Mariner Elements Research Articles

Seasonal variability of crustal and marine trace elements in the aerosol at Neumayer station, Antarctica

Atmospheric trace element concentrations were measured from March 1999 to December 2003 at the Air Chemistry Observatory of the German Antarctic station Neumayer, by inductively coupled plasma–quadrupol mass spectrometry (ICP–QMS) and ion chromatography (IC). This continuous five-year long record derived from weekly aerosol sampling revealed a distinct seasonal summer maximum for elements linked with mineral dust entry (Al, La, Ce, Nd) and a winter maximum for the mostly sea salt derived elements Li, Na, K, Mg, Ca and Sr. The relative seasonal amplitude was around 1.7 and 1.4 for mineral dust (La) and sea salt aerosol (Na), respectively. On average, a significant deviation regarding mean ocean water composition was apparent for Li, Mg and Sr, which could hardly be explained by mirabilite precipitation on freshly formed sea ice. In addition, we observed all over the year, a not clarified high variability of element ratios Li/Na, K/Na, Mg/Na, Ca/Na and Sr/Na. We found an intriguing co-variation of Se concentrations with biogenic sulphur aerosols (methane sulphonate and non-sea salt sulphate), indicating a dominant marine biogenic source for this element, linked with the marine biogenic sulphur source.

Diverse Mariner-like elements in fig wasps

Mariner transposable elements are widespread and diverse in insects. We screened 10 species of fig wasps (Hymenoptera: Agaonidae) for mariner elements. All 10 species harbour a large diversity of mariner elements, most of which have interrupted reading frames in the transposase gene region, suggesting that they are inactive and ancient. We sequenced two full-length mariner elements and found evidence to suggest that they are inserted in the genome at a conserved region shared by other hymenopteran taxa. The association between mariner elements and fig wasps is old and dominated by vertical transmission, suggesting that these 'selfish genetic elements' have evolved to impart only very low costs to their hosts.

Chemical and strontium isotope characterization of rainwater in France: influence of sources and hydrogeochemical implications

Strontium isotope ratios and Ca2+, Na+, K+, Mg2+, Cl−, , and Sr2+ concentrations were measured in rainwater samples collected in four stations in France (Brest, Dax, Orleans and Clermont-Ferrand) over a period of 1 year. Each sample represented a monthly series of rain events. The chemical composition and the 87Sr/86Sr ratios of the rainwater samples varied considerably. Using Na concentrations as an indicator of marine origin, the proportion of marine and crustal elements was estimated from elemental ratios. Strontium isotopes were used to characterize the different sources using data from the four stations and the literature. Such sources include sea salts, crustal sources (carbonates, silicates and volcanic rocks) and anthropogenic sources (fertilizers, automobile exhausts, incinerators and urban heating).

Paleozoic lake faunas: Establishing aquatic life on land

Lakes are important archives for continental records of paleoenvironmental as well as paleoclimatic change. They also record a unique macroevolutionary pattern that occurred when faunas invaded the continental realm. In order to document that pattern, we compiled a database of over one hundred and six lake basins from the Neoproterozoic to Permian. Looking at this critical time in lacustrine evolution, several patterns emerge. For the Neoproterozoic through Silurian time, there is a paucity of documented lake deposits and lake faunal records. However, the records that are available indicate that lakes were oligotrophic and their nutrient cycling regimes primitive. It is not until the establishment of land plants in the Silurian that lakes began to respond with higher diversities and more complex physical and chemical conditions. During the Devonian–Carboniferous periods, diversity was on the rise as trophic structure became more complex. Most lakes of the Devonian and Carboniferous formed along continental margins or in tectonic basins with occasional connection to the marine realm. The faunas from these types of lakes were commonly comprised of mixed marine and freshwater elements and were far more diverse than other, more inland lakes. This “estuary effect” created a gateway or filter through which faunas invaded the continental realm. The early history of lake faunas is one of opportunity and amelioration. The feedback loops created by the establishment of vascular plants altered the nutrient cycle on land and in lakes. All trophic levels were established early, but became increasingly complex throughout the Paleozoic, as roles changed and faunal elements became established. Groups invading the continents via the “estuary effect” did so numerous times before establishing themselves permanently. This was linked with the episodic re-establishment in marine–freshwater connections along these continental margins.

