Biosensor immunoassay for traces of hazelnut protein in olive oil

The fraudulent addition of hazelnut oil to more expensive olive oil not only causes economical loss but may also result in problems for allergic individuals as they may inadvertently be exposed to potentially allergenic hazelnut proteins. To improve consumer safety, a rapid and sensitive direct biosensor immunoassay, based on a highly specific monoclonal antibody, was developed to detect the presence of hazelnut proteins in olive oils. The sample preparation was easy (extraction with buffer); the assay time was fast (4.5 min only) and the limit of detection was low (0.08 μg/g of hazelnut proteins in olive oil). Recoveries obtained with an olive oil mixed with different amounts of a hazelnut protein containing hazelnut oil varied between 93% and 109%

Processive Movement by a Kinesin Heterodimer with an Inactivating Mutation in One Head†

ABSTRACT: A single molecule of the motor enzyme kinesin-1 keeps a tight grip on its microtubule track, making tens or hundreds of discrete, unidirectional 8 nm steps before dissociating. This high duty ratio processive movement is thought to require a mechanism in which alternating stepping of the two head domains of the kinesin dimer is driven by alternating, overlapped cycles of ATP hydrolysis by the two heads. The R210K point mutation in Drosophila kinesin heavy chain was reported to disrupt the ability of the enzyme active site to catalyze ATP P-O bond cleavage. We expressed R210K homodimers as well as isolated R210K heads and confirmed that both are essentially inactive. We then coexpressed tagged R210K subunits with untagged wild-type subunits and affinity purified R210K/wild-type heterodimers together with the inactive R210K homodimers. In contrast to the R210K head or homodimer, the heterodimer was a highly active (>50 % of wild-type) microtubule-stimulated ATPase, and the heterodimer displayed high duty ratio processive movement in single-molecule motility experiments. Thus, dimerization of a subunit containing the inactivating mutation with a functional subunit can complement the mutation; this must occur either by lowering or by bypassing kinetic barriers in the ATPase or mechanical cycles of the mutant head. The observations provide support for kinesin-1 gating mechanisms in which one head stimulates the rate of essential processes in the other

Approaches to assess IgE mediated allergy risks (sensitization and cross-reactivity) from new or modified dietary proteins

The development and introduction of new dietary protein sources has the potential to improve food supply sustainability. Understanding the potential allergenicity of these new or modified proteins is crucial to ensure protection of public health. Exposure to new proteins may result in de novo sensitization, with or without clinical allergy, or clinical reactions through cross-reactivity. In this paper we review the potential of current methodologies (in silico, in vitro degradation, in vitro IgE binding, animal models and clinical studies) to address these outcomes for risk assessment purposes for new proteins, and especially to identify and characterise the risk of sensitization for IgE mediated allergy from oral exposure. Existing tools and tests are capable of assessing potential crossreactivity. However, there are few possibilities to assess the hazard due to de novo sensitization. The only methods available are in vivo models, but many limitations exist to use them for assessing risk. We conclude that there is a need to understand which criteria adequately define allergenicity for risk assessment purposes, and from these criteria develop a more suitable battery of tests to distinguish between proteins of high and low allergenicity, which can then be applied to assess new proteins with unknown risks. © 2017 The Authors Chemicals/CAS: immunoglobulin E, 37341-29-

How does dose impact on the severity of food-induced allergic reactions, and can this improve risk assessment for allergenic foods?

Funding informationThis work was conducted by an expert group of the European branch of the International Life Sciences Institute, ILSI Europe. This publication was coordinated by the Food Allergy Task Force. Industry members of this task force are listed on the ILSI Europe website at http://ilsi.eu/task-forces/food-safety/food-allergy/. Experts are not paid for the time spent on this work; however, the nonindustry members within the expert group were offered support for travel and accommodation costs from the Food Allergy Task Force to attend meetings to discuss the manuscript and a small compensatory sum (honorarium) with the option to decline. The expert group carried out the work, that is collecting/analysing data/information and writing the scientific paper separate to other activities of the task force. The research reported is the result of a scientific evaluation in line with ILSI Europe's framework to provide a precompetitive setting for public‐private partnership. ILSI Europe facilitated scientific meetings and coordinated the overall project management and administrative tasks relating to the completion of this work. For further information about ILSI Europe, please email [email protected] or call +3227710014. The opinions expressed herein and the conclusions of this publication are those of the authors and do not necessarily represent the views of ILSI Europe nor those of its member companies or any regulatory authority

Burden and associated phenotypic characteristics of tuberculosis infection in adult Africans with diabetes: a systematic review.

Diabetes mellitus (DM) increases the risk of developing tuberculosis infection (TBI). However, the evidence on the burden and phenotypic characteristics of TBI in African patients with DM is limited. This study aimed to determine the prevalence and characterisation of TBI in native African patients living with DM. We searched PubMed, EMBASE, and African Journals Online for original studies reporting information on the prevalence and characteristics of TBI in adult Africans with DM. A forest plot was used to describe the pooled prevalence estimate of TBI and the corresponding 95% confidence intervals (CI). Six studies conducted in four African countries involving 721 participants with DM were included in this systematic review. The pooled prevalence estimate of TBI was 40% (95% CI 20-60%, I2 = 98.52%, p < 0.001). Age ≥ 40 years and glycated haemoglobin levels independently predicted TBI positivity in patients with DM in three studies. Africans with DM have a high prevalence of TBI, especially those who are older or with poorly controlled diabetes. This justifies the need for studies to explore how to screen and manage TBI to avert the progression to active TB disease

