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The intrinsic mechanisms that regulate neurotoxic versus neuroprotective astrocyte phenotypes and their effects on central nervous system degeneration and repair remain poorly understood. Here we show that injured white matter astrocytes differentiate into two distinct C3-positive and C3-negative reactive populations, previously simplified as neurotoxic (A1) and neuroprotective (A2)1,2, which can be further subdivided into unique subpopulations defined by proliferation and differential gene expression signatures. We find the balance of neurotoxic versus neuroprotective astrocytes is regulated by discrete pools of compartmented cyclic adenosine monophosphate derived from soluble adenylyl cyclase and show that proliferating neuroprotective astrocytes inhibit microglial activation and downstream neurotoxic astrocyte differentiation to promote retinal ganglion cell survival. Finally, we report a new, therapeutically tractable viral vector to specifically target optic nerve head astrocytes and show that raising nuclear or depleting cytoplasmic cyclic AMP in reactive astrocytes inhibits deleterious microglial or macrophage cell activation and promotes retinal ganglion cell survival after optic nerve injury. Thus, soluble adenylyl cyclase and compartmented, nuclear- and cytoplasmic-localized cyclic adenosine monophosphate in reactive astrocytes act as a molecular switch for neuroprotective astrocyte reactivity that can be targeted to inhibit microglial activation and neurotoxic astrocyte differentiation to therapeutic effect. These data expand on and define new reactive astrocyte subtypes and represent a step towards the development of gliotherapeutics for the treatment of glaucoma and other optic neuropathies.
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Astrocitos , Neuroprotección , Adenilil Ciclasas/metabolismo , Astrocitos/citología , Astrocitos/enzimología , Astrocitos/metabolismo , Diferenciación Celular , Núcleo Celular/metabolismo , Supervivencia Celular , AMP Cíclico/metabolismo , Citoplasma/metabolismo , Macrófagos/metabolismo , Macrófagos/patología , Microglía/metabolismo , Microglía/patología , Traumatismos del Nervio Óptico/metabolismo , Traumatismos del Nervio Óptico/patología , Traumatismos del Nervio Óptico/terapia , Células Ganglionares de la Retina/citología , Células Ganglionares de la Retina/metabolismo , Sustancia Blanca/metabolismo , Sustancia Blanca/patología , Glaucoma/patología , Glaucoma/terapiaRESUMEN
Despite evidence that γδ T cells play an important role during malaria, their precise role remains unclear. During murine malaria induced by Plasmodium chabaudi infection and in human P. falciparum infection, we found that γδ T cells expanded rapidly after resolution of acute parasitemia, in contrast to αß T cells that expanded at the acute stage and then declined. Single-cell sequencing showed that TRAV15N-1 (Vδ6.3) γδ T cells were clonally expanded in mice and had convergent complementarity-determining region 3 sequences. These γδ T cells expressed specific cytokines, M-CSF, CCL5, CCL3, which are known to act on myeloid cells, indicating that this γδ T cell subset might have distinct functions. Both γδ T cells and M-CSF were necessary for preventing parasitemic recurrence. These findings point to an M-CSF-producing γδ T cell subset that fulfills a specialized protective role in the later stage of malaria infection when αß T cells have declined.
