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.     

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)     

Ants adjust their pheromone deposition to a changing environment and their probability of making errors

Animals must contend with an ever-changing environment. Social animals, especially eusocial insects such as ants and bees, rely heavily on communication for their success. However, in a changing environment, communicated information can become rapidly outdated. This is a particular problem for pheromone trail using ants, as once deposited pheromones cannot be removed. Here, we study the response of ant foragers to an environmental change. Ants were trained to one feeder location, and the feeder was then moved to a different location. We found that ants responded to an environmental change by strongly upregulating pheromone deposition immediately after experiencing the change. This may help maintain the colony''s foraging flexibility, and allow multiple food locations to be exploited simultaneously. Our treatment also caused uncertainty in the foragers, by making their memories less reliable. Ants which had made an error but eventually found the food source upregulated pheromone deposition when returning to the nest. Intriguingly, ants on their way towards the food source downregulated pheromone deposition if they were going to make an error. This may suggest that individual ants can measure the reliability of their own memories and respond appropriately.     

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.     

The oncolytic peptide LTX-315 triggers necrotic cell death

The oncolytic peptide LTX-315 has been designed for killing human cancer cells and turned out to stimulate anti-cancer immune responses when locally injected into tumors established in immunocompetent mice. Here, we investigated the question whether LTX-315 induces apoptosis or necrosis. Transmission electron microscopy or morphometric analysis of chromatin-stained tumor cells revealed that LTX-315 failed to induce apoptotic nuclear condensation and rather induced a necrotic phenotype. Accordingly, LTX-315 failed to stimulate the activation of caspase-3, and inhibition of caspases by means of Z-VAD-fmk was unable to reduce cell killing by LTX-315. In addition, 2 prominent inhibitors of regulated necrosis (necroptosis), namely, necrostatin-1 and cycosporin A, failed to reduce LTX-315-induced cell death. In conclusion, it appears that LTX-315 triggers unregulated necrosis, which may contribute to its pro-inflammatory and pro-immune effects.     

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.