A Putative Calcium-Permeable Cyclic Nucleotide-Gated Channel, CNGC18, Regulates Polarized Pollen Tube Growth

A tip-focused Ca^2＋ gradient is tightly coupled to polarized pollen tube growth, and tip-localized influxes of extracellular Ca^2＋ are required for this process. However the molecular identity and regulation of the potential Ca^2＋ channels remains elusive. The present study has implicated CNGC18 （cyclic nucleotide-gated channel 18） in polarized pollen tube growth, because its overexpression induced wider and shorter pollen tubes. Moreover, CNGC18 overexpression induced depolarization of pollen tube growth was suppressed by lower extracellular calcium （[Ca^2＋]ex）. CNGC18-yellow fluorescence protein （YFP） was preferentially localized to the apparent post-Golgi vesicles and the plasma membrane （PM） in the apex of pollen tubes. The PM localization was affected by tip-localized ROP1 signaling. Expression of wild type ROP1 or an active form of ROP1 enhanced CNGC18-YFP localization to the apical region of the PM, whereas expression of RopGAP1 （a ROP1 deactivator） blocked the PM localization. These results support a role for PM-Iocalized CNGC18 in the regulation of polarized pollen tube growth through its potential function in the modulation of calcium influxes.     

ω-3 多不饱和脂肪酸对母婴健康结局影响的研究进展

综述了国内外研究中ω-3 PUFAs补充与妊娠期间母婴健康结局的关系以及目前推荐摄入的国家的现状和推荐后所带来的健康效益，为我国妇女在妊娠期间是否需要补充剂ω-3 PUFAs以及其推荐摄入量提供科学依据。     

Fractal root system of Melica przewalskyi along different aspect in degraded grassland

Aims Fractal root system is phenotypic plasticity result of plant root architecture to respond to environmental heterogeneity, may reflect the growth strategy of plants to adapt to environmental conditions. Our objective was to explore the relationship between root fractal dimension and fractal abundance of fractal root system of Melica przewalskyi population in response to aspect variation in the northwest of China. Methods The study site was located in a degraded alpine grassland on the northern slope in Qilian Mountains, Gansu Province, China. Survey and sampling were carried out at 40 plots which were set up along four slope aspects transects with 20 m distance between adjacent plots. Handheld GPS was used to determine the elevation, longitude and latitude of each plot. ArcGIS was used to set up digital elevation model (DEM). Community traits were investigated and six individuals roots of M. przewalskyi were collected randomly at each plot. The samples were cleaned and divided into different organs, then scanning the root with the Win-RHIZO for measurements of fractal dimension and fractal abundance in laboratory, and their biomass were then measured after being dried at 80 °C in an oven. Important findings With the slope aspect turned from north to east, west, and south, the density, height and soil moisture content of the plant community displayed a pattern of initial decline, the height, density, root fractal abundance of M. przewalskyi increased and the root fractal dimension decreased. The root fractal dimension was negatively associated with the fractal abundance in all aspects, but the relationship varied along the slope aspects gradient; there was a highly significant negative correlation (p < 0.01) between the root fractal dimension and fractal abundance at north slope and south slope aspect, whereas the correlation only reached a significant level (p < 0.05) at the east slope aspect and west slope aspect; indicating that there is a trade-off between the root fractal dimension and fractal abundance. In addition, when the slope aspect changed from north to east, west and south, the standardized major axis (SMA) slope of the regression equation in the scaling relationships between root fractal dimension and fractal abundance increased (p < 0.05), indicating that the roots of M. przewalskyi at the droughty southern slope have less branch and more sparse in the same soil volume of root exploitation and utilization. Consequently, the resource allocation pattern on reasonable trade-off between root fractal dimension and fractal abundance in different slope aspect of M. przewalskyi, reflects the relationship between the income and the cost of construction of plant root architecture.     

硒对金黄滴虫生长谷胱甘肽过氧化物酶及超微结构的影响

金黄滴虫在含硒1ppm的培养液中的生长情况和超微结构与对照组的细胞基本相同。在含硒6ppm的培养液中,前48小时细胞生长正常,以后容器中出现类似硫化氢的气味,细胞数量急剧下降,细胞变圆,运动缓慢,叶绿体变小并且绿色减退,金藻糖泡增大,在干涉显微镜下可见核仁中央下陷,成一小凹。在电镜下,核仁的中央区电子密度很低,这一区域可能相当于干涉镜下所见的小凹。在另一切面上可以看出这一区域是有开口与核基质相通的。电镜照片还揭示叶绿体结构松散,类囊体减少,在稀薄的基质中出现一些直径约为0.4—0.5μ的核仁样小体。部分细胞的线粒体形态异常,内质网及管状纤维增多。此外,作者测定了细胞谷胱甘肽过氧化物酶的活性的变化,并对硒的作用、核仁和叶绿体的变化以及核仁样小体的性质进行了讨论。     

芍药科化学和系统学的初步研究

从栽培的牡丹Paeonia suffruticosa根中分离到7个化合物,它们是芍药甙I,苯甲酰芍 药甙Ⅱ,羟基芍药甙Ⅲ,丹皮酚Ⅳ,丹皮酚甙Ⅴ,丹皮酚原甙Ⅵ和丹皮酚新甙Ⅶ。 用薄层 扫描仪测定了23种芍药科植物(包括19个种和6个变种)根中这7个成分的含量。结果表明 芍药甙在芍药科植物中是普遍存在的,可作为本科的特征性成分; 丹皮酚类成分只存在于木 本类型的牡丹组,在草本类型的芍药组中缺乏。 从化学上比较芍药科和可能相关的15个科,结果表明,芍药科与毛茛目内各科及木兰目 均不相似,而与五桠果科、茶科、蔷薇科相近; 因此建议把它提升为芍药目。这些结果与近来的解剖学、孢粉学、胚胎学的研究结果是一致的。     

大鼠隔—海马通路损伤对海马内递质含量及酶活力的影响

单侧切断大鼠海马缴和部分穹窿可使海马部分去神经。损伤后7d,海马内胆碱能系统中乙酰胆碱(ACh)含量下降72.5%,胆碱乙酰基转移酶(ChAT)活力下降45.7%,胆碱酯酶活力下降52.2%,在单胺能系统中,去甲肾上腺素(NA)含量下降16.3%,多巴胺(DA)含量下降31.3%,5-羟色胺含量下降30.3%。在损伤过程中,海马内氨基酸含量没有改变。实验结果表明,海马缴和穹窿是脑内胆碱能和单胺能传入神经到达海马靶区的部分共同通路。     

洈水水库鳡鱼(Elopichthys bambusa)生长规律的研究

本文对洈水水库鳡鱼的生长及其利用进行了分析研究,结果表明:1.该种鱼生长快,高速生长时间长,可连续5年每年生长6kg以上;2.雌、雄鱼体长与体重生长分别适合Von.Bertalanffy的生长公式:L=L_∞(1-e-k(t-t·))和W=W_∞(1-e-k(t-t·))~3;3.雌鱼体重生长速度快于雄鱼,体长生长无明显差别;4.建议大中型水体中的鳡鱼与其它鱼类群落体重之比控制在3—5％为宜。