PHYTOCHROME SYNTHESIS DURING IMBIBITION IN EMBRYONIC AXES OF Pisum sativum L.*

Abstract— The exact quantity of phytochrome in crude homogenates (2kS) prepared from embryonic axes of Pisum sativum during imbibition at 25°C on 0,2% agar was estimated optically. The problem of the scattering factor was solved by using highly purified phytochrome as an internal standard. The content of phytochrome protein moiety in diluted samples of the crude homogenates of the axes was also determined by an enzyme-linked immunosorbent assay (ELISA). Phytochrome was not detectable either spectropho-tometrically or immunochemically in 2kS of dormant dry axes. Embryonic axes quickly absorbed water during the first1–2 h after the start of imbibition, after which the fresh weight stayed at a constant level for a further 10 h. The content of spectrophotometrically detectable phytochrome increased during imbibition in the dark, reaching about 0.2 μ.g/axis after 12 h. The amount of phytochrome in 2kS of axes in the light was so small that only about 0.05 μg/axis was detected after 12 h. The content of immunochemically detectable phytochrome greatly increased up to ca. 0.5 μg/axis after 12 h of dark incubation. In 2kS of the light-grown axes the content of the phytochrome protein was ca. one fourth lower than in dark-grown axes. We conclude that the appearance and increase of phytochrome in fragments of imbibed embryonic axes were caused by de novo synthesis and that the contents of both photometrically detectable phytochrome and its protein moiety in the light-grown samples were lower than those in the dark throughout the early germination process.     

A POSSIBLE CONTROL BY PHYTOCHROME and OTHER PHOTORECEPTORS OF PROTEIN ACCUMULATION IN THE GREEN ALGA Ulva rigida

Abstract— The effects of red, blue and green light pulses on total protein accumulation in the green alga Ulva rigida following transfer from a low to high nitrate medium in darkness were examined. Red light pulses prior to transfer to darkness increased protein accumulation by about 55%. Blue and green light pulses also stimulated protein accumulation, but to a lesser extent (40-30% respectively). Stimulation of protein accumulation by red, blue or green light was largely (red light) or partially (blue or green light) reversible by far-red. The role of phytochrome and a red/green photoreversible system in the control of protein synthesis is discussed.     

THE EFFECT OF LIGHT QUALITY IN Prunus cerasus. I. PHOTORECEPTORS INVOLVED IN INTERNODE ELONGATION AND LEAF EXPANSION IN JUVENILE PLANTS

Evidence is presented to suggest that stem elongation in this woody species is controlled not only by phytochrome as previously suggested for other woody species, but also by a specific blue absorbing pigment (BAP). In contrast, the BAP seems to have no role to play in the development of total leaf area in these juvenile specimens.     

2-氨基-1,3,4-噻二唑的抗水稻白叶枯病机制的探讨

药师寺国人等于1971年发现2-氨基-1,3,4-噻二唑(ATDA)具有优越的抗水稻白叶枯病菌的性能,并发现这种性能可被烟酰胺抵消.一般认为,ATDA的作用与细菌细胞中烟酰胺的代谢有关.为了探明ATDA的活性与结构的关系,并从中找出有效的同类化合物,进一步了解这个药剂的抗病机制,我们合成了几类新的噻二唑化合物,连同以前报导的     

INTERACTION OF RHODOPSIN, G-PROTEIN AND KINASE IN OCTOPUS PHOTORECEPTORS

Light induced phosphorylation of octopus rhodopsin was greatly enhanced by guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S), suggesting that the kinases are involved in regulating interaction between rhodopsin and G-protein. We determined phosphorylated peptides of octopus rhodopsin in the presence or absence of GTP gamma S. Possible phosphorylation sites for octopus rhodopsin enhanced by GTP gamma S were Thr329, Thr330 and/or Thr336, which suggest that the G-protein associates with cytoplasmic loops including C-terminal peptide in the seventh helix of octopus rhodopsin.     

