Volume 26, Issue 2

SF 4 reacted with N-organyliminohosphoranes by splitting the P = N-bond. Sulfurdifluoridimids and triphenyldifluorphosphoran were formed.

By reaction of N-sulfuroxideimides with phosphorus-pentabromide the compounds R-SO 2 NPBr 3 (R = CH 3 , CF 3 , C 6 H 5 , p-Cl-C 6 H 4 , and p-CH 3 C 6 H 4 ) were prepared. Reactions of hexamethyldisilazane and N- (dimethyl) -trimethylsilylamide resulted in the formation of R-SO 2 NPBr 2 N (CH 3 ) 2 , (R = CH 3 , C 6 H 5 ), and R-SO 2 NPBr 2 NHSi(CH 3 ) 3 (R = CF 3 , p-CH 3 -C 6 H 4 ). The properties and the chemical behavior of these compounds are described. Results of IR-spectra, as well as 31 P-, 19 F-, and 1 H-NMR-spectra and elemental analysis characterize the compounds.

Cobalt (II) and Nickel (II) complexes of o-nitrophenole and methylsalicylate were prepared. The coordinated ligand atoms were determined by IR-spectroscopy. Spin densities indicating reac tive ligand sites to which radicals can be attached were determined by NMR-spectroscopy.

Sodium sulfonyl and phosphoryl amides together with dimethylchlorophosphine yielded PH-phosphine imines 4 instead of NH-aminophosphines 3. Sodium trifluoromethylsulfonyl amide did so even with diphenylchlorophosphine. In a second step biphosphine monoimines were formed in all cases. The dependency of δ 31 P, J PH and J PP is discussed.

Dipole moments of the ten isomeric phenanthrolines are presented and discussed shortly. They could be computed in a close approximation from the dipole moment vectors of the individual pyridine nuclei. Dipole moments calculated by means of the CNDO/2-method are in agreement with the experimental data.

Binary mixtures of homologous nematic N- (p-alkyloxybenzylidene) -p′-acyloxyanilines always show the same eutectic composition of 2 moles of lower melting and 1 mole of higher melting component. The melting point of such eutectics is more depressed with respect to the melting point of the individual components than their clearing point. This results in a marked broadening of the nematic range towards lower temperatures. It is therefore possible to obtain nematic liquid crystaline systems with melting points below 0 °C and mesophases of up to 120 °C.

The aminomethyl-group of porphobilinogen reacted as an alkylating agent in alkaline solution with primary and secondary amines, amino alcohols, certain amino acids, and C-H acidic compounds. The uroporphyrinogen formation competed with these reactions. An elimination-addition mechanism is discussed. The possibility of this reaction acting a part in the biosynthesis of corrin ring formation is indicated.

The formation of a 2-oxo-azetidine from N-phenyl-N-chloroacetyl-4-fluoro-phenacylamine, and 3-oxo-morpholines from corresponding 4-bromo-derivatives 2 indicates the possibility of the existence of d π -acceptor resonance between the aromatic ring and the bromo-substituent. H-NMR studies of some morpholines reported earlier 3 indicate a planar heterocyclic structure with a rapidly inverting N₋aryl substituent. Where the rotation of the N-aryl group is strongly hindered 16 , the C 2 methylene protons show a geminai coupling of -14.5 Hz 4 . The 2-oxo-azetidine (4) shows an ABX coupling pattern for its ring protons. Preliminary work attempting to extend the synthesis of morpholines to azepines has resulted instead in the formation of a pyrrolidone.

The pK s * of the equilibrium between the monoacid dyecation and the methylester of twelve organometalically synthesised triphenylmethane dyes were measured spectrophotometrically in methanolic buffer solutions. The pK s of the water-soluble dyes were used to derive an equation, which allows calculation of the pK s (aqueous) of the water-insoluble dyes. The experimental equilibrium constants, which can be interpreted by HMO calculations, satisfy the Hammett ρ-σ-equation.

