The gene stlA encodes a phenylalanine ammonia-lyase that is involved in the production of a stilbene antibiotic in Photorhabdus luminescens TT01

Microbiology ◽  
2005 ◽  
Vol 151 (8) ◽  
pp. 2543-2550 ◽  
Author(s):  
Jane S. Williams ◽  
Marie Thomas ◽  
David J. Clarke
Keyword(s):  
Phenylalanine Ammonia Lyase ◽  
Complex Life Cycle ◽  
Photorhabdus Luminescens ◽  
Insect Larvae ◽  
Pal Activity ◽  
Feeding Experiments ◽  
The Family ◽  
Mutualistic Relationship ◽  
Pathogenic Interaction ◽  
Biochemical Analyses

Photorhabdus is a genus of Gram-negative bacteria from the family Enterobacteriaceae. Members of Photorhabdus have a complex life cycle during which the bacterium has a pathogenic interaction with insect larvae whilst also maintaining a mutualistic relationship with nematodes from the family Heterorhabditidae. During growth in the insect, Photorhabdus bacteria produce a broad-spectrum antibiotic identified as 3,5-dihydroxy-4-isopropylstilbene (ST). The biochemical pathway responsible for the production of this antibiotic has not been characterized. In this report, a mutant strain of Photorhabdus luminescens subsp. laumondii TT01, BMM901, has been isolated, by transposon mutagenesis, that is unable to produce the ST antibiotic. Using in silico studies, feeding experiments and biochemical analyses, it is shown that the gene mutated in this strain, stlA, encodes phenylalanine ammonia-lyase (PAL). PAL catalyses the non-oxidative deamination of l-phenylalanine to trans-cinnamic acid and the enzyme is ubiquitous in plants, where it is involved in the production of phenylpropanoids such as lignin and phytoalexins. However, this is the first report of PAL activity in a member of the Proteobacteria.

Cuttings of the non-rooting rac tobacco mutant overaccumulate phenolic compounds

2002 ◽  
Vol 29 (1) ◽  
pp. 63 ◽  
Author(s):  
Odile Faivre-Rampant ◽  
Jean-Paul Charpentier ◽  
Claire Kevers ◽  
Jacques Dommes ◽  
Harry Van Onckelen ◽  
...  
Keyword(s):  
Chlorogenic Acid ◽  
Adventitious Roots ◽  
Phenylalanine Ammonia Lyase ◽  
Wild Type ◽  
Growth Limitation ◽  
Phenolic Contents ◽  
Pal Activity ◽  
Culture Cycle ◽  
Biochemical Analyses

The auxin and phenolic contents, as well as phenylalanine ammonia-lyase (PAL) activity, were determined in in vitro cultured shoots of the recalcitrant-to-root rac mutant of tobacco, and compared with wild-type shoots. The mutant and wild-type shoots showed similar auxin changes during the culture cycle, but with higher contents for the mutant. A transient peak of auxin (corresponding to the achievement of the rooting inductive phase) occurred at day 14 in both types of shoots, but earlier in the basal parts of the wild-type stems. The rac shoots contained more phenolics, corresponding with an increased PAL activity. The most abundant phenolic compound found in the two types of tobacco was chlorogenic acid, which was more abundant in the rac shoots. Rutin was also detected at a higher concentration in the mutant shoots. Basal parts of wild-type shoots treated with 10–3 M chlorogenic acid reacted by accumulating auxins and, unlike untreated controls, did not form adventitious roots. The relationships between these biochemical analyses in relation to the growth limitation of the rac mutant, and the inhibition of its root development, are discussed.

scholarly journals The pbgPE operon in Photorhabdus luminescens Is Required for Pathogenicity and Symbiosis

