Seasonal variations influence environmental factors such as ambient temperature, sunlight duration and the availability of food resources, leading many species to develop behavioral and physiological adaptations. The present study explores the effect of seasonality on locomotor activity, rest and sleep patterns in captive dromedaries. Six adult female dromedaries were studied during the four seasons. Non-invasive PSG recordings (EEG, EOG, EMG) and behavioral observations were made over 72-h periods per season for each animal. The photoperiod varied seasonally from approximately 12.4 h in spring, 14.2 h in the summer, 12.4 h in autumn and 10.1 h in winter. The results reveal a robust diurnal activity pattern in dromedaries, with activity mainly concentrated during the day and rest dominating at night. The duration of motor activity shortened between summer and winter (17.1 h vs. 11.6 h). Seasonal differences were observed in vigilance states. In winter, the percentage of wakefulness was lower (52. 9
The striped murrel (Channa striata) is a high-value food fish in Southeast Asia; however, captive breeding success has remained limited due to a lack of knowledge about its reproductive physiology. This study examined the impact of synthetic gonadotropin-releasing hormone analogue (sGnRHa) on the reproductive biology of females. Brooders (450–650 g) were administered sGnRHa at 0.4 mL/Kg for male and 0.6 mL/Kg for female brooders (n = 18) and 0.9
Reptiles rely on behavioural thermoregulation to maintain optimal body temperature (Tb), essential for many physiological functions. However, thermal biology remains poorly studied in many snake species, including the Caspian whipsnake (Dolichophis caspius, Gmelin, 1789). This study examined the thermal biology of the Caspian whipsnake under natural and laboratory conditions. In the field, we investigated the influence of sex, age category, season, time of day, air temperature, detection status, feeding status, and shedding phase on Tb. Under controlled conditions, we assessed preferred Tb variation and its relationship to active thermoregulation. In the field, Tb was significantly affected by sex, season, time of day, air temperature, feeding status, and shedding phase, but not age category, body size or detection status. Males had lower Tb than females and snakes with food in their stomachs exhibited higher Tb. Tb increased from March to June and from morning to afternoon, and air temperature had a positive effect on Tb. In the laboratory, mean Tb (24.5 ± 4.9 °C) was lower than in the field (26.9 ± 5.2 °C) and was significantly associated with body posture and terrarium part, indicating active behavioural thermoregulation. In the laboratory, males had lower Tb than females, and juveniles had lower Tb than adults. The lower thermal preference suggests a cooler thermal niche than many colubrids, potentially increasing their susceptibility to climate warming. However, the broad Tb variation and behavioural thermoregulation indicate some flexibility in responding to environmental changes. These findings highlight the role of behavioural thermoregulation in snake thermal responses to environmental variation.
Mytilus galloprovincialis is a sessile, facultative anaerobic mussel inhabiting intertidal zones, where it experiences daily fluctuations in oxygen, temperature, and food availability. These environmental fluctuations require coordinated shifts in metabolism and cellular processes such as the cell cycle. As growth in mussels is environmentally driven, understanding how external perturbations modulate cell-cycle regulation is essential. Despite conserved cell-cycle machinery across eukaryotes, its dynamics in facultative anaerobic marine invertebrates remain largely unexplored. Mussels switch between aerobic (high-tide submergence) and anaerobic (low-tide emergence) respiration over tidal fluctuations. We hypothesized that cell-cycle gene expression (cyclins) is synchronized with tidal cues, peaking during anaerobic metabolism (low tide) in control-acclimated mussels to avoid DNA damage from oxidative stress during aerobic metabolism. Alternatively, peak expression would occur during submergence after experiencing acute heat stress in air to avoid higher risk of DNA damage by aerial heat compared to damage by oxidative stress in cool water. We also predicted higher cyclin transcript abundance in heat-stressed mussels compared to control mussels. To test these inferences, we exposed mussels to simulated tidal conditions and measured gene expression of cyclins and stress markers. We performed an RNA/DNA ratio assay as a proxy for short-term growth. As predicted, acute heat-stressed mussels exhibited significantly elevated cyclin transcript abundance compared to control mussels. Unexpectedly, cyclin D and E transcripts were upregulated during low tide in the heat-stressed mussels, while peak cyclin B expression was delayed until post-stress resubmergence. Furthermore, we did not observe significant changes in RNA/DNA ratio across the treatments. Our findings demonstrate that external environmental cues can modulate the timing and magnitude of cell-cycle gene expression in M. galloprovincialis, advancing our understanding of growth regulation in facultative anaerobes. We also assessed the potential of cyclin gene expression regulation through RNA secondary structure (RNA thermometer).
Environmental proliferation of Microcystis aeruginosa poses a significant toxicological threat to farmed fish. This study investigated the intestinal toxicity of M. aeruginosa in grass carp using integrated histological, biochemical, molecular, microbiome, and metabolomic analyses. Histological observations revealed epithelial disorganization, villus shortening, crypt hyperplasia, and goblet cell depletion. High-throughput sequencing showed stable microbial α-diversity but pronounced community restructuring, characterized by enrichment of Actinobacteria and Epsilonbacteraeota and emergence of key taxa including Prevotellaceae_UCG.001, Escherichia–Shigella, Enterobacter, and Vibrio. Oxidative imbalance was evident, accompanied by increased lipid peroxidation and reduced digestive capacity. Intestinal inflammation, epithelial barrier disruption, and mitochondrial-dependent apoptosis were markedly induced. Metabolomic profiling demonstrated clear exposure-associated metabolic reprogramming with coordinated alterations in amino acid and lipid metabolism, including activation of lysine degradation and fatty acid biosynthesis and suppression of arginine-related pathways and mTOR signaling. Microbiota–metabolite correlation analysis revealed coordinated associations between bacterial taxa and metabolic signatures. In vitro assays further confirmed reduced cell viability and antioxidant capacity in primary intestinal cells. Collectively, M. aeruginosa disrupts intestinal homeostasis in grass carp through integrated oxidative, inflammatory, apoptotic, and microbiota-associated metabolic pathways.
