CO2浓度倍增对小麦叶绿体超微结构、超分子结构及光谱特性的影响

超薄切片及冰冻撕裂电镜观察、吸收光谱及 77K低温荧光发射光谱的测定结果表明 :CO2 浓度倍增对小麦(TriticumaestivumL .)叶绿体的超微、超分子结构及光谱特性的影响均为正效应。具体反映在 :(1)小麦叶绿体中除了比对照积累有较多的淀粉粒外 ,其基粒和基质类囊体膜发育较好 ;(2 )叶绿体的光合膜系 ,无论是垛叠和非垛叠膜区 ,其镶嵌于内质膜撕裂面 (EFs和EFu)及原生质膜撕裂面 (PFs和PFu)的功能蛋白粒均比其对照的发育良好 ,尤其PFs与EFs面较为突出 ,即它们除了所含蛋白粒的密度较大外 ,在EFs面上有时还呈现出密集有序的阵列结构 ;(3)叶绿体整个吸收谱带 ,尤其红区和蓝区的主峰均较其对照有较大的光吸收 ,表明对光能的捕获能力明显高于对照 ;(4)无论是以 4 36nm还是以 4 80nm波长激发的 ,其叶绿体的F684/F73 3 (PSⅡ /PSⅠ )的比值均较对照的高 ,表明CO2 浓度倍增条件下生长的小麦叶片叶绿体的PSⅡ相对荧光强度有所增强 ,这与叶绿体的超微、超分子结构及吸收光谱的测定结果相一致。以上结果可为小麦在高CO2 浓度下增产提供理论依据。     

莲子光下萌发过程中光合膜超分子结构与27kD多肽变化

冰冻撕裂电镜观察及膜多肽组分的研究结果表明,随着莲子在光下萌发时间的延长,莲(Nelumbonucifera Gaertn.)胚芽叶的叶绿体光合膜的超分子结构发育与膜多肽组分中的27kD多肽含量变化具有明显的相关性:1.萌发2d后,胚芽叶的叶绿体巨基位变成解垛叠状态,其光合膜的超分子结构只呈现解垛叠类囊体区外质膜撕裂面(EF)和解垛叠类囊体的原生质膜撕裂面(PF)两个面;膜组分中主要是30kD多肽,而27kD多肽含量甚微。2.萌发4d后,光合膜从解垛叠开始转变成小基粒垛,垛叠区类囊体外质膜撕裂面(EFs)和垛叠类囊体的原生质膜撕裂面(PFs)开始发育;27kD多肽含量开始增加,30kD多肽含量开始减少。3.萌发6～8d后,光合膜明显分化出非垛叠膜区,非垛叠类囊体的外质膜撕裂面(EFu)和非垛叠类囊体的原生质膜撕裂面(PFu)开始呈现,EFs和PFs功能蛋白颗粒逐渐增多;27kD多肽逐渐增加,30kD多肽逐渐减少。4.萌发10～12d后,光合膜垛叠和非垛叠膜区分化完善,排列有序,EFs、PFs、EFu和PFu面功能蛋白颗粒的密度、大小、分布等超分子构象发育正常;27kD多肽更加增多,30kD多肽几乎消失。表明其超分子结构的发育动态既与其超微结构变化相一致,又与27kD多肽含量变化相吻合,却与一般高等植物的叶绿体发育相反,可为显示莲在被子植物系统演化中的独特地位提     

