Receptor-like cytoplasmic kinases of different subfamilies differentially regulate SOBIR1/BAK1-mediated immune responses in Nicotiana benthamiana.

Cell-surface receptors form the front line of plant immunity. The leucine-rich repeat (LRR)-receptor-like kinases SOBIR1 and BAK1 are required for the functionality of the tomato LRR-receptor-like protein Cf-4, which detects the secreted effector Avr4 of the pathogenic fungus Fulvia fulva. Here, we show that the kinase domains of SOBIR1 and BAK1 directly phosphorylate each other and that residues Thr522 and Tyr469 of the kinase domain of Nicotiana benthamiana SOBIR1 are required for its kinase activity and for interacting with signalling partners, respectively. By knocking out multiple genes belonging to different receptor-like cytoplasmic kinase (RLCK)-VII subfamilies in N. benthamiana:Cf-4, we show that members of RLCK-VII-6, -7, and -8 differentially regulate the Avr4/Cf-4-triggered biphasic burst of reactive oxygen species. In addition, members of RLCK-VII-7 play an essential role in resistance against the oomycete pathogen Phytophthora palmivora. Our study provides molecular evidence for the specific roles of RLCKs downstream of SOBIR1/BAK1-containing immune complexes.

Immune signaling: receptor-like proteins make the difference.

To resist biotic attacks, plants have evolved a sophisticated, receptor-based immune system. Cell-surface immune receptors, which are either receptor-like kinases (RLKs) or receptor-like proteins (RLPs), form the front line of the plant defense machinery. RLPs lack a cytoplasmic kinase domain for downstream immune signaling, and leucine-rich repeat (LRR)-containing RLPs constitutively associate with the RLK SOBIR1. The RLP/SOBIR1 complex was proposed to be the bimolecular equivalent of genuine RLKs. However, it appears that the molecular mechanisms by which RLP/SOBIR1 complexes and RLKs mount immunity show some striking differences. Here, we summarize the differences between RLP/SOBIR1 and RLK signaling, focusing on the way these receptors recruit the BAK1 co-receptor and elaborating on the negative crosstalk taking place between the two signaling networks.

Exposure to endocrine-disrupting plasticisers and lung function in children and adolescents: A systematic review and meta-analysis.

Exposure to endocrine-disrupting plasticisers (EDPs), such as phthalates and bisphenols, has been associated with reduced lung function in children and adolescents. However, the existing literature yields conflicting results. This systematic review and meta-analysis aimed to assess the epidemiologic evidence investigating the association between EDP exposure and lung function in children and adolescents. A comprehensive search of five databases identified 25 relevant studies. We employed a random-effects meta-analysis on spirometry measures. The effect size of interest was the change in lung function in standard deviation (SD) units resulting from a two-fold increase in exposure levels. We found that certain phthalates marginally reduced lung function in children. Forced expiratory volume in 1 s (FEV1) was reduced by a two-fold increase in mono-benzyl phthalate (MBzP) (ß = -0.025 SD, 95%CI: 0.042, -0.008), mono-ethyl-oxo-hexyl phthalate (MEOHP) (ß = -0.035 SD, 95%CI: 0.057, -0.014) and mono-carboxy-nonyl phthalate (MCNP) (ß = -0.024 SD, 95%CI: 0.05, -0.003). Forced vital capacity (FVC) was decreased by a two-fold increase in MBzP (ß = -0.022 SD, 95%CI: 0.036, -0.008) and MEOHP (ß = -0.035 SD, 95%CI: 0.057, -0.014) levels. A two-fold increase in MCNP levels was associated with lower FEV1/FVC (ß = -0.023 SD, 95%CI: 0.045, -0.001). Furthermore, a two-fold increase in MEOHP levels reduced forced mid-expiratory flow (FEF25-75) (ß = -0.030 SD, 95%CI: 0.055, -0.005) and peak expiratory flow (PEF) (ß = -0.056 SD, 95%CI: 0.098, -0.014). Notably, associations were more pronounced in males. Given the potential for reverse causation bias, the association between childhood exposure to EDPs and lung function remains uncertain. Overall, our meta-analysis showed small reductions in lung function with higher phthalate exposure. However, future studies are warranted in younger age groups.

