Volume 34, Issue 12

The solution conformation of adenosine(β)ribosides modified at the 2′, 3′ or 5′ position is derived from the analysis of the HRNMR spectra of the ribose protons. The conformational equilibria of the furanoside rings are described by the two state N ↔ S model introduced by Altona and Sundaralingam. The new compounds studied are: 2′-thiobenzoyl-2′-deoxyadenosine, 3′-thio-3′-deoxyadenosine, 2′-chloro-2′-deoxyadenosine, 3′-chloro-3′-deoxyadenosine, 2′-bromo- 2′-deoxyadenosine, 3′-bromo-3′-deoxyadenosine, 2′-O-methyladenosine, 3′-O-methyl-adenosine, 2 , -deoxy-3 , -O-methyladenosine, 5′-amino-5′-deoxyadenosine, 5′-acido-5′-deoxyadenosine, and 5′-chloro-5′-deoxyadenosine. The emphasis in this work is to study systematically the influence of the different substituents upon the conformational equilibria of the sugar. It is found that any substitution at the 2′ position stabilizes the S-conformer. An even more pronounced stabilization of the A-conformer in the 3′ substituted analogs is observed. The equilibrium changes in these classes of compounds can neither be correlated quantitatively with electronegativity differences nor with sterical differences between the various substituents. Substitution at the 5′ position influences the N ↔ S equilibrium only slightly, but has significant effects upon the conformational preferences of the exocyclic 5′-CH 2 R 3 group.

Ramachandran-type calculations are performed for conformations of bilin chromophores pres­ent in the biliproteins phycocyanin, phycoerythrin and phytochrome. The atomic coordinates are taken from x-ray data of crystalline model compounds, namely biliverdin for pyrrole rings B, C, D and substituted succinimides for the hydrogenated ring A including a thioether containing β-sub­stituent. Maxima and minima for steric hindrance are calculated for rotation of the thioether side chain, the rotation of pyrrole rings at single bonds (syn-anti-forms) and at double bonds (Z-E-isomers) of the methine bridges. Whereas quasi-planar structures are possible for all syn, Z-forms, only twisted structures are possible if anti, E-forms are considered. The relevance for the bilin con­formations of native biliproteins and of the P r ⇌ P fr phototransformation is discussed.

The use of field desorption mass spectrometry is demonstrated not only for molecular weight determination but also for detailed structural analysis of large, underivatized natural products. Owing to cationization by small alkali salt impurities, saponins carrying one to four sugar units gave abundant quasimolecular ions. In addition, the observed sequence-specific fragment ions reflected the complete sequence of the sugar units in the oligoglycosides. This fragmentation of the oligosaccharidic moiety of the natural products was interpreted by analogy with acidic solvolysis, a mechanism well established in solution chemistry. Of particular interest was a first com­parison of the field desorption mass spectra obtained from two different commercially available instruments operated by different groups in order to give an estimate of interlaboratory reproducibility in field desorption mass spectrometry.

15 N-NMR chemical shifts, spin-lattice, and spin-spin relaxation times of the four pyrrole nitrogen nuclei in complexes of low-spin ferritetraphenylporphyrin with pyridine and 1-methylimidazole in chloroform have been studied. Although deviations from an axial symmetry are observed at 4K by EPR and ENDOR spectroscopy, only one 15 N-NMR absorption signal can be detected at T < 200 K indicating that rhombic distortions are averaged out at temperatures where NMR is observed. From an analysis of the 15 N-NMR relaxation behavior it was possible to determine the magnitude of the hyperfine coupling constant A, from which the Fermi contact term to the chem­ical shift was obtained. For a calculation of the pseudocontact shift, which is of the same size as the contact term, not only the shifts arising from the ‘orbital term’ but also bonding effects be­tween the pyrrole nitrogen orbitals and the Fe 3+ orbitals have to be considered.

