A conserved metalloprotease mediates ecdysis in Caenorhabditis elegans

Molting is required for progression between larval stages in the life cycle of nematodes. We have identified four mutant alleles of a <i>Caenorhabditis elegans</i> metalloprotease gene, <i>nas-37</i>, that cause incomplete ecdysis. At each molt the cuticle fails to open sufficiently at the anterior end and the partially shed cuticle is dragged behind the animal. The gene is expressed in hypodermal cells 4 hours before ecdysis during all larval stages. The <i>NAS-37</i> protein accumulates in the anterior cuticle and is shed in the cuticle after ecdysis. This pattern of protein accumulation places NAS- 37 in the right place and at the right time to degrade the cuticle to facilitate ecdysis. The nas-37 gene has orthologs in other nematode species, including parasitic nematodes, and they undergo a similar shedding process. For example, <i>Haemonchus contortus</i> molts by digesting a ring of cuticle at the tip of the nose. Incubating <i>Haemonchus</i> larvae in extracted exsheathing fluids causes a refractile ring of digested cuticle to form at the tip of the nose. When <i>Haemonchus</i> cuticles are incubated with purified NAS-37, a similar refractile ring forms. NAS-37 degradation of the <i>Haemonchus</i> cuticle suggests that the metalloproteases and the cuticle substrates involved in exsheathment of parasitic nematodes are conserved in free-living nematodes

Vagal leptin signalling: A double agent in energy homeostasis?

This commentary refers to “Deletion of leptin signaling in vagal afferent neurons results in hyperphagia and obesity by De Lartique et al.”, http://dx.doi.org/10.1016/j. molmet.2014.06.003.Amanda J. Page, Stephen J. Kentis

Building large phylogenetic trees on coarse-grained parallel machines

Phylogenetic analysis is an area of computational biology concerned with the reconstruction of evolutionary relationships between organisms, genes, and gene families. Maximum likelihood evaluation has proven to be one of the most reliable methods for constructing phylogenetic trees. The huge computa- tional requirements associated with maximum likelihood analysis means that it is not feasible to produce large phylogenetic trees using a single processor. We have completed a fully cross platform coarse grained distributed application, DPRml, which overcomes many of the limitations imposed by the current set of parallel phylogenetic programs. We have completed a set of efï¬ciency tests that show how to maximise efï¬ciency while using the program to build large phylogenetic trees. The software is publicly available under the terms of the GNU general public li- cence from the system webpage at http://www.cs.nuim.ie/distribute

Formation of chlorobenzenes by oxidative thermal decomposition of 1,3-dichloropropene

We combine combustion experiments and density functional theory (DFT) calculations to investigate the formation of chlorobenzenes from oxidative thermal decomposition of 1,3-dichloropropene. Mono- to hexa-chlorobenzenes are observed between 800 and 1150. K, and the extent of chlorination was proportional to the combustion temperature. Higher chlorinated congeners of chlorobenzene (tetra-, penta-, hexa-chlorobenzene) are only observed in trace amounts between 950 and 1050. K. DFT calculations indicate that cyclisation of chlorinated hexatrienes proceeds via open-shell radical pathways. These species represent key components in the formation mechanism of chlorinated polyaromatic hydrocarbons. Results presented herein should provide better understanding of the evolution of soot from combustion/pyrolysis of short chlorinated alkenes

A simple example of "Quantum Darwinism": Redundant information storage in many-spin environments

As quantum information science approaches the goal of constructing quantum computers, understanding loss of information through decoherence becomes increasingly important. The information about a system that can be obtained from its environment can facilitate quantum control and error correction. Moreover, observers gain most of their information indirectly, by monitoring (primarily photon) environments of the "objects of interest." Exactly how this information is inscribed in the environment is essential for the emergence of "the classical" from the quantum substrate. In this paper, we examine how many-qubit (or many-spin) environments can store information about a single system. The information lost to the environment can be stored redundantly, or it can be encoded in entangled modes of the environment. We go on to show that randomly chosen states of the environment almost always encode the information so that an observer must capture a majority of the environment to deduce the system's state. Conversely, in the states produced by a typical decoherence process, information about a particular observable of the system is stored redundantly. This selective proliferation of "the fittest information" (known as Quantum Darwinism) plays a key role in choosing the preferred, effectively classical observables of macroscopic systems. The developing appreciation that the environment functions not just as a garbage dump, but as a communication channel, is extending our understanding of the environment's role in the quantum-classical transition beyond the traditional paradigm of decoherence.Comment: 21 pages, 6 figures, RevTex 4. Submitted to Foundations of Physics (Asher Peres Festschrift

