Observation of Subdiffusive Dynamic Scaling in a Driven and Disordered Bose Gas.

We explore the dynamics of a tuneable box-trapped Bose gas under strong periodic forcing in the presence of weak disorder. In absence of interparticle interactions, the interplay of the drive and disorder results in an isotropic nonthermal momentum distribution that shows subdiffusive dynamic scaling, with sublinear energy growth and the universal scaling function captured well by a compressed exponential. We explain that this subdiffusion in momentum space can naturally be understood as a random walk in energy space. We also experimentally show that for increasing interaction strength, the gas behavior smoothly crosses over to wave turbulence characterized by a power-law momentum distribution, which opens new possibilities for systematic studies of the interplay of disorder and interactions in driven quantum systems.

Functional testing is a complementary tool for the diagnosis of vaginitis.

OBJECTIVE: Vaginal microbiota evaluation is a methodology widely used in China to diagnose various vaginal inflammatory diseases. Although vaginal microbiota evaluation has many advantages, it is time-consuming and requires highly skilled and experienced operators. Here, we investigated a six-index functional test that analyzed pH, hydrogen peroxide (H2O2), leukocyte esterase (LEU), sialidase (SNA), ß-glucuronidase (GUS), and acetylglucossidase (NAG), and determined its diagnostic value by comparing it with morphological tests of vaginal microbiota. MATERIALS AND METHODS: The research was conducted using data extracted from the Laboratory Information System of Women and Children's Hospital. A total of 4902 subjects, ranging in age from 35.4 ± 9.7 years, were analyzed. During the consultation, a minimum of two vaginal swab specimens per patient were collected for both functional and morphological testing. Fisher's exact was used to analyze data using SPSS. RESULTS: Of the 4,902 patients, 2,454 were considered to have normal Lactobacillus morphotypes and 3,334 were considered to have normal dominant microbiota. The sensitivity and specificity of H2O2-indicating Lactobacillus morphotypes were 91.3% and 25.28%, respectively, while those of pH-indicating Lactobacillus morphotypes were 88.09% and 59.52%, respectively. The sensitivity and specificity of H2O2-indicating dominant microbiota were 91.3% and 25.3%, respectively, while those of pH-indicating dominant microbiota were 86.27% and 64.45%, respectively. The sensitivity and specificity of NAG for vulvovaginal candidiasis were 40.64% and 84.8%, respectively. For aerobic vaginitis, GUS sensitivity was low at 0.52%, while its specificity was high at 99.93%; the LEU sensitivity and specificity values were 94.73% and 27.49%, respectively. Finally, SNA sensitivity and specificity for bacterial vaginosis were 80.72% and 96.78%, respectively. CONCLUSION: Functional tests (pH, SNA, H2O2, LEU) showed satisfactory sensitivity for the detection of vaginal inflammatory diseases. However, these tests lacked specificity, making it difficult to accurately identify specific pathologies. By contrast, NAG and GUS showed excellent specificity in identifying vaginal inflammatory diseases, but their sensitivity was limited. Therefore, functional tests alone are not sufficient to diagnose various vaginal inflammatory diseases. When functional and morphological tests are inconsistent, morphological tests are currently considered the preferred reference method.

Identification of P450 Candidates Associated with the Biosynthesis of Physalin-Class Compounds in Physalis angulata.

The Physalis genus has long been used as traditional medicine in the treatment of various diseases. Physalins, the characteristic class of compounds in this genus, are major bioactive constituents. To date, the biogenesis of physalins remains largely unknown, except for the recently established knowledge that 24-methyldesmosterol is a precursor of physalin. To identify the genes encoding P450s that are putatively involved in converting 24-methyldesmosterol to physalins, a total of 306 P450-encoding unigenes were retrieved from our recently constructed P. angulata transcriptome. Extensive phylogenetic analysis proposed 21 P450s that might participate in physalin biosynthesis. To validate the candidates, we developed a virus-induced gene silencing (VIGS) system for P. angulata, and four P450 candidates were selected for the VIGS experiments. The reduction in the transcripts of the four P450 candidates by VIGS all led to decreased levels of physalin-class compounds in the P. angulata leaves. Thus, this study provides a number of P450 candidates that are likely associated with the biosynthesis of physalin-class compounds, forming a strong basis to reveal the unknown physalin biosynthetic pathway in the future.

