Evolutionary and Genomic Diversity of True Polyploidy in Tetrapods

: True polyploid organisms have more than two chromosome sets in their somatic and germline cells. Polyploidy is a major evolutionary force and has played a significant role in the early genomic evolution of plants, different invertebrate taxa, chordates, and teleosts. However, the contribution of polyploidy to the generation of new genomic, ecological, and species diversity in tetrapods has traditionally been underestimated. Indeed, polyploidy represents an important pathway of genomic evolution, occurring in most higher-taxa tetrapods and displaying a variety of different forms, genomic configurations, and biological implications. Herein, we report and discuss the available information on the different origins and evolutionary and ecological significance of true polyploidy in tetrapods. Among the main tetrapod lineages, modern amphibians have an unparalleled diversity of polyploids and, until recently, they were considered to be the only vertebrates with closely related diploid and polyploid bisexual species or populations. In reptiles, polyploidy was thought to be restricted to squamates and associated with parthenogenesis. In birds and mammals, true polyploidy has generally been considered absent (non-tolerated). These views are being changed due to an accumulation of new data, and the impact as well as the different evolutionary and ecological implications of polyploidy in tetrapods, deserve a broader evaluation

First Insights on the Karyotype Diversification of the Endemic Malagasy Leaf-Toed Geckos (Squamata: Gekkonidae: Uroplatus)

We provide here the first karyotype description of eight Uroplatus species and a characterization of their chromosomal diversity. We performed a molecular taxonomic assessment of several Uroplatus samples using the mitochondrial 12S marker and a comparative cytogenetic analysis with standard karyotyping, silver staining (Ag-NOR) and sequential C-banding + Giemsa, +Chromomycin A3 (CMA3), +4',6-diamidino-2-phenylindole (DAPI). We found chromosomal variability in terms of chromosome number (2n = 34-38), heterochromatin composition and number and localization of loci or Nucleolar Organizer Regions (NORs) (alternatively on the 2nd, 6th, 10th or 16th pair). Chromosome morphology is almost constant, with karyotypes composed of acrocentric chromosomes, gradually decreasing in length. C-banding evidenced a general low content of heterochromatin, mostly localized on pericentromeric and telomeric regions. Centromeric bands varied among the species studied, resulting in CMA3 positive and DAPI negative or positive to both fluorochromes. We also provide evidence of a first putative heteromorphic sex chromosome system in the genus. In fact, in U. alluaudi the 10th pair was highly heteromorphic, with a metacentric, largely heterochromatic W chromosome, which was much bigger than the Z. We propose an evolutionary scenario of chromosome reduction from 2n = 38 to 2n = 34, by means of translocations of microchromosomes on larger chromosomes (often involving the NOR-bearing microchromosomes). Adding our data to those available from the literature, we show that similar processes characterized the evolutionary radiation of a larger gecko clade. Finally, we hypothesize that sex chromosome diversification occurred independently in different genera

Chromosome Diversity and Evolution of the Endemic Malagasy Velvet Geckos of the Genus Blaesodactylus (Reptilia, Gekkonidae)

: We performed a molecular and phylogenetic analysis and a comparative cytogenetic study with standard karyotyping, silver staining (Ag-NOR) and sequential C-banding + Giemsa, + fluorochromes on several Blaesodactylus samples. The phylogenetic inference retrieved two main clades, the first comprises B. victori, B. microtuberculatus and B. boivini, while the second includes B. sakalava, B. antongilensis and B. ambonihazo. The available samples of B. sakalava form two different clades (here named B. sakalava clade A and clade B), which probably deserve a taxonomic re-evaluation. We found a karyological variability in Blaesodactylus in terms of chromosome number (2n = 40-42), morphology, location of NORs, and heterochromatin distribution pattern. Blaesodactylus antongilensis and B. sakalava clade A and B showed a karyotype of 2n = 40 mostly telocentric chromosomes. Pairs 1 and 6 were metacentric in B. sakalava clade A and B, while pair 1 was composed of subtelocentric/submetacentric elements in B. antongilensis. In contrast, B. boivini displayed a karyotype with 2n = 42 only telocentric chromosomes. NORs were on the first chromosome pair in B. boivini, and on the second pair in B. antongilensis. Adding our data to those available from the literature on evolutionarily related species, we highlight that the chromosome diversification in the genus probably proceeded towards a progressive reduction in the chromosome number and the formation of metacentric elements

