RESUMEN
Previous studies have shown that the Eurasian avian-like H1N1 (EA H1N1) swine influenza viruses circulated widely in pigs around the world and formed multiple genotypes by acquiring non-hemagglutinin and neuraminidase segments derived from other swine influenza viruses. Swine influenza control is not a priority for the pig industry in many countries, and it is worrisome that some strains may become more pathogenic and/or transmissible during their circulation in nature. Our routine surveillance indicated that the EA H1N1 viruses obtained different internal genes from different swine influenza viruses and formed various new genotypes. In this study, we found that a naturally isolated swine influenza reassortant, A/swine/Liaoning/265/2017 (LN265), a representative strain of one of the predominant genotypes in recent years, is lethal in mice and transmissible in ferrets. LN265 contains the hemagglutinin, neuraminidase, and matrix of the EA H1N1 virus; the basic polymerase 2, basic polymerase 1, acidic polymerase (PA), and nucleoprotein of the 2009 H1N1 pandemic virus; and the nonstructural protein of the North American triple-reassortment H1N2 virus. By generating and testing a series of reassortants and mutants, we found that four gradually accumulated mutations in PA are responsible for the increased pathogenicity and transmissibility of LN265. We further revealed that these mutations increase the messenger RNA transcription of viral proteins by enhancing the endonuclease cleavage activity and viral RNA-binding ability of the PA protein. Our study demonstrates that EA H1N1 swine influenza virus became pathogenic and transmissible in ferrets by acquiring key mutations in PA and provides important insights for monitoring field strains with pandemic potential.
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Subtipo H1N1 del Virus de la Influenza A , Infecciones por Orthomyxoviridae , ARN Polimerasa Dependiente del ARN , Enfermedades de los Porcinos , Animales , Hurones , Genotipo , Subtipo H1N1 del Virus de la Influenza A/genética , Subtipo H1N1 del Virus de la Influenza A/patogenicidad , Ratones , Mutación , Neuraminidasa/genética , Infecciones por Orthomyxoviridae/veterinaria , Infecciones por Orthomyxoviridae/virología , Filogenia , ARN Polimerasa Dependiente del ARN/genética , Virus Reordenados/genética , Porcinos , Enfermedades de los Porcinos/virología , Proteínas Virales/genéticaRESUMEN
Host defense systems employ posttranslational modifications to protect against invading pathogens. Here, we found that protein inhibitor of activated STAT 1 (PIAS1) interacts with the nucleoprotein (NP), polymerase basic protein 1 (PB1), and polymerase basic protein 2 (PB2) of influenza A virus (IAV). Lentiviral-mediated stable overexpression of PIAS1 dramatically suppressed the replication of IAV, whereas siRNA knockdown or CRISPR/Cas9 knockout of PIAS1 expression significantly increased virus growth. The expression of PIAS1 was significantly induced upon IAV infection in both cell culture and mice, and PIAS1 was involved in the overall increase in cellular SUMOylation induced by IAV infection. We found that PIAS1 inhibited the activity of the viral RNP complex, whereas the C351S or W372A mutant of PIAS1, which lacks the SUMO E3 ligase activity, lost the ability to suppress the activity of the viral RNP complex. Notably, the SUMO E3 ligase activity of PIAS1 catalyzed robust SUMOylation of PB2, but had no role in PB1 SUMOylation and a minimal role in NP SUMOylation. Moreover, PIAS1-mediated SUMOylation remarkably reduced the stability of IAV PB2. When tested in vivo, we found that the downregulation of Pias1 expression in mice enhanced the growth and virulence of IAV. Together, our findings define PIAS1 as a restriction factor for the replication and pathogenesis of IAV.
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Virus de la Influenza A , Proteínas Inhibidoras de STAT Activados , Sumoilación , Replicación Viral , Animales , Virus de la Influenza A/patogenicidad , Virus de la Influenza A/fisiología , Ratones , Proteínas Inhibidoras de STAT Activados/genética , Proteínas Inhibidoras de STAT Activados/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , VirulenciaRESUMEN
The escalating impact of climate change and ultraviolet (UV) radiation is subjecting plants to unique combinations of UV-B and drought stress. These combined stressors could have additive, synergistic, or antagonistic effects, but the precise nature of these impacts remains uncertain, hampering our ability to predict plant adaptations approach towards stressors. Our analysis of various studies shows that UV-B or drought conditions detrimentally influence plant growth and health metrics by the enhanced generation of reactive oxygen species causing damage to lipids, proteins, carbohydrates and DNA. Further reducing biomass accumulation, plant height, photosynthetic efficiency, leaf area, and water transpiration, while enhancing stress-related symptoms. In response to UV-B radiation and drought stress, plants exhibit a notable up-regulation of specific acclimation-associated metabolites, including proline, flavonoids, anthocyanins, unsaturated fatty acids, and antioxidants. These metabolites play a pivotal role in conferring protection against environmental stresses. Their biosynthesis and functional roles are potentially modulated by signalling molecules such as hydrogen peroxide, abscisic acid, jasmonic acid, salicylic acid, and ethylene, all of which have associated genetic markers that further elucidate their involvement in stress response pathways. In comparison to single stress, the combination of UV-B and drought induces the plant defence responses and growth retardation which are less-than-additive. This sub-additive response, consistent across different study environments, suggests the possibility of a cross-resistance mechanism. Our outlines imply that the adverse effects of increased drought and UV-B could potentially be mitigated by cross-talk between UV-B and drought regimes utilizing a multidimensional approach. This crucial insight could contribute significantly to refining our understanding of stress tolerance in the face of ongoing global climate change.
