Showing papers by "University of Jena published in 1993"

Evidence for Protostellar Collapse in B335

Abstract: We have observed five rotational transitions of H2CO and CS toward the Bok globule, B335, with high spatial and spectral resolution. The characteristic shape of the observed profiles provides direct, kinematic evidence of collapse. In addition, we have modeled line profiles of collapsing dense cores with density and velocity structures taken from the theory of Shu and coworkers. Using the age of collapse as the only free parameter, we found that the strengths and profiles of the observed lines can be well fitted by the theoretical model. Our best-fit model gives an age of 1.5 x 10 exp 5 yr, corresponding to an infall radius of 0.04 pc and a total mass of 0.4 solar mass for the central star and disk. Outside the infall radius, there is a static envelope with a r exp -2 density distribution, an average temperature of 13 K, and a turbulent velocity (1/e width) of 0.12 km/s. The CS abundance is 3.6 x 10 exp -9 with about 30 percent uncertainty.

Dehydration of phosphate glasses

Abstract: For several phosphate glass systems composed of K2O, SrO, (La, Nd)2O3 and P2O5, different dehydration methods have been investigated: variation of raw materials, addition of halides, sintering of raw material mixtures, remelting of glasses, variation of melting time, bubbling of dry oxygen. The methods have been compared with each other concerning their effect on decreasing the OH content. Further, a model of the interactions between glass melt and atmosphere has been established for glasses prepared using fluoride addition or not.

Metabolism of PAH by fungi and correlation with extracellular enzymatic activities

Abstract: The activity to metabolize the polycyclic aromatic hydrocarbons (PAH) phenanthrene, anthracene, pyrene, fluorene and fluoranthene by Trametes versicolor, Pleurotus ostreatus (white rot fungi), Laetiporus sulphureus, Daedaela quercina, Flamulina velutipes (brown rot fungi), Marasmiellus sp. (litter decaying fungus) and Penicillium sp. M 1 (isolated from a PAH contaminated soil sample) were compared. Screening methods for the presence of exoenzymes (peroxidases, polyphenoloxidases, "radical generating" enzymes) were evaluated for their use in screenings for fungi degrading PAH. Laetiporus sulphureus and Penicillium sp. M 1 cometabolize several PAH with rates comparable to white rot fungi. In most of the cases the patterns of extracellular peroxidases indicate the potential of fungi to degrade PAH.

Transformation of the First Zirconocene Alkyne Complex without an Additional Phosphane Ligand into a Dinuclear σ‐Alkenyl Complex by Hydrogen Transfer from η5‐C5H5 to the Alkyne Ligand

Abstract: Chaussard, J.-C. Folest, J.-Y. Nedelec, J. Perichon. S. Sibille, M. Troupel, Sj,nrhesis 1990, 369-381. [ l 11 K.-H. Schwarz, K. Kleiner, R. Ludwig. H. Schick, J . Org. Chem. 1992.57, 401 3 -401 5 . [12] T. Moriwake. J . Org. Chem. 1966. 31, 983-985. 1131 E. Burkhardt, R. D. Rieke. ./. Org. Chem. 1985, 50. 416-417. [14] S. N. Inaba, R. D. Rieke. Tetrahedron Lett. 1985, 26, 155-156. [15] T. Imamoto, T. Kusumoto, Y. Tawdrayamd. Y. Sugiura, T. Mita. Y. Hatanaka. M . Yokoyama. J Org. Chem. 1984, 49. 3904-3912. [16] G. Cahier, P:Y Chavdnt. Teiruhedron Lett. 1989, 30, 7373-7376. [17] L -C. Chao. R. D. Rieke, J. Org. Chem. 1975,40, 2253-2255. [18] S. Ardki. H. Ito. Y Butsugdn, Synth. Commun. 1988, 18, 453-458. [I91 P. S. Johdr. S. Ardki. Y. Butsugan, J. Chem. SOC. Perkin Trans. 1992,

Multiple binding of type 3 streptococcal M protein to human fibrinogen, albumin and fibronectin

Abstract: M proteins are major virulence factors of group A streptococci which enable the bacteria to resist phagocytic attack. Their binding capacity for different plasma proteins seems to be one reason for the antiphagocytic activity of M protein. In the present study we demonstrate that M3 protein, isolated from the streptococcal culture supernatant of strain 4/55, and the recombinant form (rM3), purified from an E. coli lysate after cloning in phage γ-EMBL3, show a multiple binding to fibrinogen, albumin and fibronectin in Western blot and dot binding assays. Binding of M3 protein to the multifunctional extracellular matrix and plasma protein fibronectin may not only influence phagocytosis but may also contribute to the adherence of these bacteria to endothelial and epithelial cells.

