| 1. |
- Stajich, Jason E., et al.
(författare)
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Insights into evolution of multicellular fungi from the assembled chromosomes of the mushroom Coprinopsis cinerea (Coprinus cinereus)
- 2010
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Ingår i: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 107:26, s. 11889-11894
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Tidskriftsartikel (refereegranskat)abstract
- The mushroom Coprinopsis cinerea is a classic experimental model for multicellular development in fungi because it grows on defined media, completes its life cycle in 2 weeks, produces some 10(8) synchronized meiocytes, and can be manipulated at all stages in development by mutation and transformation. The 37-megabase genome of C. cinerea was sequenced and assembled into 13 chromosomes. Meiotic recombination rates vary greatly along the chromosomes, and retrotransposons are absent in large regions of the genome with low levels of meiotic recombination. Single-copy genes with identifiable orthologs in other basidiomycetes are predominant in low-recombination regions of the chromosome. In contrast, paralogous multicopy genes are found in the highly recombining regions, including a large family of protein kinases (FunK1) unique to multicellular fungi. Analyses of P450 and hydrophobin gene families confirmed that local gene duplications drive the expansions of paralogous copies and the expansions occur in independent lineages of Agaricomycotina fungi. Gene-expression patterns from microarrays were used to dissect the transcriptional program of dikaryon formation (mating). Several members of the FunK1 kinase family are differentially regulated during sexual morphogenesis, and coordinate regulation of adjacent duplications is rare. The genomes of C. cinerea and Laccaria bicolor, a symbiotic basidiomycete, share extensive regions of synteny. The largest syntenic blocks occur in regions with low meiotic recombination rates, no transposable elements, and tight gene spacing, where orthologous single-copy genes are overrepresented. The chromosome assembly of C. cinerea is an essential resource in understanding the evolution of multicellularity in the fungi.
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| 2. |
- Diez, A A, et al.
(författare)
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The Escherichia coli ftsK1 mutation attenuates the induction of sigma(s)-dependent genes upon transition to stationary phase
- 2002
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Ingår i: FEMS Microbiology Letters. - 1574-6968. ; 206:1, s. 19-23
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Tidskriftsartikel (refereegranskat)abstract
- A mutation in the cell division gene ftsK causes super-induction of sigma(70)-dependent stress defense genes, such as uspA, during entry of cells into stationary phase. In contrast, we report here that stationary phase induction of sigma(S)-dependent genes, uspB and cfa, is attenuated and that sigma(S) accumulates at a lower rate in ftsK1 cells. Ectopic overexpression of rpoS restored induction of the rpoS regulon in the ftsK mutant, as did a deletion in the recA gene. Thus, a mutation in the cell division gene,ftsY, uncouples the otherwise coordinated induction of sigma(S)-dependent genes and the universal stress response gene, uspA, during entry into stationary phase. (C) 2002 Federation of European Microbiological Societies, Published by Elsevier Science B.V. All rights reserved.
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| 3. |
- Frostegard, A., et al.
(författare)
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Phospholipid fatty acid composition, biomass, and activity of microbial communities from two soil types experimentally exposed to different heavy metals
- 1993
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Ingår i: Applied and Environmental Microbiology. - 0099-2240. ; 59:11, s. 3605-3617
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Tidskriftsartikel (refereegranskat)abstract
- The phospholipid fatty acid (PLFA) pattern was analyzed in a forest humus and in an arable soil experimentally polluted with Cd, Cu, Ni, Pb, or Zn at different concentrations. In both soil types, there were gradual changes in the PLFA patterns for the different levels of metal contamination. The changes in the forest soil were similar irrespective of which metal was used, while in the arable soil the changes due to Cu contamination differed from those due to the other metals. Several PLFAs reacted similarly to the metal amendments in the two soil types, while others showed different responses. In both soils, the metal pollution resulted in a decrease in the iso-branched PLFAs i15:0 and i17:0 and in the monounsaturated 16:1ω5 and 16:1ω7c fatty acids, while increases were found for i16:0, the branched br17:0 and br18:0, and the cyclopropane cy17:0 fatty acids. In the forest soil, the methyl branched PLFAs 10Me16:0, 10Me17:0, and 10Me18:0 increased in metal-polluted soils, indicating an increase in actinomycetes, while in the arable soil a decrease was found for 10Me16:0 and 10Me18:0 in response to most metals. The bacterial PLFAs 15:0 and 17:0 increased in all metal-contaminated samples in the arable soil, while they were unaffected in the forest soil. Fatty acid 18:2ω6, which is considered to be predominantly of fungal origin, increased in the arable soil, except in the Cu-amended samples, in which it decreased instead. Effects on the PLFA patterns were found at levels of metal contamination similar to or lower than those at which effects on ATP content, soil respiration, or total amount of PLFAs had occurred.
