摘要:

Résumé—La photocroissance des coléoptiles d'avoinein vitroest contrôlée par le phytochrome. Une thérie est proposée suivant laquelle ce pigment est sensibilisé par les pigments photosynthétiques des c

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1966.tb05778.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

Abstract—Measurements of the redox potential of the chemiluminescent compound 10,10′ dimethyl‐9,9′ biacridylium nitrate (‐0.093 V) show that it is thermodynamically possible to reduce it with hydrogen peroxide or with ammonium hydroxide in alkaline solutions at equilibrium concentrations sufficiently high to account for the observed chemiluminescence. Reduction of the compound with ammonium hydroxide takes place much more slowly than the corresponding reaction with hydrogen peroxide so that when both redox couples (O2/H2O2and N2H4/NH4OH) are present the hydrogen peroxide couple predominates if oxygen is supplied. It was shown that interference with the oxygen supply or its partial removal with nitrogen brings about an increase in chemiluminescence intensity in NH4OH while increasing the concentration of oxygen diminished the intensity.5‐amino 2,3 phthalazine 1,4 dione (luminol) also appears to undergo a reduction following a two step oxidation. This is shown by the fact that when oxygen was supplied the chemiluminescence intensity was found to be directly proportional to the OH‐concentration while a typical titration curve with pK11.7 is exhibited by the intensity when the oxygen supply is limited in mixtures of luminol and peroxydisulfate. The peroxide presumably arises in the first oxidation step. Amino peroxyphthalic anhydride is suggested as an intermediate which is reduced to the aminophthalate ion, the presumed emitter in the chem

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1966.tb05779.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

Abstract—The action spectrum and dose‐rate dependence for photoreactivation of mutation to prototrophy in late‐lag‐phase cultures ofEscherichia coliH3r30 (which lacks active photo‐reactivating enzyme) are roughly similar to those forphotoprotectionfrom killing in other strains. It is suggested that photoreactivation of this mutation in H/r30 is an indirect effect, similar in mechanism to photoprotection. The action spectrum and dose‐rate dependence for photoreactivation of mutation to prototrophy in late‐lag‐phase cultures ofE. coliH3r30‐R (which possesses active photoreactivating enzyme) are roughly similar to those forphotoreactivationof killing in most other strains. It is suggested that photoreactivation of this mutation in H/r30‐R is a direct effect at long wavelengths, but that there is an indirect component at short wavelengths. A quite different interpretation of these data is noted. Finally, it is found that, under the conditions of these experiments, indirect photoreactivation of killing in H/r30 and H/r30‐R i

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1966.tb05780.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

Abstract—Trypsin inactivated by u.v. radiation, gamma radiation, visible radiation in the presence of sensitizing dyes, and autolysis, was examined by the method of disc electrophoresis. Untreated Worthington twice crystallized salt‐free trypsin separated into four bands which moved toward the cathode; the main band, which had the greatest mobility, contained all of the detectable tryptic activity. The next most mobile band has been assumed to be a chymotrypsin contaminant. The other two bands are of unknown nature. A progressive loss of all the bands was observed when the enzyme was inactivated by those procedures which produce a ‘damaged’ class of trypsin molecules, i.e. flavin‐sensitized photooxidation, autolysis, and treatment with u.v. and gamma radiation. No loss of the main band was observed during photoinactivation with methylene blue and eosin Y as sensitizers. In this latter case, it is postulated that the trypsin inactivation products must be of such a nature that the net charge and conformation of the protein is not greatly changed, thus permitting all of the protein to remain in the same band during electr

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1966.tb05781.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

Abstract—The quenching constant for the iodide quenching of the fluorescence of riboflavin phosphate was measured at pH 5 and at pH 8. The value of the constant at the lower pH (where the phosphate group is unionized),k‘= 23 M‐1was independent of the ionic strength, μ. The ratiok“/k’= f(k”the quenching constant at pH 8, where the phosphate group carries a single negative charge) was found to be 0.70 at μ=0.025 and 0.79 at μ= 0.045. The fact thatf<1 is interpreted as due to electrostatic repulsion between the dye molecule, when ionized, and the iodide ion. Due to counter ion screening the effect is less accentuated at higher μ. The quenching constant for riboflavin (which does not contain the ionizable phosphate group) was found to have the same value, 30 M‐1both at pH 5 and at pH 8, and with n

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1966.tb05782.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

Abstract—The irradiation of TMV with u.v. light of 2537 Å wavelength results in the binding of protein subunits to the RNA. These bound subunits are stable towards warm sodium dodecyl‐sulfate; however, the binding is not covalent since the subunits are removed by 66% acetic acid, guanidine hydrochloride, or phenol. Approximately one protein subunit is bound per lethal biological ‘hit’. The virus and the nucleic acid extracted from irradiated virus show virtually identical rates of inac

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1966.tb05783.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1966.tb05784.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1966.tb05785.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY