Opticool: Cutting-edge transgenic optical tools

Only a few short decades have passed since the sequencing of GFP, yet the modern repertoire of transgenically encoded optical tools implies an exponential proliferation of ever improving constructions to interrogate the subcellular environment. A myriad of tags for labeling proteins, RNA, or DNA have arisen in the last few decades, facilitating unprecedented visualization of subcellular components and processes. Development of a broad array of modern genetically encoded sensors allows real-time, in vivo detection of molecule levels, pH, forces, enzyme activity, and other subcellular and extracellular phenomena in ever expanding contexts. Optogenetic, genetically encoded optically controlled manipulation systems have gained traction in the biological research community and facilitate single-cell, real-time modulation of protein function in vivo in ever broadening, novel applications. While this field continues to explosively expand, references are needed to assist scientists seeking to use and improve these transgenic devices in new and exciting ways to interrogate development and disease. In this review, we endeavor to highlight the state and trajectory of the field of in vivo transgenic optical tools.

[Innovative 3D imaging]

Intraoperative 2D fluoroscopy is often performed for repositioning and implant control. However, this does not always provide the details needed to reliably detect joint steps or incorrect repositioning. Over the last few years, intraoperative 3D imaging has been established and further developed. Multiple studies demonstrate an advantage and better intraoperative control through 3D imaging. Examples are the upper ankle, the proximal tibia and the distal radius; the rates of intraoperative revisions with digital volume tomography (DVT) are between 20-30%. Technical advancements, such as metal artifact reductions, automated plane setting, automated screw detection, and robotic DVT devices, facilitate intraoperative operation, shorten surgical time, and provide improved image quality. By processing the data sets in the form of an immersive, computer-simulated image in terms of "augmented reality" (AR), increased precision can be achieved intraoperatively while reducing radiation exposure. The implementation of these systems is associated with costs, which are offset by cost savings from avoided revisions. Adequate counter-financing is still lacking at the present time. Intraoperative 3D imaging represents an important tool for intraoperative control. The current data situation makes it necessary to address the routine use of 3D procedures, especially in the joint area. The indications are becoming increasingly broader. Technical innovations such as robotics and AR have significantly improved 3D devices in recent years and offer high potential for integration into the OR.

A critical role of retinoic acid concentration for the induction of a fully human-like atrial action potential phenotype in hiPSC-CM

Retinoic acid (RA) induces an atrial phenotype in human induced pluripotent stem cells (hiPSCs), but expression of atrium-selective currents such as the ultrarapid (IKur) and acetylcholine-stimulated K+ current is variable and less than in the adult human atrium. We suspected methodological issues and systematically investigated the concentration dependency of RA. RA treatment increased IKur concentration dependently from 1.1 ± 0.54 pA/pF (0 RA) to 3.8 ± 1.1, 5.8 ± 2.5, and 12.2 ± 4.3 at 0.01, 0.1, and 1 μM, respectively. Only 1 μM RA induced enough IKur to fully reproduce human atrial action potential (AP) shape and a robust shortening of APs upon carbachol. We found that sterile filtration caused substantial loss of RA. We conclude that 1 μM RA seems to be necessary and sufficient to induce a full atrial AP shape in hiPSC-CM in EHT format. RA concentrations are prone to methodological issues and may profoundly impact the success of atrial differentiation.

An arrhythmogenic metabolite in atrial fibrillation

BACKGROUND

Long-chain acyl-carnitines (ACs) are potential arrhythmogenic metabolites. Their role in atrial fibrillation (AF) remains incompletely understood. Using a systems medicine approach, we assessed the contribution of C18:1AC to AF by analysing its in vitro effects on cardiac electrophysiology and metabolism, and translated our findings into the human setting.

METHODS AND RESULTS

Human iPSC-derived engineered heart tissue was exposed to C18:1AC. A biphasic effect on contractile force was observed: short exposure enhanced contractile force, but elicited spontaneous contractions and impaired Ca2+ handling. Continuous exposure provoked an impairment of contractile force. In human atrial mitochondria from AF individuals, C18:1AC inhibited respiration. In a population-based cohort as well as a cohort of patients, high C18:1AC serum concentrations were associated with the incidence and prevalence of AF.

CONCLUSION

Our data provide evidence for an arrhythmogenic potential of the metabolite C18:1AC. The metabolite interferes with mitochondrial metabolism, thereby contributing to contractile dysfunction and shows predictive potential as novel circulating biomarker for risk of AF.

