ISOLATION OF PHOTOCHEMICAL REACTION CENTERS FROM A CAROTENOIDLESS MUTANT OF RHODOSPIRILLUM RUBRUM*

Lauryl dimethyl amine oxide was used to isolate reaction centers from a carotenoid-less mutant, strain G-9, of Rhodospirillum rubrum. These reaction centers have absorption spectra and light or chemically induced difference spectra very similar to those obtained from Rhodopseudomonas spheroides, strain R-26. But, unlike those from Rps. spheroides, they are more labile to higher detergent concentrations and to ammonium sulfate. The cytochrome content was estimated to be less than one per 10 P870.     

ISOLATION and SPECTROSCOPIC CHARACTERIZATION OF THE B875 ANTENNA COMPLEX OF A MUTANT OF Rhodopseudomonas sphaeroides

Abstract— We describe a procedure of purification of the B875 antenna complex isolated from the 3P17 mutant strain of Rhodopseudomonas sphaeroides, enriched in B875. The integrity of this isolated complex, as well as a very low content of residual B800-850 antenna, was suggested from low temperature absorption and resonance Raman spectra. Time resolved experiments were also carried out. The important result is the identity of the fluorescence lifetime of the B875 isolated complex (0.64 ± 0.03 ns) with that of the B875 antenna in vivo (0.63 ns), in the membrane of the C71 reaction center-less mutant of Rhodopseudomonas sphaeroides, measured in our previous study.
Our data suggest that the interactions between the bacteriochlorophylls of the complex, as well as the constraints imposed by their protein environment are not much changed from the in vivo state.     

A SCALAR IRRADIANCE FIBER-OPTIC MICROPROBE FOR THE MEASUREMENT OF ULTRAVIOLET RADIATION AT HIGH SPATIAL RESOLUTION

Abstract— The construction of a new type of microprobe for the measurement of scalar irradiance (integral dose rate) in the UV down to wavelengths of 250 nm is described. The microprobes were made from tapered standard optical fibers and a tip-diffuser of magnesia/silica vitroceramic. The sensing tips were ca 100 μm in diameter and had maximal deviations in the angular response of ± 15%. I present measurements of scalar irradiance at high spatial resolution within dry beach sand and suspensions of microorganisms. These two media are environments in which microorganisms are exposed to UV, either under natural (sand) or laboratory conditions (suspensions). In both cases, the space distribution of UV scalar irradiance, and thus the distribution of integral dose rates, departed significantly from that predicted by absorptive effects alone. The results underscore the importance of small-scale, in situ measurements of scalar irradiance for UV dosimetry in such scattering media.     

RATIOING FLUOROMETER PROBE FOR LOCALIZING CARCINOMA IN SITU IN BRONCHI OF THE LUNG

Abstract A bronchoscopic ratioing fiuorometer probe, that ratios the red light emitted from bronchial tumor to the green light of autofluorescence upon stimulation by violet light (413 nm) has proven capable of detecting and localizing small bronchial tumors bronchoscopically, 4, 48, and 72 h after intravenous Photofrin II injection. Still to be determined is whether'field averaging'in the case of very small bronchial carcinoma in situ will diminish accuracy. The accuracy, efficiency, and cost of localization by imaging fluorescence bronchoscopy will be compared to that by non-imaging ratioing fiuorometer probe.     

