Impairment of Grapevine Xylem Function by Phaeomoniella chlamydospora Infection Is Due to More than Physical Blockage of Vessels with 'Goo'

Phaeomoniella chlamydospora is a vascular pathogen that colonises the woody xylem tissues of the grapevine. It is associated with the grapevine trunk diseases, esca and Petri disease. Infection is usually accompanied by a dark tarry substance, commonly refered to as ‘black goo’, in some of the xylem vessels. Examination of field grown Verdelho demonstrated that infection reduced xylem function by 16% for each 1% increase in ‘goo’-blocked vessels, indicating that vessel blockage is not solely responsible for loss of xylem function

Prevalence and Classification of Amphistomes in Cattle and Buffaloes

Amphistomes are snail-borne trematodes infect rumens and reticulums capable of causing acute and chronic disease in cattle and buffaloes. A total of 897 of cattle and buffaloes were examined by faecal examinations and by postmortem examinations in Giza and Garbia governourates. The collected Amphistomes were morphologically and histologically classified. We found that the incidence of Amphistomes in totally examined animals was 4.9%. The incidence was higher in the oldest animals(than young), in the spring (than other seasons) and in Garbia (than Giza). But the incidence was the same in males and females. The collected Amphistomes were classified as Paramphistomum microbothrium, Paramphistomum cervi and Carmyerius gergaerius. We concluded that Amphistomes are prevalent among the examined cattle and buffaloes in Giza and Garbia governorates.

Comparison of the Molecular Tests - Single PCR, Nested PCR and Quantitative PCR (SYBR Green and TaqMan) - For Detection of Phaemoniella Chlamidospora During Grapevine Nursery Propagation

Water, callus media and plant material were sampled from commercial nurseries during two propagating seasons: 2003 and 2005. Various methods were tested for their ability to detect Phaeomoniella chlamydospora in the samples. Nested PCR and quantitative PCR were the most sensitive, although further research is required to optimise their use. When molecular techniques were used, all water samples tested positive for P. chlamydospora, indicating that the grapevine propagation process is a potential source of infection

NEW FLAVONOIDS FROM THE AERIAL PARTS OF POLYGONUM EQUISETIFORME SM (POLYGONACEAE)

Objective: The current study was to deal the isolation and identification of secondary metabolites from Polygonum equisetiforme and evaluation of antioxidant activity of its extract.Methods: The methanol-water extract (7:3) of the air-dried aerial parts of Polygonum equisetiforme was fractionated and separated to obtain the isolated compounds by different chromatographic techniques. Structures of these compounds were elucidated by UV and 1Dâ„2D Hâ„ C NMR spectroscopy and compared with the literature data. The crude extract was evaluated for in vitro antioxidant activity using the 2,2 diphenyl dipicryl hydrazine (DPPH) method.Results: Ten secondary metabolites were isolated from Polygonum equisetiforme in this study. Of which three new flavonoids named as 3,5,7,2',5' pentahydroxyflavone 3-O-b-D-glucopyranoside (1), 3,5,7,2',5' pentahydroxyflavone 3-O-b-D-glucopyranoside 8 C-sulphated (2) and quercetin 3-O-β-D-glucucorinde 6''-methyl ester 8-sulphated (3) as well as quercetin 3-O-β-D-glucucorinde methyl ester (4), quercetin 3-O-β-D-glucopyranoside (5), quercetin 7-O-β-D-glucopyranoside (6), quercetin(7), myricetin (8), P-methoxy gallic acid methyl ester (9) and gallic acid (10). The antioxidant potential of P. equisetiforme extract was evaluated by investigating it's total phenolic and flavonoid content and DPPH radical scavenging activity whereby the extract showed significant antioxidant activity (IC50 = 37.45 μg/ml). The total phenolic and flavonoid content was found to be 130.79±5.502 and 45.8±1.63 μg/ml, respectively.Conclusion: Polygonum equisetiforme is a promising medicinal plant, and our study tends to support the therapeutic value of this plant as an antioxidant drug

The Impact of Phaeomoniella chlamydospora Infection on the Grapevine's Physiological Response to Water Stress - Part 2 : Cabernet Sauvignon and Chardonnay

Phaeomoniella chlamydospora is a vascular pathogen that colonises the xylem tissues of the grapevine. It is associated with the diseases, esca and Petri disease, often considered to be ‘stress-related’ diseases. In glasshouse experiments using Cabernet Sauvignon and Chardonnay, stomatal conductance was higher in infected plants, implying that infection interferes with stomatal control. In Cabernet Sauvignon, leaf water potentials were lower in infected plants subjected to water stress, indicating that infection made it more difficult for the vine to get water to the leaf. This was less apparent in Chardonnay. Clearly, infection alters the grapevine response to water stress and some cultivars are affected more than others