California sea lions interfere with striped marlin hunting behaviour in multi-species predator aggregations

The open ocean offers a suite of ecological conditions promoting the occurrence of multi-species predator aggregations. These mixed predator aggregations typically hunt large groups of relatively small and highly cohesive prey. However, the mechanisms and functions of these mixed predator aggregations are largely unknown. Even basic knowledge of whether the predator species' interactions are mutualistic, commensal or parasitic is typically missing. Moreover, recordings of attack and capture rates of marine multi-species predator aggregations, which are critical in understanding how and why these interactions have evolved, are almost completely non-existent owing to logistical challenges. Using underwater video, we quantified the attack and capture rates of two high-trophic level marine predators, California sea lions (Zalophus californianus) and striped marlin (Kajikia audax) attacking schools of fishes in the Southern California Current System, offshore the Baja California Peninsula. Recording over 5000 individual attacks across 13 fish schools, which varied in species, size and predator composition, we found that sea lions kleptoparasitized striped marlin hunts and reduced the frequency of marlin attacks and captures via interference competition. We discuss our results in the context of the phenotypic differences between the predator species and implications for a better understanding of multi-species predator aggregations. This article is part of the theme issue 'Mixed-species groups and aggregations: shaping ecological and behavioural patterns and processes'.

A genome-wide genetic screen identifies CYRI-B as a negative regulator of CEACAM3-mediated phagocytosis

Opsonin-independent phagocytosis mediated by human carcinoembryonic antigen-related cell adhesion molecule 3 (CEACAM3) has evolved to control a subset of human-restricted bacterial pathogens. CEACAM3 engagement triggers rapid GTP-loading of the small GTPase Rac as a master regulator of cytoskeletal rearrangements and lamellipodia-driven internalization. To identify components of the CEACAM3-initiated signaling cascade, we performed a genome-wide CRISPR/Cas9-based screen in human myeloid cells. Following infection with fluorescently labeled bacteria, cells exhibiting elevated phagocytosis (gain-of-function) as well as cells showing reduced phagocytosis (loss-of-function) were sorted and enrichment of individual single-guide RNAs (sgRNAs) was determined by next generation sequencing. Concentrating on genes whose targeting by three distinct sgRNAs consistently resulted in a gain-of-function phenotype, we identified the Rac-GTP-sequestering protein CYRI-B as a negative regulator of CEACAM3-mediated phagocytosis. Clonal HL-60 cell lines with CYRI-B knockout showed enhanced CEACAM3-downstream signaling, such as Rac GTP loading and phosphorylation of PAK kinases, leading to increased phagocytosis of bacteria. Complementation of the CYRI-B knockout cells reverted the knockout phenotype. Our results unravel components of CEACAM3-initiated opsonin-independent phagocytosis on a genome-wide level and highlight CYRI-B as a negative regulator of CEACAM3-initiated signaling in myeloid cells.

[Distortion of the cervical spine : Pathophysiology, diagnostics, treatment and assessment]

Distortion or whiplash trauma of the cervical spine is an injury pattern associated with motor vehicle collisions and typically occurs after rear impact collisions, but is not limited to this type of collision and accident. The vast majority of these injuries are low-grade injuries according to the Quebec Task Force (QTF) classification, whereby no objective morphological correlates can be determined in clinical and radiological examinations. The prognosis is predominantly favorable and the condition is self-limiting; however, care must be taken with respect to complex courses with chronic pain and the manifestation of neuropsychiatric complaints. Due to the mechanism of the accident this injury pattern is particularly frequent in accidents associated with third party liability insurance claims. The discrepancy between subjective complaints and the presence of objective findings is a particular challenge for the assessment by the medical expert.

Mechanisms of prey division in striped marlin, a marine group hunting predator

Many terrestrial group-hunters cooperate to kill prey but then compete for their share with dominance being a strong predictor of prey division. In contrast, little is known about prey division in group-hunting marine predators that predominately attack small, evasive prey (e.g. fish schools). We identified individual striped marlin (Kajikia audax) hunting in groups. Groups surrounded prey but individuals took turns attacking. We found that competition for prey access led to an unequal division of prey among the predators, with 50% of the most frequently attacking marlin capturing 70–80% of the fish. Neither aggression, body size nor variation in hunting efficiency explained this skewed prey division. We did find that newly arrived groups of marlin gained on average more access to the prey. This raises the possibility that newly arrived marlin were hungrier and more motivated to feed. However, this result does not necessarily explain the unequal prey division among the predators because the skew in prey captures was found at the level of these groups. Dynamic prey division is probably widespread but under-reported in marine group-hunters and the inability of individuals to monopolize prey until satiation likely reduces the importance of social hierarchies for prey division.

Striped marlin use a dynamic prey division method when hunting as a group, taking turns to feed but without doing so equally.

HCV cure: an appropriate moment to reduce cannabis use in people living with HIV? (ANRS CO13 HEPAVIH data)

BACKGROUND

Thanks to direct-acting antivirals, hepatitis C virus (HCV) infection can be cured, with similar rates in HCV-infected and HIV-HCV co-infected patients. HCV cure is likely to foster behavioral changes in psychoactive substance use, which is highly prevalent in people living with HIV (PLWH). Cannabis is one substance that is very commonly used by PLWH, sometimes for therapeutic purposes. We aimed to identify correlates of cannabis use reduction following HCV cure in HIV-HCV co-infected cannabis users and to characterize persons who reduced their use.