3-Dimensional atomic scale structure of the ionic liquid–graphite interface elucidated by AM-AFM and quantum chemical simulations

In situ amplitude modulated atomic force microscopy (AM-AFM) and quantum chemical simulations are used to resolve the structure of the highly ordered pyrolytic graphite (HOPG)–bulk propylammonium nitrate (PAN) interface with resolution comparable with that achieved for frozen ionic liquid (IL) monolayers using STM. This is the first time that (a) molecular resolution images of bulk IL–solid interfaces have been achieved, (b) the lateral structure of the IL graphite interface has been imaged for any IL, (c) AM-AFM has elucidated molecular level structure immersed in a viscous liquid and (d) it has been demonstrated that the IL structure at solid surfaces is a consequence of both thermodynamic and kinetic effects. The lateral structure of the PAN–graphite interface is highly ordered and consists of remarkably well-defined domains of a rhomboidal superstructure composed of propylammonium cations preferentially aligned along two of the three directions in the underlying graphite lattice. The nanostructure is primarily determined by the cation. Van der Waals interactions between the propylammonium chains and the surface mean that the cation is enriched in the surface layer, and is much less mobile than the anion. The presence of a heterogeneous lateral structure at an ionic liquid–solid interface has wide ranging ramifications for ionic liquid applications, including lubrication, capacitive charge storage and electrodeposition

Association of dietary and nutrient patterns with systemic inflammation in community dwelling adults

Purpose: Evidence investigating associations between dietary and nutrient patterns and inflammatory biomarkers is inconsistent and scarce. Therefore, we aimed to determine the association of dietary and nutrient patterns with inflammation. Methods: Overall, 1,792 participants from the North-West Adelaide Health Study were included in this cross-sectional study. We derived dietary and nutrient patterns from food frequency questionnaire data using principal component analysis. Multivariable ordinal logistic regression determined the association between dietary and nutrient patterns and the grade of inflammation (normal, moderate, and severe) based on C-reactive protein (CRP) values. Subgroup analyses were stratified by gender, obesity and metabolic health status. Results: In the fully adjusted model, a plant-sourced nutrient pattern (NP) was strongly associated with a lower grade of inflammation in men (ORQ5vsQ1 = 0.59, 95% CI: 0.38–0.93, p-trend = 0.08), obesity (ORQ5vsQ1 = 0.43; 95% CI: 0.24–0.77, p-trend = 0.03) and metabolically unhealthy obesity (ORQ5vsQ1 = 0.24; 95% CI: 0.11–0.52, p-trend = 0.01). A mixed NP was positively associated with higher grade of inflammation (ORQ5vsQ1 = 1.35; 95% CI: 0.99–1.84, p-trend = 0.03) in all participants. A prudent dietary pattern was inversely associated with a lower grade of inflammation (ORQ5vsQ1 = 0.72, 95% CI: 0.52–1.01, p-trend = 0.14). In contrast, a western dietary pattern and animal-sourced NP were associated with a higher grade of inflammation in the all participants although BMI attenuated the magnitude of association (ORQ5vsQ1 = 0.83, 95% CI: 0.55–1.25; and ORQ5vsQ1 = 0.94, 95% CI: 0.63–1.39, respectively) in the fully adjusted model. Conclusion: A plant-sourced NP was independently associated with lower inflammation. The association was stronger in men, and those classified as obese and metabolically unhealthy obese. Increasing consumption of plant-based foods may mitigate obesity-induced inflammation and its consequences.Yoko Brigitte Wang, Amanda J. Page, Tiany K. Gill, and Yohannes Adama Mela

The association between diet quality, plant-based diets, systemic inflammation, and mortality risk: findings from NHANES

