Protein Metabolism Research Articles

Exposure to nanoplastics and nanomaterials either single and combined affects the gill-associated microbiome of the Antarctic soft-shelled clam Laternula elliptica

Nanoplastics and engineering nanomaterials (ENMs) are contaminants of emerging concern (CECs), increasingly being detected in the marine environment and recognized as a potential threat for marine biota at the global level including in polar areas. Few studies have assessed the impact of these anthropogenic nanoparticles in the microbiome of marine invertebrates, however combined exposure resembling natural scenarios has been overlooked. The present study aimed to evaluate the single and combined effects of polystyrene nanoparticles (PS NP) as proxy for nanoplastics and nanoscale titanium dioxide (nano-TiO2) on the prokaryotic communities associated with the gill tissue of the Antarctic soft-shell clam Laternula elliptica, a keystone species of marine benthos Wild-caught specimens were exposed to two environmentally relevant concentrations of carboxylated PS NP (PS–COOH NP, ∼62 nm size) and nano-TiO2 (Aeroxide P25, ∼25 nm) as 5 and 50 μg/L either single and combined for 96h in a semi-static condition.Our findings show a shift in microbiome composition in gills of soft-shell clams exposed to PS NP and nano-TiO2 either alone and in combination with a decrease in the relative abundance of OTU1 (Spirochaetaceae). In addition, an increase of gammaproteobacterial OTUs affiliated to MBAE14 and Methylophagaceae (involved in ammonia denitrification and associated with low-quality water), and the OTU Colwellia rossensis (previously recorded in polluted waters) was observed. Our results suggest that nanoplastics and nano-TiO2 alone and in combination induce alterations in microbiome composition by promoting the increase of negative taxa over beneficial ones in the gills of the Antarctic soft-shell clam. An increase of two low abundance OTUs in PS-COOH NPs exposed clams was also observed. A predicted gene function analysis revealed that sugar, lipid, protein and DNA metabolism were the main functions affected by either PS-COOH NP and nano-TiO2 exposure. The molecular functions involved in the altered affiliated OTUs are novel for nano-CEC exposures.

Transcriptomics and UHPLC-QQQ-MS analyses reveal the dysregulation of branched chain amino acids metabolism in renal fibrotic rats

The dysregulated levels of branched chain amino acids (BCAA) contribute to renal fibrosis in chronic kidney disease (CKD), yet specific analysis of BCAA contents and how they are regulated still remain unclear. It is therefore of great scientific interest to understand BCAA catabolism in CKD and develop a sensitive method for simultaneous determination of individual BCAA and their metabolites branched chain α-ketoacids (BCKA). In this work, the important role of BCAA metabolism that drives renal fibrosis in the process of CKD was first revealed by using transcriptomics. The key target genes controlling BCAA metabolism were then validated, that is, mRNA levels of BCKDHA and BCKDHB, the regulating rate-limiting enzymes during BCAA metabolism were abnormally reduced by quantitative PCR (qPCR), and a similar drop-off trend of protein expression of BCKDH, HIBCH and MCCC2 that are closely related to BCAA metabolism was also confirmed by western blotting. Furthermore, we established a novel strategy that simultaneously determines 6 individual BCAA and BCKA in serum and tissue. The method based on dansylhydrazine derivatization and ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry (UHPLC-QQQ-MS) achieved to simultaneously determine the contents of BCAA and BCKA, which is efficient and stable. Compared with normal rats, levels of BCAA including leucine, isoleucine and valine in serum and kidney of CKD rats was decreased, while BCKA including α-ketoisocaproic acid, α-ketomethylvaleric acid and α-ketoisovaleric acid was increased. Together, these findings revealed the abnormality of BCAA metabolism in driving the course of kidney fibrosis and CKD. Our current study sheds new light on changes in BCAA metabolism during CKD, and may facilitate development of drugs to treat CKD and renal fibrosis.

Investigation of the Alternations in the Muscle Quality of Swimming Crab (Ovalipes punctatus) during Cold-Chain Transportation Using Physicochemical and TMT-Based Quantitative Proteomic Analysis.

