Ferron H.G.,Institute Cavanilles Of Biodiversitat I Biologia Evolutiva |
Botella H.,Institute Cavanilles Of Biodiversitat I Biologia Evolutiva
PLoS ONE | Year: 2017
Thelodonts are an enigmatic group of Paleozoic jawless vertebrates that have been well studied from taxonomical, biostratigraphic and paleogeographic points of view, although our knowledge of their ecology and mode of life is still scant. Their bodies were covered by micrometric scales whose morphology, histology and the developmental process are extremely similar to those of extant sharks. Based on these similarities and on the well-recognized relationship between squamation and ecology in sharks, here we explore the ecological diversity and lifestyles of thelodonts. For this we use classic morphometrics and discriminant analysis to characterize the squamation patterns of a significant number of extant shark species whose ecology is well known. Multivariate analyses have defined a characteristic squamation pattern for each ecological group, thus establishing a comparative framework for inferring lifestyles in thelodonts. We then use this information to study the squamation of the currently described 147 species of thelodonts, known from both articulated and disarticulated remains. Discriminant analysis has allowed recognizing squamation patterns comparable to those of sharks and links them to specific ecological groups. Our results suggest a remarkable ecological diversity in thelodonts. A large number of them were probably demersal species inhabiting hard substrates, within caves and crevices in rocky environments or reefs, taking advantage of the flexibility provided by their micromeric squamations. Contrary to classical interpretations, only few thelodonts were placed among demersal species inhabiting sandy and muddy substrates. Schooling species with defensive scales against ectoparasites could be also abundant suggesting that social interactions and pressure of ectoparasites were present in vertebrates as early the Silurian. The presence of species showing scales suggestive of low to moderate speed and a lifestyle presumably associated with open water environments indicates adaptation of thelodonts to deep water habitats. Scale morphology suggests that some other thelodonts were strong-swimming pelagic species, most of them radiating during the Early Devonian in association with the Nekton Revolution. © 2017 Ferrón, Botella. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Coscolla M.,Institute Cavanilles Of Biodiversitat I Biologia Evolutiva |
Coscolla M.,CIBER ISCIII |
Coscolla M.,Swiss Tropical and Public Health Institute |
Comas I.,UK National Institute for Medical Research |
And 2 more authors.
Molecular Biology and Evolution | Year: 2011
The exchange of genetic material among bacterial strains and species is recognized as an important factor determining their evolutionary, population genetic, and epidemiological features. We present a detailed analysis of nonvertical inheritance in Legionella pneumophila, a human pathogen and facultative intracellular parasite of amoebas. We have analyzed the exchange of L. pneumophila genetic material with other bacteria at three different levels: population genetics, population genomics, and phylogenomics. At the population genetics level, we have analyzed 89 clinical and environmental isolates after sequencing six coding loci and three intergenic regions for a total of 3,923 bp. In the population genomics analysis, we have studied the roles of recombination and mutation in the common portion of the genome sequence of four L. pneumophila strains. In the phylogenomic analysis, we have studied the phylogenetic origin of 1,700 genes in the L. pneumophila pangenome. For this, we have considered 12 possible phylogenetic alternatives, derived from a reference tree obtained from 104 genes from 41 species, which have been tested under a rigorous statistical framework. The results obtained agree in assigning an important role to nonvertical inheritance in shaping the composition of the L. pneumophila genome and of the genetic variation in its populations. We have found a negative correlation between phylogenetic distance and likelihood of horizontal gene transfer. Phylogenetic proximity and increased chances resulting from sharing the ecological niche provided by the amoeba host have likely had a major influence on the rate of gene exchange in Legionella. © 2010 The Author.
Shojaaddini M.,Tarbiat Modares University |
Lopez M.J.,Institute Cavanilles Of Biodiversitat I Biologia Evolutiva |
Moharramipour S.,Tarbiat Modares University |
Khodabandeh M.,Iran National Institute of Genetic Engineering and Biotechnology |
And 5 more authors.
Journal of Stored Products Research | Year: 2012
After several disease outbreaks in laboratory cultures of pyralid moths in Tabriz University, Iran, during 2004 and 2005, a new Bacillus thuringiensis aizawai strain EF495116 (BTA) was isolated from a dead Plodia interpunctella larva. A complete characterization of the strain was performed, including serological identification, protein and plasmid pattern determination, a PCR-based identification of virulence-related genes, nucleotide sequence analysis of the 16S rDNA and gyrB genes (in order to find out relationships between the species with other virulent Bacillus pathogens), and biological activity assays. These studies revealed that BTA produced a major parasporal protein band of about 135kDa, bore seven out of the fourteen pyralid-active genes analyzed (cry1Aa, cry1Ab, cry1C, cry1D, cry1I, cry2A and cry9) and was toxic against P.interpunctella and P.xylostella larvae, with LC 50 values of 7.13 and 3.1μg/mL, respectively. Although these features are common among other B.thuringiensis strains active on Lepidoptera, their role in epizootics is uncertain. However, sequence analysis of the 16S rDNA and gyrB genes revealed that BTA clustered with one of the few B.thuringiensis strains identified as a medical isolate. Interestingly, both strains, like many others reported to produce epizootics, belong to serovar aizawai. The implication of serovar or serovar-dependent genes in epizootics is discussed. © 2011 Elsevier Ltd.
Natalini A.,University of Pisa |
Natalini A.,ISI Sementi Research srl |
Vanesa M.-D.,Institute Cavanilles Of Biodiversitat I Biologia Evolutiva |
Ferrante A.,University of Milan |
Pardossi A.,University of Pisa
Acta Physiologiae Plantarum | Year: 2014
The shelf-life of fresh-cut tomatoes mainly depends on loss of tissue integrity and firmness that occurs also in intact fruits after long-term cold storage due to chilling injury. Round-fruit tomatoes (Solanum lycopersicum L.) cv. Jama were stored in 1.1-L plastic (polyethylene) fresh-cut produce containers as 10.0-mm-thick tomato slices and as intact tomatoes at 4 ± 0.5 °C. The aim of this work was to study the loss of membrane integrity and biochemical processes involved in membrane disruption. Electrolyte leakage and lipid peroxidation were studied at different stages of maturity: mature green, pink (PK), fully ripe and two different storage temperatures: 4 and 15 °C. The tomato slices of PK stage stored at 4 °C did not show changes for both parameters, while significant increase in membrane leakage and lipid peroxidation was observed at 15 °C, especially after 24 h of storage. The enzymes showed a simultaneous increase in their activities with a rise in electrolyte leakage and lipid peroxidation after 7 days of storage. Finally, phospholipase C (PLC) and phospholipase D (PLD) were investigated for intact fruit and tomato slices stored at 4 °C. The PLC had higher activity compared with PLD. In conclusion, the loss of membrane integrity in fresh-cut tomatoes is mainly affected by ripening stages, storage temperature and duration. The wounds enhance the PLC and PLD activities and they play a role late during storage. © 2013 Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków.