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Lesion mimic mutants (LMMs) are plants that spontaneously form lesions without pathogen infection or external stimulus and exhibit resistance to pathogens. Here, a rice LMM was created by ethyl methane sulfonate mutagenesis, named as hpil (hydrogen peroxide induced lesion). Diaminobenzidine and trypan blue staining showed that large amounts of H2O2 were produced and cell death was occurred at and around the parts of lesion mimic in the rice leaves. The phenotype of hpil is controlled by a single recessive gene, localized at a 2 Mb interval on chromosome 2. The data suggested that hpil is a novel LMM with enhanced bacterial and fungal disease resistance, and multiple pathogenesis-related proteins (PRs) were up-regulated. The proteomes of leaves at three positions (different degrees of lesion mimic severity) were characterized in hpil compared with its wild type plant. Differentially expressed proteins were detected by two dimensional difference gel electrophoresis and 274 proteins were identified by MALDI TOF/TOF™. These proteins were related to metabolic process, cellular process and response to stimulus, with mostly down-regulated in hpil leaves. Many of these proteins were related to the Calvin cycle, photosynthetic electron transport chain, glycolysis/gluconeogenesis and phosphonates pathways. Some resistance-related proteins including 14-3-3 proteins, OsPR10 and antioxidases such as peroxidase, superoxide dismutase and ascorbate peroxidase were up-regulated in leaves with lesion mimic. These results provide the foundation for cloning of the target gene and shed light on the mechanism involved in autoimmunity of rice.

Oryza meyeriana is a wild species of rice with high resistance to Xanthomonas oryzae pv. oryzae (Xoo), but the detailed resistance mechanism is unclear. Ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) activase (RCA) is an important enzyme that regulates photosynthesis by activating Rubisco. We have previously reported that Xoo infection induced the relocation of RCA from the chloroplast stroma to the thylakoid membrane in O. meyeriana, but the underlying regulating mechanism and physiological significance of this association remains unknown. In this study, "H2O2 burst" with rapid and large increase in the amount of H2O2 was found to be induced by Xoo invasion in the leaves of O.meyeriana. 3, 3-diaminobenzidine (DAB) and oxidative 2, 7-Dichlorodi-hydrofluorescein diacetate (H2DCFDA) staining experiments both showed that H2O2 was generated in the chloroplast of O.meyeriana, and that this H2O2 generation as well as Xoo resistance of the wild rice were dramatically dependent on light. H2O2, methyl viologen with light, and the xanthine-xanthine oxidase system all induced RCA to associate with the thylakoid membrane in vitro, which showed that H2O2 could induce the relocation of RCA. In vitro experiments also showed that H2O2 induced changes in both the RCA and thylakoid membrane that were required for them to associate and that this association only occurred in O. meyeriana and not in the susceptible cultivated rice. These results suggest that the association of RCA with the thylakoid membrane helps to protect the thylakoid membrane against oxidative damage from H2O2. Therefore, in addition to its universal function of activating Rubisco, RCA appears to play a novel role in the resistance of O. meyeriana to Xoo. [ABSTRACT FROM AUTHOR]

