Reactive Oxygen Intermediates Mediate a Systemic Signal Network in the Establishment of Plant Immunity

AbstractRecognition of an avirulent pathogen stimulates an oxidative burst generating O2− and H2O2, and these reactive oxygen intermediates (ROIs) cue the induction of defense genes and cell death in the development of a restricted lesion. This localized hypersensitive response (HR) is accompanied by the development of systemic acquired resistance to virulent pathogens. Here we show that inoculation of Arabidopsis leaves with avirulent Pseudomonas syringae induces secondary oxidative bursts in discrete cells in distant tissues, leading to low-frequency systemic micro-HRs. The primary oxidative burst induces these systemic responses, and both the primary burst and the secondary microbursts are required for systemic immunity. Hence, ROIs mediate a reiterative signal network underlying systemic as well as local resistance responses

Observaciones del planetoide (51) Nemusa durante los años 1951-1954

Reaction of AlMe₃ with S­(SiMe₃)­(C₆H₃-2-CH₂NRR′-5-^<i>t</i>Bu) (RR′ = C₅H₁₀ (<b>1a</b>), C₄H₈ (<b>1b</b>), Me₂ (<b>1c</b>)), at ambient temperature, affords the amino adducts [AlMe₃{S­(SiMe₃)­(C₆H₃-2-CH₂NRR′-5-^<i>t</i>Bu)}-<i>κN</i>] (RR′ = C₅H₁₀ (<b>2a</b>), C₄H₈ (<b>2b</b>), Me₂ (<b>2c</b>)), which undergo TMS elimination upon heating to give the monomeric aminoarenethiolate aluminum complexes [AlMe₂{S­(C₆H₃-2-CH₂NRR′-5-^<i>t</i>Bu)-κ²<i>S,N</i>}] (RR′ = C₅H₁₀ (<b>3a</b>), C₄H₈ (<b>3b</b>), Me₂ (<b>3c</b>)). Following the same procedure, treatment of AlCl₂Me and AlCl₃ with <b>1</b> yields analogous aminoarenethiolate aluminum complexes with different degrees of methylation, the chloro methyl and dichloro complexes [AlClMe­{S­(C₆H₃-2-CH₂NRR′-5-^<i>t</i>Bu)-κ²<i>S,N</i>}] (RR′ = C₅H₁₀ (<b>4a</b>), C₄H₈ (<b>4b</b>), Me₂ (<b>4c</b>)) and [AlCl₂{S­(C₆H₃-2-CH₂NRR′-5-^<i>t</i>Bu)}-κ²<i>S,N</i>] (RR′ = C₅H₁₀ (<b>5a</b>), C₄H₈ (<b>5b</b>) Me₂ (<b>5c</b>)), respectively. These complexes have been characterized by multinuclear NMR spectroscopy and elemental analysis. Moreover, the molecular structures of <b>3a</b>,<b>b</b> have been determined by X-ray diffraction methods. Aluminum complexes <b>3</b> have been investigated for the ring-opening polymerization (ROP) of l-lactide, achieving high conversions in relatively short periods of time. The PLAs obtained feature an aminoarenethiolate end functionality, as inferred from MALDI-TOF mass analysis

Synthesis and electrochemical properties of cavitands functionalized with 4,4′-bipyridinium units

Four new brominated resorcinarene cavitand derivatives ( 3– 6 ) and the already known tetrakis(bromomethyl)cavitand 2 have been synthesized, starting from the tetramethylcavitand 1 . These brominated cavitands constitute excellent building blocks for the covalent assembly of new structures containing one ( 8 ), two ( 9 and 10 ), three ( 11 ) and four ( 7 ) monoquaternized bipyridine units attached to the upper rim of the cavitand bowl. The free terminal nitrogens in these structures can be methylated to yield compounds with one to four 4,4′-bipyridinium (viologen) units attached to the cavitand ( 12– 16 ), or treated with monobromocavitand 3 to produce oligomeric structures containing from two to five cavitand units connected by viologen residues ( 17– 21 ). Compounds 8– 16 , 18 and 20 show the electrochemical reactivity anticipated from their reducible units (mono- or diquaternized bipyridines) with no detectable level of electronic communication between them. Surprisingly, compounds 17 , 19 and 21 exhibit more complicated electrochemical behavior, which simplifies and becomes more reversible as the temperature increases. Graphi

Efficacy and safety of valsartan compared with enalapril at different altitudes

To compare the safety, tolerability, and antihypertensive efficacy of valsartan with enalapril at different altitudes. A total of 142 adult Colombian outpatients with mild to moderate essential hypertension were recruited in 3 cities at different altitudes (Bogotá at 2600 m, Medellı́n at 1538 m and Barranquilla at 100 m) and randomized in an open label fashion to receive either valsartan 80 mg once daily or enalapril 20 mg once daily for 8 weeks. Those patients not responding at 4 weeks received additional 1.25 mg indapamide daily during the remaining trial period. The primary efficacy variable was the change in mean sitting diastolic blood pressure (SDBP) from baseline to 4 weeks. Secondary efficacy variables included the change in mean sitting systolic blood pressure (SSBP). The primary criterion for tolerability was the incidence of adverse experiences. Both valsartan and enalapril reduced mean SDBP and SSBP with similar efficacy, independent of altitude. Adverse events irrespective of relationship to trial drug were reported by 12 patients (18.8%) on valsartan and by 15 (23.4%) patients on enalapril. Enalapril was associated with a significantly (P<0.05) higher rate of dry cough and more cases of headache than valsartan. Valsartan 80 mg once daily is as effective as enalapril 20 mg once daily in reducing blood pressure, with tolerability profile at least as good as enalapril’s

Comment on “Oxygen Vacancy Ordering and Electron Localization in CeO₂: Hybrid Functional Study”

Comment on “Oxygen Vacancy Ordering and Electron Localization in CeO₂: Hybrid Functional Study