Chloroplasts chlorophyll content

The marker enzymes used in this experiment are as follows vanadate-sensitive H+-ATPase (plasma membrane), nitrate-sensitive H+-ATPase or pyrophosphatase (tonoplast), TritonX-100 stimulated-UDPase or IDPase (Golgi complex), antimycin A-insensitive NADPH cytochrome c reductase (ER), and cytochrome c oxidase (mitochondria inner membrane). NADH cytochrome c reductase activity is found to be 10 times higher than NADPH cytochrome c reductase activity. Chlorophyll content can be measured as the chloroplast marker. The chlorophyll content is calculated by the following equation. Before measurement, auto zero is performed at 750 ran. 

Reaction of 232 with 4-substituted l,3-oxazol-5(4/7)-one 247 led to diacylhydrazines 248 or to imidazole derivatives 249 depending on the reaction temperature (Scheme 24). l,2,4-Triazole-3-thione 250 was obtained by a two-step sequence from 232 with phenyl isothiocyanate and subsequent base-catalyzed cyclization of thiosemicarbazide 251. The effects of hydrazones 241-246 on inhibition of photosynthetic electron transport in spinach chloroplasts and chlorophyll content in the antialgal suspensions of Chlorella vulgaris were investigated <2005CEC622>. 

Chloroplasts will be isolated by careful extraction of spinach leaves, using tricine buffer containing sucrose. The crude extract contains both whole and fragmented chloroplasts, but both contain all the necessary photosyn-thetic components and are capable of photophosphorylation. The preparation described in this experiment retains almost all of the chlorophyll in the chloroplasts. The total chlorophyll content of the chloroplasts will be determined by extracting the pigment with aqueous acetone and measuring the absorption at A. = 652 nm. The chlorophyll concentration is calculated according to Equation E9.3 (Arnon, 1949),... 

B 8. A student in the lab completes part B of this experiment to measure the chlorophyll content of the chloroplast preparation. The final A652 of the 80°/o acetone extract was 0.13. What is the concentration of chlorophyll in mg/mL in the chloroplast preparation ... 

D. Arnon, Plant Physiol. 24, 1-15 (1949). Determination of chlorophyll content of chloroplasts. 

A student m the lab completes part B of this experiment to measure the chlorophyll content of the chloroplast preparation. The final... 

Chloroplasts isolated from both vegetative and reproductive fronds exhibited similar trends in PS to varying PPFD and chlorophyll content within the electrode vessel. Typical light saturation curves are J.llujtrated in Figure 1. Maximum net PS occurred a1 60 Mmol m s (PPFD) for a j lorcphyll content of 25 Mg cm as opposed to 250 Mmol s (PPFD) for a... 

Some authors(1) concluded that photosynthesis at low Fw was more limited by the loss of chloroplast activity than by increased difussive resistance. RBPC activity decreased in bean and cotton plants at water stress(2)(3) (4). PEPC and RBPC activities decreased at water stress in barley plants(5). In mesophyll cells from bean and tomato plants there was decreased in CO2 fixation at fairly low osmotic potentials which simultaneous with stomatal closure(6). Recently it was reported(7) that in soybean leaves a non stomatal limitations of leaf photosynthesis under drought stress conditions appears to be due in part to a reduction in the in vivo activity of RBPC. On the other hand it has been reported that chlorophyll content (8) (9) (10) shows alterations due to water stress. In the present work we pretend to compare the responses of carboxylase activities and chlorophyl content to water deficit in two maize hybrids (Ci ) (CPB2 and CPB8), two tomato cultivars (C3) (Pera Quibor, PQ and Rio Grande, RG) and two bean cultivars CC3)(Tacarigua,T and VUL-73-401,V). 

All these factors are important for the development of plant cell cultures. For example, cultures of Lupinus polyphyllus only synthesize alkaloids when kept in the light and alkaloid content is correlated with chlorophyll content. This may be explained by a better supply of lysine (formed in the chloroplasts), the fact that the enzymes of alkaloid biosynthesis have a pH optimum of about pH 8, which is created in the chloroplast stroma only in the light, and that the enzymes are subject to activation by reduced thioredoxin which is generated only in the light (Wink, 1987). The alkaloids of Peganum harmala, which are formed in the roots of the plant, act in an opposing manner. Cultures maintained in the light fail to produce the alkaloids, whereas those kept in the dark synthesize harman alkaloids (Barz and Hiisemann,... 

Moreover, chloroplasts exhibiting different photosynthetic activities differed, as expected, with respect to their chlorophyll content. Whereas chloroplasts with photosystem I and photosystem II activity and normal grana stacking contained a very high chlorophyll portion in their lipids. 

Fig. 26. Changes in the susceptibility of different chloroplast-membrane proteins of C. rein-hardi y-1 to trypsin digestion during the greening process. Continuous line, untreated membranes dashed line, trypsinized membranes. Bottom membranes from dark-grown cells (1.4 fig chlorophyll/10 cells). Center membranes from cells greening in the presence of chloramphenicol (200 /ig/ml), chlorophyll content, 3.8 Mg/10 cells. Top membranes from control greening cells (14.1 Mg chlorophyll/10 cells). Note the change in sensitivity of peaks I, III, and IV. (For experimental details, see ref. 65.)...

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