Mitochondrial transport and metabolism of the vitamin B-derived cofactors thiamine pyrophosphate, coenzyme A, FAD and NAD+ , and related diseases: A review

Adjustments in energy metabolism of brown adipose tissue in heat-acclimated Kunming mice

The thermogenic capacity of brown adipose tissue (BAT) in rodents decreases with prolonged heat exposure. However, the underlying mechanisms are not well understood. In this study, Kunming mice were acclimated at 23 ± 1 °C and 33 ± 1 °C for four weeks each to examine the body heat balance and BAT alterations. Results showed that heat-acclimated Kunming mice exhibited reduced body mass and elevated body temperature. Additionally, they displayed lower resting metabolic rates, diminished non-shivering thermogenesis, and reduced BAT thermogenic function. Metabolically, there was a significant reduction in several key metabolites involved in energy metabolism in BAT, including thiamine pyrophosphate, citric acid, cis-Aconitate, isocitric acid, oxoglutaric acid, succinate, fumarate, L-Malic acid, oxaloacetate, flavin mononucleotide, nicotinamide adenine dinucleotide, and adenosine 5'-triphosphate. These findings suggest that BAT adapts to heat acclimation by regulating pathways related to pyruvate oxidation, tricarboxylic acid cycle, and oxidative phosphorylation, which may help maintain thermal homeostasis in Kunming mice.

SLC25A19 is required for NADH homeostasis and mitochondrial respiration

Mitochondrial transporters facilitate the translocation of metabolites between the cytoplasm and mitochondria and are critical for mitochondrial functional integrity. Although many mitochondrial transporters are associated with metabolic diseases, how they regulate mitochondrial function and their metabolic contributions at the cellular level are largely unknown. Here, we show that mitochondrial thiamine pyrophosphate (TPP) transporter SLC25A19 is required for mitochondrial respiration. SLC25A19 deficiency leads to reduced cell viability, increased integrated stress response (ISR), enhanced glycolysis and elevated cell sensitivity to 2-deoxyglucose (2-DG) treatment. Through a series of biochemical assays, we found that the depletion of mitochondrial NADH is the primary cause of the impaired mitochondrial respiration in SLC25A19 deficient cells. We also showed involvement of SLC25A19 in regulating the enzymatic activities of complexes I and III, the tricarboxylic acid (TCA) cycle, malate-aspartate shuttle and amino acid metabolism. Consistently, addition of idebenone, an analog of coenzyme Q10, restores mitochondrial respiration and cell viability in SLC25A19 deficient cells. Together, our findings provide new insight into the functions of SLC25A19 in mitochondrial and cellular physiology, and suggest that restoring mitochondrial respiration could be a novel strategy for treating SLC25A19-associated disorders.

Unveiling the toxicological effects and risks of prometryn on red swamp crayfish (Procambarus clarkii): Health assessments, ecological, and molecular insights

Prometryn is commonly used in agricultural and non-agricultural settings. However, possible harm to aquatic organisms remains a persistent concern. Prometryn was also the only one of the 26 triazine herbicides detected in this study. Numerous studies have assessed the harmful effects of prometryn in teleost fish and shrimp. There is a lack of information regarding the ecological and human health risks, as well as the toxic mechanisms affecting crayfish. In this study, human health risk assessment (THQ) and ecological risk assessment (RQ) were conducted on P. clarkii in the rice-crayfish co-culture (IRCC) farming model. The 96 h of exposure to 0.286 mg/L and 1.43 mg/L prometryn was conducted to investigate the potential effects and molecular mechanisms of hepatopancreatic resistance to prometryn in P. clarkii. The original sample analysis revealed that the THQ calculated from the prometryn levels in the muscle and hepatopancreas was below 0.1, suggesting no threat to human health. However, the calculated RQ values were >0.1, indicating a risk to P. clarkii. Histological analysis and biochemical index detection of the experimental samples revealed that the hepatopancreatic injury and oxidative damage in P. clarkii were caused by prometryn. Moreover, transcriptome analysis identified 2512 differentially expressed genes (DEGs) after 96 h of prometryn exposure. Prometryn exposure caused significant changes in metabolic pathways, including oxoacid metabolic processes and cytochrome P450-associated drug metabolism. Further hub gene analysis via PPI indicated that exposure to prometryn may inhibit lipid synthesis, storage, and amino acid transport and affect glucose metabolic pathways and hormone synthesis. Additionally, we hypothesized that prometryn-triggered cell death could be linked to the PI3K-Akt signaling cascade. This study's findings have significant meaning for the efficient and logical application of herbicides in IRCC, ultimately aiding in advancing a highly productive agricultural system.

