Cloning and functional characterization of an O-acetylserine(thiol)lyase-encoding gene in wild soybean (Glycine soja)

The terminal step of soybean cysteine synthesis is catalyzed by O-acetylserine(thiol)lyase (OAS-TL, EC 2.5.1.47). In this study, we isolated and characterized an OAS-TL gene from a wild soybean material (designated as GsOAS-TL1). GsOAS-TL1 cDNA sequence showed strict conservation at both nucleotide and amino acid levels compared with that from cultivated soybean. Genomic structure analysis of GsOAS-TL1 indicated that it contained 10 exons and 9 introns in the coding region with conserved exon sizes and intron locations compared with Arabidopsis thaliana OAS-TL-like genes. Among the complete GsOAS-TL1 cDNA and three part-deletion fragments, only expression of the full-length cDNA could rescue the NK3 cys⁻ Escherichia coli auxotroph, which was coherent with the assayed enzyme activity of purified fusion proteins. For RT-PCR analysis in different wild soybean tissues, GsOAS-TL1 showed lower expression in roots and developing seeds, whereas total OAS-TL activity of corresponding tissues showed significantly higher level in seeds than other tissues. To our knowledge, this is the first report on cloning and characterization of an OAS-TL gene from wild soybean. Our results are informative to further elucidate the function and evolution of OAS-TL in soybean.     

Frs2alpha-deficiency in cardiac progenitors disrupts a subset of FGF signals required for outflow tract morphogenesis

The cardiac outflow tract (OFT) is a developmentally complex structure derived from multiple lineages and is often defective in human congenital anomalies. Although emerging evidence shows that fibroblast growth factor (FGF) is essential for OFT development, the downstream pathways mediating FGF signaling in cardiac progenitors remain poorly understood. Here, we report that FRS2alpha (FRS2), an adaptor protein that links FGF receptor kinases to multiple signaling pathways, mediates crucial aspects of FGF-dependent OFT development in mouse. Ablation of Frs2alpha in mesodermal OFT progenitor cells that originate in the second heart field (SHF) affects their expansion into the OFT myocardium, resulting in OFT misalignment and hypoplasia. Moreover, Frs2alpha mutants have defective endothelial-to-mesenchymal transition and neural crest cell recruitment into the OFT cushions, resulting in OFT septation defects. These results provide new insight into the signaling molecules downstream of FGF receptor tyrosine kinases in cardiac progenitors.     

水稻早世代稳定718群体的获得及分析

水稻早世代稳定现象是近年来发现的一种特殊现象,其中多个早世代稳定群体是在利用来自水稻双胚苗中的多倍体与不同二倍体材料杂交得到的。本实验利用一自然突变的多倍体,与二倍体水稻太平369杂交,F_1代大部分为非整倍体,其中5株为二倍体,收取这5株二倍体上的种子,种下得到 F_2群体且定名为718群体。该群体田间观察整齐一致,经过对田间调查数据和微卫星结果的分析,表明该群体为一早世代稳定群体。     

Evidence for an Important Role of WRKY DNA Binding Proteins in the Regulation of NPR1 Gene Expression

The Arabidopsis NPR1 gene is a positive regulator of inducible plant disease resistance. Expression of NPR1 is induced by pathogen infection or treatment with defense-inducing compounds such as salicylic acid (SA). Transgenic plants overexpressing NPR1 exhibit enhanced resistance to a broad spectrum of microbial pathogens, whereas plants underexpressing the gene are more susceptible to pathogen infection. These results suggest that regulation of NPR1 gene expression is important for the activation of plant defense responses. In the present study, we report the identification of W-box sequences in the promoter region of the NPR1 gene that are recognized specifically by SA-induced WRKY DNA binding proteins from Arabidopsis. Mutations in these W-box sequences abolished their recognition by WRKY DNA binding proteins, rendered the promoter unable to activate a downstream reporter gene, and compromised the ability of NPR1 to complement npr1 mutants for SA-induced defense gene expression and disease resistance. These results provide strong evidence that certain WRKY genes act upstream of NPR1 and positively regulate its expression during the activation of plant defense responses. Consistent with this model, we found that SA-induced expression of a number of WRKY genes was independent of NPR1.     

Chelation of hypocrellin B with zinc ions with electron paramagnetic resonance (EPR) evidence of the photodynamic activity of the resulting chelate

Hypocrellin B (HB), a perylenequinone derivative, is an efficient phototherapeutic agent. The chelation of HB with Zinc ions (Zn²⁺) results in a metal chelate (Zn-HB) which exhibits considerable absorption (λ_max = 612nm) in the phototherapeutic window. The structure of this chelate has been characterized by UV-Vis, IR and mass spectra. The redox potentials of the Zn-HB chelate were E_ox = +1.1V (vs. SCE) and E_re = -0.7V (vs. SCE) as measured using the circle volt curve. The quantum yield of singlet oxygen generated by the Zn-HB chelate was 0.86, which both the electron spin trap (EPR) method and the chemical trap method show to be about 0.1 higher than that of its parent compound HB. In irradiated oxygen-saturated solutions of Zn-HB chelate, superoxide radical anions and hydroxyl radicals were detected by EPR spectroscopy using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as the spin-trapping agent.     

