EFFECT OF BLUE LIGHT AND RED LIGHT ON THE CONTROL PEA LEAVES TO INCREASED FLUENCE RATES OF CHLOROPLAST ACCLIMATION OF LIGHT-GROWN PEA LEAVES TO INCREASED FLUENCE RATES

Abstract— We have investigated the possibility of the involvement of a blue light fluence-rate sensing photoreceptor in the light acclimation of chloroplast components in light-grown pea seedlings. Low lightgrown seedlings were acclimated for 2 days to either 20 or 200 μmol^m-2s-2 of white, blue-enriched, or broad-band red light. An increase in blue-enriched light fluence rate was more effective than that of red light in bringing about both inhibition of internode growth and the enhancement of the chlorophyll a/b ratio. Ribulose 1,5-bisphosphate carboxylase/oxygenase and cytochrome f protein levels, per unit cell, also increased more markedly (around two-fold) in response to an increase in blue light. The 23 kDa polypeptide of the oxygen-evolving complex and the light-harvesting chlorophyll d b protein of photosystem II apoprotein levels vaned under all wavelengths to a lesser extent, correlating with total protein levels or greening. These data are consistent with the hypothesis of a role for a blue photoreceptor in detecting low versus high fluence rate of light, and subsequently controlling the light acclimation responses. Nevertheless photosynthesis or other mechanisms of fluence-rate photoperception must also be involved.     

THE EFFECT OF RED AND FAR RED LIGHT ON CAROTENOID AND CHLOROPHYLL FORMATION IN PEA SEEDLINGS

Abstract— Treatment of etiolated pea seedlings with a short exposure to red light caused a stimulation of growth (size and dry wt production) and carotenoid synthesis during the following 48 hr compared with seedlings kept entirely in darkness.The effect is nullified by a following dose of far red light and thus the phenomenon is probably phytochrome-controlled.
Similar treatment with red light one hour before continuous illumination with white light tended to reduce the lag period for chlorophyll synthesis.Again a following dose of far red light reversed this response.     

THE EFFECT OF LEVULINIC ACID ON THE LIGHT INDUCED DEVELOPMENT OF PHOTOSYSTEM I AND II ACTIVITIES IN GREENING MAIZE LEAVES*

Photosystem I and Photosystem II activities were measured in chloroplasts isolated after 0–20 h illumination from etiolated maize leaves in which chlorophyll synthesis was specifically inhibited by levulinic acid. In control leaves not treated with levulinic acid, Photosystem I activity/chlorophyll developed rapidly during the first 2h in light, then fell off, and reached a constant level after 6h of illumination. In levulinic acid treated leaves, in which chlorophyll accumulation was inhibited up to 60%, a similar initial rise in Photosystem I activity was observed. However, the decrease in activity was much slower and continued for at least 20 h. The development of Photosystem I activity calculated on a leaf fresh weight basis was similar for control leaves or leaves treated with levulinic acid. This indicates that development of Photosystem I activity may not be related to chlorophyll accumulation during greening. Photosystem II activity/chlorophyll in leaves treated with or without levulinic acid increased similarly during the first 6h and then remained constant. Activity of Photosystem II per leaf fresh weight increased linearly, after the first h, for 20 h in the control leaves; in levulinic acid treated leaves this development was reduced by about 60%. Thus, development of Photosystem II activity can be related to chlorophyll accumulation. SDS gel electrophoresis of plastid membranes from control leaves illuminated for 12 h showed the presence of chlorophyll-protein complex I as well as Chl-protein 11; in the case of levulinic acid treated leaves only Chl-protein complex I was detectable, while Chl-protein complex II was markedly reduced.     

THE EFFECT OF RED AND FAR-RED LIGHT ON NUCLEIC ACID METABOLISM IN RYE SEEDLING SHOOTS

Abstract— The quantitative changes in the levels of RNA and DNA in shoots treated with red and/or far-red light are presented.
The results indicate that red light, but not far-red light, stimulated cell division. The changes in RNA are discussed in relation to the nature of the light treatment.     

