Volume 29, Issue 7-8

The structure of 2-(m-Br-benzyl) -4,7,8,9-tetra-O-acetyl-N-acetyl-α-ᴅ-neuramine acid was solved by heavy-atom methods using three-dimensional X-ray data. Known biochemical properties of the molecule allow to determine the absolute configuration.

Polarographie reduction of adenine and cytosine moieties in denatured DNA was followed by means of differential (derivative) pulse polarography. The measurements of the reduction currents yielded by samples of denatured DNA differing in guanine+cytosine (G + C) content showed that both cytosine and adenine residues were reduced in DNA in the pH range of 6.0 -8.7. The contribution of their reduction to the total reduction current of denatured DNA differs in the range pH 6.0 -8.7, however; the contribution of the current of adenine residues to the current of DNA decreases with increasing pH as compared with the contribution of cytosine residues. It was also shown that in the region of neutral pH reduction current of denatured DNA is independent of the G + C content in DNA.

The surface properties of mixed monomolecular films of retinal and phospholipids were studied at a nitrogen/water interface. The subphase was glycine buffer pH 10.5 with an ionic strength of 0.1. Monomolecular films of retinal in the presence of amino acids were also measured. The area per molecule, at a surface pressure of 10 dyn/cm, A 10 , in the dark for 9-cis retinal and 11-cis retinal are 42 Å 2 and 47 Å 2 , respectively. After irradiation A 10 for 9-cis retinal and 11-cis retinal dcerease to 40 Å 2 and 43 Å 2 , respectively. The surface potentials, ⊿V, at a surface pressure of 10 dyn/cm, in the dark for 9-cis retinal and 11-cis retinal are 470 mV and 445 mV, respectively. After irradiation, AV for 9-cis retinal decreases to 435 mV and 11-cis retinal increases to 490 mV. Interaction was observed between retinal and phospholipids and amino acids. The A 10 and ⊿V 10 of mixed films of retinal and phospholipid were measured as a function of the mole fraction of phospholipid. Maximum interaction is observed at mole ratios of; phosphatidylserine/9-cis = 1; phosphatidylethanolamine/9-cis = 2, phosphatidylserine/11-cis = 3; phosphatidylethanolamine/11-cis = 3. It is shown that mixing and interaction between phosphatidylethanolamine and retinal is spontaneous. The A 10 and ⊿V 10 of films of retinal were measured as a function of the molar concentration of amino acid in the subphase. The nature of the interaction between retinal and phospholipid and amino acid are discussed.

Stepwise formation constants corresponding to 1:1 vanadyl complexes with methionine, phenylalanine and threonine have been determined at 25 °C, and at various ionic concentrations, viz. 0.01, 0.1 and 0.3 ᴍ , maintained by the addition of potassium chloride solution. Thermodynamic stability constants have been obtained by extrapolation of log K values to zero ionic strength. Logarithms of the overall stability constants (log K (u = 0) ) are 7.72 for methionine, 7.70 for phenyl­alanine and 7.44 for threonine complexes. The corresponding free energy changes (⊿G 0 ) are - 10.53, - 10.51, - 10.15 kcal-mol -1 respectively.

Stepwise stability constants of the interactions of 7,8-dimethyl (ribo-2,3,4,5-tetrahydroxypentyl) isoalloxazine (riboflavine) with Y (III) , La (III) and Ce (III) have been determined at 35 and 45 °C and ionic strength of 0.05 ᴍ using Bjerrum-Calvin pH titration technique. The values of free energy (⊿G), enthalpy (⊿H) and entropy changes (⊿S) have been reported.

Isocytosine and isocytosine-d 3 crystals have been investigated at 300 K, 90 K, and 10 K by infrared spectroscopy; the Raman spectra of crystals and solutions in H 2 O , D 2 O have also been studied. Using these data and the frequency group approximation we propose assignments of the fundamental molecular frequencies. Eleven lattice vibration frequencies have been observed in absorption and nine in diffusion.

The study of the anthraquinones of Asphodelus fistulosus and A. microcarpus resulted in the isolation of chrysophanol, aloe-emodin, anhydrorugulosin, three others bianthraquinones (the cleavage products of which are either 1 ,8 -dehydroxyanthraquinone or chrysophanol) and chrysophanol-8 -mono-β-ᴅ-glucoside. The obtained results revealed a qualitative difference in the anthraquinone content of the different parts (leaves, seeds and tubers).