2005 ◽  
Vol 187 (1) ◽  
pp. 77-84 ◽  
Author(s):  
H. P. J. Bennett ◽  
D. J. Clarke
Keyword(s):  
Galleria Mellonella ◽  
Polymyxin B ◽  
Infective Juvenile ◽  
Acidic Ph ◽  
Photorhabdus Luminescens ◽  
Insect Larvae ◽  
Cationic Antimicrobial Peptide ◽  
O Antigen ◽  
Mutualistic Relationship ◽  
Increased Sensitivity

ABSTRACT Photorhabdus is a genus of gram-negative Enterobacteriaceae that is pathogenic to insect larvae while also maintaining a mutualistic relationship with nematodes from the family Heterorhabditis, where the bacteria occupy the gut of the infective juvenile (IJ) stage of the nematode. In this study we describe the identification and characterization of a mutation in the pbgE1 gene of Photorhabdus luminescens TT01, predicted to be the fifth gene in the pbgPE operon. We show that this mutant, BMM305, is strongly attenuated in virulence against larvae of the greater wax moth, Galleria mellonella, and we report that BMM305 is more sensitive to the cationic antimicrobial peptide, polymyxin B, and growth in mildly acidic pH than the parental strain of P. luminescens. Moreover, we also show that the lipopolysaccharide (LPS) present on the surface of BMM305 does not appear to contain any O antigen. Complementation studies reveal that the increased sensitivity to polymyxin B and growth in mildly acidic pH can be rescued by the in trans expression of pbgE1, while the defects in O-antigen assembly and pathogenicity require the in trans expression of pbgE1 and the downstream genes pbgE2 and pbgE3. Finally, we show that BMM305 is defective in symbiosis as this mutant is unable to colonize the gut of the IJ stage of the nematode. Therefore, we conclude that the pbgPE operon is required for both pathogenicity and symbiosis in P. luminescens.

scholarly journals Effects of Polysaccharide Elicitors on Secondary Metabolite Production and Antioxidant Response inHypericum perforatumL. Shoot Cultures

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Sonja Gadzovska Simic ◽  
Oliver Tusevski ◽  
Stéphane Maury ◽  
Alain Delaunay ◽  
Claude Joseph ◽  
...  
Keyword(s):  
Phenylalanine Ammonia Lyase ◽  
Hypericum Perforatum ◽  
Total Phenolics ◽  
Antioxidant Properties ◽  
Redox System ◽  
Antioxidant Response ◽  
Defense Responses ◽  
Shoot Cultures ◽  
Significant Suppression ◽  
Pal Activity

The effects of polysaccharide elicitors such as chitin, pectin, and dextran on the production of phenylpropanoids (phenolics and flavonoids) and naphtodianthrones (hypericin and pseudohypericin) inHypericum perforatumshoot cultures were studied. Nonenzymatic antioxidant properties (NEAOP) and peroxidase (POD) activity were also observed in shoot extracts. The activities of phenylalanine ammonia lyase (PAL) and chalcone-flavanone isomerase (CHFI) were monitored to estimate channeling in phenylpropanoid/flavonoid pathways of elicited shoot cultures. A significant suppression of the production of total phenolics and flavonoids was observed in elicited shoots from day 14 to day 21 of postelicitation. This inhibition of phenylpropanoid production was probably due to the decrease in CHFI activity in elicited shoots. Pectin and dextran promoted accumulation of naphtodianthrones, particularly pseudohypericin, within 21 days of postelicitation. The enhanced accumulation of naphtodianthrones was positively correlated with an increase of PAL activity in elicited shoots. All tested elicitors induced NEAOP at day 7, while chitin and pectin showed increase in POD activity within the entire period of postelicitation. The POD activity was in significantly positive correlation with flavonoid and hypericin contents, suggesting a strong perturbation of the cell redox system and activation of defense responses in polysaccharide-elicitedH. perforatumshoot cultures.

