Negative regulation of germination-arrest factor production in Pseudomonas fluorescens WH6 by a putative extracytoplasmic function sigma factor.

Pseudomonas fluorescens WH6 secretes a germination-arrest factor (GAF) that we have identified previously as 4-formylaminooxyvinylglycine. GAF irreversibly inhibits germination of the seeds of numerous grassy weeds and selectively inhibits growth of the bacterial plant pathogen Erwinia amylovora. WH6-3, a mutant that has lost the ability to produce GAF, contains a Tn5 insertion in prtR, a gene that has been described previously in some strains of P.

The Pseudomonas aeruginosa antimetabolite L-2-amino-4-methoxy-trans-3-butenoic acid inhibits growth of Erwinia amylovora and acts as a seed germination-arrest factor.

The Pseudomonas aeruginosa antimetabolite L-2-amino-4-methoxy-trans-3-butenoic acid (AMB) shares biological activities with 4-formylaminooxyvinylglycine, a related molecule produced by Pseudomonas fluorescens WH6. We found that culture filtrates of a P. aeruginosa strain overproducing AMB weakly interfered with seed germination of the grassy weed Poa annua and strongly inhibited growth of Erwinia amylovora, the causal agent of the devastating orchard crop disease known as fire blight.

Hybrid polymeric nanoparticles: potential candidate for ophthalmic delivery.

Nanotechnology that deals with submicron particles has the potential to deeply impact ophthalmic delivery owing to its ability to transport incorporated active ingredient/drugs to the different compartments of the eye while protecting them from any external assault. Polymeric nanoparticles, in particular hybrid nanoparticles made up of different biodegradable and biocompatible polymers, has the potential to revolutionize ocular delivery carrier systems by taking advantage of their highly tunable physicochemical properties. Here we report a synthesis method of hybrid nanoparticles made up of chitosan-poly(lactide-co-glycolide) (PLGA, as a building block of the nanocarrier) as a carrier for ophthalmic delivery.

Molecular characterization of AfuFleA, an L-fucose-specific lectin from Aspergillus fumigatus.

Aspergillus fumigatus causes life-threatening infections in immunocompromised patients. We have found that extracts of mycelial mats of A. fumigatus contain a potent hemagglutinin.

Pseudomonas fluorescens SBW25 produces furanomycin, a non-proteinogenic amino acid with selective antimicrobial properties.

Background: Pseudomonas fluorescens SBW25 has been extensively studied because of its plant growth promoting properties and potential as a biocontrol agent. The genome of SBW25 has been sequenced, and among sequenced strains of pseudomonads, SBW25 appears to be most closely related to P. fluorescens WH6.

Development of a quantitative assay amenable for high-throughput screening to target the type II secretion system for new treatments against plant-pathogenic bacteria.

Plant-pathogenic bacteria are the causative agents of diseases in important agricultural crops and ornamental plants. The severe economic burden of these diseases requires seeking new approaches for their control, particularly because phytopathogenic bacteria are often resistant to available treatments. The type II secretion (T2S) system is a key virulence factor used by major groups of phytopathogenic bacteria.

Genetics of germination-arrest factor (GAF) production by Pseudomonas fluorescens WH6: identification of a gene cluster essential for GAF biosynthesis.

The genetic basis of the biosynthesis of the germination-arrest factor (GAF) produced by Pseudomonas fluorescens WH6, and previously identified as 4-formylaminooxyvinylglycine, has been investigated here. In addition to inhibiting the germination of a wide range of grassy weeds, GAF exhibits a selective antimicrobial activity against the bacterial plant pathogen Erwinia amylovora. We utilized the in vitro response of E.

Infections in patients with hematologic neoplasms and hematopoietic stem cell transplantation: neutropenia, humoral, and splenic defects.

Infections are common in patients with hematologic neoplasms and following allogeneic hematopoietic transplantation. Neutropenia and defects in adaptive B-cell-mediated immunity and/or lack of splenic function predispose patients to a host of diverse and often serious infections. It is important to recognize that patients who undergo treatment for hematologic neoplasms may have mixed immune defects, and their vulnerability to infection may continue to change, in part as a reflection of the dynamic developments in the practice of oncology.

4-Formylaminooxyvinylglycine, an herbicidal germination-arrest factor from Pseudomonas rhizosphere bacteria.

A new oxyvinylglycine has been identified as a naturally occurring herbicide that irreversibly arrests germination of the seeds of grassy weeds, such as annual bluegrass (Poa annua), without significantly affecting the growth of established grass seedlings and mature plants or germination of the seeds of broadleaf plant species (dicots). Previously, Pseudomonas fluorescens WH6 and over 20 other rhizosphere bacteria were isolated and selected for their ability to arrest germination of P. annua seeds.

An improved, high-quality draft genome sequence of the Germination-Arrest Factor-producing Pseudomonas fluorescens WH6.

