应用计算机进行植物自动分类的初步研究

应用计算机进行植物自动分类的初步研究傅星卢汉清,罗曼丽（中国科学院沈阳应用生态研究所,１１００１５）（中国科学院自动化研究所,北京１０００８０）曹伟,于兴华（中国科学院沈阳应用生态研究所,１１００１５）ＰｒｅｌｉｍｉｎａｒｙＳｔｕｄｙｏｎＡｕｔｏｍａ...     

梭鱼幼鱼选择温度的研究

梭鱼幼鱼选择温度的研究张梅英岳玉环（中国医科大学实验动物部,沈阳１１０００１）（吉林农业大学动物科学系,长春１３０１１８）侯文礼（东北师范大学环境科学系,长春１３００２４）ＴｅｍｐｅｒａｔｕｒｅｓｅｌｅｃｔｉｏｎｆｏｒＬａｒｖａｏｆＬｉｚａｈａｅｍａ...     

中国蛋白质组学第三届学术大会在长春市召开

为了促进我国蛋白质组学的研究与发展,由中国生物化学与分子生物学会蛋白质组学专业委员会（筹）和中国人类蛋白质组组织（CNHUPO）（筹）主办,中国科学院长春应用化学研究所和北京蛋白质组研究中心承办的中国蛋白质组学第三届学术大会于2005年7月25—27日在长春市中国科学院长春应用化学研究所教育大厦举行。     

三江平原沼泽生态系统（疏干）演替对土壤动物的影响

三江平原沼泽生态系统（疏干）演替对土壤动物的影响孙帆,赵红音吕宪国,杨青（东北师范大学地理系,长春１３００２４）（中国科学院长春地理研究所,１３００２１）ＩｍｐａｃｔｏｆＳｗａｍｐＥｃｏｓｙｓｔｅｍＳｕｃｃｅｓｓｉｏｎｉｎＳａｎｊｉａｎｇＰｌａｉｎｏ...     

中国应用生态学研究的信息源：祝贺本刊创刊5周年和本所建所40周年

中国应用生态学研究的信息源──祝贺本刊创刊５周年和本所建所４０周年孙顺江,宋凤兰,李凤琴（中国科学院沈阳应用生态研究所《应用生态学报》编辑部,沈阳１１００１５）１引言《应用生态学报）｝是由中国生态学会和中国科学院沈阳应用生态研究所主办的、科学出版社出...     

沙地云杉种群稳定性研究

沙地云杉种群稳定性研究郑元润徐文铎（中国科学院植物研究所,北京１０００９３）（中国科学院沈阳应用生态研究所,１１００１５）ＳｔｕｄｙｏｎＰｏｐｕｌａｔｉｏｎＳｔａｂｉｌｉｔｙｏｆＰｉｃｅａｍｏｎｇｏｌｉｃａｏｎＳａｎｄｙＬａｎｄ．ＺｈｅｎｇＹｕａｎ...     

从“DIVERSITAS计划新方案”看生物多样性研究的发展趋势

从“ＤＩＶＥＲＳＩＴＡＳ计划新方案”看生物多样性研究的发展趋势赵士洞（中国科学院自然资源综合考察委员会,北京１００１０１））郝占庆（中国科学院沈阳应用生态研究所,沈阳１１００１５）国际生物多样性合作研究计划“ＤＩＶＥＲＳＩＴＡＳ”,是目前唯一的致力...     

沙地云杉小树高生长与环境条件关系的数量化模型

沙地云杉小树高生长与环境条件关系的数量化模型郑元润徐文铎（中国科学院植物研究所,北京１０００９３）（中国科学院沈阳应用生态研究所,１１００１５）ＴｈｅＭｏｄｅｌｓｏｆＲｅｌａｔｉｏｎｓｈｉｐｂｅｔｗｅｅｎＨｅｉｇｈｔＧｒｏｗｔｈｏｆＰｉｃｅａｍｏｎｇ...     

土壤—植物根际磷的生物有效性研究

土壤－植物根际磷的生物有效性研究李法云高子勤（辽宁大学生物系,沈阳１１００３６）（中国科学院沈阳应用生态研究所,１１００１５）ＳｔｕｄｙｏｆＰｈｏｓｐｈｏｒｕｓＢｉｏｌｏｇｉｃａｌＡｖａｉｌａｂｉｌｉｔｙｉｎｔｈｅＳｏｉｌ＿ｐｌａｎｔＲｈｉｚｏｓｐｈ...     

植食性昆虫产卵的化学生态学

植食性昆虫产卵的化学生态学张庆贺,姬兰柱（林业部森林病虫害防治总站沈阳１１００３１）（中国科学院沈阳应用生态研究所,１１００１５）ＣｈｅｍｉｃａｌＥｃｏｌｏｇｙｏｆＯｖｉｐｅｓｉｔｉｏｎｏｆＨｅｒｂｉｖｏｒｏｕｓＩｎｓｅｔｔｓ．￥ＺｈａｎｇＱｉｎｇｈ...     

