Yeast stress

Davies, J. M. S., Lowry, C. V., Davies, K J. A (1995). Transcient adaptation to oxidative stressing yeast. Archives of Biochemistry... 

The fermentation in these big vessels (max 3—5 brews) is normally performed pressureless, but several investigations have been made on fermentation under pressure and using somewhat higher temperatures in order to reduce the time needed still further. Some brewers agree with the statement that no yeast yet known can tolerate this extra stress and at the same time ferment a beet of equivalent excellent quaUty, but new selected yeast strains (genetic engineering) in the future may be better suited to these conditions. 

The distribution of elements in single-cell non-photosynthetic eukaryotes is probably best seen in terms of the well-defined compartments of yeast. The central cytoplasmic compartment containing the nucleus has many free element concentrations, only somewhat different from those in all known aerobic prokaryotes (Figure 7.7). (The nuclear membrane is a poor barrier to small molecules and ions and so we include the nucleus with the cytoplasm.) We do not believe in fact that the free cytoplasmic values of Mg2+, Mn2+, Fe2+, Ca2+, and possibly Zn2+, have changed greatly throughout evolution. As stressed already there are limitations since free Mg2+ and Fe2+ are essential for the maintenance of the primary synthetic routes of all cells, and changes in other free metal ions could well have imposed... 

However, in case of acute clinical mastitis, it is widely accepted that animal welfare considerations should take prevalence. If both farmer and veterinarian are not familiar with non-antibiotic treatments, they should be advised to use broad-spectrum antibiotics immediately, because any delay (e.g. the 2-3 days it often takes between diagnosis and the return of microbiological test results) may seriously harm the animal. This approach should, however, only be taken after a sound clinical diagnosis, since antibiotic treatments themselves may lead to dramatic aggravation of the condition. For example, E. coli inflammations are able to develop into severe toxaemia, because increased levels of toxins are released into the animal tissues when E. coli cells are killed or stressed by antibiotic treatments. Also, if yeasts are the main cause or form part of the pathogen complex that causes mastitis, their growth and proliferation may be supported by the administration of anti-bacterial antibiotics (Crawshaw et al., 2005). 

Piper, P., Calderon, C.O., Hatzixanthis, K. and Mollapour, M. (2001) Weak acid adaptation the stress response that confers yeasts with resistance to organic acid food preservatives . 

Li, J., Steen, H., and Gygi, S.P. (2003) Protein profiling with cleavable isotope-coded affinity tag (cICAT) reagents. The yeast salinity stress response. Mol. Cell. Proteomics 2, 1198-1204. 

A second family of MAPKs is referred to as stress-activated protein kinases (SAPKs) [3,14,15]. This includes JNKs, or Jun kinases, named originally for their phosphorylation of the transcription factor c-Jun. SAPKs were first identified in peripheral tissues on the basis of their activation in response to cellular forms of stress, which include X-ray irradiation and osmotic stress. More recently, they have been demonstrated to be activated in brain by several cytokines as well as by synaptic activity [16]. As shown in Figure 23-3, SAPKs are activated by SAPK kinases (SEKs), which are in turn activated by SEK kinases. The Ras-like small G proteins implicated in SEK kinase activation are Rac and Cdc-42. In this case, it appears that Rac/Cdc-42 triggers activation of SEK kinase by stimulating its phosphorylation by still another protein kinase termed p21-activated kinase (PAK). Thus, PAK can be considered a MAPK kinase kinase kinase, which is analogous to the cascade of protein kinases found in yeast (Fig. 23-4). 

Domain present in yeast cell wall integrity and stress response component proteins Domain with 2 conserved Trp (W) residues f3/y crystallins A20-like zinc fingers ANl-like zinc finger... 

When in later years Krebs reviewed the major points which had to be established if the cycle was to be shown to be operative in cells, the obvious needs were to find the presence of the required enzymes and to detect their substrates. As the substrates are present in the cycle in catalytic amounts their accumulation required the use of inhibitors. Krebs also stressed that rates of oxidation of the individual substrates must be at least as fast as the established rates of oxygen uptake in vivo, an argument first used by Slator (1907) with reference to fermentation A postulated intermediate must be fermented at least as rapidly as glucose is. (See Holmes, 1991). This requirement did not always appear to be met. In the early 1950s there were reports that acetate was oxidized by fresh yeast appreciably more slowly than the overall rate of yeast respiration. It was soon observed that if acetone-dried or freeze-dried yeasts were used in place of fresh yeast, rates of acetate oxidation were increased more than enough to meet the criterion. Acetate could not penetrate fresh yeast cell walls sufficiently rapidly to maintain maximum rates of respiration. If the cell walls were disrupted by drying this limitation was overcome, i.e. if rates of reaction are to be... 

J. A., Saidowsky, j., Eschee, C., and Wole, D. H. Proteinase yscE, the yeast proteasome/multicatalytic-multifunc-tional proteinase mutants unravel its function in stress induced proteolysis and uncover its necessity for cell survival. EMBO J. 1991, 30, 555-62. 

Finley, D., Ozkaynak, E., and Varshavsky, A. The yeast polyubiq-uitin gene is essential for resistance to high temperatures, starvation, and other stresses, Cell, 1987, 48, 1035-46. 

Urml Ahpl Stress, invasive growth (yeast)... 

Suml, a component of the fission yeast eIE3 translation initiation complex, is rapidly relocalized during environmental stress and interacts with components of the 26S proteasome. Mol. Biol. Cell 2002, 13, 1626-1640. 

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