The finding that caspase-8 and caspase-3 was processed in activated T cells in the absence of apoptotic features, suggests that the apoptotic pathway must be inhibited at some stage downstream of caspase-8 and caspase-3 processing. In the present study, the caspase-3 substrate, see more PARP remained intact, suggesting that caspase-3 activity was held in check prior to the processing of PARP. This is in agreement with previous study where PARP was not cleaved in activated T cells (Deas et al., 1998). The finding that caspase-3 was only processed as far as the p20 subunit in activated T cells does not account for the lack of PARP cleavage, since removal of the N-terminal prodomain and thus generation of the p17 subunit from the

p20 is not required for caspase-3 to cleave PARP (Stennicke et al., 1998). However, in contrast to the findings in this study, other studies have demonstrated PARP processing, in the absence of apoptotic features in activated T cells (Alam et al., 1999 and Wilhelm et al., 1998). Therefore, the mechanism for the prevention of apoptosis, despite the presence of processed caspases remains to be determined. In summary, the results presented here show that caspase processing in activated T cells is not inhibited by z-VAD-FMK or z-IETD-FMK. Since both z-VAD-FMK

and z-IETD-FMK effectively inhibited T cell proliferation, HSP assay but had minimal effects on caspase processing in activated T cells, it is unlikely that the inhibition of caspase processing is the means by which they exert their inhibitory

effect. Indeed, it has recently been reported that z-VAD-FMK inhibits the enzymatically active proform of caspase-8 which is required for TCR-mediated NF-κB activation, rather than processed caspase-8 (Su et al., 2005). Further work is required to determine whether z-VAD-FMK inhibits pro-caspase-8 activity and whether z-IETD-FMK has a similar effect. The finding that z-FA-FMK inhibited caspase-8 and caspase-3 processing in activated T cells but did not inhibit caspases per se suggests that it inhibits an upstream mediator of caspase processing during T cell activation ( Lawrence et al., 2006). Morin Hydrate Furthermore, the disparate effects of these peptidyl-FMK inhibitors on caspase-8 and caspase-3 processing during T cell activation and Fas-mediated apoptosis suggests that these processes are regulated by distinct mechanisms. The authors declare that there are no conflicts of interest. This work was supported by the Medical Research Council, United Kingdom and funds from Monash University Sunway Campus, Malaysia. “
“Unlike fossil fuels, alternative fuels such as ethanol are considered environmentally friendly. In Brazil, the use of biofuels, described as clean alternatives to oil, has improved the air quality in major urban centers. However, biomass burning in regions of sugarcane cultivation, where the crops are burned in order to facilitate harvesting and increase the yield per ton (Zamperlini et al.