Band 30, Heft 3-4

With the use of PMR the ribose conform ations have been studied in the tem perature range - 60 to + 40 °C in ND 3 solutions of adenosine (A), guanosine (G), inosine (I), xanthosine (X), purineriboside (P R), 2-am inopurineriboside (2am P R), N6-isopentenyladenosine (N6ipA), 8-bromo-adenosine (8-BrA), 8-bromoguanosine (8-BrG), formycin B (F), tubercidin (T), isopropylidene-adenosine (iA), and isopropylideneguanosine (iG). The analysis is based on the two-state S ⇄ N model of the ribose m oiety proposed by Altona and Sundaralingam . The compounds studied can be classified into two groups: 1. A, I, G, X, PR , 2am PR, N6ipA, and T show a small tem perature dependence of the S ⇄ N equilibrium and [ S ] ~ 0 .6 ; 2. 8-BrA, 8-BrG, and F have a stronger tem perature dependence and [S] ~ 0 .8 . W ithin these two groups the sim ilarities observed are greater than observed in the solid state. Some therm odynam ic conclusions about the S ⇄ N and the syn ⇄ anti equilibria are presented. The results support the previously proposed correlation of the S state of the ribose with the syn conform ation of the base and of the N state of the ribose with the anti conform ation of the base. Furtherm ore, it is derived that the gg rotam er is correlated with the S state of the ribose and therefore stabilizes the syn conformation of the base.

Stereospecific, Hydrogen Labeled The preparation of (R) and (S) [2- 3 H] lactate as well as (S) [2- 3 H] glutam ate via the coupled exchange reaction catalyzed by NAD linked dehydrogenases and NADH : lipoam ide oxidoreductase (diaphorase) is described. The specific radioactivity of the hydrogen ions of the 3 HOH /H 2 O can be obtained in the substrates (100% exchange) if equilibrium isotope effects are disregarded. By the exchange procedure substrates w ith higher specific radioactivity are obtained from positionally [ 3 H] labeled racem ic m ixtures prepared by chemical reductions with [ 3 H] labeled hydrides. The tritium content of one of the enantiom eres is “washed out” into water. As examples are presented the preparation of (R) [2- 3 H] (S) [2-H] malate as well as the corresponding carnitine, glutam ate and (R) and (S) lactate.

The number of l-anilino-8-naphthalene sulphonate (ANS) molecules bound to black phospha­ tidylcholine (PC) and phosphatidylinositol (PI)-membranes was calculated. The fluorescence change of membrane-bound ANS was measured after the addition of positively charged proteins to the same side as ANS. Cytodirome c caused a fluorescence decrease, lysozyme and protam ine an increase. These effects were completely reversible in the case of cytodirome c and lysozyme and only partly reversible in the case of protam ine by increasing the ionic strength. The fluorescence polarization of membrane bound ANS was not significantly changed by protein addition. The results are dis­ cussed with respect to the binding of proteins to probe compared with other fluorescent probes.

The a- and p-states of 3.4-benzpyrene are calculated by use of common param eters and of a param eter set which predicts the quasi-degeneracy of these states. The quasi-degeneracy will be represented by the breakage of pairing theorem and is to be described as a correlation effect, caused by an asymmetric potential. An external field represents an external perturbation, introduced by interaction with the bioreceptor. The calculation shows a sensitive dependence of probability amplitudes for different configurations which participate in the quasi-degenerated resonance states. Thereby the dipole moment may quickly be changed so that excitons are produced. The resonance phenomenon may lead to the carcinogenic effect

A simple but efficient approxim ation method for the integration of differential equations in photokinetics is described. The method can be used in case of weakly and strongly absorbing solutions as well. The rate laws can be calculated as precisely as wanted. The application of this method is not lim ited to simple photoreactions. The procedure and the formalism are shown for the reactions

