Volume 34, Issue 7-8

The lichen Anaptychia fusca and several Stereocaulon species have been chemically investigated with regard to their content of unknown ninhydrin-positive com pounds. New aliphatic and alicyclic, amino components isolated from water extracts of these lichen species have been characterised as aminopentitol, am inohexitol and aminocyclitetrol. To our knowledge, this is the first time that com pounds such as these have been found in lichen material. Aminopentitol and amino­ cyclitetrol appear to be characteristic constituents of Anaptychia fusca, whereas aminohexitol has been found in several species of Stereocaulaceae.

The cuticular lipids of 4 species (Aeschna grandis, A. mixta, Sympetrum sanguineum, S. danae) of the insect order Odonata (dragonflies) have been analysed. Alkanes, triglycerides, and free fatty acids predominate and minor amounts of monoester waxes have been detected. Among the hy­drocarbons unbranched odd-numbered (56 - 66%) predominate, followed by monometnyl-alkanes with the branch in the middle of molecule (11 - 19%), 3-methylalkanes (7 - 15%), and 2-me­thyl-alkanes (1 - 13%). Moreover, alkanes (1 - 12%) were detected. The composition of triglyceri­des and free fatty acids were very similar with 14 : 0, 16 : 0, 18 : 0, 16 : 1. 18 : 1 and 18 : 2 being main constituents. Ester waxes were composed of unbranched and predominantly even-numbered fatty acids and alcohols with chain lengths C 14 - C 30 . The results are discussed from a chemotaxonomic viewpoint. Similarities of the integumental lipjids from Odonata and Plecoptera were found.

Nucleosides and nucleotides have been investigated by means of the spin-lattice-relaxationtim T 1 , the measurements carried out in CDCl 3 on the nucleosides adenosine (A), uridine (U) and inosine (I) indicate that the strength of H-bonding is highest in the basepair (A)-(U). The systems (A)-(A), (U)-(U) , (I)-(A) ana (I)-(U) however, show only a low tendency to associate. Plotting the spin-lattice-relaxationtime, of the nucleotide protons in fragments (mol weight below 40,000) originated from DNA or RNA, against increasing temperature gives a curve with a sigmoide shape and a Tm value of 80 °C. The average of the activation energy for the H-bonding is 18.02 KJ/mol. The investigations clearly show that the spin-lattice-relaxationtime measurements open first of all a new method for research on H-bonding, secondly it is even in the case of nucleosides and oligonucleotides, where most of the common methods fail, a way to get information about H-bonding effects.

Reductions with [ 3 H]NaBH 4 proof that the decrease in viscosity of hyaluronic acid solutions caused by lowering the pH does not depend on a depolymerisation of hyaluronic acid. At the same time investigations at different pH-values, show a sigmoide increase of the Spin-Lattice-Re­laxationtime T 1 . This increase depends on a progressive aggregation of the hyaluronic acid mole­cule. The effect seems to be induced by the decrease of ionization of the carboxylgroups, by acidi­fication of the solution.

In current theories of polyacrylamide gel electrophoresis, the idea prevails that molecular siev­ing relies on different accessibility of volume fractions and of cross-sectional area fractions (denot­ed “pores”) to different-sized ions due to the effect of “geometric exclusion”. This correlates with the assumption that all elements of a polyacrylamide network occupy fixed and unchangeable po­sitions thus forcing colliding macro-ions to diffuse laterally in order to find an “accessible pore” and to resume motion in direction of the electrical field. However, the alternative conception would be equally well justified, i. e. the assumption that polyacrylamide chains represent smooth obstacles cleared aside under the electrokinetic pressure of a macro-ion. This explanation would even be preferable with respect to the molecular sieving effects occuring in solutions of “liquid polyacrylamide”. Yet no theory exists as to describe such effects in quantitative terms. In the present article, a parameter is defined and discussed, which can be estimated by experi­ment, and which seems to be apt to characterize local resistivity of polymer structures against dis­location and deformation: the “fractional specific resistance”. Definition of this parameter is bas­ed on the model of a “viscosity-emulsion” composed of two interpenetrating liquid compartments which are characterized by different levels of hydrodynamic friction and the spatial dimensions of which are inferred from Ogston’s theory. This concept of “localized viscosity” may also serve as a link between theories of molecular sieving and of “macroscopic viscosity” of flexible polymers. The data of Morris, formerly taken as verifications of the “rigid-pore” concept, are now interpret­ed in terms of four factors responsible for sizediscrimination: collision frequency, duration of sin­gle contacts, size-dependent frictional force, and the extent of cooperation among fibres, due to crosslinking and to simultanous contacts of several fibres to a single macro-ion. Some functions rel­evant for problems of molecular weight determination by gel electrophoresis are discussed in rela­tion to the suggested model.