Household characteristics associated with environmentally persistent free radicals in house dust in two Australian locations.

The association between air pollution and adverse health outcomes has been extensively studied, and while oxidative stress in likely to be involved, the underlying mechanism(s) remain unclear. Recent studies propose environmentally persistent free radicals (EPFRs) as the missing connection between air pollution and detrimental health impacts. However, the indoor environment is rarely considered in EPFR research. We measured EPFRs in household dust from two locations in Australia and investigated household characteristics associated with EPFRs. Random forest models were built to identify important household characteristics through variable importance plots and the associations were analysed using Spearman's rho test. We found that age of house, type of garage, house outer wall material, heating method used in home, frequency of extractor fan use when cooking, traffic related air pollution, frequency of cleaning and major house renovation were important household characteristics associated with EPFRs in Australian homes. The direction of association between household characteristics and EPFRs differ between the locations. Hence, further research is warranted to determine the generalisability of our results.

[Thoughts on the watch and wait strategy of patients with rectal cancer after neoadjuvant therapy].

In 2004, Habr-Gama reported a new group of rectal cancer patients achieving clinical complete response (cCR) after neoadjuvant chemoradiotherapy, who were able to get a satisfactory curative effect after a non-operative watch and wait (W&W) strategy. Since then, W&W has attracted more and more public attention. Although results of accumulating clinical studies have shown that W&W strategy is feasible for treating part of rectal cancer patients, there is still a lack of evidence-based medical evidence. Therefore, the feasibility and safety of the strategy still need further investigation. The main focuses are on the optimized scheme of chemoradiotherapy, the timing and standard to evaluate a cCR, and the shortage of a more precise approach to judging and predicting cCR. Whether a salvage surgery is safe and feasible for local regeneration, the risk of increasing distant metastasis and long-term oncologic and functional outcomes of patients also remain uncertain. Based on the literature and the institute's experience, this paper will elaborate the current development status and existing problems of W&W and look forward to the application prospect and future challenges.

[Ultrasonographic assessment of diaphragm function in long-term mechanical ventilation patients].

Objective: To evaluate the condition of the diaphragm in patients with long-term mechanical ventilation using ultrasound technology and to analyze its relationship with ventilation time and muscle atrophy in order to clarify the reasons for diaphragm dysfunction in long-term mechanical ventilation patients. Methods: Patients admitted to the respiratory department at the Chinese PLA General Hospital between June 2018 and April 2019 with mechanical ventilation were included in this study. The enrolled patients were divided into a short-term mechanical ventilation group (7 days ≤ ventilation time<1 month) and a long-term mechanical ventilation group (mechanical ventilation time ≥ 1 month). The diaphragmatic excursion, inspiratory time, contraction rate, E-T index, diaphragm thickness, diaphragm thickness fraction (DTF), and tibialis anterior thickness were compared between the two groups. The correlation between ventilation time and diaphragm thickness was analyzed in all patients. Results: The mean diaphragm thickness and DTF were significantly lower in the long-term mechanical ventilation group than in the short-term mechanical ventilation group [(0.13±0.036) vs (0.17±0.05) cm and (0.22±0.045) vs (0.27±0.075)](all P<0.05). However, there was no significant difference in diaphragmatic excursion, inspiratory time, contraction rate, E-T index or tibialis anterior thickness between the two groups (all P>0.05). There was a significant linear correlation between ventilation time and diaphragm thickness (P<0.01). Tibialis anterior thickness was not significantly correlated with ventilation time (P>0.05). Conclusion: Diaphragm thickness and function were significantly reduced in patients with long-term mechanical ventilation, which was correlated with the duration of ventilation. Nutritional status was not the main factor affecting diaphragm thickness.

[Discussion of correlation between histogram analysis of quantitative diffusion weighted imaging and Gleason score of prostate cancer].

