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371.
An interaction between the lozenge gene and the suppressor of forked gene of Drosophila melanogaster has been investigated both spectrophotometrically and electrophoretically. The nature of this interaction is such that certain lozenge alleles appear to be phenotypically suppressed while others are enhanced or unaffected, and the results reported demonstrate that the effect can clearly be observed at the biochemical level. Earlier observations have suggested that the suppressor of forked gene codes for a ribosomal protein, and this hypothesis is discussed.These studies were supported by USPHS Grants GM-18485 and GM-20361 to P. D. S. P. D. S. is a recipient of USPHS Research Career Development Award GM-70758. 相似文献
372.
The activities of phenolase, peroxidase, cytochrome oxidase, catalase and superoxide dismutase, as well as the levels of lipid peroxides, were measured in plerocercoids of S. solidus taken from the body cavity of the fish (unactivated) and in plerocercoids which had been cultured in vitro, either under air, or under 95% N2, 5% CO2. When cultured anaerobically, the activities of phenolase, peroxidase and cytochrome oxidase all increased dramatically. Aerobically, only phenolase activity increased. Lipid peroxide levels and superoxide dismutase activity was similar at all stages and catalase could not be detected. It is suggested that the increased activity of oxidative enzymes in anaerobically cultured worms is an attempt to compensate for the reduced environmental pO2. 相似文献
373.
Gianantonio Battistuzzi Marzia Bellei Alan Leonardi Roberta Pierattelli Ariel De Candia Alejandro J. Vila Marco Sola 《Journal of biological inorganic chemistry》2005,10(8):867-873
The thermodynamic parameters for reduction of the type-1 (T1) copper site in Rhus vernicifera and Trametes versicolor laccases and for the derivative of the former protein from which the type-2 copper has been selectively removed (T2D) have
been determined with UV–vis spectroelectrochemistry. In all cases, the enthalpic term turns out to be the main determinant
of the E
o′ of the T1 site. Also the difference between the reduction potentials of the two laccases is enthalpy-based and reflects
differences in the coordination features of the T1 sites and their protein environment. The T1 sites in native R. vernicifera laccase and its T2D derivative show the same E
o′, as a result of compensatory differences in the reduction thermodynamics. This suggests that removal of the type-2 (T2)
copper results in modification of the reduction-induced solvent reorganization effects, with no influence in the structure
of the multicopper protein site. This conclusion is supported by NMR data recorded on the native, the T2D, and Hg-substituted
T1 derivatives of R. vernicifera laccase, which show that the T1 and T2/T3 sites are largely noninteracting. 相似文献
374.
Daizy R. Batish Harminder Pal Singh Mansimran Kaur Ravinder Kumar Kohli Surender Singh Yadav 《Acta Physiologiae Plantarum》2008,30(3):401-405
Caffeine (1,3,7-trimethylxanthine), a purine alkaloid found naturally in over 100 plant species, has recently been viewed
as a safe chemical for management of pests including molluscs, slugs, snails, bacteria, and as a bird deterrent. It possesses
phytotoxicity against plant species, yet the mechanism of action is lacking. A study was conducted to determine the effect
of caffeine on the rooting of hypocotyl cuttings of mung bean (Phaseolus aureus) and the associated biochemical changes. At lower concentrations (<1,000 μM) of caffeine, though rooting potential was not
affected, yet there was a significant decrease in the number of roots and root length. At 1,000 μM caffeine, there was a 68%
decrease in the number of roots/primordia per cutting, whereas root length decreased by over 80%. However, no root formation
occurred at 2,000 μM caffeine. Further investigations into the biochemical processes linked to root formation revealed that
caffeine significantly affects protein content, activities of proteases, polyphenol oxidases (PPO) and total endogenous phenolic
(EP) content, in the mung bean hypocotyls. A decrease in rooting potential was associated with a drastic reduction in protein
content in the lower rooted portion, whereas the specific activity of proteases increased indicating that caffeine affects
the protein metabolism. Activity of PPO decreased in response to caffeine, whereas EP content increased significantly indicating
its non-utilization and thus less or no root formation. Respiratory ability of rooted tissue, as determined through TTC (2,3,5-triphenyl
tetrazolium chloride) reduction, was impaired in response to caffeine indicating an adverse effect on the energy metabolism.
The study concludes that caffeine interferes with the root development by impairing protein metabolism, affecting activity
of PPO (and thus lignification), and EP content, which are the crucial steps for root formation. 相似文献