BACKGROUNDStreptococcus (S.) oligofermentans is a newly identified bacteria with a yet to be defined mechanism of sucrose metabolism that results in acid production. This study aimed to investigate the biochemical mechanisms of S. oligoferm-entans glucose metaolism.

METHODSThe S. oligofermentans LMG21532, Lactobacillus (L.) fermentum 38 and the S. mutans UA140 were used to characterize sucrose metabolism by measuring lactate dehydrogenase (LDH) activity and lactic acid production. Continuous dynamics and high performance capillary electrophoresis were used to determine LDH activity and lactic acid production, respectively, from bacteria collected at 0, 10 and 30 minutes after cultured in 10% sucrose.

RESULTSThese analyses demonstrated that LDH activity of the three bacterial strains examined remained stable but significantly different throughout the sucrose fermentation process. The S. oligofermentans LDH activity ((0.61 ± 0.05) U/mg) was significantly lower than that of L. fermentum ((52.91 ± 8.97) U/mg). In addition, the S. oligofermentans total lactate production ((0.048 ± 0.021) mmol/L) was also significantly lower than that of L. fermentum ((0.958 ± 0.201) mmol/L). Although the S. oligofermentans LDH production was almost double of that produced by S. mutans ((0.32 ± 0.07) U/mg), lactic acid production was approximately one sixth that of S. mutans ((0.296 ± 0.058) mmol/L). Additional tests examining pyruvic acid production (the LDH substrate) demonstrated that lactic acid concentrations correlated with pyruvic acid production. That is, pyruvic acid production by S. oligofermentans was undetectable following sucrose incubation, however, (0.074 ± 0.024) and (0.175 ± 0.098) mmol/L pyruvic acid were produced by S. mutans and L. fermentum, respectively.

CONCLUSIONS. oligofermentans is incapable of fermenting carbohydrates to produce enough pyruvic acid, which results in reduced lactic acid production.

L-Lactate Dehydrogenase ; metabolism ; Lactic Acid ; metabolism ; Pyruvic Acid ; metabolism ; Streptococcus ; metabolism ; Sucrose ; metabolism

Lactic acid has a wide range of uses in the chemical, pharmaceutical and food industry. With rapid development of poly (lactic acid) industry, the demand for polymer-grade L-lactic acid is continuously increasing. Developing low-cost, non-food-biomass-lactic-acid fermentation process and the fermentation-separation coupled technology are trends to reduce polymer-grade L-lactic acid production cost. This review summarized the most recent advances in low-cost L-lactic acid fermentation based on the use of non-food biomass, followed by addressing the key issue that might be strategically important for future development of polymer-grade L-lactic acid production in industry.
Biomass ; Biotechnology ; trends ; Cellulose ; metabolism ; Fermentation ; Insulin ; metabolism ; Lactic Acid ; metabolism ; Manihot ; metabolism ; Polymers ; metabolism

Tumor cells have unique energy metabolism phenomena, namely high glucose absorption, aerobic glycolysis and high lactic acid production, which are characterized by down-regulation of related proteins involved in oxidative metabolism in tumor cells, and up-regulation of glucose transporters and monocarboxylate transporters. Studies have shown that drugs that target tumor cell glucose metabolism have the ability to selectively kill tumor cells, bringing new hope for tumor treatment. Tumor stem cells are considered to be the root cause of tumor recurrence, metastasis and poor prognosis, and their energy metabolism characteristics have not yet been agreed. Studies have shown that reversing the energy metabolism of tumor stem cells can increase their chemosensitivity. This article reviews recent studies on tumor and tumor stem cell glucose metabolism and the opportunities and challenges of tumor treatment through targeting glucose metabolism, which might provide new ideas and opportunities for clinical tumor therapy.
Energy Metabolism ; Glucose ; metabolism ; Glycolysis ; Humans ; Lactic Acid ; metabolism ; Neoplasms ; metabolism ; Neoplastic Stem Cells ; metabolism

Localized, water-suppressed in vivo 'H MRS was performed to evaluated the proton metabolic alterations in patients with acute cerebral infarction.Ten brain infarction patients(six males and four females; age range 53-77) participated in this study. GE Signa 1.5-T whole-body NMI/MRS system using STEAM pulse sequence was used. Voxels were selected from the cerebral infarcted region and contralateral normal region as control in the same patient. Proton metaboliteratiosrelativetocreatine (Cr) wereobtainedusingaMa-rquartalgorithm. The specific features in the cerebral infarcted regions demonstrated a significant decrease of N-acetyl aspartate (NAA)/creatine (Cr) ratio, compared with control regions. Markedly increased lactate (Lac) level was observed in areas of cerebral infarctioln in all patients. Our preliminary study showed that NAA/Cr ratio in the infarcted regions was substanially different from that in control regions.The signal intensity of Lac may be served as a metabolic criterion that can specify acuteness of infarction, and also evaluate the therapeutic effect. It is necessary to investigate the spectral alterations in various stages of cerebral infarction for further detail analysis.
Aspartic Acid ; Brain Infarction ; Cerebral Infarction* ; Female ; Humans ; Infarction ; Lactic Acid ; Male ; Metabolism ; Protons ; Steam

