ORCID Profile
0000-0002-9958-0169
Current Organisation
IT University of Copenhagen
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Publisher: Springer Science and Business Media LLC
Date: 23-06-2022
DOI: 10.1186/S12889-022-13591-1
Abstract: We systematically reviewed the effects of community gardens on physical and psychosocial health, health behaviors and community outcomes. Quantitative studies that examined associations of health, psychosocial or community outcomes with community gardens were included in the review. Studies up to December 2020 were captured from searches of Medline, Web of Science, PsycInfo, EBSCOHost and CAB Abstracts. Data were extracted and study quality including risk of bias was examined. There were 53 studies that met the inclusion criteria. Studies examining associations between community gardens and nutrition or food security were most frequently reported ( k = 23). Other factors examined for associations with community gardens were health ( k = 16), psychosocial ( k = 16) and community outcomes ( k = 7). Effects appeared positive for fruit and vegetable intake, some psychosocial and community outcomes, but mixed for physical health outcomes. Evidence quality overall was low. Community gardening was associated with higher fruit and vegetable intake, positive psychosocial and community outcomes, but poor evidence quality suggests the effects of community gardening may be overestimated.
Publisher: Cold Spring Harbor Laboratory
Date: 24-06-2022
DOI: 10.1101/2022.06.22.497135
Abstract: Extrachromosomal circular DNA of chromosomal origin (eccDNA) can rapidly shape the evolution and adaptation of mitotically iding cells such as tumor cells. However, whether eccDNA has a permanent impact on genome evolution through the germline is largely unexplored. Here, we propose that a large fraction of the syntenic changes that are found between mammalian species are caused by germline transposition of eccDNA. We have previously shown the existence of eccDNA in mammalian meiotic cells. By reanalysis of available synteny maps, we now find that up to 6% of mammalian genomes might have rearranged via a circular DNA intermediate. Hence, eccDNA in the germline is expected to have large effects on evolution of gene order. Extrachromosomal circular DNA (eccDNA) is present in mammalian germline cells showing that eccDNAs are not excluded, repressed or eliminated during meiosis Large eccDNA reinsertions into the genome can change gene synteny in a recognizable pattern based on its circular junction and integration breakpoint. By reanalyzing synteny maps form 8 mammalian species, we show that 6% of genome of the ungulates cow and sheep can be explained by eccDNA insertions. We propose that reinsertion of large eccDNA that are fixed in germline cells may have contributed to speciation barriers and evolution of new species
Publisher: Elsevier BV
Date: 08-2013
DOI: 10.1016/J.IJFOODMICRO.2013.05.006
Abstract: Wine styles are defined by complex and highly erse chemical compositions. Evidence suggests that some of this complexity is determined by the choice of yeast strain used in fermentation. There are hundreds of different commercially available wine yeast strains that, potentially, provide a means by which winemakers can tailor their wines for different consumer market segments. In this study we evaluated the impacts of fermenting Shiraz must with different yeast strains, with a focus on chemical composition and tannin content of the finished wines. Principal Component Analysis (PCA) of the wines indicated that choice of yeast strain had a strong influence on a number of wine compositional parameters, including tannin. In three fermentation experiments, across two vintages and using different winemaking protocols, a compelling case for yeast strain 'signature' was evident. The results demonstrate that there is an opportunity to use commercial wine yeast ersity to modulate red wine composition and, by implication, the style of finished wines.
Publisher: Oxford University Press (OUP)
Date: 15-11-2018
Publisher: Cold Spring Harbor Laboratory
Date: 10-04-2020
Abstract: Aging varies among in iduals due to both genetics and environment, but the underlying molecular mechanisms remain largely unknown. Using a highly recombined Saccharomyces cerevisiae population, we found 30 distinct quantitative trait loci (QTLs) that control chronological life span (CLS) in calorie-rich and calorie-restricted environments and under rapamycin exposure. Calorie restriction and rapamycin extended life span in virtually all genotypes but through different genetic variants. We tracked the two major QTLs to the cell wall glycoprotein genes FLO11 and HPF1 . We found that massive expansion of intragenic tandem repeats within the N-terminal domain of HPF1 was sufficient to cause pronounced life span shortening. Life span impairment by HPF1 was buffered by rapamycin but not by calorie restriction. The HPF1 repeat expansion shifted yeast cells from a sedentary to a buoyant state, thereby increasing their exposure to surrounding oxygen. The higher oxygenation altered methionine, lipid, and purine metabolism, and inhibited quiescence, which explains the life span shortening. We conclude that fast-evolving intragenic repeat expansions can fundamentally change the relationship between cells and their environment with profound effects on cellular lifestyle and longevity.
