Century-long cod otolith biochronology reveals individual growth plasticity in response to temperature

Otolith biochronologies combine growth records from individual fish to produce long-term growth sequences, which can help to disentangle individual from population-level responses to environmental variability. This study assessed individual thermal plasticity of Atlantic cod (Gadus morhua) growth in Icelandic waters based on measurements of otolith increments. We applied linear mixed-effects models and developed a century-long growth biochronology (1908-2014). We demonstrated interannual and cohort-specific changes in the growth of Icelandic cod over the last century which were mainly driven by temperature variation. Temperature had contrasting relationships with growth-positive for the fish during the youngest ages and negative during the oldest ages. We decomposed the effects of temperature on growth observed at the population level into within-individual effects and among-individual effects and detected significant individual variation in the thermal plasticity of growth. Variance in the individual plasticity differed across cohorts and may be related to the mean environmental conditions experienced by the group. Our results underscore the complexity of the relationships between climatic conditions and the growth of fish at both the population and individual level, and highlight the need to distinguish between average population responses and growth plasticity of the individuals for accurate growth predictions

Digital consumer health: Negotiating multiple voices in the clinical consultation

In this paper, we explore what may happen when people who are ostensibly “well” bring data from digital self-tracking technologies to medical consultations. On the basis of a fictional case narrative, we explore how multiple “voices”, in a Bakhtinian sense of the term, inscribed in the self-tracking devices are activated, negotiated, evaluated and re-imagined in the context of care. The digital metrics “speak” precision, objectivity and urgency in ways that challenge conventional, normative understandings of doctors’ professional role and the patient-doctor relationship. Our theorizing is firmly grounded in our professional experience and informed by recent research on self-tracking, Mol’s research on the ways in which technology has become integral to medical care, Bakhtinian theory and medical professionalism, and it contributes to current professional debates regarding medical overuse and its potential to harm patients. Further research is needed to illuminate the consequences of digital self-tracking technologies for patient-professional consultations in practice

X-ray crystal structure of Vibrio alkaline phosphatase with the non-competitive inhibitor cyclohexylamine

Background - Para-nitrophenyl phosphate, the common substrate for alkaline phosphatase (AP), is available as a cyclohexylamine salt. Here, we report that cyclohexylamine is a non-competitive inhibitor of APs. Methods - Cyclohexylamine inhibited four different APs. Co-crystallization with the cold-active Vibrio AP (VAP) was performed and the structure solved. Results - Inhibition of VAP fitted a non-competitive kinetic model (Km unchanged, Vmax reduced) with IC50 45.3 mM at the pH optimum 9.8, not sensitive to 0.5 M NaCl, and IC50 27.9 mM at pH 8.0, where the addition of 0.5 M NaCl altered the inhibition to the level observed at pH 9.8. APs from E. coli and calf intestines were less sensitive to cyclohexylamine, whereas an Antarctic bacterial AP was similar to VAP in this respect. X-ray crystallography at 2.3 Å showed two binding sites, one in the active site channel and another at the surface close to dimer interface. Antarctic bacterial AP and VAP have Trp274 in common in their active-sites, that takes part in binding cyclohexylamine. VAP variants W274A, W274K, and W274H gave IC50 values of 179 mM, 188 mM and 187 mM, respectively, at pH 9.8. Conclusions - The binding of cyclohexylamine in locations at the dimeric interface and/or in the active site of APs may delay product release or reduce the rate of catalytic step(s) involving conformational changes and intersubunit communications. General significance - Cyclohexylamine is a common chemical in industries and used as a counterion in substrates for alkaline phosphatase, a clinically important and common enzyme in the biosphere