Physicochemical properties and protein alterations in Ovalipes punctatus during cold-chain transportation were examined via sensory scores, water-holding capacity (WHC), glucose (GLU) content, catalase (CAT) activity, urea nitrogen (UN) content, and tandem mass tag (TMT)-based proteomic analysis. The results revealed that sensory characteristics and texture of crab muscle deteriorated during transportation. Proteomic analysis revealed 442 and 470 different expressed proteins (DEPs) in crabs after 18 h (FC) and 36 h (DC) of transportation compared with live crabs (LC). Proteins related to muscle structure and amino acid metabolism significantly changed, as evidenced by the decreased WHC and sensory scores of crab muscle. Glycolysis, calcium signaling, and peroxisome pathways were upregulated in the FC/LC comparison, aligning with the changes in GLU content and CAT activity, revealing the stress response of energy metabolism and immune response in crabs during 0-18 h of transportation. The downregulated tricarboxylic acid (TCA) cycle and carcinogenesis-reactive oxygen species pathways were correlated with the decreasing trend in CAT activity, suggesting a gradual retardation in both energy and antioxidant metabolism in crabs during 18-36 h of transportation. Furthermore, the regulated purine nucleoside metabolic and nucleoside diphosphate-related processes, with the increasing changes in UN content, revealed the accumulation of metabolites in crabs.

An In-Depth Insight into the Profile, Mechanisms, Functions, and Transfer of Essential Amino Acids from Mulberry Leaves to Silkworm Bombyx mori L. Pupae and Fish.

The silkworm Bombyx mori, the second most varied group of insects, is a fascinating insect that belongs to the Lepidoptera species. We aimed to deepen our knowledge about the composition and significance of amino acids (AA) from the sericulture chain to fish. AAs are the most prevalent molecules throughout the growth process of silkworms. We described AAs classification, occurrence, metabolism, and functions. Online datasets revealed that the essential AAs (EAA) level in fish meal and silkworm pupae (SWP) is comparable. SWP have a high content of methionine and lysine, which are the principal limiting AAs in fish diets, indicating that SWP have nutritional potential to be added to fish diets. Additionally, an overview of the data analyzed displays that SWP have a higher protein efficiency ratio than fish meal, the classical protein-rich source (>1.19 times), and compared to soybean meal, the second-most preferred source of protein in aquaculture (>2.08 times), indicating that SWP can be considered effective for animal feeding. In this study, we provide an overview of the current knowledge concerning AAs, paying special emphasis to EAAs and explaining, to some extent, certain mechanisms and functions of these compounds, from mulberry leaves to larvae-pupae and fish diets.

Cotton adapts to Na2SO4 stress by regulating the metabolic intensity and distribution of metabolites in roots and leaves

Significant Na2SO4 stress severely restricts cotton production in Xinjiang. However, the tolerance mechanism of cotton to Na2SO4 stress is not yet fully understood. This study set up two treatments, normal soil (control, CK) and Na2SO4 stress (Na2SO4, SS), to explore the effects of Na2SO4 stress on the physiological metabolism of cotton leaves and roots. Compared with CK, the total biomass and net photosynthetic stress rate decreased significantly (P < 0.05) by 49.0 and 14.7%, respectively. Additionally, the relative conductivity, malondialdehyde content, superoxide dismutase, peroxidase, and catalase activities of leaves increased significantly by 114.5, 99.8, 160, 16.8, and 117%, respectively. A tandem mass tag (TMT) proteomics analysis identified 319 and 583 differentially expressed proteins in roots and leaves, respectively. They mainly participate in amino acid metabolism, such as alanine, aspartic acid, and glutamate metabolism; histidine metabolism; tyrosine metabolism; tryptophan metabolism; energy metabolism, such as glycolysis; the tricarboxylic acid cycle; phosphorus oxide metabolism; lipid metabolism, such as fatty acid biosynthesis; glycerol phospholipid metabolism; steroid biosynthesis; and steroid hormone biosynthesis. Metabolomic data also showed significant changes in amino acid metabolism, organic acid metabolism, and carbohydrate metabolism in the roots and leaves. Na2SO4 stress inhibited metabolism in cotton roots but promoted metabolism in cotton leaves. Under Na2SO4 stress, cotton may prioritize the use of limited photosynthetic products to maintain the health and life activities of its leaves, while also transporting some organic matter from the leaves to the roots to maintain normal metabolic activity of the roots.

