Showing papers by "University of Jena published in 1994"
TL;DR: Structures formed during interaction of cationic liposomes and plasmid DNA were studied by freeze—fracture electron microscopy and their morphology was found to be dependent on incubation time and DNA concentration.
436 citations
Journal Article•
TL;DR: These potent and selective compounds represent leads for the development of novel agents to combat tumors driven by PDGF or to inhibit PDGF action in other diseases in which PDGF plays a key role, such as restenosis.
Abstract: A novel class of tyrosine kinase blockers represented by the tyrphostins AG1295 and AG1296 is described. These compounds inhibit selectively the platelet-derived growth factor (PDGF) receptor kinase and the PDGF-dependent DNA synthesis in Swiss 3T3 cells and in porcine aorta endothelial cells with 50% inhibitory concentrations below 5 and 1 microM, respectively. The PDGF receptor blockers have not effect on epidermal growth factor receptor autophosphorylation; weak effects on DNA synthesis stimulated by insulin, by epidermal growth factor, or by a combination of both; and over an order of magnitude weaker blocking effect on fibroblast growth factor-dependent DNA synthesis. AG1296 potently inhibits signaling of human PDGF alpha- and beta-receptors as well as of the related stem cell factor receptor (c-Kit) but has no effect on autophosphorylation of the vascular endothelial growth factor receptor KDR or on DNA synthesis induced by vascular endothelial growth factor in porcine aortic endothelial cells. Treatment by AG1296 reverses the transformed phenotype of sis-transfected NIH 3T3 cells but has no effect on src-transformed NIH 3T3 cells or on the activity of the kinase p60c-src(F527) immunoprecipitated from these cells. These potent and selective compounds represent leads for the development of novel agents to combat tumors driven by PDGF or to inhibit PDGF action in other diseases in which PDGF plays a key role, such as restenosis.
294 citations
TL;DR: For a description of junction properties, the Blonder-Tinkham-Klapwijk theory was used where the finite lifetime of the quasiparticles was included.
Abstract: ${\mathrm{Bi}}_{2}$${\mathrm{Sr}}_{2}$${\mathrm{CaCu}}_{2}$${\mathrm{O}}_{\mathit{y}}$/Au point-contact junctions have been studied. For a description of junction properties we used the Blonder-Tinkham-Klapwijk theory where we included the finite lifetime of the quasiparticles. From the fitting procedures of the experimental differential characteristics, the values of the Fermi velocity ${\mathit{v}}_{\mathit{F}}$\ensuremath{\simeq}5\ifmmode\times\else\texttimes\fi{}${10}^{7}$ cm/s, the ratio 2\ensuremath{\Delta}/${\mathit{k}}_{\mathit{B}}$${\mathit{T}}_{\mathit{c}}$\ensuremath{\simeq}8, and the coherence length ${\ensuremath{\xi}}_{\mathit{a}\mathit{b}}$\ensuremath{\simeq}35 \AA{} for ${\mathrm{Bi}}_{2}$${\mathrm{Sr}}_{2}$${\mathrm{CaCu}}_{2}$${\mathrm{O}}_{\mathit{y}}$ were obtained.
193 citations
TL;DR: The organization of putative octopaminergic pathways in the brain and subesophageal ganglion of the honeybee was investigated with a well‐defined polyclonal antiserum against octopamine.
Abstract: The organization of putative octopaminergic pathways in the brain and subesophageal ganglion of the honeybee was investigated with a well-defined polyclonal antiserum against octopamine. Five prominent groups of just over 100 immunoreactive (IR) somata were found in the cerebral ganglion: Neurosecretory cells in the pars intercerebralis innervating the corpora cardiaca via NCC I, one cluster mediodorsal to the antennal lobe, one scattered on both sides of the midline of the protocerebrum, one between the lateral protocerebral lobes and the dorsal lobes, and a single soma on either side of the central body. With the exception of the pedunculi and β-lobes of the mushroom bodies, varicose immunoreactive fibers penetrate all parts of the cerebral ganglion. Strong labelling was found in the central complex and the protocerebral bridge. Fine networks of labelled processes invade the antennal lobes, the calyces and a small part of the α-lobes of the mushroom bodies, the protocerebrum, and all three optic ganglia.
