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The brain's substantial metabolic requirements, consuming a substantial fraction of the body's total energy despite its relatively small mass, necessitate sophisticated metabolic mechanisms for efficient energy distribution and utilization. The astrocyte-neuron lactate shuttle (ANLS) hypothesis has emerged as a fundamental framework explaining the metabolic cooperation between astrocytes and neurons, whereby astrocyte-derived lactate serves as a crucial energy substrate for neurons. This review synthesizes current understanding of brain energy metabolism, focusing on the dual roles of lactate as both an energy substrate and a signaling molecule. We examine the molecular underpinnings of metabolic compartmentalization, particularly the differential expression of lactate dehydrogenase (LDH) isozymes between astrocytes and neurons, which facilitates directional lactate flux. Recent evidence has challenged aspects of the classical ANLS model, revealing greater metabolic flexibility in neurons than previously recognized, including substantial LDHA expression and direct glucose utilization capabilities. Our recent studies on LDHB-deficient neurons provide new insights into the compensatory mechanisms and limitations of neuronal lactate metabolism, suggesting a more nuanced understanding of the ANLS hypothesis. Furthermore, we discuss lactate's emerging role as a signaling molecule in synaptic plasticity, memory formation, and neuroprotection, particularly in ischemic conditions where elevated lactate levels correlate with enhanced neuronal survival through prostaglandin E2-mediated vasodilation. This comprehensive review integrates classical perspectives with recent advances, providing an updated framework for understanding brain lactate metabolism and its therapeutic implications in neurological disorders. [ABSTRACT FROM AUTHOR]

Escherichia coli small heat‐shock protein IbpB (MW: 16 KDa) has holding chaperone activity and is present in cells at 30 °C as two large oligomers of MW 2.0–3.0 MDa and 600–700 KDa. We report here about the presence of two additional oligomers of MW around 400 and 130 KDa in cells under heat‐stress at 50 °C. These two smaller oligomers possess the most chaperone activity, as observed from the extent of inhibition of inactivation and aggregation separately, of L‐Lactate dehydrogenase in the presence of the individual oligomers at 52 and 60 °C, respectively. It is suggested here that the two larger oligomers act as poorly active storage forms, which under heat stress dissociate partially into smaller oligomers with high holdase activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Schistosoma mansoni lactate dehydrogenase (LDH) is allosterically regulated by ATP and FBP. • The active site of LDH from S. mansoni closely resembles that of prokaryotic LDHs. • The inhibition of LDH by ATP benefits the free-living, glycogen-consuming stages. • In the presence of glucose, FBP levels increase, neutralizing the inhibition by ATP. • This effect of FBP prevents fatally high FBP levels after entering the final host. Lactate dehydrogenase (LDH) from Schistosoma mansoni has peculiar properties for a eukaryotic LDH. Schistosomal LDH (SmLDH) isolated from schistosomes, and the recombinantly expressed protein, are strongly inhibited by ATP, which is neutralized by fructose-1,6-bisphosphate (FBP). In the conserved FBP/anion binding site we identified two residues in SmLDH (Val187 and Tyr190) that differ from the conserved residues in LDHs of other eukaryotes, but are identical to conserved residues in FBP-sensitive prokaryotic LDHs. Three-dimensional (3D) models were generated to compare the structure of SmLDH with other LDHs. These models indicated that residues Val187, and especially Tyr190, play a crucial role in the interaction of FBP with the anion pocket of SmLDH. These 3D models of SmLDH are also consistent with a competitive model of SmLDH inhibition in which ATP (inhibitor) and FBP (activator) compete for binding in a well-defined anion pocket. The model of bound ATP predicts a distortion of the nearby key catalytic residue His195, resulting in enzyme inhibition. To investigate a possible physiological role of this allosteric regulation of LDH in schistosomes we made a kinetic model in which the allosteric regulation of the glycolytic enzymes can be varied. The model showed that inhibition of LDH by ATP prevents fermentation to lactate in the free-living stages in water and ensures complete oxidation via the Krebs cycle of the endogenous glycogen reserves. This mechanism of allosteric inhibition by ATP prevents the untimely depletion of these glycogen reserves, the only fuel of the free-living cercariae. Neutralization by FBP of this ATP inhibition of LDH prevents accumulation of glycolytic intermediates when S. mansoni schistosomula are confronted with the sudden large increase in glucose availability upon penetration of the final host. It appears that the LDH of S. mansoni is special and well suited to deal with the variations in glucose availability the parasite encounters during its life cycle. [ABSTRACT FROM AUTHOR]

]Objective]This work aims to solve the problem that the light purity of the final product D-lactic acid is reduced while using cheap raw materials(containing a small amount of L-lactic acid)such as agricultural rough processing or waste in the industrial fermentation production of D-lactic acid.]Method]The expressing plasmids of L-lactate dehydrogenase gene lldD, pUC19-PLD(PpflBp6), pUC19-NLD(PnirB)and pUC19-PNLD(PpflBp6-PnirB)with different promoters, were constructed and transformed into Escherichia coli D-lactic acid engineering strain HBUT-D, and strain HBUT-D3, HBUT-D5 and HBUT-D7 was acquired respectively. Through LldD enzymatic activity test and TOPSIS multivariate evaluation on NBS fermentative experiments(supplemented with 1 g/L L-lactic acid), one strain was screened by its capability for fast elimination of L-lactic and high fermentative efficiency of D-lactic acid, for following fermentative experiments with cheap raw materials.[Result]HBUT-D7 was evaluated as the optimal strain based on the LldD specific enzyme activity of 64 U/g, L-lactate consumption rate of 34 mg/(L·h), and D-lactic acid productivity of 4.09 g/(L·h). When fermented with corn syrup, the L-lactic acid consumption rates of HBUT-D and HBUT-D7 were 10.41 mg/(L·h)and 34.75 mg/(L·h), respectively. The productivities of D-lactic acid were 4.24 g/(L·h)and 3.87 g/(L·h), respectively. The optical purities of D-lactic acid were 99.07% and 99.92%, respectively. When fermented with molasses, the L-lactic acid consumption rates of HBUT-D and HBUT-D7 were 6.87 mg/(L·h)and 17.18 mg/(L·h), respectively. The productivities of D-lactic acid were 1.93 g/(L·h)and 1.88 g/(L·h), respectively. The optical purities of D-lactic acid were 99.22% and 99.99%, respectively.]Conclusion]The expressing plasmid of the anaerobic inducible promoter may increase the L-lactate dehydrogenase enzyme activity in strain HBUT-D7, thus it can eliminate the L-lactic acid to increase the optical purity of D-lactic acid while using cheap raw materials for fermentation. [ABSTRACT FROM AUTHOR]

Background and Objectives The storage time of platelet concentrate is limited to 3-5 days due to various factors, including bacterial contamination and platelet storage lesions. Antioxidant agents have been found to significantly improve the survival and function of platelets. The purpose of this study was to investigate the effect of the antioxidant compounds L-carnitine, Resveratrol, and Vitamin C on platelet oxidative stress during storage. Materials and Methods This experimental study utilized six platelet concentrate bags to evaluate the antioxidant effect of L-carnitine, Resveratrol, and Vitamin C at concentrations of 50 and 100 mM. The effects of these antioxidants on malondialdehyde (MDA) levels, lactate dehydrogenase (LDH) enzyme activity, H2O2, and pH levels were measured on days 0, 3, and 5 of platelet storage. The data was analyzed using GraphPad Prism version 8 software and one-way ANOVA tests. Results The concentration of 100 mM antioxidant compounds had a stronger protective effect compared to 50 mM. These effects were significant on the fifth day of platelet storage. The impact of these antioxidants resulted in improving platelet quality, including a decrease in MDA levels, and LDH activity. Conclusions The results showed that the antioxidant compounds can affect oxidative conditions created during five days of storage and reduce platelet destruction during this time through a specific biochemical mechanism. [ABSTRACT FROM AUTHOR]