Effects of Herbicides on Growth and Extractable Phenylalanine Ammonia-Lyase Activity in Light- and Dark-Grown Soybean (Glycine max) Seedlings

Weed Science ◽  
1981 ◽  
Vol 29 (4) ◽  
pp. 433-439 ◽  
Author(s):  
Robert E. Hoagland ◽  
Stephen O. Duke
Keyword(s):  
Glycine Max ◽  
Phenylalanine Ammonia Lyase ◽  
Dry Weight ◽  
Root Tip ◽  
Continuous Darkness ◽  
Soybean Seedlings ◽  
Pal Activity ◽  
Lyase Activity ◽  
Phenylalanine Ammonia Lyase Activity

Effects of 16 herbicides representing 14 herbicide classes on growth and extractable phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) were examined in light- and dark-grown soybean [Glycine max(L.) Merr. ‘Hill’] seedlings. High purity (96 to 100%) herbicides were supplied via aqueous culture at various concentrations: 0.5 mM amitrole (3-amino-s-triazole), 0.1 mM atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine], 0.07 mM diclofop-methyl {methyl ester of 2-[4-(2,4-dichlorophenoxy)phenoxy] propanoicacid}, 0.5 mM DSMA (disodium methanearsonate), 0.2 mM fenuron (1,1-dimethyl-3-phenylurea), 0.05 mM fluridone {1-methyl-3-phenyl-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone}, 0.5 mM MH (1,2-dihydro-3,6-pyridazinedione), 0.5 mM metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)-one], 1.8 μM nitralin [4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline], 0.5 mM norflurazon [4-chloro-5-(methylamino)-2-(α,α,α-trifluoro-m-tolyl)-3(2H)-pyridazinone], 0.05 mM paraquat (1,1′-dimethyl-4,4′-bipyridinium ion), 0.15 mM perfluidone {1,1,1-trifluoro-N-[2-methyl-4-(phenylsulfonyl)phenyl] methanesulfonamide}, 0.2 mM propanil (3′,4′-dichloropropionanilide), 0.1 mM propham (isopropyl carbanilate), 0.5 mM TCA (trichloroacetic acid), and 0.05 mM 2,4-D [(2,4-dichlorophenoxy)acetic acid]. Dark-grown soybean seedlings (3-day-old) were transferred to control solutions (2 mM CaSO4) or to herbicide solutions (in 2 mM CaSO4) and grown at 25 C in continuous white light (200 μE•m-2•s-1) or continuous darkness until harvested 24 or 48 h after transfer. After 48 h, growth (fresh weight, dry weight, elongation) was inhibited by most of the chemicals. Other signs of toxicity (necrosis, secondary root stunting, and root tip swelling) were noted for some treatments. Roots were most affected, although hypocotyls were generally not changed. Hypocotyl elongation was stimulated by atrazine, fluridone, and norflurazon after 48 h light. Extractable PAL activity from soybean axes was decreased by atrazine, fenuron, metribuzin, norflurazon, propanil, propham, and 2,4-D. Amitrole and paraquat were the only herbicides that increased extractable PAL activity. Other compounds tested had no effect on the enzyme. None of the herbicides significantly affected in vitro PAL activity.

scholarly journals Postharvest Quality of Cut Roses With the Application of Salicylic Acid

2018 ◽  
Vol 10 (8) ◽  
pp. 397
Author(s):  
Sérgio Miguel Mazaro ◽  
Edson Bertoldo ◽  
Nean Locatelli Dalacosta ◽  
Fabiana Chiamulera Borsatti ◽  
Mycheli Preuss da Cruz ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Defense Mechanisms ◽  
Phenylalanine Ammonia Lyase ◽  
Postharvest Quality ◽  
Fresh Matter ◽  
Leaf Chlorophyll ◽  
Biochemical Analyses ◽  
Stem Curvature ◽  
Lower Stem

