Ediacara growing pains: Modular addition and development in Dickinsonia costata.
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ABSTRACT:
SUBMITTER: Evans SD
PROVIDER: S-EPMC8740542 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The Ediacara Biota represents the oldest fossil evidence for the appearance of animals but linking these taxa to specific clades has proved challenging. Dickinsonia is an abundant, apparently bilaterally symmetrical Ediacara fossil with uncertain affinities. We identified and measured key morphological features of over 900 specimens of Dickinsonia costata from the Ediacara Member, South Australia to characterize patterns in growth and morphology. Here we show that development in Dickinsonia costata was surprisingly highly regulated to maintain an ovoid shape via terminal addition and the predictable expansion of modules. This result, along with other characters found in Dickinsonia suggests that it does not belong within known animal groups, but that it utilized some of the developmental gene networks of bilaterians, a result predicted by gene sequencing of basal metazoans but previously unidentified in the fossil record. Dickinsonia thus represents an extinct clade located between sponges and the last common ancestor of Protostomes and Deuterostomes, and likely belongs within the Eumetazoa.
| S-EPMC5435172 | biostudies-literature
Project description:The ability to perceive and avoid harmful substances or stimuli is key to an organism's survival. The neuronal cognate of the perception of pain is known as nociception, and the reflexive motion to avoid pain is termed the nocifensive response. As the nocifensive response is an ancient and evolutionarily conserved behavioral response to nociceptive stimuli, it is amenable to study in relatively simple and genetically tractable model systems such as Drosophila. Recent studies have taken advantage of the useful properties of Drosophila larvae to begin elucidating the neuronal connectivity and molecular machinery underlying the nocifensive response. However, these studies have primarily utilized the third-instar larval stage, and many mutations that potentially influence nociception survive only until earlier larval stages. Here we characterize the nocifensive responses of Drosophila throughout larval development and find dramatic changes in the nature of the behavior. Notably, we find that prior to the third instar, larvae are unable to perform the characteristic "corkscrew-like roll" behavior. Also, we identify an avoidance behavior consistent with a nocifensive response that is present immediately after larval hatching, representing a paradigm that may be useful in examining mutations with an early lethal phenotype.
| S-EPMC4209481 | biostudies-literature
Project description:The Ediacara biota include macroscopic, morphologically complex soft-bodied organisms that appear globally in the late Ediacaran Period (575-542 Ma). The physiology, feeding strategies, and functional morphology of the modular Ediacara organisms (rangeomorphs and erniettomorphs) remain debated but are critical for understanding their ecology and phylogeny. Their modular construction triggered numerous hypotheses concerning their likely feeding strategies, ranging from micro-to-macrophagus feeding to photoautotrophy to osmotrophy. Macrophagus feeding in rangeomorphs and erniettomorphs is inconsistent with their lack of oral openings, and photoautotrophy in rangeomorphs is contradicted by their habitats below the photic zone. Here, we combine theoretical models and empirical data to evaluate the feasibility of osmotrophy, which requires high surface area to volume (SA/V) ratios, as a primary feeding strategy of rangeomorphs and erniettomorphs. Although exclusively osmotrophic feeding in modern ecosystems is restricted to microscopic bacteria, this study suggests that (i) fractal branching of rangeomorph modules resulted in SA/V ratios comparable to those observed in modern osmotrophic bacteria, and (ii) rangeomorphs, and particularly erniettomorphs, could have achieved osmotrophic SA/V ratios similar to bacteria, provided their bodies included metabolically inert material. Thus, specific morphological adaptations observed in rangeomorphs and erniettomorphs may have represented strategies for overcoming physiological constraints that typically make osmotrophy prohibitive for macroscopic life forms. These results support the viability of osmotrophic feeding in rangeomorphs and erniettomorphs, help explain their taphonomic peculiarities, and point to the possible importance of earliest macroorganisms for cycling dissolved organic carbon that may have been present in abundance during Ediacaran times.
