| 1. |
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| 2. |
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| 3. |
- Aspan, A, et al.
(författare)
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CDNA CLONING OF PROPHENOLOXIDASE FROM THE FRESH-WATER CRAYFISH PACIFASTACUS-LENIUSCULUS AND ITS ACTIVATION
- 1995
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - 0027-8424 .- 1091-6490. ; 92:4, s. 939-943
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Tidskriftsartikel (refereegranskat)abstract
- Prophenoloxidase (proPO), an enzyme that is the terminal component of the so-called proPO activating system, a defense and recognition system in crustaceans and insects, has been purified and cloned from a crayfish blood cell cDNA library. The deduced ami
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| 4. |
- Assefaw-Redda, Yohannes, 1955-
(författare)
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Hemolin expression during Cecropia development and its effect on malaria parasites
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hemolin is a lepidopteran member of the immunoglobulin superfamily, initially isolated from the giant silkmoth Hyalophora cecropia. Hemolin is also induced by stimulation with microbial cell wall components and was recently shown to be strongly upregulated by baculovirus and double stranded RNA. An interesting characteristic of the protein is that it is not only highly expressed during infection but also during development.The work presented in this thesis investigated the expression of hemolin during oogenesis and embryogenesis in H. cecropia. Vitellogenic follicles from ovaries were analysed for the presence of the protein by immunohistochemistry in whole-mount preparations and in cryosections. PCR was used to show the presence of Hemolin transcripts throughout vitellogenesis and choriogenesis and in fertilized and unfertilized mature eggs and Western blots showed the protein in unfertilized eggs, yolk cells and embryo.Injection of the moulting hormone 20-hydroxyecdysone (20E) into hibernating diapausing pupae (low metabolic state), upregulates Hemolin. When diapausing pupae were treated with 20E and the protein synthesis inhibitor cycloheximide, its expression stayed low. This shows that the hormone indirectly regulates Hemolin by some factor(s) induced by 20E. When both bacteria and 20E were injected into diapausing pupae, an enhanced induction of hemolin gene expression occurred. Despite the seemingly indirect 20E regulation, several putative hormone responsive elements were found in the upstream region of the Hemolin (HRE-IR, HRE-M and MRE). When these elements were analysed by gel electrophoresis mobility shift assays (EMSA) to investigate their binding to nuclear factors, all the sites resulted in specific retarded bands. The HRE-IR binding factor was clearly increased by ecdysone. Last but not least we have investigated the effect of Hemolin on development of the malaria parasite Plasmodium falciparum in the midgut of the Anopheles mosquitoes. Hemolin completely inhibits the development of the parasite into its final transmission stage, the sporozoite. A future goal is to generate para-transgenic mosquitoes, enforced by hemolin, to stop malaria transmission. Importantly, hemolin did not affect the mosquito fecundity when fed to the mosquito. We are currently constructing truncated forms of hemolin to gain insight into which parts are important for its effect on the parasite.
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| 5. |
- Ballesteros, I., et al.
(författare)
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Lack of specificity of the molecular diagnosis method for identification of Aphanomyces astaci
- 2007
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Ingår i: BFPP-CONNAISSANCE ET GESTION DU PATRIMOINE AQUATIQUE. - : EDP Sciences. - 1297-6318. ; :385, s. 17-24
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Tidskriftsartikel (refereegranskat)abstract
- A recent PCR-test developed for identification of Aphanomyces astaci, the organism responsible for crayfish plague, provided false positives for Aphanomyces frigidophilus, Aphanomyces repetans, and some Saprolegnia spp. Real-time PCR showed that with the designed primers, A. astaci and A. frigidophilus cannot be distinguished. The results of this study show that this particular crayfish plague PCR-test ought to be improved and that molecular-based techniques need to be contrasted to histological evidences and disease history.
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| 6. |
- Bangyeekhun, E, et al.
