Biomedical subjects

E Olmo

Publications and source records attributed to E Olmo.

At least 19 recordsLinked to original sources

PubMed2006

Karyology of the Antarctic scallop Adamussium colbecki, with some comments on the karyological evolution of pectinids.

Karyotype, location of the nucleolar organiser region (NOR) and heterochromatin presence and composition were studied in the Antarctic scallop Adamussium colbecki Smith, 1902. The karyotype exhibits 2n = 38 chromosomes with 11 pairs of metacentrics, 5 of submetacentrics, one subtelocentric and two telocentrics. Ag-NOR, CMA(3), DA/MM and NOR-FISH evidenced paracentromeric NORs on the short arm of 2nd pair chromosomes. Digestion with three restriction endonucleases followed by sequential staining with Giemsa, CMA(3) and DAPI evidenced on all chromosomes centromeric heterochromatin positive for both DAPI and CMA(3). In situ hybridisation analysis showed the presence of an AT-rich satellite DNA in the centromeric heterochromatin of several chromosomes. A mosaicism was detected in the germinal cell lines of one specimen, as in six of the 20 plates examined the set had 37 chromosomes with a missing pair of telocentrics and an unpaired metacentric. Comparison of the chromosome sets of all the pectinids studied to date and comparison with a phyletic tree obtained from molecular mitochondrial genes studies yielded good agreement between karyotype morphology and taxonomic classification.

Animals↗

PubMed2005

Analysis of vitellogenin gene induction as a valuable biomarker of estrogenic exposure in various Mediterranean fish species.

Several pollutants have the potential to disrupt the endocrine system in aquatic organisms, and synthesis of vitellogenin (VTG) in male fish is a well-recognized effect of estrogenic xenobiotics. In this respect both the presence of the protein in plasma and the analysis of VTG gene induction may represent valuable biomarkers. The present article describes primers specifically designed for a RT-PCR assay of VTG mRNA in various Mediterranean fish species. All the species analyzed have great potential as bioindicators in the Mediterranean: the red mullet (Mullus barbatus) and the striped mullet (Mugil cephalus) are commonly found in coastal and estuarine waters, the black goby (Gobius niger) is an important species in harbors, the European eel (Anguilla anguilla) is more typical of brackish environments and lagoon ecosystems, and the tuna fish (Thunnus thynnus) has commercial value and, being a top predator in marine food webs, is particularly exposed to bioaccumulated halogenated hydrocarbons with possible estrogenic activity. The analysis of VTG mRNA has been standardized in feral fish, and basal expression of VTG was demonstrated in female specimens of the species analyzed. Only sexually immature specimens were analyzed for A. anguilla, and exposure to 17beta-estradiol clearly induced the synthesis of VTG mRNA, confirming their responsiveness to estrogenic exposure and the specificity of the designed primers. VTG mRNA was detected in adult males of T. thynnus (>100 kg), supporting estrogenic exposure of older specimens. In this species two different VTGs were identified, and the sequences obtained in the various species were compared with available sequences.

Amino Acid Sequence↗

PubMed2003

The chromosomal complement of the artedidraconid fish Histiodraco velifer (Perciformes: Notothenioidei) from Terra Nova Bay, Ross Sea.

The karyotype of Histiodraco velifer from the Antartic Ocean was analyzed using various banding methods and in situ hybridization with a telomeric probe. A male and a female had a diploid set of 46 chromosomes (6 submetacentric + 40 acrocentric, FN = 52); the nucleolar organizer was CMA3-positive and was located on the short arm of a medium-sized submetacentric pair. All chromosomes stained uniformly with DAPI, whereas C-banding revealed heterochromatic blocks that were mostly located centromerically and telomerically and were resistant to ALUI digestion. The substantial identity of the karyotype of H. velifer with that of the other artedidraconids investigated so far suggests that chromosome changes must have played a less than significant role in the speciation among the lineages of this fish family endemic to Antarctica.

Animals↗

PubMed2003

Reptiles: a group of transition in the evolution of genome size and of the nucleotypic effect.