Serum metabolomics analysis of biomarkers and metabolic pathways in patients with colorectal cancer associated with spleen-deficiency and qi-stagnation syndrome or damp-heat syndrome: a prospective cohort study.

Objective: To profile the serum metabolites and metabolic pathways in colorectal cancer (CRC) patients associated with spleen-deficiency and qi-stagnation syndrome (SDQSS) or damp-heat syndrome (DHS). Methods: From May 2020 to January 2021, CRC patients diagnosed with traditional Chinese medicine (TCM) syndromes of SDQSS or DHS were enrolled. The clinicopathological data of the SDQSS and DHS groups were compared. The serum samples were analyzed by liquid chromatography-mass spectrometry (LC-MS). The variable importance in the projection >1, fold change ≥3 or ≤0.333, and P value ≤0.05 were used to identify differential metabolites between the two groups. Furthermore, areas under the receiver operating characteristic (ROC) curve > 0.9 were applied to select biomarkers with good predictive performance. The enrichment metabolic pathways were searched through the database of Kyoto Encyclopedia of Genes and Genomes. Results: 60 CRC patients were included (30 SDQSS and 30 DHS). The level of alanine aminotransferase was marginally significantly higher in the DHS group than the SDQSS group (P = 0.051). The other baseline clinicopathological characteristics were all comparable between the two groups. 23 differential serum metabolites were identified, among which 16 were significantly up-regulated and 7 were significantly down-regulated in the SDQSS group compared with the DHS group. ROC curve analysis showed that (S)-3-methyl-2-oxopentanoic acid, neocembrene, 1-aminocyclopropanecarboxylic acid, 3-methyl-3-hydroxypentanedioate, and nicotine were symbolic differential metabolites with higher predictive power. The top five enrichment signalling pathways were valine, leucine and isoleucine biosynthesis; lysosome; nicotine addiction; fructose and mannose metabolism; and pertussis. Conclusion: Our study identifies the differential metabolites and characteristic metabolic pathways among CRC patients with SDQSS or DHS, offering the possibility of accurate and objective syndrome differentiation and TCM treatment for CRC patients.

Injectable chitosan/xyloglucan composite hydrogel with mechanical adaptivity and endogenous bioactivity for skin repair.

Delayed or chronic wound healing is one of severe clinical issues. Developing scaffold materials capable of supporting cells and inducing tissue regeneration remains a challenge. Here, a polysaccharide-based hydrogel is constructed for promoting full-thickness skin wound healing in mouse model. The engineering hydrogel consists of a dynamic crosslinking network formed by the Schiff base reaction between aldehyde-containing xyloglucan and methacrylated chitosan. Its reversible gel-sol-gel transition upon shearing force is highly beneficial to completely cover and fill irregular wound shape. The second covalent cross-linking network achieved by photo-initiated polymerization offers a feasible way to tune the mechanical property of hydrogel after injection, with an ideal mechanical adaptivity for clinical application. Remarkably, both in vitro and in vivo evaluations demonstrate that the hydrogel with endogenously bioactive galactoside units can promote cell spheroid formation and accelerate wound healing by expediting re-epithelialization, collagen deposition, angiogenesis as well as the formation of hair follicles.

Genome-wide identification and expression pattern analysis of R2R3-MYB transcription factor gene family involved in puerarin biosynthesis and response to hormone in Pueraria lobata var. thomsonii.

