旧石器时代石制品热处理研究:回顾与展望

热处理技术作为旧石器时代古人类提高石器制作工艺水平的代表性技能, 一直以来倍受国际学术界的重视, 在已经开展的40余年工作中积累了丰硕的研究成果。由于我国旧石器时代石料的特点及热处理研究的某些技术手段本身存在局限性, 尚未在考古遗址中发现热处理行为及相关遗物, 目前我国热处理研究仍处于空白阶段。本文主要介绍旧石器时代热处理技术的原理与工艺及相关研究手段, 特别是针对热处理技术的实验研究。相信随着认识的加深, 石制品热处理研究会在我国旧石器考古学研究中发挥重要作用。     

The enzymatic activity of Arabidopsis protein arginine methyltransferase 10 is essential for flowering time regulation

Arabidopsis AtPRMT10 is a plant-specific type I protein arginine methyltransferase that can asymmetrically dimethylate arginine 3 of histone H4 with auto-methylation activity. Mutations of AtPRMT10 derepress FLOWERING LOCUS C (FLC) expression resulting in a late-flowering phenotype. Here, to further investigate the biochemical characteristics of AtPRMT10, we analyzed a series of mutated forms of the AtPRMT10 protein. We demonstrate that the conserved “VLD” residues and “double-E loop” are essential for enzymatic activity of AtPRMT10. In addition, we show that Arg54 and Cys259 of AtPRMT10, two residues unreported in animals, are also important for its enzymatic activity. We find that Arg13 of AtPRMT10 is the auto-methylation site. However, substitution of Arg13 to Lys13 does not affect its enzymatic activity. In vivo complementation assays reveal that plants expressing AtPRMT10 with VLD-AAA, E143Q or E152Q mutations retain high levels of FLC expression and fail to rescue the late-flowering phenotype of atprmt10 plants. Taken together, we conclude that the methyltransferase activity of AtPRMT10 is essential for repressing FLC expression and promoting flowering in Arabidopsis.     

神经病靶标酯酶调控结构域结合蛋白筛选及其在COS-7细胞中的表达

本研究采用酵母双杂交系统探寻与神经病靶标酯酶（NTE）调控结构域相互作用的蛋白因子,揭示与NTE信号转导相关的可能机制。通过构建含有NTE调控结构域的诱饵蛋白载体筛选胎脑文库,并将筛选得到的阳性克隆在酵母中进行了验证,随后在哺乳动物细胞中表达了该蛋白。生物信息学分析显示：该阳性克隆为前列腺素受体结合蛋白54（ARA54）,具有泛素连接酶活性,提示细胞可能存在依赖于细胞周期的NTE活性调节机制,为阐明NTE生理功能创造了条件[动物学报51（5）：840—844,2005]。     

Experimental study on the impact of dinoflagellate Alexandrium species on populations of the rotifer Brachionus plicatilis

To investigate harmful effects of the dinoflagellate Alexandrium species on microzooplankton, the rotifer Brachionus plicatilis was chosen as an assay species, and tested with 10 strains of Alexandrium including one known non-PSP-producer (Alexandrium tamarense, AT-6). HPLC analysis confirmed the PSP-content of the various strains: Alexandrium lusitanicum, Alexandrium minutum and Alexandrium tamarense (ATHK, AT5-1, AT5-3, ATCI02, ATCI03) used in the experiment were PSP-producers. No PSP toxins were detected in the strains Alexandrium sp1, Alexandrium sp2.Exposing rotifer populations to the densities of 2000 cells ml⁻¹ of each of these 10 Alexandrium strains revealed that the (non-PSP) A. tamarense (AT-6) and two other PSP-producing algae: A. lusitanicum, A. minutum, did not appear to adversely impact rotifer populations. Rotifers exposed to these three strains were able to maintain their population numbers, and in some cases, increase them. Although some increases in rotifer population growth following exposures to these three algal species were noted, the rate was less than for the non-exposed control rotifer groups.In contrast, the remaining seven algal strains (A. tamarense ATHK, AT5-1, AT5-3, ATCI02, ATCI03; also Alexandrium sp1 and Alexandrium sp2) all have adverse effects on the rotifers. Dosing rotifers with respective algal cell densities of 2000 cells ml⁻¹ each, for Alexandrium sp1, Alexandrium sp2, and A. tamarense strains ATHK and ATCI03 showed mean lethal time (LT₅₀) on rotifer populations of 21, 28, 29, and 36h, respectively. The remaining three species (A. tamarense strains AT5-1, AT5-3, ATCI02) caused respective mean rotifer LT₅₀s of 56, 56, and 71 h, compared to 160 h for the unexposed “starved control” rotifers. Experiments to determine ingestion rates for the rotifers, based on changes in their Chlorophyll a content, showed that the rotifers could feed on A. lusitanicum, A. minutum and A. tamarense strain AT-6, but could graze to little or no extent upon algal cells of the other seven strains. The effects on rotifers exposed to different cell densities, fractions, and growth phases of A. tamarense algal culture were respectively compared. It was found that only the whole algal cells had lethal effects, with strongest impact being shown by the early exponential growth phase of A. tamarense. The results indicate that some toxic mechanism(s), other than PSP and present in whole algal cells, might be responsible for the adverse effects on the exposed rotifers.     

