Volume 45, Issue 7-8

Ribulosc bisphosphate carboxylase/oxygenase was purified to apparent homogeneity from the carboxysomes of Prochlorothrix hollandica.The MW of the native enzyme was estimated to be 560,000 Dalton, comprising large subunits (LSU) of 57,000 Dalton and small subunits (SSU) of 13,000, probably in an 8LSU8SSU quaternary structure. Enzyme activity was maximal at pH 8.0 at 30°C. The requirement of activity for Mg 2+ could not be replaced by Mn 2+ , Co 2+ , Ca 2+ or Cu 2+ .Amino acid N-terminal sequence analysis of the LSU showed a high degree of conservation when compared to cyanobacterial and chloroplast LSU sequences but was too short to allow a reliable phylogenetic assignment of P. hollandica.

In the present paper we demonstrate that the conformational state of the Afunctional enzyme ribulose-1,5-bisphosphate carboxylase oxygenase is different in the tobacco mulanl Susu when compared to the wild type tobacco or spinach. The conformational state of the tobacco mu- tant enzyme is characterized by the presence of a higher number of antigenic determinants ac- cessible to antibody binding. This seems to be correlated to a higher oxygenase activity in the mutant. The Afunctional enzyme ribulose-1,5-bisphosphate carboxylase oxygenase of the wild type tobacco Nicotiana tabacum var. John William’s Broadleaf, of the tobacco mutant Su.su and of spinach (Spinacia oleracea) was characterized by comparative immunological methods. Although the enzyme of the tobacco mutant appears identical to the enzyme of the wild type, when analyzed in immunodiffusion tests and immuno electrophoretical analyses, it exhibits a higher oxygenase activity. On the other hand the spinach enzyme exhibits only par- tial serological identity to the two tobacco enzymes. For the comparative studies pure IgG-fractions were prepared from the respective antisera. RuBP-carboxylasc oxygenase was used as a 70% purified enzyme preparation. Determination of the antibody binding capacity showed that the enzymes bind from the homologous antisera the highest amount of antibodies, which means that the antisera reflect the complementary picture of the enzyme structure. The enzyme molecules of N. tabacum var. JWB and of spinach bind 9 antibody molecules each. I lowevcr, the binding capacity of the tobacco mutant enzyme exhibiting the higher oxygenase activity is 30% higher. Measurement of the oxygenase function under the influence of the homologous as well as of the non-homologous antisera has led to the result that the oxygenase activity of all enzymes is inhibited. However, it is the degree of inhibition which differs. The antiserum to the mutant enzyme causes with the spinach as well as with the JWB-enzyme a higher degree of inhibition than that produced by the homologous antiserum. Therefore, a correlation between inhibitory effect brought about by this antiserum and the amount of antibodies bound does not exist. Whereas the enzyme of the tobacco wild type binds 20% less antibodies out of this antiserum its oxygenase activity is 60% more inhibited and the function of the spinach enzyme is 20% stronger inhibited although binding of antibodies from the antiserum to the tobacco enzyme is 50% lower. These observations permit the conclusion that the antiserum towards the mutant enzyme contains more antibodies with a higher binding affinity towards reactive regions of the oxy- genase function. This in turn means that the structure of this enzyme or its conformation must be different in comparison to the wild type enzyme.