Antibacterial mechanism of metabolites of Lactobacillus plantarum against Pseudomonas lundensis and their application in dry-aged beef preservation

In this study, the antibacterial mechanism of metabolites of Lactobacillus plantarum SCB2505 (MLp SCB2505) against Pseudomonas lundensis (P. lundensis) SCB2605 was investigated, along with evaluation of their preservative effects on dry-aged beef. The results demonstrated the effective inhibition of MLp SCB2505 on the growth and biofilm synthesis of P. lundensis. The treatment with MLp SCB2505 led to the compromised membrane integrity, as evidenced by reduced intracellular ATP content, increased extracellular AKPase, K+ and protein content, as well as disrupted cell morphology. Further metabolomics analysis revealed that MLp SCB2505 interfered amino acid metabolism, nucleotide metabolism, cofactor and vitamin metabolism, lipid metabolism and respiratory chain in P. lundensis, ultimately leading to the interrupted life activities and even death of the bacteria. Besides, MLp SCB2505 could effectively inhibit the growth of Pseudomonas in dry-aged beef and delay spoilage. These findings propose the potential application of MLp SCB2505 as an antibacterial agent in meat products.

Decreasing Intracellular Entropy by Increasing Mitochondrial Efficiency and Reducing ROS Formation-The Effect on the Ageing Process and Age-Related Damage

A hypothesis is presented to explain how the ageing process might be influenced by optimizing mitochondrial efficiency to reduce intracellular entropy. Research-based quantifications of entropy are scarce. Non-equilibrium metabolic reactions and compartmentalization were found to contribute most to lowering entropy in the cells. Like the cells, mitochondria are thermodynamically open systems exchanging matter and energy with their surroundings-the rest of the cell. Based on the calculations from cancer cells, glycolysis was reported to produce less entropy than mitochondrial oxidative phosphorylation. However, these estimations depended on the CO2 concentration so that at slightly increased CO2, it was oxidative phosphorylation that produced less entropy. Also, the thermodynamic efficiency of mitochondrial respiratory complexes varies depending on the respiratory state and oxidant/antioxidant balance. Therefore, in spite of long-standing theoretical and practical efforts, more measurements, also in isolated mitochondria, with intact and suboptimal respiration, are needed to resolve the issue. Entropy increases in ageing while mitochondrial efficiency of energy conversion, quality control, and turnover mechanisms deteriorate. Optimally functioning mitochondria are necessary to meet energy demands for cellular defence and repair processes to attenuate ageing. The intuitive approach of simply supplying more metabolic fuels (more nutrients) often has the opposite effect, namely a decrease in energy production in the case of nutrient overload. Excessive nutrient intake and obesity accelerate ageing, while calorie restriction without malnutrition can prolong life. Balanced nutrient intake adapted to needs/activity-based high ATP requirement increases mitochondrial respiratory efficiency and leads to multiple alterations in gene expression and metabolic adaptations. Therefore, rather than overfeeding, it is necessary to fine-tune energy production by optimizing mitochondrial function and reducing oxidative stress; the evidence is discussed in this paper.

Varying association of nutrient intakes with quality of life in patients receiving different modes of dialysis

Background

Nutrients are crucial for dialysis patients, especially elderly patients. Nutrition-related complications in dialysis patients are often closely related to cardiovascular aging. However, we know little about the effect of different nutrients on the commonly used outcome predictor, health-related quality of life (HRQOL). Therefore, this study investigated the associations between different nutrients and HRQOL among dialysis patients.

Methods

A cross-sectional study was conducted on 123 dialysis adults at multiple dialysis centers. The Short Form-36 Health Survey (SF-36) assesses HRQOL. Modified quantitative subjective global assessment (MQSGA) evaluates nutritional status. A 3-day dietary record evaluated nutrient intakes.

Results

Among the 123 participants, 79 received hemodialysis (HD), and 44 were on peritoneal dialysis (PD). Patients with PD had a higher SF-36 score than HD (525 ± 136 vs. 375 ± 179, P < 0.001). A negative association between nutrition status and HRQOL was observed in HD (regression coefficient β = -17.4, P < 0.001) but not in PD (β = -12.3, P = 0.07). For HD patients, the nutrition status was negatively correlated with intakes of carbohydrates, fiber, selenium, copper, and Manganese (β = -0.02, P = 0.032; β = -0.3, P = 0.031; β = -0.1, P = 0.006; β = -2.3, P = 0.025; β = -1.3, P = 0.003, respectively). Their HRQOL was positively associated with calories, fat, niacin, and vitamin E (β = 2.19, P = 0.035; β = 2.4, P = 0.043; β = 8.5, P = 0.044; β = 6.9, P = 0.017, respectively). Conversely, for patients with PD, only vitamin B2 was found to be adversely correlated with their nutritional status (β = -5.2, P = 0.037), and increased intakes of vitamin A, vitamin C and fiber (β = 0.1, P = 0.031; β = 0.8, P = 0.028; β = 15.8, P = 0.045, respectively) were associated with a better HRQOL.

