SENSITIZATION BY LUMAZINE PROTEINS OF THE BIOLUMINESCENCE EMISSION FROM THE REACTION OF BACTERIAL LUCIFERASES

Abstract— Lumazine protein from Photobacterium phosphoreurn blue shifts the in vitro bioluminescence spectra in the reactions using each of the 4 main types of bacterial luciferases: P. phosphoreum, P. leiognathi, Vibrio harveyi and V. fischeri . For the reaction initiated with FMNH₂ and tetradecanal at 2°C, this "sensitizing" property of lumazine protein differs quantitatively between the luciferases. An interaction constant characterizing each type of luciferase may be derived from a reciprocal plot of the spectral shift against the lurnazine protein concentration. The weakest interaction constant is in the V. fischeri reaction, 180 μM. For the V. harveyi reaction the interaction is in the range 6–9 μ M , and for both Photobacterium reactions it is 2–3 μM. A concentration of only 0.6 μ M of lumazine protein is sufficient to cause an observable change in the Photobacterium bioluminescence spectra. For the V. harveyi case the interaction constant is near to the equilibrium K _d for the luciferase-lumazine protein complex, observed directly by Visser and Lee. Both constants are decreased markedly by increase in phosphate concentration so that it is concluded that, with V. harveyi luciferase, sensitization occurs within this protein-protein complex. For P. phosphoreum luciferase, however, the equilibrium complex is too weak to correspond to the sensitizing interaction and it is concluded that the rate-limiting process is a protein-protein bimolecular collision. As judged from their molecular weight around 20000, spectral properties, and ability to blue shift the bioluminescence spectra, lumazine proteins are identified in a second strain of P. phosphoreum and in P. leiognathi .     

水杨醛缩对甲苯胺的吸收光谱和失活动力学研究

利用纳秒级的闪光光解方法研究了水杨醛缩对甲苯胺的瞬态吸收光谱。根据瞬态吸收光谱和动力学数据,该化合物的基本光产物被认为是一个两性离子。实验结果表明,光产物的性质与溶剂的性质和浓度有关。对该化合物的光致变色机理也进行了讨论。     

BIOLUMINESCENCE OF ACETALDEHYDE CATALYZED BY BACTERIAL LUCIFERASE

Abstract— Bioluminescence from the oxidation of acetaldehyde by bacterial luciferase of Photobacterium fischeri has been demonstrated for the first time and its efficiency has been compared with that of nonanal and other short chain aldehydes.     

THE ORIGIN OF BIOLUMINESCENCE*

Abstract— Primitive luciferases evolved in order to utilize oxygen directly as an electron acceptor at the low oxygen concentrations of the primitive atmosphere. This provided a major selective advantage in the ability to metabolize aromatic molecules and n-alkanes. These strongly exergonic reactions produce product molecules in electronically excited states, from which light emission is possible. The low-level luminescence observed from microsomal extracts, from the action of leukocytes on phagocytized bacteria and from rapidly growing tissues is ascribed to these same exergonic hydroxylase reactions, or to the release during these reactions of superoxide radicals which can initiate chemiluminescent reactions. Bioluminescence is a later secondary adaptation of this oxygenase reaction to signaling for sex, food or escape. The similarity of the reaction pathways is shown in the three bioluminescent systems from which the substrates and products have been identified.     

FLASH PHOTOLYSIS OF BOVINE SERUM ALBUMIN: IDENTIFICATION AND DECAY KINETICS OF TRANSIENT INTERMEDIATES

Abstract. Using the method of flash photolysis, the triplet of the single indole side chain of human serum albumin was detected at room temperature. In a nitrogen saturated solution, this species was found to decay exponentially for over a factor of ten with a lifetime τ 0.5 ms. Analogous experiments, reported here, with bovine serum albumin yield a non-exponential decay which may be decomposed into two components. The yield of the longer lived triplet, with an average τ of ∼6 ms, is significantly enhanced by addition of a 20 fold excess of sodium dodecyl sulfate or 1 M Br^-. The yield of the shorter lived triplet, τ 0.4 ms, is unaffected by these treatments as was previously observed for the single indole in HSA. Thus, the short lived triplet may be assigned to the indole in BSA which is homologous to the one in HSA. The longer lived triplet may be assigned to the remaining indole of BSA. On the bases of wavelength dependence studies, two additional transients may be identified; the electron adduct of the disulfide bond, λ; 420 with a τ 30 ms, and the neutral indole radical,λ; 520 nm with τ ls. These results suggest that the triplet, because of its long τ, will be a valuable intrinsic reporter group for the study of the structure and dynamics of proteins in solution at room temperature.     

