Kontinental-Verschiebungen : Originalnotizen und Literaturauszüge = Continental Drift : the Original Notes and Quotations

Alfred Wegeners Notizbuch "Kontinental-Verschiebungen" : eine Einführung / von Reinhard Krause und Jörn Thiede: 2005 jährt sich der Geburtstag Alfred-Wegeners zum 125. Mal (geboren 1. November 1880). Bei den Vorbereitungen auf dieses Jubiläum und auf die Feier des 25- jährigen Bestehens der Stiftung Alfred-Wegener-Institut für Polar- und Meeresforschung sind die Unterlagen, die auf Alfred Wegener persönlich zurückgehen, sorgfältig durchgesehen worden. Bei seinem Enkel Dr. Günther Schönharting in Eichhofen / Bayern wurden zwei wichtige Dokumente aufgefunden, nämlich ein umfangreiches Notizbuch mit dem Wort „Kontinental-Verschiebungen“ beschriftet und die erste Auflage seines Buches „Die Entstehung der Kontinente und Ozeane“ (erschienen im Jahr 1915), das mit Leerseiten durchschossen gebunden war, und in dem sich zahlreiche schriftliche Verbesserungen befanden, die in die Gestaltung späterer Auflagen eingingen. Da das Notizbuch „Kontinental-Verschiebungen“ mit seinen zahlreichen Exzerpten und Vermerken ein wertvolles Dokument darstellt, ohne das die wissenschaftliche Auseinandersetzung Alfred Wegeners mit seiner eigenen Hypothese nur schwierig nachzuvollziehen ist, haben wir uns entschieden, dieses Notizbuch zu transkribieren und gemeinsam mit seinem Faksimile in diesem Heft zu veröffentlichen. Möge diese Veröffentlichung eine anregende Quelle für wissenschaftsgeschichtlich interessierte Forscher darstellen

Monitoring of central corneal thickness after phacoemulsification—comparison of statical and rotating Scheimpflug pachymetry, and spectral-domain OCT

AIM: To explore the possibility of deploying three contactless devices (static and rotating Scheimpflug technology, spectral domain optical coherence tomography) for measuring central corneal thickness (CCT) in preoperative and postoperative examinations of cataract patients. METHODS: Totally 72 patients who had undergone surgery without complications were selected. The CCT was measured prior to the operation, as well as on the first, 5th-7th and 28th day following the operation using the Nidek NT 530-P, Sirius®, and Topcon OCT-2000 devices. RESULTS: A significant postoperative increase and subsequent decrease in CCT was identified with all three devices. The correlations were highly significant and thus reflect a very good degree of comparability at all times with the exception of the rotating Scheimpflug camera. The postoperative results from the latter differed significantly from the other devices. The correlations were Sirius/Topcon (P=0.010) and Sirius/Nidek (P<0.0005). No statistically significant difference could be identified in the comparison between Topcon and Nidek (P=0.056). CONCLUSION: All three devices are suitable for postoperative monitoring of CCT. The measurement results are only comparable to a limited extent and not interchangeable in the course of treating a single patient. This is due to the different imaging technology used in the devices and the resulting modalities for conducting the measurements

Exopolysaccharide Characterization of Rhizobium favelukesii LPU83 and Its Role in the Symbiosis With Alfalfa

One of the greatest inputs of available nitrogen into the biosphere occurs through the biological N2-fixation to ammonium as result of the symbiosis between rhizobia and leguminous plants. These interactions allow increased crop yields on nitrogen-poor soils. Exopolysaccharides (EPS) are key components for the establishment of an effective symbiosis between alfalfa and Ensifer meliloti, as bacteria that lack EPS are unable to infect the host plants. Rhizobium favelukesii LPU83 is an acid-tolerant rhizobia strain capable of nodulating alfalfa but inefficient to fix nitrogen. Aiming to identify the molecular determinants that allow R. favelukesii to infect plants, we studied its EPS biosynthesis. LPU83 produces an EPS I identical to the one present in E. meliloti, but the organization of the genes involved in its synthesis is different. The main gene cluster needed for the synthesis of EPS I in E. meliloti, is split into three different sections in R. favelukesii, which probably arose by a recent event of horizontal gene transfer. A R. favelukesii strain devoided of all the genes needed for the synthesis of EPS I is still able to infect and nodulate alfalfa, suggesting that attention should be directed to other molecules involved in the development of the symbiosis.Fil: Castellani, Lucas Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Luchetti, Abril. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Nilsson, Juliet Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Pérez Giménez, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Wegener, Caren. Universitat Bielefeld; AlemaniaFil: Schluter, Andreas. Universitat Bielefeld; AlemaniaFil: Pühler, Alfred. Universitat Bielefeld; AlemaniaFil: Lagares, Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Brom, Susana. Universidad Nacional Autónoma de México; MéxicoFil: Pistorio, Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Niehaus, Karsten. Universitat Bielefeld; AlemaniaFil: Torres Tejerizo, Gonzalo Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; Argentin

Isolation and Characterization of Alfalfa-Nodulating Rhizobia Present in Acidic Soils of Central Argentina and Uruguay

We describe the isolation and characterization of alfalfa-nodulating rhizobia from acid soils of different locations in Central Argentina and Uruguay. A collection of 465 isolates was assembled, and the rhizobia were characterized for acid tolerance. Growth tests revealed the existence of 15 acid-tolerant (AT) isolates which were able to grow at pH 5.0 and formed nodules in alfalfa with a low rate of nitrogen fixation. Analysis of those isolates, including partial sequencing of the genes encoding 16S rRNA and genomic PCR-fingerprinting with MBOREP1 and BOXC1 primers, demonstrated that the new isolates share a genetic background closely related to that of the previously reported Rhizobium sp. Or191 recovered from an acid soil in Oregon (B. D. Eardly, J. P. Young, and R. K. Selander, Appl. Environ. Microbiol. 58:1809–1815, 1992). Growth curves, melanin production, temperature tolerance, and megaplasmid profiles of the AT isolates were all coincident with these characteristics in strain Or191. In addition to the ability of all of these strains to nodulate alfalfa (Medicago sativa) inefficiently, the AT isolates also nodulated the common bean and Leucaena leucocephala, showing an extended host range for nodulation of legumes. In alfalfa, the time course of nodule formation by the AT isolate LPU 83 showed a continued nodulation restricted to the emerging secondary roots, which was probably related to the low rate of nitrogen fixation by the largely ineffective nodules. Results demonstrate the complexity of the rhizobial populations present in the acidic soils represented by a main group of N2-fixing rhizobia and a second group of ineffective and less-predominant isolates related to the AT strain Or191.Instituto de Biotecnologia y Biologia Molecula

Between seas and continents: aspects of the scientific career of Hermann Von Ihering, 1850-1930

This paper covers some periods in Hermann von Ihering’s scientific trajectory: his training in zoology in Germany and Naples, his international activities based in Brazil, and his return to Germany. It deals with aspects of the formulation of his theories on land bridges. It focuses on the network of contacts he maintained with German émigrés like himself, and primarily with Florentino Ameghino, which allowed him to interact in international scientific circles. It mentions excerpts of his letters and his publications in the periods when he began corresponding with Ameghino (1890), when he travelled to Europe in search of support for his theories (1907), and when he published his book on the history of the Atlantic Ocean (1927).Facultad de Ciencias Naturales y Muse