TY  - JOUR
A1  - Hacker, Jörg
A1  - Knapp, S.
A1  - Goebel, W.
T1  - Spontaneous deletions and flanking regions of the chromosomal inherited hemolysin determinant of an Escherichia coli 06 strain
N2  - The hemolytic Escherichia coli strain 536 (06) propagates spontaneous hemolysin- negative mutants at relatively high rates (10-3 to 10-4 ). One type of mutant (type I) lacks both secreted (external) and periplasmic (internal) hemolysin activity (HlYex - IHlYin -) and in addition shows no mannose-resistant hemagglutination (Mrh -), whereas the other type (type II) is HlYex -IHIYin + and Mrh +. The genetic determinants for hemolysin production (hly) and for mannose-resistant hemagglutination (mrh) of this strain are located on the chromosome. Hybridization experiments with DNA probes specific for various parts of the hly determinant reveal that mutants of type I have lost the total hly determinant, whereas those of type 11 lack only part of the hlyB that is essential for transport of hemolysin across the outer membrane. Using a probe that contains the end sequence of the plasmid pHly152-encoded hly determinant (adjacent to hlyB), we determined that a related sequence flanks also the hlyB-distal end of the chromosomal hly determinant of E. coli 536. In addition several other similar or even identical sequences are found in the vicinity of the hlyC- and the hlyB-distal ends of both the chromosomal and the plasmid hly determinants.
Y1  - 1983
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-40260
ER  - 
TY  - JOUR
A1  - Berger, Harald
A1  - Hacker, Jörg
A1  - Juarez, Antonio
A1  - Hughes, Colin
A1  - Goebel, Werner
T1  - Cloning of the chromosomal determinants encoding hemolysin production and mannose-resistant hemagglutination in Escherichia coli
N2  - We have cloned the chromosomal hemolysin determinants from Escherichia coli strains belonging to the four O-serotypes 04, 06, 018, and 075, The hemolysin-producing clones were isolated from gene banks of these strains which were constructed by inserting partial Sau3A fragments of chromosomal DNA into the cosmid pJC74. The hemolytic cosmid clones were relatively stable. The inserts were further sub cloned either as Sail fragments in pACYC184 or as BamHI-SaLI fragments in a recombinant plasmid (pANN202) containing cistron C (hlye) of the plasmid-encoded hemolysin determinant. Detailed restriction maps of each of these determinants were constructed, and it was found that, despite sharing overall homology, the determinants exhibited minor specific differences in their structure, These appeared to be restricted to cistron A (hlyA), which is the structural gene for hemolysin. In the gene banks of two of these hemolytic strains, we could also identify clones which carried the genetic determinants for the mannose-resistant hemagglutination antigens Vb and VIc. Both of these fimbrial antigens were expressed in the E. coli K-12 clones to an extent similar to that observed in the wild-type strains. These recombinant cosmids were rather unstable, and, in the absence of selection, segregated at a high frequency.
Y1  - 1982
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-40255
ER  - 
TY  - JOUR
A1  - Hof, H.
A1  - Emmerling, P.
A1  - Hacker, Jörg
A1  - Hughes, C.
T1  - The role of macrophages in primary and secondary infection of mice with Salmonella typhimurium
N2  - Elimination of macrophages with high-molecular dextran sulphate (OS) markedly impairs resistance of mice to primary infection with smooth, virulent strains of Salmonella typhimurium, whereas stimulation of this system by killed Bordetella pertussis organisms increases resistance. In infection with rough, avirulent strains of S. iyphimurium the elimination of macro phages was not followed by an essential loss of resistance, and it appears that other non-specific defence mechanisms, for example the complement system, may have compensated for the lack of macrophages. Macrophages, therefore, play an important role in defence during primary infection with virulent strains. In immunity to challenge infection with S. typhimurium, macrophages play an even more significant role. Treatment with OS completely removes immunity, and both humoral and cell-mediated immune mechanisms seem to require the participation of macrophages.
KW  - Macrophage
KW  - Salmonella typhimurium
KW  - Dextran sulphate
KW  - Mouse
KW  - 0 antigen
KW  - Bordeiella pertussis
Y1  - 1982
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-40248
ER  - 
TY  - JOUR
A1  - Burschka, Christian
A1  - Bronger, W.
T1  - Über die Struktur von CsAg\(_3\)S\(_2\) und RbAg\(_3\)S\(_2\)
T1  - The Crystal Structure of cesium silver sulfide (CsAg\(_3\)S\(_2\)) and rubidium silver sulfide (RbAg\(_3\)S\(_2\))
N2  - Die Synthese von CsAg\(_3\)S\(_2\) und RbAg\(_3\)S\(_2\) gelingt durch Umsetzungen von Alkalimetallcarbonaten mit Silber und Schwefel in der Schmelze. Röntgenbeugungsuntersuchungen an Einkristallen ergaben, daß die Schichtstruktur dieser beiden isotypen Verbindungen mit der von K\(_2\)Ag\(_4\)Sa [1] verwandt ist. In allen drei Thioargentaten fanden wir die gleichen röhrenförmigen SilberSchwefel- Verbände. Durch eine verschiedene Verknüpfung dieser Verbände wird der unterschiedlichen Stöchiometrie der Verbindungen Rechnung getragen.
N2  - Fusion reactions of alkali carbonates with silver and sulfur led to the compounds CsAg\(_3\)S\(_2\) and RbAg\(_3\)S\(_2\) X.my investigations on single crystals revealed that their structure is closely related to that of ~A~Sa (1]. A channel-Iike arrangement in the silver·sulfur network was found in both of the structures. According to the difference in stoichiometry. the compounds show a different type of linkage between these silver·sulfur channels.
KW  - Chemie
Y1  - 1977
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31393
ER  - 
TY  - JOUR
A1  - Burschka, Christian
A1  - Baumann, F.-E.
A1  - Schenk, W. A.
T1  - Schwefel(IV)-Verbindungen als Liganden. II. Die Kristall- und Molekülstruktur von Pentacarbonyl-(schwefeldioxid)chrom
T1  - Sulfur(IV) Compounds as Ligands. II. The Crystal and Molecular Structure of Pentacarbonyl-(sulfur dioxide)chromium
N2  - Die Struktur von Pentacarbonyl(schwefeldioxid)chrom (1) wurde röntgenographisch aus Einkristalldaten bestimmt. Die Verbindung kristallisiert mit acht Formeleinheiten in der rhombischen Elementarzelle (Raumgruppe Pbn2\(_1\)) folgender Dimensionen: a = 657,8(2) pm, b = 1245,2(4) pm, c = 2177,4(5) pm (bei 180 K). Das Schwefeldioxid ist \(\eta^1\)-koplanar koordiniert, der Cr-S-Abstand ist mit 219 pm der kürzeste bisher gefundene Abstand zwischen Chrom(O) und Schwefel. Die Cr-C(ax)-Bindung ist mit 189 pm fast genau so lang wie die Cr-C(eq).Bindungen (190 pm), ein Beleg für das hohe \(\pi\)-Akzeptorvermögen des S0\(_2\).
N2  - The structure of pentacarbonyl(sulfurdioxide)chromium (1) has been determined from single crystal X-ray data. The compound crystallizes with eight formula units in the rhombic unit cell (space group Pbn2\(_1\) ) of the dimensions a = 657.8(2) pm, b = 1245.2(4) pm, c = 2177.4(5) pm (at 180 K). The sulfur dioxide ia \(\eta^1\)-coplanar coordinated, the Cr-S distance is 219 pm, the shortest. bond reported so far between chromium(O) and sulfur. The Cr-C(ax) bond (189 pm) was found only marginally shorter than the Cr-C(eq) bonds (190 pm) providing proof of the high \(\pi\)·acceptor capacity of S0\(_2\)
KW  - Chemie
Y1  - 1983
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31388
ER  - 
TY  - JOUR
A1  - Burschka, Christian
A1  - Schenk, W. A.
T1  - Die Kristallstruktur von Tetramethylammonium-Chloropentacarbonylwolframat
T1  - Substituted Halocarbonyl Metallates of Chromium, Molybdenum, and Tungsten. IV. Crystal Structure of Tetramethylammonium Chloropentacarbonyltungstate
N2  - Die Struktur von Tetramethylammoniumchloropentacarbonylwolframat wurde rontgenographisch aue Einkristalldaten bestimmt. Die Verbindung kristallisiert mit vier Formeleinheiten in del' monoklinen Elementarzelle (Raumgruppe P2Jc) folgender Dimensionen: a = 1111,3(4) pm, b = 1110,3(4) pm, c = 1204,1(3) pm, f3 = 99,63(3)°, V = 1464,8 . 106 pm' (R = 0,028). Das Anion besitzt annahernd C4v·Symmetrie mit d(W -C(ois» = 203 pm, d(WC( trans» = 197 pm, d(W-Cl) = 256,6 pm. Zwischen Kation undAnion treten keine ungewohnliche Kontakte auf.
