Showing papers by "Martin Luther University of Halle-Wittenberg published in 1994"

The protein encoded by the Drosophila position-effect variegation suppressor gene Su(var)3-9 combines domains of antagonistic regulators of homeotic gene complexes.

Abstract: Modifier mutations of position-effect variegation (PEV) represent a useful tool for a genetic and molecular dissection of genes connected with chromatin regulation in Drosophila The Su(var)3-9 gene belongs to the group of haplo suppressor loci which manifest a triplo enhancer effect Mutations show a strong suppressor effect even in the presence of PEV enhancer mutations, indicating a central role of this gene in the regulation of PEV By molecular analysis, Su(var)3-9 could be correlated with a 24 kb transcript which encodes a putative protein of 635 amino acids containing a chromo domain and a region of homology to Enhancer of zeste and trithorax, two antagonistic regulators of the Antennapedia and Bithorax gene complexes, as well as to the human protein ALL-1/Hrx which is implicated in acute leukemias This region of homology is found in all four proteins at the C-terminus The homology of Su(var)3-9 to both negative (Polycomb and Enhancer of zeste) and positive (trithorax) regulators of the Antennapedia and Bithorax complexes also suggests similarities in the molecular processes connected with stable transmission of a determined state and the clonal propagation of heterochromatinization

Skin test reactivity and number of siblings.

Abstract: Objective: To investigate the relation between skin test reactivity in children and number of siblings. Design: Cross sectional survey among school-children aged 9-11 years. Skin prick tests in the children and self completion of written questionnaire by their parents. Subjects: 5030 children in Munich and 2623 children in Leipzig and Halle, Germany. Main outcome measures: Atopic status assessed by skin prick tests. Results: After possible confounders were controlled for, the prevalence of atopic sensitisation decreased linearly with increasing number of siblings (odds ratio=0.96 for one sibling, 0.67 for five or more siblings; P=0.005). In atopic children the severity of the skin test reaction as assessed by the weal size was not associated with the number of siblings. Conclusions: Factors directly or indirectly related to the number of siblings may decrease the susceptibility of children to become atopic. Thus, declining family size may in part contribute to the increased prevalence of atopic diseases reported in Western countries over the past few decades.

The Trithorax-like gene encodes the Drosophila GAGA factor

Abstract: LITTLE is known about the way higher-order chromatin structure influences gene expression and chromosome topology in general. Genetic analysis in Drosophila has led to the discovery of two classes of genes, the regulators of homeotic genes and the modifiers of position-effect variegation, which seem to be good candidates for encoding some of the factors regulating chromatin functions1,2. The Trithorax-like gene we describe here is required for the normal expression of the homeotic genes and is a modifier of position-effect variegation. We found that Trithorax-like encodes the GAGA factor which is involved in the formation of an accessible chromatin structure at promoter sequences3. Our genetic analysis suggests that the chromatin modelling function of the GAGA factor is not restricted to promoter regions.

Abdominal CSF pseudocysts in patients with ventriculo-peritoneal shunts. Report of fourteen cases and review of the literature

Abstract: The abdominal intraperitoneal cerebrospinal fluid pseudocyst is an infrequent but important complication in patients with ventriculoperitoneal shunts. Since 1954, 115 cases of paediatric pseudocysts have been reported in the literature. One additional report deals with an adult patient.

Prototype breast coil for MR-guided needle localization.

Abstract: OBJECTIVE Evaluation of breast lesions detected by MR alone is a problem: Preoperative MR-guided localization is difficult, since the breast is not accessible by a needle within the breast coil. Magnetic resonance-guided core biopsy and needle aspiration are impossible. Together with Siemens Erlangen, a prototype localization breast coil has been developed and tested. MATERIALS AND METHODS The device consists of a circular polarized coil, which contains two plates for mediolateral breast compression. They are perforated with numerous holes and thus allow access to the breast from both sides. By means of bushings, which fit into the holes, sterile needle insertion in a horizontal path is possible. RESULTS So far, precise needle insertion has been possible in 10 of 11 lesions, allowing exact needle insertion into 5 invasive carcinomas (1 MR-detected), 1 MR-detected additional focus, 2 in situ carcinomas (1 MR-detected), and 3 benign lesions. CONCLUSION Our studies show that MR-guided needle localization is possible.

