Inhibition of SARS-CoV 3C-like Protease Activity by Theaflavin-3,3′-digallate (TF3)

SARS-CoV is the causative agent of severe acute respiratory syndrome (SARS). The virally encoded 3C-like protease (3CL(Pro)) has been presumed critical for the viral replication of SARS-CoV in infected host cells. In this study, we screened a natural product library consisting of 720 compounds for inhibitory activity against 3CL(Pro). Two compounds in the library were found to be inhibitive: tannic acid (IC(50) = 3 µM) and 3-isotheaflavin-3-gallate (TF2B) (IC(50) = 7 µM). These two compounds belong to a group of natural polyphenols found in tea. We further investigated the 3CL(Pro)-inhibitory activity of extracts from several different types of teas, including green tea, oolong tea, Puer tea and black tea. Our results indicated that extracts from Puer and black tea were more potent than that from green or oolong teas in their inhibitory activities against 3CL(Pro). Several other known compositions in teas were also evaluated for their activities in inhibiting 3CL(Pro). We found that caffeine, (—)-epigallocatechin gallte (EGCg), epicatechin (EC), theophylline (TP), catechin (C), epicatechin gallate (ECg) and epigallocatechin (EGC) did not inhibit 3CL(Pro) activity. Only theaflavin-3,3′-digallate (TF3) was found to be a 3CL(Pro) inhibitor. This study has resulted in the identification of new compounds that are effective 3CL(Pro) inhibitors

Crystallographic origin of cycle decay of the high-voltage LiNi\u3csub\u3e0.5\u3c/sub\u3eMn\u3csub\u3e1.5\u3c/sub\u3eO\u3csub\u3e4\u3c/sub\u3e spinel lithium-ion battery electrode

High-voltage spinel LiNi0.5Mn1.5O4 (LNMO) is considered a potential high-power-density positive electrode for lithium-ion batteries, however, it suffers from capacity decay after extended charge-discharge cycling, severely hindering commercial application. Capacity fade is thought to occur through the significant volume change of the LNMO electrode occurring on cycling, and in this work we use operando neutron powder diffraction to compare the structural evolution of the LNMO electrode in an as-assembled 18650-type battery containing a Li4Ti5O12 negative electrode with that in an identical battery following 1000 cycles at high-current. We reveal that the capacity reduction in the battery post cycling is directly proportional to the reduction in the maximum change of the LNMO lattice parameter during its evolution. This is correlated to a corresponding reduction in the MnO6 octahedral distortion in the spinel structure in the cycled battery. Further, we find that the rate of lattice evolution, which reflects the rate of lithium insertion and removal, is ∼9 and ∼10% slower in the cycled than in the as-assembled battery during the Ni2+/Ni3+ and Ni3+/Ni4+ transitions, respectively

Neurexin Superfamily Cell Membrane Receptor Contactin-Associated Protein Like-4 (Cntnap4) Is Involved in Neural EGFL-Like 1 (Nell-1)-Responsive Osteogenesis

Contactin-associated protein-like 4 (Cntnap4) is a member of the neurexin superfamily of transmembrane molecules that have critical functions in neuronal cell communication. Cntnap4 knockout mice display decreased presynaptic gamma-aminobutyric acid (GABA) and increased dopamine release that is associated with severe, highly penetrant, repetitive, and perseverative movements commonly found in human autism spectrum disorder patients. However, no known function of Cntnap4 has been revealed besides the nervous system. Meanwhile, secretory protein neural EGFL-like 1 (Nell-1) is known to exert potent osteogenic effects in multiple small and large animal models without the off-target effects commonly found with bone morphogenetic protein 2. In this study, while searching for a Nell-1-specific cell surface receptor during osteogenesis, we identified and validated a ligand/receptor-like interaction between Nell-1 and Cntnap4 by demonstrating: 1) Nell-1 and Cntnap4 colocalization on the surface of osteogenic-committed cells; 2) high-affinity interaction between Nell-1 and Cntnap4; 3) abrogation of Nell-1-responsive Wnt and MAPK signaling transduction, as well as osteogenic effects, via Cntnap4 knockdown; and 4) replication of calvarial cleidocranial dysplasias-like defects observed in Nell-1-deficient mice in Wnt1-Cre-mediated Cntnap4-knockout transgenic mice. In aggregate, these findings indicate that Cntnap4 plays a critical role in Nell-1-responsive osteogenesis. Further, this is the first functional annotation for Cntnap4 in the musculoskeletal system. Intriguingly, Nell-1 and Cntnap4 also colocalize on the surface of human hippocampal interneurons, implicating Nell-1 as a potential novel ligand for Cntnap4 in the nervous system. This unexpected characterization of the ligand/receptor-like interaction between Nell-1 and Cntnap4 indicates a novel biological functional axis for Nell-1 and Cntnap4 in osteogenesis and, potentially, in neural development and function. © 2018 American Society for Bone and Mineral Research. © 2018 American Society for Bone and Mineral Researc

Proliferation and Osteogenic Differentiation of Mesenchymal Stem Cells Induced by a Short Isoform of NELL-1