In the subesophageal ganglion, one labelled cell body was found in the lateral soma layer of the mandibular segment. Each of the three neuromeres contains a group of six to ten somata in the ventral median parts. Most of the ventral median cells send their neurites dorsally through the midline tracts, whereas the neurites of a few cells follow the ventral cell body neurite tracts.
Octopamine-IR was demonstrated in all neuropils that contain pathways for proboscis extension learning in honeybees. Because octopaminergic mechanisms seem to be involved in the behavioral plasticity of the proboscis extension reflex, our study provides anatomical data on the neurochemical organization of an appetitive learning paradigm. © 1994 Wiley-Liss, Inc.
186 citations
TL;DR: In this paper, the structure, protein-binding properties and relationship between M1 protein and Protein H were investigated and shown to have high degree of similarity in the signal peptides, the C repeats located in the central parts of the molecules and in the C-terminal cell-wall-attached regions, whereas the Nterminal sequences showed no significant similarity.
Abstract: M1 protein and Protein H are surface proteins simultaneously present at the surface of certain strains of Streptococcus pyogenes, important pathogenic bacteria in humans. The present study concerns the structure, protein-binding properties and relationship between these two molecules. The gene encoding M1 protein (emm1) was found immediately upstream of the Protein H gene (sph). Both genes were preceded by a promoter region. Comparison of the sequences revealed a high degree of similarity in the signal peptides, the C repeats located in the central parts of the molecules and in the C-terminal cell-wall-attached regions, whereas the N-terminal sequences showed no significant similarity. Protein H has affinity for the Fc region of IgG antibodies. Also M1 protein, isolated from streptococcal culture supernatants or from Escherichia coli expressing emm1, was found to bind human IgGFc. When tested against polyclonal IgG from eight other mammalian species, M1 protein and Protein H both showed affinity for baboon, rabbit and pig IgG. M1 protein also reacted with guinea-pig IgG, whereas both streptococcal proteins were negative in binding experiments with rat, mouse, bovine and horse IgG. The two proteins were also tested against other members of the immunoglobulin super family: human IgM, IgA, IgD, IgE, beta 2-microglobulin, and major histocompatibility complex (MHC) class-I and class-II antigens. M1 protein showed no affinity for any of these molecules whereas Protein H reacted with MHC class-II antigens. M1 protein is known to bind albumin and fibrinogen also. The binding sites for these two plasma proteins and for IgGFc were mapped to different sites on M1 protein. Thus albumin bound to the C repeats and IgGFc to a region (S) immediately N-terminal of the C repeats. Finally, fibrinogen bound further towards the N-terminus but close to the IgGFc-binding site. On the fibrinogen molecule, fragment D was found to mediate binding to M1 protein. The IgGFc-binding region of M1 protein showed no similarity to that of Protein H. Still, competitive binding experiments demonstrated that the two streptococcal proteins bound to overlapping sites on IgGFc.
178 citations
TL;DR: Strain SAS56, an ascospore line used routinely for genetic analyses, is probably polyploid, since treatment with benomyl causes a significant reduction in DNA content per nucleus, and the putative haploid derivatives of SAS56 resemble the parent strain in their parasitic and physiological properties.
Abstract: Field isolates and laboratory strains of Botrytis cinerea, an ascomycetous fungus causing considerable economic losses, e.g., as “grey mould” of vine, were compared for differences in ploidy level by determining their DNA content per nucleus. Strain SAS56, an ascospore line used routinely for genetic analyses, is probably polyploid, since treatment with benomyl causes a significant reduction in DNA content per nucleus. This conclusion is substantiated by the increased sensitivity of the putative haploid derivatives to mutagens (UV and EMS). Molecular analyses (RAPD) of the haploidized strains indicate a very limited degree of heterozygosis of the parent strain SAS56. Analysis of field isolates of B. cinerea showed that their DNA content per nucleus varied considerably, indicating that aneuploidy/polyploidy is a widespread phenomenon in this species. This can explain both the variability and phenotypic instability of many field isolates of this fungus and the unusual difficulties faced by researchers in recovering stable recessive laboratory mutants. Since the haploid derivatives of SAS56 resemble the parent strain in their parasitic and physiological properties they should provide a good basis for classical and molecular genetic studies.
