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Manganese (Mn) is an essential element for humans and animals including, fish. It is a still poorly studied in aquatic organisms, where it can be noticeably useful for dietary components and also found pollutant in aquatic environment at high concentrations. On the above information, an experiment was delineated to determine the lethal concentration of manganese (Mn) and manganese nanoparticles (Mn-NPs) alone and with high temperature (34 °C) and its effect on various biochemical markers in Pangasianodon hypophthalmus. The median lethal concentration (96-LC50) of Mn alone (111.75 mg L−1) and along with high temperature (110.76 mg L−1), Mn-NPs alone (93.81 mg L−1) and with high temperature (34 °C) (92.39 mg L−1) was determined in P. hypophthalmus. The length and weight of the fish were 6.32 ± 0.23 cm and 7.57 ± 1.35 g. The present investigation used five hundred forty-six fish, including range finding (216 fish) and definitive test (330 fish). The acute definitive doses were applied to assess the effect of oxidative stress, glycolytic biomarkers, protein biomarkers, fish immunity, neurotransmitter, energy level, stress hormone and histopathology. Oxidative stress (catalase, superoxide dismutase, glutathione-s-transferase and glutathione peroxidase), stress biomarkers (lipid peroxidation, cortisol, heat shock protein, and blood glucose), lactate and malate dehydrogenase, alanine and aspartate aminotransferase, a neurotransmitter, glucose-6-phosphate dehydrogenase (G6PDH), ATPase, immune system biomarkers (NBT, total protein, albumin, globulin and A:G ratio) were altered with exposure to Mn and Mn-NPs. The histopathology of the liver and gill were also changed due to exposure to Mn and Mn-NPs. The bioaccumulation of Mn in the liver, gill, kidney, brain and muscle tissues, and experimental water at different intervals of 24, 48, 72 and 96 h were determined. Based on the present results, it is strongly suggested that Mn and Mn-NPs exposure alone and with high temperature (34 °C) enhanced toxicity and altered biochemical and morphological attributes. This study also suggested that essential elements in both forms (inorganic and nano) at higher concentrations of Mn and Mn-NPs lead to pronounced deleterious alteration in cellular and metabolic activities and histopathology of P. hypophthalmus. [ABSTRACT FROM AUTHOR]

Mulberry (Morus alba), a widely distributed economic plant, can withstand long-term flooding stress. However, the regulatory gene network underlying this tolerance is unknown. In the present study, mulberry plants were subjected to submergence stress. Subsequently, mulberry leaves were collected to perform quantitative reverse-transcription PCR (qRT-PCR) and transcriptome analysis. Genes encoding ascorbate peroxidase and glutathione S-transferase were significantly upregulated after submergence stress, indicating that they could protect the mulberry plant from flood damage by mediating ROS homeostasis. Genes that regulate starch and sucrose metabolism; genes encoding pyruvate kinase, alcohol dehydrogenase, and pyruvate decarboxylase (enzymes involved in glycolysis and ethanol fermentation); and genes encoding malate dehydrogenase and ATPase (enzymes involved in the TCA cycle) were also obviously upregulated. Hence, these genes likely played a key role in mitigating energy shortage during flooding stress. In addition, genes associated with ethylene, cytokinin, abscisic acid, and MAPK signaling; genes involved in phenylpropanoid biosynthesis; and transcription factor genes also showed upregulation under flooding stress in mulberry plants. These results provide further insights into the adaptation mechanisms and genetics of submergence tolerance in mulberry plants and could aid in the molecular breeding of these plants. [ABSTRACT FROM AUTHOR]

Preparation for oxidative stress (POS) is a widespread adaptive response to harsh environmental conditions, whose hallmark is the upregulation of antioxidants. In contrast to controlled laboratory settings, animals are exposed to multiple abiotic stressors under natural field conditions. Still, the interplay between different environmental factors in modulating redox metabolism in natural settings remains largely unexplored. Here, we aim to shed light on this topic by assessing changes in redox metabolism in the mussel Brachidontes solisianus naturally exposed to a tidal cycle. We compared the redox biochemical response of mussels under six different natural conditions in the field along two consecutive days. These conditions differ in terms of chronology, immersion/emersion, and solar radiation, but not in terms of temperature. Animals were collected after being exposed to air early morning (7:30), immersed during late morning and afternoon (8:45-15:30), and then exposed to air again late afternoon towards evening (17:45-21:25), in two days. Whole body homogenates were used to measure the activity of antioxidant (catalase, glutathione transferase and glutathione reductase) and metabolic (glucose 6-phosphate dehydrogenase, malate dehydrogenase, isocitrate dehydrogenase and pyruvate kinase) enzymes, reduced (GSH) and disulfide (GSSG) glutathione levels, and oxidative stress markers (protein carbonyl and thiobarbituric acid reactive substances). Air and water temperature remained stable between 22.5 0C and 26 0C during both days. Global solar radiation (GSR) greatly differed between days, with a cumulative GSR of 15,381 kJ/m² for day 1 and 5,489 kJ/m² for day 2, whose peaks were 2,240 kJ/m²/h at 14:00 on day 1 and 952 kJ/m²/h at 12:00 on day 2. Compared with animals underwater, emersion during early morning did not elicit any alteration in redox biomarkers in both days. Air exposure for 4 h in the late afternoon towards evening caused oxidative damage to proteins and lipids and elicited GSH synthesis in animals that had been previously exposed to high GSR during the day. In the following day, when GSR was much lower, exposure to air under the same conditions (duration, time, and temperature) had no effect on any redox biomarker. These findings suggest that air exposure under low-intensity solar radiation is not sufficient to trigger POS in B. solisianus in its natural habitat. Thus, natural UV radiation is possibly a key environmental factor that combined to air exposure induces the POS-response to the stressful event of tidal variation in this coastal species. [ABSTRACT FROM AUTHOR]

This analytical review summarizes literature data and our own research on HSP70-dependent mechanisms of neuroprotection and discusses potential pharmacological agents that can influence HSP70 expression to improve neurological outcomes and effective therapy. The authors formed a systemic concepts of the role of HSP70-dependent mechanisms of endogenous neuroprotection aimed at stopping the formation of mitochondrial dysfunction, activation of apoptosis, desensitization of estrogen receptors, reduction of oxidative and nitrosative stress, prevention of morpho-functional changes in brain cells during cerebral ischemia, and experimentally substantiated new target links for neuroprotection. Heat shock proteins (HSPs) are an evolutionarily integral part of the functioning of all cells acting as intracellular chaperones that support cell proteostasis under normal and various stress conditions (hyperthermia, hypoxia, oxidative stress, radiation, etc.). The greatest curiosity in conditions of ischemic brain damage is the HSP70 protein, as an important component of the endogenous neuroprotection system, which, first of all, performs the function of intracellular chaperones and ensures the processes of folding, holding and transport of synthesized proteins, as well as their degradation, both under normoxic conditions and stress-induced denaturation. A direct neuroprotective effect of HSP70 has been established, which is realized through the regulation the processes of apoptosis and cell necrosis due to a long-term effect on the synthesis of antioxidant enzymes, chaperone activity, and stabilization of active enzymes. An increase in the level of HSP70 leads to the normalization of the glutathione link of the thiol-disulfide system and an increase in the resistance of cells to ischemia. HSP 70 is able to activate and regulate compensatory ATP synthesis pathways during ischemia. It was found that in response to the cerebral ischemia formation, HIF-1a is expressed, which initiates the launch of compensatory mechanisms for energy production. Subsequently, the regulation of these processes switches to HSP70, which "prolongs" the action of HIF- 1a, and also independently maintains the expression of mitochondrial NADdependent malate dehydrogenase activity, thereby maintaining the activity of the malate-aspartate shuttle mechanism for a long time. During ischemia of organs and tissues, HSP70 performs a protective function, which is realized through increased synthesis of antioxidant enzymes, stabilization of oxidatively damaged macromolecules, and direct anti-apoptotic and mitoprotective action. Such a role of these proteins in cellular reactions during ischemia raises the question of the development of new neuroprotective agents which are able to provide modulation/protection of the genes encoding the synthesis of HSP 70 and HIF- 1a proteins. Numerous studies of recent years have noted the important role of HSP70 in the implementation of the mechanisms of metabolic adaptation, neuroplasticity and neuroprotection of brain cells, so the positive modulation of the HSP70 system is a perspective concept of neuroprotection, which can improve the efficiency of the treatment of ischemic-hypoxic brain damage and be the basis for substantiating of the feasibility of using of HSP70 modulators as promising neuroprotectors. [ABSTRACT FROM AUTHOR]

