Comparative behaviour of yeast strains for ethanolic fermentation of culled apple juice

The culled apple juice contained (% w/v): nitrogen, 0.036; total sugars, 11.6 and was of pH 3.9. Saccharomyces cerevisiae NCIM 3284, Pichia kluyeri and Candida krusei produced more ethanol from culled apple juice at its optimum initial pH 4.5, whereas S. cerevisiae NCIM 3316 did so at pH 5.0. An increase in sugar concentration of apple juice from natural 11.6% to 20% exhibited enhanced ethanol production and improved fermentation efficiency of both the S. cerevisiae strains, whereas P. kluyveri and C. krusei produced high ethanol at 11.6% and 16.0% sugar levels, respectively. Urea was stimulatory for ethanol production as well as fermentation efficiency of the yeast strains under study.     

Isotopic analysis of the reaction catalyzed by glycerol dehydrogenase

Glycerol dehydrogenase catalyzes the reversible NAD(+)-dependent oxidation of glycerol to form dihydroxyacetone. Initial velocity, product, and dead-end inhibition studies performed for the forward and reverse reactions support an ordered kinetic mechanism with NAD+ binding first and NADH released last. A monovalent cation is required for enzymatic activity and glycerol binding, with K+ having the highest activity as measured by V. The pH dependence of the kinetic parameters V and V/Kglycerol, as well as the temperature dependence of the V pH profile, suggested that an enzymic carboxylate group functions as a base in catalysis. The pH dependence of the primary deuterium kinetic isotope effect shows that DV/Kglycerol increases from a pH-independent value of 1.15 at high pH values to a pH-independent value of 2.44 at low pH values. DV exhibits a similar pH dependence, increasing from a pH-independent value of 2.57 at high pH values to a pH independent value of 4.88 at low pH values. A chemical mechanism for enzymatic glycerol oxidation is proposed based on the data.     

Expression of glycosylated and nonglycosylated human transferrin in mammalian cells. Characterization of the recombinant proteins with comparison to three commercially available transferrins

The coding sequence for human serum transferrin was assembled from restriction fragments derived from a full-length cDNA clone isolated from a human liver cDNA library. The assembled clone was inserted into the expression vector pNUT and stably transfected into transformed baby hamster kidney (BHK) cells, leading to secretion of up to 125 mg/L recombinant protein into the tissue culture medium. As judged by mobility on NaDodSO4-PAGE, immunoreactivity, spectral properties (indicative of correct folding and iron binding), and the ability to bind to receptors on a human cell line, initial studies showed that the recombinant transferrin, is identical to three commercial human serum transferrin samples. Electrospray mass spectrometry (ESMS), anion-exchange chromatography, and urea gel analysis showed that the recombinant protein has an extremely complex carbohydrate pattern with 16 separate masses ranging from 78,833 to 80,802 daltons. Mutation of the two asparagine carbohydrate linkage sites to aspartic acid residues led to the expression and secretion of up to 25 mg/L nonglycosylated transferrin. ESMS, anion-exchange chromatography, and urea gel analysis showed a single molecular species that was consistent with the expected theoretical mass of 75,143 daltons. In equilibrium binding experiments, the nonglycosylated mutant bound to HeLa S3 cells with the same avidity and to the same extent as the glycosylated protein and the three commercial samples. These studies demonstrate conclusively that carbohydrate has no role in this function.     

Reversal of chloroquine resistance in murine malaria parasites by prostaglandin derivatives

An oligomeric ester of prostaglandin B2 (OC-5186) was found to reverse chloroquine resistance in the murine malarial parasite Plasmodium berghei. When mice were infected with either chloroquine-sensitive or -resistant P. berghei on day 0 (by intraperitoneal injection of 1 x 10(6) parasitized erythrocytes), they died before day 23. When treated with 15 mg/kg/day of chloroquine for the first four days of infection, all mice infected with the sensitive-strain survived, while all those infected with the resistant strain died before day 23. When OC-5186 (3-12 mg/kg/day) was administered in combination with chloroquine for the first four days, 60% of the animals infected with the resistant strain survived. The differences in the survival rate between the group treated with chloroquine only and the group treated with a combination of drugs (chloroquine plus 3-12 mg/kg/day of OC-5186) were significant. There was also a significant inhibition of parasitemia in the group treated with the combination of drugs. The combinations of chloroquine and a monomer ester of prostaglandin B2 (OC-5181) had some antimalarial activity, but the differences between the chloroquine-treated group and the combination treatment group were not significant in terms of both the parasitemia and the survival rate. Another oligomeric ester of prostaglandin E1 (MR-356) as well as unesterified monomer prostaglandins (PGA2 and PGB2) were ineffective by themselves and in combination with chloroquine.     