Aim: Life-threatening complications such as intra-device thrombus, infection, bleeding, kidney and liver failure are frequently encountered due to the use of left ventricular assist devices (LVADs). We aimed to determine the incidence of hemolysis in patients implanted with LVAD, the mechanical complications detected in patients with hemolysis, and whether hemolysis can be used as a predictor of complications. Material and Methods: In this single-center, retrospective clinical research study, we evaluated 40 patients with HeartWare (HeartWare International, Inc., MA, USA) LVAD implants to assess the incidence of hemolysis and its association with mechanical complications. Hemolysis parameters, including lactate dehydrogenase (LDH), bilirubin, serum-free hemoglobin (sfHg), corrected reticulocyte count (CRC), and haptoglobin, were measured in venous blood samples obtained from patients attending cardiovascular outpatient clinics. Patients were divided into two groups(group 1:without hemolysis, n=32; group 2: with hemolysis, n=8) based on the presence or absence of hemolysis, and demographic data, comorbidities, and laboratory results were compared. The time elapsed after implantation of the patients was min: 90 days, max: 3147 days. Results: Hemolysis was detected in 20% (8 out of 40) of the patients included in the study. Patients with hemolysis demonstrated higher CRC, LDH, and total bilirubin levels(p<0,005), and lower haptoglobin levels compared to those without hemolysis(p<0,001). Intra-device thrombus was detected as a mechanical complication in 2 patients with hemolysis. One patient died and the other was discharged after medical treatment. Conclusion: Our findings suggest that routine monitoring of hemolysis parameters in LVAD recipients may aid in the early detection of mechanical complications, such as pump thrombosis, before symptomatic manifestation, thus potentially reducing mortality. Assessing multiple parameters, including LDH, bilirubin, sfHg, CRC, and haptoglobin, is crucial for accurate hemolysis diagnosis and its association with mechanical complications. It should be supported by large series of studies with longer and similar follow-up periods and a larger number of patients. [ABSTRACT FROM AUTHOR]

Aim: In this study, we aimed to explore whether the Aronia melanocarpa (chokeberry) extract pre-treatment protects primary mouse astrocytes in an in vitro model of Parkinson’s disease (PD) induced by the application of mitochondrial toxin 6-hydroxydopamine (OHDA) and if this effect was related to its antioxidant properties. Material and methods: Experiments were performed on primary mouse astrocytes that were exposed for 24 h to different concentrations of chokeberry extract (10, 50 or 100 μg/mL). OHDA was added to the cell culture medium for the next 72 h. Cell culture media were prepared for the lactate dehydrogenase (LDH) cell cytotoxicity assay and the cell lysates for the western blot analyses. Results: We determined that the pre-treatment of astrocytes with different concentrations of chokeberry extract alone does not significantly affect the LDH activity in the cell media samples. Application of OHDA, however, significantly increased the LDH activity while the pre- treatment of cells with chokeberry extract in concentrations of 50 and 100 μg/mL decreased the intensity of cell damage. Neither OHDA application, nor aronia pre-treatment affected the expression level of antioxidant enzyme superoxide dismutase 1, and the OHDA-induced decrease in glutathione peroxidase 1 protein expression remained unchanged by the tested antioxidant application. Conclusions: This study points to possible protective effects of chokeberry extract in an in vitro model of PD. The exact mechanism of the protective effect is still unclear and could be the subject of further research. [ABSTRACT FROM AUTHOR]

Lactate/malate dehydrogenases (Ldh/Maldh) are ubiquitous enzymes involved in the central metabolic pathway of plants and animals. The role of malate dehydrogenases in the plant system is very well documented. However, the role of its homolog L-lactate dehydrogenases still remains elusive. Though its occurrence is experimentally proven in a few plant species, not much is known about its role in rice. Therefore, a comprehensive genome-wide in silico investigation was carried out to identify all Ldh genes in model plants, rice and Arabidopsis, which revealed Ldh to be a multigene family encoding multiple proteins. Publicly available data suggest its role in a wide range of abiotic stresses such as anoxia, salinity, heat, submergence, cold and heavy metal stress, as also confirmed by our qRT-PCR analysis, especially in salinity and heavy metal mediated stresses. A detailed protein modelling and docking analysis using Schrodinger Suite reveals the presence of three putatively functional L-lactate dehydrogenases in rice, namely OsLdh3, OsLdh7 and OsLdh9. The analysis also highlights the important role of Ser-219, Gly-220 and His-251 in the active site geometry of OsLdh3, OsLdh7 and OsLdh9, respectively. In fact, these three genes have also been found to be highly upregulated under salinity, hypoxia and heavy metal mediated stresses in rice. [ABSTRACT FROM AUTHOR]

2-Keto-3-deoxy- d-gluconate (KDG) is an important intermediate found in various sugars, sugar acids and polysaccharide catabolic pathways. Here, we report that a functionally uncharacterized type-2 malate/l-lactate dehydrogenase family protein (TTHB078) from Thermus thermophilus HB8 catalyzes a novel reaction, NAD(P)H-dependent reductase activity on KDG. This enzyme, designated KdgG, utilizes both NADH and NADPH as electron donors, but higher activity was observed with NADH. Analysis of the reaction product revealed that KdgG catalyzes reversible reduction of KDG to form 3-deoxy-d-mannonate. Molecular phylogenetic analysis indicated that KdgG and its homologs distributed in the genus Thermus form a novel clade among type-2 malate/l-lactate dehydrogenase family proteins. [ABSTRACT FROM AUTHOR]

As a solid tumor with high glycolytic activity, hepatocellular carcinoma (HCC) produces excess lactic acid and increases extracellular acidity, thus forming a unique immunosuppressive microenvironment. L-lactate dehydrogenase (LDH) and monocarboxylate transporters (MCTs) play a very important role in glycolysis. LDH is the key enzyme for lactic acid (LA) production, and MCT is responsible for the cellular import and export of LA. The synergistic effect of the two promotes the formation of an extracellular acidic microenvironment. In the acidic microenvironment of HCC, LA can not only promote the proliferation, survival, transport and angiogenesis of tumor cells but also have a strong impact on immune cells, ultimately leading to an inhibitory immune microenvironment. This article reviews the role of LA in HCC, especially its effect on immune cells, summarizes the progress of LDH and MCT-related drugs, and highlights the potential of immunotherapy targeting lactate combined with HCC. [Display omitted] [ABSTRACT FROM AUTHOR]

Aim: The study aimed to describe clinical characteristics and outcomes of pregnant women with COVID‐19 undergoing cesarean section, and evaluated the association of blood values at admission with severe COVID‐19 disease in this group of patients. Method: We retrospectively analyzed the clinical data of 110 patients infected with COVID‐19 who underwent cesarean section at Adana City Education and Research Hospital in Turkey. The COVID‐19 severity of the patients was classified as either severe or nonsevere disease according to World Health Organization of COVID‐19 clinical management guidance. We compared blood values, clinical characteristics, and outcomes between severe and nonsevere patients. Receiver operating characteristics (ROC) curves analyses and area under the ROC curve (AUC) value was calculated to evaluate the predictive value of blood parameters on the COVID‐19 severity. Results: Of the 110 women, 12 were severe cases. Severe patients had higher ferritin, neutrophil‐to‐lymphocyte ratio (NLR), lactate dehydrogenase (LDH), alanine transaminase (ALT), aspartate transaminase (AST), and procalcitonin levels on admission (p < 0.05). The ROC analysis demonstrated AUC of NLR, LDH, AST, ALT, ferritin, and procalcitonin was 0.757, 0.856, 0.840, 0.771, 0.821, and 0.698, respectively. The LDH had a maximum specificity (90.8%), with the cutoff value of 365. The O‐blood group was more likely to have severe illness than the non‐O‐blood group (relative risk: 3.6; 95% confidence interval; 1.2–10.4). Conclusion: This study shows that LDH values at admission are an early and powerful predictor of severe infection for pregnant women with COVID‐19 who will undergo a cesarean section. [ABSTRACT FROM AUTHOR]

Staphylococcus xylosus is a gram-positive bacterium that has attracted much attention due to its increasing clinical appearance, frequently associated with serious multidrug resistance cases. L-lactate dehydrogenase (LDH) has been related to drug resistance in several bacterial species. However, the mechanism of multidrug resistance in S. xylosus remains unclear as well as the involvement of LDH in such resistance. To explore the relationship between multidrug resistance and LDH in S. xylosus, we used tylosin-resistant S. xylosus as the parent strain to construct ldh knockout and complemented strains. Then, we tested their resistance to macrolides, lincosamides, tetracyclines, and aminoglycosides. In addition, the enzyme activity, metabolite content, and transcriptional level of key genes involved in the TCA cycle and thioredoxin system were determined to clarify the mechanism of resistance. We observed that the resistance to multiple antibiotics increased significantly after ldh knockout, especially that to lincomycin, whereas antibiotic sensitivity was partially restored in the complemented strain. The levels of pyruvate, nicotinamide adenine dinucleotide, and reactive oxygen species decreased significantly upon ldh knockout, and the activity of isocitrate dehydrogenase and malate dehydrogenase decreased. These results indicate that the lack of LDH promotes multidrug resistance in S. xylosus by inhibiting the TCA cycle and regulating the thioredoxin system. [ABSTRACT FROM AUTHOR]

