Molecular characterization of an <i>Apple stem grooving virus</i> isolate from kiwifruit (<i>Actinidia chinensis</i>) in China

<p><i>Apple stem grooving virus</i> (ASGV) is the type species of the genus <i>Capillovirus</i> in the family <i>Betaflexiviridae</i>. The virus naturally infects several important horticultural crops. Although many ASGV isolates from apple (<i>Malus</i> spp.), pear (<i>Pyrus</i> spp.), citrus (<i>Citrus</i> spp.) and lily (<i>Lilium</i> spp.) have been characterized, the occurrence status and molecular characteristics of the virus from kiwifruit trees are still largely unknown. In this study, by employing the strategy of small RNA deep sequencing coupled with conventional RT-PCR, we provide the first complete genome sequence of an ASGV isolate (named ASGV-Ac) infecting a kiwifruit plant (<i>Actinidia chinensis</i>) grown in China. The complete genome of ASGV-Ac consisted of 6496 nucleotides, excluding poly (A) tail at its 3ʹ end. ASGV-Ac shared high nucleotide sequence identities of 96.9% and 93.5% with a kiwifruit ASGV isolate reported from New Zealand (accession no. AF522459) for their CP and MP coding regions. However, the isolate was phylogenetically distal to ASGV isolates from all other hosts by sharing 79.5–82.4% genome sequence identity, and likely represented a novel variant. RT-PCR detection revealed the presence of ASGV-infected kiwifruit in two provinces in China. The partial CP gene of nine ASGV isolates determined in this study shared 87.8–99.6% nucleotide sequence identity with the corresponding sequences of other reported ASGV isolates from kiwifruit, indicating molecular diversity of ASGV isolates from kiwifruit plants. This study provides important evidence for monitoring the viral disease and novel molecular information for developing efficient detection techniques to prevent virus spread.</p

δ‑MnO₂–Mn₃O₄ Nanocomposite for Photochemical Water Oxidation: Active Structure Stabilized in the Interface

Pure phase manganese oxides have been widely studied as water oxidation catalysts, but further improvement of their activities is much challenging. Herein, we report an effective method to improve the water oxidation activity by fabricating a nanocomposite of Mn₃O₄ and δ-MnO₂ with an active interface. The nanocomposite was achieved by a partial reduction approach which induced an in situ growth of Mn₃O₄ nanoparticles from the surface of δ-MnO₂ nanosheets. The optimum composition was determined to be 38% Mn₃O₄ and 62% δ-MnO₂ as confirmed by X-ray photoelectron spectra (XPS) and X-ray absorption spectra (XAS). The δ-MnO₂–Mn₃O₄ nanocomposite is a highly active water oxidation catalyst with a turnover frequency (TOF) of 0.93 s^–1, which is much higher than the individual components of δ-MnO₂ and Mn₃O₄. We consider that the enhanced water oxidation activity could be explained by the active interface between two components. At the phase interface, weak Mn–O bonds are introduced by lattice disorder in the transition of hausmannite phase to birnessite phase, which provides active sites for water oxidation catalysis. Our study illustrates a new view to improve water oxidation activity of manganese oxides

Synthesis, Biological Evaluation, and Autophagy Mechanism of 12<i>N</i>‑Substituted Sophoridinamines as Novel Anticancer Agents

A series of 12<i>N</i>-substituted sophoridinamine derivatives were synthesized and evaluated for their cytotoxic activities in human HepG2 hepatoma cells. Structure–activity relationship revealed that introduction of a suitable arylidene or arylethyl at the <i>N</i>′-end could greatly enhance antiproliferation potency. Among them, compound <b>6b</b> possessing a <i>N</i>′-trimethoxyphenyl methylene exhibited potent antiproliferation effect against three human tumor cell lines including HepG2, leukemia (K562), and breast cancer (HMLE), with IC₅₀ between 0.55 and 1.7 μM. The underlying mechanism of <b>6b</b> against tumor cells is to block autophagic flux, mainly through neutralizing lysosomal acidity. Our results indicated that compound <b>6b</b> is a potent lysosomal deacidification agent and is accordingly able to block autophagic flux and inhibit tumor cell growth

Integrating Zeolite-Type Chalcogenide with Titanium Dioxide Nanowires for Enhanced Photoelectrochemical Activity

Developing photoanodes with efficient visible-light harvesting and excellent charge separation still remains a key challenge in photoelectrochemical water splitting. Here zeolite-type chalcogenide CPM-121 is integrated with TiO₂ nanowires to form a heterostructured photoanode, in which crystalline CPM-121 particles serve as a visible light absorber and TiO₂ nanowires serve as an electron conductor. Owing to the small band gap of chalcogenides, the hybrid electrode demonstrates obvious absorption in visible-light range. Electrochemical impedance spectroscopy (EIS) shows that electron transport in the hybrid electrode has been significantly facilitated due to the heterojunction formation. A >3-fold increase in photocurrent is observed on the hybrid electrode under visible-light illumination when it is used as a photoanode in a neutral electrolyte without sacrificial agents. This study opens up a new avenue to explore the potential applications of crystalline porous chalcogenide materials for solar-energy conversion in photoelectrochemistry

Discovery and Development of 8‑Substituted Cycloberberine Derivatives as Novel Antibacterial Agents against MRSA

8-Acetoxycycloberberine (<b>2</b>) with a unique skeleton was first identified to display a potent activity profile against Gram-positive bacteria, especially methicillin-resistant <i>S. aureus</i> (MRSA) with minimum inhibitory concentration (MIC) values of 1–8 μg/mL, suggesting a possible novel mechanism of action against bacteria. Taking <b>2</b> as the lead, 23 new 8-substituted cycloberberine (CBBR) derivatives including ether, amine, and amide were synthesized and evaluated for their antibacterial effect. The structure–activity relationship revealed that the introduction of a suitable substituent at the 8-position could greatly enhance the potency against MRSA. Among them, compounds <b>5d</b> and <b>9e</b> demonstrated equally effective anti-MRSA potency as lead <b>2</b>, with an advantage of having a more stable pharmacokinetics feature. A preliminary mechanism study indicated that compound <b>9e</b> acted upon bacteria partly through catalyzing the cleavage of bacterial DNA. Therefore, we consider that 8-substituted CBBR derivatives constitute a promising class of antibacterial agents in the treatment of MRSA infections