An anthocyanin activation gene underlies the purple central flower pigmentation in wild carrot.

Many organisms have complex pigmentation patterns. However, how these patterns are formed remains largely unknown. In wild carrot (Daucus carota subsp. carota), which is also known as Queen Anne's lace, one or several purple central flowers occur in white umbels. Here, we investigated the unique central flower pigmentation pattern in wild carrot umbels. Using wild and cultivated carrot (Daucus carota subsp. sativus L.) accessions, transcriptome analysis, protein interaction, stable transformation, and CRISPR/Cas9-mediated knockout, a anthocyanin-activating R2R3-myeloblastosis (MYB) gene, Purple Central Flower (DcPCF), was identified as the causal gene that triggers only central flowers to possess the purple phenotype. The expression of DcPCF was only detected in tiny central flowers. We propose that the transition from purple to nonpurple flowers in the center of the umbel occurred after three separate adverse events: insertion of transposons in the promoter region, premature termination of the coding sequence (caused by a C-T substitution in the open reading frame), and the emergence of unknown anthocyanin suppressors. These three events could have occurred either consecutively or independently. The intriguing purple central flower pattern and its underlying mechanism may provide evidence that it is a remnant of ancient conditions of the species, reflecting the original appearance of Umbelliferae (also called Apiaceae) when a single flower was present.

The emerging roles of hydrogen sulfide in ferroptosis.

SIGNIFICANCE: Ferroptosis, a form of regulated cell death characterized by a large amount of lipid peroxidation-mediated membrane damage, joins the evolution of multisystem diseases. For instance, neurodegenerative diseases, chronic obstructive pulmonary disease and acute respiratory distress syndrome, osteoporosis and osteoarthritis, and so on. Since being identified as the third gasotransmitter in living organisms, the intricate role of hydrogen sulfide (H2S) in ferroptosis has emerged at the forefront of research. RECENT ADVANCES: The discovery of novel targets in the relevant metabolic pathways, including transferrin receptor 1, cystine/glutamate antiporter, and others, coupled with the exploration of new signaling pathways, particularly the p53 signaling pathway and the nitric oxide / nuclear factor erythroid 2-related factor 2 signaling pathway, and so on. Many diseases such as emphysema and airway inflammation, myocardial diseases, endothelial dysfunction in aging arteries, and traumatic brain injury have recently been found to be alleviated directly by H2S inhibition of ferroptosis. Safe, effective, and tolerable novel H2S donors have been developed and have shown promising results in phase I clinical trials. CRITICAL ISSUES: Complicated crosstalk between ferroptosis signaling pathway and oncogenic factors results in the risk of cancer when inhibiting ferroptosis. Notably, targeted delivery of H2S is still a challenging task. FUTURE DIRECTIONS: Discovering more reliable and stable novel H2S donors and achieving their targeted delivery will enable further clinical trials for diseases associated with ferroptosis inhibition by H2S, determining their safety, efficacy, and tolerance.

Effects of Mobile Applications on Weight-Related, Behavior and Metabolic Outcomes for Adults with Overweight and Obesity: A Systematic Review and Meta-Analysis.

The meta-analysis aimed to explore the effects of mobile phone applications on weight-related, behavior, and metabolic outcomes among adults with overweight and obesity. Six databases were searched for relevant randomized controlled trials (RCTs) published between January 1, 2010 and November 7, 2023 in English. Two independent authors conducted study selection, data extraction, quality assessment. The effect size of interventions was calculated using mean difference. A random-effects model was applied for data analysis. A total of 27 studies were included. The results indicated that mobile phone application intervention reduced weight (MD=-1.38 kg, P<0.001, 95% CI -1.97 to -0.80), BMI (MD=-0.44 kg/m2, P<0.001, 95% CI -0.57 to -0.30), WC (MD=-2.13 cm, P=0.004, 95% CI -3.57 to -0.69), fat mass, and DBP (MD=-2.04 mmHg, P=0.01, 95% CI -3.65 to 0.44) with statistical significance. Future studies could consider how to optimize app interventions through behavior change strategies to enhance their overall effectiveness.

