583 



Jerome J, Wollien 



for a minute after an anaerobic suspension of Photo"bq.cterium 

 phosplaoreum was injected into the system in darluiess{21j, 



A light-catalyzed conversion of inor^^Jiic phospliate into la- 

 bile phospliate vas also observed over a 1 hr. period in a similar 

 anaerobic system containing 6 co-factors and adenosine monophos- 

 piiate^^-^^. The reaction vessels contained 2 ml of chloroplastin 

 ifith a chlorophyJJL concentration of about IO'^m, 20 \£:A of Mg ++30 

 nil of alpha ketoglutarate, 0.3 \£:i of riboflavin-5 -phosphate, 0.6 

 nil of menadione (Vitamin Ko) 2[s}'l of ascorbate, 5|ig of cytochrome- 

 c. 55 nil of adenosine monophosphate, and 4ng of inorganic phos- 

 phate. Tliese experiments were immediately repeated with the addi- 

 tion of glucose and hexokinase, and the glucose -6-phosphate form- 

 ed ■^•ra.s determined by triphospho-p^joridine nucleotide reduction at 

 ^kO m\x in the presence of glucose-6-phospliate dehydrogenase. In 

 this \iB.y, 80 to 90fj of the inorganic phosphate that disappeared 

 was accounted for as labile phosphate. The phospliate conversion 

 occujrring in dark controls vTas only 3 to kfo of that found in the 

 light. Whether all of the co-factors play a role in the reac- 

 tion is as yet \mkno\m. These results, however, do indicate that 

 some typical photos^Tathetic reactions can be observed with Euglena 

 chloroplastin. 



STRUCTURE AIID EIIERGY TRAI^FER 



The ordered fine structure for the photoreceptors has led to 

 the idea that they bear a close relationship to a solid state 

 system, exliibiting properties such as electronic energy transfer 

 or electronic charge transfer. Experiments have been carried out 

 \rlth monolayers of clilorophyll, chlorophyll plus p- carotene, or 

 B-carotene alone spread on various surfaces. Such sandwiched mo- 

 dels liave been demonstrated to be photoconductive^^^^'^SJ, Experi- 

 mental evidences including the electron spin resonance (ESR) ex- 

 periments and the semicpnduction and thermoluminescence studies 

 by Arnold and Cla-^rton^^^'', suggest that there is a photoconduc- 

 tive mechanism of energy transfer actively participating in the 

 cliloroplast. V/e have found that there is a temperatiire dependence 

 of conductivity in isolated chloroplasts and chloroplastin simi- 

 lar to the relationship found in semiconductors. Tliese experi- 

 ments indicate that there is an increase in conductivity to light 

 particularly in the region 660 m.[x, also that the conduction is 

 probably by ions, electrons, and holes ^2;?;, 



It will be remembered that in order to see the lamellae, the 

 chloroplasts are fixed with osmium tetroxide, potassiim dichro- 

 mate, potassium pemanganate, or other metal-containing ccmpoujid% 



