A permeability assay for mouse intestinal organoids

Here, we describe an assay for intestinal permeability in mouse intestinal organoids, although this may also be adapted for other species. Propidium iodide (PI) does not penetrate intact biological membranes and thus cannot enter the lumen of intact organoids. Passage of PI within the lumen can be induced by tight junction disruption or epithelial cell death. This technique measures PI-stained extruded dead cells within the organoid lumen to analyze the effect of insults, toxins, or treatments on intestinal organoid permeability

SARS-CoV-2 infection and liver involvement

The COVID-19 pandemic is the largest public health challenge in living memory. Patients with underlying liver disease have been disproportionately affected, experiencing high morbidity and mortality. In addition, elevated liver enzymes appear to be a risk factor for disease progression, even in the absence of underlying liver disease. Nevertheless, the mechanism of liver injury in SARS-CoV-2 infection remains largely unknown. This review aims to provide an overview of the mechanisms by which SARS-CoV-2 induces liver injury, and the impact of COVID-19 on cirrhosis, alcohol-related liver disease, autoimmune liver disease, non-alcoholic fatty liver disease, hepatitis B and C virus infection, liver-transplant recipients and patients with hepatocellular carcinoma. Finally, emerging data on vaccination in liver diseases is discussed, to help inform public health policy

Advantages of the recursive operability analysis in updating the risk assessment

With the introduction of new regulations and sustainable technologies, revamping and upgrading already existing chemical plants is nowadays an important element in the framework of process engineering. Such important modifications must come along in parallel improvement of process safety. In this sense, risk assessment is a tool that should be versatile and easy to update by definition. However, even the most common methods currently used for accidental scenarios identification and risk assessment estimation (such as HazOp) may prove to be very time-consuming when discussing about safety from process modifications. The availability of a reliable and easy-to-update tool for safety engineering is crucial for process industries. In this work, we compare a risk analysis on a chemical plant subject of modifications performed with two different tools: HazOp and FTA vs Recursive Operability Analysis (ROA) and FTA. Both techniques have been applied to a tank dedicated to dust mixing that was subject of process modifications. Both methods come to the same conclusions, highlighting new failures and process criticalities, associated with the introduction of flow alarms and interlocks in case of excessive depressurizing. It is shown that the Recursive Operability Analysis, with its cause-consequence structure tied with process variable interactions, is much more effective in a risk assessment update

Placental transporter localization and expression in the Human : the importance of species, sex, and gestational age differences

Grant Support: This work was supported by the Medical Research Council, UK (MR/L010011/1 to PAF, PJOS) and a Glasgow Children's Hospital Charity Research Fund and University of Aberdeen, UK, Elphinstone Scholarship to NW.Peer reviewedPublisher PD

Maternal smoking and high BMI disrupt thyroid gland development

This study was supported by grants from the Medical Research Council (MR/L010011/1) (to PAF & PJOS), the Natural Science and Engineering Research Council of Canada (NSERC) for TK and SHK, and NHS Endowment Grant (to PF).Peer reviewedPublisher PD

Ubiquitination dynamics in the early-branching eukaryote Giardia intestinalis

Ubiquitination is a highly dynamic and versatile posttranslational modification that regulates protein function, stability, and interactions. To investigate the roles of ubiquitination in a primitive eukaryotic lineage, we utilized the early-branching eukaryote Giardia intestinalis. Using a combination of biochemical, immunofluorescence-based, and proteomics approaches, we assessed the ubiquitination status during the process of differentiation in Giardia. We observed that different types of ubiquitin modifications present specific cellular and temporal distribution throughout the Giardia life cycle from trophozoites to cyst maturation. Ubiquitin signal was detected in the wall of mature cysts, and enzymes implicated in cyst wall biogenesis were identified as substrates for ubiquitination. Interestingly, inhibition of proteasome activity did not affect trophozoite replication and differentiation, while it caused a decrease in cyst viability, arguing for proteasome involvement in cyst wall maturation. Using a proteomics approach, we identified around 200 high-confidence ubiquitinated candidates that vary their ubiquitination status during differentiation. Our results indicate that ubiquitination is critical for several cellular processes in this primitive eukaryote

A novel ubiquitin mark at the N-terminal tail of histone H2As targeted by RNF168 ubiquitin ligase

Ubiquitination of histones plays a critical role in the regulation of several processes within the nucleus, including maintenance of genome stability and transcriptional regulation. The only known ubiquitination site on histones is represented by a conserved Lys residue located at the C terminus of the protein. Here, we describe a novel ubiquitin mark at the N-terminal tail of histone H2As consisting of two Lys residues at positions 13 and 15 (K13/K15). This "bidentate" site is a target of the DNA damage response (DDR) ubiquitin ligases RNF8 and RNF168. Histone mutants lacking the K13/K15 site impair RNF168- and DNA damage-dependent ubiquitination. Conversely, inactivation of the canonical C-terminal site prevents the constitutive monoubiquitination of histone H2As but does not abolish the ubiquitination induced by RNF168. A ubiquitination-defective mutant is obtained by inactivating both the N- and the C-terminal sites, suggesting that these are unique, non-redundant acceptors of ubiquitination on histone H2As. This unprecedented result implies that RNF168 generates a qualitatively different Ub mark on chromatin