BACKGROUND: R2R3-MYB transcription factors regulate secondary metabolism, stress responses and development in various plants. Puerarin is a bioactive ingredient and most abundant secondary metabolite isolated from Pueraria lobata. The biosynthesis of puerarin proceeds via the phenylpropanoid pathway and isoflavonoids pathway, in which 9 key enzymes are involved. The expression of these structural genes is under control of specific PtR2R3-MYB genes in different plant tissues. However, how PtR2R3-MYB genes regulates structural genes in puerarin biosynthesis remains elusive. This study mined the PtR2R3-MYB genes involved in puerarin biosynthesis and response to hormone in Pueraria lobata var. thomsonii. RESULTS: A total of 209 PtR2R3-MYB proteins were identified, in which classified into 34 subgroups based on the phylogenetic topology and the classification of the R2R3-MYB superfamily in Arabidopsis thaliana. Furtherly physical and chemical characteristics, gene structure, and conserved motif analysis were also used to further analyze PtR2R3-MYBs. Combining puerarin content and RNA-seq data, speculated on the regulated puerarin biosynthesis of PtR2R3-MYB genes and structural genes, thus 21 PtR2R3-MYB genes and 25 structural genes were selected for validation gene expression and further explore its response to MeJA and GSH treatment by using qRT-PCR analysis technique. Correlation analysis and cis-acting element analysis revealed that 6 PtR2R3-MYB genes (PtMYB039, PtMYB057, PtMYB080, PtMYB109, PtMYB115 and PtMYB138) and 7 structural genes (PtHID2, PtHID9, PtIFS3, PtUGT069, PtUGT188, PtUGT286 and PtUGT297) were directly or indirectly regulation of puerarin biosynthesis in ZG11. It is worth noting that after MeJA and GSH treatment for 12-24 h, the expression changes of most candidate genes were consistent with the correlation of puerarin biosynthesis, which also shows that MeJA and GSH have the potential to mediate puerarin biosynthesis by regulating gene expression in ZG11. CONCLUSIONS: Overall, this study provides a comprehensive understanding of the PtR2R3-MYB and will paves the way to reveal the transcriptional regulation of puerarin biosynthesis and response to phytohormone of PtR2R3-MYB genes in Pueraria lobata var. thomsonii.

Comparative Transcriptome Analysis of Pueraria lobata Provides Candidate Genes Involved in Puerarin Biosynthesis and Its Regulation.

Pueraria lobata is a traditional Chinese herb in which an isoflavone C-glucoside, namely puerarin, has received the utmost interest due to its medicinal properties. To date, the biogenesis of puerarin, especially its C-glucosyl reaction in the pathway, remains poorly understood. Moreover, the transcription factors (TFs) that regulate puerarin biosynthesis in P. lobata have not been reported. Here, we performed phytochemical studies on the different developmental stages of the root, stem, and leaf tissues of two P. lobata cultivars, which suggested that both the roots and stems of P. lobata were the sites of puerarin biosynthesis. RNA-sequencing was conducted with the root and stem tissues of the two cultivars under different stages, and the clean reads were mapped to the recently published genome of P. lobata var. thomsonii, yielding the transcriptome dataset. A detailed analysis of the gene expression data, gene coexpression network, and phylogeny proposed several C-GTs that likely participate in puerarin biosynthesis. The first genome-wide analysis of the whole MYB superfamily in P. lobata presented here identified a total of 123 nonredundant PlMYB genes that were significantly expressed in the analyzed tissues. The phylogenetic analysis of PlMYBs with other plant MYB proteins revealed strong PlMYB candidates that may regulate the biosynthesis of isoflavones, such as puerarin.

Transmission-based charge modulation microscopy on conjugated polymer blend field-effect transistors.