Boosting 2000-Fold Hypergolic Ignition Rate of Carborane by Substitutes Migration in Metal Clusters.

Hypergolic propellants rely on fuel and oxidizer that spontaneously ignite upon contact, which fulfill a wide variety of mission roles in launch vehicles and spacecraft. Energy-rich carboranes are promising hypergolic fuels, but triggering their energy release is quite difficult because of their ultrastable aromatic cage structure. To steer the development of carborane-based high-performance hypergolic material, carboranylthiolated compounds integrated with atomically precise copper clusters are presented, yielding two distinct isomers, Cu14B-S and Cu14C-S, both possessing similar ligands and core structures. With the migration of thiolate groups from carbon atoms to boron atoms, the ignition delay (ID) time shortened from 6870 to 3 ms when contacted with environmentally benign oxidizer high-test peroxide (HTP, with a H2O2 concentration of 90%). The extraordinarily short ignition ID time of Cu14B-S is ranking among the best of HTP-active hypergolic materials. The experimental and theoretical findings reveal that benefitting from the migration of thiolate groups, Cu14B-S, characterized by an electron-rich metal kernel, displays enhanced reducibility and superior charge transfer efficiency. This results in exceptional activation rates with HTP, consequently inducing carborane combustion and the simultaneous release of energy. This fundamental investigation shed light on the development of advanced green hypergolic propulsion systems.

A biocatalytic cascade in enzyme/metal continuous-microflow microgel with stable intermediate channel for point-of-care biosensing.

A fast and accurate method for ultrasensitive monitoring of substrate is significant for cascade molecular detection. Here, we synthesize a glucose oxidase (GOx) microgel with iron coordination (Fe/GOx microgel). The microgel is cross-linked by chitosan and iron ion coordination which construct a tubular structure. Powder X-ray diffraction and Brunauer-Emmett-Teller results confirm the tubular crystal structure with a high specific surface area is formed in the microgel. The tubular structure offers a stable channel for intermediate transport which ensures the stabilization for the intermediate transport, and high specific surface area enhances the interaction between substrates and catalysts. As a result, the sensitivity of the Fe/GOx microgel is 175.5 µA mM-1 cm-2 and the lowest detection limit is 4.42 µM. In addition, the nanoscale Fe/GOx microgel also has the characteristics of reusability and maintains its activity after five times of catalysis. The generation of free radicals during the catalytic process can be detected by light detection and electrochemical signal detection within different detection limits. Therefore, Fe/GOx microgel provides a new platform and catalyst for the precise detection of cascade catalysis.

DcGST1, encoding a glutathione S-transferase activated by DcMYB7, is the main contributor to anthocyanin pigmentation in purple carrot.

The color of purple carrot taproots mainly depends on the anthocyanins sequestered in the vacuoles. Glutathione S-transferases (GSTs) are key enzymes involved in anthocyanin transport. However, the precise mechanism of anthocyanin transport from the cytosolic surface of the endoplasmic reticulum (ER) to the vacuoles in carrots remains unclear. In this study, we conducted a comprehensive analysis of the carrot genome, leading to the identification of a total of 41 DcGST genes. Among these, DcGST1 emerged as a prominent candidate, displaying a strong positive correlation with anthocyanin pigmentation in carrot taproots. It was highly expressed in the purple taproot tissues of purple carrot cultivars, while it was virtually inactive in the non-purple taproot tissues of purple and non-purple carrot cultivars. DcGST1, a homolog of Arabidopsis thaliana TRANSPARENT TESTA 19 (TT19), belongs to the GSTF clade and plays a crucial role in anthocyanin transport. Using the CRISPR/Cas9 system, we successfully knocked out DcGST1 in the solid purple carrot cultivar 'Deep Purple' ('DPP'), resulting in carrots with orange taproots. Additionally, DcMYB7, an anthocyanin activator, binds to the DcGST1 promoter, activating its expression. Compared with the expression DcMYB7 alone, co-expression of DcGST1 and DcMYB7 significantly increased anthocyanin accumulation in carrot calli. However, overexpression of DcGST1 in the two purple carrot cultivars did not change the anthocyanin accumulation pattern or significantly increase the anthocyanin content. These findings improve our understanding of anthocyanin transport mechanisms in plants, providing a molecular foundation for improving and enhancing carrot germplasm.

