We present an ab initio molecular dynamics simulation of the aqueous liquid-vapor interface. Having successfully stabilized a region of bulk water in the center of a water slab, we were able to ...reproduce and further quantify the experimentally observed abundance of surface "acceptor-only" (19%) and "single-donor" (66%) moieties as well as substantial surface relaxation approaching the liquid-vapor interface. Examination of the orientational dynamics points to a faster relaxation in the interfacial region. Furthermore, the average value of the dipole decreases and the average value of the highest occupied molecular orbital for each water molecule increases approaching the liquid-vapor interface. Our results support the idea that the surface contains, on average, far more reactive states than the bulk.
This study is to investigate the molecular mechanism of radiation-enhanced cell invasiveness of hepatocellular carcinoma (HCC) correlating with clinical patients undergoing radiotherapy and ...subsequently developing metastasis. Three HCC cell lines (HepG2, Hep3B and Huh7) and normal hepatocyte cell line (CL-48) were irradiated with different doses. The effect of radiation on cell invasiveness was determined using the Boyden chamber assay. Radiation-enhanced invasion capability was evident in HCC cells but not in normal hepatocytes. Invasion was observed in gelatin-coated but not fibronectin-coated or type I collagen-coated membranes. Radiation upregulated matrix metalloproteinase-9 (MMP-9) mRNA level, MMP-9 protein level and MMP-9 activity. MMP-9 antisense oligonucleotides inhibited radiation-induced MMP-9 expression and thereby significantly inhibited radiation-induced HCC invasion. Furthermore, phosphatidylinositol 3-kinase (PI3K)/Akt chemical inhibitors LY294002 and wortmannin suppressed radiation-induced MMP-9 mRNA expression. Transient transfection with dominant-negative Akt plasmid also showed that the PI3K/Akt-signaling pathway was involved in this radiation-induced MMP-9 expression. Moreover, nuclear factor-κB (NF-κB) decoy oligodeoxynucleotide suppressed radiation enhanced MMP-9 promoter activity completely. PI3K/Akt chemical inhibitors inhibited radiation-induced NF-κB-driven luciferase promoter activity. Taken together, our results indicated that sublethal dose of radiation could enhance HCC cell invasiveness by MMP-9 expression through the PI3K/Akt/NF-κB signal transduction pathway.
Amyotrophic Lateral Sclerosis (ALS) is a devastative neurodegenerative disease characterized by selective loss of motoneurons. While several breakthroughs have been made in identifying ALS genetic ...defects, the detailed molecular mechanisms are still unclear. These genetic defects involve in numerous biological processes, which converge to a common destiny: motoneuron degeneration. In addition, the common comorbid Frontotemporal Dementia (FTD) further complicates the investigation of ALS etiology. In this study, we aimed to explore the protein-protein interaction network built on known ALS-causative genes to identify essential proteins and common downstream proteins between classical ALS and ALS+FTD (classical ALS + ALS/FTD) groups. The results suggest that classical ALS and ALS+FTD share similar essential protein set (VCP, FUS, TDP-43 and hnRNPA1) but have distinctive functional enrichment profiles. Thus, disruptions to these essential proteins might cause motoneuron susceptible to cellular stresses and eventually vulnerable to proteinopathies. Moreover, we identified a common downstream protein, ubiquitin-C, extensively interconnected with ALS-causative proteins (22 out of 24) which was not linked to ALS previously. Our in silico approach provides the computational background for identifying ALS therapeutic targets, and points out the potential downstream common ground of ALS-causative mutations.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
AIMS: To investigate whether Photobacterium damselae subsp. piscicida (Phdp) can sense and directly respond to the presence of cationic antimicrobial peptides (AMPs). METHODS AND RESULTS: We ...performed proteomic methodologies to investigate the responsive proteins of Phdp on exposure to AMP Q6. Proteins significantly altered were analysed by two‐dimensional gel electrophoresis (2‐DE) and LC‐ESI‐Q‐TOF MS/MS, thus resulting in five outer membrane proteins (OMPs), seven inner membrane proteins (IMPs) and 17 cytoplasmic proteins (CPs) identified. Quantitative real‐time PCR was also applied to monitor the mRNA expression level of these target proteins. CONCLUSIONS: COG analysis revealed that upon exposure to AMP Q6, the majority of the upregulated proteins were involved in signal transduction mechanism, carbohydrate transport and metabolism, post‐translational modification, protein turnover and chaperones, while the downregulated proteins were mainly related to energy production and conversion. Among them, phage‐shock‐protein A (PspA)‐related stress response system was considered to play a crucial role. SIGNIFICANCE AND IMPACT OF THE STUDY: To the best of our knowledge, this is the first report elucidating Phdp AMP‐response mechanism using proteomics approach. AMP‐responsive proteins identified in this study could serve as attractive targets for developing more effective antimicrobial agents against Phdp and other marine bacterial pathogens.
