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Siamon Gordon - One of the best experts on this subject based on the ideXlab platform.
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macrophage fusion induced by il 4 alternative activation is a multistage process involving multiple target molecules
European Journal of Immunology, 2007Co-Authors: Laura Helming, Siamon GordonAbstract:Multinucleated giant cells, characteristic of granulomatous infections, originate from fusion of macrophages, however, little is known about the underlying mechanism. Alternative activation of macrophages by exposure to IL-4 and IL-13 induces macrophage Homokaryon formation. We have established a new quantitative bifluorescent system to study IL-4-induced fusion of primary murine macrophages in vitro. Using this assay, we could show that macrophage fusion is not mediated by a single molecule, but involves multiple functional components. Although several murine macrophage populations were not competent to form giant cells, indicating that they fail to display the full fusion machinery, these non-fusogenic macrophages could fuse with fusion-competent macrophages in a heterophilic manner. Since IL-4 induced molecules were needed on both fusion partners, we conclude that at least two functionally distinct molecules mediate macrophage Homokaryon formation with each present on one fusion partner. In addition, though IL-4 treatment led to induction of a fusogenic status, macrophages could only fuse efficiently when adherent to a permissive substratum. Based on our findings, we conclude that macrophage fusion is a multistage process involving multiple target molecules. The model we describe will allow analysis of the molecular basis of membrane fusion and possible insight into alternative activation of macrophages. See accompanying commentary: http://dx.doi.org/10.1002/eji.200636910
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Macrophage fusion induced by IL‐4 alternative activation is a multistage process involving multiple target molecules
European journal of immunology, 2007Co-Authors: Laura Helming, Siamon GordonAbstract:Multinucleated giant cells, characteristic of granulomatous infections, originate from fusion of macrophages, however, little is known about the underlying mechanism. Alternative activation of macrophages by exposure to IL-4 and IL-13 induces macrophage Homokaryon formation. We have established a new quantitative bifluorescent system to study IL-4-induced fusion of primary murine macrophages in vitro. Using this assay, we could show that macrophage fusion is not mediated by a single molecule, but involves multiple functional components. Although several murine macrophage populations were not competent to form giant cells, indicating that they fail to display the full fusion machinery, these non-fusogenic macrophages could fuse with fusion-competent macrophages in a heterophilic manner. Since IL-4 induced molecules were needed on both fusion partners, we conclude that at least two functionally distinct molecules mediate macrophage Homokaryon formation with each present on one fusion partner. In addition, though IL-4 treatment led to induction of a fusogenic status, macrophages could only fuse efficiently when adherent to a permissive substratum. Based on our findings, we conclude that macrophage fusion is a multistage process involving multiple target molecules. The model we describe will allow analysis of the molecular basis of membrane fusion and possible insight into alternative activation of macrophages.
Laura Helming - One of the best experts on this subject based on the ideXlab platform.
