Higher Levels Of Biological Organization Research Articles

The genetics of plant-plant interactions and their cascading effects on agroecosystem - from model plants to application.

Plants are typically surrounded by neighboring individuals in agricultural fields or natural environments. In such circumstances, plant-plant interactions (PPI) are ubiquitous and represent not only important evolutionary forces but also have consequences on (agro-)ecosystem functioning, such as increased productivity and resistance. However, many mechanisms underlying these PPIs remain poorly understood. Recently, new genomic technologies and tools, such as genome-wide association studies, have facilitated genetic approaches to study PPIs, particularly among conspecific individuals. Here, we highlight emerging issues and advances in the field by focusing on three different aspects. First, we overview the current status of genetic mapping studies on PPIs and pinpoint that these studies open a new opportunity that is relevant to agriculture and breeding. Second, we introduce two proof-of-concept studies in Arabidopsis thaliana, in which genetic differences among plants improved the functioning of genotype mixtures. Both studies were able to predict effective mixtures with different experimental designs applied to different outcomes (productivity increase vs. herbivory mitigation). Third, we discuss implications from these case studies about how PPIs have cascading effects that propagate to higher levels of biological organization, such as populations or communities. At the population level, plant yield or resistance can be optimized through breeding that achieves reduced competition or push-pull protection systems, respectively. At the community level, these population-level changes may have further beneficial effects on plant-associated organisms. Overall, we suggest that the increasing availability of genomic resources will improve our understanding of PPIs and thereby contribute to the management of crops or semi-natural ecosystems.

Regional differences in leaf evolution facilitate photosynthesis following severe drought.

Characterizing physiological and anatomical changes that underlie rapid evolution following climatic perturbation can broaden our understanding of how climate change is affecting biodiversity. It can also provide evidence of cryptic adaptation despite stasis at higher levels of biological organization. Here, we compared evolutionary changes in populations of Mimulus cardinalis from historically different climates in the north and south of the species' range following an exceptional drought. We grew seeds produced from predrought ancestral plants alongside peak-drought descendants in a common glasshouse and exposed them to wet and dry conditions. Before the drought, northern ancestral populations expressed traits contributing to drought escape, while southern ancestral populations expressed drought avoidance. Following the drought, both regions evolved to reduce water loss and maintain photosynthesis in dry treatments (drought avoidance), but via different anatomical alterations in stomata, trichomes, and palisade mesophyll. Additionally, southern populations lost the ability to take advantage of wet conditions. These results reveal rapid evolution towards drought avoidance at an anatomical level following an exceptional drought, but suggest that differences in the mechanisms between regions incur different trade-offs. This sheds light on the importance of characterizing underlying mechanisms for downstream life-history and macromorphological traits.

Chronic effects of commercial pesticide preparations on biomarkers and reproductive success in earthworm Eisenia andrei

Chemical pollution resulting from pesticide usage has been a continuous issue since the 1960s, despite comprehensive European Union legislation designed to safeguard human health and the environment from the adverse effects of pesticides. While regulatory risk assessments primarily focus on the active ingredients, recent research indicates ecotoxicological impacts of commercial preparations on non-target organisms, particularly within the soil ecosystem where key species such as earthworms play a vital role in maintaining soil quality and fertility. Therefore, the aim of this study was the assessment of the long-term effects of the following respective commercial preparations: the insecticides Sumialfa (esfenvalerate) and Calypso (thiacloprid), as well as the herbicides Frontier (dimethenamid-p) and Filon (prosulfocarb) on the earthworm Eisenia andrei in standardized soil during long-term exposures of 7, 14, and 28 days. To study the possible effects on different levels of biological organization, enzymatic biomarkers: acetylcholinesterase (AChE), carboxylesterase (CES) glutathione S-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GPx); non-enzymatic biomarkers: multixenobiotic resistance activity (MXR), levels of glutathione (GSH), and reactive oxygen species (ROS) as well as reproductive success were investigated. While Calypso appeared to be the least toxic substance, all pesticides showed significant effect on multiobiomarker response in E. fetida. That being said, the response of MXR activity was significantly altered by all tested pesticides indicating MXR being the most sensitive endpoint of the present research. Recovery of MXR was observed after 28 days, however, only in case of exposure to Filon, while the recovery of CAT activity was recorded after 28 days as well, subsequent to Sumialfa exposure. Reproductive success was negatively impacted regarding the Frontier and Sumialfa exposure at the highest concentration (100 mg/kg) reflected in reduced number of cocoons, while only the exposure to Frontier (100 mg/kg) reduced the number of juveniles. Based on the results, it is important to include commercial pesticide formulations in pesticide risk assessments. The toxicity classifications of the studied pesticides suggest the potential detrimental consequences to the key soil species in terrestrial ecosystems at various concentrations. Future studies should include other soil species as well as investigation of higher levels of biological organization, i.e., behavioral endpoints, to determine the potential risks to terrestrial ecosystems.