The molar ratio of RuBP carboxylase/oxygenase to the CF 1 complex was determined in the wild type N. tabacum var. JWB and in various N. tabacum mutants, which differ with respect to their chloroplast structure and their photosynthetic and photorcspiratory activity. It appears that the ratio RuBP carboxylase oxygenase, CF 1 is not constant in the different mutants, and apparently depends on the chloroplast structure and the photosynthetic capacity. In the green phenotypes of N. tabacum var. Consolation, var. NC 95 and var. Xanthi. whose lamellar system consists of a balanced ratio of grana and intcrgrana regions the ratio is 3-4 RuBP car- boxylase/oxygenase molecules per CF 1 complex. In chloroplasts of the yellow-green mutant Su/su, and the yellow mutant of N. tabacum var. Consolation, whose lamellar system consists of extended intergrana regions and low stacked grana the RuBP carboxylase oxygcnasc/CF 1 ratio is reduced to about one half. The aurea mutant A. tabacum Susu var. aurea and the yel- low-green leaf patches of variegated tabacum var. Xanthi arc characterized by the fact that one molecule RuBP carboxylase oxygenase correlates to two CF 1 complexes. Also in the two N. tabacum mutants Su/su and Consolation green, that exhibit a 30% higher photorespiration these molar ratios depend on the chloroplast structure. The determination of the maximal binding of antibodies out of homologous and non-homo- logous antisera onto RuBP carboxylase oxygenase of the N. tabacum mutant Consolation showed, that the enzyme of the green mutant, which exhibits a higher oxygenase activity, has in comparison to the yellow-green and yellow phenotype of this mutant series and also in comparison to the wild type a 30 per cent higher antibody binding capacity. These differences in antibody binding arc shown in both the region of enzyme antibody equivalence and that of antibody excess. With the methods of enzyme-antibody precipitation in agarose gels these differences of enzymes, exhibiting higher or lower oxygenase activities, cannot be detected. The native enzymes and the large subunits of the enzyme of the three Consolation mutants yield in these test reactions with the enzyme of the wild-type fusing precipitation bands. Treatment with the chemical agent hydroxylamine. as well as heat treatment at 50 °C alters the enzyme conformation to such an extent that the antibody binding capacity is increased by 70%. The difference in the higher antibody binding capacity of the enzyme of the green mutant of N. tabacum var. Consolation is maintained also after these chemical modifications.

Mass spectromctric analysis reveals that oxygen evolution measured as the consequence of short saturating light flashes in thylakoid preparations of the filamentous cyanobacterium Oscillatoria chalybea consists of two portions, one coming from photosynthetic water splitting and one coming from H 2 O 2 decomposition. This H 2 O 2 decomposition is photosystem II-mediated and it is the S-state system which oxidizes H 2 O 2 to give protons and oxygen. Water is neither intermediate nor seems it to be the origin of the reaction. At the high oxygen partial pressure of normal air H 2 O 2 production and its decomposition exceeds manyfold the H 2 O splitting reaction. H 2 O 2 production seems to come from photosystem II but is not necessarily produced on the acceptor side of photosystem II in the sense of a Mehler type reaction. From the reaction rate and the observed labeling density, it is inferred that production and decomposition must take place within the same reaction site which might be for both, the production and decomposition, the S-state system. In this sense. H 2 O 2 might be the product of the S-state system and seems somehow associated with S 2 or S 3 . Thus, if oxygen evolution is measured as the consequence of short saturating light flashes in an ambient atmosphere of 21% oxygen, mass spectrometry reveals a flash pattern which bears the oxygen label of the ambient atmosphere and which has not much in common with an usual Kok sequence. Such a pattern might start in the first three flashes more or less as a Kok pattern would, but is then in the pattern portion usually characteristic for steady-state oxygen evolution characterized by a periodicity of two indicating that H 2 O 2 decomposition requires only two light quanta. At high oxygen partial pressure (e.g. in 21% , 16 O 2 ) both reaction portions can be quantitatively deter- mined by labeling the assay with H 2 18 O and measuring the evolved ( 16 O:: 18 O)/ 18 O 2 ratio which is representative for water splitting. The measured evolution of 16 O 2 (mass 32) represents H 2 O 2 decomposition, if the 16 O 2 portion calculated from the measured mass 34/36 ratio is subtracted. At low oxygen partial pressure the H 2 O 2 forming and decomposing reaction is largely sup- pressed and oxygen evolution from water-splitting prevails. As a hypothesis, H 2 O 2 production and its decomposition might be a defective performance of photosystem II at high ambient oxygen partial pressure in these cyanobacteria, perhaps due to the principal absence of two of the extrinsic peptides from photosystem II.

