Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology最新文献

Understanding how environmental stressors influence memory formation is essential for evaluating the ecological and toxicological impacts of pollution on animal behavior. Using Lymnaea stagnalis snails collected from a pollutant-exposed freshwater creek in Canada, we investigated how distinct stressors affect learning and memory abilities and their underlying molecular mechanisms. In one procedure, pairing an appetitive cue with a predator-mimicking mechanical stressor (shell clip) revealed intra-strain variability in memory formation: only a subset of snails formed aversive memory, evidenced by reduced feeding upon cue re-exposure. This behavioral divergence correlated with increased expression of oxidative stress markers and plasticity-related genes in the central nervous system. In contrast, pairing the same cue with acute heat shock, known to induce a sickness-like state, resulted in long-term memory formation only in snails showing upregulation of cellular stress, immune-related, and neuroplasticity genes. Thus, both the nature of the stressor and individual physiological state shape memory outcomes, with Lymnaea engaging stressor-specific molecular programs to support learning. Importantly, this work positions Lymnaea as a valuable sentinel species in behavioral ecotoxicology. The transcriptional markers identified, such as LymHSP70, LymTLR4, and LymP2X, may serve as sensitive indicators of learning and memory disruption by environmental contaminants. By integrating behavioral and gene expression analyses, this study offers a promising framework for investigating how natural and anthropogenic stressors affect cognition, with broad applications for environmental monitoring, toxicology, and conservation biology.

This study examined the effects of mint (Mentha piperita L.) leaf extract (MLE) on the growth, immune responses, antioxidant activity, and hemolymph biochemical parameters in green tiger shrimp (Penaeus semisulcatus) under standard water chemistry and ammonia stress conditions. Four dietary treatments were established: a control and three MLE concentrations (0.5, 1, and 2 g/kg diet). A total of 240 shrimp (initial weight 9.22 ± 0.97 g) were distributed into 12 tanks and fed for eight weeks before ammonia challenge. The results indicated that MLE supplementation did not significantly affect growth performance. Phenoloxidase (PO) activity decreased at the MLE2 level, while lysozyme (Lys) activity increased in both the MLE1 and MLE2 groups compared to control. Superoxide dismutase (SOD) activity was significantly elevated in the MLE2 group, whereas total antioxidant capacity (TAOC), glutathione peroxidase (GPX) and catalase (CAT) activities remained unchanged. The activities of acid phosphatase (ACP), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) all decreased in at least one MLE exposure group. Lactate dehydrogenase (LDH) activity increased in all MLE groups. After ammonia stress, antioxidant parameters increased in all MLE groups, except for CAT. Activities of ALT and AST were significantly increased in all MLE-supplemented groups. However, LDH and ALP activities were significantly elevated only in MLE1 and MLE2 groups, while ACP activity showed a significant increase solely in MLE1 group compared to control. These results suggest MLE acts primarily as an antioxidant stimulant in P. semisulcatus.

The identification of the first nuclear receptors (NRs) several decades ago opened up new avenues for the study of a wide range of physiological processes. Although vertebrate receptors were first to be identified, studies in invertebrates were integral to establishing their transcriptional roles. The determination of 3D structures as well as advances in transcriptomic and proteomic techniques, have also been important in enhancing understanding of NR functions. Structural models and docking studies are the first step towards the discovery of invertebrate NR ligands as well as to understanding the binding properties of these NRs. The objective of this work is to review the NR ligands of invertebrates, specifically retinoids, steroids, fatty acids and phospholipids, bile acids and vitamin D, tyrosine derivatives and porphyrins. Non-typical NR ligands such as metals and gases are also described. We also address structural and evolutionary aspects. Exploring the ligands of invertebrate nuclear receptors, whether endogenous or exogenous, is a strategy that enables us to understand the role these receptors play in the biology of these organisms, as well as to uncover metabolic pathways that are not yet fully understood.