Objective: To discuss the correlation between histogram analysis of quantitative mono-exponential, bi-exponential and diffusion kurtosis models in diffusion weighted imaging and the Gleason score of prostate cancer, and evaluate the application value and diagnostic efficiency in identifying low and high grade prostate cancer. Methods: A total of 50 patients with histologically confirmed as prostate cancer were examined from May 2015 to May 2016 in the Second Affiliated Hospital of Soochow University using DWI performed at 3.0 T with an extended b-value range from 0 to 2 000 s/mm(2). Data were post-processed by whole tumor histogram analysis,the ROI was manually drown in DWI (b=1 000 s/mm(2)) step by step along the outline of cancer, and quantitative analysis were performed respectively by mono-exponential, bi-exponential and diffusion kurtosis models for quantification of apparent diffusion coefficients (ADCs), diffusivity D, pseudo-diffusivity D(*), perfusion fraction f, diffusion coefficients by non-Gaussian distribution (D(k)) and kurtosis coefficient (K).Then the histogram analysis was performed to get the mean, median, 25th percentile, 75th percentile, skewness and kurtosis. The correlation between histogram analysis results of these quantitative parameters and Gleason score of prostate cancer were evaluated by Spearman correlation coefficient. The diagnostic performance of histogram analysis results of each quantitative parameters in identifying low (Gleason score≤6) and high (Gleason score>6) grade prostate cancer was performed by comparing the area under the ROC curve and the curve values. Results: The values of ADC, D and D(k) (mean, median, 25th, 75th) were negatively correlated with Gleason score of prostate cancer (r value was -0.388--0.624, P<0.05). The values of D (skewness and kurtosis) had a certain correlation with Gleason score of prostate cancer (r value were 0.413 and 0.402, P<0.05). The histogram analysis results of D(*) and f had no statistically significant correlation with Gleason score of prostate cancer (P>0.05). The values of K (mean, median, 25th, kurtosis) were positively correlated with Gleason score of prostate cancer (r value was 0.423-0.699,P<0.05). The diagnostic efficiency of histogram analysis results of these quantitative parameter values in identifying low and high grade prostate cancer showed that the ADC (median), D (25th), D(k) (mean) and K (25th) had a larger area under the curve, and were 0.844, 0.873, 0.815, and 0.919 respectively, the differences of area under the curve between any two of these parameters above were not statistically significant (all P>0.05). Conclusions: The quantitative parameters of three diffusion models (ADC, D, D(k), K) in DWI are all related to the Gleason score of prostate cancer, but in the differential diagnosis of low and high grade prostate cancer, the diagnostic efficacy of mono-exponential model is sufficient. The more complex model such as bi-exponential and diffusion kurtosis may complement it in other ways.

Bis(3)-tacrine inhibits the sustained potassium current in cultured rat hippocampal neurons.

Bis(3)-tacrine is a dimeric AChE inhibitor derived from tacrine with a potential to treat Alzheimer's disease. It was recently been reported to act as a fast off-rate antagonist of NMDA receptors with moderate affinity. In the present study, we aimed to explore whether bis(3)-tacrine could modulate the function of native sustained potassium current in cultured rat hippocampal neurons using whole-cell patch-clamp technique. We found that bis(3)-tacrine inhibited the amplitude of sustained potassium current in a reversible and concentration-dependent manner, with a potency two orders of magnitude higher than that of tacrine. The inhibition was voltage-independent between 0 to +60 mV. The IC(50) values for bis(3)-tacrine and tacrine inhibition of sustained potassium current were 0.45+/-0.07 and 50.5+/-4.8 microM, respectively. I-V curves showed a more potent inhibition of sustained potassium current by bis(3)-tacrine (1 microM) compared to tacrine at the same concentration. Bis(3)-tacrine hyperpolarized the activation curve of the current by 11.2 mV, albeit leaving the steady-state inactivation of the current unaffected.

[Expression of LIM and SH3 protein 1 in renal clear cell carcinoma and its effects on invasion and migration of renal clear cell carcinoma 786-O cells].