FLUORESCENT TAUTOMERS AND THE APPARENT PHOTOPHYSICS OF ADENINE AND GUANINE

Abstract— Fluorescence, absorption and fluorescence excitation spectra, and quantum yields of 0.02 mM solutions of adenine, 7-methyladenine (7-MA), guanine and 7-melhylguanine (7-MG) are presented for excitation with240–300 nm light. The solvent is neutral ethylene glycol-water (70:30 v/v) in the temperature range140–165 K. Phosphorescence spectra of adenine and 7-MA at 140 K are also presented. The excitation spectrum of adenine shows vibrational structure, whereas the absorption does not. However, the fluorescence of adenine shows the vibrational structure, as do the absorption, fluorescence and excitation spectra of 7-MA. The results confirm (and reinforce) the notion that luminescence from adenine under these conditions is from the N₇–H tautomer, instead of the more abundant N₉–H form. In a similar fashion, the data from guanine and 7-MG strongly suggest that the luminescence from guanine is also mostly from the N₇–H tautomer.     

聚三氟氯乙烯的热裂解动力学和机理的研究

本文报道在4.1型示差精密热天平上装配了微分单元,组成热重-微商热重(TG-DTG)联用装置用于研究聚三氟氯乙烯在空气中的热裂解动力学过程,并运用几种不同的动力学处理方法所求得的结果来评价各种动力学理论的优缺点和说明聚三氟氯乙烯反应程度在5—95％的整个过程中活化能的变化情况。同时根据裂解程度与能量、裂解速率的关系以及裂解产物结构的鉴定,提出了聚合物无规热裂解机理,解释了迄今文献上所报道的裂解产物的结构。结果还证明了Errede提出的键离解能经验公式不适用于聚三氟氯乙烯的裂解机理。     

KINETICS AND MECHANISM OF THE THERMOLYSIS OF SULFOXIDES

Abstract

The thermolysis of sulfoxides possessing β-hydrogen atoms is a versatile and mild method to prepare olefins. The reaction is generally accepted to proceed via a concerted mechanism. Accordingly, solvent effects are not large, and appear to be associated with the initial states. The reverse process has been documented for R = t-Bu; MeSOH or PhSOH can also be employed.     

TRANSIENT KINETICS OF FLAVOCYTOCHROME c PHOTOREDUCTION BY METHYL VIOLOGEN

Abstract— It has been demonstrated that photoreduced methyl viologen is stable during a flash photolysis experiment if a proper anaerobic environment is maintained. Therefore a new class of potential electron donors can be introduced in the study of transient phenomena associated with intermolecular electron transfer of redox proteins. The transient redox kinetic parameters of the flavocytochrome c from the photosynthetic bacterium Thiocapsa roseopersicina are reported for the first time and compared to similar data published for other fiavoproteins from diverse sources using flavin-type electron donors. The advantages of the photoreduced viologen based transient electron donor system are discussed.     

THE EVOLUTION OF BIOLUMINESCENCE IN BACTERIA

Individuals of aerobic, saprophytic bacterial species, encountering a changing environment in which they were regularly exposed to periods of severe hypoxia, would have gained a major selective advantage in fatty acid metabolism if a mutation in a flavoprotein oxygenase permitted them to oxidize accumulated C₈-C₁₈ aliphatic aldehydes to fatty acids at oxygen concentrations below which the cytochrome oxidase mediated electron transport pathway became inhibited. Such mutants, able to continue to metabolize exogenous lipid fatty acids under hypoxia, might have outproduced their wild type ancestors. Colonies of those mutants which utilized reduced flavin mononucleotide (FMNH₂) as the flavin cofactor would have been luminous, owing to the fortuitous coincidence that the aldehyde oxygenation resulted in an enzyme-flavin excited electronic state which emitted blue light with a high fluorescence yield. If this accidental “proto-bioluminescence” were initially of sufficient brightness to have elicited phototactic responses in nearby motile organisms, increasing thereby detrital food sources or the potential for dispersal and colonization for the bacteria, a new and completely different selective advantage, that of bioluminescent signalling, would have arisen from the original metabolic function. This is the biochemical analog of Darwin's principle of functional change in structural continuity. It is proposed that bacterial luciferase, the FMNH₂-oxygenase in luminous bacteria, was such a mutation. The present ubiquitous distributions of luminous bacterial species in marine waters, on the surfaces of marine animals and as symbionts in the specialized light organs and digestive tracts of many fish species have resulted from subsequent environmental selection and optimization for this original proto-bioluminescent reaction. By extension it is suggested whereas “protobioluminescence” arose in many species independently whenever metabolic oxygenation of a substrate resulted in an adventitiously efficient chemiluminescence, the function of bioluminescence arose only upon favorable interaction between the “proto-bioluminescence” and its ecosystem.     

