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In human infants, the ability to show gaze alternations between an object of interest and another individual is considered fundamental to the development of complex social-cognitive abilities. Here we show that well-socialised dog puppies show gaze alternations in two contexts at an early age, 6-7 weeks. Thus, 69.4% of puppies in a novel object test and 45.59% of puppies during an unsolvable task alternated their gaze at least once between a person's face and the object. In both contexts, the frequency of gaze alternations was positively correlated with the duration of whimpering, supporting the communicative nature of puppies' gazing. Furthermore, the number of gaze alternations in the two contexts was correlated, indicating an underlying propensity for gazing at humans despite likely different motivations in the two contexts. Similar to humans, and unlike great apes or wolves, domestic dogs show gaze alternations from an early age if they are well-socialised. They appear to have a genetic preparedness to communicate with humans via gaze alternations early in ontogeny, but they may need close contact with humans for this ability to emerge, highlighting the interactive effects of domestication and environmental factors on behavioural development in dogs., (© 2024. The Author(s).)

Noise fears represent the most common behavioural problem in dogs. This manuscript provides an overview of diverse approaches for alleviating fear of noises in dogs and the supporting evidence. In the treatment of noise fears, both short-term solutions to prevent trauma or the deterioration of fear during unavoidable noise events and longer-term training need to be considered. Environmental management, the provision of incentives (food/play) during noise exposure, and, when indicated, anxiolytic medication, can safeguard dogs' welfare during noise events. Most "alternative" products (such as nutraceuticals, herbal remedies, pheromones, homeopathy, Bach flowers, and essential oils) are unlikely to be sufficient as monotherapy for noise fears, whereas there is good evidence for the efficacy of several anxiolytic medications. In the longer term, counterconditioning to real-life noises, relaxation training, and desensitisation/counterconditioning using noise recordings have been shown to improve fear of noises in dogs. Preventative training appears to be highly effective in preventing the development of noise fears in puppies and adult dogs.

A basic understanding of dog behaviour and emotion is relevant not only for professionals, such as veterinary personnel or dog trainers, but also for dog owners and for people with little contact with dogs. Information about dog behaviour and emotions is mostly conveyed verbally. This study explores whether definitions of dog behaviour and emotion are understood in such a way that they can be allocated to a descriptor (i.e., a label such as "fearful"), even by people with low background knowledge. If people can match descriptors to definitions, this suggests that the definitions are distinct enough and elicit mental representations of behaviour that can fit the label. Good agreement on the definitions is a prerequisite for the validity of the descriptors used; however, no study to date has tested this. A sample of 236 adults was asked to match descriptors of Qualitative Behaviour Assessment (QBA) for veterinary and shelter situations to their correct definitions, e.g., the descriptor "fearful" to its definition "dog may try to flee, hide or freeze; ears back". Matching was substantially above chance; nonetheless, the mean proportion of correct responses was only 50% (SD ± 16.6%) for the veterinary QBA set and 33% (SD ± 14.3%) for the shelter QBA set. Performance in the matching task was positively correlated with measures of experience with dogs. Taken together, the results suggest that descriptor-definition pairs used to describe dog behaviour need to be clearly defined to avoid misinterpretations when teaching laypeople how to interpret canine behaviour.

In animal research, automation of affective states recognition has so far mainly addressed pain in a few species. Emotional states remain uncharted territories, especially in dogs, due to the complexity of their facial morphology and expressions. This study contributes to fill this gap in two aspects. First, it is the first to address dog emotional states using a dataset obtained in a controlled experimental setting, including videos from (n = 29) Labrador Retrievers assumed to be in two experimentally induced emotional states: negative (frustration) and positive (anticipation). The dogs' facial expressions were measured using the Dogs Facial Action Coding System (DogFACS). Two different approaches are compared in relation to our aim: (1) a DogFACS-based approach with a two-step pipeline consisting of (i) a DogFACS variable detector and (ii) a positive/negative state Decision Tree classifier; (2) An approach using deep learning techniques with no intermediate representation. The approaches reach accuracy of above 71% and 89%, respectively, with the deep learning approach performing better. Secondly, this study is also the first to study explainability of AI models in the context of emotion in animals. The DogFACS-based approach provides decision trees, that is a mathematical representation which reflects previous findings by human experts in relation to certain facial expressions (DogFACS variables) being correlates of specific emotional states. The deep learning approach offers a different, visual form of explainability in the form of heatmaps reflecting regions of focus of the network's attention, which in some cases show focus clearly related to the nature of particular DogFACS variables. These heatmaps may hold the key to novel insights on the sensitivity of the network to nuanced pixel patterns reflecting information invisible to the human eye., (© 2022. The Author(s).)

