Search Results (46)

The flea-borne transmission of Yersinia pestis relies on biofilm formation and metabolic adaptation within the insect gut. The pentose phosphate pathway (PPP) is central to these processes, yet the contribution of its non-oxidative branch remains poorly defined. Here, we investigated the roles of transketolase (TktA) and transaldolase (TalB) in plague bacillus physiology, metabolism, and flea colonization. TktA was essential for growth, preventing assessment of its role in biofilm formation and in vivo colonization. In contrast, TalB was dispensable for growth but required for optimal biofilm formation. In fleas, the ΔtalB mutant colonized the proventriculus but displayed a lower bacterial load than the wild-type strain at later time points, indicating a defect in sustained colonization. Metabolomic analyses revealed that disruption of tktA severely impairs PPP-associated metabolism, whereas loss of talB is associated with disruption of nucleotide homeostasis, carbon redistribution toward glycolysis, and a redox imbalance. These findings demonstrate a functional partitioning of the non-oxidative PPP and identify it as a key metabolic control node linking metabolism to colonization dynamics in Y. pestis. Full article

Acute kidney injury (AKI) lacks targeted pharmacological interventions. While the DanShen–DaHuang (DS-DH) herb pair shows clinical potential for AKI treatment, and our prior study has validated its nephroprotective efficacy in a cisplatin-induced murine model, its specific molecular targets within the renal microenvironment remain undefined. In this study, we integrated network pharmacology and weighted gene co-expression network analysis (WGCNA) to screen AKI-related targets of the DS-DH pair. A multi-algorithmic machine learning pipeline (including LASSO, Boruta, Random Forest, GBM, XGBoost, and Decision Trees) was utilized to calculate feature importance scores and rank core genes. Subsequently, single-cell RNA sequencing (scRNA-seq) data (GSE197266) were analyzed for transcriptomic mapping, pseudotime trajectory, and cell–cell communication. Finally, molecular docking evaluated theoretical binding affinities. After database screening, a total of 603 drug–disease intersecting targets were obtained. Subsequently, 917 module genes significantly associated with AKI were identified by WGCNA, and 62 core candidate genes were determined after intersecting with the above targets. Multi-algorithm machine learning ranked the importance of the 62 targets, with transketolase (TKT) ranking the highest. To elucidate the mechanism of TKT in AKI, scRNA-seq analysis was performed on 77,593 high-quality cells. The results showed that Tkt was specifically enriched in renal macrophages, with the highest expression in the M2-polarized subset. Pseudotime analysis further revealed that Tkt expression dynamics were highly synchronized with the differentiation trajectory of M2 macrophages and positively correlated with the repair markers Arg1 and Mrc1. Cell–cell communication analysis predicted that Tkt⁺ M2 macrophages act as active communication hubs via the Spp1 and Mif signaling axes. Molecular docking validated the favorable binding affinity between core DS-DH compounds and the TKT active pocket. This computational framework predicts that the DS-DH herb pair might mitigate AKI by potentially targeting TKT, a metabolic enzyme closely associated with macrophage M2 polarization. By prioritizing targets via multi-algorithmic scoring, we provide a data-driven rationale and candidate targets for future experimental validation. Full article

