Volume 26, Issue 3

The existence of two presumed Mo e - and Mo 7 -periodate-complexes in aqueous solutions of various acidity was checked by ultracentrifugation and pH measurements. The experiments showed that only one complex exists and that the extent of protonation is but small.

This paper reports the synthesis, analytical data, melting points, and phosphorus chemical shifts of over seventy quaternary phosphonium salts. Most of these data have not been reported.

The preparation of 3,9-Dibromo-2,4,8,10,3,9-tetraoxodiphosphospiro- (5,5) -3,9-dithio undecan is described. From this compound or from the analogous dichloro compound the bifunctional dithio acid 3,9-Dithiol-2,4,8,10,3,9-tetraoxodiphosphospiro- (5,5) -dithio undecan, its Na- and K-salt as well as the methylester are obtained. The acid and the alkali salts give coordination polymers with many metal salts.

In contrary to catalytic hydrogenation of 1-hexene and 1-decene with RhH (CO) (ΡΦ 3 ) 3 in benzene in toluene as a solvent the reaction rate r can be represented by the equation 1/r=K/k 1 ·[H 2 ] · [M] 0 · [M] 0 · [Κa] 0 +Ka]o+1/k 1 · [H 2 ] · [Ka] 0 , yet, only in a very small concentration range of substrate 1-heptene [=M]. However, if free ligand ΡΦ 3 , was added to the reaction mixture, formation of the more active catalyst RhH (CO) (ΡΦ 3 ) 2 was supressed and r could be measured only for the catalyst RhH (CO) (ΡΦ 3 ) 3 s . In this case kinetic data can be represented by the equation 1/r proportional 1/[M] 0 .

The OH-radical adds to furan, thiophene and pyrrole in diffusion controlled reaction. The rate constants of these reactions and the spectra of the products were determined. The OH-addition products of furan and thiophene dissociate in alkaline solutions. The anions undergo ring scission: In the case of pyrrole, the addition product picks up a proton and the cation undergoes scission: The pK values and rate constants have the following values: (1) pK = 9.9; k = 1,4·10 6 s -1 , (2) pK = 9,2; k = 5,3 · 10 105 s -1 , (3) pK = 4,5; k = 2,2 -10 3 -1 . The radicals formed by ring scission disappear by mutual interaction.

The application of “formal integration” to general reaction kinetics is described. Its advantages are demonstrated by using photoisomerization of azobenzene. The greater significance of this kind of analysis compared with graphical methods is pointed out. A computer program was set up for numerical calculation. For photokinetical experiments a special irradiation unit had to be constructed.

UV-Photolysis of aqueous solution of 5-iodouracil in presence of oxygen and methanol leads quantitatively to isodialuric acid, uracil, formaldehyde, H 2 O 2 and iodine. The yields of these products were determined as a function of methanol concentration. The results suggest that the primary step is the homolytic splitting of the C-I-bond. The reaction of the uracil radical with methanol gives uracil and a CH 2 OH-radical, and with oxygen isodialuric acid. The uracil radical reacts 24 times faster with oxygen than with methanol. The reaction of CH 2 OH-radical with oxygen gives formaldehyde and H 2 O 2 .

Pulse - Fourier - Transform- 13 C-NMR spectroscopy allowed the direct recording of 13 C-NMR spectra of amino acids and peptides with natural abundance of 13 C isotopes within a reasonable time. The 13 C-signals of more than 50 free and protected amino acids and several peptides were assigned. 13 C-NMR spectroscopy gives valuable information about the carbon skeleton, thus offering a new analytical tool for the study of biopolymers and their constituents.

3,4-Dichloro-1-bromo-cyclobut-1-ene and diironenneacarbonyl do not form the expected bromocyclobutadiene-irontricarbonyl. Instead, two complex molecules are connected to bis (cyclobutadienyl-irontricarbonyl) by elimination of the bromine atoms.

7,8-Dihydrofolic acid and tetrahydrofolic acid were prepared from folic acid. The three compounds were examined by different polarographic methods. The diffusion coefficient of folic acid was determined independently. Folic acid is reduced via a reversible 2-electron step, an irreversible transformation of the primary product, giving 7,8-dihydrofolic acid. The reduction is continued by two further 2-electron steps with an intermediate chemical reaction (the cleavage of the side chain). The redox potentials are measured and the mechanism of the reaction is discussed.

The mass spectra of 1-dimethylaminonaphthalene-5-sulfonyl derivatives of the phenolic aldehydes 4-hydroxybenzaldehyde, 3-hydroxybenzaldehyde, vanillin, isovanillin and protocatechualdehyde were determined and discussed.

Ribonucleic acids labeled with 14 C- or 3 H-orotic acids, respectively were extracted from aliquots of mouse liver homogenates according to the cold-phenol-method of Kirby or the method of Georgiev employing different temperature steps. This comparative analysis showed that only ca. 50% of the total labeled RNA was extracted by the Kirby method. Especially the high molecular D-RNA and R-RNA were not sufficiently extracted, as was demonstrated by hydroxyapatite- and methylalbumin-Kieselgur column chromatography. Reextraction of the tissue at 65 °C first extracted by the Kirby method resulted in a recovery of most of the missing nucleic acid species. Therefore, results obtained by the Kirby and Georgiev methods will be different in regard to the nucleic acid composition. These findings could explain contradictary results about this problem in literature.