172 citations
TL;DR: Evidence is provided that glial cells from an intact tissue express receptors for the most abundant transmitters in the central nervous system, glutamate, and GABA.
Abstract: In this study, the patch-clamp technique was applied to brain slices to test for the presence of GABAA and glutamate receptors in glial cells of an intact tissue preparation, the hippocampus from 9-12 day old mice. Two types of glial cells were studied in the CA1 stratum pyramidale, termed passive and complex cells, which were distinct by their characteristic pattern of voltage-dependent currents. Both cell types were previously identified as glial by combining electrophysiology with ultrastructural inspection (Steinhuser et al., 1992, Eur J Neurosci 4:472-484). A subpopulation of passive cells was positive, all complex cells were negative for immunocytochemical staining against glial fibrillary acidic protein, a marker of mature astrocytes. In both cell types, GABA activated currents compatible with GABAA-receptor mediated responses. The glutamate response in complex and in most of the passive cells was mediated by a ligand-gated ion channel and closely matched the pharmacology of the kainate receptor. Activation of glutamate receptors led to a transient decrease of the resting K+ conductance in complex cells and to an irreversible decrease in the passive cells. In three passive cells, glutamate-activated currents were most likely dominated by an electrogenic uptake. In a small group of passive cells NMDA-activated currents were observed. This study provides evidence that glial cells from an intact tissue express receptors for the most abundant transmitters in the central nervous system, glutamate, and GABA.
169 citations
TL;DR: In this article, a new acetylene complex of titanocene and permethyltitanocene Cp 2 Ti(R 1 C 2 R 2 ) and Cp *Ti(Me 3 SiC 2 SiMe 3 ) with equimolar amounts of Mg and the appropriate acetylene R 1 C2 R 2 in THF was obtained.
159 citations
TL;DR: In this article, it is shown that neutral rhodium(I) hydride complexes are the actual active species in the catalytic cycle and a mechanism is proposed on the basis of these results that allows explanation of all experimental data including the induction period and activation of the catalyst by treatment with H2 or HCO2H prior to the reaction observed with the precursor.
145 citations
TL;DR: In this paper, the substituent pattern of carboxymethyl cellulose (CMC) was determined by means of high-performance liquid chromatography, where the hydrolysates of CMC were separated on a polystyrene-based strong cation-exchange resin into glucose, 2,3,6-tri-O-carboxyldimethyl glucose and groups of 2, 3,and 6-mono-O -carboxylated and unsubstituted units.
Abstract: A rapid and convenient procedure was developed for the determination of the substituent pattern of carboxymethyl cellulose (CMC) by means of high-performance liquid chromatography. The hydrolysates of CMC are separated on a polystyrene-based strong cation-exchange resin into glucose, 2,3,6-tri-O-carboxymethyl glucose and groups of 2-, 3-and 6-mono-O- and 2,3-, 2,6-, and 3,6-di-O-carboxymethyl glucoses. By this method the determination of the average degree of substitution as well as the substituent pattern is possible. In this way we found that CMC samples which were synthesized in LiCl/N,N-dimethylacetamide as a cellulose solvent, contain a significantly higher amount of both tricarboxymethylated and unsubstituted units than those obtained in a slurry of cellulose in isopropanol/water at comparable DS values. The substituent pattern of heterogeneously synthesized CMC is mainly determined by statistics.
114 citations
TL;DR: The cineradiographic study of the locomotion of the rock hyrax and the functional interpretation of its locomotory system reveals that the main action of proximal segments is combined with flexed position and low movements of limb joints.
TL;DR: It is concluded that glutamate receptor activation leads to complex and variable changes in different types of glial cells; the functional importance of these changes is as yet unresolved.