Highly stable glucose oxidase polynanogel@MXene/chitosan electrochemical biosensor based on a multi-stable interface structure for glucose detection.

It is a challenging and meaningful task to design an enzyme electrochemical biosensor that can maintain high sensitivity while improving stability. In this study, we constructed an enzyme electrochemical biosensor by preparing nanocomposites with multi-stable interface structures. Specifically, the nanocomposite (PGOx@MXene/CS) was prepared by efficient electrostatic assembly of GOx polynanogel (PGOx) onto MXene nanosheets. PGOx could enhance enzyme stability, while the extensive the large specific surface area of MXene could realize the efficient loading of nanocapsules (PGOx) and catalyze the decomposition of toxic intermediate H2O2, thereby reducing its influence on the stability of enzyme. The linear range of the constructed glucose sensor was 0.03-16.5 mM, the sensitivity was 48.98 µA mM-1·cm-2, and the detection limit was 3.1 µM. After 200 cycles, the current still remained at 85.83% of the initial current value. The high sensitivity, excellent selectivity and great reproducibility verified the effectiveness of the system we constructed. The multi-stable enzyme electrochemical biosensor had a wide application prospect in stable and continuous blood glucose detection.

Generating colorful carrot germplasm through metabolic engineering of betalains pigments.

Betalains are tyrosine-derived plant pigments exclusively found in the Caryophyllales order and some higher fungi and generally classified into two groups: red-violet betacyanins and yellow-orange betaxanthins. Betalains attract great scientific and economic interest because of their relatively simple biosynthesis pathway, attractive colors and health-promoting properties. Co-expressing two core genes BvCYP76AD1 and BvDODA1 with or without a glycosyltransferase gene MjcDOPA5GT allowed the engineering of carrot (an important taproot vegetable) to produce a palette of unique colors. The highest total betalains content, 943.2 µg·g-1 DW, was obtained in carrot taproot transformed with p35S:RUBY which produces all of the necessary enzymes for betalains synthesis. Root-specific production of betalains slightly relieved tyrosine consumption revealing the possible bottleneck in betalains production. Furthermore, a unique volcano-like phenotype in carrot taproot cross-section was created by vascular cambium-specific production of betalains. The betalains-fortified carrot in this study is thus anticipated to be used as functional vegetable and colorful carrot germplasm in breeding to promote health.

Construction of molecular enrichment accelerators via assembly of enzyme surface grafted polymer and cyclodextrin achieving rapid and stable ester catalysis for biodiesel synthesis.

Efficient and stable catalysis has always been the core concept of enzyme catalysis in industrial processes for manufacturing. Here, we constructed molecular enrichment accelerators to synergistically enhance enzyme activity and stability by assembling enzyme surface grafted polymer and cyclodextrin. At 40 °C, the enzyme activity of CalB-PNIPAM212/ß-CD was 2.9 times that of CalB-PNIPAM212. The enzyme activity of CalB-PNIPAM428/γ-CD had reached 1.61 times that of CalB. At the same time, the stability of CalB-PNIPAM212/ß-CD and CalB-PNIPAM428/γ-CD are slightly better than that of CalB under high temperature, organic solution and extreme pH conditions. The synergistic increase in activity and stability of the lipase-polymer assembly was achieved due to the structure of assembly, in which the role of cyclodextrin could enrich substrate affecting molecular diffusion. In addition, the lipase-polymer assembly proved to be an efficient catalyst for biodiesel synthesis, with a biodiesel conversion 1.4 times that of CalB at 60 °C. Therefore, this simple and low-cost lipase-polymer assembly provides new possibilities for the construction of high-efficiency industrial biocatalytic catalysts.

