Pseudomonas lipodepsipeptides and fungal cell wall-degrading enzymes act synergistically in biological control.

Pseudomonas syringae pv. syringae strain B359 secreted two main lipodepsipeptides (LDPs), syringomycin E (SRE) and syringopeptin 25A (SP25A), together with at least four types of cell wall-degrading enzymes (CWDEs). In antifungal bioassays, the purified toxins SRE and SP25A interacted synergistically with chitinolytic and glucanolytic enzymes purified from the same bacterial strain or from the biocontrol fungus Trichoderma atroviride strain P1.

Conformations in solution of the fuscopeptins. Phytotoxic metabolites of Pseudomonas fuscovaginae.

Fuscopeptins are phytotoxic amphiphilic lipodepsipeptides containing 19 amino acid residues. They are produced by the plant pathogenic bacterium Pseudomonas fuscovaginae in two forms, A and B, which differ only in the number of methylene groups in the fatty acid chain. Their covalent structure and biological properties have been reported previously.

Conductive properties and gating of channels formed by syringopeptin 25A, a bioactive lipodepsipeptide from Pseudomonas syringae pv. syringae, in planar lipid membranes.

Syringopeptin 25A, a pseudomonad lipodepsipeptide, can form ion channels in planar lipid membranes. Pore conductance is around 40 pS in 0.1 M NaCl.

The interaction of lipodepsipeptide toxins from Pseudomonas syringae pv. syringae with biological and model membranes: a comparison of syringotoxin, syringomycin, and two syringopeptins.

Pseudomonas syringae pv. syringae produces two groups of cyclic lipodepsipeptides (LDPs): the nona-peptides syringomycins, syringostatins, and syringotoxin (ST), and the more complex syringopeptins composed of either 22 or 25 amino acid residues (SP22 and SP25). Both classes of peptides significantly contribute to bacterial pathogenesis and their primary target of action seems to be the plasma membrane.

Solution conformation of the Pseudomonas syringae MSU 16H phytotoxic lipodepsipeptide Pseudomycin A determined by computer simulations using distance geometry and molecular dynamics from NMR data.

Pseudomycin A is a cyclic lipodepsinonapeptide phytotoxin produced by a strain of the plant pathogenic bacterium Pseudomonas syringae. Like other members of this family of bacterial metabolites, it is characterised by a fatty acylated cyclic peptide with mixed chirality and lactonic closure. Several biological activities of Pseudomycin A are lower than those found for some of its congeners, a difference which might depend on the diverse number and distribution of charged residues in the peptide moiety.

Corpeptins, new bioactive lipodepsipeptides from cultures of Pseudomonas corrugata.

The structure of the corpeptins, bioactive lipodepsipeptides produced in culture by Pseudomonas corrugata, the causal agent of tomato pith necrosis, has been determined. The combined use of FAB-mass spectrometry, NMR spectroscopy and chemical procedures has allowed us to assign the following primary structure to the peptide moiety: Dhb-Pro-Ala-Ala-Ala-Val-Val-Dhb-Hse-Val-alle-Dhp-Ala-Ala-Ala-Val-D hb-aThr-Ala-Dab-Ser-Ile with the terminal carboxy group closing a macrocyclic ring on the hydroxy group of the allo-threonine residue. The N-terminus is in turn acylated by 3-hydroxydecanoate in corpeptin A and by cis-3-hydroxy-5-dodecenoate in corpeptin B.

Biological activities of pseudomycin A, a lipodepsinonapeptide from Pseudomonas syringae MSU 16H.

Similarly to other Pseudomonas lipodepsinonapeptides, pseudomycin A inhibits proton extrusion from maize roots, promotes closure of stomata in Vicia faba, necrosis of tobacco leaves, haemolysis of human erythrocytes, affects H(+)-ATPase activity and proton translocation in plasma membrane vesicles, and stimulates succinate respiration in pea mitochondria. In general, the biological activities of pseudomycin A are lower than those of syringomycin-E, the prototype member of this family of bacterial metabolities. This difference might depend on the diverse number and distribution of charged residues in the peptide moiety of these compounds.

Structure of fuscopeptins, phytotoxic metabolites of Pseudomonas fuscovaginae.