Glycine metabolism in anaerobes

Abstract: Some strict anaerobic bacteria catalyze with glycine as substrate an internal Stickland reaction by which glycine serves as electron donor being oxidized by glycine-cleavage system or as electron acceptor being reduced by glycine reductase In both cases, energy is conserved by substrate level phosphorylation Except for the different substrate-activating proteins PB, reduction of sarcosine or betaine to acetyl phosphate involves in Eubacterium acidaminophilum the same set of proteins as observed for glycine, eg a unique thioredoxin system as electron donor and an acetyl phosphate-forming protein PC interacting with the intermediarily formed Secarboxymethylselenoether bound to protein PA

[34] Cathepsin S and related lysosomal endopeptidases

Abstract: Publisher Summary This chapter highlights cathepsin S and related lysosomal endopeptidases. Cathepsin S is a cysteine proteinase purified from bovine lymph nodes. By using the most susceptible substrates, such as Bz-Phe-Val-Arg-NHMec or Z-Val-Val-Arg-NHMec (pH 7.5), the specific determination of cathepsin S is possible. The substrate Z-Val-Val-Arg-NHMec is hydrolyzed to liberate 7-amino-4-methylcoumarin, which is quantified continuously by its intense fluorescence or in stopped assays after the termination of the enzymatic reaction by monochloroacetate. The fluorescence of the free aminomethylcoumarin is determined by excitation at 360 nm and emission at 460 nm. Cathepsin S can be stored in 0.1 M sodium acetate buffer containing 1 mM disodium ethylenediaminetetraacetic acid (EDTA), pH 5.5, at –20°. Mature active cathepsin S is a single-chain polypeptide comprising 217 amino acid residues. Cathepsin S is active toward proteins and synthetic peptide substrates over the range of pH 5.0 to 8.0. Cathepsin S has the unique property among the lysosomal cysteine proteinases of degrading soluble proteins and insoluble elastin at acid and neutral pH values.

Contrast-enhanced MR imaging of the breast: comparison of two different doses of gadopentetate dimeglumine.

Abstract: PURPOSE: To optimize detection and diagnosis of breast lesions with contrast-enhanced magnetic resonance (MR) imaging MATERIALS AND METHODS: A three-dimensional fast low-angle shot pulse sequence was used for a group comparison consisting of 76 high-dose (016 mmol gadopentetate dimeglumine per kilogram of body weight) and 76 low-dose (01 mmol/kg) examinations Intraindividual comparisons were possible in a subgroup of 20 patients RESULTS: Enhancement with the high dose was about 15 times higher for benign and malignant tissues With the lower dose, no false-positive findings could be avoided and definition of a threshold that excluded false-negative findings was problematic Conspicuity of malignant lesions was much improved with the higher dose (a good to excellent rating in 81% vs 26% with the lower dose) Three small foci were visible only with the higher dose CONCLUSION: The higher dose of contrast material allowed much better results Dose comparison studies are also recommended for other techn

Expression of Polarity during early Development of Microspore‐derived and Zygotic Embryos of Brassica napus L. cv. Topas

Abstract: Microspore derived (MS-)embryogenesis and zygotic embryogenesis of Brassica napus L. cv. Topas were investigated by light and scanning electron microscopy to reveal the expression of polarity during the transition phase from globular to heart and torpedo shape. During the first 5 days of MS-embryo formation, the cell wall of the former microspores remained intact and a globular mass of cells developed within. Pollen walls ruptured after 5 days of culture; embryos proceeded through heart-shape and torpedo-shape stages within 15 days in a way comparable to, but faster than observed during zygotic embryogenesis. Expression of polarity in globular and elongating MS-embryos was analyzed by detection of the distribution of activated calmodulin as well as of free cytosolic calcium by using confocal scanning laser microscopy, and by the detection of starch. Calmodulin was evenly distributed in globular embryos and only exhibited clear polar distribution in elongated embryos. Free cytosolic Ca2+ accumulated in the protoderm of globular embryos and in the central cylinder of torpedo shaped embryos, but never showed polar distribution. Accumulation of starch granules at the root poles of both sexual as well as MS-embryos, however, indicated polar distribution before the transition from globular to heart shape stage. Since the local rupture of the pollen wall of 6-day-old MS-embryos was never preceded by the decrease of starch at that site, it is likely that the rupture of the pollen wall plays an important role in the local activation of cell metabolism and thus in the determination of the polarity axis in MS-embryos.