The present study aims to investigate the impact of hydrogen-rich water on the lactic acid level in metformin-treated diabetic rats under hypoxia. Thirty Sprague--Dawley rats were randomly divided into five groups, including normal diet group, and diabetes model (DM) group, DM + metformin treatment DMM) group, DMM + hypoxia treatment (DMMH) group and DMMH + hydrogenrich water (DMMHR) group. We found that the levels of lactic acid, pyruvate and lactate dehydrogenase were significantly lower in the blood of DMMHR group than DMMH group. Superoxide dismutase and glutathione levels in liver and heart were significantly higher in DMMH group after hydrogen-rich water treatment, while malondialdehyde and oxidized glutathione levels were decreased in DMMHR group when compared with DMMH group, which indicates that hydrogen-rich water could reduce oxidative stress. qPCR analysis demonstrated that that pro-apoptotic genes Bax/Caspase-3 were upregulated in DM group and metformin treatment suppressed their upregulation (DMM group). However, hypoxic condition reversed the effect of metformin on apoptotic gene expression, and hydrogen-rich water showed little effect on these genes under hypoxia. HE staining showed that hydrogen-rich water prevented myocardial fiber damages under hypoxia. In summary, we conclude that hydrogen-rich water could prevent lactate accumulation and reduce oxidant stress in diabetic rat model to prevent hypoxia-induced damages. It could be served as a potential agent for diabetes patients with metformin treatment to prevent lactic acidosis and reduce myocardial damages under hypoxic conditions. [ABSTRACT FROM AUTHOR]

L-lactate is an important metabolite, energy source, and signaling molecule in health and disease. In mammals, its transport across biological membranes is mediated by monocarboxylate transporters (MCTs) of the solute carrier 16 (SLC16) family. Malfunction, overexpression or absence of transporters of this family are associated with diseases such as cancer and type 2 diabetes. Moreover, lactate acts as a signaling molecule and virulence factor in certain bacterial infections. Here, we report the rational, structure-guided identification of potent, nanomolar affinity inhibitors acting on an L-lactate-specific SLC16 homologue from the bacterium Syntrophobacter fumaroxidans (SfMCT). High-resolution crystal structures of SfMCT with bound inhibitors uncovered their interaction mechanism on an atomic level and the role of water molecules in inhibitor binding. The presented systematic approach is a valuable procedure for the identification of L-lactate transport inhibitors. Furthermore, identified inhibitors represent potential tool compounds to interfere with monocarboxylate transport across biological membranes mediated by MCTs. The L-lactate-specific transporter SfMCT is a model SLC16 family homologue for the determination of inhibitors and potential drugs. Here, starting from a weakly-binding non-transported ligand, nanomolar affinity inhibitors of SfMCT are developed and crystal structures of the transporter-ligand complexes are presented unveiling interactions at the atomic level. [ABSTRACT FROM AUTHOR]

l -lactate dehydrogenases (LDHs) has been widely studied for their ability to reduce 2-keto acids for the production of 2-hydroxy acids, whereby 2-hydroxybutyric acids (2-HBA) is among the most important fundamental building blocks for synthesizing pharmaceuticals and biodegradable materials. However, LDHs usually show low activity towards 2-keto acids with longer side chain such as 2-oxobutyric acid (2-OBA). Here rational engineering of the Plasmodium falciparum LDH loop with residue involved in the catalytic proton transfer was initially studied. By combining homology alignment and structure-based design approach, we found that changing the charge characteristics or hydrogen bond network interactions of this loop could improve enzymatic catalytic activities and stabilities towards 2-OBA. Compared with wild type, variant N197D ldh showed 1.15 times higher activity and 2.73 times higher K cat / Km. The half-life of variant N197D ldh at 40 °C increased to 77.9 h compared with 50.4 h of wild type. Furthermore, asymmetric synthesis of (S)-2-HBA with coenzyme regeneration revealed 95.8 g/L production titer within 12 h for variant N197D ldh , 2.05 times higher than using wild type. Our study indicated the importance of loop with residues involved in the catalytic proton transfer process, and the engineered LDH would be more suitable for (S)-2-HBA production. [Display omitted] • Rational engineering the Pf LDH loop with residue His195 involved in the catalytic proton transfer was initially studied. • Variant N197D ldh showed improved activity and stability towards 2-Oxobutyric acid was obtained by this strategy. • Compared with wild type, variant N197D ldh showed 1.15 times higher activities and 2.73 times higher k cat / K m. • Variant N197D ldh showed 95.8 g/L (S)-2-hydroxybutyrate production within 12 h, 2.05 times higher than that of wild type. [ABSTRACT FROM AUTHOR]

Lactate are proved to be attractive electron donor for the production of n-caproic acid (CA) that is a high value-added fuel precursor and chemical feedstock, but little is known about molecular mechanism of lactate transformation. In the present study, the gene for L-lactate dehydrogenase (LDH, EC.1.1.1.27) from a Ruminococcaceae strain CPB6 was cloned and expressed in Escherichia coli BL21 (DE3) with plasmid pET28a. The recombinant LDH exhibited molecular weight of 36–38 kDa in SDS-PAGE. The purified LDH was found to have the maximal oxidation activity of 29.6 U/mg from lactate to pyruvate at pH 6.5, and the maximal reduction activity of 10.4 U/mg from pyruvate to lactate at pH 8.5, respectively. Strikingly, its oxidative activity predominates over reductive activity, leading to a 17-fold increase for the utilization of lactate in E. coli/pET28a-LDH than E. coli/pET28a. The CPB6 LDH gene encodes a 315 amino acid protein sharing 42.19% similarity with Clostridium beijerinckii LDH, and lower similarity with LDHs of other organisms. Significant difference were observed between the CPB6 LDH and C. beijerinckii and C. acetobutylicum LDH in the predicted tertiary structure and active center. Further, X-ray crystal structure analysis need to be performed to verify the specific active center of the CPB6 LDH and its role in the conversion of lactate into CA. [ABSTRACT FROM AUTHOR]

Ravulizumab, a novel long‐acting complement component 5 (C5) inhibitor administered every 8 weeks (q8w), was non‐inferior to eculizumab for all efficacy outcomes in two randomised, open‐label, phase 3 trials in C5 inhibitor‐naïve (Study 301) and eculizumab‐experienced (Study 302) adult patients with paroxysmal nocturnal haemoglobinuria (PNH). This pre‐specified analysis characterised ravulizumab pharmacokinetics (PK), pharmacodynamics (PD; free C5 levels), and PD differences between medications (Study 301, n = 246; Study 302, n = 195). Ravulizumab PK parameters were determined using non‐compartmental analysis. Serum free C5 was quantified with a Gyros‐based fluorescence assay (ravulizumab) and an electrochemiluminescence ligand‐binding assay (eculizumab). Ravulizumab PK parameters were numerically comparable in both studies; the median time to maximum concentrations ranged from 2·3 to 2·8 and 2·3 to 2·6 h in studies 301 and 302, respectively. Ravulizumab steady‐state serum concentrations were achieved immediately after the first dose and sustained throughout treatment. For ravulizumab, the mean (SD) post hoc terminal elimination half‐life was 49·7 (8·9) days. Serum free C5 concentrations <0·5 µg/ml were achieved after the first ravulizumab dose and sustained throughout treatment in both studies. In a minority of patients, free C5 concentrations <0·5 µg/ml were not consistently achieved with eculizumab in either study. Ravulizumab q8w was more consistent in providing immediate, complete, sustained C5 inhibition than eculizumab every‐2‐weeks in patients with PNH. [ABSTRACT FROM AUTHOR]

Unstructured biological macromolecules have attracted attention as protein aggregation inhibitors in living cells. Some are characterized by their free structural configuration, highly charged, and water-soluble. However, the importance of these properties in inhibiting protein aggregation remains unclear. In this study, we investigated the effect of charged poly (amino acids), which mimic these properties, on aggregation of l -lactate dehydrogenase (LDH) and compared their effects to monomeric amino acids and folded proteins. LDH was stable and active at a neutral pH (~7) but formed inactive aggregates at acidic pH (< 6). Adding cationic polyelectrolytes of poly- l -lysine and poly- l -arginine suppressed the acid-induced aggregation and inactivation of LDH under acidic pH values. Adding monomeric amino acids and cationic folded proteins also prevented LDH aggregation but with lower efficacy than cationic polyelectrolytes. These results indicate that unstructured polyelectrolytes effectively stabilize unstable enzymes because they interact flexibly and multivalently with them. Our findings provide a simple method for stabilizing enzymes under unstable conditions. • Simple and versatile strategies for enzyme stabilization are required. • Cationic polyelectrolytes prevent aggregation of L-lactate dehydrogenase (LDH). • Cationic polyelectrolytes maintain LDH activity at acidic pH. • Cationic polyelectrolytes are effective at lower concentrations than other additives. [ABSTRACT FROM AUTHOR]