The socialisation period in dog puppies is one of the most important periods determining behavioural development in dogs. Here, we aimed to test the effect of providing stimulation (beyond mere exposure) early during the socialisation period (approx. 3-6 weeks) on puppies' behaviour. Each of 12 litters (83 puppies) of various breeds was divided into a treatment and a control group. Between 3-6 weeks, the treatment group received age-appropriate "challenge" exercises (carefully graded noise exposure, novel objects, and problem-solving tasks) four times per week (total 12 times). The control group spent the same time with the trainer, who cuddled or played with the puppies. In a behaviour test at 6-7 weeks, two of four principal components, "social-startle" and "response to novelty", differed significantly between the groups. Treatment puppies were bolder towards the novel object, showed a reduced startle reaction, and recovered more quickly after a loud noise. Furthermore, they accomplished the problem-solving task faster and were more persistent during problem-solving than the control group. The control group showed a higher interest in a friendly stranger. It is a possibility that increased handling experienced by the control group had beneficial effects on their sociability. No long-term effects of the treatment were found, as determined by a validated dog personality questionnaire, available for 67 dogs at the age of six months. Likely, a continuation of the treatment over a longer time period would be necessary to obtain lasting effects, since the training took place only during the first third of the socialisation period.

The zebrafish germline is specified during early embryogenesis by inherited maternal RNAs and proteins collectively called germ plasm. Only the cells containing germ plasm will become part of the germline, whereas the other cells will commit to somatic cell fates. Therefore, proper localization of germ plasm is key for germ cell specification and its removal is crucial for the development of the soma. The molecular mechanism underlying this process in vertebrates is largely unknown. Here, we show that germ plasm localization in zebrafish is similar to that in Xenopus but distinct from Drosophila. We identified non muscle myosin II (NMII) and tight junction (TJ) components, such as ZO2 and claudin-d (Cldn-d) as interaction candidates of Bucky ball (Buc), which is the germ plasm organizer in zebrafish. Remarkably, we also found that TJ protein ZO1 colocalizes with germ plasm, and electron microscopy of zebrafish embryos uncovered TJ-like structures at the cleavage furrows where the germ plasm is anchored. In addition, injection of the TJ receptor Cldn-d produced extra germ plasm aggregates, whereas expression of a dominant-negative version inhibited germ plasm aggregate formation. Our findings support for the first time a role for TJs in germ plasm localization., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2022. Published by The Company of Biologists Ltd.)

Dogs are renowned for 'looking back' at humans when confronted with a problem, but it has been questioned whether this implies help-seeking or giving up. We tested 56 pet dogs from two breed groups (herding dogs and terriers) in a modified unsolvable task paradigm. One reward type (food or toy) was enclosed in a box, while the respective other reward was accessible. With both reward types, human-directed gazing in relation to the box was significantly positively correlated with interaction with the box, as long as an alternative was available. This suggests that both behaviours served to attain the unavailable reward and reflected individual motivation for the inaccessible vs the accessible reward. Furthermore, we varied whether the owner or the experimenter was responsible for handling the rewards. In the owner-responsible group, dogs rarely gazed at the experimenter. In the experimenter-responsible group, dogs preferentially directed box-related gazing (prior to or after looking at or interacting with the box) at the owner. Still, they gazed at the experimenter significantly longer than the owner-responsible group. Conversely, toy-related gazing was directed significantly more at the experimenter. Thus, dogs adjust their gazing behaviour according to the people's responsibility and their current goal (help-seeking vs play). Gaze duration did not differ between herding dogs and terriers. We conclude that dogs use gazing at humans' faces as a social problem-solving strategy, but not all gazing can be classified as such. Dogs' human-directed gazing is influenced by the social relationships with the persons, situational associations, and context (unsolvable problem vs play)., (© 2022. The Author(s).)