光周期对光敏核不育水稻叶绿体类囊体膜超分子结构的影响

通过冰冻撕裂叶绿体类囊体膜电镜术的研究,在超分子水平上揭示出长日照（ＬＤ）与短日照（ＳＤ）对突变型光敏核雄性不育水稻农垦５８Ｓ及其野生型农垦５８ 倒二叶叶绿体类囊体膜的形成有不同的影响。农垦５８－ＳＤ 和农垦５８－ＬＤ差别不明显;而农垦５８Ｓ－ＳＤ和农垦５８Ｓ－ＬＤ之间出现较明显的差异：（１）农垦５８Ｓ－ＳＤ 叶绿体类囊体膜的垛叠和非垛叠膜区的４ 个冰冻撕裂膜小面呈现的功能蛋白粒的密度、大小及构象分布与其对照农垦５８－ＳＤ 和农垦５８－ＬＤ 类似,均属正常的超分子结构类型。（２）农垦５８Ｓ－ＳＤ叶绿体垛叠类囊体膜区的外质撕裂面（ＥＦｓ）功能蛋白粒的密度比５８Ｓ－ＬＤ的大,且在有的垛叠膜区呈现出类晶格状的规则排列。（３）农垦５８Ｓ－ＬＤ 叶绿体非垛叠膜区的原生质撕裂面（ＰＦｕ）和外质撕裂面（ＥＦｕ）出现频率较低,往往在基粒的边缘膜或末端中能找到,且分布于膜上的功能蛋白粒的密度较小。有的叶绿体ＥＦｕ、ＰＦｕ、ＥＦｓ和垛叠膜区原生质撕裂面（ＰＦｓ）功能蛋白粒极少或丧失,表明类囊体膜受到严重损伤     

CO2和O3浓度倍增及其交互作用对大豆叶绿体超微结构的影响

应用透射电镜观察了模拟大气CO2和O3浓度倍增及其交互作用(开顶箱法)对大豆叶肉细胞叶绿体超微结构的影响。结果表明,CO2浓度倍增促进了大豆叶绿体的发育,内含淀粉粒积累明显增多、体积增大;叶绿体被膜保持完好;叶绿体基粒片层排列整齐,而O3浓度倍增抑制了叶绿体内淀粉粒的累积,并导致叶绿体被膜破碎,片层解体,严重地破坏了叶绿体的结构和功能CO2和O3浓度倍增的交互作用对叶绿体超微结构有不同程度的破坏,但二者浓度呈梯度增加对叶绿体的损害作用要大于二者浓度持续倍增对叶绿体的影响,进一步表明CO2正效应对O3负效应的补偿作用。     

生长期间的光强度对小麦光谱特性的影响

在强光(20 klx)下生长的小麦,其叶片和叶绿体的低温(77K)荧光发射强度明显高于在弱光(2 klx)下生长的小麦。同时,前者的PSⅡ的相对荧光产量与PSⅠ的相对荧光产量的比值也高,表明增加光强度有利于PSⅡ的发育。此外。在强光下生长的小麦具有更高的PSⅡ活性和原初光能转化效率。在等量叶绿素的情况下,生长在弱光下的小麦,其叶绿体在吸收光谱上的两个特异吸收带都有较高的吸收值,表明它们比在强光下生长的小麦叶绿体含有较多的光合膜,从而有更大截获光能的面积。     

玉米类囊体膜的超分子结构及LHCP在个体发育中的变化

对玉米(Zea mays)营养生长期中的下位叶(第5叶)和生殖生长时期的中位叶(果穗叶)和上位叶(顶生叶)的成熟叶片的冰冻撕裂电镜观察,发现叶绿体类囊体膜所有撕裂面上各种功能蛋白颗粒的密度均以果穗叶中的最大,依次是顶生叶和第5叶的。以果穗叶与顶生叶相比,其类囊体膜中包含有绝大多数 LHCP 的 EFs 颗粒增加28%;包含有 PSI 反应中心与LHCP 相结合的 PFu 颗粒增加20%;包含有 PSII 反应中心与 LHCP 相结合的 EFs 颗粒增加19%。这一超分子结构的电镜观察结果与其 SDS-聚丙烯酰胺梯度凝胶板电泳解析的结果相一致。即 SDS-聚丙烯酰胺梯度凝胶板电泳解析的色素带上,同样是果穗叶类囊体膜上呈现的21kD(LHCP Ⅰ)和25 kD(LHCPⅡ)多肽的色素带相应地也比顶生叶的加宽,表明果穗叶叶绿体类囊体膜上镶嵌的叶绿素 a/b 蛋白复合体等比顶生叶的显著地增多,这有利于果穗叶光合作用中光能的吸收、传递、分配和转化。     

