Search Results (9,107)

The ecological impact of microplastic pollution in freshwater ecosystems has received growing scientific attention, although research on freshwater species remains limited compared to marine organisms. This study investigates the individual and combined toxicological impacts of polystyrene nanoparticles (PSNPs) and dibutyl phthalate (DBP) on hybrid snakehead (Channa maculata ♀ × Channa argus ♂), a commercially important freshwater fish. PSNPs inhibited growth, induced hepatic and intestinal lesions, and delayed ovarian development, co-exposure with DBP exacerbated these effects. qPCR analysis revealed significant up-regulation of inflammation-related genes in the liver but inhibitory effects in the intestines, indicating that PSNPs and DBP provoke immune modulation and systemic pro-inflammatory responses. Furthermore, PSNPs and DBP induced oxidative damage in the liver and intestines by affecting antioxidant enzyme activity. 16S rRNA sequencing revealed that PSNPs and DBP altered intestinal microbiota composition, particularly reducing Proteobacteria abundance. Correlation analyses indicated negative associations between the abundances of Proteobacteria and Firmicutes and antioxidant parameters (SOD and MDA), suggesting microbiota-mediated impacts on host metabolism and physiological health. These findings highlight the ecological threat of microplastics and phthalates in freshwater environments and underscore the need for targeted conservation strategies. Full article

Background: The escalating global salinization poses a significant threat to agricultural productivity, necessitating a thorough understanding of plant responses to high salinity. Pea sprouts (Pisum sativum), a nutrient-rich crop increasingly cultivated in salinized regions, serve as an ideal model for such investigations due to their rapid growth cycle and documented sensitivity to ionic stress. Methods: In order to understand the response of pea sprouts in physiological regulation, redox-metabolic adjustments, and transcriptome reprogramming under salt stress, we investigated the effects of high salt concentrations on the ascorbic acid–glutathione cycle, endogenous hormone levels, metabolite profiles, and gene expression patterns in it. Results: Our findings reveal early-phase antioxidant/hormonal adjustments, mid-phase metabolic shifts, and late-phase transcriptomic reprogramming of pea sprouts under salt conditions. In addition, a biphasic response in the ascorbic acid cycle was found, with initial increases in enzyme activities followed by a decline, suggesting a temporary enhancement of antioxidant defenses. Hormonal profiling indicated a significant increase in abscisic acid (ABA) and jasmonic acid (JA), paralleled by a decrease in indole acetic acid (IAA) and dihydrozeatin (DZ), underscoring the role of hormonal regulation in stress adaptation. Metabolomic analysis uncovered salt-induced perturbations in sugars, amino acids, and organic acids, reflecting the metabolic reconfiguration necessary for osmotic adjustment and energy reallocation. Transcriptomic analysis identified 6219 differentially expressed genes (DEGs), with a focus on photosynthesis, hormone signaling, and stress-responsive pathways, providing insights into the molecular underpinnings of salt tolerance. Conclusions: This comprehensive study offers novel insights into the complex mechanisms employed by pea sprouts to combat salinity stress, contributing to the understanding of plant salt tolerance and potentially guiding the development of salt-resistant crop varieties. Full article

Proteins that span cellular membranes represent around 30% of the proteome and over 50% of drug targets. A variety of synthetic and naturally-occurring small organic molecules interact with membrane proteins and up- and down-regulate protein function. The atomic details of these regulatory molecules offer important information about protein function and aid the discovery, refinement and optimization of new drugs. X-ray crystallography and cryo-electron microscopy (cryo-EM) are not always able to resolve the structures of small molecules in their physiological sites on membrane proteins, particularly if the molecules are unstable or are reactive enzyme substrates. Solid-state nuclear magnetic resonance (SSNMR) is a valuable technique for filling in missing details on the conformations, dynamics and binding environments of small molecules regulators of membrane proteins. SSNMR does not require diffracting crystals possessing long-range order and can be performed on proteins within their native membranes and with freeze-trapping to maintain sample stability. Here, work over the last two decades is described, in which SSNMR methods have been developed to report on interactions of the ATP substrate with the Na,K-ATPase (NKA), an ion-transporting enzyme that maintains cellular potential in all animals. It is shown how a combination of SSNMR measurements on membranous NKA preparations in the frozen and fluid states have provided unique information about the molecular conformation and local environment of ATP in the high-affinity nucleotide site. A combination of chemical shift analysis using density functional theory (DFT) calculations, dipolar coupling measurements using REDOR and measurements of the rates of proton spin diffusion is appraised collectively. The work described herein highlights the methods developed and challenges encountered, which have led to a detailed and unrivalled picture of ATP in its high-affinity binding site. Full article