Thylakoid membranes from spinach were irradiated with UV light of 254 nm. Photosynthetic electron flow driven by photosystem II, but not by photosystem I is fully inactivated in about 2-5 min. Inactivation of electron flow is prevented by inhibitors of the Q B site of both the DCMU and of the phenol type. UV light inactivates electron How both under anaerobic and aerobic conditions. This is in contrast to white light where fast inactivation occurs only under anaerobic conditions and where only inhibitors of the DCMU-type protect. Inactivation of electron flow by UV light is followed on a slower time scale by a specific degradation of thylakoid membrane proteins. As shown by immunoblotting the D-1 protein and to a smaller extent also the D-2 protein subunit - that together form the reaction center of photosystem II - are de- graded during UV light irradiation. The disappearance of these proteins occurs only under aerobic conditions. Both types of QB site inhibitors prevent the degradation of the two plasto-quinone-binding proteins. A degradation product of the D-l protein is observed at about 8 kDa size. The results are discussed in their relevance to rapid turnover and photoinhibition in vivo and to the topology of the quinone-binding site in the D-1 and D-2 protein.

Evidence is presented to support the notion that the 16 kDa thylakoid polypeptide, called CF 0 II, is an essential subunit of the photosynthetic ATP-synthase complex CF 0 CF 1 : It is co-isolated with the other subunits of CF 0 CF 1 in preparations either using octylgluco- side/cholate or Triton X-100. It is co-precipitated by antibodies together with the other CF 0 CF 1 subunits. It is immunochemically not related to thylakoid polypeptides of higher molecular weight nor to some thylakoid polypeptides with similar apparent molecular weight be- tween 16 and 18 kDa: CF 1 ɛ, CF 0 I, subunit IV of the b 6 f complex, the 16.5 kDa peripheral poly- peptide of the oxygen evolving complex of PS II, and the intrinsic ferredoxin NADP reductase binding protein. The N-terminal amino acid sequences of CF 0 II and the reductase binding protein is determined by Edman degradation and compared: The two sequences arc different and not identical to other characterized thylakoid polypeptides. Monospecific antibodies against CF 0 II inhibit rebinding of CF 1 to EDTA treated thylakoid membranes, H + efflux from EDTA treated membranes and cyclic photophosphorylation. Thus the additional polypeptide CF 0 II qualifies for a functional subunit of the photosynthetic ATP-synthase.

The de novo synthesis of tryptophan decarboxylase (TDC) (EC 4.1.1.27) in cotyledons of Juglans regia L. was accelerated at an earlier stage of development by harvesting immature fruits. After a lag phase of 6 h TDC activity became detectable in isolated cotyledons and reached values of about 5 nkat · g FW -1 following a 24 h incubation in double-distilled water. The TDC synthesis was suppressed to about 20% by supplying the incubation medium with 2 to 6% sucrose. Phytohormones were also involved in the regulation of TDC synthesis. A highly sensitive reaction was observed with a 50% suppression resulting from an external supply of 1 x 10 -8 M gibberellic acid (GA 3 ). Abscisic acid (ABA) was much less effective, reaching a similar level of suppression only at an unphysiologically high concentration of about 6 x 10 -5 M . ABA, however, became one order of magnitude more effective when supplied together with sucrose. In contrast to GA 3 and ABA, an exogenous supply of indole-3-acetic acid (IAA) stimulated TDC synthesis significantly at a concentration of 1 x 10 -7 M . From these in vitro studies and earlier measurements of internal ABA concentrations as well as incorporation of [ 3 H]tryptophan into IAA. we hypothesize a regulatory effect of assimilate supply and phyto- hormones on TDC biosynthesis in developing embryos of walnut (Juglans regia L.).

Arsenate absorbed by zooxanthcllac in Tridacna species is converted to water-solubie arsen- ical products which accumulate in the kidney with concentrations up to 2%. Kinetic uptake experiments with radioarsenatc revealed rapid labeling in the algae and in the membrane lipids of the gills. Since the arsenic content of the gills is low. it is concluded that turnover is rapid and that the gills are the site of arsenic depuration in these clams. The amphipathic lipid nature of the gill arsenicals suggests membrane lipid mediation of the process.