棕色固氮菌变种UW45缺辅基钼铁蛋白的分离及性质研究(Ⅰ)

应用DEAE-11#纤维素柱层析,结合无氧制备电泳从棕色固氮菌变种uw45无细胞抽提液中分离得到了一种电泳纯蛋白质,回收率为18.4%。该蛋白与FeMoco重组可以催化乙炔还原成乙烯,比活可达5.85nM乙烯/分·毫克蛋白,比其无细胞抽提液活性提高22.7倍。该蛋白与FeMoco重组之后,电泳迁移率明显变慢,更接近棕色固氮菌钼铁蛋白,含铁量增加一倍,井含钼,分子量22万,可见光谱与棕色固氮菌钼铁蛋白的相同。因此,我们认为uw45缺辅基铜铁蛋白与FeMoco重组之后形成了类似棕色固氮菌钼铁蛋白的活性蛋白。     

ANALYSIS OF MULTIPLE PHOTORECEPTOR PIGMENTS FOR PHOTOTROPISM IN A MUTANT OF Arabidopsis thaliana

Abstract
The shape of the fluence-response relationship for the phototropic response of the JK224 strain of Arabidopsis thaliana depends on the fluence rate and wavelength of the actinic light. At low fluence rate (0.1 μmol m^-2s^-1), the response to 450-nm light is characterized by a single maximum at about 9 μmol m^-2. At higher fluence rate (0.4 μmol m^-2s^-1), the response shows two maxima, at 4.5 and 9 μmol m^-2. The response to 510-nm light shows a single maximum at 4.5 μmol m^-2. Unilateral preirradiation with high fluence rate (25 μmol m^-2s^-1) 510-nm light eliminates the maximum at 4.5 μmol m^-2 in the fluence response curve to a subsequent unilateral 450-nm irradiation, while the second maximum at 9 μmol m^-2 is unaffected. Based on these results, it is concluded that a single photoreceptor pigment has been altered in the JK224 strain of Arabidopsis thaliana.     

A SIMPLE AND IMPROVED METHOD OF ISOLATION AND PURIFICATION FOR NATIVE OAT PHYTOCHROME

Abstract— A simple procedure for the isolation and purification of 124 kDa phytochrome (phyA) from etiolated Avena seedlings has been developed employing ammonium sulfate back-extraction. After solubilization of the ammonium sulfate precipitate (250 g/L) an additional ammonium sulfate fractionation with 17 g per 100 mL rather than column chromatography was performed. After several steps of the "washing-out" procedure with 100 mM phosphate buffer, phytochrome was solubilized in 10 m M phosphate buffer. The resulting phytochrome had a specific absorbance ratio (SAR = A₆₆₆/A₂₈o) ranging from 0.60 to 0.85. These values are equivalent to those of phytochrome preparations after hydroxyla-patite chromatography-ammonium sulfate back-extraction. The total isolation-purification time was 8 h and yield of the chromoprotein was 50% higher than the yield using conventional techniques. The phytochrome preparation, after application to a Toyopearl HW-65S gel filtration column, produced very pure 124 kDa phyA with a specific absorbance ratio greater than 1.00. The spectral characteristics are identical to those described for the best of the highly purified native chromoprotein preparations.     

EVIDENCE FOR INVOLVEMENT OF PHYTOCHROME REGULATION IN MALE STERILITY OF A MUTANT OF Oryza sativa L.

Abstract— A rice mutant ( Oryza sativa L. Nongken 58S) "Hubei photoperiod-sensitive genie male-sterile rice" ( ms mutant) has been found to be male sterile under long day cycles (LD) and fertile in short day cycles (SD). After formation of the secondary rachis-branch primodia the mutant plants under SD were interrupted in the middle of the long night phase (night break) for 10 days with 5 min pulses of red light (R) or far-red light (FR). Rates of normal pollen and seed setting of the mutant treated by R or R → FR → R declined significantly, while the rates after FR or R → FR treatments were similar to those under SD alone. The result of these induction reversion experiments is consistent with the operational criteria for the involvement of photochrome. Wild-type rice ( O. sativa L. Nongken 58) under the same treatment showed no change in fertility. Experiments on the effect of different dark intervals (20 s to 15 min) between R and FR on male sterility of the ms mutant showed that the longer the dark interval, the greater the escape of R induction from FR reversibility. Treatment with SD or LD after formation of pollen mother cells had no influence on fertility of the ms mutant plants treated previously with R or FR night breaks.     