The spatiotemporal context of individual specialization in resource use and environmental associations.

1. Individual niche specialization is widespread in natural populations and has key implications for higher levels of biological organization. This phenomenon, however, has been primarily quantified in resource niche axes, overlooking individual variation in environmental associations (i.e. abiotic conditions organisms experience). 2. Here, we explore what we can learn from a multidimensional perspective of individual niche specialization that integrates resource use and environmental associations into a common framework. 3. By combining predictions from theory and simple simulations, we illustrate how (i) multidimensional intraspecific niche variation and (ii) the spatiotemporal context of interactions between conspecifics scale up to shape emergent patterns of the population niche. 4. Contemplating individual specialization as a multidimensional, unifying concept across biotic and abiotic niche axes is a fundamental step towards bringing this concept closer to the n-dimensional niche envisioned by Hutchinson.

Microplastics and 17α Ethinylestradiol: How Do Different Aquatic Invertebrates Respond to This Combination of Contaminants?

The synthetic hormone 17α ethinyl estradiol (EE2) is a molecule widely used in female contraceptives and recognized as a contaminant of attention (Watch List) in the European Union due to its high consumption, endocrine effects and occurrence in aquatic environments. Its main source of introduction is domestic sewage where it can be associated with other contaminants such as microplastics (MPs). Due to their characteristics, they can combine with each other and exacerbate their isolated effects on biota. This study evaluated the combined effects of microplastics (MPs) and 17α ethinylestradiol (EE2) on two tropical estuarine invertebrate species: Crassostrea gasar and Ucides cordatus. Polyethylene particles were spiked with EE2 and organisms were exposed to three treatments, categorized into three groups: control group (C), virgin microplastics (MPs), and spiked microplastics with EE2 (MPEs). All treatments were evaluated after 3 and 7 days of exposure. Oysters exhibited changes in phase 2 enzymes and the antioxidant system, oxidative stress in the gills, and reduced lysosomal membrane stability after exposure to MPs and MPEs. Crabs exposed to MPs and MPEs after seven days showed changes in phase 1 enzymes in the gills and changes in phases 1 and 2 enzymes in the hepatopancreas, such as disturbed cellular health. The combined effects of microplastics and EE2 increased the toxicity experienced by organisms, which may trigger effects at higher levels of biological organization, leading to ecological disturbances in tropical coastal ecosystems.

Genomic and Epigenomic Influences on Resilience Across Scales: lessons from the responses of fishes to environmental stressors.

Understanding the factors that influence the resilience of biological systems to environmental change is an increasingly critical concern in the face of increasing human impacts on ecosystems and the organisms that inhabit them. However, most considerations of biological resilience have focused at the community and ecosystem levels, whereas here we discuss how including consideration of processes occurring at lower levels of biological organization may provide insights into factors that influence resilience at higher levels of biological organization. Specifically, we explore how processes at the genomic and epigenomic levels may cascade up to influence resilience at higher levels and ask how the concepts of 'resistance', or the capacity of a system to minimize change in response to a disturbance, and 'recovery', or the ability of a system to return to its original state following a disturbance and avoid tipping points and resulting regime shifts map to these lower levels of biological organization. Overall, we argue that substantial changes at these lower levels may be required to support resilience at higher levels, using selected examples of genomic and epigenomic responses of fish to climate-change relevant stressors such as high temperature and hypoxia at the levels of the genome, epigenome and organism.

Life Is Uncertain: Inherent Variability Exhibited by Organisms, and at Higher Levels of Biological Organization.

