Use of Heteroduplex Mobility Analysis (HMA) for Differentiating Phytoplasma Isolates Causing Witches' Broom Disease on Populus nigra cv Italica and Stolbur or Big Bud Symptoms on Tomato

Heteroduplex mobility analysis (HMA) was performed to distinguish French and German isolates of phytoplasmas from Populus nigra cv Italica witches broom. The French isolate was similar to the phytoplasma responsible for the European aster yellows while the German isolate was different but closely related to it. When phytoplasmas inducing similar "stolbur" symptoms in tomato were compared to HMA, a high degree of genetic differences was observed among the reference stolbur C (StC) isolate, the European aster yellows and the other phytoplasmas inducing stolbur or big bud symptoms in tomato. Pseudo-stolbur B and D from Brazil were differentiated from the reference St C using this method.     

Isolation and characterisation of five histone H1 subtypes from adult rat liver

A procedure is described for quantitative purification of H10 and five H1-1 subtypes--named H1-1a to e--from adult rat liver by reverse-phase high-pressure liquid chromatography. Milligram amounts of each fraction have been obtained. The H1-1a subtype shows a very high lysine content (34%) and H1-1d subtype has an amino-acid composition close to that of H10, but its electrophoretic mobility is different. Salt dependent folding of these subtypes has been studied by circular dichroism. In the presence of 2 or 10 mM sodium phosphate buffers at pH 7.5, H1-1a shows the lowest alpha-helix content. In phosphate-buffer containing 1 M NaCl the number of residues in alpha-helix for all the subtypes rises to 9-10%. Partial cleavage of these subtypes by endoproteinase Glu-C produce three main peptides arising from C-terminal domains. The interaction of the H1-1 subtypes with 196 basepairs linear DNA, purified from rat liver chromatin by high-pressure ion-exchange liquid chromatography, has for consequences a modification of the patterns of digestion: partial proteolysis of the H1-1a and H1-1b subtypes shows differences in the presence or in absence of DNA; on the contrary, H1-1c and H1-1d seem to have the same organization. So these subtypes may play a role in the differential packing of specific region of chromatin.     

Über die Bedeutung »geringer« Verschiedenheiten der relativen Gröfse der Furchungszellen für den Charakter des Furchungsschemas

Ohne ZusammenfassungTheil I und II dieser Abhandlung wurden bereits als Programm der Universität Halle a. S. besonders abgedruckt. Dies ist der Grund, dass sie erst nach der gleichzeitig mit ihr verfassten Abhandlung Über die Selbstordnung (Cytotaxis) sich berührender Furchungszellen (dies Archiv. Bd. III. Heft 3) hier erscheint, obschon sie ihres zum Theil allgemeinere Verhältnisse der Furchungszellen behandelnden Inhaltes wegen besser vor dieser Platz erhalten hätte.     

C-Glycosylflavonoids. The chemistry of aspalathin

1. The isolation of aspalathin, the principal phenolic constituent in the leaves of Aspalathus linearis, is described and its properties are discussed. 2. The compound has been identified as 3'-C-beta-d-glucopyranosyl-2',3,4,4',6'-pentahydroxydihydrochalcone by the preparation and analysis of various derivatives, by photochemical oxidation to 2,3-dihydroiso-orientin and by nuclear-magnetic-resonance studies.     

A predominant idiotype on rabbit anti-VH a1 allotype antibodies: sharing by both major and minor VH subgroups

In every rabbit examined, greater than or equal to 80% of antibodies directed against the VH allotypic marker, a1, bears a predominant idiotype (IdX-a1). The IdX-a1 marker is site-associated and expressed on H chains, but not L chains, of anti-a1 antibody. Experiments using rabbits suppressed for the VH a subgroup demonstrated that IdX-a1 can be associated with both major (a+) and minor (a-) VH subgroup gene products and that a1 rabbits contain IdX-a1 within their genetic repertoire. The genetic and regulatory implications of our results are discussed.