Objective: To investigate the expression of LIM and SH3 protein 1 (LASP1) in renal cell carcinoma and its significance in the invasion and migration of renal clear cell carcinoma 786-O cell line. Methods: The expression level of LASP1 in 41 cases of renal cell carcinoma tissues and normal renal tissues was analyzed by immunohistochemistry. The relationship between the expression level of LASP1 and clinical characteristics was further analyzed. Expression of LASP1 in 10 cases of tumor tissues with or without lymph node metastasis was analyzed by Western blot. Furthermore, small interfering RNA (siRNA) targeting LASP1 was constructed and transfected into 786-O cells to downregulate LASP1 expression. The interference effect of LASP1 siRNA on LASP1 protein and the expression of related proteins in epithelial mesenchymal transition (EMT) pathway were detected by Western blot. The effects of LASP1 knockdown on cell proliferation, migration and invasion and gene expression were then assessed using CCK8 assay, transwell cell migration system and western blot analysis, respectively. Results: The positive rate of LASP1 expression in renal clear cell carcinoma tissues was 90.2% (37/41), which was significantly higher than that in the adjacent tissues (29.3%, P=0.002). The expression of LASP1 in renal cell carcinoma was positively correlated with lymph node metastasis and TNM stage of renal cell carcinoma (P<0.05). The results of Western blot showed that LASP1 (0.696±0.053) was highly expressed in renal cell carcinoma (1.459±0.628), especially in cases with lymph node metastasis (2.692±0.186, P<0.05). The LASP1 siRNA remarkably down-regulated the expression of LASP1 protein in 786-O cells. The abilities of proliferation, invasion and migration of 786-O cells were decreased significantly in the LASP1 siRNA groups.The relative expression of E-cadherin protein in the siRNA group (0.848±0.020) was significantly higher than those in the siRNA-NC group (0.671±0.018) and control group (0.691±0.037, P<0.05). The relative expression of N-cadherin protein in the siRNA group (0.449±0.047) was significantly lower than those in the siRNA-NC group (0.613±0.018) and control group (0.633±0.045, P<0.05). The relative expression of vimentin protein in the siRNA group (0.477±0.029) was significantly lower than those in the siRNA-NC group (0.598±0.069) and control group (0.633±0.045, P<0.05 for both). Conclusions: LASP1 is highly expressed in renal clear cell carcinoma, which is closely related to the development of the cancer. The effects of LASP1 on the invasion and migration of 786-O cells and lymph node metastasis may be related to the EMT.

A novel redox regulator, MnTnBuOE-2-PyP5+, enhances normal hematopoietic stem/progenitor cell function.

The signaling of reactive oxygen species (ROS) is essential for the maintenance of normal cellular function. However, whether and how ROS regulate stem cells are unclear. Here, we demonstrate that, in transgenic mice expressing the human manganese superoxide dismutase (MnSOD) gene, a scavenger of ROS in mitochondria, the number and function of mouse hematopoietic stem/progenitor cells (HSPC) under physiological conditions are enhanced. Importantly, giving MnTnBuOE-2-PyP5+(MnP), a redox- active MnSOD mimetic, to mouse primary bone marrow cells or to C57B/L6 mice significantly enhances the number of HSPCs. Mechanistically, MnP reduces superoxide to hydrogen peroxide, which activates intracellular Nrf2 signaling leading to the induction of antioxidant enzymes, including MnSOD and catalase, and mitochondrial uncoupling protein 3. The results reveal a novel role of ROS signaling in regulating stem cell function, and suggest a possible beneficial effect of MnP in treating pathological bone marrow cell loss and in increasing stem cell population for bone marrow transplantation.

[Preliminary applicability evaluation of Prostate Imaging Reporting and Data System version 2 diagnostic score in 3.0T multi-parameters magnetic resonance imaging combined with prostate specific antigen density for prostate cancer].