Organisms act stochastically. A not uncommon view in the ecological literature is that this is mainly due to the observer having insufficient information or a stochastic environment-and not partly because organisms themselves respond with inherent unpredictability. In this study, I compile the evidence that contradicts that view. Organisms generate uncertainty internally, which results in irreducible stochastic responses. I consider why: for instance, stochastic responses are associated with greater adaptability to changing environments and resource availability. Over longer timescales, biologically generated uncertainty influences behavior, evolution, and macroecological processes. Indeed, it could be stated that organisms are systems defined by the internal generation, magnification, and record-keeping of uncertainty as inputs to responses. Important practical implications arise if organisms can indeed be defined by an association with specific classes of inherent uncertainty: not least that isolating those signatures then provides a potential means for detecting life, for considering the forms that life could theoretically take, and for exploring the wider limits to how life might become distributed. These are all fundamental goals in astrobiology.

Non-genetic phenotypic variability affects populations and communities in protist microcosms.

Intraspecific trait variation (ITV), potentially driven by genetic and non-genetic mechanisms, can underlie variability in resource acquisition, individual fitness and ecological interactions. Impacts of ITV at higher levels of biological organizations are hence likely, but up-scaling our knowledge about ITV importance to communities and comparing its relative effects at population and community levels has rarely been investigated. Here, we tested the effects of genetic and non-genetic ITV on morphological traits in microcosms of protist communities by contrasting the effects of strains showing different ITV levels (i.e. trait averages and variance) on population growth, community composition and biomass production. We found that genetic and non-genetic ITV can lead to different effects on populations and communities across several generations. Furthermore, the effects of ITV declined across levels of biological organization: ITV directly altered population performance, with cascading but indirect consequences for community composition and biomass productivity. Overall, these results show that the drivers of ITV can have distinct effects on populations and communities, with cascading impacts on higher levels of biological organization that might mediate biodiversity-ecosystem functioning relationships.

Incorporating otolith-isotope inferred field metabolic rate into conservation strategies.

Fluctuating ocean conditions are rearranging whole networks of marine communities-from individual-level physiological thresholds to ecosystem function. Physiological studies support predictions from individual-level responses (biochemical, cellular, tissue, respiratory potential) based on laboratory experiments. The otolith-isotope method of recovering field metabolic rate has recently filled a gap for the bony fishes, linking otolith stable isotope composition to in situ oxygen consumption and experienced temperature estimates. Here, we review the otolith-isotope method focusing on the biochemical and physiological processes that yield estimates of field metabolic rate. We identify a multidisciplinary pathway in the application of this method, providing concrete research goals (field, modeling) aimed at linking individual-level physiological data to higher levels of biological organization. We hope that this review will provide researchers with a transdisciplinary 'roadmap', guiding the use of the otolith-isotope method to bridge the gap between individual-level physiology, observational field studies, and modeling efforts, while ensuring that in situ data is central in marine policy-making aimed at mitigating climatic and anthropogenic threats.

In vitro screening of per- and polyfluorinated substances (PFAS) for interference with seven thyroid hormone system targets across nine assays

The US Environmental Protection Agency is evaluating the ecological and toxicological effects of per- and polyfluorinated chemicals. A number of perfluorinated chemicals have been shown to impact the thyroid axis in vivo suggesting that the thyroid hormone system is a target of these chemicals. The objective of this study was to evaluate the activity of 136 perfluorinated chemicals at seven key molecular initiating events (MIE) within the thyroid axis using nine in vitro assays. The potential MIE targets investigated are Human Iodothyronine Deiodinase 1 (hDIO1), Human Iodothyronine Deiodinase 2 (hDIO2), Human Iodothyronine Deiodinase 3 (hDIO3), Xenopus Iodothyronine Deiodinase (xDIO3); Human Iodotyrosine Deiodinase (hIYD), Xenopus Iodotyrosine Deiodinase (xIYD), Human Thyroid Peroxidase (hTPO); and the serum binding proteins Human Transthyretin (hTTR) and Human Thyroxine Binding Globulin (hTBG). Of the 136 PFAS chemicals tested, 85 had sufficient activity to produce a half-maximal effect concentration (EC50) in at least one of the nine assays. In general, most of these PFAS chemicals did not have strong potency towards the seven MIEs examined, apart from transthyretin binding, for which several PFAS had potency similar to the respective model inhibitor. These data sets identify potentially active PFAS chemicals to prioritize for further testing in orthogonal in vitro assays and at higher levels of biological organization to evaluate their capacity for altering the thyroid hormone system and causing potential adverse health and ecological effects.