An acid-labile antigenic polysaccharide has been isolated from both cell walls and culture media of Propionibacterium acnes using a new chemical degradation procedure which liberates protein-bound or associated carbohydrate. Lyophilized cells and culture media were treated with a suspension of mercuric oxide in a solution of alkaline mercuric cyanide for several hours at room temperature liberating water-soluble polysaccharide material. The antigenic polysac- charide was freed of reaction products by alcohol extraction and purified by anion exchange chromatography and gel filtration, resulting in three distinct fractions of acidic polysaccha- rides of apparent molecular weights between 15 - 50 kDa. Sugar analysis showed the polysac- charides to contain fucose, galactose, glucose, mannose, galactosamine. glucosamine, and 2,3- diamino-2.3-dideoxy-D-glucuronic acid. The three fractions also contained amino acids, predominantly glutamic acid, alanine, and glycine, known to be components of P. acnes cell wall peptidoglycan. All three molecular weight fractions reacted with rabbit antisera raised against whole P. acnes cells, with the highest titer for both cell and media-derived polysaccharide material consistently in the high molecular weight fraction. This procedure was also capable of releasing antigenic polysaccharide from tissues of rats administered P. acnes cells or radio- labeled cell wall fragments.

The leaf cpicuticular waxes of beech trees (Fagus sylvatica L.) were analyzed continuously all over one vegetation period with preparations every week from April 24 to November 15. The folded leaves in buds contained hydrocarbons, wax esters, benzyl acyl esters, alcohols and fatty acids from the beginning, but not aldehydes. Aldehydes were identified only after 10 days of leaf unfolding. The biosynthesis of wax lipids was rapid in the first three to five weeks till May 30. During this time the wax lipids were doubled quantitatively and the chain length spccifity has also changed in all wax lipid classes. From June to October the composition of the wax lipid classes and also the chain length specifity remained constant with the exception of fatty acids. The biosynthesis of wax lipids was found to be very dynamic in the first five weeks and correlated with the leaf development and growth.

The leaves of three deciduous broadleaf trees namely Quercus rohur L. (oak), Acer pseudo- platanus L. (maple) and Juglans regia L. (walnut) have different wax surface structures with different chemical compositions. On both the upper and lower side of the oak leaf, crystalloid platelets with sharp fringed edges were observed. Maple and walnut leaf surfaces showed quite different crystalloid arrangements on the upper and the lower side of the leaves. On the lower side of the maple leaf crystalloid platelets in form of lumps were found, whereas the upper side showed no crystalloids. Walnut leaves exhibited dense platelets with rounded edges on the upper side but not on the lower side.

In addition to the previous isolated and sequenced polypeptides from green photosynthetic sulfur bacteria, which are presumably involved in binding BChl c and e, an analogous poly- peptide has been purified from the BChl d-containing bacterium Chlorobium vibrioforme f. thiosulfatophilum. The primary structure of this 6.15 kDa polypeptide was determined. It shows an extremely high homology (98.3%) to the corresponding polypeptide from Pelodictyon luteolum, indicative of an important functional role.

Chlorosomcs containing BChl a 790 have been isolated from Chloroflexus aurantiacus on sucrose density gradients using the detergents Miranol. Deriphat. N.N-dimethyldodecyl- aminc-N-oxidc, and dodecyl-p-D-rnaltoside. All freshly prepared samples cither lack the poly- peptide of approximately 5 kDa. which appears identical with the 5.6-kDa protein previously assigned the role of BChl c-binding [R. G. Feick and R. C. Fuller. Biochemistry 23, 3693- 3700 (1984)]. or they contain only a minor amount thereof. This polypeptide accumulates in the chlorosomcs in vitro at room temperature within 24 h after isolation. The reaction cannot be prevented simply by addition of the protease inhibitors benzamidinc. F.-caproic ac|d. and phenylmethylsulfonyl fluoride. However, upon denaturation, as required lor gel electrophore- sis, of the freshly isolated chlorosome sample the formation of the 5-kDa polypeptide is inhibit- ed. We conclude that this species, viz. 5.6-kDa protein, is a degradation product of another - as yet unidentified - protein present in the chlorosome preparations. Despite the pronounced proteolytic activity which affords the 5-kDa fragment, the native absorption and fluorescence properties of BChl c and BChl a arc essentially not changed in these chlorosome preparations.