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Factor Estimulante de Colonias de Macrófagos/fisiología , Malaria/prevención & control , Receptores de Antígenos de Linfocitos T gamma-delta/fisiología , Subgrupos de Linfocitos T/inmunología , Animales , Femenino , Humanos , Activación de Linfocitos , Malaria/inmunología , Ratones , Parasitemia/prevención & control , RecurrenciaRESUMEN
Xanthomonas species are major pathogens of plants and have been studied extensively. There is increasing recognition of the importance of non-pathogenic species within the same genus. With this came the need to understand the genomic and functional diversity of non-pathogenic Xanthomonas (NPX) at the species and strain level. This study reports isolation and investigation into the genomic diversity and variation in NPX isolates, chiefly Xanthomonas indica, a newly discovered NPX species from rice. The study establishes the relationship of X. indica strains within clade I of Xanthomonads with another NPX species, X. sontii, also associated with rice seeds. Identification of highly diverse strains, open-pan genome, and systematic hyper-variation at the lipopolysaccharide biosynthetic locus when compared to pathogenic Xanthomonas indicates the acquisition of new functions for adaptation. Furthermore, comparative genomics studies established the absence of major virulence genes such as type III secretion system and effectors, which are present in the pathogens, and the presence of a known bacterial-killing type IV secretion system (X-T4SS). The diverse non-pathogenic strains of X. indica and X. sontii were found to protect rice from bacterial leaf blight pathogen, X. oryzae pv. oryzae (Xoo). The absence of phenotype of an X-T4SS mutant suggests redundancy in the genetic basis of the mechanisms involved in the bioprotection function, which may include multiple genetic loci, such as putative bacteriocin-encoding gene clusters and involvement of other factors such as nutrient and niche competition apart from induction of innate immunity through shared microbial-associated molecular patterns. The rice-NPX community and its pathogenic counterpart can be a promising model for understanding plant-microbe-microbiome interaction studies.IMPORTANCEThe Xanthomonas group of bacteria is known for its characteristic lifestyle as a phytopathogen. However, the discovery of non-pathogenic Xanthomonas (NPX) species is a major shift in understanding this group of bacteria. Multi-strain, in-depth genomic, evolutionary and functional studies on each of these NPX species are still lacking. This study on diverse non-pathogenic strains provides novel insights into genome diversity, dynamics, and evolutionary trends of NPX species from rice microbiome apart from its relationship with other relatives that form a sub-clade. Interestingly, we also uncovered that NPX species protect rice from pathogenic Xanthomonas species. The plant protection property shows their importance as a part of a healthy plant microbiome. Furthermore, finding an open pan-genome and large-scale variation at lipopolysaccharide biosynthetic locus indicates a significant role of the NPX community in host adaptation. The findings and high-quality genomic resources of NPX species and the strains will allow further systematic molecular and host-associated microbial community studies for plant health.
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Enhancing carbohydrate export from source to sink tissues is considered to be a realistic approach for improving photosynthetic efficiency and crop yield. The rice sucrose transporters OsSUT1, OsSWEET11a and OsSWEET14 contribute to sucrose phloem loading and seed filling. Crucially, Xanthomonas oryzae pv. oryzae (Xoo) infection in rice enhances the expression of OsSWEET11a and OsSWEET14 genes, and causes leaf blight. Here we show that co-overexpression of OsSUT1, OsSWEET11a and OsSWEET14 in rice reduced sucrose synthesis and transport leading to lower growth and yield but reduced susceptibility to Xoo relative to controls. The immunity-related hypersensitive response (HR) was enhanced in the transformed lines as indicated by the increased expression of defence genes, higher salicylic acid content and presence of HR lesions on the leaves. The results suggest that the increased expression of OsSWEET11a and OsSWEET14 in rice is perceived as a pathogen (Xoo) attack that triggers HR and results in constitutive activation of plant defences that are related to the signalling pathways of pathogen starvation. These findings provide a mechanistic basis for the trade-off between plant growth and immunity because decreased susceptibility against Xoo compromised plant growth and yield.
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Regulación de la Expresión Génica de las Plantas , Proteínas de Transporte de Membrana , Oryza , Enfermedades de las Plantas , Inmunidad de la Planta , Proteínas de Plantas , Plantas Modificadas Genéticamente , Ácido Salicílico , Sacarosa , Xanthomonas , Oryza/microbiología , Oryza/genética , Oryza/inmunología , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Xanthomonas/fisiología , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/inmunología , Sacarosa/metabolismo , Proteínas de Transporte de Membrana/metabolismo , Proteínas de Transporte de Membrana/genética , Ácido Salicílico/metabolismo , Hojas de la Planta/metabolismo , Hojas de la Planta/inmunologíaRESUMEN
We demonstrate that the time-integrated light intensity transmitted by a coherently driven resonator obeys Lévy's arcsine laws-a cornerstone of extreme value statistics. We show that convergence to the arcsine distribution is algebraic, universal, and independent of nonequilibrium behavior due to nonconservative forces or nonadiabatic driving. We furthermore verify, numerically, that the arcsine laws hold in the presence of frequency noise and in Kerr-nonlinear resonators supporting non-Gaussian states. The arcsine laws imply a weak ergodicity breaking which can be leveraged to enhance the precision of resonant optical sensors with zero energy cost, as shown in our companion manuscript [V. G. Ramesh et al., companion paper, Phys. Rev. Res. (2024).PPRHAI2643-1564]. Finally, we discuss perspectives for probing the possible breakdown of the arcsine laws in systems with memory.
