Search Results - (Author, Cooperation:K. Dehesh)

2014-12-24

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Arabidopsis/*genetics/growth & development/*metabolism ; Arabidopsis Proteins/genetics/metabolism ; Cell Wall/*metabolism ; DNA, Plant/genetics/metabolism ; E2F Transcription Factors/metabolism ; Feedback ; Gene Expression Regulation, Developmental/genetics ; Gene Expression Regulation, Plant/*genetics ; Gene Regulatory Networks/*genetics ; Iron/deficiency ; Organ Specificity ; Promoter Regions, Genetic/genetics ; Reproducibility of Results ; Salinity ; Time Factors ; Transcription Factors/*metabolism ; Xylem/genetics/growth & development/metabolism

0003-9861

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Physics

Electronic Resource

1432-2048

NADPH-protochlorophyl ; lide oxidoreductase ; Barley ; Cellular localization

Springer Online Journal Archives 1860-2000

Biology

Abstract Changes in the relative content of NADPH-protochlorophyllide oxidoreductase during the light-induced greening of barley plants were measured both in the total leaf extract as well as in intact and broken plastids. The enzyme protein was identified by its apparent molecular weight and its immunological crossreactivity with an antiserum directed against the NADPH-protochlorophyllide oxidoreductase. The monospecificity of the antiserum was tested by two different criteria: i. The antiserum was purified by affinity chromatography. ii. It was demonstrated that the antiserum crossreacts with only those polypeptides which appear to be enzymatically active. In the fraction of broken plastids isolated from leaves of briefly illuminated barley plants the concentration of the enzyme protein was reduced drastically. Our results indicate that this decrease in enzyme protein content is the consequence of an artificial proteolytic breakdown of the membrane-bound enzyme protein. In intact plastids and in the total leaf extract the concentration of the enzyme protein did not change dramatically during the first 4 to 6 h of illumination. However, when the exposure to continuous white light was extended further the concentration of the enzyme protein in intact plastids began to decline rapidly while in total leaf extracts the concentration remained almost constant for the next 10 h of light. These results indicate that part of the enzyme protein may be localized outside of the plastid compartment.

Electronic Resource

1432-2048

Enzyme localization ; Hordeum ; Immunogold labelling ; NADPH-protochlorophyllide oxidoreductase

Springer Online Journal Archives 1860-2000

Biology

Abstract The cellular distribution of the 36000-Mr polypeptide of NADPH-protochlorophyllide oxidoreductase has been determined in ultrathin sections of barley leaves by the method of immunogold labelling. In leaves of etiolated seedlings a large portion of the immunoreactive protein was localized within the prolamellar body. However, approximately one third of the total immunoreactive protein was present outside the plastid in the area of the plasmalemma. During illumination of etiolated seedlings the two polypeptide populations were differentially affected by light. While the concentration of the plastid-localized immunoreactive protein rapidly decreased and was hardly detectable after 16 h of continuous white-light treatment, the concentration of the extraplastidic polypeptide did not decline significantly during this illumination period. A similar distribution pattern of the immunoreactive polypeptide was also found in maize and rye. The chlorophyll-deficient barley mutant xantha-l81 contained the immunoreactive 36000-Mr polypeptide, even though the prolamellar body was not detectable in etioplasts of this mutant. All of the immunoreactive polypeptide was localized outside the plastid in the area of the plasmalemma. Despite the apparent absence of the enzyme protein from the plastid, dark-grown mutant plants contained the same relative concentration of mRNA activity for the NADPH-protochlorophyllide oxidoreductase, which declined rapidly during illumination, as in wild-type plants. The antigenic properties and the apparent molecular weight of the plastid-localized NADPH-protochlorophyllide oxidoreductase and the 36000-Mr immunoreactive polypeptide outside the plastid were so similar as to indicate that the two proteins may be of common origin.

Electronic Resource