Botryosphaeria dothidea (Moug. ex Fr.) Ces. & De Not. is a major pathogenic fungus causing stem canker in Idesia polycarpa, posing a significant threat to the growth and survival of its plantations. To elucidate the physiological and biochemical responses of the host under pathogenic stress, this study used two-year-old potted seedlings of I. polycarpa (provenance: ‘Emeishan No. 1’) and conducted artificial inoculation. Dynamic changes in physiological and biochemical indices at different disease stages were systematically monitored. The results revealed a distinct stage-specific response pattern: in the early infection stage, the activities of antioxidant enzymes (POD and SOD) increased rapidly, accompanied by significant elevations in osmotic regulators such as proline and soluble protein. In the mid-stage, malondialdehyde (MDA) content increased, while the levels of photosynthetic pigments—especially chlorophyll b and carotenoids—declined, indicating intensified oxidative damage. In the late stage, antioxidant capacity and osmotic adjustment weakened, and the photosynthetic system was continuously impaired. Correlation analysis further demonstrated significant synergistic relationships among antioxidant defense, membrane stability, osmotic regulation, and photosynthetic function. These findings enhance our understanding of the disease resistance mechanisms in I. polycarpa and provide a theoretical and practical reference for resistance evaluation and precise management of canker disease in woody species. Full article

Chronic hepatitis B virus (HBV) infection may influence extrahepatic systems, including endocrine and lipid regulation. In this cross-sectional study, 186 adults were stratified by HBV DNA status and viral load to examine thyroid function, systemic inflammation, and lipid metabolism, with further analyses by age and sex. Thyroid-stimulating hormone (TSH, a pituitary regulator of thyroid function) levels were significantly lower in HBsAg-positive individuals compared with controls; however, this association was attenuated after stratification by viral load, indicating that the relationship is not unequivocally independent of HBV DNA levels, as free thyroxine (FT4, the circulating thyroid hormone reflecting gland activity) levels remained stable. Lipid profiles displayed demographic-specific patterns: males with high viral load exhibited lower HDL cholesterol, whereas younger HBV-positive individuals showed higher LDL cholesterol. CRP levels were unaffected by HBV status or viral load, aligning with the absence of systemic inflammation in early or inactive disease stages. Age was a major determinant across biomarkers, with complex interactions involving sex and viral load. These findings indicate subtle but clinically relevant extrahepatic effects of HBV infection and underscore the need for personalized monitoring and longitudinal studies to clarify metabolic and cardiovascular implications. These subgroup trends should be interpreted with caution given the absence of BMI, liver enzyme, fibrosis, medication, and comorbidity data in this retrospective cohort. Full article