N2  - The structure of tetramethylam~onium chloropentacarbonyltungstate has been determined from single crystal X-ray data. The compound crystallizes with four formula units in the monoclinic unit cell (space group P21!c) of the dimensions a = 1111.3(4) pm, b = 1110.3(4) pm c = 120-1.1(3) pm, fJ = 99.63(3)°, V = 1464.8x 1()6 pm" (R = 0.028). The anion possesses approximately C!v symmetry with the principal interatomic distances d(W -C(cis» = 203 pm, d(WC( trans)) = 197pm dew -Cl) = 256.6 pm. No unusual contacts between cation and anion have been found.
KW  - Chemie
Y1  - 1981
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31417
ER  - 
TY  - JOUR
A1  - Groß, Elisabeth
A1  - Burschka, Christian
A1  - Malisch, Wolfgang
T1  - Hauptgruppenelement-Übergangsmetall-Mehrfachbindungen, IV. Katalytische Assistenz von [Cp(C0)\(_3\)Mo]\(_2\) bei der Aggregation von Metallo-arsanen über Arsen-Metall-Doppelbindungskomplexe
T1  - Main Group Element Transition Metal Multiple Bonds, IV. Catalytic Assistance by [Cp(CO)\(_3\)Mo]\(_2\) in the Aggregation of Metalloarsines via Arsenic Metal Double Bond Complexes
N2  - The metallo-arsanes CP(CO)\(_3\)M - AsMc\(_2\) (1 a, b) (M = Mo, W) are convcrted to the double arsenido-bridged dinuclear complexes [(η-AsMe\(_2\))Mo(CO)\(_2\)Cp]\(_2\) (3a, b) in the presence of [CP(CO)\(_3\)Mo]\(_2\). Due to the unusual mild conditions of aggregation the intermediate formation of the double bonded species Cp(CO)\(_2\)M = AsMe\(_2\) (2a, b) is postulated. The crystal structure of 3a is reported, which shows mutual trans arrangement of the cyclopentadienyl and CO ligands.
KW  - Chemie
Y1  - 1986
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31424
ER  - 
TY  - JOUR
A1  - Burschka, Christian
T1  - Die Kristallstruktur von p-Tolylbis(diethyldithiocarbamato)-thallium(III) und Phenylbis(methylxanthogenato)bismut(III)
T1  - Crystal Structure of p-Tolylbis(diethyldithiocarbamato)thallium(III) and Phenylbis(methylxanthogenato)bismut(III)
N2  - Die Kristallstruktur von 4.CH\(_3\)(C\(_6\)H\(_4\))-TI(S\(_2\)CN(C\(_2\)H\(_5\))\(_2\))\(_2\) (P2\(_1\)/c, a = 11,973(3) A, b = 10,692(3) A, c = 19,232(4) A, ß = 114,02(2)°, Z = 4) und C\(_6\)H\(_5\)-Bi(S\(_2\)COCH\(_3\))\(_2\) (P2\(_1\)/c, a = 6,395(2) A, b = 24,684(8) A, c = 9,732(3) A, ß = 101,38(3)°, Z = 4) konnte aus Röntgendiffraktometerdaten von Einkristallen ermittelt werden. Die interatomaren Abstände zeigen daß, die Koordination von Dithiocarbamat und Xanthogenat an die Metallatome wie schon vermutet stark asymmetrisch zweizähnig und ausschließlich über Schwefel erfolgt. Die Koordinationsunter· schiede zwischen Bismut und Thallium ergeben ein deutliches Indiz für die "stereochemische Aktivität" des freien Elektronenpaares am Bismutatom.
N2  - The crystal structure of 4.CH\(_3\)(C\(_6\)H\(_4\))-TI(S\(_2\)CN(C\(_2\)H\(_5\))\(_2\))\(_2\) ((P2\(_1\)/c, a = 11,973(3) A, b = 10,692(3) A, c = 19,232(4) A, ß = 114,02(2)°, Z = 4)  and C\(_6\)H\(_5\)-Bi(S\(_2\)COCH\(_3\))\(_2\) (P2\(_1\)/c, a = 6,395(2) A, b = 24,684(8) A, c = 9,732(3) A, ß = 101,38(3)°, Z = 4) was solved from X·ray diffraction data of single crystals. FlOm the interatomic distances follows that the dithiocarbamate and xantho· genate ligands coordinate asymmetrically bidentate to the metal as presumed and exclusively through the sulfur atoms. Differences in the coordination sphere of bismut and thallium give evidence for a "stereochemically active lone pair" on the bismut atom.
KW  - Chemie
Y1  - 1982
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31353
ER  - 
TY  - JOUR
A1  - Albert, Bernhard
A1  - Berning, Wilfried
A1  - Burschka, Christian
A1  - Hünig, Siegfried
A1  - Prokschy, Frank
T1  - Azobrücken aus Azinen, IV. Intramolekulare [2 + 2]-Photocycloaddition zwischen parallelen C = C- und N = N-Bindungen
T1  - Azo Bridges from Azines, IV.Intramolecular [2 + 2]-Photocycloaddition of Parallel C = C and N = N Bonds
N2  - In den starren Molekülen 1- 10 reagieren die benachbarten parallelen C = C- und N = N-Bindungen nahezu quantitativ unter Photocyclisierung lU den l,2-Diazetidinen 11-10, deren Struktur spektroskopisch und für 13 durch Kristallstrukturanalyse bewiesen wird. Die in Abwesenheit der C = C-Bindung beobachtete Photo-Denitrogenierung unterbleibt selbst bei den empfindlichen Derivaten des 2,3-Diazabicyclo[2.2.11heptens. Photocyclisierung von 6 mit lwei zur N=N· Bindung benachbarten C=C-Bindungen tritt nur mit der Norbornendoppelbindung ein.
N2  - The parallel C = C and N = N bonds in the rigid molecules 1- 10 photocyclile nearly quantitatively, forming l,2-diautidines 11-10. Their structure is confirmed by spectroscopic methods and for 13 by X-ray analysis. Radiation induced denitrogenation, the normal reaction for similar compounds without neighbouring C = C bonds, is suppressed even with the sensitive derivatives of 2,3-diazabicyclo[1.2.1)heptene. Photocyc1ization of 6, carrying two neighbouring C=C bonds, inc1udes only the norbornene bond.
KW  - Chemie
Y1  - 1984
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31314
ER  - 
TY  - JOUR
A1  - Strack, Fritz
A1  - Deutsch, Roland
T1  - Reflective and Impulsive Determinants of Social Behavior
N2  - This article describes a 2-systems model that explains social behavior as a joint function of reflective and impulsive processes. In particular, it is assumed that social behavior is controlled by 2 interacting systems that follow different operating principles. The reflective system generates behavioral decisions that are based on knowledge about facts and values, whereas the impulsive system elicits behavior through associative links and motivational orientations. The proposed model describes how the 2 systems interact at various stages of processing, and how their outputs may determine behavior in a synergistic or antagonistic fashion. It extends previous models by integrating motivational components that allow more precise predictions of behavior. The implications of this reflective–impulsive model are applied to various phenomena from social psychology and beyond. Extending previous dual-process accounts, this model is not limited to specific domains of mental functioning and attempts to integrate cognitive, motivational, and behavioral mechanisms.
KW  - Psychologie
KW  - dual-process models
KW  - dual-systems models
KW  - social cognition
KW  - reflective
KW  - impulsive
KW  - self regulation
Y1  - 2004
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-40447
ER  - 
TY  - JOUR
A1  - Burschka, Christian
T1  - CsCu\(_4\)S\(_3\) und CsCu\(_3\)S\(_2\) : Sulfide mit tetraedrisch und linear koordiniertem Kupfer
T1  - CsCu\(_4\)S\(_3\) and CsCu\(_3\)S\(_2\): Sulfides with Copper in Tetrahedral and Linear Coordination
N2  - No abstract available
KW  - Chemie
Y1  - 1980
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31366
ER  - 
TY  - JOUR
A1  - Burschka, Christian
A1  - Leonhard, K.
A1  - Werner, H.
