Litiumin dispersio Rapasaaren spodumeenipegmatiittien sivukivessä Keski-Pohjanmaalla

Tiivistelmä. Työssä tutkittiin litiumin dispersiota Keski-Pohjanmaan Kaustisen litiumprovinssiin kuuluvan Rapasaaren spodumeenipegmatiittiesiintymän sivukivissä. Spodumeeni-pegmatiitit synnyttävät ympärilleen volatiileista alkuaineista, kuten litiumista, rikastuneen dispersiokehän, jolloin ne muuttavat isäntäkiviään metasomaattisesti. Dispersiokehä havaitaan sivukiven taustapitoisuutta korkeampina litiumpitoisuuksina. Litiumpitoisuus sivukivessä on käänteisesti verrannollinen etäisyyteen pegmatiittijuonesta. Työn tarkoituksena oli selvittää tutkimusalueen litiumin taustapitoisuus suprakrustisissa kivissä ja arvioida pegmatiitista sivukiveen siirtyneen litiumin määrää. Tutkimusaineisto kerättiin Rapasaaren esiintymän kairasydännäytteistä, ja näytteiden etäisyys pegmatiitista saatiin kairasydänraporteista. Näytteet analysoitiin käyttäen ICP-OES-menetelmää. Litiumpitoisuudet esitettiin etäisyyden funktiona pegmatiitista ja saatua jakaumaa mallinnettiin diffuusiota kuvaavalla virhefunktion komplementin kaavalla. Kaavat sovitettiin tuloksiin ja siten kyettiin arvioimaan dispersioon kuluneen ajan ja diffuusiokertoimen suhdetta. Dispersiokehän muodostanutta fluidin pitoisuutta mallinnettiin pegmatiittijuonten sivukiven kontaktin näytteiden pitoisuuksien avulla. Työn tulokset viittaavat Rapasaaren esiintymän reunaosien litiumista köyhtyneiden pegmatiittijuonien initiaalisiksi pitoisuuksiksi noin 5000–8000 ppm Li, joka vastaa mallinnettua fluidin pitoisuutta. Esiintymän pegmatiiteista voidaan tulosten perusteella arvioida siirtyneen litiumia sivukiveen keskimäärin 10–15 %, vaikkakin joissakin yksittäisissä pegmatiittijuonissa lähes kaikki litium on siirtynyt sivukiveen. Lisäksi voidaan todeta dispersiokehän muodostuneen varsin nopeasti pegmatiittijuonen synnyn jälkeen diffuusiokertoimen ja ajan tarkastelun perusteella

Seuruututkimus Turkuun muuttaneen oululaisen yksilömurteen kehityksestä

Tiivistelmä. Kandidaatintutkielmani on seuruututkimus yhden yksilömurteen eli idiolektin kehityksestä. Informanttini on syntynyt Oulussa vuonna 1994 ja asunut kaupungissa aikuisikäänsä saakka. Hän muutti 23-vuotiaana uudelle murrealueelle Turkuun. Aloitin informanttini puheen tallentamisen kolme kuukautta myöhemmin hänen muutostaan joulukuussa 2017 ja jatkoin nauhoituksien ottamista vajaan puolen vuoden välein aina huhtikuuhun 2019 saakka. Tässä kandidaatintutkielmassa tarkastelen informanttini puheesta valikoitujen kielenpiirteiden muuttumista ja variaatiota. Olen valinnut tutkittaviksi piirteiksi inessiivin, yleisgeminaation sekä persoonapronominit niiden esiintymismäärän ja kiinnostavuuden perusteella. Tutkimustulosteni perusteella informanttini on yleiskielistynyt muutettuaan uudelle murrealueelle. Murteelliset variantit ovat joko vähentyneet merkittävästi tai jopa karsiutuneet kokonaan pois ja korvautuneet yleiskielisillä varianteilla

Genome Sequence of the Endosymbiont Rickettsia peacockii and Comparison with Virulent Rickettsia rickettsii: Identification of Virulence Factors

