Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Pinaceae”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed2004

Oviposition strategies of conifer seed chalcids in relation to host phenology.

Insects are considered the most important predators of seed cones, the female reproductive structures of conifers, prior to seed dispersal. Slightly more than 100 genera of insects are known to parasitize conifer seed cones. The most diverse (i.e., number of species) of these genera is Megastigmus (Hymenoptera: Torymidae), which comprises many important seed pests of native and exotic conifers. Seed chalcids, Megastigmus spp., lay eggs inside the developing ovules of host conifers and, until recently, oviposition was believed to occur only in fertilized ovules. Ovule development begins just after pollination, but stops if cells are not fertilized. The morphological stage of cone development at the time of oviposition by seed chalcids has been established for many species; however, knowledge of ovule development at that time has been documented for only one species, M. spermotrophus. Megastigmus spermotrophus oviposits in Douglas-fir ovules after pollination but before fertilization. Unlike the unfertilized ovules, those containing a M. spermotrophus larva continue to develop, whether fertilized or not, stressing the need to broaden our understanding of the insect-plant interactions for this entire genus. To achieve this task, we reviewed the scientific literature and assembled information pertaining to the timing of oviposition and to the pollination and fertilization periods of their respective host(s). More specifically, we were searching for circumstantial evidence that other species of Megastigmus associated with conifers could behave (i.e., oviposit before ovule fertilization) and impact on female gametophyte (i.e., prevent abortion) like M. spermotrophus. The evidence from our compilation suggests that seed chalcids infesting Pinaceae may also oviposit before ovule fertilization, just like M. spermotrophus, whereas those infesting Cupressaceae seemingly oviposit after ovule fertilization. Based on this evidence, we hypothesize that all species of Megastigmus associated with Pinaceae can oviposit in unfertilized ovules, whereas those exploiting Cupressaceae cannot, and thus oviposit only in already fully developed fertilized seeds. Furthermore, we predict that the presence of a larva in unfertilized ovules of all Pinaceae will influence the development of the female gametophyte by preventing its abortion. This influence on the Pinaceae can be interpreted as an ability to parasitize any of the potential seeds present in a seed cone, and as such represents a much more efficient oviposition strategy than searching and locating only fertilized seeds. Concomitantly, this ability has likely led to an overestimation of the impact of the species of seed chalcid infesting Pinaceae on seed production.

Animals↗
PubMed2000

Cross-reactivity among conifer pollens.

BACKGROUND: There are increasing reports of Cupressaceae pollinosis from various geographic areas. Cross-reactivity among a limited number of species within the Cupressaceae family has been suggested. Juniperus ashei (mountain cedar) is the leading cause of respiratory allergy in South Texas. OBJECTIVE: This study examines in vivo and in vitro cross-reactivity among 12 Cupressaceae species, one Taxodiaceae species, one Pinaceae species, and an angiosperm. METHODS: Cross-reactivity among pollen extracts of mountain cedar (MC) and the other 14 trees was investigated by: (1) prick skin testing of each tree pollen extract in ten patients with MC pollinosis. (2) Ouchterlony gel immunodiffusion employing rabbit antisera to MC. (3) IgE immunoblotting using high-titer MC pooled human sera, and immunoblot inhibition after pre-incubation with MC protein. (4) Monoclonal antibody immunoblotting using a murine monoclonal antibody with strong affinity for the gp40 major allergen of MC. RESULTS: Positive skin wheal-and-flare responses occurred to all 12 Cupressaceae and Japanese cedar (the Taxodiaceae), but not to the Pinaceae or the angiosperm. In Ouchterlony gels, lines of identity or partial identity formed between MC and all pollens except the Pinaceae and the angiosperm. Immunoblots demonstrated IgE binding to the 40 to 42 kD protein in each Cupressaceae, and to a parallel band in Japanese cedar at 43 to 46 kD. Immunoblot inhibition by MC pollen was complete for all trees. The monoclonal bound both the 40 to 42 kD protein in 11 of 12 Cupressaceae species and the 46 kD band in Japanese cedar, but bound no protein bands in the Pinaceae or the angiosperm. CONCLUSION: Pollen proteins of the 12 Cupressaceae (including MC) and the Taxodiaceae (Japanese cedar) are extensively cross-reactive. In particular, the MC major allergen, gp40, is cross-reactive with 40 to 42 kD proteins of the other Cupressaceae and with the Japanese cedar major allergen of 46 kD. Component-based immunotherapy may someday allow a standard treatment for both Juniper-allergic and C. japonica-allergic patients.

