Lipid mediators in marine diatoms

Aquatic Ecology - Diatoms are eukaryotic microalgae representing one of the major groups in the marine phytoplankton, accounting for up to 40% of annual productivity at sea. They are widely...     

Multiscale modelling of Potts shunt as a potential palliative treatment for suprasystemic idiopathic pulmonary artery hypertension: a paediatric case study

Biomechanics and Modeling in Mechanobiology - Potts shunt (PS) was suggested as palliation for patients with suprasystemic pulmonary arterial hypertension (PAH) and right ventricular (RV) failure....     

River otter and mink occupancy dynamics in riparian systems

Semi-aquatic mammals are dependent upon streams and riparian areas, which are a product of the landscapes they drain. Both local stream morphology and surrounding land use are likely to have important influences on current occupancy of semi-aquatic mammals and potentially affect future geographic distributions. We identified aspects of the riparian system and stream structure at multiple scales that relate to the presence of river otter (Lontra canadensis) and mink (Neovison vison) to better understand how changing landscapes affect occupancy dynamics of these semi-aquatic mammals and to facilitate future monitoring and management. We estimated multi-season occupancy using 103 sites sampled over 6 seasonal sampling periods in southern Illinois, USA (44,526 km²) during 2012–2014. We hypothesized river otter and mink occupancy were related to multiple aspects of landscape and local habitat attributes including land cover, water availability, human disturbance, and stream characteristics. Occupancy of river otter was predicted by large stream size, less developed area near the stream site, and proximity to areas with reintroduced or remnant populations of river otter. Mink were more likely to occupy sites with small streams and decreased water availability near the site. However, top models for both species had low weights and high uncertainty for multiple variables. Habitat-based models may not be the best predictors of occupancy for these carnivores because they are more likely to respond to prey diversity or availability, but landscape changes that decrease natural water availability and increase human disturbance to the stream at the local scale are likely to negatively affect river otter. © 2019 The Authors. The Journal of Wildlife Management published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.     

Structural characterization of the L0 cytoplasmic loop of human multidrug resistance protein 6 (MRP6)

ABCC6 is a member of the C subfamily of ATP-binding cassette transporters whose mutations are correlated to Pseudoxanthoma elasticum, an autosomal recessive, progressive disorder characterized by ectopic mineralization and fragmentation of elastic fibers. Structural studies of the entire protein have been hindered by its large size, membrane association, and domain complexity. Studies previously performed have contributed to shed light on the structure and function of the nucleotide binding domains and of the N-terminal region. Here we report the expression in E. coli of the polypeptide E₂₀₅-G₂₇₉ contained in the cytoplasmic L0 loop. For the first time structural studies in solution were performed. Far-UV CD spectra showed that L0 is structured, assuming predominantly α-helix in TFE solution and turns in phosphate buffer. Fluorescence spectra indicated some flexibility of the regions containing aromatic residues. ¹H NMR spectroscopy identified three helical regions separated by more flexible regions.     

Phosphorylation of NHERF1 S279 and S301 differentially regulates breast cancer cell phenotype and metastatic organotropism

Metastatic cancer cells are highly plastic for the expression of different tumor phenotype hallmarks and organotropism. This plasticity is highly regulated but the dynamics of the signaling processes orchestrating the shift from one cell phenotype and metastatic organ pattern to another are still largely unknown. The scaffolding protein NHERF1 has been shown to regulate the expression of different neoplastic phenotypes through its PDZ domains, which forms the mechanistic basis for metastatic organotropism. This reprogramming activity was postulated to be dependent on its differential phosphorylation patterns. Here, we show that NHERF1 phosphorylation on S279/S301 dictates several tumor phenotypes such as in vivo invasion, NHE1-mediated matrix digestion, growth and vasculogenic mimicry. Remarkably, injecting mice with cells having differential NHERF1 expression and phosphorylation drove a shift from the predominantly lung colonization (WT NHERF1) to predominately bone colonization (double S279A/S301A mutant), indicating that NHERF1 phosphorylation also acts as a signaling switch in metastatic organotropism.     

The effect of high and low dosages of paraoxon in β-naphthoflavone-treated rats

Aliesterases (carboxylesterases) are serine esterases that can serve a protective role for the target acetylcholinesterase (AChE) during organophosphorus insecticide intoxication because the former esterases are alternate phosphorylation sites. The levels of aliesterase activity in liver and plasma and AChE activity in brain regions were investigated after the intravenous administration of paraoxon (P = O) into female rats. The rats were pretreated intraperitoneally with β-naphthoflavone (BNF), which decreases hepatic aliesterase activity following a 3 day in vivo treatment, and/or tri-o-totyl phosphate (TOTP) to inhibit aliesterases. The liver aliesterases were inhibited less by P = O in BNF-treated rats than in control rats, which suggests that either BNF exposure may have resulted in aliesterases that are less sensitive to P = O inhibition or BNF may have altered P = O's availability. The BNF treatment did not seem to alter the degree of inhibition of the brain AChE activity following the low dosage of paraoxon (0.04 mg/kg). However, the brain AChE activity in the P = O/TOTP/BNF-treated rats was lower than that in the P = O/TOTP-treated rats, suggesting that BNF also caused changes in systems affecting the disposition of P = O in addition to the changes in the hepatic aliesterases. At the high dosage of paraoxon (0.12 mg/kg), the AChE and aliesterase activities showed a pattern similar to that of the low dosage. This suggests that the aliesterases, as altered by BNF exposure, even when nearly completely inhibited, did not alter the response of the target enzyme, AChE, and, therefore, the magnitude of the toxic response. © 1997 John Wiley & Sons, Inc. J Biochem Toxicol 11: 263–268, 1997.