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1.
Nature ; 619(7969): 338-347, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37380775

RESUMO

Spillover events of avian influenza A viruses (IAVs) to humans could represent the first step in a future pandemic1. Several factors that limit the transmission and replication of avian IAVs in mammals have been identified. There are several gaps in our understanding to predict which virus lineages are more likely to cross the species barrier and cause disease in humans1. Here, we identified human BTN3A3 (butyrophilin subfamily 3 member A3)2 as a potent inhibitor of avian IAVs but not human IAVs. We determined that BTN3A3 is expressed in human airways and its antiviral activity evolved in primates. We show that BTN3A3 restriction acts primarily at the early stages of the virus life cycle by inhibiting avian IAV RNA replication. We identified residue 313 in the viral nucleoprotein (NP) as the genetic determinant of BTN3A3 sensitivity (313F or, rarely, 313L in avian viruses) or evasion (313Y or 313V in human viruses). However, avian IAV serotypes, such as H7 and H9, that spilled over into humans also evade BTN3A3 restriction. In these cases, BTN3A3 evasion is due to substitutions (N, H or Q) in NP residue 52 that is adjacent to residue 313 in the NP structure3. Thus, sensitivity or resistance to BTN3A3 is another factor to consider in the risk assessment of the zoonotic potential of avian influenza viruses.


Assuntos
Aves , Interações entre Hospedeiro e Microrganismos , Vírus da Influenza A , Influenza Aviária , Influenza Humana , Zoonoses Virais , Animais , Humanos , Aves/virologia , Vírus da Influenza A/classificação , Vírus da Influenza A/genética , Vírus da Influenza A/crescimento & desenvolvimento , Vírus da Influenza A/isolamento & purificação , Influenza Aviária/transmissão , Influenza Aviária/virologia , Influenza Humana/prevenção & controle , Influenza Humana/transmissão , Influenza Humana/virologia , Primatas , Sistema Respiratório/metabolismo , Sistema Respiratório/virologia , Medição de Risco , Zoonoses Virais/prevenção & controle , Zoonoses Virais/transmissão , Zoonoses Virais/virologia , Replicação Viral
2.
PLoS Biol ; 19(9): e3001352, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34491982

RESUMO

Antiviral defenses can sense viral RNAs and mediate their destruction. This presents a challenge for host cells since they must destroy viral RNAs while sparing the host mRNAs that encode antiviral effectors. Here, we show that highly upregulated interferon-stimulated genes (ISGs), which encode antiviral proteins, have distinctive nucleotide compositions. We propose that self-targeting by antiviral effectors has selected for ISG transcripts that occupy a less self-targeted sequence space. Following interferon (IFN) stimulation, the CpG-targeting antiviral effector zinc-finger antiviral protein (ZAP) reduces the mRNA abundance of multiple host transcripts, providing a mechanistic explanation for the repression of many (but not all) interferon-repressed genes (IRGs). Notably, IRGs tend to be relatively CpG rich. In contrast, highly upregulated ISGs tend to be strongly CpG suppressed. Thus, ZAP is an example of an effector that has not only selected compositional biases in viral genomes but also appears to have notably shaped the composition of host transcripts in the vertebrate interferome.


Assuntos
Fosfatos de Dinucleosídeos , Fatores Reguladores de Interferon/genética , RNA Viral , Proteínas de Ligação a RNA/metabolismo , Células A549 , Linhagem Celular , Humanos , Interferon beta/farmacologia , RNA Mensageiro , Proteínas de Ligação a RNA/genética , Fenômenos Fisiológicos Virais , Vírus
3.
PLoS Biol ; 19(2): e3001091, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33630831

RESUMO

The recent emergence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the underlying cause of Coronavirus Disease 2019 (COVID-19), has led to a worldwide pandemic causing substantial morbidity, mortality, and economic devastation. In response, many laboratories have redirected attention to SARS-CoV-2, meaning there is an urgent need for tools that can be used in laboratories unaccustomed to working with coronaviruses. Here we report a range of tools for SARS-CoV-2 research. First, we describe a facile single plasmid SARS-CoV-2 reverse genetics system that is simple to genetically manipulate and can be used to rescue infectious virus through transient transfection (without in vitro transcription or additional expression plasmids). The rescue system is accompanied by our panel of SARS-CoV-2 antibodies (against nearly every viral protein), SARS-CoV-2 clinical isolates, and SARS-CoV-2 permissive cell lines, which are all openly available to the scientific community. Using these tools, we demonstrate here that the controversial ORF10 protein is expressed in infected cells. Furthermore, we show that the promising repurposed antiviral activity of apilimod is dependent on TMPRSS2 expression. Altogether, our SARS-CoV-2 toolkit, which can be directly accessed via our website at https://mrcppu-covid.bio/, constitutes a resource with considerable potential to advance COVID-19 vaccine design, drug testing, and discovery science.


