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.     

Molecular Evolutionary Analyses of Nuclear-Encoded Small Subunit Ribosomal RNA Identify an Independent Rhizopod Lineage Containing the Euglyphina and the Chlorarachniophyta

The Rhizopoda comprise a diverse assemblage of protists which depend on lobose or filose pseudopodia for locomotion. The biochemical and morphological diversity of rhizopods has led to an uncertain taxonomy. Ribosomal RNA sequence comparisons offer a measure of evolutionary relatedness that is independent of morphology and has been used to demonstrate a polyphyletic origin of the Lobosea. We sequenced complete small subunit ribosomal RNA coding regions from the filose amoebae, Euglypha rotunda and Paulinella chromatophora (Euglyphina) to position these taxa in the eukaryote phylogeny. The neighbor-joining analyses show that E. rotunda and P. chromatophora share a monophyletic origin and are not closely related to any lobose amoebae in our analyses. Instead, the Euglyphina form a robust sister group to the Chlorarachniophyta. These results provide further evidence for the polyphyly of the Rhizopoda and support the creation of a new amoeboid lineage which includes the Euglyphina and the chlorarachniophyte algae; taxa with tubular mitochondrial cristae and filose or reticulate pseudopodia.