Linked Life Data

9613585

Source:http://linkedlifedata.com/resource/pubmed/id/9613585

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
1998-6-18
pubmed:abstractText
Plastids contain a NAD(P)H-plastoquinone-oxidoreductase (NDH complex) which is homologous to the eubacterial and mitochondrial NADH-ubiquinone-oxidoreductase (complex I), but the metabolic function of the enzyme is unknown. The enzyme consists of at least eleven subunits (A-K), which are all encoded on the plastid chromosome. We have mutagenized ndhC and ndhJ by insertion, and ndhK and ndhA-I by deletion and insertion, of a cassette which carried a spectinomycin resistance gene as a marker. The transformation was carried out by the polyethylene glycol-mediated plastid transformation method. Southern analysis revealed that even after repeated regeneration cycles each of the four different types of transformants had retained 1-5% of wild-type gene copies. This suggests that complete deletion of ndh genes is not compatible with viability. The transformants displayed two characteristic phenotypes: (i) they lack the rapid rise in chlorophyll fluorescence in the dark after illumination with actinic light for 5 min; in the wild-type this dark-rise reflects a transient reduction of the plastoquinone pool by reduction equivalents generated in the stroma; and (ii) transformants with defects in the ndhC-K-J operon accumulate starch, indicating inefficient oxidation of glucose via glycolysis and the oxidative pentose phosphate pathway. Both observations support the theory of chlororespiration, which postulates that the NDH complex acts as a valve to remove excess reduction equivalents in the chloroplast.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0026-8925
pubmed:author
pubmed:issnType
Print
pubmed:volume
258
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
166-73
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Mutagenesis of the genes encoding subunits A, C, H, I, J and K of the plastid NAD(P)H-plastoquinone-oxidoreductase in tobacco by polyethylene glycol-mediated plastome transformation.
pubmed:affiliation
Botanisches Institut der Ludwig-Maximilians-Universität, München, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't