THE CHEMISTRY AND BIOLOGY OF BACTERIAL LIGHT EMISSION

Abstract—Bioluminescent bacteria may be isolated from sea water, and grown on a medium containing fish (or meat or yeast) extract. Cells harvested at the peak of luminescence can be lysed osmotically, releasing into the medium the soluble enzyme bacterial luciferase, which catalyzes the bioluminescent oxidation of reduced riboflavin 5′-phosphate and long chain aldehyde by molecular oxygen. Luciferase is the simplest possible heterpolymeric protein, with an α (catalytic, 42,000 daltons)-β (regulatory, 37,000 daltons) dimeric structure. Luciferase is not constitutive; it is induced by a substance produced by the bacteria themselves and excreted into the medium. Control also involves repression (glucose) and cyclic nucleotides. Recent work has resulted in the characterization of an intermediate in the light emitting reaction postulated to be luciferase-bound 4a-peroxy-dihydro FMN. The final steps in the in vitro light-emitting reaction involve reaction of this peroxy intermediate with aldehyde in a mixed function oxidase-type reaction, yielding an excited luciferase-flavin and long chain acid. The excited state is postulated to be the luciferase-bound 4a-hydroxy-dihydro-FMN. Although the identity of the in vivo aldehyde, its localization and its metabolism is unknown, studies with mutants which fail to synthesize aldehyde suggest that the 14 carbon fatty acid is a precursor. Moreover, although bacterial luciferase is highly soluble (200 mg ml^-1 in aqueous solution) there is recent evidence from our laboratory and others that its function may involve the cytoplasmic membrane. The function of light emission is of particular interest since a considerable amount of energy is involved; assuming a quantum yield of 10%, the cell foregoes the production of about 60 ATP molecules per photon. A fully induced cell emits about 10⁴ quanta/s and about 20% (!) of the oxygen consumption of the cell has been estimated to go via the light emitting pathway. One function is in light organs of higher organisms, where they occur as symbionts. The inducible (and repressible) nature of the luminescent system may be appreciated in terms of ecological options; the bacteria may be biologically very versatile. Induction by an inducer produced by the bacteria themselves would occur only under conditions where it accumulates, as in a luminous organ of a host. In the open ocean such an accumulation does not occur; the luminous system would thus not be synthesized and energy loss via luminescence is averted, allowing the bacteria to compete in an alternate “life style”.     

聚苯类共轭聚合物的合成及荧光特性研究

聚苯类共轭聚合物的合成及荧光特性研究李建科阳明书漆宗能王佛松（中国科学院化学研究所工程塑料国家重点实验室北京１０００８０）关键词聚对苯，共轭聚合物，吸收光谱，荧光光谱，发光共轭聚合物在非线性光学、光电化学池、二次电池等方面有着广泛的应用前景，近...     

ON THE MECHANISM OF PHAUSIS SPLENDIDULA BIOLUMINESCENCE

Evidence is presented for cross reactivity between the luciferases and luciferins of Phausis splendidula and Photinus pyralis.     

金属复合催化剂对煤气化的暂态动力学研究

采用阶跃扰动技术进行了金属复合催化剂对煤气化的暂态动力学研究。根据实验结果推导得出了该反应过程是催化剂表面富氧活性部位先与煤焦反应生成一个CO分子，然后此CO分子从催化剂表面脱附，接着催化剂吸附气态的CO2生成一个CO并且夺得一个氧原子实现自身还原的过程，在此基础上建立了煤的催化气化的物料平衡方程组，对各步骤的反应速率常数进行了求解，在本文采用的实验条件下，各反应步骤的反应速率常数分别为0.0703 mol·g-1·min-1·kPa-1;0.0959 mol·g-1·min-1·kPa-1;0.00539 mol·g-1·min-1·kPa-1; 0.0321mol·g-1·min-1·kPa-1。由此得出了该反应历程的控制步骤为CO2的吸附步骤等历程信息。     

BIOLUMINESCENCE OF THE BRITTLE STAR OPHIOPSILA CALIFORNICA

The light-emitting principle of the brittle star Ophiopsila californica has been isolated and purified. It was found to be a green-fluorescent photoprotein (molecular weight 45000) which emits green light (λ_max 500 nm) when H₂O₂ is added, independently of the presence or absence of O₂. The green fluorescence (emission maximum 500 nm, excitation maximum 440 nm) spectrally coincided with the H₂O₂-triggered luminescence, indicating that the green fluorescent chromophore is the light-emitter of the photoprotein luminescence.