Charge modulation microscopy (CMM) is an electro-optical method that is capable of mapping the spatial distribution of induced charges in an organic field-effect transistor (OFET). Here, we report a new (and simple) implementation of CMM in transmission geometry with camera-based imaging. A significant improvement in data acquisition speed (by at least an order of magnitude) has been achieved while preserving the spatial and spectral resolution. To demonstrate the capability of the system, we measured the spatial distribution of the induced charges in an OFET with a polymer blend of indacenodithiophene-co-benzothiadiazole and poly-vinylcarbazole that shows micrometer-scale phase separation. We were able to resolve spatial variations in the accumulated charge density on a length scale of 500 nm. We demonstrated through a careful spectral analysis that the measured signal is a genuine charge accumulation signal that is not dominated by optical artifacts.

Glycosylation and methylation in the biosynthesis of isoflavonoids in Pueraria lobata.

The pathway for forming isoflavonoid skeletal structure is primarily restricted to the Leguminosae family. Subsequent decorations on the compound backbone by tailoring enzymes would change their biological and medicinal properties. Pueraria lobata is a leguminous plant, and as a traditional Chinese medicine its roots have been ascribed a number of pharmacological activities. Glycosylation and methylation are the main modifying processes in isoflavonoid metabolism in P. lobata roots, resulting in the accumulation of unique glycosylated and methylated end isoflavonoid compounds. For instance, daidzein 8-C-glucoside (i.e., puerarin) and puerarin derivatives are produced only by the Pueraria genus. Puerarin has been established as a clinical drug for curing cardiovascular diseases. To better understand the characteristic isoflavonoid metabolism in P. lobata, this review attempts to summarize the research progress made with understanding the main glycosylation and methylation of isoflavonoids in P. lobata and their biosynthetic enzymes.

RNAi of Sterol Δ24-Isomerase Implicated Its Involvement in Physalin Biosynthesis in Physalis angulata L.

Physalis angulata is a renowned traditional Chinese medicine for the treatment of various conditions. Physalin is the major type of bioactive constituents conferring medicinal properties of P. angulata. Despite the medicinal importance, the pathways leading to physalin are largely unknown. In this study, we employed a transcriptomic approach to identify a Pa24ISO gene from P. angulata. Through heterologous expression in yeast, Pa24ISO was revealed to catalyze an isomerization reaction in converting 24-methylenecholesterol to 24-methyldesmosterol. Real-time PCR analysis showed that the abundance of Pa24ISO transcripts correlated with the accumulation pattern of physalin B in different tissues of P. angulata. A direct role of Pa24ISO in channeling of 24-methylenecholesterol for physalin B biosynthesis was illustrated by suppressing the gene in P. angulata via the VIGS approach. Down-regulation of Pa24ISO led to reduced levels of 24-methyldesmosterol and physalin B, accompanied with an increase of campesterol content in P. angulata. The results supported that 24ISO is involved in physalin biosynthesis in plants.

A Composite Deferoxamine/Black Phosphorus Nanosheet/Gelatin Hydrogel Scaffold for Ischemic Tibial Bone Repair.

Introduction: Bone delay union is mostly caused by lack of blood supply. Although autografts, allografts and artificial bone have been widely used to treat bone delay union, the bone regeneration fails in the ischemic site accompanied by the bone donor site complications and disease transmission. Recently, there is a growing recognition of the importance of hydrogel scaffolds which are regarded as an eligible engineer tissue for bone repair. However, hydrogel is still limited in improving neovascularization. Methods: In this work, black phosphorus nanosheet and deferoxamine (BPN-DFO) were loaded in the gelatin hydrogel to overcome the high risk of bone delay union and systemically investigated the regeneration capability of BPN-DFO hydrogel in vitro and vivo. Results: The resulting BPN-DFO hydrogel scaffold showed superior swollen, degradation and release rate, as well as satisfied biocompatibility. BPN-DFO hydrogel shown the significant up-expression of mRNA related to bone regeneration and cell proliferation. In vivo, the proposed BPN-DFO hydrogel significantly improved osteogenesis and neovascularization in the ischemic tibial bone site of SD rats with acute femoral artery occlusion. Both macroscopic and histological evaluation of new regenerated bone showed newly formed blood vessel and collagen using BPN-DFO hydrogel. The immunohistochemistry and RT-PCR revealed that the bone regeneration could be improved via BMP/Runx2 pathway. Conclusion: The BPN-DFO hydrogel possesses potential tissue engineer material for ischemic bone defect treatment. However, furthermore studies are needed to testify the safety and efficacy of BPN-DFO hydrogel.