Background: Diabetic peripheral neuropathy (DPN) affects up to 50% of diabetes patients and is driven by hyperglycemia-induced oxidative stress, mitochondrial dysfunction, polyol pathway activation, advanced glycation end-product formation, and inflammation. Current management is largely symptomatic, prompting interest in metabolic/nutritional therapies. This review critically evaluates the mechanistic rationale and clinical evidence for alpha-lipoic acid (ALA) and benfotiamine as adjunctive treatments for DPN. Methods: A structured narrative review of PubMed/MEDLINE was conducted using predefined keywords for DPN, oxidative stress, metabolic therapy, and thiamine derivatives. Randomized controlled trials, clinical studies, systematic reviews, and relevant experimental studies were included. Evidence was synthesized qualitatively with emphasis on mechanistic plausibility, clinical efficacy, intervention duration, and methodological rigor. Results: ALA consistently improves short-term symptoms across multiple randomized trials. The long-term NATHAN 1 trial reported a marginal, borderline significant effect on the primary composite endpoint (NIS-LL, p = 0.05) without significant improvements in nerve conduction studies; therefore, evidence for functional stabilization is very limited and inconclusive. ALA’s effects are attributed to antioxidant activity, mitochondrial protection, and improved microvascular function. Benfotiamine has a strong biochemical rationale (transketolase activation, diversion of glycolytic intermediates from damaging pathways), but clinical evidence remains limited to short-duration, symptom-based studies, with no large-scale, long-term trials published. Conclusions: Both agents target key pathways in DPN pathogenesis. ALA is the most established adjunctive metabolic therapy for symptomatic DPN, although no study has demonstrated structural nerve regeneration or a definitive disease-modifying effect. Benfotiamine is biologically plausible but requires further validation in long-term randomized trials with structural and biomarker-based endpoints. Outside of documented thiamine deficiency, its routine use cannot be recommended based on current evidence. Full article

Water deficit (WD) irrigation has garnered considerable attention for its potential to enhance crop water use efficiency. However, limited research has been conducted on its ability to improve tomato fruit sweetness-related traits without significantly affecting yield. In this study, we investigated the effects of varying WD levels [T1–T4: 80%, 65%, 55%, and 45% of field capacity (FC)] compared with full irrigation (CK: 90% FC) on tomato fruits from the mature green to red-ripe stages, aiming to evaluate yield, textural attributes, and sugar composition. Notably, the fruit yield per plant under T2 treatment was not significantly different from that under CK. Compared with CK, T2 significantly reduced fruit water content by 2.39% while markedly increasing individual fruit dry weight by 13.61%. At 44 days after flowering, fruit firmness under T2 showed no substantial difference from CK, whereas adhesiveness was markedly elevated by 33.85%. Furthermore, T2 substantially boosted the activities of key Calvin cycle enzymes (ribulose-1,5-bisphosphate carboxylase/oxygenase, glyceraldehyde-3-phosphate dehydrogenase, fructose-1,6-bisphosphatase, fructose-1,6-bisphosphate aldolase, and transketolase) in tomato leaves, thereby increasing the photosynthetic rate and consequently elevating the total sugar content in tomato fruits. Additionally, T2 stimulated the activities of sucrose-hydrolyzing enzymes (acid invertase and neutral invertase) in fruits, leading to increased fructose and glucose accumulation at the red-ripening stage, with respective increases of 69.60% and 34.67% relative to CK. Multivariate classification based on principal component analysis and hierarchical cluster analysis revealed that T2 and T3 were distinctly separated from other treatments in terms of yield, texture parameters, and sugar profiles. These findings provide a valuable strategy for applying WD to improve fruit sugar composition without compromising yield. Full article

Thiamine (vitamin B1) and its phosphates are essential for almost all organisms. Thiamine diphosphate (ThDP) is the major intracellular derivative which is considered the only form functioning as a coenzyme. Thiamine triphosphate (ThTP), another ubiquitous derivative, lacks a clear physiological function and is usually kept at low levels. However, it can accumulate up to 87% of total thiamine in animal tissues lacking cytosolic thiamine triphosphatase (THTPA) activity. Studies of ThTP coenzyme function have always faced the problem of ThTP hydrolysis to ThDP. To avoid such interference a synthetic stable ThTP analog, bismethylene ThTP (bmThTP), has been synthesized. Given that ThTP accumulation is caused by cytosolic THTPA suppression, cytosolic ThDP-dependent transketolase (TKT) is the primary target for probing (bm)ThTP’s coenzyme function. Indeed, bmThTP acts as a TKT coenzyme, with the apparent K_m(bmThTP) of 16.3 µM. However, bmThTP binding slightly differs from that of ThTP. Molecular docking was used to estimate affinities of ThDP, ThTP and bmThTP, also allowing us to avoid ThTP hydrolysis. Despite almost identical localization within the active site, bmThTP could not bind as well as ThTP, resulting in a 2.36 kcal/mol difference in estimated ΔG. Based on our data, calculated K_m(ThTP) for TKT is about 0.07–0.08 µM, only 1.6–2 times that of K_m(ThDP). Such a small difference implies that ThTP could physiologically act as the main TKT coenzyme form upon its accumulation in muscles, at least in a few known animal species. Full article