Mobile elements and inverted rearrangements inTrimerotropis pallidipennis(Orthoptera: Acrididae)

Mobile elements are ubiquitous and extremely active agents of genome variability and evolution. They contribute the bulk of DNA in most eukaryotic genomes, and promote various chromosomal rearrangements more efficiently and often more specifically than other cellular processes (i.e. deletions, duplications and inversions). The Class II element mariner is present from fungal genomes to invertebrates and vertebrates. In this paper, the identifi- cation and chromosomal localization of a new mariner-like element is reported in the genome of Trimerotropis pal- lidipennis ,a grasshopper species with a high incidence of polymorphic inverted rearrangements with adaptive sig- nificance. This element was detected by FISH in centromeric and telomeric regions of most autosomes with pericen- tric inversions, and also in the X-chromosomes. These chromosome regions coincide in most cases with the extremes of inversions, suggesting a possible role mariner element played in the origin of inverted rearrangements in T. pallid- ipennis.

Intact mariner‐like element in tobacco budworm, Heliothis virescens (Lepidoptera: Noctuidae)

An intact mariner-like element was isolated from the genome of tobacco budworm, Heliothis virescens. This is the first report of an intact mariner element after the initial identification of Mos1 from Drosophila mauritiana. The full-length Hvmar1 has 30 bp inverted terminal repeats and a complete 1065 bp open reading frame (ORF) encoding the transposase with a 'D,D(34)D' motif in the catalytic domain. Polymerase chain reaction results show that at least one insertion of the Hvmar1 element is conserved in this Heliothis strain. Phylogenetic analysis demonstrated that Hvmar1 belongs to the irritans subfamily.

Transposable elements from the mesophragmatica group of Drosophila

Transposable elements (TEs) are middle repetitive DNA sequences classified into families according to their sequence similarities, such elements can playing an important role in the evolutionary process of their host genomes. There are many reports on the distribution of TEs in the fruit fly genus Drosophila, although there is relatively little information relating to the Neotropical mesophragmatica group of Drosophila, probably the most typical cluster of species occurring almost exclusively in the Andes mountains. Dot Blot and PCR analyses was used to study the distribution of some TEs (I, mariner, hobo, gypsy, Tom/17.6, micropia and P elements) within the mesophragmatica group of Drosophila. We found gypsy elements in all the mesophragmatica group species studied and mariner elements were absent only from Drosophila pavani but P element homologous sequences were present only in D. pavani and Drosophila gasici and the other TEs (I, hobo, Tom/17.6, micropia) were not found in any of the species investigated.

