We analyzed global gene expression in Arabidopsis in response to various hormones and in related experiments as part of the AtGenExpress project. The experimental agents included seven basic phytohormones (auxin, cytokinin, gibberellin, brassinosteroid, abscisic acid, jasmonate and ethylene) and their inhibitors. In addition, gene expression was investigated in hormone-related mutants and during seed germination and sulfate starvation. Hormone-inducible genes were identified from the hormone response data. The effects of each hormone and the relevance of the gene lists were verified by comparing expression profiles for the hormone treatments and related experiments using Pearson's correlation coefficient. This approach was also used to analyze the relationships among expression profiles for hormone responses and those included in the AtGenExpress stress-response data set. The expected correlations were observed, indicating that this approach is useful to monitor the hormonal status in the stress-related samples. Global interactions among hormones-inducible genes were analyzed in a pairwise fashion, and several known and novel hormone interactions were detected. Genome-wide transcriptional gene-to-gene correlations, analyzed by hierarchical cluster analysis (HCA), indicated that our data set is useful for identification of clusters of co-expressed genes, and to predict the functions of unknown genes, even if a gene's function is not directly related to the experiments included in AtGenExpress. Our data are available online from AtGenExpressJapan; the results of genome-wide HCA are available from PRIMe. The data set presented here will be a versatile resource for future hormone studies, and constitutes a reference for genome-wide gene expression in Arabidopsis.
Correlating continental red-bed successions in the sub-surface is a common problem for the hydrocarbon industry. These successions are typically barren of fauna and often monotonous, leading to non-diagnostic wire-line log signatures. A high-resolution, high precision study of detrital garnet chemistry within Triassic reservoir sandstones from the Beryl Field of the North Sea failed to subdivide the sequence satisfactorily. However, the whole-rock concentrations of immobile trace elements such as Zr, Nb and Cr can be shown to be controlled primarily by the abundances of the heavy minerals zircon, rutile and chrome-spinel, respectively. The chemistry of detrital rutile and chrome spinel varies widely within any one sample, implying that the whole-rock concentrations of Nb and Cr are also a function of the chemistry of these heavy minerals. Having calibrated a type well with a detailed mineralogical and geochemical study, it was possible to correlate between wells using whole-rock geochemical cross-plots.
Synopsis
Minor occurrences of nepheline syenite are present in a hypabyssal intrusion composed predominantly of alkali olivine dolerite, at Cnoc Rhaonastil, Islay. Their mineralogy is dominated by albite and kaersutite, but minor, strongly zoned sodic pyroxenes of the hedenbergite-aegirine solid solution series are present. These pyroxenes contain up to 5.30 wt% ZrO
2
. Two Zr-rich end-member substitutions are important: (1) NAZAL (NaZrAlSiO
6
) and (2) FM-NAZ (Na(Fe,Mg)
0.5
Zr
0.5
Si
2
O
6
), although the latter is probably dominant. There is no clear overall interdependence between zirconium content and pyroxene end-member compositions, implying crystallization was from localized Zr-rich domains in a residual felsic liquid. The earlier crystallization of pure calcic catapleiite (CaZrSi
3
O
9
.2H
2
O) may have caused localized depletions in the Zr content of the melt. As far as we are aware, this is the first reported occurrence of zirconian aegirine from Scotland, and only the second reported occurrence of stoichiometric Ca-catapleiite in the literature.
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