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Antocianinas , Resiliencia Psicológica , Sequías , Plantas/efectos de la radiación , Estrés Fisiológico/genéticaRESUMEN
Maintaining appropriate intracellular calcium of oocytes is necessary to prevent ultrastructure and organelle damage caused by freezing and cryoprotectants. The present study aimed to investigate whether cryoprotectant-induced changes in the calcium concentrations of oocytes can be regulated to reduce damage to developmental potential and ultrastructure. A total of 33 mice and 1381 oocytes were used to explore the effects of intracellular calcium on the development and ultrastructures of oocytes subjected to 2-aminoethoxydiphenyl borate (2-APB) inhibition or thapsigargin (TG) stimulation. Results suggested that high levels intracellular calcium interfered with TG compromised oocyte survival (84.4 % vs. 93.4 %, p < 0.01) and blastocyst formation in fresh and cryopreservation oocytes (78.1 % vs. 86.4 %, and 60.5 % vs. 72.5 %, p < 0.05) compared with that of 2-APB pretreated oocytes in which Ca2+ was stabilized even though no differences in fertilization and cleavage was detected (p > 0.05). Examination by transmission electron microscopy indicated that the microvilli decreased and shortened, cortical granules considerably decreased in the cortex area, mitochondrial vesicles and vacuoles increased, and the proportion of vacuole mitochondria increased after oocytes were exposed to cryoprotectants. The cryopreservation-warming process deteriorated the negative effects on organelles of survival oocytes. By contrast, a low level of intracellular calcium mediated with 2-APB was supposed to contribute to the protection of organelles. These findings suggested oocyte injuries induced by cryoprotectants and low temperatures can be alleviated. More studies are necessary to confirm the relationship among Ca2+ concentration of the cytoplasm, ultrastructural injuries, and disrupted developmental potential in oocytes subjected to cryopreservation and warming.
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Calcio , Criopreservación , Animales , Ratones , Criopreservación/métodos , Calcio/farmacología , Oocitos , Congelación , Crioprotectores/farmacologíaRESUMEN
In order to study the toxic effect and mechanism of triptolide(TP) on the reproductive system of female rats with â ¡ type collagen induced arthritis(CIA), 50 SD rats were randomly divided into normal control group, CIA model group, and three groups receiving TP tablets at clinically equivalent doses of 0. 5, 1, and 2 times, respectively(with TP dosages of 3. 75, 7. 5, and 15 µg·kg~(-1)·d~(-1)), each comprising 10 rats. Intragastric administration was started on the day after the first immunization, once a day, for 42 days.The results were taken on the 21st and 42nd days to calculate the uterine and ovarian organ indexes; pathological and morphological changes in uterus and ovaries were observed under a light microscope; and the levels of estradiol(E_2) and cytochrome P450A1(aromatase,CYP19A1) in ovarian homogenate were detected by ELISA. Furthermore, immunohistochemistry was employed to detect the expression levels of transforming growth factor ß3( TGFß3) pathway-related proteins, mothers against decapentaplegic homolog 3(Smad3) and steroidogenic factor-1(SF-1) in ovarian tissues. In vitro, the mouse Chinese hamster ovary(CHO) cell line was established, and after 24 hours of TP administration(30, 60, 120 nmol·L~(-1)), cell proliferation was detected by the thiazolyl blue tetrazolium bromide(MTT) method, apoptosis by the flow cytometry, and TGFß3, Smad3 and SF-1 protein expression in cells by the Western blot method, and the nuclear entry of SF-1 was detected by immunofluorescence. The results showed that compared with the CIA model group, all TP administration groups showed decreased number of uterine glands, total follicles, mature follicles, and corpus luteum on days 21 and 42 of administration, but there was no statistical difference, and only the administration of 2 times the clinically equivalent dose of TP could significantly increase the number of atretic follicles at 42 days of administration. TP at 3. 75 µg·kg-1·d-1significantly reduced the level of E_2 at 21 days of administration and the expression of TGFß3 and Smad3 factors in ovarian tissues,but had no significant effect on the rate-limiting enzyme in estrogen synthesis CYP19A1. TP at 7. 5 and 15 µg·kg~(-1)·d~(-1) significantly reduced the expression of SF-1 regardless of administration for 21 days or 42 days. TP can significantly promote ovarian cell apoptosis in vitro, with apoptosis mainly concentrated in the late stage of apoptosis after 24 hours of administration. In addition, 60 nmol·L~(-1) TP significantly reduced the protein expression of TGFß3, Smad3 and SF-1 in a dose-dependent manner. In summary, intragastric administration of TP at less than 2 times the clinically equivalent dose for 21 days and 42 days did not cause obvious reproductive damage to the uterus and ovarian tissues of CIA rats, and the number of atretic follicles changed significantly only when the 2 times the clinically equivalent dose was administered for 42 days. TP exerted reproductive toxicity in vivo on reproductive target organs and in vitro on ovarian cells by inhibiting the expression of TGFß3/Smad3/SF-1 pathway.