Antimicrobial Lignin-Based Polyurethane/Ag Composite Foams for Improving Wound Healing.

Antimicrobial materials are an urgent need for modern wound care in the clinic. Although traditional polyurethane foams have proven to be clinically valuable for wound treatment, their petroleum-originated preparation and bioinert nature have restricted their efficacy in biomedical applications. Here, we propose a simple one-step foaming method to prepare lignin-based polyurethane foams (LPUFs) in which fully biobased polyether polyols partially replace traditional petroleum-based raw materials. The trace amount of phenolic hydroxyl groups (about 4 mmol) in liquefied lignin acts as a direct reducing agent and capping agent to silver ions (less than 0.3 mmol), in situ forming silver nanoparticles (Ag NPs) within the LPUF skeleton. This newly proposed lignin polyurethane/Ag composite foam (named as Ag NP-LPUF) shows improved mechanical, thermal, and antibacterial properties. It is worth mentioning that the Ag NP-LPUF exhibits more than 99% antibacterial rate against Escherichia coli within 1 h and Staphylococcus aureus within 4 h. Evaluations in mice indicate that the antimicrobial composite foams can effectively promote wound healing of full-thickness skin defects. As a proof of concept, this antibacterial and biodegradable foam exhibits significant potential for clinical translation in wound care dressings.

Symmetric positive definite manifold learning and its application in fault diagnosis.

Locally linear embedding (LLE) is an effective tool to extract the significant features from a dataset. However, most of the relevant existing algorithms assume that the original dataset resides on a Euclidean space, unfortunately nearly all the original data space is non-Euclidean. In addition, the original LLE does not use the discriminant information of the dataset, which will degrade its performance in feature extraction. To address these problems raised in the conventional LLE, we first employ the original dataset to construct a symmetric positive definite manifold, and then estimate the tangent space of this manifold. Furthermore, the local and global discriminant information are integrated into the LLE, and the improved LLE is operated in the tangent space to extract the important features. We introduce Iris dataset to analyze the capability of the proposed method to extract features. Finally, several experiments are performed on five machinery datasets, and experimental results indicate that our proposed method can extract the excellent low-dimensional representations of the original dataset. Compared with the state-of-the-art methods, the proposed algorithm shows a strong capability for fault diagnosis.

Chromosomal-level genome and multi-omics dataset of Pueraria lobata var. thomsonii provide new insights into legume family and the isoflavone and puerarin biosynthesis pathways.

Pueraria lobata var. thomsonii (hereinafter abbreviated as Podalirius thomsonii), a member of legumes, is one of the important traditional Chinese herbal medicines, and its puerarin extraction is widely used in health and pharmaceutical industry. Here, we assembled a high-quality genome of P. thomsonii using long-read single-molecule sequencing and Hi-C technologies. The genome assembly is approximately 1.37 Gb in size and consists of 5145 contigs with a contig N50 of 593.70 Kb, further clustered into 11 pseudochromosomes. The genome structural annotation resulted in about 869.33 Mb (about 62.70% of the genome) repeat regions and 45 270 protein-coding genes. Genome evolution analysis revealed that P. thomsonii is most closely related to soybean and underwent two ancient whole-genome duplication events, one was in the common ancestor shared by legume species, the other occurred independently at around 7.2 million years ago after its specification. A total of 2373 gene families were found unique in P. thomsonii comparing to five other legume species. Genes and metabolites related to puerarin content in tuberous tissues were characterized. A total of 572 genes upregulated in the puerarin biosynthesis pathway were identified, and 235 candidate genes were further enriched by omics data. Furthermore, we identified 6 8-C-glucosyltransferase (8-C-GT) candidate genes significantly involved in puerarin metabolism. Our study filled in a key genomic gap in legume family, and provided valuable multi-omic resources for the genetic improvement of P. thomsonii.