METHODS

We used data collected on HCV-cured cannabis users in a cross-sectional survey nested in the ANRS CO13 HEPAVIH cohort of HIV-HCV co-infected patients, to perform logistic regression, with post-HCV cure cannabis reduction as the outcome, and socio-behavioral characteristics as potential correlates. We also characterized the study sample by comparing post-cure substance use behaviors between those who reduced their cannabis use and those who did not.

RESULTS

Among 140 HIV-infected cannabis users, 50 and 5 had reduced and increased their use, respectively, while 85 had not changed their use since HCV cure. Cannabis use reduction was significantly associated with tobacco use reduction, a decrease in fatigue level, paying more attention to one's dietary habits since HCV cure, and pre-HCV cure alcohol abstinence (p = 0.063 for alcohol use reduction).

CONCLUSIONS

Among PLWH using cannabis, post-HCV cure cannabis reduction was associated with tobacco use reduction, improved well-being, and adoption of healthy behaviors. The management of addictive behaviors should therefore be encouraged during HCV treatment.

Tissue-specific multi-omics analysis of atrial fibrillation

Genome-wide association studies (GWAS) for atrial fibrillation (AF) have uncovered numerous disease-associated variants. Their underlying molecular mechanisms, especially consequences for mRNA and protein expression remain largely elusive. Thus, refined multi-omics approaches are needed for deciphering the underlying molecular networks. Here, we integrate genomics, transcriptomics, and proteomics of human atrial tissue in a cross-sectional study to identify widespread effects of genetic variants on both transcript (cis-eQTL) and protein (cis-pQTL) abundance. We further establish a novel targeted trans-QTL approach based on polygenic risk scores to determine candidates for AF core genes. Using this approach, we identify two trans-eQTLs and five trans-pQTLs for AF GWAS hits, and elucidate the role of the transcription factor NKX2-5 as a link between the GWAS SNP rs9481842 and AF. Altogether, we present an integrative multi-omics method to uncover trans-acting networks in small datasets and provide a rich resource of atrial tissue-specific regulatory variants for transcript and protein levels for cardiovascular disease gene prioritization.

Human-Engineered Atrial Tissue for Studying Atrial Fibrillation

This chapter details the generation of atrial fibrin-based engineered heart tissue (EHT) in standard 24-well format as a 3D model for the human atrium. Compared to 2D cultivation, human-induced pluripotent stem cells (hiPSCs)-derived atrial cardiomyocytes demonstrated a higher degree of maturation in 3D format. Furthermore, we have demonstrated in previous work that the model displayed atrial characteristics in terms of contraction and gene expression patterns, electrophysiology, and pharmacological response. Here, we describe how to embed atrial cardiomyocytes differentiated from hiPSCs in a fibrin hydrogel to form atrial EHT attached to elastic silicone posts, allowing auxotonic contraction. In addition, we describe how force and other contractility parameters can be derived from these beating atrial EHTs by video-optical monitoring. The presented atrial EHT model is suitable to study chamber-specific mechanisms, drug effects and to serve for disease modeling.

Long-chain acylcarnitine 18:1 acutely increases human atrial myocardial contractility and arrhythmia susceptibility

Long-chain acylcarnitines (LCACs) are known to directly alter cardiac contractility and electrophysiology. However, the acute effect of LCACs on human cardiac function is unknown. We aimed to determine the effect of LCAC 18:1, which has been associated with cardiovascular disease, on the contractility and arrhythmia susceptibility of human atrial myocardium. Additionally, we aimed to assess how LCAC 18:1 alters Ca²⁺ influx and spontaneous Ca²⁺ release in vitro. Human right atrial trabeculae (n = 32) stimulated at 1 Hz were treated with LCAC 18:1 at a range of concentrations (1-25 µM) for a 45-min period. Exposure to the LCAC induced a dose-dependent positive inotropic effect on myocardial contractility (maximal 1.5-fold increase vs. control). At the 25 µM dose (n = 8), this was paralleled by an enhanced propensity for spontaneous contractions (50% increase). Furthermore, all LCAC 18:1 effects on myocardial function were reversed following LCAC 18:1 washout. In fluo-4-AM-loaded HEK293 cells, LCAC 18:1 dose dependently increased cytosolic Ca²⁺ influx relative to vehicle controls and the short-chain acylcarnitine C3. In HEK293 cells expressing ryanodine receptor (RyR2), this increased Ca²⁺ influx was linked to an increased propensity for RyR2-mediated spontaneous Ca²⁺ release events. Our study is the first to show that LCAC 18:1 directly and acutely alters human myocardial function and in vitro Ca²⁺ handling. The metabolite promotes proarrhythmic muscle contractions and increases contractility. The exploratory findings in vitro suggest that LCAC 18:1 increases proarrhythmic RyR2-mediated spontaneous Ca²⁺ release propensity. The direct effects of metabolites on human myocardial function are essential to understand cardiometabolic dysfunction.NEW & NOTEWORTHY For the first time, the fatty acid metabolite, long-chain acylcarnitine 18:1, is shown to acutely increase the arrhythmia susceptibility and contractility of human atrial myocardium. In vitro, this was linked to an influx of Ca²⁺ and an enhanced propensity for spontaneous RyR2-mediated Ca²⁺ release.

