Fermentative intensity of L-lactic acid production using self-immobilized pelletized Rhizopus oryzae

L-Lactic acid is a promising three-carbon building-block chemical, widely used in the food, pharmaceutical, leather and textile industries and Rhizopus oryzae is an important filamentous fungus for the production of L-lactic acid with high optical purity. This study investigated the medium compositions for the maximum biomass cultivation of R. oryzae L-lactic acid fermentation, and optimized the operation parameters for semi-continuous repeated fermentation in a stirred tank fermentor using response surface method (RSM) analysis. The results indicated that a higher biomass cultivation of 3.750±0.05 g/L was achieved when the medium was composed of 12% (w/v) glucose, 0.4% (w/v) ammonium sulfate and 0.045% (w/v) monopotassium phosphate. The optimal fermentation conditions for the initial batch were as follows: the aeration was 0.75 L/(L·min), inoculation of germs was 11% and agitation speed was 560 rpm. The fermentative intensity of the initial batch and the sequentially repeated batches with self-immobilized pelletized R. oryzae were 2.162 g/(L·h) and 3.704 g/(L·h), respectively. Key words: Self-immobilized, Rhizopus oryzae, pellet, lactic acid, response surface method (RSM)

Endovascular management of spontaneous axillary artery aneurysm: a case report and review of the literature

INTRODUCTION: Spontaneous atraumatic true axillary artery aneurysm is a relatively unusual disorder. Although most cases are asymptomatic, complications of axillary artery aneurysms may result in acute vascular insufficiency and neurological deficits. Prompt treatment, therefore, should be employed in the management of this condition. To date, the standard treatment for peripheral aneurysms is still surgical resection with end-to-end anastomosis. However, aneurysmectomy and interposition grafting with autologous or artificial vessels are more invasive and time-consuming. The ideal treatment for axillary artery aneurysm should be relatively noninvasive, safe and free of significant complications, cost-effective, cosmetically acceptable, and incur less absence from usual daily activities. Endovascular stent grafts have also been successfully used to treat these aneurysms. Management of select aneurysms using stent grafts has become more prevalent with the developing endoluminal technology. CASE PRESENTATION: We report a case of a spontaneous atraumatic axillary artery aneurysm where the patient was a 48-year-old ethnic Han Chinese woman with a gradually enlarging left axillary pulsatile mass. She was treated with endovascular stent grafts. The postoperative course of the patient was uneventful during the six-month follow-up. CONCLUSIONS: We show that there are significant early advantages with the endovascular management technique versus the conventional operation in the management of axillary artery aneurysm

Interactions of the apolipoprotein C-III 3238C>G polymorphism and alcohol consumption on serum triglyceride levels

<p>Abstract</p> <p>Background</p> <p>Both apolipoprotein (Apo) C-III gene polymorphism and alcohol consumption have been associated with increased serum triglyceride (TG) levels, but their interactions on serum TG levels are not well known. The present study was undertaken to detect the interactions of the ApoC-III 3238C>G (rs5128) polymorphism and alcohol consumption on serum TG levels.</p> <p>Methods</p> <p>A total of 516 unrelated nondrinkers and 514 drinkers aged 15-89 were randomly selected from our previous stratified randomized cluster samples. Genotyping of the ApoC-III 3238C>G was performed by polymerase chain reaction and restriction fragment length polymorphism combined with gel electrophoresis, and then confirmed by direct sequencing. Interactions of the ApoC-III 3238C>G genotype and alcohol consumption was assessed by using a cross-product term between genotypes and the aforementioned factor.</p> <p>Results</p> <p>Serum total cholesterol (TC), TG, high-density lipoprotein cholesterol (HDL-C), ApoA-I and ApoB levels were higher in drinkers than in nondrinkers (<it>P </it>< 0.05-0.001). There was no significant difference in the genotypic and allelic frequencies between the two groups. Serum TG levels in nondrinkers were higher in CG genotype than in CC genotype (<it>P </it>< 0.01). Serum TC, TG, low-density lipoprotein cholesterol (LDL-C) and ApoB levels in drinkers were higher in GG genotype than in CC or CG genotype (<it>P </it>< 0.01 for all). Serum HDL-C levels in drinkers were higher in CG genotype than in CC genotype (<it>P </it>< 0.01). Serum TC, TG, HDL-C and ApoA-I levels in CC genotype, TC, HDL-C, ApoA-I levels and the ratio of ApoA-I to ApoB in CG genotype, and TC, TG, LDL-C, ApoA-I and ApoB levels in GG genotype were higher in drinkers than in nondrinkers (<it>P </it>< 0.05-0.01). But the ratio of ApoA-I to ApoB in GG genotype was lower in drinkers than in nondrinkers (<it>P </it>< 0.01). Multivariate logistic regression analysis showed that the levels of TC, TG and ApoB were correlated with genotype in nondrinkers (<it>P </it>< 0.05 for all). The levels of TC, LDL-C and ApoB were associated with genotype in drinkers (<it>P </it>< 0.01 for all). Serum lipid parameters were also correlated with age, sex, alcohol consumption, cigarette smoking, blood pressure, body weight, and body mass index in both groups.</p> <p>Conclusions</p> <p>This study suggests that the ApoC-III 3238CG heterozygotes benefited more from alcohol consumption than CC and GG homozygotes in increasing serum levels of HDL-C, ApoA-I, and the ratio of ApoA-I to ApoB, and lowering serum levels of TC and TG.</p