Applying metabolic modeling and multi-omics to elucidate the biotransformation mechanisms of marine algal toxin domoic acid (DA) in sediments

Domoic acid (DA)-producing algal blooms are a global marine environmental issue. However, there has been no previous research addressing the question regarding the fate of DA in marine benthic environments. In this work, we investigated the DA fate in the water-sediment microcosm via the integrative analysis of a top-down metabolic model, metagenome, and metabolome. Results demonstrated that biodegradation is the leading mechanism for the nonconservative attenuation of DA. Specifically, DA degradation was prominently completed by the sediment aerobic community, with a degradation rate of 0.0681 ± 0.00954 d−1. The DA degradation pathway included hydration, dehydrogenation, hydrolysis, decarboxylation, automatic ring opening of hydration, and β oxidation reactions. Moreover, the reverse ecological analysis demonstrated that the microbial community transitioned from nutrient competition to metabolic cross-feeding during DA degradation, further enhancing the cooperation between DA degraders and other taxa. Finally, we reconstructed the metabolic process of microbial communities during DA degradation and confirmed that the metabolism of amino acid and organic acid drove the degradation of DA. Overall, our work not only elucidated the fate of DA in marine environments but also provided crucial insights for applying metabolic models and multi-omics to investigate the biotransformation of other contaminants.

PSI-17 Effect of timing of high dietary zinc supplementation on the microbiome of gestating sows and their piglets

Abstract The objective of this study was to assess if high dietary zinc (Zn) fed to gestating sows modulates the microbiome of the sow and that of their offspring. Sows were fed 1 of 3 dietary treatments: 1) Control: a corn-soybean meal-based diet containing 125 ppm total supplemental zinc, 2) Breed-to-Farrow: as Control + 141 ppm supplemental Zn as ZnSO4 fed from 5 d post-breeding to farrowing; and 3) Day 110-to-Farrow: as Control + 2,715 ppm supplemental Zn as ZnSO4 starting on d 110 of gestation until farrowing. A subset of third parity sows (n = 30; 10 per treatment) were selected to assess the microbiome of colostrum, milk, and rectal and vaginal surfaces of sows. At farrowing, 4 pigs per litter (n = 120) were selected based on birthweight (BiW; 2 average BiW pigs and 2 pigs with BiW below the litter average) were selected to assess the piglet gut microbiome on the day of birth (d 0) and d5 of age. 16S rRNA sequencing was implemented for colostrum and milk samples while all other sample types were sequenced using shotgun metagenomics to determine taxonomic and functional profiles. Measures of alpha and beta diversity were conducted along with determination of differentially abundant taxa and pathways in tandem with generalized linear mixed models. Greater dietary concentrations of Zn fed to gestating sows minimally affected their colostrum, milk, and vaginal microbiome. However, fecal samples of Breed-to-Farrow sows showed decreased abundance of potentially pathogenic bacteria such as Salmonella enterica and Shigella flexneri and greater abundance of bacteria typically involved in fiber fermentation compared with Control sows (Figure 1a). Piglets born to Day 110-to-Farrow sows also showed greater abundance of some taxa typically involved in fiber breakdown and short chain fatty acid (SCFA) generation on d 5 compared with Control pigs (Figure 1b). At d 0, Breed-to-Farrow piglets showed less abundance of methanogenic archaea and differential abundance of taxa with potentially pathogenic roles, compared with Control pigs (Figure 1c). Gene families and pathways playing roles in central metabolic functions (starch, pyruvate, sucrose, amino acid metabolism) were more abundant in Breed-to-Farrow piglets compared with pigs born to Control sows on d 0 and 5 of age. In conclusion, greater Zn fed to gestating sows impacted the abundance of gut taxa with potential roles in SCFA-production and pathogenicity in both sow and piglet, despite overall minor effects. However, the physiological significance of these findings for the sow and piglet remains unclear.

1 The role of gut microbiota on regulation of growth and metabolism by branched-chain amino acids

Abstract Branched-chain amino acids (BCAA) including leucine, isoleucine and valine are essential amino acids, which are involved in energy homeostasis and regulation of many physiological paradigms including growth. The BCAA serve not only as an essential substrate in the synthesis of body proteins, but also have an important role in regulation of protein turnover. The effects of BCAA on growth and metabolism are likely mediated through different pathways including shifts in metabolic profile in peripheral organs, oxidative capacity of muscle, gut development, and protein metabolism in muscle. Although it has not been appropriately studied or fully dissected, the impact of BCAA on growth and metabolism is thought to lie in the alteration of gut microbiota by BCAA. It has long been believed that gut microbiota, more specifically, the activity of the microbiome and its metabolic products, directly influence a variety of aspects in metazoan physiology. For example, deregulation of bacterial community structure has been linked with host longevity and stress resistance, the pathogenesis of several disorders, regulation of appetite. Multiple studies have demonstrated that modulation of dietary BCAA levels could elicit clear shifts in gut microbial community structure. As part of “Physiology Symposium: The Microbiome and the Host: Functional Role in Metabolism, Immunity, and Gut-Brain Axis”, the possible involvement of intestinal microbiota on regulatory roles of BCAA on growth and metabolism will be discussed.