In the myenteric plexus of rat stomach, ileum, and rectum, glial cells outnumber nerve cells by more than 3 to 1; they have several processes, extensively branching, which extend between, and adapt themselves to, other cellular elements, constituting a very compact structure. The most prominent feature of glial cell cytoplasm are bundles of gliofilaments. No basement membrane surrounds individual glial cells; a single basement membrane is observed around the whole ganglion. Morphological features do not support the identification of these cells as Schwann cells, but relate them to the central nervous system astrocytes.

Treatment of the electron transport membrane fraction of Rhodospirillum rubrum with phospholipase A from the venom of Naja Naja resulted in a stimulation of NADH- and succinate-cytochrome c-reductase of the electron transfer chain. The mechanism of this stimulation appears to be identical with that found in the presence of the anionic detergent deoxycholate. At the same time the NADH oxidase system is inactivated while NADH- and succinate dehydrogenase remain unaffected. None of the activities mentioned becomes solubilized as the result of phospholipase action; likewise no protein is released. The stimulated activities, the kinetic properties of which remain unchanged, are inactivated by proteases at significantly slower rates than those of particles not treated with phospholipase A. The phospholipases C and D were found to be without any effect on the membranes. The following additional information was obtained with phospholipase A in the system studied here: The enzyme from Naja Naja venom does not require Ca 2⊕ for activity. Phospholipase A prepared from the venom of Crotalus adamanteus is completely ineffective with the electron transfer activities of the particulate fraction.

1. Conidia of Neurospora crassa were either subjected to osmotic shock or treated with the detergent triton X-100. A decrease in the amount of 14 C-sorbose taken up, as measured by means of the millipore filter technique, served as criterium for the efficiency of both procedures. Treated cells were either a) pregerminated with fructose, b) ungerminated but preincubated with sorbose or c) ungerminated and not preincubated, to check for a possible loss of fructose-inducible, sorbose-inducible or constitutive transport components respectively. 2. In contrast to reports for bacteria, osmotic shock by transferring conidia from 30 - 60% sucrose solutions to 5·10 -4 м MgCl 2 -solution after 5 minutes did not decrease transport activity. Rather there was an increase in the amount of sorbose taken up after such treatment (Table 1). However, if sucrose was replaced by concentrated minearl salts solution (Vogels minimal 4.75 м stock solution) a drastic decrease of sorbose uptake was observed in conidia pregerminated with fructose (Fig. 1). Ungerminated conidia preincubated with sorbose did not respond to a shock with mineral salts solution; they did however respond, if 2% triton was added to the salts solution (Table 2). Triton alone was uneffective under comparable conditions (Table 2), but it became effective if the triton concentration was increased and the duration of treatment was extended to 30 minutes (Fig. 2). Ungerminated, not preincubated conidia showed the same reduction of sorbose uptake if treated with triton in this way (Fig. 2). 3. Whenever a decrease of sorbose uptake was observed, it was correlated with a decrease in cell survival. However, the amount of killing does not suffice to explain in full the decrease in sorbose uptake per sample. Thus even surviving cells demonstrate a decrease of sorbose uptake, the reasons for which are considered as follows: a) Cells preloaded with 14 C-sorbose show the same rate of sorbose efflux, whether shocked with mineral salts solution or not (Fig. 3). The shock therefore does not cause an unspecific leakiness of the cell wall or membrane. b) Oxygen consumption in cell suspensions, as measured by an oxygen macro electrode, is strongly retarded for fructose pregerminated cells which have been shocked with mineral salts solution (Fig. 4). This retardation together with killing is fully sufficient to explain the decrease in sorbose uptake observed. Ungerminated cells preincubated with sorbose do not show this effect, not even after prolonged treatment with triton, when their ability to take up sorbose is reduced. Hence, in such material a loss of specific transport components is indicated.

For optimal growth of embryonic rat cells in tissue culture the amino acid serine is essential. It can be substituted by equimolar amounts of glyoxylic acid; radioactivity from 1- 14 C-glyoxylic acid is incorporated into various amino acids among which serine is also found. The presented experiments show that there must be a deficiency of C 2 -fragments in the metabolism of embryonic rat cells.

In systems containing singlet-oxygen and aromatic fluorescers energy transfer from singletoxygen dimers to the dye should be observable by emission of the fluorescer. In order to prove this hypothesis, externally generated singlet-oxygen ( 1 Δ g ) was bubbled through the solutions of dyes (chlorophyll a, eosin y, rhodamine b, luminol, rubrene and acridine orange) in organic solvents. Luminescence could be observed and its spectral distribution analyzed by sharp cut-off filters and interference filters (rubrene) . Spectra, rates of oxidation, addition of quenchers and the long lasting time dependence of the reported reactions lead to the conclusion that the observed afterglow is due to chemical oxidation mechanisms producing a chemiluminescence. Therefore an excitation of the substances investigated in these experiments by simple physical energy transfer seems not to be predominant.

Three fractions of carotenoid esters (I, II, and III) were isolated from nitrogen-deficient cells of the green alga Ankistrodesmus braunii. I and II are composed of diesters of astaxanthin with C 16 -, C 18(2 =) -, and C 18(3 =) -acids in different combinations. Ill consists of monoesters of 3-oxi-3′,4,4′trioxo-β-arotene with C 18(2 =) -, and C 18(3 =) -acids. The pattern of fatty acids of the total lipids is quite different from that of the ester fractions I, II, and III (see table 1). Therefore it has been concluded from this selective esterification that specific enzymatic reactions occur even in old nitrogen-deficient algae.