The concerted regulation of chloroplast biosynthetic pathways and NADPH extrusion via malate valve depends on f and m thioredoxins (Trxs). The finding that decreased levels of the thiol-peroxidase 2-Cys peroxiredoxin (Prx) suppress the severe phenotype of Arabidopsis mutants lacking NADPH-dependent Trx reductase C (NTRC) and Trxs f uncovered the central function of the NTRC-2-Cys-Prx redox system in chloroplast performance. These results suggest that Trxs m are also regulated by this system; however, the functional relationship between NTRC, 2-Cys Prxs, and m-type Trxs is unknown. To address this issue, we generated Arabidopsis thaliana mutants combining deficiencies in NTRC, 2-Cys Prx B, Trxs m1, and m4. The single trxm1 and trxm4 mutants showed a wild-type phenotype, growth retardation being noticed only in the trxm1m4 double mutant. Moreover, the ntrc-trxm1m4 mutant displayed a more severe phenotype than the ntrc mutant, as shown by the impaired photosynthetic performance, altered chloroplast structure, and defective light-dependent reduction in the Calvin–Benson cycle and malate-valve enzymes. These effects were suppressed by the decreased contents of 2-Cys Prx, since the quadruple ntrc-trxm1m4-2cpb mutant displayed a wild-type-like phenotype. These results show that the activity of m-type Trxs in the light-dependent regulation of biosynthetic enzymes and malate valve is controlled by the NTRC-2-Cys-Prx system. [ABSTRACT FROM AUTHOR]

Plasma-activated liquid is a novel non-thermal antibacterial agent against a wide spectrum of foodborne bacteria, yet fewer studies focused on its disinfection of meat spoilage bacteria. In this study, the antibacterial properties of plasma-activated lactic acid (PALA) on Pseudomonas lundensis, isolated and identified from spoilage beef, were investigated. A plasma jet was used to treat lactic acid (0.05–0.20%) for 60–120 s. The results presented that the 0.2% LA solution treated with plasma for 120 s caused a 5.64 log reduction. Additionally, the surface morphology, membrane integrity and permeability were altered slightly and verified by scanning electron microscopy, double staining of SYTO-9 and propidium iodide, and a K+ test kit. The intracellular organization of the cells, observed by transmission electron microscopy, was damaged significantly. Increased intracellular reactive oxygen species (ROS) levels exceeded the antioxidant ability of glutathione (GSH), leading to a reduction in the activity of malate dehydrogenase (MDH), succinic dehydrogenase (SDH) and intracellular ATP levels. Metabolomics analysis indicated that the energy and synthesis of essential components, such as DNA and amino acid-related metabolic pathways, were disturbed. In conclusion, this research established a theoretical basis for the use of PALA in refrigerated beef preservation by shedding light on the bacteriostatic effect of PALA against Pseudomonas lundensis. [ABSTRACT FROM AUTHOR]

Malate dehydrogenase (MDH) plays an important role in the conversion of malate to oxaloacetate during the tricarboxylic acid cycle. In this study, we examined the role of cytoplasmic MDH (MDH1) in hydrogen peroxide (H2O2)-induced oxidative stress in HT22 cells and ischemia-induced neuronal damage in the gerbil hippocampus. The Tat-MDH1 fusion protein was constructed to enable the delivery of MDH1 into the intracellular space and penetration of the blood–brain barrier. Tat-MDH1, but not MDH1 control protein, showed significant cellular delivery in HT22 cells in a concentration- and time-dependent manner and gradual intracellular degradation in HT22 cells. Treatment with 4 μM Tat-MDH1 significantly ameliorated 200 μM H2O2-induced cell death, DNA fragmentation, and reactive oxygen species formation in HT22 cells. Transient increases in MDH1 immunoreactivity were detected in the hippocampal CA1 region 6–12 h after ischemia, but MDH1 activity significantly decreased 2 days after ischemia. Supplementation of Tat-MDH1 immediately after ischemia alleviated ischemia-induced hyperlocomotion and neuronal damage 1 and 4 days after ischemia. In addition, treatment with Tat-MDH1 significantly ameliorated the increases in hydroperoxides, lipid peroxidation, and reactive oxygen species 2 days after ischemia. Tat-MDH1 treatment maintained the redox status of the glutathione system in the hippocampus 2 days after ischemia. These results suggest that Tat-MDH1 exerts neuroprotective effects by reducing oxidative stress and maintaining glutathione redox system in the hippocampus. [ABSTRACT FROM AUTHOR]

Feed is one of the major inputs in aquaculture system and constitutes 60%–80% of total production costs of tilapia. Inappropriate selection of feed quality and the feeding strategy affects the feed utilization resulting in high food conversion ratio (FCR). A 60 days experiment was conducted to evaluate the growth performance and immuno-physiological responses of GIFT tilapia, (Oreochromis niloticus) by pulsed feeding under biofloc culture system in inland saline water. For the experiment, feeding pattern in pulsed was followed viz., in situ biofloc with daily feeding (T1), in situ biofloc with alternate day feeding (T2), in situ biofloc with every third day feeding (T3), in situ biofloc with no feeding (T4), and clear water control with daily feeding (C) each in triplicates. Biofloc based treatment receiving daily feeding (T1) resulted in significantly (P < 0.05) higher average body weight, weight gain, and specific growth rate (SGR) compared to control. T1 and C showed a significantly similar feed conversion ratio (FCR) and protein efficiency ratio (PER). Fish maintained in T4 grew the least and survival was lowest (85%). The immunological parameters showed a significant difference (P < 0.05) for nitroblue tetrazolium (NBT) and myeloperoxidase content whereas no significant difference (P > 0.05) for lysozyme activity was observed. Higher NBT activity was observed in biofloc based treatments compared to control. Activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activity were considerably higher (P < 0.05) in biofloc based treatments than control. Among biofloc based treatments the antioxidant activities were lower in T1. The carbohydrate metabolism enzymes lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) were lower in T1, T2, and T3 compared to control and T4. In conclusion, in-situ biofloc with daily feeding is found to be effective in growth improvement and to elicit immune-physiological responses in GIFT tilapia under pulsed feeding using biofloc based system. [ABSTRACT FROM AUTHOR]

Malate dehydrogenase (MDH) is a key enzyme in the tricarboxylic acid (TCA) cycle and is essential for energy balance, growth, and tolerance to cold and salt stresses in plants. However, the role of MDH in filamentous fungi is still largely unknown. In this study, we characterized an ortholog of MDH (AoMae1) in a representative nematode-trapping (NT) fungus Arthrobotrys oligospora via gene disruption, phenotypic analysis, and nontargeted metabolomics. We found that the loss of Aomae1 led to a weakening of MDH activity and ATP content, a remarkable decrease in conidia yield, and a considerable increase in the number of traps and mycelial loops. In addition, the absence of Aomae1 also caused an obvious reduction in the number of septa and nuclei. In particular, AoMae1 regulates hyphal fusion under low nutrient conditions but not in nutrient-rich conditions, and the volumes and sizes of the lipid droplets dynamically changed during trap formation and nematode predation. AoMae1 is also involved in the regulation of secondary metabolites such as arthrobotrisins. These results suggest that Aomae1 has an important role in hyphal fusion, sporulation, energy production, trap formation, and pathogenicity in A. oligospora. Our results enhance the understanding of the crucial role that enzymes involved in the TCA cycle play in the growth, development, and pathogenicity of NT fungi. [ABSTRACT FROM AUTHOR]

Malate transporter proteins (MTPs) play a pivotal role in regulating flux in the citrate/malate/pyruvate shuttle to deliver acetyl-CoA from the mitochondria to the cytosol and thus regulate lipid biosynthesis in oleaginous fungi. Despite the recent successful exploration of the mitochondrial malate transporters in Mucor circinelloides, research with in silico analyses that include molecular docking and their dynamics, in addition to homology modelling of malate transporters, have not been reported. In this study, the physico-chemical properties and nucleotide sequence analysis of two mitochondrial MTPs (MT and SoDIT-a with Gene/protein ID scafold00018.48 and scafold00239.15, respectively), in M. circinelloides WJ11 were performed. The three-dimensional (3D) model of the mitochondrial MTPs was determined and the best-docked complex stabilities were demonstrated with molecular dynamic (MD) simulations. The activity domain was revealed to form hydrogen bonds and piling interactions with citrate and malate upon docking. Our study showed better binding affinities for the MTPs—reaching up to −3.44 and −7.27 kcal/mol with the MT and SoDIT-a proteins, respectively (compared to the target of −2.85 and −6.00 kcal/mol for citric acid-binding). MD simulations illustrated that the protein complexes demonstrated conformational stability throughout the simulation. This study was the first to elucidate the structural characteristics of mitochondrial MTPs in M. circinelloides WJ11, providing direct evidence regarding the transport mechanism of specific substrates. Furthermore, the current results support ongoing efforts to combine functional and structural data to better understand the MTPs (at the molecular and atomic levels) of an oleaginous fungus such as M. circinelloides. [ABSTRACT FROM AUTHOR]