Lactate dehydrogenase (LDH) widely exists in organisms, which catalyzes the interconversion of pyruvate into lactate with concomitant interconversion of NADH and NAD+. In this study, two L-type lactate dehydrogenase genes FgLDHL1 and FgLDHL2 were characterized in an ascomycete fungus Fusarium graminearum, a causal agent of wheat head blight. Both the single-gene deletion mutants of FgLDHL1 or FgLDHL2 exhibited phenotypic defects in vegetative growth, sporulation, spore germination, L-lactate biosynthesis and activity. Additionally, the two L-lactate dehydrogenases were involved in the utilization of carbon sources and maintenance of redox homeostasis during spore germination. Pathogenicity assays showed that ΔFgLDHL1 exhibits reduced virulence on wheat spikelets and on corn stigmas, suggesting that it was indirectly correlated with a reduced level of deoxynivalenol accumulation. These results indicate that FgLDHL1 and FgLDHL2 play multiple roles in the developmental processes and pathogenesis in F. graminearum, and help understand the functional diversity of D-/L-lactate dehydrogenase in phytopathogenic fungi. [ABSTRACT FROM AUTHOR]

Background: The clinical response to anti-programmed cell death 1 (PD-1) antibodies in patients with advanced gastric and gastroesophageal junction (GEJ) cancer in China has not been reported.Methods: This study evaluated the efficacy and safety of SHR-1210, an anti-PD-1 antibody, in patients with advanced gastric/GEJ cancer in a phase 1 trial. The associations between candidate biomarkers (programmed death ligand 1 [PD-L1] expression, mismatch repair status, tumor mutation load, and lactate dehydrogenase [LDH] levels) and the efficacy of SHR-1210 were also explored.Results: Thirty patients with recurrent or metastatic gastric/GEJ adenocarcinoma who were refractory or intolerant to previous chemotherapy were enrolled between June 2, 2016, and June 8, 2017. Seven patients (23.3%) demonstrated objective responses, including 1 complete response. The objective response rates for patients with PD-L1-positive and PD-L1-negative tumors were 23.1% (3 of 13) and 26.7% (4 of 15), respectively (P = 1.000). Two treatment-related grade 3 or higher adverse events were reported: one was grade 3 pruritus, and the other (3.3%) was grade 5 interstitial lung disease. All 20 patients tested for the mismatch repair status had mismatch repair-proficient tumors, and the response rate was 30.0% (95% confidence interval, 11.9%-54.3%). Patients with a higher mutation load (4 of 10) tended to have better responses than those with fewer mutations (2 of 10), but the difference was not significant (P = .628). Patients with a >10% relative increase from the baseline LDH level were more likely to experience disease progression (90% [9 of 10]) than patients with a ≤10% change (40% [8 of 20]; P = .017).Conclusions: Anti-PD-1 antibody SHR-1210 shows encouraging efficacy in patients with advanced gastric/GEJ cancer in China, including mismatch repair-proficient subgroups. [ABSTRACT FROM AUTHOR]

This study aimed to analyze the effects of laser irradiation on the membrane integrity and viability of stem cells from human exfoliated deciduous teeth (SHED) that were kept in serum starvation. Nutritional deficit was used to mimic the cellular stress conditions of SHED isolation for regenerative dental approaches, where laser therapy could be beneficial. SHED were cultured under serum starvation (MEMα + 1%FBS) for 1 or 24 h pre-irradiation (protocols A and B, respectively). Then, cells received low-level laser therapy (LLLT; 660 nm) at 2.5 J/cm2 (0.10 W; groups I and V), 5.0 J/cm2 (0.20 W; groups II and VI), 7.5 J/cm2 (0.30 W; groups III and VII), or remained non-irradiated (groups IV and VIII). During irradiation, cells were maintained in 1% FBS (groups I-IV) or 10% FBS (normal culture conditions; groups V-VIII). Membrane integrity was evaluated by quantifying lactate dehydrogenase (LDH) release (immediately after irradiation), and cell viability was assessed by the MTT assay (24, 48, and 72 h post-irradiation). Serum starvation did not alter LDH release by non-irradiated SHED, while LDH release decreased significantly in groups irradiated in 1% FBS (I and III), but not in groups irradiated in 10% FBS (V-VII), regardless the pre-irradiation conditions (protocols A/B). Cell viability was significantly higher 24 h after irradiation, in most protocol A groups. In contrast, cell viability remained mostly unaltered in protocol B groups. LLLT contributed to maintain membrane integrity in SHED subjected to nutritional deficit before and during irradiation with 0.10 or 0.30 W. Short serum starvation before irradiation improved SHED viability at 24 h post-irradiation. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • B. coagulans IPE22 had the ability to excrete amylase (29.47 mU/mg in DF). • One step open SLSF method was optimal for LA production by B. coagulans. • LA productivity was related to both LDH activity and glucose concentration. • Inedible cassava and sorghum flour were alternatives of refined starch. Abstract The aim of this study was to establish a simplified operational process for lactic acid (LA) production by Bacillus coagulans IPE22 from inedible starchy biomass with open fermentation method. First, 29.47 mU/mg specific amylase activity was detected in direct batch fermentation from soluble starch, but the activity of the produced amylase was too low for effective production of LA. Then seven batches from 72 g/L soluble starch were conducted without sterilization. It was found that one step simultaneous liquefaction, saccharification and fermentation (SLSF) with the addition of mesothermal α-amylase and glucoamylase was the optimal mode with LA concentration, yield and productivity of 68.72 g/L, 0.99 g/g and 1.72 g/L h respectively. Finally, inedible starchy biomass, cassava and sorghum flours, were proved to be alternatives to refined soluble starch. For the first time, one step open SLSF of inedible starchy biomass was reported for LA production by B. coagulans. [ABSTRACT FROM AUTHOR]

To improve the specific activity and catalytic efficiency of l - Lc LDH1, an NADH-dependent allosteric l -lactate dehydrogenase from L. casei , towards phenylpyruvic acid (PPA), its directed modification was conducted based on the semi-rational design. The three variant genes, Lcldh1 Q88R , Lcldh1 I229A and Lcldh1 T235G , were constructed by whole-plasmid PCR as designed theoretically, and expressed in E. coli BL21(DE3), respectively. The purified mutant, l - Lc LDH1 Q88R or l - Lc LDH1 I229A , displayed the specific activity of 451.5 or 512.4 U/mg towards PPA, by which the asymmetric reduction of PPA afforded l -phenyllactic acid (PLA) with an enantiomeric excess ( ee p ) more than 99%. Their catalytic efficiencies ( k cat / K m ) without d -fructose-1,6-diphosphate ( d -FDP) were 4.8- and 5.2-fold that of l - Lc LDH1. Additionally, the k cat / K m values of l - Lc LDH1 Q88R and l - Lc LDH1 I229A with d -FDP were 168.4- and 8.5-fold higher than those of the same enzymes without d -FDP, respectively. The analysis of catalytic mechanisms by molecular docking (MD) simulation indicated that substituting I229 in l - Lc LDH1 with Ala enlarges the space of substrate-binding pocket, and that the replacement of Q88 with Arg makes the inlet of pocket larger than that of l - Lc LDH1. [ABSTRACT FROM AUTHOR]

Danshensu (DSS), also known as 3,4-dihydroxyphenyllactate, is an herbal preparation with prominent pharmacological activities. It has lactic acid structure and may be obtained by reducing 3,4-dihydroxyphenylpyruvate with lactate dehydrogenase. We screened a coenzyme-aspecific L-lactate dehydrogenase (LF-L-LDH0845) from lactobacillus fermentum for the bioconversion of 3,4-dihydroxyphenylpyruvate to optically pure (ee ≥ 99.99%) L-DSS. LF-L-LDH0845 has an approximate molecular weight of 33.65 kDa, exhibits wide substrate scope for 2-keto-carboxylic acids. Values of Km, Kcat, and Kcat/Km for LF-L-LDH0845 with 3,4-dihydroxy-phenylpyruvate substrate were 11.37 mM, 0.2931 s −1 , and 0.0258 mM −1  s −1 , respectively. LF-L-LDH0845 was most active and stable at pH 6.0, the optimum temperature was 25 °C, stability decreased with increasing temperature, and activity was lost completely at 50 °C. K + stimulated while Fe 2+ and Cu 2+ inhibited the enzyme activity significantly. Glucose dehydrogenase gene was coexpressed with lf-l-ldh0845 in E. coli to regenerate cofactors by oxidising glucose, which efficiently reduced 3,4-dihydroxyphenylpyruvate to L-DSS with 95.45% isolation yield. [ABSTRACT FROM AUTHOR]

