The influence of temperature on the development and embryonation of Ascaris suum eggs was studied using coarse sand medium in an environmental chamber with 50% humidity. The time required for development and embryonation of eggs was examined under 3 different temperature conditions, 5degrees C, 25degrees C, and 35degrees C. A. suum eggs did not develop over 1 month at the temperature of 5degrees C. However, other temperature conditions, 25degrees C and 35degrees C, induced egg development to the 8-cell-stage at days 5-6 after incubation. All eggs examined developed to the 8-cell stage at day 6 after incubation in the sand medium at 25degrees C. The higher temperature, 35degrees C, slightly accelerated the A. suum egg development compared to 25degrees C, and the development to the 8-cell stage occurred within day 5 after incubation. The formation of larvae in A. suum eggs at temperatures of 35degrees C and 25degrees C appeared at days 17 and 19 after incubation, respectively. These findings show that 35degrees C condition shortens the time for the development of A. suum eggs to the 8-cell-stage in comparison to 25degrees C, and suggest the possibility of accelerated transmission of this parasite, resulting from global warming and ecosystem changes.
Animals ; Ascaris suum/*embryology/growth & development/*radiation effects ; Culture Media ; Eggs/radiation effects ; Humidity ; Larva/growth & development/radiation effects ; Silicon Dioxide ; Temperature

Ascaris suum eggs are inactivated by composting conditions; however, it is difficult to find functional changes in heat-treated A. suum eggs. Here, unembryonated A. suum eggs were incubated at 20degrees C, 50degrees C, and 70degrees C in vitro, and the gene expression levels related to viability, such as eukaryotic translation initiation factor 4E (IF4E), phosphofructokinase 1 (PFK1), and thioredoxin 1 (TRX1), and to apoptosis, such as apoptosis-inducing factor 1 (AIF1) and cell death protein 6 (CDP6), were evaluated by real-time quantitative RT-PCR. No prominent morphological alterations were noted in the eggs at 20degrees C until day 10. In contrast, the eggs developed rapidly, and embryonated eggs and hatched larvae began to die, starting on day 2 at 50degrees C and day 1 at 70degrees C. At 20degrees C, IF4E, PFK1, and TRX1 mRNA expression was significantly increased from days 2-4; however, AIF1 and CDP6 mRNA expression was not changed significantly. IF4E, PFK1, and TRX1 mRNA expression was markedly decreased from day 2 at 50degrees C and 70degrees C, whereas AIF1 and CDP6 mRNA expression was significantly increased. The expressions of HSP70 and HSP90 were detected for 9-10 days at 20degrees C, for 3-5 days at 50degrees C, and for 2 days at 70degrees C. Taken together, incremental heat increases were associated with the rapid development of A. suum eggs, decreased expression of genes related to viability, and earlier expression of apoptosis-related genes, and finally these changes of viability- and apoptosis-related genes of A. suum eggs were associated with survival of the eggs under temperature stress.
Animals ; *Apoptosis ; Ascaris suum/*genetics/*radiation effects ; Cell Survival/radiation effects ; Eggs/radiation effects ; Female ; Gene Expression Profiling ; Gene Expression Regulation/*radiation effects ; Real-Time Polymerase Chain Reaction ; Survival Analysis ; Temperature