Chloroplasts table

The presence of added NaHCO gives a positive effect on the phosphorylation of the 25 kDa, but not the 27 kDa, apopolypeptide of LHC2. In the case of phosphorylation of thylakoid membranes (Table 1), the NaHCO increased phosphorylation of the 25 kDa polypeptide with 44Z compared with 4Z for the 27 kDa polypeptide. The same pattern was seen when phosphorylation was induced using intact chloroplasts (Table 2). 

Both of the two hybrids having the lowest Pn value, 65013 and 81136, had large starch granules in the chloroplasts (Table 1., Fig. l.a). The accumulation of starch is probably due to the absence of an efficient sink in these hybrids as 81136 does not tuberize and 65013 produces only swollen stolons (5). 

Measurements of temperature dependent galactolipid biosynthesis showed that frosthardened chloroplasts were about 3 times more active than unhardened chloroplasts (Table 1). The higher activity was found at all temperatures and was thus not due to a change in temperature optimum of the enzymes. 

Fatty acid analysis of total fatty acids synthesized in vitro by chloroplasts (Table 2) reveals the fact that, in all cases, more label is incorporated into unsaturated fatty acids (16 19c, 18 1,18 2, 18 3 and 20 1) than into saturated fatty acids (16 0 and 18 0). The ratio of saturated to unsaturated fatty acids in all lipid classes varies with the plant (Table 2) and with incubation conditions (unpublished data). 

Tobacco. In selectivity assays tobacco ATI discriminates aginast 16 0 in the synthesis of LPA (see Figure 1), and this bias is reflected here in the PA pool of chloroplasts (Table 3). In direct contrast to this obvious selectivity by ATI (and, again, possibly AT2) is the observation that the newly synthesized PG and DG pools from isolated tobacco chloroplasts are relatively enriched in di-saturated species in comparison with the PA pool. This indicates to us that the bias of AT 1 for 18 1 at sn-1 is partially overridden by a preference for di-saturated species by the headgroup enzymes. 

Cucumber. The situation in cucumber chloroplasts is similar to that in tobacco chloroplasts (Table 3). The upstream selectivity for 18 1 at the sn-1 position of PA is again partially overcome by a selectivity for di-saturated species by the headgroup enzymes. The molecular species composition of the PA pool would indicatea prior selection for either 18 1-ACPat ATI, and/or for 18 1-LPA by AT2. We cannot discriminate between these possibilities from the chloroplast experiments, but the competition experiments again show that cucumber ATI selects for 18 1-ACP in mixtures of acyl substrates. 

The Vepex process developed in Hungary (Table 9) involves disintegration of plant materials followed by double screw pressing to maximize juice production. Green chloroplastic protein is removed by direct steam-injection heat treatment at 82°C with the addition of flocculents and centrifugation. The white protein fraction is separated from the chlorophyU-free process juice by direct steam injection at 80°C, followed by centrifugation and drying (94). 

The pathway is depicted in Fig. 35. The Calvin cycle, taking place in the chloroplast stroma of plants, is a primary source of carbon for all organisms and of central importance for a variety of biotechnological applications. The set of reactions, summarized in Table VIII, is adopted from the earlier models of... 

It is probable that electrostatic component of resulting interactions on anion-anion distances is registered in such a way. In fact, the calculated value 0.83E practically corresponds to the experimental bond energy values during phosphorylation (first line in table 4) and free energy for ATP in chloroplasts (second line in table 4). 

Table II Inhibition of Hill Reaction in Spinach Chloroplasts...

It will be noted that in isolated spinach chloroplasts, one hardly needs to worry about making an inhibitor too hydrophobic i.e. optimal log P = 5.2 for the N,N-dimethyl- and 5.4 for the methoxymethyl-ureas. In contrast to the isolated chloroplast studies, one sees from a list of commercially successful herbicides for which log P values have been measured or calculated, (Table IV) that getting the herbicide to the chloroplast in the living plant places much greater restrictions on its hydrophobic-hydrophilic balance. Indeed, the average log P of this set is only 2.54. 

The objectives of the studies reported herein were to (a) compare the effects of a series of phenolic acids, coumarins, and flavonoids on whole chain electron transport and phosphorylation in Isolated plant chloroplasts and mitochondria and (b) identify specific sites of inhibition with polarographic and enzymatic techniques. Exploratory studies were conducted with the 20 compounds listed in Table I. The three glycosides are shown indented below the corresponding aglycones. Detailed studies were conducted with the six compounds, one representative member from each chemical family, designated with an asterisk. 

Table I. Inhibition of electron flow in isolated chloroplasts...

We first studied the changes in free sterols of leaves and chloroplasts of beans and spinach exposed to ozone ( ). We found (Table IV) that ozonated bean leaves and chloroplasts had 25% and 12% less free sterols respectively than bean leaves and chloro-... 

Table IV, Changes in free sterol content of whole tissue and chloroplasts of bean and spinach leaves exposed to ozone (50 pphm for 1 hr)...

In another experiment (Table V), the free sterol content of ozonated chloroplasts from beans was found to be 32% less and the content of sterol derivatives 37% more than that of non-ozonated chloroplasts. What happens to the free sterols (FS), sterol glycosides (SG) and acetylated sterol glycosides (ASG) can be seen in Table VI, In these experiments ( ) with whole leaves of beans, FS in the ozonated leaves was 21% less, SG 32% more, and ASG 41% more than in non-ozonated leaves. 

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