Animals↗
PubMed2001

Taxonomy of gymnospermae: multivariate analyses of leaf fatty acid composition.

The fatty acid composition of photosynthetic tissues from 137 species of gymnosperms belonging to 14 families was determined by gas chromatography. Statistical analysis clearly discriminated four groups. Ginkgoaceae, Cycadaceae, Stangeriaceae, Zamiaceae, Sciadopityaceae, Podocarpaceae, Cephalotaxaceae, Taxaceae, Ephedraceae and Welwitschiaceae are in the first group, while Cupressaceae and Araucariaceae are mainly in the second one. The third and the fourth groups composed of Pinaceae species are characterized by the genera Larix, and Abies and Cedrus, respectively. Principal component and discriminant analyses and divisive hierarchical clustering analysis of the 43 Pinaceae species were also performed. A clear-cut separation of the genera Abies, Larix, and Cedrus from the other Pinaceae was evidenced. In addition, a mass analysis of the two main chloroplastic lipids from 14 gymnosperms was performed. The results point to a great originality in gymnosperms since in several species and contrary to the angiosperms, the amount of digalactosyldiacylglycerol exceeds that of monogalactosyldiacylglycerol.

Abies↗
PubMedDate not supplied

Electrophoretic analysis of seed storage proteins from gymnosperms.

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), pore gradient gel electrophoresis (PGGE) followed by SDS-PAGE and Western blot analysis were used to characterize the seed storage proteins from seven gymnosperm species from the families Pinaceae (Abies alba, Cedrus atlantica and Picea abies), Cupressaceae (Biota orientalis, Chamaecyparis lawsoniana and Cupressus arizonica), and Taxaceae (Taxus baccata). SDS-PAGE and PGGE X SDS-PAGE indicate the presence of proteins with characteristics similar to the 7S globulins in all the species studied. Antibodies to a 7S globulin subunit from Pinus pinaster cross-reacted with homologous polypeptides from Pinaceae species, but not with corresponding subunits from species belonging to other families. Also detected in each of the studied species, with the exception of A. alba and T. baccata, were those of C. atlantica may be extracted by saline buffer, while the remainder require a dissociating agent. Antibodies raised against the small subunit from P. pinaster 11S protein recognized only the corresponding polypeptides from Pinaceae species. Overall, these results help clarify our knowledge of gymnosperm seed storage proteins.

Animals↗
PubMed2002

The evolution of gymnosperms redrawn by phytochrome genes: the Gnetatae appear at the base of the gymnosperms.

Gymnosperms possess two to four phytochrome types which apparently are the result of successive gene duplications in the genomes of their common ancestors. Phytochromes are nuclear-encoded proteins whose genes, contrary to chloroplast, mitochondrion, and rRNA genes, have hitherto rarely been used to examine gymnosperm phylogenies. Since the individual phytochrome gene types implied phylogenies that were not completely congruent to one another, conflicting branching orders were sorted by the number of gene lineages present in a taxon. The Gnetatae (two gene types) branched at the base of all gymnosperms, a position supported by bootstrap sampling (distance and character state trees, maximum likelihood). The Gnetatae were followed by Ginkgo, Cycadatae, and Pinaceae (three gene types) and the remaining conifers (four gene types). Therefore, in phytochrome trees, the most ancient branch of the conifers (Pinatae) seems to be the Pinaceae. The next split appears to have separated Araucariaceae plus Podocarpaceae from the Taxaceae/Taxodiaceae/Cupressaceae group. Structural arrangements in the plastid genomes (Raubeson and Jansen 1992) corroborate the finding that there is no close connection between Pinaceae and Gnetatae as suggested by some publications. The analyses are based on 60 phytochrome genes (579 positions in an alignment of PCR fragments) from 28 species. According to rough divergence time estimates, the last common ancestor of gymnosperms and angiosperms is likely to have existed in the Carboniferous.

