scholarly journals Metabolic Response of the Yeast Candida utilis During Enrichment in Selenium

2020 ◽  
Vol 21 (15) ◽  
pp. 5287 ◽  
Author(s):  
Marek Kieliszek ◽  
Katarzyna Bierla ◽  
Javier Jiménez-Lamana ◽  
Anna Maria Kot ◽  
Jaime Alcántara-Durán ◽  
...  
Keyword(s):  
Candida Utilis ◽  
Metabolic Response ◽  
Thioredoxin Reductase ◽  
Dry Weight ◽  
Yeast Cells ◽  
Insoluble Protein ◽  
Glutathione S Transferase ◽  
Response To Stress ◽  
Insoluble Protein Fraction ◽  
Orbitrap Ms

Selenium (Se) was found to inhibit the growth of the yeast Candida utilis ATCC 9950. Cells cultured in 30 mg selenite/L supplemented medium could bind 1368 µg Se/g of dry weight in their structures. Increased accumulation of trehalose and glycogen was observed, which indicated cell response to stress conditions. The activity of antioxidative enzymes (glutathione peroxidase, glutathione reductase, thioredoxin reductase, and glutathione S-transferase) was significantly higher than that of the control without Se addition. Most Se was bound to water-insoluble protein fraction; in addition, the yeast produced 20–30 nm Se nanoparticles (SeNPs). Part of Se was metabolized to selenomethionine (10%) and selenocysteine (20%). The HPLC-ESI-Orbitrap MS analysis showed the presence of five Se compounds combined with glutathione in the yeast. The obtained results form the basis for further research on the mechanisms of Se metabolism in yeast cells.

scholarly journals Accumulation of Selenium in Candida utilis Growing in Media of Increasing Concentration of this Element

2020 ◽  
Vol 10 (4) ◽  
pp. 1439 ◽  
Author(s):  
Marek Kieliszek ◽  
Anna Maria Kot ◽  
Kamil Piwowarek ◽  
Stanisław Błażejak
Keyword(s):  
Candida Utilis ◽  
Culture Medium ◽  
Dry Weight ◽  
Yeast Cells ◽  
Reciprocating Motion ◽  
Experimental Medium ◽  
Yeast Cultures ◽  
Cell Biomass ◽  
Icp Ms ◽  
Living Organisms

Selenium is considered an essential component of all living organisms. Studies on the enrichment of yeast cells with selenium, using the ability of cell biomass to bind this element, are being reported more and more. Yeast cultures were cultivated in YPD medium enriched with Na2SeO3 salts for 72 h at 28 °C on a shaker utilizing reciprocating motion. Selenium in cell biomass was determined with the use of ICP–MS. It was observed that the addition of selenium to the experimental medium (in the range of 4–100 mg/L) increased the content of this element in the yeast cell biomass. During the extension of cultivation time, the number of yeast cells and biomass yield exhibited a decreasing trend. Based on the obtained results, it was concluded that yeast cells exhibited the ability to accumulate selenium in both logarithmic and stationary growth phases. The dose of 20 and 30 mg/L of selenium in the culture medium meets the expectations in terms of both the content of selenium bound to yeast cells (1944 ± 110.8 μg/g dry weight) under 48-h cultivation. The obtained results confirmed that the Candida utilis ATCC 9950 strain exhibits the ability to bind selenium, which means that the biomass of these yeasts may be used as a natural source of selenium in the diet of humans and animals.

scholarly journals Speciation Analysis of Selenium in Candida utilis Yeast Cells Using HPLC-ICP-MS and UHPLC-ESI-Orbitrap MS Techniques

2018 ◽  
Vol 8 (11) ◽  
pp. 2050 ◽  
Author(s):  
Marek Kieliszek ◽  
Stanisław Błażejak
Keyword(s):  
Candida Utilis ◽  
Speciation Analysis ◽  
Yeast Cells ◽  
Future Research ◽  
Selenium Compounds ◽  
Icp Ms ◽  
Inorganic Selenium ◽  
Low Mass ◽  
Living Organisms ◽  
Orbitrap Ms

