Effects of Ethephon on Aging and Photosynthetic Activity in Isolated Chloroplasts

Hyung T. Choe; Morris Whang

doi:10.1104/pp.80.2.305

Investigations on a Galvanic Cell Driven by Photosynthetic Electron Transport

Zeitschrift für Naturforschung C ◽

10.1515/znc-1978-5-614 ◽

1978 ◽

Vol 33 (5-6) ◽

pp. 392-401 ◽

Cited By ~ 25

Author(s):

Wolfgang Haehnel ◽

Adelheid Heupel ◽

Dorothea Hengstermann

Keyword(s):

Electron Transport ◽

Open Circuit Potential ◽

Photosynthetic Activity ◽

Photosynthetic Electron Transport ◽

Open Circuit ◽

Galvanic Cell ◽

Platinum Electrodes ◽

High Effectiveness ◽

Electron Carriers ◽

Isolated Chloroplasts

Abstract A light-driven galvanic cell was constructed making use of the photosynthetic activity of isolated chloroplasts. Artificial mediators managed the transfer of electrons from the endogenous electron carriers to the platinum electrodes in each of the joined half-cells. In one the mediators were reduced by electrons originating from water. In the other the mediators were oxidized by photosystem I in the presence of an autoxidizable electron acceptor. The redox potential in the single half-cells has been studied as a function of the lipophilicity of the mediators and their concentration. Further more different autoxidizable acceptors and different treatments of the chloroplasts were investigated. The combined half-cells were separated by an ultrafiltration membrane. Upon illumination the system gave rise to an open circuit potential of up to 220 mV. This battery was charged with rates as high as photosynthetic electron transport rates. The results are discussed with respect to the arrangement of the cell and the properties of the components for high effectiveness and maximal potential differences.

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Photosynthetic activity of isolated chloroplasts from Euglena gracilis

Planta ◽

10.1007/bf00385499 ◽

1982 ◽

Vol 154 (1) ◽

pp. 70-75 ◽

Cited By ~ 10

Author(s):

Peter Sch�rmann ◽

Willam Ortiz

Keyword(s):

Euglena Gracilis ◽

Photosynthetic Activity ◽

Isolated Chloroplasts

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Ascaris haemoglobin as an indicator of the oxygen produced by isolated chloroplasts

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1949.0026 ◽

1949 ◽

Vol 136 (883) ◽

pp. 281-290 ◽

Cited By ~ 5

Keyword(s):

Photosynthetic Activity ◽

Oxygen Affinity ◽

Dilute Solution ◽

Cellular Activity ◽

Extreme Resistance ◽

Leaf Extracts ◽

Mammalian Muscle ◽

Blood Haemoglobin ◽

Isolated Chloroplasts

A technique for using haemoglobin as an indicator of oxygen produced by the photosynthetic activity of green leaves was first described by Hoppe-Seyler 1879). The method has been used with notable success by Hill (1937, 1939) and by Hill & Scarisbrick (1940) in their observations on the sub-cellular activity of isolated phloroplasts. The quantities of oxygen evolved in their experiments were small, and since the sensitivity of measurement was dependent upon the affinity of the haemoglobin for oxygen, it was desirable to select a haemoglobin having as high an oxygen affinity as possible. Hill (1936), however, had shown that muscle haemoglobin in dilute solution has a greater affinity than the blood haemoglobin of the same mammal. Thus at pH 8 and 19°C he found ox muscle haemoglobin to be half saturated at an O 2 pressure of 0.7 mm. compared with 1.8 mm. for ox blood haemoglobin under the same conditions. Using muscle haemoglobin as indicator, Hill (1939) was able to show that illuminated chloroplasts in presence of leaf extracts evolve oxygen to a pressure of 1 mm. Hg and in presence of ferric oxalate to a pressure of 4 mm. Hg. Haemoglobins are now known which have oxygen affinities higher than that of mammalian muscle haemoglobin. In particular it has been shown that Ascaris lumbricoides, a nematode parasitic in the pig, contains two haemoglobins remarkable for their extreme resistance to deoxygenation when they are equilibrated in vacuo (Davenport 1949). Because of this property the standard methods for the determination of the oxygen equilibrium curves could not be used. Hill (1939) had used a haemoglobin of known oxygen affinity to measure the tensions of oxygen produced by illuminated chloroplast systems. The object of the present paper is to compare the response of ox muscle haemoglobin and the Ascaris haemoglobins to oxygen produced photochemically under standard conditions and thus to obtain an indication of the relative affinities of the haemoglobins.

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Immobilization of chloroplasts from grass within a silica matrix synthetized by HIPE method

MRS Advances ◽

10.1557/adv.2020.46 ◽

2020 ◽

Vol 5 (14-15) ◽

pp. 727-733

Author(s):

Andrea Vaca-Oviedo ◽

Jérémy Causse ◽

Alicia Sommer-Márquez

Keyword(s):

Fluorescence Spectroscopy ◽

Photosynthetic Activity ◽

Environmental Problem ◽

Negative Impact ◽

Silica Matrix ◽

Silica Monolith ◽

Internal Phase ◽

Chlorophylls A And B ◽

Vis Spectroscopy ◽

Isolated Chloroplasts

ABSTRACTThe deficient disposition of the pruning waste, from grass (Poaceae), has been converted into a considerable environmental problem since it is discarded in common garbage dumps. As a result, gases and lixiviates are generated producing a negative impact on the environment. This project takes advantage of these residues to isolate their chloroplasts, with the aim of subsequently developing bioreactors that absorb CO2. The encapsulation of grass chloroplasts into silica monolith with a hierarchical texture, using high internal phase emulsion (HIPE) method was carried out. The isolated chloroplasts were analysed by UV-Vis spectroscopy to estimate the amount of chlorophylls a and b present in the grass. Moreover, the synthesized samples were characterized by fluorescence spectroscopy for monitoring their photosynthetic activity, having an activity up to at least 90 days.

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