The plastoauinone antagonist 2,5-dibromothymoquinone was found to inhibit NO 3 - reduction from NADH by the nitrate reductase complex from wheat. It accepts electrons from NADH through the NADH dehydrogenase activity of the nitrate reductase. However, it does not inhibit the reduction of 2,6-dichlorophenol-indophenol by the enzyme. This suggests that the two com­pounds may be accepting electrons at different places from the enzyme. Further it was observed that reduced DCIP could be oxidized by DBMIB in the absence of NADH indicating that the electron flow in the nitrate reductase complex may take place in a unidirectional way.

3,17 β-Hydroxysteroid dehydrogenase has been enriched and purified from cytosol of Streptomyces hydrogenans. After ammonium sulfate precipitation and filtration on Sephadex G-100 the enzyme was finally purified by preparative gel electrophoresis and DEAE-Sephadex A-50 chro­matography. Polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate gave a single band of mobility corresponding to molecular weight of 70 200 ± 2 500. 3 β-. 17 β- as well as 20 β-hydroxy steroids were dehydrogenated by the enzyme in the presence of NAD + . The dehydrogenation proceeded faster than the reduction of the corresponding ketosteroids in the presence of NADH. The enzyme does not accent NADP + or NADPH as co-substrates. The apparent K m values were calculated to be 11 μᴍ for 5 α-dihydrotestosterone, 20 μᴍ for testosterone ana 68 μᴍ for epiandrosterone in the NAD + -driven reaction, 1.8 x 10 -4 m for NADH + and 1.9 x 10 -4 ᴍ for NADH. The catalytic activity was influenced by the ratio of NAD + /ATP. The inhibition by ATP appears to be of a competitive type with respect to NAD + (K i 1.15 x 10 -3 ᴍ). After sucrose gradient centrifugation in a preparative ultracentrifuge the enzyme sediments with 4.1 ± 0.1 S as estimated in comparison to other proteins of known sedimentation coefficient. The isoelectric point was determined to be 3.9 with the LKB preparative isoelectric focusing col­umn (pH 2-11) and 4.1 with the analytical flat bed polyacrylamide isofocusing (pH 3 - 5). The number of SH groups was determined to be 2 mol/mol enzyme. In the presence of 6 M urea the fig­ure inceases to 3 mol SH/mol enzyme. In the presence of an excess of p-chloromercuribenzoate the enzyme activity decreases only partially.

Several cell lines resistant to 5-methyltryptophan were selected from wild type cells of different Catharanthus roseus suspension cultures. The resistant cells had up to 30 times tne normal levels of free tryptophan. Despite the increased pool size of tryptophan anthranilate synthetase activity of resistant cells was as sensitive to inhibition by ʟ-tryptophan as wild type cells. The overproduction of tryptophan did not lead to intensified accumulation of tryptamine nor of indole alkaloids. This was supported by a low conversion of tryptophan to tryptamine in vivo and in vitro. The overpro­duction of one of the primary precursors was evidently not sufficient to stimulate the rate of indole alkaloid synthesis in Catharanthus cells.

The interaction between lyophilized samples of ascorbic acid and Cu 2+ , Fe 3+ or Mn 2+ has been investigated by means of ESR spectroscopy. All of the three transition metal ions form complexes with vitamin C, but only in the case of Cu 2+ and Fe 3+ the interaction results in a reduction of the metal ions. Cu 2+ and ascorbic acid seem to form 2 : 1 complexes with an equilibrium constant of about K = 1 x 10 7 mol -1 . None of these metal ion complexes exhibits, however, the ESR spectrum obtained with leukemic blood.