Assuntos
Vacinas contra COVID-19 , COVID-19/diagnóstico , COVID-19/virologia , Genética Reversa , SARS-CoV-2/genética , Células A549 , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , Chlorocebus aethiops , Códon , Humanos , Hidrazonas/farmacologia , Camundongos , Morfolinas/farmacologia , Fases de Leitura Aberta , Plasmídeos/genética , Pirimidinas/farmacologia , Serina Endopeptidases/metabolismo , Células Vero , Proteínas Virais/metabolismo
4.
Chem Rev ; 122(13): 11830-11895, 2022 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-35442645

RESUMO

This Review provides an overview of the emerging concepts of catalysts, membranes, and membrane electrode assemblies (MEAs) for water electrolyzers with anion-exchange membranes (AEMs), also known as zero-gap alkaline water electrolyzers. Much of the recent progress is due to improvements in materials chemistry, MEA designs, and optimized operation conditions. Research on anion-exchange polymers (AEPs) has focused on the cationic head/backbone/side-chain structures and key properties such as ionic conductivity and alkaline stability. Several approaches, such as cross-linking, microphase, and organic/inorganic composites, have been proposed to improve the anion-exchange performance and the chemical and mechanical stability of AEMs. Numerous AEMs now exceed values of 0.1 S/cm (at 60-80 °C), although the stability specifically at temperatures exceeding 60 °C needs further enhancement. The oxygen evolution reaction (OER) is still a limiting factor. An analysis of thin-layer OER data suggests that NiFe-type catalysts have the highest activity. There is debate on the active-site mechanism of the NiFe catalysts, and their long-term stability needs to be understood. Addition of Co to NiFe increases the conductivity of these catalysts. The same analysis for the hydrogen evolution reaction (HER) shows carbon-supported Pt to be dominating, although PtNi alloys and clusters of Ni(OH)2 on Pt show competitive activities. Recent advances in forming and embedding well-dispersed Ru nanoparticles on functionalized high-surface-area carbon supports show promising HER activities. However, the stability of these catalysts under actual AEMWE operating conditions needs to be proven. The field is advancing rapidly but could benefit through the adaptation of new in situ techniques, standardized evaluation protocols for AEMWE conditions, and innovative catalyst-structure designs. Nevertheless, single AEM water electrolyzer cells have been operated for several thousand hours at temperatures and current densities as high as 60 °C and 1 A/cm2, respectively.

5.
PLoS Pathog ; 17(9): e1009929, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34534263

RESUMO

Remdesivir (RDV), a broadly acting nucleoside analogue, is the only FDA approved small molecule antiviral for the treatment of COVID-19 patients. To date, there are no reports identifying SARS-CoV-2 RDV resistance in patients, animal models or in vitro. Here, we selected drug-resistant viral populations by serially passaging SARS-CoV-2 in vitro in the presence of RDV. Using high throughput sequencing, we identified a single mutation in RNA-dependent RNA polymerase (NSP12) at a residue conserved among all coronaviruses in two independently evolved populations displaying decreased RDV sensitivity. Introduction of the NSP12 E802D mutation into our SARS-CoV-2 reverse genetics backbone confirmed its role in decreasing RDV sensitivity in vitro. Substitution of E802 did not affect viral replication or activity of an alternate nucleoside analogue (EIDD2801) but did affect virus fitness in a competition assay. Analysis of the globally circulating SARS-CoV-2 variants (>800,000 sequences) showed no evidence of widespread transmission of RDV-resistant mutants. Surprisingly, we observed an excess of substitutions in spike at corresponding sites identified in the emerging SARS-CoV-2 variants of concern (i.e., H69, E484, N501, H655) indicating that they can arise in vitro in the absence of immune selection. The identification and characterisation of a drug resistant signature within the SARS-CoV-2 genome has implications for clinical management and virus surveillance.


Assuntos
Monofosfato de Adenosina/análogos & derivados , Alanina/análogos & derivados , Antivirais/farmacologia , Tratamento Farmacológico da COVID-19 , RNA-Polimerase RNA-Dependente de Coronavírus/genética , Resistência Microbiana a Medicamentos/genética , SARS-CoV-2/efeitos dos fármacos , Monofosfato de Adenosina/farmacologia , Alanina/farmacologia , Animais , Evolução Biológica , Chlorocebus aethiops , Humanos , Mutação , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus/metabolismo , Células Vero
6.
J Perianesth Nurs ; 38(6): 845-850, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37589630