The field indicating electrochromic 515 nm absorption change has been m easured under different excitation conditions in DCMU poisoned chloroplasts in the presence of benzylviologen as electron acceptor. It has been found : 1. The am plitude of the 515 nm absorption change is nearly completely suppressed under repetitive single turnover flash excitation conditions which kinetically block the back reaction around system II (P. Bennoun, Biochim. Biophys. Acta 216, 357 [1970]). 2. The am plitude of the 515 nm absorption change measured under repetitive single turnover flash excitation conditions which allow the completion of the back reaction during the dark time between the flashes (measuring light beam switched off) amounts in the presence of 2 /um DCMU nearly 50% of the electrochromic 515 nm am plitude obtained in the absence of DCMU. In DCMU poisoned chloroplasts this am plitude is significantly decreased by hydroxylaminhydrochloride, but nearly doubled in the presence of D C IP + ascorbate. 3. The dependence of the 515 nm amplitude on the time t& between the flashes kinetically resembles the back reaction around system II. The time course of the back reaction can be fairly described either by a second order reaction or by a two phase exponential kinetics. 4. 1,3-dinitrobenzene (DNB) or a-bromo-a-benzylmalodinitril (BBMD) reduce the 515 nm am plitude in DCMU poisoned chloroplasts, but seem to influence only slightly the kinetics of the back reaction. 5. The dependence of the 515 nm am plitude on the flash light intensity (the am plitude norm alized to 1 at 100% flash light intensity) is not changed by DNB. Based on these experimental data it has been concluded that in DCMU poisoned chloroplasts the am plitude of the 515 nm absorption change reflects the functional state of photosystem II centers (designated as photoelectric dipole generators II) under suitable excitation conditions. Furtherm ore, it is inferred th at in DCMU poisoned chloroplasts the photoelectric dipole generators II either cooperate (probably as twin-pairs) or exist in two functionally different forms. With respect to BBMD and DNB it is assumed that these agents transform the photoelectric dipole generators II into powerful nonphotochemical quenchers, which significantly reduce the variable fluorescence in DCMU-poisoned chloroplasts

The effect of a-bromo-α-benzylmalodinitril (BBMD) on the oxygen evolution and on the absorption changes at 515 nm and 704 nm has been investigated in spinach chloroplasts. It has been found: 1. Under repetitive flash excitation conditions, where the back reaction around system II is practically excluded for kinetical reasons, BBMD does not restore the 515 nm absorption change in DCMU poisoned chloroplasts. 2. Under single flash excitation conditions, where the back reaction around system II becomes prominent in the presence of DCMU, BBMD moderately inhibits this back reaction. The deleterious effect is pronounced by preillumination with short flashes during the BBMD incubation period of the chloroplasts in the absence of DCMU. 3. Incubation of the chloroplasts with BBMD leads to an activity loss of oxygen evolution which increases with the time td between the repetitive short excitation flashes and with the dark incubation time. Preillumination during the incubation period with BBMD significantly enhances the effect. 4. In the absence of artificial electron acceptors BBMD suppresses in DCMU poisoned chloroplasts the 704 nm absorption change reflecting an internal cyclic electron flow around system I. On the other hand the linear electron transport at system I mediated by DCIP plus ascorbate as electron donor couple and benzylviologen as electron acceptor is not disturbed by BBMD. 5. BBMD incubation of chloroplasts accelerates the decay rate of the field indicating 515 nm absorption change. Based on these experimental findings the conclusion has been drawn, that - in contrast to the assumption of Brandon and Elgersma (Biochim. Biophys. Acta 292, 753 - 762 [1973]) - BBMD does not accept electrons from the primary electron acceptor X 320 of system II in DCMU poisoned chloroplasts. BBMD rather acts as a system I electron acceptor. Furthermore, BBMD exerts deleterious effects on the center of photosystem II, accompanied by a weak ADRY-effect on the water-splitting enzyme system Y. As a tentative explanation of the BBMD-action on system II it is assumed that BBMD transforms the photochemical centers of system II into dissipative energy sinks

2-anilino-1,3,4-thiadiazoles carrying various substituents in the 5-position as well as in the benzene-ring were synthesized. The compounds were tested with rat-liver-mitochondria and with spinach-chloroplasts and revealed to be potent uncouplers of both, oxidative and photosynthetic phosphorylation, with p I 50 -values rangeing from 6.79 to 4.05. At higher concentration all compounds are inhibitors of the Hillreaction. In mitochondria a fair correlation exists between pKa of the acidic NH-group and the uncoupling activity; a maximum is obtained around pKa= 6 .8 , whereas in chloroplasts activity is shifted to more acid pKa-values. The compounds meet the requirements for uncouplers according to the chemi-osmotic theory, being lipophilic weak acids. N-methylation causes total loss of activity in mitochondrial oxidative phosphorylation. The inhibitory action on photosynthetic electron transport is located within photosystem II. This latter activity is almost independent of substituent effects in contrast to uncoupling of either respiratory- or photo-phosphorylation

