Search Results (343)

Freezing is the most commonly used preservation method for aquatic products, but the freeze–thaw cycle leads to the formation and growth of ice crystals, which seriously affects the quality of fish. This study evaluated the effect of dietary supplementation with theabrownins (TBs) on the quality attributes of grass carp (Ctenopharyngodon idella) muscle following freeze–thaw treatment. We examined changes in textural properties, ice crystal morphology and metabolomic profiles in response to TBs inclusion in feed. The results indicated that feeding TBs at 0.02% and 0.06% levels significantly improved the chewiness and cohesiveness of grass carp muscle. Histological analysis revealed that TB-containing feed effectively inhibited ice crystal growth, leading to smaller and more uniform ice crystals, thereby mitigating structural damage to muscle tissue. Metabolomic analysis identified distinct metabolite profile differences between the treatment groups and the control group, with both LTB (0.02% TBs) and HTB (0.06% TBs) groups showing significant upregulation of esters and aromatic compounds compared to the control group. The present study demonstrates that TBs, as a natural feed additive, can enhance the freeze–thaw tolerance of grass carp muscle by modulating ice crystal formation and influencing muscle metabolism. This study provides important insights and practical implications for developing novel strategies to improve the quality of frozen aquatic products. Full article

Acid mine drainage (AMD) and acid-generating mine wastes exhibit low pH, high sulfate levels, and complex multi-metal loads that strain conventional treatment. Thermoacidophilic red algae of the order Cyanidiales, particularly Galdieria sulphuraria (G. sulphuraria), have attracted interest as a biological option because they tolerate extreme acidity and elevated temperatures, grow under low light in mixotrophic or heterotrophic modes, and display rapid metal binding at the cell surface. This review synthesizes about two decades of peer-reviewed work to clarify how G. sulphuraria can be deployed as a practical module within mine water treatment trains. We examine the mechanisms of biosorption and bioaccumulation and show how they map onto two distinct configurations. Processed freeze-dried biomass functions as a regenerable sorbent for rare earth elements (REEs) and selected transition metals in packed beds with acid elution for recovery. Living cultures serve as polishing units for divalent metals and, when present, nutrients or dissolved organics under low light. We define realistic operating windows centered on pH 2–5 and temperatures of approximately 25–45 °C, and we identify matrix effects that govern success, including competition from ferric iron and aluminum, turbidity and fouling risks, ionic strength from sulfate, and suppression of REE uptake by phosphate in living systems. Building on laboratory studies, industrial leachate tests, and ecosystem observations, we propose placing G. sulphuraria upstream of bulk neutralization and outline reporting practices that enable cross-site comparison. The goal is an actionable framework that reduces reagent use and sludge generation while enabling metal capture and potential recovery of valuable metals from mine-influenced waters. Full article

Korla fragrant pear (Pyrus sinkiangensis), valued for its unique flavor, suffers from freezing damage in its native Xinjiang. Previous studies indicated a strong correlation between low-temperature stress and the expression of LEA genes, particularly PsLEA4. This study cloned PsLEA4 from P. sinkiangensis and overexpressed it in paper mulberry (Broussonetia papyrifera). The encoded 368-amino-acid protein is localized to the endoplasmic reticulum. Under −4 °C stress, the proline and soluble protein contents in the overexpressing lines increased to 1.21-fold and 1.36-fold, respectively, compared to the wild type, while relative water content (RWC) reached 1.58-fold. And catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) activities increased by 9%, 16%, and 38%, respectively. During overwintering, the transgenic line exhibited soluble protein content and RWC at 1.78-fold and 1.49-fold compared to those of the wild type, respectively. Malondialdehyde (MDA) and relative electrolyte leakage (REL) levels were only 66% and 63% of the wild type, while CAT and POD activities reached 1.87-fold, and SOD activity peaked at 2.49-fold. These adaptations were associated with improved cold tolerance and with bud break occurring 7–10 days earlier than in WT the following year. These findings could help to understand the molecular mechanisms of P. sinkiangensis for overwintering and provide new genetic resources to breed varieties of pear that can resist cold temperatures. Full article

