Effects of diurnal temperature range on mortality in Hefei city, China.

Although several studies indicated an association between diurnal temperature range (DTR) and mortality, the results about modifiers are inconsistent, and few studies were conducted in developing inland country. This study aims to evaluate the effects of DTR on cause-specific mortality and whether season, gender, or age might modify any association in Hefei city, China, during 2007-2016. Quasi-Poisson generalized linear regression models combined with a distributed lag non-linear model (DLNM) were applied to evaluate the relationships between DTR and non-accidental, cardiovascular, and respiratory mortality. We observed a J-shaped relationship between DTR and cause-specific mortality. With a DTR of 8.3 °C as the reference, the cumulative effects of extremely high DTR were significantly higher for all types of mortality than effects of lower or moderate DTR in full year. When stratified by season, extremely high DTR in spring had a greater impact on all cause-specific mortality than other three seasons. Male and the elderly (≥ 65 years) were consistently more susceptible to extremely high DTR effect than female and the youth (< 65 years) for non-accidental and cardiovascular mortality. To the contrary, female and the youth were more susceptible to extremely high DTR effect than male and the elderly for respiratory morality. The study suggests that extremely high DTR is a potential trigger for non-accidental mortality in Hefei city, China. Our findings also highlight the importance of protecting susceptible groups from extremely high DTR especially in the spring.

AvrXa7-Xa7 mediated defense in rice can be suppressed by transcriptional activator-like effectors TAL6 and TAL11a from Xanthomonas oryzae pv. oryzicola.

The closely related plant pathogens Xanthomonas oryzae pv. oryzicola and X. oryzae pv. oryzae cause bacterial leaf streak (BLS) and bacterial leaf blight (BLB), respectively, in rice. Unlike X. oryzae pv. oryzae, endogenous avirulence-resistance (avr-R) gene interactions have not been identified in the X. oryzae pv. oryzicola-rice pathosystem, though both X. oryzae pv. oryzicola and X. oryzae pv. oryzae possess transcriptional activator-like effectors (TALE), which are known to modulate R or S genes in rice. In this report, avrXa7, avrXa10, and avrXa27 from X. oryzae pv. oryzae were transferred into YNB0-17 and RS105, hypovirulent and hypervirulent strains, respectively, of X. oryzae pv. oryzicola. When YNB0-17 containing avrXa7, avrXa10, or avrXa27 was inoculated to rice, hypersensitive responses (HR) were elicited in rice cultivars containing the R genes Xa7, Xa10, and Xa27, respectively. By contrast, RS105 expressing avrXa27 elicited an HR in a rice cultivar containing Xa27 but the expression of avrXa7 and avrXa10 in RS105 did not result in HR in rice cultivars containing Xa7 and Xa10, correspondingly. Southern blot analysis demonstrated that YNB0-17 possesses only approximately nine putative tale genes, whereas the hypervirulent RS105 contains at least 20. Although YNB0-17 contains an intact type III secretion system (T3SS), its genome is lacking the T3SS effector genes avrRxo1 and xopO, which are present in RS105. The introduction of avrRxo1 and xopO into YNB0-17 did not suppress avrXa7- or avrXa10-triggered immunity in rice. However, the transference of individual tale genes from RS105 into YNB0-17 led to the identification of tal6 and tal11a that suppressed avrXa7-Xa7-mediated defense. Thus, YNB0-17 may be a useful recipient for discovering such suppressors. This is the first report that co-evolutionally generated tale genes in X. oryzae pv. oryzicola suppress gene-for-gene defense against BLB, which may explain the lack of BLS-resistant cultivars.

Stir-fried Semen Armeniacae Amarum Suppresses Aristolochic Acid I-Induced Nephrotoxicity and DNA Adducts.