IDENTITY OF THE PHOTORECEPTORS FOR THE PERCEPTION OF IRRADIANCE IN PHOTOSYNTHETIC LIGHT ACCLIMATION IN TOMATO*

The photoreceptors involved in the photosynthetic acclimation of tomato (Lycopersicon esculentum Mill.) to increased irradiance were investigated. Plants were transferred from 100 p.mol m^?2 s^?1 cool white fluorescent light to higher irradiances of white light or white light supplemented with blue, red, green or yellow light. In these experiements light of all wavelengths tested was capable of causing acclimation as measured by the rate of light-saturated photosynthesis. It was concluded that the photosynthetic system rather than the blue-absorbing photoreceptor or phytochrome system acts as the photoreceptor for increased irradiance. No acclimation was observed in response to increased CO₂ levels, but increasing light integral at a constant irradiance was effective in bringing about acclimation. We conclude that acclimation is a response to increased photosynthetic light capture rather than increased photosynthetic carbon fixation, and involves a photon counting mechanism.     

高效液相色谱法检测底泥中孔雀石绿及其代谢物

以乙腈、二氯甲烷、对甲苯磺酸和Mcilvain缓冲液等提取底泥中孔雀石绿和隐色孔雀石绿,以乙腈-甲醇-乙酸钠缓冲液为流动相,用DAD检测器在618nm处进行检测,建立了底泥中孔雀石绿及其代谢物的HPLC检测方法。孔雀石绿的回收率为75.2%~79.1%,隐色孔雀石绿的回收率为81.1%~84.2%,检测限均为5μg/kg。     

TRANSPORT OF LIGHT IN TISSUE IN PHOTODYNAMIC THERAPY

Abstract The dose rate in photodynamic therapy is proportional to the energy fluence rate and the concentration of the photosensitizer. Calculations of the energy fluence rate have been performed in slab, cylindrical and spherical geometries with the discrete ordinates transport method and diffusion theory. The attentuation of the energy fluence rate is least in slab geometry and greatest in spherical geometry. Violet (405 nm) light is attenuated much more rapidly than red (630 nm) light. Small tissue dimensions or narrow beam irradiation further decrease the energy fluence rate with radius and depth. Anisotropic scattering increases the energy fluence rate at large depths, but decreases it near the source. Measurements of the absolute energy fluence rate vs depth in a mouse tumor model exhibit an order of magnitude attenuation through the skin and a 3 mm thick tumor. Calculations of the energy fluence rate of the DHE fluorescence have been carried out to guide measurement of the concentration. Violet light excitation is much more efficient than red light excitation.     

间接光度法测定植物叶片中叶绿素含量

将植物叶试样置于研钵中用无水乙醇研磨,使植物叶中叶绿素溶入乙醇中。分取部分此乙醇溶液用石油醚萃取,使叶绿素溶入石油醚中。石油醚相用1 mol.L-1盐酸反萃取,使镁离子从叶绿素分子中被氢离子置换而进入水溶液中。然后用光度法以偶氮氯膦Ⅰ为显色剂测定镁量并用以计算叶绿素的含量。     

QUANTUM EFFICIENCY AND PHOTOSENSITIVITY OF THE RHODOPSIN ⇌ METARHODOPSIN CONVERSION IN CRAYFISH PHOTORECEPTORS

Photosensitivity (K_λ) of a visual pigment is the product of the molecular absorption coefficient (α_λ) and the quantum efficiency for photoconversion (γ). Among the invertebrates, many visual pigments are stable not only in the rhodopsin (R) conformation but also as the photoproduct, metarhodopsin (M), We here employ a method for determining the photosensitivities of the two stable pigments of a rhodopsin-metarhodopsin pair, using kinetic analysis of fluorescence from metarhodopsin combined with measurements of spectral absorption made before and after saturation at the isosbestic wavelength of the pigment pair. A curve fitting technique, in which a theoretical function is scaled for best fit to the measured absorption spectrum of the photosteady-state mixture, yields values for the photosensitivity of rhodopsin at λ._max, the ratio of quantum efficiencies for rhodopsin—metarhodopsin interconversion, and the fractional composition of the steady-state mixture. With knowledge of the molecular extinction coefficient, the absolute values of quantum efficiency can be calculated. For crayfish ( Orconectes, Procambarus ) rhodopsin, measured in isolated rhabdoms, K_max= 1.05 x 10^-16 cm² at 535 nm with >7λR→M0.69. These values are similar to the photosensitivity and quantum efficiency of bleaching of vertebrate rhodopsins in digitonin solution (Dartnall, 1972). For the metarhodopsin, K_max= 1.02 x 10^-16 cm² at 510 nm, and λ_M-R= 0.49.     