Diabetic ketoacidosis (DKA) remains a life-threatening complication of diabetes mellitus with suboptimal outcomes despite standard management. Emerging evidence suggests that thiamine (vitamin B1) deficiency may play an under-recognized role in DKA pathophysiology and clinical course. This narrative review synthesizes current evidence regarding thiamine deficiency in diabetes and DKA, examining molecular mechanisms, clinical implications, and the rationale for thiamine supplementation as adjunctive therapy. Thiamine deficiency is highly prevalent in diabetes, with plasma concentrations reduced by approximately 75% compared to healthy controls. In DKA specifically, 25–35% of patients present with thiamine deficiency, which often worsens during insulin therapy. The primary mechanism involves hyperglycemia-induced downregulation of renal thiamine transporters (THTR-1 and THTR-2), resulting in 16–24-fold increased renal clearance and massive urinary losses. Thiamine pyrophosphate serves as an essential cofactor for three critical enzymes in glucose metabolism: pyruvate dehydrogenase, α-ketoglutarate dehydrogenase, and transketolase. Deficiency impairs these pathways, causing pyruvate accumulation with conversion to lactate (resulting in lactic acidosis), compromised TCA cycle function (reducing ATP production by 40–48%), and decreased NADPH generation (increasing oxidative stress). Clinical manifestations include persistent metabolic acidosis despite standard therapy, myocardial dysfunction with elevated cardiac biomarkers, neurological impairment, and prolonged recovery times. Cellular studies demonstrate that thiamine supplementation significantly improves mitochondrial oxygen consumption in DKA patients. The high prevalence of thiamine deficiency in DKA, compelling biochemical rationale, excellent safety profile, and preliminary mechanistic evidence support the urgent need for large-scale randomized controlled trials examining thiamine supplementation to definitively establish efficacy, optimal dosing, and patient selection criteria. Full article

To clarify how nitrogen (N) and water regulate the microbe mediated carbon (C) cycle in farmland, a 3-year experiment was conducted in a wheat–maize rotation at Jiaozhou Station, North China. Twelve treatments combined four drip irrigation regimes (T1: no irrigation; T2: 40 mm irrigation at flowering; T3: 40 mm irrigation at the grain filling stage; T4: both, 40 mm each) and three N levels (N0: 0 kgN·hm⁻²; N1: 92 kgN·hm⁻²; N2: 184 kgN·hm⁻²). In this study, we measured wheat yield and biomass, soil organic carbon and nitrogen content, soil respiration, soil microbial community, and C-metabolic genes. The results showed that wheat yield increased with N, peaking at 8949.81 kg·hm⁻² in the N2T3 treatment, while irrigation had no significant independent effect on yield but interacted with nitrogen fertilization: under identical nitrogen levels (N1, N2), yields in the T1 and T2 treatments were significantly lower than those in the T3/T4 treatments. The soil organic carbon content in N2 was significantly higher; the soil C/N ratio was highest in N2, and T3 resulted in a significantly higher C/N ratio than T1 under the same N level; total soil respiration in N0 was significant lower, and T4 had higher respiration than T2 under the same N level. N addition increased Actinobacteriota, Chloroflexi, Gemmatimonadetes, and Ascomycota, while decreaing Proteobacteria and Acidobacteriota. No reduction in fungal phylum was observed with nitrogen addition. N application significantly upregulated key enzymes in the pentose phosphate pathway (e.g., transketolase K00615, transaldolase K00616), while irrigation increased phosphoserine aminotransferase (K00831) abundance and decreased methylmalonyl-CoA mutase (K01848) abundance. N2T3 maintains high SOC content while achieving maximum yield, promoting soil fertility retention. Compared to T4, N2T3 also enhances water use efficiency. The N2T3 treatment (high N and grain filling stage irrigation) achieved the optimal balance between high wheat yield and SOC sequestration. Full article