Cycadopsida↗
PubMed2000

Seed plant phylogeny inferred from all three plant genomes: monophyly of extant gymnosperms and origin of Gnetales from conifers.

Phylogenetic relationships among the five groups of extant seed plants are presently quite unclear. For example, morphological studies consistently identify the Gnetales as the extant sister group to angiosperms (the so-called "anthophyte" hypothesis), whereas a number of molecular studies recover gymnosperm monophyly, and few agree with the morphology-based placement of Gnetales. To better resolve these and other unsettled issues, we have generated a new molecular data set of mitochondrial small subunit rRNA sequences, and have analyzed these data together with comparable data sets for the nuclear small subunit rRNA gene and the chloroplast rbcL gene. All nuclear analyses strongly ally Gnetales with a monophyletic conifers, whereas all mitochondrial analyses and those chloroplast analyses that take into account saturation of third-codon position transitions actually place Gnetales within conifers, as the sister group to the Pinaceae. Combined analyses of all three genes strongly support this latter relationship, which to our knowledge has never been suggested before. The combined analyses also strongly support monophyly of extant gymnosperms, with cycads identified as the basal-most group of gymnosperms, Ginkgo as the next basal, and all conifers except for Pinaceae as sister to the Gnetales + Pinaceae clade. According to these findings, the Gnetales may be viewed as extremely divergent conifers, and the many morphological similarities between angiosperms and Gnetales (e.g., double fertilization and flower-like reproductive structures) arose independently.

Cycadopsida↗
PubMed2004

Induction of anatomically based defense responses in stems of diverse conifers by methyl jasmonate: a phylogenetic perspective.

Conifers have evolved constitutive and inducible defense mechanisms to help in both wound healing and defense against attack by bark beetles and other organisms. These defenses include oleoresin, phenolics, and static structures in secondary phloem, such as lignified cells and calcium oxalate crystals, that create physical barriers. We used a phylogenetic approach to investigate the defense anatomy of conifer stems of 13 species from five families following treatment with methyl jasmonate (MJ), a compound that induces defense responses in stems of several Pinaceae species. Methyl jasmonate induced a response similar to wounding except that the response was not accompanied by lesion formation, necrosis or a hypersensitive response. In the Pinaceae species studied, MJ induced polyphenolic parenchyma (PP) cell activation and xylem traumatic resin duct (TD) formation. Members of the Taxodiaceae, which are not known to produce large quantities of resin, showed massive xylem TD formation and surface resinosis following MJ treatment. Treatment with MJ caused members of the Araucariaceae and Cupressaceae to form axial phloem resin ducts but not xylem ducts, whereas Podocarpaceae species showed no induction of resin-producing structures. All species treated with MJ showed phenolic deposition in PP cells, and early lignification of phloem fibers was observed in most of the non-Pinaceae species. We conclude that, although evolution of resin-producing structures occurred independently in conifer lineages, MJ seems to induce resin production regardless of tissue location, as well as inducing deposition of phenolic compounds. Co-evolution of conifer defensive strategies and bark beetle pests is discussed.

Acetates↗
PubMed2004

Airborne pollen calendar of Lublin, Poland.

Pollen concentration in the atmosphere of Lublin (eastern Poland) was studied by means of volumetric method using Hirst sampler (VPPS 2000, Lanzoni) in 2001-2002. The pollen trap was mounted at the height of 15 m in the centre of Lublin. On the basis of analysis of mean daily values of pollen concentration, the pollen calendar was constructed for 16 taxa producing the allergenic pollen: Alnus, Corylus, Populus, Ulmus, Fraxinus, Betula, Carpinus, Quercus, Fagus, Pinaceae, Poaceae, Rumex, Plantago, Chenopodiaceae, Artemisia, Urticaceae. Great differences referring to the course of pollen seasons for most of the studied taxa of trees within the 2 years of study were found. They were associated with the beginning and end of the pollen season, the amount and the date of maximum pollen concentration occurrence, as well as annual sums of pollen grains. Much lower differentiation was observed in the case of herbaceous plants. This referred mainly to maximum concentration occurrence dates (Urtica, Poaceae) and the length of pollen season (Chenopodiaceae). The most similar course of pollen seasons during 2 years was recorded for Artemisia. Among trees, the highest pollen concentrations were recorded for Betula, Pinaceae and Alnus; the lowest for Ulmus, Fagus and Corylus. Very high concentration of herbaceous plant's pollen was observed for Poaceae and Urtica; Plantago and Chenopodiaceae showed the lowest level. Annual sums of pollen grains for Alnus, Populus, Quercus, Betula and Pinaceae were much higher in 2001, but in the case of Ulmus, Fraxinus, Carpinus, Fagus the annual sums of pollen grains in 2002 were almost twice as high as in 2001. For 5 among 7 herbaceous taxa, annual sums of pollen grains in both years were similar.