微囊化细胞培养过程的物质传递机理和细胞生长特性

综述了用于描述微囊化细胞培养过程中物质传递机理和细胞生长特性的数学模型,分析了这些模型在应用于微囊化细胞培养系统时所存在的问题,为建立能精确描述微囊化细胞培养过程中的物质传递机理和细胞生长特性的数学模型提供必要的参考,以有效推动微囊化技术在生物医学工程领域的应用。     

中国多孔菌二新记录种(英文)

在对黑龙江省东部和南部地区木腐菌调查中,发现两种多孔菌:红斑波氏菌(Postia lateritiaRenvall)和烟曲色干酪菌(Tyromyces fumidicepsG.F.Atk),均为中国新记录种。前者发现于宁安市地下森林公园内的松树倒木上,后者采集自虎林市七虎林林场内的阔叶树上。根据采集的材料对其进行了详细描述和显微结构绘图,并对相似种进行了讨论。     

Photosynthetic Characterization of the Plant Dicranopteris dichotoma Bernh. in a Rare Earth Elements Mine

In order to investigate the distribution of rare earth elements （REEs） in the natural hyperaccumulator fern Dicranopteris dichotoma Bernh. and to characterize this plant photosynthetically, concentrations of REEs in D. dichotoma from mines mining heavy and light REEs （HREEs and LREEs, respectively）, as well as in D. dichotoma from an area in which no mining occurred, in southern Jiangxi Province were determined using inductively coupled plasma-mass spectrometry. The REE concentrations in the lamina of D. dichotoma were in the order LREEs mine 〉 HREEs mine 〉 non-mining area. The maximum REE content in the lamina of D. dichotoma from the LREE mine was approximately 2 648 mg/kg dry weight. The photosynthetic activity of D. dichotoma from areas of HREE and LREE mines was improved by the presence of high concentrations of REEs in the lamina compared with D. dichotoma from the non-mining area. However, this enhancement varied according to the concentrations of the REEs, as well as their type. In addition, 77K fluorescence, electron transport rate, and chlorophyll-protein complex studies showed that the enhancement of the photosynthetic activity of D. dichotoma from HREE mines was mainly due to an increase in the chlorophyll-protein complex of the reaction center of photosystem （PS） Ⅰ, whereas the enhancement observed in D. dichotoma from LREE mines was due to an increase in the internal antennae chlorophyll-protein complex of PS Ⅱ and greater light energy distribution to the light-harvesting chlorophyll-protein complex of PS Ⅱ.     

Formation and Growth of Bryopsis hypnoides Lamouroux Regenerated from Its Protoplasts

Tissue culture, SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and spectra analysis were used for studying the aggregation mechanism of protoplasts from Bryopsis hypnoides Lamouroux and the discrepancy between the protoplast-regenerated plants and the wild type. The aggregation of protoplasts from B. hypnoides was observed in natural seawater and artificial seawater with different pH values, and the location and mechanism of the materials causing the aggregation were also studied. Results showed that the protoplasts could aggregate into some viable spheres in natural seawater and subsequently grow into mature individuals. Aggregation of the protoplasts depended exclusively upon the pH value (6-11), and the protoplasts aggregated best at pH 8-9. Some of the extruded protoplasts were separated into two parts by centrifugation: the pellet (PO) and the supernatant (PL). The PO could aggregate in artificial seawater (pH 8.3) but not in PL. No aggregation was found in PO cultured in natural seawater containing nigericin, which can dissipate the proton gradients across the membrane. These experiments suggest that the aggregation of protoplasts is proton-gradient dependent and the materials causing the aggregation were not in the vacuolar sap, but located on the surface or inside the organelles. Furthermore, the transfer of the materials across the membrane was similar to △pH-based translocation (△pH/TAT) pathway that occurs in the chloroplasts of higher plants and bacteria. Obvious discrepancies in both the total soluble proteins and the ratio of chlorophyll a to chlorophyll b between the regenerated B. hypnoides and the wild type were found, which may be related to the exchange of genetic material during aggregation of the organelles. In the process of development, diatom Amphora coffeaeformis Agardh attached to the protoplast aggregations, retarding their further development, and once they were removed, the aggregations immediately germinated, which showed that diatoms can affect the development of other algae.