Nervous system characterization during the development of a basal echinoderm, the feather star Antedon mediterranea

Neural development of echinoderms has always been difficult to interpret, as larval neurons degenerate at metamorphosis and a tripartite nervous system differentiates in the adult. Despite their key phylogenetic position as basal echinoderms, crinoids have been scarcely studied in developmental research. However, since they are the only extant echinoderms retaining the ancestral body plan of the group, crinoids are extremely valuable models to clarify neural evolution in deuterostomes. Antedon mediterranea is a feather star, endemic to the Mediterranean Sea. Its development includes a swimming lecithotrophic larva, the doliolaria, with basiepithelial nerve plexus, and a sessile filter-feeding juvenile, the pentacrinoid, whose nervous system has never been described in detail. Thus, we characterized the nervous system of both these developmental stages by means of immunohistochemistry and, for the first time, in situ hybridization techniques. The results confirmed previous descriptions of doliolaria morphology and revealed that the larval apical organ contains two bilateral clusters of serotonergic cells while GABAergic neurons are localized under the adhesive pit. This suggested that different larval activities (e.g., attachment and metamorphosis) are under the control of different neural populations. In pentacrinoids, the analysis showed the presence of a cholinergic entoneural system while the ectoneural plexus appeared more composite, displaying different neural populations. The expression of three neural-related microRNAs was described for the first time, suggesting that these are evolutionarily conserved also in basal echinoderms. Overall, our results set the stage for future investigations that will reveal new information on echinoderm evo-devo neurobiology

Structural and functional diversity of ferredoxin-NADP+ reductases

Although all ferredoxin-NADP+ reductases (FNRs) catalyze the same reaction, i.e. the transfer of reducing equivalents between NADP(H) and ferredoxin, they belong to two unrelated families of proteins: the plant-type and the glutathione reductase-type of FNRs. Aim of this review is to provide a general classification scheme for these enzymes, to be used as a framework for the comparison of their properties. Furthermore, we report on some recent findings, which significantly increased the understanding of the structure–function relationships of FNRs, i.e. the ability of adrenodoxin reductase and its homologs to catalyze the oxidation of NADP+ to its 4-oxo derivative, and the properties of plant-type FNRs from non-photosynthetic organisms. Plant-type FNRs from bacteria and Apicomplexan parasites provide examples of novel ways of FAD- and NADP(H)-binding. The recent characterization of an FNR from Plasmodium falciparum brings these enzymes into the field of drug design

Design of Allosteric Stimulators of the Hsp90 ATPase as New Anticancer Leads

Allosteric compounds that stimulate Hsp90 adenosine triphosphatase (ATPase) activity were rationally designed, showing anticancer potencies in the low micromolar to nanomolar range. In parallel, the mode of action of these compounds was clarified and a quantitative model that links the dynamic ligand-protein cross-talk to observed cellular and in vitro activities was developed. The results support the potential of using dynamics-based approaches to develop original mechanism-based cancer therapeutics

Impact of lower limb movement on the hemodynamics of femoropopliteal arteries: A computational study

Femoropopliteal arteries (FPAs) are subjected to a wide range of deformations, mainly determined by leg movement. FPAs are often affected by atherosclerotic plaque development, presumably influenced by the biomechanics of surrounding tissues. Although abnormal hemodynamics in FPAs appears to be an important factor in driving plaque development, to date it has been investigated in few studies, in which the leg was modeled in either fixed straight or bent configuration. Hence, the current work investigates the impact of leg movement on FPA hemodynamics. An idealized model of FPA was created to perform moving-boundary computational fluid dynamics analyses. By mimicking hip rotation, knee flexion and complete movement of walking, the hemodynamics was compared between moving- and fixed-boundary models. Moreover, additional features affecting the hemodynamics (e.g. flow-rate curve amplitude, walking speed) were examined. Significant hemodynamic differences were found between the moving- and fixed-boundary models, with the leg movement inducing higher time-averaged wall shear stress (TAWSS) (up to 66%). The flow-rate amplitude and walking period were the most influential parameters (differences in TAWSS up to 68% and 74%, respectively). In conclusion, this numerical approach highlighted the importance of considering leg movement to investigate FPA hemodynamics, and it could be employed in future patient-specific analyses

Pathophysiology of hypoxemia in mechanically-ventilated patients with COVID-19: A computed tomography study

The pathogenesis of hypoxemia during acute respiratory distress syndrome caused by SARS-CoV-2 infection (C-ARDS) is debated. Some observations led to hypothesize ventilation to perfusion mismatch, rather than anatomical shunt, as the main determinant of hypoxemia. In this observational study 24 C-ARDS patients were studied 1 (0–1) days after intubation. Patients underwent a CT scan analysis to estimate anatomical shunt and a clinical test to measure venous admixture at two fractions of inspired oxygen (FiO2), to eliminate oxygen-responsive mechanisms of hypoxemia (ventilation to perfusion mismatch and diffusion limitation). In 10 out of 24 patients venous admixture was higher than anatomical shunt both at clinical (≈50 %) and 100 % FiO2. These patients were ventilated with a higher PEEP and had lower amount of anatomical shunt compared with patients with venous admixture equal/lower than anatomical shunt. In a subset of C-ARDS patients early after endotracheal intubation, hypoxemia might be explained by an abnormally high perfusion of a relatively low anatomical shunt

