Isolation and characterization of plasmids from Streptomyces.
نویسندگان
چکیده
In view of the importance of actinomycetes in the production of antibiotics, it would be useful to find plasmids in these organisms in order to construct molecular breeding systems. Since the first discovery of plasmid involvement in antibiotic production", several plasmids associated with the production of antibiotics have been found in Streptomyces (references are listed in AKAGAWA et al.-'). For the study of gene cloning, plasmids with smaller molecular weights are preferable for use as cloning vehicle. In order to find candidates for vector plasmids and to extend the study of plasmid involvement in antibiotic production, we examined thirty-four strains of actinomycetes for plasmids (Table 1). Among them, we found a linear plasmid-like DNA from a lankacidin producer, Streptomyces sp. 7434-AN,3'. In this communication, we report the isolation and characterization of covalently closed circular (CCC) DNA molecules from four strains among the strains we tested. Cells of Streptomyces puniceus KCC-S-0406, Streptomyces sp. 2217-G,, Streptotni'ces sp. 7068-CC, and Streptomyces hygroscopicus 434 were grown at 27°C in a medium which contained (in grams per liter): glucose, 3; peptone, 3; yeast extract, 4; pH 7.0. The methods for isolation of CCC DNA and the preparation of ['H]thymidine-labeled DNA were as described previously for the isolation of plasmids from Bacillus subtilis4). ['H]Labeled CCC DNAs obtained from CsCI-ethidium bromide (EtBr) density gradients were subjected to neutral 5 to 20% (w/v) linear sucrose gradient centrifugation with [14C]Iabeled l DNA added as an internal standard (33.6S) for determination of molecular weights.
منابع مشابه
Characterization of replication and conjugation of Streptomyces circular plasmids pFP1 and pFP11 and their ability to propagate in linear mode with artificially attached telomeres.
Many Streptomyces species harbor circular plasmids (8 to 31 kb) as well as linear plasmids (12 to 1,700 kb). We report the characterization of two newly detected circular plasmids, pFP11 (35,139 bp) and pFP1 (39,360 bp). As on linear plasmids, their replication loci comprise repA genes and adjacent iterons, to which RepA proteins bind specifically in vitro. Plasmids containing the minimal itero...
متن کاملCharacterization of proteolytic enzyme secreted by Streptomyces cinereoruber ssp. cinereoruber isolated from human pleural fluid
Actinomycetes are an uncommon agent of human infections and its pathogenic factors are not known. The present study reports a rare case isolation of an actinomycete from a woman pleural fluid; the strain was identified by 16S rRNA gene sequence analysis. This strain was tested to produce an extracellular protease that hydrolysis gelatin, casein and hemoglobin on agar mediums. The purification o...
متن کاملCharacterization of proteolytic enzyme secreted by Streptomyces cinereoruber ssp. cinereoruber isolated from human pleural fluid
Actinomycetes are an uncommon agent of human infections and its pathogenic factors are not known. The present study reports a rare case isolation of an actinomycete from a woman pleural fluid; the strain was identified by 16S rRNA gene sequence analysis. This strain was tested to produce an extracellular protease that hydrolysis gelatin, casein and hemoglobin on agar mediums. The purification o...
متن کاملIsolation and evaluation of cytotoxic and antioxidant activity of bioactive metabolites of cultured actinobacteria in Persian Gulf marine sediments
Screening bacteria for bioactive compounds is the first step in the drug discovery programs. The aim of the present research was to achieve cytotoxic and antioxidant metabolites from actinobacteria of Persian Gulf sediments and to investigate the effects of combinations of seven treatments and six isolation media on the selective isolation process. A total of 395 actinobacterial isolates were c...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- The Journal of antibiotics
دوره 32 12 شماره
صفحات -
تاریخ انتشار 1979