Rumen Probiosis: effects of addition of yeast culture (viable yeast (Saccharomyces cerevisiae) plus growth medium) on patterns of rumen fermentation

Author(s):  
P. E. V. Williams ◽  
G. M. Innes

The use of brewery by-products which contain varying quantities of live and dead yeast cells as nitrogen supplements in diets for ruminants is well documented.There have been several recent reports of micro-organisms, previously considered as being totally aerobic, multiplying and exhibiting growth in the rumen and in rumen simulators and conferring beneficial effects on cellulolysis and growth or productive capacity of the animal. Dawson (1987) reported that certain strains of yeast (Saccharomyces cerivisae) multiplied when introduced into the rumen. Although at some point extensive lysis occurs with extrusion of the cell contents (Bruning and Yokoyama, 1988). The present experiment was carried out to assess the effects of including yeast culture (YS) (Saccharomyces cerevisae, plus growth medium: 5x106 organisms/g) in diets for ruminants. The responses in terms of effects on rumen metabolism were monitored in three cannulated steers.The aim of the experiment was to determine the effects on the rumen metabolism and the degradability of a forage using the nylon bag technique (Ørskov and McDonald, 1970) when yeast culture was added to two contrasting diets and given to young steers. The diets were either a high forage diet of hay or a mixture of forage plus concentrate given in such a manner as to induce a negative associative effect.

1978 ◽  
Vol 24 (6) ◽  
pp. 637-642 ◽  
Author(s):  
K. C. Thomas ◽  
Mary Spencer

Effects of the carbon source and oxygen on ethylene production by the yeast Saccharomyces cerevisiae have been studied. The amounts of ethylene evolved by the yeast culture were less than those detected in the blank (an equal volume of uninoculated medium), suggesting a net absorption of ethylene by the yeast cells. Addition of glucose to the lactate-grown yeast culture induced ethylene production. This glucose-induced stimulation of ethylene production was inhibited to a great extent by cycloheximide. Results suggested that the yeast cells in the presence of glucose synthesized an ethylene precursor and passed it into the medium. The conversion of this precursor to ethylene might be stimulated by oxygen. The fact that ethylene was produced by the yeast growing anaerobically and also by respiration-deficient mutants isolated from the wild-type yeast suggested that mitochondrial ATP synthesis was not an absolute requirement for ethylene biogenesis.


Author(s):  
C.J. Newbold ◽  
R.J. Wallace

The practice of adding low levels of non-commensal yeast and fungi to ruminant diets is increasingly gaining acceptance as a means of manipulating rumen fermentation to benefit production. Reported benefits include an increased degradability of forages in the rumen and an improved flow of microbial protein from the rumen (Williams and Newbold, 1990).Distillery by-products, such as pot ale syrup, are commonly included in ruminant diets as an energy source. However, pot ale syrup contains a substantial number of yeast cells. The aim of the present study was to establish if different yeasts and yeast-containing by-products had similar effects on rumen fermentation to those found with a commercial yeast culture feed additive.Two commercial Saccharomyces cerevisiae preparations (Alkosel, Alko Biotechnology, Finland and Yea-sacc, Alltech, UK), active dried baker's yeast (United Distillers, UK) and two pot ale syrups from the Inchgower and Dailuaine distilleries were compared for their effects on the fermentation in the rumen simulation technique (Rusitec).


2010 ◽  
Vol 39 (3) ◽  
pp. 447-453 ◽  
Author(s):  
André Luiz Watanabe ◽  
Elisabete Maria Macedo Viegas ◽  
Lígia Uribe Gonçalves

This study was conducted to evaluate the inclusion of two levels (2.5 e 5.0%) of dried yeast (Saccharomyces cerevisiae) and its by-products, disrupted yeast cells and yeast cell wall in diets for juveniles of pacu (Piaractus mesopotamicus). Production performance, body and plasmatic composition indexes were evaluated. Seven isoproteic (26% digestible protein) and isoenergetic (3.100 kcal digestible energy) diets were formulated containing increased levels of each ingredient. The diets were supplied for 86 days, "ad libitum". Yeast and by-products increase feed efficiency and protein use, when compared to the control diet. Carcass composition and plasmatic (glucose, cortisol, uric acid, urea and plasmatic protein) levels are not affected by the test ingredient supplementation.