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macrophage fusion induced by il 4 alternative activation is a multistage process involving multiple target molecules
European Journal of Immunology, 2007Co-Authors: Laura Helming, Siamon GordonAbstract:Multinucleated giant cells, characteristic of granulomatous infections, originate from fusion of macrophages, however, little is known about the underlying mechanism. Alternative activation of macrophages by exposure to IL-4 and IL-13 induces macrophage Homokaryon formation. We have established a new quantitative bifluorescent system to study IL-4-induced fusion of primary murine macrophages in vitro. Using this assay, we could show that macrophage fusion is not mediated by a single molecule, but involves multiple functional components. Although several murine macrophage populations were not competent to form giant cells, indicating that they fail to display the full fusion machinery, these non-fusogenic macrophages could fuse with fusion-competent macrophages in a heterophilic manner. Since IL-4 induced molecules were needed on both fusion partners, we conclude that at least two functionally distinct molecules mediate macrophage Homokaryon formation with each present on one fusion partner. In addition, though IL-4 treatment led to induction of a fusogenic status, macrophages could only fuse efficiently when adherent to a permissive substratum. Based on our findings, we conclude that macrophage fusion is a multistage process involving multiple target molecules. The model we describe will allow analysis of the molecular basis of membrane fusion and possible insight into alternative activation of macrophages. See accompanying commentary: http://dx.doi.org/10.1002/eji.200636910
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Macrophage fusion induced by IL‐4 alternative activation is a multistage process involving multiple target molecules
European journal of immunology, 2007Co-Authors: Laura Helming, Siamon GordonAbstract:Multinucleated giant cells, characteristic of granulomatous infections, originate from fusion of macrophages, however, little is known about the underlying mechanism. Alternative activation of macrophages by exposure to IL-4 and IL-13 induces macrophage Homokaryon formation. We have established a new quantitative bifluorescent system to study IL-4-induced fusion of primary murine macrophages in vitro. Using this assay, we could show that macrophage fusion is not mediated by a single molecule, but involves multiple functional components. Although several murine macrophage populations were not competent to form giant cells, indicating that they fail to display the full fusion machinery, these non-fusogenic macrophages could fuse with fusion-competent macrophages in a heterophilic manner. Since IL-4 induced molecules were needed on both fusion partners, we conclude that at least two functionally distinct molecules mediate macrophage Homokaryon formation with each present on one fusion partner. In addition, though IL-4 treatment led to induction of a fusogenic status, macrophages could only fuse efficiently when adherent to a permissive substratum. Based on our findings, we conclude that macrophage fusion is a multistage process involving multiple target molecules. The model we describe will allow analysis of the molecular basis of membrane fusion and possible insight into alternative activation of macrophages.
Daniel Cullen - One of the best experts on this subject based on the ideXlab platform.
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Draft Genome Sequence of the White-Rot Fungus Obba rivulosa 3A-2.
Genome Announcements, 2016Co-Authors: Otto Miettinen, Matthieu Hainaut, Robert Riley, Kerrie Barry, Daniel Cullen, Bernard Henrissat, Annele Hatakka, Ronald P. De Vries, Kristiina HildénAbstract:We report here the first genome sequence of the white-rot fungus Obba rivulosa (Polyporales, Basidiomycota), a polypore known for its lignin-decomposing ability. The genome is based on the Homokaryon 3A-2 originating in Finland. The genome is typical in size and carbohydrate active enzyme (CAZy) content for wood-decomposing basidiomycetes.
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A homokaryotic derivative of a Phanerochaete chrysosporium strain and its use in genomic analysis of repetitive elements
Applied and environmental microbiology, 2000Co-Authors: Philip E. Stewart, Jill Gaskell, Daniel CullenAbstract:Analysis of complex gene families in the lignin-degrading basidiomycete Phanerochaete chrysosporium has been hampered by the dikaryotic nuclear condition. To facilitate genetic investigations in P. chrysosporium strain BKM-F-1767, we isolated a Homokaryon from regenerated protoplasts. The nuclear condition was established by PCR amplification of five unlinked genes followed by probing with allele-specific oligonucleotides. Under standard nitrogen-limited culture conditions, lignin peroxidase, manganese peroxidase, and glyoxal oxidase activities of the Homokaryon were equivalent to those of the parental dikaryon. We used the Homokaryon to determine the genomic organization and to assess transcriptional effects of a family of repetitive elements. Previous studies had identified an insertional mutation, Pce1, within lignin peroxidase allele lipI2. The element resembled nonautonomous class II transposons and was present in multiple copies in strain BKM-F-1767. In the present study, three additional copies of the Pce1-like element were cloned and sequenced. The distribution of elements was nonrandom; all localized to the same 3.7-Mb chromosome, as assessed by segregation analysis and Southern blot analysis of the Homokaryon. Reverse transcription-PCR (RT-PCR) showed that Pce1 was not spliced from the lipI2 transcript in either the Homokaryon or the parental dikaryon. However, both strains had equivalent lignin peroxidase activity, suggesting that some lip genes may be redundant.
Mitsuro Hyakumachi - One of the best experts on this subject based on the ideXlab platform.