| S-EPMC2732876 | biostudies-literature
Project description:To assess whether the prevalence of growing pains varies with indicators of fatty acid exposure. Growing pains (limb pains of no obvious explanation) have been shown to be strongly linked to a family history of arthritis, and are thought to predict an increased risk of the development of arthritis in adulthood. Much has been made of the possibility of fatty acids, particularly the ω-3 fatty acids, playing a preventive role in the development of arthritis, but little research has been undertaken to determine whether such fatty acids might reduce the risk of growing pains. We aimed to assess whether the prevalence of growing pains varies with indicators of fatty acid exposures. Case-control study nested within a prospective longitudinal cohort comparing prenatal and postnatal diet, blood measures and variants in fatty acid desaturase (FADS) genes that influence the metabolism of fatty acids. Statistical analysis took account of factors such as gender, smoke exposure, maternal age and education, social class and parity. Avon Longitudinal Study of Parents & Children. All children born between 1 April 1991 and 31 December 1992 (approximately14 000) within the Avon area (only that part of Avon under the South-West Regional Health Authority). This project compared 1676 children who reported 'growing pains' at age 8 with 6155 with no such pain. Reported limb pains of no apparent origin. There was no indication that the affected children had diets that differed with regard to ω-3, plasma levels of fatty acids, or the FADS genetic variants. We also assessed fetal and infant exposure but neither maternal prenatal blood levels nor maternal dietary intake, or duration of breast feeding showed any significant relationships even after adjustment for confounders. Thus, there is no evidence that ω-3 fatty acid status protects against the development of growing pains in childhood.
| S-EPMC3432839 | biostudies-literature
Project description:Emerging adulthood (18-30 years), in the Western world, is often a time of identity development and exploration, focusing on areas of work, relationships and education. Individuals with chronic illnesses, such as chronic pain, may be more vulnerable to facing challenges during this time. This study aims to investigate the needs of young adults (YAs) attending a tertiary level National Health Service (NHS) Pain Management Programme (PMP) Service in the United Kingdom; exploring how these needs may translate on to clinical assessment and the delivery of rehabilitation interventions.This is a descriptive qualitative study influenced by phenomenological approaches. YA with a diagnosis of chronic pain were recruited and assigned to one of four focus groups facilitated by a clinical psychologist and occupational therapist. A semi-structured interview guide was used to help facilitate the group discussion.Qualitative analysis identified four key themes in understanding the needs of YAs with chronic pain: (1) thwarted opportunities, (2) peer separation, (3) perceived illness validity in the context of age and (4) dependency/parental enmeshment.The emerging adulthood literature provides a valuable framework for examining a normal developmental trajectory and highlights the relevance of age-related processes in YAs with chronic pain. The idealisation of opportunity and the role of perception in this developmental phase both appear relevant. It is significant that emotional stability is not yet established in emerging adulthood and links to unhelpful management strategies that may be differentiated from older populations are identified.
| S-EPMC5521350 | biostudies-other
Project description:Abstract Background Commonly applied diagnostic criteria for growing pains (GP) have evolved without determination by an authoritative representative body. GP and restless legs syndrome (RLS) share anatomical, distributional, temporal, and other clinical features and are associated in individuals over time, in families, and in population samples. In this study, we tested the hypothesis that GP, diagnosed by widely used criteria, is confounded by cases of painful restless legs syndrome (RLS‐Painful). Methods A twin family study of genetic influence and associations of GP using questionnaires was administered by Twins Research Australia. Twins (3–18 years; monozygous 503, dizygous 513), their oldest siblings, mothers, and fathers were randomly selected from the twin registry. Family members completed the questionnaires assessing lifetime prevalence of GP by commonly applied criteria and covariates including the history of iron deficiency and pediatric pain disorders. A GP‐Specific phenotype was defined as GP without urge to move the legs. We determined similarities in twin pairs for the GP and GP‐Specific phenotypes, family associations, and estimated familial and individual‐specific associations for each phenotype. Results Lifetime prevalence was one‐third lower for GP‐Specific than for GP among the twin and family members. Monozygous twin pairs were more similar than dizygous twin pairs for GP and for the derived GP‐Specific phenotype by three methods, consistent with genetic influence. There were familial associations, but the essential evidence for genetic influence was the twin‐cotwin data. GP was associated, in multivariable analyses, with migraine, headaches, recurrent abdominal pain, and iron deficiency, while GP‐Specific associations were limited to migraine and headaches. Conclusions GP is hybrid, one‐third of cases having symptoms and associations of RLS, necessarily RLS‐Painful. GP‐Specific (without symptoms and associations of RLS) could have a genetic etiology. We propose new criteria to facilitate etiological and therapeutic research. Growing pains, a highly prevalent primary pain disorder of childhood, has been associated with restless legs syndrome in individuals over time, in families and in population samples. This conundrum has been clarified by the evidence in this twin family study that growing pains, as previously defined, has been confounded by symptoms of restless legs syndrome. An exclusion clause of urge to move the legs has resulted in criteria for a purer phenotype which retains evidence of heritability.