126 A nutritional solution based on calcidiol (25-OH-D3, HyD) and triterpenoid affects muscle protein synthesis pathways in grower-finisher pigs

Abstract To boost profitability in pig production, it is important to achieve increased lean growth rates and maximize efficiency, especially in grower-finisher pigs where feed intakes are high. Molecular research, especially the study of gene expression, is a proven tool for understanding the precise mechanisms behind muscle tissue growth, including a recent focus on pathways such as the mammalian target of rapamycin (mTOR). In the current work, gene expression analyses were used to study the mode of action of the combination of calcidiol (25-OH-D3, HyD) and triterpenoid, which has shown significant growth and efficiency improvements in grower-finisher pigs (McCormack et al., 2024). Three experimental diets were evaluated for 7 wk; Positive control: 0.7% total Ca, 0.36% total P, vit D3 at 1500IU/kg feed (PC), negative control: PC diet + 30% reduced Ca and 10% reduced P (NC), and NC diet with 1,500IU D3 in calcidiol form (25-OH-D3, HyD) and triterpenoid (NC+). At 19 wk of age, 16 animals per treatment were sacrificed and tissue samples were taken from the longissimus muscle and preserved in RNA later solution. The RNA was extracted, quality control checked, and mRNA sequenced using the Illumina platform with 150 base pair paired-end sequencing and 30M read depth. The sequenced data were aligned to the Sus scrofa reference genome (Sscrofa11.1) using Kallisto. Data were normalized and analyzed for differentially expressed genes (DEGs) between treatments using DeSeq2. Genes were assigned to biological pathways using Biofractal’s customisation of the Reactome pathway database. For statistical analysis, RNA integrity number and treatment were included in the model. In the PC compared with the NC, there were 71 DEGs using a false discovery rate (FDR) of &amp;lt; 0.10. Altered pathways included the inhibition of cellular stress pathways and increased cell turnover in the muscle of PC compared with NC pigs. In the NC+ compared with the NC, there were 155 DEGs (FDR &amp;lt; 0.10). The most significantly upregulated gene in the NC+ treatment was adenylate cyclase (FDR &amp;lt; 0.001), an upstream regulator of several pathways related to energy metabolism and muscle protein synthesis. This mechanism was confirmed in the pathway analysis, which found that the NC+ treatment activated PKA-mediated phosphorylation of CREB, a pathway that inhibits muscle atrophy. Furthermore, the NC+ treatment activated several pathways related to muscle growth, including the mammalian target of rapamycin complex 1 (mTORC1). In this study the addition of calcidiol (25-OH-D3, HyD) and triterpenoid to the diet was found to specifically affect molecular pathways in the muscle of grower-finisher pigs involved in both the inhibition of muscle breakdown as well as activating muscle growth.

Trehalose enhances the resistance of Lactiplantibacillus plantarum LIP-1 to spray- and freeze-drying treatments by regulating amino acid metabolism

The effect of adding trehalose in the culture medium on Lactiplantibacillus plantarum LIP-1 was investigated during spray- and freeze-drying. Although previous studies reported that the enhancement of bacterial resistance is due to intracellular trehalose accumulation, our study revealed that it was related to trehalose metabolism by the strain, and not accumulation. The underlying mechanisms were mainly related to the activation of l-glutamic acid and cysteine metabolic pathways during trehalose metabolism. First, murL, murD, and vanY in the l-glutamic acid metabolic pathway were significantly upregulated, increasing peptidoglycan synthesis and thus improving the cell wall integrity during drying process. Second, gshA in the cysteine metabolic pathway was upregulated, increasing intracellular glutathione content, enhancing antioxidant capacity, and thereby reducing the degree of cell membrane damage during drying process. Third, alkaline substances produced during l-glutamic acid and cysteine metabolisms increased the intracellular pH and reduced the degree of DNA damage caused by acid stress.

