397 research outputs found
PCB-126 spiked to polyethylene microplastic ingested by juvenile Atlantic cod (Gadus morhua) accumulates in liver and muscle tissues
In the present study, polyethylene (PE) microplastics (150–300 μm) were added to Atlantic cod (Gadus morhua) feeds at 1 %, either in their present form (Virgin PE) or spiked with PCB-126 (Spiked PE). The feeds were given to juvenile cod for a 4-week period. The fish grew from 11 to 23 g with no significant difference between dietary treatments. Cod fed spiked PE showed a significantly higher concentration of PCB-126 in liver and muscle samples compared to control and fish ingesting virgin PE. In accordance with the accumulation of PCB-126 in the liver, the expression of hepatic cyp1a was higher in cod fed spiked PE. Notably, we observed that spiked PE, as well as virgin PE, have an effect on skin. Overall changes indicated a reduced skin barrier in fish fed a diet containing PE. Indicating that PE itself through interaction with gut tissue may influence skin health in fish.PCB-126 spiked to polyethylene microplastic ingested by juvenile Atlantic cod (Gadus morhua) accumulates in liver and muscle tissuespublishedVersio
Macrocycle ring deformation as the secondary design principle for light-harvesting complexes
Natural light-harvesting is performed by pigment-protein complexes, which collect and funnel the solar energy at the start of photosynthesis. The identity and arrangement of pigments largely define the absorption spectrum of the antenna complex, which is further regulated by a palette of structural factors. Small alterations are induced by pigment-protein interactions. In light-harvesting systems 2 and 3 from Rhodoblastus acidophilus, the pigments are arranged identically, yet the former has an absorption peak at 850 nm that is blue-shifted to 820 nm in the latter. While the shift has previously been attributed to the removal of hydrogen bonds, which brings changes in the acetyl moiety of the bacteriochlorophyll, recent work has shown that other mechanisms are also present. Using computational and modeling tools on the corresponding crystal structures, we reach a different conclusion: The most critical factor for the shift is the curvature of the macrocycle ring. The bending of the planar part of the pigment is identified as the second-most important design principle for the function of pigment-protein complexes-a finding that can inspire the design of novel artificial systems
O ModelCiências um portal para o projeto Modelagem Semiquantitativa e Quantitativa na Educação em Ciências
O artigo apresenta alguns fundamentos da modelagem computacional, bem
como algumas das ferramentas que estarão disponÃveis no ModelCiências,
que é um portal do projeto Modelagem Computacional Semiquantitativa e
Quantitativa na Educação em Ciências do Plano Sul de Pesquisa e Pósgraduação
do CNPq. O artigo apresenta, também, as caracterÃsticas dos
cursos a serem disponibilizados no portal, aspectos técnicos de sua construção
e o atual estágio de desenvolvimento do projeto.
The ModelCiências a portal for the Semi Quantitative and Quantitative Computational Modeling in Science Education Project
Abstract
This paper presents some computational modeling basis and also some
modeling tools that will be available in ModelCiências, which is a portal for
the project Semiquantitative and Quantitative Computational Modeling in
Science Education of CNPqs Research and Post-graduation Southern Plan.
The article presents, also, the characteristics of the courses that will be
avaliable in the portal, technical aspects of its construction and the current
stage of development of the project
Dental and Periodontal Health in Acute Intermittent Porphyria
In the inherited metabolic disorder acute intermittent porphyria (AIP), high sugar intake
prevents porphyric attacks due to the glucose effect and the following high insulin levels that
may lower AIP disease activity. Insulin resistance is a known risk factor for periodontitis and
sugar changes diabetogenic hormones and affects dental health. We hypothesized differences in
homeostasis model assessment (HOMA) scores for insulin resistance in AIP cases vs. controls and in
those with periodontitis. Our aim was to systematically study dental health in AIP as poor dental
health was previously only described in case reports. Further, we aimed to examine if poor dental
health and kidney failure might worsen AIP as chronic inflammation and kidney failure might
increase disease activity. In 47 AIP cases and 47 matched controls, X-rays and physical examination
of clinical attachment loss (CAL), probing pocket depth (PPD), and decayed missing filled teeth
(DMFT) were performed. Dietary intake was evaluated through a diet logbook. Plasma cytokines
and diabetogenic hormones were measured using multiplex technology and urine porphobilinogen
and kidney and liver function by routine methods. An excel spreadsheet from the University of
Oxford was used to estimate HOMA scores; beta cell function, HOMA%B (%B), insulin sensitivity,
HOMA%S (%S), and insulin resistance HOMA-IR (IR), based on glucose and plasma (P) C-peptide.