The objective of this work was to evaluate the effect of the application of salicylic acid (SA) on the maintenance of quality and longevity of cut roses cv. Vega. Cut roses were kept in a vase solution of SA and water at concentrations of 0; 0.5; 1.0; 1.5 and 2.0 mM. All treatments were kept at 8±2 oC for 96 hours, simulating storage in flower shops; the flowers were then evaluated regarding loss of fresh matter and leaf chlorophyll content and were transferred to beakers containing distilled water at 25±2 ºC for more 144 hours, simulating shelf life. At 24, 48, 72 and 96 hours from the beginning of the experiment, biochemical analyses of total proteins and the activity of the phenylalanine ammonia-lyase (PAL) and peroxidases (PO) were performed. Visual analyses were performed (stem curvature, turgescence and petal darkening) every 48 hour intervals until the end of the experiment. The treatments with SA allowed the maintenance of post-harvest quality, reducing the loss of fresh matter mass, lower stem curvature, greater turgescence and less darkening of the petals. The results showed that the application of SA increased total protein contents and FAL, which characterizes the activation of plant defense mechanisms to the senescence process.

Effects of PGPR (Pseudomonas sp.) and Ag-nanoparticles on Enzymatic Activity and Physiology of Cucumber

2020 ◽  
Vol 11 (2) ◽  
pp. 124-136 ◽  
Author(s):  
Sehrish Nawaz ◽  
Asghari Bano
Keyword(s):  
Superoxide Dismutase ◽  
Pseudomonas Putida ◽  
Ag Nanoparticles ◽  
Phenylalanine Ammonia Lyase ◽  
Combined Treatment ◽  
Pseudomonas Stutzeri ◽  
Plant Growth Promoting Rhizobacteria ◽  
Vegetative Phase ◽  
Pal Activity ◽  
Plant Growth Promoting

Background: The present investigation aimed to evaluate the role of Plant Growth- Promoting Rhizobacteria (PGPR) and Ag-nanoparticles on two varieties (American variety, Poinsett 76 and Desi variety, Sialkot selection) of cucumber plants. Methods: Cucumber seeds prior to sowing, were inoculated with two strains of PGPR, Pseudomonas putida (KX574857) and Pseudomonas stutzeri (KX574858) at the rate of 106 cells/ml. Agnanoparticles (5ppm) were sprayed on the plant at early vegetative phase 27 d after sowing. Results: The proline, sugar, protein, phenolics, flavonoids, chlorophyll and carotenoids contents of leaves of plants and the activities of Phenylalanine Ammonia-Lyase (PAL), Superoxide Dismutase (SOD) and Catalase (CAT) were determined from leaves of plants at early vegetative phase. After 3 months of seeds sowing, Ag-nanoparticles enhanced the length of root but decreased the length of shoot and fresh weight of root and shoot as compared to control whereas, the leaf protein, proline, phenolics, flavonoids, chlorophyll b, total chlorophyll, sugar and Phenylalanine Ammonia-Lyase (PAL) activity of plants were increased significantly over control. Ag-nanoparticles also suppressed the effect of PGPR for root, shoot length but augmented the protein and phenolics contents of leaves of both the varieties. Conclusion: The combined treatment of Ag-nanoparticles and PGPR enhanced flavonoids content of leaves and the activities of PAL, SOD and CAT in leaves of plants over control. Agnanoparticles effectively increased the Phenylalanine Ammonia-Lyase (PAL), Catalase (CAT) and superoxide dismutase (SOD) activities in leaves of both the varieties. Pseudomonas putida may be used either alone or in combination with Ag-nanoparticles to enhance the antioxidant and defense enzyme activities. Hence, the plant can tolerate the diseases and stresses in a much better way with higher protein and phenolics content.

