyl-CoA from the ligase to the synthase, proving to be a powerful tool in the production of raspberry ketone in both N. benthamianaand S. cerevisiae. To the best of our knowledge, the key pathway genes for raspberry ketone formation are transiently expressed in N. benthamianafor the first time in this study, producing over 30 μg/g of the compound. Our raspberry ketone producing yeast strains yielded up to 60 mg/L, which is the highest ever reported in yeast.

Published
2023
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44. Contrasting Dihydronaphthoquinone Patterns in Closely Related Drosera (Sundew) Species Enable Taxonomic Distinction and Identification

Author

Schlauer, Jan, Hartmeyer, Siegfried R. H., Hartmeyer, Irmgard, Seppänen-laakso, Tuulikki, and Rischer, Heiko

Subjects
chemotaxonomy, drosera, naphthoquinones, QK1-989, Botany, droseraceae, Drosera
Abstract

Dihydronaphthoquinones are described as constituents of sundews (Drosera), Venus flytraps (Dionaea), and dewy pines (Drosophyllum) for the first time. As in the corresponding naphthoquinones, these reduced derivatives may occur in two regio-isomeric series distinguished by the relative position of a methyl group (at position 2 or 7 in the naphthalene skeleton), depending on the taxon. Species producing plumbagin (2-methyljuglone, 1) do commonly contain the corresponding dihydroplumbagin (5), while species containing ramentaceone (7-methyljuglone, 2) also contain dihydroramentaceone (7-methyl-β-dihydrojuglone, 6). So far, only few species containing plumbagin (1) and dihydroplumbagin (5) additionally form dihydroramentaceone (6) but not ramentaceone (2). Thus, subtle but constant differences in the chemism of closely related and morphologically similar species reliably define and distinguish taxa within D. sect. Arachnopus, which is taken to exemplify their chemotaxonomic utility. The joint presence of quinones and hydroquinones allows observations and predictions on the chemical structures and the reactions of these intriguing natural products.

Published
2021

47. Cellular Agriculture:Lab-Grown Foods

Author

Ercili-Cura, Dilek, Barth, Dorothee, Pitkänen, Juha-Pekka, Tervasmäki, Petri, Paananen, Arja, Rischer, Heiko, Nordlund, Emilia, Szilvay, Geza, Ellilä, Simo, Tuomisto, Hanna, Ryynänen, Toni, and Rønning, Sissel Beate

Subjects
Cellular Agriculture, single cell proteins, acellular products, lab grown food, recombinant proteins, gas fermentation, food without fields, cell-cultured meat
Published
2021

49. Additional file 1 of Engineering of Saccharomyces cerevisiae for anthranilate and methyl anthranilate production

Author

Joosu Kuivanen, Kannisto, Matti, Mojzita, Dominik, Rischer, Heiko, Toivari, Mervi, and Jäntti, Jussi

Abstract

Additional file 1: Fig. S1 The workflow of the CRISPR/Cas9 method used in the strain construction. The S. cerevisiae strain was first transformed with the Cas9 expression vector and then with the linear fragments of the sgRNA expression cassette, the sgRNA expression plasmid backbone and the donor DNA. The sgRNA expression cassettes were produced by two PCR reactions. The first PCR produces the target specific 20 nucleotide sequence and results in two fragments. The second PCR then amplifies the whole cassette fusing these fragments together. The sgRNA expression plasmid is formed by homologous recombination in vivo from the sgRNA expression cassette and the plasmid backbone. After each round of genomic integrations, the sgRNA expression plasmid is dropped from the cells by growing on non-selective medium which allows new round of modification to be carried out. Fig. S2 The expression cassette used for the MtAAMT1 expression in the S. cerevisiae strain engineered for ANTH production (strain 4). Fig. S3 Example of UPLC-MS analysis of ANTH and Me-ANTH. The top panel represents the base peak intensity (BPI) chromatograms of analytical standards, ANTH and Me-ANTH as detected by mass spectrometry. The lower panels show the same analysis of production of the compounds by the strain 4 and the strain 4 modified by the expression cassette for MtAAMT1.

Published
2021
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