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Assessment of airborne heavy metal pollution by aboveground plant parts.

Italian stone pine (Pinus pinea L.) and oleander (Nerium oleander L.) leaves, bark and wood samples were collected at different sites around an industrial area (Huelva, SW Spain) and compared with samples of the same species from a background site. Samples were analysed with respect to the following pollutants: Al, Ba, Cr, Cu, Fe and Pb by ICP-AES. The suitability of different plant parts as biomonitors of pollution was investigated. In pine samples from the polluted sites the ratio of concentrations between bark and wood was high for Al, Ba, Cu and Fe, whereas no differences were found in samples from the unpolluted area. No differences were detected in oleander for the same ratio. In the oleander species, the ratio between leaves and wood concentration allowed to distinguish between control and polluted sites. The ratio of the concentration between leaves and wood was elevated for Al, Ba and Fe in pine samples from the polluted sites. The ratio of the concentration in bark or leaves to their concentration in wood might be useful to detect inorganic atmospheric pollutants.

Air Pollutants↗

Determination of oleandrin in tissues and biological fluids by liquid chromatography-electrospray tandem mass spectrometry.

A rapid LC-MS/MS method, using a triple-quadrupole/linear ion trap mass spectrometer, was developed for the quantitative determination of oleandrin in serum, urine, and tissue samples. Oleandrin, the major cardiac glycoside of oleander (Nerium oleander L.), was extracted from serum and urine samples with methylene chloride and from tissues with acetonitrile. The tissue extracts were cleaned up using Florisil solid-phase extraction columns. Six replicate fortifications of serum and urine at 0.001 microg/g (1 ppb) oleandrin gave average recoveries of 97% with 5% CV (relative standard deviation) and 107% with 7% CV, respectively. Six replicate fortifications of liver at 0.005 microg/g (5 ppb) oleandrin gave average recoveries of 98% with 6% CV. This is the first report of a positive mass spectrometric identification and quantitation of oleandrin in tissue samples from oleander intoxication cases. The sensitivity and specificity of the LC-MS/MS analysis enables it to be the method of choice for toxicological investigations of oleander poisoning.

Animals↗

Cotranscription of genes encoding indoleacetic acid production in Pseudomonas syringae subsp. savastanoi.

Indoleacetic acid (IAA) production by the plant pathogen Pseudomonas syringae subsp. savastanoi is essential for tumor formation on olive and oleander. The bacterium produces IAA from tryptophan in reactions catalyzed by tryptophan monooxygenase and indoleacetamide hydrolase. The genetic determinants are, respectively, iaaM and iaaH. In oleander isolates, the genes encoding the IAA biosynthetic enzymes are located on a plasmid; in olive isolates, the genes occur on the chromosome. The IAA genes from the oleander isolate strain EW2009 are located within a 4-kilobase (kb) segment of the 52-kb plasmid pIAA1. Escherichia coli strains harboring a recombinant plasmid, pCJP3, which contains this 4-kb fragment, excreted IAA into culture media, and crude cell extracts had both tryptophan monooxygenase and indoleacetamide hydrolase activity. In vitro coupled transcription-translation of pCJP3 demonstrated that this fragment coded for proteins of 62 and 47 kilodaltons which correspond to tryptophan monooxygenase and indoleacetamide hydrolase, respectively. Expression of these genes was dependent upon a vector promoter in pCJP3. However, in the absence of a vector promoter, E. coli containing recombinant plasmids with additional pIAA1 DNA in front of iaaM had high levels of tryptophan monooxygenase. Northern (RNA) hybridization experiments verified that iaaM and iaaH are cotranscribed as a portion of a ca. 4- to 5-kb transcript in vivo. Southern hybridization experiments with IAA plasmids from different oleander strains of P. syringae subsp. savastanoi revealed that all IAA plasmids contained a region of at least 10 kb of homology, with the IAA genes at one end. Repetitive DNA and a copy of IS51 were found at the end of this region of homology.

Amidohydrolases↗

Naturally occurring cardiac glycosides.

