RESUMO
Heterotrimeric G proteins consisting of Gα, Gß and Gγ are conserved signaling hubs in eukaryotes. Without analogs to canonical animal G protein-coupled receptors, plant cells are thought to use RGS1 and a yet unknown mechanism to regulate the activity of Gα. Meanwhile, the exact role of canonical Gα in plant innate immunity remains controversial. Here, we report multiple immune deficiencies in the null allele of Arabidopsis Gα (GPA1) in response to bacterial flg22 elicitor, clarifying a positive regulatory role of GPA1 in flg22 signaling. We also detect overall increased phosphorylation of GPA1 but reduced phosphorylation at Thr19 upon flg22 elicitation. Interestingly, flg22 could not induce phosphorylation of GPA1T19A and GPA1T19D , suggesting that the dynamic Thr19 phosphorylation is required for GPA1 to respond to flg22. Moreover, flg22-induced GPA1 phosphorylation is largely abolished in the absence of BAK1 in vivo, and BAK1 could phosphorylate GPA1 but not GPA1T19A in vitro at the phosphorylation sites identified in vivo, suggesting BAK1 is likely the kinase for GPA1 phosphorylation in response to flg22. Furthermore, the T19A mutation could promote flg22-induced association, rather than dissociation, between GPA1 and RGS1. Taken together, our findings shed new insights into the function and regulation of GPA1 in Arabidopsis defense signaling.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Subunidades alfa de Proteínas de Ligação ao GTP/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Flagelina/genética , Flagelina/metabolismo , Subunidades alfa de Proteínas de Ligação ao GTP/genética , Fosforilação/genética , Fosforilação/fisiologia , Proteínas Serina-Treonina Quinases/genética , Transdução de Sinais/genética , Transdução de Sinais/fisiologiaRESUMO
Heterotrimeric G proteins composed of Gα, Gß and Gγ subunits are evolutionarily conserved signaling modules involved in diverse biological processes in plants and animals. The role and action of Gα remain largely enigmatic in plant innate immunity. We have recently demonstrated that Arabidopsis Gα (GPA1) is a key component of a new immune signaling pathway activated by bacteria-secreted proteases. Here we show that GPA1 is also involved in the signaling network of Arabidopsis in response to the bacterial flagellin epitope flg22. Specifically, GPA1 plays a pivotal role in an immune pathway involving the flg22 receptor FLS2, co-receptor BAK1, Regulator of G Signaling 1 (RGS1), and Arabidopsis Gß (AGB1), in which flg22 elicits GPA1/AGB1 dissociation from the FLS2/BAK1/RGS1 receptor complex. Consequently, we observed flg22-induced degradation of FLS2, BAK1 and RGS1 but not GPA1 or AGB1. We also found that GPA1 constitutively interacts with the NADPH oxidase RbohD to potentiate flg22-induced ROS burst independently of the central cytoplasmic kinase BIK1. Taken together, our work sheds multiple novel insights into the functions and regulatory mechanisms of GPA1 in Arabidopsis innate immunity.
Assuntos
Proteínas de Arabidopsis/imunologia , Arabidopsis/imunologia , Flagelina/imunologia , Subunidades alfa de Proteínas de Ligação ao GTP/imunologia , Imunidade Inata/imunologia , Transdução de Sinais/imunologia , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Epitopos/imunologia , Flagelina/química , Subunidades alfa de Proteínas de Ligação ao GTP/genética , Subunidades alfa de Proteínas de Ligação ao GTP/metabolismo , Subunidades beta da Proteína de Ligação ao GTP/genética , Subunidades beta da Proteína de Ligação ao GTP/imunologia , Subunidades beta da Proteína de Ligação ao GTP/metabolismo , Imunidade Inata/genética , NADPH Oxidases/genética , NADPH Oxidases/imunologia , NADPH Oxidases/metabolismo , Plantas Geneticamente Modificadas , Ligação Proteica , Proteínas Quinases/genética , Proteínas Quinases/imunologia , Proteínas Quinases/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/imunologia , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas RGS/genética , Proteínas RGS/imunologia , Proteínas RGS/metabolismo , Espécies Reativas de Oxigênio/imunologia , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/genéticaRESUMO
BACKGROUND: ALOG (Arabidopsis LSH1 and Oryza G1) family with a conserved domain widely exists in plants. A handful of ALOG members have been functionally characterized, suggesting their roles as key developmental regulators. However, the evolutionary scenario of this gene family during the diversification of plant species remains largely unclear. METHODS: Here, we isolated seven ALOG genes from Torenia fournieri and phylogenetically analyzed them with different ALOG members from representative plants in major taxonomic clades. We further examined their gene expression patterns by RT-PCR, and regarding the protein subcellular localization, we co-expressed the candidates with a nuclear marker. Finally, we explored the functional diversification of two ALOG members, TfALOG1 in euALOG1 and TfALOG2 in euALOG4 sub-clades by obtaining the transgenic T. fournieri plants. RESULTS: The ALOG gene family can be divided into different lineages, indicating that extensive duplication events occurred within eudicots, grasses and bryophytes, respectively. In T. fournieri, seven TfALOG genes from four sub-clades exhibit distinct expression patterns. TfALOG1-6 YFP-fused proteins were accumulated in the nuclear region, while TfALOG7-YFP was localized both in nuclear and cytoplasm, suggesting potentially functional diversification. In the 35S:TfALOG1 transgenic lines, normal development of petal epidermal cells was disrupted, accompanied with changes in the expression of MIXTA-like genes. In 35S:TfALOG2 transgenic lines, the leaf mesophyll cells development was abnormal, favoring functional differences between the two homologous proteins. Unfortunately, we failed to observe any phenotypical changes in the TfALOG1 knock-out mutants, which might be due to functional redundancy as the case in Arabidopsis. CONCLUSION: Our results unraveled the evolutionary history of ALOG gene family, supporting the idea that changes occurred in the cis regulatory and/or nonconserved coding regions of ALOG genes may result in new functions during the establishment of plant architecture.