Objective: To investigate the preliminary applicability of Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) score in the condition of 3.0T multi-parametric magnetic resonance imaging (Mp-MRI) combined with clinical classic indicators for the diagnosis of prostate cancer (PCa). Methods: The clinical and MRI materials of 247 patients of suspicious prostate disease treated in Second Affiliated Hospital of Soochow University from June 2015 to November 2016 were analyzed retrospectively, including 110 cases with PCa and 137 cases without cancer.All cases underwent the high-resolution axial T(2)-weighted imaging (T(2)WI), diffusion weighted imaging (DWI) and dynamic contrast enhancement-magnetic resonance imaging (DCE-MRI) and were confirmed pathologically by puncture biopsies.The Mp-MRI materials of all cases were scored according to PI-RADS v2.The prostate volume and prostate specific antigen (PSA) density (PSAD) value were calculated according to the formulas.The univariate and multivariate analysis were performed for the observed indicators (age, prostate volume, PSA, PSAD and PI-RADS v2 score) to determine the independent predictors for PCa.Then, a Logistic regression model (combined prediction model) was established by the independent predictors for combined diagnosis of PCa.The receiver operating characteristic curve (ROC) curve analysis was performed to get the sensitivity and specificity of each independent predictor and the model to diagnose PCa.The differences of AUC values of each independent predictor and the model were compared with each other to evaluate the diagnostic performance for PCa. Results: The differences in the age, prostate volume, PSA, PSAD and the PI-RADS v2 score between patients with PCa and non-cancer group were all statistically significant (t=2.870, Z=-4.230, -7.787, -9.477, -10.826, all P<0.05). The PSAD and PI-RADS v2 score were independent predictors for PCa (OR=3.331, 10.546, both P<0.05). The Logistic regression combined prediction model by PI-RADS v2 score and PSAD to forecast PCa was Logit(P)=-5.097+ 2.309×PSAD+ 1.214×PI-RADS v2 score.The area under the curve (AUC) of ROC in the combined model (0.911) was higher than that in the PI-RADS v2 score (0.886) and PSAD (0.851) and the differences were all statistically significant (Z=2.416, 2.716, both P<0.05); but the difference in the AUC value between PI-RADS v2 score and PSAD was not statistically significant (Z=1.191, P=0.234). The diagnostic sensitivity of PSAD, PI-RADS v2 score and the model were: 0.891, 0.782 and 0.855, respectively; the specificity were 0.449, 0.912 and 0.847, respectively on their positive thresholds (0.15 µg·L(-1)·ml(-1,) 4 and -0.82). Conclusion: PI-RADS v2 score combined with PSAD in diagnosing PCa is superior to the single application of them and it can lead to high diagnostic sensitivity and specificity for PCa.

Differential transcriptome expression in human nucleus accumbens as a function of loneliness.

Loneliness is associated with impaired mental and physical health. Studies of lonely individuals reported differential expression of inflammatory genes in peripheral leukocytes and diminished activation in brain reward regions such as nucleus accumbens, but could not address gene expression in the human brain. Here, we examined genome-wide RNA expression in post-mortem nucleus accumbens from donors (N=26) with known loneliness measures. Loneliness was associated with 1710 differentially expressed transcripts and genes from 1599 genes (DEGs; false discovery rate P<0.05, fold change ⩾|2|, controlling for confounds) previously associated with behavioral processes, neurological disease, psychological disorders, cancer, organismal injury and skeletal and muscular disorders, as well as networks of upstream RNA regulators. Furthermore, a number of DEGs were associated with Alzheimer's disease (AD) genes (that was correlated with loneliness in this sample, although gene expression analyses controlled for AD diagnosis). These results identify novel targets for future mechanistic studies of gene networks in nucleus accumbens and gene regulatory mechanisms across a variety of diseases exacerbated by loneliness.

Effect of surface free energies on the heterogeneous nucleation of water droplet: a molecular dynamics simulation approach.