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| 4. |
- Kohler, Annegret, et al.
(författare)
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Convergent losses of decay mechanisms and rapid turnover of symbiosis genes in mycorrhizal mutualists.
- 2015
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 47:4, s. 176-410
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Tidskriftsartikel (refereegranskat)abstract
- To elucidate the genetic bases of mycorrhizal lifestyle evolution, we sequenced new fungal genomes, including 13 ectomycorrhizal (ECM), orchid (ORM) and ericoid (ERM) species, and five saprotrophs, which we analyzed along with other fungal genomes. Ectomycorrhizal fungi have a reduced complement of genes encoding plant cell wall-degrading enzymes (PCWDEs), as compared to their ancestral wood decayers. Nevertheless, they have retained a unique array of PCWDEs, thus suggesting that they possess diverse abilities to decompose lignocellulose. Similar functional categories of nonorthologous genes are induced in symbiosis. Of induced genes, 7-38% are orphan genes, including genes that encode secreted effector-like proteins. Convergent evolution of the mycorrhizal habit in fungi occurred via the repeated evolution of a 'symbiosis toolkit', with reduced numbers of PCWDEs and lineage-specific suites of mycorrhiza-induced genes.
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| 5. |
- Odham, G., et al.
(författare)
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Mass spectrometric determination of selected microbial constituents using fused silica and chiral glass capillary gas chromatography
- 1982
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Ingår i: Chromatographia. - 0009-5893. ; 16:1, s. 83-86
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Tidskriftsartikel (refereegranskat)abstract
- Applications of quantitative gas chromatography/mass spectrometry (selected ion monitoring) to clinical and ecological microbiology are described. The technique permits determination of selected microbial metabolites and can be used for the rapid diagnosis of, for example, tuberculosis by ion-focusing of specific branch-chain fatty acids. The technique is also used to determine diaminopimelic and muramic acids, and D- and L-amino acids separated by chiral gas chromatography, in the low picogram range. The latter method has the potential to detect and quantitate microbial populations.
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| 6. |
- Odham, G., et al.
(författare)
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Model system for studies of microbial dynamics at exuding surfaces such as the rhizosphere.
- 1986
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Ingår i: Applied and Environmental Microbiology. - 0099-2240. ; 52:1, s. 191-196
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Tidskriftsartikel (refereegranskat)abstract
- An autoclavable all-glass system for studying microbial dynamics at permeable surfaces is described. Standard hydrophobic or hydrophilic membranes (46-mm diameter) of various pore sizes were supported on a glass frit through which nutrient solutions were pumped by a peristaltic pump. The pump provided a precisely controlled flow at speeds of 0.5 to 500 ml of defined or natural cell exudates per h, which passed through the membrane into a receiving vessel. The construction allowed a choice of membranes, which could be modified. The system was tested with a bacterium, isolated from rape plant roots (Brassica napus L.), that was inoculated on a hydrophilic membrane filter and allowed to develop into a biofilm. A defined medium with a composition resembling that of natural rape root exudate was pumped through the membrane at 0.5 ml/h. Scanning electron microscopic examinations indicated that the inoculum formed microcolonies embedded in exopolymers evenly distributed over the membrane surface. The lipid composition and content of poly-beta-hydroxybutyrate in free-living and adhered cells were determined by gas chromatography. The bacterial consumption of amino acids in the exudate was also studied.