Experience with a Multitransducer Ultrasound System for Localized Hyperthermia of Deep Tissues

A system employing six planar ultrasound transducers has been utilized for preclinical and pilot clinical studies with the aim of producing therapeutic heating preferentially at depth. The array consists of six 7 cm diameter PZT-4 disks mounted on a spherical shell section with a 26 cm radius of curvature. The crystals operate at different frequencies a few kilohertz above their fundamental frequencies of approximately 350 kHz for near-field peak suppression, and each has a few percent modulation to minimize standing wave effects. In water, the system can be focused to produce a high intensity region near the isocenter with a full width half maximum of approximately 1.5 cm in all directions. In attenuating tissue, the high intensity region is closer to the array of transducers by a few centimeters. For heating of realistic tumors at depth, small wedges are used to rotate the transducer axes a few degrees away from the radial direction, yielding a waist rather than a single point where the individual beam central axes come closest to each other. The waist is 3-6 cm in diameter, producing, ideally, ellipsoidal shaped temperature distributions centered deep in perfused tissue. Quantitative power deposition profile mapping, as well as qualitative studies using liquid crystal sheets, have been performed in water phantoms to characterize the system for different transducer orientations.     

Inversion polymorphism in natural populations of Drosophila bipectinata

Inversion polymorphism was studied in seven natural populations of Drosophila bipectinata, five from northern and two from southern India. Chromosomal analysis of these populations revealed the presence of three paracentric inversions which are widespread in populations of D. bipectinata. Quantitative data indicated that the frequency of inversions and the level of inversion heterozygosity were very low in populations of D. bipectinata. There is no evidence for genetic differentiation between populations as a result of inversion polymorphism. These findings provide evidence for rigid chromosomal polymorphism in D. bipectinata. Significant non-random associations between inversions indicated epistatic interaction between inversions in natural populations of D. bipectinata.     

Partially glucose-capped oligosaccharides are found on the hemoglobins of the deep-sea tube worm Riftia pachyptila

We report here the structural determination of N-linked oligosaccharides found on extracellular hemoglobins of the hydrothermal vent tube worm Riftia pachyptila. Structures were elucidated by a combination of electrospray ionization tandem mass spectrometry, matrix-assisted laser desorption/ionization mass spectrometry, normal-phase high performance liquid chromatography, and exoglycosidase digestion. The sugar chains were found to consist mainly of high-mannose-type glycans with some structures partially capped by one or two terminal glucose residues. The present study represents the first report of the occurrence of glucose capping of N-linked carbohydrates in a secreted glycoprotein of a metazoan. Previously, glucose capping has only been described for a membrane-bound surface glycoprotein from the unicellular parasite Leishmania mexicana amazonensis.     

A trial of the long-term use of Sedacorone (amiodarone) under polyclinic conditions for the prevention of paroxysms of atrial fibrillation

Sedacorone (amiodarone) was given to 70 outpatients with coronary heart disease for 1.5-2 years to prevent paroxysms of cardiac arrhythmia after recovery of sinus rhythm. Sedacorone was administered initially in the dose 600 mg/day for 10-12 days, then the dose lowering was adjusted to the tolerance, heart rate and ECG readings. The minimal dose of 200 mg/day was taken for 5 days a week with a 2-day interval. In adequate individual dose Sedacorone prevented paroxysms of cardiac fibrillation or made the paroxysms less frequent in 91.4% of patients. Careful selection of patients and regular control helped avoid serious cardial and extracardiac complications. Sedacorone is recommended as a first-line medicine for outpatients with frequent paroxysms of cardiac fibrillations after recovery of the sinus rhythm to prevent the paroxysms recurrences.