Cardiac glycoside poisoning from the ingestion of plants, particularly of oleanders, occurs with reasonable frequency in tropical and subtropical areas. We have assessed a variety of plant specimens for their cardiac glycoside content by means of radioimmunoassays with antibodies that differ in their specificity for cardiac glycosides. Significant amounts of immunoreactive cardiac glycoside were found to be present in the ornamental shrubs: yellow oleander (Thevetia peruviana); oleander (Nerium oleander); wintersweet (Carissa spectabilis); bushman's poison (Carissa acokanthera); sea-mango (Cerbera manghas); and frangipani (Plumeria rubra); and in the milkweeds: redheaded cotton-bush (Asclepias curassavica); balloon cotton (Asclepias fruiticosa); king's crown (Calotropis procera); and rubber vine (Cryptostegia grandifolia). The venom gland of the cane toad (Bufo marinus) also contained large quantities of cardiac glycosides. The competitive immunoassay method permits the rapid screening of specimens that are suspected to contain cardiac glycosides. Awareness of the existence of these plant and animal toxins and their dangers allows them to be avoided and poisoning prevented. The method is also useful for the confirmation of the presence of cardiac glycosides in serum in cases of poisoning.

Amphibian Venoms↗

Phytoremediation of petroleum hydrocarbons in tropical coastal soils. I. Selection of promising woody plants.

GOAL, SCOPE AND BACKGROUND: This glasshouse study is aimed at evaluating tropical plants for phytoremediation of petroleum hydrocarbon-contaminated saline sandy subsurface soils. Tropical plants were selected for their ability to tolerate high salinity and remove No. 2 diesel fuel in coastal topsoil prior to further investigation of the phytoremediation feasibility in deep contaminated soils. The residual petroleum-hydrocarbon contaminant at the John Rogers Tank Farm site, a former petroleum storage facility, at Hickam Air Force Base, Honolulu, Hawaii, is located in a coastal area. It lies below a layer of silt in the subsurface, in loamy sand characterized by moderate salinity and high pH. Little is known regarding the ability of tropical plants to remediate petroleum hydrocarbon-contaminated subsurface soil in Hawaiian and other Pacific Island ecosystems although suitable plants have been identified and utilized for bioremediation in surface soil or marine sediments. METHODS: The experiments were conducted in long narrow pots under glasshouse conditions in two phases. A preliminary experiment was done with nine tropical plants: kiawe (Prosopis pallida), milo (Thespesia populnea), common ironwood (Casuarina equisetifolia), kou (Cordia subcordata), tropical coral tree (Erythrina variegata), false sandalwood (Myoporum sandwicense), beach naupaka (Scaevola sericea), oleander (Nerium oleander), and buffelgrass (Cenchrus ciliaris). These plants were screened for resistance to high salinity treatment (2% NaCl) and two diesel fuel levels (5 and 10 g No. 2 diesel fuel/kg soil) in separate treatments. Plants that showed good tolerance of both factors were further evaluated in a second phase for their efficacy in the phytoremediation of diesel-fuel petroleum hydrocarbons under moderate salinity treatment (1% NaCl). RESULTS: Tropical coral tree and buffelgrass were susceptible to either 2% NaCl or diesel fuel at 10 g/kg soil, but tolerant of diesel fuel at 5 g/kg soil. Kiawe, milo, kou, common ironwood, N. oleander, beach naupaka and false sandalwood were tolerant of high salinity (2% NaCl) or high diesel fuel level (10 g/kg soil). These seven plants were also tolerant of the combined adverse effects of a moderate salinity (1% NaCl) and 10 g diesel fuel/kg soil. Three trees, kiawe, milo and kou significantly accelerated the degradation of petroleum hydrocarbons in the soil spiked with 10 g diesel fuel/kg soil under a moderate salinity treatment (1% NaCl). CONCLUSION: Thus the tropical woody plants, kiawe, milo and kou showed potential for use in phytoremediation of petroleum hydrocarbons in coastal tropical soils. RECOMMENDATIONS AND OUTLOOK: Two fast growing trees, milo and kou, appeared promising for further phytoremediation evaluation in experiments that simulate the soil profile at the field site.