PSV-16 Effect of precision feeding and functional amino acids on immune response and protein metabolism of growing pigs raised in poor sanitary conditions

Abstract The activation of the immune system reduces the nutrient availability for growth and increases the variability among pigs. Functional amino acids (AA) supplementation can reduce the negative effects of immune activation. Additionally, providing daily tailored diets using individual precision feeding (IPF) was shown to account for individual variability. Therefore, we hypothesized that the association of IPF and functional AA supplementation could reduce the negative effect of immune-challenged pigs fed with daily tailored diets. The aim of this study was to assess performance and blood parameters variation of growing pigs under poor sanitary conditions while being fed functional AA 120% above the estimated INRA AA ratios within IPF, compared with a conventional group-phase (GP) feeding system. The sanitary condition was characterized by oral inoculation of 2 × 109 cfu of Salmonella typhimurium and manure spreading on the pen floor on d 0. Sixty gilts (23 ± 2.8 kg body weight; BW) were distributed in a complete randomized block design in a 2 x 2 factorial arrangement composed of 2 diets: CN with 100% INRA AA ratio or AA+ with 120% of the ratio for Met, Thr and Trp; and 2 feeding systems: GP or IPF. GP pigs received a single diet matching the SID Lys requirement of the 80th-percentile pig at the beginning of the trial whereas IPF pigs received a diet tailored daily to each pig requirement. All pigs were group-housed and fed ad libitum for 28 d by automatic feeders. Body weight was measured at d 0 and 28 and feed intake was recorded daily. Blood samples were collected at d 0, 7 and 28. Data were analyzed with diet and feeding systems and their interactions as fixed effects and BW blocks as random effect. Blood parameters were analyzed as repeated measurements over time. The pig was considered the experimental unit. No diet effect or interactions were observed for any variable (P &amp;gt; 0.05), suggesting that only supplementing Met, Trp, and Thr is not enough to support growth during a sanitary challenge (Table 1). Haptoglobin and IgG increased linearly whereas IgA, urea, and creatinine had a quadratic increase over time (P &amp;lt; 0.05; Table 2). The IPF decreased growth performance and increased serum IgA and creatinine (P &amp;lt; 0.05), mostly due to the fact that IPF reduces AA provision compared with GP system. The IPF model, as most mathematical models, does not account for the AA and energy costs related to the immune challenge. Therefore, IPF might have underestimated the requirements of the pigs, and limited the amount of nutrients provided. In conclusion, the combined effect of IPF and functional AA supplementation was not able to reduce the negative effect of the sanitary challenge.

Proteomic characterization of the different stages of seed germination in Cupressus gigantea

Abstract Seed germination is a pivotal period of plant growth and development. This process can be divided into four major stages, swelling absorption, seed coat dehiscence, radicle emergence and radicle elongation. Cupressus gigantea, a tree native to Tibet, China, is characterized by its resistance to stresses such as cold, and drought, and has a high economic and ecological value. Nevertheless, given its unique geographic location, its seeds are difficult to germinate. Therefore, it is crucial to explore the mechanisms involved in seed germination in this species to improve the germination efficiency of its seeds, thereby protecting this high-quality resource. Here, our findings indicate that seed germination was enhanced when exposed to a 6-h/8-h light/dark photoperiod, coupled with a temperature of 20°C. Furthermore, the application of exogenous GA3 (1 mg/ml, about 2.9 mM) stimulated the germination of C. gigantea seeds. Subsequently, proteomics was used to detect changes in protein expression during the four stages of seed germination. We identified 34 differentially expressed proteins (DEPs), including 13 at the radicle pre-emergence stage, and 17 at the radicle elongation stage. These DEPs were classified into eight functional groups, cytoskeletal proteins, energy metabolism, membrane transport, stress response, molecular chaperones, amino acid metabolism, antioxidant system and ABA signalling pathway. Most of them were found to be closely associated with amino acid metabolism. Combined, these findings indicate that, along with temperature and light, exogenous GA3 can increase the germination efficiency of C. gigantea seeds. Our study also offers insights into the changes in protein expression patterns in C. gigantea seeds during germination.

MtPIN4 plays critical roles in amino acid biosynthesis and metabolism of seed in Medicago truncatula.

