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松辽盆地阿尔必期微体浮游植物新属种 总被引:4,自引:3,他引:1
该文描述了松辽盆地中白垩世阿尔必期泉头组三段的微体浮游植物化石1新属7新种,隶属于微咸水沟鞭藻类2属5新种(含4新亚种),淡水绿藻1属1种和疑源类1新属1新种。并对沟鞭藻 Ngktericysta Bint,1986进行了修订。 相似文献
3.
1 前言 从外地引进寄蝇或人工助长当地寄蝇种类防治农林害虫,是有效的生防手段之一,国外已有很多成功的报道。King等(1981)在路易斯安娜州蔗田中人工大量释放螟利索寄蝇(Lixophaga diatraeae)成虫防治第1代小蔗杆草螟(Diatraea saccharalis),不同地区的寄生率分别达到4.1、8.7和35.7%;由于降低了农药的使用量,奇痣窄径茧蜂(Agathis stigmatera)的自然寄生率也相应提高,很好地控制了蔗田害虫的发生。在寄蝇的田间释放技术方面,国外还没有详细的报道。在我国,利用寄蝇防治害虫的工作也是刚刚起步,很多具体问题有待于进一步研究。 相似文献
4.
黑曲霉糖化酶高产和低产菌株糖化酶基因调控区的克隆及其分析比较 总被引:8,自引:1,他引:7
以PCR合成的糖化酶高产菌株黑曲霉(Asp. Niger)T21糖化酶基因5’近端非编码区588bp(EcoRI-BamHI)的序列为探针,从T21染色体DNA中克隆到近2.0kb的糖化酶基因5’端非编码区序列,并以此序列为探针从糖化酶低产菌株黑曲霉3.795(T21的诱变出发株)的染色体DNA中克隆到1.5kb的糖化酶基因5’端非编码区序列。该二序列的分析测定结果表明,其结构特征与文献报道的黑曲霉糖化酶基因5’端非编码区的基本一致,被称为“核心启动子”(Core promoter)的TATAAAT框及GCAAT框,分别在翻译起始点的-109bp及-178bp处。此外,在曲霉amdS,amyB基因中已发现有调控功能的CCAAT序列存在于-449bp和-799bp处。高产和低产菌株糖化酶基因5’端非编码区序列的分析比较结果表明,有9个部位的碱基发生了变化。此实验结果为进一步研究黑曲霉糖化酶基因在转录水平上的调控规律打下了基础。 相似文献
5.
Geneticdivergenceanalysiswasconductedbasedonperformanceof12quantitativetraitsin85sunflowerinbredlines,tostudyitseffectivenessinpredictingyieldheterosisofthe72hybridsfromthem.Resultsshowedthatlinearregressionmodelfittherelationshipbetweenheterosisofseedoilcontentandgeneticdistance,andquadraticregressionequationtherelationshipbetweengrainyieldheterosisandgeneticdistance,whichcanbeusedinpredictingheterosisfromtheparentperformances.Clusteranalysiswaseffectivetocertainextent,butitsutilizationshouldbelimited.Grainyieldandoilcontentcanbeimprovedsimutaneouslyaccordingtotherelationsbetweengeneticdivergenceandtheheterosisofthesetwotraits. 相似文献
6.
黑龙江宁安盆地穆棱组及其孢粉型组合新发现 总被引:8,自引:2,他引:6
黑龙江宁安盆地是一个具有油气勘探远景的中小型盆地,主要目的层为下白垩统。新发现了一套相当于邻区穆棱组的地层,孢粉化石十分丰富,建立了5个孢粉组合带,通过对两口石油探井生物地层的研究,建立了该舅地新的地层层序,并对穆棱组的时代和沉积环境进行了讨论。 相似文献
7.
