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At least 307 records · Page 17Linked to original sources
PubMed2004

Isolation of high-quality RNA from gymnosperm and angiosperm trees.

An improved protocol was developed for efficient and reliable extraction of high-quality total RNA and mRNA from various tissues of spruce (Picea spp.) and poplar (Populus spp.) trees, as well as other plant species. This method was specifically optimized for tissues with high content of polysaccharides, oleoresin terpenoids, and phenolic secondary metabolites, which often co-precipitate with RNA and inhibit subsequent reverse transcription. The improved protocol yielded up to 600 micrograms of total RNA per gram of tissue suitable for standard expressed sequence tags (ESTs), full-length cDNA library construction, and for microarray applications.

Chemical Fractionation↗
PubMed1999

Process and current status of the epidemiologic studies on cedar pollinosis in Japan.

This paper reviews the present situation and future aspects of epidemiologic studies on Japanese cedar pollinosis. Increase of allergic rhinitis patients is observed in both the Patient Survey and the Reports on the Surveys of Social Medical Care Insurance Services, however, these surveys are conducted when cedar pollens do not pollute the air. Many have reported on the prevalence of pollinosis in limited areas but only a few nationwide epidemiologic surveys have been conducted. Most of the studies were conducted at special medical facilities such as university hospitals. There is a high possibility that patients who visit the specific facilities do not exactly represent the actual number of patients and epidemiologic pictures of pollinosis in Japan. The rapid advances in laboratory test methods may change the diagnostic criteria and increase the number of reported patients. Therefore, the prevalence of Japanese cedar pollinosis in Japan has not been determined yet. Determination of the prevalence of cedar pollinosis and description of the epidemiologic pictures constitute the essential steps toward the control of this clinical entity. Thus it is necessary to conduct an epidemiologic survey on Japanese representative samples with a standardized survey form with clear and concise diagnostic criteria.

Allergens↗
PubMed2003

Effects of sago starch content in the diet on lipid peroxidation and antioxidative enzyme activities in rats.

The effects of sago starch content in diets on the status of lipid peroxidation and antioxidative enzyme activities were examined with rats fed cholesterol-free and cholesterol-enriched diets. Despite the diets with and without supplemental cholesterol, both food intake and the value of plasma thiobarbituric acid reactive substances (TBARS) showed a lower tendency or lower values in the rats fed the diet with a high ratio of sago starch as compared to a low ratio. Liver superoxide dismutase (SOD) and catalase activities, and serum and liver alpha-tocopherol concentrations were higher in the rats fed the cholesterol-free and enriched diets with a high ratio of sago starch as compared to a low ratio. From these results, it was suggested that a higher ratio of sago starch in the diet may be useful to keep the in vivo oxidative status at a lower level.

Animals↗
PubMed1999

Two highly divergent 5S rDNA unit size classes occur in composite tandem array in European larch (Larix decidua Mill.) and Japanese larch (Larix kaempferi (Lamb.) Carr.).

The 5S ribosomal DNA unit structure and organization have been investigated in Larix decidua and Larix kaempferi using selective amplification of gene and spacer, sequence analysis and homologous probe hybridization. Two highly divergent unit size classes of approximately 650 and 870 bp were detected in both species. Sequence analysis in Larix decidua revealed that length variations occur in the middle spacer region and are the result of duplications (in the long spacers) and considerable sequence heterogeneity. Conversely, the transcribed region is of uniform length (120 bp), and the nucleotide sequence of one Larix decidua clone is similar to that reported for other gymnosperms. Sequence comparison of the larch spacers with two other Pinaceae species (Pinus radiata and Picea glauca) showed that the 5' and 3' regions flanking the gene (40 and 60 bp, respectively) are quite conserved, suggesting a regulatory role. Moreover, a small element of about 70 bp located in the middle spacer region was found to be common to the larch long units and the six Pinus radiata spacer clones previously sequenced (64% sequence identity). The short and long unit size classes are mainly organized in composite tandem array(s) with evidence of extensive zones of strict alternation in both species. Mechanisms underlying this unusual association of divergent units in larch 5S rDNA arrays are discussed.