The interaction between lyophilized samples of ascorbic acid and some copper proteins (ceruloplasmin, cytochrome-c-oxidase, ascorbate-oxidase) has been investigated by means of ESR spec­troscopy. The spectra obtained are identical to the one obtained with leukemic blood. The consequences of this for the molecular events occuring in cancer are discussed. The model proposed can explain the experimental findings reported thus far (such as change in spin concentration with the development of cancer, the presence of a high concentration of antioxidants etc.) as well as reconsile the two existing and seemingly contradictory hypothesis. Possible implications for lipid peroxidation and for the respiratory process are discussed.

In the presence of very low concentrations (about 2 x 10 -7 ᴍ) of cytochalasin B (CB) the time course of actin polymerization is much more sigmoidal when followed by viscosity measurements than when followed by light scattering measurements. This suggests that under these conditions actin polymers do not immediately reach their final length but only via short ”bent“ polymers which can be detected only by light scattering but not by viscosity measurements. At higher CB concentrations (about equimolar to those of actin) CB reduces the average degree of polymerization and favors the nucleation step necessary for polymerization.

A specific class of DNA sequences, the inverted repetitive sequences, forms a double-stranded structure within a single linear polynucleotide chain in denatured DNA. The reassociation process is unimolecular and occurs very fast. Quantitative analyses have shown that these sequences com-E rise about 4-5% of the nuclear DNA of various mammalian cells (P815 mouse mastocytoma, Hela, L cells, Raji and Chang cells, and human embryonic hepatocytes) and are interspersed within sequences of other degrees of repetitiveness. After labeling the cells with L-[Metnyl- 3 H]methionine and [ 14 C]deoxycytidine, relative rates of enzymic DNA methylation were computed on the basis of 3 H and 14 C radioactivities found in py­ rimidine residues of the nuclear DNA. The results indicate that DNA of inverted repetitive sequences is methylated to a level about 50% higher than the ordinary repetitive sequences and to about 300% higher than the unique and intermediary sequences. The biological function of the inverted repeats as well as the role of their enzymic hypermethyl­ ation is unknown.

γ-irradiation inactivation of isolated ribosomes of Micrococcus radiodurans was studied by ex amining poly U directed synthesis of polyphenylalanine. Ribosomes of M . radiodurans did not show significant y-radiation sensitivity up to a dose of approx. 11.6k Gy. Cells of M . radiodurans take up more magnesium than E. coli cells unter the same conditions. The magnesium content of ribosomes of M . radiodurans was 18% higher than that of E. coli ribosomes. A possible relation between Mg 2+ -content and γ-resistance is discussed.

Protoplasts prepared from the wild type tobacco N. tabacum var. John William’s Broadleaf exhibit photosynthetic oxygen-evolution if the suspension medium is supplemented with bicarbonate. In the absence of bicarbonate no steady state oxygen-evolution is observed with such preparations. Instead, an appreciable uptake which is mainly insensitive to DCMU and which persists over hours, and therefore is no induction phenomenon, is seen. Protoplasts of the tobacco aurea mutant Su/su, which is a plant with an exceptionally high photorespiration, show an oxygen consumption in the light which is 4 to 5 times higher per protoplast than in the wild type. Again, the uptake is practically insensitive to DCMU which means that the effect is to be associated with photosystem I. This is further substantiated by the fact that protoplasts prepared from yellow leaf 1 sec­tions of the variegated tobacco mutant NC 95 also show the light induced uptake. As reported earlier, the yellow leaf sections of this mutant exhibit only photosystem I reactions. The action spectrum for this oxygen-uptake yields the spectrum of chlorophyll. Consequently, this uptake is an inherent property of the chloroplast and has nothing to do with earlier described, light-dependent oxygen consumptions, which were mainly driven by blue light and hence used some yellow pigment as the photoreceptor. No effect or contribution of yellow pigments such as carotenoids is seen since the action spectrum with the yellow tobacco mutants which have an up to 4 fold higher carotenoid/chlorophyll ratio than the wild type is identical to that of the wild type.

