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Prevalence and distribution of bacteriophage phi Aa DNA in strains of Actinobacillus actinomycetemcomitans
R H Stevens1, H R Preus, B Dokko
1Department of Endodontology, School of Dentistry, Temple University, Philadelphia, PA 19104.
Abstract:
phi Aa is a bacteriophage that was originally isolated by induction of a lysogenic strain of the oral bacterium Actinobacillus actinomycetemcomitans. Since the discovery of phage phi Aa, additional phages infecting several other strains of A. actinomycetemcomitans have been identified. To determine the prevalence of phi Aa or phi Aa-related temperate phages in this species, a phi Aa-specific DNA probe was prepared to screen for homologous sequences among 42 strains of A. actinomycetemcomitans. Fourteen (33%) of the 42 strains examined contained DNA sequences that hybridized with the phage phi Aa probe. A bacteriophage designated phi Aa33384 was isolated by induction from one of the strains (ATCC 33384) that contained a sequence that hybridized with the phi Aa probe. The phi Aa probe hybridized with the DNA extracted from bacteriophage phi Aa33384. The distribution of the phage phi Aa sequence among A. actinomycetemcomitans serotypes was 5/13 (38%) of the serotype a strains, 0/16 (0%) of the serotype b strains, and 9/13 (69%) of the serotype c strains. The results of this investigation suggest that the target sequence prepared from the phage phi Aa genome is fairly common in the A. actinomycetemcomitans chromosome, and that the sequence is distributed among the A. actinomycetemcomitans serotypes in a seemingly nonrandom manner.
Insights
Phage phi Aa DNA sequences are common in Actinobacillus actinomycetemcomitans, found in 33% of strains. This sequence distribution varies significantly across different A. actinomycetemcomitans serotypes, suggesting a non-random pattern.
Area of Science:
- Microbiology
- Virology
- Genetics
Background:
- Phage phi Aa was initially isolated from Actinobacillus actinomycetemcomitans, an oral bacterium.
- Subsequent research identified additional phages infecting various A. actinomycetemcomitans strains.
Purpose of the Study:
- To investigate the prevalence of phage phi Aa or related temperate phages within A. actinomycetemcomitans species.
- To analyze the distribution of phage phi Aa sequences across different serotypes of A. actinomycetemcomitans.
Main Methods:
- A specific DNA probe for phage phi Aa was created.
- The probe was used to screen 42 A. actinomycetemcomitans strains for homologous DNA sequences.
- Phage phi Aa33384 was isolated from a positive strain (ATCC 33384).
Main Results:
- Phage phi Aa-related DNA sequences were detected in 14 out of 42 (33%) A. actinomycetemcomitans strains.
- The probe successfully hybridized with DNA from the isolated phage phi Aa33384.
- Sequence distribution varied by serotype: 38% of serotype a, 0% of serotype b, and 69% of serotype c strains harbored the sequence.
Conclusions:
- The phage phi Aa sequence is a relatively common element within the A. actinomycetemcomitans genome.
- The distribution of this sequence among A. actinomycetemcomitans serotypes appears to be non-random.