Biology subjects

Wulf, K.

Publications and source records attributed to Wulf, K..

3 recordsLinked to original sources

bioRxiv2026

Topographic structure and function of locus coeruleus norepinephrine neurons

Norepinephrine (NE) is released throughout most of the central nervous system by neurons in the locus coeruleus (LC). We found a relationship between the morphologies, gene expression, and activity of LC-NE neurons in mice. Axonal projections of individual neurons were extensive but largely confined to subsets of brain regions. Axonal projections and graded gene expression correlated with locations of cell bodies in LC. In a behavioral task requiring ongoing learning from actions, neurons in dorsal LC projecting to the cerebral cortex were excited when mice made a different choice from the previous one and by reward prediction errors, a signal driving learning. Background activity of neurons in ventral LC was higher when mice ignored stimuli indicating potential reward availability. These observations reveal a topographically organized structure and function of a neurotransmitter system and show that it contains learning signals for flexible behavior.

neuroscience↗

bioRxiv2025

Larger hybrid clutch size could drive regional displacement of native Iguana populations across the Lesser Antilles

Native Iguana populations across the Caribbean Lesser Antilles are being replaced by non-native green iguanas (NNGI) once these establish themselves, leading to eventual extinction. Despite this knowledge, and much effort towards NNGI removal and prevention of incursions, the underlying mechanisms of the observed genetic swamping are poorly understood. Previous studies show that larger clutch size is a key reproductive trait of mainland as opposed to insular lizard populations. Higher clutch size in NNGI and their progeny could be a driver in the genetic swamping of insular Iguana populations. We collected data on snout-vent length, tail length, clutch size and genetics opportunistically during an eradication program of hybrid and NNGIs on the island of Saba, home to a native Iguana Iguana population. Data of native and hybrid iguanas from Saba were combined with similar published data from native insular and mainland Iguana populations. Generalized linear modeling revealed that climatic variables could not explain differences in clutch size, in contrast to genetic origins. Our preliminary results show that hybrid iguanas lay significantly more eggs (~40%) than similar-sized native Saba iguanas. Therefore, we suggest that higher hybrid clutch size may be a contributing factor hastening the genetic swamping and declines in native Iguana populations across the Lesser Antilles. Further study is needed to clarify and better understand the drivers of the rapid genetic swamping and loss of Antillean iguana diversity, which should also focus on Iguana delicatissima and utilize genomic approaches to pinpoint genes under selection.

ecology↗

bioRxiv2023

CLE11 and CLE10 Suppress Mycorrhizal Colonisation in Tomato

Symbioses with beneficial microbes are widespread in plants, but these relationships must balance the energy invested by the plants with the nutrients acquired. Symbiosis with arbuscular mycorrhizal (AM) fungi occurs throughout land plants but our understanding of the genes and signals that regulate colonisation levels is limited. Here, we demonstrate that in tomato two CLV3/EMBRYO-SURROUNDING REGION (CLE) peptides, SlCLE10 and SlCLE11, act to suppress AM colonisation of roots. Mutant studies and overexpression via hairy transformation indicate SlCLE11 acts locally in the root to limit AM colonisation. Indeed, SlCLE11 expression is strongly induced in AM colonised roots but SlCLE11 is not required for phosphate suppression of AM colonisation. SlCLE11 may act through as yet uncharacterised signalling pathways, as SlCLE11 does not suppress AM colonisation by acting through two previously characterised receptors with roles in regulating AM colonisation, SlFAB (CLAVATA1 orthologue) or SlCLV2. SlCLE10 appears to play a more minor or redundant role, as cle10 mutants did not influence AM, although the fact that ectopic overexpression of SlCLE10 did suppress colonisation suggests SlCLE10 may play a role in regulating AM colonisation. Our findings show that CLE peptides regulate AM colonisation in the non-legume species tomato.

plant biology↗