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Diterpenos , Compuestos Epoxi , Ovario , Fenantrenos , Ratas Sprague-Dawley , Útero , Animales , Femenino , Diterpenos/farmacología , Fenantrenos/toxicidad , Ratas , Compuestos Epoxi/toxicidad , Compuestos Epoxi/administración & dosificación , Ovario/efectos de los fármacos , Ovario/metabolismo , Útero/efectos de los fármacos , Útero/metabolismo , Colágeno Tipo II/metabolismo , Proteína smad3/metabolismo , Proteína smad3/genética , Humanos , Reproducción/efectos de los fármacos , Artritis Experimental/tratamiento farmacológico , Artritis Experimental/metabolismo , EstradiolRESUMEN
Highly pathogenic avian influenza (HPAI) subtype H5N1 clade 2.3.4.4b virus has spread globally, causing unprecedented large-scale avian influenza outbreaks since 2020. In 2021, we isolated 17 highly pathogenic avian influenza H5N1 viruses from wild birds in China. To determine virus origin, we genetically analyzed 1,529 clade 2.3.4.4b H5N1 viruses reported globally since October 2020 and found that they formed 35 genotypes. The 17 viruses belonged to genotypes G07, which originated from eastern Asia, and G10, which originated from Russia. The viruses were moderately pathogenic in mice but were highly lethal in ducks. The viruses were in the same antigenic cluster as the current vaccine strain (H5-Re14) used in China. In chickens, the H5/H7 trivalent vaccine provided complete protection against clade 2.3.4.4b H5N1 virus challenge. Our data indicate that vaccination is an effective strategy for preventing and controlling the globally prevalent clade 2.3.4.4b H5N1 virus.
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Subtipo H5N1 del Virus de la Influenza A , Virus de la Influenza A , Gripe Aviar , Animales , Ratones , Subtipo H5N1 del Virus de la Influenza A/genética , Pollos , Animales Salvajes , Virus de la Influenza A/genética , China/epidemiología , FilogeniaRESUMEN
The growing opportunities recognized for covalent drug inhibitors, like KRAS G12C inhibitors, are driving the need for mass spectrometry methods that can quickly and robustly measure therapeutic drug activity in vivo for drug discovery research and development. Effective front-end sample preparation is critical for proteins extracted from tumors but is generally labor intensive and impractical for large sample numbers typical in pharmacodynamic (PD) studies. Herein, we describe an automated and integrated sample preparation method for the measurement of activity levels of KRAS G12C drug inhibitor alkylation from complex tumor samples involving high throughput detergent removal and preconcentration followed by quantitation using mass spectrometry. We introduce a robust assay with an average intra-assay coefficient of variation (CV) of 4% and an interassay CV of 6% obtained from seven studies, enabling us to understand the relationship between KRAS G12C target occupancy and the therapeutic PD effect from mouse tumor samples. Further, the data demonstrated that the drug candidate GDC-6036, a KRAS G12C covalent inhibitor, shows dose-dependent target inhibition (KRAS G12C alkylation) and MAPK pathway inhibition, which correlate with high antitumor potency in the MIA PaCa-2 pancreatic xenograft model.
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Antineoplásicos , Proteínas Proto-Oncogénicas p21(ras) , Humanos , Animales , Ratones , Proteínas Proto-Oncogénicas p21(ras)/genética , Línea Celular Tumoral , Mutación , Antineoplásicos/farmacología , Modelos Animales de EnfermedadRESUMEN
The matrix protein (M1) of influenza A virus plays an important role in replication, assembly, and budding. A previous study found that aspartic acid (D) at position 30 and alanine (A) at position 215 of M1 contribute to the high pathogenicity of H5N1 viruses in mice, and double mutations of D to asparagine (N) at position 30 (D30N) and A to threonine (T) at position 215 (A215T) in M1 dramatically attenuate H5N1 viruses in mice. However, the underlying mechanisms by which these M1 mutations attenuate the virulence of H5N1 viruses are unknown. Here, we found that the amino acid mutation A215T eliminates the SUMOylation of M1 by reducing its interaction with the host SUMO1 protein, significantly reducing the stability of M1, slowing the export of the M1-vRNP complex from the nucleus to the cytoplasm, and reducing viral replication in MDCK cells. We further found that the D30N mutation in M1 alters the shape of progeny viruses from filamentous to spherical virions. Our findings reveal an essential role for M1 215A SUMOylation and M1 30D-related filamentous morphology in the pathogenesis of avian influenza viruses, which could be targeted in novel antiviral drug designs. IMPORTANCE Identification of the pathogenic mechanism of highly pathogenic avian influenza viruses in mammals is helpful to develop novel anti-influenza virus strategies. Two amino acid mutations (D30N and A215T) in M1 were found to collectively attenuate H5N1 influenza viruses in mice, but the underlying mechanism remained unknown. This study found that the A215T mutation significantly decreases the SUMOylation of M1, which in turn attenuates the replication of H5N1 virus in mammalian cells. The D30N mutation in M1 was found to change the virion shape from filamentous to spherical. These findings are important for understanding the molecular mechanism of virulence of highly pathogenic avian influenza viruses in mammals.