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Loss of retinal ganglion cells (RGCs) is central to the pathogenesis of optic neuropathies such as glaucoma. Increased RGC cAMP signaling is neuroprotective. We have shown that displacement of the cAMP-specific phosphodiesterase PDE4D3 from an RGC perinuclear compartment by expression of the modified PDE4D3 N-terminal peptide 4D3(E) increases perinuclear cAMP and protein kinase A activity in cultured neurons and in vivo RGC survival after optic nerve crush (ONC) injury. To explore mechanisms by which PDE4D3 displacement promotes neuroprotection, in this study mice intravitreally injected with an adeno-associated virus to express an mCherry-tagged 4D3(E) peptide were subjected to ONC injury and analyzed by single cell RNA-sequencing (scRNA-seq). 4D3(E)-mCherry expression was associated with an attenuation of injury-induced changes in gene expression, thereby supporting the hypothesis that enhanced perinuclear PKA signaling promotes neuroprotective RGC gene expression.
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Ratones Endogámicos C57BL , Traumatismos del Nervio Óptico , Células Ganglionares de la Retina , Células Ganglionares de la Retina/metabolismo , Células Ganglionares de la Retina/patología , Células Ganglionares de la Retina/efectos de los fármacos , Animales , Ratones , Traumatismos del Nervio Óptico/metabolismo , Traumatismos del Nervio Óptico/tratamiento farmacológico , Traumatismos del Nervio Óptico/genética , Regulación de la Expresión Génica , Modelos Animales de Enfermedad , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 4/metabolismo , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 4/genética , Compresión Nerviosa , Supervivencia Celular , Inyecciones Intravítreas , Transducción de Señal , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Masculino , Células CultivadasRESUMEN
KEY MESSAGE: By deploying a multi-omics approach, we unraveled the mechanisms that might help rice to combat Yellow Stem Borer infestation, thus providing insights and scope for developing YSB resistant rice varieties. Yellow Stem Borer (YSB), Scirpophaga incertulas (Walker) (Lepidoptera: Crambidae), is a major pest of rice, that can lead to 20-60% loss in rice production. Effective management of YSB infestation is challenged by the non-availability of adequate sources of resistance and poor understanding of resistance mechanisms, thus necessitating studies for generating resources to breed YSB resistant rice and to understand rice-YSB interaction. In this study, by using bulk-segregant analysis in combination with next-generation sequencing, Quantitative Trait Loci (QTL) intervals in five rice chromosomes were mapped that could be associated with YSB resistance at the vegetative phase in a resistant rice line named SM92. Further, multiple SNP markers that showed significant association with YSB resistance in rice chromosomes 1, 5, 10, and 12 were developed. RNA-sequencing of the susceptible and resistant lines revealed several genes present in the candidate QTL intervals to be differentially regulated upon YSB infestation. Comparative transcriptome analysis revealed a putative candidate gene that was predicted to encode an alpha-amylase inhibitor. Analysis of the transcriptome and metabolite profiles further revealed a possible link between phenylpropanoid metabolism and YSB resistance. Taken together, our study provides deeper insights into rice-YSB interaction and enhances the understanding of YSB resistance mechanism. Importantly, a promising breeding line and markers for YSB resistance have been developed that can potentially aid in marker-assisted breeding of YSB resistance among elite rice cultivars.