Extremotolerant fungi inhabit environments with multiple overlapping stressors, yet most studies examine stresses individually. We tested whether preconditioning with salt, cold, or both improves survival after desiccation and freezing, and whether combined salinity and temperature effects on growth are additive or synergistic. We studied Aureobasidium pullulans, Aureobasidium subglaciale, Aureobasidium melanogenum, and Hortaea werneckii (haploid and diploid). All preconditioning treatments significantly increased long-term desiccation survival in A. pullulans, reflecting its generalist capacity to activate cross-protective responses. H. werneckii displayed smaller improvements, consistent with a specialist strategy. Freezing survival without cryoprotectants remained ~100% in both species, indicating high intrinsic tolerance. Growth analyses revealed synergistic effects of salinity and temperature in Aureobasidium spp. Species differed in salinity sensitivity (A. melanogenum > A. pullulans > A. subglaciale) and thermal preferences. A. melanogenum and A. pullulans grew faster at higher temperatures, while A. subglaciale showed the opposite trend. In H. werneckii, salinity governed growth. Haploids slowed as salinity increased, while the diploid remained unaffected. This is the first confirmation of the long-standing suggestion that hybrid diploid genomes of many H. werneckii are an adaptation to osmotic stress. These findings illustrate two pathways to extremotolerance: inducible flexibility in Aureobasidium versus constitutive halotolerance in H. werneckii. Full article

During their natural growth, plants encounter adverse environmental conditions, such as chilling injury, freezing injury, drought, and salt damage, collectively known as abiotic stresses. Several studies have shown that WRKY proteins regulate various abiotic stress responses and plant developmental processes. However, researchers have rarely investigated WRKY genes associated with the stress response in apples. Within this research, Malus baccata (L.) Borkh as the experimental material. We isolated and cloned MbWRKY63 and investigated its function in low-temperature stress tolerance. Subcellular localization analysis shows that MbWRKY63 localizes to the cell nucleus. Tissue-specific expression analysis revealed that MbWRKY63 is relatively highly expressed in the young leaves and root tissues of apples. Under low-temperature treatment at 4 °C, Arabidopsis thaliana plants that overexpressed MbWRKY63 showed greater cold stress resistance than the wild type (WT) and the empty vector (UL) control. In transgenic plants, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were significantly enhanced; meanwhile, the contents of proline, malondialdehyde (MDA), and chlorophyll also changed significantly. In addition, by regulating the expression levels of AtKIN1, AtCBF1, AtCBF2, AtCBF3, AtCOR47, and AtCOR15a, MbWRKY63 enhanced the low-temperature stress tolerance in transgenic Arabidopsis. The results suggest that MbWRKY63 in apples may be involved in the response to low-temperature stress, laying a foundation for understanding the role of WRKY transcription factors (TFs) in abiotic stress responses. Full article

Sperm cryo-tolerance resulted in significant variations in post-thaw semen quality among breeds and individual boars. In the present study, semen samples from thirty-seven large white boars were cryopreserved to select individuals with strong and weak freezing tolerance according to their post-thaw sperm quality. Comparative TMT-based quantitative proteomic analysis between the two groups identified 22 significantly differentially expressed proteins. NT5C1B and ADA, the significantly downregulated proteins in the semen of the low cryo-tolerance group, were supplemented in the semen samples with lower cryo-tolerance. Supplementation with 1 µg/mL of NT5C1B dramatically (p < 0.05) improved kinematic parameters and structural integrity. In comparison with the control group, mitochondrial activity and antioxidant capacity were significantly enhanced in post-thaw sperm. In vitro fertilization assays revealed that the NT5C1B-treated group also has notably (p < 0.05) high sperm penetration and embryonic cleavage rates. ADA supplementation did not exhibit obvious freezing tolerance effects. NT5C1B can be a potential key functional protein to enhance the quality and cryo-tolerance during cryopreservation. Specifically, supplementation with 1 µg/mL NT5C1B significantly improved post-thaw motility, structural integrity, mitochondrial activity, and antioxidant capacity and ultimately enhanced the sperm penetration rate and embryonic cleavage rate in cryo-sensitive sperm, confirming its role as a functional protector during cryopreservation. Full article