Different preparative procedures for isolation and purification of plastocyanin were successful to obtain the pure protein from Chlorella vulgaris, Scenedesm us acutus and Spinacia oleracea but not from B um illeriopsis filiform is. Lade of plastocyanin in this alga was further confirmed by the following in comparison with spinach chloroplast material: a. Use of antibodies to block photosynthetic reactions generally dependent on plastocyanin; b. epr spectral assessment; c. treatment of chloroplasts with KCN and amphotericin B ; d. light-induced changes at 553 nm ( = cytochrome f photooxidation). The latter assays indicated that, in contrast to spinach, neither plastocyanin nor cytochrome f ( = Cyt 553) is present in sonified or pyridine treated Bumilleriopsis chloroplasts. Photooxidation of (added) cytochrome 553 takes place not only without plastocyanin but is counteracted by the copper protein

A monospecific antiserum to tobacco plastocyanin agglutinates strom a-free sw ellable chloroplasts from wild type tobacco, (Nicotia na tabacum var. John William’s Broadleaf) from the tobacco aurea mutant Su/su 2 , (Nicotiana tabacum var. Su/su 2 ) from Antirrhinum majus and spinach (Spi-nacia oleracea). In this condition the antiserum inhibits linear photosynthetic electron flow in tobacco and spinach chloroplasts. This inhibition of electron transport as well as the agglutination are not observed if the chloroplasts have been sonicated prior to antiserum addition. This is due to the fact that plastocyanin is removed by ultrasonication. The antiserum stimulates a number of photophosphorylation reactions in tobacco chloroplasts. This stimulation is always larger in the aurea mutant chloroplasts and in chloroplasts from yellow leaf patches of a variegated tobacco mutant (N . tabacum , var. NC95) than in the green type chloroplasts. The stimulation appears to be a consequence of the inhibition of linear electron transport. The antiserum does not affect PMS-mediated cyclic photophosphorylation in tobacco chloroplasts from the wild type whereas the reaction appears stimulated in the tobacco mutant chloroplasts. However, menadione-mediated cyclic photo­ phosphorylation is inhibited upon addition of the antiserum. The same is true for noncyclic photo­ phosphorylation coupled to electron transport in the aerobic system diaminodurene/ascorbate → methylviologen in the presence of N-tetraphenyl-p-phenylenediamine in spinach chloroplasts. If the lamellar system of Antirrhinum and spinach has lost its swellability neither agglutination nor inhibition of electron transport is observed. However, also in this state antibodies to plasto­ cyanin are specifically adsorbed onto the surface of the thylakoid membrane. This state which is characterized by a morphologically well preserved lamellar system is realized in chloroplast prepa­ rations from Antirrhinum and spinach and is termed stroma-freed, chloroplasts. In both states of the molecular structure of the thylakoid membrane, plastocyanin is located in the outer surface of the thylakoid. However, it cannot be excluded that functioning plastocyanin is also located in the interior of the thylakoid membrane.

In freely suspended cells of parsley (Petroselinum crispum ) protein synthesis is inhibited nearly totally by 5 /ug/ml cycloheximide within 10 min. This very low dose has a slight effect on the rRNA synthesis too. During an incubation period of 60 min with [ 32 P] orthophosphate in the presence of the inhibitor (5 /ugjml) at least 65 - 70% mature rRNA are synthesized compared with the control. After 120 min the synthesis is progressively reduced to 60 - 65%, and after 240 min to 30-40% . Cycloheximide causes a delay of the processing of the precursor RNA species leading to an accumulation of these components. In addition to the 2.3 x 10® daltons RNA, normally detectable in pulse experiments, two further precursor molecules do emerge which under normal circumstances apparently are shortlived. Their molecular weights are 2.0 x 10® and 0.9 x 10® daltons. The pulse-chase technique and cell fractionation into nuclear and ribosomal parts enables us to demonstrate a rapid transfer of labelled 18S and 25S RNA during a 15 min chase treatment to the mature cytoplasmic ribosomes. Under these conditions no differential transport of the two components takes place. The cells possess a pool of proteins. Therefore the formation of RNP-particles or ribosomes respectively and the transport from the nucleus to the cytoplasm are independent from protein synthesis for some time