OBJECTIVE: To investigate the protective effects of stir-fried Semen Armeniacae Amarum (SAA) against aristolochic acid I (AAI)-induced nephrotoxicity and DNA adducts and elucidate the underlying mechanism involved for ensuring the safe use of Asari Radix et Rhizoma. METHODS: In vitro, HEK293T cells overexpressing Flag-tagged multidrug resistance-associated protein 3 (MRP3) were constructed by Lentiviral transduction, and inhibitory effect of top 10 common pairs of medicinal herbs with Asari Radix et Rhizoma in clinic on MRP3 activity was verified using a self-constructed fluorescence screening system. The mRNA, protein expressions, and enzyme activity levels of NAD(P)H quinone dehydrogenase 1 (NQO1) and cytochrome P450 1A2 (CYP1A2) were measured in differentiated HepaRG cells. Hepatocyte toxicity after inhibition of AAI metabolite transport was detected using cell counting kit-8 assay. In vivo, C57BL/6 mice were randomly divided into 5 groups according to a random number table, including: control (1% sodium bicarbonate), AAI (10 mg/kg), stir-fried SAA (1.75 g/kg) and AAI + stir-fried SAA (1.75 and 8.75 g/kg) groups, 6 mice in each group. After 7 days of continuous gavage administration, liver and kidney damages were assessed, and the protein expressions and enzyme activity of liver metabolic enzymes NQO1 and CYP1A2 were determined simultaneously. RESULTS: In vivo, combination of 1.75 g/kg SAA and 10 mg/kg AAI suppressed AAI-induced nephrotoxicity and reduced dA-ALI formation by 26.7%, and these detoxification effects in a dose-dependent manner (P<0.01). Mechanistically, SAA inhibited MRP3 transport in vitro, downregulated NQO1 expression in vivo, increased CYP1A2 expression and enzymatic activity in vitro and in vivo, respectively (P<0.05 or P<0.01). Notably, SAA also reduced AAI-induced hepatotoxicity throughout the detoxification process, as indicated by a 41.3% reduction in the number of liver adducts (P<0.01). CONCLUSIONS: Stir-fried SAA is a novel drug candidate for the suppression of AAI-induced liver and kidney damages. The protective mechanism may be closely related to the regulation of transporters and metabolic enzymes.

TCTP overexpression is associated with the development and progression of glioma.

Upregulation of translationally controlled tumor protein (TCTP) has been reported in a variety of malignant tumors. However, the impact of TCTP in glioma remains unclear. The objective of this study was to investigate the expression and prognostic value of TCTP in glioma patients. Western blot analysis was used to characterize the expression patterns of TCTP in 45 glioma and 22 normal brain tissues. Immunohistochemistry on a tissue microarray containing 127 cases of glioma was performed to analyze the association between TCTP expression and clinicopathological features. Compared with normal brain tissues, TCTP expression was significantly higher in glioma tissues (p <0.001). In addition, high TCTP expression in glioma was significantly associated with advanced pathological grade (p = 0.018). Kaplan-Meier analysis showed that patients with glioma and higher TCTP expression tend to have shorter overall survival time (p <0.001). In multivariate analysis, TCTP expression was proved to be an independent prognostic factor for patients with glioma (p <0.001). In conclusion, this study confirmed the overexpression of TCTP and its association with tumor progression in glioma. It also provided the first evidence that TCTP expression in glioma was an independent prognostic factor of patients, which might be a potential diagnostic and therapeutic target of glioma.

Overexpression of keratin 17 is associated with poor prognosis in epithelial ovarian cancer.

The aim of this study was to investigate the association between keratin 17 (K17) expression and the clinicopathological features of patients with epithelial ovarian cancer (EOC). K17 expression was detected by real-time quantitative RT-PCR in EOC and adjacent noncancerous tissues. In addition, K17 expression was analyzed by immunohistochemistry in 104 clinicopathologically characterized EOC cases. The expression levels of K17 mRNA and protein in EOC tissues were both significantly higher than those in noncancerous tissues. In addition, positive expression of K17 correlated with the clinical stage (p=0.001). Furthermore, Kaplan-Meier survival analysis showed that a high expression level of K17 resulted in a significantly poor prognosis of EOC patients. Multivariate analysis revealed that EOC expression level was an independent prognostic parameter for the overall survival rate of EOC patients. Our data are the first to suggest that increased K17 expression in EOC is significantly associated with aggressive progression and poor prognosis. K17 may be an important molecular marker for predicting the carcinogenesis, progression, and prognosis of EOC.

Lipoic acid attenuates the expression of adhesion molecules by increasing endothelial nitric-oxide synthase activity.

We tried to study the possible effects of lipoic acid (LA) on adhesion molecule expression and its underlying mechanism in the prevention and treatment of cardiovascular disorders. Intercellular adhesion molecule-1 (ICAM-1) expression and endothelial nitric oxide synthase (eNOS) activity were determined after endothelial cells were exposed to high glucose in the absence and presence of LA. Coincubation of endothelial cells with high glucose for 24 h resulted in a significant increase of monocyte-endothelial cell adhesion and the expression of ICAM-1 (P < 0.01). These effects were abolished by LA and LA significantly increased eNOS activities (P < 0.01). These findings suggested that LA may play a role in inhibiting expression of adhesion molecules by increasing eNOS activities.