Background: This experiment aimed to investigate effects of dietary l‐theanine supplementation on pork quality and muscle fiber type transformation in finishing pigs. In a 30‐day experiment, 18 healthy Duroc × Landrace × Yorkshire (DLY) pigs with an average body weight of 86.03 ± 0.83 kg were randomly divided into three groups (a basal diet or a basal diet supplemented with 500 and 1000 ppm l‐theanine, respectively), with six duplicates and one pig per replicate. Results: The results showed that dietary 1000 ppm l‐theanine supplementation significantly reduced (P < 0.05) b*24 h and drip loss. Dietary 1000 ppm l‐theanine supplementation significantly increased (P < 0.05) slow myosin heavy chain (MyHC) protein expression and the percentage of slow‐twitch fibers, as well as significantly decreased (P < 0.05) fast MyHC protein expression and the percentage of fast‐twitch fibers, accompanied by an increase in succinate dehydrogenase (SDH) and malate dehydrogenase (MDH) activities and a decrease in lactate dehydrogenase (LDH) activity. In addition, the adenosine monophosphate (AMP)‐activated protein kinase (AMPK) signaling pathway was activated by l‐theanine. Conclusion: Together, this study demonstrated for the first time that dietary supplementation of 1000 ppm l‐theanine can improve pork color and drip loss and promote muscle fiber type transformation from fast‐twitch to slow‐twitch in finishing pigs. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Course-based undergraduate research experiences (CUREs) are laboratory courses that integrate broadly relevant problems, discovery, use of the scientific process, collaboration, and iteration to provide more students with research experiences than is possible in individually mentored faculty laboratories. Members of the national Malate dehydrogenase CUREs Community (MCC) investigated the differences in student impacts between traditional laboratory courses (control), a short module CURE within traditional laboratory courses (mCURE), and CUREs lasting the entire course (cCURE). The sample included approximately 1,500 students taught by 22 faculty at 19 institutions. We investigated course structures for elements of a CURE and student outcomes including student knowledge, student learning, student attitudes, interest in future research, overall experience, future GPA, and retention in STEM. We also disaggregated the data to investigate whether underrepresented minority (URM) outcomes were different from White and Asian students. We found that the less time students spent in the CURE the less the course was reported to contain experiences indicative of a CURE. The cCURE imparted the largest impacts for experimental design, career interests, and plans to conduct future research, while the remaining outcomes were similar between the three conditions. The mCURE student outcomes were similar to control courses for most outcomes measured in this study. However, for experimental design, the mCURE was not significantly different than either the control or cCURE. Comparing URM and White/Asian student outcomes indicated no difference for condition, except for interest in future research. Notably, the URM students in the mCURE condition had significantly higher interest in conducting research in the future than White/Asian students. [ABSTRACT FROM AUTHOR]

This study evaluated the genetic damage, oxidative stress, neurotoxicity, and energy metabolism in bullfrog tadpoles (Lithobates catesbeianus) exposed to water from two sites of the Sorocaba River, Ibiúna (PI), and Itupararanga reservoir (PIR), in summer and winter. After 96-h exposure, the erythrocyte number decreased in PI and increase in PIR in summer. Bullfrogs show oxidative unbalance (liver, kidney, and muscle), with alterations in the nitric oxide synthase and glucose 6-phosphate dehydrogenase. Cholinesterase increased in the brain in PI and PIR in the summer and decreased in PI in the winter. It also increased in the muscle in both PI and PIR in the winter. Tadpoles show alterations in the activity of the metabolic enzymes (liver, kidney, and muscle), such as phosphofructokinase, pyruvatokinase, malate dehydrogenase, and lactate dehydrogenase; and in the amount of glucose and triglycerides metabolites. Exposure to the Sorocaba River reflected a stressful situation for L. catesbeianus as the changes caused to their metabolism associated with oxidative stress and neurotoxicity may have effects on the development of tadpoles. [ABSTRACT FROM AUTHOR]

Aims This study aimed to investigate the mechanism of linalool against Pseudomonas lundensis and its application on beef. Methods and Results Field emission scanning electron microscopy found that linalool exerted antibacterial activity with a minimum inhibitory concentration (MIC) of 1.5 ml l−1 by disrupting cell structure. Loss of cell membrane integrity was monitored due to leakage of nucleic acids and K+. In addition, respiratory depression appeared in Ps. lundensis based on inhibition of enzyme activities including hexokinase (HK), glucose 6-phosphate dehydrogenase (G6PDH), phosphofructokinase (PFK), pyruvate kinase (PK), pyruvate dehydrogenase (PDH), citrate synthase (CS), succinate dehydrogenase (SDH), and malate dehydrogenase (MDH). Subsequently, energy limitation also occurred according to the decrease in ATP content and ATPase activity. Molecular docking confirmed that linalool can combine with enzymes in cell wall (ddlB) and energy synthesis (AtpD) pathways to exert antibacterial effect. Of note, linalool has advantages for beef preservation by delaying quality changes including pH, total volatile basic nitrogen (TVB-N) and total viable count (TVC). Conclusions Linalool has significant inhibitory effect on Ps. lundensis , and respiratory depression driven by membrane damage is the main inhibitory mechanism. [ABSTRACT FROM AUTHOR]

Malate dehydrogenase (MDH) genes play vital roles in developmental control and environmental stress tolerance in sessile plants by modulating the organic acid–malic acid level. However, MDH genes have not yet been characterized in gymnosperm, and their roles in nutrient deficiency are largely unexplored. In this study, 12 MDH genes were identified in Chinese fir (Cunninghamia lanceolata), namely, ClMDH-1, -2, -3, ..., and -12. Chinese fir is one of the most abundant commercial timber trees in China, and low phosphorus has limited its growth and production due to the acidic soil of southern China. According to the phylogenetic analysis, MDH genes were classified into five groups, and Group 2 genes (ClMDH-7, -8, -9, and 10) were only found to be present in Chinese fir but not in Arabidopsis thaliana and Populus trichocarpa. In particular, the Group 2 MDHs also had specific functional domains—Ldh_1_N (malidase NAD-binding functional domain) and Ldh_1_C (malate enzyme C-terminal functional domain)—indicating a specific function of ClMDHs in the accumulation of malate. All ClMDH genes contained the conserved MDH gene characteristic functional domains Ldh_1_N and Ldh_1_C, and all ClMDH proteins exhibited similar structures. Twelve ClMDH genes were identified from eight chromosomes, involving fifteen ClMDH homologous gene pairs, each with a Ka/Ks ratio of <1. The analysis of cis-elements, protein interactions, and transcription factor interactions of MDHs showed that the ClMDH gene might play a role in plant growth and development, and in response to stress mechanisms. The results of transcriptome data and qRT-PCR validation based on low-phosphorus stress showed that ClMDH1, ClMDH6, ClMDH7, ClMDH2, ClMDH4, ClMDH5, ClMDH10 and ClMDH11 were upregulated under low-phosphorus stress and played a role in the response of fir to low-phosphorus stress. In conclusion, these findings lay a foundation for further improving the genetic mechanism of the ClMDH gene family in response to low-phosphorus stress, exploring the potential function of this gene, promoting the improvement of fir genetics and breeding, and improving production efficiency. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa PAO1 D-2-hydroxyglutarate (D2HG) dehydrogenase (PaD2HGDH) oxidizes D2HG to 2-ketoglutarate during the vital L-serine biosynthesis and is a potential therapeutic target against P. aeruginosa. PaD2HGDH, which oxidizes D-malate as an alternative substrate, has been demonstrated to be a metallo flavoprotein that requires Zn2+ for activity. However, the role of Zn2+ in the enzyme has not been elucidated, making it difficult to rationalize why nature employs both a redox center and a metal ion for catalysis in PaD2HGDH and other metallo flavoenzymes. In this study, recombinant His-tagged PaD2HGDH was purified to high levels in the presence of Zn2+ or Co2+ to investigate the metal's role in catalysis. We found that the flavin reduction step was reversible and partially rate limiting for the enzyme's turnover at pH 7.4 with either D2HG or D-malate with similar rate constants for both substrates, irrespective of whether Zn2+ or Co2+ was bound to the enzyme. The steady-state pL profiles of the kcat and kcat/Km values with D-malate demonstrate that Zn2+ mediates the activation of water coordinated to the metal. Our data are consistent with a dual role for the metal, which orients the hydroxy acid substrate in the enzyme's active site and rapidly deprotonates the substrate to yield an alkoxide species for hydride transfer to the flavin. Thus, we propose a catalytic mechanism for PaD2HGDH oxidation that establishes Zn2+ as a cofactor required for substrate orientation and activation during enzymatic turnover. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa couples the oxidation of D-2-hydroxyglutarate (D2HG) to L-serine biosynthesis for survival, using D-2-hydroxyglutarate dehydrogenase from P. aeruginosa (PaD2HGDH). Knockout of PaD2HGDH impedes P. aeruginosa growth, making PaD2HGDH a potential target for therapeutics. Previous studies showed that the enzyme's activity increased with Zn2+, Co2+, or Mn2+ but did not establish the enzyme's metal composition and whether the metal is an activator or a required cofactor for the enzyme, which we addressed in this study. Comparable to the human enzyme, PaD2HGDH showed only 15% flavin reduction with D2HG or D-malate. Upon purifying PaD2HGDH with 1 mM Zn2+, the Zn2+:protein stoichiometry was 2:1, yielding an enzyme with -40 s-1 kcat for D-malate. Treatment with 1 mM EDTA decreased the Zn2+:protein ratio to 1:1 without changing the kinetic parameters with D-malate. We observed complete enzyme inactivation for the metalloapoenzyme with 100 mM EDTA treatment, suggesting that Zn2+ is essential for PaD2HGDH activity. The presence of Zn2+ increased the flavin N3 atom pKa value to 11.9, decreased the flavin e450 at pH 7.4 from 13.5 to 11.8 mM-1 cm-1, and yielded a charged transfer complex with a broad absorbance band >550 nm, consistent with a Zn2+-hydrate species altering the electronic properties of the enzyme-bound FAD. The exogenous addition of Zn2+, Co2+, Cd2+, Mn2+, or Ni2+ to the metalloapoenzyme reactivated the enzyme in a sigmoidal pattern, consistent with an induced fit rapid-rearrangement mechanism. Collectively, our data demonstrate that PaD2HGDH is a Zn2+-dependent metallo flavoprotein, which requires Zn2+ as an essential cofactor for enzyme activity. [ABSTRACT FROM AUTHOR]