Wachstum und Stickstoff-Ausscheidung von Anabaena solitaria bei Züchtung in Süß­ wasser bzw. in Mischungen aus Süß-und Seewasser sowie unter Zusatz von Fe, Mn und Mo Nitrogen Excretion by Nitrogen Fixing Blue-green Algae, II Growth and Nitrogen Excretion of Anabaena solitaria Grown in Freshwater and in Mixtures of Freshwater and Seawater, as Well as with Fe, Mn, and Mo Added to the Nutrient Medium Nitrogen Excretion, Nitrogen Fixing Blue-green Algae, Anabaena solitaria, Blue-green Algae The nitrogen fixing blue-green alga, Anabaena solitaria, was grown in freshwater and in mixtures of freshwater and seawater. Freshwater and a 5% mixture (95 volumes of freshwater and 5 volumes of seawater) proved to be most suitable: Growth (as expressed by the formation of chlorophylls; approx. 1.9 u g chlorophyll/ml) was comparatively high. The nitrogen content of the nutrient medium was increased to 750 - 760 //mol N/1. Upon addition of appropriate amounts of FeCl 3 , MnCl 2 , and Na 2 MoO 4 , the nitrogen content reached 1060 -1080//mol N /1, whereas the chlorophyll formation remained at approximately the same level. Thus Fe, Mn, and Mo appear to have a stimulating effect on nitrogen excretion by Anabaena solitaria. Under the conditions de­ scribed, this organism may be suitable for the mass production of algae.

The total combined nitrogen (850 //mol N/1) excreted by the nitrogen fixing blue-green alga, A nabaena cylin drica, during growth in an artificial nutrient medium, was subsequently utilized to a different degree by various green algae. Two species of filamentous green algae, Chlorhormidium spec, (strain I) and Chlorhorm idium spec, (strain II), proved to be most suitable: When grown in the above nitrogen-enriched medium after removal of A nabaena cylindrica, they lowered the nitrogen level in the medium from 850 to 460 - 600//mol N/1 within 29 days. When another nitrogen fixing blue-green alga, Anabaena solitaria, was grown under unsterile conditions in mixtures of freshwater and seawater with trace elements (Fe, Mn, and Mo) added, nitrogen levels of 1000 - 1060 //mol N/1 were obtained. These levels were subsequently lowered to 530 - 570 //mol N/1 by the two species of Chlorhorm idium . Under appropriate growth conditions, the combined nitrogen excreted by Anabaena solitaria can possibly be utilized as a nitrogen source for green algae

In order to increase the efficiency of different mRNAs from wheat seedlings in carrying out cell-free protein synthesis in the wheat system, efforts were made to remove endogenous mRNA. In this direction, we checked the possibility of using immobilized RNAase. Treatment of the cellfree system or its components with this enzyme caused a large decrease in the efficiency of poly Udirected incorporation of labeled amino acids. This effect did not coincide with an equivalent degradation of RNA, as has been shown by analysis of ribosomes and polysomes. The results are discussed in the light of recent findings of some authors

[ 35 S] L-Methionine and [methyl- 14 C] ʟ-methionine were fed to shoots of Matthiola annua and Matthiola sinuata. The label from both precursors was incorporated to a high degree into 4-methylsulfinyl- 3-butenylglucosinolate, the main mustard oil glucoside of M atth iola species. Two homologues of methionine, homomethionine and 2-amino-6-methylthiocaproic acid, were also labelled in these experiments. 2-Amino-6-methylthiocaproic acid, deriving from methionine via homomethionine by two successive C 1 -chain elongation steps, was higher plants

The phase shifting action of low temperature pulses of 6 °C and 2 h duration administered to the various phases of the Drosophila pseudoobscura circadian rhythm and the action of light pulses given 30 min after the beginning of these low temperature pulses have been investigated. The phase response curve obtained from experiments with light pulses during low temperature cannot be ex­ plained on the basis of a straightforward and sequential phase shifting of the oscillation by the various transitions in the pulses. The response curve, after the slight phase shifting action of the temperature pulses is corrected for, resembles the standard phase response curve 4 for light pulses (at 20 °C) in its wave form but not in its time course. Our curve is shifted in time in a manner that indicates that the light pulses accompanying the low temperature pulses arrived at phase points 1.5 h later than the actual phases at which they were given. We attribute this delay to a slowing down of the information that is apparently transmitted by a process that is temperature dependent.

