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  • 1
    Electronic Resource
    Electronic Resource
    Coal mine workers' pneumoconiosis (1997)
    Springer
    Environmental geology 30 (1997), S. 72-80 
    Details
    ISSN: 1432-0495
    Keywords: Key words Coal mine workers' pneumoconiosis ; Coalification ; Macerals ; Organic compounds ; Phenols
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  The fibrogenic and cytotoxic potential of coal mine dust is independent of the amount of quartz and other inorganic parameters. Results of coal petrographical and organic geochemical investigations of coals and coal mine dust from the Ruhr and Ibbenbüren Region of Germany demonstrate variations of organic dust amount possibly influencing these noxious properties. Coal mine dust of high rank coals is characterized by a pronounced fibrogenic risk. This risk, independent of the quantity of quartz, is probably based on shape variations of different coal macerals. With increasing coalification of the corresponding seam, the vitrinite is enriched in its dust; however, lower concentrations have been determined for inertinite. Vitrinite shows constant shapes and sizes independent of the rank of coal. Inertinite particles with elongated to fibrous shapes tend to larger sizes with increasing coalification. Strikingly, coal mine dust from miners' lungs with high degrees of coal mine workers' pneumoconiosis (CWP) is enriched in inertinite. In contrast, high cytotoxicities in cell tests are known for coal mine dust from low coalified coals. High concentrations of phenolic compounds can be extracted by dichloromethane from low coalified coal mine dust. These compounds, which are characterized by a high water solubility and therefore high bioavailability, explain the high cytotoxicities of coal mine dust. Contamination of dust by diesel emissions in the coal mine can act as additionally supporting parameters for extended cytotoxicities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002540050134
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  • 2
    Electronic Resource
    Electronic Resource
    Ancient and Recent Horizontal Invasions of Drosophilids by P Elements (2000)
    Springer
    Journal of molecular evolution 51 (2000), S. 577-586 
    Details
    ISSN: 1432-1432
    Keywords: Key words:P element — Transposon evolution — Horizontal transfer —Drosophila—Scaptomyza—Lordiphosa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. P elements of two different subfamilies designated as M- and O-type are thought to have invaded host species in the Drosophila obscura group via horizontal transmission from external sources. Sequence comparisons with P elements isolated from other species suggested that the horizontal invasion by the O-type must have been a rather recent event, whereas the M-type invasion should have occurred in the more distant past. To trace the phylogenetic history of O-type elements, additional taxa were screened for the presence of O- and M-type elements using type-specific PCR primers. The phylogeny deduced from the sequence data of a 927-bp section (14 taxa) indicate that O-type elements have undergone longer periods of regular vertical transmission in the lineages of the saltans and willistoni groups of Drosophila. However, starting from a species of the D. willistoni group they were transmitted horizontally into other lineages. First the lineage of the D. affinis subgroup was infected, and finally, in a more recent wave of horizontal spread, species of three different genera were invaded by O-type elements from the D. affinis lineage: Scaptomyza, Lordiphosa, and the sibling species D. bifasciata/D. imaii of the Drosophila obscura subgroup. The O-type elements isolated from these taxa are almost identical (sequence divergence 〈1%). In contrast, no such striking similarities are observed among M-type elements. Nevertheless, the sequence phylogeny of M-type elements is also not in accordance with the phylogeny of their host species, suggesting earlier horizontal transfer events. The results imply that P elements cross species barriers more frequently than previously thought but require a particular genomic environment and thus seem to be confined to a rather narrow spectrum of host species. Consequently, different P element types acquired by successive horizontal transmission events often coexist within the same genome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002390010121
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  • 3
    Electronic Resource
    Electronic Resource
    Structural setting, hydrothermal alteration, and gold mineralisation at the Archaean syenite-hosted Jupiter deposit, Yilgarn Craton, Western Australia (2000)
    Springer
    Mineralium deposita 35 (2000), S. 402-421 
    Details
    ISSN: 1432-1866