Genome Scan of M. tuberculosis Infection and Disease in Ugandans

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is an enduring public health problem globally, particularly in sub-Saharan Africa. Several studies have suggested a role for host genetic susceptibility in increased risk for TB but results across studies have been equivocal. As part of a household contact study of Mtb infection and disease in Kampala, Uganda, we have taken a unique approach to the study of genetic susceptibility to TB, by studying three phenotypes. First, we analyzed culture confirmed TB disease compared to latent Mtb infection (LTBI) or lack of Mtb infection. Second, we analyzed resistance to Mtb infection in the face of continuous exposure, defined by a persistently negative tuberculin skin test (PTST-); this outcome was contrasted to LTBI. Third, we analyzed an intermediate phenotype, tumor necrosis factor-alpha (TNFα) expression in response to soluble Mtb ligands enriched with molecules secreted from Mtb (culture filtrate). We conducted a full microsatellite genome scan, using genotypes generated by the Center for Medical Genetics at Marshfield. Multipoint model-free linkage analysis was conducted using an extension of the Haseman-Elston regression model that includes half sibling pairs, and HIV status was included as a covariate in the model. The analysis included 803 individuals from 193 pedigrees, comprising 258 full sibling pairs and 175 half sibling pairs. Suggestive linkage (p<10−3) was observed on chromosomes 2q21-2q24 and 5p13-5q22 for PTST-, and on chromosome 7p22-7p21 for TB; these findings for PTST- are novel and the chromosome 7 region contains the IL6 gene. In addition, we replicated recent linkage findings on chromosome 20q13 for TB (p = 0.002). We also observed linkage at the nominal α = 0.05 threshold to a number of promising candidate genes, SLC11A1 (PTST- p = 0.02), IL-1 complex (TB p = 0.01), IL12BR2 (TNFα p = 0.006), IL12A (TB p = 0.02) and IFNGR2 (TNFα p = 0.002). These results confirm not only that genetic factors influence the interaction between humans and Mtb but more importantly that they differ according to the outcome of that interaction: exposure but no infection, infection without progression to disease, or progression of infection to disease. Many of the genetic factors for each of these stages are part of the innate immune system

Prime movers : mechanochemistry of mitotic kinesins

Mitotic spindles are self-organizing protein machines that harness teams of multiple force generators to drive chromosome segregation. Kinesins are key members of these force-generating teams. Different kinesins walk directionally along dynamic microtubules, anchor, crosslink, align and sort microtubules into polarized bundles, and influence microtubule dynamics by interacting with microtubule tips. The mechanochemical mechanisms of these kinesins are specialized to enable each type to make a specific contribution to spindle self-organization and chromosome segregation

A High-Throughput Screen for Tuberculosis Progression

One-third of the world population is infected with Mycobacterium tuberculosis and multi-drug resistant strains are rapidly evolving. The noticeable absence of a whole organism high-throughput screening system for studying the progression of tuberculosis is fast becoming the bottleneck in tuberculosis research. We successfully developed such a system using the zebrafish Mycobacterium marinum infection model, which is a well-characterized model for tuberculosis progression with biomedical significance, mimicking hallmarks of human tuberculosis pathology. Importantly, we demonstrate the suitability of our system to directly study M. tuberculosis, showing for the first time that the human pathogen can propagate in this vertebrate model, resulting in similar early disease symptoms to those observed upon M. marinum infection. Our system is capable of screening for disease progression via robotic yolk injection of early embryos and visual flow screening of late-stage larvae. We also show that this system can reliably recapitulate the standard caudal vein injection method with a throughput level of 2,000 embryos per hour. We additionally demonstrate the possibility of studying signal transduction leading to disease progression using reverse genetics at high-throughput levels. Importantly, we use reference compounds to validate our system in the testing of molecules that prevent tuberculosis progression, making it highly suited for investigating novel anti-tuberculosis compounds in vivo

Rifapentine and isoniazid for prevention of tuberculosis in people with diabetes (PROTID): protocol for a randomised controlled trial.

BACKGROUND: Diabetes mellitus (DM) increases the risk of tuberculosis (TB) and will hamper global TB control due to the dramatic rise in type 2 DM in TB-endemic settings. In this trial, we will examine the efficacy and safety of TB preventive therapy against the development of TB disease in people with DM who have latent TB infection (LTBI), with a 12-week course of rifapentine and isoniazid (3HP). METHODS: The 'Prevention of tuberculosis in diabetes mellitus' (PROTID) consortium will randomise 3000 HIV-negative eligible adults with DM and LTBI, as evidenced by a positive tuberculin skin test or interferon gamma release assay, to 12 weeks of 3HP or placebo. Participants will be recruited through screening adult patients attending DM clinics at referral hospitals in Tanzania and Uganda. Patients with previous TB disease or treatment with a rifamycin medication or isoniazid (INH) in the previous 2 years will be excluded. The primary outcome is the occurrence of definite or probable TB disease; secondary outcome measures include adverse events, all-cause mortality and treatment completion. The primary efficacy analysis will be intention-to-treat; per-protocol analyses will also be carried out. We will estimate the ratio of TB incidence rates in intervention and control groups, adjusting for the study site using Poisson regression. Results will be reported as efficacy estimates (1-rate ratio). Cumulative incidence rates allowing for death as a competing risk will also be reported. Approximately 1000 LTBI-negative, HIV-negative participants will be enrolled consecutively into a parallel cohort study to compare the incidence of TB in people with DM who are LTBI negative vs positive. A number of sub-studies will be conducted among others to examine the prevalence of LTBI and active TB, estimate the population impact and cost-effectiveness of LTBI treatment in people living with DM in these African countries and address gaps in the prevention and therapeutic management of combined TB-DM. DISCUSSION: PROTID is anticipated to generate key evidence to guide decisions over the use of TB preventive treatment among people with DM as an important target group for better global TB control. TRIAL REGISTRATION: ClinicalTrials.gov NCT04600167 . Registered on 23 October 2020