Aspirin-dependent effects on purinergic P2Y1 receptor express

Chronic treatment with aspirin in healthy volunteers (HVs) is associated with recovery of adenosine diphosphate (ADP)-induced platelet activation. The purinergic P2Y1 receptor exerts its effects via a Gq-protein, which is the same biochemical pathway activated by thromboxane-A2 receptor. We hypothesized that recovery of ADP-induced platelet activation could be attributed to increased P2Y1 expression induced by chronic aspirin exposure. We performed a multi-phase investigation which embraced both in vitro and in vivo experiments conducted in (1) human megakaryoblastic DAMI cells, (2) human megakaryocytic progenitor cell cultures, (3) platelets obtained from HVs treated with aspirin and (4) platelets obtained from aspirin-treated patients. DAMI cells treated with aspirin or WY14643 (PPARα agonist) had a significant up-regulation of P2Y1 mRNA, which was shown to be a PPARα-dependent process. In human megakaryocytic progenitors, in the presence of aspirin or WY14643, P2Y1 mRNA expression was higher than in mock culture. P2Y1 expression increased in platelets obtained from HVs treated with aspirin for 8 weeks. Platelets obtained from patients who were on aspirin for more than 2 months had increased P2Y1 expression and ADP-induced aggregation compared with patients on aspirin treatment for less than a month. Overall, our results suggest that aspirin induces genomic changes in megakaryocytes leading to P2Y1 up-regulation and that PPARα is the nuclear receptor involved in this regulation. Since P2Y1 is coupled to the same Gq-protein of thromboxane-A2 receptor, platelet adaptation in response to pharmacological inhibition seems not to be receptor specific, but may involve other receptors with the same biochemical pathway

Longevidade comparada e idade da maturidade sexual em doze anuros dos gêneros Boophis, Gephyromantis e Mantidactylus (Anura: Mantellidae) da floresta tropical de Madagascar

Apresentamos aqui dados sobre a idade na maturidade sexual e longevidade para algumas espécies de Mantellidae dos gêneros Boophis, Gephyromantis e Mantidactylus que habitam a floresta tropical de baixa altitude de Masoala (nordeste de Madagascar). Contagens de linhas de crescimento (LAGs) foram utilizadas para calcular a longevidade dessas espécies; esses dados contribuem para avaliações do nível de ameaça desses anuros. Boophis inclui espécies de médio a grande porte (SVL = 30–65 mm) que atingem a maturidade sexual em 1–3 anos e vivem de 3–9 anos (i.e., longevidade média). Mantidactylus e Gephyromatis incluem espécies de pequeno a grande porte (SVL = 22–107 e 35–49 mm, respectivamente) que atingem maturidade sexual em 1–3 anos e vivem de 1–8 e 3–7 anos, respectivamenteData on the age at sexual maturity and longevity of some mantellid species of the genera Boophis, Gephyromantis, and Mantidactylus that inhabit the low altitude rainforest of Masoala (northeastern Madagascar) are presented. Counts of lines of arrested growth (LAGs) were used to calculate longevity in these species; these data contribute to assessment of the threat level of the studied anurans. Boophis includes species of mediumto large-sized frogs (SVL = 30–65 mm) that attain sexual maturity in 1–3 years and live 3–9 years (i.e., mid-longevity). Mantidactylus and Gephyromatis include small- to largesized species (SVL = 22–107 mm and 35–49 mm, respectively) that attain sexually maturity in 1–3 years and live 1–8 and 3–7 years, respectivel

Chromosome analysis on Central and Southern Italy population of the common toad, Bufo bufo (Amphibia, Anura)

Amphibians constitute a very good model to explore the historical aspects of species distributions due to their low dispersal capacity and low individual vagility. Bufonidae are one of the most speciose family of Anura, including taxa, such as Bufo bufo, widespread in Eurasian regions. We performed a karyological study with standard and sequential C-banding + fluorochromes (Chromomycin A3 (CMA) and Diamidinophenylindole (DAPI) on several tadpoles from different populations of Central and Southern Italy. All the examined tadpoles exhibited the standard Bufokaryotype of 2n = 22 biarmed chromosomes, with the first six pairs larger than the other five (7 - 11) pairs and NOR associated heterochromatin distal on the long arms of the 6thchromosome pair, that was also the only chromosome CMA-positive region. C-banding evidenced centromeric heterochromatin, DAPI positive, on all the chromosomes in all the studied populations from Central Italy. The Southern Italy populations differed in additional paracentromeric C-bands on the short arms of chromosomes 1, 3 and 5. These results support the partition of Central populations of B. bufo from the Southern ones, as evidenced also from molecular phylogenetic studie

Characterization of Two Transposable Elements and an Ultra-Conserved Element Isolated in the Genome of Zootoca vivipara (Squamata, Lacertidae)