The structure of the fuscopeptins, bioactive lipodepsipeptides produced in culture by the gramineae pathogen Pseudomonas fuscovaginae, has been determined. The combined use of FAB mass spectroscopy NMR spectroscopy and chemical and enzymatic procedures allowed one to define a peptide moiety corresponding to Z-Dhb-D-Pro-L-Leu-D-Ala-D-Ala-D-Ala-D-Ala-D-Val-Gly-D-Ala-D-Val-D-Ala-D- Val-Z-Dhb-Da-Thr-L-Ala-L-Dab-D-Dab-L-Phe with the terminal carboxyl group closing a macrocyclic ring on the hydroxyl group of the allothreonine residue. The N-terminus is in turn acylated by 3-hydroxyoctanoate in fuscopeptin A and 3-hydroxydecanoate in fuscopeptin B.

Solution conformation of the Pseudomonas syringae pv. syringae phytotoxic lipodepsipeptide syringopeptin 25-A. Two-dimensional NMR, distance geometry and molecular dynamics.

Syringopeptin 25-A is a phytotoxic amphiphilic lipodepsipeptide containing 25 amino acid residues, produced by some isolates of the plant pathogenic bacterium Pseudomonas syringae pv. syringae. Previous papers have reported its covalent structure and some of its biological properties.

Pseudomonas syringae pv. syringae phytotoxins reversibly inhibit the plasma membrane H(+)-ATPase and disrupt unilamellar liposomes.

The Pseudomonas syringae pv. syringae phytotoxins syringomycin-E and syringopeptins 22-A and 25-A reversibly and noncompetitively inhibit purified H(+)-ATPase solubilized from plasma membrane of maize roots. Moreover, they increase the passive permeability to protons in phosphatidylcholine/phosphatidylethanolamine liposomes.

Saprophytic Pseudomonas syringae strain M1 of wheat produces cyclic lipodepsipeptides.

A saprophytic fluorescent bacterium (strain M1) isolated from wheat was identified as Pseudomonas syringae and shown to produce the cyclic lipodepsipeptides, syringomycin E and syringopeptin SP25A. M1 grew in planta but did not affect germination or cause disease symptoms in wheat. The findings show that the production of these metabolites, generally regarded as plant virulence factors, does not correlate with plant pathogenicity.

The fungal H(+)-ATPase from Neurospora crassa reconstituted with fusicoccin receptors senses fusicoccin signal.

Fusicoccin affects several physiological processes regulated by the plasma membrane H(+)-ATPase in higher plants while other organisms having P-type H(+)-ATPases (e.g., fungi) are fusicoccin-insensitive.

Other lipopeptides.

Several authors' changes should have been included in the response by D. B. Wheeler et al.

Novel bioactive lipodepsipeptides from Pseudomonas syringae: the pseudomycins.

The covalent structure and most of the stereochemistry of the pseudomycins, bioactive metabolites of a transposon-generated mutant of a Pseudomonas syringae wild-type strain proposed for the biological control of Dutch elm disease, have been determined. While two pseudomycins are identical to the known syringopeptins 25-A and 25-B, pseudomycins A, B, C, C' are new lipodepsinonapeptides. For all of these the peptide moiety corresponds to L-Ser-D-Dab-L-Asp-L-Lys-L-Dab-L-aThr-Z-Dhb-L-Asp(3-OH) -L-Thr (4-Cl) with the terminal carboxyl group closing a macrocyclic ring on the OH group of the N-terminal Ser.

Purification and photoaffinity labeling of fusicoccin receptors from maize.

Crude soluble proteins from plasma membranes of maize shoots were purified (following the increase of fusicoccin-binding specificity) by using an original multi-step HPLC procedure. The method, based on a combination of adsorption, ion-exchange and gel-filtration chromatographies, is quick, efficient and does not damage the binding activity. It allows a 5000-fold increase of specific activity; SDS/PAGE of purified fractions shows two doublets that correspond to proteins with apparent molecular masses of 90 kDa and 30 kDa.

Phospholipase A2 affects the activity of fusicoccin receptors.

Biochemical properties of fusicoccin receptors are strongly influenced by the phospholipid environment. In this report we have studied the effect of different exogenous phospholipases on fusicoccin binding ability of both plasma membrane and solubilised receptors. Among the phospholipases tested only phospholipase A2 showed an inhibitory effect on fusicoccin binding.