Hypertrophic signaling compensates for contractile and metabolic consequences of DNA methyltransferase 3A loss in human cardiomyocytes

The role of DNA methylation in cardiomyocyte physiology and cardiac disease remains a matter of controversy. We have recently provided evidence for an important role of DNMT3A in human cardiomyocyte cell homeostasis and metabolism, using engineered heart tissue (EHT) generated from human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes carrying a knockout of the de novo DNA methyltransferase DNMT3A. Unlike isogenic control EHT, knockout EHT displayed morphological abnormalities such as lipid accumulations inside cardiomyocytes associated with impaired mitochondrial metabolism, as well as functional defects and impaired glucose metabolism. Here, we analyzed the role of DNMT3A in the setting of cardiac hypertrophy. We induced hypertrophic signaling by treatment with 50 nM endothelin-1 and 20 μM phenylephrine for one week and assessed EHT contractility, morphology, DNA methylation, and gene expression. While both knockout EHTs and isogenic controls showed the expected activation of the hypertrophic gene program, knockout EHTs were protected from hypertrophy-related functional impairment. Conversely, hypertrophic treatment prevented the metabolic consequences of a loss of DNMT3A, i.e. abolished lipid accumulation in cardiomyocytes likely by partial normalization of mitochondrial metabolism and restored glucose metabolism and metabolism-related gene expression of knockout EHT. Together, these data suggest an important role of DNA methylation not only for cardiomyocyte physiology, but also in the setting of cardiac disease.

Oil gland and oil pores in billfishes: in search of a function

Billfishes are well known for their distinctive elongated rostra, i.e. bills. The functional significance of billfish rostra has been frequently discussed and the recent discovery of an oil gland (glandula oleofera) at the base of the rostrum in swordfish, Xiphias gladius, has added an interesting facet to this discussion regarding the potential co-evolution of gland and rostra. Here, we investigated the oil gland and oil pores (through which the oil is brought to the skin surface) of four billfish species - swordfish, Atlantic blue marlin (Makaira nigricans), Indo-Pacific sailfish (Istiophorus platypterus) and striped marlin (Kajikia audax) - and provide detailed evidence for the presence of an oil gland in the last three. All four species had a high density of oil pores on the forehead which is consistent with the hypothesis of hydrodynamic benefits of the oil. The extension of the pores onto the front half of the rostrum in sailfish and striped marlin, but not in swordfish or blue marlin, suggests that the oil may have additional functions. One such function could be linked to the antibacterial and anti-inflammatory properties of the oil. However, the available evidence on predatory rostrum use (and hence the likelihood of tissue damage) is only partly consistent with the extension of pores on rostra across species. We conclude that the oil gland probably serves multiple, non-mutually exclusive functions. More detailed information on rostrum use in blue marlin and swordfish is needed to better link behavioural and morphological data with the aim of accomplishing a full comparative analysis.

'TB or not TB': the conundrum of pre-European contact tuberculosis in the Pacific

Tuberculosis (TB) is a major global health threat, infecting one-third of the world's population. Despite this prominence, the age, origin and spread of the disease have been topics of contentious debate. Molecular studies suggest that Mycobacterium tuberculosis 'sensu stricto', the most common strain of TB infecting humans today, originated in Africa and from there spread into Europe and Asia. The M. tuberculosis strains most commonly found across the Pacific and the Americas today are most closely related to European strains, supporting a hypothesis that the disease only reached these regions relatively recently via European sailors or settlers. However, this hypothesis is inconsistent with palaeopathological evidence of TB-like lesions in human remains from across the Pacific that predate European contact. Similarly, genetic evidence from pre-European South American mummies challenges the notion of a European introduction of the disease into the Pacific. Here, we review the complex evidence for the age and origin of TB in the Pacific, and discuss key gaps in our knowledge and how these may be addressed. This article is part of the theme issue 'Insights into health and disease from ancient biomolecules'.

