scholarly journals A PHASE CONTRAST STUDY OF THE CHROMATINIC BODIES OF ESCHERICHIA COLI SUBSEQUENT TO ULTRAVIOLET IRRADIATION

1956 ◽  
Vol 71 (4) ◽  
pp. 462-473 ◽  
Author(s):  
J. R. Cortelyou ◽  
L. M. Amundson ◽  
M. A. McWhinnie
Keyword(s):  
Escherichia Coli ◽  
Ultraviolet Irradiation ◽  
Phase Contrast ◽  
Contrast Study

Different Reparability of the Chromosomal and Cytoplasmic Deoxyribonucleic Acid in Escherichia coli Damaged by γ and Ultraviolet Irradiation

1978 ◽  
Vol 76 (3) ◽  
pp. 587 ◽  
Author(s):  
Drago Petranović ◽  
Mirjana Petranović ◽  
Ranka Nožinić ◽  
Željko Trgovčević ◽  
Drago Petranovic ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Ultraviolet Irradiation ◽  
Deoxyribonucleic Acid

scholarly journals Release of Compact Nucleoids with Characteristic Shapes from Escherichia coli

2001 ◽  
Vol 183 (17) ◽  
pp. 5041-5049 ◽  
Author(s):  
Steven B. Zimmerman ◽  
Lizabeth D. Murphy
Keyword(s):  
Escherichia Coli ◽  
Genomic Dna ◽  
Phase Contrast ◽  
Cell Envelope ◽  
Simple Procedure ◽  
Sodium Dodecyl ◽  
Cell Lysis ◽  
Exponential Phase ◽  
Stable Form ◽  
General Shape

ABSTRACT The genomic DNA of bacteria is contained in one or a few compact bodies known as nucleoids. We describe a simple procedure that retains the general shape and compaction of nucleoids from Escherichia coli upon cell lysis and nucleoid release from the cell envelope. The procedure is a modification of that used for the preparation of spermidine nucleoids (nucleoids released in the presence of spermidine) (T. Kornberg, A. Lockwood, and A. Worcel, Proc. Natl. Acad. Sci. USA 71:3189–3193, 1974). Polylysine is added to prevent the normal decompaction of nucleoids which occurs upon cell lysis. Nucleoids retained their characteristic shapes in lysates of exponential-phase cells or in lysates of cells treated with chloramphenicol or nalidixate to alter nucleoid morphology. The notably unstable nucleoids of rifampin-treated cells were obtained in compact, stable form in such lysates. Nucleoids released in the presence of polylysine were easily processed and provided well-defined DNA fluorescence and phase-contrast images. Uniform populations of nucleoids retaining characteristic shapes could be isolated after formaldehyde fixation and heating with sodium dodecyl sulfate.

Relative Roles of uvrA and recA Genes in the Recovery of Escherichia coli and Phage λ after Ultraviolet Irradiation

1980 ◽  
Vol 83 (2) ◽  
pp. 323
Author(s):  
Erika Salaj-Šmic ◽  
Drago Petranović ◽  
Mirjana Petranović ◽  
Željko Trgovčević ◽  
Erika Salaj-Smic ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Ultraviolet Irradiation

scholarly journals CONTRACTION IN GLYCERINATED MYOFIBRILS OF AN INSECT (ORTHOPTERA, ACRIDIDAE)

1964 ◽  
Vol 21 (3) ◽  
pp. 385-396 ◽  
Author(s):  
D. Gilmour ◽  
P. M. Robinson
Keyword(s):  
Ionic Strength ◽  
Salt Solution ◽  
Phase Contrast ◽  
High Ionic Strength ◽  
Contrast Study ◽  
Thick Filaments ◽  
Band Region

The A substance of glycerol-treated myofibrils of the femoral muscles of the locust Gastrimargus musicus (Fabr.), removed by a salt solution of high ionic strength, has the properties of actomyosin. A phase contrast study of these fibrils, contracted by the addition of ATP, has revealed that the A bands of most myofibrils shorten during contraction. Changes in density within the A band lead to the formation of Cm and Cz bands while I bands are still present. The A band region between the contraction bands is of much lower density than it is in the uncontracted fibril. During contraction in some fibrils the I bands disappeared and the A bands remained unchanged in length until contraction bands appeared. These results have been interpreted in terms of coiling and stretching of the thick filaments of the sarcomere.

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