Production and selected fuel properties of biodiesel from promising non-edible oils: Euphorbia lathyris L., Sapium sebiferum L. and Jatropha curcas L

A comparative study on the composition, biodiesel production and fuel properties of non-edible oils from Euphorbia lathyris L. (EL), Sapium sebiferum L. (SS), and Jatropha curcas L. (JC) was conducted. Under optimal conditions, the FAME content and yield of the three oils were greater than 97.5 wt.% and 84.0%, respectively. The best biodiesel was produced from EL due to its high monounsaturation (82.66 wt.%, Cn: 1), low polyunsaturation (6.49 wt.%, Cn: 2, 3) and appropriate proportion of saturated components (8.78 wt.%, Cn: 0). Namely, EL biodiesel possessed a cetane number of 59.6, an oxidation stability of 10.4 h and a cold filter plug point of -11 °C. However, the cetane number (40.2) and oxidative stability (0.8 h) of dewaxed SS kernel oil (DSSK) biodiesel were low due to the high polyunsaturation (72.79 wt.%). In general, the results suggest that E. lathyris L. is a promising species for biodiesel feedstock.     

芒果APl同源基因的克隆及其生物信息学分析

我们采用RT-PCR方法克隆了2个APl同源基因全长cDNA,分别命名为MAPl-1(GenBank accession No.FJ529206)和MAPl-2(GenBank accession No.FJ529207).MAPl-1编码247个氨基酸,开放阅读框长度为741 bp,蛋白质分子量为28.54kD,等电点为8.31;MAPl-2编码248个氨基酸,开放阅读框长度为744 bp,蛋白质分子量为28.78 kD,等电点为8.70.同源性分析表明,它们的核苷酸序列与其它木本植物APl同源基因的一致性为72%～81%.实验分析表明,MAPl-1和MAPl-2第1至第61个氨基酸含有一个MADS盒结构域,第88至第178个为K盒结构域;两个基因均定位于细胞核,且功能位点分布存在着不同,推测这两个基因在花器官发育过程中的功能存在差异.蛋白二级结构预测显示,MAPl-1蛋白有12个a-螺旋,4个β折叠区,14个β-转角;而MAPl-2蛋白有11个a-螺旋,5个β折叠区,15个β-转角:其大多数氨基酸具有亲水性.本研究有助于进一步了解芒果的开花分子机理及成花的生物学发育阶段.     

Negative control of p53 by Sir2alpha promotes cell survival under stress.

The NAD-dependent histone deacetylation of Sir2 connects cellular metabolism with gene silencing as well as aging in yeast. Here, we show that mammalian Sir2alpha physically interacts with p53 and attenuates p53-mediated functions. Nicotinamide (Vitamin B3) inhibits an NAD-dependent p53 deacetylation induced by Sir2alpha, and also enhances the p53 acetylation levels in vivo. Furthermore, Sir2alpha represses p53-dependent apoptosis in response to DNA damage and oxidative stress, whereas expression of a Sir2alpha point mutant increases the sensitivity of cells in the stress response. Thus, our findings implicate a p53 regulatory pathway mediated by mammalian Sir2alpha. These results have significant implications regarding an important role for Sir2alpha in modulating the sensitivity of cells in p53-dependent apoptotic response and the possible effect in cancer therapy.     

DNA methylation changes in photoperiod-thermo-sensitive male sterile rice PA64S under two different conditions

Epigenetic modification can occur at a high frequency in crop plants and might generate phenotypic variation without changes in DNA sequences. DNA methylation is an important epigenetic modification that may contribute to environmentally-induced phenotypic variations by regulating gene expression. Rice Photoperiod-Thermo-Sensitive Genic Male Sterile (PTGMS) lines can transform from sterility to fertility under lower temperatures and short-day (SD) conditions during anther development. So far, little is known about the DNA methylation variation of PTGMS throughout the genome in rice. In this study, we investigated DNA cytosine methylation alterations in the young panicles of PTGMS line PA64S under two different conditions using methylation sensitive amplified polymorphism (MSAP) method. Compared with the DNA methylation level of PA64S under lower temperatures and SD conditions (fertility), higher methylation was observed in PA64S (sterility). The sequences of 25 differentially amplified fragments were successfully obtained and annotated. Three methylated fragments, which are homologous to D2, NAD7 and psaA, were confirmed by bisulfite sequencing and their expression levels were also evaluated by qPCR. Real time quantitative PCR analysis revealed that five of the six selected methylated genes were downregulated in PA64S (sterility). These results suggested that DNA methylation may be involved in the sterility–fertility transition of PA64S under two different environmental conditions.     

The effect of turmeric extracts on inflammatory mediator production.

Major compounds of several commonly used botanicals, including turmeric, have been purported to have anti-inflammatory actions. In order to test the anti-inflammatory activity of compounds isolated from rhizomes of Curcuma longa L. (Zingiberaceae), we have established an in vitro test system. HL-60 cells were differentiated and exposed to lipopolysaccharide (LPS) from Escherichia coli (1 microg/ml) in the presence or absence of botanical compounds for 24 h. Supernatants were collected and analyzed for the production of tumor necrosis factor alpha (TNF-alpha) and prostaglandin E2 (PGE2) using standard ELISA assays. Water-soluble extracts were not cytotoxic and did not exhibit biological activity. Organic extracts of turmeric were cytotoxic only at concentrations above 50 microg/ml. Crude organic extracts of turmeric were capable of inhibiting LPS-induced TNF-alpha (IC50 value = 15.2 microg/ml) and PGE2 (IC50 value = 0.92 microg/ml) production. Purified curcumin was more active than either demethoxy- or bisdemethoxycurcumin. Fractions and subfractions of turmeric extracts collected via preparative HPLC had differing biological activity, ranging from no activity to IC50 values of < 1 microg/ml. For some fractions, subfractionation resulted in a loss of activity, indicating interaction of the compounds within the fraction to produce an anti-inflammatory effect. A combination of several of the fractions that contain the turmeric oils was more effective than the curcuminoids at inhibiting PGE2. While curcumin inhibited COX-2 expression, turmeric oils had no effect on levels of COX-2 mRNA.