In order to carry out the process of the repeated intermittent L-lactic acid fermentation by self-immobilized Rhizopus oryzae, we investigated the effect of medium compositions on the morphology of Rhizopus oryzae. In submerged culture, fungi can be grown as broths of freely suspended mycelia and pellets or clumps, the pellets can be immobilized by themselves. The optimum medium composition for the first patch of fermentation was: 120 g/L glucose, 3 g/L NH4NO3, 0.14 g/L KH2PO4, 0.16 g/L NaH2PO4 (the concentration ratio of K+ and Na+ was 1:1). After 72 h fermentation, the physical form of Rhizopus oryzae was mostly uniform pellet with the diameter of 1.0-2.0 mm, the concentration of L-lactic acid was 100.8 g/L, and the conversion rate of glucose was 84%. During 16 batches of repeated fermentation, the L-lactic acid level was above 60.0 g/L and the conversion rate of glucose was 75%. The fermentation time of every batch was 24 h.
Cells, Immobilized ; metabolism ; Culture Media ; Fermentation ; Lactic Acid ; biosynthesis ; Rhizopus ; growth & development ; metabolism

The key to the treatment of septic shock is to provide adequate oxygen supply and improve tissue perfusion. Lactate and central venous oxygen saturation (ScvO) are commonly used as the indices of oxygen metabolism, but tissue hypoxia may still exist even when lactate and ScvOare within the normal range. Arteriovenous difference in carbon dioxide partial pressure (COgap) can accurately reflect oxygen delivery when ScvOis in the normal range. This article reviews the advantages and shortages of lactate, lactate clearance rate, ScvO, and COgap in evaluating tissue hypoxia, in order to provide a reference for treatment and severity evaluation of septic shock.
Carbon Dioxide ; blood ; Humans ; Lactic Acid ; metabolism ; Metabolic Clearance Rate ; Oxygen ; blood ; Shock, Septic ; metabolism

The aim of this paper is to explore the prevention of rabbit postoperative abdominal cavity adhesion with poly (lactic-co-glycotic acid) (PLGA) membrane and the mechanism of this prevention function. Sixty-six Japanese white rabbits were randomly divided into normal control group, model control group and PLGA membrane group. The rabbits were treated with multifactor methods to establish the postoperative abdominal cavity adhesion models except for those in the normal control group. PLGA membrane was used to cover the wounds of rabbits in the PLGA membrane group and nothing covered the wounds of rabbits in the model control group. The hematologic parameters, liver and kidney functions and fibrinogen contents were detected at different time. The rabbit were sacrificed 1, 2, 4, 6, 12 weeks after the operations, respectively. The adhesions were graded blindly, and Masson staining and immunohistochemistry methods were used to observe the proliferation of collagen fiber and the expression of transforming growth factor β1 (TGF-β1) on the cecal tissues, respectively. The grade of abdominal cavity adhesion showed that the PLGA membrane-treated group was significant lower than that in the model control group, and it has no influence on liver and kidney function and hematologic parameters. But the fibrinogen content and the number of white blood cell in the PLGA membrane group were significant lower than those of model control group 1 week and 2 weeks after operation, respectively. The density of collagen fiber and optical density of TGF-β1 in the PLGA membrane group were significant lower than those of model control group. The results demonstrated that PLGA membrane could be effective in preventing the abdominal adhesions in rabbits, and it was mostly involved in the reducing of fibrinogen exudation, and inhibited the proliferation of collagen fiber and over-expression of TGF-β1.
Abdominal Cavity ; surgery ; Animals ; Collagen ; metabolism ; Lactic Acid ; Polyglycolic Acid ; Rabbits ; Tissue Adhesions ; prevention & control ; Transforming Growth Factor beta1 ; metabolism

Fermentative production of lactic acid, an important bio-based chemicals, has made considerable progress. In addition to the food industry and production of polylactic acid, lactic acid also can be used as an important platform chemical for the production of acrylic acid, pyruvic acid, 1,2-propanediol, and lactic acid esters. This article summarizes the recent progress in biocatalytic production of lactic acid derivatives by dehydration, dehydrogenation, reduction, and esterification. Trends in the biotransformation of lactic acid are also discussed.
Acrylates ; metabolism ; Bacteria ; genetics ; metabolism ; Biotechnology ; methods ; Biotransformation ; Fermentation ; Industrial Microbiology ; methods ; Lactic Acid ; metabolism ; Propylene Glycol ; metabolism ; Pyruvic Acid ; metabolism ; Yeasts ; genetics ; metabolism