Biodegradation, Environmental↗

Multiform biosynthetic pathway of syringyl lignin in angiosperms.

To clarify the pathway for biosynthesis of sinapyl alcohol in angiosperms, tracer experiments using stable isotopes were performed on robinia ( Robinia pseudoacacia L.), oleander ( Nerium indicum Mill.), magnolia ( Magnolia kobus DC.) and Arabidopsis thaliana (L.) Heynh. Precursors used in the experiment were (13)C- and (2)H ( D)-labeled [8-(13)C, 3-OCD(3)]ferulic acid and [8-(13)C, 3,5-OCD(3)]sinapic acid. The incorporation of labeled precursor into lignin was confirmed by gas chromatography-mass spectrometry of the products of derivatization followed by reductive cleavage. Crude extracts of differentiating xylem or stems from these plants were also assayed for 4-coumarate-CoA ligase (4CL; EC 6.2.1.12) activity using sinapic acid and ferulic acid as substrates. In robinia and oleander, 4CL activity toward sinapic acid was detected, and labeled sinapic acids were incorporated into syringyl lignin. These results indicate that robinia and oleander have a pathway that produces sinapyl alcohol from sinapic acid via sinapoyl-CoA. By contrast, in magnolia and Arabidopsis, 4CL activity toward sinapic acid could not be detected, and labeled sinapic acid was not incorporated into lignin. These results suggest that syringyl lignin biosynthesis in angiosperms operates via multiple pathways that depend on the species.

Acyl Coenzyme A↗

Resonance Raman spectra of plastocyanin and pseudoazurin: evidence for conserved cysteine ligand conformations in cupredoxins (blue copper proteins).

New resonance Raman (RR) spectra at 15 K are reported for poplar (Populus nigra) and oleander (Oleander nerium) plastocyanins and for Alcaligenes faecalis pseudoazurin. The spectra are compared with those of other blue copper proteins (cupredoxins). In all cases, nine or more vibrational modes between 330 and 460 cm-1 can be assigned to a coupling of the Cu-S(Cys) stretch with Cys ligand deformations. The fact that these vibrations occur at a relatively constant set of frequencies is testimony to the highly conserved ground-state structure of the Cu-Cys moiety. Shifts of the vibrational modes by 1-3 cm-1 upon deuterium exchange can be correlated with N-H...S hydrogen bonds from the protein backbone to the sulfur of the Cys ligand. There is marked variability in the intensities of these Cys-related vibrations, such that each class of cupredoxin has its own pattern of RR intensities. For example, plastocyanins from poplar, oleander, French bean, and spinach have their most intense feature at approximately 425 cm-1; azurins show greatest intensity at approximately 410 cm-1, stellacyanin and ascorbate oxidase at approximately 385 cm-1, and nitrite reductase at approximately 360 cm-1. These variable intensity patterns are related to differences in the electronic excited-state structures. We propose that they have a basis in the protein environment of the copper-cysteinate chromophore. A further insight into the vibrational spectra is provided by the structures of the six cupredoxins for which crystallographic refinements at high resolution are available (plastocyanins from P. nigra, O. nerium, and Enteromorpha prolifera, pseudoazurin from A. faecalis, azurin from Alcaligenes denitrificans, and cucumber basic blue protein). The average of the Cu-S(Cys) bond lengths is 2.12 +/- 0.05 A. Since the observed range of bond lengths falls within the precision of the determinations, this variation is considered insignificant. The Cys ligand dihedral angles are also highly conserved. Cu-S gamma-C beta-C alpha is always near -170 degrees and S gamma-C beta-C alpha-N near 170 degrees. As a result, the Cu-S gamma bond is coplanar with the Cys side-chain atoms and part of the polypeptide backbone. The coplanarity accounts for the extensive coupling of Cu-S stretching and Cys deformation modes as seen in the RR spectrum. The conservation of this copper-cysteinate conformation in cupredoxins may indicate a favored pathway for electron transfer.

Azurin↗

Comparison of water potentials measured by in situ psychrometry and pressure chamber in morphologically different species.