T1  - Basische Metalle. XIV. Synthese und Kristallstruktur von C\(_5\)H\(_5\)(PMe\(_3\))CoS\(_5\) : Ein neuer Metallapentathia-Heterocyclus
T1  - Basic Metals. XIV. Synthesis and Crystal Structure of C\(_5\)H\(_5\)(PMe\(_3\))CoS\(_5\) : A New Metallapentathia Heterocycle
N2  - Der Zweikernkomplex C\(_5\)H\(_5\)(PMe\(_3\))Co(\(\mu\)-CO)\(_2\)Mn(CO)C\(_5\)H\(_4\)Me (8) reagiert mit stöchiometrischen Mengen S\(_8\) in praktisch quantitativer Ausbeute zu C\(_5\)H\(_5\)(PMe\(_3\))CoS\(_5\) (4). Der Koba.ltapentathia-Heterocyclus 4 ist ebenfalls aus C\(_5\)H\(_5\)(PMe\(_3\))Co(h\(^2\)-CS\(_2\)) (5) und S\(_8\) zugänglich. 4 kristallisiert monoklin mit den Gitterkonstanten a = 8,467(3) A, b = 12,128(4) A, c = 14,210(4) A und \(\beta\) = 102,20(2)°_ Die Sesselform des sechsgliedrigen CoS\(_5\)-Rings entspricht derjenigen in den bekannten Verbindungen (C\(_5\)H\(_5\))\(_2\)TiS\(_5\) und (C\(_5\)H\(_5\))\(_2\)VS\(_5\) , wobei in 4 der Cyclopentadienylligand die axiale und die Trimethylphosphingruppe die ä.quatoriale Position einnehmen.
N2  - The dinuclear complex C\(_5\)H\(_5\)(PMe\(_3\))Co(\(\mu\)-CO)\(_2\)Mn(CO)C\(_5\)H\(_4\)Me (8) reaots with stoichiometric amounts of S\(_8\) to form C\(_5\)H\(_5\)(PMe\(_3\))CoS\(_5\) (4) in practica.lly quantitative yields. The cobalt. apentathia heterocycle 4 is a.lso obtained by the reaction of C\(_5\)H\(_5\)(PMe\(_3\))Co(h\(^2\)-CS\(_2\)) (5) with S\(_8\), Cry. stals of 4 are monoclinic with a = 8.467(3) A, b = 12.128(4) A, c = 14.210(4) A and \(\beta\) = 102.20(2)°. The chair form of the six·membered CoS\(_5\) ringcorresponds to that of the compounds (C\(_5\)H\(_5\))\(_2\)TiS\(_5\) and (C\(_5\)H\(_5\))\(_2\)VS\(_5\) In 4, the cyclopentadienyl ligand occupies the axial and the trimethylphosphine group the equatorial position.
KW  - Chemie
Y1  - 1980
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31407
ER  - 
TY  - JOUR
A1  - Burschka, Christian
T1  - Intermolekulare Koordination bei zyklischen Esternder stibonigen und der thiostibonigen Säure
T1  - Intermolecular Coordination in Cyclic Esters of Stibonic Acid and Thiostibonic Acid
N2  - Die Struktur von EinkristalIen des 2-Methoxi-l,3, 2-benzodioxastibols und des 2-Methylthio-l, 3, 2-benzodithiastibols konnte über Röntgendiffraktometermessungen ermittelt werden. Die Verbindungen kristallisieren beide monoklin mit Elementarzellen, die jeweils 4 Formeleinheiten enthalten, sie sind jedoch nicht isomorph. Als Raumgruppe ergibt sich P21/n bzw. P21/c. Ungewöhnlich kurze intermolekulare Antimon-Chalkogen-Abstände lassen in der Struktur des Oxastibols koordinative Bindungen erkennen, die in dieser Stärke beim Thiastibol nicht auftreten.
N2  - The crystal structure of 2-methoxi-l,3,2-benzodioxastibole and of 2-methylthio- 1,3,2-benzodithiastibole was solved by X-ray diffraction methods. The compounds crystallize with monoclinic unit cells which contain 4 formula units each, they are, however, not isomorphou8. The space grol1p is P21/n and P21/c, respectively. Unusually short intermolecular antimony.-chalcogen distances revenl the existance of additional coordinative bonds within the structure of the oX3stiboJe which to such an extent cannot be observed within the corresponding thiastibole.
KW  - Chemie
Y1  - 1978
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31374
ER  - 
TY  - JOUR
A1  - Wieber, M.
A1  - Wirth, D.
A1  - Metter, J.
A1  - Burschka, Christian
T1  - Methylbis(dithiocarbamato)stibane : Synthese und Kristallstruktur.
T1  - Methylbis(dithiocarbamato)stibines : Synthesis and crystal structure
N2  - Die Titelverbindungen können durch Reaktion von Methyldibromstiban mit Natriumdithiocarbamaten bei tiefen Temperaturen (-78°C) erhalten werden. Bezüglich seiner Kristallstruktur läßt sich CH3Sb(S2CNEt2)2 gut zwischen dem entsprechenden Bismutan CH3Bi(S2CNEt2)2 und dem Arsan C6H5As(S2CNEt2)2 einordnen. Anzeichen für ungewöhnliche intermolekulare Wechselwirkungen sind bei dieser Verbindung nicht zu erkennen.
N2  - The title compounds are obtained by reaction of methyldibromostibane with the sodium dithiocarbamates in methanol at low temperature (-78°C). The crystalstructure of CH3Sb(S2CNEt2)2 as elucidated by X-ray diffraction shows no special intermolecular interactions. It can be compared to that of the corresponding bismutane CH3Bi(S2CNEt2)2 and the arsane C6H5As(S2CNEt2)2.
KW  - Chemie
Y1  - 1985
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31949
ER  - 
TY  - JOUR
A1  - Scheer, Ulrich
T1  - Structure of lampbrush chromosome loops during different states of transcriptional activity as visualized in the presence of physiological salt concentrations
N2  - Lampbrush chromosomes of amphibian oocytes were isolated in the presence of near-physiological salt concentrations, to preserve their native state, and studied by electron microscopy of ultrathin s~dions. The transcriptional state of the lampbrush chromosomes was experimentally modulated by incubating the oocytes for various time periods in medium containing actinomycin D. The observations show that the structure of the lateral loops changes rapidly in response to alterations in transcriptional activity. During decreasing transcriptional activity and reduced packing density of transcripts, the chromatin axis first condensed into nucleosomes and then into an approximately 30 nm thick higher order chromatin fiber. Packaging of the loop axis into supranucleosomal structures may contribute to the foreshortening and retraction of the loops observed during inhibition of transcription and in later stages of meiotic prophase. The increasing packing density of the DNA during the retraction process of the loops could also be visualized by immunofluorescence microscopy using antibodies to DNA. The dependence of the loop chromatin structure on transcriptional activity is discussed in relation to current views of mechanisms involved in gene activation.
KW  - lampbrush chromosomes
KW  - chromatin structure
KW  - electron microscopy
KW  - immunofluorescence microscopy
KW  - DNA antibodies
Y1  - 1987
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39304
ER  - 
TY  - JOUR
A1  - Thiry, Marc
A1  - Scheer, Ulrich
A1  - Goessens, Guy
T1  - Localization of DNA within Ehrlich tumour cells nucleoli by immunoelectron microscopy
N2  - The distribution of DNA in Ehrlich tumour cell nucleoli was investigated by means of an immunocytochemical approach , involving a monoclonal antibody directed against double- and single-stranded DNA. Immunolabelling was performed . either before or after the embedding process. The postembedding labelling method allows better ultrastructural preservation than the preembedding labelling method. In particular, the various nucleolar components are well preserved and identifiable. In the nucleolus, labelling is particularly concentrated over the perinucleolar chromatin and over its intranucleolar invaginations, which penetrate the nucleolar body and often terminate at the fibrillar centres. In addition, aggregates of gold particles are found in the fibrillar centres, preferentially towards the peripheral regions. By contrast, the dense fibrillar component is completely devoid of labelling. The results seem to indicate that DNA containing the rDNA genes is located in the fibrillar centres, with a preference for the peripheral regions. This finding suggests that transcription of the rDNA genes should occur within the confines of the fibrillar centre, probably close to the boundary region of the surrounding dense fibrillar component. The results are discussed in the light of present knowledge of the functional organization of the nucleolus.
KW  - nucleolus
KW  - DNA
KW  - monoclonal antibody
Y1  - 1988
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39327
ER  - 
TY  - JOUR
A1  - Benavente, Ricardo
A1  - Schmidt-Zachmann, Marion S.
A1  - Hügle-Dörr, B.
A1  - Reimer, G.
A1  - Rose, K. M.