: Transposable elements (TEs) constitute a considerable fraction of eukaryote genomes representing a major source of genetic variability. We describe two DNA sequences isolated in the lizard Zootoca vivipara, here named Zv516 and Zv817. Both sequences are single-copy nuclear sequences, including a truncation of two transposable elements (TEs), SINE Squam1 in Zv516 and a Tc1/Mariner-like DNA transposon in Zv817. FISH analyses with Zv516 showed the occurrence of interspersed signals of the SINE Squam1 sequence on all chromosomes of Z. vivipara and quantitative dot blot indicated that this TE is present with about 4700 copies in the Z. vivipara genome. FISH and dot blot with Zv817 did not produce clear hybridization signals. Bioinformatic analysis showed the presence of active SINE Squam 1 copies in the genome of different lacertids, in different mRNAs, and intronic and coding regions of various genes. The Tc1/Mariner-like DNA transposon occurs in all reptiles, excluding Sphenodon and Archosauria. Zv817 includes a trait of 284 bp, representing an amniote ultra-conserved element (UCE). Using amniote UCE homologous sequences from available whole genome sequences of major amniote taxonomic groups, we performed a phylogenetic analysis which retrieved Prototheria as the sister group of Metatheria and Eutheria. Within diapsids, Testudines are the sister group to Aves + Crocodylia (Archosauria), and Sphenodon is the sister group to Squamata. Furthermore, large trait regions flanking the UCE are conserved at family level

Haplotype characterization of a stranded common minke whale calf (Balaenoptera acutorostrata lacépède, 1804): Is the mediterranean sea a potential calving or nursery ground for the species?

The stranding of a suckling calf of Common Minke Whale (Balaenoptera acutorostrata) on the coast near Salerno (Campania, Southern Italy) is reported. The molecular analysis of a partial sequence of the mitochondrial DNA control region shows that the animal bore a haplotype identical to haplotype Ba169 considered as typical of individuals from North Atlantic population. Historical data and our results suggest the possibility that the Mediterranean Sea might be a potential calving or nursery ground for this species

Helix straminea Briganti, 1825 in Italy (Gastropoda: Pulmonata): taxonomic history, morphology, biology, distribution and phylogeny

The land snail taxon Helix straminea Briganti, 1825 has been reintroduced as a valid species in 2014. We provide here a comprehensive account of its taxonomy, distribution, anatomy, phylogeny and karyology in Italy. An overview of the historical views on the validity of the species is presented and faunistic data are reviewed and implemented with new records from Campania and Basilicata. A lectotype is fixed for H. straminea from the syntypes stored in the Muséum d'Histoire Naturelle of Genève, as well as for three other taxa (Helix straminiformis Bourguignat, 1876, Helix yleobia Bourguignat, 1883 and Helix straminea ssp. elongata Bourguignat, 1860). Genital system, radula and karyotype are described for the first time. Molecular analysis of two mitochondrial genes combining GenBank data and the new sequences presented in this paper showed no differentiation between the northern and southern Italian populations. The conservation status of the species and its possible threats are discussed

Dabigatran-induced acute liver injury in older patients: case report and literature review

Objective. Dabigatran, a direct inhibitor of thrombin, represents an effective alternative to warfarin. Despite the good tolerance and predictable pharmacokinetic profile, dabigatran may be associated to adverse reactions, including gastrointestinal disorders. Here we report on a case of hepatotoxicity along with an extensive revision of the available literature on dabigatran induced liver injury Methods & results. An 84 years old man attended the Emergency Department after experiencing fatigue for a few days. He suffered from atrial fibrillation and had been initiated on dabigatran (110 mg bid) in the last four weeks. Clinical examination revealed tachycardia, scleral icterus in the absence of signs of chronic hepatic disease. Blood chemistry showed altered liver function tests: AST 809 IU/L, ALT 1629 IU/L, total bilirubin 2.42 mg/dL, gGT 381 IU/L, ALP 388 IU/L, LDH 552 IU/L. Screening laboratory investigations for infectious, autoimmune or metabolic hepatotoxic pathology were unremarkable. The abdominal ultrasound examination excluded vascular causes, revealing non-homogeneous echo-structure consistent with mild hepatic steatosis. At admission to our Geriatric ward dabigatran was discontinued and fondaparinux was introduced. Resolution of the hepatitis and normalization of blood chemistry was observed within two weeks. Few cases are described regarding hepatotoxicity likely caused by the recent onset of treatment with dabigatran. Conclusions. DOACs associated hepatotoxicity is rare but potentially harmful and should be kept in mind, especially in comorbid patients with unexplained liver injury. The mechanism of liver injury during dabigatran therapy is unknown and, not related to cytochrome P450 enzymes since the drug does not affect CYP450 activity