Flower induction in apple (Malus domestica Borkh.) is regulated by complex gene networks that involve multiple signal pathways to ensure flower bud formation in the next year, but the molecular determinants of apple flower induction are still unknown. In this research, transcriptomic profiles from differentiating buds allowed us to identify genes potentially involved in signaling pathways that mediate the regulatory mechanisms of flower induction. A hypothetical model for this regulatory mechanism was obtained by analysis of the available transcriptomic data, suggesting that sugar-, hormone- and flowering-related genes, as well as those involved in cell-cycle induction, participated in the apple flower induction process. Sugar levels and metabolism-related gene expression profiles revealed that sucrose is the initiation signal in flower induction. Complex hormone regulatory networks involved in cytokinin (CK), abscisic acid (ABA) and gibberellic acid pathways also induce apple flower formation. CK plays a key role in the regulation of cell formation and differentiation, and in affecting flowering-related gene expression levels during these processes. Meanwhile, ABA levels and ABA-related gene expression levels gradually increased, as did those of sugar metabolism-related genes, in developing buds, indicating that ABA signals regulate apple flower induction by participating in the sugar-mediated flowering pathway. Furthermore, changes in sugar and starch deposition levels in buds can be affected by ABA content and the expression of the genes involved in the ABA signaling pathway. Thus, multiple pathways, which are mainly mediated by crosstalk between sugar and hormone signals, regulate the molecular network involved in bud growth and flower induction in apple trees.

BackgroundA long juvenile period between germination and flowering is a common characteristic among fruit trees, including Malus hupehensis (Pamp.) Rehd., which is an apple rootstock widely used in China. microRNAs (miRNAs) play an important role in the regulation of phase transition and reproductive growth processes.ResultsM. hupehensis RNA libraries, one adult and one juvenile phase, were constructed using tree leaves and underwent high-throughput sequencing. We identified 42 known miRNA families and 172 novel miRNAs. We also identified 127 targets for 25 known miRNA families and 168 targets for 35 unique novel miRNAs using degradome sequencing. The identified miRNA targets were categorized into 58 biological processes, and the 123 targets of known miRNAs were associated with phase transition processes. The KEGG analysis revealed that these targets were involved in starch and sucrose metabolism, and plant hormone signal transduction. Expression profiling of miRNAs and their targets indicated multiple regulatory functions in the phase transition. The higher expression level of mdm-miR156 and lower expression level of mdm-miR172 in the juvenile phase leaves implied that these two small miRNAs regulated the phase transition. mdm-miR160 and miRNA393, which regulate genes involved in auxin signal transduction, could also be involved in controlling this process. The identification of known and novel miRNAs and their targets provides new information on this regulatory process in M. hupehensis, which will contribute to the understanding of miRNA functions during growth, phase transition and reproduction in woody fruit trees.ConclusionsThe combination of sRNA and degradome sequencing can be used to better illustrate the profiling of hormone-regulated miRNAs and miRNA targets involving complex regulatory networks, which will contribute to the understanding of miRNA functions during growth, phase transition and reproductive growth in perennial woody fruit trees.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-1125) contains supplementary material, which is available to authorized users.

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Whole-brain mesoscale mapping of primates has been hindered by large brain size and the relatively low throughput of available microscopy methods. Here, we present an integrative approach that combines primate-optimized tissue sectioning and clearing with ultrahigh-speed, large-scale, volumetric fluorescence microscopy, capable of completing whole-brain imaging of a rhesus monkey at 1 µm × 1 µm × 2.5 µm voxel resolution within 100 hours. A progressive strategy is developed for high-efficiency, long-range tracing of individual axonal fibers through the dataset of hundreds of terabytes, establishing a "Serial sectioning and clearing, 3-dimensional Microscopy, with semi-Automated Reconstruction and Tracing" (SMART) pipeline. This system supports effective connectome-scale mapping of large primates that reveals distinct features of thalamocortical projections of the rhesus monkey brain at the level of individual axonal fibers.

I ntravenous leiomyoma (IVL) is a rare, histologically benign smooth-muscle-cell tumor that occurs only in women. This neoplasm occupies vascular spaces from the intrauterine venules to the systemic veins, including the iliac vein and inferior vena cava (IVC), and it does not invade the tissue. The mass can extend into the right heart chambers and pulmonary arteries. 1,2 Its extrauterine involvement occurs in approximately 30% of cases, and intracardiac extension accounts for about 10%. [3][4][5] This extension of IVL into the right side of the heart is called intracardiac leiomyomatosis (ICL).The diagnosis of ICL can be overlooked. Echocardiography, abdominal ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI) are available for detection and diagnosis. Echocardiography is important in the initial diagnosis of ICL. To our knowledge, the literature about ICL chiefly comprises case reports, and the authors of the few case series have not in general discussed the echocardiographic characteristics and extending pathways of ICL. We retrospectively studied the cases of 7 patients with ICL who underwent successful tumor resection in our hospital. We outlined the echocardiographic characteristics of the tumors and analyzed their clinical features, confirmed the extending pathways by means of CT reports, and studied the surgical and pathologic results. We discuss the echocardiographic diagnosis of ICL and briefly review the pertinent medical literature. Patients and MethodsWe reviewed our hospital's clinical database and identified 7 women who had undergone surgical resection of ICL tumors from January 2003 through July 2012. The echocardiographic images included parasternal, apical, and subcostal views. In addition, M-mode, pulsed and continuous-wave Doppler, and color-flow Doppler images

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Inverse lithography technology (ILT) treats photomask design for microlithography as an inverse mathematical problem. We show how the inverse lithography problem can be addressed as an obstacle reconstruction problem or an extended nonlinear image restoration problem, and then solved by a level set time-dependent model with finite difference schemes. We present explicit detailed formulation of the problem together with the first-order temporal and second-order spatial accurate discretization scheme. Experimental results show the superiority of the proposed level set-based ILT over the mainstream gradient methods.

GRAS genes encode plant-specific transcription factors that play important roles in plant growth and development. However, little is known about the GRAS gene family in apple. In this study, 127 GRAS genes were identified in the apple (Malus domestica Borkh.) genome and named MdGRAS1 to MdGRAS127 according to their chromosomal locations. The chemical characteristics, gene structures and evolutionary relationships of the MdGRAS genes were investigated. The 127 MdGRAS genes could be grouped into eight subfamilies based on their structural features and phylogenetic relationships. Further analysis of gene structures, segmental and tandem duplication, gene phylogeny and tissue-specific expression with ArrayExpress database indicated their diversification in quantity, structure and function. We further examined the expression pattern of MdGRAS genes during apple flower induction with transcriptome sequencing. Eight higher MdGRAS (MdGRAS6, 26, 28, 44, 53, 64, 107, and 122) genes were surfaced. Further quantitative reverse transcription PCR indicated that the candidate eight genes showed distinct expression patterns among different tissues (leaves, stems, flowers, buds, and fruits). The transcription levels of eight genes were also investigated with various flowering related treatments (GA3, 6-BA, and sucrose) and different flowering varieties (Yanfu No. 6 and Nagafu No. 2). They all were affected by flowering-related circumstance and showed different expression level. Changes in response to these hormone or sugar related treatments indicated their potential involvement during apple flower induction. Taken together, our results provide rich resources for studying GRAS genes and their potential clues in genetic improvement of apple flowering, which enriches biological theories of GRAS genes in apple and their involvement in flower induction of fruit trees.