Heterogeneous nucleation of water droplet on surfaces with different solid-liquid interaction intensities is investigated by molecular dynamics simulation. The interaction potentials between surface atoms and vapor molecules are adjusted to obtain various surface free energies, and the nucleation process and wetting state of nuclei on surfaces are investigated. The results indicate that near-constant contact angles are already established for nano-scale nuclei on various surfaces, with the contact angle decreasing with solid-liquid interaction intensities linearly. Meanwhile, noticeable fluctuation of vapor-liquid interfaces can be observed for the nuclei that deposited on surfaces, which is caused by the asymmetric forces from vapor molecules. The formation and growth rate of nuclei are increasing with the solid-liquid interaction intensities. For low energy surface, the attraction of surface atoms to water molecules is comparably weak, and the pre-existing clusters can depart from the surface and enter into the bulk vapor phase. The distribution of clusters within the bulk vapor phase becomes competitive as compared with that absorbed on surface. For moderate energy surfaces, heterogeneous nucleation predominates and the formation of clusters within bulk vapor phase is suppressed. The effect of high energy particles that embedded in low energy surface is also discussed under the same simulation system. The nucleation preferably initiates on the high energy particles, and the clusters that formed on the heterogeneous particles are trapped around their original positions instead of migrating around as that observed on smooth surfaces. This feature makes it possible for the heterogeneous particles to act as fixed nucleation sites, and simulation results also suggest that the number of nuclei increases monotonously with the number of high energy particles. The growth of nuclei on high energy particles can be divided into three sub-stages, beginning with the formation of a wet-spot, increase of contact angle with near-constant contact line, and finally growth with constant contact angle. The growth rate of nuclei also increases with the size of high energy particles.

Latexin sensitizes leukemogenic cells to gamma-irradiation-induced cell-cycle arrest and cell death through Rps3 pathway.

Leukemia is a leading cause of cancer death. Recently, the latexin (Lxn) gene was identified as a potential tumor suppressor in several types of solid tumors and lymphoma, and Lxn expression was found to be absent or downregulated in leukemic cells. Whether Lxn functions as a tumor suppressor in leukemia and what molecular and cellular mechanisms are involved are unknown. In this study, the myeloid leukemogenic FDC-P1 cell line was used as a model system and Lxn was ectopically expressed in these cells. Using the protein pull-down assay and mass spectrometry, ribosomal protein subunit 3 (Rps3) was identified as a novel Lxn binding protein. Ectopic expression of Lxn inhibited FDC-P1 growth in vitro. More surprisingly, Lxn enhanced gamma irradiation-induced DNA damages and induced cell-cycle arrest and massive necrosis, leading to depletion of FDC-P1 cells. Mechanistically, Lxn inhibited the nuclear translocation of Rps3 upon radiation, resulting in abnormal mitotic spindle formation and chromosome instability. Rps3 knockdown increased the radiation sensitivity of FDC-P1, confirming that the mechanism of action of Lxn is mediated by Rps3 pathway. Moreover, Lxn enhanced the cytotoxicity of chemotherapeutic agent, VP-16, on FDC-P1 cells. Our study suggests that Lxn itself not only suppresses leukemic cell growth but also potentiates the cytotoxic effect of radio- and chemotherapy on cancer cells. Lxn could be a novel molecular target that improves the efficacy of anti-cancer therapy.

Fitness penalty in susceptible host is associated with virulence of Soybean mosaic virus on Rsv1-genotype soybean: a consequence of perturbation of HC-Pro and not P3.