Abstract: Glial cells in the CA1 stratum radiatum of the hippocampus of 9- to 12-day-old mice show intrinsic responses to glutamate due to the activation of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)/kainate receptors. In the present study we have focused on a subpopulation of the hippocampal glial cells, the "complex" cells, characterized by voltage-gated Na+ and K+ channels. Activation of glutamate receptors in these cells led to two types of responses, the activation of a cationic conductance, and a longer-lasting blockade of voltage-gated K+ channels. In particular, the transient (inactivating) component of the outwardly rectifying K+ current was diminished by kainate. Concomitantly, as described in Bergmann glial cells, kainate also elevated cytosolic Ca2+. This increase was due to an influx via the glutamate receptor itself. In contrast to Bergmann glial cells, the cytosolic Ca2+ increase was not a link to the K+ channel blockade, since the blockade occurred in the absence of the Ca2+ signal and, vice versa, an increase in cytosolic Ca2+ induced by ionomycin did not block the transient K+ current. We conclude that glutamate receptor activation leads to complex and variable changes in different types of glial cells; the functional importance of these changes is as yet unresolved.
TL;DR: Different methods for formation of hollow fibres during biosynthesis were investigated and the polymer formed is free of other biogenic compounds, separable in a simple way and characterized by its high water- absorption capacity.
TL;DR: The applicational aspects of this strong red shift are outlined with respect to scinitillators, solar collectors, and biological fluorescence probese, and the unusual fluorecence properties of a pyrazalocoumarin derivative are described.
Abstract: Various adiabatic photochemical mechanisms are compared which lead to a product in the excited state and therefore often to strongly red-shifted fluorescence. The applicational aspects of this strong red shift are outlined with respect to scinitillators, solar collectors, and biological fluorescence probese. As an example, the unusual fluorecence properties of a pyrazalocoumarin derivative are described.
TL;DR: Steps preceding stable RNA duplex formation are sufficient to induce RNAIII‐dependent termination of nascent RNAII transcripts, and inhibition rate constants were calculated.
Abstract: Antisense RNA-mediated transcriptional attenuation is the mode of replication control of several plasmids, among them pIP501. This mechanism implies that the repR mRNAs can fold into two mutually exclusive structures. The formation of one of these structures is induced by binding of the antisense RNA and results in premature termination. Since the fate of the nascent mRNA transcripts depends on the binding rate of the antisense RNA to its target, the control is kinetic. We have studied the antisense RNA, RNAIII, and target RNA, RNAII, whose interaction determines the replication frequency of plasmid pIP501. RNA secondary structures were analyzed using structure-specific RNases. RNA binding was studied in vitro with normal size and truncated RNAIII species. An in vitro single-round attenuation assay was developed that permits qualitative and quantitative assessment of inhibition by RNAIII. The effect of varying concentrations of RNAIII species on attenuation was tested and inhibition rate constants were calculated. The inhibition rate constants were at least 10 times higher than the pairing rate constants. Thus, steps preceding stable RNA duplex formation are sufficient to induce RNAIII-dependent termination of nascent RNAII transcripts.
TL;DR: Extrachloroplastic accumulation of secondary carotenoids in H. lacustris can be interpreted as a specific adaptation to habitats that exhibit strong insolation.
Abstract: We investigated the protection from photoinhibition by different developmental stages of Haematococcus lacustris [Girod] Rostafinski using chlorophyll fluorescence measurements of single cells and suspensions. An overall correlation between higher cellular content of secondary carotenoids and the capacity to withstand excessive irradiation was observed in flagellated cells and aplanospores of H. lacustris. Low-light-reversible spreading of extra-chloroplastic secondary carotenoids occurred in the periphery of the cell during strong irradiation. This process resulted in increased shading of the cup-shaped chloroplast as demonstrated by a decrease in chlorophyll fluorescence. Extrachloroplastic accumulation of secondary carotenoids in H. lacustris can be interpreted as a specific adaptation to habitats that exhibit strong insolation.
TL;DR: These results support models in which promoter activity can be determined by various rate limiting steps, including those following the formation of open complexes and even the initiation of RNA synthesis.
TL;DR: Examination of the composition of extracellular matrix in relation to the myofibroblast phenotype in proliferative nodules from 13 native surgical specimens of nodular palmar fibromatosis substantiate an extrace cellular matrix formation by my ofibroblasts with fibronectin, laminin, collagen type IV and tenascin as constituents.
Abstract: The proliferative nodules of Dupuytren’s disease are electron microscopically characterized by the occurrence of myofibroblasts with a basal lamina-like material. As reported in the literature, immuno
TL;DR: The results identify lgGFc‐ and albumin binding regions of protein H and further define and emphasize the convergent evolution among bacterial surface proteins interacting with human plasma proteins.