Fusarium culmorum (Fc) is a hemibiotrophic plant fungal pathogen that causes crown and root rot disease in wheat. In this study, for the first time, a comparative proteomic analysis was made in seedling roots of two wheat cultivars Falat (susceptible) and Sumai3 (resistant) to understand defense responses induced during the early stage of Fc-infection. The patterns of differentially expressed protein spots (DEPs) were located on two-dimensional gel electrophoresis 48 h after F. culmorum inoculation and a total of 30 major protein spots were successfully identified by mass spectrometry. These proteins were grouped into diverse functional categories which were involved in cellular metabolism (70%), defense (10%), energy (10%) and cell structure (3%), while only two proteins were unknown (7%). Seven DEPs were equally up-regulated with significant expression changes in both cultivars, while seventeen DEPs such as isocitrate dehydrogenase, malate dehydrogenase, enolase which are related to cellular respiration besides lipoxygenase that is vital enzyme in jasmonate biosynthesis were up-regulated only in Sumai3. Likewise, RuBisCO, as a photosynthesis responsive DEPs, showed significantly higher abundance only in Falat. These results showed that the resistant cultivar provides required energy for combating pathogen by reducing photosynthesis and increasing cellular respiration during early stage of Fc-infection. Moreover, lipoxygenase as main marker of octadecanoid pathways solitary increased in resistant cv. Sumai3 and there is a direct correlation between expressed proteins and level of defense responses to crown and root rot disease in wheat. [ABSTRACT FROM AUTHOR]

In ruminant livestock production, ruminal acidosis is an unintended consequence of the elevated dietary intake of starch-rich feedstuffs. The transition from a state of subacute acidosis (SARA) to acute acidosis is due in large part to the accumulation of lactate in the rumen, which is a consequence of the inability of lactate utilizers to compensate for the increased production of lactate. In this report, we present the 16S rRNA gene-based identification of two bacterial operational taxonomic units (OTUs), Bt-01708_Bf (89.0% identical to Butyrivibrio fibrisolvens) and Bt-01899_Ap (95.3% identical to Anaerococcus prevotii), that were enriched from rumen fluid cultures in which only lactate was provided as an exogenous substrate. Analyses of in-silico-predicted proteomes from metagenomics-assembled contigs assigned to these candidate ruminal bacterial species (Bt-01708_Bf: 1270 annotated coding sequences, 1365 hypothetical coding sequences; Bt-01899_Ap: 871 annotated coding sequences, 1343 hypothetical coding sequences) revealed genes encoding lactate dehydrogenase, a putative lactate transporter, as well as pathways for the production of short chain fatty acids (formate, acetate and butyrate) and for the synthesis of glycogen. In contrast to these shared functions, each OTU also exhibited distinct features, such as the potential for the utilization of a diversified set of small molecules as substrates (Bt-01708_Bf: malate, quinate, taurine and polyamines) or for the utilization of starch (Bt-01899_Ap: alpha-amylase enzymes). Together, these results will contribute to the continued characterization of ruminal bacterial species that can metabolize lactate into distinct subgroups based on other metabolic capabilities. [ABSTRACT FROM AUTHOR]

Green algae produce valuable lipids as carbon-recycling resources. Collecting whole cells with the intracellular lipids could be efficient without cell burst; however, direct use of the cells causes microbial contamination in environments. Then, UV-C irradiation was selected to satisfy the requirements of avoiding the cell burst and sterilizing cells with Chlamydomonas reinhardtii. UV-C irradiation with 1.209 mW·cm−2 showed enough sterilization activity for 1.6 × 107 cells·mL−1 of C. reinhardtii in a depth of 5 mm for 10 min. The irradiation showed no effects to composition and contents of the intracellular lipids. From the viewpoint of transcriptomic analysis, the irradiation displayed possibilities of (i) inhibition of the synthesis of lipids due to decrement of the transcription of related genes, such as diacylglycerol acyl transferase and cyclopropane fatty acid synthase, and (ii) activation of lipid degradation and the production of NADH2+ and FADH2 due to increment of the transcription of related genes, such as isocitrate dehydrogenase, dihydrolipoamide dehydrogenase and malate dehydrogenase. Irradiation until cell death could be insufficient to shift the metabolic flows even though the transcriptions were already shifted to lipid degradation and energy production. This paper is the first report of the response of C. reinhardtii to UV-C irradiation on the transcription level. [ABSTRACT FROM AUTHOR]

In this experiment, the effect of salt stress on the root proteome pattern of Arg (tolerant to salinity) and Moghan3 (sensitive to salinity) cultivars of wheat was investigated by two-dimensional polyacrylamide gel electrophoresis. Salinity was applied at two levels of 0 and 150 mM in the third-leaf stage for three weeks under greenhouse conditions. The proteome analysis of the roots revealed 120 reproducible protein spots, among which 15 spots showed significant changes in expression. In Moghan3, four protein spots with a significant reduction in expression were identified. In the tolerant cultivar of Arg, 11 protein spots showed significant changes in expression, among which five protein spots had an increased expression and six protein spots had a decreased expression. These proteins were classified based on their function into several groups such as the proteins involved in metabolism and energy, reactive oxygen species scavenging and detoxification, the proteins associated with cell walls, and the proteins involved in folding and degradation. Probably, the tolerance to salt stress in the Arg cultivar was related to the increased expression of pyruvate dehydrogenase, phosphoglycerate mutase, catalase, and malate dehydrogenase proteins. While in the sensitive variety of Moghan3, the decrease in the expression of enolase, peroxidase, and glutathione peroxidase proteins under salinity stress conditions probably caused oxidative stress in the plants due to increased production of reactive oxygen species. These findings can be useful for improving the salt tolerance in the breeding programs of wheat. [ABSTRACT FROM AUTHOR]

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Antibacterial resistance has become one of the most serious problems threating global health. To overcome this urgent problem, many scientists have paid great attention to developing new antibacterial drugs from natural products. Hence, for exploring new antibacterial drugs from Chinese medicine, a series of experiments were carried out for verifying and elucidating the antibacterial activity and mechanisms of madecassic acid (MA), which is an active triterpenoid compound isolated from the traditional Chinese medicine, Centella asiatica. The antibacterial activity was investigated through measuring the diameter of the inhibition zone, the minimum inhibitory concentration (MIC), the growth curve, and the effect on the bacterial biofilm, respectively. Meanwhile, the antibacterial mechanism was also discussed from the aspects of cell wall integrity variation, cell membrane permeability, and the activities of related enzymes in the respiratory metabolic pathway before and after the intervention by MA. The results showed that MA had an inhibitory effect on eight kinds of pathogenic bacteria, and the MIC values for Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Bacillus megaterium were 31.25, 62.5, 250, 125, 62.5, and 62.5 µg/mL, respectively. For instance, 31.25 µg/mL MA could inhibit the growth of Staphylococcus aureus within 28 h. The antibacterial mechanism experiments confirmed that MA could destroy the integrity of the cell membrane and cell wall of Staphylococcus aureus, causing the leakage of macromolecular substances, inhibiting the synthesis of soluble proteins, reducing the activities of succinate dehydrogenase and malate dehydrogenase, and interacting with DNA, leading to the relaxation and ring opening of supercoiled DNA. Besides, the activities of DNA topoisomerase I and II were both inhibited by MA, which led to the cell growth of Staphylococcus aureus being repressed. This study provides a theoretical basis and reference for the application of MA in the control and inhibition of food-borne Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