Selenium plays a key role in the proper metabolism of living organisms. The search for new selenium compounds opens up new possibilities for understanding selenometabolome in yeast cells. This study was aimed at the identification of compounds containing selenium in the feed yeasts Candida utilis ATCC 9950. Yeast biomass was kept in aqueous solutions enriched with inorganic selenium (20 mg·L−1) for 24 h. Speciation analysis of the element was performed using the HPLC-ICP-MS and UHPLC-ESI-Orbitrap MS techniques. The obtained selenium value in the yeast was 629 μg·g−1, while the selenomethionine value was 31.57 μg·g−1. The UHPLC-ESI-Orbitrap MS analysis conducted allowed for the identification of six selenium compounds: dehydro-selenomethionine-oxide, selenomethionine, selenomethionine-NH3, a Se-S conjugate of selenoglutathione-cysteine, methylthioselenoglutathione, and 2,3-DHP-selenocysteine-cysteine. In order to explain the structure of selenium compounds, the selected ions were subjected to fragmentation. The selenium compounds obtained with a low mass play a significant role in the metabolism of the compound. However, the bioavailability of such components and their properties have not been fully understood. The number of signals indicating the presence of selenium compounds obtained using the UHPLC-ESI-Orbitrap MS method was characterized by higher sensitivity than when using the HPLC-ICP-MS method. The obtained results will expand upon knowledge about the biotransformation of selenium in eukaryotic yeast cells. Future research should focus on understanding the entire selenium metabolism in cells and on the search for new transformation pathways for this element. This opens up new possibilities for obtaining functional food, rich in easily absorbable selenium sources, and constituting an alternative to dietary supplements based on this compound found primarily in inorganic form.

Heterogeneity of Size and Distribution of Intramembrane Particles in the Plasma Membrane of Yeast

1977 ◽  
Vol 35 ◽  
pp. 596-597
Author(s):  
E. Keyhani
Keyword(s):  
Plasma Membrane ◽  
Candida Utilis ◽  
Synthetic Medium ◽  
Freeze Fracture ◽  
Translational Diffusion ◽  
Yeast Cells ◽  
Distilled Water ◽  
Intramembrane Particles ◽  
The Matrix ◽  
Water Cell

The matrix of biological membranes consists of a lipid bilayer into which proteins or protein aggregates are intercalated. Freeze-fracture techni- ques permit these proteins, perhaps in association with lipids, to be visualized in the hydrophobic regions of the membrane. Thus, numerous intramembrane particles (IMP) have been found on the fracture faces of membranes from a wide variety of cells (1-3). A recognized property of IMP is their tendency to form aggregates in response to changes in experi- mental conditions (4,5), perhaps as a result of translational diffusion through the viscous plane of the membrane. The purpose of this communica- tion is to describe the distribution and size of IMP in the plasma membrane of yeast (Candida utilis).Yeast cells (ATCC 8205) were grown in synthetic medium (6), and then harvested after 16 hours of culture, and washed twice in distilled water. Cell pellets were suspended in growth medium supplemented with 30% glycerol and incubated for 30 minutes at 0°C, centrifuged, and prepared for freeze-fracture, as described earlier (2,3).

scholarly journals Racemization of tyrosine in the insoluble protein fraction of brunescent aging human lenses.

1994 ◽  
Vol 269 (36) ◽  
pp. 22678-22682
Author(s):  
M. Luthra ◽  
D. Ranganathan ◽  
S. Ranganathan ◽  
D. Balasubramanian
Keyword(s):  
Protein Fraction ◽  
Insoluble Protein ◽  
Human Lenses ◽  
Insoluble Protein Fraction

A system model of the metabolic response to stress

1983 ◽  
Vol 28 (4) ◽  
pp. 268-273 ◽  
Author(s):  
Carta Atkinson ◽  
John H. Milsum
Keyword(s):  
Metabolic Response ◽  
System Model ◽  
Response To Stress

scholarly journals Growth performance and metabolic response of Nile tilapia fed rations supplemented with autolized yeast and zinc

