Soft robotics informs how an early echinoderm moved.

The transition from sessile suspension to active mobile detritus feeding in early echinoderms (c.a. 500 Mya) required sophisticated locomotion strategies. However, understanding locomotion adopted by extinct animals in the absence of trace fossils and modern analogues is extremely challenging. Here, we develop a biomimetic soft robot testbed with accompanying computational simulation to understand fundamental principles of locomotion in one of the most enigmatic mobile groups of early stalked echinoderms-pleurocystitids. We show that these Paleozoic echinoderms were likely able to move over the sea bottom by means of a muscular stem that pushed the animal forward (anteriorly). We also demonstrate that wide, sweeping gaits could have been the most effective for these echinoderms and that increasing stem length might have significantly increased velocity with minimal additional energy cost. The overall approach followed here, which we call "Paleobionics," is a nascent but rapidly developing research agenda in which robots are designed based on extinct organisms to generate insights in engineering and evolution.

Large euarthropod carapaces from a high latitude Cambrian (Drumian) deposit in Spain.

Deposits preserving non-biomineralized tissues and animals provide an unrivalled opportunity to study the evolution and radiation of early animal life. Numerous sites of Cambrian age are known from North America (Laurentia) and South China (East Gondwana), which provide a high resolution picture of the fauna at low latitudes. By contrast, our knowledge of Cambrian animals from higher latitudes is relatively poor. This patchiness in our knowledge of animal life during the radiation of animals in the Cambrian period limits our ability to understand and detect palaeogeographic trends and does not provide a full appreciation of animal diversity at this time. Here we report a new middle Cambrian (Drumian) site preserving lightly sclerotized euarthropod carapaces, sponges and palaeoscolecids near the village of Mesones de Isuela in the Iberian Chains (Spain). We describe three bivalved euarthropod carapace morphs, two comparable to those described from the only other high latitude Drumian deposit, the Jince Formation (Czechia), and one distinct from previous discoveries. These new findings highlight the importance of high latitude Gondwana Konservat Lagerstatten for understanding the palaeogeographical aspect of the radiation of early animals and suggest that bivalved euarthropods at high latitudes were larger than those at lower latitudes during the Cambrian.

Increased paclitaxel recovery from Taxus baccata vascular stem cells using novel in situ product recovery approaches.

In this study, several approaches were tested to optimise the production and recovery of the widely used anticancer drug Taxol® (paclitaxel) from culturable vascular stem cells (VSCs) of Taxus baccata, which is currently used as a successful cell line for paclitaxel production. An in situ product recovery (ISPR) technique was employed, which involved combining three commercial macro-porous resin beads (HP-20, XAD7HP and HP-2MG) with batch and semi-continuous cultivations of the T. baccata VSCs after adding methyl jasmonate (Me-JA) as an elicitor. The optimal resin combination resulted in 234 ± 23 mg of paclitaxel per kg of fresh-weight cells, indicating a 13-fold improved yield compared to the control (with no resins) in batch cultivation. This resin treatment was further studied to evaluate the resins' removal capacity of reactive oxygen species (ROS), which can cause poor cell growth or reduce product synthesis. It was observed that the ISPR cultivations had fourfold less intracellular ROS concentration than that of the control; thus, a reduced ROS concentration established by the resin contributed to increased paclitaxel yield, contrary to previous studies. These paclitaxel yields are the highest reported to date using VSCs, and this scalable production method could be applied for a diverse range of similar compounds utilising plant cell culture.

Cambrian edrioasteroid reveals new mechanism for secondary reduction of the skeleton in echinoderms.

Echinoderms are characterized by a distinctive high-magnesium calcite endoskeleton as adults, but elements of this have been drastically reduced in some groups. Herein, we describe a new pentaradial echinoderm, Yorkicystis haefneri n. gen. n. sp., which provides, to our knowledge, the oldest evidence of secondary non-mineralization of the echinoderm skeleton. This material was collected from the Cambrian Kinzers Formation in York (Pennsylvania, USA) and is dated as ca 510 Ma. Detailed morphological observations demonstrate that the ambulacra (i.e. axial region) are composed of flooring and cover plates, but the rest of the body (i.e. extraxial region) is preserved as a dark film and lacks any evidence of skeletal plating. Moreover, X-ray fluorescence analysis reveals that the axial region is elevated in iron. Based on our morphological and chemical data and on taphonomic comparisons with other fossils from the Kinzers Formation, we infer that the axial region was originally calcified, while the extraxial region was non-mineralized. Phylogenetic analyses recover Yorkicystis as an edrioasteroid, indicating that this partial absence of skeleton resulted from a secondary reduction. We hypothesize that skeletal reduction resulted from lack of expression of the skeletogenic gene regulatory network in the extraxial body wall during development. Secondary reduction of the skeleton in Yorkicystis might have allowed for greater flexibility of the body wall.