不同光质下生长的满江红叶绿体和共生者满江红鱼腥藻的吸收光谱和荧光光谱的研究

测定了不同光质下培养的满江红的叶绿体和满江红鱼腥藻的吸收光谱和荧光光谱。吸收光谱表明:对于前者叶绿体,红光和蓝光比白光和绿光更有利于Chl a的形成。对于后者光对其色素的影响比叶绿体更为敏感。在白光下其胆藻素含量最高,在红光下P_(330)含量最高,依次为蓝光、白光、绿光;而类胡萝卜素相对稳定。荧光发射光谱表明:红光下培养的满江红的叶绿体PS Ⅱ荧光发射最强,蓝光、白光、绿光依次减弱。这与我们在电镜下观察到叶绿体膜垛叠的结果是一致的。而在满江红鱼腥藻中,不同光质下的差异与叶绿体不同。从荧光光谱和类囊体膜垛叠的分析表明,我们从另一方面支持了Arntzen等(1977)关于系统Ⅱ颗粒主要分布在基粒膜上的观点。     

大气CO2浓度倍增和施氮对冬小麦光合及叶绿素荧光特性的影响

采用开顶式气室,通过土培盆栽实验研究了不同大气CO2浓度(背景空气浓度375μmol·mol-1和倍增浓度750μmol·mol-1)和氮素水平(不施氮和施氮0.25 g/kg)下两个冬小麦品种(小偃6号和小偃22)主要生育期(拔节、孕穗、扬花、灌浆期)叶片叶绿素含量和荧光动力学参数的变化.结果显示,与背景CO2浓度相比,在不施氮条件下大气CO2浓度倍增处理的小麦叶片出现明显的光合下调现象,而施氮时变化不明显;同时,CO2浓度倍增后小麦各主要生育期叶片叶绿素含量均有不同程度地下降,荧光参数初始荧光(F0)值明显提高,最大荧光(Fm)、可变荧光(Fv)、最大光能转换效率(Fv/Fm)和PSⅡ潜在活性(Fv/F0)值均显著降低.施氮可提高冬小麦各个时期叶片叶绿素含量、Fm、Fv、和Fv/F0值,降低F0值;不施氮条件下,大气CO2浓度倍增对冬小麦各主要生育时期叶绿素含量和荧光参数的影响明显,而施氮后影响微弱.研究表明,大气CO2浓度升高对冬小麦光合速率、叶绿素含量和光系统Ⅱ(PSⅡ)的光合电子传递和潜在活性具有一定抑制作用,通过施氮可以有效地缓解其负面效应.     

叶绿体膜的结构与功能 Ⅺ.亚麻酸对小麦叶绿体膜结构、吸收光谱和荧光光谱的影响以及镁离子的调节作用

研究不同浓度的亚麻酸对小麦叶绿体膜结构、吸收光谱和荧光光谱的影响。观察到亚麻酸对叶绿体结构有显著的影响,并可提高叶绿体囊状体膜在蓝区和红区的吸收峰值,以及 F_(685)和 F_(738)的相对荧光产量。这些影响随着亚麻酸浓度的提高而加剧。此外,观察到 MgCl_2能够部分逆转亚麻酸所引起的叶绿体膜结构的变化,并能部分恢复囊状体膜吸收光谱的变化;同时,MgCl_2可进一步提高亚麻酸处理后叶绿体的 F_(685)相对荧光产量,但 F_(738)的相对荧光产量几乎不受影响。     

氮素水平对小麦幼苗叶绿体色素蛋白复合体含量的影响

在水培条件下,研究了不同氮素水平对小麦幼苗叶绿体色素、色素蛋白复合体含量及其光谱特征的影响。结果显示:(1)氮素水平较低时PSⅡ捕光色素蛋白复合体LHCⅡ在24~30 kD范围内的蛋白含量降低,不供氮时,色素蛋白复合体含量最低,而高分子量区域的蛋白组分相对较为稳定,说明氮素水平影响PSⅡ的多肽组分,而对PSⅠ多肽组分的影响相对较小。(2)室温吸收光谱分析表明,氮素水平较低时结合态色素的含量及比例发生改变,影响植物对光的吸收能力;荧光激发及发射光谱的峰值均随氮素浓度的升高而升高,说明增加施氮量时,叶绿体类囊体中受激发的色素分子数目增加,荧光强度也随之增大;叶绿体蛋白含量在16.86 mg.L-1氮素浓度时最大。     

Spectroscopic Characterization of a VO<Superscript>2+</Superscript> Complex of Oxodiacetic Acid and its Bioactivity on Osteoblast-like Cells in Culture

