DNA methylation is involved in sexual differentiation and sex chromosome evolution in the dioecious plant garden asparagus.

DNA methylation is a crucial regulatory mechanism in many biological processes. However, limited studies have dissected the contribution of DNA methylation to sexual differentiation in dioecious plants. In this study, we investigated the variances in methylation and transcriptional patterns of male and female flowers of garden asparagus. Compared with male flowers, female flowers at the same stages showed higher levels of DNA methylation. Both male and female flowers gained DNA methylation globally from the premeiotic to meiotic stages. Detailed analysis revealed that the increased DNA methylation was largely due to increased CHH methylation. Correlation analysis of differentially expressed genes and differentially methylated regions suggested that DNA methylation might not have contributed to the expression variation of the sex-determining genes SOFF and TDF1 but probably played important roles in sexual differentiation and flower development of garden asparagus. The upregulated genes AoMS1, AoLAP3, AoAMS, and AoLAP5 with varied methylated CHH regions might have been involved in sexual differentiation and flower development of garden asparagus. Plant hormone signaling genes and transcription factor genes also participated in sexual differentiation and flower development with potential epigenetic regulation. In addition, the CG and CHG methylation levels in the Y chromosome were notably higher than those in the X chromosome, implying that DNA methylation might have been involved in Y chromosome evolution. These data provide insights into the epigenetic modification of sexual differentiation and flower development and improve our understanding of sex chromosome evolution in garden asparagus.

Clinical analysis of the incidence and the treatment of pediatric cataract patients with optic-nerve maldevelopment.

PURPOSE: To interpret the incidence of optic-nerve maldevelopment in postoperative pediatric cataract patients, and evaluate the clinical efficacy of administration of murine nerve growth factor (mNGF) in such patients. METHODS: Pattern visual evoked potential (P-VEP) was used to measure the visual pathway function in 28 cases (56 eyes) with bilateral congenital cataract and 13 cases (13 eyes) with unilateral congenital cataract who underwent cataract extraction and intraocular lens implantation surgeries. The results were compared with 25 age-sex-matched healthy children (50 eyes). mNGF was administered in 13 cases (23 eyes) who had visual pathway disorder. The efficacy of mNGF injection was observed. P100 latencies, which were used as a main parameter in P-VEP measurement, were analyzed statistically. RESULTS: When compared with normal children, the P100 latency was significantly prolonged in the congenital cataract group (P < 0.05). A significant improvement was noted in the visual pathway of subjects treated with mNGF (P < 0.05). CONCLUSION: Compared with normal children, the congenital cataract patients are more vulnerable to optic-nerve maldevelopment. Murine NGF likely plays a protective and nutritive role in the development of optic nerve in cases of optic-nerve maldevelopment followed by congenital cataract surgery.

Ten-year etiologic review of Chinese children hospitalized for pediatric cataracts.

PURPOSE: Our aim was to obtain a better understanding of the etiologies and characteristics of pediatric cataracts treated at a single facility in China. METHODS: Medical records accrued over a 10-year period (from August, 2003 to July, 2013) at Shengjing Hospital of China Medical University were reviewed retrospectively, identifying all patients treated for various subtypes of pediatric cataract. A database with 367 subjects under 14 years of age (598, including second-round surgeries) was generated. RESULTS: Of this cohort (n = 367; males: 232, 63.2%; females: 135, 36.8%), 200 patients (54.5%) had bilateral cataracts, and 258 (70.3%) were under 3 years of age. In all age groups and in all subtypes of pediatric cataract, males were most commonly affected. Congenital cataract was the most prevalent subtype, accounting for 296 patients (80.7%). Most congenital cataracts were associated with other ocular or systemic abnormalities; and in 48 patients (16.22%), they were hereditary. Traumatic cataract was the most common subtype (85.92%) of acquired cataract. The few instances of cataracts due to steroids (n = 3) or to metabolic disorders (n = 2) occurred in males and involved both eyes. CONCLUSION: The majority of pediatric cataracts in this patient population were congenital in nature. A significant lag in ophthalmologic evaluation of Chinese infants was evident and should be addressed by educating both children and parents on risk factors for cataract development. Regular assessments are especially important in children subjected to long-term systemic steroid treatments.