A reappraisal of the Palaeopantopoda with description of a species from the Jurassic

The Devonian fossil Palaeoisopus appears, in the light of recent evidence from newly found specimens, to be much nearer extant pycnogonids than previously surmised. The fossil record of the Pycnogonida is extended to the Jurassic on the basis of a long overlooked Solenhofen example. Most of the specimens ascribed to the common Solenhofen Phalangites cannot be pycnogonids, but it is possible that we are dealing with a complex of superficially similar fossils. A revision of the classification of the fossil pycnogonids (Order Palaeopantopoda) is suggested in the light of this new material.     

Fatty acids decrease mitochondrial generation of reactive oxygen species at the reverse electron transport but increase it at the forward transport

Long-chain nonesterified (“free”) fatty acids (FFA) can affect the mitochondrial generation of reactive oxygen species (ROS) in two ways: (i) by depolarisation of the inner membrane due to the uncoupling effect and (ii) by partly blocking the respiratory chain. In the present work this dual effect was investigated in rat heart and liver mitochondria under conditions of forward and reverse electron transport. Under conditions of the forward electron transport, i.e. with pyruvate plus malate and with succinate (plus rotenone) as respiratory substrates, polyunsaturated fatty acid, arachidonic, and branched-chain saturated fatty acid, phytanic, increased ROS production in parallel with a partial inhibition of the electron transport in the respiratory chain, most likely at the level of complexes I and III. A linear correlation between stimulation of ROS production and inhibition of complex III was found for rat heart mitochondria. This effect on ROS production was further increased in glutathione-depleted mitochondria. Under conditions of the reverse electron transport, i.e. with succinate (without rotenone), unsaturated fatty acids, arachidonic and oleic, straight-chain saturated palmitic acid and branched-chain saturated phytanic acid strongly inhibited ROS production. This inhibition was partly abolished by the blocker of ATP/ADP transfer, carboxyatractyloside, thus indicating that this effect was related to uncoupling (protonophoric) action of fatty acids. It is concluded that in isolated rat heart and liver mitochondria functioning in the forward electron transport mode, unsaturated fatty acids and phytanic acid increase ROS generation by partly inhibiting the electron transport and, most likely, by changing membrane fluidity. Only under conditions of reverse electron transport, fatty acids decrease ROS generation due to their uncoupling action.     

Paläoökologische Rekonstruktion von Wirbeltieren: Möglichkeiten und Grenzen

The constraints on paleoecological analyses of fossil vertebrates are discussed using the example of Permo-Carboniferous amphibians. Paleoecological interpretations based on the study of the vertebrates as well as the fossil-bearing de-posit are generally inexact and possibly even inaccurate. Thus as many aspects as possible must be examined — the animal with all of its anatomical components and the fossil-bearing deposit with all available Information concerning sedimentology and taphonomy. Comparisons based on constructional morphology permit ecomorphological characterization of a fossil organism, with an optional band width for different ecological parameters. Individual parameters can be further re-fined through a search for evidence regarding the actual ecological band width, specifically in terms of diet and habitat. Reliable, broadly based paleoecological analyses can only be done for fossil occurrences that preserve many, more or less articulated specimens of vertebrates, and, even in those in-stances, only for more or less aquatic forms. This is particularly applicable for higher-level studies at the level of “population” or ecosystem. The study of temporally much averaged “populations” can provide data concerning age distribution for and growth-related ecological changes in a particular species. Studies of an ecosystem aim to reconstruct the structure and functions of that System through a reconstruction of the food web. On this basis, evaluation of the ecological role of the species in the context of paleocommunities is possible.     