MAGNESIUM ION EFFECTS ON CHLOROPLAST PHOTOSYSTEM II FLUORESCENCE AND PHOTOCHEMISTRY

Abstract. –Although there have been several reports that divalent cations, especially Mg²⁺, can significantly affect chloroplast photoprocesses, the molecular mechanism of cation interaction is not well understood. We have investigated the interaction of Mg²⁺with Photosystem II photoprocesses by studying cation effects on chloroplast fluorescence and the Hill reaction. Our results are summarized as follows.
1. Mg²⁺stimulation of background fluorescence (20–30%) saturates at about 0.5 mM Mg²⁺, while Mg²⁺stimulation of variable fluorescence (250%) saturates at about 2.5 mM Mg²⁺.
2. Addition of Mg²⁺to chloroplasts treated with 3-(3,4-dichlorophenyl)-1,1-dimethylurea or dithionite causes a doubling in the amount of total (background + variable) fluorescence.
3. Studies on chloroplasts in the presence of 2,6-dichlorophenolindophenol indicate that Mg²doubles the relative yield of variable fluorescence under light-limiting conditions.
4. Mg²causes large (70–120%) increases in the light-limited rate of the DCIP Hill reaction.
We interpret these results in terms of a model involving two components of chloroplast emission. Our analysis indicates that Mg²⁺increases the effective absorption cross section (size) of the pigment array associated with Photosystem II photochemistry.     

RUTHENIUM RED INHIBITION OF OXYGEN EVOLUTION AND SPECIFIC RELEASE OF THE EXTRINSIC 16 kDa POLYPEPTIDE IN A PHOTOSYSTEM II PREPARATION

The inhibitory effect of the dye ruthenium red was studied in photosystem II-enriched submembrane fractions. A number of distinct types of interaction were found, which differed in their concentration range and required incubation time. Ruthenium red instantaneously quenches the initial chlorophyll a fluorescence level (F₀) and the maximum fluorescence level (F_m) by enhancing radiationless deactivation in the chlorophyll light harvesting complex. Associated with this quenching of fluorescence is an instantaneous decrease in the quantum yield of oxygen evolution. Ruthenium red also inhibited the light saturated rate of oxygen evolution and the variable fluorescence, monitored 80 µs after a saturating excitation-flash. These inhibitions increased with incubation time and became greater than 50% within 5 min. Although ruthenium red was known to affect Ca²⁺ or Cl^? sites specifically, the inhibitory action was more pronounced than simple Ca²⁺ or Cl^? depletion. Incubation with ruthenium red for 5 min blocks the Z P680⁺ → Z⁺ P680 charge transfer reaction. Upon mixing with the photosystem II preparation, ruthenium red induced specific release of the extrinsic 16 kDa polypeptide associated with water-splitting without release of Mn. It is proposed that the inhibitor produces an ionic imbalance which alters the configuration of the donor side of photosystem II.     

LETTUCE SEED GERMINATION: EFFECTS OF HIGH TEMPERATURE AND OF REPEATED FAR-RED TREATMENT IN RELATION TO PHYTOCHROME

Abstract— At 37°C the active form of phytochrome in lettuce seed cannot function to promote subsequent germination. This effect of high temperature is distinct from thermal acceleration of dark reversion from the active form of phytochrome to the inactive form, and may be due to reversible denaturation of phytochrome.
Repeated brief irradiations with far-red light inhibit subsequent germination in the whole seed, whereas a similar irradiation regime results in a strong enhancement of the development of growth potential (ability to expand against an externally-imposed osmotic restraint) in the excised axial portion of the seed. A possible explanation for these two opposing results, in volving two different pigment systems with effective loci in different parts of the seed, is suggested.     

EFFECTS OF PHOTOSYSTEM II INHIBITORS ON ELECTRON PARAMAGNETIC RESONANCE SIGNAL II OF SPINACH CHLOROPLASTS

Abstract— In isolated spinach chloroplasts the light-induced electron paramagnetic resonance signal (signal II) associated with the oxygen evolving photosystem (photosystem II) decays slowly and incompletely in the dark. Tris-washing, hydroxylamine, or carbonylcyanide m -chlorophenylhydrazone (CCCP) enhance the decay of signal II, which can still be induced by red (645 nm) but not by far-red (735 nm) radiation. Although 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) alone has no effect on signal II, it blocks the induction of signal II in the presence of hydroxylamine or CCCP. These data suggest that signal II is an indicator of an oxidized intermediate on the water-splitting side of photosystem II.     

