Prevailing PA mutation K356R in avian influenza H9N2 virus increases mammalian replication and pathogenicity

Adaptation of the viral polymerase complex comprising PB1, PB2, and PA is necessary for efficient influenza A virus replication in new host species. We found that PA mutation K356R (PA-K356R) has become predominant since 2014 in avian H9N2 viruses in China as with seasonal human H1N1 viruses. The same mutation is also found in most human isolates of emergent avian H7N9 and H10N8 viruses whose six internal gene segments are derived from the H9N2 virus. We further demonstrated the mammalian adaptive functionality of the PA-K356R mutation. Avian H9N2 virus with the PA-K356R mutation in human A549 cells showed increased nuclear accumulation of PA and increased viral polymerase activity that resulted in elevated levels of viral transcription and virus output. The same mutant virus in mice also enhanced virus replication and caused lethal infection. In addition, combined mutation of PA-K356R and PB2-E627K, a well-known mammalian adaptive marker, in the H9N2 virus showed further cooperative increases in virus production and severity of infection in vitro and in vivo. In summary, PA-K356R behaves as a novel mammalian tropism mutation, which, along with other mutations such as PB2-E627K, might render avian H9N2 viruses adapted for human infection

Morton Lecture Morton Lecture Form and flexibility in phosphoinositide 3-kinases

Abstract PI3Ks (phosphoinositide 3-kinases) have important roles in a variety of cellular activities, including survival, proliferation, growth, shape, migration and intracellular sorting. Consistent with their function in cell survival and growth, the gene for the class Iα PI3K catalytic subunit is a common site of gain-of-function mutations in cancers. Ongoing structural studies of these enzymes and the complexes they make with their regulatory subunits have helped to clarify the mechanistic basis of this role in tumour development. The broad spectrum of biological activities associated with various isotypes of class I PI3Ks has led to an intense search for isotype-specific inhibitors as tools in mammalian cell biology and for therapeutic application. Structural studies of the class I PI3Ks suggest that flexibility may be a component of the catalytic cycle of the enzymes

Highly pathogenic avian influenza H5N6 viruses exhibit enhanced affinity for human type sialic acid receptor and in-contact transmission in model ferrets

Since May 2014, highly pathogenic avian influenza H5N6 virus has been reported to cause six severe human infections three of which were fatal. The biological properties of this subtype, in particular its relative pathogenicity and transmissibility in mammals, are not known. We characterized the virus receptor-binding affinity, pathogenicity, and transmissibility in mice and ferrets of four H5N6 isolates derived from waterfowl in China from 2013-2014. All four H5N6 viruses have acquired a binding affinity for human-like SA alpha 2,6Gal-linked receptor to be able to attach to human tracheal epithelial and alveolar cells. The emergent H5N6 viruses, which share high sequence similarity with the human isolate A/Guangzhou/39715/2014 (H5N6), were fully infective and highly transmissible by direct contact in ferrets but showed less-severe pathogenicity than the parental H5N1 virus. The present results highlight the threat of emergent H5N6 viruses to poultry and human health and the need to closely track their continual adaptation in humans

Neurovirulence of avian influenza virus is dependent on the interaction of viral NP protein with host factor FMRP in the murine brain

Avian influenza viruses (AIVs) are zoonotic viruses that exhibit a range infectivity and severity in the human host. Severe human cases of AIVs infection are often accompanied by neurological symptoms, however, the factors involved in the infection of the central nervous system (CNS) are not well known. In this study, we discovered that avian-like sialic acid (SA)-α2, 3 Gal receptor is highly presented in mammalian (human and mouse) brains. In the generation of a mouse-adapted neurotropic H9N2 AIV (SD16-MA virus) in BALB/c mice, we identified key adaptive mutations in its hemagglutinin (HA) and polymerase basic protein 2 (PB2) genes that conferred viral replication ability in mice brain. The SD16-MA virus showed binding affinity for avian-like SA-α2, 3 Gal receptor, enhanced viral RNP polymerase activity, increased viral protein production and transport that culminated in elevated progeny virus production and severe pathogenicity. We further established that host Fragile X Mental Retardation Protein (FMRP), a highly expressed protein in the brain that physically associated with viral nucleocapsid protein (NP) to facilitate RNP assembly and export, was an essential host factor for the neuronal replication of neurotropic AIVs (H9N2, H5N1 and H10N7 viruses). Our study identified a mechanistic process for AIVs to acquire neurovirulence in mice

Enhanced pathogenicity and neurotropism of mouse-adapted H10N7 influenza virus are mediated by novel PB2 and NA mutations