Neural epidermal growth factor-like (NEL)-like protein 1 (NELL-1) has been identified as an osteoinductive differentiation factor that promotes mesenchymal stem cell (MSC) osteogenic differentiation. In addition to full-length NELL-1, there are several NELL-1-related transcripts reported. We used rapid amplification of cDNA ends to recover potential cDNA of NELL-1 isoforms. A NELL-1 isoform with the N-terminal 240 amino acid (aa) residues truncated was identified. While full-length NELL-1 that contains 810 aa residues (NELL-1810) plays an important role in embryologic skeletal development, the N-terminal-truncated NELL-1 isoform (NELL-1570) was expressed postnatally. Similar to NELL-1810, NELL-1570 induced MSC osteogenic differentiation. In addition, NELL-1570 significantly stimulated MSC proliferation in multiple MSC-like populations such as murine C3H10T1/2 MSC cell line, mouse primary MSCs, and perivascular stem cells, which is a type of stem cells proposed as the perivascular origin of MSCs. In contrast, NELL-1810 demonstrated only limited stimulation of MSC proliferation. Similar to NELL-1810, NELL-1570 was found to be secreted from host cells. Both NELL-1570 expression lentiviral vector and column-purified recombinant protein NELL-1570 demonstrated almost identical effects in MSC proliferation and osteogenic differentiation, suggesting that NELL-1570 may function as a pro-osteogenic growth factor. In vivo, NELL-1570 induced significant calvarial defect regeneration accompanied by increased cell proliferation. Thus, NELL-1570 has the potential to be used for cell-based or hormone-based therapy of bone regeneration. Stem Cells 2015;33:904-915 © 2014 AlphaMed Press

CDKN2B Upregulation Prevents Teratoma Formation in Multipotent Fibromodulin-Reprogrammed Cells

Tumorigenicity is a well-documented risk to overcome for pluripotent or multipotent cell applications in regenerative medicine. To address the emerging demand for safe cell sources in tissue regeneration, we established a novel, protein-based reprogramming method that does not require genome integration or oncogene activation to yield multipotent fibromodulin (FMOD)-reprogrammed (FReP) cells from dermal fibroblasts. When compared with induced pluripotent stem cells (iPSCs), FReP cells exhibited a superior capability for bone and skeletal muscle regeneration with markedly less tumorigenic risk. Moreover, we showed that the decreased tumorigenicity of FReP cells was directly related to an upregulation of cyclin-dependent kinase inhibitor 2B (CDKN2B) expression during the FMOD reprogramming process. Indeed, sustained suppression of CDKN2B resulted in tumorigenic, pluripotent FReP cells that formed teratomas in vivo that were indistinguishable from iPSC-derived teratomas. These results highlight the pivotal role of CDKN2B in cell fate determination and tumorigenic regulation and reveal an alternative pluripotent/multipotent cell reprogramming strategy that solely uses FMOD protein. © 2019, American Society for Clinical Investigation

Biochar-based fertilizer: Supercharging root membrane potential and biomass yield of rice

Biochar-based compound fertilizers (BCF) and amendments have proven to enhance crop yields and modify soil properties (pH, nutrients, organic matter, structure etc.) and are now in commercial production in China. While there is a good understanding of the changes in soil properties following biochar addition, the interactions within the rhizosphere remain largely unstudied, with benefits to yield observed beyond the changes in soil properties alone. We investigated the rhizosphere interactions following the addition of an activated wheat straw BCF at an application rates of 0.25% (g·g−1 soil), which could potentially explain the increase of plant biomass (by 67%), herbage N (by 40%) and P (by 46%) uptake in the rice plants grown in the BCF-treated soil, compared to the rice plants grown in the soil with conventional fertilizer alone. Examination of the roots revealed that micron and submicron-sized biochar were embedded in the plaque layer. BCF increased soil Eh by 85 mV and increased the potential difference between the rhizosphere soil and the root membrane by 65 mV. This increased potential difference lowered the free energy required for root nutrient accumulation, potentially explaining greater plant nutrient content and biomass. We also demonstrate an increased abundance of plant-growth promoting bacteria and fungi in the rhizosphere. We suggest that the redox properties of the biochar cause major changes in electron status of rhizosphere soils that drive the observed agronomic benefits

A QoS-Guaranteed Coverage Precedence Routing Algorithm for Wireless Sensor Networks

For mission-critical applications of wireless sensor networks (WSNs) involving extensive battlefield surveillance, medical healthcare, etc., it is crucial to have low-power, new protocols, methodologies and structures for transferring data and information in a network with full sensing coverage capability for an extended working period. The upmost mission is to ensure that the network is fully functional providing reliable transmission of the sensed data without the risk of data loss. WSNs have been applied to various types of mission-critical applications. Coverage preservation is one of the most essential functions to guarantee quality of service (QoS) in WSNs. However, a tradeoff exists between sensing coverage and network lifetime due to the limited energy supplies of sensor nodes. In this study, we propose a routing protocol to accommodate both energy-balance and coverage-preservation for sensor nodes in WSNs. The energy consumption for radio transmissions and the residual energy over the network are taken into account when the proposed protocol determines an energy-efficient route for a packet. The simulation results demonstrate that the proposed protocol is able to increase the duration of the on-duty network and provide up to 98.3% and 85.7% of extra service time with 100% sensing coverage ratio comparing with LEACH and the LEACH-Coverage-U protocols, respectively