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Subtipo H5N1 del Virus de la Influenza A/fisiología , Subtipo H5N1 del Virus de la Influenza A/patogenicidad , Infecciones por Orthomyxoviridae/virología , Proteínas de la Matriz Viral/metabolismo , Replicación Viral , Transporte Activo de Núcleo Celular , Animales , Núcleo Celular/metabolismo , Perros , Subtipo H5N1 del Virus de la Influenza A/metabolismo , Subtipo H5N1 del Virus de la Influenza A/ultraestructura , Células de Riñón Canino Madin Darby , Ratones , Mutación , Infecciones por Orthomyxoviridae/metabolismo , Estabilidad Proteica , Ribonucleoproteínas/metabolismo , Sumoilación , Proteínas de la Matriz Viral/genética , Virión/ultraestructura , Virulencia/genética , Replicación Viral/genéticaRESUMEN
The H7N9 avian influenza virus (AIV) that emerged in China have caused five waves of human infection. Further human cases have been successfully prevented since September 2017 through the use of an H7N9 vaccine in poultry. However, the H7N9 AIV has not been eradicated from poultry in China, and its evolution remains largely unexplored. In this study, we isolated 19 H7N9 AIVs during surveillance and diagnosis from February 2018 to December 2019, and genetic analysis showed that these viruses have formed two different genotypes. Animal studies indicated that the H7N9 viruses are highly lethal to chicken, cause mild infection in ducks, but have distinct pathotypes in mice. The viruses bound to avian-type receptors with high affinity, but gradually lost their ability to bind to human-type receptors. Importantly, we found that H7N9 AIVs isolated in 2019 were antigenically different from the H7N9 vaccine strain that was used for H7N9 influenza control in poultry, and that replication of these viruses cannot, therefore, be completely prevented in vaccinated chickens. We further revealed that two amino acid mutations at positions 135 and 160 in the HA protein added two glycosylation sites and facilitated the escape of the H7N9 viruses from the vaccine-induced immunity. Our study provides important insights into H7N9 virus evolution and control.
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Subtipo H7N9 del Virus de la Influenza A/genética , Subtipo H7N9 del Virus de la Influenza A/aislamiento & purificación , Vacunas contra la Influenza/uso terapéutico , Gripe Aviar/prevención & control , Enfermedades de las Aves de Corral/virología , Animales , Animales de Zoológico/virología , Pollos/virología , China/epidemiología , Patos/virología , Control de Infecciones/métodos , Subtipo H7N9 del Virus de la Influenza A/clasificación , Subtipo H7N9 del Virus de la Influenza A/fisiología , Gripe Aviar/epidemiología , Gripe Aviar/virología , Ratones , Filogenia , Vigilancia de la Población , Aves de Corral , Enfermedades de las Aves de Corral/epidemiología , Enfermedades de las Aves de Corral/prevención & controlRESUMEN
Posttranslational modifications, such as SUMOylation, play specific roles in the life cycle of invading pathogens. However, the effect of SUMOylation on the adaptation, pathogenesis, and transmission of influenza A virus (IAV) remains largely unknown. Here, we found that a conserved lysine residue at position 612 (K612) of the polymerase basic protein 1 (PB1) of IAV is a bona fide SUMOylation site. SUMOylation of PB1 at K612 had no effect on the stability or cellular localization of PB1, but was critical for viral ribonucleoprotein (vRNP) complex activity and virus replication in vitro. When tested in vivo, we found that the virulence of SUMOylation-defective PB1/K612R mutant IAVs was highly attenuated in mice. Moreover, the airborne transmission of a 2009 pandemic H1N1 PB1/K612R mutant virus was impaired in ferrets, resulting in reversion to wild-type PB1 K612. Mechanistically, SUMOylation at K612 was essential for PB1 to act as the enzymatic core of the viral polymerase by preserving its ability to bind viral RNA. Our study reveals an essential role for PB1 K612 SUMOylation in the pathogenesis and transmission of IAVs, which can be targeted for the design of anti-influenza therapies.