The detailed structure of the CO 2 Hb binding curve is of considerable physiological interest, because the carbamino derivates, which are formed by the reaction of CO 2 with Hb, are respon­sible for the well known Haldane effect. Under physiological conditions CO 2 binds to the four terminal NH 2 -groups of the protein chains of Hb and it is generally assumed, that there exists no cooperativity between these groups. To examine whether this assumption is correct or not, we have measured the CO 2 Hb binding curve over a wide PCO 2 -range (from 0 kPa to about 70 kPa) by using 13 C-NMR spectrometry. Morrow and coworkers (1976) have shown that carbamino-Hb causes a specific NMR signal. The quantitative analysis of the NMR spectra were done according to the method of internal standard. By analyzing mixtures of known composition, we were able to show that this method is working. So we had to use the following equation: Z is the CO 2 saturation of Hb, I is the intensity of the carbamino signal, and I Hb is the intensity of the carbons of Hb, which are involved in the amide binding. (I/I Hb ) max is (I/I Hb ) at high PCO 2 , where Hb is completely saturated by CO 2 . For our experiments we used solutions of human desoxygenated Hb, which were equilibrated with a mixture of N 2 and CO 2 . The CO 2 contained 90% 13 C-isotope. The pH was adjusted by titration to 7.2. The NMR measurements were mainly done with a Varian XL 100 NMR spec­trometer. The CO 2 Hb binding curve, we have measured, is S-shaped and has an average Hill value (n̅) of 2.1. This result is quite striking with respect to the findings of other groups. A Hill value of 2.1 proves that CO 2 like O 2 binds to Hb in a cooperative manner. The discrepancy to the results of other groups may be explained by the fact that these authors measured the CO 2 Hb binding curve only at comparatively low PCO 2 . In our opinion one can only get reliable n-values from the whole CO 2 Hb binding curve.

Cerasine having a molecular weight of 800 differs chemically from phrenosine only in the hydroxyl group attached to the fatty acid tail which is replaced by a hydrogen atom. Nevertheless, remarkable differences between both cerebrosides are detected in the lamellae periodicities. In the range of 23 - 66 °C just one single (instead of two) structure with a similar subcell to the triclinic one component of phrenosine is detected. Between 66 and 87 °C three new components (instead of one in phrenosine) appear. Two of the structures are similar to the two phrenosine-components at low temperature and the tilt angles of their chains with respect to the basal planes can explain the stabilizing capacity of the 201 and 301 netplanes of the paraffin-like subcells respectively. These lattice planes are parallely aligned to the surfaces of the lamellae. The long period of 58 Å of component II cannot be explained in such a wav. This period persits upto 105 °C and coexists from 87 °C with a new component showing a 40 Å-periodicity, which cannot either be explained in the above manner. Paracrystalline distortions of the arrangement of the bilayers can be justified by orientational disorder of the galactose heads.

Hoya lacunosa leaves contain some main C-glycosylflavonoids, which were identified as: 6-C- arabinosyl 8-C-glucosylapigenin (isoschaftoside), 6-C-glucosyl 8-C-arabinosylapigenin (schaftosi- de) and 6,8-di-C-arabinosylapigenin. In the latex triterpenols were found, often both free and in ester form, of which β-amyrin, α-amyrin, lupeol, 24-methylenecycloartanol, obtusifoliol and cycloeucalenol were identified in the free alcohol fraction. The esters, forming the major part of the to­tal lipid fraction, were solely acetates of some of the above mentioned alcohols.

Two new compounds derived from coniferyl alcohol have been isolated from Herpetospermum caudigerum Wall. Their structures have been established by spectral analysis (UV, PMR, CMR and MS).

