Thesis (Ph. D.)--University of Chicago, Dept. of Molecular Genetics and Cell Biology, June 2001. / Includes bibliographical references. Also available on the Internet.

Reproduction de : Thèse de doctorat : Sciences Naturelles : Faculté des sciences de Paris : 1879. / Titre provenant de la page de titre du document numérisé.

No description available.

Previously published descriptions of the pollen morphology of the Palmae are reviewed and discussed. The earliest macro fossil records for palms are summarised, while a more detailed review is given of the fossil records of palmlike pollen. Selected literature relating to pollen sharing some similarities to palm pollen in other monocotyledonous families are briefly reviewed, and the fossil pollen records for these families are examined. A brief chronological account of earlier systematic treatments of the palms is provided, as well as an outline of the systematic treatment of the family used in the present account. The pollen morphology of 1150 collections, representing 765 species of palms,f rom all but seveno f the currentlyr ecognisedg enera,h asb eene xamýined, as well as dispersedp alm-likef ossil pollen from the middle Eoceneo f the Isle of Wight, and of Java. Iii silit pollen of fossil palm flowers from the Messel oil shales (Germany)a re describedP. ost meiotic tetrad stageh asb eens tudiedf or representatives peciesin all subfamiliese xceptingt he PhytelephantoideaeP.o llen morphologyo f both recenta nd fossil pollen is describedf rom light, scanning electrona nd, selectivelyf rom transmissione lectronm icroscopy,w hile tetrad resultsa re from light and scanninge lectronm icroscopy.F ull detailso f preparation methods,t erminologya nd databaseus sedf or pollen morphological,f ossil and tetrad studies are given. Seventeena perturet ypes,p lus numerouss ubtypesa, nd twelve exine types with numerous subtypes are identified. The aperture types are shown to be broadly separablein to two groupsw hich are associatedw ith either simultaneous (tetrahedralt etrads)o r successive(t etragonalt etrads)m icros porogenessi. In generalt heset wo groups supportp resents ystematico pinion regardingt he subfamilies.S uccessivem eiosisi s dominanti n subfamiliesC alamoideaea nd Nypoideaew hile, with somer are exceptionss, imultaneousm eiosisp redominates in the remainingf our subfamiliesC: oryphoideaeC, eroxyloideaeA, recoideaea nd PhytelephantoideaeP.o llenu ltrastructurei s treatedi n detail only for simple tectate exines where it is important for further definition. Six types and a number of subtypesa re described.T he systematicd istributionso f aperturea nd exine types are summarisedA. trend towardsl arger pollen is noted, with the smallest pollen occurring in the least specialised subfamily, the Coryphoideae, while very large-sized pollen are characteristic of subfamily Phytelephantoideae. Monosulcate, disulcate and zonosulcate pollen are described from fossil material and closest affinities with recent palms suggested. Pollen morphology of recent palms is summarised and discussed, and compared with pollen of selected monocotyledonous families. The bearing of pollen data on recent palm systematics is considered at various levels from subfamily to species. Angiosperm pollen evolution is re-considered and evolutionary pathways for palm pollen aperture types and exine types are suggested. In the light of recent pollen morphology for the family the fossil record of palm pollen is re-evaluated. Some widely accepted affinities are challenged while previously unconsidered affinities are suggested, particularly for the mid- Cretaceous. The need is emphasized for future fossil pollen studies to look critically for pre Late Cretaceous palm-like monosulcates, which would be more informative of the early history of the family than the apparently highly evolved, easily recognisable Spini. -onocolpiles of the Late Cretaceous. Palaeogeography, environment and distribution of fossil records and depositional environment are discussed. Probable evolutionary pathways of pollen morphology, including pollen tetrad data which suggests imultaneousra thert han successivem eiosisa s the plesiomorphics tate,o ffer further evidencet hat the palmsa re indeeda n ancient group, and support the hypothesis that the palms may have originated in South America and Africa (West Gondwana)in the Late Jurassic or early Cretaceous, prior to the complete separation of these continents.