Transketolase-like protein 1 (TKTL-1) has been implicated in altered cancer metabolism, yet its structure and molecular function remain poorly understood. In this study, we established a homology model of TKTL-1 using multiple templates and validated it through sequence alignment and structural comparison with the canonical transketolase (TKT). Binding-site identification was performed using CASTp, receptor cavity mapping, and blind docking, all of which consistently pointed to a conserved region involving interactive residues shared between TKT and TKTL-1. Comparative docking revealed the reduced affinity of TKTL-1 for TDP, supporting functional divergence between TKTL-1 and TKT. We further analyzed conserved residues and receptor surfaces, which enabled us to propose predictive scaffolds as potential modulators of TKTL-1. While these scaffolds remain theoretical, they provide a computational framework to guide future pharmacophore modeling, molecular dynamics simulations, and experimental validation. Together, our study highlights the structural features of TKTL-1, establishes its key differences from TKT, and lays the groundwork for future drug discovery efforts targeting cancer metabolism. Full article

Background: Early neurovascular unit (NVU) impairment plays a critical role in the pathogenesis of diabetic retinopathy (DR), often preceding clinically detectable changes. Butyrate, a short-chain fatty acid (SCFA) derived from gut microbiota, has shown promising metabolic and anti-inflammatory effects. Methods: This study investigated the protective potential of oral butyrate supplementation in a mouse model of early type 2 diabetes mellitus (T2DM) induced by a high-fat diet and streptozotocin. Mice (C57BL/6J) received sodium butyrate (5 g/L in drinking water) for 12 weeks. Retinal NVU integrity was assessed using widefield swept-source optical coherence tomography angiography (WF SS-OCTA), alongside evaluations of systemic glucose and lipid metabolism, hepatic steatosis, visual function, and gut microbiota composition via 16S rRNA sequencing. Results: Butyrate supplementation significantly reduced body weight, fasting glucose, serum cholesterol, and hepatic lipid accumulation. Microbiome analysis demonstrated a partial reversal of gut dysbiosis, characterized by increased SCFA-producing taxa (Ruminococcaceae, Oscillibacter, Lachnospiraceae) and decreased pro-inflammatory, lipid-metabolism-related genera (Rikenella, Ileibacterium). KEGG pathway analysis further revealed enrichment in microbial lipid metabolism functions (fabG, ABC.CD.A, and transketolase). Retinal vascular and neurodegenerative alterations—including reduced vessel density and retinal thinning—were markedly attenuated by butyrate, as revealed by WF SS-OCTA. OKN testing indicated partial improvement in visual function, despite unchanged ERG amplitudes. Conclusions: Butyrate supplementation mitigates early NVU damage in the diabetic retina by improving glucose and lipid metabolism and partially restoring gut microbial balance. This study also underscores the utility of WF SS-OCTA as a powerful noninvasive tool for detecting early neurovascular changes in DR. Full article

Salt stress severely impairs photosynthesis and development in tomato seedlings. This study investigated the regulatory role of exogenous melatonin (MT) on photosynthetic performance under salt stress by determining chlorophyll content, chlorophyll a fluorescence parameters, Calvin cycle enzyme activities, and related gene expression. Results showed that salt stress significantly reduced chlorophyll content and impaired photosystem II (PSII) functionality, as evidenced by the increased minimum fluorescence (F_o) and decreased maximum quantum efficiency of PSII (F_v/F_m) and effective PSII quantum yield (Φ_PSII). MT application mitigated these negative effects, as reflected by higher F_v/F_m, increased chlorophyll content, and lower non-photochemical quenching (NPQ). In addition, MT-treated plants exhibited improved PSII electron transport and more efficient use of absorbed light energy, as shown by elevated Φ_PSII and qP values. These changes suggest improved PSII functional stability and reduced excess thermal energy dissipation. Furthermore, MT significantly enhanced both the activity and expression of key enzymes involved in the Calvin cycle, including ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), Rubisco activase (RCA), phosphoglycerate kinase (PGK), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), fructose-1,6-bisphosphatase (FBPase), fructose-bisphosphate aldolase (FBA), transketolase (TK), and sedoheptulose-1,7-bisphosphatase (SBPase), thereby promoting carbon fixation and ribulose-1,5-bisphosphate (RuBP) regeneration under salt stress. Conversely, inhibition of endogenous MT synthesis by p-CPA exacerbated salt stress damage, further confirming MT’s crucial role in salt tolerance. These findings demonstrate that exogenous MT enhances salt tolerance in tomato seedlings by simultaneously improving photosynthetic electron transport efficiency and upregulating the activity and gene expression of key Calvin cycle enzymes, thereby promoting the coordination between light reactions and carbon fixation processes. This study provides valuable insights into the comprehensive regulatory role of MT in maintaining photosynthetic performance under saline conditions. Full article

