口腔常见致龋菌荧光光谱特征的初步研究

目的采用三维荧光光谱分析技术对口腔常见致龋菌荧光光谱特征进行初步分析。方法选择口腔常见致龋菌变形链球菌及远缘链球菌,对其进行复苏和培养,运用三维荧光光谱分析技术对其菌液进行荧光学光谱检测。结果变形链球菌及远缘链球菌的三维荧光光谱图相似,均出现2个荧光峰,最佳激发波长分别位于230nm和280nm,最佳发射波长相同,均为340nm。结论成功获得口腔常见致龋菌(变形链球菌及远缘链球菌)的固有荧光三维光谱图,为致龋菌荧光评价技术的应用提供参考。     

光系统Ⅱ捕光复合体飞秒时间分辨荧光特性的研究

采用时间分辨荧光光谱技术研究了菠菜（Spinacia oleracea L.）叶绿体叶捕光色素复合体（LHC Ⅱ）荧光的时间特性和光谱特性。用脉宽为120fs、波长为400nm的倍频钛宝石激光激发LHCⅡ样品;原始荧光信号由Boxcar采集,通过建立多指数模型,用非线性最小二乘法拟合,得到了激发能在LHCⅡ中传递的时间常数分别为：320fs、4.0ps和20.0ps。相对应的各组分荧光占总荧光的非分比分别为：3.4%、50.0%和46.6%。经全局分析,解得荧光强度随波长变化曲线;用高斯3峰解叠得到荧光光谱的峰值波长分别为：652nm、672nm和691nm。通过分析得出了时间常数与LHCⅡ中各色素成分之间的对应关系,并给出了可能的能量传递模型。     

赤霉素及竹红菌甲素荧光量子产率的常量化区域

通过对赤毒素、竹红菌甲素及苯酚量子产率的测定与比较发现,这三种荧光化合物都具有一个相对于激发波长的量子产率的稳定区域。尽管它们具有多个激发峰,但不同激发峰所激发的荧光量子产率差别较小。竹红菌甲素在室温放置一个月,690nm荧光光谱有明显的改变。以上结果提示在测定未知荧光化合物的量子产率时,被测溶液的散射较强,同时荧光物的激发与发射波长彼此相接近。量子产率较弱时,可以在最大激发峰的蓝移方向上选择激发波长来避免散射光的干扰,提高量子产率测定的准确度。竹红菌甲素在690nm的荧光肩峰,可能是分子空间结构上容易发     

近红外与荧光光谱法检测血糖试验研究

采用荧光光谱法检测血糖。结果表明,检测血清的最佳激发波长为340 nm,血清中葡萄糖的发射峰位置为470 nm。随着血清中葡萄糖浓度的增加,荧光光谱图中荧光峰处荧光强度,面积积分强度整体呈上升趋势,荧光峰的半峰全宽整体呈现下降趋势。利用近红外光谱法检测血糖,血清可分辨的光谱区域位于5 600~6 060 cm-1范围内,不同血糖浓度的吸收峰均位于5 768 cm-1处。随着血糖浓度的增大,其吸收峰处的吸光度逐渐增大,面积积分强度也呈上升趋势。分析二者的优缺点,荧光分析法受外界因素的干扰更小,精确度更高,光谱参数与血糖浓度之间的规律更明显,在有创检测方面具有更明显的优势,而近红外光谱法检测血糖则在无创血糖检测方面具有更大的潜力。     

雨生红球藻(Haematococcus pluvialis)的光谱特性研究

实验测定了雨生红球藻不同生长阶段的色素组成,吸收光谱,荧光光谱,并对其进行了分析。结果表明,用490nm波长激发时,雨生红球藻在绿色细胞阶段存在710nm和730nm附近的长波长荧光发射峰,而在红色细胞阶段仅存在730nm的长波长荧光发射峰,预示着雨生红球藻不同生长阶段在PSⅠ结构,组成,及其色素蛋白的排布等方面有很大差异。     