(författare)
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Molecular cloning and characterization of two serine proteinase genes from the crayfish plague fungus, Aphanomyces astaci
- 2001
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Ingår i: Journal of Invertebrate Pathology. - : Elsevier BV. - 0022-2011 .- 1096-0805. ; 77:3, s. 206-216
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Tidskriftsartikel (refereegranskat)abstract
- Two novel genes encoding the serine proteinases, subtilisin (AaSP1) and trypsin (AaSP2), from Aphanomyces astaci were identified. Based on the amino acidconsensus sequences around the catalytic triad of these serine proteinases, degenerated oligonucleotides were designed for isolation of serine proteinase genes from a genomic DNA library. The AaSP1 gene encodes a full-length protein of 515 amino acids as a large precursor of 56 kDa. After cleavage of a predicted leader sequence of 18 residues and a prepeptide of 133 amino acids, the mature enzyme of 364 amino acids is generated with a calculated molecular mass of 39 kDa and a pI of 6.0. The primary sequence of AaSP1 showed similarity to both bacterial subtilisin and fungal subtilisin-like serine proteinases. Southern blot analysis of AaSP1 revealed the presence of at least two subtilisin genes in the A. astaci genome. Northern blot analysis indicated that the size of AaSP1 transcript was 1.6 kb. The AaSP2 gene encodes a prepropeptide of 276 amino acids with a molecular mass of 29 kDa. A mature protein of 237 amino acids is probably generated after cleavage of a 17-residue signal peptide and a 21-amino-acid prepeptide with a predicted molecular mass of 25 kDa and a pI of 6.0. The primary sequence of AaSP2 showed similarity to trypsin enzymes from various organisms. Southern blot analysis revealed the presence of multiple trypsin genes in the A. astaci genome. Northern blot analysis indicated that the size of AaSP2 transcript was 1.0 kb. The regulation of AaSP2 transcription was not controlled by nitrogen catabolic repression. However, the expression of AaSP2 was found to be specifically induced by crayfish plasma, implying a role in pathogenesis toward the crayfish host.
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| 7. |
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| 8. |
- Bangyeekhun, E, et al.
(författare)
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Sequence analysis of the ribosomal internal transcribed spacer DNA of the crayfish parasite Psorospermium haeckeli.
- 2001
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Ingår i: Diseases of Aquatic Organisms. - 0177-5103 .- 1616-1580. ; 46:3, s. 217-22
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Tidskriftsartikel (refereegranskat)abstract
- Two morphotypes of the crayfish parasite Psorospermium haeckeli were isolated from 2 crayfish species of different geographical origin. The oval-shaped sporocysts were obtained from the epidermal and connective tissue beneath the carapace of the noble crayfish Astacus astacus fromSweden and Finland. Elongated spores were isolated from the abdominal muscle tissue of the red swamp crayfish Procambarus clarkii from USA. To compare genetic divergence of 2 morphotypes of the parasite, the ribosomal internal transcribed spacer (ITS) DNA (ITS 1 and ITS 2) and the 5.8S rRNAgene were cloned and sequenced. The analysed region is variable in length, with the ribosomal ITS sequence of the European morphotype longer than the North American one. Sequence diversity is found mainly in ITS 1 and ITS 2 regions, and there is 66% and 58% similarity between the 2 morphotypes,respectively. Thus, analysis of the ribosomal ITS DNA suggests that P. haeckeli forms obtained from Europe and North America are genetically diverse, which supports the previously reported morphological characteristics.
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| 9. |
- Cerenius, Lage, et al.
(författare)
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Aphanomyces astaci and crustaceans.
- 2009
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Ingår i: Oomycete Genetics and Genomics.. - Hoboken, New Jersey : John Wiley & Sons, Inc.. - 9780470255674 ; , s. 425-433
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 10. |
- Cerenius, Lage
(författare)
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Aphanomyces astaci (Crayfish plague)
- 2006
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Ingår i: Atlas of European Crayfish Distribution and Diseases. - : Muséum National d'Histoire Naturelle, Paris, Patrimoines Naturels..
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Bokkapitel (refereegranskat)
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| 11. |
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| 12. |
- Cerenius, Lage, et al.
(författare)
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Biological and Immunological Aspects of Innate Defence Mechanisms Activated by (1,3)- β -Glucans and Related Polysaccharides in Invertebrates
- 2009
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Ingår i: Chemistry, Biochemistry and Biology of (1-›3)-β-Glucans and Related Polysaccharides.. - Burlington, MA : Academic Press. - 9780123739711 ; , s. 563-577
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- (1,3)- β -glucans are powerful stimulants of a wide variety of innate defence reactions in invertebrates. These polysaccharides exert a great influence on reactions such as induction of antimicrobial peptides, cellular defence such as encapsulation and phagocytosis, and on the melanization and coagulation cascades. In most cases, these reactions set up an effective defence against microorganisms containing (1,3)- β -glucans or (1,3;1,6)- β -glucans in their outer structures (i.e. mainly fungi and oomycetes).
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| 13. |
- Cerenius, Lage, et al.
(författare)
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Coagulation in invertebrates
- 2011
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Ingår i: Journal of Innate Immunity. - Basel : S. Karger AG. - 1662-811X .- 1662-8128. ; 3:1, s. 3-8
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Forskningsöversikt (refereegranskat)abstract
- In most animals there is a need to quickly prevent the loss of blood or equivalent fluids through inflicted injuries. In invertebrates with an open circulatory system (and sometimes a hydroskeleton as well) these losses may otherwise soon be fatal. Also, there is a need to prevent microbes that have gained access to the body through the wound from disseminating throughout the open circulatory system. Therefore, many invertebrates possess a coagulation system to prevent such accidents from having too serious consequences. In this review we discuss recent developments in a few animals - mainly arthropods - where more detailed data are available. It is likely, however, that corresponding systems are present in most phyla, but this is still unchartered territory.