RESUMO

PURPOSE: The use of lung protective ventilation (LPV) during general anesthesia is an effective strategy among certified registered nurse anesthetists (CRNAs) to reduce and prevent the incidence of postoperative pulmonary complications. The purpose of this project was to implement a LPV protocol, assess CRNA provider adherence, and investigate differences in ventilation parameters and postoperative oxygen requirements. DESIGN: This quality improvement project was conducted using a pre- and postimplementation design. METHODS: Sixty patients undergoing robotic laparoscopic abdominal surgery and 35 CRNAs at a community hospital participated. An evidence-based intraoperative LPV protocol was developed, CRNA education was provided, and the protocol was implemented. Pre- and postimplementation, CRNA knowledge, and confidence were assessed. Ventilation data were collected at 1-minute intervals intraoperatively and oxygen requirements were recorded in the postanesthesia care unit (PACU). FINDINGS: Use of intraoperative LPV strategies increased 2.4%. Overall CRNA knowledge (P = .588), confidence (P = .031), and practice (P < .001) improved from pre- to postimplementation. Driving pressures decreased from pre- to postimplementation (P < .001). Supplemental oxygen use on admission to the PACU decreased from 93.3% to 70.0%. CONCLUSIONS: Educational interventions and implementation of a standardized protocol can improve the use of intraoperative LPV strategies and patient outcomes.


Assuntos
Enfermeiros Anestesistas , Respiração Artificial , Humanos , RNA Complementar , Pulmão , Complicações Pós-Operatórias/prevenção & controle , Oxigênio
7.
Mol Ecol ; 31(3): 822-838, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34779078

RESUMO

Masting, the synchronous, highly variable flowering across years by a population of perennial plants, has been reported to be precipitated by various factors including nitrogen levels, drought conditions, and spring and summer temperatures. However, the molecular mechanism leading to the initiation of flowering in masting plants in particular years remains largely unknown, despite the potential impact of climate change on masting phenology. We studied genes controlling flowering in the alpine snow tussock Chionochloa pallens (Poaceae), a strongly masting perennial grass. We used a range of in situ and manipulated plants to obtain leaf samples from tillers (shoots) which subsequently remained vegetative or flowered. Here, we show that a novel orthologue of TERMINAL FLOWER 1 (TFL1; normally a repressor of flowering in other species) promotes the induction of flowering in C. pallens (hence Anti-TFL1), a conclusion supported by structural, functional and expression analyses. Global transcriptomic analysis indicated differential expression of CpTPS1, CpGA20ox1, CpREF6 and CpHDA6, emphasizing the role of endogenous cues and epigenetic regulation in terms of responsiveness of plants to initiate flowering. Our molecular-based study provides insights into the cellular mechanism of flowering in masting plants and will supplement ecological and statistical models to predict how masting will respond to global climate change.


Assuntos
Poaceae , Neve , Mudança Climática , Epigênese Genética , Flores/genética , Regulação da Expressão Gênica de Plantas , Poaceae/genética
8.
J Intellect Disabil ; 26(4): 869-884, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34823397

RESUMO

BACKGROUND: COVID-19 influenced education delivery worldwide. The Up the Hill Project (UTHP), a university mentoring program in Australia for people with intellectual disability, transitioned from a face-to-face to online format during 2020. RESULTS: The experience of transitioning online for one semester (12-week period) had positives and challenges associated with it. The UTHP Coordinator reported initial doubts for the online mode and identified the importance of at home support. However, the experience has opened up avenues for future program practices, such as intake processes and increased flexibility. From the participants' perspective, the online experience supported participants to develop new technology skills. However, challenges were that participants needed support, and missed face-to-face contact. CONCLUSION: Online mentoring in the UTHP had challenges, but has also supported continuation of university programs. Lessons learnt will influence the development of the UTHP in some capacity into the future.


Assuntos
COVID-19 , Deficiência Intelectual , Tutoria , Adulto , Humanos , Universidades , Mentores
9.
New Phytol ; 229(3): 1312-1325, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32931621

RESUMO

Short-term temperature response curves of leaf dark respiration (R-T) provide insights into a critical process that influences plant net carbon exchange. This includes how respiratory traits acclimate to sustained changes in the environment. Our study analysed 860 high-resolution R-T (10-70°C range) curves for: (a) 62 evergreen species measured in two contrasting seasons across several field sites/biomes; and (b) 21 species (subset of those sampled in the field) grown in glasshouses at 20°C : 15°C, 25°C : 20°C and 30°C : 25°C, day : night. In the field, across all sites/seasons, variations in R25 (measured at 25°C) and the leaf T where R reached its maximum (Tmax ) were explained by growth T (mean air-T of 30-d before measurement), solar irradiance and vapour pressure deficit, with growth T having the strongest influence. R25 decreased and Tmax increased with rising growth T across all sites and seasons with the single exception of winter at the cool-temperate rainforest site where irradiance was low. The glasshouse study confirmed that R25 and Tmax thermally acclimated. Collectively, the results suggest: (1) thermal acclimation of leaf R is common in most biomes; and (2) the high T threshold of respiration dynamically adjusts upward when plants are challenged with warmer and hotter climates.


