Role of Scrib and Dlg in anterior-posterior patterning of the follicular epithelium during Drosophila oogenesis

<p>Abstract</p> <p>Background</p> <p>Proper patterning of the follicle cell epithelium over the egg chamber is essential for the <it>Drosophila </it>egg development. Differentiation of the epithelium into several distinct cell types along the anterior-posterior axis requires coordinated activities of multiple signaling pathways. Previously, we reported that <it>lethal(2)giant larvae </it>(<it>lgl</it>), a <it>Drosophila </it>tumor suppressor gene, is required in the follicle cells for the posterior follicle cell (PFC) fate induction at mid-oogenesis. Here we explore the role of another two tumor suppressor genes, <it>scribble </it>(<it>scrib</it>) and <it>discs large </it>(<it>dlg</it>), in the epithelial patterning.</p> <p>Results</p> <p>We found that removal of <it>scrib </it>or <it>dlg </it>function from the follicle cells at posterior terminal of the egg chamber causes a complete loss of the PFC fate. Aberrant specification and differentiation of the PFCs in the mosaic clones can be ascribed to defects in coordinated activation of the EGFR, JAK and Notch signaling pathways in the multilayered cells. Meanwhile, the clonal analysis revealed that loss-of-function mutations in <it>scrib/dlg </it>at the anterior domains result in a partially penetrant phenotype of defective induction of the stretched and centripetal cell fate, whereas specification of the border cell fate can still occur in the most anterior region of the mutant clones. Further, we showed that <it>scrib </it>genetically interacts with <it>dlg </it>in regulating posterior patterning of the epithelium.</p> <p>Conclusion</p> <p>In this study we provide evidence that <it>scrib </it>and <it>dlg </it>function differentially in anterior and posterior patterning of the follicular epithelium at oogenesis. Further genetic analysis indicates that <it>scrib </it>and <it>dlg </it>act in a common pathway to regulate PFC fate induction. This study may open another window for elucidating role of <it>scrib/dlg </it>in controlling epithelial polarity and cell proliferation during development.</p

Potential of Core-Collapse Supernova Neutrino Detection at JUNO

JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

Detection of the Diffuse Supernova Neutrino Background with JUNO

As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

Thermal insulating properties of hollow mullite fibers prepared on a ceiba bio-template

Ceiba fibers have excellent thermal insulating properties because of their hollow structures. Mullite fibers are widely used in heat-insulating refractory materials because of their low thermal conductivity and excellent thermal shock stability. However, unlike ceiba fibers, conventional mullite fibers have solid structures, which limits further development of the thermal insulating properties of mullite fibers. Inspired by their hollow structure, we used ceiba fibers as a template for preparing hollow mullite fibers. We immersed ceiba fibers in a precursor solution of Al(NO3)3 and ethyl orthosilicate (TEOS). The impregnated ceiba fibers were then dried and sintered at a high temperature to obtain hollow mullite fibers. The synthesis process, microstructures, phases, pore size distributions, and thermal conductivities of the resulting fibers were analyzed. The results showed that mullite fibers inherited the hollow structure of the ceiba fibers, and the resulting thermal conductivity was markedly reduced compared to solid mullite fibers

Role of miR-128/216a Regulating Isl1 Expression during Differentiation of Human Umbilical Cord Mesenchymal Stem Cells into Insulin-Producing Cells

Islet-1 (Isl1), a LIM homeodomain protein, is expressed in the embryonic pancreatic epithelium. As a key transcription factor, Isl1 can not only regulate insulin gene expression in normal glucose condition but also maintain β-cell function and impact pancreatic β-cell target genes. Some experiments have suggested that MicroRNA (miRNA) can play a critical role during the induction of insulin-producing cells (IPCs). However, it is unclear whether miRNA may regulate Isl1 expression during differentiation of human umbilical cord mesenchymal stem cells (HUMSCs) into IPCs. In this investigation, we induced HUMSCs into IPCs with a modified two-step protocol, activin A, retinoic acid (step1) and conophylline, nicotinamide (step2). To find the miRNA regulating Isl1 expression, we respectively used TargetScan, miRDB and RNAhybrid to predict and got the result, miR-128 and miR-216a. The miRNAs can inhibit Isl1 expression by dual luciferase assay. The results of real-time Polymerase Chain Reaction (PCR) showed that Isl1 expression level was almost reciprocal to that of miR-128 and miR-216a during differentiation of HUMSCs into IPCs. Furthermore, over-expression of miR-128 or miR-216a down-regulated expression levels of Isl1 and MafA. Therefore, miR-128 or miR-216a may regulate expression of islet-specific transcription factors to control differentiation of HUMSCs into IPCs

Solidification texture dependence of the anisotropy of mechanical properties and damping capacities of an AZ31 Mg-based alloy fabricated via wire-arc additive manufacturing

Wire-arc additive manufacturing (WAAM) offers a brand-new method for short process and rapid manufacturing of large magnesium alloy components, which can avoid the formability dilemma faced by Mg alloys due to their poor plasticity. In this study, the relationships between the solidification texture and the anisotropy of mechanical properties/damping capacities of an AZ31 Mg-based alloy fabricated by the WAAM process were studied. The results revealed that the crystallographic texture with the (0001) basal plane along the building direction was promoted by the preferential growth of dendrite arms along the direction of the HCP crystal structure. The (0001) basal texture had a strong influence on the anisotropy of mechanical properties and damping capacities. Compared to the sample with a tensile axis perpendicular to the building direction, the sample with a tensile axis along the building direction displays a simultaneous increase in tensile strength and ductility, which is related to the smaller Schmid factor (SF) for basal slip and better plasticity deformation via non-basal slip and twinning. However, the smaller SF for basal slip also results in a smaller resolved shear stress factor for the breakaway stress during the damping response testing, resulting in lower damping capacities. This work is helpful for further optimizing the mechanical properties and damping capacities of WAAM-processed Mg-based alloys