2010 ◽  
Vol 39 (12) ◽  
pp. 2560-2568 ◽  
Author(s):  
Altevir Signor ◽  
Luiz Edivaldo Pezzato ◽  
Pedro de Magalhães Padilha ◽  
Carlos Roberto Padovani ◽  
Margarida Maria Barros
Keyword(s):  
Alkaline Phosphatase ◽  
Growth Performance ◽  
Nile Tilapia ◽  
Metabolic Response ◽  
Mineral Metabolism ◽  
Dry Weight ◽  
Ammonia Concentration ◽  
Metabolic Responses ◽  
Feed Conversion ◽  
Kinetic Activity

This research evaluated the influence of yeast and zinc on growth performance and metabolic responses of Nile tilapia. Diets were formulated to contain 32.0% digestible protein and 3,240 kcal DE/kg diet and the following autolized yeast (%):zinc (mg/kg)relationships: 0.0:0.0; 0.0:79.5; 2.0:0.0; 0.795:79.5; 2.0:200; 4.0:400; 6.0:600; 12.0:1,200 and 14.0:1,400. It was used 135 fingerlings (7.27 ± 0.19 g), distributed in a complete random design in 27 50-L aquaria and they were fed ad libitum four times a day for 128 days. It was evaluated growth performance and metabolic responses, weight gain, apparent feed conversion; protein efficiency and survival rate; percentage of protein, ether extract, dry weight and ashes in the muscle and in the bones; ammonia concentration and kinetic activity of alkaline phosphatase in the liver; ammonia, kinetic activity of alkaline phosphatase, urea and lipids in the plasma and; minerals in plasma, in the liver and in the bones of the fish. High levels of yeast and zinc in the diet impaired growth performance and metabolic responses of the fish. Autolized yeast at the level of 2.0% determines the best growth performance. Levels higher than 6.0% of autolized yeast and 600 mg zinc in the diets impair growth performance and lipid metabolism in fish and levels higher than 4.0% of autolized yeast and 400 mg zinc/kg in the diet impair mineral metabolism.

Metabolic Response to Stress

2005 ◽  
pp. 3-13 ◽  
Author(s):  
Maria Isabel Toulson Davisson Correia ◽  
Carolina Trancoso de Almeida
Keyword(s):  
Metabolic Response ◽  
Response To Stress

scholarly journals Threonine Overproduction in Yeast Strains Carrying theHOM3-R2 Mutant Allele under the Control of Different Inducible Promoters

1999 ◽  
Vol 65 (1) ◽  
pp. 110-116 ◽  
Author(s):  
María-José Farfán ◽  
Luis Aparicio ◽  
Isabel L. Calderón
Keyword(s):  
Mutant Allele ◽  
Metabolic Flux ◽  
Dry Weight ◽  
Yeast Cells ◽  
Aspartate Kinase ◽  
Inducible Promoters ◽  
Yeast Strains ◽  
Threonine Production ◽  
Amino Acid Contents ◽  
Serine Deaminase

ABSTRACT The HOM3 gene of Saccharomyces cerevisiaecodes for aspartate kinase, which plays a crucial role in the regulation of the metabolic flux that leads to threonine biosynthesis. With the aim of obtaining yeast strains able to overproduce threonine in a controlled way, we have placed the HOM3-R2 mutant allele, which causes expression of a feedback-insensitive enzyme, under the control of four distinctive regulatable yeast promoters, namely, P GAL1 , P CHA1 , P CYC1-HSE2 , and P GPH1 . The amino acid contents of strains bearing the different constructs were analyzed both under repression and induction conditions. Although some differences in overall threonine production were found, a maximum of around 400 nmol/mg (dry weight) was observed. Other factors, such as excretion to the medium and activity of the catabolic threonine/serine deaminase, also affect threonine accumulation. Thus, improvement of threonine productivity by yeast cells would probably require manipulation of these and other factors.

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