48 research outputs found
Quantification and light micrographs demonstrating the simulative effect of dATP on adherence of <i>A. baumannii</i> to human bronchial epithelial NCI-H292 cells.
<p>A, Number of <i>A. baumannii</i> cells adhered to the monolayer of 100 human bronchial epithelial NCI-H292 cells after 1 hour incubation at 37°C with 5% (v/v) CO<sub>2</sub> in the RPMI 1640 medium with different treatments: Control (no treatment); dATP (medium supplemented 400 µM of dATP; Apyrase (medium supplemented with 200 mU/ml of Apyrase; Damage (around 5% of a monolayer of the epithelial cells was damaged); and a combination of two treatments. Three independent experiments were performed for each treatment and standard deviations of three treatments were included. B, Representative light micrograph of <i>A. baumannii</i> cells adhered to the epithelial cells after incubation in the RPMI 1640 medium without supplementing dATP;and, C, with supplementing dATP. (Objective 60×).</p
Quantification of biofilms developed by <i>E. coli</i> K-12 in 10% LB supplemented with different reagents: no addition of any reagents (control); DNase I (40 U/ml); Apyrase (200 mU/ml); dATP (400 µM); dATP (400 µM) and DNase I (40 U/ml); or dATP (400 µM) and Apyrase (200 mU/ml).
<p>Biofilms were examined after 16 hrs incubation after inoculation at 30°C in a 96-well microtiter plate. Crystal violet staining assay was used to determine biofilm biomass.</p
Confocal laser scanning micrographs of biofilms developed by <i>E. coli</i> K-12 in 10% LB broth with different reagents.
<p>A, control, without any additional reagents; B, with 400 µM of dATP;, C, with 40 U/ml of DNase I; and D, with 200 mU/ml of Apyrase. Biofilms were examined after 16 hrs incubation after inoculation at 30°C in a 96-well microtiter plate. Bacterial cells were stained with Bacterial LIVE/DEAD staining dyes and viable cells shown green and dead or membrane damaged cells shown red in the images.</p
Growth of <i>E.coli</i> K-12 in suspensions and biofilms and eDNA released in suspended cultures and biofilm matrix in 10% LB supplemented with or without dATP (400 µM).
<p>A, growth of <i>E.coli</i> K-12 in suspensions and biofilms; B, eDNA in cultures and biofilm matrix. eDNA was extracted using the method we developed (see the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0013355#s4" target="_blank">Materials and Methods</a> section) and quantified using the PicoGreen dsDNA Quantitation Kit (Molecular Probes, Invitrogen). P values from statistical analysis of three independent experiments were shown in the graph. Student T-test was used for statistic analysis.</p
Family of Defect-Dicubane Ni<sub>4</sub>Ln<sub>2</sub> (Ln = Gd, Tb, Dy, Ho) and Ni<sub>4</sub>Y<sub>2</sub> Complexes: Rare Tb(III) and Ho(III) Examples Showing SMM Behavior
Reactions
of Ln<sup>III</sup> perchlorate (Ln = Gd, Tb, Dy, and
Ho), NiCl<sub>2</sub>·6H<sub>2</sub>O, and a polydentate Schiff
base resulted in the assembly of novel isostructural hexanuclear Ni<sub>4</sub>Ln<sub>2</sub> complexes [Ln = Gd (<b>1</b>), Tb (<b>2</b>), Dy (<b>3</b>), Ho (<b>4</b>)] with an unprecedented
3d–4f metal topology consisting of two defect-dicubane units.
The corresponding Ni<sub>4</sub>Y<sub>2</sub> (<b>5</b>) complex
containing diamagnetic Y<sup>III</sup> atoms was also isolated to
assist the magnetic studies. Interestingly, complexes <b>2</b> and <b>3</b> exhibit SMM characteristics and <b>4</b> shows slow relaxation of the magnetization. The absence of frequency-dependent
in-phase and out-of-phase signals for the Ni–Y species suggests
that the Ln ions’ contribution to the slow relaxation must
be effectual as previously observed in other Ni–Dy samples.