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Mapeo Cromosómico , Mariposas Nocturnas , Oryza , Sitios de Carácter Cuantitativo , Oryza/genética , Oryza/parasitología , Oryza/inmunología , Animales , Mariposas Nocturnas/fisiología , Polimorfismo de Nucleótido Simple , Enfermedades de las Plantas/parasitología , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/inmunología , Resistencia a la Enfermedad/genética , Genómica/métodos , Fenotipo , MultiómicaRESUMEN
Lodging, a phenomenon characterized by the bending or breaking of rice plants, poses substantial constraints on productivity, particularly during the harvesting phase in regions susceptible to strong winds. The rice strong culm trait is influenced by the intricate interplay of genetic, physiological, epigenetic, and environmental factors. Stem architecture, encompassing morphological and anatomical attributes, alongside the composition of both structural and non-structural carbohydrates, emerges as a critical determinant of lodging resistance. The adaptive response of the rice culm to various biotic and abiotic environmental factors further modulates the propensity for lodging. Advancements in next-generation sequencing technologies have expedited the genetic dissection of lodging resistance, enabling the identification of pertinent genes, quantitative trait loci, and novel alleles. Concurrently, contemporary breeding strategies, ranging from biparental approaches to more sophisticated methods such as multi-parent-based breeding, gene pyramiding, genomic selection, genome-wide association studies, and haplotype-based breeding, offer perspectives on the genetic underpinnings of culm strength. This review comprehensively delves into physiological attributes, culm histology, epigenetic determinants, and gene expression profiles associated with lodging resistance, with a specialized focus on leveraging next-generation sequencing for candidate gene discovery.
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Complete panicle exsertion (CPE) in rice is an important determinant of yield and a desirable trait in breeding. However, the genetic basis of CPE in rice still remains to be completely characterized. An ethyl methane sulfonate (EMS) mutant line of an elite cultivar Samba Mahsuri (BPT 5204), displaying stable and consistent CPE, was identified and named as CPE-110. MutMap and RNA-seq were deployed for unraveling the genomic regions, genes, and markers associated with CPE. Two major genomic intervals, on chromosome 8 (25668481-25750456) and on chromosome 11 (20147154-20190400), were identified to be linked to CPE through MutMap. A non-synonymous SNP (G/A; Chr8:25683828) in the gene LOC_Os08g40570 encoding pyridoxamine 5'-phosphate oxidase with the SNP index 1 was converted to Kompetitive allele-specific PCR (KASP) marker. This SNP (KASP 8-1) exhibited significant association with CPE and further validated through assay in the F2 mapping population, released varieties and CPE exhibiting BPT 5204 mutant lines. RNA-seq of the flag leaves at the booting stage, 1100 genes were upregulated and 1305 downregulated differentially in CPE-110 and BPT 5204. Metabolic pathway analysis indicated an enrichment of genes involved in photosynthesis, glyoxylate, dicarboxylate, porphyrin, pyruvate, chlorophyll, carotenoid, and carbon metabolism. Further molecular and functional studies of the candidate genes could reveal the mechanistic aspects of CPE. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-023-01412-1.
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Many NP-hard combinatorial optimization (CO) problems can be cast as a quadratic unconstrained binary optimization model, which maps naturally to an Ising model. The final spin configuration in the Ising model can adiabatically arrive at a solution to a Hamiltonian, given a known set of interactions between spins. We enhance two photonic Ising machines (PIMs) and compare their performance against classical (Gurobi) and quantum (D-Wave) solvers. The temporal multiplexed coherent Ising machine (TMCIM) uses the bistable response of an electro-optic modulator to mimic the spin up and down states. We compare TMCIM performance on Max-cut problems. A spatial photonic Ising machine (SPIM) convolves the wavefront of a coherent laser beam with the pixel distribution of a spatial light modulator to adiabatically achieve a minimum energy configuration, and solve a number partitioning problem (NPP). Our computational results on Max-cut indicate that classical solvers are still a better choice, while our NPP results show that SPIM is better as the problem size increases. In both cases, connectivity in Ising hardware is crucial for performance. Our results also highlight the importance of better understanding which CO problems are most likely to benefit from which type of PIM. This article is part of the theme issue 'Quantum annealing and computation: challenges and perspectives'.
