Continuous coenzyme dependent stereoselective synthesis of sulcatol by alcohol dehydrogenase

Summary 6-methyl-5-hepten-2-one was reduced to sulcatol ((+)-6-methyl-5-hepten-2-ol) by using alcohol dehydrogenase fromThermoanaerobium brockii in a continuous process. The cofactor NADP(H) was retained by a charged UF-membrane and regenerated by oxidation of isopropanol to acetone. Use of native NADP in a charged UF-membrane reactor proved to be superior to use of PEG coupled NADP in a uncharged UF-membrane reactor.     

Concordance of mammalian ejaculate features.

Different measures of ejaculate characteristics, such as ejaculate volume, proportion of normal sperm, proportion of motile sperm, and total number of sperm per ejaculate, are directly related to the probability of fertilization both when females copulate with a single male and particularly with multiple males. Selection will therefore favour the evolution of ejaculate characteristics which enhance the probability of fertilization, and I predict positive relations between ejaculate parameters. I used a literature survey of mammalian ejaculate parameters to test this prediction. The data set was corrected for similarity between taxa which resulted from common ancestry, and was reduced to statistically independent standardized linear contrasts. The number of sperm per ejaculate and ejaculate volume were positively related to body mass, but when the confounding effect of body mass was controlled for, all four ejaculate characteristics showed positive relations, and five out of six were statistically significant. This suggests that the different measures of ejaculate quality in mammals have been improved simultaneously, apparently by a common selective force.     

Growth and pubertal development during and after treatment with a slow-release gonadotropin-releasing hormone agonist in central precocious puberty.

The auxological data of 25 patients (21 girls, 4 boys) with central precocious puberty (CPP), treated for 4 years with a slow-release gonadotropin-releasing hormone agonist [Decapeptyl-controlled release (D-CR) 3.75] every 4 weeks intramuscularly, and of 6 patients (3 girls, 3 boys), treated for 5 years, are presented. After 3 years of D-CR a stabilization of height velocity (HV) at about 4 cm/year was observed. Bone maturation (ratio of change in bone age to change in chronological age; delta BA/delta CA) slowed down to a mean delta BA/delta CA ratio of 0.5 +/- 0.2 (mean +/- SD) measured over 48 months. As a result, predicted adult height (PAH) improved from 156.3 +/- 7.4 to 162.2 +/- 6.8 cm in girls (p less than 0.001) and from 174.4 +/- 18.6 to 184.3 +/- 17.1 cm in boys after 4 years. In the 5th year an ongoing improvement of PAH was observed. 20 additional girls discontinued D-CR for at least 12 months after treatment with D-CR for 2 years or more. In 11 girls menses started after 10.6 +/- 3.1 months; 9 girls had no menarche after 12-16 months. HV increased in the first and second 6 months to a level of about 6.0 cm/year, decreased in the third 6 months after cessation to the level before discontinuing D-CR and decreased further afterwards. Bone maturation (delta BA/delta CA) increased progressively in the first 18 months after discontinuation, with a stabilization at about 1.3. PAH did not change in the first 12 months after discontinuation of D-CR, but showed a decrease afterwards.(ABSTRACT TRUNCATED AT 250 WORDS)     

Biotransformation of 2,2-Dimethyl-1,3-Propanediol to 3-Hydroxypivalic Acid by Acetobacter Acetii DSMZ3508 and Related Bacteria

Acetobacter acetii DSMZ3508 and related bacteria converted 2,2-dimethyl-1,3-propanediol into 3-hydroxypivalic acid (2,2-dimethyl-3-hydroxypropionic acid; 3HP) during submerged cultivation in mineral salt medium. The maximum yield of 3-hydroxypivalic acid was 24.4% of the fed substrate after 18 days. Cultivation parameters, as pH, cell density, optimal substrate concentration, and oxygen supply for the bioconversion process were determined.     

Oat mesophyll protoplasts: their response to various feeder cultures

Oat (Avena sativa L.) mesophyll protoplasts were recently demonstrated to be capable of dedifferentiation, repeated divisions, and colony formation. Since the development of oat mesophyll protoplasts is decisively influenced by the nature of the used feeder culture (species, variety and concentration), we conducted a systematic study of this parameter. Generally, graminaceous feeders promoted protoplast proliferation, while dicot species repressed protoplast divisions. The beneficial effect of those feeders that promote divisions was counterbalanced by a factor that causes necrosis. The correct balance between promotion of divisions or necrosis depended on the nature of the feeder and its plating density.     

Dynamic and steady state characteristics of the rabbit gastrocnemius muscle determined in series measurements

1. Within the range of the given conditions of measuring static and dynamic properties of the rabbit gastrocnemius muscle the following results were obtained: a) the dependence of the maxima of isotonic shortening upon the relative length of the muscle at constant load is linear; b) the parameters of the non-linear dependence of the passive elastic force of the muscle upon its relative length (measured in series) were identified using asymptotic regression; c) the time course of isotonic contractions (at an interval from 0 to 0.3 s after the beginning of stimulation) could be satisfactorily approximated by responses of a linear system to a step-function; d) the time course of isometric contractions (at an interval from 0 to 0.3 s after the beginning of stimulation) could be closely approximated by responses of a linear system to a step-function. 2. The time constants of isotonic and isometric contractions were determined as the parameters of the corresponding linear systems. 3. The maximum rates of the isometric and isotonic contractions were determined as maxima of the first derivatives of the responses of the corresponding models. 4. The experimental set-up made it possible to compare the values of the parameters concomitantly followed at various muscle lengths and at various loads.     

Influence of nitrate and nitrite on electrolyte transport by the rat small and large intestine

1. The influence of nitrate and nitrite on net absorption of electrolytes (Na+, K+, Cl-) and water from ligated loops was studied at various intestinal sites in rats. 2. Nitrate strikingly reduced Cl- absorption in rat proximal and distal colon, whereas Na+ absorption was reduced only moderately. Nitrite also reduced Cl- absorption in the colon. 3. Nitrate showed no significant effect on electrolyte absorption in the small intestine. 4. The results suggest that Cl-/HCO3- on exchange is the major route of Cl- absorption in the colon, whereas this mechanism seems not to be of importance for Cl- absorption by the small intestine.     

The effect of increasing glucose in CPD on the quality of stored blood

Changes in quality of blood units containing one and a half or double amounts of glucose, stored at +4 degrees C for three weeks were analysed. An experimental preservative containing glucose and fructose (1 : 1) was also used. No other additives (purine or purine-nucleoside) were applied. A standard CPD preservative of the National Inst. of Haematology and Blood Transfusion was used as control. The pH, plasma free haemoglobin, K+ content, red blood cell (RBC) ATP and 2,3-DPG content, and RBC fragility index were determined in each sample. Increase of glucose concentration, the addition of fructose had a beneficial effect on blood pH, and on plasma free haemoglobin and K+ concentration. 150% glucose improved the 2,3-DPG maintenance in stored blood.