Award Date

1-1-1993

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Biological Science

Number of Pages

127

Abstract

Arthrobacters exhibit a dimorphic growth cycle where exponential phase cells appear as irregular bacilli and stationary phase cells as cocci. Arthrobacter globiformis was found to form myceloids when subjected to osmotic stress. Addition of known osmoprotective compounds did not relieve this effect. Since myceloid formation may result from altered penicillin-binding proteins (PBPs), PBP profiles of stressed and unstressed A. globiformis were studied. Eight PBPs were identified, ranging in molecular mass from 91,000 to 30,000 daltons. Myceloids appeared to lack PBP 2a (84 kD) and PBP 2b (82 kD) in all growth conditions. The myceloids were 12-20 times more sensitive to beta-lactam antibiotics than the normal bacteria and 320 times more resistant to streptomycin. Myceloids were more sensitive to heat than the coccal forms and more resistant to long term starvation in a buffer lacking a nitrogen source. These results indicate that myceloid formation in A. globiformis may result from the altered synthesis of specific PBPs.

Keywords

Arthrobacter; Cell; Formation; Globiformis; Myceloid; Osmotic; Stress

Controlled Subject

Microbiology; Molecular biology

File Format

pdf

File Size

4208.64 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

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