The objective of the present study was to investigate the effects of different concentrations of sorbitol supplementation for in vitro maturation medium and in vitro culture medium, on porcine cumulus oocyte complexe(COC) maturation and subsequent developmental capacity after parthenogenetic activation. Porcine COC were cultured for 44 h(0～ 22 h termed MI stage and 22～44 h termed MII stage) in TCM199 without(— ) or with(+) sorbitol (20 μM, 100 μM, 200 μM), and the resultant metaphase II oocytes cultured in PZM-3 for 7 days following activation. Our results showed that supplementation with appropriate concentrations of sorbitol (20 μM) during full term maturation culture(MI+/MII+) significantly(p<0.05) improved blastocyst formation rates and total cell number. When the concentration of sorbitol were increased to 100 μM and 200 μM during maturation culture, the maturation rate of COC were significantly reduced compared with 20 μΜ or control groups. Also blastocyst formation rates significantly(p<0.05) reduced with increasing concentration of sorbitol(200 μM). Supplementation with sorbitol(20 μM, 50 μM, 100 μM) into PZM-3 for in vitro culture significantly(p<0.05) inhibited blastocyst formation compared with control group. However, the blastocyst formation rates start to rise again when 50 μ M sorbitol was used for the first 48 hours and then cultured in PZM-3 without sorbitol. There was no significant difference in cell number between control and sorbitol treated groups. When the activated oocytes were cultured in PZM-3 for 48h and then cultured in PZM-3 with sorbitol, interestingly, the blastocyst formation rate was similar to that of PZM-3 with sorbitol for in vitro culture and significantly lower than control group. These results suggest that addition of low concentrations of sorbitol(20 μM) during oocyte maturation is beneficial for subsequent blastocyst development and improved embryo quality. However, treatment with sorbitol supplementation during in vitro culture medium is negative effect to blastocyst formation.

Environmental stresses including drought, extreme temperatures, and high salinity are major factors that severely limit crop productivity worldwide. To overcome yield loss due to these environmental stresses, a large number of researches have been conducted to understand how plants respond to and adapt these environmental stresses. Posttranscriptional regulation as well as transcriptional regulation of gene expression is recognized as a key regulatory process in plant stress responses, and these cellular processes are regulated by diverse RNA-binding proteins (RBPs). Over the last years, we have extensively investigated the functional roles of RBPs that harbor an RNA-recognition motif at the N-terminal half and a glycine-rich region at the C-terminal half (glycine-rich RNA-binding proteins, GRPs), zinc finger-containing GRP, and cold shock domain proteins (CSDPs) in Arabidopsis thaliana, rice (Oryza sativa), wheat (Triticum aestivum), and rapeseed (Brasicca napus) under stress conditions. Our comparative analysis demonstrated that certain family members display RNA chaperone function during stress adaptation process in monocotyledonous plants as well as in dicotyledonous plants. These findings point to the importance of the regulation of mRNA metabolism in plant response to environmental stresses and shed new light on the practical application of these RBPs to develop stress-tolerant transgenic crops.