Effects of polystyrene nanoplastics on endothelium senescence and its underlying mechanism.

Global plastic use has increased rapidly, and environmental pollution associated with nanoplastics (NPs) has been a growing concern recently. However, the impact and biological mechanism of NPs on the cardiovascular system are not well characterized. This study aimed to assess the possibility that NPs exposure promotes premature endothelial cell (EC) senescence in porcine coronary artery ECs and, if so, to elucidate the underlying mechanism. Treatment of ECs with NPs promoted the acquisition of senescence markers, senescence-associated ß-galactosidase activity, and p53, p21, and p16 protein expression, resulting in the inhibition of proliferation. In addition, NPs impaired endothelium-dependent vasorelaxation associated with decreased endothelial nitric oxide synthase (eNOS) expression. NPs enhanced reactive oxygen species formation in ECs, and increased oxidative stress levels were associated with the induction of NADPH oxidases expression, followed by the subsequent downregulation of Sirt1 expression. The characteristics of EC senescence and dysfunction caused by NPs are prevented by an antioxidant (N-acetylcysteine), an NADPH oxidase inhibitor (apocynin), and a Sirt1 activator (resveratrol). These findings indicate that NPs induced premature EC senescence, at least in part, through the redox-sensitive eNOS/Sirt1 signaling pathway. This study suggested the effects and underlying mechanism of NPs on the cardiovascular system, which may provide pharmacological targets to prevent NPs-associated cardiovascular diseases.

Structural characterization of the full-length response regulator spr1814 in complex with a phosphate analogue reveals a novel conformational plasticity of the linker region.

Spr1814 of Streptococcus pneumoniae is a response regulator (RR) that belongs to the NarL/FixJ subfamily and has a four-helix helix-turn-helix DNA-binding domain. Here, the X-ray crystal structure of the full-length spr1814 in complex with a phosphate analogue beryllium fluoride (BeF3(-)) was determined at 2.0 Å. This allows for a structural comparison with the previously reported full-length unphosphorylated spr1814. The phosphorylation of conserved aspartic acid residue of N-terminal receiver domain triggers a structural perturbation at the α4-ß5-α5 interface, leading to the domain reorganization of spr1814, and this is achieved by a rotational change in the C-terminal DNA-binding domain.

Expression, purification and preliminary X-ray crystallographic analysis of nitroalkane oxidase (NAO) from Pseudomonas aeruginosa.

Nitroalkane oxidase (NAO) is a flavin-dependent enzyme which catalyses the oxidation of nitroalkanes to the corresponding aldehydes or ketones, nitrite and hydrogen peroxide. In order to better understand the structure and function of this enzyme, NAO from Pseudomonas aeruginosa was purified and crystallized as a native and a selenomethionine-substituted (SeMet) enzyme. Both crystals diffracted to a resolution of 1.9 Å and belonged to the primitive orthorhombic space group P21, with unit-cell parameters a = 70.06, b = 55.43, c = 87.74 Å, ß = 96.56° for native NAO and a = 69.89, b = 54.83, c = 88.20 Å, ß = 95.79° for SeMet NAO. Assuming the presence of two molecules in the asymmetric unit in both crystals, the Matthews coefficients (VM) for native and SeMet NAO were calculated to be 2.30 and 2.48 ų Da⁻¹, with estimated solvent contents of 46.50 and 50.37%, respectively.

Prospective contralateral eye study to compare 80- and 120-µm flap LASIK using the VisuMax femtosecond laser.

PURPOSE: To compare visual outcomes and flap stability of LASIK with ultrathin 80- and 120-µm flaps created with a VisuMax femtosecond laser (Carl Zeiss Meditec, Jena, Germany) for moderate to high myopia and to evaluate the effect of corneal flap thickness on outcomes. METHODS: In a prospective contralateral eye study, 36 consecutive patients (72 eyes) underwent bilateral LASIK for myopia ranging from -2.00 to -10.00 diopters using the VisuMax femtosecond laser and MEL-80 excimer laser (Carl Zeiss Meditec). One eye of each patient was randomized to have the 80-µm flap and the other to the 120-µm flap created with 200-kHz VisuMax femtosecond laser. Preoperative and postoperative tests included visual acuity, manifest refraction, contrast sensitivity, and flap thickness measured by anterior segment optical coherence tomography. Main outcomes and complications were checked at postoperative 1 week and 1, 3, and 6 months. RESULTS: There were no differences in visual outcome, residual refractive error, or contrast sensitivity between groups during follow-up, except for better uncorrected visual acuity at postoperative 1 day in the 120-µm group. Mean standard deviations of measured flap thickness during follow-up ranged from 3.16 to 3.80 µm in both groups. Opaque bubble layer, a unique complication in femtosecond LASIK, was more frequent in the 80-µm group (7 of 36: 19%) than in the 120-µm flap group (3 of 36: 8%) without a statistically significant difference (P = .301) and was related to thicker central cornea and steeper keratometric value, although it did not influence clinical results. Comparison of the intended versus achieved correction showed no significant differences between groups. CONCLUSIONS: LASIK using the VisuMax femtosecond laser supplied good clinical results and flap reproducibility in both the 80- and 120-µm flap groups. Patients with relatively thin cornea may benefit from 80-µm flap LASIK.

