Nomimicins B–D, new tetronate-class polyketides from a marine-derived actinomycete of the genus Actinomadura

Three new tetronate-class polyketides, nomimicins B, C, and D, along with nomimicin, hereafter named nomimicin A, were isolated from the culture extract of Actinomadura sp. AKA43 collected from floating particles in the deep-sea water of Sagami Bay, Japan. The structures of nomimicins B, C, and D were elucidated through the interpretation of NMR and MS analytical data, and the absolute configuration was determined by combination of NOESY/ROESY and ECD analyses. Nomimicins B, C, and D showed antimicrobial activity against Gram-positive bacteria, Kocuria rhizophila and Bacillus subtilis, with MIC values in the range of 6.5 to 12.5 μg/mL. Nomimicins B and C also displayed cytotoxicity against P388 murine leukemia cells with IC50 values of 33 and 89 μM, respectively.

Effect of Floating Metallic Particles in Pre-Breakdown and Breakdown Characteristics of Oil Transformer under DC Voltage

Contaminants in transformer oil insulation can float when meeting several conditions. Then, the presence of floating contaminants affects the electrical characteristics of oil insulation. Therefore, the pre-breakdown (corona) and breakdown characteristics due to metallic floating particles in transformer oil insulation would be investigated. This test used DC high voltage stress. A 56 Ω resistor was connected to the oscilloscope to detect the corona currents. The camera was used to capture the images of corona light emission. In addition, the electric field between the electrode and particles was simulated. The variables were the particle size, including its shape, and the distance between the particles and the grounded electrode. The experimental results show that the average value of corona inception and breakdown was inversely proportional to the size of floating particles. The peak value of corona current was directly proportional to the particle size. The lowest breakdown voltage was found when the particle was close to the electrode, but they were not in contact.

Impact of Na+ permeation on collective migration of pulmonary arterial endothelial cells

Collective migration of endothelial cells is important for wound healing and angiogenesis. During such migration, each constituent endothelial cell coordinates its magnitude and direction of migration with its neighbors while retaining intercellular adhesion. Ensuring coordination and cohesion involves a variety of intra- and inter-cellular signaling processes. However, the role of permeation of extracellular Na+ in collective cell migration remains unclear. Here, we examined the effect of Na+ permeation in collective migration of pulmonary artery endothelial cell (PAEC) monolayers triggered by either a scratch injury or a barrier removal over 24 hours. In the scratch assay, PAEC monolayers migrated in two approximately linear phases. In the first phase, wound closure started with fast speed which then rapidly reduced within 5 hours after scratching. In the second phase, wound closure maintained at slow and stable speed from 6 to 24 hours. In the absence of extracellular Na+, the wound closure distance was reduced by >50%. Fewer cells at the leading edge protruded prominent lamellipodia. Beside transient gaps, some sustained interendothelial gaps also formed and progressively increased in size over time, and some fused with adjacent gaps. In the absence of both Na+ and scratch injury, PAEC monolayer migrated even more slowly, and interendothelial gaps obviously increased in size towards the end. Pharmacological inhibition of the epithelial Na+ channel (ENaC) using amiloride reduced wound closure distance by 30%. Inhibition of both the ENaC and the Na+/Ca2+ exchanger (NCX) using benzamil further reduced wound closure distance in the second phase and caused accumulation of floating particles in the media. Surprisingly, pharmacological inhibition of the Ca2+ release-activated Ca2+ (CRAC) channel protein 1 (Orai1) using GSK-7975A, the transient receptor potential channel protein 1 and 4 (TRPC1/4) using Pico145, or both Orai1 and TRPC1/4 using combined GSK-7975A and Pico145 treatment did not affect wound closure distance dramatically. Nevertheless, the combined treatment appeared to cause accumulation of floating particles. Note that GSK-7975A also inhibits small inward Ca2+ currents via Orai2 and Orai3 channels, whereas Pico145 also blocks TRPC4, TRPC5, and TRPC1/5 channels. By contrast, gene silence of Orai1 by shRNAs led to a 25% reduction of wound closure in the first 6 hours but had no effect afterwards. However, in the absence of extracellular Na+ or cellular injury, Orai1 did not affect PAEC collective migration. Overall, the data reveal that Na+ permeation into cells contributes to PAEC monolayer collective migration by increasing lamellipodial formation, reducing accumulation of floating particles, and improving intercellular adhesion.

Values and validity of fetal parameters by ultrasound and Doppler as markers of fetal lung maturity

Background In this study, we combined ultrasound and Doppler parameters to conclude the most accurate and applicable method for fetal lung maturity assessment. Thepurpose is to reduce risk of neonatal respiratory distress by assessment of fetal lung maturity through ultrasound and Doppler instead of amniocentesis. Results A total of 120 women were included. The ultrasound examination was performed at a gestational age ranging between 30 and 37 weeks and delivery occurred within 72 h from ultrasound. After birth, 19 fetuses were diagnosed with RDS. The ultrasound parameters assessed for fetal lung maturity showed varying sensitivity and specificity but presence of proximal tibial epiphyses showed the highest sensitivity (91%) and specificity (95%) followed by the presence of distal femoral epiphyses with 90% sensitivity and 84% specificity. The placental grade III maturity showed a sensitivity of 81% and 74% specificity followed by the presence of the amniotic fluid free-floating particles with an 83% sensitivity and 63% specificity, while echogenic fetal thalamus showed 77% and 79% for sensitivity and specificity, respectively, for prediction of fetal lung maturity. By using the fetal biometry, we could report that a BPD between 82.8 and 93.5 mm, AC between 295 and 322 mm, and FL (62.7-72.1 mm) correlated with mature fetal lungs. Regarding Doppler indices, increased resistive index of umbilical artery > 0.69 and of pulmonary artery > 0.78 correlated with neonatal RDS while fetuses with UtA RI values between 0.43 and 0.66 noticed in RDS vs (0.42-0.57) in the non-RDS. MCA RI values are also higher in RDS 0.77–0.88 vs 0.74–0.79 in non-RDS. On the other hand, analysis of colon grading and fetal lung echogenicity in relation to liver showed no significant value in the assessment of fetal lung maturity. Conclusion Ultrasound and Doppler showed good predictive value and accuracy and is considered a valuable non-invasive procedure in assessment of fetal lung maturity. However, no single parameter alone could show a definitive sign