Conclusions

The nutritional intake of PD patients and HD patients affects their quality of life differently. Macronutrients significantly impact HRQOL in HD patients, while vitamins have a more substantial impact on PD patients.

Sodium Metabisulfite Inhibits Acanthamoeba Trophozoite Growth through Thiamine Depletion

Acanthamoeba keratitis (AK) is a severe infection of the cornea. Prevention and treatment are difficult due to the inefficacy of currently available compounds. The impact of many commonly used compounds for routine examinations of Acanthamoeba is unexplored but might offer insight useful in combatting AK. In this study, we demonstrate that sodium metabisulfite, a common preservation constituent of eye care solutions, was found to be active against Acanthamoeba trophozoites at concentrations lower than that commonly found in eye drops (IC50 0.03 mg/mL). We demonstrate that sodium metabisulfite depletes thiamine from growth medium and that Acanthamoeba is a thiamine auxotroph, requiring thiamine salvage for growth. The inhibitory effects of sodium metabisulfite can be overcome by thiamine supplementation. These results are consistent with the lack of key enzymes for thiamine biosynthesis in the genome of Acanthamoeba, an area which might prove exploitable using new or existing compounds. Indeed, this study highlights sodium metabisulfite as a useful inhibitor of Acanthamoeba castellanii trophozoites in vitro and that it acts, at least in part, by limiting available thiamine.

Hypoxia leads to gill endoplasmic reticulum stress and disruption of mitochondrial homeostasis in grass carp (Ctenopharyngodon idella): Mitigation effect of thiamine

Hypoxia in water environment is one of the important problems faced by intensive aquaculture. Under hypoxia stress, the effects of dietary thiamine were investigated on grass carp gill tissue damage and their mechanisms. Six thiamine diets with different thiamine levels (0.22, 0.43, 0.73, 1.03, 1.33 and 1.63 mg/kg) were fed grass carp (Ctenopharyngodon idella) for 63 days. Then, 96-hour hypoxia stress test was conducted. This study described that thiamine enhanced the growth performance of adult grass carp and ameliorated nutritional status of thiamine (pyruvic acid, glucose, lactic acid and transketolase). Additionally, thiamine alleviated the deterioration of blood parameters [glutamic oxalacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), glucose, cortisol, lactic dehydrogenase (LDH), erythrocyte fragility, and red blood cell count (RBC count)] caused by hypoxia stress, and reduced reactive oxygen species (ROS) content and oxidative damage to the gills. In addition, thiamine alleviated endoplasmic reticulum stress in the gills, which may be related to its inhibition of RNA-dependent protein kinase-like ER kinase (PERK)/eukaryotic translation initiation factor-2α (eIF2α)/activating transcription factor4 (ATF4), inositol-requiring enzyme 1 (IRE1)/X-Box binding protein 1 (XBP1) and activating transcription factor 6 (ATF6) pathways. Furthermore, thiamine maintaining mitochondrial dynamics balance was probably related to promoting mitochondrial fusion and inhibiting mitochondrial fission, and inhibiting mitophagy may involve PTEN induced putative kinase 1 (PINK1)/Parkin-dependent pathway and hypoxia-inducible factor (HIF)-Bcl-2 adenovirus E1B 19 kDa interacting protein 3 (BNIP3) pathway. In summary, thiamine alleviated hypoxia stress in fish gills, which may be related to reducing endoplasmic reticulum stress, regulating mitochondrial dynamics balance and reducing mitophagy. The thiamine requirement for optimum growth [percent weight gain (PWG)] of adult grass carp was estimated to be 0.81 mg/kg diet. Based on the index of anti-hypoxia stress (ROS content in gill), the thiamine requirement for adult grass carp was estimated to be 1.32 mg/kg diet.