Activity of a trinuclear platinum complex in human ovarian cancer cell lines sensitive and resistant to cisplatin: cytotoxicity and induction and gene-specific repair of DNA lesions

A collateral sensitivity or a very modest cross-resistance to BBR 3464 was found in 2 ovarian cancer cell lines with experimentally induced resistance to cisplatin. Loss of mismatch repair proteins (hMLH1, hPMS2) or overexpression of nucleotide excision repair proteins (ERCC1) was not detrimental for the cellular sensitivity to BBR 3464. Moreover, interesting differences in the kinetics of formation and removal of DNA lesions at the single-gene (N- ras) level were observed between BBR 3464 and CDDP. © 2001 Cancer Research Campaign www.bjcancer.co

Hmx gene conservation identifies the evolutionary origin of vertebrate cranial ganglia

The evolutionary origin of vertebrates included innovations in sensory processing associated with the acquisition of a predatory lifestyle. Vertebrates perceive external stimuli through sensory systems serviced by cranial sensory ganglia (CSG) which develop from cranial placodes; however understanding the evolutionary origin of placodes and CSGs is hampered by the gulf between living lineages and difficulty in assigning homology between cell types and structures. Here we use the Hmx gene family to address this question. We show Hmx is a constitutive component of vertebrate CSG development and that Hmx in the tunicate Ciona is able to drive the differentiation program of Bipolar Tail Neurons (BTNs), cells previously thought neural crest homologs. Using Ciona and lamprey transgenesis we demonstrate that a unique, tandemly duplicated enhancer pair regulated Hmx in the stem-vertebrate lineage. Strikingly, we also show robust vertebrate Hmx enhancer function in Ciona, demonstrating that deep conservation of the upstream regulatory network spans the evolutionary origin of vertebrates. These experiments demonstrate regulatory and functional conservation between Ciona and vertebrate Hmx, and confirm BTNs as CSG homologs. Our analysis also identifies derived evolutionary changes, including a genetic basis for secondary simplicity in Ciona and unique regulatory complexity in vertebrates

Hmx gene conservation identifies the evolutionary origin of vertebrate cranial ganglia

The evolutionary origin of vertebrates included innovations in sensory processing associated with the acquisition of a predatory lifestyle. Vertebrates perceive external stimuli through sensory systems serviced by cranial sensory ganglia (CSG) which develop from cranial placodes; however understanding the evolutionary origin of placodes and CSGs is hampered by the gulf between living lineages and difficulty in assigning homology between cell types and structures. Here we use the Hmx gene family to address this question. We show Hmx is a constitutive component of vertebrate CSG development and that Hmx in the tunicate Ciona is able to drive the differentiation program of Bipolar Tail Neurons (BTNs), cells previously thought neural crest homologs. Using Ciona and lamprey transgenesis we demonstrate that a unique, tandemly duplicated enhancer pair regulated Hmx in the stem-vertebrate lineage. Strikingly, we also show robust vertebrate Hmx enhancer function in Ciona, demonstrating that deep conservation of the upstream regulatory network spans the evolutionary origin of vertebrates. These experiments demonstrate regulatory and functional conservation between Ciona and vertebrate Hmx, and confirm BTNs as CSG homologs. Our analysis also identifies derived evolutionary changes, including a genetic basis for secondary simplicity in Ciona and unique regulatory complexity in vertebrates

Luminescent conjugates between dinuclear rhenium complexes and 17α-ethynylestradiol: synthesis, photophysical characterization, and cell imaging

Three new luminescent conjugates between dinuclear rhenium complexes and an estradiol, namely E2-Re, are described. The derivatives have the general formula [Re2(\u3bc-Cl)2(CO)6(\u3bc-R-pydz-17\u3b1-ethynylestradiol)] (R-pydz = functionalized 1,2-pyridazine), where the estradiol moiety is covalently bound to the \u3b2 position of the pyridazine ligand. Different synthetic pathways are investigated, including the inverse-type [4 + 2] Diels Alder cycloaddition reaction between the electron poor 1,2,4,5-tetrazine and 17\u3b1-ethynylestradiol for the synthesis of E2-Re1. The three E2-Re conjugates are purified on silica gel and isolated in a spectroscopically pure form in moderate to good yields (28-50%). All the E2-Re conjugates are comprehensively characterized from the spectroscopic and photophysical points of view. Cellular internalization experiments on human MCF-7 and 231 cells are also reported, displaying interesting staining differences depending on the nature of the spacer linking the estradiol unit to the organometallic fragment. Furthermore, the suitability of these conjugates to also stain simple multicellular organisms, i.e. Ciona intestinalis embryos and larvae at different stages of development, is reported here for the first time

Evaluation of extraction-free RT-qPCR methods for SARS-CoV-2 diagnostics

Extraction-based real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR) is currently the “gold standard” in SARS-CoV-2 diagnostics. However, some extraction-free RT-qPCR techniques have recently been developed. In this study, we compared the sensitivity of traditional extraction-based, heated extraction-free, and unheated extraction-free RT-qPCR methods for SARS-CoV-2 detection in nasopharyngeal swabs from symptomatic individuals. The unheated extraction-free method showed perfect agreement with the standard extraction-based RT-qPCR. By contrast, the heat-treated technique was associated with an 8.2% false negativity rate. Unheated extraction-free RT-qPCR for the molecular diagnosis of SARS-CoV-2 is a valuable alternative to the traditional extraction-based methods and may accelerate turnaround times by about two hours