月季花红色素的提取及稳定性的研究

一．引言月季，别名月月红，月季花（ＲｏＳａＣｈｉｎｅｎｓｉｓＪａｃｑ），属蔷薇科，蔷薇属，从每年的３月到１０月蓓蕾续放，开花不绝，现广泛栽培，主要分布于河北、陕西、山西等地。月季花主要成分为萜醇类化合物［１］，花、根及叶均可入药，内服可治妇女病，外用...     

EFFECTS OF N-PHENYLIMIDE S-23142 AND N-METHYL MESOPORPHYRIN IX ON THE SYNTHESIS OF THE PHYTOCHROME CHROMOPHORE IN PEA EMBRYONIC AXES

Abstract Treatment of imbibed embryonic axes taken from seeds of Pisum sativum with N-phenylimide S-23142, a herbicide that has been suggested to inhibit protoporphyrin synthesis, or with N -methyl mesoporphyrin IX, an inhibitor of the iron chelatase for heme, resulted in a significant decrease in the amount of spectrophotometrically detectable phytochromc in the axes in both cases. However, the amount of immunochemically detectable phytochrome was not affected by either treatment. If S-23142 inhibits the synthesis of protoporphyrin IX in pea, it appears that the conversion of protoporphyrinogen IX to protoporphyrin IX is involved in the biosynthesis of the phytochrome chromophore. The conversion of protoporphyrin IX to heme (Fe-protoporpbyrin) also appears to be a step in the biosynthesis of the chromophore, since N -methyl mesoporphyrin IX prevented the synthesis of spectrophotometrically detectable phytochrome but did not affect the magnesium chelatase activity required for the synthesis of chlorophyll in pea embryonic axes. The results suggest that protoporphyrinogen IX, protoporphyrin IX and heme are intermediates in the biogenesis of the phytochromc chromophore. The pathway to phytochromobilin might become fixed after protoporphyrin IX, being directed toward the Fe branch for heme rather than to the Mg branch for chlorophyll.     

PHOTODYNAMIC EFFECTS ON CELLS IN VITRO EXPOSED TO HEMATOPORPHYRIN DERIVATIVE and LIGHT

Abstract Several effects of hematoporphyrin derivative (HpD) and light on NHIK 3025 cells in vitro were studied. The treatment resulted in a partly repairable reduction of the rate of thymidine incorporation into DNA, a division delay, a reduced rate of protein synthesis, a reduced rate of active cellular uptake of α-aminoisobutyrate, a reduction in the colony-forming ability and an increased permeability of the cell membrane to chromate. Thymidine incorporation was by far the most sensitive parameter studied. However, comparison of the photodynamic effects after 1 and 18 h incubation with HpD prior to irradiation indicated that neither the reduced rate of DNA synthesis nor any of the other observed effects was the main primary cause of cell inactivation under all conditions. Several of the effects, such as increased permeability of the cell membrane to chromate, reduction in the rate of protein synthesis and reduction in the rate of repair of the damage to the mechanism of DNA synthesis, were clearly of secondary nature. When seen in relation to cellular survival, membrane damage was more important after short incubation times with HpD than after long incubation times.     

稀土在烤烟植株中的分布及其对烟叶化学成份影响的研究

作为一种生理活性物质,稀土施用在烟草上平均增产11％,上中等烟比例提高7．53％左右,稀土应用于烤烟大部分限于田间试验,缺深入的机理研究^[2-4]。本试验用低浓度混合硝酸稀土喷施烤烟叶面,研究了稀土在烤烟植株中的含量,分布及土壤中可溶态稀土的变化情况及稀土对烟叶化学成份的影响,旨在为烤烟施用稀土提供科学依据。     

THE ANTAGONISTIC EFFECTS OF TETRAHYDRO-PROTOBERBERINES ON DOPAMINE RECEPTORS: ELECTROPHYSIOLOGICAL STUDIES

Tetrahydroprotoberberines (THPBs), including (-)-stepholidine ((-)-SPD), (-)-tetrahydropalmatine ((-)-THP) and tetrahydroberberine (THB), have been demonstrated to be a new class of DA antagonists in biochemical and neuropharmacological studies. In this paper, the antagonistic action of THPBs was examined by means of single unit recording from nigral DA neuron in chloral hydrate-anesthetized and gallamine-paralyzed rats. Intravenous injection of these compounds could promptly and completely reverse the inhibition of the spontaneous firing induced by DA agonist apomorphine (APO) in a dose-dependent way. Pretreatment with (-)-SPD, (-)-THP or THB could significantly reduce the inhibitory effect of APO and shift the dose-action curve to the right. Besides, the compounds could increase the spontaneous firing of DA neurons. The above results not only strongly support the conclusion that (-)-SPD, (-)-THP and THB are DA antagonists, but also demonstrate that one of their blocking sites is at somatodendritic DA     