The coenzyme analogue nicotinamide 5-iodouracil-dinucleotide was synthesized by condensation of the two mononucleotides with dicyclohexylcarbodiimide in aqueous pyridine. The enzymatic properties of this compound were compared with those of the nicotinamide-uracil-dinucleotide. Both coenzyme analogues reacted slowly when functioning as a hydrogen carrier in enzymatic tests. The properties were similar to those of nicotinamide-benzimidazole-dinucleotide. The difference spectrum between the intact coenzyme analogue and its mononucleotides showed that the intramolecular interaction between the functional and non-functional moiety was smaller than that in NAD. The interaction corresponded to that of nicotinamide-benzimidazole-dinucleotide. The fluorescence excitation spectrum did not show any energy transfer from the non-functional iodouracil to the dihydronicotinamide part of the analogue. Difference spectra between the coenzyme - enzymecomplex and the two isolated components indicated that the unfolded dihydrocoenzyme was bound to the active site of lactate- and alcohol-dehydrogenase, respectively. Furthermore, they showed aromatic interaction of the non-functional part with parts of the protein. Introduction of iodine into the nicotinamide-uracil-dinucleotide did not remarkably alter the behavior of the analogues. As the iodine is bound very strongly to the coenzyme analogue, it may be useful for X-Ray-investigations of the dehydrogenases.

Three new natural coumarin substances 1, 2 and 3 (derivatives of 2′,2′-dimethyl-3′,4′-dihydroxydihydropyrano-5′,6′:6,7-coumarin) were isolated from the roots and fruits of Peucedanum arenarium W.K. On the basis of the spectral data from UV, IR, and NMR spectra of coumarin 1, named peuarenarine, it was assumed, that, it is an ester of 2′,2′-dimethyl-3′,4′-dihydroxy-dihydropyrano-5′,6′:6,7-coumarin and of angelic and 2,3-epoxy-2-methylbutyric acids.

Hydration dependent changes of DNA conformation of calf thymus DNA, Locusta sperm DNA, calf thymus and Locusta sperm nucleohistone and Locusta DNA in situ were studied by means of linear dichroic measurements. A comparison of the results leads to the following conclusion. The changes of DNA conformation in situ as a function of the degree of hydration may depend on the species specifity of (a) both DNA and protein of the complex, (b) the conformation of the complex and (c) the interactions between DNA and protein.

Monomolecular films of cis or trans isomers of retinal were spread at a water-air interface. Isotherms were measured. The area per molecule (extrapolated to zero pressure) for 9-cis retinal, all-trans retinal, and 13-cis retinal on 10 -2 ᴍ phosphate buffer at pH 6 is 56 Å 2 , 54 Å 2 and 45 Å 2 , respectively. Complexation was observed between 9-cis retinal (9-cis) and β-mercaptoethylamine (MEA) dissolved in the subphase; however, ʟ-lysine does not appear to form a complex wth 9-cis retinal. The area per molecule of the complex as a function of subphase concentration (MEA) was determined. The area per molecule for 9-cis is decreased to 49 Å 2 after irradiation with blue light. Irradiation does not appear to break the complex between 9-cis and MEA. The lower limit for the quantum yield for photoisomerization of 9-cis, on phosphate buffer, is 0.06. When 9-cis is complexed with MEA (5 × 10 -6 ᴍ) the quantum yield for photoisomerization is lowered, e. g. at 5 × 10 -6 ᴍ MEA the yield is 0.03.

The sensitivity of the photographic emulsion is an important factor in the resolution of autoradiographs at the electron microscopic level. In a number of recent publications, single hit processes have been considered sufficient for the production of developable latent images by tritium electrons. However, since the absorbed energy required for latent image formation in AgBr crystals of commercially available emulsions is of the order of 800 eV, only low energy tritium electrons (up to 3 keV) will produce latent images by single hit processes in small AgBr crystals of about 400 Å diameter. In emulsions with larger AgBr crystals (about 1000 Å diameter), electrons with an energy of up to about 6 keV can be registered by single hit processes. Evidently, latent image formation may also result from multiple hits by electrons of higher energy. Since the energy absorption required for latent image formation is constant, the sensitivity of photographic emulsions must be considered proportional to the diameter of the respective AgBr crystals, unless methods become available for specific sensitization of emulsions with small AgBr crystals.

The sparing effect of UV- and X-ray dose fractionation and the influence of pre-exposure starvation were investigated in diploid yeast, Saccharomyces cerevisiae. A sparing effect could be demonstrated in starved cells if they were incubated in fresh nutrient medium during the fractionation interval. The time necessary for complete recovery, however, was greatly increased as compared to unstarved stationary phase cells. The possible role of cell progression and partial synchronization is discussed.