Leaf water potentials measured by in situ psychrometry were compared with leaf water potentials measured by the pressure chamber technique at various values of water potential in Helianthus annuus, Helianthus nuttallii, Vigna unguiculata, Nerium oleander, Pistacia vera, and Corylus avellana. In V. unguiculata, the leaf water potentials measured by the in situ psychrometer oscillated at the same periodicity as, and proportional to, the leaf conductance. In all species, potentials measured by in situ psychrometers operating in the psychrometric mode were linearly correlated with potentials measured with the pressure chamber. However, the in situ psychrometers underestimated the leaf water potential in the two Helianthus species at low water potentials and overestimated the water potential in P. vera, N. oleander, and C. avellana. The underestimation in the two Helianthus species at low water potentials resulted from differences in water potential across the leaf. The overestimation in P. vera, N. oleander, and C. avellana was considered to arise from low epidermal conductances in these species even after abrasion of the cuticle. Pressure-volume studies with Lycopersicon esculentum showed that less water was expressed from distal than proximal leaflets when the whole leaf was slowly pressurized. The implication of this for water relations characteristics obtained by pressure-volume techniques is discussed. We conclude that in situ psychrometers are suitable for following dynamic changes in leaf water potential, but should be used with caution on leaves with low epidermal conductances.

Journal Article↗

Phase transitions in thylakoid polar lipids of chilling-sensitive plants: a comparison of detection methods.

The phase behavior of thylakoid polar lipids from plants sensitive to chilling injury was investigated by calorimetry, electron spin resonance spectroscopy of spin labels, and fluorescence intensity after labeling with trans-parinaric acid. The plants used were oleander (Nerium oleander), mung bean (Vigna radiata L. var Mungo), and tomato (Lycopersicon esculentum cv Grosse Lisse). For all plants the initiation temperature for the calorimetric exotherm was coincident (+/-1 degrees C) with the transition determined by the increase in the temperature coefficient of spin label motion and fluorescence intensity of trans-parinaric acid. For oleander plants, grown at 45 degrees C, the transition was at 7 degrees C while for plants from the same clone, grown at 20 degrees C, it was at -2 degrees C. For mung bean and tomato the transition was between 9 and 12 degrees C. The similarity in the transition detected by spin labeling and fluorescence intensity suggest that spin labels, like the fluorescent label trans-parinaric acid, preferentially partition into domains of ordered lipid. The coincidence of the temperature for initiation of the transition, determined by the three techniques, shows that each is a valid method of assessing a phase transition in membrane polar lipids.

Journal Article↗

Genetic diversity of Pierce's disease strains and other pathotypes of Xylella fastidiosa.

Strains of Xylella fastidiosa isolated from grape, almond, maple, and oleander were characterized by enterobacterial repetitive intergenic consensus sequence-, repetitive extragenic palindromic element (REP)-, and random amplified polymorphic DNA (RAPD)-PCR; contour-clamped homogeneous electric field (CHEF) gel electrophoresis; plasmid content; and sequencing of the 16S-23S rRNA spacer region. Combining methods gave greater resolution of strain groupings than any single method. Strains isolated from grape with Pierce's disease (PD) from California, Florida, and Georgia showed greater than previously reported genetic variability, including plasmid contents, but formed a cluster based on analysis of RAPD-PCR products, NotI and SpeI genomic DNA fingerprints, and 16S-23S rRNA spacer region sequence. Two groupings of almond leaf scorch (ALS) strains were distinguished by RAPD-PCR and CHEF gel electrophoresis, but some ALS isolates were clustered within the PD group. RAPD-PCR, CHEF gel electrophoresis, and 16S-23S rRNA sequence analysis produced the same groupings of strains, with RAPD-PCR resolving the greatest genetic differences. Oleander strains, phony peach disease (PP), and oak leaf scorch (OLS) strains were distinct from other strains. DNA profiles constructed by REP-PCR analysis were the same or very similar among all grape strains and most almond strains but different among some almond strains and all other strains tested. Eight of 12 ALS strains and 4 of 14 PD strains of X. fastidiosa isolated in California contained plasmids. All oleander strains carried the same-sized plasmid; all OLS strains carried the same-sized plasmid. A plum leaf scald strain contained three plasmids, two of which were the same sizes as those found in PP strains. These findings support a division of X. fastidiosa at the subspecies or pathovar level.

