The muntjak satellite IA sequence is composed of 31-base-pair internal repeats that are highly homologous to the 31-base-pair subrepeats of the bovine satellite 1.715

The nucleotide sequence of a cloned Muntjak satellite IA repeat unit (Muntiacus muntjak vaginalis) was determined. The repeat is 807 base pairs (bp) long. By introducing minor deletions and insertions, the whole sequence of the satellite can be arranged in 27 subrepeats of 31 bp length. Although diverged relative to each other, all subrepeats show a homology of more than 53% with the common consensus sequence. In 29 out of the 31 bp the consensus sequence of the Muntjak satellite subrepeat is identical to the 31-bp subrepeat of the bovine satellite 1.715. This suggests that both satellites are derived from a common ancestral sequence. The results have interesting implications for the evolution of the two satellites.     

Silencing of the Y-chromosomal gene tspy during murine evolution

We have studied the process of tspy gene silencing in murine evolution. We have isolated functional tspy sequences from Apodemus agrarius, A. sylvaticus, A. flavicollis, and Mus platythrix (subgenus Pyromys) and nonfunctional tspy sequences from species of the subgenus Mus. We present two alternative models as to how tspy may have lost its function in the murine lineage. Received: 23 April 1999 / Accepted: 13 December 1999     

Thermodynamic study of β-galactosidase for high pressure separation processes

Summary The reaction of β-galactosidase with o-nitrophenyl-\-D-galactopyranoside was studied as a function of pressure and temperature. The observed activation volume was strongly dependent on the temperature. The calculation of the Maxwell relationships as well as the extrapolation of the pressure dependence f the In V_o versus pressure curves show that the system is thermodynamically consistent.     

Identification of pigment cells during early amphibian development (Triturus alpestris,Ambystoma mexicanum)

Summary The purpose of the present investigation was to provide and apply a methodological manual with which the distribution, patterning and relationship of melanophores and xanthophores can be analyzed during early amphibian development. For demonstration of the methods, which include ultrastructural, histochemical and biochemical approaches, Triturus alpestris and Ambystoma mexicanum (axolotl) embryos are used. These two species differ conspicuously in their larval pigment patterns, showing alternating melanophore bands in horizontal (T. alpestris) and vertical (axolotl) arrangements. With transmission- and scanning electron microscopy melanophores and xanthophores were distinguished by their different pigment organelles and surface structures. The presence of phenol oxidase (tyrosinase) was used to reveal externally invisible or faintly visible melanophores by applying an excess of 3,4 dihydroxy-phenylalanine (dopa). Xanthophores were made visible in fixed and living embryos by demonstrating their pterin fluorescence. In addition, pterins were analyzed by HPLC in embryos before and after pigmentation was visible.Abbreviations DOPA dihydroxy-phenylalanine - FCS fetal calf serum - FIF formaldehyde-induced fluorescence - FITC fluorescein isothiocyanate - HPLC high performance liquid chromatography Dedicated to the memory of Dr. Michael Claviez     

Glyceraldehyde-3-Phosphate Dehydrogenases from Archaea: Objects for Studying Protein Thermoadaptation

Functional and structural properties of the glyceraldehyde-3-phosphate dehydrogenases from the mesophilic archaeum Methanobacterium bryantii and from the hyperthermophilic archaea Methan-othermus fervidus, Pyrococcus woesei and Thermoproteus tenax were compared to characterize the thermophilic phenotype. Site dierected mutagenesis with the M. fervidus enzyme were performed to analyse the structural background of the thermoadaptive features of the archaeal glyceraldehyde-3-phosphate dehydrogenase.     

Estrogen-induced transformation of somatotrophs into mammotrophs in the rat

Summary In the normal male rat pituitary tritiated thymidine labeled mainly STH cells (somatotrophs), no labeled prolactin cell was found. Following estradiol treatment for 21 days tritiated thymidine labeled mainly prolactin cells (mammotrophs). To determine the origin of these mammotrophs tritiated thymidine was given before the estradiol treatment started, thus labeling many somatotrophs. After 21 days of estradiol, out of 42 labeled cells, 14 were mammotrophs and 13 were somatotrophs; these results suggest that there might be a true transformation of somatotrophs into mammotrophs under the influence of estradiol or that there exist two types of somatotrophs: 1) a committed somatotroph which is not transformed by estrogen treatment, and 2) an uncommitted mammosomatotroph, which under normal conditions bears the features of a somatotroph, but which transforms into a mammotroph under the influence of estradiol.This work was supported by grants MA-552 and MT-2701 from the Medical Research Council of Canada. The authors wish to thank Dr. G. M. Brown, Clarke Institute of Psychiatry, University of Toronto, for the radioimmunoassays of growth hormone and prolactin. Reagents for both radioimmunoassays were kindly provided by the National Institute of Arthritis and Metabolic Diseases, through the Rat Pituitary Hormone Distribution Program. — We are also thankful to Dr. L. Endrenyi, Department of Pharmacology, University of Toronto, for the statistical analysis of our data.Fellow of the Medical Research Council of Canada.     

A new species ofCrepidotus (Crepidotaceae)

Crepidotus ehrendorferi spec. nova (sect.Sphaerula) is similar to the North AmericanC. sinuosus and differs mainly by the anatomy of pileicutis with unseptated, long, slender terminal hyphae and some macroscopical characters. It is compared also withC. applanatus andC. crocophyllus. C. ehrendorferi is a very conspicuous, wood-inhabiting species known up to now from a very old forest reserve close to the city of Vienna (Austria).