Behavioural reactions towards a dead conspecific have been observed rarely in wild canids and there is no documented scientific evidence of grief in pet dogs. A quantitative analysis of grief-related responses in both dogs and owners was conducted, using the validated online Mourning Dog Questionnaire. The survey was completed by 426 Italian adults who had owned at least two dogs, one of whom died while the other was still alive. This research aims to explore whether, how and what a dog may experience over the loss of a companion dog. Multiple logistic regression indicates that both a friendly or parental relationship between two dogs but also the fact that dogs used to share food and the owner's grief and anger are principal predictors of negative behavioural changes. According to dog owners' answers, the surviving dog after the death of the companion dog changed both in terms of activities ("playing", "sleeping", and "eating") and emotions (fearfulness), which occurred as a function of the quality of the relationship between the two animals. By contrast, the time the two dogs had spent together had no effect on the behaviours of surviving dog. Owner perceptions about their dog's reactions and emotions were not related to the memory or suffering of the event that tended to diminish over time. These findings indicate that a dog may show grief-related behavioural and emotional patterns when a close conspecific dies, with aspects of the latter possibly related to the owner's emotional status., (© 2022. The Author(s).)

Background: Complete Eats Rx is a fruit and vegetable prescription program designed to incentivize fruit and vegetable consumption among Supplemental Nutrition Assistance Program (SNAP) participants via $10 incentives distributed either weekly or per encounter to purchase fruits and vegetables at a mid-price supermarket chain in Washington State., Objective: To better understand SNAP participants' experience, and to determine perceived impacts and consequences of the program., Design: Qualitative analysis of nine photovoice sessions. Participants chose the topics for discussion. Sessions were audiorecorded and transcribed. Thematic content analysis was performed to identify key emergent themes using Atlas.ti., Setting: Spokane, Seattle, and Yakima, Washington., Participants: Twenty-six individuals who received a fruit and vegetable prescription within the past 6 months, 23 of whom attended all three photovoice sessions offered at their site. Participants were recruited from three participating health care or public health organizations in Spokane, Seattle, and Yakima, Washington., Analysis: Transcriptions were coded using inductive methods. Coded statements were organized into major themes. Coding structures and analysis were strengthened by iterative interactions between researchers., Results: Participants reported Complete Eats Rx was an important resource for families and improved food security, diet quality, and the ability to purchase healthy foods, including a greater variety of fruits and vegetables. Primary barriers to food security and fruit and vegetable consumption included limited geographic accessibility and the high cost of fruits and vegetables, exacerbated by other financial constraints such as rising housing costs. Participants reported supermarket checkout difficulty because of embarrassment, stigmatization, and inability to redeem incentives. The most frequently mentioned barrier to perceived program acceptability was having only one supermarket chain as the acceptor of the incentive., Conclusion: Partnering with supermarkets to accept fruit and vegetable incentives is a unique strategy to increase produce purchasing that can be adopted by other localities. Focus on geographic accessibility, appropriate price points, and positive shopping experiences via expansion to local grocers, improvements in staff interactions, and a transition to an electronic system may improve incentive redemption and usability., (Copyright © 2021 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.)

