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Corrigendum to ‘Fungal S-adenosylmethionine synthetase and the control of development and secondary metabolism in Aspergillus nidulans’. [Fungal Genet. Biol. 49 (2012) 443–454]
No full textFungal S-adenosylmethionine synthetase and the control of development and secondary metabolism in Aspergillus nidulans
Full text linkThe filamentous fungus Aspergillus nidulans carries a single gene for the S-adenosylmethionine (SAM)
synthetase SasA, whereas many other organisms possess multiple SAM synthetases. The conserved
enzyme catalyzes the reaction of methionine and ATP to the ubiquitous methyl group donor SAM.
SAM is the main methyl group donor for methyltransferases to modify DNA, RNA, protein, metabolites,
or phospholipid target substrates. We show here that the single A. nidulans SAM synthetase encoding
gene sasA is essential. Overexpression of sasA, encoding a predominantly cytoplasmic protein, led to
impaired development including only small sterile fruiting bodies which are surrounded by unusually
pigmented auxiliary Hülle cells. Hülle cells are the only fungal cell type which does not contain significant
amounts of SasA. Sterigmatocystin production is altered when sasA is overexpressed, suggesting
defects in coordination of development and secondary metabolism. SasA interacts with various metabolic
proteins including methionine or mitochondrial metabolic enzymes as well as proteins involved in fungal
morphogenesis. SasA interaction to histone-2B might reflect a putative epigenetic link to gene expression.
Our data suggest a distinct role of SasA in coordinating fungal secondary metabolism and
development
Manipulation of fungal development as source of novel secondary metabolites for biotechnology
Full text linkFungal genomics revealed a large potential of yet-unexplored secondary metabolites, which are not produced during vegetative growth. The discovery of novel bioactive compounds is increasingly gaining importance. The high number of resistances against established antibiotics requires novel drugs to counteract increasing human and animal mortality rates. In addition, growth of plant pathogens has to be controlled to minimize harvest losses. An additional critical issue is the post-harvest production of deleterious mycotoxins. Fungal development and secondary metabolite production are linked processes. Therefore, molecular regulators of development might be suitable to discover new bioactive fungal molecules or to serve as targets to control fungal growth, development, or secondary metabolite production. The fungal impact is relevant as well for our healthcare systems as for agriculture. We propose here to use the knowledge about mutant strains discovered in fungal model systems for a broader application to detect and explore new fungal drugs or toxins. As examples, mutant strains impaired in two conserved eukaryotic regulatory complexes are discussed. The COP9 signalosome (CSN) and the velvet complex act at the interface between development and secondary metabolism. The CSN is a multi-protein complex of up to eight subunits and controls the activation of CULLIN-RING E3 ubiquitin ligases, which mark substrates with ubiquitin chains for protein degradation by the proteasome. The nuclear velvet complex consists of the velvet-domain proteins VeA and VelB and the putative methyltransferase LaeA acting as a global regulator for secondary metabolism. Defects in both complexes disturb fungal development, light perception, and the control of secondary metabolism. The potential biotechnological relevance of these developmental fungal mutant strains for drug discovery, agriculture, food safety, and human healthcare is discussed.Deutsche Forschungsgemeinschaft (DFG) [SFB860, SPP1365, BR1502/11
Erratum for Gerke et al., “Breaking the Silence: Protein Stabilization Uncovers Silenced Biosynthetic Gene Clusters in the Fungus Aspergillus nidulans ”
No full textDraft Genome Sequence of Saccharomyces cerevisiae LW2591Y, a Laboratory Strain for In Vivo Multigene Assemblies
No full textSaccharomyces cerevisiae is an industrially preferred cell factory for the heterologous production of proteins and chemicals. Here, we present the draft genome sequence of the laboratory strain Saccharomyces cerevisiae LW2591Y, which has been designed for robust and efficient assembly of multigene pathways.ABSTRACT Saccharomyces cerevisiae is an industrially preferred cell factory for the heterologous production of proteins and chemicals. Here, we present the draft genome sequence of the laboratory strain Saccharomyces cerevisiae LW2591Y, which has been designed for robust and efficient assembly of multigene pathways.Bundesministerium für Bildung und Forschung https://doi.org/10.13039/501100002347Deutsche Forschungsgemeinschaft https://doi.org/10.13039/50110000165
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Breaking the Silence: Protein Stabilization Uncovers Silenced Biosynthetic Gene Clusters in the Fungus Aspergillus nidulans
Full text linkThe genomes of filamentous fungi comprise numerous putative gene clusters coding for the biosynthesis of chemically and
structurally diverse secondary metabolites (SMs), which are rarely expressed under laboratory conditions. Previous approaches
to activate these genes were based primarily on artificially targeting the cellular protein synthesis apparatus. Here, we applied an
alternative approach of genetically impairing the protein degradation apparatus of the model fungus Aspergillus nidulans by
deleting the conserved eukaryotic csnE/CSN5 deneddylase subunit of the COP9 signalosome. This defect in protein degradation
results in the activation of a previously silenced gene cluster comprising a polyketide synthase gene producing the antibiotic 2,4-
dihydroxy-3-methyl-6-(2-oxopropyl)benzaldehyde (DHMBA). The csnE/CSN5 gene is highly conserved in fungi, and therefore,
the deletion is a feasible approach for the identification of new SMs
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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