Plants such as winter crops are able to acclimate to low temperatures through complex physiological and biochemical modifications that enhance their frost tolerance. Cold acclimation involves changes in, e.g., photosynthetic efficiency, carbohydrate metabolism, the accumulation of osmoprotectants, the remodelling of membrane lipid composition, and the activation of the antioxidant system. Now, due to ongoing global climate change, temperature fluctuations have become more frequent, particularly during the autumn–winter period. Episodes of warm breaks (mainly above 9 °C) during winter disrupt the cold acclimation process and induce deacclimation, leading to a decrease in frost tolerance and a partial reversal of cold-induced metabolic adjustments. However, deacclimation is not just the reversal of acclimation, as evidenced by distinct responses in metabolites and hormones. Moreover, plants are able to regain lost freezing tolerance through reacclimation upon re-exposure to low temperatures. The article aimed to summarize the current knowledge on the basics underlying cold acclimation, deacclimation, and reacclimation. An explanation of these processes is crucial for protecting winter crop plants under the increasing frequency of variable temperatures during their growth. Full article

The red-haired bark beetle (RHB), Hylurgus ligniperda (Fabricius, 1787) (Coleoptera: Curculionidae: Scolytinae), is a globally distributed quarantine pest, making effective management of infested wood essential. This study developed an integrated control system to achieve closed-loop management under various environmental and wood conditions. RHB eggs were the most fumigation-tolerant stage. Although sulfuryl fluoride (SF) showed higher potency, aluminum phosphide (AP) provided deeper penetration into wood (AP: 29.5% vs. SF: 12.6%). Both fumigants effectively reached all logs in the stacks. Fumigation efficacy was highest at moderate temperatures (18–22 °C) and lower wood moisture levels. In addition to chemical methods, thermal treatments were evaluated: heating to 60–65 °C achieved complete mortality, while effective freezing control required temperatures of −30 °C. For bark and chip debris generated during processing, beta-cypermethrin fumigation effectively eliminated residual pests. Our results confirm that both AP and SF are suitable for disinfecting infested Pinus thunbergii wood, that extreme temperatures can reduce dispersal risks, and that beta-cypermethrin is effective in the downgraded utilization of wood byproducts. This work provides a comprehensive and practical framework for controlling the spread of this invasive pest. Full article

The freshwater drum (Aplodinotus grunniens) is a promising aquaculture species due to its strong environmental adaptability, tolerance to low temperatures, rapid growth rate, high nutritional value, high-quality texture (garlic-clove-shaped flesh), and absence of intermuscular bones. Nevertheless, processing technologies related to freshwater drum remain largely unexplored. Salting pretreatment serves as a viable strategy for enhancing the quality attributes of frozen fish products. This study investigated the effects of different sodium chloride (NaCl) pickling concentrations (0.25, 1, and 3 mol/L) on the physicochemical properties and quality attributes of frozen–thawed freshwater drum (Aplodinotus grunniens). Results indicated that elevated NaCl concentrations (1–3 mol/L) significantly (p < 0.05) shortened the transit time through the maximum ice crystal formation zone during freezing, effectively mitigating structural damage to myofibrillar networks. As the NaCl concentration increased from 0 to 3 mol/L, the water content decreased from 71.26 ± 0.22% to 68.64 ± 0.50%, while the salt content increased from 0.31 ± 0.01% to 8.46 ± 0.12%. Pickling pretreatment markedly enhanced water-holding capacity and improved texture profiles, including hardness, springiness, gumminess, and chewiness. Histological analysis revealed preserved myofibril integrity in high-salt-treated samples, supported by reduced fluorescence intensity of myofibrillar proteins, indicating mitigated freeze-induced denaturation. Low-field NMR confirmed salt-induced redistribution of water states, with decreased free water proportion. Our results identify that pretreatment with NaCl at concentrations ≥ 1 mol/L is an effective strategy to preserve the post-thaw quality. Due to 3 mol/L NaCl resulting in a relatively high salt content, 1 mol/L NaCl pretreatment is more suitable for maintaining the quality of freeze–thawed freshwater drums. Full article