A MYB activator, DcMYB11c, regulates carrot anthocyanins accumulation in petiole but not taproot.

The first domesticated carrots were thought to be purple carrots rich in anthocyanins. The anthocyanins biosynthesis in solid purple carrot taproot was regulated by DcMYB7 within P3 region containing a gene cluster of six DcMYBs. Here, we described a MYB gene within the same region, DcMYB11c, which was highly expressed in the purple pigmented petioles. Overexpression of DcMYB11c in 'Kurodagosun' (KRDG , orange taproot carrot with green petioles) and 'Qitouhuang' (QTHG , yellow taproot carrot with green petioles) resulted in deep purple phenotype in the whole carrot plants indicating anthocyanins accumulation. Knockout of DcMYB11c in 'Deep Purple' (DPPP , purple taproot carrot with purple petioles) through CRISPR/Cas9-based genome editing resulted in pale purple phenotype due to the dramatic decrease of anthocyanins content. DcMYB11c could induce the expression of DcbHLH3 and anthocyanins biosynthesis genes to jointly promote anthocyanins biosynthesis. Yeast one-hybrid assay (Y1H) and dual-luciferase reporter assay (LUC) revealed that DcMYB11c bound to the promoters of DcUCGXT1 and DcSAT1 and directly activated the expression of DcUCGXT1 and DcSAT1 responsible for anthocyanins glycosylation and acylation, respectively. Three transposons were present in the carrot cultivars with purple petioles but not in the carrot cultivars with green petioles. We revealed the core factor, DcMYB11c, involved in anthocyanins pigmentation in carrot purple petioles. This study provides new insights into precise regulation mechanism underlying anthocyanins biosynthesis in carrot. The orchestrated regulation mechanism in carrot might be conserved across the plant kingdom and useful for other researchers working on anthocyanins accumulation in different tissues.

ATF4 renders human T-cell acute lymphoblastic leukemia cell resistance to FGFR1 inhibitors through amino acid metabolic reprogramming.

Abnormalities of FGFR1 have been reported in multiple malignancies, suggesting FGFR1 as a potential target for precision treatment, but drug resistance remains a formidable obstacle. In this study, we explored whether FGFR1 acted a therapeutic target in human T-cell acute lymphoblastic leukemia (T-ALL) and the molecular mechanisms underlying T-ALL cell resistance to FGFR1 inhibitors. We showed that FGFR1 was significantly upregulated in human T-ALL and inversely correlated with the prognosis of patients. Knockdown of FGFR1 suppressed T-ALL growth and progression both in vitro and in vivo. However, the T-ALL cells were resistant to FGFR1 inhibitors AZD4547 and PD-166866 even though FGFR1 signaling was specifically inhibited in the early stage. Mechanistically, we found that FGFR1 inhibitors markedly increased the expression of ATF4, which was a major initiator for T-ALL resistance to FGFR1 inhibitors. We further revealed that FGFR1 inhibitors induced expression of ATF4 through enhancing chromatin accessibility combined with translational activation via the GCN2-eIF2α pathway. Subsequently, ATF4 remodeled the amino acid metabolism by stimulating the expression of multiple metabolic genes ASNS, ASS1, PHGDH and SLC1A5, maintaining the activation of mTORC1, which contributed to the drug resistance in T-ALL cells. Targeting FGFR1 and mTOR exhibited synergistically anti-leukemic efficacy. These results reveal that FGFR1 is a potential therapeutic target in human T-ALL, and ATF4-mediated amino acid metabolic reprogramming contributes to the FGFR1 inhibitor resistance. Synergistically inhibiting FGFR1 and mTOR can overcome this obstacle in T-ALL therapy.

Global analysis of the biosynthetic chemical space of marine prokaryotes.