The Wilcoxon matched-pairs signed rank test, the Mann–Whitney U-test, and Spearman’s nonparametric correlation were used. Insulin (p = 0.007) and C-peptide (p = 0.006) were higher in the AIP
cases with periodontitis versus those without. In AIP patients, the liver fibrosis index 4 correlated
with DMFT (p < 0.001) and CAL ≥4 mm (p = 0.006); the estimated glomerular filtration rate correlated
with DMFT (p < 0.001) and CAL ≥4 mm (p = 0.02). CAL ≥4 mm was correlated with chemokine
ligand 11 and interleukin (IL)-13 (p = 0.04 for both), and PPD >5 mm was correlated with plasminogen
activator inhibitor-1 (p = 0.003) and complement component 3 (p = 0.02). In conclusion, dental health
in AIP cases was correlated with insulin resistance, inflammatory markers, and biomarkers of kidney
and liver function, demonstrating that organ damage in the kidney and liver are associated with
poorer dental health
Role of the Neutral Amino Acid Transporter SLC7A10 in Adipocyte Lipid Storage, Obesity and Insulin Resistance
Elucidation of mechanisms that govern lipid storage, oxidative stress, and insulin resistance may lead to improved therapeutic options for type 2 diabetes and other obesity-related diseases. Here, we find that adipose expression of the small neutral amino acid transporter SLC7A10, also known as alanine-serine-cysteine transporter-1 (ASC-1), shows strong inverse correlates with visceral adiposity, insulin resistance, and adipocyte hypertrophy across multiple cohorts. Concordantly, loss of Slc7a10 function in zebrafish in vivo accelerates diet-induced body weight gain and adipocyte enlargement. Mechanistically, SLC7A10 inhibition in human and murine adipocytes decreases adipocyte serine uptake and total glutathione levels and promotes reactive oxygen species (ROS) generation. Conversely, SLC7A10 overexpression decreases ROS generation and increases mitochondrial respiratory capacity. RNA sequencing revealed consistent changes in gene expression between human adipocytes and zebrafish visceral adipose tissue following loss of SLC7A10, e.g., upregulation of SCD (lipid storage) and downregulation of CPT1A (lipid oxidation). Interestingly, ROS scavenger reduced lipid accumulation and attenuated the lipid-storing effect of SLC7A10 inhibition. These data uncover adipocyte SLC7A10 as a novel important regulator of adipocyte resilience to nutrient and oxidative stress, in part by enhancing glutathione levels and mitochondrial respiration, conducive to decreased ROS generation, lipid accumulation, adipocyte hypertrophy, insulin resistance, and type 2 diabetes.acceptedVersio
Lysates of Methylococcus capsulatus Bath induce a lean-like microbiota, intestinal FoxP3+RORγt+IL-17+ Tregs and improve metabolism
Interactions between host and gut microbial communities are modulated by diets and play pivotal roles in immunological homeostasis and health. We show that exchanging the protein source in a high fat, high sugar, westernized diet from casein to whole-cell lysates of the non-commensal bacterium Methylococcus capsulatus Bath is sufficient to reverse western diet-induced changes in the gut microbiota to a state resembling that of lean, low fat diet-fed mice, both under mild thermal stress (T22 °C) and at thermoneutrality (T30 °C). Concomitant with microbiota changes, mice fed the Methylococcus-based western diet exhibit improved glucose regulation, reduced body and liver fat, and diminished hepatic immune infiltration. Intake of the Methylococcu-based diet markedly boosts Parabacteroides abundances in a manner depending on adaptive immunity, and upregulates triple positive (Foxp3+RORγt+IL-17+) regulatory T cells in the small and large intestine. Collectively, these data point to the potential for leveraging the use of McB lysates to improve immunometabolic homeostasis.publishedVersio
Search for non-relativistic Magnetic Monopoles with IceCube
The IceCube Neutrino Observatory is a large Cherenkov detector instrumenting
of Antarctic ice. The detector can be used to search for
signatures of particle physics beyond the Standard Model. Here, we describe the
search for non-relativistic, magnetic monopoles as remnants of the GUT (Grand
Unified Theory) era shortly after the Big Bang. These monopoles may catalyze
the decay of nucleons via the Rubakov-Callan effect with a cross section
suggested to be in the range of to
. In IceCube, the Cherenkov light from nucleon decays
along the monopole trajectory would produce a characteristic hit pattern. This
paper presents the results of an analysis of first data taken from May 2011
until May 2012 with a dedicated slow-particle trigger for DeepCore, a
subdetector of IceCube. A second analysis provides better sensitivity for the
brightest non-relativistic monopoles using data taken from May 2009 until May
2010. In both analyses no monopole signal was observed. For catalysis cross
sections of the flux of non-relativistic
GUT monopoles is constrained up to a level of at a 90% confidence level,
which is three orders of magnitude below the Parker bound. The limits assume a
dominant decay of the proton into a positron and a neutral pion. These results
improve the current best experimental limits by one to two orders of magnitude,
for a wide range of assumed speeds and catalysis cross sections.Comment: 20 pages, 20 figure
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