The inner brow raiser is a muscle movement that increases the size of the orbital cavity, leading to the appearance of so-called 'puppy dog eyes'. In domestic dogs, this expression was suggested to be enhanced by artificial selection and to play an important role in the dog-human relationship. Production of the inner brow raiser has been shown to be sensitive to the attentive stance of a human, suggesting a possible communicative function. However, it has not yet been examined whether it is sensitive to human presence. In the current study, we aimed to test whether the inner brow raiser differs depending on the presence or absence of an observer. We used two versions of a paradigm in an equivalent experimental setting in which dogs were trained to expect a reward; however, the presence/absence of a person in the test apparatus was varied. In the social context, a human facing the dog delivered the reward; in the non-social context, reward delivery was automatized. If the inner brow raiser has a communicative function and dogs adjust its expression to an audience, we expect it to be shown more frequently in the social context (when facing a person in the apparatus) than in the non-social context (when facing the apparatus without a person inside). The frequency of the inner brow raiser differed between the two contexts, but contrary to the prediction, it was shown more frequently in the non-social context. We further demonstrate that the inner brow raiser is strongly associated with eye movements and occurs independently in only 6% of cases. This result challenges the hypothesis that the inner brow raiser has a communicative function in dog-human interactions and suggests a lower-level explanation for its production, namely an association with eye movements., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Bremhorst, Mills, Stolzlechner, Würbel and Riemer.)

A high proportion of dogs and cats are fearful during veterinary visits, which in some cases may escalate into aggression. Here, we discuss factors that contribute to negative emotions in a veterinary setting and how these can be addressed. We briefly summarise the available evidence for the interventions discussed. The set-up of the waiting area (e.g., spatial dividers; elevated places for cat carriers), tailoring the examination and the treatment to the individual, considerate handling (minimal restraint when possible, avoiding leaning over or cornering animals) and offering high-value food or toys throughout the visit can promote security and, ideally, positive associations. Desensitisation and counterconditioning are highly recommended, both to prevent and address existing negative emotions. Short-term pain from injections can be minimised by using tactile and cognitive distractions and topical analgesics, which are also indicated for painful procedures such as ear cleanings. Recommendations for handling fearful animals to minimise aggressive responses are discussed. However, anxiolytics or sedation should be used whenever there is a risk of traumatising an animal or for safety reasons. Stress-reducing measures can decrease fear and stress in patients and consequently their owners, thus strengthening the relationship with the clients as well as increasing the professional satisfaction of veterinary staff.

A high proportion of pet dogs show fear-related behavioural problems, with noise fears being most prevalent. Nonetheless, few studies have objectively evaluated fear expression in this species. Using owner-provided video recordings, we coded behavioural expressions of pet dogs during a real-life firework situation at New Year's Eve and compared them to behaviour of the same dogs on a different evening without fireworks (control condition), using Wilcoxon signed ranks tests. A backwards-directed ear position, measured at the base of the ear, was most strongly associated with the fireworks condition (effect size: Cohen's d = 0.69). Durations of locomotion (d = 0.54) and panting (d = 0.45) were also higher during fireworks than during the control condition. Vocalisations (d = 0.40), blinking (d = 0.37), and hiding (d = 0.37) were increased during fireworks, but this was not significant after sequential Bonferroni correction. This could possibly be attributed to the high inter-individual variability in the frequency of blinking and the majority of subjects not vocalising or hiding at all. Thus, individual differences must be taken into account when aiming to assess an individual's level of fear, as relevant measures may not be the same for all individuals. Firework exposure was not associated with an elevated rate of other so-called 'stress signals', lip licking and yawning.

Sensory Processing Sensitivity (SPS) is a personality trait in humans characterised by a tendency to process information deeply, to be easily overstimulated, and to have strong emotional responses and an enhanced sensitivity to subtle stimuli. A trait similar to SPS has recently been identified in dogs ("canine Sensory Processing Sensitivity", cSPS). In children, this trait interacts with parenting factors to influence emotional and mental development, which in turn are linked to behaviour problems. Paralleling these findings in humans, we demonstrate that cSPS interacts with owner personality and use of aversive communication to influence the likelihood of behaviour problems in dogs. More behaviour problems were reported for more highly sensitive dogs per se, when there was a relative mismatch between owner and dog personality, and when use of "negative punishment" was reported. These findings indicate that a dog's personality might moderate how an individual is affected by environmental factors, particularly owner personality and communication style, emphasising the importance of considering individuality in prevention, development and treatment of behaviour problems in dogs.