Bis(benzo[4,5]thieno)[3,2‐c:2′,3′‐e][1,2]dithiin, ein Valenzisomer von „Dithioxo‐thioindigo”︁

Abstract: Bis(benzo[4,5]thieno)[3,2-c:2′,3′-e][1,2]dithiin, ein Valenzisomer von „Dithioxo-thioindigo” 3-Mercaptobenzo[b]thiophene (1) is transformed with assistance of bases, especially of amines, into the benzo[b]-thieno-annellated 1,2-dithiine 6 and not into the originally claimed “Dithioxo-thioindigo” trans-3. Primarily, the formation of 6 from 1 involves oxidation to the disulfide 4 which may also be used separately. Conceivable rationalizations are discussed. The same compound is accessible (in lower yield)by thionation of thioindigo with the aid of the Lawesson reagent. X-ray elucidation of 6 reveals a non-planar structure of the cyclic disulfide with a dihedral CSSC-angle of 53°. Despite of the absence of any established chromonphoric moiety, 6 is deeply red in the crystal and in solution, as it is representative for the “undisturbed” 1,2-dithiine system. Contrary to the usual behaviour of the non-annellated 1,2-dithiines, 6 displays no spontaneous sulfur extrusion under mild conditions, but only at high temperatures and in the presence of sulfur-binding agents, leading to the benzo[b]thieno-annellated thiophene 22. Moreover, 6 may be reduced to the dithiol 14 (or 13, respectively) and regenerated exclusively from this by oxidation. Further characteristic reactions of 6 are described (e.g. to the sulfoxide 18, to the pyridazine 19, and to the thiphosphoric ester 21).

Cadmium in beavers translocated from the Elbe river to the rhine/meuse estuary, and the possible effect on population growth rate

Abstract: Beavers (Castor fiber) from the Middle Elbe region were re-introduced in the Biesbosch, The Netherlands, an estuary contaminated with cadmium (Cd) by the rivers Rhine and Meuse. The Middle Elbe region was also polluted with Cd, but the beavers released in the Biesbosch originated from two relatively clean habitats within this region. The Biesbosch population grew slower than other released beaver populations in Europe, and it was hypothesized that Cd intoxication was responsible for this. The beavers fed primarily on the bark and leaves of willow and poplar trees, which contained great concentrations of Cd. The average Cd concentration in the food (6.9 μg/gdry) was above the maximum tolerable concentration for large domestic herbivores. The Cd concentrations of the kidneys and hair of the beavers were correlated with those in the bark of the trees. The Cd concentration in the hair increased threefold after the release in the Biesbosch, and the geometric mean Cd kidney concentration was 55 μg/gdry. Using three different models, an average Cd kidney concentration in the beavers of >100 μg/gdry was predicted in the Biesbosch in the near future. Such a concentration causes kidney damage in some other mammals. Beaver kidneys from the Mulde, a tributary of the Elbe, contained on average 467 μg Cd/gdry, the greatest concentration reported in herbivores. Nevertheless, the fertility along the Mulde was high, due to the fact that it is an otherwise optimal beaver habitat. Furthermore, the low fertility in the Biesbosch was due to a small fraction of successful breeding pairs. We conclude that the initial low population growth rate in the Biesbosch was probably not caused by contamination with Cd. However, future effects on the individual (reproductive) life span cannot be ruled out.