The multigenic Rsv1 locus in the soybean plant introduction (PI) 'PI96983' confers extreme resistance against the majority of Soybean mosaic virus (SMV) strains, including SMV-N, but not SMV-G7 and SMV-G7d. In contrast, in susceptible soybean cultivars lacking a functional Rsv1 locus, such as 'Williams82' (rsv1), SMV-N induces severe disease symptoms and accumulates to a high level, whereas both SMV-G7 and SMV-G7d induce mild symptoms and accumulate to a significantly lower level. Gain of virulence by SMV-N on Rsv1-genotype soybean requires concurrent mutations in both the helper-component proteinase (HC-Pro) and P3 cistrons. This is because of the presence of at least two resistance (R) genes, probably belonging to the nucleotide-binding leucine-rich repeat (NB-LRR) class, within the Rsv1 locus, independently mediating the recognition of HC-Pro or P3. In this study, we show that the majority of experimentally evolved mutational pathways that disrupt the avirulence functions of SMV-N on Rsv1-genotype soybean also result in mild symptoms and reduced accumulation, relative to parental SMV-N, in Williams82 (rsv1). Furthermore, the evaluation of SMV-N-derived HC-Pro and P3 chimeras, containing homologous sequences from virulent SMV-G7 or SMV-G7d strains, as well as SMV-N-derived variants containing HC-Pro or P3 point mutation(s) associated with gain of virulence, reveals a direct correlation between the perturbation of HC-Pro and a fitness penalty in Williams82 (rsv1). Collectively, these data demonstrate that gain of virulence by SMV on Rsv1-genotype soybean results in fitness loss in a previously susceptible soybean genotype, this being a consequence of mutations in HC-Pro, but not in P3.

The HC-Pro and P3 cistrons of an avirulent Soybean mosaic virus are recognized by different resistance genes at the complex Rsv1 locus.

The complex Rsv1 locus in soybean plant introduction (PI) 'PI96983' confers extreme resistance (ER) against Soybean mosaic virus (SMV) strain N but not SMV-G7 and SMV-G7d. Both the SMV helper-component proteinase (HC-Pro) and P3 cistrons can serve as avirulence factors recognized by Rsv1. To understand the genetics underlying recognition of the two cistrons, we have utilized two soybean lines (L800 and L943) derived from crosses between PI96983 (Rsv1) and Lee68 (rsv1) with distinct recombination events within the Rsv1 locus. L800 contains a single PI96983-derived member (3gG2) of an Rsv1-associated subfamily of nucleotide-binding leucine-rich repeat (NB-LRR) genes. In contrast, although L943 lacks 3gG2, it contains a suite of five other NB-LRR genes belonging to the same family. L800 confers ER against SMV-N whereas L943 allows limited replication at the inoculation site. SMV-N-derived chimeras containing HC-Pro from SMV-G7 or SMV-G7d gained virulence on L943 but not on L800 whereas those with P3 replacement gained virulence on L800 but not on L943. In reciprocal experiments, SMV-G7- and SMV-G7d-derived chimeras with HC-Pro replacement from SMV-N lost virulence on L943 but retained virulence on L800 whereas those with P3 replacement lost virulence on L800 while remaining virulent on L943. These data demonstrate that distinct resistance genes at the Rsv1 locus, likely belonging to the NB-LRR class, mediate recognition of HC-Pro and P3.

Identification and characterization of the sex-determiner transformer-2 homologue in Chinese shrimp, Fenneropenaeus chinensis.

The transformer-2 gene, encoding a protein (Tra-2) which directs sex-specifically alternative splicing of doublesex (dsx) pre-mRNA in combination with the transformer (Tra) protein, has been proved to play important roles on sex differentiation and sex development in Drosophila melanogaster. In the present study, a tra-2 homologue (FcTra-2) was cloned and characterized in the Chinese shrimp, Fenneropenaeus chinensis. A FcTra-2 genomic DNA sequence with a length of 8,871 bp was obtained and verified to consist of 7 exons and 6 introns. Three alternatively spliced mRNA transcripts, designated as FcTra-2a, FcTra-2b and FcTra-2c, were isolated and characterized. Sequence analysis showed that FcTra-2 included a RNA recognition motif and a linker region, which shared high sequence identities with Tra-2 from other species and 2 arginine/serine rich regions. Further studies were performed on the isoform FcTra-2c, since it exhibited a significantly higher expression level in ovary than in other tissues. In early developmental stages of the shrimp, FcTra-2c was detected to suddenly increase its expression level at the mysis stage. In juvenile stage, FcTra-2c displayed a significantly higher expression level in female Chinese shrimp than in males. These data indicated that FcTra-2 might be involved in female sex determination in Chinese shrimp.