BACKGROUND: Marine prokaryotes are a rich source of novel bioactive secondary metabolites for drug discovery. Recent genome mining studies have revealed their great potential to bio-synthesize novel secondary metabolites. However, the exact biosynthetic chemical space encoded by the marine prokaryotes has yet to be systematically evaluated. RESULTS: We first investigated the secondary metabolic potential of marine prokaryotes by analyzing the diversity and novelty of the biosynthetic gene clusters (BGCs) in 7541 prokaryotic genomes from cultivated and single cells, along with 26,363 newly assembled medium-to-high-quality genomes from marine environmental samples. To quantitatively evaluate the unexplored biosynthetic chemical space of marine prokaryotes, the clustering thresholds for constructing the biosynthetic gene cluster and molecular networks were optimized to reach a similar level of the chemical similarity between the gene cluster family (GCF)-encoded metabolites and molecular family (MF) scaffolds using the MIBiG database. The global genome mining analysis demonstrated that the predicted 70,011 BGCs were organized into 24,536 mostly new (99.5%) GCFs, while the reported marine prokaryotic natural products were only classified into 778 MFs at the optimized clustering thresholds. The number of MF scaffolds is only 3.2% of the number of GCF-encoded scaffolds, suggesting that at least 96.8% of the secondary metabolic potential in marine prokaryotes is untapped. The unexplored biosynthetic chemical space of marine prokaryotes was illustrated by the 88 potential novel antimicrobial peptides encoded by ribosomally synthesized and post-translationally modified peptide BGCs. Furthermore, a sea-water-derived Aquimarina strain was selected to illustrate the diverse biosynthetic chemical space through untargeted metabolomics and genomics approaches, which identified the potential biosynthetic pathways of a group of novel polyketides and two known compounds (didemnilactone B and macrolactin A 15-ketone). CONCLUSIONS: The present bioinformatics and cheminformatics analyses highlight the promising potential to explore the biosynthetic chemical diversity of marine prokaryotes and provide valuable knowledge for the targeted discovery and biosynthesis of novel marine prokaryotic natural products. Video Abstract.

Secondary Metabolic Potential of Kutzneria.

Kutzneria is a rare genus of Actinobacteria that harbors a variety of secondary metabolite gene clusters and produces several interesting types of bioactive secondary metabolites. Recent efforts have partially elucidated the biosynthetic pathways of some of these bioactive natural products, suggesting the diversity and specificity of secondary metabolism within this genus. Here, we summarized the chemical structures, biosynthetic pathways, and key metabolic enzymes of the secondary metabolites isolated from Kutzneria strains. In-depth comparative genomic analysis of all six available high-quality Kutzneria genomes revealed that the majority (77%) of the biosynthetic gene cluster families of Kutzneria were untapped and identified homologues of key metabolic enzymes in the putative gene clusters, including cytochrome P450s, halogenases, and flavin-dependent N-hydroxylases. The present study suggests that Kutzneria exhibits great potential to synthesize novel secondary metabolites, encodes a variety of valuable metabolic enzymes, and also provides valuable information for the targeted discovery and biosynthesis of novel natural products from Kutzneria.

Differential hydroxylation efficiency of the two non-heme carotene hydroxylases: DcBCH1, rather than DcBCH2, plays a major role in carrot taproot.

Carotene hydroxylase plays an important role in catalyzing the hydroxylation of carotene to xanthopylls, including two types: non-heme carotene hydroxylase (BCH type) and heme-containing cytochrome P450 hydroxylase (P450 type). Two BCH-encoding genes were annotated in the carrot genome. However, the role of BCHs and whether there are functional interactions between the duplicated BCHs in carrot remains unclear. In this study, two BCH encoding genes, DcBCH1 and DcBCH2, were cloned from carrot. The relative expression level of DcBCH1 was much higher than that of DcBCH2 in carrot taproots with different carotene accumulation levels. Overexpression of DcBCH1 in 'KRD' (high carotene accumulated) carrot changed the taproot color from orange to yellow, accompanied by substantial reductions in α-carotene and ß-carotene. There was no obvious change in taproot color between transgenic 'KRD' carrot overexpressing DcBCH2 and control carrot. Simultaneously, the content of α-carotene in the taproot of DcBCH2-overexpressing carrot decreased, but the content of ß-carotene did not change significantly in comparison with control carrot. Using the CRISPR/Cas9 system to knock out DcBCH1 in 'KRD' carrot lightened the taproot color from orange to pink-orange; the content of α-carotene in the taproot increased slightly, while the ß-carotene content was still significantly decreased, compared with control carrot. In DcBCH1-knockout carrot, the transcript level of DcBCH2 was significantly increased. These results indicated that in carrot taproot, DcBCH1 played the main function of BCH enzyme, which could hydroxylate α-carotene and ß-carotene; DcBCH1 and DcBCH2 had functional redundancy, and these two DcBCHs could partially compensate for each other.