Air Pollutants↗
PubMed1995

The phylogenetic positions of the conifer genera Amentotaxus Phyllocladus, and Nageia inferred from 18S rRNA sequences.

To determine the evolutionary positions of the conifer genera Amentotaxus, Phyllocladus, and Nageia, we obtained 18S rRNA sequences from 11 new taxa representing the major living orders and families of gymnosperms. With the published Chlamydomonas as an outgroup, phylogenetic analyses of our new data and available sequences indicate that (1) the Gnetales form a monophyletic group, which is an outgroup to the conifers, (2) the conifers are monophyletic, (3) Taxaceae, Cephalotaxaceae, Cupressaceae, and Taxodiaceae form a monophyletic group, (4) Amentotaxus is closer to Torreya than to Cephalotaxus, suggesting that Amentotaxus is better to be classified as a member of Taxaceae, (5) Phyllocladus, Dacrycarpus, Podocarpus, and Nageia form a monophyletic group, and (6) Pinaceae is an out-group to the other families of conifers. Our finding that Phyllocladus is a sister group of the Podocarpaceae disagrees with the suggestion that the phylloclade of the genus is an ancient structure and that the genus is a terminal taxon within the Podocarpaceae. The genus Nageia is more closely related to Podocarpus than to Dacrycarpus and was derived from within the Podocarpaceae. In conclusion, our data indicate that in conifers, the uniovulate cone occurred independently in Taxacaeae and Cephalotaxaceae, and in Podocarpaceae after the three families separated from Pinaceae, and support the hypothesis that the uniovulate cone is derived from reduction of a multiovulate cone.

DNA, Complementary↗
PubMed1993

The phylogenetic position of Taxaceae based on 18S rRNA sequences.

The evolutionary position of the yew family, Taxaceae, has been very controversial. Some plant taxonomists strongly advocate excluding Taxaceae from the conifer order and raising its taxonomic status to a new order or even class because of its absence of seed cones, contrary to the case in the majority of conifers. However, other authors believe that the Taxaceae are not fundamentally different from the rest of the conifers except in that they possess the most reduced solitary-ovule cones. To resolve the controversy, we have sequenced the 18S rRNA genes from representative gymnosperms: Taxus mairei (Taxaceae), Podocarpus nakaii (Podocarpaceae), Pinus luchuensis (Pinaceae), and Ginkgo biloba (Ginkgoales). Our phylogenetic analysis of the new sequence data with the published 18S rRNA sequence of Zamia pumila (a.cycad) as an outgroup strongly indicates that Taxus, Pinus, and Podocarpus form a monophyletic group with the exclusion of Ginkgo and that Taxus is more closely related to Pinus than to Podocarpus. Therefore, Taxaceae should be classified as a family of Coniferales. Our finding that Taxaceae, Pinaceae, and Podocarpaceae form a clade contradicts both the view that the uniovulate seed of Taxaceae is a primitive character and the view that the Taxaceae are descendants of the Podocarpaceae. Rather, the uniovulate seed of Taxaceae and that of some species of Podocarpus appear to have different origins, probably all reduced from multiovulate cones.

Base Sequence↗
PubMed2000

General characteristics of Pinus spp. seed fatty acid compositions, and importance of delta5-olefinic acids in the taxonomy and phylogeny of the genus.