The Impact of Phaeomoniella chlamydospora Infection on the Grapevine's Physiological Response to Water Stress - Part 1 : Zinfandel

Phaeomoniella chlamydospora is a vascular pathogen that colonises the xylem tissues of the grapevine. It is associated with Petri disease, which is often considered to be ‘stress-related’. In glasshouse experiments using Zinfandel, stomatal conductance was higher in infected plants, implying that infection interferes with stomatal control. Leaf water potentials were lower in infected plants subjected to water stress, indicating that infection made it more difficult for the vine to get water to the leaf. Clearly, infection alters the grapevine’s physiological response to water stress

Stability of trions in strongly spin-polarized two-dimensional electron gases

Low-temperature magneto-photoluminescence studies of negatively charged excitons (X- trions) are reported for n-type modulation-doped ZnSe/Zn(Cd,Mn)Se quantum wells over a wide range of Fermi energy and spin-splitting. The magnetic composition is chosen such that these magnetic two-dimensional electron gases (2DEGs) are highly spin-polarized even at low magnetic fields, throughout the entire range of electron densities studied (5e10 to 6.5e11 cm^-2). This spin polarization has a pronounced effect on the formation and energy of X-, with the striking result that the trion ionization energy (the energy separating X- from the neutral exciton) follows the temperature- and magnetic field-tunable Fermi energy. The large Zeeman energy destabilizes X- at the nu=1 quantum limit, beyond which a new PL peak appears and persists to 60 Tesla, suggesting the formation of spin-triplet charged excitons.Comment: 5 pages (RevTex), 4 embedded EPS figs. Submitted to PRB-R

Low concentrations of nitric oxide modulate Streptococcus pneumoniae biofilm metabolism and antibiotic tolerance

Streptococcus pneumoniae is one of the key pathogens responsible for otitis media (OM), the most common infection in children and the largest cause of childhood antibiotic prescription. Novel therapeutic strategies that reduce the overall antibiotic consumption due to OM are required because although widespread pneumococcal conjugate immunization has controlled invasive pneumococcal disease, overall OM incidence has not decreased. Biofilm formation represents an important phenotype contributing to the antibiotic tolerance and persistence of S. pneumoniae in chronic or recurrent OM. We investigated the treatment of pneumococcal biofilms with nitric oxide (NO), an endogenous signaling molecule and therapeutic agent that has been demonstrated to trigger biofilm dispersal in other bacterial species. We hypothesised that addition of low concentrations of NO to pneumococcal biofilms would improve antibiotic efficacy and higher concentrations exert direct antibacterial effects. Unlike in many other bacterial species, low concentrations of NO, did not result in S. pneumoniae biofilm dispersal. Instead, treatment of both in vitro biofilms and ex vivo adenoid tissue samples (a reservoir for S. pneumoniae biofilms) with low concentrations of NO enhanced pneumococcal killing when combined with amoxicillin-clavulanic acid, an antibiotic commonly used to treat chronic OM. Quantitative proteomic analysis using iTRAQ (isobaric tag for relative and absolute quantitation) identified 13 proteins that were differentially expressed following low-concentration NO treatment, 85% of which function in metabolism or translation. Treatment with low-concentration NO therefore appears to modulate pneumococcal metabolism and may represent a novel therapeutic approach to reduce antibiotic tolerance in pneumococcal biofilms

Low-Dose Nitric Oxide as Targeted Anti-biofilm Adjunctive Therapy to Treat Chronic Pseudomonas aeruginosa Infection in Cystic Fibrosis

© 2017 The Authors Despite aggressive antibiotic therapy, bronchopulmonary colonization by Pseudomonas aeruginosa causes persistent morbidity and mortality in cystic fibrosis (CF). Chronic P. aeruginosa infection in the CF lung is associated with structured, antibiotic-tolerant bacterial aggregates known as biofilms. We have demonstrated the effects of non-bactericidal, low-dose nitric oxide (NO), a signaling molecule that induces biofilm dispersal, as a novel adjunctive therapy for P. aeruginosa biofilm infection in CF in an ex vivo model and a proof-of-concept double-blind clinical trial. Submicromolar NO concentrations alone caused disruption of biofilms within ex vivo CF sputum and a statistically significant decrease in ex vivo biofilm tolerance to tobramycin and tobramycin combined with ceftazidime. In the 12-patient randomized clinical trial, 10 ppm NO inhalation caused significant reduction in P. aeruginosa biofilm aggregates compared with placebo across 7 days of treatment. Our results suggest a benefit of using low-dose NO as adjunctive therapy to enhance the efficacy of antibiotics used to treat acute P. aeruginosa exacerbations in CF. Strategies to induce the disruption of biofilms have the potential to overcome biofilm-associated antibiotic tolerance in CF and other biofilm-related diseases