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Helm, R.

Publications and source records attributed to Helm, R..

3 recordsLinked to original sources

Molecular and phenotypic footprints of climate in native Arabidopsis thaliana

Climate change poses a major threat to humanity by driving biodiversity loss and reducing crop yields1,2. To understand the molecular and developmental impacts of rising temperatures, plant science has relied heavily on the model organism Arabidopsis thaliana. Despite decades of research, its development under fully natural conditions remains poorly understood, and only [~]30% of genes have experimental functional annotations, largely because many functions are subtle or manifest only in specific laboratory or ecological contexts3. Here, we address this gap with a landscape transcriptomic approach that integrates intensive phenotyping and transcriptomic profiling of naturally occurring plants in their native habitats4. Across two contrasting field sites and five growing seasons (2021-2025), we phenotyped more than 3,000 A. thaliana plants and generated >1,600 matching transcriptomes. The resulting >30,000 quantitative trait measurements provide a unique opportunity to link climate fluctuations with plant traits and gene expression. Seasons characterized by extreme temperature anomalies directly influenced plant traits, and climatic variables together explained up to 17% of phenotypic variation. In situ transcriptomes carried clear temperature and local environmental signatures, closely matching temperature-response programs known from the laboratory. Leveraging paired per-plant transcriptomes and phenotypes, we applied machine learning to predict regulators of climate-relevant and other plant traits under natural conditions. The models recovered canonical thermomorphogenesis regulators, including PHYTOCHROME INTERACTING FACTOR 4 (PIF4)5,6, providing ecological evidence that temperature signaling pathways defined in controlled environments operate in the wild, and expanded this regulatory landscape by identifying hormonal receptors, signaling components, and previously uncharacterized genes, some of which we functionally validated. Together, this work demonstrates that landscape transcriptomics, by integrating natural field transcriptomes with phenotypes, and thus, capturing environmental and regulatory states, enables the predictive identification of genetic regulators of temperature responses and broader plant traits. This makes landscape transcriptomics a scalable framework for climate-aware functional genomics in plants.

plant biology↗

Effect of quantified cranial osteopathic manipulation on wild type and transgenic rat models of Alzheimer's disease

Alzheimers Disease is a chronic progressive neurodegenerative disorder that impairs the cerebral lymphatic system and compartmental fluid exchange leading to a decline in cognitive function. Due to the lack of disease modifying medications, non-pharmacological Cranial Osteopathic Manipulation (COM) is evolving as a potential minimally invasive treatment choice. In this work, the effect of quantified COM treatment, using a nanosensor glove, on 3-month-old (Yg) and 18-month-old transgenic (Tg) rat model of Alzheimers Disease were studied using the Morris Water Maze (MWM), Western Blots, and Proteomics and Transcriptomics assays. The results revealed that COM had minimal to no significant difference in the behavioral and biochemical parameters in the Yg rats, suggesting COM treatment was harmless. While COM exhibited no significant differences in Tg rat MWM escape latency, navigation to the platform was significantly different on testing days 5 and 6, with p-values of signed initial heading error were 0.014 and 0.034 respectively. This indicates a difference in learning and spatial working memory. A proteomic assay on Tg rat hippocampus identified 51 significantly differentially expressed proteins with 34 associated with neurological disorders, while transcriptome remained indifferent. In this study, for the first time we have established a technique to quantify the force applied during COM treatment on an animal model of AD, offering a more objective approach for evaluating the effect of such treatments. Our results indicate that a quantifiable COM can be applied to rodents and to study the resulting behavioral and biochemical phenotypes.

bioengineering↗

Palaeogenomic analysis of black rat (Rattus rattus) reveals multiple European introductions associated with human economic history

The distribution of the black rat (Rattus rattus) has been heavily influenced by its association with humans. The dispersal history of this non-native commensal rodent across Europe, however, remains poorly understood, and different introductions may have occurred during the Roman and medieval periods. Here, in order to reconstruct the population history of European black rats, we generated a de novo genome assembly of the black rat, 67 ancient black rat mitogenomes and 36 ancient nuclear genomes from sites spanning the 1st-17th centuries CE in Europe and North Africa. Analyses of mitochondrial DNA confirm that black rats were introduced into the Mediterranean and Europe from Southwest Asia. Genomic analyses of the ancient rats reveal a population turnover in temperate Europe between the 6th and 10th centuries CE, coincident with an archaeologically attested decline in the black rat population. The near disappearance and re-emergence of black rats in Europe may have been the result of the breakdown of the Roman Empire, the First Plague Pandemic, and/or post-Roman climatic cooling.

evolutionary biology↗