水稻储藏过程中淀粉黏度特性的变化

对水稻淀粉黏度特性特征值测定的统计分析表明：在避光自然温度储藏期间,不同类型稻谷淀粉黏度特征值均有明显的变化,各特征值在储藏1～5个月内变化较小,而6～7个月期间变化较大,大部分特征值变化差异达到显著或极显著水平。不同类型稻谷在储藏期间黏度特征值发生明显差异的时间点不同,粳糯类水稻品种在储藏期间发生明显差异的时间点明显早于粳稻和籼稻类。储藏时间与淀粉黏度特征值优化方程建立结果显示：与籼稻类品质变化关系密切的主要特征值为最高黏度（PKV）、崩解值（BDV）和峰值时间（PeT）,粳稻类为热浆黏度（HPV）、冷胶黏度（CPV）和回复值（CSV）,而粳糯类为PKV、BDV、CSV和起浆温度（PAT）。研究结果表明,通过RVA谱主要特征值来评价不同类型水稻品种稻谷耐储藏性具有可行性。     

磁化水对小麦种子萌发、幼苗生长和生理特性的生物学效应

为研究磁化水对作物的生物学效应,本文详细分析了磁化水处理对小麦种子萌发、幼苗生长和生理特性的影响。研究结果显示：磁化水处理小麦的种子发芽参数与对照相比无显著差异;磁化水处理对小麦的株高、根长、地上部和根部鲜重等生长参数也无显著影响;同样,磁化水处理在叶片色素含量、可溶性糖、可溶性蛋白质含量、含水量、细胞汁液渗透势等重要生理特征参数方面也未显示出显著差异。此外,磁化水并未显著影响小麦叶片的光合作用。综上所述,磁化水处理对小麦种子萌发和幼苗生长无明显的生物学效应。     

外源24-表油菜素内酯对盐胁迫下茄子种子萌发和幼苗生理特性的影响

研究了150mmol·L^-1NaCI胁迫下,外源24-表油菜素内酯（EBR）对茄子种子萌发、幼苗生长和生理特性的影响。结果表明,0．05mg·L^-1外源EBR显著缓解150mmol·L^-1NaCI胁迫伤害,使茄子种子发芽率提高了8．23％,发芽势提高15．91％,发芽指数提高了17．23％,活力指数提高了44．29％;幼苗株高、根长和植株鲜重分别提高了56．67％、23．83％和56．68％;抗氧化酶（SOD、POD、CAT和APX）活性分别增加了13．75％、24．00％、28．64％和21．46％,脯氨酸和可溶性糖含量分别提高30．96％和23．66％;MDA含量、Ｏ产生速率分别降低了29．58％和14．80％。表明0．05mg·L^-1外源EBR能显著促进盐胁迫下茄子种子萌发和幼苗生长,明显缓解叶片氧化损伤,增强茄子的耐盐能力。     

马尾松幼胚体细胞胚胎发生研究

本论文首次报道了马尾松（Pinus massoniana Lamb.）幼胚体细胞胚胎发生的完整发育过程,并对影响马尾松胚性愈伤组织诱导的因素如球果采种期、球果冷藏处理时间、外植体处理方式等进行了探讨,统计胚性愈伤组织诱导率,进行增殖评价,探讨ABA浓度梯度对马尾松体细胞胚分化成熟的影响,试验数据用SPSS16统计分析软件进行方差分析、差异显著性检验。结果表明：1）2008~2009连续2年内15个采种期得到的幼胚,胚性愈伤组织诱导和增殖有显著性差异,最适宜的马尾松球果采种期是6月下旬至7月下旬,诱导率在9.66%~22.59%之间;2）球果冷藏处理时间,对胚性愈伤组织诱导有显著性差异,其中4℃冷藏球果15d有利于幼胚胚性愈伤组织诱导;3）雌配子体包含幼胚的接种处理方式是可取的;4）胚性愈伤组织经稳定增殖培养后,转入分化成熟培养基,得到体细胞胚状体＂爆发式＂分化成熟,数量多,质量好。适宜体胚成熟转化的培养基为：成熟LP培养基添加ABA5.0mg·L-1＋60.0g·L-1蔗糖,并附加L-谷氨酰胺和水解酪蛋白;5）成熟体细胞胚在无激素萌发型LP培养基上正常萌发,并转化为结构完整的小植株。本研究首次建立了马尾松幼胚体细胞胚胎发生技术平台,为马尾松遗传改良种质创新、缩短育种周期奠定了研究基础。     