Base Sequence↗
PubMed1997

[Chemical constitutents of Podocarpus imbricatus BI. (II)].

From Podocarpus imbricatus five compounds were isolated and identified as 2"-O-rhamnosylvitexin (I), hinokiflavone (II), ecdysterone (III), beta-sitosteryl heptadecoate (IV) and daucosterol(V) on the basis of spectral studies (UV, IR, 1HNMR, 13CNMR, MS) and chemical reactions. I, II, III, IV are obtained from this plant for the first time, and IV is obtained as beta-sitosteryl odd number carboxylic ester for the first time.

Biflavonoids↗
PubMed1997

[Chemical constituents of Cistanche tubulosa (Schenk) Wight].

From the dry bulbs of Cistanche tubulosa six compounds were isolated and identified as beta-sitosterol, D-mannitol, daucosterol, succinic acid, D-glucose and D-fructose by spectral and chemical analyses. All of them were isolated from the plant for the first time.

Cycadopsida↗
PubMedDate not supplied

[A source of high frequency variations in the tracheid size in annual tree rings of conifers].

Statistical analysis of high-frequency variations in the radial dimensions of tracheids was carried out using precise measurements of five radial rows in each annual tree ring for several coniferous species: Larix gmelinii, L. leptolepis, L. sibirica, Picea abies, Pinus sylvestris, P. rigida, and P. densiflora. More than 25 tree rings with a varying number of cells and width were measured for each species. High-frequency variations in radial dimensions were found to have a regular (cyclic) characteristic and accumulated 5 to 11% of the total variability. The cyclic pattern was identified using Fourier analysis of time-related or successive series statistical procedure. The first order autocorrelations (-0.45 to -0.74) and the mean cycle of high-frequency variations (2.1-2.5) did not depend on the number of cells in the annual ring, i.e., they are determined by internal causes. The cyclic pattern of high-frequency variation in tracheid dimensions is used to interpret the seasonal mechanism of xylem formation. Specifically, (1) high-frequency variations in the tracheid radial size take place during the last asymmetrical division of the xylem mother cell before transition to the elongation zone, (2) the final tracheid radial size is mostly determined within the zone of division due to the last asymmetrical division, and (3) acceleration of cell cycle from the initial to the periphery of the cambial zone. The results obtained are also discussed with respect to the mechanisms of xylem differentiation.

Cycadopsida↗
PubMed2000

Low-copy microsatellite markers for Pinus taeda L.

Eighteen low-copy and genomic microsatellite markers were tested for Mendelian inheritance and then assayed in 41 Pinus taeda L. samples drawn from five regions in the southern United States. The PCR products had multiple alleles, high levels of polymorphism, and little non-specific priming. Fifteen of the 18 markers were informative for a P. taeda three-generation RFLP (restriction fragment length polymorphism) pedigree, and a P. taeda population survey revealed three to 28 alleles per locus. The highest allele numbers and polymorphic information content (PIC) values were associated with complex repeat sequences and (or) with sequences consisting of the longer strings of perfect repeats. The abundance of low- to rare-frequency alleles also accounted for high PIC values in both types of markers. Low-copy microsatellites are useful for the large, complex pine genome, especially in the absence of entire gene sequences in public databases and with the low levels of polymorphism in markers developed from expressed sequence tags (ESTs).

Alleles↗
PubMed1997

[GC-MS analysis of constituents of essential oils from stems of Ephedra sinica Stapf, E. intermedia Schrenk et C.A. Mey. and E. equisetina Bge].

The essential oils from the dried stems of Ephedra sinica, E. intermedia and E. equisetina were analyzed by GC-MS qualitatively and GC quantitatively. One hundred and twenty-seven constituents were identified, l-alpha-terpineol (31.64%) in E. sinica, 1,4-cineole (12.80%) in E. intermedia and hexadecanoic acid (26.22%) in E. equisetina being the main constituents.

Cycadopsida↗
PubMed2000

Allozyme diversity and population genetic structure of Pinus densata Master in northwestern Yunnan, China.

