BmCH25H,a vertebrate interferon-stimulated gene(ISG)homolog,inhibits BmNPV infection dependent on its hydroxylase activity in Bombyx mori

Cholesterol-25-hydroxylase(CH25H)has been identified as an interferon-stimulated gene(ISG)in mammals that exerts its antiviral effects by catalyzing the conversion of cholesterol to 25-hydroxycholesterol(25HC).However,invertebrates lack an antiviral system homologous to vertebrate interferons(IFNs)because the genomes of invertebrates do not encode IFN-like cytokines.Nevertheless,CH25H is present in insect genomes and it therefore deserves further study of whether and by which mechanism it could exert an antiviral effect in invertebrates.In this study,the Bombyx mori CH25H(BmCH25H)gene,of which the encoded protein has high homology with other lepidopteran species,was identified and located on chromosome 9.Interestingly,we found that the expression of BmCH25H was significantly upregulated in B.mori nucleopolyhedrovirus(BmNPV)-infected BmN cells and silkworm(B.mori)larvae at the early infection stage.The inhibitory effect of BmCH25H on BmNPV replication was further demonstrated to depend on its catalytic residues to convert cholesterol to 25HC.More importantly,we demonstrated that during BmNPV infection,BmCH25H expression was increased through the Janus kinase–signal transducer and activator of transcription(JAK–STAT)pathway,similar to the induction of ISGs following virus infection in vertebrates.This is the first report that CH25H has antiviral effects in insects;the study also elucidates the regulation of its expression and its mechanism of action.

The piRNA pathway is required for nucleopolyhedrovirus replication in Lepidoptera

The Piwi-interacting RNA(piRNA)pathway has been shown to be involved in the antiviral defense against RNA viruses,especially in mosquitoes,but its universality has been questioned.Here,we used the Bombyx mori nucleopolyhedrovirus(BmNPV)-infected silkworm as a model to explore the effects of the key factors of piRNA pathway,BmAgo3 and Siwi,on replication of a large DNA virus(belonging to the family of Baculoviridae).We demonstrated that BmAgo3 and Siwi could promote the replication of BmNPV through both overexpression and knockdown experiments in BmN cell lines and silkworm larvae.In addition,we also studied the effect of PIWI-class genes on Autographa californica nucleopolyhedrovirus(AcMNPV)replication in the Spodoptera frugiperda cell line Sf9.By knocking down the expression of PIWI-class genes in Sf9,we found that Piwi-like-1 and Piwi-like-2-3 could inhibit AcMNPV replication,while Piwi-like-4-5 promoted virus replication.Our study provides compelling evidence that the piRNA pathway affects host infection by exogenous viruses in Lepidoptera.Also,our results reflect the diversity of the roles of PIWI-class genes in virus infection of the host across species.This study is the first to explore the interaction of PIWI-class proteins with DNA viruses,providing new insights into the functional roles of the piRNA pathway.

Wide-range color-tunable afterglow emission by the modulation of triplet exciton transition processes based on buckybowl structure

Buckybowl structures as non-uniform electrostatic potential distributions of poly-cyclic aromatic materials show a unique photoelectric performance.In this work,OTC was utilized for dynamic modulation of triplet exciton transition processes.Five host molecules with different functional units were selected,thus providing dif-ferent intermolecular interactions in the host/guest systems.Therefore,the delayed emissions were regulated from 536 to 624 nm via the tuning of the triplet exciton transition processes of OTC in different hosts.Experimental data and theoretical calculations revealed that the varied triplet transition behaviors resulted from the competition between the intersystem crossing(ISC)process of OTC-monomer and the reverse intersystem crossing(RISC)process of OTC-aggregates.This work proves the superior structure of buckybowl-based luminophore for controlling triplet exciton transition processes and supplies a new perspective for persistent afterglow luminophore design.

A first comprehensive evaluation of China's GNSS-R airborne campaign: part II—river remote sensing

The Global Navigation Satellite System Reflectometry(GNSS-R) has been proven to be a powerful technique for retrieving geophysical parameters of ocean and land. Airborne GNSS-R is an important experimental platform, because it is not only needed as validation for spaceborne application, but also possesses the advantages to be capable of remote sensing of small and medium scale targets, such as rivers and lakes. This paper presents an overview of China's airborne GNSS-R campaign conducted on May 30, 2014, in Henan. The campaign has two objectives, i.e.:(1) to examine the capability of a GNSS-R payload developed by National Space Science Center,Chinese Academy of Sciences(NSSC, CAS) for airborneobservations and(2) to study the algorithms for soil moisture and river remote sensing, including altimetry and flow velocity measurement. A previous paper has presented results of soil moisture retrieval as part I, and in this paper,initial results of the Yellow River remote sensing are presented as part II. This paper presents the river altimetry results and explores a new potential application of GNSS-R technology, which is used to detect the flow velocity of the river. The river surface height results observed by code delay altimetry method were consistent with the height results of GPS dual-frequency differential positioning altimetry. The GNSS-R altimetry results showed that decimeter level heights were achieved in 1-min sliding average. Comparing with in situ measurements, the GNSSR flow velocity result was reasonable; the error was about0.027 m/s, which indicated the validity and feasibility of using GNSS-R technique to detect river flow velocity.