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  • 1
    Electronic Resource
    Electronic Resource
    Localization of a vertebrate telomeric sequence in the chromosomes of two marine worms (phylum Annelida: class polychaeta) (1995)
    Springer
    Chromosome research 3 (1995), S. 507-508 
    Details
    ISSN: 1573-6849
    Keywords: karyotype evolution ; Platynereis dumerilii ; polychaete chromosomes ; Pomatoceros lamarckii ; telomeric (TTAGGG) n sequence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Using the fluorescencein situ hybridization (FISH) technique, the presence of the vertebrate telomeric sequence (TTAGGG) n was found in the chromosomes of two marine polychaetes belonging to two separate orders: one errant,Platynereis dumerilii (family Nereidae), and the other sessile,Pomatoceros lamarckii (family Serpulidae). This sequence was exclusively present at the ends of the chromosomes in both species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00713966
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    Paper (German National Licenses)
    Fulltext
  • 2
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    Metal speciation and toxicity of Tamar Estuary water to larvae of the Pacific oyster, Crassostrea gigas (2011)
    Elsevier
    In:  Marine Environmental Research, 72 (1-2). pp. 3-12.
    Details
    Publication Date: 2014-01-27
    Description: As part of the PREDICT Tamar Workshop, the toxicity of estuarine waters in the Tamar Estuary (southwest England) was assessed by integration of metal speciation determination with bioassays. High temporal resolution metal speciation analysis was undertaken in situ by deployment of a Voltammetric In situ Profiling (VIP) system. The VIP detects Cd (cadmium), Pb (lead) and Cu (copper) species smaller than 4 nm in size and this fraction is termed 'dynamic' and considered biologically available. Cadmium was mainly present in the dynamic form and constituted between 56 and 100 of the total dissolved concentration, which was determined subsequently in the laboratory in filtered discrete samples. In contrast, the dynamic Pb and Cu fractions were less important, with a much larger proportion of these metals associated with organic ligands and/or colloids (45-90 Pb and 46-85 Cu), which probably reduced the toxicological impact of these elements in this system. Static toxicity tests, based on the response of Crassostrea gigas larva exposed to discrete water samples showed a high level of toxicity (up to 100 abnormal development) at two stations in the Tamar, particularly during periods of the tidal cycle when the influence of more pristine coastal water was at its lowest. Competitive ligand-exchange Cu titrations showed that natural organic ligands reduced the free cupric ion concentration to levels that were unlikely to have been the sole cause of the observed toxicity. Nonetheless, it is probable that the combined effect of the metals determined in this work contributed significantly to the bioassay response. © 2011 Elsevier Ltd.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.marenvres.2011.05.001
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 3
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    Changes in expression profiles of genes associated with DNA repair following induction of DNA damage in larval zebrafish Danio rerio (2013)
    Oxford University Press
    Details
    Publication Date: 2013-08-15
    Description: DNA repair is initiated by transcription of genes in response to specific types of damage. Breaks in DNA strands (single and double) are repaired predominantly through non-homologous end-joining (NHEJ) or homologous recombination (HR), but progression of repair and changes in expression profiles of genes involved are unknown. DNA damage was induced in zebrafish larvae by brief exposure (10min) to hydrogen peroxide (H 2 O 2 ; 100mM), and induction of DNA strand breaks was assessed by single-cell gel electrophoresis (comet) assay over 24h. H 2 O 2 was selected because it is eliminated rapidly after induction of DNA damage. DNA damage [mean ± standard error of the mean (SEM), % tail DNA] increased significantly immediately after 10-min H 2 O 2 exposure (35.4±3.8; control 17.2±2.0), but damage did not differ from control levels 24h after exposure (9.2±0.4; control 9.9±0.9). At 0-, 1-, 3-, 6-, 12- and 24-h post-exposure, quantitative reverse transcriptase–PCR was conducted to assess expression of selected genes involved in DNA repair including xrcc5 , xrcc6 (NHEJ), rad51 (HR) and gadd45a (DNA damage detection). Expression (maximum fold-change ± SEM, triplicate samples of 40 larvae) of each gene increased rapidly (within 6h) after exposure to 100mM of H 2 O 2 : 1.8±0.2, rad51 ; 1.7±0.2, xrcc5 and 1.5±0.1, xrcc6. Acute exposure (200mM of H 2 O 2 ) caused 10% larval mortality within 2h, upregulated gadd45a (5.0±0.8), but did not change expression of rad51, xrcc5 or xrcc6 . Expression profiles (critical exponential model) were similar among genes but differed relative to time and among independent experiments. Results indicate that repair mechanisms are initiated rapidly after DNA damage, that gene expression profiles vary according to potency of H 2 O 2 exposure and that examination of the time course of gene expression changes is necessary to understand the complete gene response over time.