A1  - Scheer, Ulrich
T1  - Identification and definition of nucleolus-related fibrillar bodies in micronucleated cells
N2  - Small nucleolus-related bodies which occur in the nUcleoplasm of " micronuclei" lacking nucleolar organizers have been studied by immunofluorescence microscopy. These bodies stained specifically with three different antibodies directed against proteins that are normally associated with the dense fibrillar component of functional nucleoli, but not with antibodies specific for certain proteins of the granular component or the fibrillar centers. Our data show that, in the absence of rRNA genes, the various constituent proteins characteristic of the dense fibrillar component spontaneously assemble into spherical entities but that the subsequent fusion of these bodies into larger structures is prevented in these micronuclei. The similarity between these nucleolus-related bodies of micronuclei and the prenucleolar bodies characteristic of early stages of nucleologenesis during mitotic telophase is discussed.
Y1  - 1988
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39423
ER  - 
TY  - JOUR
A1  - Knecht, Sigrid
A1  - Scheer, Ulrich
T1  - Lautäußerung und Verhalten des Azoren-Buchfinken (Fringilla coelebs moreletti Pucheran)
N2  - Einleitung und Methode S. 155. - Brutbiologie S. 155. - Motivgesang S. 157. - Sozialruf (Social Call) S. 161. - Entwicklung des Sozialrufs S. 164. - Brumimmungsruf (Regenruf) S. 165. - Flugruf S. 166. - Alarmruf eines Jungvogels S. 167. - Bestimmung der ReviergroBe S. 167. - Zusammenfassung S. 168. - Summary S. 168. - Literaturverzeichnis S. 169. Es wird untersucht, ob die Azoren-Buchfinken "Rassengesang" und "Rassenrufe" haben. Gesange und Rufe wurden auf Tonband aufgenommen und klangspek trogra phiert. Motivgesang. Jedes cJ beherrscht 2-6 verschiedene Gesangsformen, wobei stets eine "Alltagsform" mit der stark vereinfachten Phrase di-djah endigt. Die anderen, weniger haufigeren Gesangsformen ("Sonntagsformen") zeigen eine besser ausgearbeitete Endphrase, die jedoch nie so kompliziert wie bei kontinentalen Buchfinken ist. In Gebieten, in denen sich bevorzugt Kanarienvogel aufhalten, konnen Buchfinken Gesangselemente iibernehmen. Sozialruf. Das kontinentale pink ist auf alIen Azoreninseln durch ga ersetzt, so daB man von einem Rassenruf sprechen kann. Er ist mit starker Aggressionsneigung verkniipft. Der Sozialruf zeigt einen weiten Frequenzumfang, hervorgerufen durch mehrere simultane Noten. Brutstimmungsruf (Regenruf). Eine Anzahl verschiedener Rufe wurde spektrographiert. Vom cJ ist er bei maBiger Gefahr, aber auch spontan (30-70 Rufe/Min.) zu horen. Flugruf. Er scheint mit dem Flugruf der Nominatform identisch zu sein. Bestimmung der Reviergrope. Ein cJ wurde innerhalb seines Reviers an die "akustische Leine" genommen und bis zu den Reviergrenzen gezogen. Verhalten und LautauBerung anderten sich in Abhangigkeit von der jeweiligen Entfernung bis zur Reviergrenze.
N2  - The attempt was made to determine whether Azores chaffinches possess a "racial song" or "racial calls". The songs and calls were tape-recorded and sound-spectrographs were prepared. 1. The song motif. Each cJ possesses 2-6 different song types, among which there is an "everyday type" which always ends with the greatly simplified phrase: dee-chah. The other, less frequent song types ("Sunday types") exhibit a more developed final phrase, though this is not as complex as that of Continental chaffinches. In areas where canaries commonly occur, chaffinches may adopt some of their song elements. 2. The social call. The Continental pink is replaced by gai in all of the Azores island forms, so it is justifiable to speak of a "racial call". This call is correlated with a strong aggressive tendency; it exhibits a broad frequency range based upon simultaneous utterance of several notes. 3. The brooding call ("rain-call"). A number of different calls were spectrographed. With the cJ, this call can be heard in response to mild danger and also as a spontaneous utterance (30-70 calls /min.). 4. Flight call. This seems to be identical to the flight call of the nominate type. 5. Determination of territory size. A cJ was led within his territory on an "acoustical lead" and drawn to his territorial boundaries. His. behaviour and vocalizations altered in relation to the distance from the territorial boundary.
KW  - Tierpsychologie
Y1  - 1968
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39479
ER  - 
TY  - JOUR
A1  - Franke, Werner W.
A1  - Scheer, Ulrich
A1  - Herth, Werner
T1  - Cytology, general and molecular cytology
N2  - The present article had originally been conceived as a review on endomembranes, the plasma membrane, and the major product of membrane-bound activities, the cell wall material. However, limitations of space and the cascading number of pertinent literature articles made it necessary to confine this to one group of membranes and one type of cell wall components. Therefore, we shall begin our survey on the biochemical and cytological aspects of membranes by a review of the class of the pore complex bearing endomembranes, i.e. the nuclear envelope and the annulate lamellae (AL). Next year the membranes of the endoplasmic reticulum and the dictyosomes will be dealt with in conjunction with a discussion of the various intracellular vesicles, the tonoplast and the plasmalemma.
KW  - Botanik
Y1  - 1974
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39499
ER  - 
TY  - JOUR
A1  - Scheer, Ulrich
T1  - The ultrastructure of the nuclear envelope of amphibian ooctyes: IV. On the chemical nature of the nuclear pore complex material
N2  - In order to investigate the chemical composition of the nuclear pore complexes isolated nuclei from mature Xenopus laevis oocytes were manually fractioned into nucleo· plasmic aggregates and the nuclear envelopes. The whole isolation procedure takes no more than 60- 90 sec, and the pore complexes of the isolated envelopes are well preserved as demonstrated by electron microscopy. Minor nucleoplasmic and cytoplasmic contaminations associated with the isolated nuclear envelopes were determined with electron microscopic morphometry and were found to be quantitatively negligible as far as their mass and nucleic acid content is concerned. The RNA content of the fractions was determined by direct phosphorus analysis after differential alkaline hydrolysis. Approximately 9% of the total nuclear RNA of the mature Xenopus egg was found to be attached to the nuclear envelope. The nonmembranous elements of one pore complex contain 0.41 X 10- 16 g RNA. This value agrees well with the content estimated from morphometric data. The RNA package density in the pore complexes (270 X 10- 15 g/fJ-3) is compared with the nucleolar, nucleoplasmic and cytoplasmic RNA concentration and is discussed in context with the importance of the pore complexes for the nucleo-cytoplasmic transport of RNA-containing macromolecules. Additionally, the results of the chemical analyses as well as of the 3H-actinomycin D autoradiography and of the nucleoprotein staining method of Bernhard (1969) speak against the occurence of considerable amounts of DNA in the nuclear pore complex structures.
KW  - Nuclear envelope
KW  - Amphibian oocytes
KW  - Nuclear pore complex
KW  - Chemical nature
KW  - Electron microscopy
Y1  - 1972
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39500
ER  - 
TY  - JOUR
A1  - Franke, Werner W.
A1  - Kartenbeck, Jürgen
A1  - Krien, S.
A1  - VanderWoude, W. J.
A1  - Scheer, Ulrich
A1  - Morré, D. J.
T1  - Inter- and intracisternal elements of the Golgi apparatus: A system of membrane-to-membrane cross-links
N2  - Electron opaque cross-bridge structures span the inter- and intracisternal spaces and provide membrane-to-membrane connections between adjacent cisternae of dictyosomes of pollen tubes of Clivia and Lilium. Additionally, the classic intercisternal rods, characteristic of intercisternal regions near the maturing face of dictyosomes, are connected with the adjacent membranes through similar cross-bridge elements. We suggest that these structural links are responsible for maintaining the flattened appearance of the central parts of Golgi apparatus cisternae as well as for the coherence of cisternae within the stack. Observations on other plant (e.g. microsporocytes of Canna) and animal cells (e.g. rodent liver and hepatoma cells, newt spermatocytes) show that such an array of membrane cross-links is a universal feature of Golgi apparatus architecture. The cross-bridges appear as part of the complex "zone of exclusion" which surrounds dictyosomes, entire Golgi apparatus and Golgi apparatus equivalents in a variety of cell types.
KW  - Golgi apparatus
KW  - Membranes
KW  - Cross-bridges
KW  - Electron microscopy
Y1  - 1972
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39514
ER  - 
TY  - JOUR
A1  - Scheer, Ulrich
A1  - Kartenbeck, Jürgen
A1  - Trendelenburg, Michael F.