From purchasable yeast small cells are preparated by repeated centrifugation. They grow and multiply in a good synchronisation

Total RNA, extracted from synchronously growing yeast cells by the method of Georgiev-Mantieva, was separated by columns of methylated albumin on Kieselgur (MAK). By comparison with definited RNA’s in discelectrophorese and after pulse labelling with [ 3 H] methionine the following fractions are identified: t-RNA, 5.8S RNA, m-RNA, 18S and 25S r-RNA and their precursors 20S, 27S and 35S. High molecular fractions of RNA between 40S and 70S were also found

Neurospora crassa, Biosynthesis, ᴅ-Lysine, ʟ-Lysine, Role of ʟ-Pipecolic Acid Neurospora crassa converts ᴅ-lysine to ʟ-pipecolic acid and the latter to ʟ-lysine by a pathway outlined herein and different from mechanisms hitherto known to be involved in interconversions of enantiomers of amino acids.

1. Dexamethasone phosphate causes approximately a threefold increase of the tyrosine-a-ketoglutarate transaminase in the culture of RLC cells. 2. The induction of the enzyme depends on the presence of L-tyrosine. Omission of L-leucine or L-tryptophan, respectively, has no effect. 3. Omission of L-tyrosine influences the activity of the lactate dehydrogenase and malate dehydrogenase not at all and that of the glucose-6-phosphate-dehydrogenase only to a small extent. 4. In the absence of ʟ-tyrosine an super-induction takes also place by actinomycin

Testosterone, Androst-4-en-3,17-dione, Enzyme Induction, S trep to m yces hydrogenans After cultivation of S trep to m yces hydrogenan s in the presence of 3H-labelled testosterone, radio­ active steroids were extracted separately from the cytosolic, ribosomal and cell wall-membrane fraction of the cells and from the culture medium, respectively.. The separation of the steroids was performed by one-and two-dimensional thin layer chromatography (TLC). The identification of the main metabolites was achieved by crystallization to constant specific radioactivity, specific staining procedures and acetylation. The oxidation of testosterone to androst-4-en-3,17-dione is by far the predominating reaction, which is almost finished after 3 h cultivation. Androst-4-en-3,17-dione is mainly transferred into the culture medium and partly accumulated within the cell wall-membrane fraction. High polar steroid metabolites and androstane derivatives are present in very small amounts only.

The site of the pulse regeneration in myelinated nerve is generally assumed to be the unmyelinated part of the axon membrane in the Ranvier node. To check this, a micro-irradiation technique using laser pulses (λ = 347 nm, t = 2 0 ns) was used to produce morphological lesions of about 1 /(m diameter in various regions of the Ranvier node. The electro-physiological functions were monitored parallel to the irradiation. Depending on the localization of the lesions two types of changes in these functions were observed: 1. If a definite site in the paranodal myelin sheath was damaged without affecting the axon, an action potential could no longer be elicited, although the resting potential as well as the stationary current-voltage behaviour remained unchanged. 2. A damage of the axon resulted in a break down of membrane potential and resistance. In most of the cases the excitability recovered after spontaneous or current induced restitution of the membrane resting potential and resistance. These observations indicate, that structures in the paranodal region are vital for the Na + -activation and inactivation. The membrane potential and stationary current-voltage behaviour can be attributed to the axon membrane. A new hypothesis concerning the mechanism of the Na+-activationinactivation process is suggested

Multiple binding interactions between odor molecules and acceptors are formulated by means of the Boltzmann statistics and intermolecular bond energies. Number, spatial arrangement and electronic properties of binding positions of the acceptor can be defined such that the specificity of sex pheromone receptors in male noctuid moths is quantitatively described.