Autoimmune hepatitis is a chronic inflammatory disease in the liver with potential to the development of liver fibrosis. Recent evidences suggest that bone marrow derived mesenchymal stem cells (BMSCs) may exert its therapeutic activity through exosomes. Moreover, miR-223 is highly expressed in BMSCs and plays an important role in autoimmune diseases. Therefore, in this study, hepatoprotective role of BMSCs and miR-223 was investigated in both mice and hepatocytes. Liver antigen S100 was used to establish autoimmune hepatitis model in mice while LPS and ATP were used to establish cell injury model in hepatocyte. Before the experiments, BMSCs were infected with pre-miR-223 and transfected with miR-223 inhibitor respectively. Exosomes from bone marrow stem cells were isolated by ultracentrifugation. Liver injury was evaluated by serum levels of ALT and AST as well as liver histology. Inflammation and cell death were examined by inflammatory cytokines and lactase dehydrogenase respectively. Both BMSCs-exo and BMSCs-exo miR−223(+) significantly reversed either S100 or LPS/ATP induced injury in mice and hepatocytes. Meanwhile, the expressions of cytokines, NLRP3 and caspase-1 were also downregulated by BMSCs-exo and BMSCs-exo miR−223(+) at both protein and mRNA levels in mice and hepatocytes. Moreover, BMSCs-exo miR−223(−) reverses the effects of BMSCs-exo and BMSCs-exo miR−223(+) in mouse AIH and in hepatocytes. In conclusion, bone marrow stem cell derived exosomes can protect liver injury in an experimental model of autoimmune hepatitis and the mechanism could be related to exosomal miR-223 regulation of NLRP3 and caspase-1. [ABSTRACT FROM AUTHOR]

Background: L-Phenyllactic acid (L-PLA)--a valuable building block in the pharmaceutical and chemical industry--has recently emerged as an important monomer in the composition of the novel degradable biocompatible material of polyphenyllactic acid. However, both normally chemically synthesized and naturally occurring phenyllactic acid are racemic, and the product yields of reported L-PLA synthesis processes remain unsatisfactory. Methods: We developed a novel recombinant Escherichia coli strain, co-expressing L-lactate dehydrogenase (L-LDH) from Lactobacillus plantarum subsp. plantarum and glucose dehydrogenase (GDH) from Bacillus megaterium, to construct a recombinant oxidation/reduction cycle for whole-cell biotransformation of phenylpyruvic acid (PPA) into chiral L-PLA in an enantioselective and continuous manner. Results: During fed-batch bioconversion with intermittent PPA feeding, L-PLA yield reached 103.8 mM, with an excellent enantiomeric excess of 99.7%. The productivity of L-PLA was as high as 5.2 mM·h-1 per OD600 (optical density at 600 nm) of whole cells. These results demonstrate the efficient production of L-PLA by the one-pot biotransformation system. Therefore, this stereoselective biocatalytic process might be a promising alternative for L-PLA production. [ABSTRACT FROM AUTHOR]

Copper is essential for numerous physiological functions, and copper compounds may display therapeutic as well as cytotoxic effects. The MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide) assay is a standard test largely used in cytotoxicity studies. This report shows that low micromolar levels of copper compounds such as Cu(II)Urea 2 , Cu(II)Ser 2 and CuCl 2 can interfere with the MTT assay making improper the detection of formazan product of MTT reduction. Comparatively, the Neutral Red assay appears to be sensitive and showing no interference with these compounds. The lactate dehydrogenase alternative assay cannot be used because of inhibitory effect of these copper compounds on the enzyme activity. [ABSTRACT FROM AUTHOR]

BACKGROUND: The 2009 influenza pandemic renewed interest in timely identification of suspected influenza cases through routine laboratory studies, the most studied is lactic dehydrogenase (DHL). OBJECTIVE: To determine if patients with influenza A (H1N1) pneumonia present particular alterations inside routine laboratory studies, particularly in DHL levels and analyze the prognostic implication. MATERIAL AND METHOD: A case-control study of patients with confirmed diagnosis of influenza A (H1N1) pneumonia (case), and patients with bacterial pneumonia (control) treated from December 2013 to July 2014. RESULTS: Thirty-one cases were analyzed, 45% (n = 14) had a diagnosis of influenza A (H1N1) pneumonia, the remaining 55% (n = 17) was considered of bacterial etiology. The mean age was 38 (16-62) years old. The DHL level at diagnosis time was on average 578.77 IU/L (191-1096), higher in the group with influenza A (H1N1) pneumonia (573 IU/L vs 624.7 IU/L, p = 0.366). In the overall analysis, the levels of DHL > 350 IU/L at diagnosis time and at the end of treatment had a negative impact on mortality (OR: 84.0, 95%CI: 4.4754-1576.6044, and OR: 154.0, 8.6261-2749.3255). Overall survival was 18 days, lower in the A (H1N1) group (4 vs 25 days, p = 0.016). CONCLUSIONS: DHL > 350 IU/L can be considered a severity biomarker, also has a negative impact on the survival of patients with pneumonia without being able to discriminate the possible etiological agent. [ABSTRACT FROM AUTHOR]

L-Lactate (LL) is an essential cellular metabolite which can be used to generate energy. In addition, accumulating evidence suggests that LL is used for inter-cellular signalling. Some LL-sensitive receptors have been identified but we recently proposed that there may be yet another unknown G-protein coupled receptor (GPCR) sensitive to LL in the brain. Olfactory receptors (ORs) represent the largest family of GPCRs and some of them are expressed outside the olfactory system, including brain, making them interesting candidates for non-olfactory LL signalling. One of the “ectopically” expressed ORs, Olfr78 in mice (Olr59 in rats and OR51E2 in humans), reportedly can be activated by LL. This implies that both rodents and humans should be able to detect the LL odour. Surprisingly, this has never been demonstrated. Here we show that mice can detect the odour of LL in odour detection and habituation-dishabituation tasks, and discriminate it from peppermint and vanilla odours. Behaviour of the Olfr78 null mice and wildtype mice in odour detection task was not different, indicating that rodents are equipped with more than one LL-sensitive OR. Rats were also able to use the smell of LL as a cue in an odour-reward associative learning task. When presented to humans, more than 90% of participants detected a smell of LL in solution. Interestingly, LL was perceived differently than acetate or propionate—LL was preferentially reported as a pleasant sweet scent while acetate and propionate were perceived as repulsive sour/acid smells. Subjective perception of LL smell was different in men and women. Taken together, our data demonstrate that both rodents and humans are able to detect the odour of LL. Moreover, in mice, LL perception is not purely mediated by Olfr78. Discovery of further LL-sensitive OR might shed the light on their contribution to LL signalling in the body. [ABSTRACT FROM AUTHOR]

In human leukaemia, resistance to chemotherapy leads to treatment ineffectiveness or failure. Previous studies have indicated that cancers with increased levels of aerobic glycolysis are insensitive to numerous forms of chemotherapy and respond poorly to radiotherapy. Whether glycolysis serves a key role in drug resistance of leukaemia cells remains unclear. The present study systematically investigated aerobic glycolytic alterations and regulation in K562/adriamycin (ADM) multidrug-resistant (MDR) and ADM-sensitive K562 leukaemia cells in normoxia, and the association between drug resistance and improper glycometabolism. The cell proliferating activity was assessed with an MTT colorimetric assay, glycolysis, including glucose consumption, lactate export and key-enzyme activity was determined by corresponding commercial testing kits. The expression levels of hexokinase-II (HK-II), lactate dehydrogenase A (LDHA), glucose transporter-4 (GLUT-4), AKT, p-AKT473/308, mammalian target of rapamycin (mTOR), p-mTOR, c-Myc and hypoxia-inducible factor-1α (HIF-1α) were analyzed by western blot or reverse transcription-quantitative polymerase chain reaction (RT-qPCR). K562/ADM cells exhibited increased glucose consumption and lactate accumulation, increased lactate dehydrogenase, hexokinase and pyruvate kinase activities, and reduced phosphofructokinase activity. In addition, K562/ADM cells expressed significantly more HK-II and GLUT-4. Notably, inhibition of glycolysis effectively killed sensitive and resistant leukaemia cells and potently restored the sensitivity of MDR cells to the anticancer agent ADM. The AKT serine/threonine kinase (AKT)/mechanistic target of rapamycin (mTOR) signalling pathway, a crucial regulator of glycometabolic homeostasis, mediated over-activation and upregulation of c-Myc expression levels in K562/ADM cells, which directly stimulated glucose consumption and enhanced glycolysis. In conclusion, the present study demonstrated that MDR leukaemia cells exhibit increased aerobic glycolytic activity and that this may be responsible for resistance to chemotherapeutics in leukaemia MDR cells via activation of the AKT-mTOR-c-Myc signalling pathway. Therefore, inhibition of aerobic glycolysis may be a potential therapeutic strategy to efficiently treat multidrug resistance in relapsed or refractory leukaemia and cancers. [ABSTRACT FROM AUTHOR]