Enhancing erythromycin production in Saccharopolyspora erythraea through rational engineering and fermentation refinement: A Design-Build-Test-Learn approach

Industrial production of bioactive compounds from actinobacteria, such as erythromycin and its derivatives, faces challenges in achieving optimal yields. To this end, the Design-Build-Test-Learn (DBTL) framework, a systematic metabolic engineering approach, was employed to enhance erythromycin production in Saccharopolyspora erythraea (S. erythraea) E3 strain. A genetically modified strain, S. erythraea E3-CymRP21-dcas9-sucC (S. erythraea CS), was developed by suppressing the sucC gene using an inducible promoter and dcas9 protein. The strain exhibited improved erythromycin synthesis, attributed to enhanced precursor synthesis and increased NADPH availability. Transcriptomic and metabolomic analyses revealed altered central carbon metabolism, amino acid metabolism, energy metabolism, and co-factor/vitamin metabolism in CS. Augmented amino acid metabolism led to nitrogen depletion, potentially causing cellular autolysis during later fermentation stages. By refining the fermentation process through ammonium sulfate supplementation, erythromycin yield reached 1125.66 mg L-1, a 43.5% increase. The results demonstrate the power of the DBTL methodology in optimizing erythromycin production, shedding light on its potential for revolutionizing antibiotic manufacturing in response to the global challenge of antibiotic resistance.

Vitamin Nutritional Status in Patients with Pancreatic Cancer: A Narrative Review

Due to the high mortality rate in Western countries, pancreatic cancer is considered one of the big killers, leaving patients and their families with little hope upon diagnosis. Although surgical and drug therapies are critical for cancer patients to improve life expectancy and alleviation of suffering, nutrition plays a key role in improving cancer treatment outcomes. This narrative review, conducted as part of the activities of the Italian Society of Human Nutrition (SINU) working group in oncology, focuses on the prevalence of vitamin malnutrition among pancreatic cancer patients. The results of the literature search show that pancreatic cancer patients are at a heightened risk of water-soluble vitamin deficiencies, particularly of vitamins B1, B3, and B6. Additionally, they also face an increased risk of deficiency of fat-soluble vitamins. Among these vitamins, the potential role of vitamin D in pancreatic cancer has garnered the most attention, with its plasma levels being identified as a significant factor in patient survival. Investigating vitamin nutritional status could provide valuable insights for incorporating nutritional approaches into the prevention and treatment of pancreatic cancer, thereby reducing the exacerbation of symptoms associated with the diagnosis.

In Vitro and In Silico Studies on Cytotoxic Properties of Oxythiamine and 2'-Methylthiamine

It is important to search for cytostatic compounds in order to fight cancer. One of them could be 2'-methylthiamine, which is a thiamine antimetabolite with an additional methyl group at the C-2 carbon of thiazole. So far, the cytostatic potential of 2'-methylthiamine has not been studied. We have come forward with a simplified method of synthesis using commercially available substrates and presented a comparison of its effects, as boosted by oxythiamine, on normal skin fibroblasts and HeLa cancer cells, having adopted in vitro culture techniques. Oxythiamine has been found to inhibit the growth and metabolism of cancer cells significantly better than 2'-methylthiamine (GI50 36 and 107 µM, respectively), while 2'-methylthiamine is more selective for cancer cells than oxythiamine (SI = 180 and 153, respectively). Docking analyses have revealed that 2'-methylthiamine (ΔG -8.2 kcal/mol) demonstrates a better affinity with thiamine pyrophosphokinase than thiamine (ΔG -7.5 kcal/mol ) and oxythiamine (ΔG -7.0 kcal/mol), which includes 2'-methylthiamine as a potential cytostatic. Our results suggest that the limited effect of 2'-methylthiamine on HeLa arises from the related arduous transport as compared to oxythiamine. Given that 2'-methylthiamine may possibly inhibit thiamine pyrophosphokinase, it could once again be considered a potential cytostatic. Thus, research should be carried out in order to find the best way to improve the transport of 2'-methylthiamine into cells, which may trigger its cytostatic properties.

Enhanced branched-chain amino acid metabolism improves age-related reproduction in C. elegans

Reproductive ageing is one of the earliest human ageing phenotypes, and mitochondrial dysfunction has been linked to oocyte quality decline; however, it is not known which mitochondrial metabolic processes are critical for oocyte quality maintenance with age. To understand how mitochondrial processes contribute to Caenorhabditis elegans oocyte quality, we characterized the mitochondrial proteomes of young and aged wild-type and long-reproductive daf-2 mutants. Here we show that the mitochondrial proteomic profiles of young wild-type and daf-2 worms are similar and share upregulation of branched-chain amino acid (BCAA) metabolism pathway enzymes. Reduction of the BCAA catabolism enzyme BCAT-1 shortens reproduction, elevates mitochondrial reactive oxygen species levels, and shifts mitochondrial localization. Moreover, bcat-1 knockdown decreases oocyte quality in daf-2 worms and reduces reproductive capability, indicating the role of this pathway in the maintenance of oocyte quality with age. Notably, oocyte quality deterioration can be delayed, and reproduction can be extended in wild-type animals both by bcat-1 overexpression and by supplementing with vitamin B1, a cofactor needed for BCAA metabolism.