Pheromones, Olfactory Receptors, Structure-response Relationships, Lepidoptera Electroantennogram (EAG) data reflecting response spectra of male pheromone receptors have been analyzed for 16 species of Noctuidae (Lepidoptera). The test compounds included 100 phero­ mone analogues, altered in chain length, in position and configuration of double bond(s), and in the functional end groups. On comparison of amounts of substance required to elicit an equivalent EAG response, a single compound was determined to be most effective on a given species; these structures, either known or proposed as the natural sex pheromones of the species, were cis-1-dodecen-1-yl acetate, cis-7-tetradecen-1-yl acetate, cts-9-tetradecen-1-yl acetate, Jrarcs-9-tetradecen-1-yl acetate, cis-ll-hexadecen-l-yl acetate, cis-9, trans-12-tetradecadien-l-yl acetate, cis-9-tetradecen-1-yl formate, and cts-9-tetradecen-1-ol, respectively. Elongation (shortening) of the chain by 1 or 2 methylene groups, the movement of a double bond 1 carbon from the optimum, a change to the opposite geometrical isomer, or the introduction of a second double bond invariably reduced EAG responses to 1.8 to 56 times below that observed with the most stimulating compound, in all 16 species. Further alterations in chain length or in double bond position caused even greater reduc­ tion in activity, as did certain changes in end group (Tables I and II). A set of distinct rules could be derived from these structure-response relationships; one of these rules concerns the optimum position of the double bond(s) in relation to chain length, and another one the ratios in activity values produced by end group variations, irrespective of chain length. The same rules described here for 16 noctuid species held also for the structure-response relationships observed within various additional groups of Lepidoptera. From EAG values determined in this study, an attempt has been made to calculate physico­ chemical propteries of underlying acceptor structures.

Lysozyme relaxation times T 1 and T 2 have been measured. Methyl groups T 1 are sensitive to thermal denaturation of the lysozyme. The exchange of the water molecules between bounded and free is slow

In addition to known constituents have been isolated from the leaves of Arctostaphylosuvaursi quercetine-β-D- (6-O-galloyl-galactoside), two isomeric quercetine-3-arabinosides and myricetine-β-ᴅ-galactoside

Carotenoids, Porter-Lincoln-Series, Anthurus, Fungi From different phases of development of the fungus A nthurus archeri carotenoids of the Porter-Lincoln-series (phytoene, phytofluene, β-carotene, neurosporene, and lycopene) have been isolated.

Species of Zygaena (Lepidoptera) have been fed with leaves of Lathyrus pratensis rich in chlorophylls and carotenoids. The metabolism of the pigments was followed in eggs, larvae, pupae, and imagines of the insects. No chlorophylls, only lutein - the main carotenoid of the food plants - was stored in the animals. Traces of α-zeacarotene, absent in plants, could be found in eggs and larvae

Wheat, DNA-synthesis, Irradiation Plants, arising from irradiated (300 kR) caryopses of wheat, exhibit a low incorporation of [3H] thymidine into the DNA, which, as shown by sedimentation on sucrose gradients, does not indicate tendencies of normalization.

The ribosomal RNA of the gametophyte of Allomyces arbuscula contains two components with sedimentation coefficients of approximately 25S and 18S. The percent base composition of 25S rRNA is 31/28/24/17 (U/G/A/C), that of 18S rRNA 34/28/22/16

Human metaphase chromosomes A 1 and A 3 did bind more tritiated poly-L-lysine ([ 3 H]PL) when they were isolated from lymphocyte cultures treated with LiCl rather than with NaCl or KCl. A 2 chromosome did not show this differential behavior and in all three cases did bind more [ 3 H] PL than the control A 2 chromosome. The effect was dependent on the time of exposure of cells to the salts in tissue culture and on the degree of chromosomal contraction. The observed differences in [ 3 H] PL binding are probably due to differences in surface morphology of the three chromosomes caused by treatment with alkali metal salts

Intracellular recordings show that the receptors and second-order interneurons of the dragonfly compound eye change their sensitivity in response to maintained illumination. Comparison of receptor with interneuron shows that neural mechanisms act to ensure that the modulation of interneuron membrane potential that is set up by contrast changes is independent of background intensity.

Mice could be protected against Friend leukemia virus infection by inoculation with highly purified viral glycoprotein GP 71 or its specific antiserum