The alternative pathway in cucumber seedlings under low temperature stress was enhanced by salicylic acid

The alternative pathway is a cyanide-resistant and non-phosphorylatory electron transport pathway in mitochondria of higher plants. Alternative oxidase (AOX) is the terminal oxidase of this pathway. Our present study investigated the effect of exogenous salicylic acid (SA) on alternative pathway in cucumber (Cucumis sativus L.) seedlings under low temperature stress. Results showed that during the process of low temperature stress, the alternative pathway capacity was enhanced as AOX expression increased in SA pretreated seedlings. Compared with seedlings without SA pretreatment, slower decrease of relative water content and lower levels of electrolyte leakage, H₂O₂ and malonyldialdehyde content were detected in SA pretreated seedlings. These results indicated that SA could alleviate the injury caused by low temperature on cucumber seedlings. Since the special protective functions of alternative pathway and AOX in plants, we suggested that the alternative pathway was related to SA-mediated plant resistance to environmental stresses such as low temperature.     

Removal of persistent organic pollutants from micro-polluted drinking water by triolein embedded absorbent

A new biomimetic absorbent, cellulose acetate (CA) embedded with triolein (CA-triolein), was prepared and applied for the removal of persistent organic pollutants (POPs) from micro-polluted aqueous solution. The comparison of CA-triolein, CA and granular activated carbon (GAC) for dieldrin removal was investigated. Results showed that CA-triolein absorbent gave a lowest residual concentration after 24 h although GAC had high removal rate in the first 4 h adsorption. Then the removal efficiency of mixed POPs (e.g. aldrin, dieldrin, endrin and heptachlor epoxide), absorption isotherm, absorbent regeneration and initial column experiments of CA-triolein were studied in detail. The linear absorption isotherm and the independent absorption in binary isotherm indicated that the selected POPs are mainly absorbed onto CA-triolein absorbent by a partition mechanism. The absorption constant, K, was closely related to the hydrophobic property of the compound. Thermodynamic calculations showed that the absorption was spontaneous, with a high affinity and the absorption was an endothermic reaction. Rinsing with hexane the CA-triolein absorbent can be regenerated after absorption of POPs. No significant decrease in the dieldrin removal efficiency was observed even when the absorption–regeneration process was repeated for five times. The results of initial column experiments showed that the CA-triolein absorbent did not reach the breakthrough point at a breakthrough empty-bed volume (BV) of 3200 when the influent concentration was 1–1.5 μg/L and the empty-bed contact time (EBCT) was 20 min.     

Effects of nitrate on intracellular nitrite and growth of Microcystis aeruginosa

Although nitrate is a macronutrient and can serve as good nitrogen source for many species of phytoplankton, high nitrate concentrations do not benefit the growth of phytoplankton. We hypothesise that algae cultured under high nitrate concentrations can accumulate intracellular nitrite, which is produced by nitrate reductase (NR) and can inhibit the growth of algae. To assess the validity of this hypothesis, Microcystis aeruginosa was grown under different nitrate concentrations from 3.57 to 21.43 mM in low CO₂ and high CO₂ conditions for 15 days. We observed that, with increasing nitrate concentrations, the intracellular nitrite concentrations of the alga increased and the growth rates and photosynthesis declined. When grown under high CO₂ conditions, M. aeruginosa showed lower intracellular nitrite concentrations and higher growth rates and \textP_\textm^\textchla {\text{P}}_{\text{m}}^{{\text{chl}}a} , \textR_\textd^\textchla {\text{R}}_{\text{d}}^{{\text{chl}}a} , α^chla than under low CO₂ conditions. These results suggest that the accumulation of intracellular nitrite could be the cause of inhibition of algal growth under high nitrate concentrations.     

低氧诱导因子脯氨酰羟化酶与OS－9在大鼠低氧肺动脉高压中的协同作用

目的：研究HIF-1α、PHDs及OS-9的表达变化在低氧性肺动脉高压（HPH）中的作用和意义。方法：SD大鼠随机分5组（n=8）;对照组（C组）和低氧3、7、14和21d组,常压低氧复制HPH大鼠模型。原位杂交、RT-PCR检测mRNA表达,免疫组化、Westernblot检测蛋白质表达。结果：①HIF-1αmRNA对照纽和低氧3d无明显差异,低氧14d后表达明显增高;HIF-1α蛋白质低氧3d组表达明显增高,7d达高峰;②对照组PHD1mRNA呈阳性表达,各低氧组与对照组比较差异不显著,PHD1蛋白质在对照组强阳性表达,低氧14d下降,低氧21d保持较低水平;对照组PHD2mRNA呈阳性表达,低氧3d增高,14d达到高峰,21d维持高水平,其蛋白质表达趋势与mRNA相同;对照组PHD3mRNA和蛋白质表达不明显,低氧3dmRNA明显增高,蛋白质低氧3d明显增高,低氧7d保持高水平,低氧14d和21d下降。③OS-9mRNA在对照组呈强阳性表达,低氧3d后迅速降低,14d达到最低水平;其蛋白质表达趋势与mRNA相同。相关分析表明,肺小动脉壁OS-9蛋白质表达水平与OS-9mRNA呈正相关,与RVHI、mPAP、WA％及LA％呈负相关。结论：HIF-1α、PHDs及OS-9均在大鼠HPH的发病机制中发挥作用。OS-9可能通过增强PHDs的活性来调节HIF-1α的表达,从而在HPH的发生和发展中发挥作用。     