    Print ISSN: 0267-8357
    Electronic ISSN: 1464-3804
    Topics: Biology , Medicine
    Published by Oxford University Press
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  • 4
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    MBL2 Variations and Malaria Susceptibility in Indian Populations [Host Response and Inflammation] (2013)
    The American Society for Microbiology (ASM)
    Details
    Publication Date: 2013-12-19
    Description: Human mannose-binding lectin (MBL) encoded by the MBL2 gene is a pattern recognition protein and has been associated with many infectious diseases, including malaria. We sought to investigate the contribution of functional MBL2 gene variations to Plasmodium falciparum malaria in well-defined cases and in matched controls. We resequenced the 8.7 kb of the entire MBL2 gene in 434 individuals clinically classified with malaria from regions of India where malaria is endemic. The study cohort included 176 patients with severe malaria, 101 patients with mild malaria, and 157 ethnically matched asymptomatic individuals. In addition, 830 individuals from 32 socially, linguistically, and geographically diverse endogamous populations of India were investigated for the distribution of functional MBL2 variants. The MBL2 –221C ( X ) allelic variant is associated with increased risk of malaria (mild malaria odds ratio [OR] = 1.9, corrected P value [ P Corr ] = 0.0036; severe malaria OR = 1.6, P Corr = 0.02). The exon1 variants MBL2*B (severe malaria OR = 2.1, P Corr = 0.036; mild versus severe malaria OR = 2.5, P Corr = 0.039) and MBL2*C (mild versus severe malaria OR = 5.4, P Corr = 0.045) increased the odds of having malaria. The exon1 MBL2*D/*B/*C variant increased the risk for severe malaria (OR = 3.4, P Corr = 0.000045). The frequencies of low MBL haplotypes were significantly higher in severe malaria (14.2%) compared to mild malaria (7.9%) and asymptomatic (3.8%). The MBL2*LYPA haplotypes confer protection, whereas MBL2*LXPA increases the malaria risk. Our findings in Indian populations demonstrate that MBL2 functional variants are strongly associated with malaria and infection severity.