The aim of this research was to study the effects of Salinity & Heavy Metals on the Sporophyte & Gametophyte generations of Arabidopsis thaliana. After developing a pollen germinating protocol, some basic experiments were conducted to determine the effects on chemical & physical parameters on pollen germination & pollen tube growth. Additions of heavy metals & high concentrations of buffer (Tris-HCI) in pollen germinating medium (PGM), inhibited pollen germination (PG) & pollen tube length (PTL), while pH range (7.0-9.0) had little effect. The idea of 2-fold effect (nutritional & osmotic) of sucrose was supported in results. In vivo pollen growth was much greater than in vitro & genotypic differences occurred among the mutants for PG & PTL. Comparing the pollen nutritional requirements for PG & PTL between Cicer arietinum & A. thaliana, it was noted that the pollen of the former had a greater requirement for H(_3)BO(_3) & Ca(N0(_3))(_2) than latter. The range of temperatures (0 C-35 C) studied, indicated that the most favourable temperature for PG was 20 C & for PTL 25 C , while extreme temperatures (0 C, 35 C) were harmful to A. thaliana pollen. 20 C was found to be optimum temperature for PG & PTL of C. arietinum. Correlation between pollen tube growth rates (PTGRs) and sporophytic traits of Fls showed a generally strong positive correlation with most of sporophytic traits, but a very loose to negative correlation for earliness parameters. Recording the impacts of salinity, parallel effects were found for the sporophytic & gametophytic generations of the plant, as reported by earlier workers. The results also indicated that it is possible to develop a pollen plant salinity index (PPSI) for plant species under specific plant growing conditions. It was also observed that salinity stress during pollen gametogenesis preconditioned pollen to high salinity levels, resulting in higher PG & PTL than in pollen raised under non-saline conditions. Similarly, the fruit-setting, seed-setting & seed-filling were relatively less affected by saline-stress, in progeny when pollen and pistilate plants were grown under similar saline regimes. Anatomical studies showed that salinity induced changes in the epidermis, cortex, pericycle, xylem, pith & cross sectional diameter of vascular bundle (CSDVB) in stem, leaf & root tissues. Lower reductions for the fruit-setting, seed-setting & seed-filling were recorded in response to the high heavy metal concentrations in progeny when pollen and pistilate plants were raised under similar heavy metal regimes. It was apparent that pollen become conditioned to a stress environment during its development in the anthers of stressed plants, & this preconditioning allowed its pollen tubes to grow more successfully in the styles of the female parents growing in a similarly stressed environment, where the pistil may have accumulated higher levels of heavy metals. Heavy metals induced changes in stem shape, epidermis, cortex, vascular bundles & chloroplasts in stems. The metals induced changes in the leaf thickness, epidermis, palisade cell size, spongy mesophyll area, size of intercellular spaces & chloroplasts in the leaf, causing disruption of cortical layers, lignification of pericycle & phloem, damage to the endodermis and increase in xylem cell size & stele diameter in roots.

No description available.

Pollen grains are ubiquitous triggers of allergic asthma and seasonal rhinitis. Proteolytic enzymes in pollen as well as other sources are capable of disrupting airway epithelial integrity in vivo and in vitro. This provides a plausible mechanism for the initiation of sensitisation of the respiratory immune system to inhaled pollen allergens, comparable to that suggested for Group 1 allergens from house dust mites and cat dander, which are known to possess intrinsic proteolytic activity. This thesis explores the relationship between pollen allergens and proteolytic enzymes. It describes the different strategies used for the characterisation, purification and identification of immunogenic and proteolytic proteins in the complex mixtures of pollen diffusates. The peptidases in the diffusates of Kentucky blue grass, ryegrass and Bermuda grass pollens were characterised by a sensitive fluorescence assay and gelatin zymography. Among these, Bermuda grass pollen demonstrated the presence of a serine peptidase at Mr ~30,000 Da, which corresponded to an intense band by Western blotting using a monoclonal antibody to the timothy grass (Phleum pratense) group 1 allergen, Phl p 1. Purification of this enzyme from Bermuda grass was complicated by the low levels of the enzyme present in the diffusate, as well as by its autohydrolysis. Partial purification of the serine peptidase activity by affinity chromatography using Concanavalin A Sepharose demonstrated that the diffusate contained a trypsin-like peptidase, detected by the fluorescent assay, in addition to the ~30,000 Da serine endopeptidase, detected on gelatin zymography. Proteomic analysis of the ~30,000 Da protein using one- and two-dimensional electrophoresis and mass spectrometry identified it as the major pollen allergen of Bermuda grass, Cyn d 1. The studies reported here provide, for the first time, evidence that a pollen allergen may possess intrinsic proteolytic activity. This activity may play a role in the initiation of airway inflammation and allergic sensitisation.

Bibliography: leaves 124-136 / xviii, 136 leaves, [22] leaves of plates : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Agricultural Biochemistry, 1986

Pollen grains are ubiquitous triggers of allergic asthma and seasonal rhinitis. Proteolytic enzymes in pollen as well as other sources are capable of disrupting airway epithelial integrity in vivo and in vitro. This provides a plausible mechanism for the initiation of sensitisation of the respiratory immune system to inhaled pollen allergens, comparable to that suggested for Group 1 allergens from house dust mites and cat dander, which are known to possess intrinsic proteolytic activity. This thesis explores the relationship between pollen allergens and proteolytic enzymes. It describes the different strategies used for the characterisation, purification and identification of immunogenic and proteolytic proteins in the complex mixtures of pollen diffusates. The peptidases in the diffusates of Kentucky blue grass, ryegrass and Bermuda grass pollens were characterised by a sensitive fluorescence assay and gelatin zymography. Among these, Bermuda grass pollen demonstrated the presence of a serine peptidase at Mr ~30,000 Da, which corresponded to an intense band by Western blotting using a monoclonal antibody to the timothy grass (Phleum pratense) group 1 allergen, Phl p 1. Purification of this enzyme from Bermuda grass was complicated by the low levels of the enzyme present in the diffusate, as well as by its autohydrolysis. Partial purification of the serine peptidase activity by affinity chromatography using Concanavalin A Sepharose demonstrated that the diffusate contained a trypsin-like peptidase, detected by the fluorescent assay, in addition to the ~30,000 Da serine endopeptidase, detected on gelatin zymography. Proteomic analysis of the ~30,000 Da protein using one- and two-dimensional electrophoresis and mass spectrometry identified it as the major pollen allergen of Bermuda grass, Cyn d 1. The studies reported here provide, for the first time, evidence that a pollen allergen may possess intrinsic proteolytic activity. This activity may play a role in the initiation of airway inflammation and allergic sensitisation.

Ulm, Univ. Diss., 2006.