Roles of ubiquitin and stress in diacetyl chemosensation of C. elegans

Ubiquitin is a small protein that can be attached to other proteins in a cell, tagging them for destruction. The process of adding ubiquitin to a protein substrate (ubiquitination), and the subsequent trafficking and degradation of this substrate, is a principle regulator of the abundance and activity of many proteins across all forms of life. We are examining the role and dynamics of this regulatory system in the olfactory neurons of the model organism Caenorhabditis elegans, specifically the olfactory receptor protein ODR-10, which allows the worm to detect diacetyl, a volatile compound that is produced by the bacteria the worm eats. Without ODR-10, worms cannot properly perform “chemotaxis”—detection and movement towards food (Bargmann et al., 1996). Bargmann et al., 1996). Methodology: To further characterize how the ubiquitin degradation pathway functions to regulate the worm’s sense of smell and the trafficking of ODR-10, we put worms with ubiquitin pathway mutations under conditions of food stress and compared both their food-seeking behavior and ODR-10 abundance/localization within the AWA neuron to the wild-type strain. The ubiquitin-mediated degradation pathway is known to regulate other cell-surface receptors in neurons (Kowalski et al., 2011), and by testing the diacetyl-sensing ability of worms with mutations in this pathway, we found that abnormal ubiquitination in the ODR-10 expressing neuron (“AWA”) leads to reduced diacetyl detection in the worm (Fig. 1) , suggesting that the ubiquitin pathway is indeed involved in regulating ODR-10 (Fig. 2). To further characterize how the ubiquitin degradation pathway functions to regulate the worm’s sense of smell and the trafficking of ODR-10, we put worms with ubiquitin pathway mutations under conditions of food stress and compared both their food-seeking behavior and ODR-10 abundance/localization within the AWA neuron to the wild-type strain. We found that while little difference in chemotaxis ability is observed between the mutant strains, the fraction of worms with visible ODR-10 fluorescence varies significantly, suggesting that mechanisms besides ubiquitination to regulate olfaction may be at play

The effect of lutein- and zeaxanthin-rich foods v. supplements on macular pigment level and serological markers of endothelial activation inflammation and oxidation pilot studies in healthy volunteers: pilot studies in healthy volunteers

The aim of the present study was to compare the effect of lutein- and zeaxanthin-rich foods and supplements on macular pigment level (MPL) and serological markers of endothelial activation, inflammation and oxidation in healthy volunteers. We conducted two 8-week intervention studies. Study 1 (n 52) subjects were randomised to receive either carrot juice (a carotene-rich food) or spinach powder (a lutein- and zeaxanthin-rich food) for 8 weeks. Study 2 subjects (n 75) received supplements containing lutein and zeaxanthin, β-carotene, or placebo for 8 weeks in a randomised, double-blind, placebo-controlled trial. MPL, serum concentrations of lipid-soluble antioxidants, inter-cellular adhesion molecule 1, vascular cell adhesion molecule 1, C-reactive protein and F2-isoprostane levels were assessed at baseline and post-intervention in both studies. In these intervention studies, no effects on MPL or markers of endothelial activation, inflammation or oxidation were observed. However, the change in serum lutein and zeaxanthin was associated or tended to be associated with the change in MPL in those receiving lutein- and zeaxanthin-rich foods (lutein r 0·40, P = 0·05; zeaxanthin r 0·30, P = 0·14) or the lutein and zeaxanthin supplement (lutein r 0·43, P = 0·03; zeaxanthin r 0·22, P = 0·28). In both studies, the change in MPL was associated with baseline MPL (food study r − 0·54, P &lt; 0·001; supplement study r − 0·40, P &lt; 0·001). We conclude that this 8-week supplementation with lutein and zeaxanthin, whether as foods or as supplements, had no significant effect on MPL or serological markers of endothelial activation, inflammation and oxidation in healthy volunteers, but may improve MPL in the highest serum responders and in those with initially low MPL.</jats:p

Neovascular Age-Related Macular Degeneration Risk Based on CFH, LOC387715/HTRA1, and Smoking

Anne Hughes and colleagues show that an individual's risk of developing age-related macular degeneration in old age can be predicted by combining haplotype data with smoking status

ISCEV guidelines for calibration and verification of stimuli and recording instruments (2023 update)

This document developed by the International Society for Clinical Electrophysiology of Vision (ISCEV) provides guidance for calibration and verification of stimulus and recording systems specific to clinical electrophysiology of vision. This guideline provides additional information for those using ISCEV Standards and Extended protocols and supersedes earlier Guidelines. The ISCEV guidelines for calibration and verification of stimuli and recording instruments (2023 update) were approved by the ISCEV Board of Directors 01, March 2023

Comparison of various characteristics of women who do and do not attend for breast cancer screening

BACKGROUND: Information regarding the characteristics and health of women who do and do not attend for breast cancer screening is limited and representative data are difficult to obtain. METHODS: Information on age, deprivation and prescriptions for various medications was obtained for all women at two UK general practices who were invited to breast cancer screening through the National Health Service Breast Screening Programme. The characteristics of women who attended and did not attend screening were compared. RESULTS: Of the 1064 women invited to screening from the two practices, 882 (83%) attended screening. Screening attenders were of a similar age to non-attenders but came from significantly less deprived areas (30% of attenders versus 50% of non-attenders came from the most deprived areas, P < 0.0001) and were more likely to have a current prescription for hormone replacement therapy (32% versus 19%, P < 0.0001). No significant differences in recent prescriptions of medication for hypertension, heart disease, hypercholesterolaemia, diabetes mellitus, asthma, thyroid disease or depression/anxiety were observed between attenders and non-attenders. CONCLUSION: Women who attend the National Health Service Breast Screening Programme come from less deprived areas and are more likely to have a current prescription for hormone replacement therapy than non-attenders, but do not differ in terms of age or recent prescriptions for various other medications

Longitudinal community plasma HIV-1 RNA concentrations and incidence of HIV-1 among injecting drug users: prospective cohort study

Objective To examine the relation between plasma HIV-1 RNA concentrations in the community and HIV incidence among injecting drug users