Tibetan sheep are an important livestock breed adapted to the extreme environment of the Qinghai–Tibet Plateau (QTP). Their energy metabolism and environmental adaptability are highly dependent on the rumen microbiome. However, systematic comparisons of the rumen microbiome, its functions, and the resistome between plateau-adapted breeds and lowland breeds remain insufficient. In this study, 6 Tibetan sheep (TS) and 6 Hu sheep (HS) were selected. All the selected sheep had a body weight of 34 kg (±0.5 kg) and an age of 1 year (±1 month) and were all managed under local traditional natural grazing (without supplementary feeding). Using metagenomics and metabolomics techniques, systematic comparative analysis was conducted on the differences in rumen microbial community structure, functions, resistome, and metabolites between the two breeds. Metagenomic analysis showed that at the phylum level, the abundance of Bacteroidetes in the rumen of TS was significantly higher than that in HS (p < 0.05); at the genus level, the abundance of Bacteroides in TS was also significantly higher (p < 0.05). Carbohydrate-active enzymes (CAZy) analysis indicated that the abundance of Glycosyltransferases (GTs) and Carbohydrate-Binding Modules (CBMs) in the rumen of TS were significantly upregulated (p < 0.05), while HS was rich in various Glycoside Hydrolases (GHs). Comprehensive Antibiotic Resistance Database (CARD) analysis revealed that more than 60% of the Antibiotic Resistance Genes (ARGs) in the rumen of HS were present at higher levels than those in TS. Metabolomics identified a large number of differential metabolites, among which metabolites such as 2E,6Z,8Z,12E-hexadecatetraenoic acid, Leukotriene F4, and Tenurin were significantly upregulated in the rumen of TS. Correlation analysis showed that rumen microbial flora and their metabolites jointly act to regulate rumen ARGs. Specifically, microorganisms including Firmicutes and Succiniclasticum had a significantly positive correlation with ARGs such as rpoB2 (p < 0.05), while differential metabolites like endomorphin-1 and Purothionin AII exhibited a significantly negative correlation with ARGs such as rpoB2 (p < 0.05). Therefore, compared with HS, the synergistic effect of the rumen microbial flora, their metabolites, and the resistome in TS is an important characteristic and strategy for their adaptation to the hypoxic environment of the QTP, and also contributes to the formation of their unique rumen resistome. Despite being reared in the same plateau environment, the rumen microbiome of HS still retains low-altitude characteristics, which are manifested as high GHs activity and high ARGs abundance. Full article

Allopregnanolone (allo) and isoallopregnanolone (isoallo) are neuroactive steroid epimers that differ in hydroxyl orientation at carbon three. Allo is a potent GABA-A receptor agonist, while isoallo acts as an antagonist, influencing brain function through their interconversion. Their metabolism varies across brain regions due to enzyme distribution, with AKR1C1–AKR1C3 active in the brain and AKR1C4 restricted to the liver. In rats, AKR1C9 (liver) and AKR1C14 (intestine) perform similar roles. Beyond AKR1Cs, HSD17Bs regulate steroid balance, with HSD17B6 active in the liver, thyroid, and lung, while HSD17B10, a mitochondrial enzyme, influences metabolism in high-energy tissues. Our current data obtained using the GC-MS/MS platform show that allo and isoallo in rats undergo significant metabolic conversion, suggesting a regulatory role in neurosteroid action. High allo levels following isoallo injection indicate brain interconversion, while isoallo clears more slowly from blood and undergoes extensive conjugation. Metabolite patterns differ between brain and plasma—allo injection leads to 5α-DHP and isoallo production, whereas isoallo treatment primarily yields allo. Human plasma contains mostly sulfate/glucuronided steroids (2.4–6% non-sulfate/glucuronided), whereas male rats exhibit much higher free steroid levels (29–56%), likely due to the absence of zona reticularis. These findings highlight tissue-specific enzymatic differences, which may impact neurosteroid regulation and CNS disorders. Full article

S-adenosylmethionine decarboxylase (AdoMetDC) is an essential enzyme in the polyamine biosynthesis pathway and plays a key role in the synthesis of the polyamines spermidine and spermine, polycationic alkylamines that are present in millimolar levels in mammalian cells. Polyamines are metabolic molecules that are involved in many fundamental processes, including regulation of protein and nucleic acid synthesis, stabilization of chromatin, differentiation, apoptosis, protection from oxidation, and regulation of ion channels. Multiple oncogenic pathways lead to dysregulation of polyamines, making polyamines a potential biomarker for cancer and polyamine biosynthesis a target for therapeutic intervention. This study uses multi-temperature crystallography to probe the structure and dynamics of AdoMetDC by collecting diffraction data at 100 K, 273 K, and 293 K. Differential loop behavior is observed across the collected datasets, with dramatic residue rearrangements. In the loop containing residues 20–28, the ambient temperature datasets show a large motion relative to the cryo structure. In a second loop containing residues 164–174, previous cryo structures do not report ordered positions. This loop is ordered in our 100 K structure, while assuming different conformations in the 273 K and 293 K data. These results further illustrate the usefulness of ambient data collection for understanding the structure and dynamics of proteins, especially in loop regions which are less restrained than protein cores. Full article

