Proteolytic activity in the genus ficus

The latices of only 13 of a total of 46 species of Ficus examined contained appreciable proteolytic activity. Therefore, high proteolytic activity in the latex is not a distinguishing feature of the genus. The latex of F. stenocarpa had the highest specific activity followed closely by the latices of F. carica and F. glabrata. Latices of 6 species of Ficus were examined by chromatography on CM-cellulose and compared with the results obtained for 9 varieties of F. carica. All of the latices were found to contain multiple proteolytic enzymes. Chromatographically, the multiple enzyme components of the several varieties of F. carica were more similar than those of the several species examined. The latices of 16 varieties of F. carica were all different as determined by free boundary electrophoresis although the specific proteolytic activity of the latices was reasonably constant.     

Comparative Study on Plant Latex Particles and Latex Coagulation in Ficus benjamina,Campanula glomerata and Three Euphorbia species

Among latex-producing plants, mainly the latex of Hevea brasiliensis has been studied in detail so far, while comprehensive comparative studies of latex coagulation mechanisms among the more than 20,000 latex-bearing plant species are lacking. In order to give new insights into the potential variety of coagulation mechanisms, the untreated natural latices of five latex-bearing plants from the families Euphorbiaceae, Moraceae and Campanulaceae were visualised using Cryo-SEM and their particle size compared using the laser diffraction method. Additionally, the laticifers of these plants species were examined in planta via Cryo-SEM. Similar latex particle sizes and shape were found in Ficus benjamina and Hevea brasiliensis. Hence, and due to other similarities, we hypothesize comparable, mainly chemical, coagulation mechanisms in these two species, whereas a physical coagulation mechanism is proposed for the latex of Euphorbia spp. The latter mechanism is based on the huge amount of densely packed particles that after evaporation of water build a large surface area, which accelerates the coagulation procedure.     

Lectins from latices of Euphorbia and Elaeophorbia species

Crude latex sera from 17 members of the genus Euphorbia and from Elaeophorbia drupifera (Euphorbiaceae) contained a wide range of agglutinating abilities. Homogeneous lectins were isolated from latices of Euphorbia coerulescens, E. hermentiana, E. lactea, E. lactea cristata, E. lathyris, E. trigona and Elaeophorbia drupifera. The M,s of the lectins ranged from 60 to 67 000, and the unit weights from 27 to 38 000. pI measurements showed that each latex contained from five to 13 isolectins. The amino acid compositions of the seven lectins were determined: those from E. hermentiana, E. lactea, E. lactea cristata, E. trigona and Elaeophorbia drupifera are related.     

Sterols and triterpenols in latex and cultured tissues of Euphorbia pulcherrima

The sterol and triterpenol constituents of Euphorbia pulcherrima latex and cultured callus tissues were examined by GLC and mass spectrometry. Latex extracts from different varieties contained sitosterol, β-amyrin, germanicol, cycloartenol, β-amyrin acetate, and germanicol acetate. Capillary GC profiles of these varieties indicated that the triterpene content was essentially identical for examined latices. Cultured tissues derived from petioles and stem internodes synthesized only sitosterol in significant quantities, although trace amounts of several sterols that occur in latex were also detected in cultured tissues. This study supports the interpretation that the pattern of triterpene synthesis in the laticifer of the normal plant is a highly controlled and stable phenomenon among varieties of this species.     

Phospholipid composition of the membrane of lutoids from Hevea brasiliensis latex

Intact lutoids were isolated from the latex of Hevea brasiliensis and purified on a sucrose density gradient. Lutoid membranes prepared by osmotic lysis are characterized by a high content of phosphatidic acid in which unsaturated and saturated fatty acids are present in equal proportions. Linolenic acid is absent. The results are discussed in relation to the biological role of lutoids in the latex vessels of Hevea brasiliensis.     

Organic Acids of Ditylenchus triformis and Turbatrix aceti

Pyruvic acid, lactic acid and several tricarboxylic acid cycle acids were extracted from Ditylenchus triformis and Turbatrix aceti and identified. Fumaric acid was predominant in both nematodes. Small amounts o f malic and α-ketoglutaric acids and intermediate quantities o f lactic, citric, succinic, and pyruvic acids occurred in D. triformis. In T. aceti citric, lactic, and α-ketoglutaric acids were less abundant than succinic, malic and pyruvic acids. Only traces of aconitic and oxalacetic acids occurred in both nematodes. All the organic acids detected accounted for only about one per cent of the dry weight of nematodes o f the two species.     