A fast, sensitive high performance thin-layer chromatographic method for the determination of α-, β-, and γ-amanitin in crude, methanolic extracts of Amanita phalloides is described. The limit of detection is 50 ng of each amanitin. With this method amanitin was determined in 24 pooled samples of Amanita phalloides, collect­ed between 1970 and 1977 in Germany and Switzerland. The total amanitin content varied be­tween 2010 and 7300 mg/kg dry weight and the average value was 4430 mg/kg of which 43% was α-amanitin, 49% β-amanitin and 8% γ-amanitin. The origin of the fungi hardly influenced their amanitin content: in samples collected during the same year at different sites it fluctuated within a factor of 1.7. The amanitin content of samples from the same site, but collected in different years, maximally varied within a factor of 3.7. The partial decomposition of amanitins during prolonged storage of the lyophilized samples undoubtedly contributed to this variation. Phalloidin, which was determined by conventional thin-layer-chromatography, could not be de­tected in a sample from 1970, whereas its concentration in material collected during 1977 amount­ed to 2400 mg/kg dry weight. The toxicity of the samples (LD 50 of lyophilized defatted methanolic extracts intravenously for mice) varied within a factor of 2.5.

During the irradiation of aqueous solution of insulin (pH 1.8) the decrease of original insulin molecules and the formation of radiation aggregates of insulin was studied in dependence on the concentration of irradiation solution, on the doses and conditions of irradiation (oxygenated and oxygen-free atmosphere, the presence of t-butanol, addition of [ 14 C] amino acids). From the results obtained and results published earlier it may be assumed that in irradiated solution on insulin new covalent bonds between insulin molecules are formed at tyrosyl, phenylalanyl and cystyl radicals; these radicals are formed by the action of both direct and indirect effect (at present pH 1.8 mainly of H atoms).

Protamine and polyarginine had bacteriolytic effects indicating their primary sites of action as being wall components and showing bacterial diversity genetically determined. Shake-incubation was required in producing cell-lysis. Studies on Bacillus subtilis revealed a high polycation multiplicity per cell in lytic event displaying multihit lysing kinetics; bacteriolysis was inhibited by trypsin, pronase, purified polyanionic wall polysaccharide, and by dissociative actions of salt hypermolarities used in isolation of nucleic acids. The inactivation of polycationlytic abilities dur­ing bacteriolysis was accompanied by modifications in electrophoretic running of protamine and polyarginine. It is suggested as mechanism of cell-lysis, the multiple zonal surface condensations of polyanionic wall components by basic polypeptides, likely similar with chromatin DNA picnosis. This analogy is discussed.

Calf satellite I DNA digested with EcoRI and PstI gives three fragments 643, 621 and 83 bp long. Two of them , the 643 and 621 bp were cloned using pBR 322 vector and analyzed by means of the MspI and Haelll restriction enzymes.

The interaction of the antibiotic tetracycline with a few metal ions, esp. Cu(II), in different so l­ vents has been investigated by means of IR, ESR, and UV /VIS spectroscopy. It could be shown that the site of complexation depends on the solvent used. In DMSO the interaction occurs mainly via the A ring. In water (pH = 5.7) and octanol, the A chromophore as well as the BCD entity of the molecule are involved in complexation. If the tetracycline concentration exceeds the Cu(II) concentration, a 2 : 1 (antibiotic : Cu(II)) complex seems to be formed, at least in DMSO.

ʟ-α-Aminooxy-β-phenylpropionic acid (AOPP), a potent competitive inhibitor of phenylalanine ammonia-lyase (PAL), blocked light-induced phenylpropanoid synthesis in excised buckwheat hypocotyls and produced an up to 40-fold increase in the endogenous phenylalanine concentra­tion, while the level of all other amino acids was hardly affected. After a 24 h incubation in the light in the presence of 0.3 or 1 mᴍ AOPP phenylalanine alone constituted about 25% of the total soluble amino acids, compared to appr. 1% in the controls. In the presence of AOPP illuminated hypocotyls accumulated nearly 3 times more phenylala­nine than hypocotyls kept in the dark, indicating an enhancing effect of light on the flow of carbon through the shikimate pathway. Exogenously added [ 14 C] phenylalanine was extensively metab­olized by control tissue, but accumulated in AOPP treated tissue. In the presence of AOPP radio­activity from [ 14 C] shikimate accumulated predominantly in phenylalanine, and the flow of shi­kimate into tyrosine and phenylalanine was not affected by the inhibitor. Therefore, under these conditions no feedback control of phenylalanine and tyrosine synthesis from shikimate is apparent in buckwheat hypocotyls.