However, the observation of <i>χ″</i> signals
with zero dc field for the Ni–Tb and Ni–Ho derivatives
is notable. Indeed, this is the first time that such a behavior is
observed in the Ni–Tb and Ni–Ho complexes
Enhancement of Magnetocaloric Effect through Fixation of Carbon Dioxide: Molecular Assembly from Ln<sub>4</sub> to Ln<sub>4</sub> Cluster Pairs
A series <b>1.Ln</b> of tetranuclear lanthanide clusters [Ln<sub>4</sub>(μ<sub>4</sub>-O)ÂL<sub>2</sub>Â(PhCOO)<sub>6</sub>]·solvent (Ln
= Gd (<b>1.Gd</b>), Dy (<b>1.Dy</b>), Ho (<b>1.Ho</b>)) and octanuclear lanthanide Ln<sub>4</sub> cluster pairs <b>2.Ln</b> [Ln<sub>8</sub>(μ<sub>3</sub>–OH)<sub>4</sub>(CO<sub>3</sub>)<sub>2</sub>L<sub>4</sub>Â(PhCOO)<sub>8</sub>]·solvent (Ln = Gd (<b>2.Gd</b>), Dy (<b>2.Dy</b>), Tb (<b>2.Tb</b>)) were assembled by using a bi-Schiff-based
ligand H<sub>2</sub>L and characterized structurally and magnetically.
Interestingly, the octanuclear Ln<sub>4</sub> cluster pairs <b>2.Ln</b> are proposed to be assembled from the tetranuclear clusters <b>1.Ln</b> through the uptake of CO<sub>2</sub> from air in a more
basic media. X-ray structural analyses approved the possible evolution
mechanism. Magnetic studies reveal the coexistence of ferro- and anti-ferromagnetic
interaction in <b>1.Gd</b> and <b>2.Gd</b> by simulating
the direct-current magnetic susceptibility and indicate the CO<sub>3</sub><sup>2–</sup> bridges produce weak ferromagnetic interaction
in <b>2.Gd</b> rather than anti-ferromagnetic interaction by
benzoate bridges in <b>1.Gd</b>. The magnitude of the magnetocaloric
effect has been examined and shows that complex <b>2.Gd</b> exhibits
larger magnetocaloric effect than <b>1.Gd</b>, which could be
probably ascribed to the weak ferromagnetic interaction produced by
the CO<sub>3</sub><sup>2–</sup> bridges
Enhancement of Magnetocaloric Effect through Fixation of Carbon Dioxide: Molecular Assembly from Ln<sub>4</sub> to Ln<sub>4</sub> Cluster Pairs
A series <b>1.Ln</b> of tetranuclear lanthanide clusters [Ln<sub>4</sub>(μ<sub>4</sub>-O)ÂL<sub>2</sub>Â(PhCOO)<sub>6</sub>]·solvent (Ln
= Gd (<b>1.Gd</b>), Dy (<b>1.Dy</b>), Ho (<b>1.Ho</b>)) and octanuclear lanthanide Ln<sub>4</sub> cluster pairs <b>2.Ln</b> [Ln<sub>8</sub>(μ<sub>3</sub>–OH)<sub>4</sub>(CO<sub>3</sub>)<sub>2</sub>L<sub>4</sub>Â(PhCOO)<sub>8</sub>]·solvent (Ln = Gd (<b>2.Gd</b>), Dy (<b>2.Dy</b>), Tb (<b>2.Tb</b>)) were assembled by using a bi-Schiff-based
ligand H<sub>2</sub>L and characterized structurally and magnetically.
