Award Date


Degree Type


Degree Name

Master of Science (MS)


Biological Science

Number of Pages



A group of 95 actinomycete-like bacterial isolates were obtained from the deep subsurface at the Nevada Test Site. These isolates were screened for the ability to inhibit the growth of selected challenge organisms. A subset of 12 isolates were found to produce antibacterial substances during their growth and were termed bioactive. It was hypothesized that because the isolation source was solid rock, some of the bioactive isolates would require the presence of a surface in order to make antibiotic substances, and that some of these isolates would fail to produce antibiotics when grown in broth culture alone. It was further hypothesized that the addition of an exogenous surface to broth cultures of liquid medium-deficient antibiotic producers would restore the lost antibiotic production in some isolates; Nine of the 12 bioactive isolates failed to produce antibiotics when grown in liquid medium and 6 of those 9 liquid medium-deficient isolates could be induced to manufacture antibiotics with the addition of an exogenous surface to the broth cultures; Characterization and profiling studies performed on the bioactive isolates revealed that each was a unique isolate and that they were all capable of cross inhibiting each other to varying degRees The bioactive isolates also appeared to be different from similar non-bioactive isolates obtained from the same sample sites; The deep subsurface at the Nevada Test Site has provided a rich and novel source of bacterial isolates, some of which possess unusual properties. The ability of the bioactive isolates to produce antibiotic substances may be a means by which they increase their evolutionary fitness under conditions of limited nutrient availability, however the true purpose of the observed bioactivity is not known.


Antimicrobial; Characterization; Deep; Microorganisms; Produce; Substance; Subsurface

Controlled Subject


File Format


File Size

2652.16 KB

Degree Grantor

University of Nevada, Las Vegas




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