Lead toxicity in Saccharomyces cerevisiae.

Area of Science:

• Microbiology
• Environmental Toxicology
• Cell Biology

Background:

• Lead (Pb) is a toxic heavy metal with known detrimental effects on various organisms.
• Understanding the specific mechanisms of lead toxicity in model organisms like Saccharomyces cerevisiae is crucial for assessing environmental risks and developing mitigation strategies.

Purpose of the Study:

• To investigate the impact of lead (Pb) on the cell structure and function of Saccharomyces cerevisiae.
• To determine the primary cellular targets and time-dependent effects of lead exposure on yeast.

Main Methods:

• Assessing plasma membrane integrity via UV-absorbing compound release and intracellular potassium (K+) efflux.
• Evaluating cellular metabolic activity using the fluorescent probe FUN-1.
• Quantifying yeast reproductive capacity through colony-forming unit (CFU) counts.

Main Results:

• Short-term exposure (up to 30 min) to lead (Pb) at 1,000 μmol/l did not compromise plasma membrane integrity, indicated by no significant leakage of UV(260)-absorbing compounds or K+ efflux.
• Exposure for 60 min to 1,000 μmol/l Pb reduced the ability to process the FUN-1 probe but did not affect proliferation capacity.
• Prolonged exposure (120 min) to 1,000 μmol/l Pb resulted in a >50% loss of metabolic activity and replication competence.

Conclusions:

• The plasma membrane is not the immediate or primary target of lead (Pb) toxicity in Saccharomyces cerevisiae.
• Lead toxicity in yeast is time-dependent, affecting metabolic activity and replication after prolonged exposure.
• The mechanism underlying lead-induced loss of metabolic activity and replication competence likely involves protein synthesis.