Integrative analysis of the transcriptome and metabolome reveals Bacillus atrophaeus WZYH01-mediated salt stress mechanism in maize (Zea mays L.)

Maize is an important food crop that is affected by salt stress during growth, which can hinder plant growth and result in a significant decrease in yield. The application of plant growth-promoting rhizobacteria can improve this situation to a certain extent. However, the gene network of rhizosphere-promoting bacteria regulating the response of maize to salt stress remains elusive. Here, we used metabolomics and transcriptomics techniques to elucidate potential gene networks and salt-response pathways in maize. Phenotypic analysis showed that the Bacillus atrophaeus treatment improved the plant height, leaf area, biomass, ion, nutrient and stomatal indicators of maize. Metabolomic analysis identified that differentially expressed metabolites (DEMs) were primarily concentrated in the arginine, proline and phytohormone signaling metabolic pathways. 4-Hydroxyphenylacetylglutamic acid, L-histidinol, oxoglutaric acid, L-glutamic acid, L-arginine, and L-tyrosine were significantly increased in the Bacillus atrophaeus treatment. Weighted gene coexpression network analysis (WGCNA) identified several hub genes associated with salt response: Zm00001eb155540 and Zm00001eb088790 (ABC transporter family), Zm00001eb419060 (extra-large GTP-binding protein family), Zm00001eb317200 (calcium-transporting ATPase), Zm00001eb384800 (aquaporin NIP1-4) and Zm00001eb339170 (cytochrome P450). Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that genes related to plant hormone signal transduction and the MAPK signaling pathway were involved in the response to the effect of Bacillus atrophaeus under salt stress. In the plant hormone signal transduction pathway, 3 differentially expressed genes (DEGs) encoding EIN3/EILs protein, 3 DEGs encoding GH3, 1 DEG encoding PYR/PYL and 6 DEGs encoding PP2C were all upregulated in Bacillus atrophaeus treatment. In the MAPK signaling pathway, 2 DEGs encoding CAT1 and 2 DEGs encoding WRKY22/WRKY29 were significantly upregulated, and the expression of DEGs encoding RbohD was downregulated by the application of Bacillus atrophaeus. In conclusion, the application of Bacillus atrophaeus under salt stress regulated key physiological and molecular processes in plants, which could stimulate the expression of genes related to ion transport and nutrients in maize, alleviate salt stress and promote maize growth to some extent, deepening our understanding of the application of Bacillus atrophaeus under salt stress to improve the salt-response gene network of maize growth.

Brain transcriptomic, metabolic and mitohormesis properties associated with N-propargylglycine treatment: A prevention strategy against neurodegeneration

INTRODUCTION

There is an urgent need for new or repurposed therapeutics that protect against or significantly delay the clinical progression of neurodegenerative diseases, such as Huntington's disease (HD), Parkinson's disease and Alzheimer's disease. In particular, preclinical studies are needed for well tolerated and brain-penetrating small molecules capable of mitigating the proteotoxic mitochondrial processes that are hallmarks of these diseases. We identified a unique suicide inhibitor of mitochondrial proline dehydrogenase (Prodh), N-propargylglycine (N-PPG), which has anticancer and brain-enhancing mitohormesis properties, and we hypothesize that induction of mitohormesis by N-PPG protects against neurodegenerative diseases. We carried out a series of mouse studies designed to: i) compare brain and metabolic responses while on oral N-PPG treatment (50 mg/kg, 9-14 days) of B6CBA wildtype (WT) and short-lived transgenic R6/2 (HD) mice; and ii) evaluate potential brain and systemwide stress rebound responses in WT mice 2 months after cessation of extended mitohormesis induction by well-tolerated higher doses of N-PPG (100-200 mg/kg x 60 days). WT and HD mice showed comparable global evidence of N-PPG induced brain mitohormesis characterized by Prodh protein decay and increased mitochondrial expression of chaperone and Yme1l1 protease proteins. Interestingly, transcriptional analysis (RNAseq) showed partial normalization of HD whole brain transcriptomes toward those of WT mice. Comprehensive metabolomic profiles performed on control and N-PPG treated blood, brain, and kidney samples revealed expected N-PPG-induced tissue increases in proline levels in both WT and HD mice, accompanied by surprising parallel increases in hydroxyproline and sarcosine. Two months after cessation of the higher dose N-PPG stress treatments, WT mouse brains showed robust rebound increases in Prodh protein levels and mitochondrial transcriptome responses, as well as altered profiles of blood amino acid-related metabolites. Our HD and WT mouse preclinical findings point to the brain penetrating and mitohormesis-inducing potential of the drug candidate, N-PPG, and provide new rationale and application insights supporting its further preclinical testing in various models of neurodegenerative diseases characterized by loss of mitochondrial proteostasis.