Synthesis and cytotoxicity of novel 20-O-linked homocamptothecin ester derivatives as potent topoisomerase I inhibitors.

In an attempt to improve the antitumor activity of homocamptothecins (hCPTs), a series of novel 20-O-linked hCPT ester derivatives were first designed and synthesized based on a synthetic route, by which hCPTs are acylated with different substituted phenoxyacetic acid ester derivatives. Most of the derivatives were assayed for in vitro cytotoxicity against six human cancer cell lines KB, KB/VCR, A549, HCT-8, Bel7402, and A2780, and most of the assayed compounds exhibited good antiproliferative activity on these tumor cell lines especially on KB.

[Effect of long-term power frequency electromagnetic field exposure on proliferation and apoptosis of SRA01/04 cells].

OBJECTIVE: To investigate the effect of long-term power frequency electromagnetic field (50 Hz) exposure on the proliferation and apoptosis of human lens epithelial cells (SRA01/04 cells). METHODS: SRA01/04 cells in the exponential growth phase were exposed or sham-exposed to power frequency electromagnetic field (50 Hz, 2.3 mT) for 2 hours per day, 5 days every week. After 11 weeks of exposure, the cells were collected; the cell morphology was observed under a microscope, the cell viability was measured by MTT assay, the cell cycle and apoptosis were examined by flow cytometry, and the protein expression levels of cyclin D and proliferating cell nuclear antigen (PCNA) were determined by western blot. RESULTS: Compared with the sham-exposed SRA01/04 cells, most exposed cells became rounded and more stereoscopic, and heterochromatin gathered near the nuclear membrane in some exposed cells. The MTT assay showed that the viability of exposed cells was significantly increased compared with that of the sham-exposed cells (P < 0.05). Long-term power frequency electromagnetic field exposure led to significantly increased number of cells in S phase (P < 0.05), and the proliferation index was significantly higher in the exposed cells than in the sham-exposed cells (P < 0.05). There was no significant difference in apoptotic rate between the exposed cells and sham-exposed cells (P > 0.05). The exposed cells had significantly higher protein expression levels of cyclin D and PCNA than the sham-exposed cells (P < 0.05). CONCLUSION: Long-term power frequency electromagnetic field exposure can promote cellular proliferation and change cell cycle in SRA01/04 cells, but it has no marked effect on the apoptosis of SRA01/04 cells.

Identification of seven Xanthomonas oryzae pv. oryzicola genes potentially involved in pathogenesis in rice.

Xanthomonas oryzae pv. oryzicola (Xoc) causes bacterial leaf streak (BLS) in rice, an emerging and destructive disease worldwide. Identification of key virulence factors is a prerequisite for understanding the pathogenesis of Xoc. In this study, a Tn5-tagged mutant library of Xoc strain RS105 was screened on rice, and 27 Tn5 mutants were identified that were either non-pathogenic or showed reduced virulence in rice. Fourteen of the non-pathogenic mutants were also unable to elicit the hypersensitive response (HR) in tobacco and were designated Pth(-)/HR(-) mutants; 13 mutants showed attenuated virulence and were able to induce an HR (Vir(-)/HR(+)). Sequence analysis of the Tn5-tagged genes indicated that the 14 Pth(-)/HR(-) mutants included mutations in hrcC, hrcT, hrcV, hpaP, hrcQ, hrpF, hrpG and hrpX. The 13 Vir(-)/HR(+) mutants included tal-C10c-like (a transcriptional activator-like TAL effector), rpfC (regulator of pathogenicity factors), oxyR (oxidative stress transcriptional regulator), dsbC (disulfide isomerase), opgH (glucan biosynthesis glucosyltransferase H), rfbA (glucose-1-phosphate thymidylyltransferase), amtR (aminotransferase), purF (amidophosphoribosyltransferase), thrC (threonine synthase), trpA (tryptophan synthase alpha subunit) and three genes encoding hypothetical proteins (Xoryp_02235, Xoryp_00885 and Xoryp_22910). Collectively, the 27 Tn5 insertions are located in 21 different open reading frames. Bacterial growth and in planta virulence assays demonstrated that opgH, purF, thrC, trpA, Xoryp_02235, Xoryp_00885 and Xoryp_22910 are candidate virulence genes involved in Xoc pathogenesis. Reduced virulence in 13 mutants was restored to wild-type levels when the cognate gene was introduced in trans. Expression profiles demonstrated that the seven candidate virulence genes were significantly induced in planta, although their roles in Xoc pathogenesis remain unclear.