The regulation of seed development is critical for determining crop yield. Auxins are vital phytohormones that play roles in various aspects of plant growth and development. However, its role in amino acid biosynthesis and metabolism in seeds is not fully understood. In this study, we identified a mutant with small seeds through forward genetic screening in Medicago truncatula. The mutated gene encodes MtPIN4, an ortholog of PIN1. Using molecular approaches and integrative omics analyses, we discovered that auxin and amino acid content significantly decreased in mtpin4 seeds, highlighting the role of MtPIN4-mediated auxin distribution in amino acid biosynthesis and metabolism. Furthermore, genetic analysis revealed that the three orthologs of PIN1 have specific and overlapping functions in various developmental processes in M. truncatula. Our findings emphasize the significance of MtPIN4 in seed development and offer insights into the molecular mechanisms governing the regulation of seed size in crops. This knowledge could be applied to enhance crop quality by targeted manipulation of seed protein regulatory pathways.

Combining Transcriptome- and Metabolome-Analyzed Differentially Expressed Genes and Differential Metabolites in Development Period of Caoyuanheimo-1 (Agaricus sp.) from Inner Mongolia, China

Caoyuanheimo-1 (Agaricus sp.) is a delectable mushroom native to Inner Mongolia, China, belonging to the Agaricus genus and valued for both its edible and medicinal properties. Although it has been cultivated to a certain extent, the molecular mechanisms regulating its development remain poorly understood. Building on our understanding of its growth and development conditions at various stages, we conducted transcriptomic and metabolomic studies to identify the differentially expressed genes (DEGs) and metabolites throughout its growth cycle. Simultaneously, we analyzed the synthesis pathways and identified several key genes involved in the production of terpenoids, which are secondary metabolites with medicinal value widely found in mushrooms. A total of 6843 unigenes were annotated, and 449 metabolites were detected in our study. Many of these metabolites and differentially expressed genes (DEGs) are involved in the synthesis and metabolism of amino acids, such as arginine, cysteine, methionine, and other amino acids, which indicates that the genes related to amino acid metabolism may play an important role in the fruiting body development of Caoyuanheimo-1. Succinic acid also showed a significant positive correlation with the transcriptional level changes of nine genes, including laccase-1 (TRINITY_DN5510_c0_g1), fruiting body protein SC3 (TRINITY_DN3577_c0_g1), and zinc-binding dihydrogenase (TRINITY_DN2099_c0_g1), etc. Additionally, seventeen terpenoids and terpenoid-related substances were identified, comprising five terpenoid glycosides, three monoterpenoids, two diterpenoids, one sesquiterpenoid, one sesterterpenoid, two terpenoid lactones, and three triterpenoids. The expression levels of the genes related to terpenoid synthesis varied across the three developmental stages.

Nitric oxide alleviates programmed cell death induced by cadmium in Solanum lycopersicum seedlings through protein S-nitrosylation

Cadmium (Cd), as a non-essential and toxic heavy metal in plants, has deleterious effects on plant physiological and biochemical processes. Nitric oxide (NO) is one of the most important signaling molecules for plants to response diverse stresses. Here, we found that Cd-induced programmed cell death (PCD) was accompanied by NO bursts, which exacerbated cell death when NO was removed and vice versa. Proteomic analysis of S-nitrosylated proteins showed that the differential proteins in Cd-induced PCD and in NO-alleviated PCD mainly exist together in carbohydrate metabolism and amino acid metabolism, while some of the differential proteins exist alone in metabolism of cofactors and vitamins and lipid metabolism. Meanwhile, S-nitrosylation of proteins in porphyrin and chlorophyll metabolism and starch and sucrose metabolism could explain the leaf chlorosis induced by PCD. Moreover, protein transport protein SEC23, ubiquitinyl hydrolase 1 and pathogenesis-related protein 1 were identified to be S-nitrosylated in vivo, and their expressions were increased in Cd-induced PCD while decreased in NO treatment. Similar results were obtained in tomato seedlings with higher S-nitrosylation. Taken together, our results indicate that NO might be involved in the regulation of Cd-induced PCD through protein S-nitrosylation, especially proteins involved in PCD response.