A1  - Stadler, Joachim
A1  - Franke, Werner W.
T1  - Experimental disintegration of the nuclear envelope: evidence for pore-connecting fibrils
N2  - The disintegration of the nuclear envelope has been examined in nuclei and nuclear envelopes isolated from amphibian oocytes and rat liver tissue, using different electron microscope techniques (ultrathin sections and negatively or positively stained spread preparations). Various treatments were studied, including disruption by surface tension forces, very low salt concentrations, and non ionic detergents such as Triton X-lOO and Nonidet P-40. The high local stability of the cylinders of nonmembranous pore complex material is emphasized. As progressive disintegration occurred in the membrane regions, a network of fibrils became apparent which interconnects the pore complexes and is distinguished from the pore complexassociated intranuclear fibrils. This network might correspond to an indistinct lamella, about 15 - 20 nm thick, located at the level of the inner nuclear membrane, which is recognized in thin sections to bridge the interpore distances. With all disintegration treatments a somewhat higher susceptibility of the outer nuclear membrane is notable, but a selective removal does not take place. Final stages of disintegration are generally characterized by the absence of identifiable, membrane- like structures. Analysis of detergent-treated nuclei and nuclear membrane fractions shows almost complete absence of lipid components but retention of significant amount of glycoproteins with a typical endomembrane-type carbohydrate pattern. Various alternative interpretations of these observations are discussed. From the present observations and those of Aaronson and Blobel (1,2), we favor the notion that threadlike intrinsic membrane components are stabilized by their attachment to the pore complexes, and perhaps also to peripheral nuclear structures, and constitute a detergent-resistant, interpore skeleton meshwork.
Y1  - 1976
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39735
ER  - 
TY  - JOUR
A1  - Trendelenburg, Michael F.
A1  - Scheer, Ulrich
A1  - Franke, W. W.
T1  - Structural organization of the transcription of ribosomal DNA in oocytes of the house cricket
N2  - No abstract available
Y1  - 1973
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-33113
ER  - 
TY  - JOUR
A1  - Scheer, Ulrich
A1  - Raska, I.
T1  - Immunocytochemical localization of RNA polymerase I in the fibrillar centers of nucleoli
N2  - No abstract available
Y1  - 1987
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39618
ER  - 
TY  - JOUR
A1  - Fischer, Dagmar
A1  - Hock, Robert
A1  - Scheer, Ulrich
T1  - DNA Topoisomerase II is not detectable on lampbrush chromosomes but enriched in the amplified nucleoli of xenopus oocytes
N2  - In somatic cells DNA topoisomerase II (topo II) is thought to be involved in the domain Organization of the genome by anchoring the basis of chromatin loops to a chromosomal scafFold. Lampbrush chromosomes of am-phibian oocytes directly display this radial loop Organization in cytological preparations. In order to find out whether topo II may play a role in the Organization of these meiotic chromosomes, we performed immunofluorescence studies using antibodies against Xenopus topo II. Our results indicate that topo II is apparently absent from lampbrush chromosomes and is hence unlikely to act as a "fastener" of the numerous lateral chromosomal loops. Topo II was, however, enriched in the amplified nucleoli of Xenopus oocytes.
Y1  - 1993
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-32654
ER  - 
TY  - JOUR
A1  - Franke, Werner W.
A1  - Scheer, Ulrich
T1  - Structural details of dictyosomal pores
N2  - Structural details of the dictyosomal pores in several plant cell types are described from tangential and cross sections of Golgi cisternae. Frequency distributions of the sizes of such Golgi pores are given and compared with the corresponding values of nuclear pores in the same cells. Golgi pore inner diameters are less homogeneously distributed and can be as small as 100 A or less. They are not simply cisterna I holes, but are often associated with centrally located electron dense granules or rods and with inner pore filaments. This organization, which is very common in dictyosomal pores in plant and animal cells, has some similarities with the structural architecture of nuclear envelope and annulate lamellar pore complexes. The particulate material associated with the dictyosomal pores shows spatial and structural relationship to cytoplasmic ribosomes. Possible modes of Golgi pore formation and some consequences of these observations for interpretation of nuclear pore structures are discussed.
Y1  - 1972
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-32155
ER  - 
TY  - JOUR
A1  - Scheer, Ulrich
T1  - Biologische Objekte im Transmissions-Elektronenmikroskop (Teil 4): Spreitungstechniken
N2  - Visualizing nucleic acids (DNA, RNA), nucleoprotein complexes and chromatin requires the use of special electron microscopicspreading techniques. In part 4 (27 refs.), methods are outlined for spreading DNA and RNA molecules for electron microscopic observation, these methods using modifications of the basic protein film method developed by A. Kleinschmidt and R. K. Zahn (1959). Hybridization techniques that allow the observation of heteroduplexes formed between two DNA molecules or between DNA and RNA molecules are reviewed, with special emphasis being placed on the DNA-RNA hybrids as a tool for elucidating RNA splicing. Techniques for studying DNA-protein interactions without the use of a protein monolayer film are mentioned. Finally, the "Miller spreading technique" for visualizing the nucleosomal organization of eukaryotic chromatin as well as the transcription of genes is discribed and illustrated.
Y1  - 1982
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39652
ER  - 
TY  - JOUR
A1  - Scheer, Ulrich
A1  - Knecht, Sigrid
T1  - Die Vögel der Azoren
T1  - The birds of the Azores
N2  - Während einer viermonatigen Reise zu allen neun Azoreninseln wurde der gesamte Brutvogelbestand dieses Archipels untersucht. Die Befunde sind in einer detaillierten Artenliste zusammengefaßt, ergänzt durch ökologische und brutbiologische Anmerkungen. Zahlreiche Beobachtungen lassen vermuten, daß vor allem Stieglitz und Kanarienvogel tägliche und auch jahreszeitlich bedingte interinsulare Flüge unternehmen. Die Lautäußerungen sechs verschiedener Vogel arten sind in Klangspektrogrammen dargestellt. Ein mathematischer Ansatz zeigt, daß sich die Anzahl der auf einer bestimmten Insel brütenden Landvogelarten umgekehrt proportional zur Entfernung zum europäischen Festland und proportional zum Logarithmus naturalis der Inselfläche verhält. Die abgeleitete Formel läßt sich prinzipiell auch auf andere Atlantikinseln anwenden, die weitgehend vom Festland isoliert sind.
N2  - Observations of the breeding birds were performed during a four months journey of the nine Azores islands. The data are summed up in a detailed species-list supplemented by ecological notes as weIl as some comments upon the breeding behaviour. Several findings suggest that goldfinch and canary undertake daily and also seasonal flights between the islands. Songs and calls of six different species are represented in sound-spektrographs. A mathematical analysis shows that the species number of the breeding land birds of a certain island is indirectIy proportional to the distance between the island and the european continent and directly proportional to the natural logarithm of the island area. The deduced formula is also principly applicable for other atlantic islands which are largely iso la ted from the continent.
Y1  - 1971
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39668
ER  - 
TY  - JOUR
A1  - Franke, Werner W.
A1  - Scheer, Ulrich
A1  - Spring, Herbert
A1  - Trendelenburg, Michael F.
A1  - Krohne, G.
T1  - Morphology of transcriptional units of rDNA: evidence for transcription in apparent spacer intercepts and cleavages in the elongating nascent RNA
N2  - Several types of "irregular" structures in the arrangement of lateral fibrils were noted in electron microscopic preparations of transcriptionally active nucleolar chromatin from various plant and animal cells. Such forms include: I. Disproportionately long lateral fibrils which occur either as individual fibrils or in groups; 2. "Prelude complexes" and other arrangements of lateral fibrils in apparent spacer intercepts; 3. Thickening of the rDNA chromatin axis at the starting end of pre-rRNA matrix units; 4. Extremely long matrix units , the length of which exceeds that of the rDNA (double-strand) sequence complementary to the specific pre-rRN A (for abbreviations see text). In addition, the stability of high molecular weight RNAs contained in the nucleolar ribonucleoproteins during the preparation for electron microscopy was demonstrated by gel electrophoresis. The observations indicate that the morphological starting point of a pre-rRNA matrix unit is not necessarily identical with the initiation site for synthesis of pre-rRNA, but they rather suggest that the start of the transcriptional unit is located at least O.2-D.8 JLm before the matrix unit and that parts of the "apparent spacer" are transcribed. It is proposed that the pre-rRN A molecules do not represent the primary product of rDNA transcription but rather relatively stable intermediate products that have already been processed during transcription.
