Enhancement of arachidonic acid production by Mortierella alpina 1S-4

The effect of mineral addition on arachidonic acid (AA) production by Mortierella alpina 1S-4 was evaluated. At first, the addition of minerals such as sodium, potassium, calcium, and magnesium was examined in flask cultures, and then the addition of phosphorus with the optimal amounts of the minerals was investigated in a 10-L jar-fermenter. As a result, 1.5% soy flour medium with the addition of 0.3% KH₂PO₄, 0.1% Na₂SO₄, 0.05% CaCl₂·2H₂O, and 0.05% MgCl₂·6H₂O was found to enhance the AA yield 1.7-fold over that without mineral addition. When 1% yeast extract with the above mineral mixture was used, the AA yield was enhanced 1.35-fold over that without minerals. We also verified that an increase in the polar lipid content occurred in the case of only KH₂PO₄ addition, and that the above-mentioned increase in the AA yield was due to the minerals themselves, not a pH buffer effect.     

Analyses of homo-oligomer interfaces of proteins from the complementarity of molecular surface, electrostatic potential and hydrophobicity

To extract the general structural features of interacting protein pairs, the non-redundant homo-oligomer interfaces (393 interfaces) in the PDB were analyzed using the fine-grained molecular surface, electrostatic potentials and the hydrophobicity calculated as the solvation free energy using empirical parameters. For each property, statistical analyses of the degree of complementarity were carried out, and we developed a method to judge whether interfaces were shape-complementary, electrostatic-complementary and/or hydrophobic-complementary or not. In order to search for the correlation between the property complementarity and structure of the interfaces, at first, we roughly classified all the interfaces into the following five groups according to the structure of the interface and surveyed the correlation between the shape classification and the complementary: cyclic-oligomer (69), twisted-dimer (27), dimer-parallel (14), dimer-perpendicular (109) and dimer-circular (174), where the number in the parenthesis is the number of interfaces in each group. As a result, we found the new characteristic trends as the possible necessary conditions in the formation of homo-oligomer interfaces, especially from the viewpoint of electrostatic complementarity. In addition, we also show that complementarity analyses can be used to discriminate the biological-interface from the crystallographic-interface in homo-oligomer proteins.     

Addition of Aliskiren to Angiotensin Receptor Blocker Improves Ambulatory Blood Pressure Profile and Cardiorenal Function Better than Addition of Benazepril in Chronic Kidney Disease

An altered ambulatory blood pressure (BP) and heart rate (HR) profile is related to chronic kidney disease (CKD) and cardiorenal syndrome. In this study, we examined the effects of aliskiren, when added to angiotensin II type 1 receptor blockers, on ambulatory BP and cardiorenal function in CKD. Thirty-six hypertensive CKD patients were randomly assigned to the aliskiren add-on group (n = 18) or the benazepril add-on group (n = 18). Ambulatory BP and cardiorenal function parameters were measured at baseline and 24 weeks after treatment. Compared with the benazepril group, nighttime systolic BP variability in the aliskiren group was lower after treatment. Albuminuria was decreased in the aliskiren group, but not in the benazepril group. In addition, left ventricular mass index (LVMI) was significantly lower in the aliskiren group than in the benazepril group after treatment. In the aliskiren group, multivariate linear regression analysis showed an association between changes in albuminuria and changes in nighttime systolic BP. Furthermore, there were associations between changes in LVMI and changes in daytime HR variability, as well as between changes in LVMI and changes in plasma aldosterone concentration. These results suggest that aliskiren add-on therapy may be beneficial for suppression of renal deterioration and pathological cardiac remodeling through an improvement that is effected in ambulatory BP and HR profiles.     

Production of epsilon-polylysine in an airlift bioreactor (ABR)

This paper deals with studies on epsilon-poly-L-lysine (epsilon-PL) production in an airlift bioreactor (ABR) using Streptomyces albulus S410 (S410) to minimize the production cost including the downstream processing of epsilon-PL. In a 5-l ABR, 30 g/l of epsilon-PL was produced with a power consumption of 0.3 kW/m3, the production level being similar to that in a 5-l jar fermentor with a power consumption of 8.0 kW/m3. Furthermore, the leakage of intracellular nucleic acid (INA)-related substances into the culture broth in the ABR was less than that in the jar fermentor. Due to the high-level power consumption (8.0 kW/m3) in the jar fermentor, the morphology of the cells changed from the pellet to filament form due to the extensive shear stress arising from continuous agitation, thereby increasing the leakage of the INA-related substances into the culture broth. This suggested that ABR would have an advantage in the low-cost production of epsilon-PL over stirred tank type reactors (STR).     