Pneumonia in patients with cirrhosis: risk factors associated with mortality and predictive value of prognostic models

Background

Cirrhosis always goes with profound immunity compromise, and makes those patients easily be the target of pneumonia. Cirrhotic patients with pneumonia have a dramatically increased mortality. To recognize the risk factors of mortality and to optimize stratification are critical for improving survival rate.

Methods

Two hundred and three cirrhotic patients with pneumonia at a tertiary care hospital were included in this retrospective study. Demographical, clinical and laboratory parameters, severity models and prognosis were recorded. Multivariate Cox regression analysis was used to identify independent predictors of 30-day and 90-day mortality. Area under receiver operating characteristics curves (AUROC) was used to compare the predictive value of different prognostic scoring systems.

Results

Patients with nosocomial acquired or community acquired pneumonia indicated similar prognosis after 30- and 90-day follow-up. However, patients triggered acute-on-chronic liver failure (ACLF) highly increased mortality (46.4% vs 4.5% for 30-day, 69.6% vs 11.2% for 90-day). Age, inappropriate empirical antibiotic therapy (HR: 2.326 p?=?0.018 for 30-day and HR: 3.126 p?<?0.001 for 90-day), bacteremia (HR: 3.037 p?=?0.002 for 30-day and HR: 2.651 p?=?0.001 for 90-day), white blood cell count (WBC) (HR: 1.452 p?<?0.001 for 30-day and HR: 1.551 p?<?0.001 for 90-day) and total bilirubin (HR: 1.059 p?=?0.002 for 90-day) were independent factors for mortality in current study. Chronic liver failure–sequential organ failure assessment (CLIF-SOFA) displayed highest AUROC (0.89 and 0.90, 95% CI: 0.83–0.95 and 0.85–0.95 for 30-day and 90-day respectively) in current study.

Conclusions

This study found age, bacteremia, WBC, total bilirubin and inappropriate empirical antibiotic therapy were independently associated with increased mortality. Pneumonia triggered ACLF remarkably increased mortality. CLIF-SOFA was more accurate in predicting mortality than other five prognostic models (model for end-stage liver disease (MELD), MELD-Na, quick sequential organ failure assessment (qSOFA), pneumonia severity index (PSI), Child-Turcotte-Pugh (CTP) score).

     

The effect of the SNP g.18475 A&gt;G in the 3′UTR of NCF4 on mastitis susceptibility in dairy cattle

Neutrophil cytosolic factor 4 (NCF4) is a member of the nicotinamide adenine dinucleotide phosphate oxidase subunit. This protein functions as an essential factor in the host defense against the progression of bacterial infection. To explore the variability of the NCF4 gene and the susceptibility of cows to mastitis, NCF4 functional single nucleotide polymorphism (SNP) of the 3′ untranslated region (3′UTR) and its targeted microRNA (miRNA) were identified. One SNP g.18475 A>G in the 3′UTR of NCF4 was found within the binding seed region of bta-miR-2426. We constructed two recombinant pMIR-REPORT? vectors with the A or G allele in the g.18475 locus and transiently co-transfected the vectors in human embryo kidney 293T (HEK 293T) cells, along with bta-miR-2426 mimics. A luciferase assay indicated that this SNP affects the binding of NCF4 and bta-miR-2426. In addition, the association analysis results showed that cows with the GG genotype in SNP g.18475 A>G had a relatively lower SCS value than cows with the AA genotype. Finally, quantitative real-time PCR (RT-qPCR) results showed that the cows with genotype GG had a relatively higher expression of NCF4 mRNA compared to the cows with genotype AA. NCF4 expression was regulated by the miRNA–mRNA interaction mechanism, and an important role for NCF4 in mastitis susceptibility in dairy cow was suggested.     

土壤灭菌-生物有机肥联用对连作马铃薯及土壤真菌群落结构的影响

甘肃省中部沿黄灌区是全国重要的加工型马铃薯生产基地,然而因集约化生产带来的连作障碍问题已经严重影响到当地马铃薯种植业的健康发展。结合田间试验和相关的室内分析,从马铃薯块茎产量和品质、植株生理特征和土壤真菌群落结构等角度,初步评估土壤灭菌和生物有机肥联用(Ammonia Disinfection plus Bio-organic Fertilizer Regulation,ABR)对马铃薯连作障碍的防控效果。同对照相比,ABR处理的块茎产量和商品薯率分别显著增加约71.1%—152.1%和39.2%—53.3%,但块茎化学品质变化不大。ABR处理叶绿素含量和根系活力较CK均显著增加,而叶片和根系丙二醛含量显著下降。PCR-DGGE分析发现,ABR处理显著影响了马铃薯连作土壤的真菌群落结构,表现为真菌群落的多样性指数较CK相比显著下降。ABR处理还有效抑制了土传病害的滋生,植株发病率和收获后的病薯率较CK分别显著下降约67.2%—82.2%和69.1%—70.5%。采用Real-time PCR评估连作土壤中3种优势致病真菌的数量变化,显示ABR处理下立枯丝核菌、茄病镰刀菌和接骨木镰刀菌的数量在生育期内较CK均有不同程度的下降。综合来看,土壤灭菌和生物有机肥联用技术在防控甘肃省中部沿黄灌区马铃薯连作障碍上具有较大的应用潜力,而对土传病害的抑制和微生物群落结构的改善是其主要的作用机理。