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| 14. |
- Cerenius, Lage, et al.
(författare)
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Commentary: variable immune molecules in invertebrates
- 2013
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Ingår i: Journal of Experimental Biology. - Company of Biologists Ltd : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 216:23, s. 4313-4319
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Recently it has become evident that invertebrates may mount a highly variable immune response that is dependent on which pathogen is involved. The molecular mechanisms behind this diversity are beginning to be unravelled and in several invertebrate taxa immune proteins exhibiting a broad range of diversity have been found. In some cases, evidence has been gathered suggesting that this molecular diversity translates into the ability of an affected invertebrate to mount a defence that is specifically aimed at a particular pathogen.
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| 15. |
- Cerenius, Lage, 1956-, et al.
(författare)
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Crayfish immunity : Recent findings
- 2018
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Ingår i: Developmental and Comparative Immunology. - : Elsevier BV. - 0145-305X .- 1879-0089. ; 80, s. 94-98
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Tidskriftsartikel (refereegranskat)abstract
- Freshwater crayfish is an important commodity as well as a successful model for studies on crustacean immunity. Due to the ease with which they are kept and the available methods for hemocyte separation and culture they have proven to be very useful. Here, recent progress regarding pattern recognition, immune effector production and antiviral mechanisms are discussed. Several cases of functional resemblance between vertebrate complement and the crayfish immune reactions are highlighted.
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| 16. |
- Cerenius, Lage, et al.
(författare)
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Crustacean immune responses and their implications for disease control
- 2012
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Ingår i: Infectious disease in aquaculture. - Cambridge : Woodhead Publishing Limited. - 9780857090164 - 9780857095732 ; , s. 69-87
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Bokkapitel (refereegranskat)abstract
- This chapter reviews recent advances in our knowledge of crustacean immunity. Emphasis is given to shrimp due to their importance in aquaculture and trade and to freshwater crayfish since they serve as model organisms for research in crustacean immunology. Crustaceans lack antibodies, interferon and some other components from the mammalian immune arsenal but can still mount an efficient defence against many potential pathogens. Crustacean innate immunity relies on a combination of efficient hemocyte and humoral reactions carried out by plasma proteins.
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| 17. |
- Cerenius, Lage, et al.
(författare)
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Crustacean Immunity
- 2010
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Ingår i: Advances in Experimental Medicine and Biology. - Boston, MA : Springer US. - 0065-2598 .- 2214-8019. ; 708, s. 239-259
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Tidskriftsartikel (refereegranskat)abstract
- This chapter provides a review of recent progress in the elucidation of innate immune mechanisms in crustaceans. Mainly due to the importance of crustacean aquaculture interest in this field is large and the subject for extensive research efforts. Here, we provide detailed data on the molecular characterisation of lectins, antiviral reactions, hemocyte formation and differentiation and on the regulation of innate immune pathways.
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| 18. |
- Cerenius, Lage, et al.
(författare)
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CRUSTACEAN IMMUNITY AND COMPLEMENT - A PREMATURE COMPARISON
- 1995
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Ingår i: American Zoologist. - : Oxford University Press (OUP). - 0003-1569 .- 2162-4445. ; 35:1, s. 60-67
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Tidskriftsartikel (refereegranskat)abstract
- The prophenoloxidase activating system constitutes a system for recognition of foreignness in several invertebrates. The system has been especially well studied in crustaceans and it will now be possible to begin structural comparisons between components
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| 19. |
- Cerenius, Lage, 1956-, et al.
(författare)
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High sequence variability among hemocyte-specific Kazal-type proteinase inhibitors in decapod crustaceans
- 2010
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Ingår i: Developmental and Comparative Immunology. - : Elsevier. - 0145-305X .- 1879-0089. ; 34:1, s. 69-75
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Tidskriftsartikel (refereegranskat)abstract
- Crustacean hemocytes were found to produce a large number of transcripts coding for Kazal-type proteinase inhibitors (KPIs). A detailed study performed with the crayfish Pacifastacus leniusculus and the shrimp Penaeus monodon revealed the presence of at least 26 and 20 different Kazal domains from the hemocyte KPIs, respectively. Comparisons with KPIs from other taxa indicate that the sequences of these domains evolve rapidly. A few conserved positions, e.g. six invariant cysteines were present in all domain sequences whereas the position of P1 amino acid, a determinant for substrate specificity, varied highly. A study with a single crayfish animal suggested that even at the individual level considerable sequence variability among hemocyte KPIs produced exist. Expression analysis of four crayfish KPI transcripts in hematopoietic tissue cells and different hemocyte types suggest that some of these KPIs are likely to be involved in hematopoiesis or hemocyte release as they were produced in particular hemocyte types or maturation stages only.