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Xanthomonas oryzae pv. oryzae (Xoo) is a major rice pathogen, and its genome harbors extensive inter-strain and inter-lineage variations. The emergence of highly virulent pathotypes of Xoo that can overcome major resistance (R) genes deployed in rice breeding programs is a grave threat to rice cultivation. The present study reports on a long-read Oxford nanopore-based complete genomic investigation of Xoo isolates from 11 pathotypes that are reported based on their reaction toward 10 R genes. The investigation revealed remarkable variation in the genome structure in the strains belonging to different pathotypes. Furthermore, transcription activator-like effector (TALE) proteins secreted by the type III secretion system display marked variation in content, genomic location, classes, and DNA-binding domain. We also found the association of tal genes in the vicinity of regions with genome structural variations. Furthermore, in silico analysis of the genome-wide rice targets of TALEs allowed us to understand the emergence of pathotypes compatible with major R genes. Long-read, cost-effective sequencing technologies such as nanopore can be a game changer in the surveillance of major and emerging pathotypes. The resource and findings will be invaluable in the management of Xoo and in appropriate deployment of R genes in rice breeding programs.
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Oryza , Xanthomonas , Efectores Tipo Activadores de la Transcripción/genética , Efectores Tipo Activadores de la Transcripción/metabolismo , Enfermedades de las Plantas/genética , Fitomejoramiento , Xanthomonas/genética , Oryza/genéticaRESUMEN
Leprosy type 1 reaction (T1R) is a cell-mediated inflammatory reaction which involves skin and peripheral nerves in leprosy. Lesions with T1R have higher production of IL-17 cytokine from CD4+ T cells along with lower TGF-ß producing FOXP3+ CD4+ Tregs. IL-21 is an important cytokine that promotes the development and stability of Th17 cells in an autocrine manner. It can play an important role in the pathogenesis of T1R in leprosy. However, the mechanism by which IL-21 influences the pathogenic progress of leprosy T1R remains poorly understood. In the present study, we evaluated the expression of IL-21 cytokine in skin lesions of both non-reactional (NR) and T1R via immuno-histochemistry and quantitative PCR (qPCR). Further, expression of various genes (IL-17A, IL-17F, TGF-ß, FOXP3, RORC and IL-21) was also measured by qPCR in cultured cells. We also analyzed the secretion of various cytokines such as of IL-21, IL-17A/F and TGF-ß in the culture supernatants by ELISA. In addition, differentiation of Th17 and Treg cells were studied in PBMC cultures after stimulation with Mycobacterium leprae sonicated antigens and rIL-21 for 48 hrs and the phenotypes of Th17 and Tregs were determined by flowcytometric analysis. Our results clearly indicate that IL-21+T cells were significantly higher in both peripheral blood and skin lesions of T1R as compared to NR patients. Moreover, we observed that recombinant IL-21 cytokine inhibited TGF-ß producing Treg cells differentiation along with up-regulating Th17 cells under in-vitro conditions. The gene expression of IL-21 was significantly negatively correlated with Treg and positively correlated with Th17 cell markers in T1R patients. Our results suggested that IL-21 promotes T1R mediated inflammation via modulating the balance of Th17 and Treg cell populations.
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Hipersensibilidad , Lepra , Citocinas , Factores de Transcripción Forkhead , Humanos , Inflamación , Interleucina-17/metabolismo , Interleucinas , Leucocitos Mononucleares/metabolismo , Linfocitos T Reguladores , Células Th17 , Factor de Crecimiento Transformador beta/metabolismoRESUMEN
Exoribonuclease R (RNase R) is a 3' hydrolytic exoribonuclease that can degrade structured RNA. Mutation in RNase R affects virulence of certain human pathogenic bacteria. The aim of this study was to determine whether RNase R is necessary for virulence of the phytopathogen that causes bacterial blight in rice, Xanthomonas oryzae pv. oryzae (Xoo). In silico analysis has indicated that RNase R is highly conserved among various xanthomonads. Amino acid sequence alignment of Xoo RNase R with RNase R from various taxa indicated that Xoo RNase R clustered with RNase R of order Xanthomonadales. To study its role in virulence, we generated a gene disruption mutant of Xoo RNase R. The Xoo rnr- mutant is moderately virulence deficient, and the complementing strain (rnr-/pHM1::rnr) rescued the virulence deficiency of the mutant. We investigated swimming and swarming motilities in both nutrient-deficient minimal media and nutrient-optimal media. We observed that RNase R mutation has adversely affected the swimming and swarming motilities of Xoo in optimal media. However, in nutrient-deficient media only swimming motility was noticeably affected. Growth curves in optimal media at suboptimal temperature (15°C cold stress) indicate that the Xoo rnr- mutant grows more slowly than the Xoo wild type and complementing strain (rnr-/pHM1::rnr). Given these findings, we report for the first time that RNase R function is necessary for complete virulence of Xoo in rice. It is also important for motility of Xoo in media and for growth of Xoo at suboptimal temperature.