The present study evaluated the effects of supplemental dietary α-linolenic acid (ALA, 18:3n-3) on growth performance, body composition, hepatic fat metabolizing enzymes, and fatty acid profiles of coho salmon (Oncorhynchus kisutch) alevins cultured in freshwater. Six isonitrogenous and isolipidic experimental diets were formulated to attain different levels of ALA (0.09, 0.41, 0.76, 1.03, 1.32, and 1.68% dry weight) by adding linseed oil in a basal diet, respectively. Each diet was fed to triplicate groups of alevins (50 fish in each tank) with initial mean body weight of 0.352 ± 0.002 g. Fish were reared in a freshwater flow-through rearing system and fed to apparent satiation 4 times daily for 12 weeks. The specific growth rate (SGR) increased with increasing dietary ALA level, which reached the peak at 1.03% ALA group (p < 0.05). The final body weight (FBW) and SGR showed linear, quadratic, and cubic responses with the dietary ALA level. The whole-body crude protein increased with increasing dietary ALA level while lipid content was the opposite trend (p < 0.05). However, the content of crude lipid in the whole-body of fish showed quadratic and cubic responses with the dietary ALA level. In addition, except for fatty acid synthase (FAS), the hepatic enzymes activities of lipoprotein lipase (LPL), hepatic lipase (HL), and malate dehydrogenase (MDH) showed linear, quadratic, and cubic response with the dietary ALA level (p < 0.05) The activities of hepatic LPL and HL in 1.32% ALA group were significantly higher than other groups (p < 0.05). The activities of hepatic MDH and FAS in 1.32% ALA group were the lowest, which were significantly lower than those in ALA groups (form 0.09% to1.03%) (p < 0.05). Except for the content of MUFA, the contents of other fatty acids showed linear, quadratic, and cubic response with the dietary ALA level. The ALA and ∑n-3 PUFA content significantly increased with increasing dietary ALA levels (p < 0.05). These results indicated that dietary ALA actively impacted fish growth performance, hepatic lipid metabolizing enzymes, and muscle fatty acid profile. The cubic regression analysis based on SGR as evaluation indices indicated that the optimal dietary ALA content was 1.33% dry weight of diet for alevins. [ABSTRACT FROM AUTHOR]

Through agronomic traits and sequencing data, the cultivated and wild varieties of grapes and peaches were analyzed and compared in terms of fruit size, fruit flavor, fruit resistance, and fruit color. Cultivated grapes and peaches have advantages in fruit size, soluble sugar content, sugar and acid ratio, etc. Wild grapes and peaches have utility value in resistance. The results showed that there were 878 and 301 differentially expressed genes in cultivated and wild grapes and peaches in the three growth stages, respectively based on the next-generation sequencing study. Ten and twelve genes related to the differences between cultivated and wild grapes and peaches were found respectively. Among them, three genes, namely chalcone synthase (CHS), glutathione S-transferase (GST) and malate dehydrogenase (MDH1) were present in both cultivated and wild grapes and peaches. [ABSTRACT FROM AUTHOR]

Malate is an important material to various industrials and clinical applications. Bacillus subtilis is a widely used biocatalyst tool for chemical production. However, the specific enzymatic properties of malate dehydrogenase from Bacillus subtilis (BsMDH) remain largely unknown. In the present study, BsMDH was cloned, recombinantly expressed and purified to test its enzymatic properties. The molecular weight of single unit of BsMDH was 34,869.7 Da. Matrix-Assisted Laser-Desorption Ionization-Time-of-Flight Mass Spectrometry and gel filtration analysis indicated that the recombinant BsMDH could form dimers. The kcat/Km values of oxaloacetate and NADH were higher than those of malate and NAD+, respectively, indicating a better catalysis in the direction of malate synthesis than the reverse. Furthermore, six BsMDH mutants were constructed with the substitution of amino acids at the coenzyme binding site. Among them, BsMDH-T7 showed a greatly higher affinity and catalysis efficiency to NADPH than NADH with the degree of alteration of 2039, suggesting the shift of the coenzyme dependence from NADH to NADPH. In addition, BsMDH-T7 showed a relatively lower Km value, but a higher kcat and kcat/Km than NADPH-dependent MDHs from Thermus flavus and Corynebacterium glutamicum. Overall, these results indicated that BsMDH and BsMDH-T7 mutant might be promising enzymes for malate production. [ABSTRACT FROM AUTHOR]

Cold acclimation is a multigenic process by which many plant species increase their freezing tolerance. Stabilization of photosynthesis and carbohydrate metabolism plays a crucial role in cold acclimation. To study regulation of primary and secondary metabolism during cold acclimation of Arabidopsis thaliana, metabolic mutants with deficiencies in either starch or flavonoid metabolism were exposed to 4°C. Photosynthesis was determined together with amounts of carbohydrates, anthocyanins, organic acids and enzyme activities of the central carbohydrate metabolism. Starch deficiency was found to significantly delay soluble sugar accumulation during cold acclimation, while starch overaccumulation did not affect accumulation dynamics but resulted in lower total amounts of \sucrose and glucose. Anthocyanin amounts were lowered in both starch deficient and overaccumulating mutants. Vice versa, flavonoid deficiency did not result in a changed starch amount, which suggested a unidirectional signalling link between starch and flavonoid metabolism. Mathematical modelling of carbon metabolism indicated kinetics of sucrose biosynthesis to be limiting for carbon partitioning in leaf tissue during cold exposure. Together with cold‐induced dynamics of citrate, fumarate and malate amounts, this provided evidence for a central role of sucrose phosphate synthase activity in carbon partitioning between biosynthetic and dissimilatory pathways which stabilizes photosynthesis and metabolism at low temperature. Summary Statement: Regulation at the interface of plant primary and secondary metabolism during cold acclimation was analysed by kinetic modelling. Our findings suggest that cold‐induced limitation of sucrose biosynthesis regulates substrate availability for the coordinated accumulation of starch and anthocyanins. [ABSTRACT FROM AUTHOR]

Somatic mutations in the isoenzymes of isocitrate dehydrogenases (IDHs) account for the pathogenesis of various malignancies including gliomas. To date, ivosidenib is the only FDA-approved drug candidate widely used to target mutated isocitrate dehydrogenase 1 (mIDH1). However, the impotence of the existing drug to evade the blood barrier remains an obstacle to harness ivosidenib as therapeutics against glioma. Thus, in this study, we elucidate a fragment-based drug discovery strategy to design novel lead molecules against the mIDH1 protein. Initially, a fragment library was constructed using 27 known mIDH1 inhibitors from the literature. The vast chemical classes of constructed library consisting of 1109 fragments were then used for breeding. A total of 18,000 breed compounds were generated and the resultant compounds were scrutinized based on the breed score (> 1 2) and Tanimoto coefficient (Tc ≥ 0. 5). The binding affinity and the energetics of the resultant molecules (2069) were investigated using molecular docking and MM-GBSA calculations. Eventually, the compounds with higher affinity were included in the mutational analysis incorporating the second site mutations namely IDH1S280F and IDH1R119P. The bioavailability analysis and toxicity profiling were carried out for screened hybrid molecules. The pipeline of the integrated in-silico approach identified hybrid 209, hybrid 237 and hybrid 504 as the drug-like candidates against the mutational variants of mIDH1 protein. Interestingly, all three compounds exhibited greater binding affinity and better brain penetrating capability. The machine learning-based anti-cancerous sensitivity prediction tool affirmed the inhibitory effect of the resultant hits against various glioma cell lines. In the end, the structural stability of the screened molecules was examined using the molecular dynamic simulation study for a stipulated time of 100 ns. Indeed, this evidence speculates that the identified hybrid molecules could serve as important leads for the management of glioma in the near future. The fragment-based drug designing strategy was employed to identify novel hybrid molecules against mIDH1 protein. Indeed the results are of immense importance for management of glioma in the near future. [ABSTRACT FROM AUTHOR]

Cowden syndrome (CS) is a rare hereditary hamartoma‐cancer disorder related to germline mutations in the tumor suppressor phosphatase and tensin homolog (PTEN) gene. Association of CS with intracranial tumors, apart from Lhermitte‐Duclos disease (LDD), is not well recognized. We present an exceptional instance of concomitant meningioma and glioblastoma in CS, the first case ever reported. Following a new‐onset seizure, a 62‐year‐old male harboring the PTEN gene germline mutation c.334C > G was diagnosed with multiple brain tumors, which were erroneously thought to correspond to metastases. Because no primary cancer was found, an operation was proposed for histopathological diagnosis. Examination of surgical specimens obtained from the two lesions removed, one extra‐axial and the other intracerebral, demonstrated a metaplastic meningioma with a lipomatous appearance and an isocitrate dehydrogenase wild‐type glioblastoma, respectively. Loss of the PTEN gene expression was demonstrated immunohistochemically in both lesions, a finding that supports their relation to CS. A thorough literature review revealed only 25 additional CS patients with intracranial tumors other than LDD. All of them corresponded to primary lesions, with meningiomas accounting for 76% of the cases (19 patients), followed by pituitary tumors (three cases) and glioblastomas (two patients from the same family). Our report and literature review highlight the association between CS and primary brain tumors rather than metastasis. For judicious management of a CS patient with multiple intracranial tumors, different primary brain pathological entities should also be suspected first before considering metastasis. Close neurological monitoring and brain magnetic resonance imaging are advocated as part of the cancer screening in CS patients, particularly in cases with a family history of intracranial tumors. [ABSTRACT FROM AUTHOR]