Targeting mitochondria with antioxidant nutrients for the prevention and treatment of postweaning diarrhea in piglets

Post-weaning diarrhea (PWD) in piglets poses a significant challenge and presents a grave threat to the global swine industry, resulting in considerable financial losses and compromising the welfare of animals. PWD is commonly associated with gut homeostatic imbalance, including oxidative stress, excessive inflammation, and microbiota dysbiosis. Antibiotic use has historically been a common initiative to combat PWD, but concerns about the development of antibiotic resistance have led to increased interest in alternative strategies. Mitochondria are key players in maintaining cellular homeostasis, and their dysfunction is intricately linked to the onset and progression of PWD. Accumulating evidence suggests that targeting mitochondrial function using antioxidant nutrients, such as vitamins, minerals and polyphenolic compounds, may represent a promising approach for preventing and treating PWD. Moreover, nutrients based on antioxidant strategies have been shown to improve mitochondrial function, restore intestinal redox balance, and reduce oxidative damage, which is a key driver of PWD. The present review begins with an overview of the potential interplay between mitochondria and gut homeostasis in the pathogenesis of PWD in piglets. Subsequently, alternative strategies to prevent and treat PWD using antioxidant nutrients to target mitochondria are described and discussed. Ultimately, we delve into potential limitations and suggest future research directions in this field for further advancement. Overall, targeting mitochondria using antioxidant nutrients may be a promising approach to combat PWD and provides a potential nutrition intervention strategy for regulating gut homeostasis of weaned piglets.

An exploration of mechanism of high quality and yield of Gastrodia elata Bl. f. glauca by the isolation, identification, and evaluation of Mycena

Gastrodia elata Bl. f. glauca is an important traditional Chinese medicinal plant. The yield and quality of Gastrodia elata Bl. have significantly decreased due to multigenerational asexual reproduction. Therefore, it is necessary to have sexual reproduction of Gastrodia elata Bl. to supplement the market supply. Seeds of G. elata Bl. have no endosperm, and their sexual reproduction depends on the nutrients provided by the embryo cells infected by Mycena fungi to complete seed germination. However, Mycena fungi are small and have many species, and not all Mycena fungi can promote the germination of G. elata Bl. seeds. Therefore, it is of great significance to isolate and identify suitable germination fungi and explore the mechanism for improving the production performance and yield, and quality of G. elata Bl. Six closely related Mycena isolates, JFGL-01, JFGL-02, JFGL-03, JFGL-04, JFGL-05, and JFGL-06, were isolated from the leaves and protocorms of G. elata Bl. f. glauca and were identified as Mycena purpureofusca. The mycelial state and number of germinating protocorms were used as indicators to preferentially select Mycena fungi, and it was concluded that JFGL-06 had the best mycelial state and ability to germinate G. elata Bl. seeds. Finally, a mechanism to increase the yield of G. elata Bl. was explored by comparing the changes in nutrient elements and microbial diversity in the soil around G. elata Bl. with different strains. JFGL-06 proved to be an excellent Mycena fungal strain suitable for G. elata Bl. f. glauca. Compared with the commercial strain, JFGL-06 significantly increased the C, N, Na, Mg, S, Cl, K, Ca, and Fe contents of the soil surrounding the protocorms of G. elata Bl. f. glauca. JFGL-06 improved the composition, diversity, and metabolic function of the surrounding soil microbial community of G. elata Bl. f. glauca protocorms at the phylum, class, and genus levels, significantly increased the relative abundance of bacteria such as Acidobacteria and fungi such as Trichoderma among the dominant groups, and increased the abundance of functional genes in metabolic pathways such as nucleotide metabolism and energy metabolism. There was a significant reduction in the relative abundance of bacteria, such as Actinomycetes, and fungi, such as Fusarium, in the dominant flora, and a reduced abundance of functional genes, such as amino acid metabolism and xenobiotic biodegradation and metabolism. This is the main reason why the JFGL-06 strain promoted high-quality and high-yield G. elata Bl. f. glauca in Changbai Mountain.

