基于景观尺度下的鄱阳湖湿地浅层土有机碳的空间特征

湿地土壤有机碳研究是全球碳循环研究的基础性工作, 对于准确评估湿地固碳增汇和全球温室气体减排都具有重要意义。以鄱阳湖国家自然保护区为研究区域, 选择六种景观类型(湿地洲滩景观包括受人工控制的碟形湖泊常湖池、半人工控制的碟形湖泊蚌湖、不受人工控制的洲滩前缘泗洲头以及岗地景观包括林地、田地和菜地), 湿地洲滩景观在各1 m高程(泗洲头和蚌湖采样高程10-17 m, 常湖池采样高程12-17 m)内的浅土壤采取3个土壤样品, 岗地景观浅层土壤各采取3个土壤样品, 分析浅层土壤有机碳含量。结果表明, 鄱阳湖不同景观类型的浅层土壤有机碳含量差异性显著。湿地洲滩浅层土壤(特别是0-10 cm土层)的有机碳随高程梯度变化呈现倒U型变化, 即低海拔与高海拔土壤有机碳的含量较中海拔土壤有机碳的含量低, 泗洲头洲滩土层0-10 cm的有机碳含量最高值出现在13-14 m高程, 其中0-10 cm土层的土壤有机碳含量变化值为1.56-12.29 g·kg-1, 10-20 cm土层的土壤有机碳含量变化值为0.96-8.19 g·kg-1; 蚌湖洲滩土层0-10 cm的有机碳含量最高值出现在14-15 m高程, 其中0-10 cm土层的土壤有机碳含量变化值为6.36-23.32 g·kg-1, 10-20 cm土层的土壤有机碳含量变化值为4.14-8.88 g·kg-1; 常湖池洲滩土层0-10 cm的有机碳含量最高值出现在16-17 m高程, 其中0-10 cm土层的土壤有机碳含量变化值为6.51-18.91 g·kg-1, 10-20 cm土层的土壤有机碳含量变化值为3.83-10.05 g·kg-1。岗地浅层土壤有机碳(特别是0-10 cm土层)田地的土壤有机碳含量最高, 菜地土壤有机碳含量最低。比较六种景观类型的浅层土壤有机碳含量, 泗洲头洲滩浅层土壤有机碳含量最低, 蚌湖洲滩浅层土壤有机碳含量最高。六种景观类型的浅层土壤有机碳含量呈现一致的现象是土层0-10 cm的机碳含量明显高于土层10-20 cm的有机碳含量, 说明鄱阳湖国家自然保护区内土壤有机碳含量主要富集在土壤浅层的特征。土壤pH值对湿地土壤有机碳呈显著负相关性, 而土壤含水量、地上部分生物量与土壤有机碳呈显著正相关性。     

Changes in Histamine Receptors (H1, H2, and H3) Expression in Rat Medial Vestibular Nucleus and Flocculus after Unilateral Labyrinthectomy: Histamine Receptors in Vestibular Compensation

Vestibular compensation is the process of behavioral recovery following peripheral vestibular lesion. In clinics, the histaminergic medicine is the most widely prescribed for the treatment of vertigo and motion sickness, however, the molecular mechanisms by which histamine modulates vestibular function remain unclear. During recovery from the lesion, the modulation of histamine receptors in the medial vestibular nucleus (MVN) and the flocculus may play an important role. Here with the means of quantitative real-time PCR, western blotting and immunohistochemistry, we studied the expression of histamine receptors (H1, H2, and H3) in the bilateral MVN and the flocculus of rats on the 1st, 3rd, and 7th day following unilateral labyrinthectomy (UL). Our results have shown that on the ipsi-lesional flocculus the H1, H2 and H3 receptors mRNA and the protein increased significantly on the 1st and 3rd day, with compare of sham controls and as well the contralateral side of UL. However, on the 7th day after UL, this expression returned to basal levels. Furthermore, elevated mRNA and protein levels of H1, H2 and H3 receptors were observed in the ipsi-lesional MVN on the 1st day after UL compared with sham controls and as well the contralateral side of UL. However, this asymmetric expression was absent by the 3rd post-UL. Our findings suggest that the upregulation of histamine receptors in the MVN and the flocculus may contribute to rebalancing the spontaneous discharge in bilateral MVN neurons during vestibular compensation.     