22R- but not 22S-hydroxycholesterol is recruited for diosgenin biosynthesis.

Diosgenin is an important compound in the pharmaceutical industry and it is biosynthesized in several eudicot and monocot species, herein represented by fenugreek (a eudicot), and Dioscorea zingiberensis (a monocot). Formation of diosgenin can be achieved by the early C22,16-oxidations of cholesterol followed by a late C26-oxidation. This study reveals that, in both fenugreek and D. zingiberensis, the early C22,16-oxygenase(s) shows strict 22R-stereospecificity for hydroxylation of the substrates. Evidence against the recently proposed intermediacy of 16S,22S-dihydroxycholesterol in diosgenin biosynthesis was also found. Moreover, in contrast to the eudicot fenugreek, which utilizes a single multifunctional cytochrome P450 (TfCYP90B50) to perform the early C22,16-oxidations, the monocot D. zingiberensis has evolved two separate cytochrome P450 enzymes, with DzCYP90B71 being specific for the 22R-oxidation and DzCYP90G6 for the C16-oxidation. We suggest that the DzCYP90B71/DzCYP90G6 pair represent more broadly conserved catalysts for diosgenin biosynthesis in monocots.

Psychological Impact of COVID-19 Epidemic on Adolescents: A Large Sample Study in China.

Background: The COVID-19 pandemic is a major public health emergency. However, little is known about the psychological impact of this pandemic on adolescents. We aim to assess the prevalence and influencing factors of depression, anxiety, and posttraumatic growth (PTG) among adolescents in a large sample study. Methods: This cross-sectional study collected demographic data and mental health measurements from 175,416 adolescents covering 31 provinces, centrally administered municipalities, and autonomous regions in mainland China from February 23 to March 8, 2020. The status of depression, anxiety, and PTG was assessed by the nine-item Patient Health Questionnaire, seven-item generalized anxiety disorder questionnaire, and post-traumatic growth inventory. Results: The prevalence of depression, anxiety, and PTG in adolescents was 35.9, 28.0, and 45.6%, respectively. The prevalence of depression and anxiety in the slight or severe epidemic areas was similar. Regression analysis showed that female sex and older age were associated with higher levels of depression, anxiety, and lower levels of PTG. Symptoms related to COVID-19, excessive attention to epidemic information, living in urban or severe epidemic areas, and conflicts with parents during home quarantine were risk factors for depression, anxiety, and PTG. Frequent communication with peers, exercise, and receiving public welfare psychological assistance were protective factors. Poor family economic status was a significant risk factor for depression and PTG. Conclusion: Our findings suggested that positive and negative psychological reactions coexist in adolescents faced with the pandemic. The factors associated with psychological problems and PTG provide strategic guidance for maintaining adolescents' mental health in China and worldwide during any pandemic such as COVID-19.

Hydrogels with tunable modulus regulate chondrocyte microaggregates growth for cartilage repair.

Chondrocyte spheroids in 3D hydrogel are more beneficial to improve their survival and maintain chondrogenic phenotype comparing to dissociated chondrocytes. However,in-situinducing cell into spheroids rather than encapsulating spheroids in a hydrogel remains a tremendous challenge because of the limitations of biochemical and viscoelastic controllability for hydrogel. Herein, a hydrogel consisting of photo-crosslinkable chitosan methacrylate (CHMA) and semi-interpenetrating polyvinyl alcohol (PVA) is developed as a cell-responsive matrix with controllable viscoelastic properties. The proposed CHMA-PVA precursor preferentially exhibits a weak gel-like state with a storage modulus of 16.9 Pa, loss modulus of 13.0 Pa and yielding stain of 1%, which could allow chondrocyte to vigorously move and assemble but hinder their precipitation before crosslinking. The chondrocytes could form microaggregates within 8 hin vitroand keep high viability. Moreover, subcutaneous implantation experiments demonstrate that the CHMA/PVA hydrogels are biocompatible and degrade within five weeksin vivo. The cell-free hydrogels are further placed in cylindrical cartilage defects in the rabbit femoral condyle and examined 8 weeks postoperatively. Gross, histological and immunohistochemical analyses reveal a significant acceleration for the cartilage regeneration. These findings suggest that this novel cell adhesion-responsive and histo-compatible hydrogel is promising for cartilage regeneration.