    Print ISSN: 0019-9567
    Electronic ISSN: 1098-5522
    Topics: Medicine
    Published by The American Society for Microbiology (ASM)
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  • 5
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    Assessment of oxidative damage to DNA, transcriptional expression of key genes, lipid peroxidation and histopathological changes in carp Cyprinus carpio L. following exposure to chronic hypoxic and subsequent recovery in normoxic conditions (2014)
    Oxford University Press
    Details
    Publication Date: 2014-12-20
    Description: In fish, a complex set of mechanisms deal with environmental stresses including hypoxia. In order to probe the hypothesis that hypoxia-induced stress could be manifested in varieties of pathways, a model species, mirror carp ( Cyprinus carpio ), were chronically exposed to hypoxic condition (dissolved oxygen level: 1.80±0.6mg/l) for 21 days and subsequently allowed to recover under normoxic condition (dissolved oxygen level: 8.2±0.5mg/l) for 7 days. At the end of these exposure periods, an integrated approach was applied to evaluate several endpoints at different levels of biological organisation. These included determination of (i) oxidative damage to DNA in erythrocytes (using modified comet assay), (ii) lipid peroxidation in liver samples by measuring the malondialdehyde production using the 2-thiobarbituric acid [i.e. thiobarbituric acid reactive substances (TBARS) assay] and (iii) histopathological changes in gills. In addition, transcriptional expression of hypoxia-inducible factor 1 α ( HIF-1α ) and genes involved in the repair of oxidative damage to DNA (i.e. ogg1 ) and base excision repair (i.e. xrcc1 ) using reverse transcription polymerase chain reaction in liver samples were also determined. The results suggested significantly enhanced expression of these genes in response to hypoxia compared to concurrent normoxic controls. While the expression of HIF-1α reverted to control values within 7 days exposure to normoxic condition ( P 〈 0.05), the transcriptional expression of the two genes involved in DNA repair process remained significantly high under the recovery period, which complemented the induction of oxidative damage to DNA. Hypoxic groups showed significantly increased values for TBARS level (~2-fold) and histopathological changes in gill tissues compared to both normoxic and recovery groups. Overall, oxidative damage to DNA determined by modified comet assay reflected the observed biological responses in other tissues of the fish. Along with other parameters, this integrated experimental design further strengthens the applications of the comet assay as an important technique to assess stress-induced DNA damage in ecotoxicological studies.
    Print ISSN: 0267-8357
    Electronic ISSN: 1464-3804
    Topics: Biology , Medicine
    Published by Oxford University Press
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  • 6
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    Integrated biological responses and tissue-specific expression of p53 and ras genes in marine mussels following exposure to benzo({alpha})pyrene and C60 fullerenes, either alone or in combination (2016)
    Oxford University Press
    Details
    Publication Date: 2016-12-24
    Description: We used the marine bivalve ( Mytilus galloprovincialis ) to assess a range of biological or biomarker responses following exposure to a model-engineered nanoparticle, C 60 fullerene, either alone or in combination with a model polycyclic aromatic hydrocarbon, benzo(α)pyrene [B(α)P]. An integrated biomarker approach was used that included: (i) determination of ‘clearance rates’ (a physiological indicator at individual level), (ii) histopathological alterations (at tissue level), (iii) DNA strand breaks using the comet assay (at cellular level) and (iv) transcriptional alterations of p53 (anti-oncogene) and ras (oncogene) determined by real-time quantitative polymerase chain reaction (at the molecular/genetic level). In addition, total glutathione in the digestive gland was measured as a proxy for oxidative stress. Here, we report that mussels showed no significant changes in ‘clearance rates’ after 1 day exposure, however significant increases in ‘clearance rates’ were found following exposure for 3 days. Histopathology on selected organs (i.e. gills, digestive glands, adductor muscles and mantles) showed increased occurrence of abnormalities in all tissues types, although not all the exposed organisms showed these abnormalities. Significantly, increased levels of DNA strand breaks were found after exposure for 3-days in most individuals tested. In addition, a significant induction for p53 and ras expression was observed in a tissue and chemical-specific pattern, although large amounts of inter-individual variability, compared with other biomarkers, were clearly apparent. Overall, biological responses at different levels showed variable sensitivity, with DNA strand breaks and gene expression alterations exhibiting higher sensitivities. Furthermore, the observed genotoxic responses were reversible after a recovery period, suggesting the ability of mussels to cope with the toxicants C 60 and/or B(α)P under our experimental conditions. Overall, in this comprehensive study, we have demonstrated mussels as a suitable model marine invertebrate species to study the potential detrimental effects induced by possible genotoxicants and toxicants, either alone or in combinations at different levels of biological organisation (i.e. molecular to individual levels).
    Print ISSN: 0267-8357
    Electronic ISSN: 1464-3804
    Topics: Biology , Medicine
    Published by Oxford University Press
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