Photoreactions and complexation reactions between monolayers of chloroplyll a, at a water-air interface, and various electron donors and acceptor in a Wilhelmy film balance. When phenazine methosulfate (PMS), ascorbate, benzyl viologen (BV), or dehydroascorbic acid are present in the aqueous subphase, the area/molecule increases with substrate concentration in accordance with a Langmuir- type adsorption isotherm. The increase in area is attributed to a reorientation of chlorophyll upon complex formation. The surface potentials and areas/molecule (at zero pressure) are 350 mV and 179 Å 2 for PMS + ascorbate in the subphase, 300 mV and 175 Å 2 for PMS, 310 mV and 146 Å 2 for BV, 310 mV and 156 Å 2 for ascorbate, 230 mV and 146 Å 2 for dehydroascorbic acid. The equilibrium constants are 170 × 10 3 ᴍ -1 for PMS + ascorbate, 64 × 10 3 ᴍ -1 for PMS, 41 × 10 3 ᴍ -1 for BV, and 3.9 × 10 3 ᴍ -1 for ascorbate. Formation of a complex decreases the slope of the isotherm, thereby giving the film a more liquid nature. Chlorophyll does not complex with oxidized PMS. Illumination of the chlorophyll · BV complex in a nitrogen atmosphere results in an oxidation of chlorophyll; the photoproduct (probably Chl ⊕ · BV ⊖ ) has a larger area/molecule, of 165 Å 2 , and a lower surface potential, of 280 mV. Illumination of the chlorophyll · ascorbate complex or the chlorophyll · PMS · ascorbate complex results in a reduction of chlorophyll. The photoproduct of the former reaction (probably Chl ⊖ · -oxidized ascorbate) has a larger area/molecule, of 169 Å 2 , and a lower surface potential, of 290 mV. The photoproduct of the latter reaction (probably Chl ⊖ · PMS · oxidized ascorbate) has a larger area/molecule, of 211 Å 2 , and a larger surface potential, of 380 mV. No evidence is observed for a photoreaction with the Chl · PMS complex or the Chl · dehydroascorbic acid complex. A value of 0.03 is determined as a lower limit for the quantum yield of these reactions. In all cases the absorption spectrum of the chlorophyll recovered from surface after irradiation shows no significant differences from the control.

Ingestigations on the thymidine kinase activities within a cell-cycle of synchronously growing Chlorella cells showed a marked increase of the enzyme-activity towards the end of the DNA-reduplication. Immediately after γ-irradiation with doses of 15 krad and 35 krad, no significant changes in activity could be found; three hours after irradiation a remarkable decrease of the enzyme-activity was observed.

Hemoproteinoids related to contemporary porphyrin-dependent peroxidases were synthesized under simple conditions. The peroxidative activity of hematin increased by a factor of 50 if the hematin was bound to proteinoids whereas the catalatic activity of hematin decreased rather under the same conditions. The peroxidative activity of hemoproteinoids particularly increased with their lysine content whereas the catalatic activity especially decreased in proteinoids with high phenylalanine content. The isoelectric points of the lysine-rich peroxidic hemoproteinoids were about 8. Their relatively broad pH-activity optimum was about pH 7.0. The molecular weights were a little below 20 000. Hematin content and amino acid composition of the synthetic materials were varied greatly. The substrate specificity appeared as broad as that of biogenous peroxidases, e. g., horseradish peroxidase. Among the many substrates was NADH. The possible importance of the peroxidative oxidation of NADH-type coenzymes by primitive heterotrophic organisms or prebiological systems in an anaerobic environment is discussed.

It is shown by the use of the repetitive double flash group polarography that CCCP acts as a deactivator of the active states in the water splitting system. The other electron transport reactions in system II are not influenced by CCCP. Therefore CCCP can be used both to label and to modify the properties of the water splitting system of photosynthesis.

The two synthetic farnesol derivatives, farnesyl methyl ether and the dihydrochloride of ethylfarnesoate were found to be morphogenetically effective in a distinguishable manner in the last larval instar of Cerura vinula L. by topical application assays. The juvenile hormone-like activity of the two substances correlates with the amount of applied substances and a critical time interval to the prepupal processes. In spite of the deficiency of some prepupal processes, it is possible, that the pupal moult occurs after a long period of delay. The time lapse of the pupal development is suggested to be dependent upon some balance of the hormones of the prothoracic glands, ecdysone, and the juvenile hormone of the corpora allata.

Cl ⊖ and K ⊕ uptake by cells of variegated leaves of Oenothera and Tradescantia having normal and mutated chloroplasts, respectively, have been investigated. Under our conditions light has no effect on ion uptake. Cl ⊖ uptake is highly sensitive to FCCP in both green and mutated cells, while K ⊕ uptake is inhibited only in the green cells. Rates of ion uptake are higher in the green than in the mutated cells. The results allow two alternative explanations: (I) mutation may affect carrier-proteins and hence alter ion accumulation capacity of the cells; (II) light-independent metabolically controlled ion accumulation may be correlated with chloroplast differentiation.