Molecular Cloning and Functional Characterization of a Sterol 3-O-Glucosyltransferase Involved in Biosynthesis of Steroidal Saponins in Trigonella foenum-graecum.

Fenugreek (Trigonella foenum-graecum), a pharmacologically important herb, is widely known for its antidiabetic, hypolipidemic, and anticancer effects. The medicinal properties of this herb are accredited to the presence of bioactive steroidal saponins with one or more sugar moieties linked to the C-3 OH position of disogenin or its C25-epimer yamogenin. Despite intensive studies regarding pharmacology and phytochemical profiles of this plant, enzymes and/or genes involved in synthesizing the glycosidic part of fenugreek steroidal saponins are still missing so far. This study reports the molecular cloning and functional characterization of a key sterol-specific glucosyltransferase, designated as TfS3GT2 here, from fenugreek plant. The recombinant TfS3GT2 was purified via expression in Escherichia coli, and biochemical characterization of the recombinant enzyme suggested its role in transferring a glucose group onto the C-3 hydroxyl group of diosgenin or yamogenin. The functional role of TfS3GT2 in the steroidal saponin biosynthesis was also demonstrated by suppressing the gene in the transgenic fenugreek hairy roots via the RNA interference (RNAi) approach. Down-regulation of TfS3GT2 in fenugreek generally led to reduced levels of diosgenin or yamogenin-derived steroidal saponins. Thus, Tf3SGT2 was identified as a steroid-specific UDP-glucose 3-O-glucosyltransferase that appears to be involved in steroidal saponin biosynthesis in T. foenum-graecum.

Altering Sterol Composition Implied That Cholesterol Is Not Physiologically Associated With Diosgenin Biosynthesis in Trigonella foenum-graecum.

Diosgenin serves as an important precursor of most steroidal drugs in market. Cholesterol was previously deemed as a sterol origin leading to diosgenin biosynthesis. This study reports that cholesterol is not in parallel with diosgenin biosynthesis in Trigonella foenum-graecum. We first perturbed its sterol composition using inhibitors specific for the upstream isoprenoid pathway enzymes, HMGR (3-hydroxy-3-methylgutaryl-CoA reductase) on the mevalonate (MVA) and DXR (1-deoxy-D-xylulose-5-phosphate reductoisomerase) on the 2-C-methyl-D-erythritol-4-phophate (MEP) pathways, and have revealed that diosgenin and cholesterol reversely or differently accumulated in either the MVA or the MEP pathway-suppressed plants, challenging the previously proposed role of cholesterol in diosgenin biosynthesis. To further investigate this, we altered the sterol composition by suppressing and overexpressing the 24-sterol methyltransferase type 1 (SMT1) gene in T. foenum-graecum, as SMT1 acts in the first committed step of diverting the carbon flux of cholesterol toward biosynthesis of 24-alkyl sterols. Knockdown of TfSMT1 expression led to increased cholesterol level but caused a large reduction of diosgenin. Diosgenin was increased upon the TfSMT1-overexpressing, which, however, did not significantly affect cholesterol biosynthesis. These data consistently supported that diosgenin biosynthesis in T. foenum-graecum is not associated with cholesterol. Rather, campesterol, a 24-alkyl sterol, was indicative of being correlative to diosgenin biosynthesis in T. foenum-graecum.