A proteome analysis of the yeast response to the herbicide 2,4-dichlorophenoxyacetic acid

Abstract

The intensive use of herbicides may give rise to a number of toxicological problems in non-target organisms and has led to the emergence of resistant weeds. To gain insights into the mechanisms of adaptation to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), we have identified variations in protein expression level in the eukaryotic experimental model Saccharomyces cerevisiae exposed to herbicide aggression, based on two-dimensional gel electrophoresis. We show results suggesting that during the adaptation period preceding the resumption of inhibited exponential growth under herbicide stress, the antioxidant enzyme Ahp1p and the heat shock proteins Hsp12p and Ssb2p (or Ssb1p) are present in higher amounts. The increased level of other enzymes involved in protein (Cdc48p) and mRNA (Dcp1p) degradation, in carbohydrate metabolism (Eno1p, Eno2p and Glk1p) and in vacuolar H(+)-ATPase (V-ATPase) function (Vma1p and Vma2p, two subunits of the peripheral catalytic sector) was also registered. V-ATPase is involved in the homeostasis of intracellular pH and in the compartmentalization of amino acids and other metabolites in the vacuole. The increased expression of amino acid biosynthetic enzymes (Arg1p, Aro3p, Aro8p, Gdh1p, His4p, Ilv3p and Met6p), also suggested by comparative analysis of the proteome, was correlated with the reduction of amino acid concentration registered in both the vacuole and the cytosol of 2,4-D-stressed cells, possibly due to the disturbance of vacuolar and plasma membrane functions by the lipophilic acid herbicide.

Inhibitory activity of blasticidin A, a strong aflatoxin production inhibitor, on protein synthesis of yeast: selective inhibition of aflatoxin production by protein synthesis inhibitors

“…There are many works on proteome of S. cerevisiae 12 and alterations in protein abundance levels can provide clues about the mechanism of action of various drugs. 13 However, it is still difficult to estimate the target molecule of a drug from proteome information alone. In this study, we found relationship between protein synthesis inhibition and decrease of abundances of ribosomal proteins in S. cerevisiae.…”

Teaching expression proteomics: From the wet‐lab to the laptop

“…Examples include case-studies based on our own experience in using Expression Proteomics to get mechanistic insights into the response and resistance to chemical stress resistance in two microbial model systems: the yeast Saccharomyces cerevisiae [19,20] and bacteria of Pseudomonas species [21,22]. One of these case-studies is then used as the basis for the laboratory and computational classes.…”

“…This curricular unit is a mandatory discipline for around 60 students per year, as part of the Biological Engineering (40) or Biotechnology (20) curricula. These students, together with others that annually choose the discipline as an option, attend the theoretical classes and are divided in groups of 15 for computational and, when available, of 12 for wet laboratory classes.…”

Oxidative Stress Induced by the 2,4-Dichlorophenoxyacetic Herbicide

“…The global yeast response to 2,4-D, revealed by microarray and proteomic analyses, indicates the upregulation of a large number of genes involved in alternative carbon and nitrogen source metabolism (Teixeira et al, 2006a) and in the uptake and biosynthesis of amino acids (Teixeira et al, 2006a;Teixeira et al, 2005), correlating with a dramatic reduction of the intracellular concentration of amino acids (Teixeira et al, 2005). These adaptive mechanisms might be a response to the deleterious effects exerted by 2,4-D on plasma membrane lipid organization and permeability, leading to nutrient import inhibition (Bradberry et al, 2000) (Figure 2).…”