When unexpectedly switched from a preferred to a less-preferred food reward, non-human animals may decrease consumption below that when only receiving the less-preferred reward - a successive negative contrast (SNC) effect. SNC has been proposed as an animal welfare indicator, however, to be effective it should show external validity; being demonstrable outside of highly standardized laboratory settings. We therefore investigated whether the SNC effect typically shown in laboratory rats was observed in owned (pet) rats from heterogeneous non-laboratory environments. Subjects (N = 14) were tested in a consummatory SNC paradigm with solid food rewards. "Shifted" rats received a high-value reward for 10 days (pre-shift), a low-value reward for six days (post-shift), then one additional day of high-value reward (re-shift). "Unshifted" rats always received the same low-value reward. "Shifted" rats consumed more food during pre-shift and re-shift trials, but ate less of the low-value food than "unshifted" animals in the post-shift trials - a SNC effect. This confirms the external validity of the SNC paradigm, extending reproducibility to outside the laboratory, indicating translatability across contexts, thus enhancing its potential use as a welfare indicator.

Facial expressions are considered sensitive indicators of emotional states in humans and many animals. Identifying facial indicators of emotion is a major challenge and little systematic research has been done in non-primate species. In dogs, such research is important not only to address fundamental and applied scientific questions but also for practical reasons, since many problem behaviours are assumed to have an emotional basis, e.g. aggression based on frustration. Frustration responses can occur in superficially similar contexts as the emotional state of positive anticipation. For instance, the anticipated delivery of a food reward may induce the state of positive anticipation, but over time, if the food is not delivered, this will be replaced by frustration. We examined dogs' facial expressions in contexts presumed to induce both positive anticipation and frustration, respectively, within a single controlled experimental setting. Using DogFACS, an anatomically-based method for coding facial expressions of dogs, we found that the "Ears adductor" action was more common in the positive condition and "Blink", "Lips part", "Jaw drop", "Nose lick", and "Ears flattener" were more common in the negative condition. This study demonstrates how differences in facial expression in emotionally ambiguous contexts may be used to help infer emotional states of different valence.

Sport horses need to fulfill high physical and psychological requirements during training and competition. These as well as certain conditions of modern husbandry may affect their wellbeing. Here we aimed to (1) evaluate effects of demographic and management factors as well as personality traits on stress reactivity of sport horses, (2) investigate if elite sport horses have elevated stress levels compared to amateur sport horses, and (3) assess whether different equestrian disciplines differentially influence equine adrenal cortex responsiveness. For this purpose, we visited 149 healthy elite (n = 94) and amateur (n = 54) sport horses in Switzerland and performed an adrenocorticotropic hormone (ACTH) stimulation test. Additionally, a person who was familiar with the horse completed a questionnaire about demographic and management factors and their horses' personality traits. Linear models were calculated to assess associations between the questionnaire data and salivary cortisol 60 (T60) and 90 (T90) minutes after ACTH stimulation. While the model at T90 was not significant, post-stimulatory cortisol after 60 minutes appears most informative in line with a previous study and was significantly affected by the breed and by three management factors: "number of riders", "hours spent outside" and "group housing" (adjusted r2 = 15%, p<0.001). Thoroughbred and Warmblood horses displayed an increased adrenal response compared to Franches-Montagnes horses. Horses with several riders had a less pronounced reaction than horses with one rider, and horses that spent more time outside had a decreased response compared to horses that were stabled most of the time. Horses living in groups showed higher post-stimulatory cortisol values than horses that were housed singly. However, no significant associations of cortisol responsiveness with personality traits were found, and neither the use as elite or as amateur sport horses nor the discipline had an effect on the cortisol response. This suggests that optimizing husbandry conditions may be more important for improving equine welfare than changing their use., Competing Interests: The authors have declared that no competing interests exist. As an equine private practitioner, MH owns an equine private practice called 'Pferdemedizin Hermann GmbH'. This commercial affiliation does not alter our adherence to PLOS ONE policies on sharing data and materials.

