The genetic diversity among strawberry breeding resources based on SSRs

Cultivated strawberry (Fragaria × ananassa Duch.) is a high value horticultural crop. In this study, the genetic diversity of 160 strawberry accessions was determined using five highly polymorphic simple sequence repeat (SSR) markers. Sixty different alleles were identified, with allele frequencies in the range of 0.006 to1. Similarity scores were in the range of 0.034 to 0.963 (average: 0.507). The accessions were categorized into five groups. Group 1 contained two diploid Fragaria vesca species and one unknown accession. Group 2 contained one accession (F x ananassa). Group 3 contained 20 F × ananassa accessions and six unknown accessions. Group 4 contained 48 F. × ananassa accessions, one octaploid Fragaria chiloensis species, and six unknown accessions while Group 5 contained 69 F. × ananassa accessions and six unknown accessions. Accessions within a pedigree were frequently grouped together. A total of 30 novel accessions were categorized alongside existing accessions. These results will allow breeders to develop strategies which incorporate more genetic diversity into new cultivars

In Situ Self-Cross-Linkable, Long-Term Stable Hyaluronic Acid Filler by Gallol Autoxidation for Tissue Augmentation and Wrinkle Correction

Copyright © 2019 American Chemical Society.Injectable fillers mainly aim to augment tissue volume and correct wrinkles in cosmetic and plastic reconstructions. However, the development of long-lasting, injectable fillers with minimal complications of pain, toxicity, and displacement has been challenging because of the absence of reliable cross-linking chemistry. Here, we report a novel cross-linker-free injectable hydrogel formulated by autoxidation as a highly biocompatible, easily injectable, and long-term volumetrically stable filler agent. Self-cross-linkable hyaluronic acid (SC-HA) with gallol moieties could form a hydrogel via autoxidation of gallols in vivo without additional cross-linking agents. The gelation of SC-HA in situ after injection is accelerated by the self-production of oxygen species and endogenous peroxidase in vivo. The SC-HA filler does not require a high injection force, thus minimizing pain, bleeding, and tissue damage-associated complications. In addition, improved tissue adhesiveness of the SC-HA hydrogel by oxidized gallols (shear strength; 2 kPa) prevented displacement of the filler constructs from the injection site. The SC-HA filler retained its mechanical properties in vivo (600-700 Pa) for wrinkle correction and volumetric augmentation up to 1 year after injection. Overall, the performance of the SC-HA hydrogel as an injectable dermal filler was superior to that of commercially available, chemically cross-linked biphasic HA filler composites in terms of injectability, tissue adhesiveness, and long-term volumetric augmentation. Our injectable HA hydrogel with no need of cross-linkers provides a long-lasting filler that has clinical utility for cosmetic applications11sciescopu

Truncating Mutation in the Autophagy Gene \u3cem\u3eUVRAG\u3c/em\u3e Confers Oncogenic Properties and Chemosensitivity in Colorectal Cancers

Autophagy-related factors are implicated in metabolic adaptation and cancer metastasis. However, the role of autophagy factors in cancer progression and their effect in treatment response remain largely elusive. Recent studies have shown that UVRAG, a key autophagic tumour suppressor, is mutated in common human cancers. Here we demonstrate that the cancer-related UVRAG frameshift (FS), which does not result in a null mutation, is expressed as a truncated UVRAGFS in colorectal cancer (CRC) with microsatellite instability (MSI), and promotes tumorigenesis. UVRAGFS abrogates the normal functions of UVRAG, including autophagy, in a dominant-negative manner. Furthermore, expression of UVRAGFS can trigger CRC metastatic spread through Rac1 activation and epithelial-to-mesenchymal transition, independently of autophagy. Interestingly, UVRAGFS expression renders cells more sensitive to standard chemotherapy regimen due to a DNA repair defect. These results identify UVRAG as a new MSI target gene and provide a mechanism for UVRAG participation in CRC pathogenesis and treatment response

From covalent bonding to coalescence of metallic nanorods

Growth of metallic nanorods by physical vapor deposition is a common practice, and the origin of their dimensions is a characteristic length scale that depends on the three-dimensional Ehrlich-Schwoebel (3D ES) barrier. For most metals, the 3D ES barrier is large so the characteristic length scale is on the order of 200 nm. Using density functional theory-based ab initio calculations, this paper reports that the 3D ES barrier of Al is small, making it infeasible to grow Al nanorods. By analyzing electron density distributions, this paper shows that the small barrier is the result of covalent bonding in Al. Beyond the infeasibility of growing Al nanorods by physical vapor deposition, the results of this paper suggest a new mechanism of controlling the 3D ES barrier and thereby nanorod growth. The modification of local degree of covalent bonding, for example, via the introduction of surfactants, can increase the 3D ES barrier and promote nanorod growth, or decrease the 3D ES barrier and promote thin film growth

Direct Inhibition of GSK3β by the Phosphorylated Cytoplasmic Domain of LRP6 in Wnt/β-Catenin Signaling