Sub-optimal light environments in controlled agricultural settings often limit the productivity of plants. While LED supplementary lighting has been widely adopted to mitigate light deficiencies, the spatial arrangement of LED light sources remains a critical but under-explored factor affecting plant physiological responses. In this study, we used the affiliation function method to comprehensively analyze the effects of four spatial LED supplementary lighting configurations—top-down lighting (T1), mid-canopy upward lighting (T2), mid-canopy downward lighting (T3), and bottom-up lighting (T4)—on the growth and photosynthetic performance of tomato plants. Our findings reveal that the T1 treatment significantly increased light absorption in the upper and middle leaves, enhanced photosynthetic efficiency, promoted the CO₂ assimilation rate, and elevated the activities of key Calvin cycle enzymes, including ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), fructose-1,6-bisphosphatase (FBPase), transketolase (TK), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and fructose-1,6-bisphosphate aldolase (FBA). These changes led to improved carbohydrate metabolism and biomass accumulation. Additionally, the T4 treatment markedly enhanced photosynthetic activity in the lower leaves, increasing sugar metabolism-related enzyme activities, such as sucrose synthase (SS), sucrose phosphate synthase (SPS), acid invertase (AI), and neutral invertase (NI). Consequently, compared with the CK treatment, the T4 treatment significantly increased the accumulation of glucose, fructose, and sucrose, with increases of 47.36%, 27.61%, and 87.21%, respectively. Furthermore, LED supplementation regulated endogenous hormone levels, thereby promoting overall plant growth. This study highlights the importance of the spatial arrangement of LEDs in optimizing light distribution and enhancing plant productivity, providing valuable theoretical and practical insights for improving agricultural practices in controlled environments. Full article

Phenolic diterpene carnosic acid (CA) is widely used in the food, nutritional health, and cosmetic industries due to its antioxidative and antimicrobial properties. This work aimed to overproduce CA in Saccharomyces cerevisiae from sugarcane syrup in fed-batch 2 L bioreactor fermentation. A geranylgeranyl diphosphate (GGPP)-producing strain modified with genes encoding the enzymes copalyl diphosphate synthase (Pv.CPS), miltiradiene synthase (Ro.KSL2), hydroxy ferruginol synthase (Ro.HFS), CA synthase (Ro.CYP76AK8), CYP reductase (At.ATR1), and transketolase (TKL1) was used. Lowering the feed rate from 12–26 g/L/h to 7–8 g/L/h, and the use of a dynamic dissolved oxygen (DO) trigger (min. 10%, max. 40%, threshold 70%) instead of a DO trigger of 30%, enhanced CA production by 27%. As a result, the highest CA titer ever reported to date, 191.4 mg/L, was obtained in 4-day fermentation. This study shows the feasibility of engineered yeast to produce CA from the sustainable feedstock sugarcane syrup. Full article