Genome-Wide Identification and Evolution Analysis of R2R3-MYB Gene Family Reveals S6 Subfamily R2R3-MYB Transcription Factors Involved in Anthocyanin Biosynthesis in Carrot.

The taproot of purple carrot accumulated rich anthocyanin, but non-purple carrot did not. MYB transcription factors (TFs) condition anthocyanin biosynthesis in many plants. Currently, genome-wide identification and evolution analysis of R2R3-MYB gene family and their roles involved in conditioning anthocyanin biosynthesis in carrot is still limited. In this study, a total of 146 carrot R2R3-MYB TFs were identified based on the carrot transcriptome and genome database and were classified into 19 subfamilies on the basis of R2R3-MYB domain. These R2R3-MYB genes were unevenly distributed among nine chromosomes, and Ka/Ks analysis suggested that they evolved under a purified selection. The anthocyanin-related S6 subfamily, which contains 7 MYB TFs, was isolated from R2R3-MYB TFs. The anthocyanin content of rhizodermis, cortex, and secondary phloem in 'Black nebula' cultivar reached the highest among the 3 solid purple carrot cultivars at 110 days after sowing, which was approximately 4.20- and 3.72-fold higher than that in the 'Deep purple' and 'Ziwei' cultivars, respectively. The expression level of 7 MYB genes in purple carrot was higher than that in non-purple carrot. Among them, DcMYB113 (DCAR_008994) was specifically expressed in rhizodermis, cortex, and secondary phloem tissues of 'Purple haze' cultivar, with the highest expression level of 10,223.77 compared with the control 'DPP' cultivar at 70 days after sowing. DcMYB7 (DCAR_010745) was detected in purple root tissue of 'DPP' cultivar and its expression level in rhizodermis, cortex, and secondary phloem was 3.23-fold higher than that of secondary xylem at 110 days after sowing. Our results should be useful for determining the precise role of S6 subfamily R2R3-MYB TFs participating in anthocyanin biosynthesis in carrot.

Non-ribosomal peptide biosynthetic potential of the nematode symbiont Photorhabdus.

Photorhabdus, the symbiotic bacteria of Heterorhabditis nematodes, has been reported to possess many non-ribosomal peptide synthetase (NRPS) biosynthesis gene clusters (BGCs). To provide an in-depth assessment of the non-ribosomal peptide biosynthetic potential of Photorhabdus, we compared the distribution of BGCs in 81 Photorhabdus strains, confirming the predominant presence (44.80%) of NRPS BGCs in Photorhabdus. All 990 NRPS BGCs were clustered into 275 gene cluster families (GCFs) and only 13 GCFs could be annotated with known BGCs, suggesting their great diversity and novelty. These NRPS BGCs encoded 351 novel peptides containing more than four amino acids, and 173 of them showed high sequence similarity to known BGCs encoding bioactive peptides, implying the promising potential of Photorhabdus to produce valuable peptides. Sequence similarity networking of adenylation (A-) domains suggested that the substrate specificity of A-domains was not directly correlated with the sequence similarity. The molecular similarity network of predicted metabolite scaffolds of NRPS BGCs and reported peptides from Photorhabdus and a relevant database demonstrated that the non-ribosomal peptide biosynthetic potential of Photorhabdus was largely untapped and revealed the core peptides deserving intensive studies. Our present study provides valuable information for the targeted discovery of novel non-ribosomal peptides from Photorhabdus.

Aging Promotes Chronic Stress-Induced Depressive-Like Behavior by Activating NLRP1 Inflammasome-Driven Inflammatory Signaling in Mice.