NUDT6 and NUDT9, two mitochondrial members of the NUDIX family, have distinct hydrolysis activities

The 22 members of the NUDIX (NUcleoside DIphosphate linked to another moiety, X) hydrolase superfamily can hydrolyze a variety of phosphorylated molecules including (d)NTPs and their oxidized forms, nucleotide sugars, capped mRNAs and dinucleotide coenzymes such as NADH and FADH. Beside this broad range of enzymatic substrates, the NUDIX proteins can also be found in different cellular compartments, mainly in the nucleus and in the cytosol, but also in the peroxisome and in the mitochondria. Here we studied two members of the family, NUDT6 and NUDT9. We showed that NUDT6 is expressed in human cells and localizes exclusively to mitochondria and we confirmed that NUDT9 has a mitochondrial localization. To elucidate their potential role within this organelle, we investigated the functional consequences at the mitochondrial level of NUDT6- and NUDT9-deficiency and found that the depletion of either of the two proteins results in an increased activity of the respiratory chain and an alteration of the mitochondrial respiratory chain complexes expression. We demonstrated that NUDT6 and NUDT9 have distinct substrate specificity in vitro, which is dependent on the cofactor used. They can both hydrolyze a large range of low molecular weight compounds such as NAD⁺(H), FAD and ADPR, but NUDT6 is mainly active towards NADH, while NUDT9 displays a higher activity towards ADPR.

Generation of a Yeast Cell Model Potentially Useful to Identify the Mammalian Mitochondrial N-Acetylglutamate Transporter

The human mitochondrial carrier family (MCF) consists of 53 members. Approximately one-fifth of them are still orphans of a function. Most mitochondrial transporters have been functionally characterized by reconstituting the bacterially expressed protein into liposomes and transport assays with radiolabeled compounds. The efficacy of this experimental approach is constrained to the commercial availability of the radiolabeled substrate to be used in the transport assays. A striking example is that of N-acetylglutamate (NAG), an essential regulator of the carbamoyl synthetase I activity and the entire urea cycle. Mammals cannot modulate mitochondrial NAG synthesis but can regulate the levels of NAG in the matrix by exporting it to the cytosol, where it is degraded. The mitochondrial NAG transporter is still unknown. Here, we report the generation of a yeast cell model suitable for identifying the putative mammalian mitochondrial NAG transporter. In yeast, the arginine biosynthesis starts in the mitochondria from NAG which is converted to ornithine that, once transported into cytosol, is metabolized to arginine. The deletion of ARG8 makes yeast cells unable to grow in the absence of arginine since they cannot synthetize ornithine but can still produce NAG. To make yeast cells dependent on a mitochondrial NAG exporter, we moved most of the yeast mitochondrial biosynthetic pathway to the cytosol by expressing four E. coli enzymes, argB-E, able to convert cytosolic NAG to ornithine. Although argB-E rescued the arginine auxotrophy of arg8∆ strain very poorly, the expression of the bacterial NAG synthase (argA), which would mimic the function of a putative NAG transporter increasing the cytosolic levels of NAG, fully rescued the growth defect of arg8∆ strain in the absence of arginine, demonstrating the potential suitability of the model generated.

Stability and Requirement for Thiamin in a Cell Culture Feed Used to Produce New Biological Entities

Thiamin is susceptible to heat and oxidation, which is a concern for the development of concentrated and room temperature stable feeds used to produce recombinant proteins. Hence, it is critical to understand the reactivity and necessity of the vitamin in liquid feeds to be able to either develop mitigation strategies to stabilize the vitamin or to remove thiamin from formulations if it is unnecessary. LC-MS/MS was used to investigate thiamin stability in different liquid feed formulations and to identify thiamin degradation products. Results indicate oxidation of thiamin and interaction with amino acids, keto acids, and sulfur containing components. Thiamin necessity in feed was assessed during a fed batch experiment, focusing on cell performance and critical quality attributes of the produced recombinant proteins. The impact of thiamin depletion in the feed on the intra- and extracellular metabolome was investigated using untargeted LC-MS/MS. Results indicate that thiamin can be removed from the feed without affecting the performance or the intra- and extracellular metabolome of the tested cell lines. Overall, profound insights on thiamin reactivity and necessity are presented in this study, suggesting the removal of the dispensable and instable vitamin as a simple means for the development of next generation feeds used to produce therapeutic biological entities.