Assuntos
Aclimatação , Folhas de Planta , Ecossistema , Respiração , Temperatura
10.
Mol Ecol ; 30(8): 1846-1863, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33624370

RESUMO

Mast flowering (or masting) is synchronous, highly variable flowering among years in populations of perennial plants. Despite having widespread consequences for seed consumers, endangered fauna and human health, masting is hard to predict. While observational studies show links to various weather patterns in different plant species, the mechanism(s) underpinning the regulation of masting is still not fully explained. We studied floral induction in Celmisia lyallii (Asteraceae), a mast flowering herbaceous alpine perennial, comparing gene expression in flowering and nonflowering plants. We performed translocation experiments to induce the floral transition in C. lyallii plants followed by both global and targeted expression analysis of flowering-pathway genes. Differential expression analysis showed elevated expression of ClSOC1 and ClmiR172 (promoters of flowering) in leaves of plants that subsequently flowered, in contrast to elevated expression of ClAFT and ClTOE1 (repressors of flowering) in leaves of plants that did not flower. The warm summer conditions that promoted flowering led to differential regulation of age and hormonal pathway genes, including ClmiR172 and ClGA20ox2, known to repress the expression of floral repressors and permit flowering. Upregulated expression of epigenetic modifiers of floral promoters also suggests that plants may maintain a novel "summer memory" across years to induce flowering. These results provide a basic mechanistic understanding of floral induction in masting plants and evidence of their ability to imprint various environmental cues to synchronize flowering, allowing us to better predict masting events under climate change.


Assuntos
Asteraceae , Asteraceae/genética , Mudança Climática , Flores/genética , Regulação da Expressão Gênica de Plantas , Humanos , Folhas de Planta , Sementes
11.
J Virol ; 93(2)2019 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-30381488

RESUMO

The PA-X protein of influenza A virus has roles in host cell shutoff and viral pathogenesis. While most strains are predicted to encode PA-X, strain-dependent variations in activity have been noted. We found that PA-X protein from the A/PR/8/34 (PR8) strain had significantly lower repressive activity against cellular gene expression than PA-X proteins from the avian strains A/turkey/England/50-92/91 (H5N1) (T/E) and A/chicken/Rostock/34 (H7N1). Loss of normal PA-X expression, either by mutation of the frameshift site or by truncating the X open reading frame (ORF), had little effect on the infectious virus titer of PR8 or PR8 7:1 reassortants with T/E segment 3 grown in embryonated hens' eggs. However, in both virus backgrounds, mutation of PA-X led to decreased embryo mortality and lower overall pathology, effects that were more pronounced in the PR8 strain than in the T/E reassortant, despite the low shutoff activity of the PR8 PA-X. Purified PA-X mutant virus particles displayed an increased ratio of hemagglutinin (HA) to nucleoprotein (NP) and M1 compared to values for their wild-type (WT) counterparts, suggesting altered virion composition. When the PA-X gene was mutated in the background of poorly growing PR8 6:2 vaccine reassortant analogues containing the HA and neuraminidase (NA) segments from H1N1 2009 pandemic viruses or from an avian H7N3 strain, HA yield increased up to 2-fold. This suggests that the PR8 PA-X protein may harbor a function unrelated to host cell shutoff and that disruption of the PA-X gene has the potential to improve the HA yield of vaccine viruses.IMPORTANCE Influenza A virus is a widespread pathogen that affects both humans and a variety of animal species, causing regular epidemics and sporadic pandemics, with major public health and economic consequences. A better understanding of virus biology is therefore important. The primary control measure is vaccination, which for humans mostly relies on antigens produced in eggs from PR8-based viruses bearing the glycoprotein genes of interest. However, not all reassortants replicate well enough to supply sufficient virus antigen for demand. The significance of our research lies in identifying that mutation of the PA-X gene in the PR8 strain of virus can improve antigen yield, potentially by decreasing the pathogenicity of the virus in embryonated eggs.


