Overexpression of tryparedoxin after irradiation was also observed, indicating that the parasite may be responding to the oxidative Terbutaline Sulfate stress caused by irradiation. We also compared the time-course microarray and proteomic analyses. Although some of the protein expression patterns confirmed the microarray results, the correlation between mRNA and protein levels of the genes identified in both studies was extremely poor. In addition, treatment of the parasites with translation inhibitors showed that the synthesis of proteins putatively involved in the parasite response to stress is essential for its recovery from such a harmful stress. When we considered the expected molecular weight of the fulllength isoform of both upregulated and downregulated proteins, we noticed a decrease in protein size in the former case and an increase in the latter case, thus showing the emergence of lower molecular weight protein isoforms after irradiation. We then decided to confirm if the observed molecular weight of these proteins in the 2D gels was in agreement with their expected molecular weight. In the case of upregulated proteins, the observed molecular weight was significantly lower than expected, indicating that these proteins might be processed, yielding shorter polypeptides. It is important to note that this result does not seem to be a consequence of protein degradation, since clear spots can be observed in the 2D gel, indicating the presence of a large amount of identical polypeptides in this region of the gel. This would not be the case if proteins were degraded, considering that in this situation peptides of variable size would be generated and no clear spot would be observed in the gel. These results may indicate the emergence of new protein isoforms, as the result of protein processing, alternative splicing of mRNAs, and/or alternative translational start/stop sites after irradiation. Alternative splicing of transcripts has the potential to expand the repertoire of proteins. Recent studies have estimated that all multi-exonic human genes are able to produce at least two alternatively Anisotropine Methylbromide spliced mRNA transcripts by alternative splicing, generating different proteins isoforms with altered structures and biological functions.