Disc Electrophoretic Studies of IAA Oxidases and their Relationship with Rooting of Etiolated Stem. Segments of Populus nigra

Stem segments of Populus nigra did not root in water but rooted in glucose + IAA. Rooting was completely inhibited by cyclobeximide or actinomycin-D, added to the medium. The synthesis of two existing and one new isoenzyme was repressed at 24 h in segments cultured in glucose + IAA, but that of two new ones was induced in water. Cycloheximide and actinomycin-D induced the synthesis of some new isoenzymes although they inhibited the fresh turn-over of some others.     

Review of Eumyzus Shinji (Homoptera: Aphididae) with descriptions of two new species from the Indian region

Abstract. The genus Eumyzus Shinji is reviewed. Two new species, E.hydrangi sp.n. infesting Hydrangea scandens and E.pruni sp.n. infesting Prunus cornuta , are described from the Garhwal range of northwest Himalaya. A key to the apterous viviparous females of Eumyzus spp. is given.     

Circular DNA of Entamoeba histolytica Encodes Ribosomal RNA

. The presence of repeated DNA sequences encoding RNA in Entamoeba histolytica has been reported. In the present study we demonstrate by agarose gel electrophoresis, DNase digestion and electron microscopic analysis that these genes are located on extrachromosomal circular DNA molecules with an approximate size of 26 kb. Detection of replication intermediates suggests the episomal nature of these molecules.
Amplified, extrachromosomal rRNA genes appear to be a common feature among the lower eukaryotes, occurring more commonly as linear molecules and less commonly as circles. Entamoeba histolytica is 1 of the few organisms studied in which rRNA genes are located predominantly on extrachromosomal circles.