For the first time, quercetin-3-β-ᴅ-glucuronide, quercetin-3-β-ᴅ-glucoside, quercetin-3-(O-malonyl) -β-ᴅ-glucoside and luteolin-7-/9-ᴅ-glucuronide were isolated from lettuce and kaempferol-3-β-D-glucuronide and kaempferol-3-β-ᴅ-glucoside from endives as crystals. The flavonol glucuronides are the main glycosides. Moreover a glycoside was found in endives which is very probably identical with kaempferol-3-(O-malonyl) -β-ᴅ-glucoside.

The predominant caffeic acid compound of endives has been crystallized after column chromatography on polyamide and cellulose and was identified as ᴅ -(+) -dicaffeoyl tartaric acid.

δ-Amyrenon, known previously as constituent of leaves in the genus Alnus, is shown to form an important part of the triterpenoid excretions on buds of various alder-trees.

In an investigation of Hypogymnia physodes (L.) Nyl. a new depsidone Physodol has been isolated. UV, IR and HrMS studies were used in the investigation. The structure of the component is given in Scheme 1.

Stilbericoside, a new iridoid isolated from Stilbe ericoides, is shown to have structure 1. The relative configuration is deduced mainly from NMR spectra and double resonance experiments. Because of the great similarity of their NMR spectra 1 and unedoside, a known iridoid, which also occurs in Stilbe ericoides, very probably have the same relative configuration. Unedoside therefore should be represented by formula 2 rather than by the hitherto accepted formula 3 .

Cell suspension culture of Phaseolus aureus, Glycine max and Pisum sativum have been used to determine the extent of chalcone and isoflavone catabolism. The A-rings of calcones and isoflavones with both resorcinol and phloroglucinol pattern of sub­stitution have unequivocally been shown to be degraded as measured by carbon dioxide production The earlier described catabolic pathway of chalcones with the B-ring liberated as a substituted benzoic acid has been verified using another chalcone. With the use of various 14 C-labelled isoflavones it could be demonstrated that essentially all carbon atoms are introduced into catabolic reactions. Incorporation of 4',7-dihydroxyisoflavone (daidzein) into insoluble polymeric material has been shown to proceed via the 3',4',7-trihydroxyisoflavone. 3'-Hydroxylation and subsequent polymeri­sation of the orto-dihydroxy compound can completely be inhibited by using anaerobic conditions which favour glucoside formation instead. 4'-O-Methylgroups in isoflavones prevent the phenolase catalzyed 3'-hydroxylation and thus the incorporation of isoflavones into polymeric structures. 6,7-Dihydroxy substituted insoflavones when fed to cell cultures are not polymerized by phenolase but are rather converted to glycosides.

A monospecific antiserum to ferredoxin-NADP + -reductase inhibits the diaphorase activity of soluble ferredoxin-NADP + -reductase from chloroplasts. Two states of the molecular structure of the lamellar system have been observed, one of which is the state described earlier by Berzborn. Stroma-freed chloroplasts in this condition are not agglutinated by the antiserum, although a specific adsorption of antibodies to reductase onto the lamellar system was demonstrated by the Coombs test. However, a second type of chloroplast preparations gives direct agglutination upon addition of the antiserum. Apparently, agglutination in this state is not sterically hindered by neighboring protein structures. This type of chloroplast preparations appears swollen under the light micro­ scope, but exhibits high rates of electron transport. Chloroplasts of three types of tobacco have been used which differ in the morphology of their lamellar systems. The green type contains a normal ratio of grana and intergrana regions whereas the other two types have extended intergrana regions with either only small grana or no partitions at all. Comparison of the maximal degree of inhibition of the NADP + -reduction in chloroplasts from these types of tobacco by the antiserum, leads to the conclusion that ferredoxin-NADP + -reductase is located in the grana and the intergrana regions of the lamellar system, in the outer surface of the thylakoid membrane.