Aging, training and exercise : a review of effects on plasma glutathione and lipid peroxides

Abstract: Changes in plasma glutathione (reduced form: GSH; oxidised form: GSSG) and lipid peroxides (LPO) levels occur with aging, training and acute physical exercise. Sources of plasma GSH, GSSG and LPO include the liver and skeletal muscle. Aging appears to be accelerated because of a decrease in the antioxidant capacity of tissues reflected in a decreased plasma GSH level. This age-dependent change could be partly compensated by physical training. Skeletal muscle appears to be able to deliver GSH into circulation with the adaptation of muscle to exercise training reflected in an increased plasma GSH level in the trained subject. Decreased plasma GSH concentration following physical exercise demonstrates increased GSH consumption in skeletal muscle resulting in a reduced export rate from muscle into plasma. The GSH system is able to effectively protect tissues against lipid peroxidation initiated by oxygen-derived free radicals produced in the intermediate metabolism during exercise. It can be assumed that the rate of this free radical production is a function of oxygen flow through organ and muscle tissue.

On a BPX-preconditioner for P1 elements

Abstract: We derive an optimal multilevel preconditioner for nonconforming P1 element discretizations of second order elliptic boundary value problems.

Functional aspects of secondary carotenoids in Haematococcus lacustris [Girod] Rostafinski (Volvocales) IV. Protection from photodynamic damage

Abstract: The function as an antioxidant seems to represent the central principle of chemopreventive activity of carotenoids against cancer initiation and promotion. The aim of this study was to clarify whether or not extrachloroplastic-accumulated secondary carotenoids (astaxanthin, canthaxanthin and echinenone) of Haematococcus lacustris [Girod] Rostafinski exhibit a similar antioxidative activity in protecting the cell of this green alga from photo-oxidative damage. In vivo experiments were performed, investigating the effect of UV radiation, artificial photosensitizers (rose bengal, toluidine blue) and copper-mediated lipid peroxidation on suspensions of flagellates which contained different amounts of secondary carotenoids. The results revealed a higher resistance of red flagellates to photo-oxidative stress. The findings are discussed with respect to the shading function of secondary carotenoids and known protective mechanisms involving quenching of reactive oxygen species and radical reactions in plant cells. A hypothesis for this functional aspect of secondary carotenoids in H. lacustris preventing injury by excessive insolation is suggested: ketocarotenoids, first accumulated in lipid vacuoles around the nucleus, might act as a physico chemical barrier, protecting particularly the genome from free radical-mediated damage.

Exact analytical formulae for mean coordination numbers in clusters

Abstract: Rigorous analytical formulae for mean nearest-neighbour coordination numbers in clusters as a function of cluster size have been derived for a range of geometries: the tetrahedron, octahedron, cuboctahedron, icosahedron and bcc rhombic dodecahedron. Formulae for outer-neighbour coordination numbers are also reported, including a complete analysis of interatomic distances and mean coordination numbers in icosahedra. The formulae will find application in studies of electronic structure and interpretation of EXAFS data.

Mapping of octopamine-immunoreactive neurons in the central nervous system of the lobster.

Abstract: It has been suggested that serotonin and octopamine serve important roles in behavioral regulation in lobsters. In this paper the locations of octopamine-immunoreactive neurons were mapped in wholemount preparations of the ventral nerve cord of 4th stage lobster (Homarus americanus) larvae. Approximately 86 neurons were found, distributed as follows: brain, 12; circumesophageal ganglia, 2; subesophageal ganglion, 38; thoracic ganglia, 6 each; and 4th and 5th abdominal ganglia, 2 each. All the octopamine-immunoreactive neurons are paired and located along the midline. Of the 86 neurons, 28 were identified as neurosecretory, and 26 as intersegmental ascending thoracic, ascending abdominal, or descending interneurons. The neurosecretory system is arranged segmentally and located entirely within the thoracic and subesophageal neuromeres with extensive terminal fields of endings along 2nd thoracic and subesophageal nerve roots. This set of neurons shares the features of central and peripheral endings with 2 pairs of large serotonin-containing neurosecretory neurons found in the fifth thoracic and first abdominal ganglia. The intersegmental neurons include: (1) two cells in the brain and 2 pairs of cells in the 3rd and 4th neuromeres of the subesophageal ganglion, which project to the 6th abdominal ganglion; (2) a segmentally organized group of ascending internurons found in the subesophageal and in all thoracic ganglia; and (3) pairs of ascending interneurons found in the 4th and 5th ganglia in the abdominal nerve cord. By means of a biochemical assay, the cell bodies of octopamine-immunoreactive neurosecretory cells in the thoracic segment of the nerve cord were found to contain 40–100 fmol of octopamine, while control neurons had none. © 1993 Wiley-Liss, Inc.

