Differentiation of spermatogonial stem cell-like cells from murine testicular tissue into haploid male germ cells in vitro

In vitro differentiation of spermatogonial stem cells (SSCs) promotes the understanding of the mechanism of spermatogenesis. The purpose of this study was to isolate spermatogonial stem cell-like cells from murine testicular tissue, which then were induced into haploid germ cells by retinoic acid (RA). The spermatogonial stem cell-like cells were purified and enriched by a two-step plating method based on different adherence velocities of SSCs and somatic cells. Cell colonies were present after culture in M1-medium for 3 days. Through alkaline phosphatase, RT-PCR and indirect immunofluorescence cell analysis, cell colonies were shown to be SSCs. Subsequently, cell colonies of SSCs were cultured in M2-medium containing RA for 2 days. Then the cell colonies of SSCs were again cultured in M1-medium for 6–8 days, RT-PCR and indirect immunofluorescence cell analysis were chosen to detect haploid male germ cells. It could be demonstrated that 10⁻⁷ mol l⁻¹ of RA effectively induced the SSCs into haploid male germ cells in vitro.     

MicroRNA profile analysis of a feline kidney cell line before and after infection with mink enteritis virus

MicroRNAs (miRNAs) are small regulatory RNAs that play a significant role in eukaryotes by targeting mRNAs for cleavage or translational repression. Recent studies have also shown them to be associated with cellular changes following viral infection. Mink enteritis virus (MEV) is one of the most important viral pathogens in the mink industry. To study the involvement of miRNAs in the MEV infection process, we used Illumina's ultrahigh throughput approach to sequencing miRNA libraries from the feline kidney (F81) cell line before and after infection with MEV. Using this bioinformatics approach we identified 196 known mammalian miRNA orthologs belonging to 152 miRNA families in F81 cells. Additionally, 97 miRNA*s of these miRNAs were detected. As well as known miRNAs, 384 and 398 novel miRNA precursor candidates were identified in uninfected and MEV-infected F81 cells respectively that have not been reported in other mammals. In MEV-infected cells 3 miRNAs were significantly down-regulated and 4 up-regulated including 3 significantly. The majority (12 of 16) of randomly selected miRNA expression profiles by qRT-PCR were consistent with those identified by deep sequencing. A total of 88 miRNAs were predicted to target interferon-associated genes; 6 appear to target the 3′UTR of MEV-specific receptor transferring receptor mRNAs; and 8 to target the MEV mRNA coding region. No miRNAs coded by MEV itself were detected.     

巴西橡胶树HbHEV3基因的克隆和表达分析

根据EST序列信息,通过RT-PCR获得了一个编码橡胶素前体的基因,命名为HbHEV3。HbHEV3编码区cDNA长度为630bp,编码209个氨基酸。预测的HbHEV3蛋白包含1个信号肽,1个具有几丁质结合特性的Hevein结构域和1个Barwinn结构域,HbHEV3与橡胶树及其他植物中类似蛋白具有很高的同源性。分离获得了HbHEV3起始密码子上游1 050bp的启动子序列,该序列含有众多应答激素和胁迫信号元件。实时荧光定量PCR分析结果表明,HbHEV3在所检测的组织中均有表达,其中在胶乳中的表达量最高,乙烯诱导能显著上调胶乳中HbHEV3的表达。研究表明,HbHEV3可能参与了橡胶树乙烯介导的防御反应,并在橡胶凝集过程中具有重要功能。     

MicroRNA miR-320a and miR-140 inhibit mink enteritis virus infection by repression of its receptor,feline transferrin receptor

Mink enteritis virus (MEV) is one of the most important pathogens in the mink industry. Recent studies have shed light into the role of microRNAs (miRNAs), small noncoding RNAs of length ranging from 18–23 nucleotides (nt), as critical modulators in the host-pathogen interaction networks. We previously showed that miRNA miR-181b can inhibit MEV replication by repression of viral non-structural protein 1 expression. Here, we report that two other miRNAs (miR-320a and miR-140) inhibit MEV entry into feline kidney (F81) cells by downregulating its receptor, transferrin receptor (TfR), by targeting the 3′ untranslated region (UTR) of TfR mRNA, while being themselves upregulated.     

MicroRNA-377 Regulates Mesenchymal Stem Cell-Induced Angiogenesis in Ischemic Hearts by Targeting VEGF

MicroRNAs have been appreciated in various cellular functions, including the regulation of angiogenesis. Mesenchymal-stem-cells (MSCs) transplanted to the MI heart improve cardiac function through paracrine-mediated angiogenesis. However, whether microRNAs regulate MSC induced angiogenesis remains to be clarified. Using microRNA microarray analysis, we identified a microRNA expression profile in hypoxia-treated MSCs and observed that among all dysregulated microRNAs, microRNA-377 was decreased the most significantly. We also validated that vascular endothelial growth factor (VEGF) is a target of microRNA-377 using dual-luciferase reporter assay and Western-blotting. Knockdown of endogenous microRNA-377 promoted tube formation in human umbilical vein endothelial cells. We then engineered rat MSCs with lentiviral vectors to either overexpress microRNA-377 (MSC^miR-377) or knockdown microRNA-377 (MSC^Anti-377) to investigate whether microRNA-377 regulated MSC-induced myocardial angiogenesis, using MSCs infected with lentiviral empty vector to serve as controls (MSC^Null). Four weeks after implantation of the microRNA-engineered MSCs into the infarcted rat hearts, the vessel density was significantly increased in MSC^Anti-377-hearts, and this was accompanied by reduced fibrosis and improved myocardial function as compared to controls. Adverse effects were observed in MSC^miR-377-treated hearts, including reduced vessel density, impaired myocardial function, and increased fibrosis in comparison with MSC^Null-group. These findings indicate that hypoxia-responsive microRNA-377 directly targets VEGF in MSCs, and knockdown of endogenous microRNA-377 promotes MSC-induced angiogenesis in the infarcted myocardium. Thus, microRNA-377 may serve as a novel therapeutic target for stem cell-based treatment of ischemic heart disease.     