Assessment of blood L-lactate concentration (LAC) as point-of-care (POC) biomarkers is turning into a typical procedure for different diagnostic purposes in the food animal industry. The purpose of our study was to figure out whether blood LAC measured by a hand held lactate analyzer with different variables could be utilized to anticipate the event of bovine respiratory disease (BRD) in feedlot cattle. Moreover, assess the blood LAC stability over different time point in clinically healthy feedlot cattle. Blood sample was collected at entry during processing (n=104) and at initial diagnosis of BRD (n=24). In addition, clinically healthy pen matched controls calves (n=24) were sampled at the same time of pulling diseased calves for determination of blood LAC using a handheld portable lactate analyzer. In a separate study, selected clinically healthy calves (n=9) were sampled and blood LAC stability at the different time point (0, 30, 60, 90 and 120 minute) was assessed. Logistic regression model revealed blood LAC during initial processing was significantly associated with odds of becoming a BRD case in calves revealing lung score 2. Moreover, blood LAC was significantly different (P=0.02) between clinically healthy and those calves that developed BRD and was significantly correlated (P>0.01) within the different time points. Our results demonstrated that analyzing blood LAC at initial diagnosis of BRD together with other clinical variable might help in the treatment decision. Therefore, further investigation should be designed to correlate blood LAC measurements for prediction of BRD clinical outcomes. [ABSTRACT FROM AUTHOR]

A new L-lactate selective impedimetric biosensor based on a lactate dehydrogenase (LDH)/pyruvate oxidase (PyrOx) bioselective membrane is reported, fabricated using enzyme drop coating and cross-linking via glutaraldehyde vapours. The sensing strategy is based on the measurement of the change in impedance caused by the generation of charged ions (CH 3 COO − , H + and HCO 3 − ), from PyrOx catalysed pyruvate oxidation, the pyruvate resulting from L-lactate oxidation catalysed by LDH + nicotinamide adenine dinucleotide (NAD + ). The experimental conditions, pH and buffer concentration, were optimized for best biosensor response, and operational/storage stability and selectivity/specificity were investigated. The limit of detection for L-lactate, was 17 and 20 μM, considering changes in resistance and charge separation parameters at and close to the LDH-NAD + /PyrOx interface, respectively. The biosensor was successfully employed for the determination of L-lactate in yogurt samples. [ABSTRACT FROM AUTHOR]

This study investigated the effects of a type II arabinogalactan from Anoectochilus formosanus (AGAF) on natural killer (NK) cell-mediated cytotoxicity and the possible underlying mechanisms. This study reported that sustained exposure to AGAF increased NK-92MI cell-mediated cytotoxicity in a time- and concentration-dependent manner, as characterized according to the cellular lactic dehydrogenase leakage from K562 leukemia cells. Additionally, antibody neutralization studies have reported that interferon (IFN)-γ, but not perforin or tumor necrosis factor-α, released by NK-92MI NK cells is crucial in enhancing cytotoxicity through an autocrine loop. In this study, AGAF was further demonstrated to induce IFN-γ expression, increasing the susceptibility to NK-92MI cell-mediated cytotoxicity through the toll-like receptor (TLR)-2, TLR4, extracellular signal-regulated kinase, p38 mitogen-activated protein kinase, and nuclear factor-κB pathways. A pharmacological study revealed that Janus kinase 2/signal transducers and activators of the signal transducers and of transcription 3 signaling are involved in IFN-γ-induced NK cell-mediated cytotoxicity. [ABSTRACT FROM AUTHOR]

Blood gas disturbances, commonly resulting from dystocia, are associated with failed transfer of passive immunity, morbidity and mortality in newborn calves. Modified APGAR scores intended to identify compromised calves are not widely adopted due to lack of practicality and inconsistent associations with blood parameters. The objective of this study was to determine clinical indicators of acidemia in newborn beef calves. Blood parameters at 10 min and 24 h after birth were compared to at-birth clinical examination parameters and calving characteristics in 77 commercial beef calves. There were no associations between heart rate or respiratory rate and blood pH or blood L-lactate concentration (LAC; r  < 0.25); however, LAC was highly correlated with blood pH ( r , −0.86). Abnormal mucous membrane color (red, white or blue) was associated with increased LAC ( P  = 0.002) but not decreased blood pH ( P  = 0.07). Abnormal results for tests of muscle tonicity and reflexes, namely inability to completely withdraw the tongue when pinched and a weak suckle reflex, were associated with decreased blood pH and increased LAC ( P  <   0.05). Calves born to primiparous dams or from an assisted calving also had decreased blood pH and increased LAC ( P  <   0.05). Differences in blood pH between at-birth categories resolved for all parameters by 24 h after birth, except for tongue withdrawal ( P   =  0.04). In conclusion, traditional APGAR parameters, heart rate, respiratory rate and mucous membrane color were not useful for the identification of acidemic calves; however, tongue withdrawal, calving ease, and parity should be included in such an assessment. Utilizing hand-held LAC meters may be a practical method to quickly identify compromised calves with acidemia in a field setting. [ABSTRACT FROM AUTHOR]

A 66-year-old man developed a slowly enlarging, bilateral, painless, periorbital, and orbital swelling with ptosis, nonaxial proptosis, chemosis, exposure keratopathy, and decreased vision in both eyes. He had fever, night sweats, and weight loss (B-symptoms), along with lymphadenopathy and elevated serum lactate dehydrogenase, with no prior history of lymphoma. A transpalpebral incisional biopsy revealed a rare case of mantle-cell lymphoma of blastoid variant, stage IVB. The main immunophenotype characteristics were cyclin D1+, CD5+, CD10−, CD23−, Bcl-6−/+, and a high (up to 80%) Ki-67 proliferation index. Following an excellent response to the immune-chemotherapy treatment plan, all ocular adnexal lymphoma manifestations disappeared completely; however, 13 months after the initial presentation, there was a recurrence of the disease with rapid worsening and death. The blastoid variant of mantle cell lymphoma, a rare subtype of mantle-cell lymphoma, is a highly aggressive neoplasm, ultimately having a fatal outcome. As the initial manifestation of the disease, ocular adnexal region blastoid variant of mantle-cell lymphoma is an exceptional event, with only one previous case reported. [ABSTRACT FROM AUTHOR]

The expression of L-lactate dehydrogenase genes ldh1 ( Bos taurus), ldhA ( Homo sapiens), ldhA ( Rhizopus oryzae), ldh1 ( Lactobacillus plantarum), and ldh1 ( Lactobacillus pentosus) in the cells of yeast Schizosaccharomyces pombe VKPM U-3106 has been investigated. The catalytic characteristics of the enzymes encoded by these genes have been compared, and the intensity of lactic acid synthesis by the recombinant strains obtained has been evaluated. The enzymatic activity of L-lactate dehydrogenases from L. plantarum and L. pentosus was the highest (approximately 2 to 2.5 times higher than that of the mammalian enzymes), and these enzymes therefore appear to have the highest potential for the development of lactic-acid producing strains of yeast S. pombe. [ABSTRACT FROM AUTHOR]

NAD + -dependent glyceraldehyde dehydrogenases usually had lower activity in the nonphosphorylated Entner–Doudoroff (nED) pathway. In the present study, a new NAD + -dependent glyceraldehyde dehydrogenase was engineered froml-lactaldehyde dehydrogenase ofE. coli(EC: 1.2.1.22). Through comparison of the sequence alignment and the active center model, we found that a residue N286 ofl-lactaldehyde dehydrogenase contributed an important structure role to substrate identification. By free energy calculation, three mutations (N286E, N286H, N286T) were chosen to investigate the change of substrate specificity of the enzyme. All mutants were able to oxidate glyceraldehyde. Especially, N286T showed the highest activity of 1.1U/mg, which was 5-fold higher than the reported NAD + -dependent glyceraldehyde dehydrogenases, and 70% activity was retained at 55 °C after an hour. Compared tol-lactaldehyde, N286T had a one-third lowerKmvalue to glyceraldehyde. Molecular structure ofl-lactaldehyde dehydrogenase fromE. coli. [ABSTRACT FROM PUBLISHER]