Differential diagnosis of adenomas and dysplastic lesions in patients with ulcerative colitis.

Abstract: In a retrospective study, unequivocal neoplastic lesions (126 circumscribed lesions, 10 large-area lesions) in 76 patients with known ulcerative colitis were classified into adenomas and dysplastic lesions on the basis of pathomorphological criteria The macroscopic appearance, gland architecture, mucin vacuoles, the appearance of the nucleus, the stroma/gland ratio, the position of the proliferation zone, the interface between the lesion and the surrounding mucosa, and the state of neighbouring mucosa were all assessed In 31 patients (41%), the lesions were classified as adenomas, in 42 patients (55%) as dysplastic lesions A further three patients (4%) were found to have both adenomas and dysplastic lesions The average age of the patients with adenomas was 660 years, that of those with dysplastic lesions 434 years The mean duration of the disease in patients with adenomas was 72 years, and in patients with dysplastic lesions 126 years Among the patients with adenomas, 65% has solitary and 35% multiple lesions; among the patients with dysplastic lesions, the corresponding figures were 27% and 73% No significant differences were found in sex distribution, the extent of the ulcerative colitis or the site of the lesions Successful differentiation between adenomas and dysplastic lesions in ulcerative colitis patients requires a differentiated therapeutic response

Genetic organization of the streptokinase region of the Streptococcus equisimilis H46A chromosome

Abstract: The complete nucleotide sequences of four genes and one open reading frame (ORF1) adjacent to the streptokinase gene, skc, from Streptococcus equisimilis H46A were determined. These genes are encoded on the opposite DNA strand to skc and are arranged as follows: dexB-abc-lrp-skc-ORF1-rel. The dexB gene, coding for an α-glucosidase (Mr 61733), and abc, encoding an ABC transporter (Mr 42080), are similar to the dexB and msmK genes, respectively, from the multiple sugar metabolism operon of S. mutans. The lrp gene specifies a leucine-rich protein (Mr 32302) that has a leucine-zipper motif at its C-terminus. The function of the Lrp protein is not known but appeared to be detrimental when overexpressed in Escherichia coli. Although lrp appears not to be an essential gene, as judged by plasmid insertion mutagenesis, it is conserved in all streptococcal strains carrying a streptokinase gene. The rel gene showed significant homology to the E. coli relA and spoT genes involved in the stringent response to amino acid deprivation. Multiple alignment of the amino acid sequences of Rel (Mr 83913), RelA and SpoT revealed 59.4% homology of the primary structures. Northern hybridiziatioo analyses of the genes in the skc region showed skc to be transcribed most abundantly. In addition to transcripts for skc, monocistronic mRNAs were detected for all three genes divergently transcribed from skc. Although there was also some read-through transcription from lrp into abc, and from abc into dexB, the transcription pattern suggests a high degree of transcriptional and functional independence not only of skc but also abc and dexB. Prominent structural features in intergenic regions included a static DNA bending locus located upstream and a putative bidirectional transcription terminator downstream of skc.

Investigation of poly(arylenevinylene)s, 40. Electrochemical studies on poly(p‐phenylenevinylene)s

Abstract: Differential pulse polarography (DPP) and cyclovoltammetry (CV) were conducted to study the redox behaviour of poly(p-phenylenevinylene) (PPV; E = 0,76 V; E = −1,74 V) as well as of three insoluble PPV-derivatives and four soluble aryl-substituted PPV's. Oxidation studies of DP-PPV, DMOP-PPV and DPOP-PPV in comparison with two series of the oligomeric model compounds 1a–e and 2a–d lead to the conclusion that for DMOP-PPV (E = 0,98, 1,24,1,31 V) and DPOP-PPV (E = 1,10, 1,29, 1,44 V) three distinct oxidation stages exist, which are reversibly occupied and represent 1/2, 1 and 2 positive charges per repeating unit. In DP-PPV two oxidation stages representing 1/2 and 1 positive charges were found to be reversibly occupied (E = 1,17, 1,69 V), whereas at higher potentials irreversible dehydrocyclization occurred.

Metabolism of phenol, chloro- and nitrophenols by the Penicillium strain Bi 7/2 isolated from a contaminated soil.