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| 20. |
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| 21. |
- Cerenius, Lage, 1956-, et al.
(författare)
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Immune properties of invertebrate phenoloxidases
- 2021
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Ingår i: Developmental and Comparative Immunology. - : Elsevier. - 0145-305X .- 1879-0089. ; 122
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Forskningsöversikt (refereegranskat)abstract
- Melanin production from different types of phenoloxidases (POs) confers immunity from a variety of pathogens ranging from viruses and microorganisms to parasites. The arthropod proPO expresses a variety of activities including cytokine, opsonin and microbiocidal activities independent of and even without melanin production. Proteolytic processing of proPO and its activating enzyme gives rise to several peptide fragments with a variety of separate activities in a process reminiscent of vertebrate complement system activation although proPO bears no sequence similarity to vertebrate complement factors. Pathogens influence proPO activation and thereby what types of immune effects that will be produced. An increasing number of specialised pathogens - from parasites to viruses - have been identified who can synthesise compounds specifically aimed at the proPO-system. In invertebrates outside the arthropods phylogenetically unrelated POs are participating in melanization reactions obviously aimed at intruders and/or aberrant tissues.
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| 22. |
- Cerenius, Lage, 1956-, et al.
(författare)
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In vitro effects on bacterial growth of phenoloxidase reaction products
- 2010
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Ingår i: Journal of Invertebrate Pathology. - : Elsevier. - 0022-2011 .- 1096-0805. ; 103:1, s. 21-23
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Tidskriftsartikel (refereegranskat)abstract
- An active phenoloxidase preparation from the freshwater crayfish Pacifastacus leniusculus exhibited a strong antibacterial effect in vitro on the bacteria Aeromonas hydrophila, Escherichia coli, Streptococcus pneumoniae whereas a weaker but still significant effect against Bacillus cereus, Pseudomonas aeruginosa and Staphylococcus aureus. In most cases reduction of bacterial growth was stronger when dopamine was used as substrate as compared to L-dopa. The effect on bacteria was abolished if no substrate was available for the phenoloxidase or in the presence of the phenoloxidase inhibitor phenylthiourea.
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| 23. |
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| 24. |
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| 25. |
- Cerenius, Lage, et al.
(författare)
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Protection of natives in a plague situation.
- 2002
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Ingår i: Bulletin Francais de la Peche et de la Pisciculture. - : EDP Sciences. - 0767-2861. ; 367, s. 909-910
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Tidskriftsartikel (refereegranskat)
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| 26. |
- Cerenius, Lage, et al.
(författare)
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Proteolytic cascades and their involvement in invertebrate immunity
- 2010
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Ingår i: TIBS -Trends in Biochemical Sciences. Regular ed.. - : Elsevier BV. - 0968-0004 .- 1362-4326. ; 35:10, s. 575-583
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Forskningsöversikt (refereegranskat)abstract
- Bacteria and other potential pathogens are cleared rapidly from the body fluids of invertebrates by the immediate response of the innate immune system. Proteolytic cascades, following their initiation by pattern recognition proteins, control several such reactions, notably coagulation, melanisation, activation of the Toll receptor and complement-like reactions. However, there is considerable variation among invertebrates and these cascades, although widespread, are not present in all phyla. In recent years, significant progress has been made in identifying and characterizing these cascades in insects. Notably, recent work has identified several connections and shared principles among the different pathways, suggesting that cross-talk between them may be common.
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| 27. |
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| 28. |
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| 29. |
- Cerenius, Lage, et al.
(författare)
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The proPO-system : pros and cons for its role in invertebrate immunity
- 2008
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Ingår i: Trends in immunology. - : Elsevier BV. - 1471-4906 .- 1471-4981. ; 29:6, s. 263-271
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Forskningsöversikt (refereegranskat)abstract
- Melanisation is an important immune response in many invertebrates. Recent evidence also strongly implies that the melanisation (prophenoloxidase activating) cascade is intimately associated with the appearance of factors stimulating cellular defence by aiding phagocytosis and encapsulation reactions. However, some controversy exists in the field, and at least in flies and mosquitoes, the successful combat of some pathogens does not seem to be dependent on phenoloxidase activity. This may be because of redundancy among separate immune mechanisms, inappropriate testing, species differences or a combination thereof. Recently, by using RNA interference against phenoloxidase or in specific host-pathogen interactions where the pathogen prevents melanin production by the host, convincing data have confirmed the importance of this cascade in invertebrate innate immunity.