2008 ◽  
Vol 3 (4) ◽  
pp. 417-421 ◽  
Author(s):  
Larisa Chaustova ◽  
Valė Miliukienė ◽  
Aurelijus Zimkus ◽  
Valdemaras Razumas

AbstractThe transformation efficiency of yeast cells during exponential growth might be characterised as undulatory. The aim of the study was to investigate the reason for the fluctuation in transformation efficiency of yeast Saccharomyces cerevisiae p63-DC5 cells during exponential growth. The heightened response to exogenous DNA was observed with the growing yeast culture when budded cells were predominant. To confirm this phenomenon we carried out synchronization of yeast cells with 10 mM hydroxyurea. Results showed that synchronous yeast cells in the S-phase of cell cycle have enhanced transformation efficiency. Furthermore, S. cerevisiae p63-DC5 cells in the S-phase were successfully transformed with plasmid pl13 in the absence of lithium acetate. We indicated that the permeability of yeast cells in the S-phase to tetraphenylphosphonium (TPP) cations was significantly higher than in asynchronous culture. The results of our study showed that the fluctuation in transformation efficiency was strictly dependent on the metabolic state of yeast cells and the capacity of the yeast cells to become competent was related to the S-phase of cell cycle.


Genetics ◽  
1996 ◽  
Vol 142 (3) ◽  
pp. 737-747 ◽  
Author(s):  
Jacques Archambault ◽  
David B Jansma ◽  
James D Friesen

Abstract In the yeast Saccharomyces cerevisiae, mutations in genes encoding subunits of RNA polymerase II (RNAPII) often give rise to a set of pleiotropic phenotypes that includes temperature sensitivity, slow growth and inositol auxotrophy. In this study, we show that these phenotypes can be brought about by a reduction in the intracellular concentration of RNAPII. Underproduction of RNAPII was achieved by expressing the gene (RPO21), encoding the largest subunit of the enzyme, from the LEU2 promoter or a weaker derivative of it, two promoters that can be repressed by the addition of leucine to the growth medium. We found that cells that underproduced RPO21 were unable to derepress fully the expression of a reporter gene under the control of the INO1 UAS. Our results indicate that temperature sensitivity, slow growth and inositol auxotrophy is a set of phenotypes that can be caused by lowering the steady-state amount of RNAPII; these results also lead to the prediction that some of the previously identified RNAPII mutations that confer this same set of phenotypes affect the assembly/stability of the enzyme. We propose a model to explain the hypersensitivity of INO1 transcription to mutations that affect components of the RNAPII transcriptional machinery.


2020 ◽  
Vol 7 (1) ◽  
pp. 6
Author(s):  
Somanon Bhattacharya ◽  
Tejas Bouklas ◽  
Bettina C. Fries

Candida albicans, Candida auris, Candida glabrata, and Cryptococcus neoformans are pathogenic yeasts which can cause systemic infections in immune-compromised as well as immune-competent individuals. These yeasts undergo replicative aging analogous to a process first described in the nonpathogenic yeast Saccharomyces cerevisiae. The hallmark of replicative aging is the asymmetric cell division of mother yeast cells that leads to the production of a phenotypically distinct daughter cell. Several techniques to study aging that have been pioneered in S. cerevisiae have been adapted to study aging in other pathogenic yeasts. The studies indicate that aging is relevant for virulence in pathogenic fungi. As the mother yeast cell progressively ages, every ensuing asymmetric cell division leads to striking phenotypic changes, which results in increased antifungal and antiphagocytic resistance. This review summarizes the various techniques that are used to study replicative aging in pathogenic fungi along with their limitations. Additionally, the review summarizes some key phenotypic variations that have been identified and are associated with changes in virulence or resistance and thus promote persistence of older cells.


Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 850
Author(s):  
Karolina Nowosad ◽  
Monika Sujka ◽  
Urszula Pankiewicz ◽  
Damijan Miklavčič ◽  
Marta Arczewska

The aim of the study was to investigate the influence of a pulsed electric field (PEF) on the level of iron ion accumulation in Saccharomyces cerevisiae cells and to select PEF conditions optimal for the highest uptake of this element. Iron ions were accumulated most efficiently when their source was iron (III) nitrate. When the following conditions of PEF treatment were used: voltage 1500 V, pulse width 10 μs, treatment time 20 min, and a number of pulses 1200, accumulation of iron ions in the cells from a 20 h-culture reached a maximum value of 48.01 mg/g dry mass. Application of the optimal PEF conditions thus increased iron accumulation in cells by 157% as compared to the sample enriched with iron without PEF. The second derivative of the FTIR spectra of iron-loaded and -unloaded yeast cells allowed us to determine the functional groups which may be involved in metal ion binding. The exposure of cells to PEF treatment only slightly influenced the biomass and cell viability. However, iron-enriched yeast (both with or without PEF) showed lower fermentative activity than a control sample. Thus obtained yeast biomass containing a high amount of incorporated iron may serve as an alternative to pharmacological supplementation in the state of iron deficiency.


