Autonomic nervous system and hypothalamic–pituitary–adrenal axis response to experimentally induced cold pain in adolescent non-suicidal self-injury – study protocol

Background: Adolescent non-suicidal self-injury (NSSI) is associated with altered sensitivity to experimentally induced pain. Adolescents engaging in NSSI report greater pain threshold and pain tolerance, as well as lower pain intensity and pain unpleasantness compared to healthy controls. The experience of pain is associated with reactivity of both the autonomic nervous system (ANS) and the hypothalamic–pituitary–adrenal (HPA) axis. However, previous research has not yet systematically addressed differences in the physiological response to experimentally induced pain comparing adolescents with NSSI and age- and sex-matched healthy controls. Methods/Design: Adolescents with NSSI and healthy controls undergo repeated painful stimulation with the cold pressor task. ANS activity is continuously recorded throughout the procedure to assess changes in heart rate and heart rate variability. Blood pressure is monitored and saliva is collected prior to and after nociceptive stimulation to assess levels of saliva cortisol. Discussion: The study will provide evidence whether lower pain sensitivity in adolescents with NSSI is associated with blunted physiological and endocrinological responses to experimentally induced pain compared to healthy controls. Extending on the existing evidence on altered pain sensitivity in NSSI, measured by self-reports and behavioural assessments, this is the first study to take a systematic approach in evaluating the physiological response to experimentally induced pain in adolescent NSSI. Trial Registration: Deutsche Register Klinischer Studien, Study ID: DRKS00007807 ; Trial Registration Date: 13.02.201

Insights into the developmental cycle of Protochlamydia amoebophila UWE25, an endosymbiont of free-living amoebae

Bakterien, die der obligat intrazellulären Familie Chlamydiales angehören, alternieren zwischen zwei Stadien, die verschiedene Funktionen im produktiven Lebenszyklus ausüben: Die infektiösen aber metabolisch inaktiven Elementarkörperchen (EBs) können extrazellulär überleben, während sich Retikularkörperchen (RBs) in den Wirtszellen vermehren, um nach Rückdifferenzierung zu Elementarkörperchen wieder freigesetzt zu werden. Als Reaktion auf sich verschlechternde Wachstumsbedingungen durch zum Beispiel Entzug essentieller Nährstoffe, treten die pathogenen Chlamydiaceae in ein reversibles Stadium ein, welches sich morphologisch von EBs und RBs unterscheidet, und als persistentes Stadium bekannt ist. In dieser Arbeit wurde der Entwicklungszyklus eines Vertreters der Chlamydia-ähnlichen Bakterien – nämlich Protochlamydia amoebophila UWE25 – in dem Wirt Acanthamoeba sp. phänotypisch charakterisiert. Dies wurde einerseits durch die Kombination von Fluoreszenz in situ Hybridisierung (FISH) mit dem Nukleinsäurefarbstoff DAPI ermöglicht, was vermutlich auf Grund unterschiedlicher metabolischer Aktivität von EBs und RBs eine grobe Differenzierung dieser zwei Formen erlaubte. Andererseits wurden die infektiösen Nachkommen eines Zyklus quantitativ erfasst, sodass letztendlich, mit Hilfe beider Ansätze, wichtige Ereignisse des Entwicklungszyklus beschrieben und zeitlich festgelegt werden konnten: So findet die erste Freisetzung von Bakterien zwischen dem dritten und vierten Tag nach der Infektion und bald nach der ersten Redifferenzierung zu EBs statt; die Replikation beginnt ungefähr 24 Stunden nach der Infektion und hat eine zunehmende Zahl von RBs zur Folge, die anschließend bis 72 Stunden nach der Infektion dominieren; 120 Stunden nach der Infektion wird der Zyklus asychron. Außerdem lassen die quantitativen Daten eine nicht-parasitische, stabile Beziehung zwischen Wirt und Endosymbiont vermuten, welche im Gegensatz zu dem Verwandten Parachlamydia sp. in erster Linie nicht lytisch für die Wirtsamöben zu sein scheint. Zusätzlich zu der Charakterisierung des etablierten biphasischen Lebenszyklus unter günstigen Bedingungen konnte gezeigt werden, dass der fünf-tägige Entzug von Eisen mittels des chelatbildenden Deferoxamin-Mesilats (DAM) das vermehrte Auftreten von morphologisch ungewöhnlichen protochlamydialen Formen hervorruft. Ohne weitere Kennzeichen der chlamydialen Persistenz für P. amoebophila demonstriert zu haben, kann jedoch über die Ausbildung von persistenten Formen dieses Organismus unter ungünstigen Bedingungen spekuliert werden.It is known for members of the obligate intracellular Chlamydiae to alternate between two stages that serve different functions during the productive life cycle: infectious but metabolically inert elementary bodies (EBs) are able to survive in an extracellular environment, while fragile reticulate bodies (RBs) replicate intracellularly before bacteria are released after re-differentiation to EBs. In response to deteriorating conditions such as depletion of essential nutrients, pathogenic Chlamydiaceae enter a reversible stage morphologically different from EBs and RBs and known as persistent forms. In this work, the developmental cycle of an environmental representative of Chlamydiae, namely Protochlamydia amoebophila UWE25, was phenotypically characterized in Acanthamoeba sp. as a host. By combining fluorescence in situ hybridization (FISH) with the nucleic acid stain DAPI, thereby facilitating rough differentiation between EBs and RBs based on differences in metabolic activity, and quantitative analysis of infectious progeny production, distinctive developmental events during a synchronized infection were described and linked to time: first release of bacteria was determined to occur between 3 and 4 days post infection soon after first RB-to-EB transition; replication starts around 24 hours post infection (hpi) and gives rise to an increasing number of RBs which are predominantly present from 24 to 72 hpi; the cycle was observed to become asynchronous 120 hpi. Moreover, quantitative data suggest a stable rather than a parasitic host-endosymbiont relationship, that – in contrast to the related Parachlamydia sp. – is primarily non-lytic for its amoebal host. In addition to the well-established biphasic life cycle under favourable conditions, iron deprivation could be visualized to cause elevated levels of morphologically aberrant protochlamydial forms after 5 days of iron chelation by deferoxamine mesylate (DAM). Without having demonstrated further hallmarks of chlamydial persistence to apply to P. amoebophila, observed aberrant endosymbionts could represent persistent forms that promote survival under unfavourable conditions