40种植物丙酮提取物对朱砂叶螨的毒杀活性

为推动植物源杀螨剂的研发进程,采用玻片浸渍法测定40种植物丙酮提取物对朱砂叶螨（Tetranychus cinnabrinus）雌成螨的毒杀活性,以期发现具开发潜力的植物资源。结果表明,沙茴香（Ferula bungeana）、盐肤木（Rhus chinensis）、黄连木（Pistacia chinensis）、紫丁香（Syringa oblata）和南方六道木（Abelia dielsii）等5种植物丙酮提取物对朱砂叶螨的毒杀活性较好;毒力测定表明,沙茴香和盐肤木丙酮提取物对朱砂叶螨的毒杀活性最好,LC₅₀分别为0.08 g·mL^-1和0.09 g·mL^-1。可见,沙茴香和盐肤木可作为植物源杀螨剂研发的候选材料,值得进一步研究。     

Nosocomial Infection in Adult Admissions with Hematological Malignancies Originating from Different Lineages: A Prospective Observational Study

Background

Nosocomial infection (NI) causes prolonged hospital stays, increased healthcare costs, and higher mortality among patients with hematological malignancies (HM). However, few studies have compared the incidence of NI according to the HM lineage.

Objective

To compare the incidence of NI according to the type of HM lineage, and identify the risk factors for NI.

Methods

This prospective observational study monitored adult patients with HM admitted for >48 hours to the General Hospital of the People''s Liberation Army during 2010–2013. Attack rates and incidences of NI were compared, and multivariable logistic regression was used to control for confounding effects.

Results

This study included 6,613 admissions from 1,922 patients. During these admissions, 1,023 acquired 1,136 NI episodes, with an attack rate of 15.47% and incidence of 9.6‰ (95% CI: 9.1–10.2). Higher rates and densities of NIs were observed among myeloid neoplasm (MN) admissions, compared to lymphoid neoplasm (LN) admissions (28.42% vs. 11.00%, P<0.001 and 11.4% vs. 8.4‰, P<0.001). NI attack rates in acute myeloid leukemia (AML) and myelodysplastic/myeloproliferative neoplasm (MDS/MPN) were higher than those in MDS (30.69% vs. 20.19%, P<0.001; 38.89% vs. 20.19%, P = 0.003). Attack rates in T/NK-cell neoplasm and B-cell neoplasm were higher than those in Hodgkin lymphoma (15.04% vs. 3.65%; 10.94% vs. 3.65%, P<0.001). Multivariable regression analysis indicated prolonged hospitalization, presence of central venous catheterization, neutropenia, current stem cell transplant, infection on admission, and old age were independently associated with higher NI incidence. After adjusting for these factors, MN admissions still had a higher risk of infection (odds ratio 1.34, 95% CI: 1.13–1.59, P<0.001).

Conclusion

Different NI attack rates were observed for HM from different lineages, with MN lineages having a higher attack rate and incidence than LN lineages. Special attention should be paid to MN admissions, especially AML and MDS/MPN admissions, to control NI incidence.     

微小根毛霉致病株的原生质体形成条件

建立了重要医学真菌──肺微小根毛霉的原生质体生成系统。采用溶细胞酶以及蜗牛酶与纤维素酶联合作用的方式获得了大量原生质体,处于指数生长期、生长旺盛的幼龄菌丝对破壁酶比生长缓慢或老龄菌丝更敏感;作为渗透压稳定剂,无机盐类要好于有机物;原生质体的较适生成温度为31℃。     

甲烷代谢古菌分离培养研究进展

全球变暖是全人类面临的一个巨大挑战,而温室气体排放持续上升是全球变暖的关键因素,并引发一系列生态环境问题。甲烷是第二温室气体,对全球变暖的贡献达20%。然而,在甲烷代谢中发挥重要作用的产甲烷古菌和厌氧甲烷氧化古菌(anaerobic methanotroph,ANME)较难培养,极大地限制了人们对甲烷代谢及其影响碳源-汇关系与机制的研究。本文综述了最新产甲烷古菌和ANME富集、分离和培养方法,包括富集培养、原位培养、共培养、微流控技术、稀释分离和固体分离技术、ANME反应器和培养瓶富集培养,以及宏基因组预测和反向基因组学,并对这些方法的优缺点进行了评估,对未来甲烷代谢古菌的富集、分离和培养提出新的建议。