Self-healing demonstration in imidacloprid toxicity with multibiomarkers and biologic pathways

Imidacloprid (IMI) pesticide has significant environmental and ecotoxicological pollution effects. Also, its high potential to enter the aquatic environment reveals the importance of early evaluation of the toxic effects of this compound. This study aimed to evaluate organ responses that can be associated with outcomes at higher levels of biological organization in fish. In this respect, the toxicity mechanism and recovery response process of IMI in rainbow trout (Oncorhyncus mykiss)’ s different tissues (blood, brain, gill and liver) were analyzed with important biomarkers [(hematological indices (RBC, WBC, Hg, Hct, MCV, MCH, MCHC), antioxidant enzyme activities (SOD, CAT, GPx, GSH), MDA, DNA damage (8-OHdG), apoptosis (caspase 3), AChE, TNF α, interleukin 6, Nrf-2, NF-kB activities, histopathological and immunofluorescence analyses (NeuN, BDNF, JNK and Nop10]. Exposure to different concentrations of IMI caused a decrease in RBC, WBC, Hg and Hct levels in O. mykiss. The effect of the same application on brain, gill and liver tissues was determined as inhibitions in antioxidant enzyme activities (SOD, CAT and GPx) and GSH level, inductions on MDA level, DNA damage, caspase-3, TNF α, IL- 6, Nrf-2 and NF-kB activities. As a result of three tissues’ histopathological examination; the degeneration, necrosis and hyperemia in the brain and liver, adhesion, desquamation and inflammation in the lamellar epitheliums has been determined in company with stress-induced responses inducing DNA damage. In the reflection of this situation on histomap results, increases were recorded in BDNF and NeuN levels. In the recovery response, tissue damage profile and detoxification process were differentiated according to dose and marker, and it manifested itself with moderate and mild symptoms. These findings revealed that IMI-mediated oxidative stress was effective in the Nrf-2/GSH/NF-kB pathways, showing strong hemato/hepato, and neurotoxic effects. It has become clear that the severity of the effects caused by IMI exposure is felt more in the brain and liver tissues, and that such contaminants should be taken into account in the risk assessment. During the post-exposure recovery period (after 15 days), AChE activity increased by 21% at high-dose administration. The recovery period was effective in regulating the oxidant/antioxidant balance of the organism by exhibiting serious induction/inhibition in each tissue and biomarker performance.

Development and validation of molecular biomarkers for the green-lipped mussel (Perna canaliculus)

ABSTRACT Globally, there is a move towards using local, native species for ecotoxicological risk assessments. Anthropogenic stressors from urban, agricultural, and industrial activities can impact the health of receiving ecosystems. Biomarkers can provide valuable insights as early warning signals of the potential environmental impacts of stressors. The aim of this study was to develop biomarkers in the green-lipped mussel (Perna canaliculus), a potential bioindicator of environmental health for coastal marine ecosystems in New Zealand. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) assays targeting the expression of genes involved in oxidative stress, xenobiotic transfer, membrane transportation, cellular and DNA response/repair, and endocrine disruption were developed and validated for P. canaliculus. We found significant modulation of genes associated with oxidative stress, xenobiotic transfer, membrane transport, endocrine disruption, and genotoxicity in P. canaliculus following 48-hour exposures to copper and benzo[α]pyrene. These results demonstrate the potential of P. canaliculus as a bioindicator species for environmental risk assessment. The gene expression assays showed potential as early indicators of exposure to the chemicals tested but require additional validation to assess their ability to predict effects at higher levels of biological organisation.

How mitochondria showcase evolutionary mechanisms and the importance of oxygen

Darwinian evolution can be simply stated: natural selection of inherited variations increasing differential reproduction. However, formulated thus, links with biochemistry, cell biology, ecology, and population dynamics remain unclear. To understand interactive contributions of chance and selection, higher levels of biological organization (e.g., endosymbiosis), complexities of competing selection forces, and emerging biological novelties (such as eukaryotes or meiotic sex), we must analyze actual examples. Focusing on mitochondria, I will illuminate how biology makes sense of life's evolution, and the concepts involved. First, looking at the bacterium - mitochondrion transition: merging with an archaeon, it lost its independence, but played a decisive role in eukaryogenesis, as an extremely efficient aerobic ATP generator and internal ROS source. Second, surveying later mitochondrion adaptations and diversifications illustrates concepts such as constructive neutral evolution, dynamic interactions between endosymbionts and hosts, the contingency of life histories, and metabolic reprogramming. Without oxygen, mitochondria disappear; with (intermittent) oxygen diversification occurs in highly complex ways, especially upon (temporary) phototrophic substrate supply. These expositions show the Darwinian model to be a highly fruitful paradigm.