The liver orchestrates metabolic homeostasis through dynamic post-translational modifications. β-hydroxybutyrylation (Kbhb), a ketone body-driven modification, regulates epigenetics and metabolism in humans and mice but remains unexplored in livestock. Here, we characterize the porcine hepatic β-hydroxybutyrylome using high-resolution mass spectrometry, identifying 4982 Kbhb sites on 2122 proteins—the largest dataset to date. β-hydroxybutyrylation predominantly targets non-histone proteins (99.68%), with enrichment in fatty acid β-oxidation, TCA cycle, and oxidative phosphorylation pathways. Subcellular localization revealed cytoplasmic (38.1%), mitochondrial (18.1%), and nuclear (15.3%) dominance, reflecting BHB-CoA synthesis sites. Motif analysis identified conserved leucine, phenylalanine, and valine residues at modified lysines, suggesting enzyme-substrate specificity. β-hydroxybutyrate treatment elevated global Kbhb levels, increasing TCA intermediates (e.g., α-ketoglutarate, +9.56-fold) while reducing acetyl-CoA, indicating enhanced mitochondrial flux. Cross-species comparisons showed tissue-specific Kbhb distribution (nuclear in human cells vs. mitochondrial in mice), highlighting metabolic adaptations. This study establishes pigs as a model for Kbhb research, linking it to energy regulation and providing insights into metabolic reprogramming. Full article

Candida species commonly secrete aspartic peptidases (Saps), which are virulence factors involved in nutrient acquisition, colonization, tissue invasion, immune evasion and host adaptation. However, the regulation of Sap production remains poorly characterized in emerging, widespread and multidrug-resistant members of the Candida haemulonii clade (C. auris, C. haemulonii, C. haemulonii var. vulnera and C. duobushaemulonii). This study investigated the influence of temperature, pH and protein substrate on Sap production using bloodstream isolates of the C. haemulonii clade. Sap activity was initially assessed using the enzyme coefficient (Pz) in fungal cells grown on yeast carbon base (YCB) agar supplemented with bovine serum albumin (BSA) to determine optimal conditions for enzymatic production. C. auris and C. duobushaemulonii exhibited the highest Sap activity at 96 h, pH 4.0–5.0, and 37 °C, whereas C. haemulonii and C. haemulonii var. vulnera displayed more variable and isolate-dependent profiles. Sap production was markedly suppressed at pH 6.0. The addition of pepstatin A, an inhibitor of aspartic peptidases, abolished Sap activity and impaired fungal growth in a dose-dependent manner, confirming both the enzymatic identity and its critical role in nitrogen acquisition. Conversely, YCB supplemented with an inorganic nitrogen source (ammonium sulfate) supported fungal growth but did not induce Sap production. To explore substrate specificity, YCB was supplemented with a panel of proteins. Serum albumins (bovine and human) induced the highest Sap production, followed by globulin, gelatin, hemoglobin, collagen and immunoglobulin G, while elastin and mucin elicited the lowest Sap production. Isolate-specific preferences for protein substrates were observed. Finally, fluorometric assays using a Sap-specific fluorogenic peptide substrate confirmed the presence of Sap activity in cell-free supernatants, which was consistently and entirely blocked by pepstatin A. These findings highlight inter- and intraspecies variability in Sap regulation among C. haemulonii clade, stressing the critical roles of substrate availability, pH and temperature in shaping fungal adaptation to host environments. Full article