Y1  - 1976
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39681
ER  - 
TY  - JOUR
A1  - Linsenmair, Karl Eduard
T1  - Untersuchungen zur Soziobiologie der Wüstenassel Hemilepistus reaumuri und verwandter Isopodenarten (Isopoda, Oniscoidea): Paarbildung und Evolution der Monogamie
T1  - On the sociobiology of the desert isopod Hemilepistus reaumuri, and related species: pairbond and evolution of monogamy
N2  - The desert isopod, Hemilepistus reaumuri, extremely common in the arid regions of North Africa and Asia Minor, depends upon the burrows it itself digs for survival during the hotter parts of the year. The dig-ging of new burrows is limited by chmatic conditions to a short period during the spring. Burrows must be constantly defendet - especially against roving eonspecifics. The decisive problem of a connnuous burrow defense is solved through cooperative behavior: the adult woodlice form monogamous pairs whose partners recognize one another individually. Here, questions on the binding of partners, especially the problem of the binding of male to female will be treated upon, along with questions on the evolution of monogamy, wherein the purely maternal families of Porcellio species will be taken as models for intermediäre stages. At first, males olHemilepistus are not permitted to copulate at all; later, for a relatively long period, they are only permitted incomplete copulations, the females alone have control over the partunal ecdysis; they alone determine the moment of final copulations. Under the thermal conditions prevalent during the season of pair formation, a female irreversibly induces a parturial ecdysis only when it has spent a minimum of sev-eral days in her own burrow with a specific male. At higher average temperatures, the number of females which undergo parturial ecdyses without these preconditions increases sharply. Males cannot greatly lnrlu-ence the willingness of females to reproduce with the investment they make in the digging of burrows; the factors deciding this are the male's presence and its role as guard. The first condition necessary for the genesis of monogamy might have been the evolution of a stncüy lo-cation-dependent copulatory behavior, which guaranteed the male exclusive mating pnveliges with the female whose location - the burrow - he acheived control of. A male must, under these conditions, serve guard duty in his own interest, and defend the burrow against competitors (Cf or 2) seeking an already-dug burrow. The decisive advantage for the female in the beginning of the development was probably that she could leave the burrow for extended feeding excursions, whereas alone it would have to either completely forego nourishment or, as is the case with the Porcellio species mentioned, must greatly restrict the spectrum of food that it can use (to that which is to be found only a short distance from the burrow and which can eas-ily be carried inside the burrow). This could be a disadvantage, especially during egg production. Necessary to the male's successful defense of the burrow is that he recognises his female. Studies of the Canary Island Porcellio species have shown over which pathways and under what selection pressures the recopinon of individuals, as is realized mHemilepistus, could have evolved. Females can bind males longer, the longer the period of their attraction is extended: Females olHemilepistus reaumuri have been proven to be al·ready att-ractive before they are ready to copulate and still remain attractive after they have copulated. The conse-quences of the last fact will be discussed. The question of why the males remain with the females after the parturial ecdysis will also be discussed: The great danger to the male's investment resulting from a tooi early abandoning, and the low probability of successfully finding another partner after a later abandomng should prevent a positive balance in the males' cost-effecriveness calculations.
Y1  - 1979
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-30854
ER  - 
TY  - JOUR
A1  - Bringmann, Gerhard
A1  - Zagst, Rainer
A1  - Schöner, Bernd
A1  - Busse, Holger
A1  - Hemmerling, Martin
A1  - Burschka, Christian
T1  - Acetogenic Isoquinoline Alkaloids. XXIII. Structure of the Naphthyl Isoquinoline Alkaloid Dioncophylline A
N2  - No abstract available
KW  - Chemie
Y1  - 1991
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31331
ER  - 
TY  - JOUR
A1  - Albert, Bernhard
A1  - Berning, Wilfried
A1  - Burschka, Christian
A1  - Hünig, Siegfried
A1  - Martin, Hans-Dieter
A1  - Prokschy, Frank,
T1  - Transanulare Wechselwirkung des Azo-Chromophors inisodrinanalogen Systemen
T1  - Transanular Interactions of the Azo Chromophore in Isodrin-type Systems
N2  - No abstract available
KW  - Chemie
Y1  - 1981
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31328
ER  - 
TY  - JOUR
A1  - Fiala, Brigitte
A1  - Linsenmair, Karl Eduard
A1  - Maschwitz, Ulrich
T1  - Diversität von Interaktionen zwischen Ameisen und Pflanzen im südostasiatischen Regenwald
T1  - Diversity of ant-plant interactions in south-east Asian rainforests
N2  - Assoziationen von Ameisen mit Pflanzen (und oft noch mit pflanzensaugenden Insekten als drittem Partner) dürften eine Ursache des Artenreichtums und der hohen Abundanzen tropischer Formicidae sein. Die von den Ameisen genutzten Pflanzen bieten entweder Nahrung an, über extraflorale Nektarien und/oder Nährkörperchen, oder aber - bei den eigentlichen Myrmekophyten - Nistraum und z.T. auch Nahrung. Diese Beziehungen zeichnen sich durch unterschiedliche Nutzungsweisen und Nutzungsintensitäten und damit stark differierende Abhängigkeit der Partner voneinander aus. Ein besonders breites Spektrum von Ameisen-Pflanzen-Assoziationen finden wir in der paläotropischen Baumgattung Macaranga (Euphorbiaceae), die sich daher als Modellsystem für vergleichende Untersuchungen hervorragend eignet. Die Grundfrage unserer Untersuchungen an diesem System lautet: Verläuft aufgrund der ausgeprägt mosaikartigen Verteilung der von den myrmekophilen Pflanzen angebotenen Nahrungs- und Nistraumressourcen die Neu- und Wiederbesiedlung von Habitaten durch die Ameisen in Form von Zufallsprozessen? Oder werden, im Gegenteil, durch diesen Umstand Spezialisierungen seitens der Ameisen gefördert und die Zusammensetzung der Lebensgemeinschaften dadurch stärker deterministisch geprägt? Unsere bisherigen Untersuchungen zeigen, daß beide Prinzipien wirken. Bei der alleinigen Nutzung von Nahrungsressourcen fehlen spezialisierte Beziehungen weitgehend und stochastische Ereignisse dürften sehr häufig die Pflanzen-Ameisen-Assoziation bestimmen. Bei den eigentlichen Myrmekophyten hingegen ist die Auswahl der assozierten Ameisen viel stärker determiniert, ganz besonders dann, wenn der Wohnraum, den die Pflanze offeriert, nur durch aktives Öffnen seitens der Ameisen erschlossen werden kann.
N2  - Associations of ants with plants can be regarded as one reason for the high abundance and diversity of ants in the tropics. The plants either provide food as extrafloral nectar and/or food bodies or, in the true myrmecophytes, nesting space and partly also food. These associations are characterized by very different forms and intensities of use of the plant resources and, therefore, also varying mutual dependency of the partners. A broad spectrum of different ant-plant associations is found in the paleotropical tree genus Macaranga (Euphorbiaceae) wh ich is therefore especially suited as a model system for a comparative investigation. The central question of our studies is: Does the mosaic character of the spatial distribution of food and nesting resources provided by the myrmecophilous plants rather favour stochastic processes during colonization of habitats by ants? Or does it, on the contrary, preferentially lead to strong specializations in the ants? Our investigations show that both principles are realized. In interactions where ants only use the food resources, specific relationships are lacking and stochastic events direct the associations. In obligate myrmecophytes, however, the colonization largely follows deterministic principles, especially when nesting space inside the plant actively has to be made accessible by the ants.
Y1  - 1994
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-32894
ER  - 
TY  - JOUR
A1  - Scheer, Ulrich
A1  - Sommerville, John
A1  - Müller, Ulrike
T1  - DNA is assembled into globular supranucleosomal chromatin structures by nuclear contents of amphibian oocytes
N2  - The assembly of DNA into nucleosomal and supranucleosomal chromatin structures has been studied (i) by injection of circular DNA molecules (plasmids) into nuclei of Pleurodeles waltlii oocytes; and (ii) by in vitro incubation of plasmid molecules with the supernatant fraction from oocyte nuclei of Pleurodeles and Xenopus laevis, followed by purification of nucleoprotein structures formed with sucrose gradient centrifugation. [n both types of experiments , spread preparations of the newly assembled and transcriptionally inactive chromatin , examined by electron microscopy , show dense globular higher order (supranucleosomal) packing forms. Under partially relaxing (low salt) preparation conditions granular chromatin subunits of about 30 nm diameter can be seen either as widely spaced particles or in closely packed aggregates. The transcriptionally inactive endogenous chromatin of chromomeres of lampbrush chromosomes is arranged in similar higher order chromatin units. A correlation is found between the sizes of the DN A molecule probes used and the numbers of nucleosomes and higher order globules in the assembled chromatin structures. After prolonged dispersion in low salt buffers , these globular chromatin units unfold into chains of7-12 nucleosomes. The results support the concept that chromatin is arranged , under physiological ion concentrations as they are present in the nucleus , in supranucleosomal units of globular morphology.