Publisher: Informa UK Limited
Date: 05-2012
DOI: 10.4161/BBUG.19566
Publisher: American Society for Microbiology
Date: 29-12-2017
Abstract: Flavor compound metabolism is one of the last areas in metabolism where multiple genes encoding biosynthetic enzymes are still unknown. A major challenge is the involvement of side activities of enzymes having their main function in other areas of metabolism. We have applied pooled-segregant whole-genome sequence analysis to identify novel Saccharomyces cerevisiae genes affecting production of phenylethyl acetate (2-PEAc). This is a desirable flavor compound of major importance in alcoholic beverages imparting rose- and honey-like aromas, with production of high 2-PEAc levels considered a superior trait. Four quantitative trait loci (QTLs) responsible for high 2-PEAc production were identified, with two loci each showing linkage to the genomes of the BTC.1D and ER18 parents. The first two loci were investigated further. The causative genes were identified by reciprocal allele swapping into both parents using clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9. The superior allele of the first major causative gene, FAS2 , was dominant and contained two unique single nucleotide polymorphisms (SNPs) responsible for high 2-PEAc production that were not present in other sequenced yeast strains. FAS2 encodes the alpha subunit of the fatty acid synthetase complex. Surprisingly, the second causative gene was a mutant allele of TOR1 , a gene involved in nitrogen regulation. Exchange of both superior alleles in the ER18 parent strain increased 2-PEAc production 70%, nearly to the same level as in the best superior segregant. Our results show that polygenic analysis combined with CRISPR/Cas9-mediated allele exchange is a powerful tool for identification of genes encoding missing metabolic enzymes and for development of industrial yeast strains generating novel flavor profiles in alcoholic beverages. IMPORTANCE Multiple reactions in flavor metabolism appear to be catalyzed by side activities of other enzymes that have been difficult to identify. We have applied genetic mapping of quantitative trait loci in the yeast Saccharomyces cerevisiae to identify mutant alleles of genes determining the production of phenylethyl acetate, an important flavor compound imparting rose- and honey-like aromas to alcoholic beverages. We identified a unique, dominant allele of FAS2 that supports high production of phenylethyl acetate. FAS2 encodes a subunit of the fatty acid synthetase complex and apparently exerts an important side activity on one or more alternative substrates in flavor compound synthesis. The second mutant allele contained a nonsense mutation in TOR1 , a gene involved in nitrogen regulation of growth. Together the two alleles strongly increased the level of phenylethyl acetate. Our work highlights the potential of genetic mapping of quantitative phenotypic traits to identify novel enzymes and regulatory components in yeast metabolism, including regular metabolic enzymes with unknown side activities responsible for biosynthesis of specific flavor compounds. The superior alleles identified can be used to develop industrial yeast strains generating novel flavor profiles in alcoholic beverages.