The oxovanadium(IV) complex of oxodiacetic acid (H₂oda) of stoichiometry [VO(oda)(H₂O)₂], which presents an unprecedented tridentate OOO coordination, was thoroughly characterized by infrared, Raman, electronic, and electron paramagnetic resonance spectroscopies. The biological activity of the complex on the cell proliferation and differentiation was tested on osteoblast-like cells (MC3T3E1 osteoblastic mouse calvaria-derived cells and UMR106 rat osteosarcoma-derived cells) in culture. The complex caused inhibition of cellular proliferation in both osteoblast-like cells in culture, but the cytotoxicity was stronger in the normal (MC3T3E1) than in the tumoral (UMR106) osteoblasts. The effect of the complex in cell differentiation was tested through the specific activity of alkaline phosphatase of the UMR106 cells because they expressed a high activity of this enzyme. What occurs with other vanadium compounds [VO(oda)(H₂O)₂] is an inhibitory agent of osteoblast differentiation.     

Characterization of complexes formed between [Me2Sn(IV)]2+ and carboxymethylcelluloses

Complexes formed between carboxymethylcellulose (CMC) and the [Me(2)Sn(IV)]2+ cation have been prepared in the solid state and characterized by FTIR and M?ssbauer spectroscopy. The complexes contained CMC with varying molar weight and degree of carboxylation, and the complexes were isolated both from acidic and from neutral solutions at varying metal-to-ligand ratios. The characteristic vibration bands of the ligands were identified from their pH-dependent FTIR spectra. In the organotin(IV) complexes obtained at pH approximately 2, the -COO- moieties were found to be coordinated in a monodentate manner, and the band characteristic of the protonated (unbound) -COO- group(s) was also identified. The broad -OH band can be interpreted as the sum of the contributions of the alcoholic -OH groups of the anhydroglucose units and the mixed organotin aqua complexes. In complexes obtained at pH approximately 7, the broad -OH band significantly sharpens, which is probably due to the metal-ion induced deprotonation and subsequent coordination of the alcoholic -OH groups. At the same time, -COO- groups are also involved in the coordination of the metal ions, resulting in a complicated network that forms through inter- and intramolecular bridges. Quadrupole splitting (/Delta(exp)/) values observed by M?ssbauer spectroscopy revealed that the valence state of tin is four in all of the complexes. The /Delta(exp)/ values were compared with the calculated ones, obtained from the pqs theory. From these data, trigonal bipyramidal (Tbp) and octahedral (Oh) geometries have been suggested for the complexes obtained. It has also been concluded that the structure of the complexes prepared depends mainly on the pH of the solution, and it is relatively insensitive to the other parameters, like molar mass or degree of carboxylation of the ligand, or the metal-to-ligand ratio in the reaction mixture.     

Evaluation of models capacity to predict size spectra parameters in ecosystems under stress

Size spectra are important indicators of biomass distribution, for fundamental understanding as well as for application in management. While many size spectra models have been developed, it is unclear how response to stress varies across models and in comparison to data. In the present study, we therefor collected papers on empirical size spectra in stressed aquatic ecosystems and compared the results to theoretical models’ predictions from literature. A general decrease of the slope, as suggested by most of the studied models, is supported by the data found. The investigated empirical studies revealed a strong trend for the slope: 40 out of 57 studies reported a decrease with stress. Deviations from the linear model increased in 10 out of 20 cases and the intercept became larger in 25 out of 43 cases. The data concerning specific impact drivers is generally consistent and supportive of current expert opinions. Our results support that an integration of deviation from the linear model and intercept in the size spectra models could provide better coupling between modeling and field surveys for some stressors.     

Quantum chemical insight on vibration spectra of silica systems

A set of silicate ions and corresponding lithium salts have been quantum chemically (QC) simulated in a “free molecule” approach. The infrared (IR), inelastic neutron scattering (INS), and Raman spectra have been simulated and fitted to the experimentally registered ones. The complete assignment of the vibrational bands along with the intensities and potential energy distribution has been performed. The applicability of the traditionally used quasimolecule Si–O–Si model to the interpretation of bands near 440–480 cm^? 1 and so-called “Boson” peak near 50 cm^? 1 has been critically discussed.     