Assuntos
Evolução Molecular , Lamiales/fisiologia , Proteínas de Plantas/genética , Proteínas de Ligação a RNA/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Duplicação Gênica , Regulação da Expressão Gênica de Plantas , Lamiales/genética , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Família Multigênica , Fenótipo , Filogenia , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Proteínas de Ligação a RNA/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismoRESUMO
The diverse pigmentation patterns of flower corollas probably result from pollinator-mediated selection. Previous studies demonstrated that R2R3-MYB factors may have been recruited in the regulation of corolla pigmentation. However, how R2R3-MYBs became so diverse in their regulation of different pigmentation patterns remains unclear. Here, we studied a Lamiales species, Torenia fournieri, which has elaborate zygomorphic flowers with dorsal-ventral asymmetries in corolla pigmentation. We found recent gene duplication events in CYCLOIDEA-like (CYC-like) and RADIALIS-like (RAD-like) genes, and functionally analyzed three dorsal-specific expression factors: TfCYC1, TfCYC2, and TfRAD1. We found that the CYC-RAD module coordinates petal shape and corolla pigmentation, as ectopic expression of TfCYC2 or TfRAD1 disrupted the asymmetric corolla pigmentation pattern and produced strongly dorsalized flowers. Dorsal petal identity was lost when TfCYC2 was down-regulated or when TfRAD1 was knocked out. In T. fournieri, the diversified CYC and RAD genes have evolved regulatory loops, and TfCYC2 binds directly to the regulatory regions of an R2R3-MYB factor gene, TfMYB1, which might lead to its asymmetric expression and ultimately establish the asymmetric pigmentation pattern. These findings support the existence of a regulatory module that integrates dorsal-ventral patterning and asymmetric corolla pigmentation in T. fournieri.
Assuntos
Flores/anatomia & histologia , Lamiaceae/anatomia & histologia , Lamiaceae/fisiologia , Pigmentação , Proteínas de Plantas/metabolismo , Antocianinas/metabolismo , Vias Biossintéticas/genética , Padronização Corporal , Clonagem Molecular , Flores/genética , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Lamiaceae/genética , Modelos Biológicos , Fenótipo , Filogenia , Proteínas de Plantas/genética , Ligação Proteica , Sequências Reguladoras de Ácido Nucleico/genéticaRESUMO
BACKGROUND: Some species of Marine bacteria pose great risks to human and mariculture organisms. Meanwhile, Vibrio harveyi and Vibrio parahaemolyticus strains have acquired resistance to many antibiotics. OBJECTIVE: A novel series of erythromycin 9-acylhydrazone derivatives were synthesized and evaluated for their in vitro antibacterial activity against marine pathogens. METHODS: The site-selective N-acylation of erythromycin hydrazone was achieved using acid chloride/ triethylamine in methanol as the reaction system. All the synthesized target compounds were evaluated for their antibacterial activity by determination of minimum inhibitory concentrations (MICs) using the broth microdilution method. RESULTS: All the tested acylhydrazone compounds showed moderate to high activity with MIC value 0.125-1 µg/mL against Vibrio parahaemolyticus and Vibrio harveyi. CONCLUSION: The introduction of the acylhydrazone moiety at the C-9 position of erythromycin improved its activity against the above-mentioned marine bacteria strains.
Assuntos
Eritromicina , Vibrio , Humanos , Eritromicina/farmacologia , Antibacterianos/farmacologia , Testes de Sensibilidade MicrobianaRESUMO
In the relentless pursuit of developing high-performance, stable and environmentally friendly materials for X-ray detection, we present a new class of Bi-based hybrid organic-inorganic perovskites. An X-ray detector based on a new zero-dimensional (0D) triiodide-induced lead-free hybrid perovskite, (DPA)2BiI9 (DPA = C5H16N22+), has been developed demonstrating outstanding detection performance, including high X-ray sensitivity (20 570 µC Gyair-1 cm-2), low detectable dose rate (0.98 nGyair s-1), fast response time (154/162 ns) and excellent long-term stability.