Development of Proteocephalus torulosus in the intermediate host under experimental conditions

1993 ◽  
Vol 67 (4) ◽  
pp. 316-324 ◽  
Author(s):  
T. Scholz
Keyword(s):  
Intermediate Host ◽  
Middle Layer ◽  
Cyprinid Fish ◽  
Outer Envelope ◽  
Experimental Conditions ◽  
Feeding Experiments ◽  
Scardinius Erythrophthalmus ◽  
The Family ◽  
Hyaline Membrane ◽  
Different Temperatures

AbstractThe development of the tapeworm Proteocephalus torulosus (Batsch, 1786) (Cestoda: Proteocephalidae), a parasite of cyprinid fish, was studied in the intermediate host under experimental conditions. The eggs of P. torulosus were typified by a relatively small outer envelope (hyaline membrane) and a thick middle layer surrounding the oncosphere. Incubation of P. torulosus eggs at different temperatures revealed the ability of some oncospheres to survive and remain infective to the intermediate host for up to 5 weeks at 5–7°C, 12 days at 10–12°C, and 8 days at 20–22°C. Of 8 copepod species used in these experiments, complete development of larvae was observed only in Cyclops strenuus. Growth was completed in 9–12 days at 20–22°C and four weeks at 9–10°C. During development the cercomer was not observed. The infectivity of larvae from C. strenuus for the definitive hosts, cyprinid fish, was very low and only one chub of 26 fish used for feeding experiments (21 chub, Leuciscus cephalus, 3 bleak, Alburnoides bipunctatus, 1 rudd, Scardinius erythrophthalmus—all the family Cyprinidae, and 1 loach, Noemacheilus barbatulus—the family Cobitidae) became infected.

scholarly journals Monitoring of the PAL Enzymatic Activity and Polyphenolic Compounds in Leaves and Fruits of Two Myrtle Cultivars during Maturation

Agriculture ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 389
Author(s):  
Silvia Medda ◽  
Leonarda Dessena ◽  
Maurizio Mulas
Keyword(s):  
Phenolic Compounds ◽  
Phenylalanine Ammonia Lyase ◽  
Raw Materials ◽  
Phenylpropanoid Pathway ◽  
Polyphenolic Compounds ◽  
Antioxidant Compounds ◽  
Total Polyphenols ◽  
Spectrophotometric Methods ◽  
Pal Activity ◽  
Potential Use

The leaves and berries of myrtle (Myrtus communis L.) are rich in phenolic compounds, such as phenolic acids, flavonoids, and flavanols. The richness of these antioxidant compounds allows the potential use of myrtle biomasses as raw materials for medicinal and functional food products. Most of the phenolic compounds originate from the phenylpropanoid pathway, where phenylalanine ammonia lyase (PAL) enzyme activates the first step. The objective of this research is to study the activity of PAL as related to accumulation in the myrtle fruits and leaves of some phenolic compounds in the period between blossom and full berry ripening. With this aim, we compared two model genotypes with different fruit coloration. In leaves and berries of two cultivars, ‘Giovanna’ with pigmented berries and ‘Grazia’ with white berries, the PAL activity and content of polyphenols, anthocyanins, flavonoids, and tannins were determined with spectrophotometric methods. PAL activity was quite constant in leaves and variable in berries: Greater in berries of ‘Giovanna’ than in those of ‘Grazia’ cultivar, and increasing from berry color-break to full ripening. In berries, a positive correlation between PAL and flavonoids (r = 0.44), and between PAL and anthocyanins (r = 0.69), as well as a negative correlation between PAL and total polyphenols (r = −0.471), were found.

Acifluorfen Action on Growth and Phenolic Metabolism in Soybean (Glycine max) Seedlings

Weed Science ◽  
1989 ◽  
Vol 37 (6) ◽  
pp. 743-747 ◽  
Author(s):  
Robert E. Hoagland
Keyword(s):  
Glycine Max ◽  
Chlorophyll A ◽  
Root Elongation ◽  
Liquid Culture ◽  
Phenylalanine Ammonia Lyase ◽  
Hypocotyl Length ◽  
Phenolic Metabolism ◽  
Soybean Seedlings ◽  
Pal Activity ◽  
Chlorophyll Accumulation

