Assessment of ecosystem health disturbance in mangrove-lined Caribbean coastal systems using the oyster Crassostrea rhizophorae as sentinel species

Understanding plant-soil relationships using controlled environment facilities.

Effects of elevated temperatures and cadmium exposure on stress biomarkers at different biological complexity levels in Eisenia fetida earthworms

Integrative assessment of the effects produced by Ag nanoparticles at different levels of biological complexity in Eisenia fetida maintained in two standard soils (OECD and LUFA 2.3)

Assessment of health status of oysters (Crassostreagigas) exposed to environmentally relevant concentrations of Ag and Cu in brackish waters

The effects of climate change on coastal biodiversity are a major concern because altered community compositions may change associated rates of ecosystem functioning and services. Whilst responses of single species or taxa have been studied extensively, it remains challenging to estimate responses to climate change across different levels of biological organisation. Studies that consider the effects of moderate realistic near‐future levels of ocean warming and acidification are needed to identify and quantify the gradual responses of species to change. Also, studies including different levels of biological complexity may reveal opportunities for amelioration or facilitation under changing environmental conditions. To test experimentally for independent and combined effects of predicted near‐future warming and acidification on key benthic species, we manipulated three levels of temperature (winter ambient, +0.8 and +2°C) and two levels of pco2 (ambient at 450 ppm and elevated at 645 ppm) and quantified their effects on mussels and algae growing separately and together (to also test for inter‐specific interactions). Warming increased mussel clearance and mortality rates simultaneously, which meant that total biomass peaked at +0.8°C. Surprisingly, however, no effects of elevated pco2 were identified on mussels or algae. Moreover, when kept together, mussels and algae had mutually positive effects on each other's performance (i.e. mussel survival and condition index, mussel and algal biomass and proxies for algal productivity including relative maximum electron transport rate [rETRmax], saturating light intensity [Ik] and maximum quantum yield [Fv/Fm]), independent of warming and acidification. Our results show that even moderate warming affected the functioning of key benthic species, and we identified a level of resistance to predicted ocean acidification. Importantly, we show that the presence of a second functional group enhanced the functioning of both groups (mussels and algae), independent of changing environmental conditions, which highlights the ecological and potential economic benefits of conserving biodiversity in marine ecosystems.

Multiple-biomarker approach in the assessment of the health status of a novel sentinel mussel Brachidontes rodriguezii in a harbor area

Micro- and nano-plastics activation of oxidative and inflammatory adverse outcome pathways

The health status of ecosystems is the foundation for global climate change adaptation decision-making and a fundamental prerequisite for ensuring regional ecosystem stability. We constructed an ecosystem health assessment indicator system based on a contribution, vigor, organization and resilience model from the perspectives of system integrity and contributive capacity. With this system, we analyzed the spatial-temporal variation of ecosystem health in Hexi Corridor and its relationship with climate change from 2000 to 2020 by utilizing the bivariate Moran's index. Results showed that the ecosystem health index in the Hexi Corridor improved by 2.5% during 2000-2020. The central oasis area and the southeastern mountainous area showed significant improvement in ecological health, while the northern desert area and some localized regions experienced degradation. During the study period, the overall health status of the Hexi Corridor's ecosystem remained at a moderate level, with consistent trend across various dimensions that initially declined before subsequently rising. There was a significant spatial positive correlation between climate change and ecosystem health. In the arid and low-precipitation condition of the Hexi Corridor, increased average annual precipitation and elevated average annual temperature contributed positively to ecosystem health, which was the key determinants of regional ecosystem health. Finally, we proposed corresponding strategies for enhancing ecosystem health levels in the southern Qilian Mountain area, the central oasis areas, and the nor-thern desert areas.