Abstract: Protein H, a molecule expressed at the surface of some strains of Streptococcus pyogenes, has affinity for the constant (IgGFc) region of immunoglobulin (Ig) G. In absorption experiments with human plasma, protein H-sepharose could absorb not only IgG but also albumin from plasma. The affinity constant for the reaction between albumin and protein H was 7.8 x 10(9) M-1, which is higher than the affinity between IgG and protein H (Ka = 1.6 x 10(9) M-1). Fragments of protein H were generated with deletion plasmids and polymerase chain reaction (PCR) technology. Using these fragments in various protein-protein interaction assays, the binding of albumin was mapped to three repeats (C1-C3) in the C-terminal half of protein H. On the albumin molecule, the binding site for protein H was found to overlap the site for protein G, another albumin- and IgGFc-binding bacterial surface protein. Also IgGFc-binding could be mapped with the protein H fragments and the region was found N-terminally of the C repeats. A synthetic peptide (25 amino acid residues long) based on a sequence in this region was shown to inhibit the binding of protein H to immobilized IgG or IgGFc. This sequence was not found in previously described IgGFc-binding proteins. However, two other cell surface proteins of S. pyogenes exhibited highly homologous regions. The results identify IgGFc- and albumin-binding regions of protein H and further define and emphasize the convergent evolution among bacterial surface proteins interacting with human plasma proteins.
TL;DR: In this article, a theoretical interpretation of the empirically determined correlations by the calculation of the bond-polarization energy V HO characterizing the influence of neighboring atoms on the charge distribution in an O-H bond is presented.
TL;DR: Cadmium exposure of soils and flora is not reflected in the food chain of the inhabitants of Bad Liebenstein and health risks caused from cadmium can be excluded.
TL;DR: In this paper, the patch-clamp technique in the whole-cell mode was applied to identified cells in situ and to glial cells acutely isolated from tissue slices, where the outward current was composed of two components: a sustained and a transient current.
Abstract: In the present study, we were interested in a quantitative analysis of voltage-activated channels in a subpopulation of hippocampal glial cells, termed “complex” cells. The patch-clamp technique in the whole-cell mode was applied to identified cells in situ and to glial cells acutely isolated from tissue slices. The outward current was composed of two components: a sustained and a transient current. The transient K+ channel had electrophysiological and pharmacological properties resembling those of the channel through which the A-currents pass. In addition, this glial A-type current possessed a significant Ca2+ dependence. The current parameters determined in situ or in isolated cells corresponded well. Due to space clamp problems in situ, properties of voltage-dependent Na+ currents were only analysed in suspended glial cells. The tetrodotoxin (TTX) sensitivity and the stationary and kinetic characteristics of this current were similar to corresponding properties of hippocampal neurons. These quantitative data demonstrate that at an early postnatal stage of central nervous system maturation, glial cells in situ express a complex pattern of voltage-gated ion channels. The results are compared to findings in other preparations and the possible consequences of transmitter-mediated channel modulation in glial cells are discussed.
TL;DR: Phosphate-solubilizing bacteria isolated from the rhizosphere of wheat and rye plants produced plant growth regulating substances of the auxin type when cultivated in liquid culture supplemented with tryptophane, with significant differences in the amount of auxins produced by different strains.
TL;DR: In this article, the spectroscopic, luminescence-kinetic and laser properties of co-doped fluoride phosphate and phosphate glasses are given, and they show that a marginal increase of laser efficiency is achieved as a result of nonradiative deactivation of Cr3+, connected with increasing temperature of the active laser media.
Abstract: Spectroscopic, luminescence-kinetic and laser properties of CeCrNd co-doped fluoride phosphate and phosphate glasses are given. Ce3+ ions act efficiently as sensitizer and Ce 3+ 4+ ions, incorporated in glasses, prevent UV radiation damage. The co-doping of Cr3+ ions produces only a marginal increase of laser efficiency as the result of non-radiative deactivation of Cr3+, connected with increasing temperature of the active laser media. Fluoride phosphate glasses with phosphate contents between 10 and 20 mol% are good hosts for Nd3+ laser ions.