In intact cells of the non-gummy Azotobacter vinelandii OP CO-insensitivity of the respiratory activity increased with decreasing dissolved oxygen tension in the bacterial suspension. Upon changing from low to high aeration conditions the CO-sensitive respiration was restored. Measurement of the oxidative activity of small particles of A. vinelandii OP with NADH , ascorbate-DCPIP and ascorbate-TMPD as substrate in the presence and absence of CO indicated that the CO-insensitive site is probably identical with cytochrome a 1 , which preferably is reduced by elec­ trons from ascorbate-DCPIP. Small particles of the gum producing A. vinelandii NCIB 8660 appeared to be more sensitive towards CO with ascorbate DCPIP than the non-gummy A. vinelandii OP. In small particles the CO-insensitive DCPIP oxidase was present irrespective of the dissolved oxygen tension during cell growth. In intact cells, however, CO-insensitivity was only expressed at low dissolved oxygen tension when electrons are directed to cytochrome a 1 /o in the branched re­ spiratory chain. Intact cells of Xanthobacter autotrophicus GZ 29 exhibited a similar CO-insensitive respiration as A. vinelandii OP.

The spectroscopic (visible) properties of pigment-bearing lipid and protein particles extract­ ed from milk show that: 1) chlorophylls a and b bound to separate particles can form aggregates provided their relative concentration is high enough. Neither pheophytin a nor β-carotene, in the same conditions, form observable aggregates. 2) Chlorophylls a and b can co-aggregate when they are bound to the same particles. Pheophytin a as well as β-carotene seem to prevent the aggregation of chlorophyll a. β-carotene has no effect on the aggregation of chlorophyll b.

Male Locusta hemolymph contains JH-esterase(s) and a JH-carrier protein with high affinity and low capacity that both interact enantioselectively with juvenile hormones. Exposure of race-mic JH-I and JH-III results in preferential hydrolysis of the naturally configurated enantiomer of JH-I but the unnaturally configurated enantiomer of JH-III. The JH-carrier protein has a remark­ able specificity for the natural enantiomer of JH-III but discriminates only weakly between enantiomers of JH-I. This observation indicates a protective function of the JH-specific carrier protein for JH-III but not for JH-I. A third major protein, the diglyceride carrier lipoprotein (DGCL), shows no stereoselectivity at all.

Some synthetic analogues of insect juvenile hormone cause tremendous rise of respiratory me­tabolism in the last larval instar of Dermestes maculatus. The O 2 consumption values occasionally found in these hypermetabolic larvae (20 ml/g/h) can be classified among the most intensive res­piratory rates ever recorded in living organisms. The phenomenon is directly related to the dose of juvenile hormone activity and it is dependent on nutrition. The mechanism of such specific meta­bolic action of juvenile hormone is based on complete oxidation of the dietary fatty acids, provid­ing metabolic water for larval somatic growth. The excessive amounts of energy created by hy­permetabolism are partly converted to heat, suggesting uncoupling of phosphorylation. Some other specific endocrmological features associated with hypermetabolism have been discussed.

In order to accelerate and artificially induce molting, unoperated crabs, crabs without eye-stalks, Y-organ ectomized and Y-organ-and eyestalkless animals were injected with multiple doses of β-ecdysone. Molting itself was not induced in any case, whereas in double operated animals, both destalked and Y-organless, an acceleration of longer duration of molt preparatory processes was achieved. In all other crabs premolt processes were observed to a much lesser extent, and were only short termed. These findings lead to the conclusion that the Molt Inhibiting Hormone, which is produced in the eyestalks, might not inhibit the action of the Y-organ alone, but acts also onto the peripheral tissues. Furtheron it is concluded that phases of increased susceptibility to the injected hormone might not exist.

The activity of single neurons with constant discharge frequencies in the area around the α-lobe of the mushroom bodies of the bee was recorded intracellularly. The spontaneous discharge frequency of these neurons ranged between 5 and 95 impulses per second. When stimulated, about 80 percent of the neurons responded to at least one of five different sensory modalities: scent; light; air current to the antennae; sugar water applied to the antennae and to the proboscis. 45 percent of the neurons responded to two or more modalities, these multimodal neurons are common in the median protocerebrum of the bee. The differentiated response pattern of the cells does not allow a simple classification. Some of the neurons were identified after the injection of the fluorescent dye Procion yellow. We found 4 neurons with arborizations in the α-lobe and the calyces of the mushroom bodies.