Evolution and Development at the Origin of a Phylum.

Quantifying morphological evolution is key to determining the patterns and processes underlying the origin of phyla. We constructed a hierarchical morphological character matrix to characterize the radiation and establishment of echinoderm body plans during the early Paleozoic. This showed that subphylum-level clades diverged gradually through the Cambrian, and the distinctiveness of the resulting body plans was amplified by the extinction of transitional forms and obscured by convergent evolution during the Ordovician. Higher-order characters that define these body plans were not fixed at the origin of the phylum, countering hypotheses regarding developmental processes governing the early evolution of animals. Instead, these burdened characters were flexible, enabling continued evolutionary innovation throughout the clades' history.

Assessing canalisation of intraspecific variation on a macroevolutionary scale: the case of crinoid arms through the Phanerozoic.

Clades that represent a new 'Bauplan' have been hypothesised to exhibit more variability than more derived clades. Accordingly, there is an expectation of greater variation around the time of the origin of a clade than later in its evolutionary history. This 'canalisation' has been tested in terms of morphological disparity (interspecific variation), whereas intraspecific variation in macroevolution is rarely studied. We analysed extensive data of brachial counts in crinoid populations from the Ordovician to the Recent to test for canalisation in morphological intraspecific variation. Our results show no support for the canalisation hypothesis through the Phanerozoic. This lack of pattern is maintained even when considering crinoid subclades separately. Our study is an example of the lack of universality in such macroevolutionary patterns both in terms of organisms and in terms of modules within them. It is also an example on the challenges and limitations of palaeontological studies of macroevolutionary processes.

Refined Lab-score, a Risk Score Predicting Serious Bacterial Infection in Febrile Children Less Than 3 Years of Age.

BACKGROUND: The identification of serious bacterial infection (SBI) in children with fever without source remains a challenge. A risk score called Lab-score, based on C-reactive protein, procalcitonin and urinary dipstick results was derived to predict SBI. However, all biomarkers were initially dichotomized, leading to weak statistical reliability and lack of transportability across diverse settings. We aimed to refine and validate this risk-score algorithm. METHODS: The Lab-score was refined using a secondary analysis of a multicenter cohort study of children with fever without source via multilevel regression modeling. The external validation was conducted on data from a Canadian cohort study. RESULTS: Eight hundred seventy-seven children (24% SBI) were included for the derivation study, and 347 (16% SBI) for validation. Only C-reactive protein, procalcitonin, age and urinary dipstick remained independently associated with SBI. The model achieved an area under the receiver operating characteristic (ROC) curve of 0.94 (95% confidence interval [CI]: 0.93-0.96), which was significantly higher than any other isolated biomarker (P < 0.0001), and the original Lab-score (P < 0.0001). According to a decision curve analysis, the model yielded a better strategy than those based on independently considered biomarkers, or on the original Lab-score. The threshold analysis led to a cutoff that yielded 96% (95% CI: 92-98) sensitivity and 73% (95% CI: 70-77) specificity. The external validation found similar predictive abilities: 0.96 area under the ROC curve (95% CI: 0.93-0.99), 95% sensitivity (95% CI: 85-99) and 87% specificity (95% CI: 83-91). CONCLUSION: The refined Lab-score demonstrated higher prediction ability for SBI than the original Lab-score, with promising wider applicability across settings. These results require validation in additional populations.

Extraintestinal Manifestations of Pediatric Inflammatory Bowel Disease: Prevalence, Presentation, and Anti-TNF Treatment.

