Search results for "fermentation"
showing 10 items of 746 documents
Mitochondrial inheritance and fermentative : oxidative balance in hybrids between Saccharomyces cerevisiae and Saccharomyces uvarum.
2008
Breeding between Saccharomyces species is a useful tool for obtaining improved wine yeast strains, combining fermentative features of parental species. In this work, 25 artificial Saccharomyces cerevisiae × Saccharomyces uvarum hybrids were constructed by spore conjugation. A multi-locus PCR‐restriction fragment length polymorphism (PCR‐RFLP) analysis, targeting six nuclear gene markers and the ribosomal region including the 5.8S rRNA gene and the two internal transcribed spacers, showed that the hybrid genome is the result of two chromosome sets, one coming from S. cerevisiae and the other from S. uvarum. Mitochondrial DNA (mtDNA) typing showed uniparental inheritance in all hybrids. Furth…
Mitochondria inheritance is a key factor for tolerance to dehydration in wine yeast production
2015
UNLABELLED Mitochondria are the cell's powerhouse when organisms are grown in the presence of oxygen. They are also the source of reactive oxygen species that cause damage to the biochemical components of the cell and lead to cellular ageing and death. Under winemaking conditions, Saccharomyces yeasts exclusively have a fermentative metabolism due to the high sugar content of grape must. However, their production as an active dry yeast (ADY) form required aerobic propagation and a dehydration process. In these industrial steps, oxidative stress is particularly harmful for the cell. In this work, we analysed the impact of the mitochondrial genome on oxidative stress response, longevity and d…
Yeast Translation Elongation Factor eIF5A Expression Is Regulated by Nutrient Availability through Different Signalling Pathways
2020
Translation elongation factor eIF5A binds to ribosomes to promote peptide bonds between problematic amino acids for the reaction like prolines. eIF5A is highly conserved and essential in eukaryotes, which usually contain two similar but differentially expressed paralogue genes. The human eIF5A-1 isoform is abundant and implicated in some cancer types
Mitotic Recombination and Genetic Changes in Saccharomyces cerevisiae during Wine Fermentation
2000
Natural strains of Saccharomyces cerevisiae are prototrophic homothallic yeasts that sporulate poorly, are often heterozygous, and may be aneuploid. This genomic constitution may confer selective advantages in some environments. Different mechanisms of recombination, such as meiosis or mitotic rearrangement of chromosomes, have been proposed for wine strains. We studied the stability of the URA3 locus of a URA3/ura3 wine yeast in consecutive grape must fermentations. ura3/ura3 homozygotes were detected at a rate of 1 x 10(-5) to 3 x 10(-5) per generation, and mitotic rearrangements for chromosomes VIII and XII appeared after 30 mitotic divisions. We used the karyotype as a meiotic marker an…
Polyketide Derivatives from Mangrove Derived Endophytic Fungus Pseudopestalotiopsis theae
2020
Chemical investigation of secondary metabolites from the endophytic fungus Pseudopestalotiopsis theae led to the isolation of eighteen new polyketide derivatives, pestalotheols I&ndash
Lactobacillus bobalius sp. nov., a lactic acid bacterium isolated from Spanish Bobal grape must
2008
A Lactobacillus strain, designated 203(T), previously isolated from Bobal grape must was characterized phylogenetically, genotypically and phenotypically in order to establish whether it represents a novel species. On the basis of the 16S rRNA gene sequence, strain 203(T) was shown to belong to the genus Lactobacillus, falling within the Lactobacillus alimentarius-Lactobacillus farciminis group and being closely related to the type strains of L. alimentarius, Lactobacillus kimchii and Lactobacillus paralimentarius. DNA-DNA hybridization results confirmed the separate status of strain 203(T) at the species level. To establish the similarities and differences between 203(T) and the three afor…
A Na+-coupled C4-dicarboxylate transporter (Asuc_0304) and aerobic growth of Actinobacillus succinogenes on C4-dicarboxylates
2014
Actinobacillus succinogenes, which is known to produce large amounts of succinate during fermentation of hexoses, was able to grow on C4-dicarboxylates such as fumarate under aerobic and anaerobic conditions. Anaerobic growth on fumarate was stimulated by glycerol and the major product was succinate, indicating the involvement of fumarate respiration similar to succinate production from glucose. The aerobic growth on C4-dicarboxylates and the transport proteins involved were studied. Fumarate was oxidized to acetate. The genome of A. succinogenes encodes six proteins with similarity to secondary C4-dicarboxylate transporters, including transporters of the Dcu (C4-dicarboxylate uptake), Dcu…
Factors affecting physiology of mycelial growth and mushrooms aroma production in solid state fermentation
1997
L'effet de différentes sources d'azote et du rapport C/N sur la croissance mycélienne et sur l'intensité aromatique dégagée par trois espèces du genre #Morchella$ et d'une espèce du genre #Pleurotus$ a été étudié sur agar puis sur support solide. Les résultats ont été à la base du choix du nitrate de sodium comme source d'azote, du rapport C/N de 10 ainsi que du mycélium de #M. esculenta$ come source potentielle pour la production de l'arôme de morille. L'identification des molécules contribuant à l'arôme réalisée par CPG-SM a révélé de larges différences entre #M. esculenta$ et #P. cornucopiae$. Dans la mesure où l'arôme produit par le mycélium rappelle celui du carpophore, ce résultat con…
A selective medium for the isolation of malolactic mutants of Leuconostoc oenos
1994
We have developed a selective medium for the isolation of Leuconostoc oenos mutants defective in malolactic fermentation. Forty per cent of colonies isolated directly on selective plates after UV mutagenesis had lost their ability to degrade malate. None of the tested mutants showed any detectable malolactic activity and all lacked a protein band corresponding in size to that of the malolactic enzyme. The availability of such mutants provides a valuable tool both for physiological and genetic research on malolactic fermentation.
Induction of ambuic acid derivatives by the endophytic fungus Pestalotiopsis lespedezae through an OSMAC approach
2021
Abstract Ten new ambuic acid derivatives, pestallic acids H–Q including one new iodinated natural product along with two known compounds, ambuic acid and ambuic acid 18-acetate, were obtained through fermentation of the endophytic fungus Pestalotiopsis lespedezae on solid rice medium with 3.5% NaI. Pestallic acids H–Q were undetectable in cultures of the fungus grown on solid rice medium lacking NaI or in those where NaI had been replaced by NaCl or NaBr. The structures of the new metabolites were established on basis of 1D/2D NMR and HRESIMS data. Their absolute configurations were determined by Mosher’s method and TDDFT-ECD calculations. The compounds failed to show antibacterial activity…