PYR/PYL (pyrroloquinoline quinone resistance/PYR1-like) are receptors for abscisic acid (ABA) in plants and play a crucial role in responses to abiotic stress. In this study, we identified 63 members of the StPYL gene family at the tetraploid whole-genome level in potatoes. We analyzed the physicochemical properties of these 63 StPYLs and constructed a phylogenetic tree using Arabidopsis thaliana and potato (Solanum tuberosum L.) cultivar ‘DM’ as the reference. By examining gene structure, conserved protein motifs, and collinearity, we found that StPYLs are highly conserved throughout evolution. The gene expression heat map under salt stress revealed that 57 StPYL genes are involved in the salt stress response. Among them, the expression level of StPYL9a-like changed significantly under salt stress. Through genetic transformation, we observed that overexpression of StPYL9a-like enhanced the growth and survival of potato plants under salt stress compared to the wild type. The contents of proline (Pro), superoxide dismutase (SOD), and chlorophyll in the leaves of overexpressing plants increased, while malondialdehyde (MDA) levels decreased. This suggests that StPYL9a-like positively regulates salt tolerance by affecting antioxidant enzyme activity and osmotic adjustment substances in potatoes. Subcellular localization demonstrated that StPYL9a-like is localized in the nucleus. This study provides a reference for the functional research of PYLs in potatoes, offers a basis for screening potato genes related to salt stress, and lays a foundation for developing salt-tolerant potato varieties. Full article

Background: Medicago ruthenica, a perennial legume forage valuable for ecological restoration and improved breeding, suffers significant harvest losses due to pod shattering. Pod shattering is a trait not only linked to not only pod ventral suture, but also pericarp properties. In this study, we aimed to (1) elucidate the role of pericarp in explosive pod shattering by comparing shattering-susceptible (SPD) and shattering-resistant (RPD) M. ruthenica genotypes, and (2) identify key regulatory genes and pathways underlying this mechanism. Methods: We conducted comparative analyses of pericarp anatomy and physiological traits (pericarp components such as water content, cellulose, hemicellulose, pectin, and lignin; and the activities of enzymes such as cellulose synthase A (CesA), phenylalanine ammonia-lyase (PAL), 4-coumarate: CoA ligase (4CL), cinnamyl alcohol dehydrogenase (CAD), and peroxidase (POD) in SPD and RPD pods). Transcriptome of pod pericarps identified differentially expressed genes (DEGs) for the selection of candidates functional genes. Promoter analysis was performed on candidate functional genes to identify specific regulated factors. The functional role of auxin signaling was validated through exogenous auxin application and the assessment of pod shattering rates and gene expression. Results: SPD pod pericarps exhibited significantly higher lignification of endocarp, lignin, cellulose, hemicellulose and pectin content, but lower water content than RPD. Principal component analysis identified that lignin contributes the highest loading value (0.727) contributor to pod shattering. The activities of five cell wall biosynthesis enzymes were higher in SPD pod pericarps than RPD. Transcriptome analysis identified more than 3419 DEGs in SPD pericarps. KEGG enrichment highlighted “phenylpropanoid biosynthesis” as the most significant pathway. A total of 57 lignin-biosynthesis-related DEGs were upregulated in SPD, including 15 PODs. Promoters of 11 POD genes contained MYB-binding motifs and 8 contained auxin-responsive elements, a total of 76 MYB transcription factors (mostly upregulated) and 9 auxin biosynthesis genes (mostly downregulated) were differentially expressed in SPD. Exogenous auxin application significantly reduced SPD pod shattering to 23.6% and concurrently downregulated PODs expression. Conclusions: This study establishes that enhanced lignification within the pericarp endocarp by the upregulation of lignin biosynthetic genes (particularly PODs), coupled with upregulation by MYB transcription factors and downregulation by auxin, is a core mechanism of explosive pod shattering in M. ruthenica. The identified DEGs, especially MYBs, PODs, and auxin pathway genes, provide gene information for breeding shattering-resistant M. ruthenica varieties through molecular design or marker-assisted selection. Full article

