Baicalin attenuates neuronal damage associated with SDH activation and PDK2-PDH axis dysfunction in early reperfusion.

BACKGROUND: Energy deficiency and oxidative stress are interconnected during ischemia/reperfusion (I/R) and serve as potential targets for the treatment of cerebral ischemic stroke. Baicalin is a neuroprotective antioxidant, but the underlying mechanisms are not fully revealed. PURPOSE: This study explored whether and how baicalin rescued neurons against ischemia/reperfusion (I/R) attack by focusing on the regulation of neuronal pyruvate dehydrogenase kinase 2 (PDK2)-pyruvate dehydrogenase (PDH) axis implicated with succinate dehydrogenase (SDH)-mediated oxidative stress. STUDY DESIGN: The effect of the tested drug was explored in vitro and in vivo with the model of oxygen-glucose deprivation/reoxygenation (OGD/R) and middle cerebral artery occlusion/reperfusion (MCAO/R), respectively. METHODS: Neuronal damage was evaluated according to cell viability, infarct area, and Nissl staining. Protein levels were measured by western blotting and immunofluorescence. Gene expression was investigated by RT-qPCR. Mitochondrial status was also estimated by fluorescence probe labeling. RESULTS: SDH activation-induced excessive production of reactive oxygen species (ROS) changed the protein expression of Lon protease 1 (LonP1) and hypoxia-inducible factor-1ɑ (HIF-1ɑ) in the early stage of I/R, leading to an upregulation of PDK2 and a decrease in PDH activity in neurons and cerebral cortices. Treatment with baicalin prevented these alterations and ameliorated neuronal ATP production and survival. CONCLUSION: Baicalin improves the function of the neuronal PDK2-PDH axis via suppression of SDH-mediated oxidative stress, revealing a new signaling pathway as a promising target under I/R conditions and the potential role of baicalin in the treatment of acute ischemic stroke.

Evaluation of enhancing effect of soybean oil on polymalic acid production by Aureobasidium pullulans HA-4D.

Polymalic acid (PMA) is a water-soluble polyester produced by Aureobasidium pullulans. In this study, the physiological response of A. pullulans after the addition of vegetable oils was investigated. Soybean oil (SBO) is pivotal for shortening fermentation time and achieving high PMA titer. With the addition of 1% (w/v) SBO, the titer and productivity of PMA was, respectively, increased by 34.2% and 80%. SBO acted as a chemical stimulatory agent rather than a carbon source, the enhancement on PMA production was attributed to the component of fatty acid. SBO induced the dimorphism (yeast-like cells and mycelia) of A. pullulans, in vitro enzyme activities indicated that the TCA oxidative branch for malic acid synthesis might be strengthened, which could generate more ATP for PMA synthesis, and the assay of intracellular energy supply validated this deduction. This study provided a new sight for recognizing the regulatory behavior of SBO in A. pullulans.

Novel two-stage solid-state fermentation for erythritol production on okara-buckwheat husk medium.

An economical model of two-stage solid state fermentation (SSF) (prefermentation stage with Mucor flavus and in situ erythritol fermentation stage with Yarrowia lipolytica) for enhancing erythritol production was investigated. Buckwheat husk (BH) was utilized as inert support for the first time and okara as the substrate. Morphological properties suggested yeast cells were exposed in adequate oxygen leading to high erythritol yield, and enzyme activities analysis indicated M. flavus and Y. lipolytica grew and cooperated well during the two ferment stages. Maximum erythritol production (143.3 mg/gds) was obtained from okara-BH mixture (5:2, w/w) supplemented with 0.01 g/gds NaCl, with an initial moisture content of 60% and pH of 4.0 for 192 h, while undesired mannitol and citric acid were suppressed. Compared with submerged fermentation, two-stage SSF was short period, energy conserving and operable for erythritol production from insoluble wastes, and this is the first report on erythritol production via SSF.

Citric acid production in Yarrowia lipolytica SWJ-1b yeast when grown on waste cooking oil.

In this study, citric acid was produced from waste cooking oil by Yarrowia lipolytica SWJ-1b. To get the maximal yield of citric acid, the compositions of the medium for citric acid production were optimized, and our results showed that extra nitrogen and magnesium rather than vitamin B1 and phosphate were needed for CA accumulation when using waste cooking oil. The results also indicated that the optimal initial concentration of the waste cooking oil in the medium for citric acid production was 80.0 g/l, and the ideal inoculation size was 1 × 10(7) cells/l of medium. We also reported that during 10-l fermentation, 31.7 g/l of citric acid, 6.5 g/l of isocitric acid, 5.9 g/l of biomass, and 42.1 g/100.0 g cell dry weight of lipid were attained from 80.0 g/l of waste cooking oil within 336 h. At the end of the fermentation, 94.6 % of the waste cooking oil was utilized by the cells of Y. lipolytica SWJ-1b, and the yield of citric acid was 0.4 g/g waste cooking oil, which suggested that waste cooking oil was a suitable carbon resource for citric acid production.

Antithrombotic effect of a novel protein from Fusarium sp. CPCC 480097 in a rat model of artery-vein bypass thrombosis.

CONTEXT: The incidence and mortality of thrombotic disorders are rapidly increasing throughout the world. Therefore, attempts have been made to develop new anticoagulant and antithrombotic drugs. Our previous studies showed that a novel protein, named Fu-P, had fibrinogenolytic activity and much higher fibrinolytic activity on the fibrin plate than urokinase in vitro. OBJECTIVE: The antithrombotic activities of Fu-P in vivo are investigated here for the first time. MATERIALS AND METHODS: Antithrombotic activity of Fu-P was studied in a rat model of artery-vein bypass thrombosis. The anticoagulant activity of Fu-P was measured by clotting assay of activated partial thrombinplastin time and prothrombin time (PT). The effects of Fu-P on the factor Xa and thrombin were assayed using the chromogenic substrate S-2765 and S-2238. RESULTS: Intravenous injection of Fu-P produced a 58.4% inhibition ratio of thrombus formation at 0.1 mg/kg body weight, while heparin produced 42.5% inhibition ratio of thrombus formation at 0.6 mg/kg body weight. Fu-P significantly prolonged fibrinogen clotting time, activated partial thrombinplastin time and thrombin time, which also prolonged PT. The inhibition assay of the coagulant factors using chromogenic substrates S-2238 and S-2765 showed that Fu-P was not the inhibitor of the thrombin and Xa. DISCUSSION AND CONCLUSION: These findings demonstrated that the novel fibrinolytic enzyme (Fu-P) might also be used as a natural agent for thrombolytic therapy or thrombosis prevention.