Constraining ultralight vector dark matter with the Parkes Pulsar Timing Array second data release

Composed of ultralight bosons, fuzzy dark matter provides an intriguing solution to challenges that the standard cold dark matter model encounters on sub-galactic scales. The ultralight dark matter with mass $m\sim10^{-23} \rm{eV}$ will induce a periodic oscillation in gravitational potentials with a frequency in the nanohertz band, leading to observable effects in the arrival times of radio pulses from pulsars. Unlike scalar dark matter, pulsar timing signals induced by the vector dark matter are dependent on the oscillation direction of the vector fields. In this work, we search for ultralight vector dark matter in the mass range of $[2\times 10^{-24}, 2\times 10^{-22}]{\rm{eV}}$ through its gravitational effect in the Parkes Pulsar Timing Array (PPTA) second data release. Since no statistically significant detection is made, we place $95\%$ upper limits on the local dark matter density as $\rho_{\rm{\tiny{VF}}} \lesssim 5{\rm{GeV/cm^{3}}}$ for $m\lesssim 10^{-23}{\rm{eV}}$. As no preferred direction is found for the vector dark matter, these constraints are comparable to those given by the scalar dark matter search with an earlier 12-year data set of PPTA.Comment: 9 pages, 3 figures, 2 tables; accepted for publication as a Letter in Phys. Rev.

Phase Diagram of Pressure-induced Superconductivity and its Relation to Hall Coefficient in Bi2Te3 Single Crystal

Pressure-induced superconductivity and its relation to corresponding Hall coefficient (RH) have been reported for Bi2Te3, one of known topological insulators. A full phase diagram is presented which shows a complex dependence of the superconducting transition temperature as a function of pressure over an extensive range. High-pressure RH measurements reveal a close relation of these complex behaviors, particularly, a dramatic change of dRH/dP before structural phase transition and a pressure-induced crossover on RH in the high pressure phase were observed.Comment: 14 pages and 3 figure

Heterologous signal peptides-directing secretion of Streptomyces mobaraensis transglutaminase by Bacillus subtilis

Microbial transglutaminase (MTG) from Streptomyces mobaraensis has been widely used for crosslinking proteins in order to acquire products with improved properties. To improve the yield and enable a facile and efficient purification process, recombinant vectors, harboring various heterologous signal peptide-encoding fragments fused to the mtg gene, were constructed in Escherichia coli and then expressed in Bacillus subtilis. Signal peptides of both WapA and AmyQ (SP wapA and SP amyQ ) were able to direct the secretion of pre-pro-MTG into the medium. A constitutive promoter (P hpaII ) was used for the expression of SP wapA -mtg, while an inducible promoter (P lac ) was used for SP amyQ -mtg. After purification from the supernatant of the culture by immobilized metal affinity chromatography and proteolysis by trypsin, 63.0 ± 0.6 mg/L mature MTG was released, demonstrated to have 29.6 ± 0.9 U/mg enzymatic activity and shown to crosslink soy protein properly. This is the first report on secretion of S. mobaraensis MTG from B. subtilis, with similar enzymatic activities and yields to that produced from Escherichia coli, but enabling a much easier purification process

Systemic Revealing Pharmacological Signalling Pathway Networks in the Hippocampus of Ischaemia-Reperfusion Mice Treated with Baicalin

Background. Baicalin (BA) exhibits ill understood neuroprotective, anti-inflammatory, and antioxidative effects in brain injury. Objective. To identify the differential network pathways associated with BA-related biological effects. Methods. MCAO-induced mice received BA 5 mg/Kg (BA group). Controls received vehicle only. Following ischaemia-reperfusion, ArrayTrack analysed the whole genome microarray of hippocampal genes, and MetaCore analysed differentially expressed genes. Results. Four reversing pathways were common to BA and controls, but only 6 were in the top 10 for BA. Three of the top 5 signalling pathways in controls were not observed in BA. BA treatment made absent 3 pathways of the top 5 signalling pathways from the top 5 in controls. There were 2 reversing pathways between controls and BA that showed altered gene expression. Controls had 6 networks associated with cerebral ischaemia. After BA treatment, 9 networks were associated with cerebral ischaemia. Enrichment analysis identified 10 significant biological processes in BA and controls. Of the 10 most significant molecular functions, 7 were common to BA and controls, and only 3 occurred in BA. BA and controls had 7 significant cellular components. Conclusions. This study showed that the clinical effectiveness of BA was based on the complementary effects of multiple pathways and networks