Y1  - 1980
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39671
ER  - 
TY  - JOUR
A1  - Hügle, Barbara
A1  - Hazan, Rachel
A1  - Scheer, Ulrich
A1  - Franke, Werner W.
T1  - Localization of ribosomal protein S1 in the granular component of the interphase nucleolus and its distribution during mitosis
N2  - Using antibodies to various nucleolar and ribosomal proteins, we define, by immunolocalization in situ, the distribution of nucleolar proteins in the different morphological nucleolar subcompartments. In the present study we describe the nucleolar localization of a specific ribosomal protein (51) by immunofluorescence and immunoelectron microscopy using a monoclonal antibody (R5 1-105). In immunoblotting experiments, this antibody reacts specifically with the largest and most acidic protein of the small ribosomal subunit (51) and shows wide interspecies cross-reactivity from amphibia to man. Beside its localization in cytoplasmic ribosomes, this protein is found to be specifically localized in the granular component of the nucleolus and in distinct granular aggregates scattered over the nucleoplasm. This indicates that ribosomal protein 51, in contrast to reports on other ribosomal proteins, is not bound to nascent pre-rRNA transcripts but attaches to preribosomes at later stages of rRNA processing and maturation. This protein is not detected in the residual nucleolar structures of cells inactive in rRNA synthesis such as amphibian and avian erythrocytes. During mitosis, the nucleolar material containing ribosomal protein 51 undergoes a remarkable transition and shows a distribution distinct from that of several other nucleolar proteins. In prophase, the nucleolus disintegrates and protein 51 appears in numerous small granules scattered throughout the prophase nucleus. During metaphase and anaphase, a considerable amount of this protein is found in association with the surfaces of all chromosomes and finely dispersed in the cell plasm. In telophase, protein 51-containing material reaccumulates in granular particles in the nucleoplasm of the newly formed nuclei and, finally, in the re-forming nucleoli. These observations indicate that the nucleolus-derived particles containing ribosomal protein 51 are different from cytoplasmic ribosomes and, in the living cell, are selectively recollected after mitosis into the newly formed nuclei and translocated into a specific nucleolar subcompartment, i.e ., the granular component. The nucleolar location of ribosomal protein 51 and its rearrangement du'ring mitosis is discussed in relation to the distribution of other nucleolar proteins.
KW  - Cytologie
Y1  - 1985
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39695
ER  - 
TY  - JOUR
A1  - Scheer, Ulrich
A1  - Hinssen, Horst
A1  - Franke, Werner W.
A1  - Jockusch, Brigitte M.
T1  - Microinjection of actin-binding proteins and actin antibodies demonstrates involvement of nuclear actin in transcription of lampbrush chromosomes
N2  - Nuclei of amphibian oocytes contain large amounts of actin, mostly in unpolymerized or short-polymer form. When antibodies to actin or actin-binding proteins (fragmin and the actin modulator from mammalian smooth muscle) are injected into nuclei of living oocytes of Pleurodeles waltlii, transcription of the lampbrush chromosomes, but not of the rRNA genes, is inhibited. When transcription is repressed by drugs or RNA is digested by microinjection of RNAase into oocyte nuclei, an extensive meshwork of actin filament bundles is seen in association with the isolated lampbrush chromosomes. These observations indicate a close relationship between the state of nuclear actin and transcriptional activity and suggest that nuclear actin may be involved in transcriptional events concerning protein-coding genes.
Y1  - 1984
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39706
ER  - 
TY  - JOUR
A1  - Scheer, Ulrich
A1  - Hansmann, Paul
A1  - Falk, Heinz
A1  - Sitte, Peter
T1  - Ultrastructural localization of DNA in two Cryptomonas species by use of a monoclonal DNA-antibody
N2  - Immunogold cytochemistry - DNA localization - Cryptomonas nucleomorph The distribution and subcellular localization of DNA in the unicellular alga Cryptomonas has been investigated electron-microscopically by indirect immunocytochemistry, using a monoclonal DNA antibody and a gold-Iabeled secondary antibody. This technique proved to be very sensitive and entirely specific. DNA could be demonstrated in four different compartments (nucleus, nucleomorph, plastid, and mitochondrion). Within the plastid, DNA is concentrated in stroma regions that are localized preferentially around the center of the organelle. The mitochondrion contains several isolated DNA-containing regions (nucleoids). Within the nucleus, most of the DNA is localized in the 'condensed' chromatin. DNA was also detectable in small areas of the nucleolus, whereas the interchromatin space of the nucleus appeared almost devoid of DNA. Within the nucleomorph, DNA is distributed inhomogeneously in the matrix. DNA could furthermore be detected in restricted areas of the 'fibrillogranular body' of the nucleomorph, resembling the situation encountered in the nucleol us. The presence of DNA and its characteristic distribution in the nucleomorph provide additional, strong evidence in favour of the interpretation of that organelle as the residual nucleus of a eukaryotic endosymbiont in Cryptomonas.
KW  - Cytologie
Y1  - 1986
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39746
ER  - 
TY  - JOUR
A1  - Scheer, Ulrich
T1  - Changes of nucleosome frequency in nucleolar and non-nucleolar chromatin as a function of transcription: an electron microscopic study
N2  - The morphology of nucleolar and non-nucleolar (Iampbrush chromosome loops) chromatin was studied in the electron microscope during states of reduced transcriptional activity in amphibian oocytes (Xenopus laevis, Triturus alpestris, T. cristatus). Reduced transcriptional activity was observed in maturing stages of oocyte development and after treatment with an inhibitor, actinomycin D. Strands of nucleolar chromatin appear smooth and thin, and contain only few, if any, nucleosomal particles in the transcribed units. This is true whether they are densely or only sparsely covered with lateral ribonucleoprotein fibrils. This smooth and non-nucleosomal character is also predominant in the interspersed, apparently nontranscribed rDNA spacer regions. During inactivation, however, nucleolar chromatin frequently and progressively assumes a beaded appearance in extended fibril-free-that is, apparently nontranscribed - regions. I n either fUll-grown 00- cytes or late after drug treatment, most of the nucleolar chromatin is no longer smooth and thin, but rather shows a beaded configuration indistinguishable from inactive non - nucleolar chromatin. In many chromatin strands, transitions of fibril-associated regions of smooth character into beaded regions wihout lateral fibrils are seen. Similarly, in the non-nucleolar chromatin of the retracting lampbrush chromosome loops, reduced transcriptional activity is correlated with a change from smooth to beaded morphology. Here, however, beaded regions are also commonly found interspersed between the more or less distant bases of the lateral fibrils, the putative transcriptional complexes. I n both sorts of chromatin, detergents (in particular Sarkosyl) that remove most of the chromatin proteins including histones from the DNA axis but leave the RNA polymerases of the transcriptional complexes attached were used to discriminate between polymerases and nucleosomal particles. The results suggest that nucleosomes are absent in heavily transcribed chromatin regions but are reformed after inactivation. In contrast to the findings with inactivated nucleolar genes, in lampbrush chromosome loops the beaded nucleosomal configuration appears to be assumed also in regions within transcriptional units that, perhaps temporarily, are not involved in transcription.
Y1  - 1978
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39750
ER  - 
TY  - JOUR
A1  - Scheer, Ulrich
A1  - Sommerville, J.
T1  - Structural organization of nascent transcripts and hnRNA molecules in amphibian oocytes
N2  - Comparisons ofrelative lengths oflampbrush loops, nascent RNP transcripts and hnRNA molecules from oocytes of amphibia with different C-values show that there is an increasing trend in loop, and transcriptional unit, length with increase in genome size but no increasing trend with respect to RN A contour length.The formation of duplex regions and circles in RNP fibrils indicates that RNA processing may occur within the nascent fibrils. The hnRNA molecules from oocytes of the various amphibia readily form intermolecular duplex structures. These complementary sequences have a low kinetic complexity and are transcribed from highly repetitive sequences distributed throughout the genome. Their possible function is considered.
Y1  - 1981
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39765
ER  - 
TY  - JOUR
A1  - Scheer, Ulrich
A1  - Schmidt-Zachmann, Marion S.
A1  - Hügle, Barbara
A1  - Franke, Werner W.
