| 1. |
- Blechert, Oliver, et al.
(författare)
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Conserved function of the Krüppel gap gene in the blowfly Lucilia sericata, despite anterior shift of expression.
- 2011
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Ingår i: Insect Molecular Biology. - : Wiley. - 1365-2583 .- 0962-1075. ; 20, s. 257-265
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Tidskriftsartikel (refereegranskat)abstract
- To determine whether expression patterns of segmentation genes found in Drosophila melanogaster can be scaled to pattern larger insects, we studied the expression of the Krüppel (Kr) gene in the blowfly Lucilia sericata. Compared with Drosophila Kr, L. sericata Kr showed an unexpected 10% shift of expression towards the anterior pole. Furthermore, expression domains not found in D. melanogaster were present at the blastoderm stage of L. sericata. To compare Kr activity and function, we employed RNA interference-mediated gene silencing. We found Kr phenotypes in L. sericata comparable with those observed in D. melanogaster, demonstrating that L. sericata Kr functions as a gap gene as it does in Drosophila. Our results show that, despite an anterior shift in expression, Kr function has remained conserved during the evolution of the blowflies.
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| 2. |
- LaForest, Siana M., et al.
(författare)
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Intraspecific nucleotide variation at the pheromone binding protein locus in the turnip moth, Agrotis segetum
- 1999
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Ingår i: Insect Molecular Biology. - : Wiley. - 0962-1075 .- 1365-2583. ; 8:4, s. 481-490
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Tidskriftsartikel (refereegranskat)abstract
- Inter- and intraspecific amino acid variability in the pheromone binding proteins (PBPs) of the Lepidoptera is believed to contribute to a molecular mechanism of pheromone blend discrimination. Messenger RNA coding for PBP sequence in Agrotis segetum (Noctuidae) was cloned, and nucleotide and inferred amino acid variation across a 769-bp region of a PBP locus was studied in two populations. A single gene copy was fully sequenced, revealing an intron/exon structure conserved with distant saturniids. While several nucleotide substitutions are predicted to result in amino acid replacement, tests for the presence of natural selection suggest that the observed variation is neutral. A phylogenetic analysis provides evidence that the two populations are in the process of genetic isolation.
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| 3. |
- Rosén, Monika, et al.
(författare)
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Extrachromosomal RNA-DNA complex containing long telomeric repeats in chironomids.
- 2002
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Ingår i: Insect Molecular Biology. - : Wiley. - 1365-2583 .- 0962-1075. ; 11:2, s. 167-174
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Tidskriftsartikel (refereegranskat)abstract
- We have analysed an extracted RNase sensitive fraction containing telomeric repeat sequences in the telomerase negative dipteran Chironomus tentans. It shows a slow and well-defined electophoretic migration corresponding to > 20 kb and is sensitive not only to RNase, but also to DNase. It hybridizes to both strands of the telomeric repeat with about equal intensities. DNA is probably the dominant component since the fraction is only slightly heavier than genomic DNA in isopycnic gradients but considerably lighter than RNA. It can, nevertheless, be shown to incorporate tritiated uridine. The material might represent another example of extrachromosomal telomeric repeats in telomerase negative cells.
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| 4. |
- Strandh, Maria, et al.
(författare)
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Transcriptional analysis of the pheromone gland of the turnip moth, Agrotis segetum (Noctuidae), reveals candidate genes involved in pheromone production.
- 2008
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Ingår i: Insect Molecular Biology. - : Wiley. - 1365-2583 .- 0962-1075. ; 17:1, s. 73-85
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Tidskriftsartikel (refereegranskat)abstract
- Moths generally rely on pheromone communication for mate finding. The pheromone components of most moths are produced by a common pathway of fatty-acid biosynthesis coupled with species-specific modifications of the final products. Some genes involved in moth pheromone production have previously been described, whereas others remain to be characterized and thus the molecular mechanisms accounting for the production of species-specific blends are far from understood. The turnip moth, Agrotis segetum, has a multicomponent pheromone, consisting of at least four components derived from palmitic and stearic acid. Different populations produce and respond to different pheromone blends, which makes this species an excellent model for research on genes and molecular mechanisms involved in moth pheromone production. For this purpose, we performed an expressed sequence tag (EST) analysis of two cDNA libraries, one representing the female pheromone gland and the other representing the remainder of the insect body. Among 2285 ESTs analysed altogether, we identified a unigene set of 707 putative gene representatives. The comparative distribution of those in the two libraries showed the transcriptomes of the tissues to be clearly different. One third of the gene representatives were exclusively found in the pheromone gland. From sequence homology to public database information we assigned putative functional roles for a majority of the unigenes and then compared functional profiles of the two tissues. In the set of ESTs more abundant in the pheromone gland library, we found homologues of an acyl-CoA Delta11-desaturase, a G-protein subunit, a chemosensory protein as well as a juvenile hormone binding protein.
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| 5. |
- Shigenobu, S., et al.