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| 30. |
- Dieguez-Uribeondo, Javier, et al.
(författare)
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Pathogens, parasites and ectocommensals.
- 2006
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Ingår i: Atlas of crayfish in Europe. - : Publications Scientifiques du Muséum National d'Histoire Naturelle Vol. 64 “Patrimoines Naturels”. - 9782856535790 - 2856535798 ; , s. 135-155
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Bokkapitel (populärvet., debatt m.m.)
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| 31. |
- Diéguez-Uribeondo, Javier, et al.
(författare)
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Phylogenetic relationships among plant and animal parasites, and saprotrophs in Aphanomyces (Oomycetes)
- 2009
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Ingår i: Fungal Genetics and Biology. - : Elsevier BV. - 1087-1845 .- 1096-0937. ; 46:5, s. 365-376
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Tidskriftsartikel (refereegranskat)abstract
- Molecular phylogenetic relationships among 12 species of Aphanomyces de Bary (Oomycetes) were analyzed based on 108 ITS sequences of nuclear rDNA. Sequences used in the analyses belonged to the major species currently available in pure culture and GenBank. Bayesian, maximum likelihood, and maximum parsimony analyses support that Aphanomyces constitutes a monophyletic group. Three independent lineages were found: (i) plant parasitic, (ii) animal parasitic, and (iii) saprotrophic or opportunistic parasitic. Sexual reproduction appeared to be critical in plant parasites for survival in soil environments while asexual reproduction seemed to be advantageous for exploiting specialization in animal parasitism. Repeated zoospore emergence seems to be an advantageous property for both plant and animal parasitic modes of life. Growth in unspecific media was generally faster in saprotrophs compared with parasitic species. A number of strains and GenBank sequences were found to be misidentified. It was confirmed molecularly that Aphanomyces piscicida and Aphanomyces invadans appear to be conspecific, and found that Aphanomyces iridis and Aphanomyces euteiches are closely related, if not the same, species. This study has shown a clear evolutionary separation between Aphanomyces species that are plant parasites and those that parasitize animals. Saprotrophic or opportunistic species formed a separate evolutionary lineage except Aphanomyces stellatus whose evolutionary position has not yet been resolved.
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| 32. |
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| 33. |
- Diéguez-Uribeondo, Javier, et al.
(författare)
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Physiological characterization of Saprolegnia parasitica isolates from brown trout
- 1996
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486 .- 1873-5622. ; 140:3, s. 247-257
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Tidskriftsartikel (refereegranskat)abstract
- Saprolegnia parasitica has caused large mortalities in brown trout, Salmo trutta, in Spain. Several strains of Saprolegnia parasitica have been isolated from these epizootics and characterized regarding their physiological adaptation and genetic diversity
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| 34. |
- Diéguez-Uribeondo, Javier, et al.
(författare)
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Re-evaluation of the enigmatic species complex Saprolegnia diclina-Saprolegnia parasitica based on morphological, physiological and molecular data
- 2007
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Ingår i: Fungal Genetics and Biology. - : Elsevier BV. - 1087-1845 .- 1096-0937. ; 44:7, s. 585-601
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Tidskriftsartikel (refereegranskat)abstract
- The phylogenetic relationships among isolates of the Saprolegnia diclina-Saprolegnia parasitica complex were investigated based on ITS rDNA sequences, and correlated with morphological and physiological characters. The isolates studied belong to five phylogenetically separate clades. The majority of presumed parasitic isolates, mostly isolated from fish lesions, fell within a clade that comprises isolates which has been variously named as S. diclina Type 1, S. parasitica, Saprolegnia salmonis or just as unnamed Saprolegnia sp. Presence of bundles of long-hooked hairs on secondary cysts, high frequency of retracted germination, and oogonia production at 7 degrees C (when occurring) were characteristic of this clade. A single isolate identified as S. diclina Type 2 clustered in a clade along with Saprolegnia ferax isolates. The isolates identified as S. diclina s. str. (S. diclina Type 3) distributed in two clades and appeared closely related to Saprolegnia multispora and to a number of Chilean isolates identified as Saprolegnia australis. The ITS sequences of clade I were almost identical even though the isolates were of diverse geographical origins and showed physiological and morphological differences and variations in their pathogenicity. This suggest these species reproduces clonally even in apparently sexually competent isolates. Adaptation to parasitism in Saprolegnia might have occurred at spore level by the development of long-hooked hairs to facilitate host attachment and selection of a retracting germination. The use of the name S. parasitica should be assigned to isolates of clade I that contained isolates forming cysts with bundles of long-hooked hairs.
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| 35. |
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| 36. |
- Donpudsa, Suchao, et al.