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The Jupiter gold deposit in the northeastern Eastern Goldfields Province of the Yilgarn Craton of Western Australia is hosted in greenschist facies metamorphosed tholeiitic basalt, quartz–alkali-feldspar syenite, and quartz–feldspar porphyry. Syenite intrudes basalt as irregularly shaped dykes which radiate from a larger stock, whereas at least three E–W and NE–SW striking quartz–feldspar porphyries intrude both syenite and basalt. Brittle–ductile shear zones are shallow-dipping, NW to NE striking, or are steep-dipping to the south and west. Quartz ± carbonate veins that host gold at Jupiter occur in all lithologies and are divided into: (1) veins that are restricted to the shear zones, (2) discrete veins that are subparallel to shear zone-hosted veins, and (3) stockwork veins that form a network of randomly oriented microfractures in syenite wallrock proximal to shallow-dipping shear zones. The gold-bearing veins comprise mainly quartz, calcite, ankerite, and albite, with minor sericite, pyrite, chalcopyrite, galena, sphalerite, molybdenite, telluride minerals, and gold. Proximal hydrothermal alteration zones to the mineralised veins comprise quartz, calcite, ankerite, albite, and sericite. High gold grades (〉2 g/t Au) occur mainly in syenite and in the hanging walls to shallow-dipping shear zones in syenite where there is a greater density of mineralised stockwork veins. The Jupiter deposit has structural and hydrothermal alteration styles that are similar to both granitoid-hosted, but post-magmatic Archaean lode-gold deposits in the Yilgarn Craton and intrusion-related, syn-magmatic, syenite-hosted gold deposits in the Superior Province of Canada. Based on field observations and petrologic data, the Jupiter deposit is considered to be a post-magmatic Archaean lode-gold deposit rather than a syn-intrusion deposit.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001260050252
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  • 4
    Electronic Resource
    Electronic Resource
    Thin-skinned thrust mineralization in the Brasília fold belt: the example of the old Luziânia gold deposit (1992)
    Springer
    Mineralium deposita 27 (1992), S. 293-303 
    Details
    ISSN: 1432-1866
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The Luziânia gold deposits in southern Goiás lie within the Late Proterozoic Brasília fold belt. The rocks that host the gold mineralization are a monotonous series of hydrothermally altered phyllites that have been subject to low grade regional metamorphism. The major controls on the gold mineralization are northeast trending and gently northwest dipping ductile-brittle, dextral-reverse shear zones associated with regional thin-skinned thrusting of the Canastra Group. From a preliminary fluid inclusion study it is deduced that low salinity, ⩽ 7 eq. wt% NaCl, moderately dense, H2O-CO2 ± CH4 ore fluids deposited gold at temperatures of 300 ± 75°C and pressures of 1.5 to 3 kb in the filling stage of the vein formation. Post-filling stage gold deposition probably occured by mixing of fluids at higher crustal levels (1.5–2 kb). During thrusting, prograde metamorphism released pore water which penetrated along thrust planes that acted as high permeability zones for the ponding and release, by hydraulic fracturing, of overpressured fluids. Later in the tectonic evolution and at shallower crustal levels, there was likely an incursion of near suface water into the fault zone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00193400
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  • 5
    Electronic Resource
    Electronic Resource
    A classification scheme for epigenetic Archaean lode-gold deposits (1995)
    Springer
    Mineralium deposita 30 (1995), S. 408-410 
    Details
    ISSN: 1432-1866
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Recent research has shown that Archaean lode-gold deposits occur in environments that range in their metamorphic grade from prehnite-pumpellyite to lower granulite facies. Based on this data a new classification is proposed for these deposits. In this classification, shallow-level gold deposits are classed as epizonal, the so-called “mesothermal” deposits are mesozonal, and the deeper deposits, commonly in mid-amphibolite or lower-granulite terrains, are hypozonal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00202283
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  • 6
    Electronic Resource
    Electronic Resource
    Hydrothermal origin for the 2 billion year old Mount Tom Price giant iron ore deposit, Hamersley Province, Western Australia (1999)
    Springer
    Mineralium deposita 34 (1999), S. 784-789 
    Details
    ISSN: 1432-1866