Long-term and short-term effects of phytochrome on the levels ("tissue contents") of NAD, NADH 2 , NADP and NADPH 2 were measured in the cotyledons of the mustard (Sinapis alba L.) seedling. It was found that long-term far-red light (which is considered to operate exclusively via active phytochrome, P fr ) strongly increases the levels of NADP and NADPH 2 , whereas this light treatment suppresses the levels of NAD and NADH 2 below the levels present in the cotyledons of the dark grown seedling. The high levels of NADP and NADPH 2 as well as the low levels of NADP 2 (and probably also NAD) are actively being maintaned by the far-red light. In experiments with light pulses it was found that a red light pulse causes a rapid but transient rise in the level of NADPH 2 under all circumstances (dark-grown seedlings and seedlings pretreated with long-term far-red lig h t). The operational criteria for the involvement of phytochrome (P fr ) are fulfilled. In the case of NADP a significant rise of the level following a red light pulse could only be observed if the seedlings were pretreated with long-term far-red light. Dark-grown seedlings do not significantly respond. In the case of NAD and NADP 2 no significant changes could be induced by light pulses either in dark-grown seedlings or in seedlings pretreated with long-term far-red light. It is concluded that NADPH 2 does neither originate from NADP 2 nor from NADP. It is further concluded that it is unlikely that nicotinamide nucleotides are links in any causal chain originating from P fr and leading to phenomena of photomorphogenesis. We favour the con­cept that the phytochrome-mediated changes caused by light pulses occur in the plastids.

The colourless algae, Prototheca portoricensis, Polytoma oviforme, Chlorella variegata (Chlorophyta), and Chilomonas paramecium (Pyrrhophyta) mainly synthesize the 16 : 0, 18 : 1, and partly also 1 8 : 2 and 18 : 3 fatty acids. The major lipids formed were neutral lipids (glycerides and sterol esters) and phospholipids. In their fatty acid content, these organisms resembled fresh water green algae. They differed from the photosynthesizing fresh water green algae, however, in containing none or very low amounts of polyunsaturated C 16 acids (16 : 2 , 16 : 3) and glycolipids.

Incubation of thymidine diphospho(TDP)-ᴅ-[U- 14 C] -glucose with a cell-free extract from Streptomyces aureofaciens and subsequent hydrolysis of the nucleotide sugars led to the formation of 4 radioactive products (I -IV ). Addition of pyruvate to the incubation caused an increase in the amount of I I I and a decrease in that of II. Product I was identified as 4-keto-6-deoxyglucose. Product III was isolated on a preparative scale as the methylglycoside and was identified as α-methyl- 2,6-dideoxy-4-C-[1'-oxoethyl]-ʟ-lyxo-hexopyranoside (Fig. 1, 3) from its NM R spectrum and by its borate complex formation, which established the cis configuration of the hydroxyl groups at C-3 and C-4. The oxoethyl-branched sugar formed in the cell-free system is epimer at C-3 with the sugar formed in vivo by S. aureofaciens. The reason for this difference is not clear. Product II could be tentatively formulated as 4-keto-2,6-dideoxy-ʟ-lyxo-hexopyranose (6 ) on the basis of its chromatographic and chemical properties and its reduction by sodiumborohydride to two sugars. The products II - IV were also obtained when TDP-4-keto-6-deoxyglucose was the substrate of the reaction. Addition of thiaminepyrophosphate to the incubation in the presence of pyruvate did not increase the yield of III . The increasf in the amount of III formed in the presence of pyruvate could be inhibited by addition of glyoxylic acid. After incubation of [α- 14 C]-hydroxethyl-thiaminepyrophosphate with TDP-glucose in the cell-free extract no radioactive III could be detected.

The elements Cu, Ag, Au, Cr, Fe, Zn, As, Mo and W have been determined in human skin using the neutron activation technique. The values are compared to values published in the literature. The values are scattering over a wide range, leading to the assumption of an uneven distribution of the trace elements in human skin. From the results of a special sample it is concluded that carrying a golden ring over a longer period of time will not contaminate the skin by gold or copper. The investigation of a skin sample where gold has been plated out showed a maximum of the gold concentration beneath the skin surface.

A Cameca IMS 300 ion analyzer has been used to measure fluorine concentrations in tooth material. Samples of human and shark teeth were studied. Negative oxygen primary ions produce secondary mass spectra in which positive as well as negative fluorine ion peaks are well re­ presented. With constant measuring conditions, the reproducibility of the F/Ca ion ratios is satisfactory. Fluorine concentrations in the 10 ppm region are easily recorded. By means of samples previously measured by macroscopic F-determining methods, a calibration can be effected to obtain, from the ion current ratios, at least semiquantitative values of F-concentrations. In a sample of human enamel, the F-concentration was found to vary from about 3000 ppm at the surface to about 100 ppm in the interior. In shark enamel the composition at the surface cor­ responded to nearly saturated fluorapatite, 3.6% F, but the fluorine concentration decreased distinctly at increasing depth.