Long-Chain Acylcarnitines and Cardiac Excitation-Contraction Coupling: Links to Arrhythmias

A growing number of metabolomic studies have associated high circulating levels of the amphiphilic fatty acid metabolites, long-chain acylcarnitines (LCACs), with cardiovascular disease (CVD) risk. These studies show that plasma LCAC levels can be correlated with the stage and severity of CVD and with indices of cardiac hypertrophy and ventricular function. Complementing these recent clinical associations is an extensive body of basic research that stems mostly from the twentieth century. These works, performed in cardiomyocyte and multicellular preparations from animal and cell models, highlight stereotypical derangements in cardiac electrophysiology induced by exogenous LCAC treatment that promote arrhythmic muscle behavior. In many cases, this is coupled with acute inotropic modulation; however, whether LCACs increase or decrease contractility is inconclusive. Linked to the electromechanical alterations induced by LCAC exposure is an array of effects on cardiac excitation-contraction coupling mechanisms that overload the cardiomyocyte cytosol with Na⁺ and Ca²⁺ ions. The aim of this review is to revisit this age-old literature and collate it with recent findings to provide a pathophysiological context for the growing body of metabolomic association studies that link circulating LCACs with CVD.

An Important Role for DNMT3A-Mediated DNA Methylation in Cardiomyocyte Metabolism and Contractility

Supplemental Digital Content is available in the text.

Background:

DNA methylation acts as a mechanism of gene transcription regulation. It has recently gained attention as a possible therapeutic target in cardiac hypertrophy and heart failure. However, its exact role in cardiomyocytes remains controversial. Thus, we knocked out the main de novo DNA methyltransferase in cardiomyocytes, DNMT3A, in human induced pluripotent stem cells. Functional consequences of DNA methylation-deficiency under control and stress conditions were then assessed in human engineered heart tissue from knockout human induced pluripotent stem cell–derived cardiomyocytes.

Methods:

DNMT3A was knocked out in human induced pluripotent stem cells by CRISPR/Cas9gene editing. Fibrin-based engineered heart tissue was generated from knockout and control human induced pluripotent stem cell–derived cardiomyocytes. Development and baseline contractility were analyzed by video-optical recording. Engineered heart tissue was subjected to different stress protocols, including serum starvation, serum variation, and restrictive feeding. Molecular, histological, and ultrastructural analyses were performed afterward.

Results:

Knockout of DNMT3A in human cardiomyocytes had three main consequences for cardiomyocyte morphology and function: (1) Gene expression changes of contractile proteins such as higher atrial gene expression and lower MYH7/MYH6 ratio correlated with different contraction kinetics in knockout versus wild-type; (2) Aberrant activation of the glucose/lipid metabolism regulator peroxisome proliferator-activated receptor gamma was associated with accumulation of lipid vacuoles within knockout cardiomyocytes; (3) Hypoxia-inducible factor 1α protein instability was associated with impaired glucose metabolism and lower glycolytic enzyme expression, rendering knockout-engineered heart tissue sensitive to metabolic stress such as serum withdrawal and restrictive feeding.

Conclusion:

The results suggest an important role of DNA methylation in the normal homeostasis of cardiomyocytes and during cardiac stress, which could make it an interesting target for cardiac therapy.

A model-based analysis of the reactive transport behaviour of 37 trace organic compounds during field-scale bank filtration

Though bank filtration diminishes the loads of many trace organic compounds (TOrCs) present in the source water, still there is a wide uncertainty on the influence of local environmental conditions on biodegradation processes. This research addresses the fate and transport behaviour of 37 trace organic compounds at a bank filtration site in Germany over a relatively long-time span of six years. Using two-dimensional heat and reactive transport modelling in FEFLOW, TOrCs are classified according to their occurrence in bank filtration wells with a residence time of up to 4 months. We identify 12 persistent compounds, 20 reactive compounds and 5 transformation products formed during aquifer passage. Estimates of first-order biodegradation rate constants are given for six reactive compounds. Minimum biodegradation rate constants (i.e. maximum half-lives) are approximated for eight compounds only present in the surface water. For some compounds, a simple first-order degradation model did not yield satisfactory results and the behaviour appears to be more complex. Processes like sorption, redox- and/or temperature-dependent biodegradation and temperature-dependent desorption are suspected but incorporating these into the model was beyond the scope of this paper that provides an overview for many compounds. Results highlight the ability of the sub-surface to improve the water quality during bank filtration, yet at the same time show the persistence of several compounds in the aquifer.

[Primary and secondary prevention of skin cancer in rural areas : A cross-sectional study in the Bavarian Forest]

BACKGROUND

Skin cancer is the most common malignancy of the fair-skinned population worldwide. To reduce skin cancer's burden primary and secondary prevention are critical. However, various studies indicate an inadequate prevention behavior among rural populations.

OBJECTIVE

To examine the risk and prevention behavior with respect to skin cancer and to identify subgroups in rural areas with specific need for prevention efforts.