The antitumor activity of molybdocene dichloride is tested against Ehrlich ascites tumor in CF 1 mice. The application of 75 or 100 mg/kg 24 h after transplantation achieves 100% tumor inhibi­tion until day 30. Following the d 0 and d 1 metallocene dichlorides of titanium and vanadium, molybdocene dichloride is the First analogous d 2 system revealing similar antineoplastic properties.

Reduction in the amounts of activity of the first enzyme, aspartokinase (EC 2.7.2.4) and two branch-point enzymes, dihydrodipicolinic acid synthase (EC 4.2.1.52) and homoserine dehydrogenase (EC 1.1.1.3), located in the pathway for the synthesis of aspartate-family amino acids, occurred when cell suspension cultures of Daucus carota L. var. Danvers were grown in media containing 2 mᴍ threonine or 2 mᴍ lysine, endproducts of the pathway. Activity of the lysine-sensitive form of aspartokinase was decreased when cells were grown in medium containing lysine and the activity of the threonine-sensitive form was decreased when cells were grown in medium containing threonine. Activity of the branch-point enzyme leading to threonine synthesis, homoserine dehydrogenase, was decreased up to 70% in specific activity (units/mg protein) and relative activity (units/g fresh weight) when cells were grown in media containing lysine or threonine. Threonine had no effect on the relative activity of dihydrodipicolinic acid synthase, but decreased its specific activity. Lysine decreased the relative activity of the synthase by up to 40%, but had little effect on its specific activity. The decreased activities of the enzymes were apparently not due to binding of the inhibitory amino acids to the enzymes since homogenization of cells in buffer with 2 mᴍ lysine and threonine did not decrease the measurable enzyme activities. These and other results presented suggest that both forms of the aspartokinase activity and homoserine dehydrogenase activity can be altered by supplementing the growth medium with lysine or threonine.

The catalytic (C) subunit of isoenzyme II of cyclic AMP-dependent protein kinase from rat muscle, purified to apparent homogeneity, was investigated for some of its basic properties and factors that influence its activity. The properties were found to resemble those of C subunits of both isoenzymes I and II from various other tissues of different species. This concerns the molecular weight estimate (about 37 k), ultraviolet light absorption spectrum, isoelectric point (pH 9.0 ± 0.2), the apparent K M values for histone and protamine (for both substrates ≤ 10 μᴍ) and the apparent K M for cosubstrate ATP (3-4 μᴍ). The enzyme is sensitive to the heat- stable inhibitory protein. The enzyme activity is stable up to 40 °C but becomes destroyed at higher temperatures; the half life at 50 °C is slightly less than 1 min, and at ≥ 60 °C activity is nullified within 1 min. Activity is lost on freezing and thawing. Substrate histone does not improve temperature stability; cosubstrate ATP in absence of Mg 2+ decreases, but in presence of Mg 2+ increases stability. The optimum pH of enzyme activity is at pH 6.8 for histone and pH 7.8 for protamine phosphoryla­tion. The enzyme becomes irreversibly inactivated at pH values below 5. For activity, the enzyme has absolute requirement for a divalent metal ion, highest activity is found in presence of Mg 2+ or Co 2+ ; the optima are at 5-10 mᴍ (half maximum at 0.9 mᴍ) and 0.5-0.8 mᴍ (half maximum at 0.25 mᴍ) for Mg 2+ and Co 2+ , respectively. None of the various other metal ions tested were nearly as effective as these two. Ca 2+ antagonized Mg 2+ . A considerable effect on activity by ionic strength was observed. In dependence on the substrate used, activity is influenced strongly by some anions and zwitterions. E. g. in presence of acetate, histone phosphorylation is by a factor of 3-4 higher than in presence of sulfate, whereas protamine phosphorylation is only half that in presence of sulfate. Roughly the following order of enzyme activity in presence of the respective buffer system was found: MOPS (100%) ≥ TES (95%) ≅ HEPES > MES (65%) ≅ acetate ⪢ ADA (20%) > phosphate (15%) > TRIS • maleate (7%).