Rickettsia peacockii, also known as the East Side Agent, is a non-pathogenic obligate intracellular bacterium found as an endosymbiont in Dermacentor andersoni ticks in the western USA and Canada. Its presence in ticks is correlated with reduced prevalence of Rickettsia rickettsii, the agent of Rocky Mountain Spotted Fever. It has been proposed that a virulent SFG rickettsia underwent changes to become the East Side Agent. We determined the genome sequence of R. peacockii and provide a comparison to a closely related virulent R. rickettsii. The presence of 42 chromosomal copies of the ISRpe1 transposon in the genome of R. peacockii is associated with a lack of synteny with the genome of R. rickettsii and numerous deletions via recombination between transposon copies. The plasmid contains a number of genes from distantly related organisms, such as part of the glycosylation island of Pseudomonas aeruginosa. Genes deleted or mutated in R. peacockii which may relate to loss of virulence include those coding for an ankyrin repeat containing protein, DsbA, RickA, protease II, OmpA, ScaI, and a putative phosphoethanolamine transferase. The gene coding for the ankyrin repeat containing protein is especially implicated as it is mutated in R. rickettsii strain Iowa, which has attenuated virulence. Presence of numerous copies of the ISRpe1 transposon, likely acquired by lateral transfer from a Cardinium species, are associated with extensive genomic reorganization and deletions. The deletion and mutation of genes possibly involved in loss of virulence have been identified by this genomic comparison. It also illustrates that the introduction of a transposon into the genome can have varied effects; either correlating with an increase in pathogenicity as in Francisella tularensis or a loss of pathogenicity as in R. peacockii and the recombination enabled by multiple transposon copies can cause significant deletions in some genomes while not in others

Rickettsial ompB Promoter Regulated Expression of GFPuv in Transformed Rickettsia montanensis

Background: Rickettsia spp. (Rickettsiales: Rickettsiaceae) are Gram-negative, obligate intracellular, a-proteobacteria that have historically been associated with blood-feeding arthropods. Certain species cause typhus and spotted fevers in humans, but others are of uncertain pathogenicity or may be strict arthropod endosymbionts. Genetic manipulation of rickettsiae should facilitate a better understanding of their interactions with hosts. Methodology/Principal Findings: We transformed a species never associated with human disease, Rickettsia montanensis, by electroporation with a TN5 transposon (pMOD700) containing green fluorescent protein (GFPuv) and chloramphenicol acetyltransferase (CAT) genes under regulation of promoters cloned from the Rickettsia rickettsii ompB gene, and isolated a Chloramphenicol-resistant GFP-fluorescent rickettsiae population (Rmontanensis700). The Rmontanensis700 rickettsiae contained a single transposon integrated near an acetyl-CoA acetyltransferase gene in the rickettsial chromosome. Northern blots showed that GFPuv and CAT mRNAs were both expressed as two transcripts of larger and smaller than predicted length. Western immunoblots showed that Rmontanensis700 and E. coli transformed with a plasmid containing the pMOD700 transposon both expressed GFPuv proteins of the predicted molecular weight. Conclusions/Significance: Long-standing barriers to transformation of rickettsiae have been overcome by development of transposon-based rickettsial transformation vectors. The ompB promoter may be the most problematic of the fou

Gene silencing in tick cell lines using small interfering or long double-stranded RNA

Gene silencing by RNA interference (RNAi) is an important research tool in many areas of biology. To effectively harness the power of this technique in order to explore tick functional genomics and tick-microorganism interactions, optimised parameters for RNAi-mediated gene silencing in tick cells need to be established. Ten cell lines from four economically important ixodid tick genera (Amblyomma, Hyalomma, Ixodes and Rhipicephalus including the sub-species Boophilus) were used to examine key parameters including small interfering RNA (siRNA), double stranded RNA (dsRNA), transfection reagent and incubation time for silencing virus reporter and endogenous tick genes. Transfection reagents were essential for the uptake of siRNA whereas long dsRNA alone was taken up by most tick cell lines. Significant virus reporter protein knockdown was achieved using either siRNA or dsRNA in all the cell lines tested. Optimum conditions varied according to the cell line. Consistency between replicates and duration of incubation with dsRNA were addressed for two Ixodes scapularis cell lines; IDE8 supported more consistent and effective silencing of the endogenous gene subolesin than ISE6, and highly significant knockdown of the endogenous gene 2I1F6 in IDE8 cells was achieved within 48 h incubation with dsRNA. In summary, this study shows that gene silencing by RNAi in tick cell lines is generally more efficient with dsRNA than with siRNA but results vary between cell lines and optimal parameters need to be determined for each experimental system

Transcriptome Responses of Insect Fat Body Cells to Tissue Culture Environment

Tissue culture is performed to maintain isolated portions of multicellular organisms in an artificial milieu that is outside the individual organism and for considerable periods of time; cells derived from cultured explants are, in general, different from cells of the corresponding tissue in a living organism. The changes in cultured tissues that precede and often explain the subsequent cell proliferation of explant-derived cells have been partially studied, but little is known about the molecular and genomic basis of these changes. Comparative transcriptomics of intact and cultured (90 hours in MGM-450 insect medium) Bombyx mori tissues revealed that fewer genes represented a larger portion of the transcriptome of intact fat body tissues than of cultured fat body tissues. This analysis also indicated that expression of genes encoding sugar transporters and immune response proteins increased during culture and that expression of genes encoding lipoproteins and cuticle proteins decreased during culture. These results provide support for hypotheses that cultured tissues respond immunologically to surgery, adapt to the medium by accelerating sugar uptake, and terminate their identity as part of an intact organism by becoming independent of that organism

