Evolutionary diversification of the canonical Wnt signaling effector TCF/LEF in chordates

This work was supported by the Biotechnology and Biological Sciences Research Council (BBSRC), linked projects, references BB/S016856/1 and BB/S020640/1.Wnt signaling is essential during animal development and regeneration, but also plays an important role in diseases such as cancer and diabetes. The canonical Wnt signaling pathway is one of the most conserved signaling cascades in the animal kingdom, with the T-cell factor/lymphoid enhancer factor (TCF/LEF) proteins the major mediators of Wnt/β-catenin-regulated gene expression. In comparison to invertebrates, vertebrates possess a high diversity of TCF/LEF family genes, implicating this as a possible key change to Wnt signaling at the evolutionary origin of vertebrates. However, the precise nature of this diversification is only poorly understood. The aim of this study is to clarify orthology, paralogy and isoform relationships within the TCF/LEF gene family within chordates via in silico comparative study of TCF/LEF gene structure, molecular phylogeny and gene synteny. Our results support the notion that the four TCF/LEF paralog subfamilies in jawed vertebrates (gnathostomes) evolved via the two rounds of whole-genome duplication that occurred during early vertebrate evolution. Importantly, gene structure comparisons and synteny analysis of jawless vertebrate (cyclostome) TCFs suggest that a TCF7L2-like form of gene structure is a close proxy for the ancestral vertebrate structure. In conclusion, we propose a detailed evolutionary path based on a new pre-whole-genome duplication vertebrate TCF gene model. This ancestor gene model highlights the chordate and vertebrate innovations of TCF/LEF gene structure, providing the foundation for understanding the role of Wnt/β-catenin signaling in vertebrate evolution.Publisher PDFPeer reviewe

Yamanaka Factors in the Budding Tunicate Botryllus schlosseri Show a Shared Spatio-Temporal Expression Pattern in Chordates

In vertebrates, the four transcription factors Sox2, c-Myc, Pou5f1 and Klf4 are involved in the differentiation of several tissues during vertebrate embryogenesis; moreover, they are normally co-expressed in embryonic stem cells and play roles in pluripotency, self-renewal, and maintenance of the undifferentiated state in adult cells. The in vitro forced co-expression of these factors, named Yamanaka factors (YFs), induces pluripotency in human or mouse fibroblasts. Botryllus schlosseri is a colonial tunicate undergoing continuous stem cell-mediated asexual development, providing a valuable model system for the study of pluripotency in the closest living relatives of vertebrates. In this study, we identified B. schlosseri orthologs of human Sox2 and c-Myc genes, as well as the closest homologs of the vertebrate-specific Pou5f1 gene, through an in-depth evolutionary analysis of the YF gene families in tunicates and other deuterostomes. Then, we studied the expression of these genes during the asexual cycle of B. schlosseri using in situ hybridization in order to investigate their possible involvement in tissue differentiation and in pluripotency maintenance. Our results show a shared spatio-temporal expression pattern consistent with the reported functions of these genes in invertebrate and vertebrate embryogenesis. Moreover, Myc, SoxB1 and Pou3 were expressed in candidate stem cells residing in their niches, while Pou2 was found expressed exclusively in the immature previtellogenic oocytes, both in gonads and circulating in the colonial vascular system. Our data suggest that Myc, SoxB1 and Pou3 may be individually involved in the differentiation of the same territories seen in other chordates, and that, together, they may play a role in stemness even in this colonial ascidian

Hitch-hikers of the sea: concurrent morphological and molecular identification of Symplegma brakenhielmi (Tunicata: Ascidiacea) in the western Mediterranean Sea