Publisher: American Society for Microbiology
Date: 05-09-2018
Abstract: Basic research with laboratory strains of the yeast Saccharomyces cerevisiae has identified the structural genes of most metabolic enzymes, as well as genes encoding major regulators of metabolism. On the other hand, more recent work on polygenic analysis of yeast bio ersity in natural and industrial yeast strains is revealing novel components of yeast metabolism. A major ex le is the metabolism of flavor compounds, a particularly important property of industrial yeast strains used for the production of alcoholic beverages. In this work, we have performed polygenic analysis of production of ethyl acetate, an important off-flavor compound in beer and other alcoholic beverages. To increase the chances of identifying novel components, we have used in parallel a wild-type strain and a strain with a deletion of ATF1 encoding the main enzyme of acetate ester biosynthesis. This revealed a new structural gene, EAT1 , encoding a putative mitochondrial enzyme, which was recently identified as an ethanol acetyl-CoA transferase in another yeast species. We also identified a novel regulatory gene, SNF8 , which has not previously been linked to flavor production. Our results show that polygenic analysis of metabolic traits in the absence of major effector genes can reveal novel structural and regulatory genes. The mutant alleles identified can be used to affect the flavor profile in industrial yeast strains for production of alcoholic beverages in more subtle ways than by deletion or overexpression of the already known major effector genes and without significantly altering other industrially important traits. The effect of the novel variants was dependent on the genetic background, with a highly desirable outcome in the flavor profile of an ale brewing yeast.
Publisher: American Society for Microbiology
Date: 06-2011
DOI: 10.1128/AEM.03009-10
Abstract: Sulfur-containing aroma compounds are key contributors to the flavor of a erse range of foods and beverages. The tropical fruit characters of Vitis vinifera L. cv. Sauvignon blanc wines are attributed to the presence of the aromatic thiols 3-mercaptohexan-1-ol (3MH), 3-mercaptohexan-1-ol-acetate, and 4-mercapto-4-methylpentan-2-one (4MMP). These volatile thiols are found in small amounts in grape juice and are formed from nonvolatile cysteinylated precursors during fermentation. In this study, we overexpressed a Saccharomyces cerevisiae gene, STR3 , which led to an increase in 3MH release during fermentation of a V. vinifera L. cv. Sauvignon blanc juice. Characterization of the enzymatic properties of Str3p confirmed it to be a pyridoxal-5′-phosphate-dependent cystathionine β-lyase, and we demonstrated that this enzyme was able to cleave the cysteinylated precursors of 3MH and 4MMP to release the free thiols. These data provide direct evidence for a yeast enzyme able to release aromatic thiols in vitro that can be applied in the development of self-cloned yeast to enhance wine flavor.
Publisher: Elsevier BV
Date: 06-2018
Abstract: Non-conventional yeast species have great capacity for producing erse flavor profiles in production of alcoholic beverages, but their potential for beer brewing, in particular in consecutive fermentations with Saccharomyces cerevisiae, has only poorly been explored. We have screened 17 non-conventional yeast species for production of an appealing profile of flavor esters and phenolics in the first phase of alcoholic fermentation, followed by inoculation with S. cerevisiae to complete the fermentation. For measurement of phenolic compounds and their precursors we developed an improved and highly sensitive methodology. The results show that non-conventional yeast species possess promising potential for enhancement of desirable flavors in beer production. Notable ex les are increasing isoamyl acetate (fruity, banana flavor) by application of P. kluyverii, augmenting ethyl phenolic compounds (spicy notes) with Brettanomyces species and enhancing 4-vinyl guaiacol (clove-like aroma) with T. delbrueckii. All Pichia strains also produced high levels of ethyl acetate (solvent-like flavor). This might be selectively counteracted by selection of an appropriate S. cerevisiae strain for the second fermentation phase, which lowers total ester profile. Hence, optimization of the process conditions and/or proper strain selection in sequentially inoculated fermentations are required to unlock the full potential for aroma improvement by the non-conventional yeast species.
Publisher: American Society for Microbiology
Date: 22-09-2022
DOI: 10.1128/AEM.00814-22
Abstract: The upscaling of fermentation to very tall cylindroconical tanks is known to negatively impact beer flavor. Most notably, the increased CO 2 pressure in such tanks compromises production by the yeast of the desirable fruity “banana” flavor (isoamyl acetate).
Start Date: 2020
End Date: 2020
Funder: Canceropôle PACA
View Funded ActivityStart Date: 2019
End Date: 2020
Funder: Fondation de France
View Funded ActivityStart Date: 2020
End Date: 2021
Funder: The European Proteomics Infrastructure Consortium providing access (EPIC-XS)
View Funded Activity