Background: Pseudomonas fluorescens is a genetically and physiologically diverse species of bacteria present in many habitats and in association with plants. This species of bacteria produces a large array of secondary metabolites with potential as natural products. P.

A rat model for choroidal neovascularization using subretinal lipid hydroperoxide injection.

The purpose of this study was to develop and characterize a rat model of choroidal neovascularization (CNV) as occurs in age-related macular degeneration. The lipid hydroperoxide 13(S)-hydroperoxy-9Z,11E-octadecadienoic acid (HpODE) is found in submacular Bruch's membrane in aged humans and has been reported to generate neovascularization in a rabbit model. Three weeks after a single subretinal injection of 30 microg of HpODE, eyes of Sprague-Dawley rats were harvested.

Zymographical techniques for detection of matrix metalloproteinases.

Matrix metalloproteinases (MMPs) are a family of zinc-dependent proteinases associated with extracellular matrix degradation, cellular migration, tissue remodeling, and angiogenesis. The activity of MMPs is regulated by the tissue inhibitors of metalloproteinases (TIMPs). Zymography and reverse zymography are useful to detect MMPs and TIMPs activities from various samples, for example vitreous, retina, plasma, and so on.

From nutraceuticals to pharmaceuticals to nanopharmaceuticals: a case study in angiogenesis modulation during oxidative stress.

This report reviews the potential applications of nanotechnology in various therapeutics and diagnostics areas with special emphasis on key frontiers in angiogenesis modulation using naturally driven drug targets including compounds that modulate oxidative stress and inflammatory pathways for the potential treatment of vascular, cancer, inflammatory, and ocular disorders. Recent advances of the nanotechnology mediated gene delivery are also described in this paper.

Effect of a dihydrobenzofuran derivative on lipid hydroperoxide-induced rabbit corneal neovascularization.

The aim of this study was to investigate the effect of A-3922, a dihydrobenzofuran derivative, on linoleic acid hydroperoxide (LHP)-induced corneal neovascularization (NV) in a rabbit model. Male New Zealand rabbits received intraperitoneal (i.p.

Effect of lipid-hydroperoxide-induced oxidative stress on vitamin E, ascorbate and glutathione in the rabbit retina.

Background: It is possible that oxidative stress causes several retinal diseases. However, the natural biogenic role of antioxidants in the retina is not clear.

Purpose: This study investigates the change in concentration of vitamin E (VE), ascorbate and glutathione (GSH) in the retina following vitreous injection of 600 mug 18:2 linoleic acid hydroperoxide (LHP) in male New Zealand rabbits.

Activation of AP-1 and increased synthesis of MMP-9 in the rabbit retina induced by lipid hydroperoxide.

Purpose: We identified the temporal expression of activator protein-1 (AP-1) and matrix metalloproteinases (MMPs) after linoleic acid hydroperoxide (LHP) induction of retinal neovascularization.

Methods: After injection of LHP into the vitreous of rabbits, samples were collected for AP-1 binding activity and mRNA for MMP-9 and MMPs activity. AP-1 binding activity was measured by electrophoretic mobility shift assay.

Protective effect of polyethylene glycol-superoxide dismutase on leukocyte dynamics in rat retinal microcirculation under lipid hydroperoxide-induced oxidative stress.

The levels of lipid hydroperoxide (LHPs) in vitreous are elevated in a variety of retinal disorders. Recently, we have shown that increased levels of LHPs in the vitreous enhanced leukocyte-endothelium interaction in the retina, which should contribute to the initial disturbance of the retinal microcirculation. Based upon the previous work, the purpose of the present study was to investigate the effect of polyethylene glycol-superoxide dismutase (PEG-SOD), one of the important enzyme antioxidants, on leukocyte-endothelial interaction in the retinal microcirculation under LHP-induced oxidative stress.

Lipid hydroperoxide-induced tumor necrosis factor (TNF)-alpha, vascular endothelial growth factor and neovascularization in the rabbit cornea: effect of TNF inhibition.

Lipid hydroperoxides (LHP) at high concentrations are cytotoxic, but at sublethal concentration, they induce synthesis of cytokine vascular growth factors. Intracorneal injections of 30 μg LHP placed 5 mm from the superior limbus stimulated early vasodilation of limbal vasculature and a rapidly developing, sustained neovascularization. Under these conditions, vessels grew at the rate of 0.

Fungal cell wall septation and cytokinesis are inhibited by bleomycins.

When the essential and distinctive cell walls of either pathogenic or nonpathogenic fungi break, cytoplasmic membranes rupture and fungi die. This fungicidal activity was discovered previously on nonproliferating Saccharomyces cerevisiae cells treated briefly with the oxidative tool and anticancer drug family of bleomycins. The present studies investigated effects of bleomycin on growing fungal organisms.