TL;DR: In this paper, the influence of the redox states of Fe, Cu, Pb and Ni in the ppm range on the ultraviolet absorption was investigated, and the individual absorption coefficients per ppm ion and redox equilibria resulting from the melting conditions and refining temperature were determined.
Abstract: Fluoride phosphate glasses are attractive candidates for high-performance glass for the deep ultraviolet range. The calculated values for the ultraviolet resonance wavelengths are comparable with those of CaF2, BeF2 and SiO2. However, the experimental ultraviolet transmission of glass is frequently limited by extrinsic absorption due to trace impurities, mainly transition metals. The influence of the redox states of Fe, Cu, Pb and Ni in the ppm range on the ultraviolet absorption was investigated. The individual absorption coefficients per ppm ion and the redox equilibria resulting from the melting conditions and refining temperature were determined. Fe3+, Cu2+ and Pb2+ have the largest influence on the ultraviolet absorption. Glasses melted under reducing conditions have much higher ultraviolet transmission at 250 nm than glassees melted under oxidizing conditions. The ultraviolet absorption of the glass is strongly dependent on the reducing temperature. The ultraviolet absorption decreases and the luminescence increases drastically with increasing reducing temperature from 850 to 1100°C. The redox equilibria are shifted to Fe2+ and Cu+, over 1100°C towards Cu0 colloids too. The molar absorption coefficients in the ultraviolet range of the lower redox states are more than one order lower than those of the higher redox states.
TL;DR: In comparison to the results obtained with sera from blood donors, it became evident that both types of infection result in significant changes in the profile of LPS antibodies.
Abstract: An artificial glycoconjugate containing, as a ligand, the deacylated carbohydrate backbone of a recombinant Chlamydia -specific lipopolysaccharide was used as a solid-phase antigen in ELISA to measure antibodies against chlamydial LPS. The specificity and reproducibility of the assay was shown by using a panel of prototype monoclonal antibodies representing the spectrum of antibodies also occuring in patient sera. These mAbs recognized Chlamydia -specific epitopes [ α 2→8-linked disaccharide of 3-deoxy- d - manno -octulosonic acid (Kdo) or the trisaccharide α Kdo-(2→8)-→Kdo] or those shared between chlamydial and Re-type LPS ( α Kdo, α →4-linked Kdo disacccharide). The assay was used to measure IgG, IgA and IgM antibodies against chlamydial LPS in patients with genital or respiratory tract infections. In comparison to the results obtained with sera from blood donors, it became evident that both types of infection result in significant changes in the profile of LPS antibodies.
TL;DR: In this article, the exact asymptotics of μ(Bργαρατεραβραγαβαγεβαβγαγγε βαγδαβεβγεγαταβδεβεγγγα βαββγγβε βγγ βγααγβγβα βγγγγθ βγβθ αγγϵβγεβατ βγ βρα
Abstract: Let μ be a centered Gaussian measure on a Hilbert spaceH and let
$$B_R \subseteq H$$
be the centered ball of radiusR>0. Fora∈H and
$$\mathop {\lim }\limits_{t{\mathbf{ }} \to {\mathbf{ }}\infty } {\mathbf{ }}R(t)/t< {\mathbf{ }}||a||$$
, we give the exact asymptotics of μ(B
R(t)+t·a) ast→∞. Also, upper and lower bounds are given when μ is defined on an arbitrary separable Banach space. Our results range from small deviation estimates to large deviation estimates.
TL;DR: Results suggest that the same molecular interaction gives rise to both inhibition and activation in promoters, likely to be due to facilitated RNA polymerase binding in the presence of A-tracts, which stimulates binding-limited promoters but inhibits promoter function in which polymerase escape and promoter clearance is rate limiting.
TL;DR: In this article, the structure of an unknown complex phosphate phase was investigated and the change of Q[2] group content during heat treatment was discussed. And the structures of these materials were analyzed as a function of MgO and Al2O3 content.
Abstract: 31P and 27Al magic angle spinning (MAS)-nuclear magnetic resonance (NMR) measurements were used to investigate P2O5CaONa2O(Al2O3) and P2O5CaONa2OMgO(Al2O3) glasses and glass ceramics. The structures of these materials were analyzed as a function of MgO and Al2O3 content. The change of Q[2] group content during heat treatment is discussed. The structure of an unknown complex phosphate phase was investigated.