Buffering and the evolution of chromosome-wide gene regulation

Copy number variation (CNV) in terms of aneuploidies of both entire chromosomes and chromosomal segments is an important evolutionary driving force, but it is inevitably accompanied by potentially problematic variations in gene doses and genomic instability. Thus, a delicate balance must be maintained between mechanisms that compensate for variations in gene doses (and thus allow such genomic variability) and selection against destabilizing CNVs. In Drosophila, three known compensatory mechanisms have evolved: a general segmental aneuploidy-buffering system and two chromosome-specific systems. The two chromosome-specific systems are the male-specific lethal complex, which is important for dosage compensation of the male X chromosome, and Painting of fourth, which stimulates expression of the fourth chromosome. In this review, we discuss the origin and function of buffering and compensation using Drosophila as a model

Ape Conservation Physiology: Fecal Glucocorticoid Responses in Wild Pongo pygmaeus morio following Human Visitation

Nature-based tourism can generate important revenue to support conservation of biodiversity. However, constant exposure to tourists and subsequent chronic activation of stress responses can produce pathological effects, including impaired cognition, growth, reproduction, and immunity in the same animals we are interested in protecting. Utilizing fecal samples (N = 53) from 2 wild habituated orangutans (Pongo pygmaeus morio) (in addition to 26 fecal samples from 4 wild unhabituated orangutans) in the Lower Kinabatangan Wildlife Sanctuary of Sabah, Malaysian Borneo, we predicted that i) fecal glucocorticoid metabolite concentrations would be elevated on the day after tourist visitation (indicative of normal stress response to exposure to tourists on the previous day) compared to samples taken before or during tourist visitation in wild, habituated orangutans, and ii) that samples collected from habituated animals would have lower fecal glucocorticoid metabolites than unhabituated animals not used for tourism. Among the habituated animals used for tourism, fecal glucocorticoid metabolite levels were significantly elevated in samples collected the day after tourist visitation (indicative of elevated cortisol production on the previous day during tourist visitation). Fecal glucocorticoid metabolite levels were also lower in the habituated animals compared to their age-matched unhabituated counterparts. We conclude that the habituated animals used for this singular ecotourism project are not chronically stressed, unlike other species/populations with documented permanent alterations in stress responses. Animal temperament, species, the presence of coping/escape mechanisms, social confounders, and variation in amount of tourism may explain differences among previous experiments. Acute alterations in glucocorticoid measures in wildlife exposed to tourism must be interpreted conservatively. While permanently altered stress responses can be detrimental, preliminary results in these wild habituated orangutans suggest that low levels of predictable disturbance can likely result in low physiological impact on these animals

The psychology of passion: A meta-analytical review of a decade of research on intrapersonal outcomes

It is just over a decade since Vallerand et al. (J Personal Soc Psychol 85:756–767, 2003) introduced the dualistic model of passion. In this study, we conduct a meta-analytical review of relationships between Vallerand et al’s two passions (viz. harmonious and obsessive), and intrapersonal outcomes, and test the moderating role of age, gender, domain, and culture. A systematic literature search yielded 94 studies, within which 27 criterion variables were reported. These criterion variables derived from four research areas within the intrapersonal sphere: (a) well-/ill-being, (b) motivation factors, (c) cognitive outcomes and, (d) behaviour and performance. From these areas we retrieved 1308 independent effect sizes and analysed them using random-effects models. Results showed harmonious passion positively corresponded with positive intrapersonal outcomes (e.g., positive affect, flow, performance). Obsessive passion, conversely, showed positive associations with positive and negative

Epigenetic engineering shows that a human centromere resists silencing mediated by H3K27me3/K9me3

Centromeres are characterized by the centromere-specific H3 variant CENP-A, which is embedded in chromatin with a pattern characteristic of active transcription that is required for centromere identity. It is unclear how centromeres remain transcriptionally active despite being flanked by repressive pericentric heterochromatin. To further understand centrochromatin’s response to repressive signals, we nucleated a Polycomb-like chromatin state within the centromere of a human artificial chromosome (HAC) by tethering the methyltransferase EZH2. This led to deposition of the H3K27me3 mark and PRC1 repressor binding. Surprisingly, this state did not abolish HAC centromere function or transcription, and this apparent resistance was not observed on a noncentromeric locus, where transcription was silenced. Directly tethering the reader/repressor PRC1 bypassed this resistance, inactivating the centromere. We observed analogous responses when tethering the heterochromatin Editor Suv39h1-methyltransferase domain (centromere resistance) or reader HP1α (centromere inactivation), respectively. Our results reveal that the HAC centromere can resist repressive pathways driven by H3K9me3/H3K27me3 and may help to explain how centromeres are able to resist inactivation by flanking heterochromatin

Clinical decision-making on spinal cord injury-associated pneumonia: a nationwide survey in Germany

Study design: Survey study. Objectives: Spinal cord injury (SCI)-associated pneumonia (SCI-AP) is associated with poor functional recovery and a major cause of death after SCI. Better tackling SCI-AP requires a common understanding on how SCI-AP is defined. This survey examines clinical algorithms relevant for diagnosis and treatment of SCI-AP. Setting: All departments for SCI-care in Germany. Methods: The clinical decision-making on SCI-AP and the utility of the Centers for Disease Control and Prevention (CDC) criteria for diagnosis of ‘clinically defined pneumonia’ were assessed by means of a standardized questionnaire including eight case vignettes of suspected SCI-AP. The diagnostic decisions based on the case information were analysed using classification and regression trees (CART). Results: The majority of responding departments were aware of the CDC-criteria (88%). In the clinical vignettes, 38–81% of the departments diagnosed SCI-AP in accordance with the CDC-criteria and 7–41% diagnosed SCI-AP in deviation from the CDC-criteria. The diagnostic agreement was not associated with the availability of standard operating procedures for SCI-AP management in the departments. CART analysis identified radiological findings, fever, and worsened gas exchange as most important for the decision on SCI-AP. Frequently requested supplementary diagnostics were microbiological analyses, C-reactive protein, and procalcitonin. For empirical antibiotic therapy, the departments used (acyl-)aminopenicillins/β-lactamase inhibitors, cephalosporins, or combinations of (acyl-)aminopenicillins/β-lactamase inhibitors with fluoroquinolones or carbapenems. Conclusions: This survey reveals a diagnostic ambiguity regarding SCI-AP despite the awareness of CDC-criteria and established SOPs. Heterogeneous clinical practice is encouraging the development of disease-specific guidelines for diagnosis and management of SCI-AP