Water temperature stands as a crucial environmental element, exerting an impact on the survival and growth of organisms in aquaculture. Heat stress poses a significant threat to the survival and aquaculture of the Hong Kong oyster Magallana hongkongensis (also known as Crassostrea hongkongensis), yet the underlying physiological and molecular mechanisms remain poorly understood. This study investigated the effects of elevated temperatures (35 °C and 37 °C) on survival, DNA damage, antioxidant enzyme activities, and gene expression related to apoptosis, inflammation, and heat shock proteins (HSPs) in M. hongkongensis. The median lethal temperature (LT50) of M. hongkongensis was determined to be 37.09 °C, with significant mortality observed at 35 °C compared with the control (29 °C). Antioxidant enzyme activities (SOD, CAT, and GPx) and T-AOC were up-regulated initially but exhibited divergent patterns under prolonged stress, indicating a temperature-dependent threshold for oxidative defense. Comet assay results also showed that heat stress induced severe DNA damage in hemocytes. Moreover, heat stress significantly up-regulated mRNA expression of apoptosis-related genes (Caspase-2, Caspase-8, Bax, and P53), inflammatory genes (TNF, p38-MAPK, and AP-1), and HSP family members (Hsp70, Hsp90, Hsp27, and Hsp68). The expression peaks of these genes were generally earlier and more pronounced at 37 °C, reflecting intensified cellular damage and protective responses. Collectively, this study demonstrates that M. hongkongensis employs integrated antioxidant, apoptotic, inflammatory, and HSP-mediated mechanisms to counteract heat stress, but temperatures exceeding 35 °C disrupt these defenses, leading to survival impairment. These findings provide critical insights into the heat adaptation strategies of M. hongkongensis and serve as a scientific foundation for developing sustainable aquaculture practices to mitigate summer heat stress. Full article

Breast cancer is a common and chronic condition, and despite improvements in diagnosis, treatment, and prevention, the number of cases of breast cancer is rising annually. New therapeutic drugs that target specific checkpoints should be created to fight breast cancer. Mandragora autumnalis possesses substantial cultural value as a herb and is regarded as one of the most significant medicinal plants; however, little is known about its anticancerous biological activity and chemopreventive molecular pathways against the triple-negative breast cancer (MDA-MB-231) cell line. In this study, the antioxidant, anticancer, and underlying molecular mechanisms of the Mandragora autumnalis ethanolic leaves extract (MAE) were evaluated, and its phytochemical composition was determined. Results indicated that MAE diminished the viability of MDA-MB-231 cells in a concentration- and time-dependent manner. Although MAE exhibited 55% radical scavenging activity at higher concentrations in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, the attenuation of its cytotoxic effects in MDA-MB-231 cells with N-acetylcysteine (NAC) co-treatment suggests a potential role of oxidative stress. Additionally, MAE caused an increase in the tumor suppressor p53. Moreover, this extract caused a significant decrease in the expression of Ki-67 (a cellular proliferation marker), MMP-9 (matrix metalloproteinase-9, an enzyme involved in extracellular matrix degradation and metastasis), and STAT-3 (a transcription factor regulating cell growth and survival). Also, MAE altered cell cycle, cell migration, angiogenesis, invasion, aggregation, and adhesion to suppress cellular processes linked to metastasis. All of our research points to MAE’s potential to function as an anticancer agent and opens up new possibilities for the development of innovative triple-negative breast cancer treatments. Full article

Fusarium verticillioides, an important global pathogenic fungus, compromises crop quality and yield by infecting maize, sugarcane, and some Solanaceae, endangering food security through contaminated grains and cereals with the fumonisin B1 (FB1) toxin. While Con7 has been reported as a transcription factor involved in the sporulation and pathogenicity of some pathogenic fungi, the function of FvCon7 and its regulatory genes in F. verticillioides remains uncharacterized. Gene deletion mutants of ΔFvcon7 were constructed through homologous recombination, which exhibited defects in vegetative growth, survival, sporophore development, conidiation, conidial germination, and carbon metabolism. Carbon metabolism defects led to a significant accumulation of glycogen granules in hypha and lipid bodies in conidia. Additionally, ΔFvcon7 displayed impaired cell wall structure and integrity, along with an altered expression of genes encoding cell wall-degrading enzymes (such as chitinase), as detected by qRT-PCR. Moreover, Fvcon7 also plays a role in the pathogenicity of maize and sugarcane through different splicing, defective conidia, reduced survival viability, differential expression of secreted proteins, and deficiencies in antioxidant stress capacity. Furthermore, using yeast one-hybrid (Y1H) assays, FvCon7 was found for the first time to directly regulate the expression of FvFUMs by binding to the CCAAT box within the promoters of six key FvFUMs, thereby affecting FB1 production. Overall, FvCon7 functions as a global transcription factor regulating multiple phenotypes. This study provides a theoretical basis for elucidating the mechanism of transcription factor FvCon7 regulating toxin production and pathogenesis in F. verticillioides. Full article