A diurnal rhythm of cell proliferation exists in the liver of young rodents and in the growing liver of rats treated with α-hexachlorocyclohexane (α-HCH). The timing of the rhythm is dependent on the time of feeding but independent from the lighting regimen. This suggests that under natural circumstances the light-dark rhythm synchronizes the rhythm of hepatocyte proliferation by con­ trolling the animals' feeding habits.

After explaining the significance of a cytolysis chain reaction within the set of problems encountered in cancer therapy, all our previous studies on the lysosomal chain reaction and its problems are summarized. It follows a report on a new fundamental in vitro test showing that, at pH = 5.8, T = 42 °C and in cell suspensions with high cell volume portion ( Ɛ Z = 4 0 · 10 -3 ), EMAC cells are damaged very much quicker than in suspensions of only low cell volume ( Ɛ Z = 2·10 -3 ). Furthermore, there is an increase in acidic phosphatase in the suspension milieu of high cell densities. In addition, it can be pointed out that the observed damaging of cells is closely linked with the complete inhibition of glucose metabolism. The described findings are to be taken as a strong circumstantial evidence for the efficiency of cell damaging chain reactions.

Statistical calculations on sequence homologies provide evidence that the two phages Qβ and R17 have derived from a common precursor, although they are quite different in several properties. Moreover, duplications within the genom of each phage have occurred. These results are discussed with regard to the lack of translational repression between Qβ and MS2 phage group.

Chick helper factor (chf) negative chick embryo cells were exposed in the presence of DEAE-dextran to chromosomal DNA isolated from avian leukemic myeloblasts which had been induced by infection with the BAI-A strain of avian myeloblastosis virus (AMV) (subgroup B) . After several transfers, avian C-type virus production was observed in the cultures with electron micro­ scopy, although no alteration in the cell morphology was apparent. Virus interference tests revealed that this virus was infectious and belonged to subgroup B of the avian RNA toumor virus (ATV) group. The virus induced nephroblastomas 2 months after intraperitoneal inoculation of chickens; no myeloblastosis was observed, however, and the virus could neither transform chick embryo cells in vitro nor induce wing web tumors in vivo. The nephroblastomas also produced virus which was again shown to be a member of subgroup B. From these results it was concluded that the virus transmitted in these experiments was avian myeloblastosis associated virus (MAV), an avian leukosis virus known to be present as a major component in AMV stocks.

In the course of investigation on chemical constituents of essential oil of the liverwort, Bazzania pompeana, the lowboiling constituents were identified as β-pinene, γ-terpinene, 3-octanone, camphor and thujanol.

The final structure of the Cascarosides A, B, C, D from Rhamnus purshianus D. C. was clearified by chemical and optical methods.

1.2.4-Trihydroxybenzene is a characteristic chromogen of Gomphidius (Boletales), responsible for the colour changes to red and dark brown when the sporophores are hurt.

Saccharomyces cells were grown in a 58 000 A/cm magnetic field and then exposed to UV-irradiation. An increase of the survival rate is observed. The application of magnetic field just after UV-exposure shows a decreased survival.

Intracellular recordings from the dragonfly lamina show that the light initiated hyperpolarising response of large monopolar cells (LMC's) is associated with a resistance decrease. The response reversal potential is at least 40 mV negative to the dark resting potential. The adaptation of the response to a maintained stimulus is associated with a decrease in hyperpolarising input.

In the flight-muscle of Locusta migratoria the adenyl cyclase shows the specific activity of 27.4 ± 8.3 pmol cAMP/ mg protein · min. Among the fraction obtained by differential centrifugation approximately 85% of the activity recovered is located in the myofibrillar fraction, and 11% in the mitochondrial fraction.

Several questions are raised concerning the Popp model of carcinogenesis by polycyclic hydrocarbons.

Resonance Hypothesis, Carcinogenesis, Polycyclic Hydrocarbons Three criteria for carcinogenic polycyclic hydrocarbons, which are to be satisfied, are discussed in regard to a resonance-hypothesis of carcinogenesis. According to this hypo­ thesis, the carcinogenic effect is caused by a Fermi-resonance between α-states and p-states which possibly leads to the breakage of pairing theorem by an asymmetric potential, in certain cases caused by vibronic coupling.