Biology subjects

Schmidt-Hohagen, K.

Publications and source records attributed to Schmidt-Hohagen, K..

3 recordsLinked to original sources

bioRxiv2023

Branched chain amino acid synthesis is coupled to TOR activation early in the cell cycle in yeast

How cells coordinate their metabolism with division determines the rate of cell proliferation. Dynamic patterns of metabolite synthesis during the cell cycle are unexplored. We report the first isotope tracing analysis in synchronous, growing budding yeast cells. Synthesis of leucine, a branched-chain amino acid (BCAA), increased through the G1 phase of the cell cycle, peaking later during DNA replication. Cells lacking Bat1, a mitochondrial aminotransferase that synthesizes BCAAs, grew slower, were smaller, and were delayed in the G1 phase, phenocopying cells in which the growth-promoting kinase complex TORC1 was moderately inhibited. Loss of Bat1 lowered the levels of BCAAs and reduced TORC1 activity. Exogenous provision of BCAAs to cells lacking Bat1 promoted cell division and increased TORC1 activity. In wild-type cells, TORC1 activity was dynamic in the cell cycle, starting low in early G1 but increasing later in the cell cycle. These results suggest a link between BCAA synthesis from glucose to TORC1 activation in the G1 phase of the cell cycle.

biochemistry↗

bioRxiv2022

Evolution of resilience against heat stress in a red-tide dinoflagellate

"Red tides" are harmful algal blooms (HABs) caused by dinoflagellate microalgae that accumulate toxins lethal to other organisms, including humans via consumption of contaminated seafood. Increasingly frequent, HABs are driven by a combination of environmental factors including nutrient enrichment, particularly in warm waters. Here, we present the de novo assembled genome (~4.75 Gbp), transcriptome, proteome, and metabolome from Prorocentrum cordatum, a globally abundant, bloom-forming dinoflagellate. Using axenic algal cultures, we studied the molecular mechanisms that underpin response to temperature stress, which is relevant to current ocean warming trends. We discovered a complementary interplay between RNA editing and exon usage that regulates the expression and functional diversity of biomolecules, reflected by reduction in photosynthesis, central metabolism, and protein synthesis. Our multi-omics analyses uncover the molecular response to heat stress in an important HAB species, which is driven by complex gene structures in a large, high-G+C genome, combined with multi-level transcriptional regulation.

genomics↗

bioRxiv2021

Unraveling the critical growth factors for stable cultivation of (nano-sized) Micrarchaeota

Micrarchaeota are members of the archaeal DPANN superphylum. These so far poorly characterized archaea have been found to have reduced genomes and likely depend on interactions with host organisms for growth and survival. Here we report on the enrichment of the first stable co-culture of a member of the Micrarchaeota together with its host, as well as the isolation of the latter. Electron microscopic analysis suggest that growth is dependent on the physical interaction of the two organisms within a biofilm. The interaction seems to be ensured by the necessity to grow in form of a biofilm. Furthermore, transcriptomic analyses indicate a shift towards biofilm formation of the host as a result of co-cultivation. Finally, genomic, metabolomic, extracellular polymeric substance (EPSs) and lipid content analyses reveal that the Micrarchaeon symbiont relies on the acquisition of metabolites from its host and thereby provide first insights into the basis of symbiont-host interactions.

microbiology↗