The conversion of skeletal muscle fiber from fast-twitch to slow-twitch is crucial for sustained contractile and stretchable events, energy homeostasis, and anti-fatigue ability. The purpose of our study was to explore the mechanism and effects of garcinol on the regulation of skeletal muscle fiber type transformation. Forty 21-day-old male C57/BL6J mice (n = 10/diet) were fed a control diet or a control diet plus garcinol at 100 mg/kg (Low Gar), 300 mg/kg (Mid Gar), or 500 mg/kg (High Gar) for 12 weeks. The tibialis anterior (TA) and soleus muscles were collected for protein and immunoprecipitation analyses. Dietary garcinol significantly downregulated (p < 0.05) fast myosin heavy chain (MyHC) expression and upregulated (p < 0.05) slow MyHC expression in the TA and soleus muscles. Garcinol significantly increased (p < 0.05) the activity of peroxisome proliferator-activated receptor gamma co-activator 1α (PGC-1α) and markedly decreased (p < 0.05) the acetylation of PGC-1α. In vitro and in vivo experiments showed that garcinol decreased (p < 0.05) lactate dehydrogenase activity and increased (p < 0.05) the activities of malate dehydrogenase and succinic dehydrogenase. In addition, the results of C2C12 myotubes showed that garcinol treatment increased (p < 0.05) the transformation of glycolytic muscle fiber to oxidative muscle fiber by 45.9%. Garcinol treatment and p300 interference reduced (p < 0.05) the expression of fast MyHC but increased (p < 0.05) the expression of slow MyHC in vitro. Moreover, the acetylation of PGC-1α was significantly decreased (p < 0.05). Garcinol promotes the transformation of skeletal muscle fibers from the fast-glycolytic type to the slow-oxidative type through the p300/PGC-1α signaling pathway in C2C12 myotubes. [ABSTRACT FROM AUTHOR]

Indigo pigment is a widely used pigment, and the use of biosynthesis to ferment indigo has become a hot research topic. Based on previous research, the indigo could be biosynthesized via the styrene oxygenation pathway, which is regulated by intracellular redox-cofactor rebalancing. In this work, the malate dehydrogenase (mdh) gene was selected as an NADH regeneration element to improve the intracellular cofactor regeneration level, and it was co-expressed with the styrene monooxygenase (styAB) gene by pET-28a(+) vector in E. coli for enhancing indigo production. The PT7 and Pcat promoter was constructed to change the styAB gene and mdh gene from inducible expression to constitutive expression, since the expressing vector pET-28a(+) needs to be induced by IPTG. After different strategies of genetic manipulations, the styAB gene and mdh gene were successfully constitutively co-expressed by different promoters in E. coli, which obviously enhanced the monooxygenase activity and indigo production, as expected. The maximum yield of indigo in recombinant strains was up to 787.25 mg/L after 24 h of fermentation using 2.0 g/L tryptophan as substrate, which was nearly the highest indigo-producing ability using tryptophan as substrate in recent studies. In summary, this work provided a theoretical basis for the subsequent study of indigo biosynthesis and probably revealed a new insight into the construction of indigo biosynthesis cell factory for application. [ABSTRACT FROM AUTHOR]

We report the mixotrophic growth of Escherichia coli based on recombinant 2-oxoglutarate:ferredoxin oxidoreductase (OGOR) to assimilate CO2 using malate as an auxiliary carbon source and hydrogen as an energy source. We employ a long-term (~184 days) two-stage adaptive evolution to convert heterotrophic E. coli into mixotrophic E. coli. In the first stage of evolution with serine, diauxic growth emerges as a prominent feature. At the end of the second stage of evolution with malate, the strain exhibits mixotrophy with CO2 as an essential substrate for growth. We expect this work will open new possibilities in the utilization of OGOR for microbial CO2 assimilation and future hydrogen-based electro-microbial conversion. [ABSTRACT FROM AUTHOR]

The present study was carried out to investigate the effects of bamboo leaf extract (BLE) on energy metabolism, antioxidant capacity, and biogenesis of broilers' small intestine mitochondria. A total of 384 one-day-old male Arbor Acres broiler chicks were randomly divided into four groups with six replicates each for 42 d. The control group was fed a basal diet, whereas the BLE1, BLE2, and BLE3 groups consumed basal diets with 1.0, 2.0, and 4.0 g/kg of BLE, respectively. Some markers of mitochondrial energy metabolism including isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, and malate dehydrogenase and some markers of redox system including total superoxide dismutase, malondialdehyde, and glutathione were measured by commercial colorimetric kits. Mitochondrial and cellular antioxidant genes, mitochondrial biogenesis-related genes, and mitochondrial DNA copy number were measured by quantitative real-time-polymerase chain reaction (qRT-PCR). Data were analyzed using the SPSS 19.0, and differences were considered as significant at P < 0.05. BLE supplementation linearly increased jejunal mitochondrial isocitrate dehydrogenase (P < 0.05) and total superoxide dismutase (P < 0.05) activity. The ileal manganese superoxide dismutase mRNA expression was linearly affected by increased dietary BLE supplementation (P < 0.05). Increasing BLE supplementation linearly increased jejunal sirtuin 1 (P < 0.05) and nuclear respiratory factor 1 (P < 0.05) mRNA expression. Linear (P < 0.05) and quadratic (P < 0.05) responses of the ileal nuclear respiratory factor 2 mRNA expression occurred with increased dietary BLE levels. In conclusion, BLE supplementation was beneficial to the energy metabolism, antioxidant capacity, and biogenesis of small intestine mitochondria in broilers. The dose of 4.0 g/kg BLE demonstrated the best effects. [ABSTRACT FROM AUTHOR]

Currently, the biological production of L-malic acid (L-MA) is mainly based on the fermentation of filamentous fungi at near-neutral pH, but this process requires large amounts of neutralizing agents, resulting in the generation of waste salts when free acid is obtained in the downstream process, and the environmental hazards associated with the waste salts limit the practical application of this process. To produce L-MA in a more environmentally friendly way, we metabolically engineered the acid-tolerant yeast Pichia kudriavzevii and achieved efficient production of L-MA through low pH fermentation. First, an initial L-MA-producing strain that relies on the reductive tricarboxylic acid (rTCA) pathway was constructed. Subsequently, the L-MA titer and yield were further increased by fine-tuning the flux between the pyruvate and oxaloacetate nodes. In addition, we found that the insufficient supply of NADH for cytoplasmic malate dehydrogenase (MDH) hindered the L-MA production at low pH, which was resolved by overexpressing the soluble pyridine nucleotide transhydrogenase SthA from E. coli. Transcriptomic and metabolomic data showed that overexpression of EcSthA contributed to the activation of the pentose phosphate pathway and provided additional reducing power for MDH by converting NADPH to NADH. Furthermore, overexpression of EcSthA was found to help reduce the accumulation of the by-product pyruvate but had no effect on the accumulation of succinate. In microaerobic batch fermentation in a 5-L fermenter, the best strain, MA009-10-URA3 produced 199.4 g/L L-MA with a yield of 0.94 g/g glucose (1.27 mol/mol), with a productivity of 1.86 g/L/h. The final pH of the fermentation broth was approximately 3.10, meaning that the amount of neutralizer used was reduced by more than 50% compared to the common fermentation processes using filamentous fungi. To our knowledge, this is the first report of the efficient bioproduction of L-MA at low pH and represents the highest yield of L-MA in yeasts reported to date. • Efficient L-MA production at low pH was achieved in the acid-tolerant yeast P. kudriavzevii. • The L-MA titer and yield were increased by fine-tuning the flux between the pyruvate and oxaloacetate nodes. • The additional supply of NADH was critical for L-MA production at low pH and reduced the by-product accumulation of pyruvate. [ABSTRACT FROM AUTHOR]

Altered metabolism is a hallmark of aging. The tricarboxylic acid cycle (TCA cycle) is an essential metabolic pathway and plays an important role in lifespan regulation. Supplementation of α-ketoglutarate, a metabolite converted by isocitrate dehydrogenase alpha-1 (idha-1) in the TCA cycle, increases lifespan in C. elegans. However, whether idha-1 can regulate lifespan in C. elegans remains unknown. Here, we reported that the expression of idha-1 modulates lifespan and oxidative stress tolerance in C. elegans. Transgenic overexpression of idha-1 extends lifespan, increases the levels of NADPH/NADP+ ratio, and elevates the tolerance to oxidative stress. Conversely, RNAi knockdown of idha-1 exhibits the opposite effects. In addition, the longevity of eat-2 (ad1116) mutant via dietary restriction (DR) was reduced by idha-1 knockdown, indicating that idha-1 may play a role in DR-mediated longevity. Furthermore, idha-1 mediated lifespan may depend on the target of rapamycin (TOR) signaling. Moreover, the phosphorylation levels of S6 kinase (p-S6K) inversely correlate with idha-1 expression, supporting that the idha-1-mediated lifespan regulation may involve the TOR signaling pathway. Together, our data provide new insights into the understanding of idha-1 new function in lifespan regulation probably via DR and TOR signaling and in oxidative stress tolerance in C. elegans. [ABSTRACT FROM AUTHOR]

