Isolation and characterization of the interspecific fusants from Streptomycetes obtained using a liquid regeneration method

ABSTRACT: Protoplast fusion between different species of Streptomyces was performed using a liquid regeneration method developed for a rapid and simple preparation of the fusants. Consequently, new clones, which could not be obtained using the conventional agar regeneration method, were obtained. In the crosses between S. griseus and S. durhamensis , and between S. californicus and S. catenulae , eight and two recombinants, respectively, were obtained using the liquid regeneration method. Conversely, in the case of crosses between S. ornatus and S. catenulae , and between S. ornatus and S. vendargensis , seven recombinants each were obtained using only the agar method. The physiological characteristics, such as the assimilation of carbohydrate and antibiotic resistance, of these fusants differed considerably from those of their parental strains. Using the proposed liquid regeneration method, a simpler and quicker procedure for protoplast fusion is described.     

Triticeae plants preferentially responded to S-1-α-methylbenzyl-3-p-tolylurea in root growth and tetrazolium reduction assays

Optically active 1-α-methylbenzyl-3- p -tolylurea (MBTU) shows diverse plant physiological properties. Gramineae plants exhibit enantioselective root growth inhibition by R / S -MBTU. In the present paper, the dose–growth response (DGR) towards the optically active MBTUs was examined in the tribe Triticeae plants, including Hordeum vulgare L., Secale cereale L., Triticum aestivum L. and Aegilops cylindrica Host., and compared with those of the genus Bromus ( B. inermis Leyss), which is classified into the tribe Bromeae, and the genus Oryza . In spite of their phylogenetic difference, the Triticeae plants responded homogeneously in their chiral recognition. Of particular interest, is the result of the dichotomic enantioselective response of tested Gramineae plants. Only the genus Oryza responds to R -MBTU, and the tribes Triticeae ( Triticum , Aegilops , Secale and Hordeum ) and Bromeae ( Bromus ) preferentially respond to the S -enantiomer. The tetrazolium–phenazine methosulfate–formazan (TPF) assay was demonstrated to measure redox activity of root tips of the MBTU-treated Oryza sativa and T. aestivum , which are the typical dichotomic, enantioselective-responsive plants. In Oryza and Triticum root tips, enantioselective responses of reduction activity in TPF assays were strongly related to those of root growth inhibition in DGR assays, suggesting aggressive participation of the MBTU in the generation of the reducing mechanism in mitochondria.