Nitrosothiol Formation and Protection against Fenton Chemistry by Nitric Oxide-induced Dinitrosyliron Complex Formation from Anoxia-initiated Cellular Chelatable Iron Increase

Dinitrosyliron complexes (DNIC) have been found in a variety of pathological settings associated with ^•NO. However, the iron source of cellular DNIC is unknown. Previous studies on this question using prolonged ^•NO exposure could be misleading due to the movement of intracellular iron among different sources. We here report that brief ^•NO exposure results in only barely detectable DNIC, but levels increase dramatically after 1–2 h of anoxia. This increase is similar quantitatively and temporally with increases in the chelatable iron, and brief ^•NO treatment prevents detection of this anoxia-induced increased chelatable iron by deferoxamine. DNIC formation is so rapid that it is limited by the availability of ^•NO and chelatable iron. We utilize this ability to selectively manipulate cellular chelatable iron levels and provide evidence for two cellular functions of endogenous DNIC formation, protection against anoxia-induced reactive oxygen chemistry from the Fenton reaction and formation by transnitrosation of protein nitrosothiols (RSNO). The levels of RSNO under these high chelatable iron levels are comparable with DNIC levels and suggest that under these conditions, both DNIC and RSNO are the most abundant cellular adducts of ^•NO.     

miR-homoHSV of Singapore Grouper Iridovirus (SGIV) Inhibits Expression of the SGIV Pro-apoptotic Factor LITAF and Attenuates Cell Death

Growing evidence demonstrates that various large DNA viruses could encode microRNAs (miRNAs) that regulate host and viral genes to achieve immune evasion. In this study, we report that miR-homoHSV, an miRNA encoded by Singapore grouper iridovirus (SGIV), can attenuate SGIV-induced cell death. Mechanistically, SGIV miR-homoHSV targets SGIV ORF136R, a viral gene that encodes the pro-apoptotic lipopolysaccharide-induced TNF-α (LITAF)-like factor. miR-homoHSV suppressed exogenous and endogenous SGIV LITAF expression, and thus inhibited SGIV LITAF-induced apoptosis. Meanwhile, miR-homoHSV expression was able to attenuate cell death induced by viral infection, presumably facilitating viral replication through the down-regulation of the pro-apoptotic gene SGIV LITAF. Together, our data suggest miR-homoHSV may serve as a feedback regulator of cell death during viral infection. The findings of this study provide a better understanding of SGIV replication and pathogenesis.     

The 1973 WHO Classification Is More Suitable than the 2004 WHO Classification for Predicting Prognosis in Non-Muscle-Invasive Bladder Cancer

Background

Predicting the recurrence and progression of Non-muscle-invasive bladder cancer(NMIBC) is critical for urologist. Histological grade provides significant prognostic information, especially for prediction of progression. Currently, the 1973 and the 2004 WHO classification co-exist. Which system is better for predicting rumor recurrence and progression still a matter for debate.

Methodology/Principal Findings

348 patients diagnosed with Non-muscle invasive bladder cancer were enrolled in our retrospective study. Paraffin sections were assessed by an experienced urological pathologist according to both the 1973 and 2004 WHO classifications. Tumor recurrence and progression was followed-up in all patients. During follow-up, corresponding 5-year recurrence-free survival rates of G1, G2 and G3 were 82.1%, 55.9%, 32.1% and the 5-year progression-free survival rates were 95.9%, 84.4% and 43.3%, respectively. The 5-year recurrence-free survival rates of papillary urothelial neoplasm of low malignant potential (PUNLMP), low-grade papillary urothelial carcinoma(LGPUC) and high-grade papillary urothelial carcinoma (HGPUC) were 69.8%, 67.1% and 42.0% respectively and the 5-year progression-free survival rates were 100%, 90.9% and 54.8% respectively. In multivariate analysis, the 1973 WHO classification significantly associated with both tumor recurrence and progression(p = 0.010 and p = 0.022, respectively); the 2004 WHO classification correlated with tumor progression(p = 0.019), while was not proved to be a variable that can predict the risk of recurrence(p = 0.547). Kaplan-Meier plots showed that both the 1973 WHO and the 2004 WHO classifications were significantly associated with progression-free survival (p<0.0001, log-rank test). For prediction of recurrence, significant differences were observed between the tumor grades classified using the 1973 WHO grading system (p<0.0001, log-rank test), while a significant overlap was observed between PUNLMP and LG plots using the 2004 WHO grading system(p = 0.616, log-rank test).

Conclusion/Significance

Both the 1973 WHO and the 2004 WHO Classifications are effective in predicting tumor progression in Non-muscle invasive bladder cancer, while the 1973 WHO Classification is more suitable for predicting tumor recurrence.     

富营养化对白洋淀底栖-浮游耦合食物网结构和功能的影响

国际湖沼学的长期研究发现,一个完整的湖泊生态系统应包括底栖食物网和浮游食物网,而营养条件变化会显著改变浅水湖泊中底栖-浮游食物网的结构和功能。为了明晰富营养化对浅水湖泊底栖-浮游耦合食物网结构和功能的影响,以浅水草型湖泊——白洋淀为研究区,运用野外监测和ECOSIM与ECOPATH(Ew E)模型相结合方法,构建白洋淀底栖-浮游耦合食物网的概念模型,模拟1982—2011年间富营养化对白洋淀底栖路径和浮游路径的结构和功能影响:(1)野外监测的结果表明,从1999年至今白洋淀一直处于富营养化状态;(2)Ew E模型模拟结果表明1982—2006年,总生物量呈下降趋势,下降比例达66.38%;能流路径从以底栖路径为主转变为以浮游路径为主;(3)运用Pearson相关分析,结果表明:浮游植物与TN(r=0.67,P0.01)和TP(r=0.37,P0.05)呈显著正相关,而底栖藻类和大型沉水植物与TN(r=0.77,P0.01;r=0.67,P0.01)和TP(r=0.54,P0.01;r=0.36,P0.05)呈显著负相关。富营养化是白洋淀底栖初级和次级生产力向浮游初级和次级生产力转变的主要驱动力。采用科学的方法准确评估富营养化对湖泊底栖-浮游耦合食物网结构和功能的影响,可为湖泊生态系统管理提供技术和方法支持。     

AFLP分子标记技术的改进

对AFLP技术的限制性内切酶组合进行了改进。以两个低频酶组合代替传统的高频酶与低频酶组合进行分子标记筛选,结果表明,采用低频酶组合(EcoRⅠ PstⅠ)产生的条带比传统酶切组合(EcoRⅠ MseⅠ和PstⅠ MseⅠ)要少且分布不均匀,多集中在150~800bp之间,条带信号强度要大,多态性明显得到提高,分子标记筛选成功率也得到了提高,而且其成本更低的特点有利于AFLP技术在我国的进一步推广普及。