(författare)
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Proteinase inhibitory activities of two two-domain Kazal proteinase inhibitors from the freshwater crayfish Pacifastacus leniusculus and the importance of the P2 position in proteinase inhibitory activity
- 2010
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Ingår i: Fish and Shellfish Immunology. - : Elsevier BV. - 1050-4648 .- 1095-9947. ; 29:5, s. 716-723
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Tidskriftsartikel (refereegranskat)abstract
- Serine proteinase inhibitors are found ubiquitously in living organisms and involved in homeostasis of processes using proteinases as well as innate immune defense. Two two-domain Kazal-type serine proteinase inhibitors (KPIs), KPI2 and KPI8, have been identified from the hemocyte cDNA library of the crayfish Pacifastacus leniusculus. Unlike other KPIs from P. leniusculus, they are found specific to the hernocytes and contain an uncommon P-2 amino acid residue, Gly. To unveil their inhibitory activities, the two KPIs and their domains were over-expressed. By testing against subtilisin, trypsin, chymotrypsin and elastase, the KPI2 was found to inhibit strongly against subtilisin and weakly against trypsin, while the KPI8 was strongly active against only trypsin. With their P-1 Set and Lys residues, the KPI2_domain2 and KPI8_domain2 were responsible for strong inhibition against subtilisin and trypsin, respectively. Mutagenesis of KPI8_domain1 at P-2 amino acid residue from Gly to Pro, mimicking the P-2 residue of KPI8_domain2, rendered the KPI8_domain1 strongly active against trypsin, indicating the important role of P-2 residue in inhibitory activities of the Kazal-type serine proteinase inhibitors. Only the KPI2 was found to inhibit against the extracellular serine proteinases from the pathogenic oomycete of the freshwater crayfish, Aphanomyces astaci.
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| 37. |
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| 38. |
- Huang, TS, et al.
(författare)
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A cell adhesion protein from the crayfish Pacifastacus leniusculus, a serine proteinase homologue similar to Drosophila masquerade
- 2000
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 275:14, s. 9996-10001
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Tidskriftsartikel (refereegranskat)abstract
- A cDNA encoding a protein resembling masquerade, a serine proteinase homologue expressed during embryogenesis, larval, and pupal development in Drosophila melanogaster, was identified in hemocytes of the adult freshwater crayfish, Pacifastacus leniusculus. The crayfish protein is similar to Drosophila masquerade in the following aspects: (a) overall sequence of the serine proteinase domain, such as the position of three putative disulfide bridges, glycine in the place of the catalytic serine residue, and the presence of a substrate-lining pocket typical for trypsins; (b) the presence of several copies of a disulfide-knotted motif in the putative propeptide. This masquerade-like protein is cleaved into a 27-kDa fragment, which could be detected by immunoblot analysis using an affinity-purified antibody against a synthetic peptide in the C-terminal domain of the protein. The 27-kDa protein could be immunoaffinity-purified from hemocyte lysate supernatant and exhibited cell adhesion activity in vitro, indicating that the C-terminal domain of the crayfish masquerade-like protein mediates cell adhesion.
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| 39. |
- 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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| 40. |
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| 41. |
- Johansson, Karin, 1970-
(författare)
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Interaction Between Drosophila melanogaster mbn-2 Cells and Bacteria
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Innate immunity relies on a repertoire of germline-encoded non-rearranging pattern recognition receptors that bind to invariant microbial surface molecules. This event initiates a number of signal transduction cascades that lead to humoral and cellular defense responses like synthesis of antimicrobial peptides, phagocytosis and coagulation – mechanisms that efficiently fight infectious microorganisms and have been evolutionary conserved to exist in parallel with the antibody-based adaptive immunity found in vertebrates. The fruit fly, Drosophila melanogaster represents a widely used animal model for studies of a pristine innate immune system. Its immune responsive intracellular signalling pathways display a high degree of similarity with the NF-κB /Rel-signalling pathways that mediate the inflammatory response in mammals. Insects are also vectors for medically important parasitic diseases which can trigger immune responses in the vector so basal knowledge about the regulation and function of insect immune systems can contribute to our understanding of inflammation and microbial disease in higher animals and open new strategies for biological vector control. Drosophila hemocytes play a key role in executing and coordinating local and systemic defenses in response to infection. This thesis describes in vitro studies of Drosophila gene expression in response to bacterial infection using the larval hemocyte-like cell line – mbn-2. Our results show that immune challenge with bacterial cell wall components and intact live bacteria induces differential gene expression that gives clues to how cellular immune responses could be activated and regulated.
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| 42. |
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| 43. |
- Lilley, J H, et al.
(författare)
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Molecular characterization of the fish-pathogenic fungus Aphanomyces invadans.