Bacterial Typing Techniques↗

Inhibition of Na,K-ATPase by oleandrin and oleandrigenin, and their detection by digoxin immunoassays.

Ingestion of oleander plant, containing the cardiac glycoside oleandrin, has been reported to induce fatal poisonings. Derivatives of oleandrin are structurally similar to digoxin. We investigated the cross-reactivities of oleandrin and its aglycone metabolite, oleandrigenin, in several commercially available digoxin immunoassays; assessed their ability to inhibit Na,K-ATPase catalytic activity; and measured their binding to proteins in serum. As assayed with ACS:180, Stratus, RIA, On-Line, and TDx digoxin assays, oleandrin at 100 micromol/L in digoxin-free serum gave apparent digoxin values of 0, 0.83, 2.24, 2.37, and 5.34 nmol/L, respectively, whereas oleandrigenin at that concentration gave results of 0, 0.52, 0.77, 4.94, and 1.40 nmol/L. Study of Na,K-ATPase inhibition showed IC50 values (micromol/L) of 0.22 for ouabain, 0.62 for oleandrin, 1.23 for oleandrigenin, and 2.69 for digoxin. At 25 degrees C, 96% of oleandrin and 48% of oleandrigenin were bound to serum proteins. Because detection of oleandrin and oleandrigenin by digoxin immunoassays is variable between assays as well as between congeners, assessment of cross-reactivity is warranted for each assay. The inhibition of Na,K-ATPase by oleandrin and oleandrigenin confirms that they likely exert their toxic effects through inhibition of sodium pump activity. In cases of digitalis-like poisoning with suspicion of oleander ingestion, a combination of digoxin immunoassays may be useful to effectively rule out the presence of oleander.

Blood Proteins↗

Characterization of high-frequency deletions in the iaa-containing plasmid, pIAA2, of Pseudomonas syringae pv. savastanoi.

The phytopathogenic bacterium Pseudomonas syringae pv. savastanoi causes olive and oleander knot disease. The bacterium induces the formation of tumorous galls by the synthesis and secretion of the plant hormones trans-zeatin riboside and indole-3-acetic acid into host intercellular spaces. An Italian oleander isolate, PB213, has been observed to lose the ability to synthesize IAA at high frequency, thus becoming non-pathogenic. The IAA genes, located on the 72-kb iaa-containing plasmid, pIAA2 were lost mainly due to two classes of deletions: 18 or 22 kb in length. Both classes of deletions had a common endpoint upstream of the IAA genes. The other endpoints were in areas that flanked the insertion sequence element IS51. The endpoints are in regions of repetitive DNA of at least 271 bp that have been designated a/b.

Base Sequence↗

Phytoremediation of petroleum hydrocarbons in tropical coastal soils. II. Microbial response to plant roots and contaminant.