Reaction Kinetics of Coke and some Carbonaceous Materials with CO2 and Coke Strength after Reaction

The reaction rate per unit mass of wood char was an order of magnitude larger than that of coke and graphite and that of glassy carbon was an order of magnitude smaller than the latter. However, the reaction rate per unit surface area of wood char was smaller than that of graphite. The reaction of coke proceeded homogeneously at temperatures lower than 1373 K, while the reaction was restricted to the surface layer at higher temperatures. The tensile strength of coke after reaction decreased with the reaction degree at 1273 K, but was not changed or even increased at 1573 K. This is due to the fact that at 1573 K the core of the sample was not attacked by CO₂ but strengthened by further crystallization.     

Scenario-based Impact Assessment of Land Use/Cover and Climate Changes on Water Resources and Demand: A Case Study in the Srepok River Basin,Vietnam—Cambodia

This study investigates an interdisciplinary scenario analysis to assess the potential impacts of climate, land use/cover and population changes on future water availability and demand in the Srepok River basin, a trans-boundary basin. Based on the output from a high-resolution Regional Climate Model (ECHAM 4, Scenarios A2 and B2) developed by the Southeast Asia—System for Analysis, Research and Training (SEA-START) Regional Center, future rainfall was downscaled to the study area and bias correction was carried out to generate the daily rainfall series. Land use/cover change was quantified using a GIS-based logistic regression approach and future population was projected from the historical data. These changes, individually or in combination, were then input into the calibrated hydrological model (HEC-HMS) to project future hydrological variables. The results reveal that surface runoff will be increased with increased future rainfall. Land use/cover change is found to have the largest impact on increased water demand, and thus reduced future water availability. The combined scenario shows an increasing level of water stress at both the basin and sub-basin levels, especially in the dry season.     

Preparation and Characterization of a Large-Scale YBa2Cu3O7−x Superconductor Prepared by Plastic Forming without a High-Pressure Molding: Effect of Polyvinyl Alcohol (PVA) Addition on the Superconducting Properties

The preparation of large-scale YBa₂Cu₃O_{7− x} superconductor samples was investigated. This method is based on plastic forming using a slurry consisting of YBa₂Cu₃O_{7− x} particles and a sol solution made up of multimetallic hydroxide particles (YBa₂Cu₃(OH) _x colloidal particles) and poly(vinyl) alcohol (PVA). The effects of adding PVA on the product, the crystallinity, and the superconducting properties of the sample were investigated. It was found that PVA acted as a protective colloid in the sol solution and stabilized YBa₂Cu₃(OH) _x colloidal particles, and that the role of PVA changed from a thickener to a flocculant during drying so that the formability/workability of the green sheet sample was improved and large samples (about 80 mm × 80 mm × 3 mm) without large cracks were obtained after firing. The samples became superconducting at 91.5±0.5 K ( T _con) and the full transition temperature ( T _coff) was 88.5±1.5 K. The critical current density ( J _c) of the sample prepared from the slurry containing 1 wt% PVA was 713±150 A/cm² at 77 K. This J _c value was improved to 2300 A/cm² by heat treatment at 773 K under an oxygen atmosphere.     

热轧钢/热轧钢摩擦副干摩擦高温摩擦行为的研究

用多功能SRV试验机评价了热轧钢/热轧钢摩擦副在干摩擦条件下的高温减摩抗磨性能,并对高温磨损表面进行了分析.结果表明,在试验范围内热轧钢/热轧钢摩擦副的高温摩擦系数随时间的延长呈增长趋势,增长趋势的快慢与试验参数有关,高速时的高温摩擦系数明显低于低速时的高温摩擦系数;大量氧化铁磨屑的产生是造成热轧钢/热轧钢摩擦副高温摩擦系数上下波动的主要原因.试验速度对热轧钢/热轧钢摩擦副的高温磨损机理有很大的影响,在高速（0.32m/s）条件下,高温磨损机理主要是磨粒磨损;而在低速（0.10m/s）条件下,高温磨损机理主要是粘着磨损.     

Production of 8,11,14,17-cis-eicosatetraenoic acid by Δ5 desaturase-defective mutants of an arachidonic acid-producing fungus, Mortierella alpina

Δ5 Desaturase-defective mutants of an arachidonic acid-producing fungus, Mortierella alpina 1S-4, accumulate large amounts of 8,11,14,17-cis-eicosatetraenoic acid (20:4ω3) when grown with linseed oil. One of the mutants, the S14 strain, produced 1.65 mg of 20:4ω3 per mL of culture medium (corresponding to 66.0 mg/g dry mycelia and 11.6% of total cellular fatty acids) when grown in a medium containing 1% glucose, 1% yeast extract, and 4% linseed oil methyl ester at 28°C for 2 d, and then at 16°C for 7 d. In a bench-scale fermentation in a 5-L jar fermenter, 20:4ω3 production reached 1.60 g/L of culture medium on the eighth day (corresponding to 77.3 mg/g dry mycelia and 26.0% of total cellular fatty acids). The cellular lipids of the S14 strain comprised 75.8% triacylglycerol (TG), 6.7% diacylglycerol, and 13.3% phospholipids (PL). The percentage of 20:4ω3 was higher in PL than in TG, and highest in phosphatidylcholine (32.6%).