外源茉莉酸甲酯对非生物胁迫下蝴蝶兰幼苗叶绿素荧光和抗氧化指标的影响

通过盆栽试验,研究了外源茉莉酸甲酯（MeJA）处理对低温、干旱和极端高温胁迫下蝴蝶兰幼苗叶绿素荧光参数和抗氧化指标的影响。结果表明,较高浓度的MeJA（150和200μmol·L-1）提高了非生物胁迫下蝴蝶兰幼苗叶片最大光化学效率（Fv/Fm）和实际光化学效率（ΦPSII）,降低了叶片相对电导率,还使得超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POD）活性升高,丙二醛（MDA）含量降低。表明MeJA作为一种生物调节剂,一定浓度的处理对蝴蝶兰幼苗抗逆性的提高具有明显效果。     

eIF2A mediates translation of hepatitis C viral mRNA under stress conditions

Translation of most mRNAs is suppressed under stress conditions. Phosphorylation of the α-subunit of eukaryotic translation initiation factor 2 (eIF2), which delivers initiator tRNA (Met-tRNA(i)) to the P site of the 40S ribosomal subunit, is responsible for such translational suppression. However, translation of hepatitis C viral (HCV) mRNA is refractory to the inhibitory effects of eIF2α phosphorylation, which prevents translation by disrupting formation of the eIF2-GTP-Met-tRNA(i) ternary complex. Here, we report that eIF2A, an alternative initiator tRNA-binding protein, has a key role in the translation of HCV mRNA during HCV infection, in turn promoting eIF2α phosphorylation by activating the eIF2α kinase PKR. Direct interaction of eIF2A with the IIId domain of the HCV internal ribosome entry site (IRES) is required for eIF2A-dependent translation. These data indicate that stress-independent translation of HCV mRNA occurs by recruitment of eIF2A to the HCV IRES via direct interaction with the IIId domain and subsequent loading of Met-tRNA(i) to the P site of the 40S ribosomal subunit.     

Receptor-ligand requirements for increased NK cell polyfunctional potential in slow progressors infected with HIV-1 coexpressing KIR3DL1*h/*y and HLA-B*57

Carriage of the natural killer (NK) receptor genotype KIR3DL1*h/*y with its HLA-B*57 ligand (*h/*y+B*57) is associated with slow time to AIDS and low viral load (VL). To provide a functional basis for these epidemiological observations, we assessed whether HIV-1-infected slow progressors (SP) carrying the *h/*y+B*57 compound genotype would have increased NK cell polyfunctional potential in comparison to SP with other killer immunoglobulin-like receptor (KIR)/HLA compound genotypes and whether this enhanced polyfunctionality was dependent upon the coexpression of both KIR3DL1*h/*y and HLA-B*57. The functional potential of NK cells was investigated by stimulating peripheral blood mononuclear cells with HLA-devoid targets or single HLA transfectants. Multiparametric flow cytometry was used to detect NK cells with seven functional profiles representing all permutations of CD107a expression and gamma interferon (IFN-γ) and tumor necrosis factor alpha (TNF-α) secretion. NK cells from individuals carrying KIR3DL1 receptor-HLA-Bw4 ligand pairs had greater trifunctional responses than those from KIR3DL1 homozygotes (hmz), who were Bw6 homozygotes. NK cells from subjects carrying the *h/*y+B*57 genotypes exhibited the highest trifunctional potential, and this was dependent on cocarriage of the NK receptor and its ligand. Trifunctional cells secreted more of each function tested on a per-cell basis than each corresponding monofunctional NK subset. Although VL influenced NK functionality, individuals with defined KIR/HLA genotypes exhibited differences in NK cell polyfunctionality that could not be accounted for by VL alone. The protective effect of HLA-B*57 on slow progression to AIDS and low VL may be mediated through its interaction with KIR3DL1 alleles to educate NK cells for potent activity upon stimulation.     

Bioenergy Plants: Hopes,Concerns and Prospectives

There are major concerns over both the security of energy supplies (declining supplies and political control) and the environmental costs associated with energy generation and use.The global consumption of carbon-containing fossil fuels for     

C_4 Plants as Biofuel Feedstocks: Optimising Biomass Production and Feedstock Quality from a Lignocellulosic Perspective

The main feedstocks for bioethanol are sugarcane (Saccharum officinarum) and maize (Zea mays),both of which are C4 grasses,highly efficient at converting solar energy into chemical energy,and both are food crops.As the systems for lignocellulosic bioethanol production become more efficient and cost effective,plant biomass from any source may be used as a feedstock for bioethanol production.Thus,a move away from using food plants to make fuel is possible,and sources of biomass such as wood from forestry and ...