Insights into the molecular mechanisms of pesticide tolerance in the Aporrectodea caliginosa earthworm

Diffuse pollution of the environment by pesticides has become a major soil threat to non-target organisms, such as earthworms for which declines have been reported. However some endogeic species are still abundant and persist in intensively cultivated fields, suggesting they become tolerant to long-term anthropogenic pressure. We thus considered the working hypothesis that populations of Aporrectodea caliginosa earthworms from conventionally managed fields developed a tolerance to pesticides compared with those from organically managed fields. To investigate this hypothesis, we studied earthworm populations of the same genetic lineage from soils that were either lowly or highly contaminated by pesticides to detect any constitutive expression of differentially expressed molecular pathways between these populations. Earthworm populations were then experimentally exposed to a fungicide—epoxiconazole—in the laboratory to identify different molecular responses when newly exposed to a pesticide. State-of-the-art omics technology (RNA sequencing) and bioinformatics were used to characterize molecular mechanisms of tolerance in a non-targeted way. Additional physiological traits (respirometry, growth, bioaccumulation) were monitored to assess tolerance at higher levels of biological organization. In the present study, we generated the de novo assembly transcriptome of A. caliginosa consisting of 64,556 contigs with N50 = 2862 pb. In total, 43,569 Gene Ontology terms were identified for 21,593 annotated sequences under the three main ontologies (biological processes, cellular components and molecular functions). Overall, we revealed that two same lineage populations of A. caliginosa earthworms, inhabiting similar pedo-climatic environment, have distinct gene expression pathways after they long-lived in differently managed agricultural soils with a contrasted pesticide exposure history for more than 22 years. The main difference was observed regarding metabolism, with upregulated pathways linked to proteolytic activities and the mitochondrial respiratory chain in the highly exposed population. This study improves our understanding of the long-term impact of chronic exposure of soil engineers to pesticide residues.

From individual behaviors to collective outcomes: fruiting body formation in Dictyostelium as a group-level phenotype.

Collective phenotypes, which arise from the interactions among individuals, can be important for the evolution of higher levels of biological organization. However, how a group's composition determines its collective phenotype remains poorly understood. When starved, cells of the social amoeba Dictyostelium discoideum cooperate to build a multicellular fruiting body, and the morphology of the fruiting body is likely advantageous to the surviving spores. We assessed how the number of strains, as well as their genetic and geographic relationships to one another, impact the group's morphology and productivity. We find that some strains consistently enhance or detract from the productivity of their groups, regardless of the identity of the other group members. We also detect extensive pairwise and higher-order genotype interactions, which collectively have a large influence on the group phenotype. Whereas previous work in Dictyostelium has focused almost exclusively on whether spore production is equitable when strains cooperate to form multicellular fruiting bodies, our results suggest a previously unrecognized impact of chimeric co-development on the group phenotype. Our results demonstrate how interactions among members of a group influence collective phenotypes and how group phenotypes might in turn impact selection on the individual.

Characterizing the Real‐Time Endogenous Methane Release in a Rat for 26‐days: Effect of Diets, Fasting, and Ethanol Consumption Across Different Time Scales

IntroductionMethane is a byproduct of methanogenic archaea that oxidize H2 gas produced by other microflora in the gut. This methane gas is readily absorbed into the into systemic circulation and excreted in the breath down its concentration gradient (similar to CO2) or may be acutely expelled as flatus. While ruminant animals can generate over 100 liters of methane per day, technological limitations have precluded detailed measurements of methane production and release in humans and other non‐ruminants.MethodsWe paired a Promethion metabolic measurement system with a high‐precision (<1ppb) methane analyzer capable of real‐time methane measurements in an individual mouse or rat. We then subjected a rat to multiple diet switches, 48h of fasting, and ethanol treatments and continuously measured food/water intake, metabolic rate, and methane release over 26 days.ResultsVCO2 responses were unaffected by diet changes and only decreased slightly during the fasting treatment. Methane release was diminished by some diet treatments and could be restored by others. Ethanol had no observable effects. We discovered that methane production generally followed a circadian cycle whereby total rates were ~50% higher and large flatus events were more frequent during the scotophase. Methane release during flatus varied by >1,000‐fold ranging from as little as 0.1 up to 60μl/min. Integrating the continuous data stream (at 1 Hz) we confirmed that the vast majority of methane release occurred in the breath and not in the flatus as is often repeated in the literature. Finally, we provide evidence that the constitutive rate of methane release in the breath is positively correlated with rates of CO2 release, the latter of which is indicative of overall activity levels of the rat.ConclusionGiven the growing number of molecular‐based studies investigating how gut microbiota can alter physiological function at higher levels of biological organization the approach of using real‐time methane measurements promises to provide a powerful new tool to establish causal linkages between microbiome dynamics and whole‐animal responses.