Aerobic purification of N5,N10-methylenetetrahydromethanopterin dehydrogenase, separated from N5,N10-methylenetetrahydromethanopterin cyclohydrolase, from Methanobacterium thermoautotrophicum strain Marburg

The N5,N10-methylenetetrahydromethanopterin dehydrogenase from Methanobacterium thermoautotrophicum strain Marburg has been purified with reasonable yield and much higher specific activity than previously reported. For the first time it has been shown that both N5,N10-methylenetetrahydromethanopterin dehydrogenase and N5,N10-methenyltetrahydromethanopterin cyclohydrolase activities were stable under air and could be purified using aerobic operations. The dehydrogenase activity from Methanobacterium thermoautotrophicum Marburg was stable in phosphate buffer with or without glycerol or ammonium sulfate under both aerobic and anaerobic conditions. However, the presence of either 2-mercaptoethanol or dithiothreitol in the enzyme solution destroyed the enzyme activity during both aerobic and anaerobic incubations. Dehydrogenase was purified 62-fold using Phenyl-Sepharose and DEAE-Sephadex chromatography in succession under air. Both of these chromatographic methods separated dehydrogenase activity from N5,N10-methenyltetrahydromethanopterin cyclohydrolase; DEAE-Sephadex provided the best separation. Phenyl-Sepharose chromatography of the supernatant of cell extracts containing ammonium sulfate at 60% of saturation provided a 4.7-fold purification and 98% recovery of cyclohydrolase; this result established the air stability of N5,N10-methenyltetrahydromethanopterin cyclohydrolase from Methanobacterium thermoautotrophicum Marburg.     

Amine inversion in proteins. A 13C-NMR study of proton exchange and nitrogen inversion rates in N epsilon,N epsilon,N alpha,N alpha-[13C]tetramethyllysine,N epsilon,N epsilon,N alpha,N alpha-[13C]tetramethyllysine methyl ester, and reductively methylated concanavalin A

Exchange rates were calculated as a function of pH from line widths of methylamine resonances in 13C-NMR spectra of N epsilon,N epsilon,N alpha,N alpha-[13C]tetramethyllysine (TML) and N epsilon,N epsilon,N alpha,N alpha-tetramethyllysine methyl ester (TMLME). The pH dependence of the dimethyl alpha-amine exchange rate could be adequately described by assuming base-catalyzed chemical exchange between two diastereotopic methyl populations related by nitrogen inversion. Deprotonation of the alpha-amine was assumed to occur by proton transfer to (1) OH-, (2) water, (3) a deprotonated amine or (4) RCO2-. Microscopic rate constants characterizing each of these transfer processes (k1, k2, k3 and k4, respectively) were determined by fitting the rates calculated from line width analysis to a steady-state kinetic model. Using this procedure it was determined that for both TML and TMLME k2 approximately equal to 1-10 M-1 s-1, k3 approximately equal to 10(6) M-1 s-1 and ki, the rate constant for nitrogen inversion was about 10(8)-10(9) s-1. Upper limits of 10(12) and 10(3) M-1 s-1 could be determined for k1 and k4, respectively. A similar kinetic analysis was used to explain pH-dependent line-broadening effects observed for the N-terminal dimethylalanyl resonance in 13C-NMR spectra of concanavalin A, reductively methylated using 90% [13C]formaldehyde. From exchange data below pH 4 it could be determined that amine inversion was limited by the proton transfer rate to the solvent, with a rate constant estimated at 20 M-1 s-1. Above pH 4, exchange was limited by proton transfer to other titrating groups in the protein structure. Based upon their proximity, the carboxylate side chains of Asp-2 and Asp-218 appear to be likely candidates. The apparent first-order microscopic rate constant characterizing proton transfer to these groups was estimated to be about 1 X 10(4) s-1. Rate constants characterizing nitrogen inversion (ki), proton transfer to OH- (k1) and proton transfer to the solvent (k2) were estimated to be of the same order of magnitude as those determined for the model compounds. On the basis of our results, it is proposed that chemical exchange processes associated with base-catalyzed nitrogen inversion may contribute to 15N or 13C spin-lattice relaxation times in reductively methylated peptides or proteins.     

Interaction of N,N,N-trialkylammonioundecahydro-closo-dodecaborates with dipalmitoyl phosphatidylcholine liposomes

N,N,N-Trialkylammonioundecahydrododecaborates (1-), a novel class of compounds of interest for use as anions in ionic liquids, interact with DPPC liposomes. Increasing compound concentration causes an increasing negative ζ potential. Dissociation constants demonstrate that the binding capacity increases strongly with longer chain length. N,N,N-Trialkylammonioundecahydrododecaborates with longer alkyl chains show a detergent-like behavior: the compounds incorporate into the liposome membrane and differential scanning calorimetric experiment show already low concentrations cause a complete disappearance of the peak representing the gel-to-liquid crystalline phase transition. In contrast, compounds with shorter alkyl chains only interact with the headgroups of the lipids. Investigations by means of cryo-TEM reveal that all derivatives induce significant morphological changes of the liposomes. N,N,N-Trialkylammonioundecahydrododecaborates with short alkyl chains produce large bilayer sheets, whereas those with longer alkyl chains tend to induce the formation of open or multi-layered liposomes. We propose that the binding of N,N,N-trialkylammonioundecahydrododecaborates is mainly due to electrostatic interactions between the doubly negatively charged cluster unit and the positively charged choline headgroup; the positively charged ammonium group might be in contact with the deeper-lying negatively charged phosphate. For N,N,N-trialkylammonioundecahydrododecaborates with longer alkyl chains hydrophobic interactions with the non-polar hydrocarbon part of the membrane constitute an additional important driving force for the association of the compounds to the lipid bilayer.     

