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| 2. |
- Andersson, Björn, et al.
(författare)
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Complete sequence of a 93.4 kb contig from chromosome 3 of Trypanosoma cruzi containing a strand switch region
- 1998
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Ingår i: Genome Research. - : Cold Spring Harbor Laboratory. - 1088-9051 .- 1549-5469. ; 8:8, s. 809-816
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Tidskriftsartikel (refereegranskat)abstract
- We have initiated large-scale sequencing of the third smallest chromosome of the CL Brener strain of Trypanosoma cruzi and we report here the complete sequence of a contig consisting of three cosmids. This contig covers 93.4 kb and has been found to contain 20-30 novel genes and several repeat elements, including a novel chromosome 3-specific 400-bp repeat sequence. The intergenic sequences were found to be rich in di- and trinucleotide repeats of varying lengths and also contained several known T. cruzi repeat elements. The sequence contains 29 open reading frames (ORFs) longer than 700 bp, the longest being 5157 bp, and a large number of shorter ORFs. Of the long ORFs, seven show homology to known genes in parasites and other organisms, whereas four ORFs were confirmed by sequencing of cDNA clones. Two shorter ORFs were confirmed by a database homology and a cDNA clone, respectively, and one RNA gene was identified. The identified genes include two copies of the gene for alanine-aminotransferase as well as genes for glucose-6-phosphate isomerase, protein kinases and phosphatases, and an ATP synthase subunit. An interesting feature of the sequence was that the genes appear to be organized in two long clusters containing multiple genes on the same strand. The two clusters are transcribed in opposite directions and they are separated by an approximately 20-kb long, relatively GC-rich sequence, that contains two large repetitive elements as well as a pseudogene for cruzipain and a gene for U2snRNA. It is likely that this strand switch region contains one or more regulatory and promoter regions. The reported sequence provides the first insight into the genome organization of T. cruzi and shows the potential of this approach for rapid identification of novel genes. [The sequence data described in this paper have been submitted to the GenBank data library under accession nos. AF052831-AF052833.]
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| 4. |
- Ferella, Marcela, et al.
(författare)
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A solanesyl-diphosphate synthase localizes in glycosomes of Trypanosoma cruzi
- 2006
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 281:51, s. 39339-39348
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Tidskriftsartikel (refereegranskat)abstract
- We report the cloning of a Trypanosoma cruzi gene encoding a solanesyl-diphosphate synthase, TcSPPS. The amino acid sequence ( molecular mass similar to 39 kDa) is homologous to polyprenyl-diphosphate synthases from different organisms, showing the seven conserved motifs and the typical hydrophobic profile. TcSPPS preferred geranylgeranyl diphosphate as the allylic substrate. The final product, as determined by TLC, had nine isoprene units. This suggests that the parasite synthesizes mainly ubiquinone-9 (UQ-9), as described for Trypanosoma brucei and Leishmania major. In fact, that was the length of the ubiquinone extracted from epimastigotes, as determined by high-performance liquid chromatography. Expression of TcSPPS was able to complement an Escherichia coli ispB mutant. A punctuated pattern in the cytoplasm of the parasite was detected by immunofluorescence analysis with a specific polyclonal antibody against TcSPPS. An overlapping fluorescence pattern was observed using an antibody directed against the glycosomal marker pyruvate phosphate dikinase, suggesting that this step of the isoprenoid biosynthetic pathway is located in the glycosomes. Co-localization in glycosomes was confirmed by immunogold electron microscopy and subcellular fractionation. Because UQ has a central role in energy production and in reoxidation of reduction equivalents, TcSPPS is promising as a new chemotherapeutic target.
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| 5. |
- Franzen, Oscar, et al.
(författare)
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The Short Non-Coding Transcriptome of the Protozoan Parasite Trypanosoma cruzi
- 2011
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Ingår i: PLoS Neglected Tropical Diseases. - : Public Library of Science (PLoS). - 1935-2727 .- 1935-2735. ; 5:8, s. e1283-
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Tidskriftsartikel (refereegranskat)abstract
- The pathway for RNA interference is widespread in metazoans and participates in numerous cellular tasks, from gene silencing to chromatin remodeling and protection against retrotransposition. The unicellular eukaryote Trypanosoma cruzi is missing the canonical RNAi pathway and is unable to induce RNAi-related processes. To further understand alternative RNA pathways operating in this organism, we have performed deep sequencing and genome-wide analyses of a size-fractioned cDNA library (16-61 nt) from the epimastigote life stage. Deep sequencing generated 582,243 short sequences of which 91% could be aligned with the genome sequence. About 95-98% of the aligned data (depending on the haplotype) corresponded to small RNAs derived from tRNAs, rRNAs, snRNAs and snoRNAs. The largest class consisted of tRNA-derived small RNAs which primarily originated from the 3' end of tRNAs, followed by small RNAs derived from rRNA. The remaining sequences revealed the presence of 92 novel transcribed loci, of which 79 did not show homology to known RNA classes.
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| 6. |
- Hanke, J, et al.
