Nitrogenase cofactor biosynthesis using proteins produced in mitochondria of .

Biological nitrogen fixation, the conversion of inert N to metabolically tractable NH, is only performed by certain microorganisms called diazotrophs and is catalyzed by the nitrogenases. A [7Fe-9S-C-Mo--homocitrate]-cofactor, designated FeMo-co, provides the catalytic site for N reduction in the Mo-dependent nitrogenase. Thus, achieving FeMo-co formation in model eukaryotic organisms, such as , represents an important milestone toward endowing them with a capacity for Mo-dependent biological nitrogen fixation.

Distraction suppresses high-fat flavor perception.

Distraction during eating contributes to overeating, and when habitually eating with distraction, this may contribute to the development of obesity. One of the proposed mediating mechanisms is the suppression of intensity perception in odor and taste. The effect of distraction on fat intensity perception in flavor, the multisensory combination of odor, taste, and other sensory aspects, is still unknown.

Multiple hydrogen-bonded dimers: are only the frontier atoms relevant?

Non-frontier atom exchanges in hydrogen-bonded aromatic dimers can induce significant interaction energy changes (up to 6.5 kcal mol). Our quantum-chemical analyses reveal that the relative hydrogen-bond strengths of -edited guanine-cytosine base pair isosteres, which cannot be explained from the frontier atoms, follow from the charge accumulation in the monomers.

Odour-imagery ability is linked to food craving, intake, and adiposity change in humans.

It is well-known that food-cue reactivity (FCR) is positively associated with body mass index (BMI) and weight change, but the mechanisms underlying these relationships are incompletely understood. One prominent theory of craving posits that the elaboration of a desired substance through sensory imagery intensifies cravings, thereby promoting consumption. Olfaction is integral to food perception, yet the ability to imagine odours varies widely.

Covid-19 affects taste independent of taste-smell confusions: results from a combined chemosensory home test and online survey from a large global cohort.

People often confuse smell loss with taste loss, so it is unclear how much gustatory function is reduced in patients self-reporting taste loss. Our pre-registered cross-sectional study design included an online survey in 12 languages with instructions for self-administering chemosensory tests with 10 household items. Between June 2020 and March 2021, 10,953 individuals participated.

Odor imagery but not perception drives risk for food cue reactivity and increased adiposity.

Mental imagery has been proposed to play a critical role in the amplification of cravings. Here we tested whether olfactory imagery drives food cue reactivity strength to promote adiposity in 45 healthy individuals. We measured odor perception, odor imagery ability, and food cue reactivity using self-report, perceptual testing, and neuroimaging.

Lessons for Oral Bioavailability: How Conformationally Flexible Cyclic Peptides Enter and Cross Lipid Membranes.

Cyclic peptides extend the druggable target space due to their size, flexibility, and hydrogen-bonding capacity. However, these properties impact also their passive membrane permeability. As the "journey" through membranes cannot be monitored experimentally, little is known about the underlying process, which hinders rational design.

Covid-19 affects taste independently of smell: results from a combined chemosensory home test and online survey from a global cohort (N=10,953).

People often confuse smell loss with taste loss, so it is unclear how much gustatory function is reduced in patients self-reporting taste loss. Our pre-registered cross-sectional study design included an online survey in 12 languages with instructions for self-administering chemosensory tests with ten household items. Between June 2020 and March 2021, 10,953 individuals participated.

Non-invasive vagus nerve stimulation in a hungry state decreases heart rate variability.

Vagus nerve signals from the gut to brain carry information about nutrients and drive food reward. Such signals are disrupted by consuming large amounts of high-calorie foods, necessitating greater food intake to elicit a similar neural response. Non-invasive vagus nerve stimulation (nVNS) via a branch innervating the ear is a candidate treatment for obesity in humans.

A colorimetric method to measure in vitro nitrogenase functionality for engineering nitrogen fixation.

Biological nitrogen fixation (BNF) is the reduction of N into NH in a group of prokaryotes by an extremely O-sensitive protein complex called nitrogenase. Transfer of the BNF pathway directly into plants, rather than by association with microorganisms, could generate crops that are less dependent on synthetic nitrogen fertilizers and increase agricultural productivity and sustainability. In the laboratory, nitrogenase activity is commonly determined by measuring ethylene produced from the nitrogenase-dependent reduction of acetylene (ARA) using a gas chromatograph.

Future Directions for Chemosensory Connectomes: Best Practices and Specific Challenges.

Ecological chemosensory stimuli almost always evoke responses in more than one sensory system. Moreover, any sensory processing takes place along a hierarchy of brain regions. So far, the field of chemosensory neuroimaging is dominated by studies that examine the role of brain regions in isolation.

Large-scale GWAS of food liking reveals genetic determinants and genetic correlations with distinct neurophysiological traits.

We present the results of a GWAS of food liking conducted on 161,625 participants from the UK-Biobank. Liking was assessed over 139 specific foods using a 9-point scale. Genetic correlations coupled with structural equation modelling identified a multi-level hierarchical map of food-liking with three main dimensions: "Highly-palatable", "Acquired" and "Low-caloric".

A follow-up on quantitative and qualitative olfactory dysfunction and other symptoms in patients recovering from COVID-19 smell loss.

Background: Sudden smell loss is a specific early symptom of COVID-19, which, prior to the emergence of Omicron, had estimated prevalence of ~40% to 75%. Chemosensory impairments affect physical and mental health, and dietary behavior. Thus, it is critical to understand the rate and time course of smell recovery.

