Publication Date

1979

Document Type

Dissertation/Thesis

First Advisor

Frampton, Elon W.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Biological Sciences

LCSH

Anacystis nidulans; Gyanophyta

Abstract

Anacystis nidulans, strain 625, grown at 39 C in BG-11 medium at a light intensity of 3,000 lux was exposed to a heat stress at 47 C for 30 min in potassium phosphate buffer (0.10 M, pH 7.1) or in BG-11 medium before return to growth conditions. Cell survival was determined on samples plated at intervals on both BG-11 agar and BG-11 agar containing 0.5% (w/v) NaCl as a stressing agent for heat injured cells. Cells heat stressed in phosphate buffer continued to lose viability for 4 hours after being returned to growing conditions as evidenced by the number of survivors on the salt containing agar. After this period, there was a rapid recovery of viability which continued during the next 4 hours. BG-11 heated cells, however, started to recover viability immediately after being returned to growing conditions as evidenced by plating on salt containing agar and recovery was complete after 8 hours. Cell-free extracts from cultures labeled with [³H] uracil and heated (47 C, 30 min.) in phosphate buffer or BG-11 medium were examined for effects on the ribosomal patterns using linear sucrose gradients (5-20% w/v) containing 0.5 mM magnesium. Cells heated in phosphate buffer showed a severe reduction of the 30S ribosome peak and the 30S peak was obliterated by an apparent accumulation of breakdown material. Cells heated in BG-11 medium, however, showed only a slight reduction in the 30S ribosome peak. The 30S ribosomal components of the phosphate buffer heated cells recovered partially after 4 hours of post heating incubation. After 8 hours, both 30S and 50S ribosomal components were observed in cells labeled before heating with [¹⁴C] uracil and after heating with [³H] uracil.

Comments

Includes bibliographical references.||Includes illustrations.

Extent

v, 55 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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