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Oryza , Xanthomonas , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Exorribonucleasas/metabolismo , Oryza/microbiología , Enfermedades de las Plantas/microbiología , VirulenciaRESUMEN
Xanthomonas is a major group of pathogenic bacteria infecting staple food crops like rice. Increasingly it is being recognized that non-pathogenic Xanthomonas (NPX) are also important members of a healthy plant microbiome. However, the vast majority of the species described in this genus are of pathogenic nature, and only a few NPX species have been reported till now. Genomic and taxonogenomic analysis of NPX is needed for the management of this important group of bacteria. In this study, two yellow-pigmented bacterial isolates were obtained from healthy rice seeds in Punjab, India. The isolates designated PPL560T and PPL568 were identified as members of the genus Xanthomonas based on biochemical tests and 16S rRNA gene sequence analysis retrieved from the whole-genome sequences. Isolates formed a distinct monophyletic lineage with Xanthomonas sontii and Xanthomonas sacchari as the closest relatives in the phylogenetic tree based on core gene content shared by the representative species of the genus Xanthomonas. Pairwise ortho Average Nucleotide Identity and digital DNA-DNA hybridization values calculated against other species of Xanthomonas were below their respective cut-offs. In planta studies revealed that PPL560T and PPL568 are non-pathogenic to rice plants upon leaf clip inoculation. The absence of type III secretion system-related genes and effectors further supported their non-pathogenic status. Herein, we propose Xanthomonas indica sp. nov. as novel species of the genus Xanthomonas with PPL560T = MTCC 13185 = CFBP 9039 = ICMP 24394 as its type strain and PPL568 as another constituent member.
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Oryza , Xanthomonas , ADN Bacteriano/química , ADN Bacteriano/genética , Oryza/microbiología , Filogenia , ARN Ribosómico 16S/genética , Semillas , Xanthomonas/genéticaRESUMEN
OBJECTIVES: Patients with Clostridioides difficile infection (CDI) who receive treatment at outpatient infusion centers (OICs) pose a risk for spore transmission. We investigated C. difficile contamination in the environment of CDI and non-CDI patients and evaluated the effectiveness of standard cleaning. METHODS: This is a multicenter, non-conventional study including 8 OICs between October 2019 and December 2020. Samples were collected at baseline, after infusion, and after cleaning CDI and non-CDI areas. Cleaning was performed using hypochlorite and non-hypochlorite products for CDI and non-CDI, respectively. Samples were cultured for toxigenic C. difficile and strain-typed via fluorescent PCR ribotyping and whole-genome sequencing. RESULTS: The overall C. difficile contamination rate was 7.9% (156/1969) with 8.1% in patient and 5.6% in non-patient care areas, respectively. For CDI areas, contamination rates were 5.9% at baseline, 15.0% after infusion, and significantly reduced to 6.2% after cleaning (P = 0.004). For non-CDI areas, contamination was similar at baseline (9.5%), after infusion (7.6%), and after cleaning (4.3%). The difference in C. difficile-positive samples after infusion was significant for CDI vs. non-CDI (15.0% vs. 7.6%, P = 0.004). Overall contamination was 11.5% for floors, 7.9% for infusion chairs, and 3.8% for equipment (P = 0.001). The most frequent ribotypes were F014-020 (42.6%), F106 (15.6%), F255 (6.1%), F001 (5.2%) and F027 (3.5%). Cleaning resulted in elimination of F106, F255, F001, F027 and partial reduction of F014-020. CONCLUSIONS: Environmental C. difficile contamination was increased after CDI infusions and significantly reduced after cleaning with a hypochlorite solution, reducing the potential risk of spore transmission to others.