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Virus de la Influenza A/patogenicidad , Infecciones por Orthomyxoviridae/patología , Infecciones por Orthomyxoviridae/transmisión , ARN Viral/metabolismo , Sumoilación , Proteínas Virales/metabolismo , Replicación Viral , Animales , Perros , Femenino , Hurones , Ratones , Ratones Endogámicos BALB C , Infecciones por Orthomyxoviridae/virología , ARN Viral/genética , Proteínas Virales/química , Proteínas Virales/genética , Acoplamiento ViralRESUMEN
The H10 subtypes of avian influenza viruses pose a continual threat to the poultry industry and human health. The sporadic spillover of H10 subtypes viruses from poultry to humans is represented by the H10N8 human cases in 2013 and the recent H10N3 human infection in 2021. However, the genesis and characteristics of the recent reassortment H10N3 viruses have not been systemically investigated. In this study, we characterized 20 H10N3 viruses isolated in live poultry markets during routine nationwide surveillance in China from 2014 to 2021. The viruses in the recent reassortant genotype acquired their hemagglutinin (HA) and neuraminidase (NA) genes from the duck H10 viruses and H7N3 viruses, respectively, whereas the internal genes were derived from chicken H9N2 viruses as early as 2019. Receptor-binding analysis indicated that two of the tested H10N3 viruses had a higher affinity for human-type receptors than for avian-type receptors, highlighting the potential risk of avian-to-human transmission. Animal studies showed that only viruses belonging to the recent reassortant genotype were pathogenic in mice; two tested viruses transmitted via direct contact and one virus transmitted by respiratory droplets in guinea pigs, though with limited efficiency. These findings emphasize the need for enhanced surveillance of H10N3 viruses.
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Subtipo H9N2 del Virus de la Influenza A , Gripe Aviar , Gripe Humana , Humanos , Animales , Cobayas , Ratones , Subtipo H9N2 del Virus de la Influenza A/genética , Subtipo H7N3 del Virus de la Influenza A , Aves de Corral , Pollos , China/epidemiología , Filogenia , Virus Reordenados/genéticaRESUMEN
BackgroundTwo human cases of avian influenza A (H3N8) virus infection were reported in China in 2022.AimTo characterise H3N8 viruses circulating in China in September 2021-May 2022.MethodsWe sampled poultry and poultry-related environments in 25 Chinese provinces. After isolating H3N8 viruses, whole genome sequences were obtained for molecular and phylogenetic analyses. The specificity of H3N8 viruses towards human or avian receptors was assessed in vitro. Their ability to replicate in chicken and mice, and to transmit between guinea pigs was also investigated.ResultsIn total, 98 H3N8 avian influenza virus isolates were retrieved from 38,639 samples; genetic analysis of 31 representative isolates revealed 17 genotypes. Viruses belonging to 10 of these genotypes had six internal genes originating from influenza A (H9N2) viruses. These reassorted viruses could be found in live poultry markets and comprised the strains responsible for the two human infections. A subset of nine H3N8 viruses (including six reassorted) that replicated efficiently in mice bound to both avian-type and human-type receptors in vitro. Three reassorted viruses were shed by chickens for up to 9 days, replicating efficiently in their upper respiratory tract. Five reassorted viruses tested on guinea pigs were transmissible among these by respiratory droplets.ConclusionAvian H3N8 viruses with H9N2 virus internal genes, causing two human infections, occurred in live poultry markets in China. The low pathogenicity of H3N8 viruses in poultry allows their continuous circulation with potential for reassortment. Careful monitoring of spill-over infections in humans is important to strengthen early-warning systems and maintain influenza pandemic preparedness.
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Subtipo H3N8 del Virus de la Influenza A , Subtipo H9N2 del Virus de la Influenza A , Gripe Aviar , Gripe Humana , Enfermedades de las Aves de Corral , Animales , Humanos , Ratones , Cobayas , Gripe Humana/epidemiología , Aves de Corral , Gripe Aviar/epidemiología , Subtipo H9N2 del Virus de la Influenza A/genética , Filogenia , Pollos , China/epidemiología , Enfermedades de las Aves de Corral/epidemiologíaRESUMEN
Predicting the brain penetration of drugs has been notoriously difficult; however, recently, permeability-limited brain models have been constructed. Lead optimization for central nervous system compounds often focuses on compounds that have low transporter efflux, where passive permeability could be a main driver in determining cerebrospinal fluid (CSF)/brain concentrations. The main objective of this study was to evaluate the translatability of passive permeability data generated from different in vitro systems and its impact on the prediction of human CSF/brain concentrations using physiologically-based pharmacokinetic (PBPK) modeling. In vitro data were generated using gMDCK and parallel artificial membrane permeability assay-blood-brain barrier for comparison and predictions using a quantitative structure-activity relationship model were also evaluated. PBPK modeling was then performed for seven compounds with moderate-high permeability and a range of efflux in vitro, and the CSF/brain mass concentrations and Kpuu were reasonably predicted. This work provides the first step of a promising approach using bottom-up PBPK modeling for CSF/brain penetration prediction to support lead optimization and clinical candidate selection.