People often develop strong emotional connections with their dogs and consider them to be members of the family. The purpose of this study was to develop a novel validated tool, the Mourning Dog Questionnaire, to recognise and evaluate the mourning process in people who have lost a dog. The research model was based on a grid of five different questionnaires: the Pet Bereavement Questionnaire, the Lexington Attachment to Pets Scale, the Animal-Human Continuity Scale, the Positivity Scale, and the Testoni Death Representation Scale. The Italian version of the survey was posted on social networks. A sample of 369 Italian dog owners filled in the questionnaire (mean age ± SD 42.00 ± 10.70 years). Reliability indices were good for all instruments. The total scores of the five questionnaires correlated with each other. The results from the Mourning Dog Questionnaire support the negative view of life after the death of a pet and people's tendency to humanise their pet, since dog owners perceived animals no differently from humans in terms of emotions, needs and legal rights. Findings arising from the use of the Mourning Dog Questionnaire will help the implementation of rationality-based strategies to improve the wellbeing, resilience and quality of life of people in the world experiencing the loss of a pet., Competing Interests: The authors declare no conflict of interest.

Noise fears represent a highly prevalent welfare problem in dogs. An online survey was performed to explore severity and progression of firework fears in dogs, and relationships with demographics, health, behaviour problems and owners' training efforts to prevent or alleviate firework fears. Fifty-two percent of dogs in the sample (N = 1225) were at least partially affected by firework fears, and the majority developed a fear of fireworks in the first year of life, with a decreasing frequency of new occurrences up until seven years, and only few newly affected dogs beyond this age. While almost three-quarters of fearful dogs had recovered by the next morning following firework exposure, recovery took up to one day in 10%, up to one week in 12%, and several weeks or even months in >3%. Univariate analyses indicated a significant effect of breed group, age, sex, neuter status, origin and age at acquisition on severity of firework fears in dogs. However, binomial models including multiple predictors of presence/ absence of firework fears identified only age, breed group (mixed breeds being most affected), health problems, and an interaction between health problems and age as significant predictors. This discrepancy might be explained by collinearities of predictors and underlying differences between mixed-breed dogs and purebreds, such as mixed breeds being acquired from shelters more often and being neutered more often. Firework fears are highly correlated with fears of gunshots and thunder, and to a low extent with fears of other noises, but not with any other behavioural problems. Both improvement and deterioration of firework fears were frequently reported. While an early age of onset and breed differences point to a strong genetic contribution to firework fears, the data indicate that training puppies or non-fearful adults to associate the noise with positive stimuli is highly effective in preventing later development of firework fears., Competing Interests: The author has declared that no competing interests exist.

Objective: Previous studies have suggested alterations in the kynurenine pathway as a major link between cytokine and neurotransmitter abnormalities in psychiatric disorders. Most of these studies used a cross-sectional case-control study design. However, knowledge is still lacking regarding the stability over time of kynurenine pathway metabolites and the functionally related cytokines. Therefore, we studied the stability of cytokines and tryptophan (TRP) parameters over a period of 12 weeks., Methods: A total of 117 participants-39 with major depression, 27 with somatoform disorder, and 51 healthy controls were enrolled. Four evaluations, including blood withdrawal and psychometric testing, were performed over a period of 12 weeks. We used ELISA to measure interleukin (IL)-6, IL-1 receptor antagonist (RA) and tumor necrosis factor α (TNF α). High-performance liquid chromatography was used to analyze neurotransmitter variables, i.e. TRP, 5-hydroxyindoleacetic acid (5-HIAA), kynurenine (KYN), 3-OH-kynurenine (3-HK), and kynurenic acid (KYNA)., Results: We found no significant fluctuations of TRP, its metabolites (5-HIAA, KYN, KYNA, and 3-HK), or the cytokines (IL-1RA, IL-6, and TNF α) in any of the groups over the 12 weeks., Conclusion: To our knowledge, this is the first longitudinal study performed in psychiatric patients to verify the stability and consequently the reliability of the biological parameters we investigated. Our data indicate that TRP metabolites and cytokines are reliable biological parameters in psychiatric research because they do not fluctuate significantly over time.