Emerging evidence has emphasized the importance of cancer therapies targeting an abnormal metabolic state of tumor-initiating cells (TICs) in which they retain stem cell-like phenotypes and nicotinamide adenine dinucleotide (NAD⁺) metabolism. However, the functional role of NAD⁺ metabolism in regulating the characteristics of TICs is not known. In this study, we provide evidence that the mitochondrial NAD⁺ levels affect the characteristics of glioma-driven SSEA1⁺ TICs, including clonogenic growth potential. An increase in the mitochondrial NAD⁺ levels by the overexpression of the mitochondrial enzyme nicotinamide nucleotide transhydrogenase (NNT) significantly suppressed the sphere-forming ability and induced differentiation of TICs, suggesting a loss of the characteristics of TICs. In addition, increased SIRT3 activity and reduced lactate production, which are mainly observed in healthy and young cells, appeared following NNT-overexpressed TICs. Moreover, in vivo tumorigenic potential was substantially abolished by NNT overexpression. Conversely, the short interfering RNA-mediated knockdown of NNT facilitated the maintenance of TIC characteristics, as evidenced by the increased numbers of large tumor spheres and in vivo tumorigenic potential. Our results demonstrated that targeting the maintenance of healthy mitochondria with increased mitochondrial NAD⁺ levels and SIRT3 activity could be a promising strategy for abolishing the development of TICs as a new therapeutic approach to treating aging-associated tumors.
Glioblastoma* ; Lactic Acid ; Metabolism ; Mitochondria ; NAD ; NADP Transhydrogenases ; Phenotype ; Tics ; Up-Regulation*

The purpose of this study is to investigate the effect of methylprednisolone(M.P.) on the alterations of ATP, sum of adenosine nucleotides, adenylate energy charge(E.C.), glucose and lactate in the cats with acute focal ischemic cerebral edema. The acute occlusion of left middle cerebral artery(MCA) of forty cats for 1,3 and 5 hours respectively were accomplished by applying Heifetz clip through the transorbital approach operating microscope. Twelve cats were not recirculated as a untreated group, twelve cats were recirculated for 2 hours as a ecirculation group and twelve cats were recirculated for 2 hours and given M.P.(15mg/kg) at 30 minutes after occlusion initially, and then every one and a half hour as a treatment group. The experimental results are as follows. 1) In 1-hour untreated group, ATP was reduced to 34.0%, sum of adenosine nucleotides reduced to 72.2%, adenylate E.C. reduced to 60.6%, glucose reduced to 67.3% and lactate increased to 156.6% of the control value. In the recirculation group, ATP was reduced to 42.0%, sum of adenosine nucleotides reduced to 82.4%, adenylate E.C. reduced to 74.3%, glucose increased to 552.7% and lactate decreased to 79.8%. In the treatment group, ATP was increased to 143.9%, sum of adenosine nucleotides increased to 153.9%, adenylate E.C. decreased to 92.9%, glucose increased to 3334.5% and lactate decreased to 74.6%. 2) In 3-hour untreated group, ATP was decreased to 24.9%, sum of adenosine nucleotides reduced to 22.9%, adenylate E.C. reduced to 58.6%, glucose decreased to 45.5% and lactate increased to 161.3% of the control value. In the recirculation group, ATP reduced to 32.9%, sum of adenosine nucleotides reduced to 28.6%, adenylate E.C. reduced to 71.4%, glucose rose to 520.0% and lactate to 135.3% of the control value. In the treatment group, ATP reduced to 99.5%, sum of adenosine nucleotides increased to 103.5%, adenylate E.C. decreased to 84.3%, glucose rose to 1187.3% and lactate increased to 101.2%. 3) In 5-hour untreated group, ATP decreased to 5.3%, sum of adenosine nucleotides reduced to 9.0%, adenylate E.C. reduced to 58.6%, glucose decreased to 25.5% and lactate increased to 187.9%. In the recirculation group, ATP decreased to 4.4%, sum of adenosine nucleotides decreased to 5.8%, adenylate E.C. decreased to 57.1%. In the treatment group, ATP was reduced to 11.2%, sum of adenosine nucleotides and adenylate E.C. reduced to 70.0%, glucose rose to 103.6% and lactate to 157.2% of the control value. As the results shown above, the therapeutic beneficial effects of M.P. were observed in cats of 1 or 3-hour occlusion of MCA with 2-hour recirculation.
Adenosine ; Adenosine Triphosphate ; Animals ; Brain Edema ; Cats ; Energy Metabolism* ; Glucose ; Ischemia* ; Lactic Acid ; Methylprednisolone* ; Nucleotides