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Giant iron-ore deposits, such as those in the Hamersley Province of northwestern Australia, may contain more than a billion tonnes of almost pure iron oxides and are the world's major source of iron. It is generally accepted that these deposits result from supergene oxidation of host banded iron formation (BIF), accompanied by leaching of silicate and carbonate minerals. New textural evidence however, shows that formation of iron ore at one of those deposits, Mount Tom Price, involved initial high temperature crystallisation of magnetite-siderite-iron silicate assemblages. This was followed by development of hematite- and ferroan dolomite-bearing assemblages with subsequent oxidation of magnetite, leaching of carbonates and silicates and crystallisation of further hematite. Preliminary fluid inclusion studies indicate both low and high salinity aqueous fluids as well as complex salt-rich inclusions with the range of fluid types most likely reflecting interaction of hydrothermal brines with descending meteoric fluids. Initial hematite crystallisation occurred at about 250 °C and high fluid pressures and continued as temperatures decreased. Although the largely hydrothermal origin for mineralisation at Mount Tom Price is in conflict with previously proposed supergene models, it remains consistent with interpretations that the biosphere contained significant oxygen at the time of mineralisation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001260050238
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  • 7
    Electronic Resource
    Electronic Resource
    P-related sequences inDrosophila bifasciata: A molecular clue to the understanding of P-element evolution in the genusDrosophila (1990)
    Springer
    Journal of molecular evolution 31 (1990), S. 478-484 
    Details
    ISSN: 1432-1432
    Keywords: P-element evolution ; Drosophila bifasciata ; Recent invasion hypothesis ; Horizontal gene transfer ; Sequence divergence ; Substitution rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two P-elements (bif1 and bif2) were isolated from a genomic library ofDrosophila bifasciata. Both elements are internally deleted and have lost the coding capacity for a functional transposase. One of the elements (bif2) contains an insert consisting of a repetitive sequence. The terminal inverted repeats and the segments necessary for passive mobility are well conserved. Element bif2 has retained rudiments of the coding sequence of exon 0 and exon 3, but the reading frame is destroyed by insertions and deletions. The comparison of theD. bifasciata P-elements with P-elements ofDrosophila melanogaster andDrosophila nebulosa reveals that the two latter sequences are more similar to each other than either of them is to theD. bifasciata elements. This finding contradicts the phylogenetic relationship of the species and can be taken as an indirect but unequivocal evidence for recent horizontal gene transfer from a relative ofD. nebulosa to the gene pool ofD. melanogaster. The P-elements ofD. bifasciata are phylogenetically ancient and have evolved independently for about 50 million years. A higher substitution rate at the third codon position as well as a predominance of conservative replacements at the amino acid level indicates that the P-elements ofD. bifasciata have been under selective constraint over a long period and that immobilization has occurred only recently.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02102074
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  • 8
    Electronic Resource
    Electronic Resource
    Transcription and Splicing Patterns of M- and O-Type P Elements in Drosophila bifasciata, D. helvetica, and Scaptomyza pallida (1998)
    Springer
    Journal of molecular evolution 46 (1998), S. 542-551 
    Details
    ISSN: 1432-1432
    Keywords: Key words:Drosophila—Scaptomyza—P element — RT-PCR — Expression — Splicing pattern
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. RT-PCR was applied to analyze the splicing patterns of P-element-derived mRNAs in Drosophila bifasciata, D. helvetica, and Scaptomyza pallida. D. melanogaster was used as a control. The experiments revealed that P elements are transcribed in all species investigated. However, there are differences in the splicing patterns of IVS3, which has to be removed in order to produce transposase mRNA instead of repressor mRNA. These differences are observed among species as well as between the P element subfamilies, the M and the O type, which coexist in the genomes of D. bifasciata and S. pallida. In D. helvetica M-type transposase mRNA was found in the germline and repressor mRNA in the soma, as has been previously described for the canonical (M-type-related) P element of D. melanogaster. In contrast, in S. pallida only repressor mRNA of M-type elements was detected in all tissues. In D. bifasciata, M-type IVS3, although activated both in the soma and the germline, is never completely excised. Instead, two alternative double-spliced variants occur in which two small introns are removed within the IVS3 region. One of these variants codes for a protein 12 aa longer than the regular transposase. Taking these findings together, transposase production and transpositional activity of M-type elements seem to be limited