RESUMO
Background: Selection of sperm for intracytoplasmic sperm injection [ICSI] is usually considered as the ultimate technique to alleviate male-factor infertility. In routine ICSI, selection is based on morphology and viability which does not necessarily preclude the chance injection of DNA-damaged or apoptotic sperm into the oocyte. Sperm with high negative surface electrical charge, named [Zeta potential], are mature and more likely to have intact chromatin. In addition, X-bearing spermatozoa carry more negative charge. Therefore, we aimed to compare the clinical outcomes of Zeta procedure with routine sperm selection in infertile men candidate for ICSI
Materials and Methods: From a total of 203 ICSI cycles studied, 101 cycles were allocated to density gradient centrifugation [DGC]/Zeta group and the remaining 102 were included in the DGC group in this prospective study. Clinical outcomes were com- pared between the two groups. The ratios of Xand Y bearing sperm were assessed by fluorescence in situ hybridization [FISH] and quantitative polymerase chain reaction [qPCR] methods in 17 independent semen samples
Results: In the present double-blind randomized clinical trial, a significant increase in top quality embryos and pregnancy rate were observed in DGC/Zeta group compared to DGC group. Moreover, sex ratio [XY/XX] at birth significantly was lower in the DGC/Zeta group compared to DGC group despite similar ratio of X/Y bearings sper- matozoa following Zeta selection
Conclusion: Zeta method not only improves the percentage of top embryo quality and pregnancy outcome but also alters the sex ratio compared to the conventional DGC method, despite no significant change in the ratio of Xand Ybearing sperm population
RESUMO
PhiC31 integrase system provides a new platform in various felid of research, mainly in gene therapy and creation of transgenic animals. This system enables integration of exogenous DNA into preferred locations in mammalian genomes, which results in robust, long-term expression of the integrated transgene. Identification of a novel pseudo attP site. Genomic DNA was extracted from primary bovine fetal fibroblast cells, which were stably trans-fected with EGFP and phiC31 integrase cDNAs carrying vectors. An inverse PCR was carried out for production of mini-circle DNAs and followed by sequencing. A new specific pseudo attP site termed BF5 was identified in bovine genome. This site is located in an intergenic AT rich region on chromosome 5 with similar features of other mammalian attP pseudo sites. Furthermore, direct sequencing of generated attL site confirmed that site-specific transgene recombination was occurred at this site. This finding confirmed that phiC31 integrase could be feasible for production of transgenic animals for biotechnological applications
RESUMO
The aim of present study was cloning and expression of phiC31 integrase cDNA in a bacterial expression vector. Thus, an intra molecular assay vector was applied to show in vitro activity of recombinant protein. In this experimental study, phiC31 cDNA was subcloned into a prokaryotic expression vector and transformed into E.coli Bl21 [DE3]. Recombinant phiC31 integrase was purified form the bacterial cell lysates and its activity was verified by an in vitro functional assessment. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis [SDS-PAGE] of the purified phiC31 integrase confirmed the size of protein [70 kDa]. Finally, the functionality of purified phiC31 integrase was verified. The results of this study indicated that the purified integrase has a great potential application for in vitro site-specific integration