Buoyant densities of DNA from various strains of Streptococcus mutans.

نویسندگان

  • G M Dunny
  • T Hausner
  • D B Clewell
چکیده

CARIOGENESIS has been correlated with the presence of certain streptococci in the oral cavity and on tooth surfaces. Various studies dealing with the serological relationships of cariogenic strains resembling Streptococcus mutans (CLARKE, 1924; EDWARDSSON, 1968) have implied a certain amount of heterogeneity within this group (Tow and SHKLAIR, 1967; ZINNER and JABLON, 1968; BRATTHALL, 1970). Recent studies by COYKENDALL (1970; 1971), involving melting point determinations and homology studies on deoxyribonucleic acid extracted from different strains, indicate that these microorganisms vary widely in their genetic material and should probably be classified into several groups. In this communication, we present data dealing with CsCl buoyant density determinations on DNA isolated from various strains of Strept. mutans and essentially confirm, using a different method of analysis, the results of COYKENDALL. The strains used in this study were obtained from Dr. COYKENDALL and have been described previously (COYKENDALL, 1970). Stock cultures were maintained in ToddHewitt Broth (Difco) with CaCO, added. They were periodically recultured and checked for purity. Growth, lysis and extraction was as follows: 2 ml of the stock culture was inoculated into 30 ml of Todd-Hewitt Broth and incubated at 37°C overnight, This entire culture was then added to 500 ml of Todd-Hewitt Broth plus (if the DNA was to be isotopically labelled) 0 5 mCi of thymidine-methyl-[ 3H] [6.7 Ci/mM (New England Nuclear)] and incubated at 37°C with occasional swirling. Growth was measured turbidimetrically until it approached late log phase (5-7 hr). The cells were then placed in an ice bath to stop growth, harvested and washed with 100 ml of distilled water. They were resuspended in 7.5 ml of 25 per cent sucrose to which 1.25 ml of 0.25 M EDTA (pH 8 -0) was added. Then 2.5 ml of a 5 mg/ml solution of lysozyme (Calbiochem) in H,O was added and the mixture (at pH 8.0) incubated 2-2.5 hrs at 37°C. To this 2.5 ml of a 5 mg/ml pronase (Calbiochem) solution was added and the mixture incubated another 30 min. Cells were lysed by adding 5 ml of a 2 per cent

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Genetic transformation of Streptococcus mutans.

Three strains of Streptococcus mutans belonging to serotypes a, c, and f were transformed to streptomycin resistance by deoxyribonucleic acids derived from homologous and heterologous streptomycin-resistant strains of S. mutans and Streptococcus sanguis strain Challis. Homologous transformation of S. mutans was less efficient than heterologous transformation by deoxyribonucleic acids from other...

متن کامل

Investigating the antibacterial effects of some Lactobacillus, Bifidobacterium and acetobacter strains killed by different methods on Streptococcus mutans and Escherichia coli

Although there are many health advantages assigned to different live bacteria such as probiotics, some health threatening effects have also been reported. For example, live bacteria can transfer antibiotic resistance genes to other commensal and opportunistic bacteria of gastrointestinal tract. Recently, it was shown that using killed bacteria have some advantages over live ones. In this resear...

متن کامل

The Effect of Silver Nano Particles on Candida Albicans and Streptococcus Mutans in Denture Acrylic Resins

Introduction: Denture stomatitis is a common complication in patients wearing dentures and preventing the proliferation of related microorganisms and their induced infections is noteworthy. The aim of the present study was to assess the antimicrobial effect of acrylic resins containing various concentrations of silver nanoparticles, on Candida albicans and Streptococcus mutans. Materials and Me...

متن کامل

Identification of unique bacterial gene segments from Streptococcus mutans with potential relevance to dental caries by subtraction DNA hybridization.

Using DNA subtractive hybridization, 49 unique gene segments were identified from a strain of Streptococcus mutans that was isolated from a patient with severe early childhood caries (S-ECC). Further hybridization with DNA from other S. mutans strains isolated from both caries-active and caries-free subjects yielded five unique sequences of DNA common to strains associated with S-ECC.

متن کامل

ذخیره 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 نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Archives of oral biology

دوره 17 6  شماره 

صفحات  -

تاریخ انتشار 1972