Successive negative contrast (SNC) effects are changes in anticipatory or consummatory behaviour when animals unexpectedly receive a lower value reward than they have received previously. SNC effects are often assumed to reflect frustration and appear to be influenced by background affective state. However, alternative explanations of SNC, such as the functional-search hypothesis, do not necessarily imply an aversive affective state. We tested 18 dogs in a SNC paradigm using a patch foraging task. Dogs were tested in two conditions, once with the low value reward in all of five trials (unshifted) and once when reward value was altered between high and low (shifted). Following a reward downshift, subjects showed a SNC effect by switching significantly more often between patches compared to the unshifted condition. However, approach latency, foraging time and quantity consumed did not differ between conditions, suggesting non-affective functional search behaviour rather than frustration. There was no relationship between strength of SNC and anxiety-related behaviours as measured in a novel object test and a personality questionnaire (C-BARQ). However, associations with the C-BARQ scores for Trainability and Stranger directed aggression suggest a possible link with behavioural flexibility and coping style. While reward quality clearly affects incentive motivation, the relationship between SNC, frustration and background affective state requires further exploration.

The proteins Oskar (Osk) in Drosophila and Bucky ball (Buc) in zebrafish act as germ plasm organizers. Both proteins recapitulate germ plasm activities but seem to be unique to their animal groups. Here, we discover that Osk and Buc show similar activities during germ cell specification. Drosophila Osk induces additional PGCs in zebrafish. Surprisingly, Osk and Buc do not show homologous protein motifs that would explain their related function. Nonetheless, we detect that both proteins contain stretches of intrinsically disordered regions (IDRs), which seem to be involved in protein aggregation. IDRs are known to rapidly change their sequence during evolution, which might obscure biochemical interaction motifs. Indeed, we show that Buc binds to the known Oskar interactors Vasa protein and nanos mRNA indicating conserved biochemical activities. These data provide a molecular framework for two proteins with unrelated sequence but with equivalent function to assemble a conserved core-complex nucleating germ plasm., Competing Interests: The authors have declared that no competing interests exist.

Phase separation represents an important form of subcellular compartmentalization. However, relatively little is known about how the formation or disassembly of such compartments is regulated. In zebrafish, the Balbiani body (Bb) and the germ plasm (Gp) are intimately linked phase-separated structures essential for germ cell specification and home to many germ cell-specific mRNAs and proteins. Throughout development, these structures occur as a single large aggregate (Bb), which disperses throughout oogenesis and upon fertilization accumulates again into relatively large assemblies (Gp). Formation of the Bb requires Bucky ball (Buc), a protein with prion-like properties. We found that the multi-tudor domain-containing protein Tdrd6a interacts with Buc, affecting its mobility and aggregation properties. Importantly, lack of this regulatory interaction leads to significant defects in germ cell development. Our work presents insights into how prion-like protein aggregations can be regulated and highlights the biological relevance of such regulatory events., (Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.)

Recently, there has been a move towards positive reinforcement using food rewards in animal training. By definition, rewards function as reinforcers if they increase or maintain the frequency of behaviour that they follow. However, in operant conditioning tasks animals frequently show systematic changes in performance - in particular a reduction in responding over time. One suggested strategy to avoid such performance decrements is to provide a variety of food rewards, rather than the same food reward in all trials. The enhancement of appetitive behaviour and consumption by reward variation is referred to as 'variety effect'. We investigated whether dogs preferred a variable or a constant food reward in a concurrent two-choice test. Of 16 dogs, six subjects showed a significant preference for the varied food reward and six for the constant food reward, while four dogs exhibited no significant preference for either option. At the group level, there was a significant effect of block: preference for the varied food reward increased across six blocks of ten trials each. Thus, although some individuals may prefer a single, favourite food reward in the short term, introducing variation in reward types may maintain dogs' motivation in operant tasks over a longer time period.