MATERIALS AND METHODS

In a cross-sectional study carried out in the first quarter of 2017, patients and their accompanying persons (≥18 years) were interviewed on the subject of primary and secondary prevention in waiting rooms of nondermatological medical practices in the Bavarian Forest, Germany. Data were collected using paper-based questionnaires. Associations were calculated using logistic regression models.

RESULTS

In all, 880 persons (57.7% women, mean age = 49.5 years) were included in the analysis, of whom 53.6% had undergone a skin cancer screening at least once before. Sunscreen was the most frequently used sun protection measure. Male sex and being 18-34 years of age were significantly associated with not using prevention measures (depending on the measure: odds ratio [OR]: 1.4-2.4 and 1.8-3.7, respectively). In addition, not using skin cancer screening was associated with UV exposure more than 6 h daily in summer (OR: 1.8, 95%-CI [confidence interval]: 1.14-2.97).

CONCLUSION

Future prevention strategies should increasingly focus on young adults, on men and people with high solar UV exposition particularly, to reduce the burden of skin cancer in rural areas.

Determination of Nitrate in Forages by Using Selective Ion Electrode: Collaborative Study

Each of 10 collaborating laboratories analyzed 4 blind duplicate pairs of forage samples for nitrate, by using a potentiometric method. Two forage controls and a 100 000 mg KNO3/L standard were also provided. Nitrate was extracted into an aqueous Al2(SO4)3 solution containing 70 mg KNO3/L and quantitated with a nitrate-selective electrode. Standards were prepared using extracting solution as diluent. Nitrate concentrations in forage samples ranged from <0.50 to 4.35% KNO3. Repeatability coefficients of variation (CV0) ranged from 1.74 to 3.61%, and reproducibility coefficients of variation (CV1) ranged from 6.92 to 7.66%. Mean recovery of a 0.55% KNO3 spike was 94.5%. The method has been adopted official first action.

Linking hunting weaponry to attack strategies in sailfish and striped marlin

Linking morphological differences in foraging adaptations to prey choice and feeding strategies has provided major evolutionary insights across taxa. Here, we combine behavioural and morphological approaches to explore and compare the role of the rostrum (bill) and micro-teeth in the feeding behaviour of sailfish (Istiophorus platypterus) and striped marlin (Kajikia audax) when attacking schooling sardine prey. Behavioural results from high-speed videos showed that sailfish and striped marlin both regularly made rostrum contact with prey but displayed distinct strategies. Marlin used high-speed dashes, breaking schools apart, often contacting prey incidentally or tapping at isolated prey with their rostra; while sailfish used their rostra more frequently and tended to use a slower, less disruptive approach with more horizontal rostral slashes on cohesive prey schools. Capture success per attack was similar between species, but striped marlin had higher capture rates per minute. The rostra of both species are covered with micro-teeth, and micro-CT imaging showed that species did not differ in average micro-tooth length, but sailfish had a higher density of micro-teeth on the dorsal and ventral sides of their rostra and a higher amount of micro-teeth regrowth, suggesting a greater amount of rostrum use is associated with more investment in micro-teeth. Our analysis shows that the rostra of billfish are used in distinct ways and we discuss our results in the broader context of relationships between morphological and behavioural feeding adaptations across species.

How to detect high-performing individuals and groups: Decision similarity predicts accuracy

Distinguishing between high- and low-performing individuals and groups is of prime importance in a wide range of high-stakes contexts. While this is straightforward when accurate records of past performance exist, these records are unavailable in most real-world contexts. Focusing on the class of binary decision problems, we use a combined theoretical and empirical approach to develop and test a approach to this important problem. First, we use a general mathematical argument and numerical simulations to show that the similarity of an individual's decisions to others is a powerful predictor of that individual's decision accuracy. Second, testing this prediction with several large datasets on breast and skin cancer diagnostics, geopolitical forecasting, and a general knowledge task, we find that decision similarity robustly permits the identification of high-performing individuals and groups. Our findings offer a simple, yet broadly applicable, heuristic for improving real-world decision-making systems.

[Is the Bavarian Population Open for Teledermatology? A Cross-Sectional Study in Rural and Urban Regions of Bavaria, Germany]

AIM

Teledermatology has a great potential to improve dermatologic care in rural regions. The aim of this study was to assess the willingness to use teledermatology in the rural population of Bavaria, Southern Germany, and to explore major concerns regarding teledermatology.

METHODS

The data of this cross-sectional study were collected both as part of a health survey conducted in the Bavarian forest region in Q1/2017 and as part of a follow-up survey (Q1/2018) of a running cohort study recruited at a Bavarian agricultural festival. Study participants were asked in a standardized questionnaire whether they would send pictures of skin rashes or other skin changes to their dermatologist via the internet, and if "no", why not.

