Abstract: The invention relates to novel polycyclic alkaloids of formula ##STR1## in which R.sup.1 represents hydrogen or hydroxy, R.sup.2 represents hydrogen or acyl and A and B, independently of one another, each represents C.dbd.O or C--OH, and wherein the dashed line represents a C.dbd.C double bond at the position of the middle bond when A or B represents C.dbd.O, or at the position of the two outer bonds when A or B represents C--OH, a process for the manufacture of these compounds by fermentation of a novel microorganism of the species Myxococcus xanthus, the novel microorganism itself, pharmacetical preparations that contain the novel compounds, and the use of the novel compounds as antibiotics and as tumour-inhibiting agents and for the manufacture of pharmaceutical preparations.

Abstract: The invention describes a process for culturing proliferating aggregates of plant cells, which comprises (a) uniformly plating isolated protoplasts, or isolated cells regenerated from protoplasts, in or on an agarose-solidified culture medium, and/or (b) cutting this pretreated and solidified culture medium into segments, transferring said segments to a liquid nutrient solution and continuing culturing in both cases until the cell aggregates have attained the desired size.

Abstract: Maize cDNA coding for nitrite reductase is cloned, using a spinach nitrite reductase cDNA as a heterologous probe, and is characterized. A method is provided to use the cloned maize nitrite reductase cDNA to determine the number of nitrite reductase genes per maize genome and to study nitrite reductase mRNA regulation in maize.