The H10 subtype of avian influenza viruses (AIVs) circulates globally in wild birds and poultry, and this subtype has been shown to be increasingly prevalent in China. Among the various H10 viruses, H10N7 AIVs have caused repeated mammal and human infections. To investigate their genetic adaptation in mammals, we generated a mouse-adapted avian H10N7 variant (A/mallard/Beijing/27/2011-MA; BJ27-MA) which exhibited increased virulence in mice compared to wild-type virus and acquired neurotropism. Sequencing showed the absence of the widely recognized mammalian adaptation markers of E627K and D701N in PB2 in the mouse-adapted strain; instead, five amino acid mutations were identified: E158G and M631L in PB2; G218E in haemagglutinin (H3 numbering); and K110E and S453I in neuraminidase (NA). The neurovirulence of the BJ27-MA virus necessitated the combined presence of the PB2 and NA mutations. Mutations M631L and E158G of PB2 and K110E of NA were required to mediate increased virus replication and severity of infection in mice and mammalian cells. PB2-M631L was functionally the most dominant mutation in that it strongly upregulated viral polymerase activity and played a critical role in the enhancement of virus replication and disease severity in mice. K110E mutation in NA, on the other hand, significantly promoted NA enzymatic activity. These results indicate that the novel mutations in PB2 and NA genes are critical for the adaptation of H10N7 AIV in mice, and they could serve as molecular signatures of virus transmission to mammalian hosts, including humans

Pigeonpea

Pigeonpea is one of the major grain legumes grown in the tropics and subtropics of the world that forms a significant component of the diet due to its high protein content. Most of the differences in potential and realized yields in pigeonpea have been attributed to several biotic and abiotic constraints; besides the low productivity potential of marginal lands, where this crop is commonly grown. Of the various constraints limiting pigeonpea production, insect pests cause substantial damages. Conventional breeding efforts in pigeonpea crop improvement have been successful in producing improved seed quality and reduction of crop maturity duration. Nevertheless, genetic improvement of pigeonpea has been restricted due to the nonavailability of better genetic resources and strong sexual barriers between the cultivated and wild species. The recent developments in plant genetic engineering have provided immense potential in overcoming some of these constraints, thereby, offering opportunities for its successful integration with conventional crop improvement strategies. This chapter describes the pigeonpea crop, various constraints to its productivity, recent developments in its breeding, and emerging transgenic innovations that could play a significant role in the improvement of pigeonpea crop. We also highlight the current status of pigeonpea transgenics and related biosafety and IPR issues for the successful application of this technology in the near future

Software Evolvability Measurement Framework during an Open Source Software Evolution

Context： Software evolution comes with the increasing growth of software applications both in size and complexity. Unlike the software maintenance, software evolution addresses more on the adaption of the new fast-changing requirements. Then the term of “software evolvability” comes with its importance for evaluating the evolution status of the software. However, it is not clearly identified especially in the context of open source software (OSS). Besides the most studies are about the description of software evolvability as a quality attribute, and very few research have done on the measurement of software evolvability during the software evolution process. Objectives： In this study we perform an in-depth investigation on identification of the OSS evolvability, and figure out the appropriate metrics used for measuring the OSS evolvability. Based on that we finally proposed the open source software evolvability measurement framework (OSEM) which could be used for measuring the software evolvability generally in an OSS context. Methods： At first, we conducted a literature review by combining backward snowballing search with systematic database search. Two research questions which are RQ1 and RQ2 are proposed for helping us to retrieve the key information for building the needed framework. Then we performed a case study on VLC media player (an OSS project) to validate the processes of the proposed framework. Results： Based on literature we could explicitly identify the OSS evolvability, and figure out the differences of software evolvability addressed in OSS context and non OSS context (e.g, the traceability refers to documentation in non OSS context, however in OSS context it refers to the release version of OSS project). Besides we also fulfill the evolvability measuring method by addressing the process of prioritization of evolvability sub-characteristics. In the end we implement the OSEM framework on VLC media player and get the well documented results which are clearly presented and easy to understand. Such results could be taken by the VLC developers as an input for the design and development of the VLC. Conclusions: We conclude that the open source software measurement framework (OSEM) is applicable, based on the time we spent on the case of VLC media player it is quite fast and efficient to use such framework. The results from the conduction of this framework are documented well and very clear for OSS users/developers to follow