RESULTS

Data on 1,116 participants living in Bavaria were analysed (mean age 50.2 years, 57.3% female, 80.4% living in rural regions). Of the whole sample, 36.6% were willing to use teledermatology. Women, older participants and participants living in rural regions were less open to the use of teledermatology. Major concerns regarding teledermatology were impersonality, doubts about the quality of the service and data safety and privacy concerns.

DISCUSSION

The willingness to use teledermatology in the rural population of Bavaria is still rather low. Before teledermatology can realise its full potential for improving health care in rural regions, the population needs to be educated about the functioning and the advantages of teledermatology, and data safety concerns need to be addressed.

Prevalence and treatment of allergies in rural areas of Bavaria, Germany: a cross-sectional study

BACKGROUND

There is a high prevalence of allergies in Germany, with approximately 20% of the population having at least one allergy and only about 10% of these being treated adequately. We conducted a cross-sectional study in a rural area of Bavaria (Southern Germany) to evaluate the prevalence of allergies and their treatment, because research regarding this topic is currently limited.

METHODS

Data were collected in 10 offices of non-dermatological doctors using a self-filled questionnaire to ask participants about allergies and treatment.

RESULTS

A total of 641 questionnaires were appropriate for analysis. The prevalence of allergies in the Bavarian countryside was higher than that reported for Germany (37.3% vs. 20.0%). Furthermore, almost a third (30.4%) of allergies were not treated at all. The most frequently consulted therapist was found to be a general practitioner.

CONCLUSIONS

Based on the study results, there is a need for prevention programs and establishment of treatments for certain allergies to minimize long-term health effects. Moreover, more studies are needed to analyze the prevalence of allergies in farmers who had a higher prevalence of allergies compared to previously reported prevalence in literature reviews.

TRIAL REGISTRATIONS

The study was approved by the ethical review committee of the Technical University Munich (EC number 548/16S).

Artificial Light at Night Affects Emergence from a Refuge and Space Use in Guppies

Artificial light at night (ALAN) is a major form of anthropogenic pollution. ALAN is well known to affect different behaviours during nighttime, when changes in light conditions often have immediate consequences for the trade-offs individuals experience. How ALAN affects daytime behaviours, however, has received far less attention. Here we studied how ALAN affected daytime personality traits and learning ability. We exposed Trinidadian guppies, Poecilia reticulata, for 10 weeks to different ALAN levels: bright light (24 hrs bright light, ~5,000 lx), dim light (12 hrs bright light; 12 hrs dim light, ~0.5 lx) and control (12 hrs bright light; 12 hrs dark). Afterwards, we tested how the treatments affected diurnal emergence from a refuge, space use, activity, sociability and the ability to memorize the location of companion fish. Individuals exposed to the light treatments (both dim and bright light) emerged quicker from a refuge and fish from the bright light treatment spent relatively more time in the open area of the arena. ALAN did not affect any of the other behaviours, although memory could not be tested since fish did not learn the companions' location. Our results demonstrate that ALAN, next to affecting nocturnal behaviours, can also affect key diurnal behavioural processes, associated with risk-taking.

Novel DNA Methylation Sites Influence GPR15 Expression in Relation to Smoking

Smoking is a major risk factor for cardiovascular diseases and has been implicated in the regulation of the G protein-coupled receptor 15 (GPR15) by affecting CpG methylation. The G protein-coupled receptor 15 is involved in angiogenesis and inflammation. An effect on GPR15 gene regulation has been shown for the CpG site CpG3.98251294. We aimed to analyze the effect of smoking on GPR15 expression and methylation sites spanning the GPR15 locus. DNA methylation of nine GPR15 CpG sites was measured in leukocytes from 1291 population-based individuals using the EpiTYPER. Monocytic GPR15 expression was measured by qPCR at baseline and five-years follow up. GPR15 gene expression was upregulated in smokers (beta (ß) = −2.699, p-value (p) = 1.02 × 10⁻⁷⁷) and strongly correlated with smoking exposure (ß = −0.063, p = 2.95 × 10⁻³⁴). Smoking cessation within five years reduced GPR15 expression about 19% (p = 9.65 × 10⁻⁵) with decreasing GPR15 expression over time (ß = 0.031, p = 3.81 × 10⁻⁶). Additionally, three novel CpG sites within GPR15 affected by smoking were identified. For CpG3.98251047, DNA methylation increased steadily after smoking cessation (ß = 0.123, p = 1.67 × 10⁻³) and strongly correlated with changes in GPR15 expression (ß = 0.036, p = 4.86 × 10⁻⁵). Three novel GPR15 CpG sites were identified in relation to smoking and GPR15 expression. Our results provide novel insights in the regulation of GPR15, which possibly linked smoking to inflammation and disease progression.

