The red imported fire ants, Solenopsis invicta Buren are one of the serious pests in the world. Recently, S. invicta and S. germinata were found at Gamman pier, Pusan port in Korea by Animal and Plant Quarantine Agency. It is difficult to discriminate between S. invicta and S. germinata because of their morphology. Although DNA barcoding is an efficient method for species identification based on partial sequence of the mitochondrial cytochrome oxidase I gene(COI), amplification of non-target sequences or heteroplasmic COI sequences may result in the failure of Sanger sequencing. To overcome these limitations, application of next generation sequencing platforms is an alternative method. Here, we developed SNP markers using NGS technologies to distinguish two fire ants accurately and easily. For read mapping from high-throughput sequencing data, we used S. invicta reference genome version Si_gnG downloaded from NCBI database. Samtools were used for genotypes calling after mapping read to reference genome by BWA. After coding sequence SNPs that clearly distinguish S. invicta and S. geminata from one candidate gene were selected, the SNPs were validated additional Sanger sequencing using various accessions, including S. invicta and S. geminata. Our results demonstrated that detection of S. invicta from Solenopsis genus group could be accurately and quickly detected by these markers.

Autophagy is known to be involved in a variety of biological processes. However, relatively a little is known regarding oocyte maturation and preimplantation development in mammals. Thus, the current study was conducted to investigate the role of autophagy in oocyte maturation and subsequent preimplantation development in pigs. Porcine oocytes were matured in the presence or absence of 1 μM rapamycin, an autophagy inducing agent, fertilized in vitro, and cultured to blastocyst stage. From Western blotting analysis, we found that active form LC3 was detected during in vitro maturation (IVM) period, suggesting the possible role of autophagy in oocyte maturation. Interestingly, treatment of rapamycin during IVM significantly increased nuclear maturation compared to control group. Importantly, rapamycin-assisted IVM greatly improved monospermic fertilization and blastocyst development rates compared to control embryos. In addition, we also found that cell number and blastomere survival in blastocysts were markedly increased in rapamycin treatment group, which was further evidenced by both elevation of anti-apoptotic transcript Bcl-XL and decrease of pro-apoptotic transcript Bax. Collectively, these results strongly suggest that induction of autophagy may contribute to the completion of nuclear and cytoplasmic maturation of porcine oocytes.

Despite of the presence of estradiol-17β (E2) in ovarian follicles, its role(s) in in vitro maturation (IVM) is still largely unknown, especially in pigs. Thus, the current study was conducted to investigate the effect of E2 on in vitro maturation (IVM) of porcine oocytes and subsequent preimplantation development using in vitro fertilization (IVF)- or somatic cell nuclear transfer (SCNT)-derived embryos. To define the effects of E2 on IVM and early embryogenesis, porcine oocytes were matured in the presence or absence of E2, fertilized in vitro and cultivated to blastocyst stage. Compared to control group, the production of MII oocytes was significantly increased by treatment with E2, accompanying with the increase in MPF content and ERK phosphorylation, and monospermic fertilization and blastocyst development rates were also greatly elevated in the E2-treated oocytes. In addition, the advantageous role of E2 was also found in blastomere survival, which was further evidenced by both elevation of anti-apoptotic transcript Bcl-XL and decrease of pro-apoptotic transcript Bax. Furthremore, these positive effects of E2 were highly reproducible in early development of SCNT embryos. Collectively, the current study strongly suggests that E2 can be used as a efficient IVM supplement leading to successful nuclear/cytoplasmic maturatioin in pigs.