EcpA, an extracellular protease, is a specific virulence factor required by Xanthomonas oryzae pv. oryzicola but not by X. oryzae pv. oryzae in rice.

Previously, 12 protease-deficient mutants of the Xanthomonas oryzae pv. oryzicola (Xoc) RS105 strain were recovered from a Tn5-tagged mutant library. In the current study, the Tn5 insertion site in each mutant was mapped. Mutations in genes encoding components of the type II secretion apparatus, cAMP regulatory protein, integral membrane protease subunit, S-adenosylmethionine decarboxylase proenzyme and extracellular protease (ecpA(Xoc)) either partially or completely abolished extracellular protease activity (ECPA) and reduced virulence in rice. Transcription of ecpA(Xoc) was induced in planta in all the mutants except RΔecpA. Complementation of RΔecpA with ecpA(Xoc) in trans restored ECPA, virulence and bacterial growth in planta. Purified EcpA(Xoc) induced chlorosis- and necrosis-like symptoms similar to those induced by the pathogen when injected into rice leaves. Heterologous expression of ecpA(Xoc) conferred ECPA upon the vascular bacterium X. oryzae pv. oryzae (Xoo) and upon non-pathogenic Escherichia coli. Genetic analysis demonstrated that the C-terminal residues of EcpA in Xoo PXO99(A) and Xoc RS105 are different, and a frame shift in ecpA(Xoo) may explain the absence of EcpA activity in Xoo. Collectively, these results suggest that EcpA(Xoc) is a tissue-specific virulence factor for Xoc but not Xoo, although the two pathovars are closely related bacterial pathogens of rice.

Ketoglutarate transport protein KgtP is secreted through the type III secretion system and contributes to virulence in Xanthomonas oryzae pv. oryzae.

The phytopathogenic prokaryote Xanthomonas oryzae pv. oryzae is the causal agent of bacterial leaf blight (BB) of rice and utilizes a type III secretion system (T3SS) to deliver T3SS effectors into rice cells. In this report, we show that the ketoglutarate transport protein (KgtP) is secreted in an HpaB-independent manner through the T3SS of X. oryzae pv. oryzae PXO99(A) and localizes to the host cell membrane for α-ketoglutaric acid export. kgtP contained an imperfect PIP box (plant-inducible promoter) in the promoter region and was positively regulated by HrpX and HrpG. A kgtP deletion mutant was impaired in bacterial virulence and growth in planta; furthermore, the mutant showed reduced growth in minimal media containing α-ketoglutaric acid or sodium succinate as the sole carbon source. The reduced virulence and the deficiency in α-ketoglutaric acid utilization by the kgtP mutant were restored to wild-type levels by the presence of kgtP in trans. The expression of OsIDH, which is responsible for the synthesis of α-ketoglutaric acid in rice, was enhanced when KgtP was present in the pathogen. To our knowledge, this is the first report demonstrating that KgtP, which is regulated by HrpG and HrpX and secreted by the T3SS in Xanthomonas oryzae pv. oryzae, transports α-ketoglutaric acid when the pathogen infects rice.

Protective roles of quercetin in acute myocardial ischemia and reperfusion injury in rats.

Myocardial ischemia and reperfusion (MI/R) is associated with an intense inflammatory reaction, which may lead to myocyte injury. In this study, we investigated the effect of quercetin, an inhibitor of c-Jun N-terminal kinase on ischemia/reperfusion injury in isolated rat hearts. Rat models of MI/R were induced by coronary occlusion followed by reperfusion, treatment of rats with quercetin (1.0 mg/kg, i.v.) induced a significant reduction of infarct volume and improvements in baseline hemodynamic abnormalities (P < 0.05). Quercetin treatment also attenuated the expression of both TNF-alpha (TNF-α) and interleukin-10 (IL-10) and lowered the serum levels of inflammatory cytokine (P < 0.05). These findings suggested that quercetin treatment significantly attenuated MI/R injury primarily through anti-inflammatory effects.

