Linked Life Data

2818869

Source:http://linkedlifedata.com/resource/pubmed/id/2818869

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1989-12-27
pubmed:abstractText
Identical samples containing polynucleosomal chains of chicken erythrocyte (CE) and Ehrlich ascites tumour (EA) chromatin were studied under various ionic conditions with regard to electric linear dichroism (ELD) and flow linear dichroism (FLD). Both orientation techniques consistently confirmed that, in the limit of very low ionic strength and in the absence of multivalent cations, the reduced linear dichroism of chromatin is negative in the DNA-base absorption band, as expected for an extended zig-zag polynucleosomal conformation. With increasing electrolyte content, both ELD and FLD decreased drastically in amplitude, but in contrast to the ELD which remains negative in an intermediate range of low ionic strength (0.1-0.5 mM Mg2+) the FLD changes sign and becomes positive. The ELD and FLD amplitudes decrease with higher Mg2+ concentrations and FLD even vanishes in the region of 0.2-0.4 mM; both signals are positive above 0.4-0.5 mM Mg2+. The origin of the dissimilarities between ELD and FLD observations is still not fully understood. Several possibilities are considered: ELD signals are more influenced than FLD by the presence of short chromatin chains, nucleosomes and small pieces of naked DNA, while FLD is more susceptible to the presence of large, easily orientable, scattering aggregates. Different preferred orientation directions of the chromatin fibre with respect to electric and hydrodynamic fields may also be involved. Finally, FLD and ELD probably "see" different features of the chromatin structure.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0739-1102
pubmed:author
pubmed:issnType
Print
pubmed:volume
7
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
19-33
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Electric and flow linear dichroism of unfolded and condensed chromatin: a comparative study at low and intermediate ionic strength.
pubmed:affiliation
Department of Physical Chemistry, Chalmers University of Technology, Gothenburg, Sweden.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't