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Clostridioides difficile , Infecciones por Clostridium , Infección Hospitalaria , Humanos , Pacientes Ambulatorios , Infección Hospitalaria/prevención & control , Esporas Bacterianas , Infecciones por Clostridium/prevención & control , RibotipificaciónRESUMEN
Xanthomonas oryzae pv. oryzae uses several type III secretion system (T3SS) secreted effectors, namely XopN, XopQ, XopX and XopZ, to suppress rice immune responses that are induced following treatment with cell wall degrading enzymes. Here we show that a T3SS secreted effector XopX interacts with two of the eight rice 14-3-3 proteins. Mutants of XopX that are defective in 14-3-3 binding are also defective in suppression of immune responses, suggesting that interaction with 14-3-3 proteins is required for suppression of host innate immunity. However, Agrobacterium-mediated delivery of both XopQ and XopX into rice cells results in induction of rice immune responses. These immune responses are not observed when either protein is individually delivered into rice cells. XopQ-XopX-induced rice immune responses are not observed with a XopX mutant that is defective in 14-3-3 binding. Yeast two-hybrid, bimolecular fluorescence complementation and co-immunoprecipitation assays indicate that XopQ and XopX interact with each other. A screen for Xanthomonas effectors that can suppress XopQ-XopX-induced rice immune responses led to the identification of five effectors, namely XopU, XopV, XopP, XopG and AvrBs2, that could individually suppress these immune responses. These results suggest a complex interplay of Xanthomonas T3SS effectors in suppression of both pathogen-triggered immunity and effector-triggered immunity to promote virulence on rice.
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Proteínas Bacterianas/metabolismo , Interacciones Huésped-Patógeno/inmunología , Oryza/inmunología , Oryza/microbiología , Xanthomonas/patogenicidad , Proteínas 14-3-3/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/inmunología , Sitios de Unión , Núcleo Celular/metabolismo , Mutación , Fosforilación , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/microbiología , Inmunidad de la Planta , Proteínas de Plantas/inmunología , Proteínas de Plantas/metabolismo , Serina/genética , Xanthomonas/metabolismoRESUMEN
The countries in the Indian subcontinent have reported a dramatic decline in visceral leishmaniasis (VL) cases. However, the presence of the parasite reservoir in the form of post-kala-azar dermal leishmaniasis (PKDL), a dermal sequel of VL, is a hurdle in attaining VL elimination. Presently employed clinical specimens for the diagnosis of PKDL include skin biopsy specimens and slit skin smears. In this study, the use of blood as a clinical specimen was investigated in different manifestations of PKDL in India. This is a bicentric study (National Institute of Pathology, Indian Council of Medical Research [ICMR], New Delhi, and Institute of Medical Sciences [IMS], Banaras Hindu University, Varanasi), with 215 participants (120 PKDL patients and 95 controls). Highly sensitive quantitative real-time PCR (Q-PCR) and field-deployable loop-mediated isothermal amplification (LAMP) were employed using blood samples for diagnosis. Promising sensitivities of 77.50% (95% confidence interval [CI], 69.24 to 84.05%) for Q-PCR and 70.83% (95% CI, 62.16 to 78.22%) for LAMP were obtained for the diagnosis of PKDL. Further, enhanced sensitivities of 83.33% (95% CI, 71.28 to 90.98%) and 77.78% (95% CI, 65.06 to 86.80%) for Q-PCR and LAMP, respectively, were recorded for the detection of macular cases. The study revealed an inverse correlation between the parasite load estimated in slit and blood samples, thereby favoring the use of blood for the diagnosis of the macular variant, which may be missed due to scant parasite loads in the slit. This study is the first to propose the promising potential of blood as a clinical specimen for accurate diagnosis of PKDL, which would aid in fast-tracking VL elimination.