White-rot fungus <Emphasis Type="Italic">Ganoderma</Emphasis> sp.En3 had a strong ability to decolorize and tolerate the anthraquinone,indigo and triphenylmethane dye with high concentrations

The ability of the white-rot fungus Ganoderma sp.En3 to decolorize different kinds of dyes widely applied in the textile and dyeing industry, including the anthraquinone dye Remazol Brilliant Blue R (RBBR), indigo dye indigo carmine and triphenylmethane dye methyl green, was evaluated in this study. Ganoderma sp.En3 had a strong capability of decolorizing high concentrations of RBBR, indigo carmine and methyl green. Obvious reduction of Chemical Oxygen Demand was observed after decolorization of different dyes. Ganoderma sp.En3 had a strong ability to tolerate RBBR, indigo carmine and methyl green with high concentrations. High concentrations of RBBR, indigo carmine and methyl green could also be efficiently decolorized by the crude enzyme of Ganoderma sp.En3. Different redox mediators such as syringaldehyde, acetosyringone and acetovanillone could enhance the decolorization capability for higher concentration of indigo carmine and methyl green. Different metal ions had little effect on the ability of the crude enzyme to decolorize indigo carmine and methyl green. Our study suggested that Ganoderma sp.En3 had a strong capability for decolorizing and tolerating high concentrations of different types of dyes such as RBBR, indigo carmine and methyl green.     

A Scheme to Optimize Flow Routing and Polling Switch Selection of Software Defined Networks

This paper aims at minimizing the communication cost for collecting flow information in Software Defined Networks (SDN). Since flow-based information collecting method requires too much communication cost, and switch-based method proposed recently cannot benefit from controlling flow routing, jointly optimize flow routing and polling switch selection is proposed to reduce the communication cost. To this end, joint optimization problem is formulated as an Integer Linear Programming (ILP) model firstly. Since the ILP model is intractable in large size network, we also design an optimal algorithm for the multi-rooted tree topology and an efficient heuristic algorithm for general topology. According to extensive simulations, it is found that our method can save up to 55.76% communication cost compared with the state-of-the-art switch-based scheme.     

Growth factors stimulate kidney proximal tubule cell migration independent of augmented tyrosine phosphorylation of focal adhesion kinase

Migration of human proximal tubule cells (HKC-5) was stimulated by epidermal growth factor (EGF), hepatocyte growth factor (HGF), and insulin-like growth factor-1 (IGF-1). Integrin signaling via phosphorylation of focal adhesion kinase (FAK) appears to play a central role in cell migration. Once stimulated, FAK undergoes autophosphorylation at tyrosine (Y) 397, followed by phosphorylation of several sites including Y576/Y577 which increases FAK's kinase activity, as well as at Y407, Y861, and Y925. EGF, HGF, and IGF-1 stimulate FAK phosphorylation in various cells. We showed that endothelin stimulated phosphorylation of Y397 in fibroblasts but not HKC-5 cells. After EGF stimulation, HKC-5 cells showed no change in tyrosine phosphorylation at FAK Y397, 407, 576, 861, or 925. Similarly, HGF and IGF-1 did not stimulate the phosphorylation of FAK Y397 in HKC-5 cells. Further, after inhibition of FAK expression by siRNA, cell migration was similar to cells treated with non-target siRNA and responded to EGF with increased migration. Thus, in proximal tubule cells, stimulation of cell migration by growth factors was independent of augmented FAK tyrosine phosphorylation.     

A general two-step strategy to synthesize lariat RNAs

We describe a general and efficient two-step strategy for lariat RNA synthesis. In the first step, a deoxyribozyme synthesizes 2',5'-branched RNA. In the second step, T4 RNA ligase closes the loop that completes the lariat. The loop-closure reaction can form either a natural or unnatural lariat isomer, depending on which of the two 3'-termini of the branched RNA reacts with the lone 5'-end. We demonstrate two approaches to control formation of either lariat isomer. In conjunction with other routes for lariat RNA synthesis, the two-step strategy described here will facilitate biochemical studies that require lariat RNAs of varying nucleotide sequence.     

Pluripotency-associated miR-290/302 family of microRNAs promote the dismantling of naive pluripotency

The molecular mechanism controlling the dismantling of naive pluripotency is poorly understood. Here we show that microRNAs (miRNAs) have important roles during naive to primed pluripotency transition. Dgcr8^−/− embryonic stem cells (ESCs) failed to completely silence the naive pluripotency program, as well as to establish the primed pluripotency program during differentiation. miRNA profiling revealed that expression levels of a large number of miRNAs changed dynamically and rapidly during naive to primed pluripotency transition. Furthermore, a miRNA screen identified numerous miRNAs promoting naive to primed pluripotency transition. Unexpectedly, multiple miRNAs from miR-290 and miR-302 clusters, previously shown as pluripotency-promoting miRNAs, demonstrated the strongest effects in silencing naive pluripotency. Knockout of both miR-290 and miR-302 clusters but not either alone blocked the silencing of naive pluripotency program. Mechanistically, the miR-290/302 family of miRNAs may facilitate the exit of naive pluripotency in part by promoting the activity of MEK pathway and through directly repressing Akt1. Our study reveals miRNAs as an important class of regulators potentiating ESCs to transition from naive to primed pluripotency, and uncovers context-dependent functions of the miR-290/302 family of miRNAs at different developmental stages.