不同质量浓度NaNO3对3种微藻生长及总脂肪酸含量和组成的影响

以BG11为基本培养液,研究了不同质量浓度NaNO3(37.5～1 875.0 mg·L-1)对微藻P9(Klebsormidium sp. )、TH6(Oedocladium sp. )和CF5(Stigonema sp. )生长及总脂肪酸含量和组成的影响.结果显示,调整(减少或增加)培养液中NaNO3的质量浓度,对3种微藻的生长量及总脂肪酸含量和脂肪酸组成均有一定的影响;NaNO3的质量浓度较低(37.5或75.0 mg·L-1),3种微藻的鲜质量随培养时间的延长呈先逐渐增加然后略有降低的趋势;而在NaNO3质量浓度为150.0～1 875.0 mg·L-1的条件下,在一定的培养时间(18～33 d)内,3种微藻的鲜质量均逐渐增加;总体上看,3种微藻的生长量随NaNO3质量浓度的提高呈现逐渐增加的趋势,但仅在含1 875.0 mg·L-1 NaNO3的培养液中3种微藻的生长量高于对照(1 500.0 mg·L-1NaNO3).在含375.0 mg·L-1NaNO3的培养液中培养33 d,微藻 P9的总脂肪酸含量最高(25.39%),是对照的 1.79 倍,软脂酸、亚油酸、油酸和硬脂酸的相对含量分别是对照的2.50、2.72、2.24和2.08倍;在含37.5 mg·L-1 NaNO3的培养液中培养33 d,微藻TH6的总脂肪酸含量最高(20.69%),是对照的 1.89倍,软脂酸、亚油酸和油酸的相对含量分别是对照的3.37、1.79和1.92倍;不同处理组间微藻CF5的总脂肪酸含量及组成有一定差异,但随着NaNO3质量浓度的提高变化趋势不明显.研究结果表明,适当提高培养液中的NaNO3浓度对微藻的生长有一定的促进作用,不同种类微藻适宜的NaNO3浓度有一定的差异.综合考虑生长量和总脂肪酸含量及脂肪酸组成等因素,确定适宜于微藻P9、TH6和CF5培养的NaNO3质量浓度分别为375.0、37.5和150.0 mg·L-1.     

线粒体DNA及其提取方法

线粒体是存在于绝大多数真核细胞内的一种基本的重要的细胞器,其具有相对独立的遗传系统。线粒体基因在真核生物具有高保守性,线粒体DNA(mtDNA)已被广泛应用于发病机理、临床诊断、遗传变异、生物进化等多方面的研究。1981年,Anderson用氯化铯密度梯度分离得到线粒体DNA(mtDNA),进行了全序列分析。此后,mtDNA的研究日益得到重视。已有的mtDNA提取方法概括起来可分为密度梯度离心法、酶消化法、柱层析法、氯化铯超速离心法、碱变性法和改进高盐沉淀法等,通过对以上方法的比较,发现改进高盐沉淀法具有简便、经济、易重复等优点。     

播期对陇中黄土高原半干旱区马铃薯生长发育及产量的影响

在气候变化的背景下,为了探寻陇中黄土高原半干旱区马铃薯的适宜播种期,2010年在甘肃定西进行了马铃薯分期播种试验,并对不同播期条件下马铃薯生长发育及产量形成进行了分析.结果表明:随着播期的推迟,马铃薯全生育期缩短,株高出现明显变化,单株干物质最大积累速率提前;从不同播期来看,5月27日播种的植株高度、叶面积指数、单株干物质积累量和最大积累速率均最大,马铃薯块茎鲜重的增长过程呈“慢-快-慢”S型曲线;块茎鲜重最大积累速率出现的时间随播期的推迟而提前;产量数据的方差和多重比较分析结果表明,播期是影响产量的主要因素,其中5月27日播期的丰产性最好;对各播期不同生育期的气候条件进行比较表明,5月底或6月初是陇中黄土高原半干旱区马铃薯的适宜播种时间.     

ITE and TCDD Differentially Regulate the Vascular Remodeling of Rat Placenta via the Activation of AhR

Vascular remodeling in the placenta is essential for normal fetal development. The previous studies have demonstrated that in utero exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, an environmental toxicant) induces the intrauterine fetal death in many species via the activation of aryl hydrocarbon receptor (AhR). In the current study, we compared the effects of 2-(1′H-indole-3′-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) and TCDD on the vascular remodeling of rat placentas. Pregnant rats on gestational day (GD) 15 were randomly assigned into 5 groups, and were exposed to a single dose of 1.6 and 8.0 mg/kg body weight (bw) ITE, 1.6 and 8.0 µg/kg bw TCDD, or an equivalent volume of the vehicle, respectively. The dams were sacrificed on GD20 and the placental tissues were gathered. The intrauterine fetal death was observed only in 8.0 µg/kg bw TCDD-exposed group and no significant difference was seen in either the placental weight or the fetal weight among all these groups. The immunohistochemical and histological analyses revealed that as compared with the vehicle-control, TCDD, but not ITE, suppressed the placental vascular remodeling, including reduced the ratio of the placental labyrinth zone to the basal zone thickness (at least 0.71 fold of control), inhibited the maternal sinusoids dilation and thickened the trophoblastic septa. However, no marked difference was observed in the density of fetal capillaries in the labyrinth zone among these groups, although significant differences were detected in the expression of angiogenic growth factors between ITE and TCDD-exposed groups, especially Angiopoietin-2 (Ang-2), Endoglin, Interferon-γ (IFN-γ) and placenta growth factor (PIGF). These results suggest ITE and TCDD differentially regulate the vascular remodeling of rat placentas, as well as the expression of angiogenic factors and their receptors, which in turn may alter the blood flow in the late gestation and partially resulted in intrauterine fetal death.     