BACKGROUND: There is a paucity of data on extraintestinal manifestations (EIM) and their treatment in pediatric patients with inflammatory bowel disease (IBD). METHODS: Since 2008, the Pediatric Swiss IBD Cohort Study has collected data on the pediatric IBD population in Switzerland. Data on 329 patients were analyzed retrospectively. RESULTS: A total of 55 patients (16.7%) experienced 1-4 EIM (39 Crohn disease, 12 ulcerative colitis, and 4 IBD-unclassified patients). At IBD onset, presence of EIM was more frequent than in the adult population (8.5% vs 5.0%, P = 0.014). EIM were more frequent in Crohn disease when compared to ulcerative colitis/IBD-unclassified (22.5% vs 10.3%, P = 0.003). The most prevalent EIM were peripheral arthritis (26/329, 7.9%) and aphthous stomatitis (24/329, 7.3%). Approximately 27.6% of all EIM appeared before IBD diagnosis. Median time between IBD diagnosis and occurrence of first EIM was 1 month (-37.5-149.0). Thirty-one of the 55 patients (56.4%) were treated with 1 or more anti-tumor necrosis factor (TNF) agents. IBD patients with EIM were more likely to be treated with anti-TNF compared to those without (56.4% vs 35.0%, P = 0.003). Response rates to anti-TNF depended on underlying EIM and were best for peripheral arthritis (61.5%) and uveitis (66.7%). CONCLUSIONS: In a cohort of pediatric patients with IBD, EIM were frequently encountered. In up to 30%, EIM appeared before IBD diagnosis. Knowledge of these findings may translate into an increased awareness of underlying IBD, thereby decreasing diagnostic delay. Anti-TNF for the treatment of certain EIM is effective, although a substantial proportion of new EIM may present despite ongoing anti-TNF therapy.

Understanding form and function of the stem in early flattened echinoderms (pleurocystitids) using a microstructural approach.

Pleurocystitid rhombiferans are among the most unusual echinoderms whose mode of life has been long debated. These echinoderms are usually interpreted as vagile epibenthic echinoderms, moving over the sea bottom by means of a flexible stem. Although their life habits and posture are reasonably well understood, the mechanisms that control the movement of stem are highly controversial. Specifically, it is unknown whether the stem flexibility was under the control of muscles or ligamentary mutable collagenous tissues (MCTs). Here, we reconstruct palaeoanatomy of the two Ordovician pleurocystitid rhombiferans (Pleurocystites and Amecystis) based on stereom microstructure. We show that the articular facets of columnals in pleurocystitid rhombiferans are composed of fine labyrinthic stereom. Comparison with modern echinoderms suggests that this type of stereom was associated with muscles implying that their stem was a muscular locomotory organ supporting an active mode of life.

Palaeogeographic implications of a new iocrinid crinoid (Disparida) from the Ordovician (Darriwillian) of Morocco.

Complete, articulated crinoids from the Ordovician peri-Gondwanan margin are rare. Here, we describe a new species, Iocrinus africanus sp. nov., from the Darriwilian-age Taddrist Formation of Morocco. The anatomy of this species was studied using a combination of traditional palaeontological methods and non-destructive X-ray micro-tomography (micro-CT). This revealed critical features of the column, distal arms, and aboral cup, which were hidden in the surrounding rock and would have been inaccessible without the application of micro-CT. Iocrinus africanus sp. nov. is characterized by the presence of seven to thirteen tertibrachials, three in-line bifurcations per ray, and an anal sac that is predominantly unplated or very lightly plated. Iocrinus is a common genus in North America (Laurentia) and has also been reported from the United Kingdom (Avalonia) and Oman (middle east Gondwana). Together with Merocrinus, it represents one of the few geographically widespread crinoids during the Ordovician and serves to demonstrate that faunal exchanges between Laurentia and Gondwana occurred at this time. This study highlights the advantages of using both conventional and cutting-edge techniques (such as micro-CT) to describe the morphology of new fossil specimens.

Cambrian cinctan echinoderms shed light on feeding in the ancestral deuterostome.

Reconstructing the feeding mode of the latest common ancestor of deuterostomes is key to elucidating the early evolution of feeding in chordates and allied phyla; however, it is debated whether the ancestral deuterostome was a tentaculate feeder or a pharyngeal filter feeder. To address this, we evaluated the hydrodynamics of feeding in a group of fossil stem-group echinoderms (cinctans) using computational fluid dynamics. We simulated water flow past three-dimensional digital models of a Cambrian fossil cinctan in a range of possible life positions, adopting both passive tentacular feeding and active pharyngeal filter feeding. The results demonstrate that an orientation with the mouth facing downstream of the current was optimal for drag and lift reduction. Moreover, they show that there was almost no flow to the mouth and associated marginal groove under simulations of passive feeding, whereas considerable flow towards the animal was observed for active feeding, which would have enhanced the transport of suspended particles to the mouth. This strongly suggests that cinctans were active pharyngeal filter feeders, like modern enteropneust hemichordates and urochordates, indicating that the ancestral deuterostome employed a similar feeding strategy.

Oral region homologies in paleozoic crinoids and other plesiomorphic pentaradial echinoderms.

