Putting the August Krogh principle to work in developmental physiology

Phenomics as an approach to Comparative Developmental Physiology

The dynamic nature of developing organisms and how they function presents both opportunity and challenge to researchers, with significant advances in understanding possible by adopting innovative approaches to their empirical study. The information content of the phenotype during organismal development is arguably greater than at any other life stage, incorporating change at a broad range of temporal, spatial and functional scales and is of broad relevance to a plethora of research questions. Yet, effectively measuring organismal development, and the ontogeny of physiological regulations and functions, and their responses to the environment, remains a significant challenge. "Phenomics", a global approach to the acquisition of phenotypic data at the scale of the whole organism, is uniquely suited as an approach. In this perspective, we explore the synergies between phenomics and Comparative Developmental Physiology (CDP), a discipline of increasing relevance to understanding sensitivity to drivers of global change. We then identify how organismal development itself provides an excellent model for pushing the boundaries of phenomics, given its inherent complexity, comparably smaller size, relative to adult stages, and the applicability of embryonic development to a broad suite of research questions using a diversity of species. Collection, analysis and interpretation of whole organismal phenotypic data are the largest obstacle to capitalising on phenomics for advancing our understanding of biological systems. We suggest that phenomics within the context of developing organismal form and function could provide an effective scaffold for addressing grand challenges in CDP and phenomics.

HeartCV: a tool for transferrable, automated measurement of heart rate and heart rate variability in transparent animals

Heart function is a key component of whole-organismal physiology. Bioimaging is commonly, but not exclusively, used for quantifying heart function in transparent individuals, including early developmental stages of aquatic animals, many of which are transparent. However, a central limitation of many imaging-related methods is the lack of transferability between species, life-history stages and experimental approaches. Furthermore, locating the heart in mobile individuals remains challenging. Here, we present HeartCV: an open-source Python package for automated measurement of heart rate and heart rate variability that integrates automated localization and is transferrable across a wide range of species. We demonstrate the efficacy of HeartCV by comparing its outputs with measurements made manually for a number of very different species with contrasting heart morphologies. Lastly, we demonstrate the applicability of the software to different experimental approaches and to different dataset types, such as those corresponding to longitudinal studies.

The Relationship Between Psychological Quality Education and Mental Health Level of College Students by Educational Psychology

To enable all college students to have positive psychological quality and sound personalities, their potential should be fully realized, and their comprehensive ability should be improved to adapt to society. Empirical research is carried out by means of questionnaires, and the relationship between psychological quality education and the mental health level of college students is studied through correlation analysis and regression analysis. Firstly, the problems existing in college students’ psychological quality education are summarized from the perspective of educational psychology through questionnaires. Secondly, the data of college students’ psychological quality education and mental health level are collected, and the general situation and the relationship between college students’ psychological quality education and mental health level are analyzed and discussed by processing the existing data. The research results show that 51% of college students think that psychological quality education is only needed when there is a psychological problem; 47% of college students believe that the current educational content of the school’s psychological quality education focuses on the prevention and solution of students’ psychological problems; 83% of the students consider that the psychological quality education currently carried out by the college still adopts the more traditional teaching methods such as classroom lectures, psychological counseling and special lectures. In the process of predicting college students’ mental health level, psychological resilience plays a significant role, which can predict 21.1% of variables. Psychological resilience and optimism can jointly predict 26.4% of variables. These contents broaden the research field of college students’ psychological quality education, enrich the related research on it, and provide a reference for the intervention of college students’ psychological health in school situations.

Beyond the Chicken: Alternative Avian Models for Developmental Physiological Research

Biomedical research focusing on physiological, morphological, behavioral, and other aspects of development has long depended upon the chicken (Gallus gallus domesticus) as a key animal model that is presumed to be typical of birds and generally applicable to mammals. Yet, the modern chicken in its many forms is the result of artificial selection more intense than almost any other domesticated animal. A consequence of great variation in genotype and phenotype is that some breeds have inherent aberrant physiological and morphological traits that may show up relatively early in development (e.g., hypertension, hyperglycemia, and limb defects in the broiler chickens). While such traits can be useful as models of specific diseases, this high degree of specialization can color general experimental results and affect their translational value. Against this background, in this review we first consider the characteristics that make an animal model attractive for developmental research (e.g., accessibility, ease of rearing, size, fecundity, development rates, genetic variation, etc.). We then explore opportunities presented by the embryo to adult continuum of alternative bird models, including quail, ratites, songbirds, birds of prey, and corvids. We conclude by indicating that expanding developmental studies beyond the chicken model to include additional avian groups will both validate the chicken model as well as potentially identify even more suitable avian models for answering questions applicable to both basic biology and the human condition.

Dietary Exposure to Low Levels of Crude Oil Affects Physiological and Morphological Phenotype in Adults and Their Eggs and Hatchlings of the King Quail (Coturnix chinensis)

Despite the current knowledge of the devastating effects of external exposure to crude oil on animal mortality, the study of developmental, transgenerational effects of such exposure has received little attention. We used the king quail as an animal model to determine if chronic dietary exposure to crude oil in a parental population would affect morpho-physiological phenotypic variables in their immediate offspring generation. Adult quail were separated into three groups: (1) Control, and two experimental groups dietarily exposed for at least 3 weeks to (2) Low (800 PAH ng/g food), or (3) High (2,400 PAH ng/g food) levels of crude oil. To determine the parental influence on their offspring, we measured metabolic and respiratory physiology in exposed parents and in their non-exposed eggs and hatchlings. Body mass and numerous metabolic (e.g., O₂ consumption, CO₂ production) and respiratory (e.g., ventilation frequency and volume) variables did not vary between control and oil exposed parental groups. In contrast, blood PO₂, PCO₂, and SO₂ varied among parental groups. Notably, water loss though the eggshell was increased in eggs from High oil level exposed parents. Respiratory variables of hatchlings did not vary between populations, but hatchlings obtained from High oil-exposed parents exhibited lower capacities to maintain body temperature while exposed to a cooling protocol in comparison to hatchlings from Low- and Control-derived parents. The present study demonstrates that parental exposure to crude oil via diet impacts some aspects of physiological performance of the subsequent first (F₁) generation.

Linking structure and function in the vertebrate respiratory system: A tribute to August Krogh

High rates of pulmonary gas exchange require three things: 1) that gases at the contact surface of the lung's capillaries are replenished rapidly from the environment; 2) that this surface is large and thin; 3) that the capillaries are effectively perfused with blood. In spite of this uniform requirement, lungs have evolved complex and highly diverse architectures, but we have a poor understanding of the drivers of this diversity. Here, I briefly discuss some of the diversity in gross anatomical features directing airflow in avian and non-avian reptiles. I also review new insights into the cellular anatomy of the blood-gas barrier, which in mammals is composed of specialized endothelial as well as epithelial cells.