Molecular evolution of nuclear genes in Cupressacea, a group of conifer trees. (1/31)

We surveyed the molecular evolutionary characteristics of 11 nuclear genes from 10 conifer trees belonging to the Taxodioideae, the Cupressoideae, and the Sequoioideae. Comparisons of substitution rates among the lineages indicated that the synonymous substitution rates of the Cupressoideae lineage were higher than those of the Taxodioideae. This result parallels the pattern previously found in plastid genes. Likelihood-ratio tests showed that the nonsynonymous-synonymous rate ratio did not change significantly among lineages. In addition, after adjustments for lineage effects, the dispersion indices of synonymous and nonsynonymous substitutions were considerably reduced, and the latter was close to 1. These results indicated that the acceleration of evolutionary rates in the Cupressoideae lineage occurred in both the nuclear and plastid genomes, and that generally, this lineage effect affected synonymous and nonsynonymous substitutions similarly. We also investigated the relationship of synonymous substitution rates with the nonsynonymous substitution rate, base composition, and codon bias in each lineage. Synonymous substitution rates were positively correlated with nonsynonymous substitution rates and GC content at third codon positions, but synonymous substitution rates were not correlated with codon bias. Finally, we tested the possibility of positive selection at the protein level, using maximum likelihood models, assuming heterogeneous nonsynonymous-synonymous rate ratios among codon (amino acid) sites. Although we did not detect strong evidence of positively selected codon sites, the analysis suggested that significant variation in nonsynonymous-synonymous rate ratio exists among the sites. The most likely sites for action of positive selection were found in the ferredoxin gene, which is an important component of the apparatus for photosynthesis.  (+info)

Labdane-type diterpenoids from the wood of Cunninghamia konishii. (2/31)

Five new labdane-type diterpenes, 12beta,19-dihydroxymanoyl oxide (1), 8(17),13-labdadien-12,15-olid-19-oic acid (2), 12,15-epoxy-8(17),13-labdadien-18-oic acid (3), 8alpha-hydroxy-11E,13Z-labdadien-15-al (4), and (13R)-13-hydroxy-8(17), 11E,14-labdatrien-18-oic acid (5) were isolated from the wood of Cunninghamia konishii. Their structures were elucidated by two-dimensional NMR spectroscopy.  (+info)

Four new podocarpane-type trinorditerpenes from the bark of Taiwania cryptomerioides. (3/31)

Further studies on the bark of Taiwania cryptomerioides found four new podocarpane derivatives, 1beta,13-dihydroxy-8,11,13-podocarpatriene (1), 14,18-dihydroxy-13-methoxy-8,11,13-podocarpatriene (2), 1beta,14-dihydroxy-13-methoxy-8,11,13-podocarpatriene-2,7-dione (3), and 3beta,14-dihydroxy-13-methoxy-8,11,13-podocarpatrien-7-one (4), together with a known 1beta,13,14-trihydroxy-8,11,13-podocarpatrien-7-one (5). Those structures were elucidated principally from spectral evidence.  (+info)

Cloning and expression of an ABSCISIC ACID-INSENSITIVE 3 (ABI3) gene homologue of yellow-cedar (Chamaecyparis nootkatensis). (4/31)

A homologue of the ABI3 gene was isolated from the conifer species, Chamaecyparis nootkatensis. The deduced protein of 794 amino acids exhibited sequence similarity to other VP1/ABI3 proteins within four regions. Expression occurs exclusively in seeds, with no detectable mRNA in leaves and roots. Unlike the homologues of angiosperms, CnABI3 may be encoded by more than one gene.  (+info)

Cadinane-type sesquiterpenes from the roots of Taiwania cryptomerioides Hayata. (5/31)

Five new cadinane-type sesquiterpenes, 15-acetoxy-T-muurolol (1), isokhusinodiol (2), cadin-10(14)-ene-4beta,5alpha-diol (3), cadinane-4beta,5alpha,10beta-triol (4), and muurolane-4beta,5beta,10beta-triol (5), together with five known compounds, T-cadinol (6), T-muurolol (7), alpha-cadinol (8), delta-cadinol (9), and khusinodiol (10), were isolated from the roots of Taiwania cryptomerioides. The structure of the new constituents were elucidated through chemical and spectral studies.  (+info)

Three novel 5(6-->7)abeoabietane-type diterpenes from the bark of Taiwania cryptomerioides. (6/31)

Three new 5(6-->7)abeoabietane diterpenes with the uncommon skeleton of fused 6-5-6 rings were isolated from the bark of Taiwania cryptomerioides designated as taiwaniaquinone F (8), taiwaniaquinol C (9) and taiwaniaquinol D (10). Meanwhile, two known compounds, taiwaniaquinones A (1) and D (4), were also obtained. Their structures were determined principally from spectral evidence.  (+info)

Two new compounds from the leaves of Calocedrus microlepic var. formosana. (7/31)

Two new compounds, 15-methoxypinusolidic acid (1) and isonerylgeraniol-18-oic acid (2) together with four knowns taiwaniaflavone (3), nerylgeraniol-18-oic acid (4), 3-(3,4-dihydroxyphenyl)-1-propanol (5), and amentoflavone (6) are isolated from the leaves of Calocedrus microlepic var. formosana. Compounds 1 and 2 were elucidated as labdane diterpene and linear diterpene, respectively, through spectral studies.  (+info)

The occurrence of polyprenols in seeds and leaves of woody plants. (8/31)

The contents of the heterogenous group of polyisoprenoids was found about two orders of magnitude lower in seeds than the amount of polyprenols and/or their carboxylic esters accumulated during vegetation season in leaves. In contrast to leaves, no seeds were found containing more than 0.5 mg of these lipids per gram of dry tissue. Almost 50% had less than 0.01 mg/g - the amount which is the limit of detection by the procedure used in this work. In gymnosperms (10 representatives of Cupressaceae, Pinaceae and Taxaceae) the polyprenol spectra in seeds and in needles were similar. In angiosperms (25 representatives of 13 botanical families) the polyisoprenoid mixture in seeds resembled the minor, additional subfamily found in leaves.  (+info)