We report here one of the first records of the non-indigenous colonial ascidian Symplegma brakenhielmi (Michaelsen, 1904) in the western Mediterranean Sea. Colonies of this invasive species have been collected in 2014 and 2018 along North-eastern Sardinia coasts (Olbia, Italy). Further colonies have been observed in 2016 in the Mar Piccolo basin (Gulf of Taranto, Italy). Both areas are strongly influenced by anthropogenic activities such as commercial shipping and aquaculture, suggesting these human-mediated pathways the most likely vectors of introduction. In both areas, the colonies present two different color phenotypes, the yellow and the red type, with the yellow coloration never found before in the Mediterranean Sea. Morphological and DNA barcode analyses of the collected specimens show that both these color types belong to the same species. Phylogenetic and species delimitation analyses based on the DNA barcode confirm our identification as S. brakenhielmi, but also indicate a surprisingly high similarity with published sequences of other two species, including the co-generic species Symplegma rubra Monniot, 1972. Morphological and molecular examination of a large number of samples of these species would be need in the near future to clarify this issue

Spatial Olfactory Memory and Spatial Olfactory Navigation, Assessed with a Variant of Corsi Test, Is Modulated by Gender and Sporty Activity

Many studies have focused on navigation, spatial skills, and the olfactory system in comparative models, including those concerning the relationship between them and physical activity. Although the results are often in contrast with each other, it is assumed that physical activity can affect cognition in different ways-both indirectly and through a certain influence on some brain structures. In contrast, there is little research that focuses on the relationship between spatial abilities and olfactory abilities in humans. This research aimed to evaluate and compare the performance in working memory tasks of athletes and non-athletes who require good visual-spatial navigation, olfactory-spatial navigation, and olfactory-semantic skills. The study involved 236 participants (83 athletes) between the ages of 18 and 40. All subjects were matched by age or sex. The standard Corsi Block Tapping Test (CBTT) was administrated to investigate the visual-spatial memory. Olfactory-spatial navigation and olfactory-semantic skills were assessed with two modified versions of CBTT: Olfactory CBTT (OCBTT) and Semantic-Olfactory CBTT (SOCBTT) respectively. The results show differences between the CORSI conditions in direction of a poor performance for athletes. A gender effect in favor of men was also found, particularly in the classic version of the CBTT. Both groups performed better in the classic version of the CBTT than OCBTT and SOCBTT. The mean of SOCBTT results is markedly lower, perhaps due to the different information processing systems needed to perform this kind of task. It is possible to explain how sports practice can affect tasks that require spatial skills and olfactory perception differently, thus supporting new hypotheses and opening new scientific horizons

An elongated COI fragment to discriminate botryllid species and as an improved ascidian DNA barcode

Botryllids are colonial ascidians widely studied for their potential invasiveness and as model organisms, however the morphological description and discrimination of these species is very problematic, leading to frequent specimen misidentifications. To facilitate species discrimination and detection of cryptic/new species, we developed new barcoding primers for the amplification of a COI fragment of about 860 bp (860-COI), which is an extension of the common Folmer's barcode region. Our 860-COI was successfully amplified in 177 worldwide-sampled botryllid colonies. Combined with morphological analyses, 860-COI allowed not only discriminating known species, but also identifying undescribed and cryptic species, resurrecting old species currently in synonymy, and proposing the assignment of clade D of the model organism Botryllus schlosseri to Botryllus renierii. Importantly, within clade A of B. schlosseri, 860-COI recognized at least two candidate species against only one recognized by the Folmer's fragment, underlining the need of further genetic investigations on this clade. This result also suggests that the 860-COI could have a greater ability to diagnose cryptic/new species than the Folmer's fragment at very short evolutionary distances, such as those observed within clade A. Finally, our new primers simplify the amplification of 860-COI even in non-botryllid ascidians, suggesting their wider usefulness in ascidians

Finding aquaporins in annelids : An evolutionary analysis and a case study

Funding Information: This research was funded by PRIN2017 Programmi di Ricerca Scientifica di Rilevante Interesse Nazionale 2017 (grant # 2017J92TM5) by Italian MUR to G.C. and by the Molecular Bio-diversity Laboratory of the Italian node of Lifewatch (CNR, Consiglio Nazionale delle Ricerche) to C.G.Peer reviewedPublisher PD

