Seven thermophilic Bacillus phages were characterized with reference to their host range, time of appearance, morphology of plaques, thermal inactivation, stability, lipid presence and inactivation by ultraviolet irradiation. Response surface methodology was adapted to describe the response of growth parameters to environmental changes. Most phages were susceptible to temperatures above 60^oC and inactivated immediately at 103^oC. Most phages were resistant to pH ranges 5 to 9 and almost all to pH 7 to 8. Both phages 46 and 80 were highly resistance to UV exposure for 13 minutes and 20 minutes, respectively. The presence of chloroform or 75% ethanol showed no effect on almost all isolated phages that indicate of possibility of the absence of lipids. The isolated phages were slow in their growth, possibly due to the lower gross growth efficiency.

Genetic polymorphism by RAPD-PCR and phenotypic characteristics of isolated thermotolerant Bacillus strains from hot springs sources

Hazem A. and Manar A.

Microbiologica 26: 249-256 (2003).

The polymerase chain reaction (PCR) based random amplified DNA (RAPD) assay, morphological, physiological, biochemical and antimicrobial susceptibility test methods have been evaluated for use in the taxonomy of isolated thermotolerant Bacillus from Jordanian hot springs, with specific reference to strain Geobacillus stearothermophilus (ATCC 12980), Bacillus circulans (ATCC 4513) and Bacillus sphaericus (ATCC 14577). A RAPD assay has been optimized and is able to discriminate between numerous thermotolerant Bacillus strains. RAPD-PCR was found to give reproducible thermotolerant Bacillus strains classification of DNA fingerprints for 14 strains including 3 reference strains. A study of 14 isolates and 3 reference strains, analyzing 53 phenotypic characters, resulted in their allocation to five major clusters at 60% similarity. Whereas at 80% similarity, twelve taxonomically distinct groups were evident.  

  * Faculty: Allied Health Sciences/ Medical Laboratory Sciences.