Abstract: The Penicillium strain Bi 7/2 able to grow on phenol as sole source of carbon and energy was isolated from a contaminated soil in Bitterfeld (East Germany). The strain is adapted to high phenol concentrations. Spores germinated still at a phenol concentration of 1.5 g/l. Phenol is degraded by the ortho-pathway with catechol as first intermediary product. The Penicillium strain metabolizes 4-, 3- and 2-chlorophenol with decreasing rates with phenol or glucose as cosubstrate. In the case of 4-chlorophenol 4-chlorocatechol was detected as intermediary product, further degraded as indicated by release of about 35% of the bound chlorine of the aromatic molecule. The strain also cometabolically metabolizes 4-, 3- and 2-nitrophenol. The final product of 3- and 4-nitrophenol is 4-nitrocatechol.

Polymorphism of the Streptokinase Gene: Implications for the Pathogenesis of Post-Streptococcal Glomerulonephritis

Abstract: Summary Recent studies of streptokinase genes from epidemiologically and clinically defined streptococci of groups A, C and G have provided evidence of the polymorphism of the streptokinase locus in the chromosome of pathogenic streptococci. This review considers genetic and pathogenetic data suggesting that there exists a causal relationship between nephritis strain-associated streptokinase production and the initial stages of post-streptococcal glomerulonephritis (PSGN). Currently available sequence information allows to recognize, in the middle of the streptokinase molecule, a major variable region, VI, of about 70 amino acid residues in which sequence identity drops to below 50% when the proteins from nephritogenic and non-nephritogenic strains are compared. The VI regions, although showing microheterogeneity within either protein category, appear to be more hydrophobic and possess a higher content of ordered secondary structures in the “nephritogenic” molecules. As a working hypothesis, they may be considered the nephrotrojiic domain(s) with which streptokinases from nephritogenic strains bind to glomerular structures and activate plasminogen in situ, thus triggering the cascade of proteolytic processess leading to PSGN.

Functional aspects of secondary carotenoids in Haematococcus lacustris (Girod) Rostafinski (Volvocales): I. The accumulation period as an active metabolic process.

Abstract: SUMMARY Alterations of photosynthetic activity were investigated during accumulation of secondary carotenoids in Haematococcus lacustris (Girod) Rostafinski. Using several methods regarding (i) pigment pattern and pigment content (cytophotometry, computer-aided microscopic image analysis, in vivo absorption spectroscopy, high-performance liquid chromatrography) and (ii) photosynthesis (microfluorometry, modulated chlorophyll fluorescence and luminescence detection, O2 evolution and consumption measurement, 77 K fluorescence spectroscopy) we examined single cells and cell suspensions of the green alga. The results indicate decrease of both the photosystem II activity and the linear electron transport accompanying synthesis of secondary carotenoids. On the other hand, activation of those processes leading to an increased transthylakoid proton gradient could be established during early accumulation period. This is assumed to be an active adaptation of the photosynthetic apparatus to energetic requirements given by secondary carotenoid biosynthesis in H. lacustris.

On additive Schwarz preconditioners for sparse grid discretizations

Abstract: Based on the framework of subspace splitting and the additive Schwarz scheme, we give bounds for the condition number of multilevel preconditioners for sparse grid discretizations of elliptic model problems For a BXP-like preconditioner we derive an estimate of the optimal orderO(1) and for a HB-like variant we obtain an estimate of the orderO(k 2 ·2 k/2 ), wherek denotes the number of levels employed Furthermore, we confirm these results by numerically computed condition numbers

Enzymes of glutathione synthesis in dog skeletal muscles and their response to training

Abstract: The glutathione synthesizing enzymes, gamma-glutamyl cysteinyl synthetase and glutathione synthetase, were found in all skeletal muscles studied in dogs. Both occurred also in the liver, but only the former in the lung. The influence of physical training on these enzyme activities was also investigated. For 30 weeks the dogs ran 5 days week-1 on a treadmill at a 15 degrees uphill grade. A 1.5- to 2-fold increase in the gamma-glutamyl cysteinyl synthetase and 3-fold increase in the glutathione synthetase activities was observed in muscles affected by the training procedure (m. triceps, m. extensor carpi radialis and m. gastrocnemius). No training effect could be observed in the splenius and longissimus dorsi muscles or in the liver. The training increased total glutathione levels in the lung and gastrocnemius muscle as well as in the plasma. Glutathione disulfide levels were not altered. Acute physical exercise significantly decreased the plasma total glutathione concentrations in the trained dogs. The results indicate a training responsive adaptation of glutathione system in skeletal muscle.