Assuntos
Vírus da Influenza A/patogenicidade , Mutação , Vírus Reordenados/patogenicidade , Proteínas Repressoras/genética , Proteínas não Estruturais Virais/genética , Animais , Embrião de Galinha , Galinhas , Cães , Células HEK293 , Humanos , Virus da Influenza A Subtipo H5N1/genética , Virus da Influenza A Subtipo H5N1/patogenicidade , Vírus da Influenza A Subtipo H7N1/genética , Vírus da Influenza A Subtipo H7N1/patogenicidade , Vírus da Influenza A/genética , Influenza Aviária/virologia , Células Madin Darby de Rim Canino , Vírus Reordenados/genética
12.
J Virol ; 93(20)2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31375575

RESUMO

Vesicular stomatitis Indiana virus (VSIV), formerly known as vesicular stomatitis virus (VSV) Indiana (VSVIND), is a model virus that is exceptionally sensitive to the inhibitory action of interferons (IFNs). Interferons induce an antiviral state by stimulating the expression of hundreds of interferon-stimulated genes (ISGs). These ISGs can constrain viral replication, limit tissue tropism, reduce pathogenicity, and inhibit viral transmission. Since VSIV is used as a backbone for multiple oncolytic and vaccine strategies, understanding how ISGs restrict VSIV not only helps in understanding VSIV-induced pathogenesis but also helps us evaluate and understand the safety and efficacy of VSIV-based therapies. Thus, there is a need to identify and characterize the ISGs that possess anti-VSIV activity. Using arrayed ISG expression screening, we identified TRIM69 as an ISG that potently inhibits VSIV. This inhibition was highly specific as multiple viruses, including influenza A virus, HIV-1, Rift Valley fever virus, and dengue virus, were unaffected by TRIM69. Indeed, just one amino acid substitution in VSIV can govern sensitivity/resistance to TRIM69. Furthermore, TRIM69 is highly divergent in human populations and exhibits signatures of positive selection that are consistent with this gene playing a key role in antiviral immunity. We propose that TRIM69 is an IFN-induced inhibitor of VSIV and speculate that TRIM69 could be important in limiting VSIV pathogenesis and might influence the specificity and/or efficacy of vesiculovirus-based therapies.IMPORTANCE Vesicular stomatitis Indiana virus (VSIV) is a veterinary pathogen that is also used as a backbone for many oncolytic and vaccine strategies. In natural and therapeutic settings, viral infections like VSIV are sensed by the host, and as a result the host cells make proteins that can protect them from viruses. In the case of VSIV, these antiviral proteins constrain viral replication and protect most healthy tissues from virus infection. In order to understand how VSIV causes disease and how healthy tissues are protected from VSIV-based therapies, it is crucial that we identify the proteins that inhibit VSIV. Here, we show that TRIM69 is an antiviral defense that can potently and specifically block VSIV infection.


Assuntos
Interações Hospedeiro-Patógeno , Proteínas com Motivo Tripartido/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Estomatite Vesicular/metabolismo , Estomatite Vesicular/virologia , Vírus da Estomatite Vesicular Indiana/fisiologia , Replicação Viral , Alelos , Sequência de Aminoácidos , Animais , Antivirais/farmacologia , Vírus da Dengue/fisiologia , Resistência à Doença , Interações Hospedeiro-Patógeno/genética , Interações Hospedeiro-Patógeno/imunologia , Humanos , Interferons/metabolismo , Interferons/farmacologia , Família Multigênica , Fosforilação , Transdução de Sinais , Proteínas com Motivo Tripartido/química , Proteínas com Motivo Tripartido/genética , Ubiquitina-Proteína Ligases/química , Ubiquitina-Proteína Ligases/genética , Estomatite Vesicular/genética , Estomatite Vesicular/imunologia
13.
Ann Bot ; 125(6): 851-858, 2020 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-31960889

RESUMO

BACKGROUND: Mast flowering ('masting') is characterized by mass synchronized flowering at irregular intervals in populations of perennial plants over a wide geographical area, resulting in irregular high seed production. While masting is a global phenomenon, it is particularly prevalent in the alpine flora of New Zealand. Increases in global temperature may alter the masting pattern, affecting wider communities with a potential impact on plant-pollinator interactions, seed set and food availability for seed-consuming species. SCOPE: This review summarizes an ecological temperature model (ΔT) that is being used to predict the intensity of a masting season. We introduce current molecular studies on flowering and the concept of an 'epigenetic summer memory' as a driver of mast flowering. We propose a hypothetical model based on temperature-associated epigenetic modifications of the floral integrator genes FLOWERING LOCUS T, FLOWERING LOCUS C and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1. CONCLUSIONS: Genome-wide transcriptomic and targeted gene expression analyses are needed to establish the developmental and physiological processes associated with masting. Such analyses may identify changes in gene expression that can be used to predict the intensity of a forthcoming masting season, as well as to determine the extent to which climate change will influence the mass synchronized flowering of masting species, with downstream impacts on their associated communities.


