Basic investigations in Saccharomyces cerevisiae.

This chapter aims to provide the reader with a one-stop reference to the basic procedures needed to access, grow, store, mate, and sporulate yeast cells. It starts with an introduction to the Web-based yeast resources, which are becoming increasingly important in the investigation of S. cerevisiae in the post-genomic era.

Differential effects of hydrogen peroxide and ascorbic acid on the aerobic thermosensitivity of yeast cells grown under aerobic and anoxic conditions.

We have previously demonstrated that in aerobically-grown cells of the yeast Saccharomyces cerevisiae, hydrogen peroxide (H(2)O(2)) increases and ascorbic acid decreases cellular thermosensitivity, as determined by the inducibility of a heat shock (HS)-reporter gene. In this work, we reveal that the aerobic thermosensitivity of anaerobically-grown yeast cells also increases in the presence of H(2)O(2), albeit differentially between cells with two different lipid profiles. In comparison to aerobically-grown fermenting cells treated with the same H(2)O(2) concentration, both these types of anaerobically-grown cells were found to be considerably less sensitive to aerobic heat shock and considerably more thermotolerant.

Can the different heat shock response thresholds found in fermenting and respiring yeast cells be attributed to their differential redox states?

In this study we used a heat-shock (HS) reporter gene to demonstrate that respiring cells are intrinsically less sensitive (by 5 degrees C) than their fermenting counterparts to a sublethal heat shock. We also used an oxidant-sensitive fluorescent probe to demonstrate that this correlates with lower levels of sublethal reactive oxygen species (ROS) accumulation in heat-stressed respiring cells. Moreover, this relationship between HS induction of the reporter gene and ROS accumulation extends to respiring cells that have had their ROS levels modified by treatment with the anti-oxidant ascorbic acid and the pro-oxidant H(2)O(2).

Basic investigations in Saccharomyces cerevisiae.

This chapter aims to provide the reader with a one-stop reference to the basic procedures needed to grow, store, mate, and sporulate yeast cells. Starting with recipes for the different types of media, the chapter then goes on to explain how cells are grown to the appropriate cell numbers at the correct stage in the growth cycle. It also provides a detailed explanation on both short- and long-term storage of yeast cells.

Reactive oxygen species may influence the heat shock response and stress tolerance in the yeast Saccharomyces cerevisiae.

Moderate levels of reactive oxygen species (ROS) have been implicated as second messengers in a number of biochemical pathways, and in animal cells have been associated with the activation of the heat shock response (HSR). Here, using an intracellular probe, we demonstrate that differential accumulation of ROS in the yeast Saccharomyces cerevisiae is strongly associated with differential induction of an HS reporter gene over a range of heat shock temperatures. There was a good correlation between cellular ROS levels and the levels of HS-induced reporter gene expression between 37 degrees C and 44 degrees C, both reaching maximal values at 41 degrees C.

The inhibition of long-term potentiation in the rat dentate gyrus by pro-inflammatory cytokines is attenuated in the presence of nicotine.

Nicotine has previously been shown to affect both long-term potentiation (LTP) and long-term depression and to reverse age-related impairments of LTP in the hippocampus. Levels of proinflammatory cytokines are known to be elevated with age and to inhibit LTP. In the present study we have investigated the effects of three pro-inflammatory cytokines on nicotine-enhanced LTP in the rat hippocampus in vitro.