Paleobiogeography and Evolutionary History of Paleozoic Lacustrine Faunas

Lakes are important archives for continental records of paleoenvironmental as well as paleoclimatic change. They also record a unique macroevolutionary pattern that occurred when faunas invaded the continental realm. In order to document that pattern, we compiled a database of over ninety lake basins from the Neoproterozoic to the Permian. Each basin was evaluated based upon its sedimentology and paleontology and, where appropriate, was classified into one of three types: underfilled, balanced-filled, and overfilled, sensu Carroll and Bohacs (1999). The faunal elements from each were recorded at the species, generic, class, and phylum levels.Looking at this critical time in lacustrine evolution, several patterns emerged. For the Neoproterozoic through Silurian time, there is a paucity of documented lake deposits and lake faunal records. Lakes during this time were oligotrophic and their nutrient cycling regimes were primitive. It is not until the establishment of land plants in the Silurian that lakes begin to respond with higher diversities and more complex physical and chemical conditions. During the Devonian-Carboniferous periods, diversity was on the rise as trophic levels became more complex. Globally, CO2 increased while marine Sr decreased, coinciding with the peaking of diversity within lakes. Most lakes of the Devonian and Carboniferous formed along continental margins or in tectonic basins with occasional connection to the marine realm. The faunas from these types of lakes were commonly comprised of mixed marine and freshwater elements and were far more diverse than other, more inland lakes. This “estuary effect” created a gateway or filter through which faunas invaded the continental realm.The early history of lake faunas is one of opportunity and amelioration. The feedback loops created by the establishment of vascular plants altered the nutrient cycle on land and in lakes. All trophic levels were established early but became increasingly complex throughout the Paleozoic, as roles changed and faunal elements became established. Groups invading the continents via the “estuary effect” did so numerous times before establishing themselves permanently. This was linked with the episodic reestablishment in marine-freshwater connections along these continental margins. In general, the macroevolutionary history of lake faunas demonstrates a dramatically different diversification pattern than that of the marine, and further study is necessary to understand the intricacies of these patterns and whether or not they continue through the Mesozoic and Cenozoic eras.

Size Distribution of Trace Elements and Major Ions in the Eastern Mediterranean Atmosphere

Size distribution of trace elements is measured at the Mediterranean coast of Turkey, by analyzing hi-vol impactor samples collected between August 1993 and May 1994. Mass median diameters of marine elements are between 4.6 and 5.3 μm, and those of crustal elements are between 3.0 and 3.5 μm. Mass median diameters of crustal elements are 30% smaller in samples impacted by Saharan Dust. Pollution derived elements, As, Cd, Mo, Pb, Se, and Zn have MMD's between 1.25 and 1.01 μm. Although 70–90% of the masses of these elements were associated with particles smaller than 2.1 μm, 10–30% of their mass was associated with coarse particles. Coarse component in concentrations of Cd, Pb, Sb and particulate Hg are due to adsorption of fine anthropogenic particles on coarse crustal aerosol, whereas coarse fraction Zn, As, Se, In, Mo and Au are crustal at Al concentrations > 100 ng m−3. Bromine, Cr, Ni, and V have bimodal distributions. The fine component, which account for approximately 30–40% of their masses are due to anthropogenic sources, whereas the coarse component, which accounts for 30–50% of their masses are due to sea salt for Br, and crustal particles for Cr, Ni, and V.

Dry and wet deposition of elements in Hong Kong

Inductively coupled plasma-mass spectrometry (ICP-MS) was used to characterize fourteen major and trace elements including Al, Fe, Na, K, Mg, Ti, Ba, Cu, Mn, Pb, Sb, Sr, V, and Zn, in dry and wet deposition samples collected in Hong Kong. Calculated model deposition velocities for various elements showed that marine elements such as Na, Mg, and Sr exhibited the highest deposition velocities (from 1.0 cm s − 1 to 1.2 cm s − 1), while pollution elements including V, Sb, and Pb had the lowest deposition velocities (0.2 cm s − 1). The positive correlation of deposition velocities between crustal and marine elements suggests that the deposition velocities were influenced by the particle size in addition to other factors such as wind speed and humidity. A comparison between modeled dry fluxes (the indirect method) and measured dry fluxes (the direct method) showed that modeled dry fluxes were slightly higher for marine and crustal elements while measured dry fluxes were higher for the pollution elements. Comparisons of measured dry and wet deposition fluxes for various elements in Hong Kong indicated that dry and wet removal processes were of similar significance for crustal and marine elements. However, wet removal was dominant for the pollution elements (93% V, 86% K, 81% Sb, and 75% Pb).