Phosphatidylglycerol and chilling sensitivity in plants

The hypothesis that molecular species of thylakoid phosphatidylglycerol containing two saturated fatty acids (disaturated phosphatidylglycerol) confer chilling sensitivity upon plants was tested by analyzing the fatty acid composition of phosphatidylglycerols isolated from leaves of a range of plants expected to have different sensitivities to chilling temperatures.

`Saturated' fatty acids (palmitate plus stearate plus hexadeca-trans-3-enoate) as a proportion of total phosphatidylglycerol fatty acids varied from 51 to 80 mole per cent in the plants analyzed but appeared to be rigidly fixed for a given plant species, being unaffected by leaf maturity or by environment.

Hexadeca-trans-3-enoate occurred only at the sn-2 position, whereas C-18 fatty acids occurred only at the sn-1 position of thylakoid phosphatidylglycerol. Therefore, the proportion of disaturated molecular species could be predicted accurately from the total fatty acids of phosphatidylglycerol.

Disaturated molecular species accounted for <25% of the total phosphatidylglycerol from leaves of chilling-resistant plants and for 50 to 60% of the phosphatidylglycerol in leaves from some of the most chilling-sensitive plants. However, not all chilling-sensitive plants contained high proportions of disaturated phosphatidylglycerol; solanaceous and other 16:3-plants and C₄ grasses may be important exceptions. Nonetheless, proportions of disaturated phosphatidylglycerol increased concomitantly with increasing chilling sensitivity of plants within a genus.

     

Characterization of papain-like isoenzymes from latex of Asclepias curassavica by molecular biology validated by proteomic approach

Latices from Asclepias spp are used in wound healing and the treatment of some digestive disorders. These pharmacological actions have been attributed to the presence of cysteine proteases in these milky latices. Asclepias curassavica (Asclepiadaceae), “scarlet milkweed” is a perennial subshrub native to South America. In the current paper we report a new approach directed at the selective biochemical and molecular characterization of asclepain cI (acI) and asclepain cII (acII), the enzymes responsible for the proteolytic activity of the scarlet milkweed latex. SDS-PAGE spots of both purified peptidases were digested with trypsin and Peptide Mass Fingerprints (PMFs) obtained showed no equivalent peptides. No identification was possible by MASCOT search due to the paucity of information concerning Asclepiadaceae latex cysteine proteinases available in databases. From total RNA extracted from latex samples, cDNA of both peptidases was obtained by RT-PCR using degenerate primers encoding Asclepiadaceae cysteine peptidase conserved domains. Theoretical PMFs of partial polypeptide sequences obtained by cloning (186 and 185 amino acids) were compared with empirical PMFs, confirming that the sequences of 186 and 185 amino acids correspond to acI and acII, respectively. N-terminal sequences of acI and acII, characterized by Edman sequencing, were overlapped with those coming from the cDNA to obtain the full-length sequence of both mature peptidases (212 and 211 residues respectively). Alignment and phylogenetic analysis confirmed that acI and acII belong to the subfamily C1A forming a new group of papain-like cysteine peptidases together with asclepain f from Asclepias fruticosa. We conclude that PMF could be adopted as an excellent tool to differentiate, in a fast and unequivocal way, peptidases with very similar physicochemical and functional properties, with advantages over other conventional methods (for instance enzyme kinetics) that are time consuming and afford less reliable results.     

A comparison of the metabolic fate of Fatty acids of different chain lengths in developing oilseeds

To determine if medium and long chain fatty acids can be appropriately metabolized by species that normally produce 16 and 18 carbon fatty acids, homogenates of developing Cuphea wrightii, Carthamus tinctorius, and Crambe abyssinica seeds were incubated with radiolabeled lauric, palmitic, oleic, and erucic acids. In all three species, acyl-CoA synthetase showed broad substrate specificity in synthesis of acyl-coenzyme A (CoA) from any of the fatty acids presented. In Carthamus, two- to fivefold less of the foreign FAs, lauric, and erucic acid was incorporated into acyl-CoAs than palmitic and oleic acid. Lauric and erucic acid also supported less glycerolipid synthesis in Carthamus than palmitic and oleic acid, but the rate of acyl-CoA synthesis did not control rate of glycerolipid synthesis. In all species examined, medium and long chain fatty acids were incorporated predominantly into triacylglycerols and were almost excluded from phospholipid synthesis, whereas palmitic and oleic acid were found predominantly in polar lipids. However, the rate of esterification of unusual fatty acids to triacylglycerol is slow in species that do not normally synthesize these acyl substrates.     

