microRNAs（miRNAs）是广泛存在于哺乳动物中的一种微小、非编码RNA，可以通过靶向吸附调节下游基因的表达，参与多种生物学过程。虽然关于 miRNAs 调控哺乳动物毛色的研究取得了一定的成果，但其调控网络尚不完善，仍需要不断深入研究。前期测序发现，miR-370-5p在白色绵羊皮肤中的表达水平显著高于黑色绵羊，推测其可能参与绵羊皮肤黑色素生成。本研究以绵羊黑色素细胞为研究对象，探究miR-370-5p在绵羊黑色素细胞中的作用。表型检测发现，高表达的miR-370-5p可以显著抑制（P=0.001）酪氨酸酶活性，从而显著降低（P<0.001）黑色素的产生；CCK 8实验检测发现，黑色素细胞转染miR-370-5p后的第4天至第5天，细胞的增殖速率显著降低（P<0.01）。靶基因预测发现，丝裂原活化蛋白激酶8（Mitogen-activated protein kinases, MAP3K8）的3'非翻译区（Untranslated Region, UTR）存在miR-370-5p的靶向结合位点，推测两者可能存在靶向调控关系。双荧光素酶报告载体实验结果显示，miR-370-5p可以靶向吸附MAP3K8-3’UTR。原位杂交实验显示，MAP3K8广泛表达于黑素细胞的细胞质。定量RT-PCR和Western blot结果显示，miR-370-5p显著抑制（P<0.01）MAP3K8的表达。以上结果表明，miR-370-5p可以靶向结合MAP3K8-3’UTR，抑制其表达。siRNA干扰结果显示，黑素细胞中干扰MAP3K8的表达可以显著抑制（P<0.01）细胞增殖，降低（P<0.001）黑色素生成，影响趋势与过表达miR-370-5p一致。靶基因拯救实验结果显示，黑色素细胞中共转染miR-370-5p和MAP3K8-cDNA（含有miR-370-5p靶向结合位点）载体，可以显著上调（P≤0.001）MAP3K8的表达，显著促进细胞增殖（P<0.001）和黑色素产生（P<0.01）。以上结果表明， miR-370-5p通过靶向抑制MAP3K8表达，抑制绵羊黑色素细胞增殖、降低黑色素产量。本研究通过miRNA过表达探明了miR-370-5p对黑色素细胞增殖、酪氨酸酶活性及黑色素产量的影响；通过靶基因干扰、拯救实验解析了miR-370-5p抑制黑色素细胞增殖、酪氨酸酶活性及黑色素生成的分子机制，有助于丰富miRNAs参与毛色形成的调控机制，为后续毛用动物毛色改良提供参考。

之前研究表明活性氧（reactive oxygen species，ROS）在棉铃虫滞育蛹脑中通过调节独特的胰岛素信号通路转导机制来促进滞育。然而，滞育蛹脑中ROS的来源及调控滞育的机制尚不清楚。本研究的结果显示，滞育蛹脑中积累了高水平的线粒体ROS和总ROS，说明线粒体是滞育蛹脑中ROS的主要来源。另外，注射葡萄糖代谢抑制剂2-脱氧-D-葡萄糖可通过提高非滞育蛹脑中线粒体ROS的水平进而延迟蛹的发育。注射代谢物混合物到滞育蛹中可以降低线粒体ROS的水平进而逆转滞育的进程。进一步的研究显示，线粒体ROS可以激活HSP60的表达和活性，进而促进HSP60/Lon复合物的稳定性，从而降解线粒体转录因子A和降低线粒体活性或生成。因此，本研究阐明了ROS通过降低线粒体活性而促进滞育或寿命延长的有益作用。

Sucrose synthases (SUS) are a family of enzymes that play pivotal roles in carbon partitioning, sink strength and plant development.  A total of 11 SUS genes have been identified in the genome of Malus domestica (MdSUSs), and phylogenetic analysis revealed that the MdSUS genes were divided into three groups, named as SUS I, SUS II and SUS III, respectively.  The SUS I and SUS III groups included four homologs each, whereas the SUS II group contained three homologs.  SUS genes in the same group showed similar structural characteristics, such as exon number, size and length distribution.  After assessing four different tissues, MdSUS1s and MdSUS2.1 showed the highest expression in fruit, whereas MdSUS2.2/2.3 and MdSUS3s exhibit the highest expression in shoot tips.  Most MdSUSs showed decreased expression during fruit development, similar to SUS enzyme activity, but both MdSUS2.1 and MdSUS1.4 displayed opposite expression profiles.  These results suggest that different MdSUS genes might play distinct roles in the sink-source sugar cycle and sugar utilization in apple sink tissues.