The light-driven incorporation of amino acids by isolated spinach chloroplasts is inhibited by the M component (VM) and not by the S component (VS) of virginiamycin. This inhibitory effect is partially reversible. In chloroplast extracts, poly(U)-directed polyphenylalanine formation is strongly inhibited by VM and not by VS. The in vivo synergistic effect of VM and VS observed in bacteria and algae, does not occur in isolated chloroplasts and chloroplast extracts.

Binding of antibodies to proteins and lipids onto fragments of the thylakoid membrane was stu­died and compared with the binding of antibodies by stroma-freed chloroplasts. The membrane fragments were prepared from stroma-free chloroplasts by ultrasonication and fractional centrifugation. The fragments have an average diameter of 200 A. Their thickness corresponds to that of the thylakoid membrane. The membrane fragments adsorb out of an antiserum to lipids approximately the same amount of antibodies as out of an antiserum to proteins. In comparison to this, stroma-free chloroplasts bind 4 times more antibodies to proteins than to lipids. From this it follows that the major part of the lipids is located in the membrane surface which is directed towards the inside or is located inside the membrane. As the chemical analysis has shown these results are not caused by an altered chemical composition of the membrane fragments. Despite the fact that membrane proteins bind considerably less protein antibodies than stroma-free chloroplasts, the antibody binding in membrane fragment might be considerably increased for certain proteins such as a polypeptide with an apparent molecular weight 24000 and cytochrome f. Antibodies to the major components of the lipid mixture, such as to monogalactosyl diglyceride, trigalactosyl diglyceride, sulfoquinovosyl diglyceride and phosphatidyl glycerol are 3 to 4 times more bound by membrane fragments than by stroma-free chloroplasts. From these results it is concluded that the thylakoid membrane surface directed towards the inside is preponderently composed of lipids whereas the surface directed towards the outside consists only by 10 to 15% of lipids.

Two β-Carotene pools were obtained in the chloroplast. It is concluded that one pool is very small like α-carotene and responsible exclusively for the biosynthesis of β-ionone-xanthophylls. The other β-carotene pool is proposed to be the one, that is located close to photosystem I and is involved in photosynthesis as a light protecting agent for chlorophylls against photo-oxidation. Furthermore evidence is given that both β-carotene pools are synthesized by independent biosyn thetic pathways.

Representatives of phycobiliprotein-containing algae such as Anabaena cylindrica, Anacystis ni- dulans, Gloeotrichia echinulata (Cyanophyceae), Chroomonas spec., Hemiselmis rufescens, Rhodomonas spec. (Cryptophyceae), Porphyridium cruentum, Rhodella violacea (Rhodophyceae) along with the unicellular Cyanidium caldarium (unspecified systematic status) have been investigated for their typical photoassimilatory accumulation products. While the red algal species synthesize a rather specific heteroside, 2-O-ᴅ-glycerol-α-ᴅ-galactopyranoside (= floridoside), not encountered in the other species analyzed, blue-green algae accumulate fructose, glucose, and sucrose, while the cryptomonads accumulate only glucose and. to a lesser extent, fructose. Cyanidium synthesizes neither disaccharides, nor a heteroside, but shows rapid 14 C-labelling of fructose and glucose. These results are compared with further biochemical and structural findings and are discussed with emphasis on chemotaxonomic implications. Cyanidium caldarium is proposed as an endocyanome consisting of a single endocyanella providing the functions of a chromatophore in a colourless (apoplastidal algal?) host cell.

