Search results for "STABILITY"
showing 10 items of 3085 documents
Health and Disease Imprinted in the Time Variability of the Human Microbiome
2017
The human microbiota correlates closely with the health status of its host. This article analyzes the microbial composition of several subjects under different conditions over time spans that ranged from days to months. Using the Langevin equation as the basis of our mathematical framework to evaluate microbial temporal stability, we proved that stable microbiotas can be distinguished from unstable microbiotas. This initial step will help us to determine how temporal microbiota stability is related to a subject’s health status and to develop a more comprehensive framework that will provide greater insight into this complex system.
Increased RNA virus population diversity improves adaptability
2021
The replication machinery of most RNA viruses lacks proofreading mechanisms. As a result, RNA virus populations harbor a large amount of genetic diversity that confers them the ability to rapidly adapt to changes in their environment. In this work, we investigate whether further increasing the initial population diversity of a model RNA virus can improve adaptation to a single selection pressure, thermal inactivation. For this, we experimentally increased the diversity of coxsackievirus B3 (CVB3) populations across the capsid region. We then compared the ability of these high diversity CVB3 populations to achieve resistance to thermal inactivation relative to standard CVB3 populations in an…
Snapshots of a shrinking partner: Genome reduction inSerratia symbiotica
2016
AbstractGenome reduction is pervasive among maternally-inherited endosymbiotic organisms, from bacteriocyte- to gut-associated ones. This genome erosion is a step-wise process in which once free-living organisms evolve to become obligate associates, thereby losing non-essential or redundant genes/functions. Serratia symbiotica (Gammaproteobacteria), a secondary endosymbiont present in many aphids (Hemiptera: Aphididae), displays various characteristics that make it a good model organism for studying genome reduction. While some strains are of facultative nature, others have established co-obligate associations with their respective aphid host and its primary endosymbiont (Buchnera). Further…
Consensus molecular subtypes of colorectal cancer are recapitulated in in vitro and in vivo models
2018
Colorectal cancer (CRC) is a highly heterogeneous disease both from a molecular and clinical perspective. Several distinct molecular entities, such as microsatellite instability (MSI), have been defined that make up biologically distinct subgroups with their own clinical course. Recent data indicated that CRC can be best segregated into four groups called consensus molecular subtypes (CMS1-4), each of which has a unique biology and gene expression pattern. In order to develop improved, subtype-specific therapies and to gain insight into the molecular wiring and origin of these subtypes, reliable models are needed. This study was designed to determine the heterogeneity and identify the prese…
Additives for vaccine storage to improve thermal stability of adenoviruses from hours to months
2016
Up to 80% of the cost of vaccination programmes is due to the cold chain problem (that is, keeping vaccines cold). Inexpensive, biocompatible additives to slow down the degradation of virus particles would address the problem. Here we propose and characterize additives that, already at very low concentrations, improve the storage time of adenovirus type 5. Anionic gold nanoparticles (10−8–10−6 M) or polyethylene glycol (PEG, molecular weight ∼8,000 Da, 10−7–10−4 M) increase the half-life of a green fluorescent protein expressing adenovirus from ∼48 h to 21 days at 37 °C (from 7 to >30 days at room temperature). They replicate the known stabilizing effect of sucrose, but at several orders of…
Characterizing diversity in the tumor-immune microenvironment of distinct subclasses of gastroesophageal adenocarcinomas
2020
Background Gastroesophageal adenocarcinomas (GEAs) are heterogeneous cancers where immune checkpoint inhibitors have robust efficacy in heavily inflamed microsatellite instability (MSI) or Epstein-Barr virus (EBV)-positive subtypes. Immune checkpoint inhibitor responses are markedly lower in diffuse/genome stable (GS) and chromosomal instable (CIN) GEAs. In contrast to EBV and MSI subtypes, the tumor microenvironment of CIN and GS GEAs have not been fully characterized to date, which limits our ability to improve immunotherapeutic strategies. Patients and methods Here we aimed to identify tumor-immune cell association across GEA subclasses using data from The Cancer Genome Atlas (N = 453 GE…
Role of the antioxidant defence system and telomerase in arsenic-induced genomic instability
2016
Arsenic (AS) is a reactive oxygen species (ROS)-inducer carcinogen, whose mode of action is still unclear. To defend against ROS, cells use enzymatic and non-enzymatic antioxidants, such as superoxide dismutase (SOD) and catalase. Failure of antioxidant systems (AXS) can result in dicentric chromosomes formation as well as telomere associations for the reduced activity of telomerase. In order to clarify the long-term effects of a past AS exposure, we evaluated the efficiency of the AXS and the telomerase activity in the progeny of arsenite-treated cells named ASO (arsenic shake-off) cells, previously obtained from arsenite-treated V79 cells and selected by shake-off. Despite SOD1 expression…
Shelf life study of healthy pork liver pate with added seaweed extracts from Ascophyllum nodosum, Fucus vesiculosus and Bifurcaria bifurcata
2018
The effect of the addition of seaweed extracts from three brown algae species [Ascophyllum nodosum (AN), Fucus vesiculosus (FV) and Bifurcaria bifurcata (BB which are a great source of natural antioxidants, on the oxidative stability of refrigerated low-fat pork liver pates was studied. In the studied pates, half of pork fat was replaced with a mixture consisting of canola and high-oleic sunflower oil (75:25, v/v), thus improving their fatty acid profile in terms of polyunsaturated fatty acids (PUFA). In order to avoid the oxidation of PUFA in the new samples, seaweed extracts (500 ppm) were added. In addition, some samples were formulated with a synthetic antioxidant (BHT at 50 ppm) (BHT) …
Induction of Chromosome Instability by Activation of Yes-Associated Protein and Forkhead Box M1 in Liver Cancer
2016
Background & Aims Many different types of cancer cells have chromosome instability. The hippo pathway leads to phosphorylation of the transcriptional activator yes-associated protein 1 (YAP1, YAP), which regulates proliferation and has been associated with the development of liver cancer. We investigated the effects of hippo signaling via YAP on chromosome stability and hepatocarcinogenesis in humans and mice. Methods We analyzed transcriptome data from 242 patients with hepatocellular carcinoma (HCC) to search for gene signatures associated with chromosomal instability (CIN); we investigated associations with overall survival time and cancer recurrence using Kaplan–Meier curves. We analyze…
Preservation of Multiple Mammalian Tissues to Maximize Science Return from Ground Based and Spaceflight Experiments.
2016
Background Even with recent scientific advancements, challenges posed by limited resources and capabilities at the time of sample dissection continue to limit the collection of high quality tissues from experiments that can be conducted only infrequently and at high cost, such as in space. The resources and time it takes to harvest tissues post-euthanasia, and the methods and duration of long duration storage, potentially have negative impacts on sample quantity and quality, thereby limiting the scientific outcome that can be achieved. Objectives The goals of this study were to optimize methods for both sample recovery and science return from rodent experiments, with possible relevance to b…