The SED1 gene (YDR077W), coding for the major cell wall glycoprotein of Saccharomyces cerevisiae stationary-phase cells, contains two blocks of tandem repeat units located within two distinct regions of the nucleotide sequence. A PCR survey of the SED1 open reading frames (ORFs) of 186 previously uncharacterized grape must isolates of S. cerevisiae yielded 13 PCR profiles arising from different combinations of seven SED1 length variants in individuals homozygous or heterozygous for the gene. Comparison of the nucleotide sequences of a group of representatives of each of the seven length variants with those of S288C and the type strain, CBS1171, unequivocally identified them as SED1 alleles and provided evidence for the presence of two minisatellite-like sequences, variable in length, within the ORF of an S. cerevisiae gene. The segregation analyses of the SED1 length variants and other genetic markers in 13 isolates representative of each PCR profile suggested that molecular mechanisms involved in minisatellite expansion and contraction may be responsible for SED1 heterozygosities within a population of homothallic must isolates of S. cerevisiae. SED1 (YDR077W), initially identified as a multicopy suppressor of the ERD2 deletion (15), has more recently been shown to encode the most abundant cell wall glycoprotein of Saccharomyces cerevisiae stationary-phase cells (28). Sed1p is rich in serines and threonines and, like other cell wall proteins, has N-and C-terminal hydrophobic domains, multiple sites for glycosylation with both N-and O-linked sugars, and a signal sequence for the addition of a glycosylphosphatidylinositol anchor at the carboxy terminus (6, 13, 14). Sed1p is not essential for normal growth (15, 28). However, a SED1 deletion results in decreased resistance to the action of zymolyase with respect to wild-type cells (28). This phenotype is more evident in stationary-phase cells, implicating the involvement of Sed1p in stress resistance during that growth phase. SED1 is strongly up-regulated at the diauxic shift upon glucose depletion (9) and is highly expressed around the M phase of the cell cycle (7,29) and in the presence of aluminum and zinc (11). The presence of both stress-responsive elements (CCCCT and AGGGG) in the promoter and upstream region of the gene (28) and of three putative PEST regions (8), which may be necessary for rapid changes in concentration of the protein in response to environmental stimuli (24, 25), has suggested a role for Sed1p in providing resistance to biotic and abiotic stresses.Analysis of the amino acid sequence of Sed1p in S. cerevisiae S288C revealed the presence of repeated amino acid motifs localized within two distinct regions of the polypeptide chain (15). Based on the SED1 nucleotide sequence of S288C, the first region (region 1) contains three repeat units of 66 bp and a truncated one of 42 bp arranged in the following order: 66, 42, 66, 66. The penultimate codon of each 66-bp unit encodes an asparagine residue that is a potential N-linked glycosylation site. T...

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In recent years, the use of glyphosate has dramatically increased worldwide, and there is growing concern about contamination of organic products caused by its heavy use on neighboring fields. Glyphosate is found as a residue not only in soil, plants, and groundwater but also in humans and animals. Considering the controversy on glyphosate maximum residue level in foodstuff and the difficulties in its analytical determination, the main purpose of the present paper was to investigate the competence and accuracy of 13 accredited European laboratories in determining glyphosate in wheat flour at a level close to their reporting limit of 10 μg/kg. According to the results of this performance assessment, the laboratories were not able to quantify glyphosate at trace levels. Therefore, their specified reporting limits of 10 μg/kg were not supported by their results, and a reporting limit of around 50 μg/kg of glyphosate in flour seems to be more appropriate to guarantee reliable and robust results. The widespread use of glyphosate and its harmfulness to humans make its detection at trace levels a primary goal for analytical laboratories. This is achievable through the improvement of QA and/or the optimization of the method of analysis used for glyphosate detection.

Wheat amylase-trypsin inhibitors (ATIs) are a family of plant defense proteins with an important role in human health for their involvement in allergies, celiac disease and non-celiac wheat sensitivity. Information about the differences in ATI activities among wheat genotypes and the influence of the growing environment is scarce. Therefore, ten selected wheat accessions with different ploidy level and year of release, previously characterized for their ATI gene sequences, were grown during three consecutive crop years at two growing areas and used for in vitro ATI activities. The contributions of the genotype and the crop year were significant for both activities. The hexaploid wheat genotypes showed the highest inhibitory activities. Einkorn had a peculiar behavior showing the lowest alpha-amylase inhibitory activity, but the highest trypsin inhibitory activity. It was not possible to observe any trend in ATI activities as a function of the release year of the wheat samples. The two inhibitory activities were differently affected by the growing conditions and were negatively correlated with the protein content. This information can be important in understanding the extent of variation of ATI inhibitory properties in relation to the wheat genotype and the growing environment and the impact of ATIs, if any, on human health and nutrition.