The Emi2 Protein of Saccharomyces cerevisiae is a Hexokinase Expressed under Glucose Limitation

Hexokinases catalyze glucose phosphorylation at the first step in glycolysis in eukaryotes. In the budding yeast Saccharomyces cerevisiae , three enzymes for glucose phosphorylation have long been known: Hxk1, Hxk2, and Glk1. In this study, we focus on Emi2, a previously uncharacterized hexokinase-like protein of S. cerevisiae . Our data show that the recombinant Emi2 protein (rEmi2), expressed in Escherichia coli , possesses glucose-phosphorylating activity in the presence of ATP and Mg ²⁺ . It was also found that rEmi2 phosphorylates not only glucose but also fructose, mannose and glucosamine in vitro . In addition, we examined changes in the level of endogenous Emi2 protein in S. cerevisiae in the presence or absence of glucose and a non-fermentable carbon source. We found that the expression of Emi2 protein is tightly suppressed during proliferation in high glucose, while it is strongly upregulated in response to glucose limitation and the presence of a non-fermentable carbon source. Our data suggest that the expression of the endogenous Emi2 protein in S. cerevisiae is regulated under the control of Hxk2 in response to glucose availability in the environment.     

Gas Effusion Spectra of Fullerenes

Gas effusion spectra of fullerenes are studied. Three peaks of toluene are found in gas effusion spectra dp/dT-T. Two peaks of oxygen are found in gas effusion spectra dN/dt-T of samples kept in the air after annealing to avoid the toluene. These phenomena confirmed to be reversible are discussed by treating fullerenes as intercalated materials.     

Effects of Surface Concentration on Drying Behavior of Carbohydrate Solutions

As the surface properties of the drying materials are very important not only for the drying rate but also for the quality change during drying, the effects of surface concentration on the drying behavior of liquid foods (sugar solutions) were investigated by isothermal drying experiments and by numerical calculation experiments. The isothermal drying experiments with gelled sugar solution systems (sucrose and maltodextrin) were carried out at various relative humidity (RH) values (RH = 0 to 84%). Separate experiments were carried out for determination of the desorption isotherms.

The isothermal drying curves of sugar solutions at RH = 0 to 51% were very similar. Numerical simulations also showed that the drying curves of these sugars at the surface concentration = 0 and 0.1 are almost the same, although the concentration distributions are different.

When a small amount of gelatin was added to sugar solutions, the drying rate decreased remarkably as the gelatin might form a thin film (skin) near the surface, and consequently the retention of ethanol increased.     

Cortical blood flow response to hypercapnia during anaesthesia in Moyamoya disease

Cortical blood flow (CoBF) was measured continuously by the laser-Doppler method to evaluate the effect of hypercapnia on cortical blood flow during ten surgical procedures in ten young patients (mean +/- SD 9.3 +/- 6.4 yr) with Moyamoya disease. The CoBF was 42.8 +/- 13.4 (ml.100 g-1.min-1) during normocapnia (PaCO2 = 39.0 +/- 2.4 mmHg), and 38.7 +/- 14.4 during hypercapnia (PaCO2 = 47.1 +/- 2.5 mmHg). There was a decrease in CoBF with hypercapnia (P < 0.05) so that the normal CoBF response to hypercapnia was impaired during surgery in the patients with Moyamoya disease. He concluded that patients with Moyamoya disease have a precarious cerebral circulation and hypercapnia may be detrimental to the cortical circulation. This suggests that normocapnia is preferable to hypercapnia in patients with Moyamoya disease during anaesthesia.     

Successive pattern classification based on test feature classifier and its application to defect image classification

A novel successive learning algorithm based on a Test Feature Classifier is proposed for efficient handling of sequentially provided training data. The fundamental characteristics of the successive learning are considered. In the learning, after recognition of a set of unknown data by a classifier, they are fed into the classifier in order to obtain a modified performance. An efficient algorithm is proposed for the incremental definition of prime tests which are irreducible combinations of features and capable of classifying training patterns into correct classes. Four strategies for addition of training patterns are investigated with respect to their precision and performance using real pattern data. A real-world problem of classification of defects on wafer images has been dealt with by the proposed classifier, obtaining excellent performance even through efficient addition strategies.     

