Novel SLC20A2 mutations identified in southern Chinese patients with idiopathic basal ganglia calcification

Idiopathic basal ganglia calcification (IBGC) is a rare neuropsychiatric disorder characterized by bilateral and symmetric cerebral calcifications. Recently, SLC20A2 was identified as a causative gene for familial IBGC, and three mutations were reported in a northern Chinese population. Here, we aimed to explore the mutation spectrum of SLC20A2 in a southern Chinese population. Sanger sequencing was employed to screen mutations within SLC20A2 in two IBGC families and 14 sporadic IBGC cases from a southern Han Chinese population. Four novel mutations (c.82G > A p.D28N, c.185T > C p.L62P, c.1470_1478delGCAGGTCCT p.Q491_L493del and c.935-1G > A) were identified in two families and two sporadic cases, respectively; none were detected in 200 unrelated controls. No mutation was found in the remaining 12 patients. Different mutations may result in varied phenotypes, including brain calcification and clinical manifestations. Our study supports the hypothesis that SLC20A2 is a causative gene of IBGC and expands the mutation spectrum of SLC20A2, which facilitates the understanding of the genotype–phenotype correlation of IBGC.     

Poster Sessions CP13: Hypoxia,Ischemia and Oxidative Stress. Changes of brain nitric oxide production in experimental cerebral ischemia

In order to study the role of nitric oxide (NO) in ischemic brain injury. Global cerebral ischemia was established in SD rats by modified Pulsinelli's method. The activities of constitutive nitric oxide synthase (cNOS), inducible NOS (iNOS), neuronal NOS (nNOS), nitrite (NO₂) and cyclic GMP in cerebral cortex, hippocampus, striatum and cerebellum at different time intervals were measured by radioimmunoassy, NADPH‐d histochemistry and fluorometry methods. The results showed that the activities of cNOS increased at 5 min in four regions and decreased in cortex, hippocampus and striatum at 60 min, in cerebellum at 15 min iNOS increased in cortex and striatum at 15 min, in hippocampus and cerebellum at 10 min, and persisted to 60 min. The expression of nNOS increased after 5 min ischemia in cortex, striatum and hippocampus, and return to normal at 30–60 min. The NO₂ and cGMP also increased after 5–15 min ischemia and returned to normal after 30–60 min ischemia. These results indicated that the NO participated in the pathogenesis of cerebral ischemia injury and different types of NOS play different role in the cerebral ischemia injuries. Selected specific NOS inhibitors to decreased the excessive production of NO at early stage may help to decrease the ischemic injury.     

湿地松粉蚧本地寄生天敌-粉蚧长索跳小蜂

本文简要介绍了湿地松粉蚧在广东的发生、危害状况,描述了最近在疫区局部地区新发现的一种本地寄生蜂-粉蚧长索跳小蜂,并探讨其利用前景.     

水位影响泥炭沼泽土壤有机碳分解的生物化学机制研究进展

在人类活动和气候变化影响下，泥炭沼泽生态系统急剧退化，其独特的氧化还原过程使得退化泥炭沼泽及其恢复过程中土壤有机碳（SOC）分解与存储机制成为研究的热点问题。泥炭沼泽排水/再湿过程会显著改变土壤的氧化还原条件，进而改变土壤微生物群落和酶活性，驱动铁氧化还原过程，影响SOC分解。已有研究对"缺氧是维持泥炭地碳存储的关键"的传统理论提出了质疑，而土壤酶及铁（Fe）在土壤SOC分解与存储过程中分别扮演着"酶锁"和"铁门"的作用，二者同时受到氧化还原条件的影响。然而，有关退化泥炭沼泽及其恢复过程中酶-土壤SOC-Fe相互作用及微生物驱动机制还有待深入。总结了干旱/排水/再湿对泥炭沼泽土壤SOC组分、分子结构、碳排放的影响，并从微生物、酶、Fe化学的角度归纳总结了泥炭沼泽土壤SOC分解的生物化学机制。未来研究中应将土壤水分与土壤SOC分解的生物地球化学机制联系起来，探寻水位变化过程中生物及非生物要素对土壤SOC分子结构变化的调控机制及土壤氧化酶-酚类物质/SOC分子结构-水解酶之间的作用机制。同时，关注Fe的氧化和还原过程，评估Fe-SOC在泥炭沼泽土壤有机碳中的地位，利用分子生物学手段探究水位变化过程中酶-SOC分解/碳排放-铁之间的权衡机制。     

Application of convolutional neural network on early human embryo segmentation during in vitro fertilization

Selection of the best quality embryo is the key for a faithful implantation in in vitro fertilization (IVF) practice. However, the process of evaluating numerous images captured by time-lapse imaging (TLI) system is time-consuming and some important features cannot be recognized by naked eyes. Convolutional neural network (CNN) is used in medical imaging yet in IVF. The study aims to apply CNN on day-one human embryo TLI. We first presented CNN algorithm for day-one human embryo segmentation on three distinct features: zona pellucida (ZP), cytoplasm and pronucleus (PN). We tested the CNN performance compared side-by-side with manual labelling by clinical embryologist, then measured the segmented day-one human embryo parameters and compared them with literature reported values. The precisions of segmentation were that cytoplasm over 97%, PN over 84% and ZP around 80%. For the morphometrics data of cytoplasm, ZP and PN, the results were comparable with those reported in literatures, which showed high reproducibility and consistency. The CNN system provides fast and stable analytical outcome to improve work efficiency in IVF setting. To conclude, our CNN system is potential to be applied in practice for day-one human embryo segmentation as a robust tool with high precision, reproducibility and speed.     

Molecular analysis of SMN1, SMN2, NAIP, GTF2H2, and H4F5 genes in 157 Chinese patients with spinal muscular atrophy

Spinal muscular atrophy (SMA) is a common and lethal autosomal recessive neurodegenerative disorder, which is caused by mutations of the survival motor neuron 1 (SMN1) gene. Additionally, the phenotype is modified by several genes nearby SMN1 in the 5q13 region. In this study, we analyzed mutations in SMN1 and quantified the modifying genes, including SMN2, NAIP, GTF2H2, and H4F5 by polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP), multiplex ligation-dependent probe amplification (MLPA), TA cloning, allele-specific long-range PCR, and Sanger sequencing in 157 SMA patients. Most SMA patients (94.90%) possessed a homozygous SMN1 deletion, while 10 patients demonstrated only the absence of exon 7, but the presence of exon 8. Two missense mutations (c.689 C > T and c.844 C > T) were identified in 2 patients who both carried a single copy of SMN1. We found inverse correlations between SMN2, the NAIP copy number, and the clinical severity of the disease. Furthermore, 7 severe type I patients possessed large-scale deletions, including SMN1, NAIP, and GTF2H2. We conclude that SMN1 gene conversion, SMN1 subtle mutations, SMN2 copy number, and the extent of deletion in the 5q13 region should all be considered in the genotype–phenotype analysis of SMA.