[Effects of fucoidan inducing impairment of human osteosarcoma cell 143B and its mechanism].

Objective: To investigate the effects of fucoidan inducing impairment of human osteosarcoma cell 143B, as well its mechanisms. Methods: After 143B cells were treated with different concentrations of FUC (0, 0.5, 1, 10, 100, 400, 800 µg/ml) for 48 h, the cell viability and dehydrogenase (LDH) level were detected by MTT assay and chemical colorimetry with six multiple wells for each concentration. Based on MTT results, we determined the value of IC50 was 244.5 µg/ml. The follow-up experiments were divided into control group (without FUC), FUC (10 µg/ml)-treated group, FUC (100 µg/ml)-treated group, FUC (400 µg/ml)-treated group and positive group (resveratrol, 40 µmol/L). There were four multiple wells for each concentration, and each experiment was repeated at least three times. Flow cytometry was performed to detect cell apoptosis and intracellular reactive oxygen species (ROS) level; acridine orange (AO) staining and lyso-tracker red staining were used to observe the autophagolysosome formation; chemical colorimetric analysis was performed to determine malondialdehyde (MDA) content and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px); Western blot was used to detect protein expressions of nuclear factor E2-associated factor 2 (Nrf2), heme oxygenase 1 (HO-1) and autophagy-associated proteins including microtubule-associated light chain protein 3 (LC-3), Atg7, Beclin-1 and p62. Results: Compared with control group, the cell viability was decreased significantly in FUC (100～400 µg/ml)-treated groups (P＜0.01); LDH levels in the supernatant (P＜0.05 or P＜0.01), the percentage of cell apoptosis (P＜0.01), intracellular ROS level and MDA content (P＜0.01) were increased remarkably; protein expressions of Atg7 and Beclin-1 were upregulated (P＜0.05 or P＜0.01); the conversion from LC-3I to LC-3II was significant (P＜0.01) together with elevation of autophagolysosome formation (P＜0.05 or P＜0.01); while the activities of SOD and GSH-Px and protein expressions of Nrf2, HO-1 and p62 were decreased remarkably (P＜0.05 or P＜0.01). Conclusion: FUC (100～400 µg/ml) treatment induces oxidative damage and autophagic death in osteosarcoma 143B cells.

A novel regulatory role of HrpD6 in regulating hrp-hrc-hpa genes in Xanthomonas oryzae pv. oryzicola.

Xanthomonas oryzae pv. oryzicola, the causal agent of bacterial leaf streak in the model plant rice, possesses a hypersensitive response and pathogenicity (hrp), hrp-conserved (hrc), hrp-associated (hpa) cluster (hrp-hrc-hpa) that encodes a type III secretion system (T3SS) through which T3SS effectors are injected into host cells to cause disease or trigger plant defenses. Mutations in this cluster usually abolish the bacterial ability to cause hypersensitive response in nonhost tobacco and pathogenicity in host rice. In Xanthomonas spp., these genes are generally assumed to be regulated by the key master regulators HrpG and HrpX. However, we present evidence that, apart from HrpG and HrpX, HrpD6 is also involved in regulating the expression of hrp genes. Interestingly, the expression of hpa2, hpa1, hpaB, hrcC, and hrcT is positively controlled by HrpD6. Transcriptional expression assays demonstrated that the expression of the hrcC, hrpD5, hrpE, and hpa3 genes was not completely abolished by hrpG and hrpX mutations. As observed in analysis of their corresponding mutants, HrpG and HrpX exhibit contrasting gene regulation, particularly for hpa2 and hrcT. Other two-component system regulators (Zur, LrpX, ColR/S, and Trh) did not completely inhibit the expression of hrcC, hrpD5, hrpE, and hpa3. Immunoblotting assays showed that the secretion of HrpF, which is an HpaB-independent translocator, is not affected by the mutation in hrpD6. However, the mutation in hrpD6 affects the secretion of an HpaB-dependent TAL effector, AvrXa27. These novel findings suggest that, apart from HrpG and HrpX, HrpD6 plays important roles not only in the regulation of hrp genes but also in the secretion of TAL effectors.

Hpa2 required by HrpF to translocate Xanthomonas oryzae transcriptional activator-like effectors into rice for pathogenicity.