A synthesis of N6,N6,N6-trimethyl-L-lysine dioxalate in gram amounts

A procedure is described for the synthesis of crystalline N6,N6,N6-trimethyl-L-lysine dioxalate in gram amounts starting from the commercially available N2-tert-butoxycarbonyl-N6-benzyloxycarbonyl-L-lysine, which is reacted with methyl iodide in methanol in the presence of potassium hydrogen carbonate after deprotection of the side-chain amino group by catalytic hydrogenation. The work-up involves only filtrations and evaporations.     

N deposition, N transformation and N leaching in acid forest soils

Nitrogen deposition, mineralisation, uptake and leaching were measured on a monthly basis in the field during 2 years in six forested stands on acidic soils under mountainous climate. Studies were conducted in three Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] plantations (D20: 20 year; D40: 40 yr; D60: 60 yr) on abandoned croplands in the Beaujolais Mounts; and two spruce (Picea abies Karst.) plantations (S45: 45 yr; S90: 90 yr) and an old beech (Fagus sylvatica L.) stand (B150: 150 yr) on ancient forest soils in a small catchment in the Vosges Mountains. N deposition in throughfall varied between 7–8 kg ha^–1 year^–1 (D20, B150, S45) and 15–21 kg ha^–1 yr^–1 (S90, D40, D60). N in annual litterfall varied between 20–29 kg ha^–1 (D40, D60, S90), and 36–43 kg ha^–1 (D20, S45, B150). N leaching below root depth varied among stands within a much larger range, between 1–9 kg ha^–1 yr^–1 (B150, S45, D60) and 28–66 kg ha^–1 yr^–1 (D40, S90, D20), with no simple relationship with N deposition, or N deposition minus N storage in stand biomass. N mineralisation was between 57–121 kg ha^–1 yr^–1 (S45, D40, S90) and between 176–209 kg ha^–1 yr^–1 in (B150, D60 and D20). The amounts of nitrogen annually mineralised and nitrified were positively related. Neither general soil parameters, such as pH, soil type, base saturation and C:N ratio, nor deposition in throughfall or litterfall were simply related to the intensity of mineralisation and/or nitrification. When root uptake was not allowed, nitrate leaching increased by 11 kg ha^–1 yr^–1 at S45, 36 kg ha^–1 yr^–1 at S90 and between 69 and 91 kg ha^–1 yr^–1 at D20, D40, B150 and D60, in relation to the nitrification rates of each plot. From this data set and recent data from the literature, we suggest that: high nitrification and nitrate leaching in Douglas-fir soils was likely related to the former agricultural land use. High nitrification rate but very low nitrate leaching in the old beech soil was related to intense recycling of mineralised N by beech roots. Medium nitrification and nitrate leaching in the old spruce stand was related to the average level of N deposition and to the deposition and declining health of the stand. Very low nitrification and N leaching in the young spruce stand were considered representative of fast growing spruce plantations receiving low N deposition on acidic soils of ancient coniferous forests. Consequently, we suggest that past land use and fine root cycling (which is dependent on to tree species and health) should be taken into account to explain the variability in the relation between N deposition and leaching in forests.     

Electrosprayed polyelectrolyte complexes between mucoadhesive N,N,N,-trimethylchitosan-homocysteine thiolactone and alginate/carrageenan for camptothecin delivery

Novel hydrogel polyelectrolyte complexes (PECs) between the N,N,N,-trimethylchitosan-homocysteine thiolactone (TM-HT-chitosan) and two anionic polymers were investigated. The particles of pure thiolated chitosan and its PECs with alginate and carrageenan were fabricated using the electrospray ionization technique. The hydrogel PEC particles were characterized by scanning electron microscopy, dynamic light scattering, Fourier transform infrared microscopy, thermogravimetric analysis, encapsulation efficiency (EE), mucoadhesive property and in vitro drug release behavior. TM-HT-chitosan/alginate particles could be loaded with camptothecin (CPT), employed as a model anti-cancer drug, at an over 70% EE, and revealed both a reduced burst effect and a prolonged release of CPT over 3 days. The resultant TM-HT-chitosan/alginate PEC particles displayed a 5.60-, 1.86- and 1.55-fold stronger mucoadhesive property compared to that of the unmodified chitosan/alginate PEC at pH 1.2, 4.0 and 6.4, respectively, and this was not affected by the CPT loading level.