Exploring the carbon skeleton cycling regulation mechanism of single-wavelength light quality promoting the accumulation of polysaccharides in Spirulina platensis FACHB-439: Based on transcriptomics

Carbon dioxide can be converted into carbohydrates by Spirulina to promote carbon neutrality and produce high added value bio-functional compounds (e.g. polysaccharides). This study explored the effects of different single-wavelength light qualities on Spirulina polysaccharides and the differences in gene expression. The experiment results indicated that red light could significantly increase the content of polysaccharides in Spirulina (116.88 mg/g), followed by blue light (99.83 mg/g), green light (95.23 mg/g), yellow light (50.50 mg/g), while the white light control group was 69.59 mg/g. Transcription analysis results revealed that red light adjusted the intracellular carbon skeleton cycling between glycolysis/gluconeogenesis pathway, pyruvate and amino acid metabolism, and protein synthesis, ultimately promoting the accumulation of carbon sources towards polysaccharide synthesis. These findings offer theoretical basis and data support for the promising carbon fixation and reutilization based on blue-green algae.

Acetylation proteomics and metabolomics analyses reveal the involvement of starch synthase undergoing acetylation modification during UV-B stress resistance in Rhododendron Chrysanthum Pall

BackgroundRhododendron chrysanthum Pall. (R. chrysanthum) is a plant that lives in high mountain with strong UV-B radiation, so R. chrysanthum possess resistance to UV-B radiation. The process of stress resistance in plants is closely related to metabolism. Lysine acetylation is an important post-translational modification, and this modification process is involved in a variety of biological processes, and affected the expression of enzymes in metabolic processes. However, little is known about acetylation proteomics during UV-B stress resistance in R. chrysanthum.ResultsIn this study, R. chrysanthum OJIP curves indicated that UV-B stress damaged the receptor side of the PSII reaction center, with a decrease in photosynthesis, a decrease in sucrose content and an increase in starch content. A total of 807 differentially expressed proteins, 685 differentially acetylated proteins and 945 acetylation sites were identified by quantitative proteomic and acetylation modification histological analysis. According to COG and subcellular location analyses, DEPs with post-translational modification of proteins and carbohydrate metabolism had important roles in resistance to UV-B stress and DEPs were concentrated in chloroplasts. KEGG analyses showed that DEPs were enriched in starch and sucrose metabolic pathways. Analysis of acetylation modification histology showed that the enzymes in the starch and sucrose metabolic pathways underwent acetylation modification and the modification levels were up-regulated. Further analysis showed that only GBSS and SSGBSS changed to DEPs after undergoing acetylation modification. Metabolomics analyses showed that the metabolite content of starch and sucrose metabolism in R. chrysanthum under UV-B stress.ConclusionsDecreased photosynthesis in R. chrysanthum under UV-B stress, which in turn affects starch and sucrose metabolism. In starch synthesis, GBSS undergoes acetylation modification and the level is upregulated, promotes starch synthesis, making R. chrysanthum resistant to UV-B stress.

Utilizing transcriptomics and proteomics to unravel key genes and proteins of Oryza sativa seedlings mediated by selenium in response to cadmium stress

BackgroundCadmium (Cd) pollution has declined crop yields and quality. Selenium (Se) is a beneficial mineral element that protects plants from oxidative damage, thereby improving crop tolerance to heavy metals. The molecular mechanism of Se-induced Cd tolerance in rice (Oryza sativa) is not yet understood. This study aimed to elucidate the beneficial mechanism of Se (1 mg/kg) in alleviating Cd toxicity in rice seedlings.ResultsExogenous selenium addition significantly improved the toxic effect of cadmium stress on rice seedlings, increasing plant height and fresh weight by 20.53% and 34.48%, respectively, and increasing chlorophyll and carotenoid content by 16.68% and 15.26%, respectively. Moreover, the MDA, ·OH, and protein carbonyl levels induced by cadmium stress were reduced by 47.65%, 67.57%, and 56.43%, respectively. Cell wall metabolism, energy cycling, and enzymatic and non-enzymatic antioxidant systems in rice seedlings were significantly enhanced. Transcriptome analysis showed that the expressions of key functional genes psbQ, psbO, psaG, psaD, atpG, and PetH were significantly up-regulated under low-concentration Se treatment, which enhanced the energy metabolism process of photosystem I and photosystem II in rice seedlings. At the same time, the up-regulation of LHCA, LHCB family, and C4H1, PRX, and atp6 functional genes improved the ability of photon capture and heavy metal ion binding in plants. Combined with proteome analysis, the expression of functional proteins OsGSTF1, OsGSTU11, OsG6PDH4, OsDHAB1, CP29, and CabE was significantly up-regulated under Se, which enhanced photosynthesis and anti-oxidative stress mechanism in rice seedlings. At the same time, it regulates the plant hormone signal transduction pathway. It up-regulates the expression response process of IAA, ABA, and JAZ to activate the synergistic effect between each cell rapidly and jointly maintain the homeostasis balance.ConclusionOur results revealed the regulation process of Se-mediated critical metabolic pathways, functional genes, and proteins in rice under cadmium stress. They provided insights into the expression rules and dynamic response process of the Se-mediated plant resistance mechanism. This study provided the theoretical basis and technical support for crop safety in cropland ecosystems and cadmium-contaminated areas.