GOAL, SCOPE AND BACKGROUND: The goal of this study was to understand the interaction between plants and microorganisms during petroleum-hydrocarbon bioremediation in Pacific Islands coastal soils. Total bacteria and hydrocarbon-degrading microorganisms population dyanamics were examined in the rhizospheres of tropical trees and shrubs, which were evaluated for their phytoremediation potential in a greenhouse experiment. The respective and combined effects of plant roots and diesel contaminant on the microbial populations were determined in relation to diesel fuel depletion. An increase in the grading populations size of the hydrocarbon-degrading populations of microbes, elicited by rhizodeposition, is generally regarded as conducive to an enhanced degradation of petroleum hydrocarbon pollutants in vegetated soil. METHODS: The soil was a coastal sandy loam (pH 7.8) which was artificially contaminated with 10 g of No. 2 diesel fuel/kg soil or left uncontaminated. The pots were irrigated with fertilizer and 1% NaCl. The enumerations were carried out in the contaminated and uncontaminated rhizospheres of three trees, kiawe (Prosopis pallida), milo (Thespesia populnea), and kou (Cordia subcordata) and three shrubs, beach naupaka (Scaevola sericea), false sandalwood (Myoporum sandwicense), and oleander (Nerium oleander). Unplanted control soils were included in the experiment. Total bacteria and phenanthrene-degrading bacteria were enumerated on plates. Diesel- and pristane-degrading microorganisms were enumerated by the most-probable-number technique in tissue-culture plates. RESULTS AND DISCUSSION: All four types of microorganisms responded to the rhizosphere of the 6 plants in uncontaminated soil and to the diesel contaminant in unplanted soil. In contaminated rhizospheres, no effect of the plant on the hydrocarbon-degrader numbers was visible. Total bacteria responded more to the plant roots than to the contaminant. The phenanthrene-degrading bacteria and pristane-degrading microorganisms were more influenced by the contaminant than by the plants. The diesel-degrading microorganisms were equally stimulated by the plants and the contaminant. The numbers of hydrocarbon degraders were similar in the contaminated rhizospheres of the three effective plants (kiawe, kou, and milo) and in those of the three ineffective shrubs. CONCLUSION: The results suggest the quality of the rhizodeposition is plant-dependent and governs the type of diesel-degrader populations that will be enhanced by a given plant. RECOMMENDATIONS AND OUTLOOK: In the proposed phytoremediation-benefit model plant roots maintain high levels of hydrocaron degraders in uncontaminated soil. When the root enters a contaminated zone of soil, those hydrocarbon degraders that prefer the contaminant would switch to the contaminant as a carbon source, effectively removing the hydrocarbons. If the root exudates and the contaminant are equally attractive to the hydrocarbon degraders, the contaminant degradaton would be less effective.

Biodegradation, Environmental↗

Isolation and phylogenetic analysis of Xylella fastidiosa from its invasive alternative host, porcelain berry.

A strain of Xylella fastidiosa was isolated from an invasive alternative host species, porcelain berry. Its genetic relationship with strains isolated from a native alternative host, wild grape; a nonnative alternative host, mulberry; and other economically important hosts including cultivated grape, peach, plum, oak, maple and oleander was determined by using sequence analysis of the 16S-23S rRNA intergenic spacer region. Our phylogenetic analysis revealed that the porcelain berry strain is most closely related to the wild grape strain. These two strains are more closely related to the oak, peach, and plum strains than to the mulberry and oleander strains. They are separated from the maple and cultivated grape strains. Our data suggest that suppression of porcelain berry, wild grape, and mulberry in the vicinity of susceptible economically important hosts such as oak, peach, and plum may provide an important control measure for diseases caused by X. fastidiosa.

Base Sequence↗

Structural analysis of xyloglucans in the primary cell walls of plants in the subclass Asteridae.

The structures of xyloglucans from several plants in the subclass Asteridae were examined to determine how their structures vary in different taxonomic orders. Xyloglucans, solubilized from plant cell walls by a sequential (enzymatic and chemical) extraction procedure, were isolated, and their structures were characterized by NMR spectroscopy and mass spectrometry. All campanulids examined, including Lactuca sativa (lettuce, order Asterales), Tenacetum ptarmiciflorum (dusty miller, order Asterales), and Daucus carota (carrot, order Apiales), produce typical xyloglucans that have an XXXG-type branching pattern and contain alpha-d-Xylp-, beta-D-Galp-(1-->2)-alpha-D-Xylp-, and alpha-L-Fucp-(1-->2)-beta-D-Galp-(1-->2)-alpha-D-Xylp- side chains. However, the lamiids produce atypical xyloglucans. For example, previous analyses showed that Capsicum annum (pepper) and Lycopersicon esculentum (tomato), two species in the order Solanales, and Olea europaea (olive, order Lamiales) produce xyloglucans that contain arabinosyl and galactosyl residues, but lack fucosyl residues. The XXGG-type xyloglucans produced by Solanaceous species are less branched than the XXXG-type xyloglucan produced by Olea europaea. This study shows that Ipomoea pupurea (morning glory, order Solanales), Ocimum basilicum (basil, order Lamiales), and Plantago major (plantain, order Lamiales) all produce xyloglucans that lack fucosyl residues and have an unusual XXGGG-type branching pattern in which the basic repeating core contains five glucose subunits in the backbone. Furthermore, Neruim oleander (order Gentianales) produces an XXXG-type xyloglucan that contains arabinosyl, galactosyl, and fucosyl residues. The appearance of this intermediate xyloglucan structure in oleander has implications regarding the evolutionary development of xyloglucan structure and its role in primary plant cell walls.

