Upland rice and lowland rice exhibited different P/P expression under water deficit and ABA treatment

Aquaporins play a significant role in plant water relations.To further understand the aquaporin function in plants underwater stress,the expression of a subgroup of aquaporins,plasma membrane intrinsic proteins(PIPs),was studied at boththe protein and mRNA level in upland rice(Oryza sativa L.cv.Zhonghan 3)and lowland rice(Oryza sativa L.cv.Xiushui63)when they were water stressed by treatment with 20% polyethylene glycol(PEG).Plants responded differently to20% PEG treatment.Leaf water content of upland rice leaves was reduced rapidly.PIP protein level increased markedlyin roots of both types,but only in leaves of upland rice after 10h of PEG treatment.At the mRNA level,OsPIP1;2,Os-PIP1;3,OsPIP2;1 and OsPIP2;5 in roots as well as OsPIP1;2 and OsPIP1;3 in leaves were significantly up-regulatedin upland rice,whereas the corresponding genes remained unchanged or down-regulated in lowland rice.Meanwhile,weobserved a significant increase in the endogenous abscisic acid(ABA)level in upland rice but not in lowland rice underwater deficit.Treatment with 60μM ABA enhanced the expression of OsPIP1;2,OsPIP2;5 and OsPIP2;6 in roots andOsPIP1;2,OsPIP2;4 and OsPIP2;6 in leaves of upland rice.The responsiveness of PIP genes to water stress and ABAwere different,implying that the regulation of PIP genes involves both ABA-dependent and ABA-independent signalingpathways during water deficit.     

青藏高原东南部天然草地主要有毒植物调查研究

对青藏高原东南部的川西北天然草地主要有毒植物的种类、毒物成分和分布作了系统的调查与研究,首次报道了该区域天然草地有毒植物名录,统计出该区主要有毒植物226种,隶属于33科77属。有毒植物所含主要毒物成分可分为生物碱、苷类化合物、萜类化合物、苯酮类化合物、酚类及其衍生物和简单有机物等6大类。有毒植物在亚高山草甸草地中分布最多,有157种,其次是亚高山灌丛草地、高山草甸草地、高山灌丛草地和高寒沼泽化草甸草地。本调查研究为青藏高原东南部天然草地主要有毒植物的防除和开发利用奠定了基础。     

Temporal changes in genetic diversity of common bean (Phaseolus vulgaris L.) accessions cultivated between 1800 and 2000

Fourteen microsatellite markers were used to describe genetic diversity in a sample of 128 common bean (Phaseolus vulgaris L.) accessions cultivated within the territory of Slovenia and its nearby regions between 1800 and 2000. The accessions were grouped into three periods: period I comprising accessions from the beginning of the 19th century, while the other two periods included accessions from the middle (period II) and the end of the 20th century (period III). Seven control accessions of known Mesoamerican and Andean origin were also included in the study. A total of 130 alleles were generated. Allelic richness, in terms of number of alleles per locus, was 6.07 for period I, 6.71 for period II, and 6.07 for period III. In the UPGMA dendrogram, all studied accessions were intermixed in three main clusters, indicating that the diversity in the time periods overlapped. Two clusters consisted of accessions of Andean and Mesoamerican origin, while the third represents additional variation, which existed in this area already 200 years ago. The analysis of molecular variance showed that a great part of genetic diversity has been preserved till today, confirming the results of cluster analysis. The calculation of number of alleles per locus revealed no significant quantitative change in genetic diversity over the last 200 years of common bean cultivation. However, the calculation of genetic distances indicated slight qualitative shifts in genetic diversity of common bean germplasm over time, while the calculations of allelic frequency variation and polymorphic information content revealed recent decline of some alleles’ frequencies. These findings should stress the need for establishing an appropriate strategy of genetic resources management. The text was submitted by the authors in English.     

The Lin28/let-7a/c-Myc pathway plays a role in non-muscle invasive bladder cancer

We investigate the role of the Lin28/let-7a/c-Myc pathway in non-muscle invasive bladder cancer (NMIBC). Using RT-PCR, western blot and immunohistochemistry techniques, the levels of pre-let-7a, let-7a, Lin28 and c-Myc RNA and/or proteins were determined in samples of normal bladder tissue and bladder cancer. Expression of pre-let-7a was found to be negatively correlated with the pathological grade of bladder cancer, while let-7a showed a positive correlation with bladder cancer pathological grade. Expression of Lin28 RNA and protein was not significantly different between normal bladder tissue and low-grade transitional cell carcinoma of bladder (TCC) but the expression levels in high-grade TCC were remarkably increased. Expression of c-Myc RNA and protein was significantly higher in bladder cancer samples in comparison to normal bladder tissue without correlation with cancer differentiation. Expression of all the above RNAs and proteins showed no significant difference in Ta and T1 stages. The Lin28/let-7a/c-Myc pathway plays an important role in NMIBC. In particular, expression levels of let-7a correlate with the degree of cancer differentiation but not cancer stage.     