BIOCHEMICAL ISOLATION AND SPECTROSCOPIC CHARACTERIZATION OF POSSIBLE PHOTORECEPTOR PIGMENTS FOR PHOTOTAXIS IN A FRESHWATER Peridinium

Photoreceptor pigments have been isolated biochemically from the freshwater dinoflagellate Peridinium gatunense, and characterized spectroscopically. At least four different chromoproteins can be detected in the crude extract and the membrane fraction isolated from the cells absorbing at 580, 638, 667 and 710 nm, which correspond with the maxima in the action spectrum for phototaxis in this organism. Light energy absorbed by shorter wavelength pigments is emitted as fluorescence at wavelengths which are absorbed by pigments with maxima at longer wavelengths. Protein separation on a MonoQ anion exchanger column using fast liquid chromatography resulted in a non-bound fraction and four bound fractions eluted by an NaCI gradient, which differed in their pigment composition.     

PHYSIOLOGICAL CHARACTERIZATION OF A HIGH-PIGMENT MUTANT OF TOMATO

Abstract— A high-pigment (hp) mutant, which shows exaggerated phytochrome responses and three other genotypes of Lycopersicon esculenrum Mill. cv. Ailsa Craig: the aurea (au) mutant deficient in the bulk light-labile phytochrome (PI) pool, the au, hp double mutant, and their isogenic wild type, were used in this study. Measurements of phytochrome destruction in red light (R) revealed that the exaggerated responses of the hp mutant are not caused by a higher absolute phytochrome level or a reduced rate of phytochrome destruction. Fluence-response relationships for anthocyanin synthesis after a blue-light pretreatment were studied to test if the hp mutant conveys hypersensitivity to the far-red light (FR)-absorbing form of phytochrome (Pfr), i.e. the threshold of Pfr required to initiate the response is lower. The response range for the hp mutant and wild type was identical, although the former exhibited a 6-fold larger response. Moreover, the kinetics of anthocyanin accumulation in continuous R were similar in the wild-type and hp-mutant seedlings, despite the latter accumulating 9-fold more anthocyanin. Since the properties of phytochrome are the same, the hp mutation appears to affect the state of responsiveness amplification, i.e. the same amount of Pfr leads to a higher response in the hp mutant. We therefore propose that the hp mutation is associated with an amplification step in the phytochrome transduction chain. Escape experiments showed that the anthocyanin synthesis after different light pretreatments terminated with a R pulse was still 50% FR reversible after 4–6 h darkness, indicating that the Pfr pool regulating this response must be relatively stable. However, fluence-rate response relationships for anthocyanin synthesis and hypocotyl growth induced by a 24-h irradiation with 451, 539, 649, 693, 704 and 729 nm light showed no or a severely reduced response in the au and au, hp mutants, suggesting the importance of PI in these responses. We therefore propose that the capacity for anthocyanin synthesis (state of responsiveness amplification) could be established by PI, while the anthocyanin synthesis is actually photoregulated via a stable Pfr pool. The Hp gene product is proposed to be an inhibitor of the state of responsiveness amplification for responses controlled by this relatively stable Pfr species.     

PHOTOREACTIVATION IN A phrB MUTANT OF Escherichia coli K-12: EVIDENCE FOR THE ROLE OF A SECOND PROTEIN IN PHOTOREPAIR

Abstract In Escherichia coli , the light-dependent repair of pyrimidine dimers in UV-irradiated DNA is now accepted as being due to enzymatic photoreactivation (PR) by a 50 kDa enzyme, photolyase (EC 4.1.99.3). The gene for this enzyme has been mapped at 16.2 min and designated phr . This gene was earlier described as phr B, another locus phr A having been proposed in association with PR. The relevance of the putative phr A gene has now been placed in doubt. The recent report of the discovery of a photoreactivating enzyme in Drosphila melanogaster . which specifically repairs pyrimidine (6–4) pyrimidone photoproducts ([6–4] photoproducts), and that E. coli does possess a protein with specific affinity for the (6–4) photoproduct, has cast new light on the prospective role of phr A in PR. We have determined the nucleotide sequence of the putative phr A gene, which suggests it codes for a protein of 38 kDa. When the putative phr A gene was cloned into an expression vector and transformed into a phr A phr B mutant of E. coli , a level of photorepair was observed, which could correspond to repair of (6–4) photoproducts.     