Alcohols↗

Anti-inflammatory and antinociceptive activity assessment of plants used as remedy in Turkish folk medicine.

Ethanolic and aqueous extracts from seven plant species used in Turkish traditional medicine were evaluated for in vivo anti-inflammatory and antinociceptive activities; Helleborus orientalis Lam. roots and herbs, Juglans regia L. leaves, Laurocerasus officinalis Roemer leaves, Nerium oleander L. dried and fresh flowers and leaves, Rhododendron ponticum L. leaves, Rubus hirtus Walds. et Kit aerial parts and Rubus sanctus Schreber aerial parts and roots. All the plant extracts, except the aqueous extract of Rubus hirtus, were shown to possess significant antinociceptive activity in varying degrees against p-benzoquinone-induced abdominal contractions in mice. However, only the ethanolic extracts of Helleborus orientalis roots, Juglans regia leaves, Laurocerasus officinalis leaves, Nerium oleander dried and fresh flowers, and Rhododendron ponticum leaves exhibited potent anti-inflammatory activity against carrageenan-induced hind paw edema model in mice without inducing any gastric damage. Results of the present study confirmed the folkloric claim that all the selected materials to possess potent antinociceptive and anti-inflammatory activity.

Analgesics↗

Evidence for the biosynthetic pathway from sinapic acid to syringyl lignin using labeled sinapic acid with stable isotope at both methoxy groups in Robinia pseudoacacia and Nerium indicum.

A tracer experiment using synthesized labeled lignin precursors was designed to confirm the actual biosynthetic pathway for syringyl lignin. Tetradeuteroferulic acid-[8-D, 3-OCD(3)] and heptadeuterosinapic acid-[8-D, 3,5-OCD(3)] were synthesized and fed to shoots of robinia (Robinia pseudoacacia) and oleander (Nerium indicum) trees. The incorporation of each labeled precursor into lignin was traced by gas chromatography-mass spectrometry. The synthesized sinapic acid, in which both methoxy groups were labeled, was useful in monitoring the conversion of sinapic acid into syringyl lignin. When heptadeuterosinapic acid was fed, syringyl units containing seven deuterium labels were detected. The results of this study support the traditionally accepted pathway that sinapic acid is converted to sinapyl alcohol via sinapoyl-CoA in robinia and oleander.

Acyl Coenzyme A↗

Whole-genome comparative analysis of three phytopathogenic Xylella fastidiosa strains.

Xylella fastidiosa (Xf) causes wilt disease in plants and is responsible for major economic and crop losses globally. Owing to the public importance of this phytopathogen we embarked on a comparative analysis of the complete genome of Xf pv citrus and the partial genomes of two recently sequenced strains of this species: Xf pv almond and Xf pv oleander, which cause leaf scorch in almond and oleander plants, respectively. We report a reanalysis of the previously sequenced Xf 9a5c (CVC, citrus) strain and the two "gapped" Xf genomes revealing ORFs encoding critical functions in pathogenicity and conjugative transfer. Second, a detailed whole-genome functional comparison was based on the three sequenced Xf strains, identifying the unique genes present in each strain, in addition to those shared between strains. Third, an "in silico" cellular reconstruction of these organisms was made, based on a comparison of their core functional subsystems that led to a characterization of their conjugative transfer machinery, identification of potential differences in their adhesion mechanisms, and highlighting of the absence of a classical quorum-sensing mechanism. This study demonstrates the effectiveness of comparative analysis strategies in the interpretation of genomes that are closely related.

Bacterial Proteins↗