Biology subjects

Landau, L.

Publications and source records attributed to Landau, L..

5 recordsLinked to original sources

bioRxiv2026

Land-use intensity overrides grazing and precipitation effects on soil microbial communities in a subtropical agroecosystem

Global change drivers are reshaping agroecosystems and their sustained functions worldwide. While soil microorganisms underpin the resilience of these systems, the individual and interactive effects of multiple anthropogenic stressors on microbial community structure and function using large-scale field experiments remain poorly understood. Here, we utilize a full-factorial field experiment in a subtropical agroecosystem to investigate how land-use intensity, cattle grazing intensity, and altered precipitation regimes interact to shape soil microbiomes. Combining microbiome sequencing with network analyses and functional bioinformatics, we evaluated effects of these drivers on prokaryotic and fungal diversity, composition, predicted functional profiles, and community structure. Land-use intensity emerged as the primary driver of microbial responses, explaining 25% and 13% of the total variation in community composition for prokaryotes and fungi, respectively. Compared to intensively managed pastures, semi-natural pastures had significantly different community composition for prokaryotes and fungi and exhibited 22% higher fungal diversity. Semi-natural pastures were enriched with decomposer-associated taxa and metabolic pathways related to energy and lipid metabolism indicating enhanced microbial activity. Surprisingly, intensively managed pastures showed higher network modularity but lower network richness, suggesting a trade-off between community compartmentalization and complexity under intensive land management. Grazing and precipitation manipulations induced core microbiome changes within land-use intensities but had no impact on overall community structure and no significant interactions with land-use. Together, these findings suggest that long-term land-use legacies exert a persistent influence on soil microbial community structure, function, and organization, shaping the context within which other global change drivers operate in subtropical agroecosystems.

ecology↗

bioRxiv2025

Chronic exposure to PFAS triggers systems-level cellular reprogramming independent of their bioaccumulation

Per- and polyfluoroalkyl substances (PFAS), or "forever chemicals," are linked to metabolic, immune, and neurotoxic disorders, yet their long-term cellular effects remain unclear. Using a 24-week chronic exposure model with non-transformed human epithelial cells, we examined responses to low, environmentally relevant concentrations of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). Integrated transcriptomic and lipidomic analyses revealed that cellular accumulation was minimal, and molecular changes instead emerged around week 17, marked by activation of oxidative stress responses, cell survival pathways, and lipid metabolism. Our data support a multi-faceted model in which PFAS-induced oxidative stress, mediated by SESN2 and SOD3, alongside increased lipid biosynthesis via SREBP axis and compound-specific disruptions of membrane lipids. These findings highlight the importance of multi-omic, time-resolved approaches in uncovering mechanisms of chronic low-dose chemical exposure and provide a foundation for future in vivo studies.

pharmacology and toxicology↗

bioRxiv2024

Emergence of saliva protein genes in the secretory calcium-binding phosphoprotein (SCPP) locus and accelerated evolution in primates

Genes within the secretory calcium-binding phosphoprotein (SCPP) family evolved in conjunction with major evolutionary milestones: the formation of a calcified skeleton in vertebrates, the emergence of tooth enamel in fish, and the introduction of lactation in mammals. The SCPP gene family also contains genes expressed primarily and abundantly in human saliva. Here, we explored the evolution of the saliva-related SCPP genes by harnessing currently available genomic and transcriptomic resources. Our findings provide insights into the expansion and diversification of SCPP genes, notably identifying previously undocumented convergent gene duplications. In primate genomes, we found additional duplication and diversification events that affected genes coding for proteins secreted in saliva. These saliva-related SCPP genes exhibit signatures of positive selection in the primate lineage while the other genes in the same locus remain conserved. We found that regulatory shifts and gene turnover events facilitated the accelerated gain of salivary expression. Collectively, our results position the SCPP gene family as a hotbed of evolutionary innovation, suggesting the potential role of dietary and pathogenic pressures in the adaptive diversification of the saliva composition in primates, including humans.

evolutionary biology↗

bioRxiv2023

Validation of marker-less pose estimation for 3D kinematics during upper limb reaching

Kinematic analysis of movement following brain damage is key for diagnosing motor impairments and for recovery assessment. Advances in computer vision offer novel marker-less tracking tools that could be implemented in the clinic due to their simple operation and affordability. An important question that arises is whether marker-less technologies are sufficiently accurate compared to well established marker-based technologies. This study aims to perform validation of kinematic assessment using two high-speed cameras and a 3D pose estimation model. Four participants performed reaching movements with the upper limb between fixed targets, in different velocities. Movement kinematics were simultaneously measured using the DeepBehavior model and marker-based optical motion capture (QTM), as a gold standard. The differences in corresponding joint angles, estimated from the two different methods throughout the analysis, are presented as a mean absolute error (MAE) of the elbow angle. Quantitatively, the MAE of all movements was relatively small across velocity and joints (~2{degrees}). In a condition where the movements were made towards the DeepBehavior cameras, and the view of the elbow was occluded in one of the cameras, the errors were higher. In conclusion, the results demonstrated that marker-less motion capture is a valid alternative to marker-based motion capture. Inaccuracies of the DeepBehavior system could be explained by occlusions of key-points and are not associated with failure of the pose estimation algorithm.

bioengineering↗

bioRxiv2019

Role of CRF receptor 1 antagonism in the bed nucleus of the stria terminalis of male rats after intermittent social defeat stress

We recently demonstrated that the experience of brief episodes of social defeat caused impairments in social behaviors. Moreover, we provided evidence that the antagonism of corticotropin-releasing factor binding protein (CRFBP) in the bed nucleus of the stria terminalis (BNST) restored social approach in stressed animals. This study aimed to test the relation between corticotropin-releasing factor receptor type 1 (CRFR1) located in the BNST and the establishment of social stress-disrupted behaviors in rats submitted to social defeat in the resident-intruder paradigm. Animals were tested for sweet solution preference, subjected to the elevated-plus maze (EPM), and to the social interaction three-chamber test. Social behavior was tested after BNST drug infusions. The drug used in this study was a CRF receptor 1 antagonist, CP376395 (CP), administered in two doses: 50 ng/0.20 L/side, and 500 ng/0.20 L/side. Saline solution was used as vehicle and administered 0.20 L/side. Socially stressed animals (n = 11) did not differ compared to control animals (n = 11) in the EPM. Stressed animals displayed impaired social behavior, represented by a decrease in time spent in the interaction zone. The lower dose (CP 50 ng/0.20 L/side) administered intra-BNST restored social behaviors in stressed animals. On the other hand, the higher dose of the CRFR1 antagonist (CP 500 ng/0.20 L/side) induced social avoidance in rats without a history of agonistic confrontations. These findings implicate BNST CRFR1 signaling in the modulation of social behaviors in rats given the choice to explore an unfamiliar conspecific.

neuroscience↗