Glucocerebrosidase (GCase), encoded by the GBA gene, degrades the ubiquitous glycosphingolipid glucosylceramide. Inherited GCase deficiency causes Gaucher disease (GD). In addition, carriers of an ...abnormal GBA allele are at increased risk for Parkinson's disease. GCase undergoes extensive modification of its four N‐glycans en route to and inside the lysosome that is reflected in changes in molecular weight as detected with sodium dodecyl sulfate‐polyacrylamide gel electrophoresis. Fluorescent activity‐based probes (ABPs) that covalently label GCase in reaction‐based manner in vivo and in vitro allow sensitive visualization of GCase molecules. Using these ABPs, we studied the life cycle of GCase in cultured fibroblasts and macrophage‐like RAW264.7 cells. Specific attention was paid to the impact of 4‐(2‐hydroxyethyl)‐1‐piperazineethanesulfonic acid (HEPES) supplementation to bicarbonate‐buffered medium. Here, we report how HEPES‐buffered medium markedly influences processing of GCase, its lysosomal degradation, and the total cellular enzyme level. HEPES‐containing medium was also found to reduce maturation of other lysosomal enzymes (α‐glucosidase and β‐glucuronidase) in cells. The presence of HEPES in bicarbonate containing medium increases GCase activity in GD‐patient derived fibroblasts, illustrating how the supplementation of HEPES complicates the use of cultured cells for diagnosing GD.
Exploitation for trade is one of the biggest threats to many species, especially for marine fishes. Trade regulations should, therefore, be effective in helping conserve marine fish populations. The ...Convention of International Trade in Endangered Species of Wild Fauna and Flora (CITES), one of the few multilateral environmental agreements with enforcement capacity, has embraced a number of marine fishes in recent years. However, the impacts of such measures on wildlife trade have rarely been assessed. We conducted a case study of the dried seahorse (
Hippocampus
spp.) trade in Thailand to understand the trade of these species under CITES regulations. We carried out 203 semi-structured interviews with traders to estimate the economic scale of Thai seahorse trade, and compared perceived changes with official trade datasets. Even though most seahorses were incidentally caught, we estimated that dried seahorses could be worth US$26.5 million per year for Thai fishers. However, the total declared annual export value was only around US$5.5 million, and had decreased to US$1 million in 2013. Considering the economic value of seahorses, the large discrepancy between declared export volumes and catch estimates suggested that trade may be underreported. While official data shows the export volume decreased after the implementation of CITES listing in 2005, our respondents did not report a similar trend. In contrast, the prices of seahorses were reported to be increasing. Our study highlights the economic importance of marine fishes captured as bycatch and the importance of international and domestic management measures for the trade of bycatch species.
Here, we present a measurement of gravitational lensing over 1500deg2 of the Southern sky using SPT-3G temperature data at 95 GHz and 150 GHz taken in 2018. The lensing amplitude relative to a ...fiducial Planck 2018 Lambda cold dark matter ( Λ CDM ) cosmology is found to be 1.020±0.060 , excluding instrumental and astrophysical systematic uncertainties. We conduct extensive systematic and null tests to check the robustness of the lensing measurements, and report a minimum-variance combined lensing power spectrum over angular multipoles of 50<L<2000 , which we use to constrain cosmological models. When analyzed alone and jointly with primary cosmic microwave background (CMB) spectra within the Λ CDM model, our lensing amplitude measurements are consistent with measurements from SPT-SZ, SPTpol, ACT, and Planck. Incorporating loose priors on the baryon density and other parameters including uncertainties on a foreground bias template, we obtain a 1σ constraint on σ8 Ω m 0.25=0.595±0.026 using the SPT-3G 2018 lensing data alone, where σ8 is a common measure of the amplitude of structure today and Ω m is the matter density parameter. Combining SPT-3G 2018 lensing measurements with baryon acoustic oscillation (BAO) data, we derive parameter constraints of σ8=0.810±0.033 , S8≡σ8 ( Ω m /0.3 ) 0.5= 0.836±0.039 , and Hubble constant H0=68.8-1.6+1.3km s -1Mpc-1 . Our preferred S8 value is higher by 1.6 to 1.8σ compared to cosmic shear measurements from DES-Y3, HSC-Y3, and KiDS-1000 at lower redshift and smaller scales. We combine our lensing data with CMB anisotropy measurements from both SPT-3G and Planck to constrain extensions of Λ CDM . Using CMB anisotropy and lensing measurements from SPT-3G only, we provide independent constraints on the spatial curvature of Ω K=0.014-0.026+0.023 (95% C.L.) and the dark energy density of Ω Λ =0.722-0.026+0.031 (68% C.L.). When combining SPT-3G lensing data with SPT-3G CMB anisotropy and BAO data, we find an upper limit on the sum of the neutrino masses of Σmν<0.30eV (95% C.L.). Due to the diferent combination of angular scales and sky area, this lensing analysis provides an independent check on lensing measurements by ACT and Planck.