Long chain esters of Virola species

The esters of n-fatty acids and ω-hydroxy n-fatty acids of β-sitosterol, D-glucose and ferulic acid (trans and cis) as well as β-sitosterol, fatty acids and β-sitosteryl-β-D-glucoside were isolated from three Virola species and identified by optical data and chemical reactions. A novel series of acidic esters derived from C₂₂C₂₉ ω-hydroxy fatty acids and cis- and trans-ferulic acid is reported for the first time. These compounds also occurred as the corresponding diester 1-monoglycerides whereas the ω-hydroxy acids themselves were also present as the corresponding glucosyl esters.     

Assimilation and biosynthesis of lipids in Arctic Calanus species based on feeding experiments with a C labelled diatom

The dominant Arctic Ocean and North Atlantic copepods Calanus hyperboreus, Calanus glacialis, and Calanus finmarchicus were collected in the Greenland Sea and fed ¹³C labelled diatom Thalassiosira weissflogii to follow the transfer and assimilation of carbon, lipid, and individual fatty acids and alcohols. The diatom was grown with ¹³C for 3 to 5 days and fed then to the copepods. During the feeding period of 14 days, total carbon increased in the copepodite stages V of C. hyperboreus and C. finmarchicus, whereas carbon remained almost constant in C. glacialis females. However, total lipid increased in all species and stages. Highest lipid accumulation occurred in C. hyperboreus in which nearly all lipids were exchanged already after 11 days of feeding. In the other species lipid accumulation made up between 22% (C. finmarchicus) and 45% of total lipid (C. glacialis). The proportion of wax esters was high ranging from 76% of total lipid in C. glacialis to 92% in C. finmarchicus. The fatty acid composition of the alga was dominated by 16:1(n-7), 16:0, 20:5(n-3), and 22:6(n-3). The composition of the copepods was similar because of feeding already on diatoms in the field. In addition, the monounsaturated fatty acids and alcohols, 20:1(n-9) and 22:1(n-11), were major components of the copepod lipids. During the feeding period the highest ¹³C labelling was always found in the C₁₆ polyunsaturated fatty acids and in the 16:1(n-7) alcohol. Because these components occurred only in trace amounts in the copepods they totally originated from the diet explaining the high labelling. It is noteworthy that the 16:1(n-7) alcohol originated only from the corresponding dietary and not from the abundant internal fatty acid. The long-chain monounsaturated fatty acids and alcohols, 20:1(n-9) and 22:1(n-11), are not existent in phytoplankton and have to be produced de novo. They were less labelled in the smaller species but highly ¹³C enriched in C. hyperboreus. Although dietary fatty acids were generally retained by the copepods it seems that fatty acids or even lipids were selectively accumulated and turned over due to bodily requirements, and thus, essential polyunsaturated fatty acids were preferentially retained. During feeding mixing, accumulation, and exchange of internal and dietary fatty acids and alcohols occurred as well as utilisation of lipids from both sources for metabolic requirements. The differences in lipid assimilation fit to the different life strategies of the copepods.     

Phospholipid and acid composition of Nocardia and nocardoid bacteria as criteria of classification

Phospholipid and acid composition of 5 strains of ‘true’ Nocardia and 4 strains of nocardoid bacteria have been studied. A great homogeneity was found in all the Nocardia species: phospholipids consist of cardiolipin, phosphatidyl ethanolamine, phosphatidylinositol and phosphatidylinositol mannoside. Streptomyces (Nocardia) mediterranei did not contain phosphatidylinositol and Oerskovia (Nocardia) turbata had no phosphatidyl ethanolamine. The fatty acid composition of these phospholipids was determined and was found different in Nocardia and nocardoid species. Nocardia were rich in straight chain fatty acids and tuberculostearic acid while the phospholipids of nocardoid bacteria contained greater amounts of branched fatty acids. The fatty acids from acetone soluble lipids consisted of hydroxy and non-hydroxy compounds. Hydroxy acids were found in Nocardia which contained nocardic acids: high MW β-hydroxy α-branched acids and in S. mediterranei which contained β-hydroxy acids with 15–17 carbon atoms. Non-hydroxy acids were essentially palmitic and tuberculostearic acids in Nocardia species while S. mediterranei and O. turbata contained great amounts of iso acids from C₁₄ to C₁₇. Phospholipid and acid composition are discussed as criteria of taxonomic classification of Nocardia and related Actinomycetes.     