Cold-adapted species display remarkable genomic resilience under prolonged freezing and thawing cycles that would be lethal to most organisms. This review synthesizes current knowledge on the molecular mechanisms of DNA damage response (DDR) and epigenetic regulation that collectively safeguard genome integrity in these organisms. We highlight key DNA repair pathways, including base excision repair (BER), nucleotide excision repair (NER), homologous recombination (HR), and non-homologous end joining (NHEJ), that are activated during freeze–thaw stress to repair oxidative and strand break damage. Epigenetic regulators such as DNA methyltransferases (DNMTs), histone methyltransferases, and histone deacetylases (HDACs) dynamically remodel chromatin and modulate DDR signaling, facilitating efficient repair and transcriptional reprogramming during recovery. Comparative evidence from freeze-tolerant vertebrates, hibernating mammals, and polar fish underscores the conservation of these adaptive pathways across taxa. Integrating these insights provides a molecular network perspective (MNP) linking DDR and epigenetic mechanisms to environmental resilience, with potential applications in crop improvement and biotechnological adaptation strategies for extreme environments. Full article

Real-time sweat pH monitoring offers a non-invasive window into metabolic status, disease progression, and wound healing. However, current wearable pH sensors struggle to balance high electrochemical sensitivity with mechanical compliance. Here we report a stretchable fiber-integrated pH electrode based on a polyaniline-phytic acid-polyvinyl alcohol (PANI-PA-PVA) hydrogel, which combines mechanical elasticity with enhanced electrochemical performance for continuous sweat sensing. Freeze–thaw crosslinking of the hydrogel forms a porous interpenetrating network, facilitating rapid proton transport and stable coupling with dry-spun elastic gold fibers. This wearable device exhibits an ultra-Nernstian sensitivity of 68.8 mV pH⁻¹, ultra-fast equilibrium (<10 s within the sweat-relevant acidic window), long-term drift of 0.0925 mV h⁻¹, and high mechanical tolerance (gel stretch recovery up to 165%). The sensor maintains consistent pH responses under bending and tensile strains, yielding sweat pH measurements at the skin surface during running that closely match commercial pH meters (sweat pH range measured in test subjects: 4.2–5.0). We further demonstrate real-time wireless readouts by integrating elastic gold and Ag/AgCl fibers into a three-electrode textile structure. This PANI-PA-PVA hydrogel strategy provides a scalable material platform for robust, high-performance wearable ion sensing and skin diagnostics. Full article

The ability of Ribes species to survive the fluctuating winter and early spring conditions, relies on the regulation of transcription factors (TFs) and other key genes involved in the abiotic stress response. In this study, we developed specific primers for 33 stress-responsive genes, which may facilitate future functional studies in Ribes and other less-characterized lineages within the Saxifragales order. These genes were selected based on a comparative transcriptomic analysis of R. nigrum cv. Aldoniai and are known to function in cold acclimation and stress signaling pathways. We analyzed expression profiles of these 33 genes in R. aureum, R. hudsonianum, and R. nigrum microshoot cultures exposed to controlled cold stress, deacclimation and reacclimation treatments. Our results revealed species-specific genetic responses across acclimation cycles of varying durations (24–96 h). Cold stress induces molecular changes in three Ribes spp.; however, deacclimation triggered by transient warming significantly reduced freezing tolerance in R. nigrum, had a moderate effect on R. hudsonianum, and minor impact on R. aureum. Gene expression profiling revealed distinct, species-specific regulatory patterns among species during different stress cycles, highlighting conserved and specific genes in acclimation mechanisms within the Ribes spp. These findings contribute to a deeper understanding of transcriptional regulation under acclimation cycles in currants and provide molecular tools that may support breeding strategies aimed at enhancing cold tolerance in Ribes crops amid increasing climate variability. Full article

