94 research outputs found
Trichoderma‐Derived Pentapeptides from the Infected Nest Mycobiome of the Subterranean Termite Coptotermes testaceus
No full textTermites live in a dynamic environment where colony health is strongly influenced by surrounding microbes. However, little is known about the mycobiomes of lower termites and their nests, and how these change in response to disease. Here we compared the individual and nest mycobiomes of a healthy subterranean termite colony (Coptotermes testaceus) to one infected and ultimately eradicated by a fungal pathogen. We identified Trichoderma species in the materials of both nests, but they were also abundant in the infected termites. Methanolic extracts of Trichoderma sp. FHG000531, isolated from the infected nest, were screened for secondary metabolites by UHPLC‐HR MS/MS‐guided molecular networking. We identified many bioactive compounds with potential roles in the eradication of the infected colony, as well as a cluster of six unknown peptides. The novel peptide FE011 was isolated and characterized by NMR spectroscopy. The function of this novel peptide family as well as the role of Trichoderma species in dying termite colonies therefore requires further investigation
Isolation, characterization, and bioactivity profiling of oxazoline containing madurastatin siderophores from Actinomadura sp.
No full textGame theory of undirected graphical models
No full textAn -player game in normal form can be modeled via undirected discrete graphical models where the discrete random variables represent the players and their state spaces are the set of pure strategies. There exists an edge between the vertices of the graphical model whenever there is a dependency between the associated players. We study the Spohn conditional independence (CI) variety , which is the intersection of the independence model with the Spohn variety of the game . We prove a conjecture by the first author and Sturmfels that is of codimension in for a generic game with binary choices. We show that the set of totally mixed CI equilibria i.e., the restriction of the Spohn CI variety to the open probability simplex is a smooth semialgebraic manifold for a generic game with binary choices. If the undirected graph is a disjoint union of cliques, we analyze certain algebro-geometric features of Spohn CI varieties and prove affine universality theorems.30 pages, 4 figure
The positive effect of plant diversity on soil carbon depends on climate
No full textLittle is currently known about how climate modulates the relationship between plant diversity and soil organic carbon and the mechanisms involved. Yet, this knowledge is of crucial importance in times of climate change and biodiversity loss. Here, we show that plant diversity is positively correlated with soil carbon content and soil carbon-to-nitrogen ratio across 84 grasslands on six continents that span wide climate gradients. The relationships between plant diversity and soil carbon as well as plant diversity and soil organic matter quality (carbon-to-nitrogen ratio) are particularly strong in warm and arid climates. While plant biomass is positively correlated with soil carbon, plant biomass is not significantly correlated with plant diversity. Our results indicate that plant diversity influences soil carbon storage not via the quantity of organic matter (plant biomass) inputs to soil, but through the quality of organic matter. The study implies that ecosystem management that restores plant diversity likely enhances soil carbon sequestration, particularly in warm and arid climates.This article is published as Spohn, M., Bagchi, S., Biederman, L.A. et al. The positive effect of plant diversity on soil carbon depends on climate. Nat Commun 14, 6624 (2023). https://doi.org/10.1038/s41467-023-42340-0. © The Author(s) 2023.This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
Identification of a novel aminopolycarboxylic acid siderophore gene cluster encoding the biosynthesis of ethylenediaminesuccinic acid hydroxyarginine (EDHA)
No full textSpohn M, Edenhart S, Alanjary M, et al. Identification of a novel aminopolycarboxylic acid siderophore gene cluster encoding the biosynthesis of ethylenediaminesuccinic acid hydroxyarginine (EDHA). METALLOMICS. 2018;10(5):722-734.The mechanism of siderophore-mediated iron supply enhances fitness and survivability of microorganisms under iron limited growth conditions. One class of naturally occurring ionophores is the small aminopolycarboxylic acids (APCAs). Although they are structurally related to the most famous anthropogenic chelating agent, ethylenediaminetetraacetate (EDTA), they have been largely neglected by the scientific community. Here, we demonstrate the detection of APCA gene clusters by a computational screening of a nucleotide database. This genome mining approach enabled the discovery of a yet unknown APCA gene cluster in well-described actinobacterial strains, either known for their potential to produce valuable secondary metabolites (Streptomyces avermitilis) or for their pathogenic lifestyle (Streptomyces scabies, Corynebacterium pseudotuberculosis, Corynebacterium ulcerans and Nocardia brasiliensis). The herein identified gene cluster was shown to encode the biosynthesis of APCA, ethylenediaminesuccinic acid hydroxyarginine (EDHA). Detailed and comparatively performed production and transcriptional profiling of EDHA and its biosynthesis genes showed strict iron-responsive biosynthesis
Preemption and a Dilemma for Causal Decision Theory
No full textThis item has been retired at the request of its author
Exchange on Spohn's Laws of Belief
No full textThe authors of the following discussion notes have been working on causation for about 40 years. Woodward’s work culminated in his book Making Things Happen (OUP 2003), Spohn’s work culminated in chapters 14 and 15 of his book The Laws of Belief (OUP 2012), which have almost book-length. Prima facie, their accounts look quite similar; the interventionist theory of causal Bayes nets seems to be their common ground. Therefore, it is important to also see their differences. These are explained in the notes, which mutually discuss their theories of causation. The exchange originates from an Author Meets Critic session at the APA meeting in Baltimore in January 2017
Complete genome sequence of the actinobacterium Amycolatopsis japonica MG417-CF17(T) (=DSM 44213T) producing (S,S)-N,N '-ethylenediaminedisuccinic acid
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