Experimental Study of a New Pneumatic Actuating System Using Exhaust Recycling

Pneumatic actuating systems are an important power system in industrial applications. Due to exhaust loss, however, pneumatic actuating systems have suffered from a low utilization of compressed air. To recycle the exhaust energy, a novel pneumatic circuit was proposed to realize energy savings through recycling exhaust energy. The circuit consisted of three two-position three-way switch valves, which were used to control the exhaust flows into a gas tank or the ambient environment. This paper introduced the energy recovery configuration and working principles and built a mathematical model of its working process. Then, the mathematical model was verified by experiments. Finally, through experiments in which the air supply pressure, the critical pressure and the volume of the gas tank were regulated, the energy recovery characteristics of the pneumatic actuating system were obtained. Using the new circuit, the experimental results showed that the energy recovery efficiency exceeded 23%. When the air supply pressure was set to 5 bar, 6 bar, and 7 bar, the time required for pneumatic actuation to complete the three working cycles were 5.2 s, 5.3 s, and 5.9 s, respectively. When the critical pressure was set to 0 bar, 0.5 bar, 1 bar, and 1.5 bar, the times for pneumatic actuation to complete the three working cycles were 4.9 s, 5.1 s, 5.2 s, and 5.3 s, respectively. When the volume of the gas tank was set to 2 L, 3 L, 4 L, and 5 L, the number of working cycles was 3, 4, 5, and 6, respectively. This paper provides a new method of cylinder exhaust recycling and lays a good foundation for pneumatic energy savings

Characterization of the Volatile Compounds in Camellia oleifera Seed Oil from Different Geographic Origins

Volatile flavor of edible oils is an important quality index and factor affecting consumer choice. The purpose of this investigation was to characterize virgin Camellia oleifera seed oil (VCO) samples from different locations in southern China in terms of their volatile compounds to show the classification of VCO with respect to geography. Different samples from 20 producing VCO regions were collected in 2020 growing season, at almost the same maturity stage, and processed under the same conditions. Headspace solid-phase microextraction (HS-SPME) with a gas chromatography–mass spectrometer system (GC–MS) was used to analyze volatile compounds. A total of 348 volatiles were characterized, including aldehydes, ketones, alcohols, acids, esters, alkenes, alkanes, furans, phenols, and benzene; the relative contents ranged from 7.80–58.68%, 1.73–12.52%, 2.91–37.07%, 2.73–46.50%, 0.99–12.01%, 0.40–14.95%, 0.00–27.23%, 0.00–3.75%, 0.00–7.34%, and 0.00–1.55%, respectively. The VCO geographical origins with the largest number of volatile compounds was Xixiangtang of Guangxi (L17), and the least was Beireng of Hainan (L19). A total of 23 common and 98 unique volatile compounds were detected that reflected the basic and characteristic flavor of VCO, respectively. After PCA, heatmap and PLS-DA analysis, Longchuan of Guangdong (L8), Qingshanhu of Jiangxi (L16), and Panlong of Yunnan (L20) were in one group where the annual average temperatures are relatively low, where annual rainfalls are also low. Guangning of Guangdong (L6), Yunan of Guangdong (L7), Xingning of Guangdong (L9), Tianhe of Guangdong (L10), Xuwen of Guangdong (L11), and Xiuying of Hainan (L18) were in another group where the annual average temperatures are relatively high, and the altitudes are low. Hence, volatile compound distributions confirmed the differences among the VCO samples from these geographical areas, and the provenance difference evaluation can be carried out by flavor

miRNA expression profiling and zeatin dynamic changes in a new model system of in vivo indirect regeneration of tomato.

Callus formation and adventitious shoot differentiation could be observed on the cut surface of completely decapitated tomato plants. We propose that this process can be used as a model system to investigate the mechanisms that regulate indirect regeneration of higher plants without the addition of exogenous hormones. This study analyzed the patterns of trans-zeatin and miRNA expression during in vivo regeneration of tomato. Analysis of trans-zeatin revealed that the hormone cytokinin played an important role in in vivo regeneration of tomato. Among 183 miRNAs and 1168 predicted target genes sequences identified, 93 miRNAs and 505 potential targets were selected based on differential expression levels for further characterization. Expression patterns of six miRNAs, including sly-miR166, sly-miR167, sly-miR396, sly-miR397, novel 156, and novel 128, were further validated by qRT-PCR. We speculate that sly-miR156, sly-miR160, sly-miR166, and sly-miR397 play major roles in callus formation of tomato during in vivo regeneration by regulating cytokinin, IAA, and laccase levels. Overall, our microRNA sequence and target analyses of callus formation during in vivo regeneration of tomato provide novel insights into the regulation of regeneration in higher plants