Effect of Mouse Ovarian Vitrification on Promoter Methylation of Inhba and Inhbb in Granulosa Cells of Follicles.

BACKGROUND: Cryopreservation can induce cellular, genomic, and epigenetic abnormalities. OBJECTIVE: To analyse the impact of ovarian vitrification on follicular development and its epigenetic effect on promoter methylation of Inhba and Inhbb in granulosa cells. MATERIALS AND METHODS: Mouse ovaries were divided into control, toxicity, and vitrified groups. The growth and development of follicles were examined. After in vitro culture of follicles, DNA was extracted from isolated granulosa cells and treated with sodium bisulfite. The promoter methylation of Inhba and Inhbb was analyzed by direct PCR sequencing. RESULTS: Vitrification reduced the growth of follicles; however, antral cavity formation was not influenced negatively. Vitrification reduced the percentage of 5-methylcytosine in the Inhba promoter, while CpG sites in the promoter of Inhbb remained unmethylated. CONCLUSION: Vitrification had adverse effects on follicle growth and the epigenetics of granulosa cells. The results of the current study show that vitrification methods of ovary need more improvement.

Distribution of insertion sequences associated with Tn1546 and clonal diversity of vancomycin-resistant enterococci isolated from patients in Tehran, Iran.

BACKGROUND AND OBJECTIVES: Infection with vancomycin-resistant enterococci (VRE) has caused a therapeutic problem. VanA and VanB resistant types are the predominant phenotypes among vancomycin resistant enetrococci. Transposon 1546 (Tn1546) harboring the vanA gene cluster, plays an important role in the horizontal transfer of vanA gene. In this study, we examined the phenotypic and genotypic diversity of a number of clinical VRE. MATERIALS AND METHODS: Twenty-four clinical VRE isolated from two university hospitals in Tehran were examined based on their antimicrobial susceptibility, Tn1546 related element organization and pulsed-field gel electrophoresis (PFGE) patterns. Integration of well-studied insertion sequence elements IS1216V, IS1542 and IS1251 was examined by PCR mapping and sequencing. RESULTS: From 24 isolates, 15 isolates with VanA phenotype and 9 isolates with VanB phenotype were identified which both groups interestingly possessed the vanA gene. According to PCR mapping, our isolates were assigned to 6 main groups. In 14 (58.3%) isolates, IS1216V was inserted in vanX-vanY region and/or in truncated left-hand of Tn1546-like elements. In 11 (45.8%) isolates, both IS1216V and IS1542 were inserted in vanX-vanY and orf2-vanR regions, respectively and none of them harbored IS1251. Interestingly, PFGE of the isolates showed a high degree of diversity. CONCLUSION: PCR mapping revealed that VanA elements in our isolates were highly heterogeneous. Overall, we found no correlation between transposon type and PFGE pattern. Genetic diversity of VRE provides practical information for epidemiological studies and our data showed horizontal transfer of VRE in this region.