Attachment security and attention to facial emotional expressions in preschoolers: An eye‐tracking study

According to attachment theory, internal working models of attachment affect the way in which social and emotional information is processed. The current study examined this theoretical claim by investigating the association between attachment security and attention to facial emotional expressions in 5‐year‐old children. Attachment security was assessed on a representational level using an Attachment Story Completion Task. Children's attention to facial emotional expressions was measured during an eye‐tracking task. Gaze data (fixation duration) were collected during the presentation of pictures displaying five different facial emotional expressions (neutral, angry, fearful, sad, and happy) of unfamiliar persons. Moreover, the Emotionality‐Activity‐Sociability Temperament Inventory was used to control for children's temperament and was filled out by children's mothers. Regression analyses revealed that attachment security was a significant predictor of children's attention to neutral and sad expressions while controlling for age, gender, and temperament. Moreover, a t ‐test revealed that securely attached children looked longer at the fearful expression than insecurely attached children. These findings provide direct evidence that even on a basic perceptional level attachment security is a predictor of children's emotional information processing

Architecture and host interface of environmental chlamydiae revealed by electron cryotomography

Chlamydiae comprise important pathogenic and symbiotic bacteria that alternate between morphologically and physiologically different life stages during their developmental cycle. Using electron cryotomography, we characterize the ultrastructure of the developmental stages of three environmental chlamydiae: Parachlamydia acanthamoebae, Protochlamydia amoebophila and Simkania negevensis. We show that chemical fixation and dehydration alter the cell shape of Parachlamydia and that the crescent body is not a developmental stage, but an artefact of conventional electron microscopy. We further reveal type III secretion systems of environmental chlamydiae at macromolecular resolution and find support for a chlamydial needle-tip protein. Imaging bacteria inside their host cells by cryotomography for the first time, we observe marked differences in inclusion morphology and development as well as host organelle recruitment between the three chlamydial organisms, with Simkania inclusions being tightly enveloped by the host endoplasmic reticulum. The study demonstrates the power of electron cryotomography to reveal structural details of bacteria–host interactions that are not accessible using traditional methods