Heat stress seriously affects wheat production in many regions of the world.  At present, heat tolerance research remains one of the least understood fields in wheat genetics and breeding and there is a lack of effective methods to quantify heat stress and heat tolerance in different wheat cultivars.  The objective of this study was to use various wheat cultivars to evaluate stress intensity (δ) and a new method for quantification of heat tolerance and compare this technique with three other currently utilized methods.  This new parameter for heat tolerance quantification is referred to as the heat tolerance index (HTI) and is an indicator of both yield potential and yield stability.  Heat treatments were applied in a controlled setting when anthesis had been reached for 80% of the wheat.  The stress intensity evaluation indicated heat shock was the main factor associated with kernel weight reduction while grain yield reduction was mainly associated with chronic high temperature.  The methods evaluation showed that a temperature difference of 5°C from natural temperatures was a suitable heat treatment to compare to the untreated controls.  HTI was positively correlated with yield under heat stress (r=0.8657, δ₂₀₁₀=0.15, in 2009–2010; r=0.8418, δ₂₀₁₁=0.20, in 2010–2011; P<0.01), and negatively correlated with yield reduction rate (r=–0.8344, in 2009–2010; r=–0.7158, in 2010–2011; P<0.01).  The results of this study validated the use of HTI and temperature difference control for quantifying wheat heat tolerance that included the yield potential and the stability of different wheat cultivars under heat stress.  Additionally, 10 wheat cultivars showed high HTI and should be further tested for their heat confirming characteristics for use in wheat heat tolerance breeding.

    A survey of the population densities of rice planthoppers is important for forecasting decisions and efficient control. Traditional manual surveying of rice planthoppers is time-consuming, fatiguing, and subjective. A new three-layer detection method was proposed to detect and identify white-backed planthoppers (WBPHs, Sogatella furcifera (Horváth)) and their developmental stages using image processing. In the first two detection layers, we used an AdaBoost classifier that was trained on a histogram of oriented gradient (HOG) features and a support vector machine (SVM) classifier that was trained on Gabor and Local Binary Pattern (LBP) features to detect WBPHs and remove impurities. We achieved a detection rate of 85.6% and a false detection rate of 10.2%. In the third detection layer, a SVM classifier that was trained on the HOG features was used to identify the different developmental stages of the WBPHs, and we achieved an identification rate of 73.1%, a false identification rate of 23.3%, and a 5.6% false detection rate for the images without WBPHs. The proposed three-layer detection method is feasible and effective for the identification of different developmental stages of planthoppers on rice plants in paddy fields.

Long-chain acyl-Coenzyme A (CoA) synthetases (LACSs) catalyze the formation of long-chain acyl-CoA, and play important roles in fatty acid metabolism including phospholipids, triacylglycerol (TAG) biosynthesis and fatty acid β-oxidation. Here, we report the characterization of a LACS gene from Brassica napus. It is highly homologous to Arabidopsis LACS4 and thus designated as BnLACS4. The cloned gene BnLACS4 could complement a LACS-deficient yeast strain YB525. It is mainly expressed in flowers and developing seeds where lipid biosynthesis is at high rate in Brassica napus. When transiently expressed in tobacco leaves, BnLACS4 is localized in endoplasmic reticulum (ER), the common site for eukaryotic pathway of lipid biosynthesis. Expression of BnLACS4 in the yeast strain pep4 increased its lipid content. Taken together, our results suggest that BnLACS4 may be involved in lipid biosynthesis in B. napus.

MicroRNAs (miRNAs), which post-transcriptionally regulate gene expression by binding to the 3´ untranslated region of mRNAs to either inhibit or enhance translation, are involved in diverse biological processes. The use of high-throughput Solexa sequencing plays important roles in the discovery of miRNAs. In this study, we used high-throughput Solexa sequencing to identify novel duck miRNAs and compare the miRNA expression profiles in laying and non-laying duck ovaries. Using a bioinformatic analysis, we discovered 86 potential duck miRNAs similar to known chicken miRNAs and 43 unique sequences that matched known miRNAs of other species. We also found that miRNA variations and isoforms were widespread in our two RNA libraries, with most of the variations occurring in the 3´ region of the miRNAs. Furthermore, we detected 55 miRNAs that exhibited significant expression differences between laying and non-laying ducks. Gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses of the potential targets of the differentially expressed miRNAs indicated these miRNAs may play key roles in the egg laying process. Finally, we confirmed the differential expression of 5 miRNAs in the laying and non-laying samples by qRT-PCR. Cumulatively, our work provides the first look at the miRNA expression profile of the duck ovary and provides novel insight into the roles of miRNAs in egg laying and reproduction.