Three-day-old soybean seedlings were treated with acifluorfen via liquid culture [50 μM in dark, 1 μM in light (200 μE·m–2·s–1)]. Root elongation in the dark was inhibited only slightly (6%) after 96 h. In the light, acifluorfen inhibited root elongation after 48 h; after 96 h, inhibition was 32%. Hypocotyl length was not affected in either the light or dark. Soluble hydroxyphenolic content per axis was unaffected in the dark but was reduced by about 13 to 25% at 24 to 96 h in the light. Extractable phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) activity per axis was unaltered by herbicide in the dark. A brief transient increase in PAL activity (4 to 24 h) in axes of light-grown seedlings in the presence of acifluorfen was followed by reduced enzyme levels compared to light-grown controls at 72 and 96 h. Although light is required for maximal herbicide action, there was no effect on anthocyanin or chlorophyll accumulation or on the chlorophyll a/b ratio in hypocotyls or light-grown seedlings.

scholarly journals The Mandelate Pathway, an Alternative to the Phenylalanine Ammonia Lyase Pathway for the Synthesis of Benzenoids in Ascomycete Yeasts

2020 ◽  
Vol 86 (17) ◽  
Author(s):  
Maria Jose Valera ◽  
Eduardo Boido ◽  
Juan Carlos Ramos ◽  
Eduardo Manta ◽  
Rafael Radi ◽  
...  
Keyword(s):  
Phenylalanine Ammonia Lyase ◽  
Aromatic Amino Acids ◽  
Fermentation Medium ◽  
Coumaric Acid ◽  
Content Type ◽  
Benzoylformate Decarboxylase ◽  
Feeding Experiments ◽  
Tyrosine Ammonia Lyase ◽  
Metabolic Reactions ◽  
Level 2

ABSTRACT Benzenoid-derived metabolites act as precursors for a wide variety of products involved in essential metabolic roles in eukaryotic cells. They are synthesized in plants and some fungi through the phenylalanine ammonia lyase (PAL) and tyrosine ammonia lyase (TAL) pathways. Ascomycete yeasts and animals both lack the capacity for PAL/TAL pathways, and metabolic reactions leading to benzenoid synthesis in these organisms have remained incompletely known for decades. Here, we show genomic, transcriptomic, and metabolomic evidence that yeasts use a mandelate pathway to synthesize benzenoids, with some similarities to pathways used by bacteria. We conducted feeding experiments using a synthetic fermentation medium that contained either 13C-phenylalanine or 13C-tyrosine, and, using methylbenzoylphosphonate (MBP) to inhibit benzoylformate decarboxylase, we were able to accumulate intracellular intermediates in the yeast Hanseniaspora vineae. To further confirm this pathway, we tested in separate fermentation experiments three mutants with deletions in the key genes putatively proposed to form benzenoids (Saccharomyces cerevisiae aro10Δ, dld1Δ, and dld2Δ strains). Our results elucidate the mechanism of benzenoid synthesis in yeast through phenylpyruvate linked with the mandelate pathway to produce benzyl alcohol and 4-hydroxybenzaldehyde from the aromatic amino acids phenylalanine and tyrosine, as well as sugars. These results provide an explanation for the origin of the benzoquinone ring, 4-hydroxybenzoate, and suggest that Aro10p has benzoylformate and 4-hydroxybenzoylformate decarboxylase functions in yeast. IMPORTANCE We present here evidence of the existence of the mandelate pathway in yeast for the synthesis of benzenoids. The link between phenylpyruvate- and 4-hydroxyphenlypyruvate-derived compounds with the corresponding synthesis of benzaldehydes through benzoylformate decarboxylation is demonstrated. Hanseniaspora vineae was used in these studies because of its capacity to produce benzenoid derivatives at a level 2 orders of magnitude higher than that produced by Saccharomyces. Contrary to what was hypothesized, neither β-oxidation derivatives nor 4-coumaric acid is an intermediate in the synthesis of yeast benzenoids. Our results might offer an answer to the long-standing question of the origin of 4-hydroxybenzoate for the synthesis of Q10 in humans.

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