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Leishmania donovani , Leishmaniasis Cutánea , Leishmaniasis Visceral , Humanos , India , Leishmania donovani/genética , Leishmaniasis Cutánea/diagnóstico , Leishmaniasis Visceral/diagnóstico , Técnicas de Diagnóstico Molecular , Técnicas de Amplificación de Ácido Nucleico , Reacción en Cadena en Tiempo Real de la PolimerasaRESUMEN
Plant pathogens secrete cell wall-degrading enzymes that degrade various components of the plant cell wall. Plants sense this cell wall damage as a mark of infection and induce immune responses. However, the plant functions that are involved in the elaboration of cell wall damage-induced immune responses remain poorly understood. Transcriptome analysis revealed that a rice (Oryza sativa) receptor-like kinase, WALL-ASSOCIATED KINASE-LIKE21 (OsWAKL21.2), is up-regulated following treatment with either Xanthomonas oryzae pv oryzae (a bacterial pathogen) or lipaseA/esterase (LipA; a cell wall-degrading enzyme of X. oryzae pv oryzae). Overexpression of OsWAKL21.2 in rice induces immune responses similar to those activated by LipA treatment. Down-regulation of OsWAKL21.2 attenuates LipA-mediated immune responses. Heterologous expression of OsWAKL21.2 in Arabidopsis (Arabidopsis thaliana) also activates plant immune responses. OsWAKL21.2 is a dual-activity kinase that has in vitro kinase and guanylate cyclase activities. Interestingly, kinase activity of OsWAKL21.2 is necessary to activate rice immune responses, whereas in Arabidopsis, OsWAKL21.2 guanylate cyclase activity activates these responses. Our study reveals a rice receptor kinase that activates immune responses in two different species via two different mechanisms.
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Oryza/enzimología , Oryza/inmunología , Inmunidad de la Planta , Proteínas de Plantas/metabolismo , Proteínas Quinasas/metabolismo , Arabidopsis/genética , Ciclopentanos/metabolismo , Regulación hacia Abajo/genética , Regulación de la Expresión Génica de las Plantas , Lipasa/metabolismo , Oryza/microbiología , Oxilipinas/metabolismo , Hojas de la Planta/metabolismo , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente , Ácido Salicílico/metabolismo , Xanthomonas/fisiologíaRESUMEN
ABSTRACT: Tuberculosis in all forms, that is, pulmonary (PTB) or extrapulmonary (EPTB), is a universal health problem. Cutaneous tuberculosis (CTb) remains one of the least studied and often under-reported variants of EPTB because of its wide and protean clinical presentation. The diagnosis of CTb remains challenging because of lack of sensitive and specific investigations for its diagnosis. The sensitivity of some of the traditional tests is low because of low concentration of mycobacteria in paucibacillary lesions. Besides it is difficult to distinguish between M. tuberculosis (MTb) and other mycobacterial species in skin biopsies morphologically. Molecular methods may target either MTb DNA or RNA, and serve as promising tools in the diagnosis of various forms of CTb, with high sensitivity and rapidity. This review is focused on diagnostic challenges of CTb and to discuss various methods and newer technologies for diagnosing CTb. This will help the dermatologists and dermatopathologists to elucidate and accurately diagnose CTb from other infectious granulomatous dermatitis for appropriate timely treatment of the patient.
Asunto(s)
Tuberculosis Cutánea/diagnóstico , HumanosRESUMEN
BACKGROUND: No satisfactory canonical treatment is available for post-kala-azar dermal leishmaniasis (PKDL), clinical sequela of visceral leishmaniasis. Confined treatment options and substantial increase in relapse rate after miltefosine (MIL) treatment warrant the need to adapt resilient combination therapies. In this study, we assessed the safety and efficacy of combination therapy using liposomal amphotericin B (LAmB) and MIL for treating PKDL. METHODS: Thirty-two PKDL patients, confirmed by microscopy or quantitative polymerase chain reaction (qPCR), were included in the study. An equal number of cases (n = 16) were put on MIL monotherapy (100 mg/day for 90 days) or MIL and LAmB combination for 45 days (3 injections of LAmB, 5 mg/kg body weight, and 100 mg/day MIL). Parasite load in slit aspirate was monitored using qPCR. RESULTS: Patients treated with combination therapy demonstrated a rapid decline in parasite load and achieved 100% cure, with no reports of relapse. Those treated with MIL monotherapy attained clinical cure with a gradual decrease in parasite load; however, 25% relapsed within 18 months of follow-up. CONCLUSIONS: Liposomal amphotericin B and MIL combination for treating PKDL is efficacious and safe, with high tolerability. Furthermore, this study established the utility of minimally invasive slit aspirate method for monitoring of parasite load and assessment of cure in PKDL.