Recent life changes and outcome of prolonged competitive stress

To test the predictive utility of subjects' recent life changes with regard to outcome of prolonged competitive stress, the authors studied racers (N = 25) in a long distance Alaskan sled race, the Iditarod. Rank order correlations between subjects' 1-year life change units (LCU) total and adjusted place of finish proved significant by both Kendall's and Spearman's Test. Thus, lowe LCU scores correlated with better performance and higher scores with poorer performance. Differences between subgroupings of the racers are considered. The work suggests that the usefulness of recent life changes assessment may be extended beyong physical illness, particularly in the study of response and adaptation to prolonged stress.

Plastid development in primary leaves of Phaseolus vulgaris. Development of plastid adenosine triphosphatase activity during greening

The etioplasts of dark-grown bean leaves showed ATPase (adenosine triphosphatase) activity which had a pH optimum of 8.5, was stimulated by dithiothreitol and unaffected by light-triggering. Bean chloroplasts showed a low activity of dark-induced ATPase with a pH optimum of 8.5 and a substantial amount of light-triggered activity with a pH optimum of 8.0. The light-triggered activity depended on dithiothreitol and Mg2+ and was promoted by phenazine methosulphate. Light-triggered ATPase activity was completely inhibited by 20mum-dicyclohexylcarbodi-imide. Etioplasts developed light-triggered ATPase activity in response to 30 min illumination of the etiolated leaves. During the 48 h of light-induced greening of dark-grown leaves there was a 70% increase of the chloroplast ATPase activity found after light-triggering and a 30% fall in the dark-induced activity, both expressed on a per leaf basis. As the larger part of these changes occurred during the first 30 min of illumination, it is concluded that most or all of the chloroplast ATPase was present in the etioplast, a conclusion identical with that of Lockshin et al. (1971) for maize. During 48 h of greening there was a tenfold increase in the amount of thylakoid membrane in the leaf together with an 83% fall in the ATPase activity per m2 of thylakoid membrane, measured after light-triggering.

Isolation of Drugs and Drug Metabolites from Biological Fluids by Use of Salt-Solvent Pairs

Simple rapid procedures based on salt-solvent pairs have been developed for the isolation of drugs and drug metabolites from urine, plasma, and breast milk. The best overall recovery of drugs (84-104%) was obtained by using ammonium carbonate—ethyl acetate extraction. Internal standards were added to the biological samples before the isolation procedure was begun; standards labeled with stable isotopes were preferred. The isolated drugs were quantitated by selective ion detection, with use of an LKB 9000-PDP 12 in electron impact mode, a Finnigan 1015-PDP 8/1 in chemical ionization mode, and an atmospheric pressure ionization mass spectrometer. Sensitivity of detection was in the nanogram to picogram range.

Plastid development in primary leaves of Phaseolus vulgaris: The light-induced development of the chloroplast cytochromes

Etioplasts obtained from the primary leaves of dark-grown bean plants contained cytochromes f, b-559LP and b-563 in a molar ratio of approximately 1.0:2.0:1.5. On illumination of the plants there was a lag of between 10 and 15 h before these cytochromes increased in amount, but after 48 h they had increased from 6- to 10-fold on a per plastid basis. The presence of cytochrome b-559HP in the plastids was first detected after 15 h of illumination, which coincided with the commencement of grana formation and the onset of a number of photosynthetic reactions in the greening leaves. After 48 h of illumination the molar ratio for cytochromes f, b-559HP, b-559LP and b-563 was 1.0:1.2:2.8:2.6.Agranal chloroplasts formed by the exposure of dark-grown plants to intense light flashes contained high amounts of cytochromes f, b-559LP and b-563 but cytochrome b-559HP could not be detected.As the light-induced formation of cytochromes f, b-559LP and b-563 was substantially inhibited by D-threo chloramphenicol, but not by the L-threo isomer, it seems likely that their formation was dependent on 70S ribosomes. Both chloramphenicol isomers gave plastids which lacked cytochrome b-559HP.

The Relation between Photophosphorylation and Delayed Light Emission in Chloroplasts

One millisecond delayed light emission has been studied in isolated coupled lettuce (Lactuca sativa var. romaine) chloroplasts. Delayed light emission was increased upon addition of ferricyanide or 2,3,5,6-tetramethyl-p-phenylene diamine. In the presence of ferricyanide, the magnitude of the signal was increased by the addition of ADP (in the absence of orthophosphate), ATP, DI0-9, or phlorizin. The signal was also increased by the addition of NaCl and by the addition of NH(4)Cl in the presence of a high NaCl concentration. The signal of delayed light emission was decreased by the addition of gramicidin, valinomycin, and by the addition of NH(4)Cl in the presence of a low NaCl concentration.Phosphorylation, whether started by addition of ADP or by addition of glucose plus hexokinase plus ATP, caused a significant decrease in delayed light emission. It was concluded that the magnitude of delayed light emission reflects the size of the proton motive force across the thylakoid membrane. Calibration of delayed light emission by creating KCl gradients indicated that the value for the electrochemical potential gradient for H(+) in the presence of ferricyanide was at least 155 millivolts decreasing to 134 millivolts after the onset of phosphorylation.