Young Seedling Stripe1 encodes a chloroplast nucleoid-associated protein required for chloroplast development in rice seedlings

Planta - Young Seedling Stripe1 (YSS1) was characterized as an important regulator of plastid-encoded plastid RNA polymerase (PEP) activity essential for chloroplast development at rice seedling...     

猪圆环病毒2型与猪细小病毒共感染对猪肺泡巨噬细胞吞噬功能及其干扰素表达水平的影响

【目的】分析猪圆环病毒2型(PCV2)与猪细小病毒(PPV)共感染对猪肺泡巨噬细胞(PAM)吞噬功能及其干扰素表达水平的影响,为进一步阐明猪断奶后多系统衰减综合征的发病机制提供实验依据。【方法】将48头5周龄健康仔猪随机分为PCV2组、PPV组、PCV2/PPV组和对照组,每组12头。PCV2和PPV组经口鼻途径分别接种PCV2或PPV,PCV2/PPV组同时接种PCV2和PPV,对照组接种细胞营养液。感染后3、7、14和35d(dpi)从每组随机选择3头剖杀,检测PAM的存活率、吞噬活性及其α1型干扰素(IFN-α1)、γ干扰素(IFN-γ)mRNA的表达水平。【结果】PCV2组和PCV2/PPV组PAM的存活率于3、7、14dpi均低于对照组,35dpi均与对照组PAM的存活率接近,PCV2与PCV2/PPV两组之间差异不显著(P>0.05);3个病毒感染组PAM的吞噬功能均显著下降(P<0.01),其中PCV2/PPV组的吞噬功能低于PCV2组(P<0.05);PCV2/PPV组PAM中IFN-α1和IFN-γ mRNA的水平持续低于PCV2、PPV组和对照组的水平(P<0.01)。【结论】PCV2与PPV共感染没有引起PAM的活力进一步下降,但导致其吞噬功能及IFN-α1和IFN-γmRNA的表达水平持续降低。     

Development of an analytical method for organotin compounds in fortified flour samples using microwave-assisted extraction and normal-phase HPLC with UV detection

The normal high-performance liquid chromatography with UV detection was applied for the determination of tributyltin chloride (TBT), triphenyltin chloride (TPhT), tetraphenyltin (TrPhT), triethyltin chloride (TET) and tetraethyltin (TrET) from flour samples. The separation was performed in the isocratic mode on cyanopropyl column with a mobile phase of hexane-acetonitrile-THF (97/1/2). Under the experimental conditions used, quantitative limit of TBT, TPhT, TrPhT, TET and TrET are 0.95, 0.46, 0.97, 0.75 and 0.96 microg/ml, respectively. Microwave-assisted extraction of organotin (OT) compounds at 100 degrees C with an extraction time of 3 min was described. The extraction of organotin can be finished in acetic acid-hexane (20/80) medium. The quantitative extraction of five organotin compounds was achieved with recoveries ranging from 88 to 101% R.S.D. 3-8%.     

Identification of novel MiRNAs and MiRNA expression profiling during grain development in indica rice

ABSTRACT: BACKGROUND: MicroRNAs (miRNAs) modulate gene expression in different tissues and at diverse developmental stages, including grain development in japonica rice. To identify novel miRNAs in indica rice and to study their expression patterns during the entire grain filling process, small RNAs from all stages of grain development were sequenced and their expression patterns were studied using customized miRNA chips. RESULTS: A total of 21 conserved and 91 non-conserved miRNA families were found in developing indica grains. We also discovered 11 potential novel miRNAs based on the presence of their miRNA*s. Expression patterns of these identified miRNAs were analyzed using customized miRNA chips. The results showed that during the filling phase about half of the detected miRNAs were up-regulated, whereas the remainder were down-regulated. Predicted targets of differentially expressed miRNAs may participate in carbohydrate metabolism, hormone signaling and pathways associated with seed maturity, suggesting potentially important roles in rice grain development. CONCLUSIONS: This study is the first genome-wide investigation of miRNAs during the grain-filling phase of an indica variety of rice. The novel miRNAs identified might be involved in new miRNA regulatory pathways for grain development. The complexity of these miRNAs and their targets and interactions require further study to obtain a better understanding of the molecular mechanisms underlying grain development. Key words: miRNA, grain filling, indica rice.