High‐Pressure Sintering of Rhombohedral Cr2S3 Using TZM Tools

The influence of sintering parameters on the physical properties and the chemical structure of rhombohedral Cr2S3 (rh‐Cr2S3) is investigated using high pressures and high temperatures. The densification of the powder is performed by applying the high‐pressure field‐assisted sintering technique/spark plasma sintering. Using a titanium–zirconium–molybdenum (TZM) alloy as sintering tool, it is possible to increase the magnitude of the applied pressure to several hundred MPa at temperatures as high as 1223 K. A relative density of up to 99.9% is achieved at a sintering temperature of 1223 K and a pressure of 395 MPa. The presence of phase‐pure rh‐Cr2S3 is proven by X‐ray diffraction analysis and transmission electron microscopy. The Seebeck coefficients of the self‐doped samples change drastically with the sintering temperatures ranging between −650 and −350 μV K−1. The densities and the thermal conductivities of the sintered samples increase with increasing sintering temperatures. The electrical conductivity is largely increased compared with the thermal conductivity potentially due to the current‐assisted high‐pressure sinterin

The Impact of Video-Based Microinterventions on Attitudes Toward Mental Health and Help Seeking in Youth: Web-Based Randomized Controlled Trial.

BACKGROUND Mental health (MH) problems in youth are prevalent, burdening, and frequently persistent. Despite the existence of effective treatment, the uptake of professional help is low, particularly due to attitudinal barriers. OBJECTIVE This study evaluated the effectiveness and acceptability of 2 video-based microinterventions aimed at reducing barriers to MH treatment and increasing the likelihood of seeking professional help in young people. METHODS This study was entirely web based and open access. The interventions addressed 5 MH problems: generalized anxiety disorder, depression, bulimia, nonsuicidal self-injury, and problematic alcohol use. Intervention 1 aimed to destigmatize and improve MH literacy, whereas intervention 2 aimed to induce positive outcome expectancies regarding professional help seeking. Of the 2435 participants who commenced the study, a final sample of 1394 (57.25%) participants aged 14 to 29 years with complete data and sufficient durations of stay on the video pages were randomized in a fully automated manner to 1 of the 5 MH problems and 1 of 3 conditions (control, intervention 1, and intervention 2) in a permuted block design. After the presentation of a video vignette, no further videos were shown to the control group, whereas a second, short intervention video was presented to the intervention 1 and 2 groups. Intervention effects on self-reported potential professional help seeking (primary outcome), stigma, and attitudes toward help seeking were examined using analyses of covariance across and within the 5 MH problems. Furthermore, we assessed video acceptability. RESULTS No significant group effects on potential professional help seeking were found in the total sample (F2,1385=0.99; P=.37). However, the groups differed significantly with regard to stigma outcomes and the likelihood of seeking informal help (F2,1385=3.75; P=.02). Furthermore, separate analyses indicated substantial differences in intervention effects among the 5 MH problems. CONCLUSIONS Interventions to promote help seeking for MH problems may require disorder-specific approaches. The study results can inform future research and public health campaigns addressing adolescents and young adults. TRIAL REGISTRATION German Clinical Trials Register DRKS00023110; https://drks.de/search/de/trial/DRKS00023110

Anaerobic sulfur oxidation underlies adaptation of a chemosynthetic symbiont to oxic-anoxic interfaces