The delta5-unsaturated polymethylene-interrupted fatty acid (delta5-UPIFA) contents and profiles of gymnosperm seeds are useful chemometric data for the taxonomy and phylogeny of that division, and these acids may also have some biomedical or nutritional applications. We recapitulate here all data available on pine (Pinus; the largest genus in the family Pinaceae) seed fatty acid (SFA) compositions, including 28 unpublished compositions. This overview encompasses 76 species, subspecies, and varieties, which is approximately one-half of all extant pines officially recognized at these taxon levels. Qualitatively, the SFA from all pine species analyzed so far are identical. The genus Pinus is coherently united--but this qualitative feature can be extended to the whole family Pinaceae--by the presence of delta5-UPIFA with C18 [taxoleic (5,9-18:2) and pinolenic (5,9,12-18:3) acids] and C20 chains [5,11-20:2, and sciadonic (5,11,14-20:3) acids]. Not a single pine species was found so far with any of these acids missing. Linoleic acid is almost always, except in a few cases, the prominent SFA, in the range 40-60% of total fatty acids. The second habitual SFA is oleic acid, from 12 to 30%. Exceptions, however, occur, particularly in the Cembroides subsection, where oleic acid reaches ca. 45%, a value higher than that of linoleic acid. Alpha-linolenic acid, on the other hand, is a minor constituent of pine SFA, almost always less than 1%, but that would reach 2.7% in one species (P. merkusii). The sum of saturated acids [16:0 (major) and 18:0 (minor) acids principally] is most often less than 10% of total SFA, and anteiso-17:0 acid is present in all species in amounts up to 0.3%. Regarding C18 delta5-UPIFA, taxoleic acid reaches a maximum of 4.5% of total SFA, whereas pinolenic acid varies from 0.1 to 25.3%. The very minor coniferonic (5,9,12,15-18:4) acid is less than 0.2% in all species. The C20 elongation product of pinolenic acid, bishomo-pinolenic (7,11,14-20:3) acid, is a frequent though minor SFA constituent (maximum, 0.7%). When considering C20 delta5-UPIFA, a difference is noted between the subgenera Strobus and Pinus. In the former subgenus, 5,11-20:2 and sciadonic acids are < or =0.3 and < or =1.9%, respectively, whereas in the latter subgenus, they are most often > or =0.3 and > or =2.0%, respectively. The highest values for 5,11-20:2 and sciadonic acids are 0.5% (many species) and 7.0% (P. pinaster). The 5,11,14,17-20:4 (juniperonic) acid is present occasionally in trace amounts. The highest level of total delta5-UPIFA is 30-31% (P. sylvestris), and the lowest level is 0.6% (P. monophylla). Uniting as well as discriminating features that may complement the knowledge about the taxonomy and phylogeny of pines are emphasized.

Cycadopsida↗
PubMed2004

Speciation by host-switching in pinyon Cinara (Insecta: Hemiptera: Aphididae).

Parasite-host cospeciation has received much attention as an important mechanism in the diversification of phytophagous insects. However, studies have shown that for certain taxa, it is not host fidelity but host-switching that plays the critical role in speciation. Cinara are aphids (Insecta: Hemiptera: Aphididae: Lachninae) that feed exclusively on the woody parts of conifers of the Cupressaceae and Pinaceae. They are unusual aphids because most Pinaceae play host to several species of Cinara. The aphids show relatively strong host fidelity, and as a consequence historically have been treated based on the taxonomy of their hosts. The historical paradigm of aphid evolution implies that Cinara species have radiated to different parts of the same host species and/or speciated with their host. Using mitochondrial cytochrome oxidase 1 and nuclear elongation factor 1-alpha DNA sequences, we performed molecular phylogenetic analysis of Cinara species, concentrating on those associated with pinyon pines in the southwestern USA. We determined that switching hosts has played a key role in the speciation of the genus, reflected in the polyphyly of pinyon-feeding Cinara. Furthermore, species sharing a common feeding site on different hosts were more closely related to each other than to those sharing the same host but at different feeding sites, suggesting that feeding site fidelity plays a more important role in speciation than does host fidelity in general. This study also elucidated the primary taxonomy of various species: it suggested that Cinara rustica Hottes is a junior synonym of C. edulis (Wilson) and that C. wahtolca Hottes represents two species on the two different pinyon pine species, Pinus edulis Englem. and P. monophylla Torr. & Frem.