Biological ageing is connected to life history variation across ecological scales and informs a basic understanding of age‐related declines in organismal function. Altered DNA methylation dynamics are a conserved aspect of biological ageing and have recently been modelled to predict chronological age among vertebrate species. In addition to their utility in estimating individual age, differences between chronological and predicted ages arise due to acceleration or deceleration of epigenetic ageing, and these discrepancies are linked to disease risk and multiple life history traits. Although evidence suggests that patterns of DNA methylation can describe ageing in plants, predictions with epigenetic clocks have yet to be performed. Here, we resolve the DNA methylome across CpG, CHG, and CHH‐methylation contexts in the loblolly pine tree (Pinus taeda) and construct epigenetic clocks capable of predicting ages in this species within 6% of its maximum lifespan. Although patterns of CHH‐methylation showed little association with age, both CpG and CHG‐methylation contexts were strongly associated with ageing, largely becoming hypomethylated with age. Among age‐associated loci were those in close proximity to malate dehydrogenase, NADH dehydrogenase, and 18S and 26S ribosomal RNA genes. This study reports one of the first epigenetic clocks in plants and demonstrates the universality of age‐associated DNA methylation dynamics which can inform conservation and management practices, as well as our ecological and evolutionary understanding of biological ageing in plants. [ABSTRACT FROM AUTHOR]

Mesembryanthemum crystallinum is a model halophyte that switches from C3 photosynthesis to Crassulacean acid metabolism (CAM) upon extreme abiotic stresses. This study aimed to investigate alkalinity-induced root transcriptome profiling in M. crystallinum. M. crystallinum seedlings were treated with 50 mM sodium bicarbonate (NaHCO3; pH 7.5) and 90 mM NaHCO3 (pH 9.5) for 7 d, respectively. Alkalinity-induced differentially expressed genes (DEGs) were identified and annotated. Functional enrichment analysis was performed for DEGs. The expression of genes related to response to stress and CAM were analyzed and compared. Comparing with control, 50 and 90 mM NaHCO3 treatments induced 4 027 and 25 403 DEGs in M. crystallinum roots, respectively. Among these DEGs, 832 and 131 DEGs were consistently upregulated and downregulated by both stresses, respectively. These genes were associated with multiple biological processes related to response to abiotic stresses. Alkaline stress upregulated genes encoding heat shock proteins and ethylene-related genes, but downregulated genes encoding glutathione S-transferases. Also, genes that encode phosphoenolpyruvate carboxylases, phosphoenolpyruvate carboxylase kinase 1, and malate dehydrogenases related to malate accumulation were upregulated by alkalinity. This study indicated that alkaline stress affected the genes related to stress responses, metabolism, and malate accumulation in the roots of M. crystallinum. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the protective effect of polyphenol extract from Highland barley (HBPE) on cisplatin (CDDP)-induced oxidative damage and mitochondrial damage in rat kidney. The experimental rats were divided into control group, CDDP group, HBPE (600 mg/kg) group, CDDP+HBPE (150 mg/kg) group, CDDP+HBPE (300 mg/kg) group and CDDP+HBPE (600 mg/kg) group. Rats in each group were intragastrically fed with normal saline and corresponding dose of HBPE for 21 d. On the 16th day, CDDP group and CDDP+HBPE group were injected intraperitoneally with CDDP (7.5 mg/kg), and the other groups were injected with the same amount of normal saline. On the 22nd day, the rats were killed and blood samples were taken to detect the contents of blood urea nitrogen (BUN) and creatinine (CrE) in serum, and calculate the kidney index. The kidney samples were used for the measurement of malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), lactate dehydrogenase (LDH), malate dehydrogenase (MDH), hexokinase (HK), and processed for histopathological examinations. The results showed that HBPE improved the abnormalities of serum CrE, BUN, antioxidant and carbohydrate metabolic enzymes in kidney induced by CDDP. HBPE can also reduce the degeneration of renal tubules and glomerular atrophy. Therefore, HBPE has a significant protective effect on oxidative stress injury and mitochondrial damage induced by CDDP in rats. [ABSTRACT FROM AUTHOR]

The article presents the results of studying the enzymatic activity of malate dehydrogenase in amaranth varieties and breeding populations of different ripeness groups and vegetation lengths. The studied amaranth species were A. caudatus L., A. mantegazzianus Passer., A. hybridus L., and A. hypochondriacus L. It was found that the enzymatic activity of malate dehydrogenase ensured the glyoxylate cycle functioning. The malate dehydrogenase activity varied depending on the enzyme accumulation during the initial stages of amaranth plant development. Isoenzyme analysis revealed two isoforms of malate dehydrogenase. It was noted that, in the studied amaranth species, the F-band was intrinsic to the early-ripening forms, while the late-ripening carried the S-band. In addition, we detected the malate dehydrogenase polymorphism and differences in the enzymatic activity and demonstrated that it was possible to use them as a biochemical marker in breeding. [ABSTRACT FROM AUTHOR]

The tricarboxylic acid (TCA) cycle is a central route for generating cellular energy and precursors for biosynthetic pathways. Emerging evidences have shown that the aberrations of metabolic enzymes which affect the integrity of TCA cycle are implicated in various tumour pathological processes. Interestingly, several TCA enzymes exhibit the characteristics of RNA binding properties, and their long non-coding RNA (lncRNA) partners play critical regulatory roles in regulating the function of TCA cycle and tumour progression. In this review, we will discuss the functional roles of RNA binding proteins and their lncRNA partners in TCA cycle, with emphasis placed on the cancer progression. A further understanding of RNA binding proteins and their lncRNA partners in TCA cycle, as well as their molecular mechanisms in oncogenesis, will aid in developing novel layers of metabolic targets for cancer therapy in the near future. Abbreviations: CS: citrate synthase. AH: aconitase, including ACO1, and ACO2. IDH: isocitrate dehydrogenase, including IDH1, IDH2, and IDH3. KGDHC: α-ketoglutarate dehydrogenase complex, including OGDH, DLD, and DLST. SCS: succinyl-CoA synthase, including SUCLG1, SUCLG2, and SUCLA2. SDH: succinate dehydrogenase, including SDHA, SDHB, SDHC, and SDHD. FH: fumarate hydratase. MDH: malate dehydrogenase, including MDH1 and MDH2. PC: pyruvate carboxylase. ACLY: ATP Citrate Lyase. NIT: nitrilase. GAD: glutamate decarboxylase. ABAT: 4-aminobutyrate aminotransferase. ALDH5A1: aldehyde dehydrogenase 5 family member A1. ASS: argininosuccinate synthase. ASL: adenylosuccinate synthase. DDO: D-aspartate oxidase. GOT: glutamic-oxaloacetic transaminase. GLUD: glutamate dehydrogenase. HK: hexokinase. PK: pyruvate kinase. LDH: lactate dehydrogenase. PDK: pyruvate dehydrogenase kinase. PDH: pyruvate dehydrogenase complex. PHD: prolyl hydroxylase domain protein. [ABSTRACT FROM AUTHOR]

A photoelectrochemical biosensor for malate was developed using an indium tin oxide (ITO) layer deposited on a poly(ethylene terephthalate) plastic sheet as a transparent electrode material for the immobilization of malate dehydrogenase together with CdTe quantum dots. Different approaches were compared for the construction of the bioactive layer; the highest response was achieved by depositing malate dehydrogenase together with CdTe nanoparticles and covering it with a Nafion/water (1:1) mixture. The amperometric signal of this biosensor was recorded during irradiation with a near-UV LED in the flow-through mode. The limit of detection was 0.28 mmol/L, which is adequate for analyzing malic acid levels in drinks such as white wines and fruit juices. The results confirm that the cheap ITO layer deposited on the plastic sheet after cutting into rectangular electrodes allows for the economic production of photoelectrochemical (bio)sensors. The combination of NAD+-dependent malate dehydrogenase with quantum dots was also compatible with such an ITO surface.

Malate dehydrogenase (MDH; EC 1.1.1.37) plays a vital role in plant growth and development as well as abiotic stress responses, and it is widely present in plants. However, the MDH family genes have not been explored in sweet potato. In this study, nine, ten, and ten MDH genes in sweet potato (Ipomoea batatas) and its two diploid wild relatives, Ipomoea trifida and Ipomoea triloba, respectively, were identified. These MDH genes were unevenly distributed on seven different chromosomes among the three species. The gene duplications and nucleotide substitution analysis (Ka/Ks) revealed that the MDH genes went through segmental duplications during their evolution under purifying selection. A phylogenetic and conserved structure divided these MDH genes into five subgroups. An expression analysis indicated that the MDH genes were omni-presently expressed in distinct tissues and responded to various abiotic stresses. A transcription factor prediction analysis proved that Dof, MADS-box, and MYB were the main transcription factors of sweet potato MDH genes. These findings provide molecular features of the MDH family in sweet potato and its two diploid wild relatives, which further supports functional characterizations.