Protective effects of EphB2 on Aβ1–42 oligomer-induced neurotoxicity and synaptic NMDA receptor signaling in hippocampal neurons

Alzheimer’s disease (AD) is a neurodegenerative disorder characterized pathologically by the abnormal deposition of extracellular amyloid-β (Aβ) oligomers. However, the nature and precise mechanism of the toxicity of Aβ oligomers are not clearly understood. Aβ oligomers have been previously shown to cause a major loss of EphB2, a member of the EphB family of receptor tyrosine kinases. To determine the effect of EphB2 on Aβ oligomer-induced neurotoxicity and the underlying molecular mechanisms, we examined the EphB2 gene in cultured hippocampal neurons. Using a cellular model of AD, Aβ_1–42 oligomers were confirmed to induce neurotoxicity in a time-dependent manner and result in a major decrease of EphB2. EphB2 overexpression could prevent the neurotoxicity of hippocampal neurons from exposure to Aβ_1–42 oligomers for 1 h. Further analysis revealed that EphB2 overexpression increased synaptic NR1 and NR2B expression in Aβ_1–42 oligomer-treated neurons. Moreover, EphB2 overexpression prevented Aβ_1–42 oligomer-induced downregulation of dephosphorylated p38 MAPK and phosphorylated CREB. Together, these results suggest that EphB2 is a factor which protects hippocampal neurons against the toxicity of Aβ_1–42 oligomers, and we infer that the protection of EphB2 is achieved by increasing the synaptic NMDA receptor level and downstream p38 MAPK and CREB signaling in hippocampal neurons. This study provides new molecular insights into the neuroprotective effect of EphB2 and highlights its potential therapeutic role in the management of AD.     

利用环形染色体构象捕获技术对Bci11b基因座位在细胞核内空间组织的研究

环形染色体构象捕获（4c）技术实现了在全基因组范围内捕获与4c靶位点发生相互作用的基因座位,因而通过4C相关技术可以进一步研究靶基因座位在细胞核内的空间组织形式。该文以ABclllb基因座位作为4C分析的靶位点,通过优化4C分析的反向巢式PCR扩增条件,实现4C分析PCR的高效扩增：并通过有限克隆筛选与普通测序分析相结合的方法,在全基因组范围内捕获到一些与BcHlb基因座位发生潜在相互作用的基因座位。这些基因座位与靶位点间的相互作用既有发生在相同染色体内的,也有发生在不同染色体之间的。这些基因座位间的相互作用表明了Bclllb基因座位在细胞核内复杂的空间组织形式。     

Arsenic Resistance and Bioaccumulation of an Indigenous Bacterium Isolated from Aquifer Sediments of Datong Basin,Northern China

To obtain bacteria with arsenic accumulation potential that can be used to remove arsenic from contaminated waters, experiments were made to investigate the tolerance and accumulation to arsenic of an indigenous bacterium XZM002 isolated from aquifer sediments of Datong Basin, northern China. The results showed that strain XZM002 belongs to the genus Bacillus and has evolved defense mechanisms to reduce arsenic injury: the change of cellular shape from initial rod to oval and then to round with increment of arsenic toxicity. The effect of arsenate or arsenite on the bacterial growth was also investigated. Results showed that growth of the strain was inhibited under As(III) and high concentration As(V) (over 1200 μg l^?1) conditions in the first 2 days and promoted under low concentration As(V) (under 400 μg l^?1) condition. Its arsenic bioaccumulation potential was surveyed by monitoring the concentration changes of total arsenic and arsenic speciation in the medium and in the cytoplasm, and those of total arsenic on the membrane. Methylated arsenic species were not detected throughout the experiment. The results indicated that 11.5% of arsenic was removed from liquid medium into the bacterial cells and 9.22% of As(V) in the medium was transformed gradually to As(III) during 4 d of incubation. Approximately 80% of the total accumulated arsenic was adsorbed onto the membrane instead of into cytoplasm; and the arsenic accumulation almost approached saturation after incubation for 72 h.     

Exome sequencing reveals CCDC111 mutation associated with high myopia

Myopia is a refractive error of the eye that is prevalent worldwide. The most extreme form, high myopia, is usually associated with other ocular disorders such as retinal detachment, macular degeneration, cataract, and glaucoma, and is one of leading causes of blindness. The etiology is complex and has not been fully elucidated. In this study, we identified a novel missense variant of the CCDC111 gene (NM_152683.2: c.265T > G; p.Y89D) in a high myopia family by exome sequencing. The variant was identified in 4 patients from an additional 270 sporadic high myopia patients, but not found in 270 controls. The amino acid is highly conserved across species, and variants giving rise to amino acid substitutions are predicted to be functionally damaging. The CCDC111 gene was ubiquitously expressed in primary cell cultures from human eye tissue, including corneal epithelial cells, choroidal melanoma cells, scleral fibroblasts, retinal epithelial cells, retinal Müller cells, and lens capsule epithelial cells. In summary, our results suggested that the CCDC111 may be a susceptibility gene for high myopia.     

3q26.31–q29 duplication and 9q34.3 microdeletion associated with omphalocele,ventricular septal defect,abnormal first-trimester maternal serum screening and increased nuchal translucency: Prenatal diagnosis and aCGH characterization

We present prenatal diagnosis and array comparative genomic hybridization characterization of 3q26.31–q29 duplication and 9q34.3 microdeletion in a fetus with omphalocele, ventricular septal defect, increased nuchal translucency, abnormal first-trimester maternal screening and facial dysmorphism with distinct features of the 3q duplication syndrome and Kleefstra syndrome. The 26.61-Mb duplication of 3q26.31–q29 encompasses EPHB3, CLDN1 and CLDN16, and the 972-kb deletion of 9q34.3 encompasses EHMT1. We review the literature of partial trisomy 3q associated with omphalocele and discuss the genotype–phenotype correlation in this case.