Stresses

16 pages, 2787 KiB

Open AccessArticle

Interactive Effects of Ionophore Antibiotic Monensin and Polystyrene Microplastics on the Growth and Physiology of Microcystis aeruginosa

by Behen Manawadu, Mudalige Don Hiranya Jayasanka Senavirathna and Takeshi Fujino

Stresses 2025, 5(3), 43; https://doi.org/10.3390/stresses5030043 - 1 Jul 2025

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Abstract

This study was conducted to examine the combined effects of monensin (MS) and 3 µm polystyrene microplastics (PEMPs) on the growth and stress-associated physiological responses of Microcystis aeruginosa under controlled laboratory conditions [temperature: 20 ± 1 °C, lighting: (30 ± 4) µmol m⁻² s⁻¹ (12 h:12 h light–dark photoperiod), growth medium: BG-11]. The experiments included MS concentrations of 0, 50, 250, and 500 µg/L and PEMPs concentrations of 0.25, 1.25, and 6 mg/L. Measurements included optical density (OD₇₃₀), chlorophyll ‘a’, cellular protein content, oxidative stress, and the activities of catalase (CAT) and guaiacol peroxidase (GPX). M. aeruginosa exhibited a significant increase in growth on day 7 at elevated MS concentrations across all PEMP levels. Similarly, MS and PEMP treatments had a significant interactive effect on cellular protein content on day 7. However, their combined effect on chlorophyll ‘a’ production was not significant. Oxidative stress measurements showed a dose-dependent decrease with increasing MS concentrations under PEMP administrations. Enzyme activity assays indicated that CAT activity increased while GPX activity decreased with higher MS concentrations. The results imply that co-contamination of PEMPs and MS has a significant impact on the growth and stress physiology of M. aeruginosa in aquatic ecosystems. Full article

(This article belongs to the Section Plant and Photoautotrophic Stresses)

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18 pages, 653 KiB

Open AccessArticle

Physiological Trade-Offs Under Thermal Variability in the Giant Lion’s Paw Scallop (Nodipecten subnodosus): Metabolic Compensation and Oxidative Stress

by Natalia G. Joachin-Mejia, Ilie S. Racotta, Diana P. Carreño-León, Sergio A. Ulaje and Salvador E. Lluch-Cota

Stresses 2025, 5(3), 42; https://doi.org/10.3390/stresses5030042 - 1 Jul 2025

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Abstract

Understanding how thermal variability affects marine ectotherms is essential for predicting species resilience under climate change. We investigated the physiological responses of juvenile Nodipecten subnodosus (lion’s paw scallop), offspring of two genetically distinct populations (Bahía de Los Ángeles and Laguna Ojo de Liebre), reared under common garden conditions and exposed to three temperature regimes: constant, regular oscillation, and stochastic variability. After 15 days of exposure, scallops underwent an acute hyperthermia challenge. We measured metabolic rates, scope for growth (SFG), tissue biochemical composition, and oxidative stress markers (SOD, CAT, GPx, TBARS). No significant differences were detected between populations for most traits, suggesting that phenotypic plasticity predominates over evolutionary divergence in thermal responses. However, the temperature regime significantly influenced metabolic, biochemical and oxidative stress markers, indicating that scallops in variable conditions compensated through improved energy balance and food assimilation but also showed higher oxidative stress compared to the constant regime. Following acute hyperthermic exposure, energy demand escalated, compensatory mechanisms were impaired, and scallops attained a state of physiological maintenance and survival under stress, irrespective of their population or prior thermal regime exposure. Full article

(This article belongs to the Collection Feature Papers in Human and Animal Stresses)

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15 pages, 1673 KiB

Open AccessArticle

miRNA Markers of Stress Exposure in Pregnancy in African American Communities

by Brianna V. Becher, Nick I. Ahmed, Candice King, Jahnavi Godavarthi, Clark Bloomer, Rocio Rivera, Zohreh Talebizadeh, Jean Goodman, Rebecca Bond, Kennadie Long, Katelyn Weber, Malori Chrisman, Samantha Hunter, Nicole Takahashi and David Q. Beversdorf

Stresses 2025, 5(3), 41; https://doi.org/10.3390/stresses5030041 - 1 Jul 2025

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Abstract

While genetic mechanisms in neurodevelopmental disorders are well studied, the mechanisms of environmental factors such as prenatal stress are less understood. Our lab previously characterized miRNA changes associated with stress during pregnancy in mouse brains and in maternal blood from mothers of children with ASD and indicated that prenatal stress can be linked to epigenetic markers. These miRNAs could be used as discovery biomarkers for stress exposure, as well as predictors of neurodevelopmental outcomes. In this pilot study, we gathered saliva samples and stress survey questionnaires from 83 pregnant African American women (ages 18–40) at the time of their ultrasound performed at 20 weeks. miRNA analysis was performed on the 10 highest- and 10 lowest-stress subjects. Out of 6631 miRNAs examined, 34 had significant differential expression, with 5 being upregulated and 29 downregulated in the high-stress group. Predicted targets of differentially expressed miRNAs revealed significant enrichment in neurodevelopmental pathways, including forebrain development, sensory system development, and neuronal growth regulation. This may suggest the potential developmental salience of these miRNA profiles. Future research will examine the neurodevelopmental outcomes of these pregnancies to determine the predictive potential of these miRNAs. This may help identify individuals at greatest risk after stress exposure during pregnancy. Full article

(This article belongs to the Collection Feature Papers in Human and Animal Stresses)

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Stresses, Volume 5, Issue 3 (September 2025) – 3 articles

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