Das Corno-Quercetum des Mátra-Gebirges

Zusammenfassung Die zum Aceri-Quercion-Verband gehörenden kontinentalen und kalkholden Corno-Quercetum Wälder sind in dem nordöstlichen Ungarischen Mittelgebirge so im Mátra-Gebirge auf Andesit, auf Kalk- und vulkanischem Grundgestein verbreitet. Einige Bestände der Corno-Quercetum Wälder stehen im Kontakt mit dem auf Lößboden (Tschernosjom-brauner Waldboden) vorhandenen Aceri tatarici-Quercetum des Flachlandes (Randgebiet der Ungarischen Tiefebene).Die artenreichen Bestände sind durch den verhältnismäßig hohen Anteil der Aceri-Quercion Charakterarten und der sog. Waldsteppenarten gut gekennzeichnet.In der floristischen Zusammensetzung des Corno-Quercetum spielen außer den obererwähnten Arten die Elemente von Quercetea pubescenti-petraeae und Querco-Fagetea die Hauptrolle.Auf Grund der Charakterisierung des Standortes der Corno-Quercetum Wälder durch die T-, W- und R-Indikatorwerte der Arten nach Zólyomi (1963, 1964) ist das Corno-Quercetum als eine relativ basischen, mäßig trockenen Standort kennzeichnende, an submediterranen wärmeliebenden Arten reiche Gesellschaft kontinentale Gepräges zu betrachten.Auf Andesit-Grundgestein entstandene Böden (Erubasboden, brauner Waldboden, Parabraunerde) des Corno-Quercetum sind reicher an adsorbiertem Ca, und das ermöglicht das Erscheinen der Bestände und so auch der Arten, die einen gewissen Kalkgehalt und eine neutrale, oder schwach basische Reaktion des Bodens beanspruchen.

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Summary The author describes the Corno-Quercetum oak forests from the Mátra-Mts. in Hungary.Floristic composition indicates requirements for chalk and nitrogen. The author also includes a number of ecological data (temperature, oil-composition, humidity) measured in these forests.

     

A RAPD study of the Sarcostemma group of Cynanchum (Apocynaceae-Asclepiadoideae-Asclepiadeae)

One hundred and thirty-seven accessions of Cynanchum viminale and its relatives, formerly known as Sarcostemma, were studied using randomly amplified polymorphic DNA (RAPD). A fingerprinting technique was used because sequencing had failed to differentiate between morphologically separable groups. Chromosome counts were conducted to establish the ploidy level of the accessions. The banding patterns resulting from RAPD analysis were evaluated with Canonical Analysis of Principal Coordinates, Permanova and neighbour-joining. A strong geographic component was found in the structure of the group. Taxa considered species or subspecies based on morphology often formed coherent groups. The data are interpreted to reflect at least two cycles of diversification: the first one from Madagascar and the second one most likely from the East African–Arabian region, reaching Madagascar again. In mainland Africa, polyploidisation has occurred several times.     

Characterization of an S-layer glycoprotein produced in the course of S-layer variation of<Emphasis Type="Italic"> Bacillus stearothermophilu</Emphasis>s ATCC 12980 and sequencing and cloning of the<Emphasis Type="Italic"> sbsD</Emphasis> gene encoding the protein moiety

The cell surface of Bacillus stearothermophilus ATCC 12980 is completely covered by an oblique lattice which consists of the S-layer protein SbsC. On SDS-polyacrylamide gels, the mature S-layer protein migrates as a single band with an apparent molecular mass of 122 kDa. During cultivation of B. stearothermophilus ATCC 12980 at 67 degrees C instead of 55 degrees C, a variant developed that had a secondary cell wall polymer identical to that of the wild-type strain, but it carried an S-layer glycoprotein that could be separated on SDS-polyacrylamide gels into four bands with apparent molecular masses of 92, 118, 150 and 175 kDa. After deglycosylation, only a single protein band with a molecular mass of 92 kDa remained. The complete nucleotide sequence encoding the protein moiety of this S-layer glycoprotein, termed SbsD, was established by PCR and inverse PCR. The sbsD gene of 2,709 bp is predicted to encode a protein of 96.2 kDa with a 30-amino-acid signal peptide. Within the 807 bp encoding the signal peptide and the N-terminal sequence (amino acids 31-269), different nucleotides for sbsD and sbsC were observed in 46 positions, but 70% of these mutations were silent, thus leading to a level of identity of 95% for the N-terminal parts. The level of identity of the remaining parts of SbsD and SbsC was below 10%, indicating that the lysine-, tyrosine- and arginine-rich N-terminal region in combination with a distinct type of secondary cell wall polymer remained conserved upon S-layer variation. The sbsD sequence encoding the mature S-layer protein cloned into the pET28a vector led to stable expression in Escherichia coli HMS174(DE3). This is the first example demonstrating that S-layer variation leads to the synthesis of an S-layer glycoprotein.