Silencing of FABP3 promotes apoptosis and induces mitochondrion impairment in embryonic carcinoma cells

Fatty acid binding protein 3 (FABP3) (also known as H-FABP) is a member of the intracellular lipid-binding protein family, and is mainly expressed in cardiac muscle tissue. The in vivo function of FABP3 is proposed to be in fatty acid metabolism, trafficking, and cell signaling. Our previous study found that FABP3 is highly regulated in patients with ventricular septal defect (VSD), and may play a significant role in the development of human VSD. In the present study, we aimed to investigate the impact of FABP3 knockdown by RNA interference (RNAi) on apoptosis and mitochondrial function of embryonic carcinoma (P19) cells. The results revealed that downregulated FABP3 expression promoted apoptosis, and resulted in mitochondrial deformation, increased mitochondrial membrane potential (MMP), and decreased intracellular ATP synthesis. In addition, the knockdown of FABP3 also led to excess intracellular ROS production. However, there was no obvious influence on the amount of mitochondrial DNA. Collectively, our results indicated that FABP3 knockdown promoted apoptosis and caused mitochondrial dysfunction in P19 cells, which might be responsible for the development of human VSD.     

Slow decomposition of lower order roots: a key mechanism of root carbon and nutrient retention in the soil

Among tree fine roots, the distal small-diameter lateral branches comprising first- and second-order roots lack secondary (wood) development. Therefore, these roots are expected to decompose more rapidly than higher order woody roots. But this prediction has not been tested and may not be correct. Current evidence suggests that lower order roots may decompose more slowly than higher order roots in tree species associated with ectomycorrhizal (EM) fungi because they are preferentially colonized by fungi and encased by a fungal sheath rich in chitin (a recalcitrant compound). In trees associated with arbuscular mycorrhizal (AM) fungi, lower order roots do not form fungal sheaths, but they may have poorer C quality, e.g. lower concentrations of soluble carbohydrates and higher concentrations of acid-insolubles than higher order roots, thus may decompose more slowly. In addition, litter with high concentrations of acid insolubles decomposes more slowly under higher N concentrations (such as lower order roots). Therefore, we propose that in both AM and EM trees, lower order roots decompose more slowly than higher order roots due to the combination of poor C quality and high N concentrations. To test this hypothesis, we examined decomposition of the first six root orders in Fraxinus mandshurica (an AM species) and Larix gmelinii (an EM species) using litterbag method in northeastern China. We found that lower order roots of both species decomposed more slowly than higher order roots, and this pattern appears to be associated mainly with initial C quality and N concentrations. Because these lower order roots have short life spans and thus dominate root mortality, their slow decomposition implies that a substantial fraction of the stable soil organic matter pool is derived from these lower order roots, at least in the two species we studied.     

Precise mapping of a quantitative trait locus interval for spike length and grain weight in bread wheat (Triticum aestivum L.)

The spike characteristics length, spikelet density and fertile floret number are related yield components and are important in cereal improvement. QSpl.nau-2D is a major quantitative trait locus controlling spike length (SPL) detected in the recombinant inbred line population developed by crossing wheat (Triticum aestivum) cultivars Nanda2419 with Wangshuibai. In this study, to validate its genetic effect and determine its precise location, QSpl.nau-2D’s near-isogenic line (NIL) was developed using Mianyang99-323 as the recurrent parent through marker-assisted selection. Field trials showed that the NIL not only had significantly longer spikes on average than the recurrent parent but also had significantly higher grain weight, but did not differ in spikelet number and kernel number per spike. In the F2 population derived from a cross of the NIL with Mianyang99-323, QSpl.nau-2D functioned like a single gene and conditioned the SPL in a partially dominant manner, and was thus designated as HL1 (for head length). To precisely map HL1, 89 recombinants, consisting of 11 genotypes, were identified in the NIL-derived F2 population of 674 plants by using markers in the Xwmc25–Xgpw4080 interval. Phenotyping these lines showed that the introduction of a 0.9-cM interval flanked by Xcfd53 and DG371 in Nanda2419 resulted in longer spikes and a higher grain weight in the NIL. The availability of markers closely linked to HL1 could facilitate its use in breeding programs.     

Environmental risk assessment of manganese and its associated heavy metals in a stream impacted by manganese mining in South China

In South China, high manganese content in the drinking water source influenced by upstream manganese mine drainage has become a major concern. To investigate the extent of metal pollution and environmental risk in upstream sediments and native aquatic macrophytes, a study was conducted on a manganese mining-impacted river named the Heishui River. The results indicated that streambed sediments collected were polluted by Mn and other metals with the highest contents of Mn 43349.4 mg kg^?1, Pb 128.6 mg kg^?1, Zn 502.9 mg kg^?1, and Cu 107.2 mg kg^?1. The level of Mn in all sediments was higher than the consensus-based Probable Effect Concentration, indicating that adverse effects on sediment-dwelling organisms were likely to occur frequently. Among the studied metals, Mn had the highest bioavailability and ecological risk, followed by Zn. Native aquatic macrophytes accumulate large amounts of the studied metals. A significantly positive correlation was found between exchangeable fractions of the studied metals in sediments and in aquatic macrophytes. The risk assessment code showed the following risk levels of metals in sediments in descending order: Mn > Zn > Cu > Pb. In conclusion, the river impacted by manganese mining drainage poses a high risk to both the local ecosystem and downstream drinking water.     