EFFECTS OF INTERFACIAL POLYUREA FILM ON THE STABILITY OF OIL IN WATER EMULSIONS

The stability of oil in water emulsions containing a triisocyanate soluble in the oil phase was investigated. The oil component was either di-n-butyl phthalate (DBP) or a mixture of DBP with liquid paraffin. The time required for the average size parameter to reach a constant value was studied. It was found that the polyurea film produced by an interfacial polymerization reaction between water and a triisocyanate contributed to make the stable emulsions. The effects of drop size, temperature, polarity of oil phase, triisocyanate concentration, and mechanical stirring on the stability of the emulsions were established in this study. The film thickness at the point where the average size parameter reached a constant value was found to be of the order of 0. 002 ～ 0. 004μ.     

催化柴油中的酚类化合物及其对柴油安定性的影响

催化裂化柴油用１０％的碱－醇（５：１体积）萃取,得到了０．５～０．８Ｗ％（相对柴油）的酚的混合物。通过色质分析,鉴定出了６９种酚,其结构比文献报道的从催化柴油中分离的酚的结构要复杂得多。这些酚的混合物对柴油的颜色和沉渣有明显的影响。元素分析表明其中还含有硫氮化合物。     

不同添加物和制备方式对Al2O3热稳定性的影响

通过水溶液成胶和丙三醇络事助成胶制备了不同的结构的γ－Ａｌ２Ｏ３,研究了Ｌａ,Ｓｉ,Ｂａ以及Ｌａ,Ｓｉ和Ｌａ,Ｂａ双组分改性对它们结构热稳定的作用,讨论了改性元素的引入方式及硅铝比的影响。结果表明,丙三醇络合助成胶能明显提高Ａｌ２Ｏ３的比表面积和孔径,并能显著改善Ａｌ２Ｏ３的热稳定性。     

INHIBITION OF ELECTRON TRANSPORT IN CHLOROPLASTS BY CHAOTROPIC AGENTS AND THE USE OF MANGANESE AS AN ELECTRON DONOR TO PHOTOSYSTEM II*

Abstract— Incubating spinach chloroplasts with various chaotropic agents results in inhibition of photosynthetic electron transport between water and Photosystem II similar to the inhibition caused by washing chloroplasts with a high concentration of Tris buffer. Partial restoration of NADP photoreduction and fluorescence of variable yield is achieved by adding hydroquinone or Mn²⁺, either of which donates electrons to Photosystem II in the inhibited chloroplasts. The inhibitory treatments cause the release of Mn from its bound state in the chloroplast, thus allowing the measurement of the ESR signal of Mn²⁺. The ESR measurement is used to follow the photooxidation of Mn²⁺ as it donates electrons to photosystem II.     

THE EFFECTS OF ULTRAVIOLET C ON in vitro NUCLEOSOME ASSEMBLY AND STABILITY

Abstract The effects of ultraviolet C (UVC) irradiation on nucleosome assembly and its stability were investigated quantitatively using an in vitro nucleosome assembly system comprising a plasmid DNA of pBR322 and core histones isolated from rat ascites hepatoma cells. Nucleosomal formation was estimated by analyzing the resulting DNA supercoils. When UVC-irradiated (3000 J/m²) DNA was used as a substrate for the nucleosome assembly system, the nucleosomal formation efficiency was reduced by half compared with nonirradiated DNA. On the other hand, when the reconstituted nucleosomes (minichromosomes) on the nonirradiated DNA were irradiated with UVC (3000 J/m²), about half each were disrupted and retained. These results indicate that it is difficult for UV-damaged DNA regions to supercoil around the histone octamers to form nucleosomes and that the histone octamers in the UV-damaged nucleosomes tend to be dissociated from DNA.