| S-EPMC9189907 | biostudies-literature
Project description:This paper discusses lessons learned from a failed clinical trial investigating the use of a mobile application (app) to deliver a mindfulness intervention to middle-aged and older adults receiving services at a rehabilitation hospital in Ontario, Canada. A randomized controlled trial with 82 participants was planned, with the experimental group receiving access to a mindfulness app and a wait-list control group receiving access to the app after 4 weeks; however, the study could not be completed due to low recruitment rates. This implementation failure was considered from the perspective of the PARIHS framework. More specifically, Three key recruitment challenges were identified, and recommendations for future research provided. Firstly, the increasingly complex care needs of the study population appeared to influence eligibility; it would be beneficial for future research to consider adopting strategies to better understand the needs of the target population. Secondly, participants' stage of care and readiness of change likely negatively influenced compliance and retention in this study, and should be assessed in future research. Finally, a lack of clinician integration into the research team negatively impacted recruitment in this study; future studies should consider integrating direct service providers into the research team as this may increase buy-in and referral rates. The challenges and recommendations outlined can inform design and implementation of future studies in this area.
| S-EPMC8777278 | biostudies-literature
Project description:BackgroundPhysician engagement has become a key metric for healthcare leadership and is associated with better healthcare outcomes. However, engagement tends to be low and difficult to measure and improve. This study sought to efficiently characterize the professional cultural dynamics between physicians and administrators at an academic hospital and how those dynamics affect physician engagement.Materials and methodsA qualitative mixed methods analysis was completed in 6 weeks, consisting of a preliminary analysis of the hospital system's history that was used to purposefully recruit 20 physicians across specialties and 20 healthcare administrators across management levels for semi-structured interviews and observation. Participation rates of 77% (20/26) and 83% (20/24) were achieved for physicians and administrators, respectively. Cohorts consisted of equal numbers of men and women with experience ranging from 1 to 35 years within the organization. Field notes and transcripts were systematically analyzed using an iterative inductive-deductive approach. Emergent themes were presented and discussed with approximately 400 physicians and administrators within the organization to assess validity and which results were most meaningful.Results & discussionThis investigation indicated a professional cultural disconnect was undermining efforts to improve physician engagement. This disconnect was further complicated by a minority (10%) not believing an issue existed and conflicting connotations not readily perceived by participants who often offered similar solutions. Physicians and administrators felt these results accurately reflected their realities and used this information as a common language to plan targeted interventions to improve physician engagement. Limitations of the study included its cross-sectional nature with a modest sample size at a single institution.ConclusionsA qualitative mixed methods analysis efficiently identified professional cultural barriers within an academic hospital to serve as an institution-specific guide to improving physician engagement.
| S-EPMC6373942 | biostudies-literature
Project description:We have determined the time-resolved transcriptome of the model gram-positive organism B. subtilis during growth on rich medium. DNA microarrays were used to monitor gene transcription in 10-minute intervals at 40 consecutive timepoints. From the growth curve and a PCA analysis of all gene expression levels, we identified 4 distinct growth phases: a lag phase, an exponential growth phase, and very clearly separated early and late stationary growth phases
2011-10-31 | GSE19831 | GEO
Project description:The Ediacara Biota preserves the oldest fossil evidence of abundant, complex metazoans. Despite their significance, assigning individual taxa to specific phylogenetic groups has proved problematic. To better understand these forms, we identify developmentally controlled characters in representative taxa from the Ediacaran White Sea assemblage and compare them with the regulatory tools underlying similar traits in modern organisms. This analysis demonstrates that the genetic pathways for multicellularity, axial polarity, musculature, and a nervous system were likely present in some of these early animals. Equally meaningful is the absence of evidence for major differentiation of macroscopic body units, including distinct organs, localized sensory machinery or appendages. Together these traits help to better constrain the phylogenetic position of several key Ediacara taxa and inform our views of early metazoan evolution. An apparent lack of heads with concentrated sensory machinery or ventral nerve cords in such taxa supports the hypothesis that these evolved independently in disparate bilaterian clades.
| S-EPMC7934905 | biostudies-literature