This résumé deals with thermal and nonthermal effects of electromagnetic fields on man. In consideration of two aspects a limitation is necessary. Firstly, there will be discussed only direct and immediate influences on biological cells and tissues, secondly, the treatment is limited to such phenomena, for which biophysical aproximations, based on experimental data, could be developed. Hazards for the human being may occur only by thermal effects within the microwave range. Regarding frequencies below approximately 30 kHz, excitation processes cannot be excluded in exceptional cases. Thermal effects are predominant, between 30 kHz and 100 kHz, before excitations can appear. Furthermore, by comparing the electrically and magnetically induced currents with the naturally flowing currents in man caused by the brain’s and heart’s electrical activity, a “lower boundary-line” was estimated. Regarding electric or magnetic field strengths undercutting this boundary-line, direct effects on the central nervous system may be excluded; other mechanisms should be responsible for demonstrated biological effects. The paper closes referring to some reports - presently discussed - on experimental findings of biological effects, which were observed as a result of the influence of electromagnetic fields of small field strengths.

Eriodictyol-7-glucoside, a flavanone glycoside, was isolated as cream-white needles from the deep-blue fruit skins of Lasianthus japonica, and in the same tissue eriodictyol and scopoletin were also found to occur in a small amount by means of paper chromatography.

The fungus-inoculated leaflets of Dalbergia sericea produce several isoflavonoid phytoalexins including the known pterocarpans, medicarpin and maackiain, ana the isoflavan, vestitol. A fourth, previously undescribed, phytoalexin has been identified as 7-methoxy-2′,4′-dihydroxyisoflavan (neovestitol) by comparison with synthetic material.

Pheromones of the tiger happen to be a mixture of amines which are “fixed” by lipids. One of these, found always in all the four tigers investigated, is phenylethylamine. This may be a biochemical marker at a species level.

Undifferentiated callus cultures of Solanum khasianum contain only traces of steroidal glycoalkaloids, whereas cultures which have just started to generate rootlets contain these com pounds at a level of up to 5.2% of the dry weight. Only 0.34% steroidal glycoalkaloids occur in the seeds; they consist predominantly of solasonine and solanidine as well as traces of an unidentified com pound. Conversely, steroidal glycoalkaloids from tissue cultures starting organogenesis contain the unidentified com pound as a major fraction, in addition to small amounts of solasonine and solanidine.

Ferredoxin-NADP + reductase from the microalga Bumilleriopsis was isolated by a combination of affinity chromatography on a flavodoxin-Sepharose 4 B column and usual purification procedures. Both the elution pattern of the final gel filtration step and of the sodium dodecylsulfate (SDS) disc gel electrophoresis indicate that there are at least two different molecular-weight forms of the reductase, a monomeric form and a dimeric one.

Experimental allergic neuritis was induced in the guinea pig with bovine PNS myelin. Treatment with P 2 protein at the onset of the disease markedly reduced the severity of the clinical signs compared with untreated controls and an­imals treated with CNS myelin basic protein. The mortality was reduced from 94% in the combined control group to 50% in the treated group. Saline was a better vehicle for ad­ministration of the suppressive inoculation than incomplete Freund’s adjuvant.

The steadily increasing global carbon dioxide concentra­tion is further recognized through the decreasing trend of 13 C/ 12 C isotopic ratio in the annual rings of twentieth-cen­tury trees. The decrease is averaged to about 0.012 per mil per year which is attributed not only as due to anthropogen­ic fossil-fuel burning but also to the man’s impact on the land pattern.

A deterministic model of recurrent epidemics is con­structed using a non linear relationship between infection rate and number of contacts. Epidemic waves which are not damped are predicted and a relationship between community size and the period of recurrence is established. A pos­sible explanation of measles outbreaks is suggested.

Nonlinear kinetics in a chemical cell model involving only one substrate (A) and one product (B), two reactions (A → B and A + 2 B → 3 B), and passive diffusion of A and B through the cell wall, can exhibit complex behaviour in­cluding oscillations, bistability (switching) and spiking. One such system is presented, which shows three kinds of re­sponse as depending on the quantity of a stimulus - a sudden input of product B: i. no response; ii. spiking; iii. switching into an alternative steady state - i. e. an “all-or-flip-or-none” response