Chemosynthetic symbioses occur worldwide in marine habitats, but comprehensive physiological studies of chemoautotrophic bacteria thriving on animals are scarce. Stilbonematinae are coated by thiotrophic Gammaproteobacteria. As these nematodes migrate through the redox zone, their ectosymbionts experience varying oxygen concentrations. However, nothing is known about how these variations affect their physiology. Here, by applying omics, Raman microspectroscopy, and stable isotope labeling, we investigated the effect of oxygen on “Candidatus Thiosymbion oneisti.” Unexpectedly, sulfur oxidation genes were upregulated in anoxic relative to oxic conditions, but carbon fixation genes and incorporation of (13)C-labeled bicarbonate were not. Instead, several genes involved in carbon fixation were upregulated under oxic conditions, together with genes involved in organic carbon assimilation, polyhydroxyalkanoate (PHA) biosynthesis, nitrogen fixation, and urea utilization. Furthermore, in the presence of oxygen, stress-related genes were upregulated together with vitamin biosynthesis genes likely necessary to withstand oxidative stress, and the symbiont appeared to proliferate less. Based on its physiological response to oxygen, we propose that “Ca. T. oneisti” may exploit anaerobic sulfur oxidation coupled to denitrification to proliferate in anoxic sand. However, the ectosymbiont would still profit from the oxygen available in superficial sand, as the energy-efficient aerobic respiration would facilitate carbon and nitrogen assimilation. IMPORTANCE Chemoautotrophic endosymbionts are famous for exploiting sulfur oxidization to feed marine organisms with fixed carbon. However, the physiology of thiotrophic bacteria thriving on the surface of animals (ectosymbionts) is less understood. One longstanding hypothesis posits that attachment to animals that migrate between reduced and oxic environments would boost sulfur oxidation, as the ectosymbionts would alternatively access sulfide and oxygen, the most favorable electron acceptor. Here, we investigated the effect of oxygen on the physiology of “Candidatus Thiosymbion oneisti,” a gammaproteobacterium which lives attached to marine nematodes inhabiting shallow-water sand. Surprisingly, sulfur oxidation genes were upregulated under anoxic relative to oxic conditions. Furthermore, under anoxia, the ectosymbiont appeared to be less stressed and to proliferate more. We propose that animal-mediated access to oxygen, rather than enhancing sulfur oxidation, would facilitate assimilation of carbon and nitrogen by the ectosymbiont

Differential regulation of degradation and immune pathways underlies adaptation of the ectosymbiotic nematode Laxus oneistus to oxic-anoxic interfaces

Eukaryotes may experience oxygen deprivation under both physiological and pathological conditions. Because oxygen shortage leads to a reduction in cellular energy production, all eukaryotes studied so far conserve energy by suppressing their metabolism. However, the molecular physiology of animals that naturally and repeatedly experience anoxia is underexplored. One such animal is the marine nematode Laxus oneistus. It thrives, invariably coated by its sulfur-oxidizing symbiont Candidatus Thiosymbion oneisti, in anoxic sulfidic or hypoxic sand. Here, transcriptomics and proteomics showed that, whether in anoxia or not, L. oneistus mostly expressed genes involved in ubiquitination, energy generation, oxidative stress response, immune response, development, and translation. Importantly, ubiquitination genes were also highly expressed when the nematode was subjected to anoxic sulfidic conditions, together with genes involved in autophagy, detoxification and ribosome biogenesis. We hypothesize that these degradation pathways were induced to recycle damaged cellular components (mitochondria) and misfolded proteins into nutrients. Remarkably, when L. oneistus was subjected to anoxic sulfidic conditions, lectin and mucin genes were also upregulated, potentially to promote the attachment of its thiotrophic symbiont. Furthermore, the nematode appeared to survive oxygen deprivation by using an alternative electron carrier (rhodoquinone) and acceptor (fumarate), to rewire the electron transfer chain. On the other hand, under hypoxia, genes involved in costly processes (e.g., amino acid biosynthesis, development, feeding, mating) were upregulated, together with the worm’s Toll-like innate immunity pathway and several immune effectors (e.g., bactericidal/permeability-increasing proteins, fungicides). In conclusion, we hypothesize that, in anoxic sulfidic sand, L. oneistus upregulates degradation processes, rewires the oxidative phosphorylation and reinforces its coat of bacterial sulfur-oxidizers. In upper sand layers, instead, it appears to produce broad-range antimicrobials and to exploit oxygen for biosynthesis and development