COVID-19 related chemosensory changes in individuals with self-reported obesity.

Background/objectives: Self-reported smell loss is a prominent symptom of COVID-19 infection and a potentially useful clinical tool for remote pre-screening of this disease. However, pre-existing chemosensory dysfunction with obesity may diminish the usefulness of self-reported smell loss in this vulnerable group. Here we aim to compare COVID-19 related chemosensory alterations in participants with and without obesity and determine if self-reported smell loss is predictive of lab-based COVID-19 diagnosis in both groups in the context of restrictive clinical data collection.

Massively collaborative crowdsourced research on COVID19 and the chemical senses: Insights and outcomes.

In March 2020, the Global Consortium of Chemosensory Research (GCCR) was founded by chemosensory researchers to address emerging reports of unusual smell and taste dysfunction arising from the SARS-CoV-2 pandemic. Over the next year, the GCCR used a highly collaborative model, along with contemporary Open Science practices, to produce multiple high impact publications on chemosensation and COVID19. This invited manuscript describes the founding of the GCCR, the tools and approaches it used, and a summary of findings to date.

One Year Follow-Up of Taste-Related Reward Associations with Weight Loss Suggests a Critical Time to Mitigate Weight Regain Following Bariatric Surgery.

Background: Weight regain is a concerning issue in bariatric patients. We previously demonstrated that taste-related reward processing was associated with six-month weight loss outcomes following Roux-en-Y gastric bypass (RYGB) but not vertical sleeve gastrectomy (VSG). Here, we assessed whether these taste factors persisted in predicting weight loss, and weight regain, at one year post-surgery.

Nonpharmacologic Pain Management Among Hospitalized Inpatients: A Randomized Waitlist-Controlled Trial of Standard Virtual Reality (CGI VR) Versus Video Capture VR (360 degrees 3D/Stereoscopic Video Capture VR).

Objectives: Nonpharmacologic pain management strategies are needed because of the growing opioid epidemic. While studies have examined the efficacy of virtual reality (VR) for pain reduction, there is little research in adult inpatient settings, and no studies comparing the relative efficacy of standard animated computer-generated imagery (CGI) VR to Video Capture VR (360 degrees 3D/stereoscopic Video Capture VR). Here, we report on a randomized controlled trial of the relative efficacy of standard CGI VR versus Video Capture VR (matched for content) and also compared the overall efficacy of VR to a waitlist control group.

International Consensus Based Review and Recommendations for Minimum Reporting Standards in Research on Transcutaneous Vagus Nerve Stimulation (Version 2020).

Given its non-invasive nature, there is increasing interest in the use of transcutaneous vagus nerve stimulation (tVNS) across basic, translational and clinical research. Contemporaneously, tVNS can be achieved by stimulating either the auricular branch or the cervical bundle of the vagus nerve, referred to as transcutaneous auricular vagus nerve stimulation(VNS) and transcutaneous cervical VNS, respectively. In order to advance the field in a systematic manner, studies using these technologies need to adequately report sufficient methodological detail to enable comparison of results between studies, replication of studies, as well as enhancing study participant safety.

COVID-19 Related Chemosensory Changes in Individuals with Self-Reported Obesity.

Background/objectives: Individuals with obesity show alterations in smell and taste abilities. Smell and taste loss are also the most prominent neurological symptoms of COVID-19, yet how chemosensory ability present in individuals with obesity with a positive COVID-19 diagnosis is unknown.

Subjects/methods: In this secondary analysis of a cross-sectional global dataset, we compared self-reported chemosensory ability in participants with a respiratory illness reporting a positive (C19+; n = 5156) or a negative (C19-; n = 659) COVID-19 laboratory test outcome, who also self-reported to be obese (C19+; n = 433, C19-; n = 86) or non-obese.

Biosynthesis of cofactor-activatable iron-only nitrogenase in Saccharomyces cerevisiae.

Engineering nitrogenase in eukaryotes is hampered by its genetic complexity and by the oxygen sensitivity of its protein components. Of the three types of nitrogenases, the Fe-only nitrogenase is considered the simplest one because its function depends on fewer gene products than the homologous and more complex Mo and V nitrogenases. Here, we show the expression of stable Fe-only nitrogenase component proteins in the low-oxygen mitochondria matrix of S.

Recent Smell Loss Is the Best Predictor of COVID-19 Among Individuals With Recent Respiratory Symptoms.

In a preregistered, cross-sectional study, we investigated whether olfactory loss is a reliable predictor of COVID-19 using a crowdsourced questionnaire in 23 languages to assess symptoms in individuals self-reporting recent respiratory illness. We quantified changes in chemosensory abilities during the course of the respiratory illness using 0-100 visual analog scales (VAS) for participants reporting a positive (C19+; n = 4148) or negative (C19-; n = 546) COVID-19 laboratory test outcome. Logistic regression models identified univariate and multivariate predictors of COVID-19 status and post-COVID-19 olfactory recovery.

tVNS Increases Liking of Orally Sampled Low-Fat Foods: A Pilot Study.

Recently a role for the vagus nerve in conditioning food preferences was established in rodents. In a prospective controlled clinical trial in humans, invasive vagus nerve stimulation shifted food choice toward lower fat content. Here we explored whether hedonic aspects of an orally sampled food stimulus can be modulated by non-invasive transcutaneous vagus nerve stimulation (tVNS) in humans.