The role of the seed coat in adaptation of dimorphic seeds of the euhalophyte Suaeda salsa to salinity

The role of the seed coat in adaptation of dimorphic seeds of the euhalophyte Suaeda salsa to salinity was investigated during germination and early seedling growth. Black and brown seeds were treated with chloroform for 1 min before the extract was used to analyze waxes and the seeds to investigate the protective role of the seed coat under saline conditions. Waxes in black seed coats were more abundant than those in brown seed coats. Salinity (500 mM NaCl) increased the concentration of Na⁺ and decreased the concentration of K⁺ in both black and brown seeds regardless of chloroform treatment. Chloroform treatment alone (in the absence of NaCl) had no effect on the concentration of Na⁺ or K⁺ in black or brown seeds and in the presence of 500 mM NaCl had no effect on the concentration of Na⁺ or K⁺ in brown seeds. However, chloroform treatment increased Na⁺ and decreased K⁺ in black seeds with 500 mM NaCl. A change of MDA (malondialdehyde) concentration in black and brown seeds treated with or without chloroform was similar to the change of Na⁺ concentration. High salinity (1500 mM NaCl) pretreatment for 40 days had a less adverse effect on germination of black seeds compared with brown seeds after they were transferred to fresh water regardless of chloroform treatment. Similar results were found for seedling emergence. In conclusion, a black seed coat may be more protective than a brown seed coat, probably by shielding the embryo from ion toxicity, because of its higher content of waxes. Thus black seeds can better maintain seed viability than brown seeds for extended periods under hypersaline conditions.     

Description of whistles of Irrawaddy dolphins (Orcaella brevirostris) from the waters of Matang,Peninsular Malaysia

The whistles of Irrawaddy dolphins (Orcaella brevirostris) from the waters of Matang, western Peninsular Malaysia are described. Duration, frequency and frequency modulation variables were measured from 163 whistles recorded using a broadband towed hydrophone. Irrawaddy dolphins produced whistles with a mean duration of 0.366 s (S.D. ± 0.217 s). The fundamental frequency of whistles extended from 3040 to 17,123 Hz with low levels of frequency modulation. These dolphins produced whistles that were comparable to those of conspecifics recorded from the waters of Kalimantan, but were generally different from the related Australian snubfin dolphin (O. heinsohni). They also differed from the whistles of the sympatric Indo-Pacific humpback dolphin (Sousa chinensis). Characteristics of Irrawaddy dolphin whistles may be useful in future passive acoustic monitoring studies to investigate differences in sympatric species and their habitat.     

Design,synthesis and SAR of a novel series of heterocyclic phenylpropanoic acids as GPR120 agonists

A novel series of 5-membered heterocycle-containing phenylpropanoic acid derivatives was discovered as potent GPR120 agonists with low clearance, high oral bioavailability and in vivo antidiabetic activity in rodents.     

干旱下植物气孔运动的调控

概述了植物气孔对大气干旱和土壤干旱的反应,认为植物气孔对大气干旱的反应并不是一种反馈机制;并就干旱条件下植物气孔运动的水力学和化学信号调控机制进行了简要论述,认为虽然化学信号调控干旱下气孔运动更为广泛,但ABA不是唯一的化学信号,水分关系影响了信号的产生、运转和气孔对信号的敏感性,干旱条件下水力学和化学信号共同调控着植物的气孔运动。     

荒漠草原“土岛”生境群落物种共存机制

经过长期破碎化, 荒漠草原原生硬质灰钙土斑块散布在广大沙化土地中, 形成类似“土岛”的土被结构。为揭示土岛生境的群落物种共存机制, 2016年在宁夏盐池县皖记沟村选取大(200-300 m²)、中(约100 m²)、小(约50 m²)土岛各3个开展调查, 采用Jaccard相异系数、物种生态位宽度和生态位重叠度、零模型、Meta分析, 综合计算和分析土岛内部与外部植物群落相似性、物种生态位宽度和生态位重叠、物种共存格局及其影响因子。研究发现, (1)随着破碎化加剧, 土岛内部植物多样性整体呈现下降趋势, 群落优势种从短花针茅(Stipa breviflora)转变为猪毛蒿(Artemisia scoparia)和短花针茅共优种, 土岛内外群落相似性增加。(2)土岛内外绝大多数物种生态位重叠较小, 生态位重叠在土岛内呈集中分布, 而土岛外则呈均匀发散分布。(3)环境过滤为主的生态过程决定了土岛生境群落物种的共存格局, 随着土岛面积减小, 环境因子对群落物种共存的调控强度降低, 关键性环境因子由土壤细砂粒和黏粒转变为粗砂粒, 显著性竞争物种共存格局在小岛出现。综上所述, 土岛生境对于维持草原物种具有重要作用, 环境过滤主导了荒漠草原物种共存格局。随着生境破碎化加剧或土岛面积减小, 物种共存格局及其调控因子发生转变。保护面积在200 m²以上的大土岛对于恢复荒漠草原区草原成分种和其物种多样性机制都十分必要。     

Near-atomic structure of the inner ring of the Saccharomyces cerevisiae nuclear pore complex

Nuclear pore complexes (NPCs) mediate bidirectional nucleocytoplasmic transport of substances in eukaryotic cells. However, the accurate molecular arrangement of NPCs remains enigmatic owing to their huge size and highly dynamic nature. Here we determined the structure of the asymmetric unit of the inner ring (IR monomer) at 3.73 Å resolution by single-particle cryo-electron microscopy, and created an atomic model of the intact IR consisting of 192 molecules of 8 nucleoporins. In each IR monomer, the Z-shaped Nup188–Nup192 complex in the middle layer is sandwiched by two approximately parallel rhomboidal structures in the inner and outer layers, while Nup188, Nup192 and Nic96 link all subunits to constitute a relatively stable IR monomer. In contrast, the intact IR is assembled by loose and instable interactions between IR monomers. These structures, together with previously reported structural information of IR, reveal two distinct interaction modes between IR monomers and extensive flexible connections in IR assembly, providing a structural basis for the stability and malleability of IR.Subject terms: Cryoelectron microscopy, Nuclear pore complex     

豚鼠背侧海马锥体细胞自发放电特征

实验采用细胞外玻璃微电极采集豚鼠海马神经元放电信号,并将信号转化为峰峰间期(interspike interval,ISI)以研究麻醉和清醒状态海马锥体细胞自发放电线性和非线性特点。实验建立了豚鼠海马锥体细胞与中间神经元电生理鉴别标准;麻醉和清醒状态下豚鼠海马CA1和CA3区锥体细胞自发放电频率、时程、复杂度等无显著区别;麻醉组豚鼠海马锥体细胞ISI序列的复杂度小于清醒组,锥体细胞分型和ISI变异度等表现不同。实验表明,麻醉和清醒状态下豚鼠海马锥体细胞自发放电呈不同线性和非线性特征。传统和非线性研究手段的结合,可能较全面地反映海马锥体细胞自发放电特性。     

Preliminary Study of the Benthic Marine Algae on the Northern Bohai Sea Coast

The composition, distribution and seasonal variation of the benthic marine algae in the northern Bohai Sea coast were studied. 119 species of benthic marine algae were found in the northern Bohai Sea coast. They belong respectively to Cyanophyta, Thodophyta, Phaeophyta and Chlorophyta. The study showed that the marine algae flora of the northern Bohai Sea coast belongs to warm temperate in nature with considerable subtropical composition. There were 57 species of economic algae in the northern Bohai Sea coast and 7 newly recorded species.