ARE THERE SEVERAL PHOTORECEPTORS INVOLVED IN PHOTOTROPISM OF Phycomyces blakesleeunus? KINETIC STUDIES OF DICHROMATIC IRRADIATION*

Abstract— Photogeotropic equilibrium angles were measured for Phycomyces blakesleeanus wild type firstly by means of dichromatic fluence rate response curves using simultaneous irradiation with near threshold 450 nm reference light (constant at 1.2 × 10^?8 W m^?2) and variable fluence rates of test light (498–630 nm) from the same side. These curves showed minima for test light fluence rates that were close to the photogeotropic threshold for these wavelengths. Secondly, the time course of this inhibitory effect was studied with both the inductive reference 450 nm light (2 × 10^?-⁷ W m^?2) and the test light (606 or 450 nm) given as light pulses of 2 s duration (2 s light/48 s dark periods for 6 h). The dark period between the onset of the inductive reference light and test light pulses was varied between 0 and 48 s. No inhibitory effects were observed for simultaneous pulses; however, inhibitory effects were demonstrated for delay times of 2 s and 20 s for 606 nm as well as 450 nm test light. If the test light pulses were given immediately before the inductive reference light, only 606 nm test light was effective in producing a significant inhibitory effect. The results are discussed with regard to a multichromophoric photoreceptor system and to the wavelength dependence of the effects observed. The data and conclusions favor a photoreceptor system with at least two separate chromophoric absorptions of the blue light receptor type, one acting positively, the other acting inhibitorily, and at least one other photoreceptor of presumably minor influence.     

反相高效液相色谱法测定毛竹叶中总黄酮

用反相高效液相色谱法,RP－C8柱为固定相,甲醇－水－冰乙酸（40＋60＋2）为流动相,以芦丁为参照物外标法定量,辅以二极管阵列检测技术,测定了毛竹叶中总黄酮的含量,并与光度法作了比较。     

THE α-OXIDASE SYSTEM OF YOUNG PEA LEAVES (Pisum sativum) AS GENERATOR OF ELECTRONICALLY EXCITED STATES. EXCITATION IN THE DARK UNDER NATURAL CONDITIONS

Abstract. The aerobic oxidation of saturated long chain fatty acids to the lower aldehyde and CO₂ catalyzed by the α-oxidase system of young leaves from germinating Pisum sativum results in concomitant excitation of the chloroplasts or/and fractions present in the α-oxidase preparation. The excitation is attested to by both chlorophyll emission and Hill activity. This is the first case of photobiochemistry without light within a natural system.     

原子吸收分光光度计检定最佳测试条件的选择

介绍原子吸收分光光度计检定最佳测试条件的选择技巧。     

MECHANISM OF OXYGEN DETOXIFICATION IN NEONATAL RAT LUNG TISSUE

Abstract— Pulmonary macrophages obtained from neonatal rats contain approximately four times the activity of cyanide resistant superoxide dismutase and catalase compared with the cells from adult animals. The activity is highest immediately after birth and diminishes with age until the minimum level is reached at approximately 3 weeks of age. Superimposed upon this change in basal activity is the capability of neonatal cells to synthesize additional cyanide resistant superoxide dismutase and catalase when either the animals or isolated pulmonary macrophages are exposed to 95–100% oxygen. The inductive effect begins at 2–3 days after birth, peaks at 10 days, and disappears at approximately 15 days after birth. In contrast to adult rats, neonatal rats are extremely resistant to the toxic effects of oxygen. If, however, the oxygen mediated increase in both enzymes is prevented or the maximum effective pulmonary macrophage number is diminished in test animals, these animals become vulnerable to toxic effects of oxygen exposure, observed by gross and histologic examination of lung tissue, in a manner similar to adult animals. These data indicate that both cyanide-resistant superoxide dismutase and catalase may be part of the endogenous defense mechanisms which provide neonatal rats with an exceptional resistance to oxygen toxicity.     

丁二烯与丙烯腈共低聚反应中共聚物组成的控制

在二元共聚反应中,为了制备具有均匀组成的共聚物,对于分批聚合,在反应过程中须补加消耗较快的单体以保持单体的浓度比为常数。本工作提出了为控制共聚物组成在反应过程中补加单体的计算方法,它不仅适用于丁二烯与丙烯腈的共低聚反应,也适合于其它二元共聚反应。用这种方法制备了具有均匀组成的丁二烯与丙烯腈共低聚物。