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Mechanism of the generation of new somatic compatibility groups within Thanatephorus cucumeris (Rhizoctonia solani).
Microbes and environments, 2013Co-Authors: M.g.b. Saldajeno, Mitsuro HyakumachiAbstract:Single-basidiospore isolates (SBIs) were obtained from field isolates of Thanatephorus cucumeris (Rhizoctonia solani) AG-1 IC and AG-2-2 IV. Formation of distinctive tufts, a recognized feature of heterokaryon synthesis, was observed, and isolates derived from hyphal-tipped tuft hyphae were obtained following pairings between various strains. Three distinctive types of tufts were formed: the fibrous type of mating-compatible Homokaryon-Homokaryon (Hom-Hom) pairings, the sparse type between heterokaryon-Homokaryon (Het-Hom) pairings originating from one parent, and the compact type between Het-Hom pairings originating from different parents. Amplified Fragment Length Polymorphism (AFLP) profile of fingerprints of these tuft isolates verified that they were all heterokaryotic. Because of heterokaryotic vigor, the growth and pathogenicity of the majority of tuft isolates increased compared with their contributing SBIs. New somatic compatibility groups (SCGs) that were different from parental field isolates occurred following heterokaryon formation within T. cucumeris. Tuft isolates produced by Hom-Hom and Het-Hom pairings among isolates of different parents yielded no somatic compatibility with the original parent isolates and a high frequency of new SCGs (62–100%). This was in contrast to those produced by Hom-Hom and Het-Hom pairings among isolates with a common parent that yielded only 12–37% new SCGs. The SCG diversity of R. solani in the field may be attributed to new fitter heterokaryons formed between a heterokaryon of one pair of parents and a Homokaryon of another parent pair. This mechanism greatly contributes to genetic diversity in the field and accounts for the failure to recover the expected distribution of SCGs from a field population.
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Mechanism of the Generation of New Somatic Compatibility Groups within Thanatephorus cucumeris (Rhizoctonia solani)
2012Co-Authors: Mary Grace, B. Saldajeno, Mitsuro HyakumachiAbstract:Single-basidiospore isolates (SBIs) were obtained from field isolates of Thanatephorus cucumeris (Rhizoctonia solani) AG-1 IC and AG-2-2 IV. Formation of distinctive tufts, a recognized feature of heterokaryon synthesis, was observed, and isolates derived from hyphal-tipped tuft hyphae were obtained following pairings between various strains. Three distinctive types of tufts were formed: the fibrous type of mating-compatible Homokaryon-Homokaryon (Hom-Hom) pairings, the sparse type between heterokaryon-Homokaryon (Het-Hom) pairings originating from one parent, and the compact type between Het-Hom pairings originating from different parents. Amplified Fragment Length Polymorphism (AFLP) profile of fingerprints of these tuft isolates verified that they were all heterokaryotic. Because of heterokaryotic vigor, the growth and pathogenicity of the majority of tuft isolates increased compared with their contributing SBIs. New somatic compatibility groups (SCGs) that were different from parental field isolates occurred following heterokaryon formation within T. cucumeris. Tuft isolates produced by Hom-Hom and Het-Hom pairings among isolates of different parents yielded no somatic compatibility with the original parent isolates and a high frequency of new SCGs (62–100%). This was in contrast to those produced by Hom-Hom and Het-Hom pairings among isolates with a common parent that yielded only 12–37 % new SCGs. The SCG diversity of R. solani in the field may be attributed to new fitter heterokaryons formed between a heterokaryon of one pair of parents and a Homokaryon of another parent pair. This mechanism greatly contributes to genetic diversity in the field and account
Paul A. Horgen - One of the best experts on this subject based on the ideXlab platform.
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Mitochondrial inheritance and the detection of non-parental mitochondrial DNA haplotypes in crosses of Agaricus bisporus Homokaryons.