荧光光谱分析法在地沟油鉴别中的应用研究

由于地沟油的成分含量复杂性和不定量性,导致了现有的单一检测方法不能同时满足快速和准确的辨认。荧光光谱具有高灵敏度和分辨率的特性,由此提出了一种利用荧光光谱快速检测食用油中是否掺有地沟油的新方法。将花生油分成7组,每组油所含的地沟油的比例不同,用220 nm到800 nm的激发和发射光检测各组样品油,收集其荧光数据后做归一化处理进行分析。在荧光实验中,特别是在365 nm和720 nm激发波长波段和434 nm发射波长波段,样品油的荧光强度与所含地沟油的体积分数大小明显成反比,当地沟油的体积分数大于5%时,荧光强度的衰减更为明显。结果证明了荧光光谱法检测地沟油的可行性,而且步骤更为简单。利用荧光光谱的非接触和高灵敏度的优势,能够更为简便地检测到加入了5%以上地沟油的花生油。     

人体鼻咽组织的时间分辨自体荧光光谱研究

实验研究了在397 nm半导体脉冲激光激发下,人体离体鼻咽正常和癌变组织在600 nm荧光发射波长处的时间分辨自体荧光光谱特性。利用双指数衰减方程对时间分辨自体荧光光谱进行拟合后,获得相应的荧光强度随时间的指数衰减方程以及荧光平均寿命。人体鼻咽癌变和正常组织在600 nm处的自体荧光平均寿命分别为(2.94±0.51)ns和(4.29±0.71)ns,两者之间存在显著的差异。应用时间分辨光谱技术的诊断灵敏度和特异性分别为75%和100%。初步表明了时间分辨自体荧光光谱在早期鼻咽癌诊断的应用价值,该方法可望与传统的稳态荧光光谱结合起来,进一步提高早期鼻咽癌荧光诊断的准确率。     

癌症病人血液的荧光光谱研究

研究了癌症病人全血、血浆和血红蛋白的激发波长—发射波长—荧光光强三维光谱,观察到特征谱带625nm的荧光本原物质存在于血红蛋白部分,比较了十五种癌症(28例),十例非癌症病人和健康人血液在625nm带的荧光强度.     

癌症病人血液的荧光光谱研究

研究了癌症病人全血、血浆和血红蛋白的激发波长—发射波长—荧光光强三维光谱,观察到特征谱带625nm的荧光本原物质存在于血红蛋白部分,比较了十五种癌症(28例),十例非癌症病人和健康人血液在625nm带的荧光强度.     

橙色荧光蛋白——绿色荧光蛋白GFPxm的改造

最近报道了从大型多管水母中分离出新的gfp基因。经大肠杆菌表达并纯化出的绿色荧光蛋白 (GFPxm)具有 4 76nm的激发峰和 4 96nm的发射峰 ,但是只能在低温下成熟的缺点限制了它的应用。这里进一步报道GFPxm的 12种突变型。在大肠杆菌中的表达结果表明 ,有 7种突变型在 37℃条件下产生高的荧光强度。在 2 5、32和 37℃条件下表达 6h ,GFPxm16、GFPxm18和GFPxm19的相对荧光强度均高于增强型绿色荧光蛋白 (EGFP) ,而GFPxm16和GFPxm16 3在 4 2℃高温表达时仍能保持高的荧光强度。这 7种突变型中的 4种在哺乳动物细胞中已获得良好表达。此外 ,有 6种突变型的荧光光谱红移 ,目前所达到的最长激发峰为 5 14nm、最长发射峰为 5 2 5nm。另外有 3种突变型具有包括紫外在内的两个激发峰 ,1种突变型只有单一的紫外激发峰。首次报道具有橙色荧光的突变型OFPxm ,它的激发峰为 5 0 9nm、发射峰为 5 2 3nm。 5 2 3nm属于黄绿色 ,但肉眼看到的蛋白为橙色。OFPxm在高温下可得到高水平表达且很好地成熟 ,但是因为低的量子产率而荧光强度相对较低。     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Interconnection of parameters of regulation system of lipid peroxidation and of morphophysiological parameters of mouse liver

A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.     