Individual behavioural differences in pet dogs are of great interest from a basic and applied research perspective. Most existing dog personality tests have specific (practical) goals in mind and so focused only on a limited aspect of dogs' personality, such as identifying problematic (aggressive or fearful) behaviours, assessing suitability as working dogs, or improving the results of adoption. Here we aimed to create a comprehensive test of personality in pet dogs that goes beyond traditional practical evaluations by exposing pet dogs to a range of situations they might encounter in everyday life. The Vienna Dog Personality Test (VIDOPET) consists of 15 subtests and was performed on 217 pet dogs. A two-step data reduction procedure (principal component analysis on each subtest followed by an exploratory factor analysis on the subtest components) yielded five factors: Sociability-obedience, Activity-independence, Novelty seeking, Problem orientation, and Frustration tolerance. A comprehensive evaluation of reliability and validity measures demonstrated excellent inter- and intra-observer reliability and adequate internal consistency of all factors. Moreover the test showed good temporal consistency when re-testing a subsample of dogs after an average of 3.8 years-a considerably longer test-retest interval than assessed for any other dog personality test, to our knowledge. The construct validity of the test was investigated by analysing the correlations between the results of video coding and video rating methods and the owners' assessment via a dog personality questionnaire. The results demonstrated good convergent as well as discriminant validity. To conclude, the VIDOPET is not only a highly reliable and valid tool for measuring dog personality, but also the first test to show consistent behavioural traits related to problem solving ability and frustration tolerance in pet dogs.

Objective: Cellular immune status in major depression (MD) patients differs from that in somatoform disorder (SFD) patients and healthy controls (HC). It is still questionable whether the patterns of immune parameters remain stable over time. Therefore, we studied lymphocyte and monocyte cell counts and neopterin levels in peripheral blood of MD and SFD patients and HC over 12 weeks and tested for correlations between biochemical and psychometric parameters., Methods: Thirty-nine patients with MD, 27 with SFD, and 51 HC were recruited. Peripheral blood was drawn at four visits, at 4-week intervals. We assessed the total cell count of B lymphocytes, natural killer (NK) cells, T lymphocyte subpopu-lations, and monocytes by flow cytometry, and neopterin serum levels by ELISA. Psychometric parameters were measured with questionnaires., Results: Counts of lymphocytes, monocytes, and neopterin were stable in the SFD and HC groups. In the MD group, total CD3+, CD3+CD8+, NK cells, and CD3+CD25+ T cells showed inhomogeneous variances in Friedman tests, particularly in females. Neopterin correlated with depressed mood in MD patients, and with body mass index in HC., Conclusions: Cellular immune parameters are stable in HC and SFD. Our results may indicate influences of MD and gender on some cellular immune parameters. This may need to be considered in future immunological studies., (© 2018 S. Karger AG, Basel.)

Infrared thermography can visualize changes in body surface temperature that result from stress-induced physiological changes and alterations of blood flow patterns. Here we explored its use for remote stress monitoring (i.e. removing need for human presence) in a sample of six pet dogs. Dogs were tested in a brief separation test involving contact with their owner, a stranger, and social isolation for two one-minute-periods. Tests were filmed using a thermographic camera set up in a corner of the room, around 7m from where the subjects spent most of the time. Temperature was measured from selected regions of both ear pinnae simultaneously. Temperatures of both ear pinnae showed a pattern of decrease during separation and increase when a person (either the owner or a stranger) was present, with no lateralized temperature differences between the two ears. Long distance thermographic measurement is a promising technique for non-invasive remote stress assessment, although there are some limitations related to dogs' hair structure over the ears, making it unsuitable for some subjects., (Copyright © 2016 Elsevier Inc. All rights reserved.)