We investigated the levels and patterns of genetic diversity of Pinus densata Master in Yunnan. Horizontal starch-gel electrophoresis was performed on macrogametophytes collected from nine populations in northwestern Yunnan, China. Compared with other gymnosperm species, P. densata has higher mean values for all measures of genetic diversity. Allozyme polymorphism (0.99 criterion) was 97.0% and 71.4% at the species and population levels, respectively. The average number of alleles per locus was 3.1 and 2.0 at the species and population levels. Mean expected heterozygosity was substantially higher in P. densata than average values investigated for other gymnosperms both at the population (Hep = 0.174 +/- 0.031) and at the species (Hes = 0.190) levels. Of the total genetic variation, less than 12% was partitioned among populations (GST = 0.112). Our allozyme survey supports the suggestion that the observed higher diversity in P. densata may be attributed partly to its hybrid origin between two genetically distinct species, P. yunnanensis and P. tabulaeformis. In addition, we suggest that introgression would give rise to the increase in genetic diversity occurring in P. densata.

Alleles↗
PubMed2000

[Lipids from fossil plants and their relation to modern plants. Example s of Cenomanian flora from Anjou and Bohemia].

Comparative analyses of lipids from fossil plants and from their extant counterparts were undertaken in order to test the taxonomic significance of lipids in palaeobotany. The comparison between lipids from a fossil Ginkgoaceae, Eretmophyllum andegavense, and its extant counterpart, Ginkgo biloba, revealed the presence of original molecules, dimethoxyalkylcoumarins, in lipids from both plants. Such compounds confirm, on chemical grounds the relationship between these extant and fossil Ginkgoaceaes. Moreover, differences in n-alkane distribution between E. andegavense and E. obtusum which are very similar morphologically, confirm that these fossil plants do not belong to the same species. Furthermore, comparative analyses of a fossil Cheirolepidiaceae, Frenelopsis alata, and its extant counterpart, the Cupressaceae Tetraclinis articulata, revealed some similarities between these two species although they do not belong to the same family. Otherwise, comparative analyses of fungi-infected and uninfected samples of F. alata demonstrated that these micro-organisms can significantly affect the chemical composition of fossil plant lipids. In conclusion, even if chemical analyses alone are not sufficient to determine the genus or species of a given fossil plant, they can precise the taxonomy of some specimens that have been previously studied by palaeobotanists.

Cycadopsida↗
PubMed2000

Seasonal variations of diacylglyceryl-N,N,N-trimethylhomoserine content in Polypodiophyta.

Diacylglyceryl-N,N,N-trimethylhomoserine (DGTS) belongs to a family of three known betaine lipids. It is synthesized by a number of bacteria, fungi, brown, red and green algae, in addition to lichens, and is also found in higher plants Bryophyta, Equisetophyta and Polydiophyta. It has been determined that DGTS plants can be DGTS-positive or DGTS-negative. The purpose of the present study was to examine the leaves of the ferns Drytopteris filix-mas (L.) Tod. and Pteridium aquilinum (L.) Kuhn, collected at different time periods during a single vegetation season for their DGTS contents. The results obtained show that amounts of DGTS in all of the species examined varies relative to the time periods in which they were collected.

Cycadopsida↗
PubMed2000

Aging in Pinus sylvestris L. seeds: changes in viability and lipids.

Aging of Scots pine seeds (Pinus sylvestris L.) leads to changes in seed quality, such as loss of germinability, delayed growth and abnormality in developing seedlings. The knowledge of biochemical changes responsible for these aging processes is plentiful in some seeds, which are of world-wide interest, but for pine seeds these studies are rare. The aim of the present study, was to analyse pine seeds of varying ages in order to identify biochemical changes occurring in aged pine seeds, and to see if a correlation existed between these results and traditionally used seed-quality parameters, such as germinability and electrolyte leakage.

Cycadopsida↗
PubMed2001

Differential stress responses of antioxidative systems to drought in pendunculate oak (Quercus robur) and maritime pine (Pinus pinaster) grown under high CO(2) concentrations.

