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| 2. |
- Lesch, Christine, et al.
(författare)
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A role for Hemolectin in coagulation and immunity in Drosophila melanogaster
- 2007
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Ingår i: Developmental and Comparative Immunology. - : Elsevier BV. - 0145-305X .- 1879-0089. ; 31:12, s. 1255-1263
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Tidskriftsartikel (refereegranskat)abstract
- Hemolectin has been identified as a candidate clotting factor in Drosophila. We reassessed the domain structure of Hemolectin (Hml) and propose that instead of C-type lectin domains, the two discoidin domains are most likely responsible for the protein's lectin activity. We also tested Hml's role in coagulation and immunity in Drosophila. Here we describe the isolation of a new hml allele in a forward screen for coagulation mutants, and our characterization of this and two other hml alleles, one of which is a functional null. While loss of Hml had strong effects on larval hemolymph coagulation ex vivo, mutant larvae survived wounding. Drosophila thus possesses redundant hemostatic mechanisms. We also found that loss of Hml in immune-handicapped adults rendered them more sensitive to Gram(-) bacteria infection. This demonstrates an immunological role of this clotting protein and reinforces the importance of the clot in insect immunity.
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| 3. |
- Agianian, Bogos, et al.
(författare)
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Preliminary characterization of hemolymph coagulation in Anopheles gambiae larvae
- 2007
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Ingår i: Developmental and Comparative Immunology. - : Elsevier BV. - 0145-305X .- 1879-0089. ; 31:9, s. 879-888
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Tidskriftsartikel (refereegranskat)abstract
- Hemolymph coagulation is a first response to injury, impeding infection, and ending bleeding. Little is known about its molecular basis in insects, but clotting factors have been identified in the fruit fly Drosophila melanogaster. Here, we have begun to study coagulation in the aquatic larvae of the malaria vector mosquito Anopheles gambiae using methods developed for Drosophila. A delicate clot was seen by light microscopy, and pullout and proteomic analysis identified phenoloxidase and apolipophorin-I as major candidate clotting factors. Electron microscopic analysis confirmed clot formation and revealed it contains fine molecular sheets, most likely a result of lipophorin assembly. Phenoloxidase appears to be more critical in clot formation in Anopheles than in Drosophila. The Anopheles larval clot thus differs in formation, structure, and composition from the clot in Drosophila, confirming the need to study coagulation in different insect species to learn more about its evolution and adaptation to different lifestyles.
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| 4. |
- Korayem, Ahmed, et al.
(författare)
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Evidence for an immune function of lepidopteran silk proteins
- 2007
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Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 352:2, s. 317-322
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Tidskriftsartikel (refereegranskat)abstract
- Hemolymph coagulation stops bleeding and protects against infection. Clotting factors include both proteins that are conserved during evolution as well as more divergent proteins in different species. Here we show that several silk proteins also appear in the clot of the greater wax moth Galleria mellonella. RT-PCR analysis reveals that silk proteins are expressed in immune tissues and induced upon wounding in both Galleria and Ephestia kuehniella, a second pyralid moth. Our results support the idea that silk proteins were co-opted for immunity and coagulation during evolution.
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| 5. |
- Rasmusson, Lina M., et al.
(författare)
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Sensitivity of photosynthesis to warming in two similar species of the aquatic angiosperm ruppia from tropical and temperate habitats
- 2021
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Ingår i: Sustainability. - : MDPI AG. - 2071-1050. ; 13:16
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Tidskriftsartikel (refereegranskat)abstract
- Climate change-related events, such as marine heatwaves, are increasing seawater temperatures, thereby putting pressure on marine biota. The cosmopolitan distribution and significant contribution to marine primary production by the genus Ruppia makes them interesting organisms to study thermal tolerance and local adaptation. In this study, we investigated the photosynthetic responses in Ruppia to the predicted future warming in two contrasting bioregions, temperate Sweden and tropical Thailand. Through DNA barcoding, specimens were determined to Ruppia cirrhosa for Sweden and Ruppia maritima for Thailand. Photosynthetic responses were assessed using pulse amplitude-modulated fluorometry, firstly in short time incubations at 18, 23, 28, and 33◦ C in the Swedish set-up and 28, 33, 38, and 43◦ C in the Thai set-up. Subsequent experiments were conducted to compare the short time effects to longer, five-day incubations in 28◦ C for Swedish plants and 40◦ C for Thai plants. Swedish R. cirrhosa displayed minor response, while Thai R. maritima was more sensitive to both direct and prolonged temperature stress with a drastic decrease in the photosynthetic parameters leading to mortality. The results indicate that in predicted warming scenarios, Swedish R. cirrhosa may sustain an efficient photosynthesis and potentially outcompete more heat-sensitive species. However, populations of the similar R. maritima in tropical environments may suffer a decline as their productivity will be highly reduced.