(författare)
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Comprehensive survey of developmental genes in the pea aphid, Acyrthosiphon pisum : frequent lineage-specific duplications and losses of developmental genes
- 2010
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Ingår i: Insect molecular biology (Print). - : Wiley. - 0962-1075 .- 1365-2583. ; 19:Supplements2, s. 47-62
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Tidskriftsartikel (refereegranskat)abstract
- Aphids exhibit unique attributes, such as polyphenisms and specialized cells to house endosymbionts, that make them an interesting system for studies at the interface of ecology, evolution and development. Here we present a comprehensive characterization of the developmental genes in the pea aphid, Acyrthosiphon pisum, and compare our results to other sequenced insects. We investigated genes involved in fundamental developmental processes such as establishment of the body plan and organogenesis, focusing on transcription factors and components of signalling pathways. We found that most developmental genes were well conserved in the pea aphid, although many lineage-specific gene duplications and gene losses have occurred in several gene families. In particular, genetic components of transforming growth factor beta (TGF beta) Wnt, JAK/STAT (Janus kinase/signal transducer and activator of transcription) and EGF (Epidermal Growth Factor) pathways appear to have been significantly modified in the pea aphid.
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| 6. |
- Arvestad, Lars, et al.
(författare)
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Expressed sequence tags from the midgut and an epithelial cell line of Chironomus tentans : annotation, bioinformatic classification of unknown transcripts and analysis of expression levels
- 2005
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Ingår i: Insect molecular biology (Print). - : Wiley. - 0962-1075 .- 1365-2583. ; 14:6, s. 689-695
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Tidskriftsartikel (refereegranskat)abstract
- Expressed sequence tags (ESTs) were generated from two Chironomus tentans cDNA libraries, constructed from an embryo epithelial cell line and from larva midgut tissue. 8584 5'-end ESTs were generated and assembled into 3110 tentative unique transcripts, providing the largest contribution of C. tentans sequences to public databases to date. Annotation using BLAST gave 1975 (63.5%) transcripts with a significant match in the major gene/protein databases, 1170 with a best match to Anopheles gambiae and 480 to Drosophila melanogaster. 1091 transcripts (35.1%) had no match to any database. Studies of open reading frames suggest that at least 323 of these contain a coding sequence, indicating that a large proportion of the genes in C. tentans belong to previously unknown gene families.
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| 7. |
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| 8. |
- Calado Botelho, Salomé, et al.
(författare)
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The association of Brahma with the Balbiani ring 1 gene of Chironomus tentans studied by immunoelectron microscopy and chromatin immunoprecipitation
- 2008
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Ingår i: Insect molecular biology (Print). - : Wiley. - 0962-1075 .- 1365-2583. ; 17:5, s. 505-13
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Tidskriftsartikel (refereegranskat)abstract
- Many steps of gene expression take place during transcription, and important functional information can thus be obtained by determining the distribution of specific factors along a transcribed gene. The Balbiani ring (BR) genes of the dipteran Chironomus tentans constitute a unique system for mapping the association of specific factors along a eukaryotic gene using immuno-electron microscopy (immuno-EM). The chromatin immunoprecipitation (ChIP) technique has provided an alternative, more general method for studying the association of proteins with specific genomic sequences. The immuno-EM and the ChIP methods suffer from different limitations, and thus a combination of both is advantageous. We have established optimal conditions for ChIP on chromatin extracted from the salivary glands of C. tentans, and we have analyzed the association of the SWI/SNF chromatin remodelling factor Brahma (Brm) with the BR1 gene by combined immuno-EM and ChIP. We show that Brm is not restricted to the promoter of the BR1 gene but is also associated with sequences in the middle and distal portions of the gene, which suggests that Brm has additional roles apart from regulating transcription initiation.
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| 9. |
- Hirai, Makoto, et al.
(författare)
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Baculovirus and dsRNA induce Hemolin, but no antibacterial activity, in Antheraea pernyi
- 2004
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Ingår i: Insect Molecular Biology. - : Royal Entomological Society. - 0962-1075 .- 1365-2583. ; 13:4, s. 399-405
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Tidskriftsartikel (refereegranskat)abstract
- Hemolin is one of the haemolymph proteins most strongly induced upon bacterial infection in Lepidoptera. When we applied RNA interference (RNAi) to suppress Hemolin expression in the Chinese oak silk moth Antheraea pernyi, we discovered that Hemolin is induced by double-stranded RNA (dsRNA) per se. As dsRNA is recognized as a virus pattern molecule, we then investigated the effect of a baculovirus (ApNPV) infection. We found that Hemolin is induced and expressed with similar kinetics as upon dsRNA injection. Notably, no Attacin gene expression or antibacterial activity was recorded. When baculovirus and high amounts of dsRNA were coinjected, the viral symptoms appeared earlier with Hemolin dsRNA than with GFP dsRNA. This indicates that silencing of hemolin affected the progress of the viral infection.
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| 10. |
- Johansson, Karin C, et al.
(författare)
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Diptericin expression in bacteria infected Drosophila mbn-2 cells - effect of infection dose and phagocytosis.
- 2006
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Ingår i: Insect molecular biology (Print). - : Wiley. - 0962-1075 .- 1365-2583. ; 15:1, s. 57-62
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Tidskriftsartikel (refereegranskat)abstract
- Drosophila haemocytes play a key role in defence against microbial aggression. Their capacity to sense and dispose of bacteria and also to signal to other immune tissues is probably vital to overcome an infection. In this work we used the haemocyte-like mbn-2 cell line to investigate how expression of the antimicrobial peptide diptericin is affected after a high dose bacterial challenge with diaminopimelic acid (DAP)-peptidoglycan Gram-positive and Gram-negative bacteria. We report that diptericin expression is negatively affected by high infection dose and rapid bacterial growth regardless of the type of infection and bacterial virulence and occurs in the absence of mbn-2 cell death. Furthermore we show that the mbn-2 cell population is heterogeneous, containing both phagocytic and nonphagocytic cells and that contact with large numbers of bacteria decreases diptericin expression in the phagocytic cell population.
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