ISOLATION OF BLEPHARISMIN-BINDING 200 kDa PROTEIN RESPONSIBLE FOR BEHAVIOR IN Blepharisma

Abstract— The ciliated protozoan, Blepharisma, shows an avoidance reaction (step-up photophobic response) in response to light stimulation. A profile of a gel-permeation of a crude detergent-solubilized sample of the cells resulted in several red-colored fractions. Among these blepharismin-containing fractions, the fractions III-V did not contain amino acids. The peak of fraction II monitored by 580 nm absorbance was much smaller. A prominent peak appeared in fraction I, which contained a large amount of amino acids. The absorption spectrum of fraction I was well fitted to the action spectrum of the step-up photophobic response, although free pigment (blepharismin) also fitted. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of this fraction resulted in a thicker band corresponding to molecular mass of 200 kDa. These results suggest that the 200 kDa chromoprotein (blepharismin-protein complex) is responsible for the step-up photophobic response in Blepharisma. The absorption spectrum of free chromophore dissociated from the chromophore-protein complex was identical to free red pigment termed blepharismin. The absorption spectrum of the other fractions agreed with that of thin-layer chromatography-purified red pigment, indicating that the pigments contained in these fractions are free pigment dissociated from the chromophore-protein complex.     

PHOTOSYNTHETIC EFFICIENCY OF A PHYCOCYANIN-LESS MUTANT OF CYANIDIUM*

Abstract— 1. R-II is a u.v. induced mutant of cyanidium caldarium which lacks the major accessory pigment phycocyanin. 2. Loss of phycocyanin does not impair photosynthesis or the Hill reaction. 3. The action spectrum for the quantum yield indicates an efficiently operating photosynthetic mechanism which is shifted in peak efficiency toward longer wavelengths when compared to the wild-type spectrum. The red drop is also shifted toward the far red in R-II. 4. Although 30 per cent enhancement was obtained in wild-type Cyanidium, no enhancement was observed when phycocyanin was absent. 5. A pigment absorbing at 720 nm has been observed and may possibly represent a chlorophyll-phycocyanin complex.     

一种用于测试合成氨变换反应中汽气比的新方法

合成氨生产是一个复杂的、具有多变量、非线性的控制工艺过程。其中变换反应是一个受温度、压力、反应物料，甚至气候条件等因素影响的物理、化学过程。稳定而有效地控制与操作该过程显得十分重要，为此为了指导操作、节约蒸汽、稳定生产，我们开发研究了一种用于测试变换...     

REPAIR OF ULTRAVIOLET-IRRADIATED TRANSFORMING DNA IN A recA MUTANT OF Haemophilus influenzae

—Ultraviolet-irradiated transforming DNA was assayed on a wild-type strain of Haemophilus influenzae strain Rd, on an excision repair-deficient ( uvr-2 ) mutant, on a recombination repair-deficient ( recA4 ) mutant, and on a strain carrying both mutations. The donor DNA had a point mutation genetic marker ( strAl ) and a long nonhomologous plasmid-derived DNA segment inserted in the HP1 prophage. The shape of the inactivation curves suggested that only recombination was responsible for the inverse square root kinetics observed with excision repair-proficient recipients.     

