Biology subjects

Hamberg, M.

Publications and source records attributed to Hamberg, M..

4 recordsLinked to original sources

bioRxiv2026

Old Yellow Enzyme from Brevibacillus nitrificans functions as 12-oxo-phytodienoic acid reductase in planta

Old Yellow Enzymes (OYEs) are a widely distributed family of ene-reductases that were first described in a Saccharomyces cerevisiae ferment. In plants, cis-12-oxo-phytodienoic acid (cis-OPDA) reductase (OPR) is the best studied OYE. In Arabidopsis thaliana, the peroxisomal AtOPR3 was characterized as the major OPDA reductase, which generates 3-oxo-2-(2-pentenyl)-cyclopentane-1-octanoic acid in the jasmonic acid (JA) biosynthesis. In Atopr3 lines, only small amounts of JA are detectable after wounding. Here, we describe an OPR-like enzyme (named BnOPR) from the gram-positive Brevibacillus nitrificans. The sequence was identified in an early version of the Physcomitrium patens genome and is assumed to be a contamination by a bacterium growing in association with P. patens. In complementation experiments with an Atopr3 line, we demonstrate that expression of BnOPR, fused with a peroxisomal targeting signal, rescues the male infertile phenotype and increases JA and JA-Ile levels. The catalytic parameters of BnOPR were determined for a set of substrates, including cis-OPDA and prednisone. Interestingly, B. nitrificans, B. brevis, and Paenibacillus physcomitrellae were shown to have a positive effect on P. patens growth. HighlightThe bacterial enzyme BnOPR rescues the male infertile phenotype of Atopr3 plants.

biochemistry↗

bioRxiv2025

Integrated tissue proteomics and lipidomics from ovine organs suggests novel functional implications for fatty acids and lipid mediators.

Lipid mediators are potent biomolecules that may help to gain specific information about biological processes. However, due to incomplete functional annotations and hence interpretive challenges these molecules are hardly considered in molecular profiling experiments. We hypothesized that correlating lipid mediators extracted from tissues with corresponding proteomics data and the corresponding Gene Ontology terms characteristic of specific tissue types could enable functional annotation of these lipids. Thirteen organs and tissues from sheep (Ovis aries) were analyzed using mass spectrometry-based untargeted proteomics and lipidomics. In total, 4717 proteins and 166 free fatty acids, oxylipins, lysolipids, endocannabinoids, and bile acids were catalogued. This included the previously uncharacterized oxylipin 4-hydroxy-eicosatetraenoic acid (4-HETE), whose identity was confirmed by chemical synthesis. Co-expression and clustering analyses validated our hypothesis, successfully reproducing known and suggesting novel lipid mediator functions. Tissue levels of polyunsaturated fatty acids (PUFAs) correlated with pro-resolving mediators and, unexpectedly, with the cellular protein synthesis and folding machinery. These findings suggest that PUFAs and their derivatives support protein synthesis fidelity and efferocytosis, both essential contributors for the effective resolution of inflammation. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=143 SRC="FIGDIR/small/685055v2_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@126b41org.highwire.dtl.DTLVardef@13fa9adorg.highwire.dtl.DTLVardef@9ccaa1org.highwire.dtl.DTLVardef@1bb429b_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical abstract:C_FLOATNO The Figure was partly generated using Servier Medical Art, provided by Servier, licensed under a Creative Commons Attribution 3.0 Unported license. C_FIG

systems biology↗

bioRxiv2024

Octadecanoids as emerging lipid mediators in cnidarian-dinoflagellate symbiosis

Oxylipin signaling has been suggested as a potential mechanism for the inter-partner recognition and homeostasis regulation of cnidarian-dinoflagellate symbiosis, which maintains the ecological viability of coral reefs. Here we assessed the effects of symbiosis and symbiont identity on a model cnidarian, the sea anemone Exaiptasia diaphana, using mass spectrometry to quantify octadecanoid oxylipins (i.e., 18-carbon-derived oxygenated fatty acids). A total of 84 octadecanoids were reported, and distinct stereospecificity was observed for the synthesis of R- and S-enantiomers for symbiont-free anemones and free-living cultured dinoflagellate symbionts, respectively. Symbiont-derived 13(S)-hydroxy-octadecatetraenoic acid (13(S)- HOTE) linked to a 13S-lipoxygnase was translocated to the host anemone with a 32-fold increase, suggesting it as a biomarker of symbiosis and as a potential agonist of host receptors that regulate inflammatory transcription. Only symbiosis with the native symbiont Breviolum minutum decreased the abundance of pro-inflammatory 9(R)-hydroxy-octadecadienoic acid (9(R)-HODE) in the host. In contrast, symbiosis with the non-native symbiont Durusdinium trenchii was marked by higher abundance of autoxidation-derived octadecanoids, corroborating previous evidence for cellular stress in this association. The putative octadecanoid signaling pathways reported here suggest foundational knowledge gaps that can support the bioengineering and selective breeding of more optimal host-symbiont pairings to enhance resilience and survival of coral reefs.

biochemistry↗

bioRxiv2022

Dosage differences in 12-OXOPHYTODIENOATE REDUCTASE genes modulate wheat primary root growth

Wheat is an essential crop for global food security and is well adapted to a wide variety of soils1. However, the gene networks regulating different root architectures remain poorly understood. We report here the identification of a cluster of a monocot-specific 12-OXOPHYTODIENOATE REDUCTASE genes from subfamily III (OPRIII) that modulate key differences in wheat root architecture associated with grain yield under water-limited conditions. Wheat plants with a loss-of-function mutation in OPRIII showed longer seminal roots, whereas plants with increased OPRIII dosage or transgenic over-expression showed reduced seminal root growth, precocious development of lateral roots and increased jasmonic acid (JA). A JA-biosynthesis inhibitor eliminated the root differences, confirming a JA-mediated mechanism. Multiple transcriptome analysis of transgenic and wild-type lines revealed significant enriched JA-biosynthetic and reactive oxygen species (ROS) pathways that paralleled changes in ROS distribution. The OPRIII genes provide a useful entry point to engineer root architecture in wheat and other cereals.

plant biology↗