核桃壳提取液用于单针藻Monoraphidium sp.QLZ-3培养产油脂

[目的] 研究核桃壳提取液（walnut shell extracts,WSE）对单针藻Monoraphidium sp.QLZ-3生长和油脂积累的影响。[方法] 向BG-11培养基中添加不同量的WSE（培养基中保留有BG-11中全部营养成分）。[结果] 结果显示,当BG-11培养基中的WSE含量为40%时,单针藻的生物量产率及油脂产率达到（534.70±4.07）mg/（L·d）和（296.35±15.36）mg/（L·d）,相比对照组分别提高了的14.82%和33.50%,蛋白质和碳水化合物含量分别有不同程度的上调和下调。与对照组相比,微藻中谷胱甘肽（glutathione,GSH）和超氧化物歧化酶（superoxide dismutase,SOD）含量与活性均上调。此外,WSE作用下,微藻对多酚的移除达到84.37%,同时上调了核酮糖1,5-二磷酸羧化酶基因（ribulose 1,5-bisphosphate carboxylase/oxygenase,rbcL）和乙酰辅酶A羧化酶（acetyl coenzyme A carboxylase,accD）基因的表达量。[结论] 研究表明,WSE联合BG-11可以提高微藻的生物量产率和油脂产率,降低微藻培养的原料成本,为核桃壳的资源化利用及微藻的工业化生产提供了一定的技术支撑。     

Electroacupuncture increased cerebral blood flow and reduced ischemic brain injury: dependence on stimulation intensity and frequency

Stroke causes ischemic brain injury and is a leading cause of neurological disability and death. There is, however, no promising therapy to protect the brain from ischemic stress to date. Here we show an exciting finding that optimal electroacupuncture (EA) effectively protects the brain from ischemic injury. The experiments were performed on rats subjected to middle cerebral artery occlusion (MCAO) with continuous monitoring of cerebral blood flow. EA was delivered to acupoints of "Shuigou" (Du 26) and "Baihui" (Du 20) with different intensities and frequencies to optimize the stimulation parameters. The results showed that 1) EA at 1.0-1.2 mA and 5-20 Hz remarkably reduced ischemic infarction, neurological deficit, and death rate; 2) the EA treatment increased the blood flow by >100%, which appeared immediately after the initiation of EA and disappeared after the cessation of EA; 3) the EA treatment promoted the recovery of the blood flow after MCAO; 4) "nonoptimal" parameters of EA (e.g., <0.6 mA or >40 Hz) could not improve the blood flow or reduce ischemic injury; and 5) the same EA treatment with optimal parameters could not increase the blood flow in naive brains. These novel observations suggest that appropriate EA treatment protects the brain from cerebral ischemia by increasing blood flow to the ischemic brain region via a rapid regulation. Our findings have far-reaching impacts on the prevention and treatment of ischemic encephalopathy, and the optimized EA parameters may potentially be a useful clue for the clinical application of EA.     

Two Phytotoxins Isolated from the Pathogenic Fungus of the Invasive Weed Xanthium italicum

Alternariol and altenuisol were isolated as the major phytotoxins produced by an Alternaria sp. pathogenic fungus of the invasive weed Xanthium italicum. Altenuisol exhibited stronger phytotoxic effect compared with alternariol. At 10 μg/mL, alternariol and altenuisol promoted root growth of the monocot plant Pennisetum alopecuroides by 11.1 % and 75.2 %, respectively, however, inhibitory activity was triggered by the increase of concentration, with root elongation being suppressed by 35.5 % and 52.0 % with alternariol and altenuisol at 1000 μg/mL, respectively. Alternariol slightly inhibited root length of the dicot plant Medicago sativa at 10–1000 μg/mL, whereas altenuisol stimulated root growth by 51.0 % at 10 μg/mL and inhibited root length by 43.4 % at 200 μg/mL. Alternariol and altenuisol did not exert strong regulatory activity on another dicot plant, Amaranthus retroflexus, when tested concentration was low, however, when the concentration reached 1000 μg/mL, they reduced root length by 68.1 % and 51.0 %, respectively. Alternariol and altenuisol exerted similar effect on shoot growth of three tested plants but to a lesser extent. It is noteworthy to mention that this is the first report on the phytotoxicity of altenuisol.     

大鼠海马神经元Na~ Ca~(2 )交换电流在低氧时的变化

目的：探讨在低氧性脑损伤发生过程中,Ｎａ＋Ｃａ２＋ 交换体在细胞内钙超载中的作用。方法：采用全细胞膜片钳方法,在急性分离海马神经元上观察低氧对Ｎａ＋Ｃａ２＋ 交换电流的电流电压（ＩＶ） 曲线的影响。结果：在整个膜电位水平,Ｎａ＋Ｃａ２＋ 交换电流幅值均不同程度的增加,在正膜电位水平呈现一显著的外向电流。１０ ｍＶ 时,电流幅值从（９２ ．８３ ±２０．８）ｐＡ上升到（１３０ ．６７ ±２６．８８）ｐＡ（ Ｐ＜０ ．０５） ,而在５０ ｍ Ｖ,其电流幅值从（－ ７４ ．６７ ±１１ ．８４）ｐＡ上升到（－ ５８ ．５±１０ ．７１）ｐＡ（Ｐ＜ ０ ．０５）。结论：低氧时Ｎａ＋Ｃａ２＋ 交换电流呈外向性,这种改变有利于低氧后通过Ｎａ＋Ｃａ２＋ 交换的外向转运方式排出细胞内钠,并交换钙进入细胞     

Multiple introductions and genetic admixture facilitate the successful invasion of Plantago virginica into China

Biological Invasions - Population genetic surveys can reveal the patterns of genetic diversity and provide insights into the details of invasion history. Plantago virginica L. (Plantaginaceae) is a...