Molecular characterization ofVulmar1, a completemarinertransposon of sugar beet and diversity ofmariner- andEn/Spm-like sequences in the genusBeta

Transposons of the Tc1-mariner superfamily are widespread in eukaryotic genomes. We have isolated the mariner element Vulmar1 from Beta vulgaris L., which is 3909 bp long and bordered by perfect terminal inverted repeats of 32 bp with homology to terminal inverted repeats of transposons from soybean and rice. According to a characteristic amino acid signature, Vulmar1 can be assigned to the DD39D group of mariner transposons. Vulmar1 is flanked by a 5'-TA-3' target site duplication that is typical for mariner transposons. Southern hybridization revealed that mariner-like copies are highly abundant in Beta species, and sequence analysis of 10 transposase fragments from representative species of the four Beta sections revealed an identity between 34% and 100% after conceptual translation. By fluorescent in situ hybridization, Vulmar1 was detected in distal euchromatin as well as in some intercalary and pericentromeric regions of all B. vulgaris chromosomes. In addition, using PCR, we were able to amplify fragments of the transposase gene of En/Spm-like transposons in the genus Beta. En/Spm-like transposase sequences are highly amplified in four Beta sections and showed a considerable degree of conservation (88.5-100%) at the protein level, while the homology to corresponding regions of En/Spm transposons of other plant species ranges from 49.5% to 62.5%. By fluorescent in situ hybridization, En/Spm-like transposon signals of strong intensity were detected on all chromosomes of B. vulgaris.

Palynology and palaeovegetation reconstruction in late Quaternary sediments of the southern Suez Isthmus, Egypt

Palynomorphs from two boreholes (26 and 20 m depths) have been used to document the palaeovegetation, palaeoenvironmental and palaeoclimatic interpretations during the late Quaternary of the southern Suez Isthmus. The palynological assemblages are characterized by dominance of terrestrial palynomorphs as well as common marine elements that are used to construct the eustatic sea level fluctuations. The sea level stands were low at the lower part and increased gradually to reach a high stand at the upper part of the section. Fresh water deltaic or lagoonal-marshy environments prevailed during the accumulation of the studied deposits as a result of the Nile flooding, and rainfall which was recorded on the northern Red Sea region at that time. Pollen spectra indicate that when the steppe pollen was extensive, the climate was dry and probably cool. On the other hand, tree forest was abundant as the climate became warm and more humid. The steppe and tree pollen are similar or nearly equal in proportions when the climate was intermediate (mild) between arid and humid periods.

Cryptospore Assemblages from the Ordovician/silurian Boundary in the Puna Region, North‐west Argentina

Palynomorph assemblages have been recovered from deposits believed to straddle the Ordovician/Silurian boundary, from the upper member of the Salar del Rincón Formation, in the Puna region of north‐west Argentina. The palynomorph assemblages are dominated by terrestrial cryptospores, but also contain marine elements (acritarchs, prasinophycean algae and chitinozoans). The cryptospore assemblages are similar in composition to those described from coeval deposits worldwide, suggesting that the producers were cosmopolitan and tolerated a wide range of climatic conditions. They are correlated with the Imperfectotriletes spp. Interval Biozone (sub‐biozone α) of the Imperfectotriletes spp.‐Laevolancis divellomedia Assemblage Biozone, indicating a Hirnantian (latest Ordovician) age. Acritarchs include late Ordovician species such as Eupoikilosusa striata and Villosacapsula cf. setosapellicula, that coexist with the Llandovery species Dactylofusa estillis. Based on lithological and palynological evidence, an early Llandovery, or a late Hirnantian (post‐glacial) age is proposed for the basal part of the upper member of the Salar del Rincón Formation.

Mapping of a Leishmania major gene/locus that confers pentamidine resistance by deletion and insertion of transposable element.

