长非编码RNA编码微肽的研究进展

长非编码RNA (long non-coding RNA, lncRNA)是长度超过200 nt的非编码RNA,具有一个或多个短开放阅读框,可编码功能性微肽。这些功能性微肽在各种生物过程中扮演着重要角色,例如Ca2+转运、线粒体代谢、肌细胞融合和细胞衰老等过程。同时,这些生物过程又在机体稳态调控、疾病和癌症的发生与发展、胚胎发育等重要生理过程中起关键作用。因此,研究由lncRNA编码的微肽在生物体的潜在的调控机制,将有助于进一步解析生物体潜在调控过程,并为后续疾病的靶向治疗及动物生长性能的提高提供新的理论依据。本文综述了现阶段lncRNA编码微肽领域的最新研究进展,并对当前微肽在肌肉生理、炎症与免疫、人类常见癌症、胚胎发育等领域的研究进展进行描述与总结,最后简单阐述了lncRNA编码微肽现阶段面临的问题和存在的挑战,以期为后续微肽的深入研究提供科学参考及新思路。     

N‐terminal β‐strand swapping in a consensus‐derived alternative scaffold driven by stabilizing hydrophobic interactions

The crystal structure of an N‐terminal β‐strand‐swapped consensus‐derived tenascin FN3 alternative scaffold has been determined. A comparison with the unswapped structure reveals that the side chain of residue F88 orients differently and packs more tightly with the hydrophobic core of the domain. Dimer formation also results in the burial of a hydrophobic patch on the surface of the domain. Thus, it appears that tighter packing of F88 in the hydrophobic core and burial of surface hydrophobicity provide the driving forces for the N‐terminal β‐strand swapping, leading to the formation of a stable compact dimer. Proteins 2014; 82:1527–1533. © 2014 Wiley Periodicals, Inc.     

Two Novel Susceptibility SNPs for Ischemic Stroke Using Exome Sequencing in Chinese Han Population

Genome-wide association studies (GWAS) of ischemic stroke (IS) have been performed on several cohorts of Caucasian or African population and Japanese, resulting in somewhat inconsistent conclusion. We aimed to identify susceptibility loci for IS by exome sequencing in a Chinese Han population. Exome sequencing was used to screen susceptibility loci among 100 cases and 100 matched controls. Significant SNPs from the first stage were verified in up to 3,554 participants from three hospital-based case–control studies. In the initial exome sequencing analysis, rs10489177 in c1orf156 gene located on chromosome 1q24 (p?<?1?×?10^?8) and rs17118 in XYLB gene located on chromosome 3p21 (p?<?1?×?10^?6) were found to be significantly associated with IS. In the following validation stage, significantly increased odds ratios were observed in individuals with rs10489177 GG (OR?=?2.02, 95 % CI?=?1.35–3.03) or rs17118 AA genotype (OR?=?1.50, 95 % CI?=?1.17–1.91). The rs10489177 GG genotype was associated with significantly increased risk for IS in individuals without hypertension (OR?=?2.78, 95 % CI?=?1.59–4.86) and in individuals without diabetes (OR?=?1.93, 95 % CI?=?1.27–2.94). In contrast, the rs17118 AA genotype may significantly increase the risk for IS, particularly for individuals with hypertension (OR?=?1.73, 95 % CI?=?1.08–2.78) and for individuals without diabetes (OR?=?1.52, 95 % CI?=?1.17–1.98) or non-smoker (OR?=?1.59, 95 % CI?=?1.16–2.19). Collectively, our study identified two novel loci (rs17118 and rs10489177) which were associated with an increased risk for IS in Chinese Han populations. Further studies are needed to confirm these associations in other populations and elucidate the biological mechanisms underlying the observed associations.     