to D. helvetica and D. melanogaster, whereas M-type elements have become immobile in D. bifasciata and S. pallida. Unlike the M type, the splicing of O-type transcripts in D. bifasciata and S. pallida follows the classical rules of tissue-specific P element regulation: transposase mRNA is produced exclusively in the germline whereas repressor mRNA is formed in somatic cells. Thus O-type elements are thought to be still transpositionally active in both species. This finding is in accordance with the postulated recent transfer of O-type elements between the gene pools of D. bifasciata and S. pallida. In addition, we were able to show that the IVS3 double-spliced variants of both P element types are produced regularily in all species of the genus Drosophila investigated so far, but not in S. pallida.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00006335
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  • 9
    Electronic Resource
    Electronic Resource
    Nested insertions of short mobile sequences in Drosophila P elements (1998)
    Springer
    Chromosoma 107 (1998), S. 6-16 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. A potentially full-sized P element isolated from the genome of Drosophila ambigua by polymerase chain reaction amplification was completely sequenced. It has a length of 3329 bp and the termini are formed by 33 bp inverted repeats. Sequence comparisons show that it can be classified as a member of the T-type P element subfamily. The translational reading frames of all four exons are interrupted by stop codons and frameshift mutations. At the 3′ end of exon 3 a 687 bp insertion sequence (IS-amb-P) is found that also occurs in the form of dispersed copies (IS-amb) in the genome in D. ambigua. At the interspecific level it shows homology to mobile sequences of other species of the obscura group. Although variable in length, these IS elements are characterized by conserved sections without coding function and by 14 bp inverted repeats, one at a terminal, the other at a subterminal position. In situ hybridization revealed that P elements in D. ambigua are restricted to only two euchromatic sites on chromosome elements A and E. This situation resembles that found in Drosophila guanche and Drosophila subobscura where P homologs are clustered at a single site on chromosome element E and where the section corresponding to exon 3 of P elements carries an IS element. The gene sik-hom, which is located at the 5′ side of the D. guanche cluster of P homologs, was used as a marker to examine whether the P element sites on chromosome element E of D. guanche and D. ambigua are homologous. The results suggest that the nested insertions of IS elements into P elements must have occurred independently in the two different lineages.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004120050277
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  • 10
    Electronic Resource
    Electronic Resource
    Repetitive sequences in the genome ofAnemone blanda: Identification of tandem arrays and of dispersed repeats (1993)
    Springer
    Chromosoma 102 (1993), S. 312-324 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract A tandemly repetitive sequence family (AbS1) and a repetitive sequence (Hd) forming part of a larger dispersed element (dorf-1) ofAnemone blanda were characterised. TheAbS1 satellite sequence family is located in all 4′,6-diamidino-2-phenylindole (DAPI) positive intercalary heterochromatic bands and in the DAPI positive heterochromatic terminal region of chromosome 3, while the dispersedHd homologous sequences are preferentially associated with euchromatic chromosome regions. The major component of theAbS1 satellite isAbS1-H1 with a basic repeat unit of 1640 bp; a minor fraction (AbS1-H5) consists of 320 bp units. A subsection of theAbS1-H1 repeat unit exhibits homologies to the 25S rRNA gene of flowering plants suggesting that the 1.64 kb satellite was generated by amplification of a precursor satellite and/or single copy sequence together with an rDNA fragment. The rDNA homologous region is considered to evolve at a rate similar to pseudogenes and thus the age of this satellite DNA fraction can be roughly estimated as about 27 million years. The dispersed repeated sequenceHd (about 1300 bp) is associated with the 8 kb elementdorf-1. A. blanda dorf-1 constitutes about 0.2% of the genome (3×104 copies), is bounded by identical long terminal repeats, and exhibits partial homology to theLilium gypsy-type elementdell, but has yet to be confirmed as a retrotransposon. In contrast to theAbS1 satellite sequence family,Hd homologous sequences were found not only inA. apennina, the closest relative ofA. blanda, but also inA. nemorosa andA. ranunculoides indicating that a progenitor sequence ofdorf-1 was present in a common ancestor before speciation ocurred.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00661274
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