No Latex Starch Utilization in Euphorbia esula L

Utilization of leaf, stem, root, and latex starch was monitored in Euphorbia esula L. plants. Leaf, stem, and root starch decreased rapidly during a 52 day light starvation period while latex starch did not. Scanning electron and light microscope studies provided additional evidence that no changes in latex starch granules had occurred. Amylase activity (6.6 units per milligram protein) could be isolated from latex. However, latex starch granules were extremely resistant to enzymic hydrolysis by latex amylases, Bacillus subtilis α-amylase, and by amyloglucosidase from Aspergillus niger. Results indicate that latex starch grains do not function as utilizable carbohydrate in this species under these conditions.     

Fatty acids of rice coleoptiles in air and anoxia

The metabolism of lipids, like that of other components, was adversely and strongly affected when rice (Oryza sativa L.) coleoptiles were grown anaerobically. In aerobic coleoptiles, the amounts of total fatty acid, phospholipid, and total lipid per coleoptile increased by 2.5- to 3-fold between days three and seven, whereas under anoxia, the increases were all less than 60%. The total amount of lipid at day seven in anoxia was less than 30% of that in air. In air, the total fatty acid content at day three was 25 nanomoles per coleoptile and this increased to over 71 nanomoles per coleoptile at day seven. All acids except 18:0 showed substantial increases. In anoxia, the corresponding values for total fatty acids were 24 nanomoles and 27 nanomoles. The small increases were confined to the saturated fatty acids; no significant increase occurred in unsaturated fatty acids. A minor fatty acid constituent (16:1) increased from 0.09 to 1.99 nanomoles per coleoptile between days three and seven in air. This component was never observed in any fatty acid preparation from anaerobic coleoptiles. The major phospholipids under all conditions were phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, and phosphatidic acid. A small amount of unidentified phosphoester, not present on thin layer chromatography plates from aerobic coleoptiles, was seen in extracts of anaerobic coleoptiles. The fatty acyl substituents of each of the phospholipids were analyzed at days three and seven in coleoptiles grown aerobically and in anoxia. Each phospholipid had its own distinctive fatty acid composition which remained fairly constant under all treatments; 16:0 and 18:2 were the most abundant fatty acids in every phospholipid class. In air, the percentages of total fatty acids that were in the phospholipids were 86% on day three and 87% on day seven. In anoxia, the values at the corresponding ages were 47 and 57%. Since no net synthesis of unsaturated fatty acids occurred in anaerobic conditions, the small increase in total unsaturated acids in the phospholipids between days three and seven must have occurred at the expense of fatty acids preexisting in the neutral lipid. No unusual pathways of biosynthesis or unusual precursors are required to explain the presence of unsaturated fatty acids in the rice coleoptile. The present study and results of experiments where coleoptiles were fed [¹⁴C]acetate (BB Vartapetian et al. 1978 Plant Sci Lett 13:321-328) clearly show that unsaturated fatty acid synthesis in rice coleoptiles requires O₂, as it does in other plants.     

Distribution and chemotaxonomic significance of acetylenic fatty acids in mosses of the dicranales

Thirty-eight moss species from four families of the order Dicranales were analysed for the fatty acid composition of their acyl lipids. In the Ditrichaceae and the Dicranaceae numerous species were found to contain acetylenic fatty acids in their triglycerides, 9,12,15-Octadecatrien-6-ynoic acid was the major component, often accounting for more than 80 mol%, whereas 9,12-octadecadien-6-ynoic acid was found in small amounts of less than 5 mol%. In some genera, all the species examined contained acetylenic fatty acids, e.g.Dicranella andDicranum, whereas in the genusCampylopus all five species tested were free of acetylenic compounds. Two genera, Ditrichum andDicranoweisia, were found to have a non-homogeous distribution of acetylenic fatty acids. The chemotaxonomic significance of the fatty acid composition in relation to morphological characters is discussed.     