Crystallization and preliminary X-ray crystallographic studies of a new class of enoyl-(acyl-carrier protein) reductase, FabV, from Vibrio fischeri.

Enoyl-(acyl-carrier protein) reductase (ENR) catalyzes the last step of the fatty-acid elongation cycle of the bacterial fatty-acid biosynthesis (FAS II) pathway. Recently, a new class of ENR has been identified from Vibrio cholerae and was named FabV. In order to understand the molecular mechanism of the new class of ENR at the structural level, FabV from V. fischeri was overexpressed, purified and crystallized. Diffraction data were collected to 2.7 Å resolution from a native crystal. The crystal belonged to the orthorhombic space group P2(1)2(1)2, with unit-cell parameters a = 123.53, b = 164.14, c = 97.07 Å. The presence of four molecules of FabV in the asymmetric unit gave a V(M) value of 2.81 Å(3) Da(-1), with a corresponding solvent content of 54.5%.

Crystallization and preliminary X-ray crystallographic studies of enoyl-acyl carrier protein reductase (FabI) from Psuedomonas aeruginosa.

During fatty-acid biosynthesis, enoyl-acyl carrier protein (enoyl-ACP) reductase catalyzes the reduction of trans-2-enoyl-ACP to fully saturated acyl-ACP via the ubiquitous fatty-acid synthase system. NADH-dependent enoyl-ACP reductase (FabI) from Pseudomonas aeruginosa has been purified and crystallized as an apoenzyme and in a complex form with NADH and triclosan. Triclosan is an inhibitor of FabI and forms a stable ternary complex in the presence of NADH. The crystals of native and complexed FabI diffracted to resolutions of 2.6 and 1.8 Å, respectively. The crystals both belonged to space group P2(1), with unit-cell parameters a = 117.32, b = 155.844, c = 129.448 Å, ß = 111.061° for the native enzyme and a = 64.784, b = 107.573, c = 73.517 Å, ß = 116.162° for the complex. Preliminary molecular replacement further confirmed the presence of four tetramers of native FabI and one tetramer of the complex in the asymmetric unit, corresponding to Matthews coefficients (V(M)) of 2.46 and 2.05 Å(3) Da(-1) and solvent contents of 50.1 and 40.1%, respectively.

Reproducibility of LASIK flap thickness using the zeiss femtosecond laser measured postoperatively by optical coherence tomography.

PURPOSE: To evaluate LASIK flap reproducibility and uniformity created with a femtosecond laser using anterior segment optical coherence tomography (OCT). METHODS: A prospective study of 87 consecutive eyes of 44 patients who had flaps created with the 200 kHz VisuMax femtosecond laser (Carl Zeiss Meditec) were included for flap thickness evaluation. All eyes were divided into two groups according to the intended flap thickness (110 µm or 120 µm) and the flap thickness was measured using anterior segment OCT (Visante, Carl Zeiss Meditec) at 1 week and 1 month postoperative. Flap thickness was measured at the flap center, 1.5-mm and 3.0-mm zone from the flap center, and along the 45° (including 225°) and 135° (including 315°) meridian (a total of 10 points). RESULTS: The mean achieved flap thickness was 112.8±3.95 µm (range: 108.9 to 116.4 µm) and 112.3±3.84 µm (range: 109.6 to 115.1 µm) at 1 week and 1 month postoperative, respectively, in the 110 µm group, and 122.5±3.98 µm (range: 117.3 to 128.5 µm) and 122.2±3.93 µm (range: 115.8 to 129.0 µm), respectively, in the 120 µm group. The mean range of flap thickness at 1 month postoperative was 6.29±0.76 µm and 7.37±2.98 µm in the 110 and 120 µm groups, respectively. CONCLUSIONS: Flap creation with the VisuMax femtosecond laser was found to be highly predictable with good reproducibility and uniform morphology when measured with anterior segment OCT.