Screening of common deafness gene mutations in 17 000 Chinese newborns from Chengdu based on microarray analysis / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To achieve early diagnosis for inheritable hearing loss and determine carrier rate of deafness causing gene mutations in order to provide information for premarital, prenatal and postnatal genetic counseling.</p><p><b>METHODS</b>A total of 17 000 dried heel blood spots of normal newborns in Chengdu were collected with informed consent obtained from their parents. Genomic DNA was extracted from dried blood spots using Qiagen DNA extraction kits. Microarrays with 9 common mutation loci of 4 deafness-associated genes in Chinese population were used. Nine hot mutations including GJB2 (35delG, 176del16, 235delC and 299delAT), GJB3 (538C> T), SLC26A4 (IVS 7-2A> G, 2168A> G), and mitochondrial DNA 12S rRNA (1555A> G, 1494C> T) were detected by PCR amplification and microarray hybridization. Mutations detected by microarray were verified by Sanger DNA sequencing.</p><p><b>RESULTS</b>Of the 17 000 new-borns, 542 neonates had mutations of the 4 genes. Heterozygous mutations of GJB2, at 235delC, 299delAT, and 176del16 were identified in 254, 55, and 15 newborns, respectively. Two newborns had homozygous mutation of GJB2, 235delC. Heterozygous mutations at 538C> T of GJB3, 2168A> G and IVS 7-2A> G of SLC26A4 were found in 23, 17 and 128 newborns, respectively. For mutation analysis of mitochondrial DNA 12S rRNA, 1494C> T and 1555A> G were homogeneous mutations in 4 and 42 neonates, respectively. In addition, 6 complexity mutations were detected, which demonstrated that one newborn had heterozygous mutations at GJB2 235delC and SLC26A4, IVS7-2A> G, one had heterozygous mutation GJB2 235delC and 12S rRNA homogeneous mutation, 1555 A> G, one heterozygous mutations at GJB2, 299delAT, and GJB3, 538C> T, one at GJB2, 299delAT and 12S rRNA, 1555 A> G, two at GJB2, 299delAT, and SLC26A4, IVS7-2A> G. All mutations as above were confirmed by DNA sequencing.</p><p><b>CONCLUSION</b>The total mutation carrier rate of the 4 deafness genes is 3.19% in healthy newborns at Chengdu. Mutations of GJB2 and SLAC26A4 are major ones (86.5% of total). The mutation rate of mitochondrial DNA 12S rRNA is 2.71‰, which may have deafness induced by aminoglycoside antibiotics. Newborn screening for mutation of genes related to hereditary deafness plays an important role in the early detection and proper management for neonatal deafness as well as genetic counseling for premarital, prenatal and postnatal diagnosis.</p>

Pollen viability and stigma receptivity of Angelica dahurica from Sichuan and Hebei province / 中国中药杂志

<p><b>OBJECTIVE</b>To provide theoretical basis for artificial cross breeding of Angelica dahurica from Sichuan and Hebei Province, the characteristics of stigma receptivity and the viability and life-span of pollen were studied.</p><p><b>METHOD</b>The viability and life-span of pollen were evaluated by TTC (2, 3, 5-triphenyl tetrazlium chloride) test, and the stigma receptivity was estimated by benzidine-H2O2 method.</p><p><b>RESULT</b>The pollen viability of A. dahurica from Sichuan and Hebei provinces was increased gradually since the bud stage, but those levels had since subsided after the pollen release from craze antheral. There was a little difference in the pollen viability of A. dahurica from Sichuan at different branches. While the order of the pollen viability of A. dahurica from Hebei was main stem < first-order branching < second-order branching. At room temperature, the pollen viability of both decreased during time of anthers dehiscing but also above 50% after 5 days. Compared with 4 degrees C and room temperature, conservation at - 20 degrees C could extend life of the pollen. The stigma had receptivity in 4th day and reached the highest level in the 6th day after blooming.</p><p><b>CONCLUSION</b>The optimum artificial pollination times of A. dahurica was 6 days after blooming and choose the pollen in the peak stage of anthers dehiscing.</p>

Drought resistance of Angelica dahurica during seedling stage under polyethylene glycol (PEG-6000)-simulated drought stress / 中国中药杂志

<p><b>OBJECTIVE</b>To study the optimum conditions of simulated drought stress, and screen the indexes of drought resistance and comprehensively assess the drought resistance of the Angelica dahurica resources during seedling stage.</p><p><b>METHOD</b>Investigations were carried out on the changes of height, root length, root-shoot ration, contents of soluble sugar, proline and malondialdehyde under polyethylene glycol (PEG-6000)-simulated drought stress. A comprehensive evaluation on the drought resistance of different (varietal) species of A. dahurica during seedling stage was applied by using the method of subordinate function. And the drought resistance indexes were selected out by applying the method of grey correlative degree analysis.</p><p><b>RESULT</b>Drought stress of 9 days with 20% PEG was the optimum condition for the simulation of drought stress. The results showed that the drought resistant capability decreased in the order as follows, A. dahurica from Sichuan province, A. dahurica from Henan province, A. dahurica from Hebei province and A. dahurica from Zhejiang province. And the order of correlative degree of drought resistance and indexes was: soluble sugar > root length > proline > root-shoot ration > total content of chlorophyll > chlorophyll b > chlorophyll a > height > malondialdehyde.</p><p><b>CONCLUSION</b>Osmotic adjustment substance and the indexes related to the root have more influence on the drought resistance of A. dahurica during seedling stage. A. dahurica from Sichuan province shows the highest drought resistance during seedling stage.</p>