The phylogenetic relationships between major groups of plesiomorphic pentaradial echinoderms, the Paleozoic crinoids, blastozoans, and edrioasteroids, are poorly understood because of a lack of widely recognized homologies. Here, we present newly recognized oral region homologies, based on the Universal Elemental Homology model for skeletal plates, in a wide range of fossil taxa. The oral region of echinoderms is mainly composed of the axial, or ambulacral, skeleton, which apparently evolved more slowly than the extraxial skeleton that forms the majority of the body. Recent phylogenetic hypotheses have focused on characters of the extraxial skeleton, which may have evolved too rapidly to preserve obvious homologies across all these groups. The axial skeleton conserved homologous suites of characters shared between various edrioasteroids and specific blastozoans, and between other blastozoans and crinoids. Although individual plates can be inferred as homologous, no directly overlapping suites of characters are shared between edrioasteroids and crinoids. Six different systems of mouth (peristome) plate organization (Peristomial Border Systems) are defined. These include four different systems based on the arrangement of the interradially-positioned oral plates and their peristomial cover plates, where PBS A1 occurs only in plesiomorphic edrioasteroids, PBS A2 occurs in plesiomorphic edrioasteroids and blastozoans, and PBS A3 and PBS A4 occur in blastozoans and crinoids. The other two systems have radially-positioned uniserial oral frame plates in construction of the mouth frame. PBS B1 has both orals and uniserial oral frame plates and occurs in edrioasterid and possibly edrioblastoid edrioasteroids, whereas PBS B2 has exclusively uniserial oral frame plates and is found in isorophid edrioasteroids and imbricate and gogiid blastozoans. These different types of mouth frame construction offer potential synapomorphies to aid in parsimony-based phylogenetics for exploring branching order among stem groups on the echinoderm tree of life.

Cambrian spiral-plated echinoderms from Gondwana reveal the earliest pentaradial body plan.

Echinoderms are unique among animal phyla in having a pentaradial body plan, and their fossil record provides critical data on how this novel organization came about by revealing intermediate stages. Here, we report a spiral-plated animal from the early Cambrian of Morocco that is the most primitive pentaradial echinoderm yet discovered. It is intermediate between helicoplacoids (a bizarre group of spiral-bodied echinoderms) and crown-group pentaradiate echinoderms. By filling an important gap, this fossil reveals the common pattern that underpins the body plans of the two major echinoderm clades (pelmatozoans and eleutherozoans), showing that differential growth played an important role in their divergence. It also adds to the striking disparity of novel body plans appearing in the Cambrian explosion.

The oldest echinoderm faunas from Gondwana show that echinoderm body plan diversification was rapid.

The earliest fossil echinoderms have, until now, come almost exclusively from North America and are represented by few taxa, all of which have a radiate body plan. Here we report the discovery of two new echinoderm faunas from the early part of the Cambrian of Morocco (West Gondwana). The former represents the oldest echinoderm fauna from Gondwana, approximately equivalent in age to those from North America, and the latter the oldest diversified fauna from Gondwana. In both cases, the appearance of well-preserved echinoderms coincides with a change in palaeogeographic regime. The presence of four markedly different echinoderm body plans in these earliest faunas indicates that considerable diversification had already taken place by 510 Ma. Yet all share the same distinctive biomineralized skeleton that, based on the fossil record and ocean geochemistry, probably evolved just 10-15 my earlier. This suggests that a rapid rate of morphological divergence took place during the initial stages of echinoderm evolution.

Plated Cambrian bilaterians reveal the earliest stages of echinoderm evolution.

Echinoderms are unique in being pentaradiate, having diverged from the ancestral bilaterian body plan more radically than any other animal phylum. This transformation arises during ontogeny, as echinoderm larvae are initially bilateral, then pass through an asymmetric phase, before giving rise to the pentaradiate adult. Many fossil echinoderms are radial and a few are asymmetric, but until now none have been described that show the original bilaterian stage in echinoderm evolution. Here we report new fossils from the early middle Cambrian of southern Europe that are the first echinoderms with a fully bilaterian body plan as adults. Morphologically they are intermediate between two of the most basal classes, the Ctenocystoidea and Cincta. This provides a root for all echinoderms and confirms that the earliest members were deposit feeders not suspension feeders.

Validation of a laboratory risk index score for the identification of severe bacterial infection in children with fever without source.