LC-HRMS-Database Screening Metrics for Rapid Prioritization of Samples to Accelerate the Discovery of Structurally New Natural Products

In order to accelerate the isolation and characterization of structurally new or novel secondary metabolites, it is crucial to develop efficient strategies that prioritize samples with greatest promise early in the workflow so that resources can be utilized in a more efficient and cost-effective manner. We have developed a metrics-based prioritization approach using exact LC-HRMS, which uses data for 24 618 marine natural products held in the PharmaSea database. Each sample was evaluated and allocated a metric score by a software algorithm based on the ratio of new masses over the total (sample novelty), ratio of known masses over the total (chemical novelty), number of peaks above a defined peak area threshold (sample complexity), and peak area (sample diversity). Samples were then ranked and prioritized based on these metric scores. To validate the approach, eight marine sponges and six tunicate samples collected from the Fiji Islands were analyzed, metric scores calculated, and samples targeted for isolation and characterization of new compounds. Structures of new compounds were elucidated by spectroscopic techniques, including 1D and 2D NMR, MS, and MS/MS. Structures were confirmed by computer-assisted structure elucidation methods (CASE) using the ACD/Structure Elucidator Suite

Olfactory and Visuo-Spatial short term working memory: localization of an olfactory marker in a modified Corsi Block Tapping Test

One of the main relevant Tests that analyzes the visuo-spatial component can be considered the Courses Block Tapping Test (CBTT). The visuo-spatial component is an extremely present component also in the olfactory perception, where, from the evolutionary point of view, it seems to be the further development of ancestral olfactory abilities linked to the location of the olfactory marker. In the present research, through the use of the CBTT associated with an olfactory component, it was investigated how the sense of smell can be related to tasks requiring the use of visuo-spatial memory and whether this component can be gender-dependent. In the present study, 153 healthy subjects were recruited (mean age 22.6 ± 4.3; 92 women). The Courses Test was administered according to three different sessions and modalities: 1) classical version of the CBTT; 2) Olfactory CBTT (OCBTT); 3) Semantic-Olfactory CBTT (SOCBTT). In the OCBTT, squares of paper wet with specific odorants were placed on the cubes. The layout of the block (B), the same for all subjects, was: Eucalyptus (B1); Carvone (B2); Eugenol(B3); Isoamyl Acetate (B4); Geranium (B5); Phenylethyl alcohol (B6); Hexanal (B7); Acetophenone (B8), Cinnamon (B9). During the experimentation phase the squares arranged above the cubes were smelled according to sequences and methods described for the standard CBTT. At the end of each sequence, a paper square, wet with an odorant pseudo-randomly chosen, was extracted from a pocket and administrated to the subject. Therefore, the experimenter asked to indicate on which B the odorous square corresponded to the one just presented. In this condition, the same exclusion parameters of the CBTT were used. At the beginning of the SOCBTT, the experimenter read, only one time, the complete list of the odorants used. Then the subjects performed the same task of the OCBTT, but, at the end of each sequence, the subject had to identify through the naming the odorants recognized during the sequence. The sequence of the tests was alternated for each subject to avoid a primacy or habituation effect linked to olfactory stimulation. A GLM repeated measures was performed considering as between factor the variable Group (Male and Women) and as within factors the SPAN scores obtained in the three different CBTT modalities (i.e., CBTT; OCBTT; SOCBTT). Furthermore, a correlation analysis was carried out between the three levels of the test. The results of the analysis showed a gender difference in terms of a better performance of men for CBTT, OCBTT and SOCBTT; moreover, the SPAN score was higher in CBTT, and decreased respectively in OCBTT and SOCBTT. Correlation analysis showed a positive correlation between the three CBTT variants (i.e, CBTT, OCBTT and SOCBTT). These results confirm that there is a common perceptual pathway between olfactory and visuo-spatial working memory, also evident in behavioural data. Future work will focus on validation of these test variants