Artificial selection can provide insights into how insecticide resistance mechanisms evolve in populations. The underlying basis of such phenomena can involve complex interactions of multiple genes, ...and the resolution of this complexity first necessitates confirmation that specific genes are involved in resistance mechanisms. Here, we used a novel approach invoking a constrained RNA sequencing analysis to refine the discovery of specific genes involved in insecticide resistance. Specifically, for gene discovery, an additional constraint was added to the traditional comparisons of susceptible vs. resistant flies by the incorporation of a line in which insecticide susceptibility was ‘recovered’ within a resistant line by the removal of insecticide stress. In our analysis, the criterion for the classification of any gene as related to insecticide resistance was based on evidence for differential expression in the resistant line as compared with both the susceptible and recovered lines. The incorporation of this additional constraint reduced the number of differentially expressed genes putatively involved in resistance to 464, compared with more than 1000 that had been identified previously using this same species. In addition, our analysis identified several key genes involved in metabolic detoxification processes that showed up‐regulated expression. Furthermore, the involvement of acetylcholinesterase, a known target for modification in insecticide resistance, was associated with three key nonsynonymous amino acid substitutions within our data. In conclusion, the incorporation of an additional constraint using a ‘recovered’ line for gene discovery provides a higher degree of confidence in genes identified to be involved in insecticide resistance phenomena.
The nano-sized silica fillers reinforced poly(ether ether ketone) (PEEK) composites were fabricated by means of compression molding technique. The nano-sized silica, measuring 30
nm in size, was ...firstly modified by surface pretreatment with stearic acid. The performances and properties of the resulting PEEK/SiO
2 nanocomposites were examined in terms of tensile loading, hardness, dynamic mechanical analysis (DMA), thermomechanical analysis (TMA), thermogravimetry analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The modified nano-silica was seen to disperse more uniformly than the unmodified counterpart. The XRD patterns of the modified silica reinforced PEEK composites reveal a systematic shift toward higher angles, suggesting the smaller
d-spacing of the PEEK crystallites. The coefficient of thermal expansion (CTE) becomes lowered when the content of the nano-silica increases. Furthermore, the CTE of the modified silica filled PEEK nanocomposites shows the higher CTE values. A logic model is proposed. The increment of the dynamic modulus for the PEEK nanocomposites is up to 40% at elevated temperatures from 100 to 250
°C, indicating the apparent improvement of elevated temperature mechanical properties.
Summary
Enterohaemorrhagic Escherichia coli (EHEC) causes life‐threatening infections in humans as a consequence of the production of Shiga‐like toxins. Lack of a good animal model system currently ...hinders in vivo study of EHEC virulence by systematic genetic methods. Here we applied the genetically tractable animal, Caenorhabditis elegans, as a surrogate host to study the virulence of EHEC as well as the host immunity to this human pathogen. Our results show that E. coli O157:H7, a serotype of EHEC, infects and kills C. elegans. Bacterial colonization and induction of the characteristic attaching and effacing (A/E) lesions in the intact intestinal epithelium of C. elegans by E. coli O157:H7 were concomitantly demonstrated in vivo. Genetic analysis indicated that the Shiga‐like toxin 1 (Stx1) of E. coli O157:H7 is a virulence factor in C. elegans and is required for full toxicity. Moreover, the C. elegans p38 mitogen‐activated protein kinase (MAPK) pathway, anevolutionarily conserved innate immune and stress response signalling pathway, is activated in the regulation of host susceptibility to EHEC infection in a Stx1‐dependent manner. Our results validate the EHEC–C. elegans interaction as suitable for future comprehensive genetic screens for both novel bacterial and host factors involved in the pathogenesis of EHEC infection.
PDF