Theoretical Insights into Catalytic Mechanism of Protein Arginine Methyltransferase 1

Protein arginine methyltransferase 1 (PRMT1), the major arginine asymmetric dimethylation enzyme in mammals, is emerging as a potential drug target for cancer and cardiovascular disease. Understanding the catalytic mechanism of PRMT1 will facilitate inhibitor design. However, detailed mechanisms of the methyl transfer process and substrate deprotonation of PRMT1 remain unclear. In this study, we present a theoretical study on PRMT1 catalyzed arginine dimethylation by employing molecular dynamics (MD) simulation and quantum mechanics/molecular mechanics (QM/MM) calculation. Ternary complex models, composed of PRMT1, peptide substrate, and S-adenosyl-methionine (AdoMet) as cofactor, were constructed and verified by 30-ns MD simulation. The snapshots selected from the MD trajectory were applied for the QM/MM calculation. The typical S_N2-favored transition states of the first and second methyl transfers were identified from the potential energy profile. Deprotonation of substrate arginine occurs immediately after methyl transfer, and the carboxylate group of E144 acts as proton acceptor. Furthermore, natural bond orbital analysis and electrostatic potential calculation showed that E144 facilitates the charge redistribution during the reaction and reduces the energy barrier. In this study, we propose the detailed mechanism of PRMT1-catalyzed asymmetric dimethylation, which increases insight on the small-molecule effectors design, and enables further investigations into the physiological function of this family.     

Identification and characterization of FHL3 as a novel angiogenin-binding partner

Angiogenin (Ang) is known to induce cell proliferation and inhibit apoptosis by cellular signaling pathways and by direct nuclear functions of Ang, but the mechanism of action for Ang is not yet clear. The aim of present study was to identify novel binding partner of Ang and to explore the underlying mechanism. With the use of yeast two-hybrid screening system, Ang was used as the bait to screen human fetal hepatic cDNA library for interacting proteins. Four and a half LIM domains 3 (FHL3) was identified as a novel Ang binding partner. The interaction between Ang and the full length FHL3 was further confirmed by yeast two-hybrid assay, co-immunoprecipitation and GST pull-down assays. Furthermore, FHL3 was required for Ang-mediated HeLa cell proliferation and nuclear translocation of Ang. These findings suggest that the interaction between Ang and FHL3 may provide some clues to the mechanisms of Ang-regulated cell growth and apoptosis.     

Melatonin Regulates the Viability and Differentiation of Rat Midbrain Neural Stem Cells

(1) Neurogenesis driven by neural stem cells (NSCs) is regulated by physiological and pathological factors. Melatonin (MT) has profound neurotrophic and neuroprotective effects. Hence, we studied the role of MT in regulating the viability and differentiation of NSCs derived from rat ventral midbrain. (2) NSCs were isolated from the rat ventral midbrain. The viability of NSCs was determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-ulfophenyl)-2H-tetrazolium assay. The differentiation of NSCs was examined by analyzing the expression of the neural markers, MT receptors, brain derived neurotropic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) with semi-quantitative RT-PCR, immunofluorescence cytochemistry, and Western blot. (3) Our results showed that MT could promote the viability of NSCs. In addition, MT could significantly elevate the mRNA and protein levels of tyroxine hydroxylase (TH), a marker of dopaminergic neurons, and decrease the expression of the astrocytes maker glial fibrillary acidic protein (GFAP). MT also increased the production of BDNF and GDNF in the cultured NSCs. Meanwhile, we first found that two subtypes of MT receptors, MT1 and MT2, were expressed in the ventral midbrain NSCs. (4) These results demonstrated that MT could induce NSCs to differentiate into dopaminergic neurons and decrease astrocyte production. These findings also suggest that MT could offer a beneficial tool in guiding directional differentiation of NSCs.     

粘合材料及其在生物医学中的应用：进展与展望

粘合材料作为一种重要的辅助材料,在工业包装、海洋工程以及生物医药等多个领域都有广泛的应用需求。天然存在的粘合剂如贻贝足丝粘合蛋白等具有良好的生物相容性和生物可降解性,但因其来源受限及在生理环境下较弱的粘合性能,因此在生物医药领域的应用受到了限制。从自然生物的粘合现象中汲取灵感,各种利用化学或生物合成方法制备的仿生粘合材料应运而生,针对生物医药领域的特定需求,一些新兴粘合材料在生物相容性、生物可降解性以及组织粘附等方面都表现出在医药领域应用的潜力。展望未来,受自然粘合材料兼具环境响应、自我再生和自修复等特征的启迪,各种生物灵感和生物仿生粘合材料的开发势必是未来的发展热点,而合成生物学技术为创建具有上述特征的活体粘合材料提供了新的可能。     

青海锡铁山矿区铅、锌的植物地球化学特征及其与矿的关系

 通过青海锡铁山铅、锌矿区植物群落和植物中铅,锌含量特征的调查研究表明：该区植被为荒漠植被类型。矿带上的植物群落与非矿带上的相比较,群落中种属数目更少,覆盖度更低,植物生长更低矮。植物灰分中的锌含量(平均)为125.9—1144ppm。膜果麻黄(Ephedra przewalskii)含量最高,变化范围最大,为86.11—5871.88ppm。植物中的铅含量为31.32—1129.6ppm。黑柴(Sympegma regelii)含量较高,变化最大,平均为746ppm,极值为14.3—5561.70ppm。在矿带上含量最高,非矿带对照区含量最低。植物及其生长的土壤中金属元素含量之间的关系,无论是铅还是锌含量都有很好的线性关系。膜果麻黄、黑柴、优若藜(Eurotia ceratoides)和中亚紫菀木(Asterothamnus centrali-asiaticus)等植物相关系数均达显著相关水平(α≤0.05)。 这在植物地球化学勘探上是非常有用的。例如中亚紫菀木和琵琶柴(Reaumuria soongorica)中铅的植物地球化学异常,准确地圈出了铅、锌矿的位置,衬度高,异常范围与矿化区基本吻合。