The number of people who cannot consume dairy products due to intolerance or allergies to food components is increasing. Consumers are increasingly searching for alternative, nondairy beverages which have an advantageous effect on the body and which stimulate gut microflora. Previous studies have shown that Streptococcus thermophilus TM KKP 2030p can be an efficient starter culture for the fermentation of plant material and can also ensure an acceptable sensory profile and a high number of lactic acid bacteria during 4 week cold storage. The aim of this study was to determine the relative gene expression of the l-lactate dehydrogenase gene ( ldhL) in selected strain using the RT qPCR technique at particular time points. The gene expression experiments were conducted in laboratory broth (LABm) and fruit-cereal (OBPromOat) matrix with a beta-glucan additive. Levels of gene relative expression in the selected strain in these two media were correlated with the amount of l-lactate produced. The results showed that the plant matrix stimulated stronger ldhL gene expression in the first 4 h of the experiment (although the synthesis of l-lactate was less than in laboratory broth). This study broadens existing knowledge of the transcriptional mechanisms which arise from the adaptation of the analyzed strain to different habitats during l-lactate synthesis. This could contribute to the development of new alternative food products for people who show intolerance to milk proteins or lactose. [ABSTRACT FROM AUTHOR]

Objective To clone human lactate dehydrogenase B(LDH-B) gene and to construct its eukaryotic expression vector. Methods Total RNA was extracted from human breast cancer cell line MDA-MB-231 ,cDNA was generated by reverse transcription，cDNA was used as the template and the sequence segment of LDH-B gene coding region was amplified by polymerase chain reaction(PCR), both LDH-B gene segment and pUC19 plasmid were digested with two restriction endonucleases of BamH I and Kpn I，pUC19-LDH-B cloning vector was constructed by ligation reaction and then transformed into E. coli DH5a competence cells，the single white bacterial colony was selected in the blue-white selection plates' positive recombinant plasmid was identified by double restriction endonucleases digestion and DNA sequencing. Eukaryotic expression vector of pcDNA3.1 (-)- LDH-B was constructed by subcloning LDH-B gene segment with the right sequence into pcDNA3.1 (-) vector. Results A specific DNA band about 1.0 kb was found by PCR amplification，which agreed with the expected fragment length of LDH-B； two DNA bands about 2.6 kb and 1.0 kb were seen after digestion of pUC19-LDH-B with BamH I and Kpn I，which agreed with the fragment length of pUC19 and LDH-B respectively， the LDH-B sequencing result was consistent with its reference sequence in Genebank ；two DNA bands about 5.5 kb and 1.0 kb were seen after digestion of pcDNA3.1 (-)-LDH-B with BamHI and KpnI， which agreed with the fragment length of pcDNA3.1 (-) and LDH-B respectively. Conclusion Human LDH-B gene is successfully cloned in this experimental study and its eukaryotic expression vector is successfully constructed， which lays an essential foundation for further exploring LDH-B biological functions. [ABSTRACT FROM AUTHOR]

An automated method for determining whether dairy cows with subclinical mammary infections recover after antibiotic treatment would be a useful tool in dairy production. For that purpose, inline l-lactate dehydrogenase (LDH) measurements were modeled using a dynamic linear model; the variance parameters were estimated using the expectation-maximization algorithm. The method used to classify cows as infected or uninfected was based on a multiprocess Kalman filter. Two learning data sets were created: infected and uninfected. The infected data set consisted of records from 48 cows with subclinical Staphylococcus aureus infection from 4 herds collected in 2010. The uninfected data set came from 35 uninfected cows collected during 2013 from 2 herds. Bacteriological culturing was used as gold standard. To test the model, we collected data from the 48 infected cows 50 d after antibiotic treatment. As a result of the treatment, this test data set consisted of 25 cows that still had a subclinical infection and 23 cows that were recovered. Model sensitivity was 36.0% and specificity was 82.6%. To a large extent, l-lactate dehydrogenase reflected the cow's immune response to the presence of pathogens in the udder. However, cows that were classified correctly before treatment had a better chance of correct classification after treatment. This indicated a variation between cows in immune response to subclinical mammary infection that may complicate the detection of subclinically infected cows and determination of recovery. [ABSTRACT FROM AUTHOR]

l - lactate dehydrogenase (LDH) catalyzes the conversion of pyruvate to l -lactate using NADH as a cofactor. In this work, we have optimized the immobilization of LDH from rabbit muscle in glyoxyl-agarose to have an active and stable preparation which is able to synthesize l -lactic acid. Optimization of various parameters during immobilization allowed the preparation of an active and highly stable immobilized derivative of LDH. A 90.1% immobilization and 72.0% yield was achieved using 300 mM trehalose during the immobilization process. Thermal stabilization factors attained for the immobilized LDH were 1600 times greater as compared to its soluble counterpart. The immobilized preparation was also stabilized against ethanol where it recovered 75% of its initial activity after 48 h while the soluble enzyme was completely inactivated after only 10 min under the same conditions. The enzyme activity profile versus pH and temperature showed a wider range for the immobilized preparation as compared to the soluble enzyme, whilst maintaining optimal values. Production of l -lactic acid was achieved in a batch reactor with the immobilized LDH and this preparation resisted 15 reuses without the loss of activity. We believe that the immobilization strategy optimized here broadened the possibilities of utilizing LDH for biocatalytic applications. [ABSTRACT FROM AUTHOR]

Objective: To explore the relationship between serum lactate dehydrogenase(LDH) level and pre-eclampsia,adverse outcomes of pregnancy, and to confirm the predictive value of serum LDH level on pre-eclampsia. Methods:A retrospective study was performed in the present study which involved 2 236 patients with hypertensive disorders in Suzhou area of Jiangsu Province in China. The number of patients in gestational hypertension, mild and severe pre-eclampsia groups were998, 305 and 933. Logistic regression was used to analyze the association between serum LDH and pre-eclampsia, the serum LDH and clinical records were investigated, and chi-square test was used to analyze the association between serum LDH and adverse outcomes of pregnancy. Results: ① The level of LDH in group gestational hypertension was 228.0(179.6-444.0) U/L.Significant difference(P <0.01) was revealed in serum LDH level between the gestational hypertension and pre-eclampsia groups, also between mild and severe pre-eclampsia groups. ② Patients were stratified according to quartiles of serum LDH.Compared the lowest quartiles(≤179.6 U/L), the risk of pre-eclampsia increased significantly than the other three groups.Three models were used in logistic analysis, unadjusted model, adjusted model for tradition factors and adjusted model for selected factors by multiple regression. The odds ratio(OR) and 95% confidence interval(95%CI) for the three models were18.92(13.56-26.37), 13.26(9.42-18.67) and 7.97(5.37-11.84) in the highest quartiles(LDH>444.0 U/L), respectively.An obvious dose-response relationship was also showed in three models. ③ For mild and severe pre-eclampsia patients,compared with the lowest quartiles(≤200 U/L), the OR and 95%CI for the three models mentioned above were 11.56(6.74-19.83), 7.30(4.20-12.71) and 4.43(2.47-7.94) for the highest quartiles (LDH>547.0 U/L), respectively. The pathogenesis risk increased with the LDH level elevation. ④ The further ROC analysis showed that, the area under curve (AUC) of serum LDH level, the ratio of LDH/albumin, and the ratio of LDH/bilirubin for the diagnosis prediction of pre-eclampsia or severe pre-eclampsia were lower than 0.8. The predictive value of the indexes above on pre-eclampsia or severe pre-eclampsia diagnosis was limited. ⑤ When patients were stratified according to median of serum LDH, the elevation of serum LDH level was significantly (P <0.05) correlated to the adverse results of the pregnant women, fetuses and neonates in severe pre-eclampsia group. Conclusions:An obvious dose-response relationship was present between LDH level and pre-eclampsia, and LDH was an important reference biochemical marker in clinical practice, which reflected the severity of pre-eclampsia. In severe pre-eclampsia, the obvious elevation of serum LDH level might indicate the occurrence of maternal and infant adverse outcomes. Timely and effective measures might have very important significance to reduce the incidence of adverse outcomes of pregnancy, and protect the security and health of the maternal and children. [ABSTRACT FROM AUTHOR]

Exploration of cost-effective fermentation substrates for efficient lactate production is an important economic objective. Although some organic nitrogen sources are also cheaper, inorganic nitrogen salts for lactate fermentation have additional advantages in facilitating downstream procedures and significantly improving the commercial competitiveness of lactate production. In this study, we first established an application of diammonium phosphate to replace yeast extract with a reduced 90 % nitrogen cost for a thermotolerant Bacillus coagulans strain. In vivo enzymatic and transcriptional analyses demonstrated that diammonium phosphate stimulates the gene expression of L-lactate dehydrogenase, thus providing higher specific enzyme activity in vivo and increasing L-lactic acid production. This new information provides a foundation for establishing a cost-effective process for polymer-grade L-lactic acid production in an industrial setting. [ABSTRACT FROM AUTHOR]