Cell division of isolated mesophyll cells of Calystegia sepium can be made sensitive to long-wave UV (LUV) by treatment with 8-methoxypsoralen (8-MP). The inhibition of cell division de­ pends on 8-MP concentration and the length of light exposure. Only the simultaneous presence of 8-MP and LUV gives effective photosensibilization. Cells treated with 8-MP in the dark can be made non-sensitive to LUV by washing out the furocoumarin prior to irradiation. The furocoumarins may offer a means of cell selection.

An antiserum to synthetic Zeaxanthin inhibits photosynthetic electron transport on the oxygen-evolving side of photosystem II in tobacco chloroplasts and thylakoids of the filamentous blue-green alga Oscillatoria chalybea. The inhibition site lies for both species between the site of electron donation of water or tetramethyl benzidine and that of diphenyl carbazide or manganese II ions. Typical photosystem I reactions are not impaired by the antiserum. The effect of the antiserum concerning the inhibition site is practically identical to that of the earlier described antiserum to violaxanthin. However, the degree of inhibition seems to be generally somewhat lower with the antiserum to Zeaxanthin, than with that to violaxanthin which hints at a lesser accessibility of zeaxanthin, in the tylakoid membrane in comparison to violaxanthin. In the course of these investigations new evidence was obtained that the oxygen-evolving side of the electron transport scheme is differently organized in Oscillatoria chalybea when compared to tobacco chloroplasts. Thus, the silicomolybdate reduction with water as the electron donor is sen­sitive to DCMU in these algae.

The plasmalemma of thallus cells of the aquatic liverwort, Riccia fluitans, is reversibly depolar­ized by ʟ- and ᴅ-serine. At 0.1 mᴍ K + in the medium, the depolarization saturates at 50 mV; half-maximal depolarization occurs at 13 μᴍ ʟ-serine and 30 μᴍ ᴅ-serine, respectively. Uptake of 14 C-­labelled ʟ-serine depends upon the K + concentration and is sensitive to the membrane potential as indicated by its reduction through 1 mᴍ sodium cyanide. We propose that serine binds to and is transported by an electrogenic carrier. However, an interaction of serine with K + channels of the membrane seems also possible.

Na + , K + -ATPase of the plasma membrane isolated from sheep kidney medulla exhibits functio­nal asymmetry for the cardiac glycoside ouabain. In this vesicular membrane preparation the rate of binding of ouabain was slow (time constant > 60 min) when the vesicles were incubated in the presence of isotonic sucrose. Upon treatment of the preparation with hypoosmotic shock or phos­pholipase A the initial rate of ouabain binding was enhanced at least 3 fold. In equilibrium a concentration of the ouabain-enzyme-complex was obtained which was about twofold that of the untreated vesicles. This result suggests two types of ouabain binding sites with an approximate stoichiometry of 1 to 1. The stoichiometry seems to be maintained at high concentrations of ouabain where binding curves show a biphasic time course. Additional information about hetero­geneity of binding sites comes through experiments in which the vesicles were treated with Mg 2+ prior to the addition of ouabain. A minor fraction of the binding sites were occupied by ouabain only after longtime incubation with Mg 2+ .

Seeds of cucumber fruits at a late stage of ripening were analyzed for microbodies and micro­body components. On isopycnic density gradient centrifugation of homogenates in the presence of EDTA, several particulate fractions were obtained: a light membraneous fraction (density d = 1.09-1.11 kg × 1 -1 ), a mitochondria-enriched fraction (d = 1.21 kg × 1 -1 ), a microbody-enriched fraction (d = 1.23 kg × 1 -1 ), and a protein body fraction (d= 1.26 - 1.29 kg × 1 -1 ). Microbo­dies were revealed by exactly coinciding peaks of malate synthase, catalase and crotonase; small proportions of citrate synthase and malate dehydrogenase were also present in this zone. Isocitrate lyase activity, however, did not occur in the seeds at this stage. The examination of enzyme activi­ties indicated the presence of microbodies which cannot function as competent glyoxysomes be­cause of the lack of isocitrate lyase. Moreover, de novo synthesis from [ 3 H] leucine could be de­monstrated for malate synthase by means of immunoprecipitation of newly synthesized malate synthase and subsequent electrophoretic analysis.