A comparison between genome size and some phenotypic parameters, such as developmental length and metabolic rate, showed in reptiles a nucleotypic correlation similar to the one observed in birds and mammals. Indeed, like homeotherms, reptiles exhibit a highly significant, inverse correlation of genome size with metabolic rate but unlike amphibians, no relationship with developmental length. Several lines of evidence suggest that these nucleotypic correlations are influenced by body temperature, which also affects the guanine + cytosine nuclear percentage, and that they play an important role in the adaptation of these amniotes. However, the reptilian suborders exhibit differences in the quantitative and compositional characters of the genome that do not completely correspond to differences in the phenotypic parameters commonly involved in the nucleotypic effect. Thus, additional factors could have influenced genome size in this class. These data could be explained with the model of Hartl and Petrov, who observed an inverse correlation between genome size, non-coding portion of the genome and rate of DNA loss and hypothesized a strong role for different spectra of spontaneous insertions and deletions (indels) in the variations of genome size. It is thus reasonable to surmise that variations in the reptilian genome were initially influenced by different indels spectra typical of the diverse lineages, possibly related to different chromosome compartmentalizations. The consequent size increases or decreases would have influenced various morphological and functional cell parameters, and through these some phenotypic characteristics of the whole organism, especially the metabolic rate, very important for environmental adaptation and thus subject to natural selection. Through this "nucleotypic" bond, natural selection would also have controlled genome size variations.

Adaptation, Physiological↗

PubMed2003

Chromosome banding and molecular cytogenetic study of two Mediterranean trachinoid fish species (Teleostei: Trachinidae, Uranoscopidae).

The chromosomes of Echiichthys vipera (Trachinidae) and Uranoscopus scaber (Uranoscopidae) were analyzed by means of various banding methods and fluorescence in situ hybridization (FISH) with telomeric and major rDNA probes, respectively. The karyotype of E. vipera was composed of 48 acrocentric chromosomes and NOR sites, as revealed by all detection methods, were situated pericentromerically on a single pair of middle-sized chromosomes. Blocks of constitutive heterochromatin were present in the pericentromeric regions of all pairs of chromosomes. The karyotype of U. scaber showed three karyomorphs: 2n = 30 (18 m + 12 a/st [m = metacentric, a = acrocentric and st = subtelocentric]), 2n = 28 (20 m + 8 a/st), 2n = 27 (21 m + 6 a/st). NORs, as revealed by FISH, were situated pericentromerically on a single pair of middle-sized chromosomes in spite of Ag-positive signals in the centromeres of all pairs of chromosomes. Robertsonian fusions were hypothesized for observed variation due to invariable number of chromosome arms FN = 48.

Animals↗

PubMed2002

Different genomic evolutionary rates in the various reptile lineages.

Although Reptiles occupy a strategic position among terrestrial vertebrates, studies of the composition and evolution of their genome are scarce. The cytogenetic analysis of nearly 1400 species evidenced different karyotypical evolutionary rates and different G-banding structures in turtles and crocodiles on the one hand and squamates on the other. A similar dichotomy was also identified through the study of the quantitative and compositional characteristics of the genome. The different evolutionary rates of chromosome morphology and genome size and composition and the diversification of coding and non-coding sequences bear an interesting relationship to the number of extant species and the extinction rates of the reptilian orders and suborders studied, suggesting a large role for such different evolutionary rates in the phylogenesis of this class. The different molecular and structural organisation of chromosomes could be an important, though by no means the sole, factor affecting the genome's evolutionary rate.

Alligators and Crocodiles↗

PubMed2002

Chromosomal studies on ten species of notothenioid fishes (Notothenioidei: Bathydraconidae, Channichthyidae, Nototheniidae).

The results of a cytogenetic study conducted with banding and in situ hybridization techniques using ribosomal and telomeric probes on various species belonging to three families (Bathydraconidae, Channichthyidae and Nototheniidae) of the perciform suborder, Notothenioidei, are reported. The heterochromatin distribution and composition, nucleolar organiser and localisation of telomeric sequences seem to indicate that both in karyologically conservative families such as channichthyids and in families exhibiting greater karyological variability, certain DNA fractions like ribosomal genes and centromeric and telomeric DNAs are prone to some variability. This could play an important role in favouring or hampering chromosome rearrangements.

Animals↗

PubMed2001

A molecular phylogeny of Heterodonta (Bivalvia) based on small ribosomal subunit RNA sequences.

Within Heterodonta, phylogenesis has so far been studied almost exclusively on the basis of morphological data. Results have often been discordant, and an exhaustive molecular approach has not yet been attempted. The present study was undertaken to clarify the phylogenetic relationships obtaining among Heterodonta families through the analysis of 18S rRNA gene. To do this, the whole sequence of this gene was analyzed in 29 species of eight superfamilies of the order of Veneroida (Arcticoidea, Cardioidea, Galeommatoidea, Mactroidea, Solenoidea, Tellinoidea, Tridacnoidea, and Veneroidea) and in two superfamilies of Myoida (Pholaloidea and Myoidea). The study was extended by constructing phylogenetic trees using partial sequences. This strategy made it possible to include 11 additional species by introducing three further superfamilies: Chamoidea, Corbiculoidea, and Hiatellinoidea. At variance with the conclusions reached on the basis of morphological features, the molecular data clearly show that the Myoida species included in this study belong to Veneroida, thus undermining the legitimacy of the division of Heterodonta into two orders, and that considerable differences in the phylogenetic relationships obtain among superfamilies.