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Barrera Hematoencefálica , Encéfalo , Humanos , Barrera Hematoencefálica/fisiología , Transporte Biológico , Permeabilidad de la Membrana Celular , Proteínas de Transporte de Membrana , Modelos BiológicosRESUMEN
[This corrects the article DOI: 10.1371/journal.ppat.1004508.].
RESUMEN
Afforestation is an effective approach to rehabilitate degraded ecosystems, but often depletes deep soil moisture. Presently, it is not known how an afforestation-induced decrease in moisture affects soil microbial community and functionality, hindering our ability to understand the sustainability of the rehabilitated ecosystems. To address this issue, we examined the impacts of 20 years of afforestation on soil bacterial community, co-occurrence pattern, and functionalities along vertical profile (0-500 cm depth) in a semiarid region of China's Loess Plateau. We showed that the effects of afforestation with a deep-rooted legume tree on cropland were greater in deep than that of in top layers, resulting in decreased bacterial beta diversity, more responsive bacterial taxa and functional groups, increased homogeneous selection, and decreased network robustness in deep soils (120-500 cm). Organic carbon and nitrogen decomposition rates and multifunctionality also significantly decreased by afforestation, and microbial carbon limitation significantly increased in deep soils. Moreover, changes in microbial community and functionality in deep layer was largely related to changes in soil moisture. Such negative impacts on deep soils should be fully considered for assessing afforestation's eco-environment effects and for the sustainability of ecosystems because deep soils have important influence on forest ecosystems in semiarid and arid climates.
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Ecosistema , Suelo , Bacterias/metabolismo , Carbono/análisis , China , Bosques , Nitrógeno/análisis , Microbiología del SueloRESUMEN
Maternal exposure to chemical elements, including essential and non-essential elements, have been found to be associated with preterm births (PTB). However, few studies have measured element concentrations in cord whole blood, which reflects activity at the maternal-fetal interface and may be biologically associated with PTBs. In this study, we determined concentrations of 21 elements in cord whole blood and explored the associations between element concentrations and PTB in a nested case-control study within a birth cohort in Guangdong, China. Finally, 515 preterm infants and 595 full-term infants were included. We performed single-element and multi-element logistic regressions to evaluate linear relationships between element concentrations and PTB. According to the results of single-element models, most essential elements (including K, Ca, Si, Zn, Se, Sr and Fe) were negatively associated with PTB, while Cu, V, Co and Sn were positively associated with PTB. Of the non-essential elements, Sb, Tl, and U were positively associated with PTB, while Pb was negatively associated with PTB. The multi-element model results for most elements were similar, except that the association between Mg and PTB was shown to be significantly positive, and the association for Cu became much larger. A possible explanation is that the effects of Mg and Cu may be influenced by other elements. We performed restricted cubic spline (RCS) regressions and found significantly non-linear exposure-response relationships for Mg, Se, Sr, K and Sb, indicating that the effects of these elements on PTB are not simply detrimental or beneficial. We also examined the joint effect using a Bayesian kernel machine regression (BKMR) model and found the risk of PTB decreased significantly with element mixture concentration when lnC was larger than the median. Bivariate interaction analysis suggested antagonistic effects of Sb on Zn and Sr, which may be attributed to Sb negating the antioxidant capacity of Zn and Sr. This study provides additional evidence for the effect of element exposures on PTB, and will have implications for the prevention of excessive exposures or inappropriate element supplementation during pregnancy.