Salinity is an important environmental factor influencing crop growth and yield. Malate dehydrogenase (MDH) catalyses the reversible conversion of oxaloacetate (OAA) to malate. While many MDHs have been identified in various plants, the biochemical function of MDH in rice remains uncharacterised, and its role in growth and salt stress response is largely unexplored. In this study, the biochemical function of OsMDH12 was determined, revealing its involvement in regulating tiller number and salt tolerance in rice. OsMDH12 localises in the peroxisome and is expressed across various organs. In vitro analysis confirmed that OsMDH12 converts OAA to malate. Seedlings of OsMDH12-overexpressing (OE) plants had shorter shoot lengths and lower fresh weights than wild-type (WT) plants, while osmdh12 mutants displayed the opposite. At maturity, OsMDH12-OE plants had fewer tillers than WT, whereas osmdh12 mutants had more, suggesting OsMDH12’s role in tiller number regulation. Moreover, OsMDH12-OE plants were sensitive to salt stress, but osmdh12 mutants showed enhanced salt tolerance. The Na+/K+ content ratio increased in OsMDH12-OE plants and decreased in osmdh12 mutants, suggesting that OsMDH12 might negatively affect salt tolerance through influencing the Na+/K+ balance. These findings hint at OsMDH12’s potential as a genetic tool to enhance rice growth and salt tolerance.

Malate dismutation involves a reductive branch from malate to succinate, and an oxidative branch that converts malate to acetate (Fig. The alternative ETC that functions with rhodoquinone consumes fumarate, which as far as it is known from well-studied organisms, derives from malate dismutation, and requires PEP carboxykinase and malate dehydrogenase to sustain malate synthesis. Cytosolic malate dehydrogenase, on the other hand, generates oxaloacetate from malate. The metabolomic analysis presented by Vora et al. indicated an increase in metabolites shared by both gluconeogenesis and malate dismutation pathways, such as malate and fumarate. [Extracted from the article]

Mutations in IDH1 (isocitrate dehydrogenases) such as R132H/Q/C, are frequently found in intrahepatic cholangiocarcinoma (IHCC). Mutant IDH1 proteins obtain an abnormal activity converting α-ketoglutarate (αKG) to 2-hydroxyglutarate (2-HG), inhibiting the activity of multiple αKG-dependent dioxygenases, leading to metabolism disorder. Here, we depict a molecular network leading by mutant IDH1, that regulates hepatic lipid embolism using mouse model (KI) with IDH1 R132Q specifically knocked in liver. KI mice appear small and have notably reduced hepatic TG and FFA levels. Technically, mutant IDH1-mediated 2-HG can stabilize PTEN mRNA level probably depending on miR-32, activate Akt-SEBP1c signaling, leading to lipogenesis defect. Our study identifies a new role of oncometabolite 2-HG in inhibiting hepatic lipid metabolism. • IDH1 R132Q knock-in mice show hepatic lipogenesis defect. • Mutant IDH1 curbs hepatic lipogenesis via PTEN-dependent pathway. • 2-HG elevates PTEN mRNA level probably relying on miR-32. [ABSTRACT FROM AUTHOR]

Background: To identify potential targets related to nicotinamide adenine dinucleotide (NAD+) metabolism in gliomas, we used RNA immunoprecipitation to identify a novel long noncoding RNA renamed malate dehydrogenase degradation helper (MDHDH) (NONCODE annotation ID: NONHSAT138800.2, NCBI Reference Sequence: NR_028345), which bound to MDH2 (malate dehydrogenase 2), that is downregulated in glioblastoma multiforme (GBM) and associated with metabolic regulation. However, its underlying mechanisms in the progression of GBM have not been well studied. Methods: To investigate the clinical significance of MDHDH, we analyzed its expression levels in publicly available datasets and collected clinical samples from Shandong Provincial Hospital, affiliated with Shandong University. Functional assays, including FISH/CISH, CCK8, EdU, wound healing, and transwell assays, were used to determine the cellular/subcellular localization, tissue expression profile and anti-oncogenic role of MDHDH. Furthermore, RNA pulldown, mass spectrometry RNA immunoprecipitation, coimmunoprecipitation, JC-1 probe, and cell energy-production assays were used to determine the mechanisms of MDHDH in the development of GBM. Animal experiments were conducted to determine the antitumorigenic role of MDHDH in GBM in vivo. Results: In public datasets, MDHDH expression was significantly downregulated in GBM and LGG compared with GTEx normal brain tissues. The results of the tissue microarray showed that the MDHDH expression level negatively correlated with the tumor grade. Altered MDHDH expression led to significant changes in the proliferation, migration and invasion of GBM cells both in vitro and in vivo. Mechanistically, we found that MDHDH directly bound to MDH2 and PSMA1 (20S proteasomal core subunit alpha-type 1) as a molecular scaffold and accelerated the degradation of MDH2 by promoting the binding of ubiquitinated MDH2 to the proteasome. The degradation of MDH2 subsequently led to changes in the mitochondrial membrane potential and NAD+/NADH ratio, which impeded glycolysis in glioma cells. Conclusions: In conclusion, this study broadened our understanding of the functions of lncRNAs in GBM. We demonstrated that the tumor suppressor MDHDH might act as a clinical biomarker and that the overexpression of MDHDH might be a novel synergistic strategy for enhancing metabolism-based, epigenetic-based, and autophagy regulation-based therapies with clinical benefits for glioblastoma multiforme patients. [ABSTRACT FROM AUTHOR]

Dormancy is an adaptation mechanism of plants to environmental stress. Myricaria laxiflora undergoes a long period of flooding stress every year. In order to determine whether this species escapes flooding stress through dormancy, young branches and leaves were collected at different time points before the onset of flooding, and changes in the content/activity of hormones/enzymes that are closely involved in plant growth were monitored. The inducing environmental factors of summer dormancy were identified. The branches and leaves of M. laxiflora showed the following trends as summer flooding approached: (1) gradual increase in the abscisic acid content; (2) gradual decrease in the gibberellin and cytokinin contents; and (3) a continuous decrease in the activities of malate dehydrogenase (MDH), ribulose diphosphate carboxylase (RuBisCo), and glycolate oxidase (GLO). Pearson correlation analysis revealed (1) daylight duration was highly correlated with the hormone content and enzyme activity; (2) the daily mean air temperature (DMAT) was significantly correlated with the cytokinin content. These findings suggest that daylight duration was the main environmental factor leading to changes in the phytohormone content and enzyme activity as well as leading to summer dormancy. M. laxiflora undergoes dormancy before the onset of summer flooding to escape summer flooding stress. Our data indicate that summer flooding does not impede the survival and growth of M. laxiflora. • The content of abscisic acid increased with the approach of summer flooding. • The content of cytokinin, gibberellin and enzymes decreased. • Change of daylight duration induced the variation of phytohormone and enzyme content. • M. laxiflora undergoes dormancy induced by daylight duration before summer flooding. [ABSTRACT FROM AUTHOR]

TATA box-binding protein-associated factor 12 (TAF12) has been identified as an oncogene in choroid plexus carcinoma, but its role in glioma is poorly understood because of a lack of previous studies. This study investigated the relationship of TAF12 expression with the clinicopathologic features of glioma cases, as well as its prognostic value and biological function, using large-scale databases and clinical samples. TAF12 mRNA expression and clinicopathologic characteristics of glioma cases were assessed in three public databases, and bioinformatics analyses were conducted to explore the prognostic value and biological functions of TAF12 in glioma. High TAF12 expression was commonly associated with reduced survival time and poor clinical indexes, including higher World Health Organization grade, wild-type isocitrate dehydrogenase 1 expression, and 1p19q non-codeletion status (p < 0.0001). Multivariate Cox regression analysis showed that high TAF12 expression was an independent poor prognostic factor for glioma patients (hazard ratio = 1.41, 95% confidence interval, 1.18–1.68, p < 0.001). Functional enrichment analysis revealed involvement of TAF12 in immune and inflammatory responses in glioma. Also, expression of several immune checkpoint molecules was significantly higher in samples with high TAF12 expression. TAF12 is a potential independent prognostic factor for glioma, and these findings provide a foundation for further investigation of the potential role of TAF12 in immunotherapy. [ABSTRACT FROM AUTHOR]

The article probes the origin of tetraploid Tomopterna tandyi and tests the hypothesis that T. tandyi is an allotetraploid species based on the revised taxonomy and chromosomes in the African frog genus Tomopterna (Pyxicephalidae). The summary distinguished tetraploid Tomoptera from diploids by counting the chromosomes and analyzed rRNA sequences for all the Tomoptera species. It determined haplotype networks for gene fragments, divergence ages, isozymes and Tomoptera advertisement calls.