Xanthomonas oryzae pv. oryzicola, the causative agent of bacterial leaf streak, injects a plethora of effectors through the type III secretion system (T3SS) into rice cells to cause disease. The T3SS, encoded by the hrp genes, is essential for the pathogen to elicit the hypersensitive response (HR) in nonhost tobacco and for pathogenicity in host rice. Whether or not a putative lytic transglycosylase, Hpa2, interacts with a translocon protein, HrpF, to facilitate bacterial pathogenicity remains unknown. Here we demonstrated that both the hpa2 and hrpF genes are required for the pathogenicity of X. oryzae pv. oryzicola strain RS105 in rice but not for HR induction in tobacco. The expression of hpa2 was positively regulated by HrpG and HrpD6 but not by HrpX. In vivo secretion and subcellular localization analyses confirmed that Hpa2 secretion is dependent on HpaB (a T3SS exit protein) and that Hpa2 binds to the host cell membrane. Protein-protein assays demonstrated that Hpa2 interacts with HrpF. In planta translocation of AvrXa10 indicated that the mutation in hpa2 and hrpF inhibits the injection of the HpaB-dependent transcriptional activator-like (TAL) effector into rice. These findings suggest that Hpa2 and HrpF form a complex to translocate T3S effectors into plant cells for pathogenesis in host rice.

Experimental study of the mechanism of tolerance induction in dexamethasone-treated dendritic cells.

BACKGROUND: The aim of this study was to investigate the mechanisms underlying tolerance induction of dexamethasone (Dex)-treated dendritic cells (DCs). MATERIAL/METHODS: Well-grown DC2.4 cells were randomly assigned to receive control, 50 µg/L, 100 µg/L, or 200 µg/L of dexamethasone and then were cultured for 6 days. The expressions of CD80, CD86, galectin-9, and PD-L1 on the surface of DC2.4 cells were analyzed with flow cytometry and the level of IL-12 secreted by DC2.4 cells was determined by ELISA. The stimulating activity of DC2.4 cells on allogeneic T cells was assessed with mixed lymphocyte reaction. Dexamethasone-treated DC2.4 cells were co-cultured with allogeneic splenic lymphocytes and the Foxp3 expression in naive T lymphocytes was determined with flow cytometry. RESULTS: Compared with the control group, the expressions of CD80, CD86, galectin-9, and PD-L1 on the surface of DC2.4 cells exposed to different doses of dexamethasone showed no significant changes; however, dexamethasone treatment significantly reduced IL-12 secretion and inhibited DC2.4's stimulation on the proliferation of allogeneic T lymphocytes. Moreover, dexamethasone-treated DC2.4 cells effectively promoted FOXP3 expression in naive T lymphocytes. CONCLUSIONS: DC2.4 is a stable cell line with high expressions of CD80, CD86, and PD-L1. Dexamethasone does not significantly change the cell phenotype of DC2.4 cells, but inhibits the secretion of IL-12 cytokine and attenuates DC2.4's stimulation of the proliferation of allogeneic T cells. Dexamethasone-treated DC2.4 cells also effectively promote FOXP3 expression in naive T lymphocytes.

Construction of a Tn5-tagged mutant library of Xanthomonas oryzae pv. oryzicola as an invaluable resource for functional genomics.

To genome-widely mine pathogenesis-related genes of Xanthomonas oryzae pv. oryzicola (Xoc), which is the casual agent of bacterial leaf streak resulting in significant yield loss and poor quality in rice, a Tn5 transposon-mediated mutation library was generated. Twenty-five thousand transformants were produced by using Tn5 transposome, appropriately corresponding to 5 × ORF coverage of the genome, and inoculated into rice and tobacco, individually and respectively, for screening candidate virulence genes. Southern blot and thermal asymmetric interlaced polymerase chain reaction analysis of Tn5 insertion sites of randomly selected mutants suggested a random mode of transposition and a saturation library. Characterization of extracellular polysaccharides, extracellular protease activity, and pigment production of individual mutants in the growth media revealed that 11 mutants enhanced in growth, 12 reduced extracellular polysaccharide production, 12 lost extracellular protease activity completely or partially, and 21 were pigment deficient. In planta pathogenicity assays revealed 253 mutants reduced virulence in rice, but kept triggering hypersensitive response in tobacco; 49 lost the ability to elicit HR in tobacco and pathogenicity in rice; and 3 still induced hypersensitive response in tobacco, but lost pathogenicity in rice. The achieved mutant library of Xoc is of high-quality and nearly saturated and candidate virulence mutants provided a strong basis for functional genomics of Xoc.