Ecotoxicological effects of polyethylene microplastics and lead (Pb) on the biomass, activity, and community diversity of soil microbes

Microplastics and heavy metals are ubiquitous and persistent contaminants that are widely distributed worldwide, yet little is known about the effects of their interaction on soil ecosystems. A soil incubation experiment was conducted to investigate the individual and combined effects of polyethylene microplastics (PE-MPs) and lead (Pb) on soil enzymatic activities, microbial biomass, respiration rate, and community diversity. The results indicate that the presence of PE-MPs notably reduced soil pH and elevated soil Pb bioavailability, potentially exacerbated the combined toxicity on the biogeochemical cycles of soil nutrients, microbial biomass carbon and nitrogen, and the activities of soil urease, sucrase, and alkaline phosphatase. Soil CO2 emissions increased by 7.9% with PE-MPs alone, decreased by 46.3% with single Pb, and reduced by 69.4% with PE-MPs and Pb co-exposure, compared to uncontaminated soils. Specifically, the presence of PE-MPs and Pb, individually and in combination, facilitated the soil metabolic quotient, leading to reduced microbial metabolic efficiency. Moreover, the addition of Pb and PE-MPs modified the composition of the microbial community, leading to the enrichment of specific taxa. Tax4Fun analysis showed the effects of Pb, PE-MPs and their combination on the biogeochemical processes and ecological functions of microbes were mainly by altering amino acid metabolism, carbohydrate metabolism, membrane transport, and signal transduction. These findings offer valuable insights into the ecotoxicological effects of combined PE-MPs and Pb on soil microbial dynamics, reveals key assembly mechanisms and environmental drivers, and highlights the potential threat of MPs and heavy metals to the multifunctionality of soil ecosystems.

Impact of the Oral Administration of Polystyrene Microplastics on Hepatic Lipid, Glucose, and Amino Acid Metabolism in C57BL/6Korl and C57BL/6-Lepem1hwl/Korl Mice.

The impact of microplastics (MPs) on the metabolic functions of the liver is currently unclear and not completely understood. To investigate the effects of the administration of MPs on the hepatic metabolism of normal and obese mice, alterations in the lipid, glucose (Glu), and amino acid regulation pathways were analyzed in the liver and adipose tissues of C57BL/6Korl (wild type, WT) or C57BL/6-Lepem1hwl/Korl mice (leptin knockout, Lep KO) orally administered polystyrene (PS) MPs for 9 weeks. Significant alterations in the lipid accumulation, adipogenesis, lipogenesis, and lipolysis pathways were detected in the liver tissue of MP-treated WT and Lep KO mice compared to the vehicle-treated group. These alterations in their liver tissues were accompanied by an upregulation of the serum lipid profile, as well as alterations in the adipogenesis, lipogenesis, and lipolysis pathways in the adipose tissues of MP-treated WT and Lep KO mice. Specifically, the level of leptin was increased in the adipose tissues of MP-treated WT mice without any change in their food intake. Also, MP-induced disruptions in the glycogenolysis, Glu transporter type 4 (GLUT4)-5' AMP-activated protein kinase (AMPK) signaling pathway, levels of lipid intermediates, and the insulin resistance of the liver tissues of WT and Lep KO mice were observed. Furthermore, the levels of seven endogenous metabolites were remarkably changed in the serum of WT and Lep KO mice after MP administrations. Finally, the impact of the MP administration observed in both types of mice was further verified in differentiated 3T3-L1 adipocytes and HepG2 cells. Thus, these results suggest that the oral administration of MPs for 9 weeks may be associated with the disruption of lipid, Glu, and amino acid metabolism in the liver tissue of obese WT and Lep KO mice.