A workshop titled "Using Sentinel Species Data to Address the Potential Human Health Effects of Chemicals in the Environment," sponsored by the U.S. Army Center for Environmental Health Research, the National Center for Environmental Assessment of the EPA, and the Agency for Toxic Substances and Disease Registry, was held to consider the use of sentinel and surrogate animal species data for evaluating the potential human health effects of chemicals in the environment. The workshop took a broad view of the sentinel species concept, and included mammalian and nonmammalian species, companion animals, food animals, fish, amphibians, and other wildlife. Sentinel species data included observations of wild animals in field situations as well as experimental animal data. Workshop participants identified potential applications for sentinel species data derived from monitoring programs or serendipitous observations and explored the potential use of such information in human health hazard and risk assessments and for evaluating causes or mechanisms of effect. Although it is unlikely that sentinel species data will be used as the sole determinative factor in evaluating human health concerns, such data can be useful as for additional weight of evidence in a risk assessment, for providing early warning of situations requiring further study, or for monitoring the course of remedial activities. Attention was given to the factors impeding the application of sentinel species approaches and their acceptance in the scientific and regulatory communities. Workshop participants identified a number of critical research needs and opportunities for interagency collaboration that could help advance the use of sentinel species approaches.

In his letter, Greek correctly emphasizes the importance of theoretical foundations for understanding experimental observations. Our proposed human-specific paradigm for medical research and drug discovery does indeed rest on a strong theoretical, as well as empirical, basis. Because of the longevity of the animal research paradigm, in medical studies it is often assumed that animal-based data are generally applicable to humans, overlooking the significance of the species barrier as described by Greek. It is crucial to be aware that rodents and humans diverged evolutionarily 65–85 million years ago (Kumar and Hedges 1998), allowing plenty of time for disparities to develop in structure and functionality at all levels of biological complexity. Thus, inherent differences between mouse and human genetic backgrounds, immune systems, and brain circuitry are limiting progress in understanding autism spectrum disorders (Muotri 2015). In Alzheimer’s disease research, too, underlying species variations in genetics, protein pathways, metabolism, pharmacology, and physiology are very challenging (Langley 2014). The theory that inter- and intraspecies disparities confound extrapolation from other animals to humans is illustrated in many medical research fields, including stroke, motor neuron disease, Huntington’s disease, asthma, sepsis, and inflammatory disorders (Langley 2014). Although improvements could be made to the experimental design and methodology of animal studies, they remain inevitably flawed by the “insuperable species barrier” (Van Dam and De Deyn 2011), and better prospects for progress are becoming available through advanced techniques applied to reliable human-specific models. Humans (and many diseases) are complex systems, so a systems biology framework will be vital to integrate human-specific data of different levels of biological complexity, and to enable a dynamic understanding of disease causes, pathophysiologies, and potential drug targets (Zou et al. 2013). Machine-based data mining that captures and represents scientific knowledge in a structured format is already contributing to the construction of human disease pathways and networks (Kodamullil et al. 2015). There are still challenges in handling “big data,” including improving the curation and means of visualizing and characterizing complex systems. The reliability of any model can be considered in terms of its validity. Face validity addresses phenomenological similarities between a model and a human disease, but superficial similarities do not reliably imply the same underlying mechanisms. Moreover, most animal models only recapitulate limited pathophysiological aspects of human conditions. Construct validity does ask whether the model reflects the etiology and underlying biology of the human disease. However, the development of transgenic animal models based on human disease pathways can only be attempted after a pathway is already known to be clinically significant. Emerging human- and disease-specific in vitro models (such as those derived from human induced pluripotent stem cells) potentially offer a way forward, by enabling the discovery and detailed study of new human pathways and drug targets. Predictive validity asks whether a model reliably predicts what happens in humans, especially the effects of therapeutic interventions. This is a key factor in translational science and an obvious weakness in many animal studies, as shown by an analysis of 76 highly cited articles on several different animal species, published in seven high-impact scientific journals, which found that only 37% of the studies accurately predicted human outcomes (Hackam and Redelmeier 2006). The scientific literature increasingly includes critical assessments of the validity of animal models, reflecting serious concerns about their reliability and predictive value for human outcomes (Akhtar 2015). Few animal models have been evaluated by systematic review and meta-analysis of their performance characteristics such as reproducibility, specificity, sensitivity, clinical relevance, or mechanistic basis, and those that have frequently have performed poorly (Pound and Bracken 2014). Recognition of the problems is the first, essential step to finding solutions. A wider understanding is needed, based on both theoretical and empirical foundations, of the failure of animal models in medical research and drug discovery, and the reasons for that failure. That recognition will help drive the development and implementation of a radically improved 21st-century research paradigm.