Tiliacora triandra (Yanang) leaf contains polyphenols, flavonoids, and mucilage polysaccharides with antioxidant and prebiotic functions, making it a promising substrate for probiotic fermentation. This study aimed to optimize Yanang extraction and sterilization to preserve bioactive mucilage and support probiotic survivability during freeze-drying–based encapsulation, and evaluate antimicrobial activity against poultry pathogens. Yanang extract was prepared under different leaf processing conditions and used as a substrate for Pediococcus acidilactici V202, Lactiplantibacillus plantarum TISTR 926, Streptococcus thermophilus TISTR 894, Bacillus subtilis RP4-18, and Bacillus licheniformis 46-2. Fermentation at 37 °C for 24 h revealed that lactic acid bacteria (P. acidilactici V202, L. plantarum TISTR 926, S. thermophilus TISTR 894) reduced pH (<4.10, p < 0.001) while maintaining high viable counts (>8.67 log CFU/mL, p < 0.01), whereas Bacillus strains (B. subtilis RP4-18, B. licheniformis 46-2) retained a higher pH (>5.00) and lower viability (<8.50 log CFU/mL). Total soluble solids decreased across treatments, with the lowest observed for B. subtilis RP4-18 (1.97 °Brix, p = 0.007). Freeze-dried probiotics encapsulated in enzyme-extracted rice bran carriers had comparable physicochemical properties (p > 0.05), while compared with Bacillus strains (p < 0.01), lactic acid bacteria had superior tolerance to simulated gastrointestinal and thermal stress. Supernatant from Yanang extract inhibited B. cereus WU22001, S. aureus ATCC25923, Escherichia coli ATCC25922, and Salmonella typhimurium WU241001 (MIC/MBC 25–50% v/v). These results indicate that Yanang extract supports effective probiotic fermentation, and rice bran encapsulation enhances survivability and antimicrobial functionality for potential functional feed applications. Full article

Straw return is crucial for sustainable agriculture, but its efficiency is limited by low temperatures in cold regions, especially in saline-alkali soils. This study investigates the degradation process of maize straw and the response of soil properties and microbial communities during the winter low-temperature period in the alkaline farmland of Anda, China. A two-year field experiment with straw return (SR) and no return (NR) treatments was conducted. Straw degradation rates and structural changes (as observed via scanning electron microscope, SEM) were monitored. Soil physicochemical properties and enzyme activities were analyzed. Microbial community composition was characterized using 16S rRNA and ITS sequencing. The cumulative straw degradation rate over two years reached 94.81%, with 18.33% occurring in the first winter freeze–thaw period. Freeze–thaw cycles significantly damaged the straw structure, facilitating microbial colonization. Straw return significantly improved soil properties after winter, increasing field water capacity (3.45%), content of large aggregates (6.57%), available nutrients (P 38.17 mg/kg, K 191.93 mg/kg), and organic carbon fractions compared to NR. Microbial analysis revealed that low temperatures filtered the community, enriching cold-tolerant taxa like Pseudogymnoascus, Penicillium, and Pedobacter, which are crucial for lignocellulose decomposition under cold conditions. The winter period plays a significant role in initiating straw degradation in cold regions. Straw return mitigates the adverse effects of winter freezing on soil quality and promotes the development of a cold-adapted microbial consortium, thereby enhancing the sustainability of alkaline farmland ecosystems in Northeast China. Full article

Semen cryopreservation is a crucial technology for enhancing reproductive efficiency in livestock production; however, oxidative stress-induced sperm damage during the freeze–thaw process remains a significant challenge. In this study, metabolomics was used to analyze the differences in metabolites in semen from Qinchuan cattle with different freezing tolerance, and to screen out the candidate markers of sperm freezing tolerance. The metabolomics results indicate that a total of 264 differential metabolites were identified, and KEGG pathway annotation revealed that amino acid metabolism (15.07%) were prominently represented, and L-glutamine (L-Gln) showed a particularly high abundance in high freezability group (HFG) compared to the low freezability group (LFG). Further experiments demonstrated that L-glutamine supplementation significantly improved post-thaw sperm motility, plasma membrane integrity, and acrosomal integrity (p < 0.05). It also enhanced sperm antioxidant capacity by increasing the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT), while reducing malondialdehyde (MDA) content (p < 0.05). Additionally, L-Gln maintained mitochondrial function and energy homeostasis by elevating mitochondrial membrane potential (MMP) and promoting AMPK phosphorylation (p < 0.05). These results indicate that L-glutamine alleviates oxidative damage during cryopreservation and enhances semen freeze tolerance. Full article