Animals↗

PubMed2001

Cytogenetics of nine species of mediterranean blennies and additional evidence for an unusual multiple sex-chromosome system in Parablennius tentacularis (Perciformes, Blenniidae).

The chromosomal complements of nine species of Blenniidae (Aidablennius sphylnx, Blennius ocellaris, Lypophris adriaticus, L. pavo, L. trigloides, Parcablennius gattorugine, P. ponticus, P. sanguinolentus, P. tentacularis) from the Adriatic Sea were analysed with several banding methods and in-situ hybridization. In all species, the diploid set consists of 48 mostly acrocentric chromosomes and has a similar location (terminal centromeric) of NORs, except for L. pavo (interstitial pericentric) and P. ponticus (terminal on the long arm). There are major differences in karyotype with regard to the amount and distribution of heterochromatin. Parablennius tentacularis shows a distinctive sex-chromosome system involving 2n = 48 males with a large totally heterochromatic Y chromosome, and males with 2n = 47. This difference is likely to be the consequence of a translocation of an autosome on the original Y. This finding constitutes an additional instance of the great variability in origins of multiple sex chromosome systems in vertebrates.

Animals↗

PubMed2000

A satellite DNA containing CENP-B box-like motifs is present in the antarctic scallop Adamussium colbecki.

The DNA of the Antarctic scallop Adamussium colbecki was found to contain a highly repeated sequence identifiable upon restriction with endonuclease BglII. The monomeric unit - denominated pACS (about 170bp long) - was cloned. Southern blot hybridization yielded a ladder-like banding pattern, indicating that the repeated elements are tandemly arranged in the genome and therefore represent a sequence of satellite DNA. Sequence analysis of five different clones revealed the presence of various subfamilies, some of which showed a high degree of divergence. In each clone, regions homologous to the mammalian CENP-B box were observed. A region homologous to the CDEIII centromeric sequence of yeast was also found in one of the clones. These observations suggest a relationship of the pACS family to the centromeric area in A. colbecki.

Animals↗

PubMed2000

The effects of nitroxide radicals on oxidative DNA damage.

The indolinonic and quinolinic aromatic nitroxides synthesized by us are a novel class of biological antioxidants, which afford a good degree of protection against free radical-induced oxidation in different lipid and protein systems. To further our understanding of their antioxidant behavior, we thought it essential to have more information on their effects on DNA exposed to free radicals. Here, we report on the results obtained after exposure of plasmid DNA and calf thymus DNA to peroxyl radicals generated by the water-soluble radical initiator, 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH), and the protective effects of the aromatic nitroxides and their hydroxylamines, using a simple in vitro assay for DNA damage. In addition, we also tested for the potential of these nitroxides to inhibit hydroxyl radical-mediated DNA damage inflicted by Fenton-type reactions using copper and iron ions. The commercial aliphatic nitroxides 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL), and bis(2,2, 6,6-tetramethyl-1-oxyl-piperidin-4-yl)sebacate (TINUVIN 770) were included for comparison. The results show that the majority of compounds tested protect: (i) both plasmid DNA and calf thymus DNA against AAPH-mediated oxidative damage in a concentration-dependent fashion (1-0.1 mM), (ii) both Fe(II) and Cu(I) induced DNA oxidative damage. However, all compounds failed to protect DNA against damage inflicted by the presence of the transition metals in combination with H(2)O(2). The differences in protection between the compounds are discussed in relation to their molecular structure and chemical reactivity.

Amidines↗

PubMed2000

Molecular data from the 16S rRNA gene for the phylogeny of Pectinidae (Mollusca: Bivalvia).

The phylogenetic relationships among the species belonging to the family Pectinidae are still an issue of debate. The mitochondrial DNA sequences from the large ribosomal RNA gene may be of great value for systematic and phylogenetic studies within families. Partial sequences of the 16S rRNA gene were obtained for the scallop species Adamussium colbecki, Aequipecten opercularis, Chlamys glabra, C. islandica, C. varia, and Pecten jacobeus and compared with the published sequence of Pecten maximus. The present molecular data show that Chlamys are polyphyletic and do not support the assignment of these species to the two subfamilies Chlamydinae and Pectininae. Moreover, the minimal genetic distance between P. maximus and P. jacobeus suggests that they could belong to the same species.

Animals↗

PubMed1999

The small-subunit rRNA gene sequences of venerids and the phylogeny of bivalvia.