Assuntos
Mudança Climática , Sementes , Epigênese Genética , Flores , Nova Zelândia , Estações do Ano
14.
J Gen Virol ; 100(7): 1079-1092, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31169484

RESUMO

Candidate vaccine viruses (CVVs) for seasonal influenza A virus are made by reassortment of the antigenic virus with an egg-adapted strain, typically A/Puerto Rico/8/34 (PR8). Many 2009 A(H1N1) pandemic (pdm09) high-growth reassortants (HGRs) selected this way contain pdm09 segment 2 in addition to the antigenic genes. To investigate this, we made CVV mimics by reverse genetics (RG) that were either 6 : 2 or 5 : 3 reassortants between PR8 and two pdm09 strains, A/California/7/2009 (Cal7) and A/England/195/2009, differing in the source of segment 2. The 5 : 3 viruses replicated better in MDCK-SIAT1 cells than the 6 : 2 viruses, but the 6 : 2 CVVs gave higher haemagglutinin (HA) antigen yields from eggs. This unexpected phenomenon reflected temperature sensitivity conferred by pdm09 segment 2, as the egg HA yields of the 5 : 3 viruses improved substantially when viruses were grown at 35 °C compared with 37.5 °C, whereas the 6 : 2 virus yields did not. However, the authentic 5 : 3 pdm09 HGRs, X-179A and X-181, were not markedly temperature sensitive despite their PB1 sequences being identical to that of Cal7, suggesting compensatory mutations elsewhere in the genome. Sequence comparisons of the PR8-derived backbone genes identified polymorphisms in PB2, NP, NS1 and NS2. Of these, PB2 N701D affected the temperature dependence of viral transcription and, furthermore, improved and drastically reduced the temperature sensitivity of the HA yield from the 5 : 3 CVV mimic. We conclude that the HA yield of pdm09 CVVs can be affected by an epistatic interaction between PR8 PB2 and pdm09 PB1, but that this can be minimized by ensuring that the backbones used for vaccine manufacture in eggs contain PB2 701D.


Assuntos
Epistasia Genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Vírus da Influenza A Subtipo H1N1/crescimento & desenvolvimento , Influenza Humana/virologia , Proteínas Virais/genética , Animais , Embrião de Galinha , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Humanos , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H1N1/metabolismo , Vacinas contra Influenza/genética , Vacinas contra Influenza/metabolismo , Vírus Reordenados/genética , Vírus Reordenados/crescimento & desenvolvimento , Vírus Reordenados/metabolismo , Temperatura , Proteínas Virais/metabolismo
15.
J Virol ; 92(13)2018 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-29695422

RESUMO

Bunyaviruses pose a significant threat to human health, prosperity, and food security. In response to viral infections, interferons (IFNs) upregulate the expression of hundreds of interferon-stimulated genes (ISGs), whose cumulative action can potently inhibit the replication of bunyaviruses. We used a flow cytometry-based method to screen the ability of ∼500 unique ISGs from humans and rhesus macaques to inhibit the replication of Bunyamwera orthobunyavirus (BUNV), the prototype of both the Peribunyaviridae family and the Bunyavirales order. Candidates possessing antibunyaviral activity were further examined using a panel of divergent bunyaviruses. Interestingly, one candidate, ISG20, exhibited potent antibunyaviral activity against most viruses examined from the Peribunyaviridae, Hantaviridae, and Nairoviridae families, whereas phleboviruses (Phenuiviridae) largely escaped inhibition. Similar to the case against other viruses known to be targeted by ISG20, the antibunyaviral activity of ISG20 is dependent upon its functional RNase activity. Through use of an infectious virus-like particle (VLP) assay (based on the BUNV minigenome system), we confirmed that gene expression from all 3 viral segments is strongly inhibited by ISG20. Using in vitro evolution, we generated a substantially ISG20-resistant BUNV and mapped the determinants of ISG20 sensitivity/resistance. Taking all the data together, we report that ISG20 is a broad and potent antibunyaviral factor but that some bunyaviruses are remarkably ISG20 resistant. Thus, ISG20 sensitivity/resistance may influence the pathogenesis of bunyaviruses, many of which are emerging viruses of clinical or veterinary significance.IMPORTANCE There are hundreds of bunyaviruses, many of which cause life-threatening acute diseases in humans and livestock. The interferon (IFN) system is a key component of innate immunity, and type I IFNs limit bunyaviral propagation both in vitro and in vivo Type I IFN signaling results in the upregulation of hundreds of IFN-stimulated genes (ISGs), whose concerted action generates an "antiviral state." Although IFNs are critical in limiting bunyaviral replication and pathogenesis, much is still unknown about which ISGs inhibit bunyaviruses. Using ISG-expression screening, we examined the ability of ∼500 unique ISGs to inhibit Bunyamwera orthobunyavirus (BUNV), the prototypical bunyavirus. Using this approach, we identified ISG20, an interferon-stimulated exonuclease, as a potent inhibitor of BUNV. Interestingly, ISG20 possesses highly selective antibunyaviral activity, with multiple bunyaviruses being potently inhibited while some largely escape inhibition. We speculate that the ability of some bunyaviruses to escape ISG20 may influence their pathogenesis.