The current study investigates the impact of mutation of 2,3-butanediol (BDO) formation pathway on glycerol metabolism and 1,3-propanediol (PDO) production by lactate dehydrogenase deficient mutant of Klebsiella pneumoniae J2B. To this end, BDO pathway genes, budA , budB , budC and budO (whole- bud operon), were deleted from K. pneumoniae J2B Δ ldhA and the mutants were studied for glycerol metabolism and alcohols (PDO, BDO) production. Δ budO -mutant-only could completely abolish BDO production, but with reductions in cell growth and PDO production. By modifying the culture medium, the Δ budO mutant could recover its performance on the flask scale. However, in bioreactor experiments, the Δ budO mutant accumulated a significant amount of pyruvate (>73 mM) in the late phase and PDO production stopped concomitantly. Glycolytic intermediates of glycerol, especially glyceraldehyde-3-phosphate (G3P) was highly inhibitory to glycerol dehydratase (GDHt); its accumulation, followed by pyruvate accumulation, was assumed to be responsible for the Δ budO mutant’s low PDO production. [ABSTRACT FROM AUTHOR]

Context: Cold-water immersion (CWI) has been applied widely as a recovery method, but little evidence is available to support its effectiveness. Objective: To investigate the effects of CWI on muscle damage, perceived muscle soreness, and muscle power recovery of the upper and lower limbs after jiu-jitsu training. Design: Crossover study. Setting: Laboratory and field. Patients or Other Participants: A total of 8 highly trained male athletes (age = 24.0 ± 3.6 years, mass = 78.4 6 2.4 kg, percentage of body fat = 13.1% 6 3.6%) completed all study phases. Intervention(s): We randomly selected half of the sample for recovery using CWI (6.08C ± 0.58C) for 19 minutes; the other participants were allocated to the control condition (passive recovery). Treatments were reversed in the second session (after 1 week). Main Outcome Measure(s): We measured serum levels of creatine phosphokinase, lactate dehydrogenase (LDH), aspartate aminotransferase, and alanine aminotransferase enzymes; perceived muscle soreness; and recovery through visual analogue scales and muscle power of the upper and lower limbs at pretraining, postrecovery, 24 hours, and 48 hours. Results: Athletes who underwent CWI showed better posttraining recovery measures because circulating LDH levels were lower at 24 hours postrecovery in the CWI condition (441.9 ± 81.4 IU/L) than in the control condition (493.6 ± 97.4 IU/L; P= .03). Estimated muscle power was higher in the CWI than in the control condition for both upper limbs (757.9 ± 125.1 W versus 695.9 ± 56.1 W) and lower limbs (53.7 ± 3.7 cm versus 35.5 ± 8.2 cm; both P values = .001). In addition, we observed less perceived muscle soreness (1.5 ± 1.1 arbitrary units [au] versus 3.1 ± 1.0 au; P = .004) and higher perceived recovery (8.8 ± 1.9 au versus 6.9 ± 1.7 au; P = .005) in the CWI than in the control condition at 24 hours postrecovery. Conclusions: Use of CWI can be beneficial to jiu-jitsu athletes because it reduces circulating LDH levels, results in less perceived muscle soreness, and helps muscle power recovery at 24 hours postrecovery. [ABSTRACT FROM AUTHOR]

Treatment with epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) has been shown to prolong survival in patients with EGFR mutation-positive non-small cell lung cancer (NSCLC). The present study performed a retrospective analysis to investigate the association between the plasma lactate dehydrogenase (LDH) levels and survival in patients with EGFR mutation-positive NSCLC receiving treatment with EGFR-TKIs. The medical charts of patients with EGFR mutation-positive NSCLC who were receiving treatment with EGFR-TKIs at Toyama University Hospital between 2007 and 2014 were assessed. The data from 65 patients were included in the analysis. Patients with higher plasma LDH levels exhibited shorter progression-free survival (6.2 vs. 13.2 months; P<0.01) and overall survival (10.5 vs. 36.1 months; P<0.01) periods compared with patients with lower plasma LDH levels. A Cox proportional hazards model identified that the plasma LDH level was associated with the progression-free survival (P=0.05) and overall survival (P<0.01). An association was demonstrated between the pretreatment plasma LDH level and the survival in patients with EGFR mutation-positive NSCLC receiving treatment with EGFR-TKIs. Close observation is required in EGFR mutation-positive NSCLC patients exhibiting high plasma LDH levels following the initiation of treatment with EGFR-TKIs. [ABSTRACT FROM AUTHOR]

Background Prior studies have shown the prognostic utility of measuring l-lactate in critically ill neonatal foals, both as single (at admission) and serial measurements. Greater prognostic sensitivity and specificity may be achieved by use of the area under the l-lactate versus time curve (LACArea) over the first 24 hours of hospitalization, which captures both severity and duration of hyperlactatemia. Prior to application of this concept in sick equine neonates, a reference interval for LACArea should be determined. Methods The concentration of lactate [LAC] was measured in blood obtained via direct jugular venipuncture from clinically normal foals on Days 1 (birth-24 h of age), 3, 7, and 14 following birth at 6-hour intervals for each 24-hour period. LACArea was calculated using the trapezoidal method. Differences in LACArea by Day were determined by MANOVA with a priori Bonferroni correction, P ≤ 0.05. Results LACArea differed by Day ( P = 0.001), being largest on Day 1, followed by Day 3. Days 7 and 14 were smallest and not different from each other. Conclusion LACArea decreases substantially and predictably over the first week of life in normal neonatal foals. Knowing how LACArea normally changes over the first 2 weeks of life will aid in future study of LACArea as it applies to sick neonatal foals, allowing for consideration of maturational changes potentially unrelated to disease. [ABSTRACT FROM AUTHOR]

Introduction: To compare the effects of hyaluronan (Gengigel) alone and in combination with scaling using clinical, microbial, and lactate dehydrogenase (LDH) parameters. Materials and Methods: In this, the three treatment groups included were scaling, scaling plus local application of Gengigel, and Gengigel alone. The 0.2% hyaluronic acid (HA) gel was applied topically and intrasulcularly 0.8% hyaluronan was applied. The clinical parameters, and microbial and biochemical analyses of gingival crevicular fluid (GCF) LDH were assessed. Intragroup comparisons were made by Student's unpaired t-test and intergroup comparisons were done using one-way analysis of variance followed by post hoc Turkey's test. Results: At the end of study period (0-56 day), intergroup comparison demonstrated no significant reduction in plaque index (PI) (0.07 NS), gingival index (GI) (0.99 NS), and LDH (0.70 NS) values. A significant correlation was found between LDH values and bleeding index at all study intervals (0 days, 28 days, and 56 days); gingival index (GI) (0.007 S) was significantly correlated on day 0 and day 56. The microbial reduction was demonstrated. Conclusion: These changes in the clinical, microbial, and biochemical parameters reported with the different treatment modalities clearly support that the use of Gengigel would act as an advantageous adjunct to scaling. Further studies are required to confirm the Gengigel effect using histologic methods. [ABSTRACT FROM AUTHOR]

The present study was undertaken to estimate the effect of occupational exposure to lead on the blood concentration of glucose and several enzymes involved in glycolysis, the citric acid cycle, and the pentose phosphate pathway. To estimate the degree of lipid peroxidation, the concentrations of conjugated dienes were determined.The examined group included 145 healthy male employees of lead–zinc works. Taking into account the mean blood lead levels, the examined group was divided into two subgroups. The control group was composed of 36 healthy male administrative workers.The markers of lead exposure were significantly elevated in both subgroups when compared with the controls. There were no significant changes in fasting glucose concentration and fructose-1,6-bisphosphate aldolase activity in the study population. The concentration of conjugated dienes was significantly higher in both subgroups, whereas the activity of malate dehydrogenase was significantly higher only in the group with higher exposure. The activities of lactate dehydrogenase and sorbitol dehydrogenase were significantly decreased in the examined subgroups. The activity of glucose-6-phosphate dehydrogenase decreased significantly in the group with higher exposure and could be the cause of the elevated concentrations of conjugated dienes.It is possible to conclude that lead interferes with carbohydrate metabolism, but compensatory mechanisms seem to be efficient, as glucose homeostasis in lead-exposed workers was not disturbed. [ABSTRACT FROM AUTHOR]