Animals↗
PubMed2001

Cancer chemopreventive agents, serratane-type triterpenoids from Picea jezoensis.

Seven serratane-type triterpenoids isolated from the cuticle of Picea jezoensis (Sieb. et Zucc.) Carr. jezoensis (Pinaceae) and the stem bark of Picea jezoensis (Sieb. et Zucc.) Carr. hondoensis (Mayer) Rehder (Pinaceae) were studied their possible inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). All compounds showed strong inhibitory effects on the EBV-EA activation, being stronger than that of oleanolic acid, which exerts on cancer preventive activity in animal carcinogenesis models. Among these compounds, 13alpha, 14alpha-epoxy-3beta-methoxyserratan-21beta-ol and 3beta-methoxy-21alpha-hydroxyserrat-14-en-29-al were investigated for the inhibitory effects in a two-stage mouse skin carcinogenesis test on mouse skin using 7,12-dimethylbenz[a]anthracene as initiator and TPA as promoter. 13alpha,14alpha-Epoxy-3beta-methoxyserratan-21beta-ol was found to exhibit the excellent anti-tumor promoting activity in the in vivo carcinogenesis test.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2003

Cancer chemopreventive activity of serratane-type triterpenoids on two-stage mouse skin carcinogenesis.

Eleven serratane-type triterpenoids isolated from the stem bark of Picea jezoensis (Sieb. et Zucc.) Carr. var. jezoensis (Pinaceae) and the stem bark of Picea jezoensis (Sieb. et Zucc.) Carr. var. hondoensis (Mayer) Rehder (Pinaceae) and three synthetic analogs were studied for their possible inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). 21-Episerratenediol, serratenediol, diepiserratenediol, 3 beta-hydroxyserrat-14-en-21-one, 3 alpha-methoxy-21 beta-hydroxyserrat-14-en-16-one, 3 beta-methoxyserrat-14-en-21 beta-yl acetate, 3 alpha-methoxyserrat-14-en-21 beta-yl acetate and 3 beta-methoxyserrat-14-en-21 alpha-yl acetate demonstrated strong inhibitory effects on the EBV-EA activation without showing any cytotoxicity, their effects being stronger than that of a representative control, oleanolic acid. Furthermore, 21-episerratenediol exhibited a remarkable inhibitory effect on skin tumor promotion in an in vivo two-stage mouse skin carcinogenesis test using 7,12-dimethylbenz[a]anthracene as an initiator and TPA as a promoter. The result of the present investigation indicated that 21-episerratenediol might be valuable as a potent cancer chemopreventive agent.

Animals↗
PubMed1997

Predominant tree aeroallergens of the Washington, DC area: a six year survey (1989-1994).

OBJECTIVE: A 6-year (1989 to 1994) aerobiologic survey of the Washington DC area was performed to identify predominant area tree pollens, atmospheric concentrations, and peak flowering periods. METHODS: Aeroallergen sampling was conducted using a volumetric rotating-arm impaction Rotorod sampler (Sampling Technologies, Inc, Los Altos Hills, California). RESULTS: The Washington DC pollen calendar may begin as early as January when pollen of the Cupresseacea, Aceracea, Pinaceae, and Betulaceae are observed in small amounts. February through June encompasses the major part of our tree season with considerable overlapping of pollination periods for various trees. The Ulmaceae have two distinct pollinating times with later flowering species of elm pollinating August through October coinciding with ragweed season. April is usually the month with the highest weekly average concentrations. Each year oaks contribute more than 50% of the total tree pollen count followed by pollen of the Pinacea, Cupresseacea, Moracea, and Betuleacea. Times for onset of pollination as well as peak atmospheric concentrations varied from year to year. High production years for some tree aeroallergens are low years for others. CONCLUSION: The Washington DC area is exposed to significant atmospheric concentrations of tree pollen from February through June. Establishing what area tree aeroallergens predominate with respect to their atmospheric concentrations and peak pollinating times is essential for the effective diagnosis and treatment of the tree-allergic patient.

Air Pollutants↗
PubMed2006

Combined GC/MS analytical procedure for the characterization of glycerolipid, waxy, resinous, and proteinaceous materials in a unique paint microsample.