Comparative investigations on the protective effects of rhodioside, ciwujianoside-B and astragaloside IV on radiation injuries of the hematopoietic system in mice.

The aim of this study was to investigate the protective effects of three glycosides (rhodioside, ciwujianoside-B and astragaloside IV) on the hematopoietic system in the mice exposed to γ-rays, and to examine the possible mechanisms involved. Mice were pretreated with the glycosides (40 mg/kg, i.g.) daily for 7 days prior to radiation. The survival of mice pretreated with three glycosides after total body irradiation (6.0 Gy) was examined. Peripheral blood leucocytes and endogenous spleen colony counts, colony-forming unit-granulocyte macrophage assay, analysis of DNA content and apoptosis rate determination were performed to evaluate the effects of the three glycosides on hematogenesis. The fragmentation of double-stranded DNA in lymphocytes was detected by the comet assay. The changes in cell cycle were analysed by flow cytometry. Furthermore, the expression levels of Bcl-2, Bax and nuclear factor-kappa B (NF-κB) were measured by western blot and the electrophoretic mobility shift assay. The results showed that pretreatment with all of the glycosides improved survival time and increased the number of leucocytes, spleen colonies and granulocyte-macrophage colonies in mice exposed to 6.0 Gy γ-radiation. Rhodioside showed more protective efficacy than both ciwujianoside-B and astragaloside IV. All three glycosides significantly increased the proliferation abilities of bone marrow cells, and decreased the ratio of cells in G(0)/G(1) phase. Further analysis showed that these three glycosides were able to decrease DNA damage and the increment in the Bax/Bcl-2 ratio induced by radiation. In summary, the three glycosides showed radioprotective effects on the hematopoietic system in mice, which was associated with changes in the cell cycle, a reduction in DNA damage, and down-regulation of the ratio of Bax/Bcl-2 in bone marrow cells exposed to radiation.

Origin, Evolution, Breeding, and Omics of Chayote, an Important Cucurbitaceae Vegetable Crop.

Chayote (Sechium edule), a member of the Cucurbitaceae family, is cultivated throughout tropical and subtropical regions of the world and utilized in pharmaceutical, cosmetic and food industries because it is an excellent source of minerals, dietary fibers, protein, vitamins, carotenoids, polysaccharides, phenolic and flavonoid compounds, and other nutrients. Chayote extracts process various medicinal properties, such as anti-cardiovascular, antidiabetic, antiobesity, antiulcer, and anticancer properties. With the rapid advancements of molecular biology and sequencing technology, studies on chayote have been carried out. Research advances, including molecular makers, breeding, genomic research, chemical composition, and pests and diseases, regarding chayote are reviewed in this paper. Future exploration and application trends are briefly described. This review provides a reference for basic and applied research on chayote, an important Cucurbitaceae vegetable crop.

[Establishment of the hrp-inducing systems for the expression of the hrp genes of Xanthomonas oryzae pv. oryzicola].

The hrp genes of Xanthomonas oryzae pv. oryzicola (Xooc), which is the causal agent of bacterial leaf streak in rice, possesses the ability to elicit hypersensitive response on nonhost plants and the pathogenicity in host rice. In order to analyze the function of the hrp genes, we developed hrp-inducing systems using transcriptional hrp: :gfp fusions with the promoters of hrpX and hpa 1 of Xooc. The levels of GFP protein expression indicated that the hrp gene expression in Xooc was not efficiently induced in NB medium, but efficiently in XOM3 medium. Using the hrpG and hrpX mutants of Xooc as the controls, the results by RT-PCR demonstrated that in wild type strain the expression of the hpa1 gene was suppressed in NB medium, but was increased in XOM3 medium. When incubated in XOM3, the expression of the hpa1 gene was abolished in hrpX mutant, while the level of the hpa1 gene expression was lower in the hrpG mutant than that in wild-type strain. More importantly, it was found that the induction of the hrp gene expression was strongly increased in response to rice suspension cells and callus in this study. This suggests that the hrp-inducing systems, XOM3 or rice suspension cells or rice callus, for the induction of the hrp genes expression be useful for functionally analyzing the hrp genes, mining effectors secreted by the type III secretion apparatus and understanding pathogenicity determinats of Xooc.