An earlier study of phytoalexin formation in the genus Trifolium has now been extended to include a further 61 species and subspecies. Using the drop-diffusate method, isoflavonoid phytoalexins were isolated from the fungus-inoculated leaflets of 55 accessions, whilst four others produced the stilbene derivative resveratrol. Phytoalexins could not be obtained from the leaflets of two species, T. billardieri and T. grandiflorum. The pterocarpan medicarpin was the most commonly encountered phytoalexin, occurring alone or in various combinations with the known Trifolium isofjavonoids maackiain (pterocarpan), vestitol, isovestitol, sativan, isosativan and arvensan (all isoflavans). Two additional pterocarpans, 4-methoxymedicarpin from T. cherleri and T. pallescens, and 4-hydroxyhomopterocarpin also from T. pallescens, were recognized for the first time as Trifolium phytoalexins. Re-examination of T. aureum re- vealed that this species produced resveratrol as a phytoalexin and not the isoflavan vestitol as previously described.

Volatile compounds which are released from fresh leaves of Thuja occidentalis inhibited germination of seeds of Amaranthus caudatus and Lepidium sativum. The volatile compounds were obtained by a vacuum method applied to the leaves, by direct analysis of the content of secretory organs and by solvent extraction of leaves. The bioactive compounds proved to be monoterpenes. The highest bioactivity were found for alcoholic compounds followed by ketones, esters and finally hydrocarbons. Non-volatile germination inhibitors which were ex- tracted with hot water were abscisic acid (3-4 µg/g fresh weight of leaves), and two oxidation products of thujone, 2-[2′-acetyl-l′-isopropyl]cyclopropylacetic acid (“Thujaketosaure”) and 3-isopropyl-5-oxohex-2-enoic acid. These compounds could also be prepared from thujone. The relationship of these compounds with possible allelopathic effects of Thuja occidentalis is discussed.

The structure of fulvoferruginin (1), a carotane derivative from cultures of Marasmius fulvoferrugineus, has been established by spectroscopic investigations and an X -ray structure analysis. 1 exhibits antibacterial, antifungal. and cytotoxic activities.

Hormaomycin is a novel signal metabolite from Streptomyces griseoflavus W-384 with aerial mycelium-inducing activity. The compound has been identified as an unusual peptide lactone. Hormaomycin displays three biological activities: First, it initiates the development of aerial mycelia in some Streptomyces strains. The mechanism responsible for this activity is unknown. Secondly, hormaomycin is effective in stimulating antibiotic production in different Streptomyces species. Thus, it is possible to get overproduction of a variety of antibiotics by the use of hormaomycin in fermentation processes. Thirdly, it inhibits the growth of some bacteria. The sensitive bacteria are restricted to coryneform taxa such as Arthrobacter and Corynebacterium which are closely related to Streptomyces.

The herbicide Comm and (2-(2-chlorophenyl)methyl-4,4-dimethyl-3-isoxazolidinone) does not affect the in vitro activities of the plastid enzymes catalyzing the steps leading from isopen­ tenyl diphosphate to geranylgeranyl diphosphate and phytoene, i.e. the isopentenyl diphos­ phate isomerase, prenyl transferase and phytoene synthase. The extractable activities of these enzymes in herbicide-treated seedlings are also not affected. Nevertheless, the synthesis of chlorophylls and carotenoids in treated seedlings is severely inhibited in vivo. The mode of action of Comm and remains still unknown.

The effect of physical loading on period and amplitude of the ultradian oscillating leaflets of Codariocalyx motorius (= Desmodium gyrans) and the circadian oscillating leaves of Oxalis regnellii was investigated. In Codariocalyx the leaflets were loaded with pieces of copper thread which were clamped to the leaflet. Weights of the loads varied from 3 to 12 mg, and a typical leaflet is 1.5 mg. In about 80% of the cases we recorded an increase of the period length due to the loading in the order of 10% (the period length is typically 3-4 min). The amplitude was lowered in all the cases, the magnitude depending on the size of the weight used. In most of the cases, when not too heavily loaded, both amplitude and period returned to (or close to) the previous value when the leaflets were unloaded. In Oxalis the leaves were loaded with metal clips fixed to the leaflets at the midrib position. All three leaflets on a stalk were loaded. The clips used weighed 390 ± 0.4. 640 ± 6 and 810 ± 4 mg respectively, and a typical leaflet is 91 ± 4 mg. For the heaviest weights at least, this resulted in a lowering of the amplitude, but the oscillations continued, and we could not observe any effect on the period of the rhythmic movements.