Multilevel mechanism of immune checkpoint inhibitor action in solid tumors: History, present issues and future development.

Immunotherapy with checkpoint inhibitors (antibodies that target and block immune checkpoints in the tumor microenvironment) is included in the standard of care for patients with different types of malignancy, such as melanoma, renal cell and urothelial carcinoma, lung cancer etc. The introduction of this new immunotherapy has altered the view on potential targets for treatment of solid tumors from tumor cells themselves to their immune microenvironment; this has led to a reconsideration of the mechanisms of tumor-associated immunity. However, only a subset of patients benefit from immunotherapy and patient response is often unpredictable, even with known initial levels of prognostic markers; the biomarkers for favorable response are still being investigated. Mechanisms of immune checkpoint inhibitors efficiency, as well as the origins of treatment failure, require further investigation. From a clinical standpoint, discrepancies between the theoretical explanation of inhibitors of immune checkpoint actions at the cellular level and their deployment at a tissue/organ level impede the effective clinical implementation of novel immune therapy. The present review assessed existing experimental and clinical data on functional activity of inhibitors of immune checkpoints to provide a more comprehensive picture of their mechanisms of action on a cellular and higher levels of biological organization.

Hormesis: A General Biological Principle.

Hormesis drives biological modifications from cells to higher levels of biological organization and emerges as a general basic principle of biology, integrating evolution, ecology, medicine, physiology, toxicology, and public health.

Physiological Performance Curves: When Are They Useful?

This review serves as an introduction to a special issue of Frontiers in Physiology, focused on the importance of physiological performance curves across phylogenetic and functional boundaries. Biologists have used performance curves to describe the effects of changing environmental conditions on animal physiology since the late 1800s (at least). Animal physiologists have studied performance curves extensively over the past decades, and there is a good foundation to understanding how the environment affects physiological functions of individuals. Our goal here was to build upon this research and address outstanding questions regarding the mutability and applicability of performance curves across taxonomic groups and levels of biological organization. Performance curves are not fixed at a taxonomic, population, or individual level – rather they are dynamic and can shift in response to evolutionary pressures (e.g., selection) and epigenetic programming (e.g., plasticity). The mechanisms underlying these shifts are being increasingly used to predict the efficacy with which plasticity and heritability of performance curves can render individuals and populations less vulnerable to climate change. Individual differences in physiological performance curves (and plasticity of performance curves) can also have cascading effects at higher levels of biological organization. For instance, individual physiology likely influences group behaviors in non-additive ways. There is a need therefore to extend the concept of performance curves to social interactions and sociality. Collectively, this special issue emphasizes the power of how within- and between-individual shifts in performance curves might scale up to the population-, species-, and community-level dynamics that inform conservation management strategies.

Plumbojarosite Remediation of Soil Affects Lead Speciation and Elemental Interactions in Soil and in Mice Tissues.

Lead (Pb) contamination of soils is of global concern due to the devastating impacts of Pb exposure in children. Because early-life exposure to Pb has long-lasting health effects, reducing exposure in children is a critical public health goal that has intensified research on the conversion of soil Pb to low bioavailability phases. Recently, plumbojarosite (PLJ) conversion of highly available soil Pb was found to decrease Pb relative bioavailability (RBA <10%). However, there is sparse information concerning interactions between Pb and other elements when contaminated soil, pre- and post-remediation, is ingested and moves through the gastrointestinal tract (GIT). Addressing this may inform drivers of effective chemical remediation strategies. Here, we utilize bulk and micro-focused Pb X-ray absorption spectroscopy to probe elemental interactions and Pb speciation in mouse diet, cecum, and feces samples following ingestion of contaminated soils pre- and post-PLJ treatment. RBA of treated soils was less than 1% with PLJ phases transiting the GIT with little absorption. In contrast, Pb associated with organics was predominantly found in the cecum. These results are consistent with transit of insoluble PLJ to feces following ingestion. The expanded understanding of Pb interactions during GIT transit complements our knowledge of elemental interactions with Pb that occur at higher levels of biological organization.