- 2003
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Ingår i: Journal of Fish Diseases. - : Wiley. - 0140-7775 .- 1365-2761. ; 26:5, s. 263-75
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Tidskriftsartikel (refereegranskat)abstract
- Aphanomyces invadans (Saprolegniaceae) is a peronosporomycete fungus associated with the serious fish disease, epizootic ulcerative syndrome (EUS), also known as mycotic granulomatosis. In this study, interspecific relationships were examined between A. invadans isolates and other aquatic animal pathogenic Saprolegniaceae, and saprophytic Saprolegniaceae from EUS-affected areas. Restriction fragment length polymorphisms and sequences of ribosomal DNA confirmed that A. invadans is distinct from all other species studied. A sequence from the internal transcribed spacer region ITS1, unique to A. invadans, was used to design primers for a PCR-based diagnostic test. Intraspecific relationships were also examined by random amplification of polymorphic DNA using 20 isolates of A. invadans from six countries. The isolates showed a high degree of genetic homogeneity using 14 random ten-mer primers. This provides evidence that the fungus has spread across Asia in one relatively rapid episode, which is consistent with reports of outbreaks of EUS. Physiological distinctions between A. invadans and other Aphanomyces species based on a data set of 16 growth parameters showed remarkable taxonomic congruence with the molecular phylogeny.
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| 44. |
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| 45. |
- Lilley, JH, et al.
(författare)
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RAPD evidence for the origin of crayfish plague outbreaks in Britain
- 1997
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Ingår i: Aquaculture. - 0044-8486 .- 1873-5622. ; 157:3-4, s. 181-185
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Tidskriftsartikel (refereegranskat)abstract
- Two isolates of Aphanomyces astaci obtained from diseased white-clawed crayfish (Austropotamobius pallipes) in Herefordshire, England were compared against representative isolates of three groups of the fungus found in Sweden and one from Spain by means of random amplification of polymorphic DNA (RAPD). The English isolates proved to be very similar to a Swedish strain which is considered to have been introduced from North America with shipments of the signal crayfish (Pacifastacus leniusculus) from 1970 onwards, and has since spread to indigenous populations of noble crayfish (Astacus astacus). This strain has not been found to be involved in recent incidences of crayfish plague in Turkey and Spain. It is therefore most likely that at least some of the outbreaks of crayfish plague in England resulted from imports of P. leniusculus from northern Europe after 1970, or directly from North America.
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| 46. |
- Lin, Xionghui, et al.
(författare)
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Purification of properoxinectin, a myeloperoxidase homologue and its activation to a cell adhesion molecule
- 2007
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Ingår i: Biochimica et Biophysica Acta - General Subjects. - : Elsevier BV. - 0304-4165 .- 1872-8006. ; 1770:1, s. 87-93
-
Tidskriftsartikel (refereegranskat)abstract
- Peroxidases are important mediators of innate immune reactions throughout the animal kingdom. In many arthropods a myeloperoxidase homologue, peroxinectin, is known to function as a cell adhesion factor and an opsonin. Here, we report in the freshwater crayfish Pacifastacus leniusculus the isolation of properoxinectin, inactive in cell adhesion, and we also show that properoxinectin is produced in the mature blood cells whereas the hematopoietic tissue contains very little of this protein. Both properoxinectin and peroxinectin are catalytically active as peroxidases, at least when using low molecular weight substrates. The extracellular processing of properoxinectin into an active cell adhesion protein was found to involve proteolytic steps shared with the prophenoloxidase activating system to yield catalytically active phenoloxidase. Thus, the regulation of activities by two ancient metalloproteins, both potentially producing highly toxic substances aimed at pathogens, is carried out by limited proteolysis. The proteolytic processing is triggered in the presence of microbial compounds such as beta-glucans or lipopolysaccharide after the release of properoxinectin and prophenoloxidase activating serine proteinases from the blood cells.
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| 47. |
- Liu, Haipeng, et al.
(författare)
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Antilipopolysaccharide factor interferes with white spot syndrome virus replication in vitro and in vivo in the crayfish Pacifastacus leniusculus
- 2006
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Ingår i: Journal of Virology. - 0022-538X .- 1098-5514. ; 80:21, s. 10365-10371
-
Tidskriftsartikel (refereegranskat)abstract
- In a study of genes expressed differentially in the freshwater crayfish Pacifastacus leniusculus infected experimentally with the white spot syndrome virus (WSSV), one protein, known as antilipopolysaccharide factor (ALF), was chosen, among those whose transcript levels increased upon viral infection, for further studies. ALF RNA interference (RNAi) experiments in whole animals and in cell cultures indicated that ALF can protect against WSSV infection, since knockdown of AILF by RNAi specifically resulted in higher rates of viral propagation. In a cell culture of hematopoietic tissue (Hpt) from P. leniusculus, quantitative PCR showed that knockdown of ALF by RNAi resulted into WSSV levels that were about 10-fold higher than those treated with control double-stranded RNA (dsRNA). In addition, RNAi experiments with other crayfish genes that had been found to be up-regulated by a WSSV infection did not result in any changes of viral loads. Thus, the cell culture does not respond to dsRNA in a similar manner, as shown earlier for dsRNA injected into shrimp, which gave a higher degree of resistance to WSSV infection. If ALF transcription in whole animals was stimulated by the administration of LTV-treated WSSV, a partial protection against a subsequent challenge with the active virus was conferred to the host. This is the first crustacean gene product identified with the capacity to interfere with replication of this important pathogen.
