Phytohormones play crucial roles in fruit set regulation and development. Here, gibberellins (GA4+7), but not GA3, induced pear parthenocarpy. To systematically investigate the changes upon GA4+7 induced pear parthenocarpy, dynamic changes in histology, hormone and transcript levels were observed and identified in unpollinated, pollinated and GA4+7-treated ovaries. Mesocarp cells continued developing in both GA4+7-treated and pollinated ovaries. In unpollinated ovaries, mesocarp cells stopped developing 14 days after anthesis. During fruit set process, GA4+7, but not GA1+3, increased after pollination. Abscisic acid (ABA) accumulation was significantly repressed by GA4+7 or pollination, but under unpollinated conditions, ABA was produced in large quantities. Moreover, indole-3-acetic acid biosynthesis was not induced by GA4+7 or pollination treatments. Details of this GA–auxin–ABA cross-linked gene network were determined by a comparative transcriptome analysis. The indole-3-acetic acid transport-related genes, mainly auxin efflux carrier component genes, were induced in both GA4+7-treated and pollinated ovaries. ABA biosynthetic genes of the 9-cis-epoxycarotenoid dioxygenase family were repressed by GA4+7 and pollination. Moreover, directly related genes in the downstream parthenocarpy network involved in cell division and expansion (upregulated), and MADS-box family genes (downregulated), were also identified. Thus, a model of GA-induced hormonal balance and its effects on parthenocarpy were established.

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Stromal cell-derived factor-1 is a chemoattractant produced by bone marrow stromal cell lines. It is recognized as a critical factor in the immune and central nervous systems (CNSs) as well as exerting a role in cancer. SDF-1 activates two G protein-coupled receptors, CXCR4 and CXCR7; these are expressed in both developing and mature CNSs and participate in multiple physiological and pathological events, e.g., inflammatory response, neurogenesis, angiogenesis, hematopoiesis, cancer metastasis, and HIV infection. After an ischemic stroke, SDF-1 levels robustly increase in the penumbra regions and participate in adult neural functional repair. Here we will review recent findings about SDF-1 and its receptor, analyse their functions in neurogeneration after brain ischemic injury: i.e., how the system promotes the proliferation, differentiation and migration of neural precursor cells and mediates axonal elongation and branching.

Homogeneous assemblies of the model peptides at interfaces have been achieved and observed with scanning tunneling microscopy. The dependence of the observed brightness in STM images is analyzed, and the correlation with the peptide residues is proposed. We have also investigated the conformational dynamics of the peptide assemblies adsorbed on a graphene sheet by performing all-atom molecular dynamic simulations in water at 300 K. The simulation results of the two peptide assemblies on graphite surfaces show that R(4)G(4)H(8) and F(4)G(4)H(8) peptide assemblies are mostly in β-sheet structure, and the interaction energy of the four different residues with graphite surfaces follows the order of Phe > His > Arg > Gly, consistent with their brightness contrasts in STM images. The insight on the distribution of residue moieties in the peptide assemblies could provide beneficial venues for studying peptide-based interfacial processes such as site-specific interactions between molecular species with peptides.

A universal photochemical method has been established for the immobilization of intact carbohydrates and their analogues, and for the fabrication of carbohydrate microarrays. The method features the use of perfluorophenyl azide (PFPA)-modified substrates and the photochemical reaction of surface azido groups with printed carbohydrates. Various aldoses, ketoses, non-reducing sugars such as alditols and their derivatives can be directly arrayed on the PFPA-modified chips. The lectin-recognition ability of arrayed mannose, glucose and their oligoand polysaccharides were confirmed using surface plasmon resonance imaging and laser-induced fluorescence imaging.

Parthenocarpy, the production of seedless fruit without fertilization, has a variety of valuable qualities, especially for self-incompatible species, such as pear. To explore whether melatonin (MT) induces parthenocarpy, we used ‘Starkrimson’ pear as a material for morphological observations. According to our results, exogenous MT promoted the expansion and division of the mesocarp cells in a manner similar to hand pollination. However, the seeds of exogenous MT-treated fruit were undeveloped and aborted later in the fruit-setting stage. To further investigate how MT induced parthenocarpy, we studied changes of related hormones in the ovaries and found that MT significantly increased the contents of the gibberellins (GAs) GA3 and GA4. Thus, paclobutrazol (PAC), a GA-biosynthesis inhibitor, was used to study the relationship between GAs and MT. In addition, spraying MT after treatment with PAC did not increase GA content nor lead to parthenocarpy. Through a transcriptome analysis, we discovered that MT can cause significant upregulation of PbGA20ox and downregulation of PbGA2ox. However, no significant difference was observed in PbGA2ox compared with the control after PAC and MT applications. Thus, MT induces parthenocarpy by promoting GA biosynthesis along with cell division and mesocarp expansion in pear.

Parthenocarpy, the productions of seedless fruit without pollination or fertilization, is a potentially desirable trait in many commercially grown fruits, especially in pear, which is self-incompatible. Phytohormones play important roles in fruit set, a process crucial for parthenocarpy. In this study, 2,4-dichlorophenoxyacetic acid (2,4-D), an artificially synthesized plant growth regulator with functions similar to auxin, was found to induce parthenocarpy in pear. Histological observations revealed that 2,4-D promoted cell division and expansion, which increased cortex thickness, but the effect was weakened by paclobutrazol (PAC), a gibberellin (GA) biosynthesis inhibitor. Phenotypic differences in pear may therefore be due to different GA contents. Hormone testing indicated that 2,4-D mainly induced the production of bioactive GA , rather than GA Three key oxidase genes function in the GA biosynthetic pathway: GA20ox, GA3ox and GA2ox. In a pear group treated with only 2,4-D, PbGA20ox2-like and PbGA3ox-1 were significantly upregulated. When treated with 2,4-D supplemented with PAC, however, expression levels of these genes were significantly downregulated. Additionally, PbGA2ox1-like and PbGA2ox2-like expression levels were significantly downregulated in pear treated with either 2,4-D only or 2,4-D supplemented with PAC. We thus hypothesize that 2,4-D can induce parthenocarpy by enhancing GA biosynthesis.

Various types of knowledge and features have been explored for level set-based segmentation. On the ground, the prior knowledge and carefully-designed features perform well to identify the foregroundbackground contrast, which improves the performance of the segmentation method for complicated and distorted data. However, this is not the case for underwater environments, since the features available on the ground are not suitable for challenging underwater environments. Thus, underwater image segmentation currently lags behind ground-based segmentation. In this paper, novel cues and a suitable model formulation for object segmentation from underwater images are proposed. We consider the special haze effect over underwater images and extract an informative feature (transmission feature) from haze condensation. The saliency feature is also used for underwater object segmentation. Consequently, in our method, the objectbackground difference can be presented by these features on two levels, i.e., the edge-level transmission and region-level saliency features. These two types of features are integrated into a unified level set formulation to propose a solution that handles the challenging issues in underwater object segmentation. The experimental comparisons of our method with other methods comprehensively demonstrate the satisfactory performance of our method.