PubMed · 6101042
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
1981. Restriction endonucleases.. https://pubmed.ncbi.nlm.nih.gov/6101042/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
SETTING: University-affiliated Mycobacteriology Reference Laboratory. OBJECTIVE: To determine the genetic differences of 25 BCG isolates representing 16 referenced substrains. DESIGN: Non-randomized, observational study based on the visual comparison of the large restriction fragment (LRF) patterns created by digesting each BCG isolate's DNA with an infrequent cutting restriction endonuclease (DraI, AsnI, XbaI or SpeI) and separating the resultant DNA fragments with pulsed field gel electrophoresis. RESULTS: The 25 BCG isolates gave 13 different DraI LRF patterns, 11 different XbaI LRF patterns, 11 different AsnI LRF patterns, and 15 different SpeI LRF patterns. Examples of the same BCG substrains from different sources produced the same LRF patterns for only 2 of 6 substrains studied. These findings suggest a significant degree of genetic diversity in this group of isolates despite a common origin. Four clinical BCG isolates gave LRF patterns identical to BCG Tice, BCG Connaught or BCG Glaxo. The BCG LRF patterns more closely resembled patterns of Mycobacterium bovis than M. tuberculosis. CONCLUSIONS: LRF patterns can accurately identify specific BCG substrains and will be useful in epidemiologic studies, monitoring vaccine production and studies of BCG vaccine efficacy.
Desiccation by vacuum-drying inactivates the restriction endonuclease HindIII completely. However, when dried in the presence of a disaccharide such as trehalose, maltose, or sucrose, the endonuclease retains its lambda DNA-cleaving activity and produces the same digestive fragments as does the intact enzyme. Thus, the disaccharides are effective in protecting the restriction enzyme in terms of both recognition and accurate cleavage of the substrate. Among the disaccharides, trehalose protects the enzyme most effectively; and it also stabilizes the enzyme during dilution in aqueous solution. The restriction enzyme dried with trehalose maintains its activity without detectable loss for at least 4 days at 37 degrees C, but it shows reduced activity after 30-day storage at either 4 degrees C or room temperature. Trehalose also protects other restriction endonucleases, EcoRI and BamHI, from inactivation during vacuum-drying, whereas drying them alone leads to severe loss of their activity. The restriction endonucleases dried with trehalose retain their activities for at least 20 days at 4 degrees C and for 7 days at room temperature.
Genomic variations of herpes simplex viruses type 2 (HSV 2) isolated from Chiang Mai, Thailand and Okinawa, southernmost part of Japan were studied. The genomic polymorphism of 40 HSV 2 Chiang Mai strains and 10 HSV 2 Okinawan strains was analyzed by means of the variations of cleavage sites and electrophoretic mobilities of DNA fragments after digestion with 4 restriction endonucleases (RE (BamH I, Kpn I, EcoR I, and Bgl II)). Using the main 6 variable RE cleavage sites, HSV 2 strains were classified into 10 major groups. The strains categorized into group 1 and 9 were predominant in Chiang Mai. Groups 1, 3, 4, 5, 6 and 7 were found only in Chiang Mai, but contained only a few strains each. Groups 2 and 10 were found only in Okinawa, whereas groups 8 and 9 were found in both Chiang Mai and Okinawa.