Role of Mitochondrial Transporters on Metabolic Rewiring of Pancreatic Adenocarcinoma: A Comprehensive Review

Pancreatic cancer is among the deadliest cancers worldwide and commonly presents as pancreatic ductal adenocarcinoma (PDAC). Metabolic reprogramming is a hallmark of PDAC. Glucose and glutamine metabolism are extensively rewired in order to fulfil both energetic and synthetic demands of this aggressive tumour and maintain favorable redox homeostasis. The mitochondrial pyruvate carrier (MPC), the glutamine carrier (SLC1A5_Var), the glutamate carrier (GC), the aspartate/glutamate carrier (AGC), and the uncoupling protein 2 (UCP2) have all been shown to influence PDAC cell growth and progression. The expression of MPC is downregulated in PDAC and its overexpression reduces cell growth rate, whereas the other four transporters are usually overexpressed and the loss of one or more of them renders PDAC cells unable to grow and proliferate by altering the levels of crucial metabolites such as aspartate. The aim of this review is to comprehensively evaluate the current experimental evidence about the function of these carriers in PDAC metabolic rewiring. Dissecting the precise role of these transporters in the context of the tumour microenvironment is necessary for targeted drug development.

Thiamine deficiency in pregnancy and lactation: implications and present perspectives

During pregnancy, many physiologic changes occur in order to accommodate fetal growth. These changes require an increase in many of the nutritional needs to prevent long-term consequences for both mother and the offspring. One of the main vitamins that are needed throughout the pregnancy is thiamine (vitamin B1) which is a water-soluble vitamin that plays an important role in many metabolic and physiologic processes in the human body. Thiamine deficiency during pregnancy can cause can have many cardiac, neurologic, and psychological effects on the mother. It can also dispose the fetus to gastrointestinal, pulmonological, cardiac, and neurologic conditions. This paper reviews the recently published literature about thiamine and its physiologic roles, thiamine deficiency in pregnancy, its prevalence, its impact on infants and subsequent consequences in them. This review also highlights the knowledge gaps within these topics.

Integration of metabolomics and proteomics analysis to explore the mechanism of neurotoxicity induced by receipt of isoniazid and rifampicin in mice

Isoniazid (INH) and rifampicin (RIF) are co-administered in tuberculosis treatment but can cause neurotoxicity, and the mechanism is not known. To explore this mechanism, we employed an integrated approach using metabolomics analysis (MA) and proteomics analysis (PA). Male mice were divided into three groups and administered vehicle (control group), or co-administered INH (120 mg/kg) and RIF (240 mg/kg), for 7 or 14 days. Mice brains were collected for mass spectrometry-based PA and MA plus lipidomics analysis. Measurement of brain levels of malondialdehyde and superoxide dismutase revealed time-dependent brain injury after exposure to INH+RIF for 7 and 14 days. Also, 422 proteins, 35 metabolites, and 21 lipids were dysregulated and identified. MA demonstrated "purine metabolism," "phenylalanine, tyrosine and tryptophan biosynthesis," "biosynthesis of unsaturated fatty acids," "phenylalanine metabolism," and "arginine biosynthesis" to be disturbed significantly. PA demonstrated pathways such as "lipids," "amino acids," and "energy metabolism" to be disrupted. Peroxisome proliferator-activated receptor (PPAR) pathways were changed in energy metabolism, which led to the neurotoxicity induced by INH+RIF. Immunohistochemical analyses of PPARs in mice brains verified that PPAR-α and -γ expression was downregulated. PPAR-α and -γ activation might be a key target for alleviating INH+RIF-induced neurotoxicity.

Synthesis of Mixed Dinucleotides by Mechanochemistry

We report the synthesis of vitamin B1, B2, and B3 derived nucleotides and dinucleotides generated either through mechanochemical or solution phase chemistry. Under the explored conditions, adenosine and thiamine proved to be particularly amenable to milling conditions. Following optimization of the chemistry related to the formation pyrophosphate bonds, mixed dinucleotides of adenine and thiamine (vitamin B1), riboflavin (vitamin B2), nicotinamide riboside and 3-carboxamide 4-pyridone riboside (both vitamin B3 derivatives) were generated in good yields. Furthermore, we report an efficient synthesis of the MW+4 isotopologue of NAD⁺ for which deuterium incorporation is present on either side of the dinucleotidic linkage, poised for isotopic tracing experiments by mass spectrometry. Many of these mixed species are novel and present unexplored possibilities to simultaneously enhance or modulate cofactor transporters and enzymes of independent biosynthetic pathways.