The spectroscopic properties of the lipodepsipeptide, syringomycin E.

The spectroscopic properties of syringomycin E, an antibiotic lipodepsinonapeptide associated with pathological states in plants, have been investigated by uv absorbance and CD spectroscopies, and by the synthesis of relevant model compounds. Initial studies [E. Vaillo, A.

Some Properties of a Functional Reconstituted Plasmalemma H-ATPase Activated by Fusicoccin.

Fusicoccin was shown to stimulate the ATP-driven, intravesicular acidification of liposomes reconstituted with crude fusicoccin receptors and the H(+)-translocating ATPase, both solubilized from maize (Zea mays L.) plasma membrane. The present paper reports optimal conditions for dual reconstitution and fusicoccin activation as well as the biochemical characterization of the effect of fusicoccin on this system.

Syringopeptins, new phytotoxic lipodepsipeptides of Pseudomonas syringae pv. syringae.

The primary structure of some new lipodepsipeptides named syringopeptins, produced by plant pathogenic strains of Pseudomonas syringae pv. syringae has been determined by a combination of chemical methods, 1H and 13C NMR spectroscopy and FAB mass spectrometry. Two syringomycin-producing strains afforded 3-hydroxydecanoyl-Dhb-Pro-Val-Val-Ala-Ala-Val-Val-Dhb-Ala-Val-Ala- Ala-Dhb-aThr-Ser-Ala-Dhb-Ala-Dab-Dab-Tyr, with Tyr acylating a Thr to form a macrolactone ring, and smaller amounts of the 3-hydroxydodecanoyl homologue.

Binding of the recombinant proteinase inhibitor eglin c from leech Hirudo medicinalis to serine (pro)enzymes: a comparative thermodynamic study.

The binding of the recombinant proteinase inhibitor eglin c from the leech Hirudo medicinalis to serine (pro)enzymes belonging to the chymotrypsin and subtilisin families has been investigated from the thermodynamic viewpoint, between pH 4.5 and 9.5 and from 10 degrees C to 40 degrees C.

Binding of the recombinant proteinase inhibitor eglin c, of the soybean Bowman-Birk proteinase inhibitor and of its chymotrypsin and trypsin inhibiting fragments to Leu-proteinase, the leucine specific serine proteinase from spinach (Spinacia oleracea L.) leaves: thermodynamic study.

The effect of pH and temperature on the apparent association equilibrium constant (Ka) for the binding of the recombinant proteinase inhibitor eglin c (eglin c), of the soybean Bowman-Birk proteinase inhibitor (BBI) and of its chymotrypsin and trypsin inhibiting fragments (F-C and F-T, respectively) to Leu-proteinase, the leucine specific serine proteinase from spinach (Spinacia oleracea L.) leaves, has been investigated. On lowering the pH from 9.

Structure of syringotoxin, a bioactive metabolite of Pseudomonas syringae pv. syringae.

The covalent structure of syringotoxin, a bioactive metabolite of Pseudomonas syringae pv. syringae isolates, pathogenic on various species of citrus trees, has been deduced from 1D and 2D 1H- and 13C-NMR spectra combined with extensive FAB-MS data and results of some chemical reactions. Similarly to syringomicins and syringostatins, produced by other plant pathogenic strains of P.

Fusicoccin: receptors and endogenous ligands.

The first event in the mode of action of the fungal phytotoxin fusicoccin is the binding to specific receptors located at the plasma membrane. They are very likely related to the presence of endogenous compounds able to compete with FC for binding to its receptors. Some biochemical properties of these proteins conform to criteria commonly used for receptors.

Properties of proteoliposomes containing fusicoccin receptors from maize.

We have recently described a fusicoccin (FC)-sensitive system reconstituted by inserting into liposomes FC-receptors and H(+)-ATPase-enriched preparations from maize tissues. While the proteoliposomes of maize H(+)-ATPase had been already investigated, those of FC-receptors required a careful characterization before use in the dual system. In particular, the influence of the phospholipid environment on time-course, reversibility, and pH-dependence of the FC-binding reaction has been studied by comparing these properties in microsome-bound, solubilized, and liposome-entrapped receptors.