Pentamidine (PEN) is an alternative compound to treat antimony-resistant leishmaniasis patients, which cellular target remains unclear. One approach to the identification of prospective targets is to identify genes able to mediate PEN resistance following overexpression. Starting from a genomic library of transfected parasites bearing a multicopy episomal cosmid vector containing wild-type Leishmania major DNA, we isolated one locus capable to render PEN resistance to wild type cells after DNA transfection. In order to map this Leishmania locus, cosmid insert was deleted by two successive sets of partial digestion with restriction enzymes, followed by transfection into wild type cells, overexpression, induction and functional tests in the presence of PEN. To determine the Leishmania gene related to PEN resistance, nucleotide sequencing experiments were done through insertion of the transposon Mariner element of Drosophila melanogaster (mosK) into the deleted insert to work as primer island. Using general molecular techniques, we described here this method that permits a quickly identification of a functional gene facilitating nucleotide sequence experiments from large DNA fragments. Followed experiments revealed the presence of a P-Glycoprotein gene in this locus which role in Leishmania metabolism has now been analyzed.

Identification of two mariner-like elements in the genome of the mosquito Ochlerotatus atropalpus

Two distinct mariner-like elements, Atmar-1 and Atmar-2, were isolated from the genome of the mosquito Ochlerotatus atropalpus. Full-sized Atmar-1 elements, obtained by screening a genomic library, have a 1293-bp consensus sequence with 27-bp inverted terminal repeats and a 1047-bp open reading frame (ORF) encoding the transposase. The Atmar-2 elements were amplified by polymerase chain reaction from genomic DNA and contain the central part of the transposase ORF. Individual clones of both mariner elements contain deletions, frameshifts, and stop codons. The Atmar-1 elements are present in 370–1200 copies, while the Atmar-2 elements are present in approximately 100–300 copies per haploid genome. One of the Atmar-1 elements, Atmar-1.33, could be mobilized, suggesting the presence of functional Atmar-1 elements elsewhere in the genome. Phylogenetic analysis demonstrated that Atmar-1 elements belong to the irritans subfamily and Atmar-2 elements to the cecropia subfamily of mariner elements.

Late Cretaceous vertebrates from bajo de Santa Rosa (Allen Formation), Río Negro province, Argentina, with the description of a new sauropod dinosaur (Titanosauridae)

A large and diverse collection of vertebrate remains from the Campanian-Maastrichtian Allen Formation (Malargue Group) at the Bajo deSanta Rosalocality (Rio Negro Province,Argentina) is described here. The vertebrates are represented by: chondrichthyans; diplomystid siluriform, lepisosteid, cf. percichthyid and dipnoid osteichthyans; pipid and leptodactylid anurans; chelid turthes; sphenodonts; elasmosaurid plesiosaurs; madtsoiid snakes; faveoolitid and megaloolithid eggshells; and hadrosaurid, cf. carcharodontosaurid and titanosaurid dinosaurs. A new small saltasaurine titanosaurid, Bonatitan reigi gen. et sp. nov., is described. It is diagnosed by the following association of characters: 1) longitudinal groove located on the suture between parietals that continues posteriorly over the supraoccipital to the foramen magnum; 2) basisphenoid tubera long and narrow (more than twice as long as wide); 3) dorsal to middle caudal vertebrae with deep oval to circular pits present on both sides of the prespinal lamina; 4) anterior caudal vertebra with spino-postzygapophysial and spino-prezygapophysial laminae; 5) neural arch of anterior caudals with deep interzygapophysial fossae with numerous pits; 6) anterior caudal vertebra with an accessory sub-horizontal lamina extending from the antero-ventral portion of the postzygapophysis to the mid-portion of the spino-prezygapophysial lamina; and finally, 7) anterior caudal vertebra with a prominent axial crest on the ventral surface of the cemtrum. The first record of sphenodonts and cf. carcharodontosaurid theropods is recognized for the upper Late Cretaceous of Patagonia, as well as the earliest record of percichthyids (Perciformes). The vertebrate record is mainly composed of terrestrial and freshwater taxa, but a few marine elements are found (elasmosaurids) indicating a marine influence during the deposition of the Allen Formation in the area of Bajo deSanta Rosa. The vertebrate remains support a Campanian-Maastrichtian age for the Allen Formation. Comparisons with other South American Campanian-Maastrichtian localities suggest a similar fossil vertebrate composition, with relatively few differences between the Patagonian and extra Patagonian South American records. Key words: Late Cretaceous, osteichthyans, chondrichthyans, anurans, turtles, sphenodonts, plesiosaurs, ophidians, dinosaurs,Patagonia.