Genetics ◽  
1987 ◽  
Vol 116 (4) ◽  
pp. 531-540
Author(s):  
Aileen K W Taguchi ◽  
Elton T Young

ABSTRACT The alcohol dehydrogenase II (ADH2) gene of the yeast, Saccharomyces cerevisiae, is not transcribed during growth on fermentable carbon sources such as glucose. Growth of yeast cells in a medium containing only nonfermentable carbon sources leads to a marked increase or derepression of ADH2 expression. The recessive mutation, adr6-1, leads to an inability to fully derepress ADH2 expression and to an inability to sporulate. The ADR6 gene product appears to act directly or indirectly on ADH2 sequences 3' to or including the presumptive TATAA box. The upstream activating sequence (UAS) located 5' to the TATAA box is not required for the Adr6- phenotype. Here, we describe the isolation of a recombinant plasmid containing the wild-type ADR6 gene. ADR6 codes for a 4.4-kb RNA which is present during growth both on glucose and on nonfermentable carbon sources. Disruption of the ADR6 transcription unit led to viable cells with decreased ADHII activity and an inability to sporulate. This indicates that both phenotypes result from mutations within a single gene and that the adr6-1 allele was representative of mutations at this locus. The ADR6 gene mapped to the left arm of chromosome XVI at a site 18 centimorgans from the centromere.


1989 ◽  
Vol 9 (2) ◽  
pp. 442-451
Author(s):  
M Nishizawa ◽  
R Araki ◽  
Y Teranishi

To clarify carbon source-dependent control of the glycolytic pathway in the yeast Saccharomyces cerevisiae, we have initiated a study of transcriptional regulation of the pyruvate kinase gene (PYK). By deletion analysis of the 5'-noncoding region of the PYK gene, we have identified an upstream activating sequence (UASPYK1) located between 634 and 653 nucleotides upstream of the initiating ATG codon. The promoter activity of the PYK 5'-noncoding region was abolished when the sequence containing the UASPYK1 was deleted from the region. Synthetic UASPYK1 (26mer), in either orientation, was able to restore the transcriptional activity of UAS-depleted mutants when placed upstream of the TATA sequence located at -199 (ATG as +1). While the UASPYK1 was required for basal to intermediate levels of transcriptional activation, a sequence between -714 and -811 was found to be necessary for full activation. On the other hand, a sequence between -344 and -468 was found to be responsible for transcriptional repression of the PYK gene when yeast cells were grown on nonfermentable carbon sources. This upstream repressible sequence also repressed transcription, although to a lesser extent, when glucose was present in the medium. The possible mechanism for carbon source-dependent regulation of PYK expression through these cis-acting regulatory elements is discussed.


1987 ◽  
Vol 7 (10) ◽  
pp. 3799-3805
Author(s):  
P J Schatz ◽  
G E Georges ◽  
F Solomon ◽  
D Botstein

Microtubules in yeasts are essential components of the mitotic and meiotic spindle and are necessary for nuclear movement during cell division and mating. The yeast Saccharomyces cerevisiae has two alpha-tubulin genes, TUB1 and TUB3, either of which alone is sufficient for these processes when present in a high enough copy number. Comparisons of sequences from several species reveals the presence of a variable region near the amino terminus of alpha-tubulin proteins. We perturbed the structure of this region in TUB3 by inserting into it 3, 9, or 17 amino acids and tested the ability of these altered proteins to function as the only alpha-tubulin protein in yeast cells. We found that each of these altered proteins was sufficient on its own for mitotic growth, mating, and methods of yeast. We conclude that this region can tolerate considerable variation without losing any of the highly conserved functions of alpha-tubulin. Our results suggest that variability in this region occurs because it can be tolerated, not because it specifies an important function for the protein.


Sign in / Sign up

Export Citation Format

Share Document