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| 6. |
- Bertrand, Yann, et al.
(författare)
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First Dating of a Recombination Event in Mammalian Tick-borne Flaviviruses
- 2012
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Ingår i: PLoS ONE. - San Francisco : Public Library of Science (PLoS). - 1932-6203. ; 7:2
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Tidskriftsartikel (refereegranskat)abstract
- The mammalian tick-borne flavivirus group (MTBFG) contains viruses associated with important human and animal diseases such as encephalitis and hemorrhagic fever. In contrast to mosquito-borne flaviviruses where recombination events are frequent, the evolutionary dynamic within the MTBFG was believed to be essentially clonal. This assumption was challenged with the recent report of several homologous recombinations within the Tick-borne encephalitis virus (TBEV). We performed a thorough analysis of publicly available genomes in this group and found no compelling evidence for the previously identified recombinations. However, our results show for the first time that demonstrable recombination (i.e., with large statistical support and strong phylogenetic evidences) has occurred in the MTBFG, more specifically within the Louping ill virus lineage. Putative parents, recombinant strains and breakpoints were further tested for statistical significance using phylogenetic methods. We investigated the time of divergence between the recombinant and parental strains in a Bayesian framework. The recombination was estimated to have occurred during a window of 282 to 76 years before the present. By unravelling the temporal setting of the event, we adduce hypotheses about the ecological conditions that could account for the observed recombination.
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| 7. |
- Härlin, Mikael, et al.
(författare)
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Cladistic analysis of the eureptantic nemerteans (Nemertea : Hoplonemertea)
- 1995
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Ingår i: Invertebrate taxonomy. - 0818-0164 .- 1445-4572. ; 9:6, s. 1211-1229
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Tidskriftsartikel (refereegranskat)abstract
- A phylogeny for the 34 species we consider well enough described in the suborder Eureptantia (phylum Nemertea) is inferred by cladistic analysis based on 38 morphological characters. The phylogenetic reconstruction indicates that many previously recognised genera and families are paraphyletic. These findings are discussed and compared with earlier classifications. We also present an identification key to the species based on the cladistic analysis.
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| 8. |
- Härlin, Mikael
(författare)
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Classification nomenclature
- 2004
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Ingår i: McGraw-Hill yearbook of science and technology. - 0076-2016. ; , s. 52-54
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Härlin, Mikael
(författare)
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Definitions and phylogenetic nomenclature
- 2005
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Ingår i: Proceedings of the California Academy of Sciences. ; , s. 216-224
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Konferensbidrag (refereegranskat)abstract
- Recent developments in biological nomenclature suggest advantages of phylogenetic alternatives to more traditional Linnaean approaches. My aim is to discuss some fundamental aspects underlying biological nomenclature in general and phylogenetic nomenclature in particular. A basic assumption, in both traditional and phylogenetic nomenclature, is that taxon names can and should be defined. From the ontological view of individuality I question this view and argue that taxon names only refer since no defining properties are involved for particular clades. Even if we accept the idea that a taxon is a natural kind with a historical essence, and thus has defining properties, I see problems of definitions from an epistemological and inferential point of view. Our conceptualization of phylogeny is dependent on our hypotheses. Therefore, definitions based on discarded hypotheses are problematic. Instead, each new and accepted hypothesis should form the basis of our conceptualization. Another theme in this paper is what should count as the same taxon under different hypotheses. Can a phylogenetic definition guarantee that a name always refers to the same taxon under different hypotheses? I argue that this is questionable. I conclude by suggesting that we need to rethink the role of definition, sameness, and stability in nomenclature. Rethinking these concepts, I believe, will shed some new light on biological nomenclature. My conclusions strongly favor a phylogenetic approach to nomenclature but also suggest that we, besides some practical problems, still have many interesting theoretical and philosophical aspects to take into account.
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| 10. |
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