OBJECTIVE: The identification of severe bacterial infection (SBI)in children with fever without source (FWS) remains a diagnostic problem. The authors previously developed in their Swiss population a risk index score, called the Lab-score, associating three independent predictors of SBI, namely C reactive protein (CRP), procalcitonin (PCT) and urinary dipstick. The objective of this study was to validate the Lab-score in a population of children with FWS different from the derivation model. METHODS: A prospective study, conducted in Padova, on 408 children aged 7 days to 36 months with FWS was recently published. PCT, CRP, white blood cell count (WBC) and urinary dipstick were determined in all children. The Lab-score was applied to this population and the diagnostic characteristics for the detection of SBI were calculated for the Lab-score and for any single variable used in the Italian study. RESULTS: For the identification of SBI, the sensitivity of a score ≥3 was 86% (95% CI 77% to 92%) and the specificity 83% (95% CI 79% to 87%). The area under the receiver operating characteristic curve for the Lab-score (0.91) was significantly superior to that of any single variable: 0.71 for WBC, 0.86 for CRP and 0.84 for PCT. The Lab-score performed better than other laboratory markers, even when applied to children of different age groups (<3 months, 3-12 months and >12 months). The results obtained in this validation set population were comparable with those of the derivation set population. CONCLUSIONS: This study validated the Lab-score as a valuable tool to identify SBI in children with FWS.

A score identifying serious bacterial infections in children with fever without source.

The objective of the study was to develop a simple clinical tool to identify serious bacterial infection (SBI) in children with fever without a source. For each child, a clinical assessment, a white blood cell count, a urine analysis, a determination of C-reactive protein, procalcitonin, and appropriate cultures were performed. Two hundred two children were studied of whom 54 (27%) had SBI. In the multivariate analysis, only procalcitonin [odds ratio (OR): 37.6], C-reactive protein (OR: 7.8), and urine dipstick (OR: 23.2) remained significantly associated with SBI. The sensitivity of the score for the identification of SBI was 94% and the specificity 81%. In the validation set the sensitivity of the score was 94% and the specificity 78%.

Correlation between specific immunoglobulin E levels and the severity of reactions in egg allergic patients.

Different studies proposed specific immunoglobulin E (IgE) cut-off levels for the diagnosis of egg allergy. Little is known if IgE titres could be helpful for prediction of the severity of the reaction. The aim of this study was to determine whether IgE titres are associated with the severity of the reaction during a standardized egg challenge. We reviewed data obtained during oral challenge tests to egg performed between 2003 and 2005, and attributed a clinical score to the positive reactions. Serum specific IgE levels were analysed in relation with the severity of the reaction. We analysed data from 51 oral food challenges to egg, raw or cooked. Sixteen challenges (31%) were negative and 35 (69%) were positive of which 13 challenges (37% of positive reactions) elicited a severe reaction. IgE levels in our patients ranged from undetectable to 14.90 kU/l. We could determine a cut-off level of 8.20 kU/l for a 90% probability of clinical reactivity. IgE titres were statistically significantly different between the patients with absent, mild and moderate or severe reaction. Patients with negative challenge had IgE levels between 0.35 and 6.41 kU/l (median 1.17), those with mild and moderate reaction had IgE levels ranging from 0.35 to 14.90 (median 2.47) and patients with severe reactions had IgE between 1.18 and 11.00 (median 3.70) (p = 0.006). Our results show a correlation between IgE titres and the severity of the clinical reaction to egg. IgE titres may help to determine the potential risk of a reaction to eggs.

Continuing food-avoidance diets after negative food challenges.

Negative food challenges for follow-up in patients previously diagnosed with food allergy should logically be followed by a normal diet. However, all patients do not reintroduce the food. The aims of the study were to define the proportion of negative food challenge not followed by a normal diet, and to identify possible reasons for not reintroducing the food. Patients with a negative food challenge were sent a questionnaire by mail. Items in the questionnaire included the symptoms at diagnosis, the duration of the diet, the fear of an accidental reaction during the avoidance diet and how it influenced the social life. Patients were also asked if the food was reintroduced after the negative food challenge, and if not, for which reasons. In 25.4% of the questionnaires (18/71) respondents reported that the food was not reintroduced. Patients with a previous diagnosis of peanut allergy tended to reintroduce the food less frequently than patients allergic to other foods. Girls were found to significantly less frequently reintroduce the food than boys. However, neither the severity of the initial reaction, the anxiety of an accidental reaction during the avoidance diet, nor a prolonged avoidance diet did influence the decision to reintroduce the food. Among other reasons listed, fears of persistence of allergies, with recurrent pruritus or non-specific skin rashes after eating the food, were reported in 12.7% of the total number of questionnaires. Patients who reintroduced the food reported that their social life generally improved. One quarter of previously allergic patients continue a food avoidance diet despite a negative challenge. We suggest reassessing food consumption in all patients after a negative food challenge, and in those still avoiding the specific food to consider a repeated challenge test.