In vitro shuttle mutagenesis using engineered mariner transposons.

Advances in our understanding of the protozoan parasite Leishmania have been facilitated by the development of molecular and genetic tools. One powerful approach for gene identification and analysis is transposon mutagenesis. This can be performed directly in vivo, but often it is more convenient to generate transpositions in vitro for subsequent analysis in vivo, in a process termed "shuttle mutagenesis." The Drosophila element mariner is well suited for application by either route. Minimal mariner elements containing cis-acting elements required for transposition have been generated, which can be further modified to suit the needs of the experimenter. Additional genetic markers and/or reporters can be introduced, which are useful for procedures such as insertional mutagenesis, shotgun sequencing, or the generation of protein and transcriptional fusions for subsequent analysis. Active transposase can readily be generated following expression in Escherichia coli, and efficiencies of 10-3/target can be obtained, allow-ing the generation of large transposon insertion libraries suitable for subsequent screening in vivo. This chapter explains the steps necessary to purify active Mos1 transposase and conduct an in vitro transposition reaction. We also discuss some of the considerations relevant to the design and application of functional mariner elements (donor plasmids) relevant to studies in Leishmania and other organisms.

Post-integration behavior of a Mos1 mariner gene vector in Aedes aegypti

The post-integration behavior of insect gene vectors will determine the types of applications for which they can be used. Transposon mutagenesis, enhancer trapping, and the use of transposable elements as genetic drive systems in insects requires transposable elements with high rates of remobilization in the presence of transposase. We investigated the post-integration behavior of the Mos1 mariner element in transgenic Aedes aegypti by examining both germ-line and somatic transpositions of a non-autonomous element in the presence of Mos1 transposase. Somatic transpositions were occasionally detected while germ-line transposition was only rarely observed. Only a single germ-line transposition event was recovered after screening 14,000 progeny. The observed patterns of transposition suggest that Mos1 movement takes place between the S phase and anaphase. The data reported here indicate that Mos1 will be a useful vector in Ae. aegypti for applications requiring a very high degree of vector stability but will have limited use in the construction of genetic drive, enhancer trap, or transposon tagging systems in this species.

Target sequences of Tc1, Tc3 and Tc5 transposons of Caenorhabditis elegans.

We report here the consensus target sequence of transposons Tc1, Tc3 and Tc5 of Caenorhabditis elegans. These sequences were obtained by molecular analysis of 1008 random new insertions which have not been exposed to natural selection. This analysis reveals consensus target sites slightly different from those previously reported, and confirms that the mariner elements Tc1 and Tc3 insert in sites which are not preferentially palindromic.

Parasitism at the ecosystem level in the Baltic Sea.

The Baltic Sea is characterized by organisms that can tolerate brackish water. Because of the Sea's history during glacial times, its flora and fauna (and also their parasites) can be traced to marine, freshwater and genuine brackish elements beside glacial relics. Snails, planktonic copepods, benthic amphipods and isopods are important intermediate hosts of diverse helminths; in addition polychaetes, bivalves and fishes may also act as final hosts. The most important final hosts, beside fishes, were seals and birds; these were able to disperse the parasites over the whole of the Baltic. Decreasing salinity from west to east limits the distribution of many parasites. Several marine and genuine brackish water species have almost spread over the whole Baltic. Freshwater species, however, have a lower tolerance than marine species and are only rarely found in the western part. A serious problem in the Baltic is eutrophication which can lead to massive abundances of generalist parasites, in host populations as well as host individuals. The final stage of this influence can cause a general decrease of host abundance and, as a consequence, of all kinds of parasites, due to oxygen deficiency. In comparison with the species spectrum of other brackish waters in Europe, the Baltic presents some endemic parasites as well as sharing parasite species with the Mediterranean and even the Black Sea.