T1  - Identification and localization of a novel nucleolar protein of a high molecular weight by a monoclonal antibody
N2  - A monoclonal murine antibody (No-I 14) is described which reacts specifically with a polypeptide of molecular weight (M,) 180000 present in low-speed nuclear pellets from oocytes and somatic cells of Xenopus laevis and X. borealis and in isolated amplified nucleoli. Two-dimensional gel electrophoresis has revealed the acidic nature of this polypeptide (isoelectric at pH of ca 4.2 in the presence of 9.5 M urea). A relatively large proportion of the protein is extracted at elevated ionic strength( i.e., at 0.4-0.5 M alkali salt) in a form sedimenting at approx. 7-8S , compatible with a monomeric state. It is also extracted by digestion with RNase but not with DNase. In immunofluorescence microscopy, antibody No-114 stains intensely nucleoli of oocytes and all somatic cells examined , including the residual nucleolar structure of Xenopus erythrocytes which are transcriptionally inactive. During mitosis the antigen does not remain associated with the nucleolar organizer regions (NOR) of chromosomes but is released and dispersed over the cytoplasm until telophase when it re-associates with the reforming interphase nucleoli. At higher resolution the immunofluorescent region is often resolved into a number of distinct subnucleolar components of varied size and shape. Immunoelectron microscopy using colloidal gold-coupled secondary antibodies reveals that the M, 180000 protein is confined to the dense fibrillar component of the nucleolus. This conclusion is also supported by its localization in the fibrillar part of segregated nucleoli of cells treated with actinomycin D. We conclude that nucleoli contain a prominent protein of M, 180000 which contributes to the general structure of the dense fibrillar component of the interphase nucleolus , independent of its specific transcriptional activity.
Y1  - 1984
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39786
ER  - 
TY  - JOUR
A1  - Schüssler, Ulrich
T1  - Mobilisation einzelner Elemente in Amphiboliten aus der Umgebung der KTB-Lokation, Zone Erbendorf-Vohenstrauss, nördliche Oberpfalz
N2  - No abstract available
KW  - Mineralogie
Y1  - 1988
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39248
ER  - 
TY  - JOUR
A1  - Thiry, Marc
A1  - Scheer, Ulrich
A1  - Goessens, Guy
T1  - Localization of nucleolar chromatin by immunocytochemistry and in situ hybridization at the electron microscopic level
N2  - Nucleoli are the morphological expression of the activity of a defined set of chromosomal segments bearing rRNA genes. The topological distribution and composition of the intranucleolar chromatin as well as the definition of nucleolar structures in which enzymes of the rDNA transcription machinery reside have been investigated in mammalian cells by various immunogold labelling approaches at the ultrastructural level. The precise intranucleolar location of rRNA genes has been further specified by electron microscopic in situ hybridization with a non-autoradiographic procedure. Our results indicate that the fibrillar centers are the sole nucleolar structures where rDNA, core histones, RNA polymerase I and DNA to po isomerase I are located together. Taking into account the potential value and limitations of immunoelectron microscopic techniques, we propose that transcription of the rRNA genes takes place within the confines of the fibrillar centers, probably close to the boundary regions to the surrounding dense fibrillar component.
Y1  - 1991
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39289
ER  - 
TY  - JOUR
A1  - Gessler, Manfred
A1  - König, A.
A1  - Arden, K.
A1  - Grundy, P.
A1  - Orkin, S. H.
A1  - Sallan, S.
A1  - Peters, C.
A1  - Ruyle, S.
A1  - Mandell, J.
A1  - Li, F.
A1  - Cavenee, W.
A1  - Bruns, G. A.
T1  - Infrequent mutation of the WT1 gene in 77 Wilms' Tumors
N2  - Homozygous deletions in Wilms' tumor DNA have been a key step in the identification and isolation of the WTI gene. Several additional loci are also postulated to contribute to Wilms' tumor formation. To assess the frequency of WTI alterations we have analyzed the WTI locus in a panel of 77 Wilms' tumors. Eight tumors showed evidence for large deletions of several hundred or thousand kilobasepairs of DNA, some of which were also cytogenetically detected. Additional intragenic mutations were detected using more sensitive SSCP analyses to scan all 10 WTI exons. Most of these result in premature stop codons or missense mutations that inactivate the remaining WTI allele. The overall frequency of WTI alterations detected with these methods is less than 15%. While some mutations may not be detectable with the methods employed, our results suggest that direct alterations of the WTI gene are present in only a small fraction of Wilms' tumors. Thus, mutations at other Wilms' tumor loci or disturbance of interactions between these genes likely play an important role in Wilms' tumor development.
KW  - Wilms' tumor
KW  - WTI
KW  - Zinc finger gene
KW  - Tumor suppressor gene
KW  - Nephroblastoma
KW  - Deletion analysis
KW  - SSCP analysis
KW  - Mutation screening
Y1  - 1994
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-34308
ER  - 
TY  - JOUR
A1  - Ellgring, Johann Heinrich
T1  - Psychosoziale Aspekte des Morbus Parkinson
N2  - No abstract available
Y1  - 1992
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-34052
ER  - 
TY  - JOUR
A1  - König, Dorothea
T1  - Materialien zu den Fragmenten des Mihanovic-Homiliars
N2  - No abstract available
Y1  - 1984
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-38566
ER  - 
TY  - JOUR
A1  - König, Dorothea
T1  - Materialien zu den Fragmenten des Mihanovic-Homiliars
N2  - No abstract available
Y1  - 1986
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-38599
ER  - 
TY  - JOUR
A1  - König, Dorothea
T1  - Notizen zum Wortschatz des Vatikanski Hrvatski Molitvenik
N2  - No abstract available
Y1  - 1974
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-38740
ER  - 
TY  - JOUR
A1  - König, Dorothea
A1  - Aitzetmueller, Rudolf
T1  - Die Slavistik an der Universität Würzburg
N2  - No abstract available
Y1  - 1987
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-38778
ER  - 
TY  - JOUR
A1  - Hee, Katrin
T1  - Nicht Tabu
N2  - Dieser Artikel beschreibt eine Unterrichtssequenz für den Deutschunterricht im Bereich Deutsch als Fremdsprache und richtet sich an Lernende der Niveaustufe A2. Er zeigt, wie Lernende spielerisch sowohl rezeptive Sprachkenntnisse als auch aktive Sprachbeherrschung verbessern und ihren Wortschatz erweitern können. Ein besonders wichtiges Kriterium sind dabei der Spielcharakter und die Auflockerung des Unterrichts, sowie die Möglichkeit, individuell auf die Bedürfnisse der Studenten eingehen zu können.
N2  - This paper describes a teaching sequence for German as a foreign language (A2). It shows how learners can improve their receptive and active oral skills, as well as broaden their active and passive vocabulary in a playful way. The main focus is to gain knowledge in the classroom in a relaxed atmosphere, while concentrating on the students´ individual needs.
KW  - Wortschatz
KW  - Spiele im Fremdsprachenunterricht
KW  - Deutsch als Fremdsprache
KW  - Games in language teaching
KW  - German as a foreign language
Y1  - 2009
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39075
ER  - 
TY  - JOUR
A1  - Hee, Katrin
T1  - Ein internationales Kochbuch
N2  - In diesem Artikel wird eine Unterrichtssequenz beschrieben, die sich über einen Zeitraum von zirka 2 Wochen hinzieht und sich an Deutschlernende auf A1-Niveau richtet. Unterrichtsprojekt und Inhalt des Artikels ist ein internationales Kochbuch, das die Studenten selbst entwerfen. Das Projekt eignet sich besonders zur Binnendifferenzierung von großen Gruppen. Jedes Kapitel wird von einer Gruppe bearbeitet, so dass die Studenten je nach Fähigkeiten und Lerntempo individuell ihr Wissen anwenden und erweitern können. Der Artikel gibt einen Überblick über die einzelnen Kapitel des Kochbuches, die jeweiligen Lernziele und allgemeine didaktische Hinweise in Bezug auf das Projekt.
N2  - This paper describes a teaching project which will be aimed at students of German at the A1 level, and observed over a two week period. The project deals with the conception, writing and editing of an international cookbook. The project is particularly suited to the development of individual student´s potential in large groups. Each chapter is edited by a group so that each student can apply and further develop their own individual knowledge and skills, at their own pace. The article gives an overview of each chapter of the cookbook, the respective learning objectives and general educational conventions as to the project.
KW  - Projektarbeit
KW  - Handlungsorientierung
KW  - Deutsch als Fremdsprache
KW  - German as a foreign language
Y1  - 2009
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39067
ER  -