NLRP1 inflammasome has been reported to participate in many neurological disorders. Our previous study has demonstrated that NLRP1 inflammasome is implicated in chronic stress-induced depressive-like behaviors in mice. Age has been reported to be related to depression. Here we examine whether NLRP1 inflammasome is involved in the effect of age on depressive disorder. Two chronic stress stimuli, chronic social defeat stress (CSDS) and repeat social defeat stress (RSDS), were used to establish a depression model in mice of different ages. We found that aged mice exhibited worse depressive-like behaviors and locomotor activity compared to young mice. Interestingly, the expression of hippocampal NLRP1 inflammasome complexes and the levels of the inflammatory cytokines were increased in an age-dependent manner. Also, chronic stress-induced increase in the expression of the hippocampal chemokine C-X-C motif ligand 1 (CXCL1), and its cognate receptor, CXC-motif receptor 2 (CXCR2), was more remarkable in aged mice than that in young mice. Moreover, aged mice exhibited lower hippocampal BDNF levels compared to young mice. Hippocampal Nlrp1a knockdown reduced the levels of pro-inflammatory cytokines and the expression of CXCL1/CXCR2, restored BDNF levels, and alleviated chronic stress-induced depressive-like behaviors in aged mice. Our results suggest that NLRP1 inflammasome-CXCL1/CXCR2-BDNF signaling contributes to the effect of age on chronic stress-induced depressive-like behavior in mice.

Saccharina japonica fucan suppresses high fat diet-induced obesity and enriches fucoidan-degrading gut bacteria.

Low molecular weight seaweed polysaccharides exhibit promising potential as novel therapeutics for the prevention of obesity and gut microbiota dysbiosis. The interplay between polysaccharides and gut microbiota may play crucial roles in their anti-obesity effects, but is largely unknown, including the impact of polysaccharides on the composition of the gut microbiota with polysaccharide-degrading capacity. The primary structure of a 5.1 kDa fucan (J2H) from Saccharina japonica was characterized and oral administration of J2H effectively suppressed high-fat diet-induced obesity, blood glucose metabolic dysfunction, dyslipidemia, and gut microbiota dysbiosis. Furthermore, the Jensen-Shannon divergence analysis demonstrated that J2H enriched at least four gut bacterial species with fucoidan-degrading potential, including Bacteroides sartorii and Bacteroides acidifaciens. Our findings suggest that the low molecular weight S. japonica fucan, J2H, is a promising potential agent for obesity prevention and its enrichment of gut bacteria with fucoidan-degrading potential may play a vital role in the anti-obesity effects.

AgGMP encoding GDP-D-mannose pyrophosphorylase from celery enhanced the accumulation of ascorbic acid and resistance to drought stress in Arabidopsis.

Ascorbic acid (AsA) is an important nutrient in celery, the conversion of D-mannose-1-P to GDP-D-mannose catalyzed by GDP-D-mannose pyrophosphorylase (GMPase) represents the first committed step in the biosynthesis of AsA. To clarify the function of the AgGMP gene of celery, the AgGMP gene was cloned from celery cv. 'Jinnan Shiqin' . It contains an open reading frame (ORF) with the length of 1,086 bp, encoding 361 amino acids. AgGMP protein was highly conserved among different plant species. Phylogenetic analysis demonstrated that the GMP proteins from celery and carrot belonged to the same branch. AgGMP protein was mainly composed of three α-helixes and certain random coils. No signal peptide was found in the AgGMP protein. The subcellular localization indicated that the AgGMP protein was located in the cytoplasm. The relative expression levels of AgGMP in 'Jinnan Shiqin' were significantly up-regulated at 2 h and 4 h under drought stress treatments. AsA contents in transgenic Arabidopsis lines hosting AgGMP gene were higher than that in wild type plants, and the root lengths were also longer in the MS medium containing 300 mM mannitol. The present study provides useful evidence for the functional involvement of AgGMP in regulating AsA accumulation and response to drought stress in celery.