(författare)
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Mapping the Trypanosoma cruzi genome : Analyses of representative cosmid libraries
- 1996
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Ingår i: BioTechniques. - 0736-6205 .- 1940-9818. ; 21:4, s. 686-688
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Tidskriftsartikel (refereegranskat)abstract
- In order to generate contiguous cosmid coverage of the genome of the protozoan parasite Trypanosoma cruzi for large-scale sequence analysis, a cosmid library of 36864 individual, primary clones was generated. Total genomic DNA of the reference strain CL Brener was fragmented both by partial digestion with MboI and by physical shearing. For cloning, a modified cosmid vector was used that simplifies analyses such as restriction mapping. The library's representation is about 25 genome equivalents, assuming a size of 55 Mb per haploid genome. No chimerism of inserts in the clones could be detected. The colinearity between cosmid inserts and genomic DNA was verified. Also, hybridizations to the gel-separated karyotype of the organism were carried out as a quality check. Gridded onto two nylon filters, the library was analyzed with a variety of probes. Apart from being used for combined physical and transcriptional mapping of the genome, library filters and clones are also available to interested parties.
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| 7. |
- Henriksson, Jan, et al.
(författare)
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Karyotype variability in Trypanosoma cruzi
- 1996
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Ingår i: Parasitology Today. - : Elsevier BV. - 0169-4758 .- 1873-1473. ; 12:3, s. 108-114
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Tidskriftsartikel (refereegranskat)abstract
- Like many other protozoam parasites, Trypanosoma cruzi (the causative agent of Chagas disease) has a plastic genome. Chromosome size polymorphisms occur in different strains of T. cruzi as well as among clones originating from the same strain, Despite this polymorphism, major interchromosomal rearrangements appear to be rare since several linkage groups of chromosomal markers are well conserved among different T. cruzi strains. In addition, some correlation has been found between karyotype variability and classification by multilocus enzyme electrophoresis. In this review, Jan Henriksson, Lena Åslund and Ulf Petterson discuss the genomic variability and suggest that amplication of repetitive sequences or members of gene families make a major contribution to the chromosomal size variation
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| 8. |
- Hensvik, Lena, 1981-
(författare)
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The effects of markets, managers and peers on worker outcomes
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Essay 1: This essay exploits the entry of private independent high schools in Sweden to examine how local school competition affects the wages and the mobility of teachers in a market with individual wage bargaining. Using rich matched employer-employee panel data covering all high school teachers over a period of 16 years, I show that the entry of private schools is associated with higher teacher salaries, including higher salaries for teachers in public schools. The wage returns from competition are highest for teachers entering the profession and for teachers trained in math and science. Private school entry has also increased wage dispersion between high- and low-skilled teachers within the same field. Several robustness checks support a causal interpretation of the results, which draw attention to the potential effects of school competition on teacher supply, through the more differentiated wage setting of teachers. Essay 2: (with Olof Åslund and Oskar Nordström Skans) We investigate how manager origin affects hiring patterns, job separations, and entry wages. The analysis, draws on a longitudinal matched employer-employee data including more than 100,000 workplaces during a nine year period. Immigrant managers are substantially more likely to hire immigrants, a result robust to comparisons within 5-digit industry and location as well as within firms across establishments. The finding holds also when we follow establishments that change management over time, even accounting for trends. Origin dissimilarity increases separations within the first year of employment, but there is no impact on entry wages. Several results point to information asymmetries as an important explanation to the patterns. Essay 3: The third essay examines whether women benefit from working under female management. I use matched employer-employee panel data for Sweden, which enables me to account for unobserved heterogeneity among both workers and firms. In line with existing work, I document a substantial negative correlation between the proportion of female managers and the establishment’s gender wage gap. However, most of this relationship reflects worker heterogeneity, suggesting that sorting is an important explanation for the lower gender wage difference in female-led firms. Further analysis supports this conclusion by showing that while female managers are not more likely to hire same-sex workers per se, they do indeed hire women with higher portable earnings capacity. Essay 4: (with Peter Nilsson) We analyze how peer effects among co‑workers affect fertility using population‑wide matched employer-employee panel data. We provide evidence on if, when, why and for whom co‑workers’ fertility decisions matter. Overall the impact of co-workers on own fertility is of the same magnitude as the effect of being one year older in the age span 20 to 30. “Same-type” co‑workers are particularly influential, although social status and own previous childbearing experiences modify the influence of peers in distinct ways. Peers’ fertility decisions matter most when the uncertainty about job-related costs of childbearing is low. The results provide insights to the sharp fluctuations in fertility rates observed in many countries, and give an indication of how social interactions affect important career related decisions.
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| 9. |
- Jazin, Elena, et al.
(författare)
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Trypanosoma cruzi exoantigen is a member of a 160 kDa gene family
- 1995
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Ingår i: Parasitology. - 0031-1820 .- 1469-8161. ; 110:Pt1, s. 61-69
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Tidskriftsartikel (refereegranskat)abstract
- During the chronic stage of Chagas disease a 160 kDa antigen appears in the blood of patients and remains detectable many years after the onset of the disease. This antigen is secreted by the trypomastigote form of the parasite while it is undetectable in the epimastigote form. We report here that the chronic 160 kDa exoantigen is encoded by a gene family (CEA 160 family). We describe the cloning and partial nucleotide sequence of a gene (CEA 160-1) belonging to the CEA160 family. Comparison of the gene sequence with other sequences present in the databases revealed homologies with several Trypanosoma cruzi surface antigens. Highest amino acid identity (59%) was with members of a family containing epitopes that mimic nervous tissues (Van Voorhis et al. 1993). Another related group (18-22% amino acid identity) comprises proteins of 85 or 160 kDa sharing an amino acid motif that is conserved among bacterial neuraminidases (Fouts et al. 1991; Pollevick et al. 1991; Kahn et al. 1991; Takle & Cross, 1991; Franco et al. 1993). The amino acid identities with the different antigens were not homogeneously distributed. Regions of higher identity (40-60%) were grouped in the central region of each protein.
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| 10. |
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