Gel electrophoresis of the white flocculcnt phcromonc disseminating secretions produced by males of the three dung beetle species, Kheper lamarcki, K. nigroaeneus and K. subaeneus, revealed that three different proteins with molecular masses of ca. 15 kDa are the major constitu- ents of these secretions. The molecular mass of these components in the secretions of K. lamarcki and K. nigroaeneus was determined more accurately by 252 Cf plasma desorption mass spectrometry to be 15451 ± 10 and 15477 ± 10 Da respectively. The N-terminal amino acids in the major proteinaceous component of the secretions revealed similarities as well as differences in the primary structures of the proteins secreted by the three species. The amino acid composition of the secretions of the three species is closely related. Due to the presence of large amounts of aspartic and glutamic acid, and small amounts of the basic amino acids, the pro- teinaceous component of the carrier material is expected to have a low isoelectric point which, together with the presence of large amounts of the hydrophobic amino acids, may impart properties that are to be expected for a carrier material which is used for the dissemination of inter alia long-chain fatty acids and their esters. Exposure of bovine pancreas trypsin, bovine albumin and the carrier protein of K. lamarcki to the vapour of 2,6-dimcthyl-5-hcptcnoic acid, the major volatile constituent with electro- antennogram activity in the secretion of this species, followed by quantitative determination of the acid adsorbed on these proteins, showed that albumin and the carrier protein have an approximately equal affinity for the acid, whereas trypsin retained only about one third of the amount of the acid adsorbed on the other two proteins. It was concluded that albumin should be a suitable substitute for the carrier protein in field tests with synthetic constituents of the abdominal secretion of these insects.

Glycosaminoglycans prepared from extracts of non-luleal mouse ovaries (JCL-ICR strain) were assayed for neovascularization by implanting Elvax films, impregnated with test samples, on the lateral wall of the sheath of m. rectus abdominis in adult mice of the same strain. Neovascularization occurred in a dose-dependent manner. When purified by chromatography on Dowcx 1-x 2 and DEAE Sephadex columns, fractions eluted with 0.5 M NaCl showed strong ncovascularizing activity. On further purification by high performance liquid chromatography using TSK gel DEAE 2SW column, the fraction with a retention time nearly coincident with that of hyaluronic acid possessed high ncovascularizing activity. The activity of this fraction was markedly reduced when treated with streptococcal hyaluronidase. The present results suggest that glycosaminoglycans, especially a hyaluronic acid-like substance, are involved in ovarian neovascularization.

The processing of dietary pyrrolizidine alkaloids by larvae and adults of the arctiid moth Creatonotos transiens was studied in time-course experiments: In larvae, pyrrolizidine alkaloid uptake is quickly followed by the transformation of the alkaloids into their N-oxides. Further- more, if 7 S-heliotrine is applied, a stereochemical inversion of the hydroxyl group at C 7 to 7 R-heliotrine can be observed within 48 h of feeding. The rate of this biotransformation is substantially higher in males which use the 7 R-form later as a precursor for the biosynthesis of 7 R-hydroxydanaidal, a pheromone. The resorbed pyrrolizidine alkaloids are deposited in the integument within 48 h, where they remain stored during the larval, pupal and partly also the imaginal stages. Virtually no alkaloids are lost during ecdysis. Some pyrrolizidine alkaloids can be recovered from the meconium which is released at eclosion by the imagines especially when disturbed. In the adults pyrrolizidine alkaloids are processed in different ways by the two sexes: In females, about 50-80% of total alkaloids are transferred from the integument to the ovaries and the eggs within 2 - 3 days after eclosion. If females mate with alkaloid-rich males they additionally receive with the spermatophore up to 290 jig pyrrolizidine alkaloid, which are further translocated to the eggs. A biparental endowment of eggs with acquired defence alkaloids is thus achieved. In males, 30-50% of pyrrolizidine alkaloids remain in the integu- ment; about 10 - 30% are transferred to the scent organ, the corema, where they are converted into 7 R-hydroxydanaidal. Another part (about 40%) is passed to the spermatophore. In the laboratory experiments, the sizes of the coremata and their respective 7 R-hydroxydanaidal contents are strongly dependent on the availability of dietary pyrrolizidine alkaloids during L6 and especially L7 stages. In the L7 stage even short-term feeding (4-6 h) on Senecio jaco- haea is sufficient to induce large coremata.