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| 48. |
- Liu, Haipeng, 1976-
(författare)
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Functional Studies of Some Immune Relevant Genes in a Crustacean
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The freshwater crayfish, Pacifastacus leniusculus, mounts a strong innate immune response against microbes such as viruses and bacteria. In this thesis, a novel RNA interference (RNAi) method mediated with histone H2A was developed and applied in crayfish hematopoietic tissue cell cultures for gene functional studies. Further, the interactions between host (crayfish) and pathogens (white spot syndrome virus and Aeromonas hydrophila, respectively) were studied using RNAi technology in live animals. An antilipopolysaccharide factor isolated from viral challenged crayfish by suppression subtractive hybridization was shown to interfere with the propagation of white spot syndrome virus both in vivo and in vitro in crayfish, suggesting an important role of this factor in antiviral defense. Besides, RNAi of phenoloxidase, a critical immune effector involved in melanization, revealed that phenoloxidase activity is necessary for crayfish immune defense against a highly pathogenic bacterial infection in crayfish. In addition, RNAi was also employed to study a marker protein gene involved in hemocyte maturation in crayfish. Taken together, these studies may provide more insights into the immune responses against pathogen invasion as well as hemocyte ontogenesis in crustaceans.
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| 49. |
- Liu, Haipeng, et al.
(författare)
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Phenoloxidase is an important component of the defense against Aeromonas hydrophila infection in a crustacean, Pacifastacus leniusculus
- 2007
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 282:46, s. 33593-33598
-
Tidskriftsartikel (refereegranskat)abstract
- The melanization cascade, in which phenoloxidase is the terminal enzyme, appears to play a key role in recognition of and defense against microbial infections in invertebrates. Here, we show that phenoloxidase activity and melanization are important for the immune defense toward a highly pathogenic bacterium, Aeromonas hydrophila, in the freshwater crayfish, Pacifastacus leniusculus. RNA interference-mediated depletion of crayfish prophenoloxidase leads to increased bacterial growth, lower phagocytosis, lower phenoloxidase activity, lower nodule formation, and higher mortality when infected with this bacterium. In contrast, if RNA interference of pacifastin, an inhibitor of the crayfish prophenoloxidase activation cascade, is performed, it results in lower bacterial growth, increased phagocytosis, increased nodule formation, higher phenoloxidase activity, and delayed mortality. Our data therefore suggest that phenoloxidase is required in crayfish defense against an infection by A. hydrophila, a highly virulent and pathogenic bacterium to crayfish.
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| 50. |
- Lundström, Annika, 1972-
(författare)
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Identification and characterisation of five innate immune genes in the cabbage looper Trichoplusia ni
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- When insects are infected with bacteria, they respond by producing a range of different antibacterial peptides and by activating protease cascades leading to coagulation and melanisation. Cellular defence mechanisms are also involved in killing of microorganisms through phagocytosis and encapsulation.We have found several genes that are upregulated upon bacterial infection in the cabbage looper, Trichoplusia ni, by using the differential display method. Attacin and gloverin are antibacterial proteins previously known from other insect species. Both are glycine-rich proteins that act by disrupting the permeability barrier of the cell membrane.An azurocidin homologue without serine protease activity is expressed exclusively in the insect gut. It is induced by injection of bacteria and by feeding larvae with bacteria. Two amino acid substitutions, serine to glutamate and histidine to serine, in the catalytic triad explain the lack of protease activity.Another protein induced by a bacterial infection is a 3-dehydroecdysone 3b-reductase-like protein (DERH). This protein was detected in integument and hemolymph of T. ni larvae. In addition, it is developmentally regulated. A possible function for DERH is to convert 3-dehydroecdysone into ecdysone, regulating the titer of biologically active ecdysteroids in the larvae.Furthermore, a peptidoglycan recognition protein (PGRP) is upregulated in T. ni by bacterial infection. PGRP is a peptidoglycan- and bacteria binding protein, possibly involved in immune recognition. Homologues were also cloned from mouse and man. The mouse PGRP also binds peptidoglycan, suggesting a functional conservation of the protein from insects to humans.
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