Wnt/β-catenin signaling plays a central role in development and is also involved in a diverse array of diseases. Binding of Wnts to the coreceptors Frizzled and LRP6/5 leads to phosphorylation of PPPSPxS motifs in the LRP6/5 intracellular region and the inhibition of GSK3β bound to the scaffold protein Axin. However, it remains unknown how GSK3β is specifically inhibited upon Wnt stimulation. Here, we show that overexpression of the intracellular region of LRP6 containing a Ser/Thr rich cluster and a PPPSPxS motif impairs the activity of GSK3β in cells. Synthetic peptides containing the PPPSPxS motif strongly inhibit GSK3β in vitro only when they are phosphorylated. Microinjection of these peptides into Xenopus embryos confirms that the phosphorylated PPPSPxS motif potentiates Wnt-induced second body axis formation. In addition, we show that the Ser/Thr rich cluster of LRP6 plays an important role in LRP6 binding to GSK3β. These observations demonstrate that phosphorylated LRP6/5 both recruits and directly inhibits GSK3β using two distinct portions of its cytoplasmic sequence, and suggest a novel mechanism of activation in this signaling pathway

Viral Bcl-2-Mediated Evasion of Autophagy Aids Chronic Infection of γHerpesvirus 68

γ-herpesviruses (γHVs) have developed an interaction with their hosts wherein they establish a life-long persistent infection and are associated with the onset of various malignancies. One critical virulence factor involved in the persistency of murine γ-herpesvirus 68 (γHV68) is the viral homolog of the Bcl-2 protein (vBcl-2), which has been implicated to counteract both host apoptotic responses and autophagy pathway. However, the relative significance of the two activities of vBcl-2 in viral persistent infection has yet to be elucidated. Here, by characterizing a series of loss-of-function mutants of vBcl-2, we have distinguished the vBcl-2-mediated antagonism of autophagy from the vBcl-2-mediated inhibition of apoptosis in vitro and in vivo. A mutant γHV68 virus lacking the anti-autophagic activity of vBcl-2 demonstrates an impaired ability to maintain chronic infections in mice, whereas a mutant virus lacking the anti-apoptotic activity of vBcl-2 establishes chronic infections as efficiently as the wild-type virus but displays a compromised ability for ex vivo reactivation. Thus, the vBcl-2-mediated antagonism of host autophagy constitutes a novel mechanism by which γHVs confer persistent infections, further underscoring the importance of autophagy as a critical host determinant in the in vivo latency of γ-herpesviruses

First principles-based atomistic modeling of the structure and nature of amorphous Au-Si alloys and their application to Si nanowire synthesis

textA great deal of attention has been paid to semiconductor nanowires due to their compatibility of conventional silicon-based technology. Metal-catalytic vapor-liquidsolid (VLS) and various solution-based techniques have widely been used to synthesize silicon/germanium (Si/Ge) nanowires. It is well characterized that the crystallographic orientations, diameter sizes, and surface morphologies of semiconductor nanowires can be controlled by varying process conditions and metal catalysts. Earlier experimental and theoretical studies have identified mechanism underlying metal catalyzed Si/Ge nanowire growth, involving Si/Ge diffusion into a metal catalyst, eutectic Si/Ge-catalyst alloy formation, and Si/Ge precipitation at the catalyst-nanowire interface. However, little is known about the atomic-level details of the structure, energetics and dynamics of amorphous metal alloys such as gold-silicon (Au-Si) and gold-germanium (Au-Ge) despite their importance for well controlled synthesis of Si/Ge nanowires, which is essential for the success of Si/Ge nanowires-based applications. Experiments provide many clues to the fundamental aspects of the behavior and properties of metal alloys, but their interpretations often remain controversial due largely to difficulties in direct characterization. While current experimental techniques are still limited to providing complementary atomic-level, real space information, first principles based atomistic modeling has emerged as a powerful means to address the structure, function and properties of amorphous metallic alloys. This thesis work has focused on developing a detailed understanding of the atomic structure, energetics, and oxidation of Au-Si alloys, as well as molecular mechanisms underlying Au-catalyzed Si nanowire growth. In addition, the surface reconstruction and chemistry of Si nanowires has been examined, with comparisons to planar Si surfaces. In this dissertation, based on first principles atomistic simulations, we present: 1) the atomic structure, energetics, and chemical ordering of amorphous Au-Si alloys with varying Au:Si composition ratios; 2) the behavior of boron (B) in the Au-Si alloy, such as diffusion and agglomeration, and the effect of B addition on the atomic distribution of Si and Au, with implications for in-situ doping of Si nanowires; 3) the origin and structural ordering of Si surface segregation in the Au-Si alloy, providing important insights into the nucleation and early-stage growth of Si nanowires; 4) the interfacial interaction between the Au-Si alloy and various facets of crystalline Si, such as (111), (211), (110), (110), which explains well the underlying reasons for the growth direction of Si nanowires; 5) the oxidation of the Au-Si alloy; and 6) the surface reconstruction and chemistry of Si nanowires with comparisons to planar Si surfaces. Outcomes from the thesis work contribute to: clarifying the atomic structure, energetics and chemical ordering of amorphous bulk Au-Si alloys, as well as their surfaces and interfaces; better understanding molecular mechanisms underlying the Aucatalyzed synthesis of Si nanowires; and identifying the surface reconstruction and chemistry of Si nanowires. The improved understanding can provide invaluable guidance on the rational design and fabrication of Si nanowire-based future electronic, chemical, and biological devices. This thesis work also offers a theoretical platform for studying metal alloy systems with various applications.Chemical Engineerin

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Department of Creative Design Engineeringclos