Large-scale preparation of the homogeneous LolA lipoprotein complex and efficient in vitro transfer of lipoproteins to the outer membrane in a LolB-dependent manner

An ATP-binding cassette transporter LolCDE complex of Escherichia coli releases lipoproteins destined to the outer membrane from the inner membrane as a complex with a periplasmic chaperone, LolA. Interaction of the LolA-lipoprotein complex with an outer membrane receptor, LolB, then causes localization of lipoproteins to the outer membrane. As far as examined, formation of the LolA-lipoprotein complex strictly depends on ATP hydrolysis by the LolCDE complex in the presence of LolA. It has been speculated, based on crystallographic and biochemical observations, that LolA undergoes an ATP-dependent conformational change upon lipoprotein binding. Thus, preparation of a large amount of the LolA-lipoprotein complex is difficult. Moreover, lipoproteins bound to LolA are heterogeneous. We report here that the coexpression of LolA and outer membrane-specific lipoprotein Pal from a very efficient plasmid causes the unusual accumulation of the LolA-Pal complex in the periplasm. The complex was purified to homogeneity and shown to be a functional intermediate of the lipoprotein localization pathway. In vitro incorporation of Pal into outer membranes revealed that a single molecule of LolB catalyzes the incorporation of more than 100 molecules of Pal into outer membranes. Moreover, the LolB-dependent incorporation of Pal was not affected by excess-free LolA, indicating that LolB specifically interacts with liganded LolA. Finally, the LolB depletion caused the accumulation of a significant amount of Pal in the periplasm, thereby establishing the conditions for preparation of the homogeneous LolA-lipoprotein complex.     

贵州鼠尾草化学成分的研究

从贵州鼠尾草95%乙醇提取物分离得到8个化合物,通过理化性质及波谱方法分别鉴定为正三十三烷(1),十二烷酸十四烷酯(2),β-谷甾醇(3),胡萝卜苷(4),乌苏酸(5),2 a,3β-二羟基乌苏酸(6),白桦酸(7)和迷迭香酸(8)。以上化合物均首次从该植物中分离得到。     

中国大戟科一新归化种——硬毛巴豆

首次报道了大戟科(Euphorbiaceae)巴豆属硬毛巴豆(Croton hirtus L'Hér.)在中国的归化新记录,并提供该种的特征描述和形态图。凭证标本保存于中国科学院华南植物园标本馆(IBSC)。     

The hitchhiker's guide to the periplasm: Unexpected molecular interactions of polymyxin B1 in E. coli

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越冬代亚洲玉米螟成虫发生动态及其与温度关系初探——以通辽市开鲁县为例

为明确亚洲玉米螟越冬代成虫发生动态及其与温度的关系,于2007-2016年利用频振式杀虫灯结合当地气象数据进行系统调查与分析。结果表明,自然条件下内蒙古通辽地区越冬代玉米螟成虫始见期在6月初(6月5日左右),高峰期在6月下旬(6月26日左右),终见期为7月中旬(7月14日左右),整个成虫期有效温度累积范围在150.0℃~750.0℃之间,高峰期集中在350.0℃~450.0℃的范围内。总的来看,越冬代成虫始见期与高峰期与吉林省中部地区大体相同,终见期稍晚于吉林中部地区但早于黑龙江哈尔滨地区。通辽与吉林中部地区越冬代成虫期(均40 d左右)约比黑龙江哈尔滨地区短10 d。可见,各地越冬代玉米螟成虫发生期的早晚和持续时间长短因地而异,同一地区受年份间的气温变化其也会出现差异。     

艾叶多糖提取率影响因素分析及提取条件优化

艾叶是菊科(Compositae)植物艾(Artemisia argyi Lévl.et Vant.)的干燥叶,为常用中药材之一,药用历史悠久,具有苦燥辛散、理气血、温经脉、逐寒湿、止冷痛等功效,为重要的妇科用药,可用于治疗脘腹冷痛、经寒不调、宫冷不孕等证.此外,利用艾叶预防瘟疫已有悠久的历史.现代药理研究表明:艾叶是一种广谱抗菌抗病毒中药,对多种病毒和细菌有抑制和杀伤作用,对呼吸系统疾病以及心血管等慢性疾病有一定的防治作用[1-3].因此,将艾叶中的有效成分分别提取和纯化并加以分析以及功能检测,具有深远意义.     

麦红吸浆虫滞育习性研究

1986～1991年研究了麦红吸浆虫的滞育习性,提出了该由主动延长滞育和被动延长滞育的两种形式,探讨了土壤湿度、温度对延长滞育的影响,从体重、羽化率、卵胚数、死亡率等方面测定了延长滞育幼虫的生殖势能,文章最后讨论了麦红吸浆虫多峰羽化的特点和延长滞育的生物学意义。