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Nacimiento Prematuro , Humanos , Recién Nacido , Embarazo , Femenino , Nacimiento Prematuro/epidemiología , Mujeres Embarazadas , Estudios de Casos y Controles , Teorema de Bayes , Recien Nacido Prematuro , China/epidemiologíaRESUMEN
This study aimed to explore the effect of artesunate(ARS) on bone destruction in rheumatoid arthritis(RA) based on the aryl hydrocarbon receptor(AhR)/AhR nucleart ranslocator(ARNT)/NAD(P)H quinone dehydrogenase 1(NQO1) signaling pathway. Macrophage-colony stimulating factor(M-CSF) and receptor activator of nuclear factor-κB(RANKL) were used to induce the differentiation of primary bone marrow-derived mouse macrophages into osteoclasts. After intervention with ARS(0.2, 0.4, and 0.8 µmol·L~(-1)), the formation and differentiation of osteoclasts were observed by tartrate-resistant acid phosphatase(TRAP) and F-actin staining. The protein expression levels of AhR and NQO1 were detected by Western blot, and their distribution in osteoclasts was observed by immunofluorescence localization. Simultaneously, the collagen induced arthritis(CIA) rat model was established using type â ¡ bovine collagen emulsion and then treated with ARS(7.5, 15, and 30 mg·kg~(-1)) by gavage for 30 days. Following the observation of spinal cord and bone destruction in CIA rats by Masson staining, the expression of AhR and ARNT in rat knee joint tissue was measured by immunohistochemistry and the NQO1 protein expression in the knee joint tissue by Western blot. The results showed that a large number of TRAP-positive cells were present in RANKL-induced rats. Compared with the RANKL-induced group, ARS(0.2, 0.4, and 0.8 µmol·L~(-1)) inhibited the number of TRAP-positive cells in a dose-dependent manner. F-actin staining results showed that the inhibition of F-actin formation was enhanced with the increase in ARS dose. As revealed by Western blot and immunofluorescence assay, ARS significantly promoted the expression of AhR and its transfer to the nucleus, thereby activating the protein expression of downstream ARNT and antioxidant enzyme NQO1. At the same time, the CIA rat model was successfully established. Masson staining revealed serious joint destruction in the model group, manifested by the failed staining of surface cartilage, disordered arrangement of collagen fibers, and unclear boundaries of cartilage and bone. The positive drug and ARS at different doses all improved cartilage and bone destruction to varying degrees, with the best efficacy detected in the high-dose ARS group. According to immunohistochemistry, ARS promoted AhR and ARNT protein expression in knee cartilage and bone of CIA rats and also NQO1 protein expression in rat knee and ankle joint tissues. In conclusion, ARS inhibited osteoclast differentiation by activating the AhR/ARNT/NQO1 signaling pathway, thus alleviating RA.
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Artritis Experimental , Artritis Reumatoide , Actinas/metabolismo , Animales , Artesunato/farmacología , Artritis Experimental/tratamiento farmacológico , Artritis Reumatoide/tratamiento farmacológico , Artritis Reumatoide/genética , Translocador Nuclear del Receptor de Aril Hidrocarburo/metabolismo , Translocador Nuclear del Receptor de Aril Hidrocarburo/farmacología , Bovinos , Colágeno Tipo II/metabolismo , Ratones , NAD(P)H Deshidrogenasa (Quinona)/genética , NAD(P)H Deshidrogenasa (Quinona)/metabolismo , Osteoclastos , Ratas , Transducción de SeñalRESUMEN
Females and males of dioecious plants have evolved sex-specific characteristics in terms of their morphological and physiological properties. However, the differentiation of phyllosphere microbiota in dioecious plants remains largely unexplored. Here, the diversity and composition of female and male Populus cathayana phyllosphere bacterial and fungal communities were investigated using 16S rRNA/ITS1 gene-based MiSeq sequencing. The divergences of bacterial and fungal community compositions occurred between females and males. Both females and males had their unique phyllosphere bacterial and fungal microbiota, such as bacterial Gemmata spp. (5.41%) and fungal Pringsheimia spp. (0.03%) in females and bacterial Chitinophaga spp. (0.009%) and fungal Phaeococcomyces spp. (0.02%) in males. Significant differences in the relative abundance of phyla Proteobacteria and Planctomycetes bacteria and phyla Ascomycota and Basidiomycota fungi (P < 0.05) were also found between females and males. Some bacterial species of genera Spirosoma and Amnibacterium and fungal genera Venturia, Suillus, and Elmerina spp. were significantly enriched in males (P < 0.05). In contrast, levels of fungal genera Phoma and Aureobasidium spp. were significantly higher in females than in males (P < 0.05). The mineral, inorganic, and organic nutrients content contributed differently to the divergence of female and male phyllosphere microbial communities, with 87.08 and 45.17% of the variations being explained for bacterial and fungal communities, respectively. These results highlight the sexual discrimination of phyllosphere microbes on the dioecious plants and provide hints on the potential host-associated species in phyllosphere environments.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
Asunto(s)
Microbiota , Micobioma , Populus , Bacterias/genética , Femenino , Masculino , ARN Ribosómico 16S/genéticaRESUMEN
The low-pathogenic H7N9 influenza viruses that emerged in 2013 acquired an insertion of four amino acids in their hemagglutinin cleavage site and thereby became highly pathogenic to chickens in 2017. Previous studies indicated that these highly pathogenic H7N9 viruses are virulent in chickens but have distinct pathotypes in mice. A/chicken/Guangdong/SD098/2017 (CK/SD098) is avirulent, with a 50% mouse lethal dose (MLD50) of >7.5 log10 50% egg infectious dose (EID50), whereas A/chicken/Hunan/S1220/2017 (CK/S1220) is virulent in mice, with an MLD50 of 3.2 log10 EID50 In this study, we explored the genetic determinants that contribute to the difference in virulence between these two H7N9 viruses by generating a series of reassortants and mutants in the CK/S1220 virus background and testing their virulence in mice. We found that the reassortant CK/1220-SD098-NP, carrying the nucleoprotein (NP) of CK/SD098, was avirulent in mice, with an MLD50 of >107.5 EID50 The NPs of these two viruses differ by two amino acids, at positions 286 and 437. We further demonstrated that the amino acid mutations A286V and T437M of NP independently slowed the process of NP import to and export from the nucleus and thus jointly impaired the viral life cycle and attenuated the virulence of these H7N9 viruses in mice. Our study identified new virulence determinants in NP and provided novel targets for the development of live attenuated vaccines and antiviral drugs against influenza viruses.IMPORTANCE The H7N9 influenza viruses that emerged in China in 2013 have caused over 1,500 human infections, with a mortality rate of nearly 40%. The viruses were initially low pathogenic but became highly pathogenic in chickens at the beginning of 2017 and caused severe disease outbreaks in poultry. Several studies suggested that the highly pathogenic H7N9 viruses have increased virulence in mammals; however, the genetic basis of the virulence of H7N9 viruses in mammals is not fully understood. Here, we found that two amino acids, 286A and 437T, in NP are prerequisites for the virulence of H7N9 viruses in mice and the mutations A286V and T437M collectively eliminate the virulence of H7N9 viruses in mice. Our study further demonstrated that the virulence of influenza viruses is a polygenic trait, and the newly identified virulence-related residues in NP may provide new targets for attenuated influenza vaccine and antiviral drug development.