Maritime pine (Pinus pinaster), a drought-avoiding species, contained 2--4-fold lower activities of superoxide dismutase, ascorbate peroxidase, catalase, dehydroascorbate reductase, and glutathione reductase than pendunculate oak (Quercus robur), a drought-tolerant species. The levels of ascorbate, monodehydroascorbate radical reductase activity, and glutathione in pine needles were similar to those in oak leaves. In both species the development of drought stress, characterized by decreasing predawn water potentials, caused gradual reductions in antioxidant protection, increased lipid peroxidation, increased oxidation of ascorbate and glutathione and in pine also significant loss in soluble proteins and carotenoids. These results support the idea that increased drought-tolerance in oak as compared with pine is related to increased biochemical protection at the tissue level. To test the hypothesis that elevated CO(2) ameliorated drought-induced injury, young oak and pine trees acclimated to high CO(2) were subjected to drought stress. Analysis of plots of enzymatic activities and metabolites against predawn water potentials revealed that the drought stress-induced decreases in antioxidant protection and increases in lipid peroxidation were dampened at high CO(2). In pine, protein and pigment degradation were also slowed down. At high CO(2), superoxide dismutase activities increased transiently in drought-stressed trees, but collapsed in pine faster than in oak. These observations suggest that the alleviation of drought-induced injury under elevated CO(2) is related to a higher stability of antioxidative enzymes and an increased responsiveness of SOD to stressful conditions. This ameliorating mechanism existed independently from the effects of elevated CO(2) on plant water relations and is limited within a species-specific metabolic window.

Antioxidants↗
PubMed2000

Different classes of retrotransposons in coniferous spruce species.

We have used the conservation of reverse transcriptase and integrase domains among retroelements to PCR-amplify three well-known types of these mobile genetic elements. Reverse transcriptase sequences from Ty1-copia were identified in spruce in this way, as well as integrase sequences from the Ty3-gypsy group. Using these sequences as probes against a Picea glauca genomic bank, individual members from the LTR (long terminal direct repeat) groups were obtained. A partial Ty1-copia-type element named Spcl was isolated along with a Ty3-gypsy-type element named Spdl. Genomic Southern hybridizations revealed the complexity and high copy number of LTR retrotransposons in black and white spruce.

Amino Acid Sequence↗
PubMedDate not supplied

[Radiation-population monitoring of Pinus sylvestris L. in the zone of the Chernobyl power plant].

Cytogenetic and genetic effects in populations of Pinus sylvestris L. suffered wiak, average, strong and sublethal radiation damage after the Chernobyl accident in 1986 were studied. The absorbed dozes for trees in these plantings were from 0.1 up to 20 Gy. It was shown that the amount of cells with chromosome aberrations in sprouts of seeds of a crop of 1993, are comparable with effects marked at once after accident in 1986. In 1997 and in 1998 the amount of cells with chromosome aberrations in sprouts of seeds in majority inspected plantings decreased to control values. The effect of adaptation was detected, when seeds of Pinus sylvestris L., gathered in 1997 from inspected trees, were exposed to additional 4 Gy gamma-radiation.

Chromosome Aberrations↗
PubMed2001

A comparison of three methods for determining the stomatal density of pine needles.

Alternative methods were compared for determining the stomatal density of needles from two pine species. Densities estimated from air-dried, whole needles using a binocular dissecting scope were compared to densities estimated from vacuum-dried, intact needles using a scanning electron microscope and expanded peels (or macerated cuticles) using a compound light microscope. Differences among methods were expected from two sources: (1) expansion and shrinkage as a function of water content, and (2) differences in geometry of the measured surface. Estimates from the dissecting scope were similar to those from scanning electron microscopy (t=0.509, n=21, P:=0.62), presumably because both used dried, but otherwise intact whole needles. Light microscopy estimates, however, were lower than dissecting scope estimates (t=-2.307, n=13, P:=0.04). After adjusting for expansion due to hydration and changes in needle geometry, differences disappeared (t=-1.205, n=13, P:=0.25). These results are an important consideration for researchers reconstructing palaeo-atmospheric conditions and assessing plant response to environmental change.

Botany↗