Assuntos
Antivirais/farmacologia , Vírus Bunyamwera/patogenicidade , Infecções por Bunyaviridae/prevenção & controle , Exonucleases/farmacologia , Genoma Viral , Interferons/metabolismo , Infecções por Bunyaviridae/metabolismo , Infecções por Bunyaviridae/virologia , Exonucleases/genética , Exorribonucleases , Células HeLa , Ensaios de Triagem em Larga Escala , Humanos
16.
Proc Natl Acad Sci U S A ; 113(14): 3832-7, 2016 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-27001849

RESUMO

Plant respiration constitutes a massive carbon flux to the atmosphere, and a major control on the evolution of the global carbon cycle. It therefore has the potential to modulate levels of climate change due to the human burning of fossil fuels. Neither current physiological nor terrestrial biosphere models adequately describe its short-term temperature response, and even minor differences in the shape of the response curve can significantly impact estimates of ecosystem carbon release and/or storage. Given this, it is critical to establish whether there are predictable patterns in the shape of the respiration-temperature response curve, and thus in the intrinsic temperature sensitivity of respiration across the globe. Analyzing measurements in a comprehensive database for 231 species spanning 7 biomes, we demonstrate that temperature-dependent increases in leaf respiration do not follow a commonly used exponential function. Instead, we find a decelerating function as leaves warm, reflecting a declining sensitivity to higher temperatures that is remarkably uniform across all biomes and plant functional types. Such convergence in the temperature sensitivity of leaf respiration suggests that there are universally applicable controls on the temperature response of plant energy metabolism, such that a single new function can predict the temperature dependence of leaf respiration for global vegetation. This simple function enables straightforward description of plant respiration in the land-surface components of coupled earth system models. Our cross-biome analyses shows significant implications for such fluxes in cold climates, generally projecting lower values compared with previous estimates.


Assuntos
Aclimatação/fisiologia , Respiração Celular/fisiologia , Metabolismo Energético/fisiologia , Folhas de Planta/metabolismo , Árvores/metabolismo , Ciclo do Carbono , Dióxido de Carbono/metabolismo , Mudança Climática , Ecossistema , Temperatura Alta
17.
J Gen Virol ; 99(10): 1444-1452, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30091698

RESUMO

Certain parasitoid wasps are associated with Polydnaviruses, symbiotic viruses that encode virulence factors which are essential to successful parasitization by the wasp of a caterpillar host. Members of one group of Polydnaviruses, the Ichnoviruses, encode a multi-gene family known as Vinnexins. Vinnexins are homologues of insect gap junction genes, and form functional gap junctions that may affect host cell physiology. However, the role of Vinnexins in host pathology and the mechanism by which these affect their caterpillar host are largely unknown. In this article, we generated recombinant baculoviruses to express vinnexins in Spodoptera frugiperda (Sf9) cells. To measure cell physiological changes caused by Vinnexins, cells were probed with a membrane potential-sensitive probe, DiBac4(3), and a pH indicator, carboxyfluorescein diacetate (CFDA). In addition, we utilized carbenoxolone and ouabain, respectively, to probe the role of gap junctions and hemi-channels, and Na+/K+-ATPase in establishing membrane potential in studied cells. Our results indicate that Vinnexins induce cell membrane depolarization and cytoplasmic alkalization to a degree specific to each tested Vinnexin, and that neither Vinnexin hemi-channels nor Na+/K+-ATPase appear to underlie these effects directly. These results hint that members of the Vinnexin protein family may affect host bio-electrical phenomena to disrupt host cell physiology, and that the individual proteins of the family may differentially affect host physiology.


Assuntos
Membrana Celular/efeitos dos fármacos , Conexinas/metabolismo , Potenciais da Membrana/efeitos dos fármacos , Proteínas Virais/metabolismo , Animais , Conexinas/genética , Citoplasma/química , Expressão Gênica , Concentração de Íons de Hidrogênio , Células Sf9 , Spodoptera , Proteínas Virais/genética
18.
BMC Biotechnol ; 18(1): 82, 2018 12 29.
Artigo em Inglês | MEDLINE | ID: mdl-30594166