Fungal genetics and biology : FG & B, 2003Co-Authors: Paul Y. De La Bastide, Paul A. HorgenAbstract:This study evaluates mtDNA transmission in Agaricus bisporus, as well as the occurrence of non-parental haplotypes in heterokaryons produced by controlled crosses. Sixteen crosses were performed with blended liquid cultures, using different combinations of 13 homokaryotic strains. For each cross, different mtDNA haplotypes were present in each Homokaryon. Heterokaryons generated from these crosses were subject to genetic analysis with RFLP markers to identify (i) karyotic status, (ii) mtDNA haplotype, and (iii) the occurrence of non-parental mtDNA haplotypes. These analyses generally supported the occurrence of uniparental mitochondrial (mt) inheritance in A. bisporus, with one mtDNA haplotype usually favoured in the new heterokaryon. The preponderance of one mtDNA haplotype in a new heterokaryon did not necessarily show a correlation with a greater mycelial growth rate for the parent Homokaryon possessing that haplotype. Mixed mtDNA haplotypes and non-parental haplotypes were also identified in the heterokaryons from some crosses. Evidence for the occurrence of two mtDNA haplotypes in one heterokaryotic mycelium was observed in 8 of 16 crosses, suggesting the maintenance of true heteroplasmons after three successive subculturing steps. Non-parental mtDNA haplotypes were seen in heterokaryons produced from 7 of 16 crosses. The mating protocol described can be utilized to generate novel mtDNA haplotypes for strain improvement and the development of strain-specific markers. Mechanisms of mt selection and inheritance are discussed.
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Somatic recombination in the cultivated mushroom Agaricus bisporus
Mycological Research, 1996Co-Authors: Paul A. Horgen, James B. AndersonAbstract:Agaricus bisporus , the cultivated button mushroom, has a mostly secondarily homothallic life cycle. This mode of sexual reproduction could limit outcrossing and recombination among Homokaryons in natural populations and also creates difficulties in mushroom breeding. An alternative source of recombinant genotypes is from somatic pairings of heterokaryons. In this study, two Homokaryon × heterokaryon and three heterokaryon × heterokaryon pairings were made to examine the possibility of somatic recombination. Four subcultures from the confrontation zone of each pairing were taken for analysis of restriction fragment length polymorphisms at 18 nuclear loci representing seven linkage groups and two regions of mitochondrial DNA. A strikingly high frequency of somatic recombination was observed. Five of the eight subcultures from the two Homokaryon × heterokaryon pairings and five of the 12 subcultures from the three heterokaryon × heterokaryon pairings were recombinant. No loss of marker alleles was detected in any of the self-self pairings of the six original strains. No recombination was observed between the two regions of mtDNA examined in this study. The recombination among nuclear loci involves nuclear reassortment, exchange of genetic material between nuclei, and, in one case, crossing over between markers located on the same chromosome. While the mechanism of somatic recombination in A. bisporus is not known, heterokaryons might be used in pairings with other heterokaryons or with Homokaryons to produce abundant recombinant genotypes for mushroom breeding.
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Electrophoretic karyotype analysis of the button mushroom, Agaricus bisporus
Genome, 1992Co-Authors: John C. Royer, William E. Hintz, Richard W. Kerrigan, Paul A. HorgenAbstract:An efficient procedure is presented for the generation of protoplasts from shake flask cultures of the commercial mushroom Agaricus bisporus. Orthogonal field electrophoresis (OFAGE) of high molecular weight DNA from lysed protoplasts resolved the genome of A. bisporus into at least 10 bands, ranging in size from 1.2 to 4 Mb. The illustrated electrophoretic karyotypes of two Homokaryons were highly polymorphic. A heterokaryon of the two Homokaryons contained a mixture of the two electrophoretic patterns, though the ratio of nuclear types was not equal. A number of RFLP and RAPD markers and the rDNA repeat have been localized to specific chromosomes. Based on ethidium bromide staining intensity and autoradiography, we have estimated the chromosome number of A. bisporus to be 13.Key words: Agaricus bisporus, orthogonal field electrophoresis, RFLP, rDNA.