Interestingly, the octanuclear Ln<sub>4</sub> cluster pairs <b>2.Ln</b> are proposed to be assembled from the tetranuclear clusters <b>1.Ln</b> through the uptake of CO<sub>2</sub> from air in a more
basic media. X-ray structural analyses approved the possible evolution
mechanism. Magnetic studies reveal the coexistence of ferro- and anti-ferromagnetic
interaction in <b>1.Gd</b> and <b>2.Gd</b> by simulating
the direct-current magnetic susceptibility and indicate the CO<sub>3</sub><sup>2–</sup> bridges produce weak ferromagnetic interaction
in <b>2.Gd</b> rather than anti-ferromagnetic interaction by
benzoate bridges in <b>1.Gd</b>. The magnitude of the magnetocaloric
effect has been examined and shows that complex <b>2.Gd</b> exhibits
larger magnetocaloric effect than <b>1.Gd</b>, which could be
probably ascribed to the weak ferromagnetic interaction produced by
the CO<sub>3</sub><sup>2–</sup> bridges
Total synthesis and herbicidal activity of natural rubrolides C, E and F
Rubrolides are natural butyrolactones isolated from the tunicate Ritterella rubra, shows antibacterial, antiviral and plant photosynthesis inhibitory activities. In this study, a facile total synthetic method for preparing the rubrolides from benzaldehyde by a Darzens reaction, aldol reaction and vinylogous aldol condensation in five steps is presented. Three natural rubrolides (E, C and F) were synthesised in the total yields of 25–40%. The bioassay results indicate that rubrolides E, C and F exhibit some herbicidal inhibitory effect against rapeseed, in particular, rubrolide F shows the best herbicidal activities against rapeseed root with the growth inhibitory rate of 72.8%. At greenhouse treatment concentrations of 100 and 500 mg/L, rubrolide F show a positive dose–toxicity correlation towards abutilon plants. Collectively, facile total Synthesis strategy provided the base for further bioactivities study of rubrolides family. Rubrolide F may be act as inhibitor of photosynthesis, and this could be lead structure of new herbicide.</p
Anions Influence the Relaxation Dynamics of Mono‑μ<sub>3</sub>‑OH-Capped Triangular Dysprosium Aggregates
A family of four Dy<sub>3</sub> triangular
circular helicates, namely, [Dy<sub>3</sub>(HL)<sub>3</sub>(μ<sub>3</sub>-OH)Â(CH<sub>3</sub>OH)<sub>2</sub>(H<sub>2</sub>O)<sub>4</sub>]ÂCl<sub>1.5</sub>(OH)<sub>0.5</sub>·0.5H<sub>2</sub>O (<b>1</b>), [Dy<sub>3</sub>(HL)<sub>3</sub>(μ<sub>3</sub>-OH)Â(CH<sub>3</sub>OH)<sub>3</sub>(H<sub>2</sub>O)<sub>2</sub>Cl]ÂCl·CH<sub>3</sub>OH (<b>2</b>), [Dy<sub>3</sub>(HL)<sub>3</sub>(μ<sub>3</sub>-OH)Â(CH<sub>3</sub>OH)<sub>3</sub>(H<sub>2</sub>O)<sub>2</sub>(NO<sub>3</sub>)]Â(NO<sub>3</sub>) (<b>3</b>), and [Dy<sub>3</sub>(HL)<sub>3</sub>(μ<sub>3</sub>-OH)Â(CH<sub>3</sub>OH)<sub>4</sub>(ClO<sub>4</sub>)]Â(ClO<sub>4</sub>) (<b>4</b>), were assembled
by the reaction of a new acylhydrazone ligand H<sub>3</sub>L [(3-hydroxy)-<i>N</i>′-((8-hydroxyquinolin-2-yl)Âmethylene)Âpicolinohydrazide]
with different dysprosiumÂ(III) salts. These compounds represent the
first examples of μ-O<sub>acylhydrazone</sub>-bridged triangular
