Fungal effector SIB1 of Colletotrichum orbiculare has unique structural features and can suppress plant immunity in Nicotiana benthamiana

Fungal plant pathogens secrete virulence-related proteins, called effectors, to establish host infection, however, the details are not fully understood yet. Functional screening of effector candidates using Agrobacterium-mediated transient expression assay in Nicotiana benthamiana identified two virulence-related effectors, named SIB1 and SIB2 (Suppression of Immunity in N. benthamiana), of an anthracnose fungus Colletotrichum orbiculare, which infects both cucurbits and N. benthamiana. The Agrobacterium-mediated transient expression of SIB1 or SIB2 increased the susceptibility of N. benthamiana to C. orbiculare, which suggested these effectors can suppress immune responses in N. benthamiana. The presence of SIB1 and SIB2 homologs was found to be limited to the genus Colletotrichum. SIB1 suppressed both (i) the generation of reactive oxygen species (ROS) triggered by two different pathogen-associated molecular patterns (PAMPs), chitin and flg22, and (ii) the cell death response triggered by the Phytophthora infestans INF1 elicitin in N. benthamiana. We determined the NMR-based structure of SIB1 to obtain its structural insights. The three-dimensional structure of SIB1 comprises five β-strands, each containing three disulfide bonds. The overall conformation was found to be a cylindrical shape, such as the well-known antiparallel β-barrel structure. However, the β-strands were found to display a unique topology, one pair of these β-strands formed a parallel β-sheet. These results suggest that the effector SIB1 present in Colletotrichum fungi has unique structural features and can suppress PAMP-triggered immunity (PTI) in N. benthamiana

Lithium ion conductive behavior of TiO_2 nanotube/ionic liquid matrices

A series of TiO_2 nanotube (TNT)/ionic liquid matrices were prepared, and their lithium ion conductive properties were studied. SEM images implied that ionic liquid was dispersed on the whole surface of TNT. Addition of TNT to ionic liquid (1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide (BMImTFSA)) resulted in significant increase of ionic conductivity. Furthermore, lithium transference number was also largely enhanced due to the interaction of anion with TNT. Vogel-Fulcher-Tammann parameter showed higher carrier ion number for TNT/BMImTFSA in comparison with BMImTFSA

Anormalidad de la unión al ADN de Oct-1 en las células T de pacientes con síndrome de Sjogren

Primary Sjögren's syndrome (SS) is an autoimmune rheumatic disease characterized by T cell hypoactivity. To understand the diminished T cell response to activation signals, we measured nucleoprotein DNA?binding activities regulating gene expression during T cell activation using the electrophoretic mobility shift assay. Peripheral blood lymphocytes from 9/19 SS patients were found to be defective in their ability to bind an octomer sequence (Oct?1). This Oct?1?binding phenotype remained stable in culture for up to 3 days prior to activation. This abnormality was not seen in resting T cells nor T cells from patients with systemic lupus erythematosus, rheumatoid arthritis (RA), or SS accompanied by RA. The SS Oct?1 DNA?binding abnormality correlated significantly with an inability of cells to exit the G0/G1 cell cycle phase when stimulated in vitro . Importantly, nucleoprotein extracts showing decreased DNA?binding activity had normal amounts of Oct?1 proteins as determined by immunoprecipitation, implying a functional defect in the Oct?1 protein. Moreover, defective DNA binding was corrected by treatment with acid phosphatase

Apoptosis linfocitaria y expresión génica asociada a la apoptosis en el síndrome de Sjögren

Objective . To study the mechanism and regulation of apoptosis in peripheral blood T and B lymphocytes from patients with Sjögren's syndrome (SS). Methods . The mode of in vitro lymphocyte death in the peripheral blood of patients with SS was determined by fluorescence microscopic analysis, terminal deoxynucleotidyl transferase assay, and DNA fragmentation analysis. Apoptotic cell death of T and B cells was determined at 48 hours of culture by fluorescence?activated cell sorter analysis of propidium iodidestained cells. Messenger RNA (mRNA) expression of bcl?2, bcl?x, bax , and c?myc in T and B cells was determined by enzyme?linked immunosorbent assaypolymerase chain reaction (ELISA?PCR). Expression of bcl?xL and bcl?xS was determined by Southern blot analysis of PCR products. Gene expression was calculated as the ratio of each gene message to the message of the GAPDH gene. Bcl?2 protein levels in SS T cells were determined by ELISA. Results . SS T cells showed increased in vitro apoptosis compared with normal T cells (mean ± SD 12.3 ± 4.5% versus 7.3 ± 2.0%; P < 0.01). Freshly isolated SS T cells showed increased expression of bcl?2 mRNA compared with normal controls (mean ± SD 1.50 ± 0.65 versus 0.88 ± 0.23; P < 0.05). There was no significant difference in levels of bax or c?myc mRNA in T cells and B cells between SS patients and normal controls. When SS T lymphocytes were cultured in vitro for 72 hours, Bcl?2 protein levels decreased with time. Conclusion . SS T cells showed accelerated apoptosis in vitro. Freshly isolated SS T cells had increased expression of bcl?2. An increase in death?promoter signals and decrease in death?suppressor signals in vitro may have been responsible, in part, for the apoptosis in SS T lymphocytes

Apoptosis linfocitaria y expresión génica asociada a la apoptosis en el síndrome de Sjögren

Objective . To study the mechanism and regulation of apoptosis in peripheral blood T and B lymphocytes from patients with Sjögren's syndrome (SS). Methods . The mode of in vitro lymphocyte death in the peripheral blood of patients with SS was determined by fluorescence microscopic analysis, terminal deoxynucleotidyl transferase assay, and DNA fragmentation analysis. Apoptotic cell death of T and B cells was determined at 48 hours of culture by fluorescence?activated cell sorter analysis of propidium iodidestained cells. Messenger RNA (mRNA) expression of bcl?2, bcl?x, bax , and c?myc in T and B cells was determined by enzyme?linked immunosorbent assaypolymerase chain reaction (ELISA?PCR). Expression of bcl?xL and bcl?xS was determined by Southern blot analysis of PCR products. Gene expression was calculated as the ratio of each gene message to the message of the GAPDH gene. Bcl?2 protein levels in SS T cells were determined by ELISA. Results . SS T cells showed increased in vitro apoptosis compared with normal T cells (mean ± SD 12.3 ± 4.5% versus 7.3 ± 2.0%; P < 0.01). Freshly isolated SS T cells showed increased expression of bcl?2 mRNA compared with normal controls (mean ± SD 1.50 ± 0.65 versus 0.88 ± 0.23; P < 0.05). There was no significant difference in levels of bax or c?myc mRNA in T cells and B cells between SS patients and normal controls. When SS T lymphocytes were cultured in vitro for 72 hours, Bcl?2 protein levels decreased with time. Conclusion . SS T cells showed accelerated apoptosis in vitro. Freshly isolated SS T cells had increased expression of bcl?2. An increase in death?promoter signals and decrease in death?suppressor signals in vitro may have been responsible, in part, for the apoptosis in SS T lymphocytes