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| 7. |
- Zak, Donald R., et al.
(författare)
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Exploring the role of ectomycorrhizal fungi in soil carbon dynamics
- 2019
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Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 223:1, s. 33-39
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Tidskriftsartikel (refereegranskat)abstract
- The extent to which ectomycorrhizal (ECM) fungi enable plants to access organic nitrogen (N) bound in soil organic matter (SOM) and transfer this growth-limiting nutrient to their plant host, has important implications for our understanding of plant–fungal interactions, and the cycling and storage of carbon (C) and N in terrestrial ecosystems. Empirical evidence currently supports a range of perspectives, suggesting that ECM vary in their ability to provide their host with N bound in SOM, and that this capacity can both positively and negatively influence soil C storage. To help resolve the multiplicity of observations, we gathered a group of researchers to explore the role of ECM fungi in soil C dynamics, and propose new directions that hold promise to resolve competing hypotheses and contrasting observations. In this Viewpoint, we summarize these deliberations and identify areas of inquiry that hold promise for increasing our understanding of these fundamental and widespread plant symbionts and their role in ecosystem-level biogeochemistry.
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| 8. |
- Beckman, Jenny, et al.
(författare)
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Efterord
- 2009
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Ingår i: Vetenskapens sociala strukturer. - Lund : Nordic Academic Press. - 9789185509119
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Bokkapitel (populärvet., debatt m.m.)
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| 9. |
- Bååth, E., et al.
(författare)
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Growth of bacteria in the rhizoplane and the rhizosphere of rape seedlings
- 1988
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Ingår i: FEMS Microbiology Letters. - 0378-1097. ; 53:6, s. 355-360
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Tidskriftsartikel (refereegranskat)abstract
- The growth of 10 isolates of rhizosphere bacteria was compared in the rhizoplane (RP), rhizosphere (RS) and non-rhizosphere soil of a model system with rape seedlings growing in sterile sand. The colonization of the RP differed little among isolates. However, the bacterial isolates differed according to their degree of dependence on the root for growth, as judged by RS:RP and plant:non-plant ratios for CFU. These two ratios were correlated with changes in viability and 'physiological status' (as judged by γ values, Hattori, T. (1983) J. Gen. Appl. Microbiol. 29, 9-16).
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| 10. |
- Elmqvist, T., et al.
(författare)
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Sexual dimorphism and between-year variation in flowering, fruit set and pollinator behaviour in a boreal willow
- 1988
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Ingår i: Oikos. - : JSTOR. - 0030-1299. ; 53:1, s. 58-66
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Tidskriftsartikel (refereegranskat)abstract
- In Salix myrsinifolia-phylicifolia, males and females produced approximately the same number of catkins per individual, but males produced more flowers per catkin. Females had a higher concentration of sugars in the nectar than males, but the standing crop of nectar did not differ between sexes. Females had a hexoserich nectar, males a sucrose-dominated nectar. Bumblebees discriminated between male and female willows, but their preference changed during the day and differed between bumblebees with different tongue length. The relative abundance of different species of bumblebees varied considerably between years. Hand-pollination in 2 populations significantly increased both fruit and seed set per catkin. Production of flowers in female plants showed a large between-year variation. Both average fruit set and seed set per fruit were <50% during 1981-1985. Fruit set showed greater variation than did seed set per fruit. The early time of flowering and the strongly female biased sex ratios commonly observed in populations of this willow (60-80% females), increase the risk of pollen limitation. The production of many more flowers than fruist may represent a bet-hedging strategy to match the uncertainty in the conditions for fruit maturation, although it may also be of value as it potentially allows the plant to selectively mature fruits of a high genetic quality. -from Authors
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