OZONE EXPOSURE DECREASES UVB SENSITIVITY IN A UVB-SENSITIVE FLAVONOID MUTANT OF Arabidopsis

Abstract— The impact of sequential exposure to ozone (O₃) and UVB (290–320 nm) was studied using two genotypes of Arabidopsis thaliana differing in UVB sensitivity. The negative impact of UVB on dry matter production and photosynthetic pigments was absent in the ecotype Landsberg erecta (LER), while the negative impact of UVB was more pronounced when LER plants preexposed to O₃ were irradiated with UVB. However, the growth of tt5 plants (a mutant virtually incapable of synthesizing flavonoids) was significantly affected by the UVB exposures, while the impact of UVB was significantly counteracted when tt5 plants pre-exposed to O₃ were irradiated with UVB. These results suggest that pre-exposure to O₃ decreased sensitivity of tt5 but increased sensitivity of LER to UVB. Concentrations of UV-absorptive compounds were almost the same in plants exposed to UVB alone or sequentially to O₃ and UVB. Exposures of LER and tt5 to UVB enhanced both ascorbic acid and glutathione as well as their redox state compared to control plants. Pre-exposure to O₃ enhanced the total ascorbic acid and glutathione as well as the redox state of ascorbate and glutathione in tt5 but decreased the redox state in LER. Irradiation of plants pre-exposed to O₃ with UVB enhanced the redox state of ascorbate and glutathione slightly in tt5 but decreased it further in LER. The high redox state of ascorbate and glutathione in tt5 pre-exposed to O₃ would have protected plants from UVB and decreased their sensitivity to UVB in spite of their inability to synthesize flavonoids. The decreased redox state in O₃-exposed LER plants would have enhanced their sensitivity to UVB. These results suggest that O₃ influences plant response to UVB in environments enriched with both O₃ and UVB.     

BLUE AND WHITE LIGHT EFFECTS ON CHLOROPLAST DEVELOPMENT IN A SOYBEAN MUTANT

Phenotypic difference for chloroplast development between the normal green (CL1) and the Cy₉y₉ soybean mutant was observed when the plants were grown under 18W m^?2 white or blue light. Under these conditions the mutant soybean accumulated less Chi b, neoxanthin, carotene and less total pigment than the CL1 genotype. Chloroplasts of the Cy₉y₉ line were deficient in the LHP complex relative to that of chloroplasts from the normal soybean. Specific differences were noted between chloroplasts from plants grown under blue and white light. Accumulations of a 34 kD (PSII) and a 16–17 kD (PSI) membrane polypeptide were decreased by blue light in both soybean genotypes. Blue light induced a greater accumulation of a 32 kD (PSII) polypeptide than white light. Blue light reduced granal thylakoid stacking and increased the proportion of stroma thylakoids compared to those that developed under white light. PSI electron transport activity was stimulated by the blue light treatment more than that of PSII.     

PHOTOSENSORY BEHAVIOR OF A BACTERIORHODOPSIN-DEFICIENT MUTANT, ET-15, OF Halobacterium halobium

– Halobacterium halobium , strain ET-15, which does not contain detectable amounts of bacteriorhodopsin (BR) shows behavioral responses to UV and yellow-green light. Attractant stimuli. i.e. light-increases in the yellow-green range or light-decreases in the UV, suppress the spontaneous reversals of the swimming direction for a certain time. Repellent stimuli, i.e. light-decreases in the yellow-green range or light-increases in the UV, elicit an additional reversal response after a few seconds. Action spectra of both sensory photosystems, PS 370 and PS 565, were measured with attractant as well as with repellent stimuli. As in BR-containing cells, maximal sensitivity was always found at 370 nm for the UV-system and at 565 nm for the long-wavelength system. Fluence-response curves at 370 and 565 nm obtained with strain ET-15 and with a BR-containing strain show that the sensitivity of both photosystems is not reduced in the absence of BR. It is concluded that BR is required neither for PS 565 nor for PS 370. Instead retinal-containing pigments different from BR have to be assumed to mediate photosensory behavior.