Integrative and conjugative elements (ICEs) of the ICESa2603 family have been isolated from several species of Streptococcus spp.; however, the comparative genomic and evolutionary analyses of these particular ICEs are currently only at their initial stages. By investigating 13 ICEs of the ICESa2603 family and two ICESa2603 family-like ICEs derived from diverse hosts and locations, we have determined that ICEs comprised a backbone of 30 identical syntenic core genes and accessory genes that were restricted to the intergenic sites or the 3′-end of the non-conserved domain of core genes to maintain its function. ICESa2603 family integrase IntICESa2603 specifically recognized a 15-bp att sequence (TTATTTAAGAGTAAC) at the 3′-end of rplL, which was highly conserved in genus Streptococcus. Phylogenetic analyses suggest that extensive recombination/insertion and the occurrence of a hybrid/mosaic in the ICESa2603 family were responsible for the significant increase in ICE diversity, thereby broadening its host range. Approximately 42.5 and 38.1% of the tested Streptococcus suis and Streptococcus agalactiae clinical isolates respectively contained ICESa2603 family Type IV secretion system (T4SS) genes, and 80.5 and 62.5% of which also respectively carried intICESa2603, indicating that ICESa2603 family is widely distributed across these bacteria. Sequencing and conjugation transfer of a novel sequence type ST303 clinical S. suis isolate HB1011 demonstrated that the 89K-subtype ICESsuHB1011 retained its transferrable function, thereby conferring tetracycline and macrolide resistance.

ST7 is widespread in many regions of China and a clonal dissemination occurred between Sichuan and Jiangsu provinces in diseased pigs. However, ST1 strains with macrolide and tetracycline resistance (ermB(+) +tetO(+) +ST1) isolated from a farm in Hebei province demonstrated that the genetic diversity was contributed by horizontal acquiring of ermB and tetO carrying elements.

Autophagy is one of the basic cellular mechanism during preimplantation development of mammalian embryos, and it plays crucial role in several physiological processes. It is induced by interleukin (IL)‐1β in mammalian cells. Our present study shows that IL‐1β is important for autophagy activation in embryo development. Our in vitro culture system analysis shows effect of IL‐1β in medium on the development of mouse embryos and it was found to be concentration dependent. A preimplantation embryo culture using medium containing IL‐1β did not improve cleavage and blastocyst development rates of mouse embryos; however, blastocyst quality was significantly improved by increasing total cell number, especially in supplementary 20 ng/mL IL‐1β. Furthermore, autophagy activation mainly occurs in 2 to 4 cell embryo and blastocyst, 20 ng/mL IL‐1β into culture medium can effectively enhance levels of messenger RNA and protein of autophagy‐related‐factors in 2 to 4 cell embryos and blastocyst, while these factors reduce in VGX‐1027 (IL‐1β inhibitor) groups that also reduce the quality of blastocyst. Effects of IL‐1β on the development of embryo reduced in 20 ng/mL IL‐1β supplemented group when 5 mM 3‐methyladenine (3‐MA) was also added, which used to inhibit autophagy activation in endogenous PtdIns3Ks signal pathway. Our current results show that exogenous IL‐1β can effectively induce autophagy in mouse embryos at stages of 2 to 8 cell and blastocyst, that also help to improve the quality of blastocyst.

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