Spatiotemporal changes of ecosystem health and their driving mechanisms in alpine regions on the northeastern Tibetan Plateau

A variety of chemical compounds and complex effluents were evaluated for toxicity using a luminescent bacterial test, and the results were compared with those of the rainbow trout, Spirillum, and Daphnia static bioassays. Direct correlations of the results were difficult as these assays utilize organisms of different levels of biological complexity. The data, however, demonstrated that in the majority of cases the luminescent bacterial test sensitivity was comparable with that of the rainbow trout, Spirillum, and Daphnia bioassays; particularly for organic compounds and complex effluents. Furthermore, this test appears to be relatively inexpensive, rapid, and simple, requires small sample volumes, and generally provides good reproducibility. While the luminescent bacterial test has potential as a valuable tool for short-term toxicity testing of effluents and specialty chemicals, it may be a poor indicator of toxicity for wastewaters containing certain specific compounds (such as ammonia or cyanide). Moreover, the test alone cannot substitute for acute or sublethal hazard assessment. It is therefore recommended that the luminescent bacterial test be used in a battery of screening tests or to supplement other well-established toxicity bioassays.

Understanding wildlife responses to novel threats is vital in counteracting biodiversity loss. The emerging pathogen Batrachochytrium salamandrivorans (Bsal) causes dramatic declines in European salamander populations, and is considered an imminent threat to global amphibian biodiversity. However, real-life disease outcomes remain largely uncharacterized. We performed a multidisciplinary assessment of the longer-term impacts of Bsal on highly susceptible fire salamander (Salamandra salamandra) populations, by comparing four of the earliest known outbreak sites to uninfected sites. Based on large-scale monitoring efforts, we found population persistence in strongly reduced abundances to over a decade after Bsal invasion, but also the extinction of an initially small-sized population. In turn, we found that host responses varied, and Bsal detection remained low, within surviving populations. Demographic analyses indicated an ongoing scarcity of large reproductive adults with potential for recruitment failure, while spatial comparisons indicated a population remnant persisting within aberrant habitat. Additionally, we detected no early signs of severe genetic deterioration, yet nor of increased host resistance. Beyond offering additional context to Bsal-driven salamander declines, results highlight how the impacts of emerging hypervirulent pathogens can be unpredictable and vary across different levels of biological complexity, and how limited pathogen detectability after population declines may complicate surveillance efforts.

The toxicity of chemical pollutants in dynamic natural systems: The challenge of integrating environmental factors and biological complexity

Epithelial-mesenchymal transition (EMT) is a cellular differentiation process whereby epithelial cells lose epithelial features and acquire mesenchymal, fibroblast-like properties, leading to reduced cell-cell contacts and increased motility. EMT is a fundamental biological process required for normal embryonic development, but may be co-opted by malignant epithelial tumors to facilitate metastatic spread. A known driver of EMT is the TGF-β superfamily of growth factor ligands, which elicit receptor-mediated responses in cells, primarily via TGF-β/SMAD signaling pathways. In these pathways, receptor-mediated SMAD (R-SMAD) proteins serve as the primary downstream effector molecules, the activities of which are regulated through receptor-mediated phosphorylation. The magnitude and duration of ligand-induced receptor activation influences the level of SMAD phosphorylation, which in turn influences the magnitude of the downstream cellular response(s). In this study, we describe high-throughput methods to quantitatively evaluate the biochemical and cellular responses to TGF-β/SMAD pathway activation in a cellular model of TGF-β-induced EMT. Effects of pathway activation are examined at different levels of biological complexity (biochemical, cellular, and multicellular), using 2D and 3D (spheroid) models. Collectively, these approaches enable a comprehensive evaluation of TGF-β/SMAD pathway activation that is amenable to high-throughput analysis platforms. Citation Format: Antony W. Wood, Ernest Heimsath. Quantitative evaluation of biomarkers for TGF-β-induced epithelial-mesenchymal transition in biochemical, cellular, and 3D spheroid model systems [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 204.