A synthetic mixture containing 1-indanone, 2-pentanone, 2-methyl-3-pentanone, 3-mcthyl- 2-pentanone, 2-methylcyclopentanone. 1-hydroxy-propanone. acetophenone, benzaldehyde. n-nonanal, n-decanal, nerolidol, eugenol, thymol, carvacrol and phythol deters oviposition of the Egyptian cotton leaf worm, Spodoptera littoralis (Boisd.). All compounds were identified from larval frass of S. littoralis.

Polymyxin B produces dose dependent changes in the surface topography of pathogenic Vibrio cholerae cells. The susceptibilities of various vibrio strains to PB are also studied through analytical techniques. Statistical analysis shows significant differences among the four vibrios with regard to their sensitivities to PB, the classical strains being the most sensitive. Treating the classical strain with subinhibitory concentration of PB. we observed with both SEM and TEM that the normal smooth surface of the cell envelope develops some protruded structures (blebs and crenations). Further the TEM study of the ultrathin sections reveal that the rod like projections are formed by protrusions of the outer-membrane of the cell wall.

We present a method to determine concentrations of glycine between 1 and 3 mM in the simultaneous presence of 25-100 mM glutamate, which is a modification of the procedure originally described by Klein and Linscr. Z. Physiol. Chem. 205,251 (1932). Glycine and glutamate react with 150 mM w-phthaldialdehyde, glycine is quantitatively con- verted into a colored o-phthaldialdehyde-glycine-glutamate complex. By recording the ab- sorbance of the complex at its maximum peak (around 540 nm). at 600 nm and 480 nm and applying a correction formula is possible to obtain a very good linear correlation when plot- ting the values of corrected absorbance versus the concentration of glycine. From these plots an extinction coefficient of 7.0 x 10 2 cm -1 m -1 was calculated for the complex. The method is highly reproducible and sensitive and solved the problem of glutamate interference when esti- mating low concentrations of glycine in mixture containing 10 to 50 times concentrations of the former aminoacid.

The title compound. 9-(1,3-dihydroxy-2-propoxymethyl)adenine (DHP-Ade). an analogue of the antiviral acyclonucleoside 9-(1,3-dihydroxy-2-propoxymethyl)guanine (DHPG), crystallizes in the monoclinic space group P2 1 . with unit cell dimensions of a = 10.848(4), b = 8.765(3), c = 11.432(4) Å. β = 102.14(3)° . with two independent molecules in the asymmetric unit. The crystal structure of DHP-Ade was determined and compared with that for DHPG. The solution conformations of both acyclonucleosides were also determined with the aid of 1 H and , 13 C NMR spectroscopy. In the solid state the acyclic chain may adopt a “folded” form, i.e. gauche about the C(1′)-O(1′) bond (as in DHP-Ade), or an “extended” form (as in DHPG), results which corre- spond to the rotations about this bond in solution. A general discussion is presented of the conformations of the acyclic chains of various acyclonucleosides, from the antiviral 9-(2-hydroxyethoxymethyl)guanine (Acyclovir, ACV) through to 2′,3′-seco-nucleosides, both in the solid state and in solution, and the relevance of these to biological activities.

The exudate dry matter of the Cicer arietinum geno­ type ICC 506 is composed of three main organic acids, malate (61.2%), oxalate (28.6%), and glucose-6 -phosphate (5.5%). Minor com ponents are citrate (2.5%), succinate (1.2%), m alonate (0.6%), oxalacetate (0 .2 %), and fumarate (0 .2 %).

Volatile compounds of the pheromone bouquet of Nereis virens have been isolated and identified from the coelomic fluid of ripe sub-heteronereids. One of the minor compounds is the sex pheromone of Platynereis dumerilii, 5-methyl-3-heptanone.