Asunto(s)
Subtipo H7N9 del Virus de la Influenza A/metabolismo , Subtipo H7N9 del Virus de la Influenza A/patogenicidad , Mutación Missense , Infecciones por Orthomyxoviridae/metabolismo , Proteínas de Unión al ARN/metabolismo , Proteínas del Núcleo Viral/metabolismo , Sustitución de Aminoácidos , Animales , Pollos , Perros , Células HEK293 , Humanos , Subtipo H7N9 del Virus de la Influenza A/genética , Vacunas contra la Influenza/genética , Vacunas contra la Influenza/metabolismo , Células de Riñón Canino Madin Darby , Ratones , Proteínas de la Nucleocápside , Infecciones por Orthomyxoviridae/genética , Proteínas de Unión al ARN/genética , Vacunas Atenuadas/genética , Vacunas Atenuadas/metabolismo , Proteínas del Núcleo Viral/genéticaRESUMEN
Influenza A virus (IAV) coopts numerous host factors to complete its replication cycle. Here, we identify free fatty acid receptor 2 (FFAR2) as a cofactor for IAV entry into host cells. We found that downregulation of FFAR2 or Ffar2 expression significantly reduced the replication of IAV in A549 or RAW 264.7 cells. The treatment of A549 cells with small interfering RNA (siRNA) targeting FFAR2 or the FFAR2 pathway agonists 2-(4-chlorophenyl)-3-methyl-N-(thiazol-2-yl)butanamide (4-CMTB) and compound 58 (Cmp58) [(S)-2-(4-chlorophenyl)-3,3-dimethyl-N-(5-phenylthiazol-2-yl)butanamide] dramatically inhibited the nuclear accumulation of viral nucleoprotein (NP) at early time points postinfection, indicating that FFAR2 functions in the early stage of the IAV replication cycle. FFAR2 downregulation had no effect on the expression of sialic acid (SA) receptors on the cell membrane, the attachment of IAV to the SA receptors, or the activity of the viral ribonucleoprotein (vRNP) complex. Rather, the amount of internalized IAVs was significantly reduced in FFAR2-knocked-down or 4-CMTB- or Cmp58-treated A549 cells. Further studies showed that FFAR2 associated with ß-arrestin1 and that ß-arrestin1 interacted with the ß2-subunit of the AP-2 complex (AP2B1), the essential adaptor of the clathrin-mediated endocytosis pathway. Notably, siRNA knockdown of either ß-arrestin1 or AP2B1 dramatically impaired IAV replication, and AP2B1 knockdown or treatment with Barbadin, an inhibitor targeting the ß-arrestin1/AP2B1 complex, remarkably decreased the amount of internalized IAVs. Moreover, we found that FFAR2 interacted with three G protein-coupled receptor (GPCR) kinases (i.e., GRK2, GRK5, and GRK6) whose downregulation inhibited IAV replication. Together, our findings demonstrate that the FFAR2 signaling cascade is important for the efficient endocytosis of IAV into host cells.IMPORTANCE To complete its replication cycle, IAV hijacks the host endocytosis machinery to invade cells. However, the underlying mechanisms of how IAV is internalized into host cells remain poorly understood, emphasizing the need to elucidate the role of host factors in IAV entry into cells. In this study, we identified FFAR2 as an important host factor for the efficient replication of both low-pathogenic and highly pathogenic IAV. We revealed that FFAR2 facilitates the internalization of IAV into target cells during the early stage of infection. Upon further characterization of the role of FFAR2-associated proteins in virus replication, we found that the FFAR2-ß-arrestin1-AP2B1 signaling cascade is important for the efficient endocytosis of IAV. Our findings thus further our understanding of the biological details of IAV entry into host cells and establish FFAR2 as a potential target for antiviral drug development.