Malate synthase is synthesized de novo in the very early phase of germination. Its molecular and immunological properties do not differ from those of malate synthase from fully developed cotyledons. Radioactive leucine was administered to dry seeds of cucumber, and its incorporation into proteins of cotyledons was examined after 2 days of germination. The specific radioactivity of malate synthase, purified by immunoprecipitation and electrophoresis on polyacrylamide gel, was only 1/20 the average value of the total albumin fraction. The minimal incorporation documented by the comparatively low specific activity of isolated malate synthase is discussed in relation to the large pool of malate synthase already present in dry seeds.

Organs of crayfishes - mainly integument of Astacus leptodactylus - have been kept in an in vitro culture for several days. The medium consists of 2 parts of van Harreveld saline and one part of horse serum, supplemented with antibiotics for long term cultures. This medium is very similar to the Astacus hemolymph in its ionic content, the pH, the osmolarity, the protein concentration and the cholesterol content. The glucose concentration is somewhat higher and there are differences in the nitrogen excretory end products. Integument of Astacus is able to synthesize protein, RNA and DNA in vitro for several days. Ecdysone is converted to 20-OH-ecdysone by the integument under in vitro conditions.

The two major components of the female pheromone blend of Hedya nubiferana have been identified as (E, E)-8,10-dodecadienyl acetate and (Z)-8-dodecenyl acetate. Each compound acts on a specialist receptor type in olfactory hair sensilla of the male antenna. In field screening tests, combinations of the two compounds and dodecanyl acetate were highly attractive to H. nubiferana males. The (Z, E)-8,10 isomer attracted males of Hedya ochroleucana.

Unlike other related species wild flies of Drosophila subobscura require light for successful ma­ting. Two explanations for the influence of light on the reproductive behavior could be suggested: 1)Light increases sexual activity. 2)Light mediates the transmission of visual courtship elements. In order to decide this question the mating success of wild-type and mutant flies was tested at light of different wave-lengths. It turned out that mutant flies with reduced ommochrome compo­nent of the eye pigment were not able to copulate at wave-lengths above 570 nm whereas the other strains still copulated at wave lengths close to the limit of their spectral sensitivity. Since spectral sensitivity of the photoreceptors is assumed to be the same in all strains tested the difference in mating success must be ascribed to effects caused by the lack of pigment. Thus an investigation of the optomotor response was carried out. It revealed that mating success is clearly correlated with the ability to discriminate contrast. From this result it can be concluded that the exchange of visual signals and not merely the perception of light is essential for the courtship of Drosophila subobscura. Optical stimuli may be important at two different stages of mating behavior: at the begin­ning, when the male is activated by the sight of a female, and during the wing dance, where the movements of the partners are coordinated optically.

The effect of precocene II on development of the honey bee, Apis mellifera, was studied in vitro. One- to two-day-old worker larvae (body weight 0.5 - 1.0 mg) were removed from the colonies, reared on royal jelly-yeast extract, and after 24 h were topically applied with different amounts (5 - 75 μg/larva) of precocene II. Toxicity was observed only with precocene doses of 50 μg/larva and more. The larval weight-gains declined with the increase of doses. The acetone-treated control had better survival and weight-gain as compared to the no-treatment control. The larval and pu­pal periods in the treated larvae remained unchanged as compared to the controls. The possibility of precocene acting as an antifeedant is discussed.