Dy<sub>3</sub> SMMs reported to date. Alternating-current magnetic
susceptibility measurements revealed that compounds <b>1</b> and <b>2</b> show typical SMM behavior with the occurrence
of multiple relaxation processes, whereas frequency-dependent relaxation
signals without χ″ peaks were observed in <b>3</b> and <b>4</b> under zero dc field. Such distinct dynamic behaviors
are attributed to the different sizes of the terminal coordination
solvent/anions (H<sub>2</sub>O, Cl<sup>–</sup>, NO<sub>3</sub><sup>–</sup>, and ClO<sub>4</sub><sup>–</sup> for <b>1</b>–<b>4</b>, respectively) at the Dy<sub>3</sub> site. Here, similar deviations from the ideal monocapped square-antiprismatic
(<i>C</i><sub>4<i>v</i></sub>) geometry defined
by SHAPE software were observed around local Dy centers in <b>1</b> and <b>2</b>, whereas the situation was completely different
in <b>3</b> and <b>4</b> as a result of the presence of
relatively large anions in the limited space defined by three intercrossing
rigid hydrazone ligands
Anions Influence the Relaxation Dynamics of Mono‑μ<sub>3</sub>‑OH-Capped Triangular Dysprosium Aggregates
A family of four Dy<sub>3</sub> triangular
circular helicates, namely, [Dy<sub>3</sub>(HL)<sub>3</sub>(μ<sub>3</sub>-OH)Â(CH<sub>3</sub>OH)<sub>2</sub>(H<sub>2</sub>O)<sub>4</sub>]ÂCl<sub>1.5</sub>(OH)<sub>0.5</sub>·0.5H<sub>2</sub>O (<b>1</b>), [Dy<sub>3</sub>(HL)<sub>3</sub>(μ<sub>3</sub>-OH)Â(CH<sub>3</sub>OH)<sub>3</sub>(H<sub>2</sub>O)<sub>2</sub>Cl]ÂCl·CH<sub>3</sub>OH (<b>2</b>), [Dy<sub>3</sub>(HL)<sub>3</sub>(μ<sub>3</sub>-OH)Â(CH<sub>3</sub>OH)<sub>3</sub>(H<sub>2</sub>O)<sub>2</sub>(NO<sub>3</sub>)]Â(NO<sub>3</sub>) (<b>3</b>), and [Dy<sub>3</sub>(HL)<sub>3</sub>(μ<sub>3</sub>-OH)Â(CH<sub>3</sub>OH)<sub>4</sub>(ClO<sub>4</sub>)]Â(ClO<sub>4</sub>) (<b>4</b>), were assembled
by the reaction of a new acylhydrazone ligand H<sub>3</sub>L [(3-hydroxy)-<i>N</i>′-((8-hydroxyquinolin-2-yl)Âmethylene)Âpicolinohydrazide]
with different dysprosiumÂ(III) salts. These compounds represent the
first examples of μ-O<sub>acylhydrazone</sub>-bridged triangular
Dy<sub>3</sub> SMMs reported to date. Alternating-current magnetic
susceptibility measurements revealed that compounds <b>1</b> and <b>2</b> show typical SMM behavior with the occurrence
of multiple relaxation processes, whereas frequency-dependent relaxation
signals without χ″ peaks were observed in <b>3</b> and <b>4</b> under zero dc field. Such distinct dynamic behaviors
are attributed to the different sizes of the terminal coordination
solvent/anions (H<sub>2</sub>O, Cl<sup>–</sup>, NO<sub>3</sub><sup>–</sup>, and ClO<sub>4</sub><sup>–</sup> for <b>1</b>–<b>4</b>, respectively) at the Dy<sub>3</sub> site. Here, similar deviations from the ideal monocapped square-antiprismatic
(<i>C</i><sub>4<i>v</i></sub>) geometry defined
by SHAPE software were observed around local Dy centers in <b>1</b> and <b>2</b>, whereas the situation was completely different
in <b>3</b> and <b>4</b> as a result of the presence of
relatively large anions in the limited space defined by three intercrossing
rigid hydrazone ligands