A novel GC/MS analytical procedure for the identification of lipids, waxes, proteins, and resinous materials in the same microsample from painted works of art has been optimized. It is based on a sample multistep chemical pretreatment (solvent extractions and microwave-assisted chemolysis) that is able to separate the various organic components into different fractions, which are suitably treated and derivatized before analysis. In particular, the procedure allows the complete saponification of wax esters and the completeness of the Cannizzaro type reaction of shellac acids in conditions that are suitable also for glycerides saponification. The method was tested on reference materials for the identification of proteinaceous binders (egg, collagen, casein) on the basis of the quantitative determination of the amino acid profile and the identification of glycerolipids (linseed oil, poppy seed oil, walnut oil, and egg), plant resins (Pinaceae resins, sandarac, mastic, and dammar), animal resins (shellac), tars or pitches, and natural waxes (beeswax, carnauba wax) on the basis of the determination of fatty acid, alcohol, and hydrocarbon profiles and of significant terpenic molecular markers. The procedure was applied to the characterization of three old paint microsamples. Animal glue, egg, linseed oil, beeswax, Pinaceae resin, dammar, and shellac were the identified materials found in mixtures and recognized as original and/or restoration substances.

Journal Article↗
PubMed2000

Phylogeny of seed plants based on all three genomic compartments: extant gymnosperms are monophyletic and Gnetales' closest relatives are conifers.

Efforts to resolve Darwin's "abominable mystery"-the origin of angiosperms-have led to the conclusion that Gnetales and various fossil groups are sister to angiosperms, forming the "anthophytes." Morphological homologies, however, are difficult to interpret, and molecular data have not provided clear resolution of relationships among major groups of seed plants. We introduce two sequence data sets from slowly evolving mitochondrial genes, cox1 and atpA, which unambiguously reject the anthophyte hypothesis, favoring instead a close relationship between Gnetales and conifers. Parsimony- and likelihood-based analyses of plastid rbcL and nuclear 18S rDNA alone and with cox1 and atpA also strongly support a gnetophyte-conifer grouping. Surprisingly, three of four genes (all but nuclear rDNA) and combined three-genome analyses also suggest or strongly support Gnetales as derived conifers, sister to Pinaceae. Analyses with outgroups screened to avoid long branches consistently identify all gymnosperms as a monophyletic sister group to angiosperms. Combined three- and four-gene rooted analyses resolve the branching order for the remaining major groups-cycads separate from other gymnosperms first, followed by Ginkgo and then (Gnetales + Pinaceae) sister to a monophyletic group with all other conifer families. The molecular phylogeny strongly conflicts with current interpretations of seed plant morphology, and implies that many similarities between gnetophytes and angiosperms, such as "flower-like" reproductive structures and double fertilization, were independently derived, whereas other characters could emerge as synapomorphies for an expanded conifer group including Gnetales. An initial angiosperm-gymnosperm split implies a long stem lineage preceding the explosive Mesozoic radiation of flowering plants and suggests that angiosperm origins and homologies should be sought among extinct seed plant groups.

Cycadopsida↗
PubMed2003

Estimation of the age of extant Ephedra using chloroplast rbcL sequence data.

The distinctive gymnosperm genus Ephedra is sometimes considered to have originated over 200 million years (Myr) ago on the basis of "ephedroid" fossil pollen. In this article we estimate the age of extant Ephedra using chloroplast rbcL gene sequences. Relative rate tests fail to reject the null hypothesis of equal rates of nucleotide substitution of the rbcL sequences among three landmark lineages (Gnetales, Pinaceae, and Ginkgo). The most divergent sequences we have found in Ephedra differ by only 7 bp for an 1,110 bp region of rbcL sequence, whereas the differences among genera range from 92 to 107 bp in Gnetales and from 35 to 92 bp in Pinaceae. Using three landmark events, the age of extant Ephedra is estimated to be approximately 8-32 Myr. Our result is consistent with the current distribution of many Ephedra species in geologically recent habitats and points out difficulties in the identification of older ephedroid pollen fossils with the modern genus Ephedra.

Chloroplasts↗