Biology subjects

Schick, J.

Publications and source records attributed to Schick, J..

3 recordsLinked to original sources

bioRxiv2025

Isohydric species show earlier drought-induced declines in stem water content, rehydration, sap flow, and growth than anisohydric species

O_LIIsohydric species reduce water potential fluctuations through more stringent stomatal regulation. It is unclear whether isohydric behavior leads to smaller reversible diurnal stem shrinkage (i.e. greater nocturnal stem rehydration) during drought and a lower drought sensitivity of radial growth compared to anisohydric behavior. C_LIO_LIWith synchronous high-resolution sap flow and dendrometer measurements in mature anisohydric European beech and isohydric Douglas fir trees in pure and mixed stands, we quantified declines in stem water content (SWC), stem rehydration, sap flow and radial growth during soil dry-down and determined the critical soil moisture levels (expressed as Relative Extractable Water, REW) and elapsed desiccation time until 30-90% reductions in these traits. C_LIO_LISap flow and growth started to decline in both species at REW [~]0.6, preceding declines in stem rehydration. Water-spending Douglas fir approached 50% drops in SWC, sap flow, stem rehydration and growth during soil dry-down faster than beech, indicating higher drought sensitivity. In mixture, both species reached these reduction levels later than in monoculture, suggesting positive mixing effects on the species drought resistance. C_LIO_LIOur findings demonstrate that SWC, sap flow and radial growth decrease earlier than nocturnal stem rehydration, with isohydric and anisohydric species exhibiting different timelines of physiological downregulation during soil dry-down. C_LI

physiology↗

bioRxiv2023

Spatial organization and function of RNA molecules within phase-separatedcondensates are controlled by Dnd1

Germ granules, condensates of phase-separated RNA and protein, are organelles essential for germline development in different organisms The patterning of the granules and its relevance for germ cell fate are not fully understood. Combining three-dimensional in vivo structural and functional analyses, we study the dynamic spatial organization of molecules within zebrafish germ granules. We find that localization of RNA molecules to the periphery of the granules, where ribosomes are localized depends on translational activity at this location. In addition, we find that the vertebrate-specific Dead end (Dnd1) protein is essential for nanos3 RNA localization at the condensates periphery. Accordingly, in the absence of Dnd1, or when translation is inhibited, nanos3 RNA translocates into the granule interior, away from the ribosomes, a process that is correlated with loss of germ cell fate. These findings highlight the relevance of sub-granule compartmentalization for posttranscriptional control, and its importance for preserving germ cell totipotency.

cell biology↗

bioRxiv2021

IL-4 and helminth infection downregulate MINCLE-dependent macrophage response to mycobacteria and Th17 adjuvanticity

The myeloid C-type lectin receptor (CLR) MINCLE senses the mycobacterial cell wall component trehalose-6,6-dimycolate (TDM). Recently, we found that IL-4 down-regulates MINCLE expression in macrophages. IL-4 is a hallmark cytokine in helminth infections, which appear to increase the risk for mycobacterial infection and active tuberculosis. Here, we investigated functional consequences of IL-4 and helminth infection on MINCLE-driven macrophage activation and Th1/Th17 adjuvanticity. IL-4 inhibited MINCLE and cytokine induction after macrophage infection with Mycobacterium bovis Bacille Calmette-Guerin (BCG). Infection of mice with BCG upregulated MINCLE on myeloid cells, which was inhibited by IL-4 plasmid injection and by infection with the nematode Nippostrongylus brasiliensis in monocytes. To determine the impact of helminth infection on MINCLE-dependent immune responses, we vaccinated mice with a recombinant protein together with the MINCLE ligand Trehalose-6,6-dibehenate (TDB) as adjuvant. Concurrent infection with N. brasiliensis or with Schistosoma mansoni promoted T cell-derived IL-4 production and suppressed Th1/Th17 differentiation in the spleen. In contrast, helminth infection did not reduce Th1/Th17 induction by TDB in draining peripheral lymph nodes, where IL-4 levels were unaltered. Upon use of the TLR4-dependent adjuvant G3D6A, N. brasiliensis infection impaired selectively the induction of splenic antigen-specific Th1 but not of Th17 cells. Thus, helminth infection attenuated the Th17 response to MINCLE-dependent immunization in an organ-specific manner. Taken together, our results demonstrate down-regulation of MINCLE expression on monocytes and macrophages by IL-4 as a possible mechanism of thwarted Th17 vaccination responses by underlying helminth infection.

immunology↗