Xiaoming Li Xiaopeng Duan Jiawei Qiao Shilin Li Yunhao Cai Jianqi Zhang Yuan Zhang Xiaotao Hao Yanming Sun 《Liver Transplantation》2023,13(1):2203044
The power conversion efficiencies (PCEs) of all-polymer solar cells (all-PSCs) have already exceeded 17%. However, the limited absorption range of an all-polymer system results in significantly reduced short-circuit current density (Jsc), which eventually influences the PCE improvement. To broaden the light absorption of polymer acceptors, herein, benzotriazole is introduced in the core unit of small molecule acceptors and thus two narrow-bandgap polymer acceptors named PTz-BO and PTz-C11 featuring the same molecular backbone and different side-chain length are synthesized. Compared with PTz-C11, the PTz-BO based-all PSCs deliver a slightly reduced Jsc, a large open-circuit voltage (Voc) and a low voltage loss below 0.50 V. Moreover, ternary all-PSCs are constructed by introducing PTz-C11 as a guest component. Benefiting from the reduced recombination, improved exciton generation and dissociation, and balanced charge transport, a high efficiency of 16.58% is obtained for the ternary all-PSCs, with a high Jsc over 25 mA cm−2 without sacrificing the Voc. Such result represents the highest efficiency reported for benzotriazole-based all-PSCs in the literature thus far. This work demonstrates the great potential of benzotriazole for the synthesis of efficient narrow-bandgap polymer acceptors. 相似文献
8.
Zelong Miao Chao Xiong Xiaolong Cao Tisheng Shan Qiao Jin Haobo Jiang 《Insect Science》2023,30(2):338-350
Serine esterases (SEs) are hydrolases that catalyze the conversion of carboxylic esters into acids and alcohols. Lipases and carboxylesterases constitute two major groups of SEs. Although over a hundred of insect genomes are known, systematic identification and classification of SEs are rarely performed, likely due to large size and complex composition of the gene family in each species. Considering their key roles in lipid metabolism and other physiological processes, we have categorized 144 M. sexta SEs and SE homologs (SEHs), 114 of which contain a motif of GXSXG. Multiple sequence alignment and phylogenetic tree analysis have revealed 39 neutral lipases (NLs), 3 neutral lipase homologs (NLHs), 11 acidic lipases (ALs), 3 acidic lipase homologs (ALHs), a lipase-3, a triglyceride lipase, a monoglyceride lipase, a hormone-sensitive lipase, and a GDSL lipase. Eighty-three carboxylesterase genes encode 29 α-esterases (AEs), 12 AEHs (e.g., SEH4-1–3), 20 feruloyl esterases (FEs), 2 FEHs, 2 β-esterases (BEs), 2 integument esterases (IEs), 1 IEH, 4 juvenile hormone esterases, 2 acetylcholinesterases, gliotactin, 6 neuroligins, neurotactin, and an uncharacteristic esterase homolog. In addition to these GXSXG proteins, we have identified 26 phospholipases and 13 thioesterases. Expression profiling of these genes in specific tissues and stages has provided insights into their functions including digestion, detoxification, hormone processing, neurotransmission, reproduction, and developmental regulation. In summary, we have established a framework of information on SEs and related proteins in M. sexta to stimulate their research in the model species and comparative investigations in agricultural pests or disease vectors. 相似文献
9.
Tiecheng Qiao Robert Witkowski Robin Henderson G. McLendon 《Journal of biological inorganic chemistry》1996,1(5):432-438
The kinetics of methemoglobin reduction by cytochrome b
5 has been studied by stopped-flow and saturation transfer NMR. A forward rate constant k
f = 2.44×104 M–1 s–1 and a reverse rate constant k
b = 540 M–1s–1 have been observed at 10 mm, pH 6.20, 25 °C. The ratio k
f/k
b = k
eq = 43.6 is in good agreement with the equilibrium constant calculated from the electrochemical potential between cyt b
5 and methemoglobin. A bimolecular collisional mechanism is proposed for the electron transfer from cyt b
5 to methemoglobin based on the kinetic data analysis. The dependence of the rate constants on ionic strengths supports such
collisional mechanism. It is also found that the reaction rate strongly depends on the conformations of methemoglobin.
Received: 20 February 1996 / Accepted: 4 June 1996 相似文献
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