RESUMO

BACKGROUND: The global market for protein drugs has the highest compound annual growth rate of any pharmaceutical class but their availability, especially outside of the US market, is compromised by the high cost of manufacture and validation compared to traditional chemical drugs. Improvements in transgenic technologies allow valuable proteins to be produced by genetically-modified animals; several therapeutic proteins from such animal bioreactors are already on the market after successful clinical trials and regulatory approval. Chickens have lagged behind mammals in bioreactor development, despite a number of potential advantages, due to the historic difficulty in producing transgenic birds, but the production of therapeutic proteins in egg white of transgenic chickens would substantially lower costs across the entire production cycle compared to traditional cell culture-based production systems. This could lead to more affordable treatments and wider markets, including in developing countries and for animal health applications. RESULTS: Here we report the efficient generation of new transgenic chicken lines to optimize protein production in eggs. As proof-of-concept, we describe the expression, purification and functional characterization of three pharmaceutical proteins, the human cytokine interferon α2a and two species-specific Fc fusions of the cytokine CSF1. CONCLUSION: Our work optimizes and validates a transgenic chicken system for the cost-effective production of pure, high quality, biologically active protein for therapeutics and other applications.


Assuntos
Animais Geneticamente Modificados/genética , Biotecnologia/métodos , Galinhas/genética , Citocinas/genética , Animais , Animais Geneticamente Modificados/metabolismo , Reatores Biológicos/economia , Biotecnologia/economia , Galinhas/metabolismo , Citocinas/economia , Citocinas/metabolismo , Humanos , Interferon-alfa/economia , Interferon-alfa/genética , Interferon-alfa/metabolismo , Fator Estimulador de Colônias de Macrófagos/economia , Fator Estimulador de Colônias de Macrófagos/genética , Fator Estimulador de Colônias de Macrófagos/metabolismo , Proteínas Recombinantes/economia , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
19.
Microb Ecol ; 75(2): 419-433, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28875273

RESUMO

A central challenge in community ecology is understanding the role that phenotypic variation among genotypes plays in structuring host-associated communities. While recent studies have investigated the relationship between plant genotype and the composition of soil microbial communities, the effect of genotype-by-environment interactions on the plant microbiome remains unclear. In this study, we assessed the influence of tree genetics (G), nitrogen (N) form and genotype-by-environment interaction (G x N) on the composition of the root microbiome. Rhizosphere communities (bacteria and fungi) and root-associated fungi (including ectomycorrhizal and saprotrophic guilds) were characterised in two genotypes of Pinus radiata with contrasting physiological responses to exogenous organic or inorganic N supply. Genotype-specific responses to N form influenced the composition of the root microbiome. Specifically, (1) diversity and composition of rhizosphere bacterial and root-associated fungal communities differed between genotypes that had distinct responses to N form, (2) shifts in the relative abundance of individual taxa were driven by the main effects of N form or host genotype and (3) the root microbiome of the P. radiata genotype with the most divergent growth responses to organic and inorganic N was most sensitive to differences in N form. Our results show that intraspecific variation in tree response to N form has significant consequences for the root microbiome of P. radiata, demonstrating the importance of genotype-by-environment interactions in shaping host-associated communities.


Assuntos
Bactérias/isolamento & purificação , Fungos/isolamento & purificação , Microbiota , Nitrogênio/análise , Pinus/genética , Raízes de Plantas/microbiologia , Microbiologia do Solo , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , Fungos/classificação , Fungos/genética , Fungos/metabolismo , Genótipo , Nitrogênio/metabolismo , Pinus/metabolismo , Pinus/microbiologia , Raízes de Plantas/genética , Raízes de Plantas/metabolismo
20.
J Chem Phys ; 148(13): 134702, 2018 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-29626909

RESUMO

The importance of renewable resources is becoming more and more influential on research due to the depletion of fossil fuels. Cost-effective ways of harvesting solar energy should also be at the forefront of these investigations. Cu2ZnSnS4 (CZTS) solar cells are well within the frame of these goals, and a thorough understanding of how they are made and processed synthetically is crucial. The CZTS/CdS heterojunction was examined using photoelectrochemistry and synchrotron radiation (SR) spectroscopy. These tools provided physical insights into this interface that was formed by the electrophoretic deposition of CZTS nanocrystals and chemical bath deposition (CBD) of CdS for the respective films. It was discovered that CBD induced a change in the local and long range environment of the Zn in the CZTS lattice, which was detrimental to the photoresponse. X-ray absorption near-edge structures and extended X-ray absorption fine structures (EXAFSs) of the junction showed that this change was at an atomic level and was associated with the coordination of oxygen to zinc. This was confirmed through FEFF fitting of the EXAFS and through IR spectroscopy. It was found that this change in both photoresponse and the Zn coordination can be reversed with the use of low temperature annealing. Investigating CZTS through SR techniques provides detailed structural information of minor changes from the zinc perspective.

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