Resynchronization of the Circadian Corticosterone Rhythm After a Light/Dark Shift in Juvenile and Adult Mice

Abstract: Most of the extensive literature concerning the resynchronization of circadian rhythms after a Zeitgeber shift is devoted to the dependence of resynchronization on the mode of the shift and the strength of the Zeitgeber, as well as on the circadian function investigated. Ontogenetic influences have rarely been investigated. Therefore, we studied the resynchronization of several circadian rhythms in juvenile and adult female laboratory mice. We present here the results concerning the corticosterone rhythm. The daily rhythms were determined as transverse profiles (2-h intervals) before as well as 3, 7, and 14 days after an 8-h phase delay of the light/dark cycle produced by a single prolongation of dark time. The corticosterone concentration in serum was determined radioimmunologically. In the control animals the daily patterns were bimodal, with main maxima at the end of the light time and secondary ones just after lights on. Ontogenetic differences were small. In adult mice the amplitude was slightly incr...

Relation between persistent current and band structure of finite-width mesoscopic rings.

Abstract: The energy bands of a finite-width mesoscopic multichannel ring are calculated using the transfer-matrix method. Two approaches are developed, the diagonal approximation and the multichannel model. We apply these results to the calculation of the persistent current in mesoscopic rings enclosing the magnetic flux \ensuremath{\Phi} in the ballistic regime. It is shown that the interchannel coupling in a finite-width mesoscopic ring produces a halving of the fundamental period h/e of the persistent current ${\mathit{I}}_{\mathit{A}}^{(\mathit{n}\mathrm{\ifmmode \tilde{}\else \~{}\fi{}})}$(\ensuremath{\Phi}).

Remarks to an equivalent formulation of ekeland’s variational principle

Abstract: A recent theorem Of W.Takahashi will be pointed out as an equivalent formulation of Ekelands variational principle. This gives rise to study functions having sets of weak sharp minimas in a generalized sense. Connections to the proximal point algorithm in the convex case leads to the basic and still open question: How to use Ekelands principle numerically

The influence of N2-fixation on the carbon balance of leguminous plants

Abstract: Biological dinitrogen fixation by legume-rhizobia symbiosis is very important both from the economic and from the ecological point of view. Theoretically, the reduction of the N2-molecule to ammonia requires at least 16 ATP and 1.5 mg C per mg N fixed (Nfix). These values are difficult to determine in situ as this necessitates the determination of that part of root respiration which drives N2-fixation. New approaches to such determinations and the results obtained are described. The values vary, depending on the plant species studied, the developmental stage of the plants and the genetic variability of macro- (and micro-?) symbionts. The values range between 1.5 and 4 mg C/mg Nfix. In some species (e.g.Vicia faba L. cv. Fribo), the apparent CO2 assimilation is enhanced in order to meet this high energy need. In others (e.g.Pisum sativum L. cv. Grapis), root growth is restricted. Physiological criteria are discussed which allow an early diagnosis of the energetic efficiency of various combinations of macro-and microsymbionts as a basis for a selection in plant breeding.

Immunophenotype of lymphocytes in pericardial fluid from patients with different forms of heart disease

Abstract: Cytofluorometric analysis was performed to characterize the immunophenotype of lymphocytes of the pericardial fluid (PF) from 127 patients undergoing open cardiac operation (heart valve disease, congenital heart defects, chronic ischemic heart disease). Macrophages and T cells represented the dominant cell types. Similar to T cells of body fluids other than peripheral blood, a high percentage of PF T cells expressed CD45RO and activation-associated molecules such as HLA-DR, CD69, CD54 and CD26. Surprisingly, we could demonstrate a very high proportion of CD11b+ T cells in PF. Furthermore, a significant proportion of PFT cells expressed aminopeptidase N/CD13. PF was further analyzed for the presence of IL-6, TGF-beta as well as TNF-alpha. IL-6 levels were low (undetectable to 4,500 U/ml), TGF-beta levels ranged from < 3 ng/ml up to 80 ng/ml, and TNF-alpha levels from < 3 pg/ml to 233 pg/ml. These findings show evidence of the presence of activated lymphocytes with a special immunophenotype as well as multiple cytokines in PF of patients with different forms of heart disease.