Published online: 22 June 2023. OnlinePublPURPOSE: To our knowledge, no studies have examined the association of diet quality and plant-based diets (PBD) with inflammatory-related mortality in obesity. Therefore, this study aimed to determine the joint associations of Healthy Eating Index-2015 (HEI-2015), plant-based dietary index (PDI), healthy PDI (hPDI), unhealthy PDI (uPDI), pro-vegetarian dietary index (PVD), and systemic inflammation with all-cause, cardiovascular disease (CVD), and cancer mortality risks by obesity status. METHODS: Participants from NHANES were included in cross-sectional (N = 27,915, cycle 1999-2010, 2015-2018) and longitudinal analysis (N = 11,939, cycle 1999-2008). HEI-2015, PDI, hPDI, uPDI, and PVD were constructed based on the 24-h recall dietary interview. The grade of inflammation (low, moderate, and high) was determined based on C-reactive protein (CRP) values and multivariable ordinal logistic regression was used to determine the association. Cox proportional hazard models were used to determine the joint associations of diet and inflammation with mortality. RESULTS: In the fully adjusted model, HEI-2015 (ORT3vsT1 = 0.76, 95% CI 0.69-0.84; p-trend =  < 0.001), PDI (ORT3vsT1 = 0.83, 95% CI 0.75-0.91; p trend =  < 0.001), hPDI (ORT3vsT1 = 0.79, 95% CI 0.71-0.88; p trend =  < 0.001), and PVD (ORT3vsT1 = 0.85, 95% CI 0.75-0.97; p trend = 0.02) were associated with lower systemic inflammation. In contrast, uPDI was associated with higher systemic inflammation (ORT3vsT1 = 1.18, 95% CI 1.06-1.31; p-trend = 0.03). Severe inflammation was associated with a 25% increase in all-cause mortality (ORT3vsT1 = 1.25, 95% CI 1.03-1.53, p trend = 0.02). No association was found between PDI, hPDI, uPDI, and PVD with mortality. The joint association, between HEI-2015, levels of systemic inflammation, and all-cause, CVD and cancer mortality, was not significant. However, a greater reduction in mortality risk with an increase in HEI-2015 scores was observed in individuals with low and moderate inflammation, especially those with obesity. CONCLUSION: Higher scores of HEI-2015 and increased intake of a healthy plant-based diet were associated with lower inflammation, while an unhealthy plant-based diet was associated with higher inflammation. A greater adherence to the 2015 dietary guidelines may reduce the risk of mortality associated with inflammation and may also benefit individuals with obesity who had low and moderate inflammation.Yoko Brigitte Wang, Amanda J. Page, Tiffany K. Gill, Yohannes Adama Melak

Testing the blast wave model with Swift GRBs

The complex structure of the light curves of Swift GRBs has made the identification of breaks, and the interpretation of the blast wave caused by the burst, more difficult than in the pre-Swift era. We aim to identify breaks, which are possibly hidden, and to constrain the blast wave parameters; electron energy distribution, p, density profile of the circumburst medium, k, and the continued energy injection index, q. We do so by comparing the observed multi-wavelength light curves and X-ray spectra of our sample to the predictions of the blast wave model. We can successfully interpret all of the bursts in our sample of 10, except two, within this framework and we can estimate, with confidence, the electron energy distribution index for 6 of the sample. Furthermore we identify jet breaks in a number of the bursts. A statistical analysis of the distribution of p reveals that, even in the most conservative case of least scatter, the values are not consistent with a single, universal value. The values of k suggest that the circumburst density profiles are not drawn from only one of the constant density or wind-like media populations.Comment: 14 pages, accepted by MNRAS after minor changes, including extension of discussion (section 4.3

Seasonal diet changes in elephant and impala in mopane woodland

Elephant and impala as intermediate feeders, having a mixed diet of grass and browse, respond to seasonal fluctuations of forage quality by changing their diet composition. We tested the hypotheses that (1) the decrease in forage quality is accompanied by a change in diet from more monocots in the wet season to more dicots in the dry season and that that change is more pronounced and faster in impala than in elephant; (2) mopane (Colophospermum mopane), the most abundant dicot species, is the most important species in the elephant diet in mopane woodland, whereas impala feed relatively less on mopane due to the high condensed tannin concentration; and (3) impala on nutrient-rich soils have a diet consisting of more grass and change later to diet of more browse than impala on nutrient-poor soils. The phosphorus content and in vitro digestibility of monocots decreased and the NDF content increased significantly towards the end of the wet season, whereas in dicots no significant trend could be detected. We argue that this decreasing monocot quality caused elephant and impala to consume more dicots in the dry season. Elephant changed their diet gradually over a 16-week period from 70% to 25% monocots, whereas impala changed diets rapidly (2-4 weeks) from 95% to 70% monocots. For both elephants and impala, there was a positive correlation between percentage of monocots and dicots in the diet and the in vitro digestibility of these forage items. Mopane was the most important dicot species in the elephant diet and its contribution to the diet increased significantly in the dry season, whereas impala selected other dicot species. On nutrient-rich gabbroic soils, impala ate significantly more monocots than impala from nutrient-poor granitic soils, which was related to the higher in vitro digestibility of the monocots on gabbroic soil. Digestibility of food items appears to be an important determinant of diet change from the wet to the dry season in impala and elephants