RESUMO
Response inhibition, a crucial component of executive function, is closely related to personal impulse control, social adaption, and mental health. Previous studies have found response inhibition deficit in patients with major depressive disorder, but whether it also exists in individuals with subclinical depression (SD) remains unclear. This study aimed to identify the ability of response inhibition to emotional face stimuli both under explicit and implicit conditions in individuals with SD. Thirty-six subclinical depressed college students and 39 healthy individuals were recruited and administered the non-emotional, explicit, and implicit emotional stop-signal tasks (SSTs). Mixed-model analyses of variance were used to analyze the differences between and within groups. In implicit emotional SST, the results showed a significant longer stop-signal response time, a shorter stop-signal delay time, a shorter go reaction time, and a similar proportion of stop success in the SD group compared to healthy controls. However, the above indices showed no significant difference between the two groups in the non-emotional SST and explicit emotional SST. These findings suggest a possible defect of response inhibition in implicit emotional processing in individuals with SD, which may potentially serve as a marker of susceptibility to depression and thus be applied to early screening and intervention for major depressive disorder.
Assuntos
Transtorno Depressivo Maior , Depressão , Emoções/fisiologia , Função Executiva/fisiologia , Humanos , Tempo de Reação/fisiologiaRESUMO
We present a CPU-based real-time cloth animation method for dressing virtual humans of various shapes and poses. Our approach formulates the clothing deformation as a high-dimensional function of body shape parameters and pose parameters. In order to accelerate the computation, our formulation factorizes the clothing deformation into two independent components: the deformation introduced by body pose variation (Clothing Pose Model) and the deformation from body shape variation (Clothing Shape Model). Furthermore, we sample and cluster the poses spanning the entire pose space and use those clusters to efficiently calculate the anchoring points. We also introduce a sensitivity-based distance measurement to both find nearby anchoring points and evaluate their contributions to the final animation. Given a query shape and pose of the virtual agent, we synthesize the resulting clothing deformation by blending the Taylor expansion results of nearby anchoring points. Compared to previous methods, our approach is general and able to add the shape dimension to any clothing pose model. Furthermore, we can animate clothing represented with tens of thousands of vertices at 50+ FPS on a CPU. We also conduct a user evaluation and show that our method can improve a user's perception of dressed virtual agents in an immersive virtual environment (IVE) compared to a realtime linear blend skinning method.
Assuntos
Gráficos por Computador , HumanosRESUMO
Toxoplasma gondii, a protozoan intracellular parasite, is present in a wide range of hosts, including virtually all species of warm-blooded vertebrates. Toxoplasmosis spreads to humans through a variety of pathways, including contaminated food or water, and close contact with various types of domestic animals. It poses a severe threat to human health, and contributes to important economic losses, not only in cost-of-illness but also in surveillance programs. It is thus necessary to develop a rapid point-of-care field diagnostic technology to control or prevent pathogen transmission to economically important livestock animals, domestic animals, and human beings. In this study, we develop a real-time isothermal amplification method capable of detecting the T. gondii genome in swine and feline blood samples. This method can detect toxoplasma genome with a lowest detection limit of 102 copies of per reaction under optimal reaction conditions of 36 °C for 25 min. The assay displayed advantages in sensitivity and specificity in comparison to traditional real-time PCR, and can be performed in a portable instrument.
Assuntos
Doenças do Gato , Técnicas de Amplificação de Ácido Nucleico , Doenças dos Suínos , Toxoplasmose , Animais , Doenças do Gato/diagnóstico , Gatos , DNA de Protozoário/genética , Limite de Detecção , Suínos , Doenças dos Suínos/diagnóstico , Toxoplasma/genética , Toxoplasmose/diagnósticoRESUMO
Living organisms can be primed for potentiated responses to recurring stresses based on prior experience. However, the molecular basis of immune priming remains elusive in plants that lack adaptive immunity. Here, we report that bacterial challenges can prepare plants for fungal attacks by inducing juxtamembrane phosphorylation of CERK1, the co-receptor indispensable for signaling in response to the fungal elicitor chitin. This phosphorylation is mediated by BAK1, a co-receptor for signaling in response to multiple elicitors. BAK1 interacts with CERK1, and loss of BAK1 reduces priming phosphorylation of CERK1. Juxtamembrane phosphomimetic mutations of CERK1 confer accelerated chitin responses and fortified fungal resistance without triggering constitutive immunity, whereas juxtamembrane phosphodeficient mutations diminish bacteria-induced protection against fungal infection. These findings reveal that crosstalk between cell-surface immune co-receptors can prime defense and demonstrate that juxtamembrane phosphorylation of plant receptor-like kinases can occur independent of kinase activation to place the protein into a prime state.