Physiological characteristics of various species of strains of carboxydobacteria

Seven strains of aerobic carbon monoxide-oxidizing bacteria (carboxydebacteria) when growing on CO as sole source of carbon and energy had doubling times which ranged from 12–42 h. The activity profiles obtained after discontinuous sucrose density gradient centrifugation indicated that the CO-oxidizing enzymes are soluble and the hydrogenases are membrane-bound in all strains examined. The CO-oxidizing enzymes of Pseudomonas carboxydohydrogena, Pseudomonas carboxydoflava, Comamonas compransoris, and the so far unidentified strains OM2, OM3, and OM4 had a molecular weight of 230,000; that of Achromobacter carboxydus amounted to 170,000. The molecular weights of the CO-oxidizing and H₂-oxidizing enzymes turned out to be identical. The cell sonicates were shown to catalyze the oxidation of both CO and H₂ with methylene blue, thionine, phenazine methosulfate, toluylene blue, dichlorophenolindophenol, cytochrome c or ferricyanide as electron acceptors. Methyl viologen, benzyl viologen, FAD⁺, FMN⁺, and NAD(P)⁺ were not reduced. The spectrum of electron acceptors was identical for all strains tested. Neither free formate, hydrogen nor oxygen gas were involved in the CO-oxidation reaction. Methylene blue was reduced by CO at a 1:1 molar ratio. The results indicate that CO-oxidation by carboxydobacteria is catalyzed by identical or similar enzymes and that the reaction obeys the equation CO+H₂OCO₂+2H⁺+2e^- as previously shown for Pseudomonas carboxydovorans.Dedicated to Otto Kandler remembering almost three decades of enjoyable cooperation     

Modulation of allostery of pyruvate kinase by shifting of an ensemble of microstates

Since the introduction of the concepts of allostery about four decades ago, much advancement has been made in elucidating the structure-function correlation in allostery. However, there are still a number of issues that remain unresolved. In this review we used mammalian pyruvate kinase (PK) as a model system to understand the role of protein dynamics in modulating cooperativity. PK has a triosephosphate isomerase (TIM)(α/β)₈ barrel structural motif. PK is an ideal system to address basic questions regarding regulatory mechanisms about this common (α/β)₈ structural motif. The simplest model accounting for all of the solution thermodynamic and kinetic data on ligand-enzyme interactions involves two conformational states, inactive E^T and active E^R. These conformational states are represented by domain movements. Further studies provide the first evidence for a differential effect of ligand binding on the dynamics of the structural elements, not major secondary structural changes. These data are consistent with our model that allosteric regulation of PK is the consequence of perturbation of the distribution of an ensemble of states in which the inactive E^T and active E^R represent the two extreme end states. Sequence differences and ligands can modulate the distribution of states leading to alterations of functions. The future work includes: defining the network of functionally connected residues; elucidating the chemical principles governing the sequence differences which affect functions; and probing the nature of mutations on the stability of the secondary structural elements, which in turn modulate allostery.     

Cause of Senescence of Nine Sorts of Flowers

The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.     

（鱼句）亚科花（鱼骨）型鱼类骨骼系统的比较

对我国花型Hemibarbuspattern鱼类作了骨骼系统比较,结果表明,此类型鱼类脑颅较长,副蝶骨平直或稍弯曲,眶蝶骨腹纵嵴发达(铜鱼Coreius septentrionalis例外),下颞窝和咽突中等大,基枕骨后突发达;脑颅中的上筛骨的后突、侧筛骨的外筛突,蝶耳骨的外突、上耳骨的后突、围眶骨和后颞窝等均有明显的差异;咽颅中的舌颌骨、尾舌骨、鳃盖骨和下咽齿的列数等又有显著的区别;附肢骨骼中的腰带骨、脊椎骨中的复合神经骨和第4椎骨腹侧的悬器等也有不同之处。据此,这些差异和区别可作为属间或种间的分类依据。     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.