High Gd Concentration GaGdN Grown at Low Temperatures

GaGdN layers were grown at temperatures below 300°C by radio-frequency plasma-assisted molecular beam epitaxy on sapphire substrates. GaGdN samples with high Gd concentration as high as 12.5% were obtained by lowering the growth temperature. X-ray diffraction results showed no obvious secondary phase, which means that the phase separation can be suppressed by the growth at low temperatures. All samples, including those grown at room temperature, showed ferromagnetic characteristics. Photoluminescence emission was observed, though spectra exhibit broad and sharp luminescence bands related to many kinds of defects. It is suggested that electrons coming from defects, especially, nitrogen vacancy, stabilize ferromagnetism, and that the carrier-induced ferromagnetism occurs in the low-temperature-growth GaGdN.     

Calciothermic reduction of titanium oxide in molten CaCl<Subscript>2</Subscript>

Titanium oxides were reduced to metallic titanium using the liquid calcium floating on the molten CaCl₂. A part of Ca dissolved into CaCl₂ and reacted with TiO₂ settled below CaCl₂. The by-product CaO also dissolved by about 20 mol pct into CaCl₂, which was effective in reducing the oxygen concentration in the obtained Ti particles. The compositional region in the Ca-CaCl₂-CaO system was examined for the less oxygen contamination in Ti and the better handling in leaching. A large amount of the residual calcium oxidized the titanium powder in leaching. The metallic Ti powder less than 1000 mass ppm oxygen could be obtained only for 3.6 ks using 5 to 7 mol pct Ca-CaCl₂ at 1173 K. The powder was slightly sintered like sponge, and contained approximately 1500 ppm Ca. The anatase phae, the intermediate product in the refining process of TiO₂, could be also supplied as raw material as well as rutile.     

Zero and first sound velocity and Fermi liquid parameterF 2 s in normal3He

A precise velocity measurement of zero and first sound in normal³He was performed over the pressure range of 0.5 bar and 10 bar at a frequency of 389.1 MHz using a phase detection technique. From these measurements, the Fermi liquid parameter F ₂ ^s was determined as a function of pressure. The new value of F ₂ ^s was positive and less than 0.25 at all pressures below 10 bar. It allows propagation of transverse zero sound mode for all pressures within the current theoretical picture.     

Effects of glucose load on brain extracellular lactate concentration in conscious rats using a microdialysis technique

Changes in the brain lactate concentration in cerebral extracellular fluid (ECF) during intravenous infusion of glucose and local administration of glucose were investigated in adult, conscious, unrestrained rats, with a microdialysis probe in the posterior hippocampus. The rats were infused intravenously with either 25% sucrose solution or 25% glucose solution at a rate of 16.6 microliters.min-1.100 g-1 for three hours. The blood glucose concentration reached 17.0 +/- 2.6 mM at the end of the glucose infusion, and brain ECF glucose showed a parallel change with the blood glucose concentration and increased to 2.37 +/- 0.30 mM. However, blood and brain ECF glucose concentrations did not change in animals infused with the sucrose solution. On the other hand, the blood lactate concentration in the glucose-infused group also increased from 0.93 +/- 0.18 mM to 2.85 +/- 0.39 mM at the end of the glucose infusion, which was significantly higher than that measured in the sucrose-infused group. The blood lactate level in the glucose-infused group returned to the basal level by the end of the experiment. Brain ECF lactate concentrations increased from 1.21 +/- 0.06 mM to 1.69 +/- 0.11 mM in glucose-infused animals, but did not change in the sucrose-infused animals. The brain ECF lactate concentration showed a positive correlation with the brain ECF glucose concentration in glucose-infused animals. Another group of rats was administered glucose locally for 90 min after substitution of artificial cerebrospinal fluid.(ABSTRACT TRUNCATED AT 250 WORDS)