The calculation of the photochemical yield of simple reactions in viscous media was discussed earlier in a rather formal way. In this paper the basic equation will be derived in a more convenient way and the numeric results of an application to photoisomerization are given. The main purpose is to demonstrate the possibility to handle even complicated reactions.

Phylogenetic Dendrograms, Molecular Evolution For the construction of a phylogenetic tree an algorithm is described. This, allows the correction of the original data and the proper selection, in each step of the process, of the nearest neighbours of a common ancestor.

The presence of thioredoxin was demonstrated in 20 strains of cyanobacteria as well as in one phototrophic bacterium Rhodopseudomonas sulfidophila and in Thiobacillus denitrificans. Thioredoxin activity was not found in Cyanophora paradoxa and in Porphyridium cruentum using the thioredoxin-dependent PAPS-sulfotransferase activity from Synechococcus 6301 as assay system.

The element concentration of the lichen species Alectoria fremontii and its substrate (bark of Pinus sihestris) were studied. It appeared that the content of all the investigated elements, except for vanadium, was higher in the lichen samples than that in the corresponding bark samples. Analysis-of-variance procedure has demonstrated that the concentration of N, P, S, Se, V, Hg and U in lichen samples appeared to change significantly in samples gathered from two different height-zones on the stems above ground level. However, this was not the case with the bark samples. The elements Se, V, Hg, U, Co and Mo determinations of the samples were performed by neutron activation methods.

5-hydroxymarmesin administered to leaves of Ficus carica and to cut ends of Ruta graveolens has been efficaciously and selectively converted into bergapten while no radioactivity was observed in the other isolated furocoumarins.

In electroantennographic studies on Tortrix viridana ma­les, (E)-11-tridecenyl acetate displayed the highest activity of all straight-chain alkenyl acetates. However, evidence obtained by gas chromatography coupled to an electroan­tennographic detector or a mass spectrometer indicated that the ubiquitous pheromone compound (Z)-11-tetrade- cenyl acetate is the main component in the T. viridana fe­male secretion. This compound and both (Z)- and (E)-11- tridecenyl acetate were found to be attractants for T. viridana males in the field. (Z)-9- and (E)-11-tetradecenyl acetate were not attractive and reduced male catches when added to either (Z)-11-tetradecenyl acetate or (E)-11-tridecenyl acetate. No evidence for synergistic effects was obtained.

The staining reaction of chromatin by aluminium -hematoxylin was investigated. Intense staining, which proved dependent on nucleic acid content, was achieved by using either the preformed lake, mordanting followed by hematoxylin, hematoxylin alone or the lake at high ionic strength. Extraction procedures removed aluminium ions from chromatin but the lake was retained. Chromatin fluorescence induced by ethidium bromide and acridine orange was abolished after staining with the lake. Intercalating-like forces are suggested for aluminium -hematoxylin binding to chromatin.

The formation is reported of platinum blues by 5′-CMP and by 5′-UMP.

Extraction of pollen of Nothofagus antarctica with acid hydrolysis yields kaempferol, quercetin, the rare flavonol sexangularetin, and naringenin. The tetrahydroxy-chalcone isosalipurpol is shown for the first time to occur in such high amount as free aglycone in mature pollen; it yields naringenin in usual extraction procedures. The bright yellow coloration of the pollen is due to the presence of isosalipurpol and sexangularetin.

The rate constants of the reactions between pulse radiolytically produced superoxide radicals and the Cu(II) chelate of diethyldithiocarbamate were determined at pH 7.0. It was found that diethyldithiocarbamate forms a copper complex, which has no dismutating activity. The removal of the protein bound copper in superoxide dismutase by diethyldithiocarbamate yields the same effect as coordination of the copper in the enzyme.

An alternative method for the integration of the differential equations in photokinetics is derived, having some advantages compared to another one previously published by the author. Furtherto this approach gives the chance to handle the problems of photoreactions caused by polychromatic irradiation.