Development of Shuttle Vectors for Transformation of Diverse Rickettsia Species

Plasmids have been identified in most species of Rickettsia examined, with some species maintaining multiple different plasmids. Three distinct plasmids were demonstrated in Rickettsia amblyommii AaR/SC by Southern analysis using plasmid specific probes. Copy numbers of pRAM18, pRAM23 and pRAM32 per chromosome in AaR/SC were estimated by real-time PCR to be 2.0, 1.9 and 1.3 respectively. Cloning and sequencing of R. amblyommii AaR/SC plasmids provided an opportunity to develop shuttle vectors for transformation of rickettsiae. A selection cassette encoding rifampin resistance and a fluorescent marker was inserted into pRAM18 yielding a 27.6 kbp recombinant plasmid, pRAM18/Rif/GFPuv. Electroporation of Rickettsia parkeri and Rickettsia bellii with pRAM18/Rif/GFPuv yielded GFPuv-expressing rickettsiae within 2 weeks. Smaller vectors, pRAM18dRG, pRAM18dRGA and pRAM32dRGA each bearing the same selection cassette, were made by moving the parA and dnaA-like genes from pRAM18 or pRAM32 into a vector backbone. R. bellii maintained the highest numbers of pRAM18dRGA (13.3 – 28.1 copies), and R. parkeri, Rickettsia monacensis and Rickettsia montanensis contained 9.9, 5.5 and 7.5 copies respectively. The same species transformed with pRAM32dRGA maintained 2.6, 2.5, 3.2 and 3.6 copies. pRM, the plasmid native to R. monacensis, was still present in shuttle vector transformed R. monacensis at a level similar to that found in wild type R. monacensis after 15 subcultures. Stable transformation of diverse rickettsiae was achieved with a shuttle vector system based on R. amblyommii plasmids pRAM18 and pRAM32, providing a new research tool that will greatly facilitate genetic and biological studies of rickettsiae

A Novel Obligate Intracellular Gamma-Proteobacterium Associated with Ixodid Ticks, Diplorickettsia massiliensis, Gen. Nov., Sp. Nov

Background: Obligate intracellular bacteria of arthropods often exhibit a significant role in either human health or arthropod ecology. Methodology/Principal Findings: An obligate intracellular gamma-proteobacterium was isolated from the actively questing hard tick Ixodes ricinus using mammalian and amphibian cell lines. Transmission electron microscopy revealed a unique morphology of the bacterium, including intravacuolar localization of bacteria grouped predominantly in pairs and internal structures composed of electron-dense crystal-like structures and regular multilayer sheath-like structures. The isolate 20B was characterized to determine its taxonomic position using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that this strain belongs to the family Coxiellaceae, order Legionellales of Gamma-proteobacteria, and the closest relatives are different Rickettsiella spp. The level of 16S rRNA gene sequence similarity between strain 20B and other recognized species of the family was below 94.5%. Partial sequences of the rpoB, parC and ftsY genes confirmed the phylogenetic position of the new isolate. The G+C content estimated on the basis of whole genome analysis of strain 20B was 37.88%. On the basis of its phenotypic and genotypic properties, together with phylogenetic distinctiveness, we propose that strain 20B to be classified in the new genus Diplorickettsia as the type strain of a novel species named Diplorickettsia massiliensis sp. nov. Conclusions/Significance: Considering the source of its isolation (hard tick, often biting humans) the role of this bacterium in the pathology of humans, animals and ticks should be further investigated

No Evidence for Immune Priming in Ants Exposed to a Fungal Pathogen

There is accumulating evidence that invertebrates can acquire long-term protection against pathogens through immune priming. However, the range of pathogens eliciting immune priming and the specificity of the response remain unclear. Here, we tested if the exposure to a natural fungal pathogen elicited immune priming in ants. We found no evidence for immune priming in Formica selysi workers exposed to Beauveria bassiana. The initial exposure of ants to the fungus did not alter their resistance in a subsequent challenge with the same fungus. There was no sign of priming when using homologous and heterologous combinations of fungal strains for exposure and subsequent challenges at two time intervals. Hence, within the range of conditions tested, the immune response of this social insect to the fungal pathogen appears to lack memory and strain-specificity. These results show that immune priming is not ubiquitous across pathogens, hosts and conditions, possibly because of immune evasion by the pathogen or efficient social defences by the host