Effects of granulosa cell mitochondria transfer on the early development of bovine embryos in vitro

The objective of this study was to determine the effect of exogenous mitochondria obtained from granulosa cells on the development of bovine embryos in vitro. We classified cumulus oocyte complexes (COCs) as good (G)- and poor (P)-quality oocytes based on cytoplasmic appearance and cumulus characteristics, and assessed mtDNA copy numbers in the G and P oocytes with real-time polymerase chain reaction (PCR). The mitochondria were isolated by fractionation and suspended in mitochondria injection buffer (MIB). Part one of the experiment consisted of the following treatments: (1) G-oocytes + sperm, (2) P-oocytes + mitochondria + MIB + sperm, (3) P-oocytes + MIB + sperm, and (4) P-oocytes + sperm. In part 2, oocytes were parthenogenetically activated. The treatments were: (1) G-oocytes, (2) P-oocytes + mitochondria + MIB, (3) P-oocytes + MIB, and (4) P-oocytes alone. The results indicated a significant difference in mtDNA copy number between G (361 113 +/- 147 114) and P (198 293 +/- 174 178) oocytes (p < 0.01). The rates of morula, blastocyst, and hatched blastocysts derived from P-oocytes + mitochondria were similar to those of G-oocytes, but significantly higher than P-oocytes without exogenous mitochondria in both the ICSI and parthenogenetic activation experiments. We found no difference in blastomere numbers between G-oocytes and P-oocytes + mitochondria in either experiment, but blastomere numbers in these two groups were significantly higher than in P-oocyte groups without exogenous mitochondria. These data suggest that mtDNA content is very important for early embryo development. Furthermore, the transfer of mitochondria from the same breed may improve embryo quality during preimplantation development.     

Epstein-Barr virus BZLF1 gene, a switch from latency to lytic infection, is expressed as an immediate-early gene after primary infection of B lymphocytes

We demonstrate here that the Epstein-Barr virus (EBV) BZLF1 gene, a switch from latent infection to lytic infection, is expressed as early as 1.5 h after EBV infection in Burkitt's lymphoma-derived, EBV-negative Akata and Daudi cells and primary B lymphocytes. Since BZLF1 mRNA is expressed even when the cells are infected with EBV in the presence of anisomycin, an inhibitor of protein synthesis, its expression does not require prerequisite protein synthesis, indicating that BZLF1 is expressed as an immediate-early gene following primary EBV infection of B lymphocytes.     

椴树阔叶红松林群落主要树种径级结构研究

椴树阔叶红松林群落主要树种径级结构研究孙伟中代力民章一平（中国科学院沈阳应用生态研究所,１１００１５）ＳｔｕｄｙｏｆＤｉａｍｅｔｅｒＢｒｅａｓｔＨｉｇｈＳｔｒｕｃｔｕｒｅｏｆｔｈｅＭａｉｎＴｒｅｅｓｉｎＴｉｌｉａＢｒｏａｄｌｅａｖｅｄＫｏｒｅａｎＰ...     

Sclerite calcification and reef-building in the fleshy octocoral genus Sinularia (Octocorallia: Alcyonacea)

Alcyonacean octocorals in tropical reefs are usually not considered as reef builders. Some Sinularia species, however, are capable of consolidating sclerites at the colony base to form spiculite. Nanwan Bay, southern Taiwan, features both fossilized and recently formed boulders composed of spiculite, thus demonstrating the role of Sinularia in contributing to the reef structure. Section radiography of an 18.5 kg spiculite boulder demonstrated a regular density banding of 3–6-mm intervals. Core survey indicated spiculite coverage of 25–30% on the live reef and of 30–40% on the uplifted boulders. Cores taken from living Sinularia revealed a distinct transition from discrete sclerites to compact spiculite and amorphous calcium carbonate cementing the sclerites. In the widespread S. gibberosa, sclerite formation appeared to start intracellularly, followed by a prolonged extracellular calcification process. At the calcification site, multiple sclerocytes formed expanded pseudopod-like membranes that interconnected, forming multicellular vesicles (MCVs) around the sclerites. The MCVs and the pseudopods disappeared at sclerite maturation, followed by degradation of the sclerocytes around the mature sclerites. At the colony base, granular vesicles were distributed among the sclerites, indicating a cementing process in progress. These findings suggest that colonies of Sinularia are able to cement sclerites and consolidate them at their base into spiculite, thus making them reef builders.     

ApCl基因在毕赤酵母中的表达

为了研究ApCl基因的功能,应用基因重组技术将ApCl基因片段克隆入大肠埃希菌—酵母穿梭质拉pGAPZαA,构建重组真核表达质拉pGAPZαA-ApCl,电转化巴斯德单赤酵母GS115,Zeocin筛选出阳性克隆转化子.通过比较转化空载体pGAPZaA和重组载体pGAPZαA-ApCl的不同菌株分别在含有高盐和高山梨醇浓度的液体培养基中生长情况,发现毕赤酵母GS115在转化ApCl基因后其抗旱、抗盐能力显著提高(约3倍),进一步验证了ApCl基因对提高生物抗逆能力有显著作用,为将来分离该蛋白及进一步研究奠定基础.