Worldwide, lung cancer is the most common cause of cancer-related death, which is made worse by the development of drug resistance during treatment. It is urgent to develop new therapeutic methods and small molecule drugs for tumor resistance. Chaetocin, extracted from Chaetomium minutum, is a natural compound with good antitumor activity. However, there are few studies on its tumor resistance. In this paper, firstly, chaetotocin significantly inhibited the viability and migration of cisplatin-resistant non-small cell lung cancer (NSCLC) cells and inhibited the xenograft growth of nude mice. Chaetocin at 4 mg/kg significantly inhibited A549/DDP xenograft growth with an inhibition rate of 70.43%. Subsequently, the underlying mechanism behind the actions of chaetocin was explored. It was discovered that chaetocin can inhibit transketolase (TKT), thereby inhibiting the growth of NSCLC cells and inducing cell death. Compared with cisplatin-sensitive cells, a lower concentration of chaetocin can inhibit cisplatin-resistance cell viability and migration. Mechanistically, TKT was identified as a potential target for chaetocin. The KD value of the interaction between chaetocin and TKT was 63.2 μM. An amount of 0.2 μM chaetocin may suppress the enzyme activity and expression level of TKT. We found the TKT expression is higher in cisplatin-resistant cells, which further explains why these cells were more vulnerable to chaetocin in terms of cell phenotype. Additionally, the muti-omics analysis and RNA interference suggested that chaetocin can inhibit the PI3K/Akt signaling pathway through TKT. In conclusion, chaetocin could directly bind to TKT, inhibiting its enzyme activity and expression, which interfered with intracellular metabolism and oxidation-reduction balance, and then regulated the PI3K/Akt signaling pathway to inhibit the growth of NSCLC and induce apoptosis. Full article

Fluorescent protein-tagged bacterial strains are widely used tools for studying host-pathogen interactions and microbial dynamics. In this study, we developed and characterized Vibrio harveyi strains genetically modified to express green fluorescent protein (GFP) and red fluorescent protein (RFP). These strains were constructed using triparental mating and evaluated for phenotypic, genomic, and virulence attributes. Genomic analyses revealed strain-specific variations, including mutations in key regulatory and metabolic genes, such as luxO and transketolase. While plasmid acquisition imposed metabolic costs, resulting in altered growth and antibiotic sensitivities in certain transconjugants, others demonstrated robust phenotypic stability. Virulence assays using gilthead seabream larvae revealed that most tagged strains retained moderate pathogenicity, with visualization of co-infections highlighting the potential for studying strain-specific interactions. Furthermore, fluorescent microscopy confirmed the successful colonization and localization of tagged bacteria within host tissues. These findings underscore the utility of GFP- and RFP-tagged Vibrio harveyi as versatile tools for infection dynamics, offering a foundation for future research on strain interactions and pathogen-host relationships. Full article

The pentose phosphate pathway (PPP) is essential for human health and provides, amongst others, the reduction power to cope with oxidative stress. In contrast to the model baker’s yeast, the PPP also contributes to a large extent to glucose metabolism in the milk yeast Kluyveromyces lactis. Yet, the physiological consequences of mutations in genes encoding PPP enzymes in K. lactis have been addressed for only a few. We here embarked on a systematic study of such mutants, deleting ZWF1, SOL4, GND1, RKI1, RPE1, TKL1, TAL1, and SHB17. Interestingly, GND1, RKI1, and TKL1 were found to be essential under standard growth conditions. Epistasis analyses revealed that a lack of Zwf1 rescued the lethality of the gnd1 deletion, indicating that it is caused by the accumulation of 6-phosphogluconate. Moreover, the slow growth of a tal1 null mutant, which lacks fructose-1,6-bisphosphate aldolase, was aggravated by deleting the SHB17 gene encoding sedoheptulose-1,7-bisphosphatase. A mitotically stable tetOFF system was established for conditional expression of TAL1 and TKL1, encoding transaldolase and transketolase in the non-oxidative part of the PPP, and employed in a global proteome analysis upon depletion of the enzymes. Results indicate that fatty acid degradation is upregulated, providing an alternative energy source. In addition, tal1 and tkl1 null mutants were complemented by heterologous expression of the respective genes from baker’s yeast and humans. These data demonstrate the importance of the PPP for basic sugar metabolism and oxidative stress response in K. lactis and the potential of this yeast as a model for the study of PPP enzymes from heterologous sources, including human patients. Full article