The complete nucleotide sequence of the 18S subunit of ribosomal DNA (rDNA) was determined for the venerid clams Callista chione (Pitarinae) and Venus verrucosa (Venerinae). Comparison of the new sequences with the published sequences of 1 annelid, 2 gastropods, 2 polyplacophorans, and 19 bivalves showed that when the annelids are used as outgroup the gastropods diverge from the bivalves, which form a cluster including the polyplacophorans. When the gastropods alone were compared with the bivalves, the latter split in two groups corresponding to the two subclasses of Heterodonta and Pteriomorpha. The former include two taxa that diverged early, Galeomma and Tridacna, while the Veneridae and Mactridae form two sister groups. In contrast to previous reports and in line with morphological data, the Ostreidae are included in the Pteriomorphia and form a monophyletic group.

Animals↗

PubMed1998

An alphoid-like satellite DNA sequence is present in the genome of a lacertid lizard.

A PstI DNA family was isolated from the genome of a lacertid, Lacerta graeca. The 185-bp monomeric unit (pGPS) was cloned and hybridized to DNAs and chromosomes of several lacertid species. The data showed that pGPS hybridizes to the (1) centromeric or pericentromeric heterochromatin of almost all the chromosomes of L. graeca and (2) genomic DNA of species phylogenetically related and unrelated to L. graeca. The presence of pGPS even in species immunologically apart more than 30 million years suggests that this repeated family might be either very ancient or have been conserved during evolution due to its functional role. The latter hypothesis might be supported by the results of sequence analysis which showed some homology with both several alphoid sequences of primates and the CDEIII centromeric sequence of yeast. Segments of the satellite sequence are similar to the mammalian CENP-B box. These observations suggest that pGPS might have a role in determining the centromeric function in lacertid lizards.

Animals↗

PubMed1998

Cytogenetic studies in some species of Scorpaeniformes (Teleostei: Percomorpha).

Cytogenetic studies were performed in four species of two scorpaeniform teleost families: Scorpaenidae and Triglidae. The karyotypes of Trigla lucerna, Trigloporus lastoviza (Triglidae), Scorpaena porcus and S. notata (Scorpaenidae) were analysed using various banding methods and in situ hybridization with a telomeric probe. In the two Scorpaena species, modest morphological divergence corresponded to considerable karyotype reorganization, while in the two Triglidae substantial phenotypical divergence corresponded to limited chromosomal changes. These data stress the need for a taxonomical re-evaluation of these teleosts based on characters independent of morphology.

Animals↗

PubMed1997

Heterochromatin heterogeneity and chromosome variability in four species of gobiid fishes (Perciformes:Gobiidae).

A karyological study of four species of gobiid fishes, Gobius niger, G. paganellus, G. cobitis, and Zosterisessor ophiocephalus (Perciformes, Gobiidae), was conducted by standard, fluorochrome staining (using chromomycin A3, mithramycin, and DAPI), Alu-I digestion, and CBG- and RBG-banding methods. Our cytogenetic data indicate that heterochromatin in these taxa is highly differentiated, exhibiting heterogeneity in staining characteristics, and presumably in underlying DNA sequences, and a different capability for promoting Robertsonian fusions.

Animals↗

PubMed1996

Phylogenetic analysis of Veneridae (Bivalvia): comparison of molecular and palaeontological data.

An approximately 400-bp-long portion of the 16s rRNA gene sequence has been determined for the venerid clams Chamelea gallina (Chioninae), Dosinia lupinus (Dosiniinae), Pitar rudis, Callista chione (Pitarinae), Tapes decussatus, T. philippinarum, Venerupis (= Paphia) aurea (Tapetinae), and Venus verrucosa (Venerinae). Neighbor-joining and maximum parsimony trees support the results of traditional classification methods at the subfamily level but do not support the concept of a genus Tapes. The transversion divergence rate estimated on the basis of the palaeontological record for the C. gallina/V. verrucosa separation and for the Pitarinae is very close (0.14-0.16% per Myr, respectively) to that of ungulates and cetaceans, while the Tapetinae exhibit a much higher (0.36% per Myr) rate.

Animals↗

PubMed1994

Further data on the occurrence and evolution of satellite DNA families in the lacertid genome.

This paper reports the isolation and characterization of two HindIII repetitive DNA families from the genome of two lacertid lizards, Podarcis sicula and Lacerta saxicola. These satellites did not appear to be related to each other. The consensus sequences of their monomeric units did not show any similarity, though both DNAs were A-T rich. Moreover, each of them was found only in closely related species. The monomeric unit of the HindIII DNA family isolated from P. sicula (pLHS) showed a close resemblance to pLCS, a centromeric satellite DNA previously isolated from the same species; it was, however, mainly localized at pericentromeric, interstitial and telomeric levels. The results also provide interesting information on the systematics of the lacertids studied.

Animals↗