Synthesis and characterization of selective dopamine D2 receptor antagonists. 2. Azaindole,benzofuran, and benzothiophene analogs of L-741,626

A series of indole, 7-azaindole, benzofuran, and benzothiophene compounds have been prepared and evaluated for affinity at D_2-like dopamine receptors. These compounds share structural elements with the classical D_2-like dopamine receptor antagonists haloperidol, N-methylspiperone and benperidol. Two new compounds, 4-(4-iodophenyl)-1-((4-methoxy-1H-indol-3-yl)methyl)piperidin-4-ol (6) and 4-(4-iodophenyl)-1-((5-methoxy-1H-indol-3-yl)methyl)piperidin-4-ol (7), were found to have high affinity to and selectivity for D₂ versus D₃ receptors. Changing the aromatic ring system from an indole to other heteroaromatic ring systems reduced the D₂ binding affinity and the D₂ versus D₃ selectivity.     

Biogeographic variation in temperature sensitivity of decomposition in forest soils

Determining soil carbon (C) responses to rising temperature is critical for projections of the feedbacks between terrestrial ecosystems, C cycle, and climate change. However, the direction and magnitude of this feedback remain highly uncertain due largely to our limited understanding of the spatial heterogeneity of soil C decomposition and its temperature sensitivity. Here we quantified C decomposition and its response to temperature change with an incubation study of soils from 203 sites across tropical to boreal forests in China spanning a wide range of latitudes (18°16′ to 51°37′N) and longitudes (81°01′ to 129°28′E). Mean annual temperature (MAT) and mean annual precipitation primarily explained the biogeographic variation in the decomposition rate and temperature sensitivity of soils: soil C decomposition rate decreased from warm and wet forests to cold and dry forests, while Q_10‐MAT (standardized to the MAT of each site) values displayed the opposite pattern. In contrast, biological factors (i.e. plant productivity and soil bacterial diversity) and soil factors (e.g. clay, pH, and C availability of microbial biomass C and dissolved organic C) played relatively small roles in the biogeographic patterns. Moreover, no significant relationship was found between Q_10‐MAT and soil C quality, challenging the current C quality–temperature hypothesis. Using a single, fixed Q_10‐MAT value (the mean across all forests), as is usually done in model predictions, would bias the estimated soil CO₂ emissions at a temperature increase of 3.0°C. This would lead to overestimation of emissions in warm biomes, underestimation in cold biomes, and likely significant overestimation of overall C release from soil to the atmosphere. Our results highlight that climate‐related biogeographic variation in soil C responses to temperature needs to be included in next‐generation C cycle models to improve predictions of C‐climate feedbacks.     

Effect of Erosion on Productivity in Subtropical Red Soil Hilly Region: A Multi-Scale Spatio-Temporal Study by Simulated Rainfall

The effects of water erosion (including long-term historical erosion and single erosion event) on soil properties and productivity in different farming systems were investigated. A typical sloping cropland with homogeneous soil properties was designed in 2009 and then protected from other external disturbances except natural water erosion. In 2012, this cropland was divided in three equally sized blocks. Three treatments were performed on these blocks with different simulated rainfall intensities and farming methods: (1) high rainfall intensity (1.5 - 1.7 mm min⁻¹), no-tillage operation; (2) low rainfall intensity (0.5 - 0.7 mm min⁻¹), no-tillage operation; and (3) low rainfall intensity, tillage operation. All of the blocks were divided in five equally sized subplots along the slope to characterize the three-year effects of historical erosion quantitatively. Redundancy analysis showed that the effects of long-term historical erosion significantly caused most of the variations in soil productivity in no-tillage and low rainfall erosion intensity systems. The intensities of the simulated rainfall did not exhibit significant effects on soil productivity in no-tillage systems. By contrast, different farming operations induced a statistical difference in soil productivity at the same single erosion intensity. Soil organic carbon (SOC) was the major limiting variable that influenced soil productivity. Most explanations of long-term historical erosion for the variation in soil productivity arose from its sharing with SOC. SOC, total nitrogen, and total phosphorus were found as the regressors of soil productivity because of tillage operation. In general, this study provided strong evidence that single erosion event could also impose significant constraints on soil productivity by integrating with tillage operation, although single erosion is not the dominant effect relative to the long-term historical erosion. Our study demonstrated that an effective management of organic carbon pool should be the preferred option to maintain soil productivity in subtropical red soil hilly region.