Background: Neutrophil extracellular traps (NETs) have been shown to play a pivotal role in promoting metastasis and immune escape in hepatocellular carcinoma (HCC). Therefore, noninvasive tests to detect the formation of NETs in tumors can have significant implications for the treatment and prognoses of patients. Here, we sought to develop and validate a computed tomography (CT)-based radiomics model to predict the gene expression profiles that regulate the formation of NETs in HCC., Methods: This study included 1133 HCC patients from five retrospective cohorts. Based on the mRNA expression levels of 69 biomarkers correlated with NET formation, a 6-gene score (NETs score, NETS) was constructed in cohort 1 from TCIA database (n=52) and validated in cohort 2 (n=232) from ICGC database and cohort 3 (n=365) from TCGA database. And then based on the radiomics features of CT images, a radiomics signature (RNETS) was developed in cohort 1 to predict NETS status (high- or low-NETS). We further employed two cohorts from Nanfang Hospital (Guangzhou, China) to evaluate the predictive power of RNETS in predicting prognosis in cohort 4 (n=347) and the responses to PD-1 inhibitor of HCC patients in cohort 5 (n=137)., Results: For NETS, in cohort 1, the area under the curve (AUC) values predicting 1, 2, and 3-year overall survival (OS) were 0.836, 0.879, and 0.902, respectively. The low-NETS was associated with better survival and higher levels of immune cell infiltration. The RNETS yielded an AUC value of 0.853 in distinguishing between high-NETS or low-NETS and patients with low-RNETS were associated with significantly longer survival time in cohort 1 ( P <0.001). Notably, the RNETS was competent in predicting disease-free survival (DFS) and OS in cohort 4 ( P <0.001). In cohort 5, the RNETS was found to be an independent risk factor for progression-free survival (PFS) ( P <0.001). In addition, the objective response rate of HCC patients treated with PD-1 inhibitor was significantly higher in the low-RNETS group (27.8%) than in the high-RNETS group (10.8%)., Conclusions: This study revealed that RNETS as a radiomics biomarker could effectively predict prognosis and immunotherapy response in HCC patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Xin, Lai, Zhou, He, Song, Liao, Sun, Li, Zhang, Liang, Bai, Zhang and Zhou.)

Oryza meyeriana is a wild species of rice with high resistance to Xanthomonas oryzae pv. oryzae (Xoo), but the detailed resistance mechanism is unclear. Ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) activase (RCA) is an important enzyme that regulates photosynthesis by activating Rubisco. We have previously reported that Xoo infection induced the relocation of RCA from the chloroplast stroma to the thylakoid membrane in O. meyeriana, but the underlying regulating mechanism and physiological significance of this association remains unknown. In this study, "H 2 O 2 burst" with rapid and large increase in the amount of H 2 O 2 was found to be induced by Xoo invasion in the leaves of O. meyeriana. 3, 3-diaminobenzidine (DAB) and oxidative 2, 7-Dichlorodi-hydrofluorescein diacetate (H 2 DCFDA) staining experiments both showed that H 2 O 2 was generated in the chloroplast of O. meyeriana, and that this H 2 O 2 generation as well as Xoo resistance of the wild rice were dramatically dependent on light. H 2 O 2 , methyl viologen with light, and the xanthine-xanthine oxidase system all induced RCA to associate with the thylakoid membrane in vitro, which showed that H 2 O 2 could induce the relocation of RCA. In vitro experiments also showed that H 2 O 2 induced changes in both the RCA and thylakoid membrane that were required for them to associate and that this association only occurred in O. meyeriana and not in the susceptible cultivated rice. These results suggest that the association of RCA with the thylakoid membrane helps to protect the thylakoid membrane against oxidative damage from H 2 O 2 . Therefore, in addition to its universal function of activating Rubisco, RCA appears to play a novel role in the resistance of O. meyeriana to Xoo., Competing Interests: The authors declare no conflict of interest.

Objective: To determine whether the transfusion-transmitted virus (TTV) is hepatotropic., Methods: Total DNA was extracted from various tissues of 5 experimentally infected Rhesus monkeys during the viremic period. A dot hybridization was done with viral double stranded DNA probes or single antisense probes., Results: The double-stranded probe was hybridized with DNA from the liver, bone marrow, spleen,stomach, small intestine and colon. The single-stranded antisense probe was hybridized with DNA from the liver, small intestine and bone marrow of all 5 monkeys, but not with that from other tissues., Conclusions: As the viral genome was of negative polarity, the plus-stranded fragment identified in our study might be a replicative intermediate, and was only demonstrated in the liver, small intestine, and bone marrow by dot blot hybridization with single-stranded antisense probes. It is suggested that the TTV replicates in the liver, bone marrow and small intestine, and TTV might be hepatotropic.