[Terms for the feeling of itching in the Bavarian dialect]

BACKGROUND

Pruritus can have many different causes and is a very subjective sensation. As dialects show a greater diversity of linguistic expressions than standard languages, the description of the sensation of pruritus in a dialect might carry additional information about the quality of pruritus.

METHOD

This cross-sectional study was carried out in Q1/2016 in the rural Bavarian Forest region in Bavaria, Germany. Participants were recruited in the waiting rooms of local doctors. They were asked to complete four sentences composed in the Bavarian dialect in which one word per sentence that signified the sensation of pruritus had been replaced by a blank space.

RESULTS

In total, the 1,007 participants (mean age 49.97 years, SD = 15.76; 58.2% female) named 2,870 expressions, 144 excluding duplicates. 98.7% of the expressions could be matched to 13 underlying terms. The most frequent ones were "jucken" ('to itch'', 59.5%), "brennen" ('to burn', 26.5%), "kribbeln" (no English equivalent, 1.1%), "kratzen" ('to scratch', 0.7%) and "beißen" ('to bite', 0.6%). The use of the different expressions was strongly situational: In 75% of the cases "brennen" ('to burn') was used in the context of contact to a stinging nettle (in German 'Brennnessel'). Two of the 13 expressions ("kribbeln" and "bitzeln", no English equivalents) were even used only in this scenario.

DISCUSSION

In the Bavarian dialect several different expressions for the sensation of pruritus exist. Although "jucken" ('to itch') is the most common expression for the sensation of pruritus, the German medical terms "Pruritus" ('pruritus') and "Juckreiz" ('itch') don't do justice to the situational use of expressions in the dialect.

Injury-mediated decrease in locomotor performance increases predation risk in schooling fish

The costs and benefits of group living often depend on the spatial position of individuals within groups and the ability of individuals to occupy preferred positions. For example, models of predation events for moving prey groups predict higher mortality risk for individuals at the periphery and front of groups. We investigated these predictions in sardine (Sardinella aurita) schools under attack from group hunting sailfish (Istiophorus platypterus) in the open ocean. Sailfish approached sardine schools about equally often from the front and rear, but prior to attack there was a chasing period in which sardines attempted to swim away from the predator. Consequently, all sailfish attacks were directed at the rear and peripheral positions of the school, resulting in higher predation risk for individuals at these positions. During attacks, sailfish slash at sardines with their bill causing prey injury including scale removal and tissue damage. Sardines injured in previous attacks were more often found in the rear half of the school than in the front half. Moreover, injured fish had lower tail-beat frequencies and lagged behind uninjured fish. Injuries inflicted by sailfish bills may, therefore, hinder prey swimming speed and drive spatial sorting in prey schools through passive self-assortment. We found only partial support for the theoretical predictions from current predator-prey models, highlighting the importance of incorporating more realistic predator-prey dynamics into these models.This article is part of the themed issue 'Physiological determinants of social behaviour in animals'.

Prevalence and clinical relevance of thyroid stimulating hormone receptor-blocking antibodies in autoimmune thyroid disease

The prevalence and clinical relevance of thyroid stimulating hormone (TSH) receptor (TSHR) blocking antibodies (TBAb) in patients with autoimmune thyroid disease (AITD) was investigated. Serum TBAb were measured with a reporter gene bioassay using Chinese hamster ovary cells. Blocking activity was defined as percentage inhibition of luciferase expression relative to induction with bovine TSH alone (cut-off 40% inhibition). All samples were measured for TSHR stimulatory antibody (TSAb) and TSHR binding inhibiting immunoglobulins (TBII). A total of 1079 unselected, consecutive patients with AITD and 302 healthy controls were included. All unselected controls were negative for TBAb and TSAb. In contrast, the prevalence of TBAb-positive patients with Hashimoto's thyroiditis and Graves' disease was 67 of 722 (9·3%) and 15 of 357 (4·2%). Of the 82 TBAb-positive patients, thirty-nine (48%), 33 (40%) and 10 (12%) were hypothyroid, euthyroid and hyperthyroid, respectively. Ten patients were both TBAb- and TSAb-positive (four hypothyroid, two euthyroid and four hyperthyroid). Thyroid-associated orbitopathy was present in four of 82 (4·9%) TBAb-positive patients, with dual TSHR antibody positivity being observed in three. TBAb correlated positively with TBII (r = 0·67, P < 0·001) and negatively with TSAb (r = -0·86, P < 0·05). The percentage of TBII-positive patients was higher the higher the level of inhibition in the TBAb assay. Of the TBAb-positive samples with  > 70% inhibition, 87% were TBII-positive. Functional TSHR antibodies impact thyroid status. TBAb determination is helpful in the evaluation and management of patients with AITD. The TBAb assay is a relevant and important tool to identify potentially reversible hypothyroidism.