Interaction of the vanadyl (IV) cation with carnosine and related ligands

The interaction of the vanadyl (IV) (VO²⁺) cation with carnosine (the dipeptide β-alanyl-histidine) has been investigated by electron absorption spectroscopy at high ligand-to-metal ratios and at different pH values. The results show that in the range 6.0–8.5, the cation interacts with the imidazole group of four different carnosine molecules and points to the presence of an axially coordinated water molecule. These suppositions were confirmed by the behavior of the VO²⁺/imidazole system, which was investigated under similar experimental conditions, and supported by previous ENDOR (electron-nuclear double resonance) results. The study was complemented with additional measurements using the glycylglycine, glycylglycine/imidazole, and histidine systems as ligands.     

固氮蓝藻Anabaena sp.7120的叶绿素蛋白复合体的分离和光谱特性的研究

用光合膜片增溶和SDS-聚丙烯酰胺凝胶电泳方法,从固氮蓝藻Anabaena sp.7120分离到7条色素带。迁移率较慢的五条叶绿素蛋白复合体带,具有相同的吸收光谱和室温荧光光谱特性。它们的红区最大吸收峰在676nm;蓝区最大吸收峰在438nm。它们的室温荧光发射最高峰在672—673nm;在710,732和740nm都有小峰。这些是CPⅠ叶绿素所特有的。我们认为这5条带都是属于光系统Ⅰ的叶绿素蛋白复合体。另一条迁移率稍快的叶绿素蛋白复合体带为CPⅡ。它的红区最大吸收峰在672nm;蓝区最大吸收峰在436nm。与CPⅠ带相比,两个峰均向短波端偏移。它们的室温荧光发射最高峰在675nm,没有CPⅠ所特有的小峰。这些性质说明此带和CPⅠ带不同,而是和光系统Ⅱ反应中心相关的一个复合体。迁移率最快的带是游离色素带。     

Physicochemical and spectroscopic characteristics of dissolved organic matter extracted from municipal solid waste (MSW) and their influence on the landfill biological stability

For the purpose of evaluating the stability of municipal solid waste (MSW) excavated from a landfill, dissolved organic matter was extracted and characterized by physicochemical and spectroscopic methods. Results showed that dissolved organic carbon concentration, ratio of dissolved organic carbon to dissolved organic nitrogen, and specific ultraviolet absorbance at 254 nm were in the range of 0.383-3.502 g kg⁻¹, 0.388-3.693 and 2.700-4.629 L mg⁻¹ m⁻¹, respectively, indicating the stability of MSW. Results obtained from Fourier transform infrared spectra have demonstrated that the stability of excavated MSW was characterized by disappearance of some easily biodegradable compounds; and the 1635/1406 ratio varied from 0.979 to 1.840 and was higher than that of the matured compost. The excitation-emission matrix spectra have shown that the principal components in excavated MSW comprised humic substances and the MSW was stable by the presence of a peak with wavelength pair of ∼280/420 nm.     

Microspectrophotometric analysis of malarial pigment

The absorption spectra of pigment granules in erythrocytes infected with Plasmodium vivax were examined by microspectrophotometry. Our investigations show that individual pigment granules in infected erythrocytes are different and that gradual transitional stages are found from hemoglobin to a compound with a symmetric absorption spectrum with a maximum at 442 nm. This compound is likely to be the “pure” malaria pigment. The exact nature of this pigment is not clear from the absorption curves; it is certainly not chemically pure hematin or bilirubin.     

突变体大麦Mb1832C的叶绿素蛋白复合体

用低浓度ＳＤＳ对突变体大麦Ｍｂ１８３２Ｃ的类囊体膜进行增溶,再经不连续的ＳＤＳ－聚丙烯酰胺凝胺电泳后,按电泳迁移率的增加顺序,分离出ＣＰＩ,ＣＰａｌ,ＣＰａ２和ＦＣ４条蓝绿色的带。ＣＰＩ在红区和蓝区的吸收峰分别位于６６７ｎｍ和４３８ｎｍ处。低温荧光发射光谱表明ＣＰＩ为含有少量光系统Ⅱ的光系统Ⅰ反应中心复合体。