Thrombin-like serine protease,antiquorin from Euphorbia antiquorum latex induces platelet aggregation via PAR1-Akt/p38 signaling axis

Plant latex proteases (PLPs) are pharmacologically essential and are integral components of traditional medicine in the management of bleeding wounds. PLPs are known to promote blood coagulation and stop bleeding by interfering at various stages of hemostasis. There are a handful of scientific reports on thrombin-like enzymes characterized from plant latices. However, the role of plant latex thrombin-like enzymes in platelet aggregation is not well known. In the present study, we attempted to purify and characterize thrombin-like protease responsible for platelet aggregation. Among tested plant latices, Euphorbia genus latex protease fractions (LPFs) induced platelet aggregation. In Euphorbia genus, E. antiquorum LPF (EaLPF) strongly induced platelet aggregation and attenuated bleeding in mice. The purified thrombin-like serine protease, antiquorin (Aqn) is a glycoprotein with platelet aggregating activities that interfere in intrinsic and common pathways of blood coagulation cascade and alleviates bleeding and enhanced excision wound healing in mice. In continuation, the pharmacological inhibitor of PAR1 inhibited Aqn-induced phosphorylation of cPLA₂, Akt, and P38 in human platelets. Moreover, Aqn-induced platelet aggregation was inhibited by pharmacological inhibitors of PAR1, PI3K, and P38. These data indicate that PAR1-Akt/P38 signaling pathways are involved in Aqn-induced platelet aggregation. The findings of the present study may open up a new avenue for exploiting Aqn in the treatment of bleeding wounds.     

Caffeic acid ester derivatives and flavonoids of genus Arnaldoa (Asteraceae,Barnadesioideae)

The phytochemical composition of Arnaldoa species is barely known. In this work, the occurrence of caffeic acid ester derivatives and flavonoids in A. argentea, A. macbrideana and A. weberbaueri was established by liquid chromatography associated to high-resolution mass spectrometry analyses and comparison with data from isolated compounds. The distribution of chlorogenic acids in the genus Arnaldoa is herein described for the first time. The metabolite profile of Arnaldoa species was compared to that of Tithonia diversifolia, a known and rich source of chlorogenic acids and sesquiterpene lactones. In addition to the mono- and dicaffeoyl quinic acids present in T. diversifolia, Arnaldoa species exhibited the mono- and dicaffeoyl tartaric acids. Furthermore, mass features correspondent to that of sesquiterpene lactones present in T. diversifolia were not observed in Arnaldoa species. The chemotaxonomic implications of caffeic acid ester derivatives and flavonoid glycosides, as well as the potential absence of sesquiterpene lactones in the genus Arnaldoa and subfamily Barnadesioideae are discussed.     

Fatty acids of some cornaceae,hydrangeaceae, aquifoliaceae,hamamelidaceae and styracaceae

Seed, kernel or fruit oils of the Cornaceae (nine species). Hydrangea, Hamamelis, Ilex (Aquifoliaceae) and the Styracaceae (two species) were analysed for fatty acid composition. Special attention was paid to the occurrence of petroselinic acid (18: 1Δ6c). In the species investigated. C₁₈ acids were always present in greater quantities than C₁₆ fatty acids; C₂₀ and C₂₂ acids were only minor components. The Cornaceae show differing fatty acid patterns which correlate well with anatomical, morphological and other chemical data. In Cornus, Curtisia, Mastixia and Corokia linoleic acid predominates, whereas linoleic and linolenic acid form the major components in Davidia and Nyssa. 18 : 1Δ6c, an aralioid type, occurs in large amounts in Aucuba and Griselinia. Hamamelis, Hydrangea and Ilex show a common fatty acid pattern with linoleic acid as the dominant component in all cases. Classification currently based on morphological and anatomical differences between the two species of Styracaceae which were investigated here should include their different fatty acid compositions: in Halesia linoleic acid predominates over oleic acid, whereas in Styrax equal amounts of these two acids are found.     

Distribution and biosynthesis of theanine in Theaceae plants

The theanine content of the leaves of 27 species or varieties of Theaceae plants was investigated. Theanine was present in 21 species or varieties, but in much lower amounts (<0.2 μmol/g fresh weight) than the quantity detected in Camellia sinensis var. sinensis. The major free amino acids in leaves of four species belonging to the genera Schima and Eurya, were glutamic acid, aspartic acid, glutamine, asparagine, alanine and proline and content of these amino acids is similar to or higher than theanine. Accumulation of free amino acids in these plants was generally lower than in C. sinensis var. sinensis. The biosynthetic activity of theanine, assessed by the incorporation of radioactivity from [¹⁴C]ethylamine, was detected in seedlings of two species of Schima. The theanine biosynthetic activity in roots was higher than that of leaves.