Temperature,energy metabolism,and adaptive divergence in two oyster subspecies

Comparisons of related species that have diverse spatial distributions provide an efficient way to investigate adaptive evolution in face of increasing global warming. The oyster subjected to high environmental selections is a model species as sessile marine invertebrate. This study aimed to detect the adaptive divergence of energy metabolism in two oyster subspecies from the genus Crassostrea—C. gigas gigas and C. gigas angulata—which are broadly distributed along the northern and southern coasts of China, respectively. We examined the effects of acute thermal stress on energy metabolism in two oyster subspecies after being common gardened for one generation in identical conditions. Thermal responses were assessed by incorporating physiological, molecular, and genomic approaches. Southern oysters exhibited higher fluctuations in metabolic rate, activities of key energetic enzymes, and levels of thermally induced gene expression than northern oysters. For genes involved in energy metabolism, the former displayed higher basal levels of gene expression and a more pronounced downregulation of thermally induced expression, while the later exhibited lower basal levels and a less pronounced downregulation of gene expression. Contrary expression pattern was observed in oxidative stress gene. Besides, energy metabolic tradeoffs were detected in both subspecies. Furthermore, the genetic divergence of a nonsynonymous SNP (SOD‐132) and five synonymous SNPs in other genes was identified and validated in these two subspecies, which possibly affects downstream functions and explains the aforementioned phenotypic variations. Our study demonstrates that differentiations in energy metabolism underlie the plasticity of adaptive divergence in two oyster subspecies and suggest C. gigas angulata with moderate phenotypic plasticity has higher adaptive potential to cope with exacerbated global warming.     

Five New Guaiane Sesquiterpenes from the Endophytic Fungus Xylaria sp. YM 311647 of Azadirachta indica

Five new guaiane sesquiterpenes, 1 – 5 , were isolated from the culture broth of the endophytic fungus Xylaria sp. YM 311647, isolated from Azadirachta indica A. Juss . The structures of these compounds were elucidated on the basis of spectroscopic analyses, and their inhibitory activities against five pathogenic fungi were evaluated. All guaiane sesquiterpenes showed moderate or weak antifungal activities in a broth microdilution assay.     

红瘰疣螈的体温调节

红瘰疣螈(Tylototriton shanjing)为我国Ⅱ级重点保护野生动物。本实验测定了在不同环境温度条件下红瘰疣螈体温及代谢率变化。结果表明,在10～35℃环境温度范围内红瘰疣螈体温(Tb)与环境温度(Ta)呈正相关,其直线回归方程为:Tb=3.99+0.86Ta(R2=0.99,P0.01);其代谢率(MR)在15～30℃的环境温度范围内随环境温度的升高而升高,在35℃时,其代谢率由于体温过高而急剧降低;在15～35℃之间的6个温度条件下雄性代谢率的回归方程为:MR1=0.374 1-0.355 1Ta+0.113 9T2a-0.010 5T3a(R2=0.47,P0.01,df1=3,df2=46);雌性代谢率的回归方程为:MR2=0.478 8-0.420 3Ta+0.130 4T2a-0.011 8T3a(R2=0.40,P0.01,df1=3,df2=46)。不同于内热源动物的代谢特征,红瘰疣螈的体温调节表现出外热源动物的特点:其体温受环境影响较大,体温生理调节能力较弱。     

余甘子种子的抗逆生理特性及其对天然更新的影响

余甘子（Phylanthus emblica）是干热河谷植被的重要特征种和建群树种。本文通过模拟金沙江干热河谷典型地区元谋盆地4月气候条件下,研究了余甘子种子的活力散失机制及其有关生理生化变化情况,并对余甘子天然群落的自然更新状况进行了调查。结果表明: 随着高温干旱处理时间延长,种子活力不断降低,相对电导率、Pro含量和MDA含量呈持续上升趋势;呼吸强度、SOD活性、POD活性、CAT活性、可溶性糖含量呈单峰曲线变化;膜保护酶系统活力降低和保护性物质含量减少是造成种子活力下降的主要因素;实验处理的第18天至第24天是余甘子种子抵御逆境的临界期;每年3月下旬至4月上、中旬,应采取人工辅助措施来提高其种子的天然更新能力。