Maize coleoptile microsomal vesicles showing calmodulin-stimulated ATPase activity were isolated from 4.5 day old dark grown seedlings. Calmodulin-stiirmlated ATPase activity was maximal (8 nmoles min^-1 (mg protein)^-1) at 0.35 μM, inhibited by orthovanadate (Iso=20 μM), and specific for ATP. Calmodulin affinity chromatography was used to purify this ATPase after solubilisation with Triton X-100. Calmodulin-stimulated ATPase activity was present in the purified fraction, maximal stimulation (340 nmoles min^-1 (mg protein)^-1) occurring at 0.3 μM calmodulin. After reconstitution into asolectin liposomes, maximal calmodulinstimulated ATPase activity (500 nmoles min^-1 (mg protein)^-1) occurred at 0.025 μM. Affinity chromatography using buffers containing asolectin produced true basal activities; maximal calmodulin stimulation was at 0.01 μM (100 nmoles min^-1 (mg protein)^-1). These results suggest that a calmodulin-stimulated ATPase was purified from the microsomal fraction. Inclusion of protease inhibitors (PMSF, chymostatin) during purification and electrophoresis yielded a polypeptide of 140,000 M_r, similar to the M_r of erythrocyte calmodulin-stimulated, calcium-pumping ATPase (CSCPA). Polypeptides of M_r 91,000, 77-69,000, 51,000, and 40,000 were also present. A monospecific polyclonal antibody raised against erythrocyte CSCPA recognised the 140,000 M_r polypeptide from maize, giving strong evidence that maize cells may contain a polypeptide similar to erythrocyte CSCPA. The reaction mechanism of the proposed maize CSCPA was investigated. After purification in the presence of PMSF phosphorylation was present at 140,000 M_r; this turned over rapidly, was sensitive to hydroxylamine, dependent on calcium, inhibited by lanthanum and stimulated by calmodulin. This was consistent with formation of an acyl-phosphate intermediate, indicating that maize CSCPA is a P-type ATPase, having a reaction mechanism similar to that of the erythrocyte CSCPA. A monoclonal antibody (EA6) was raised to maize CSCPA purified without PMSF; this antibody recognised intact maize CSCPA and inhibited calmodulin-stimulated ATPase activity in microsomal fractions. This antibody also bound to other polypeptides present in microsomal and purified fractions, permitting tentative identification of proteolysis products.

Thesis (M.S.)--University of Delaware, 2006. / Principal faculty advisor: James E. Swasey, Dept. of Plant & Soil Sciences. Includes bibliographical references.

Thesis (Ph. D.)--University of California, San Diego, 2001. / Vita. Accompanying videorecording (14 min. : sd., col. ; 1/2 in.) has title: Barbasco, la raíz de la discordia. Includes bibliographical references (leaves 248-266).

No description available.

No description available.

No description available.

No description available.

No description available.

Taxonomic confusion associated with Combretum Loefling, subgenus Combretum (Combretaceae) resulted in this investigation into the validity of sectional limits within the subgenus in southern Africa. Eight sections, together with their species and infraspecific taxa, totalling 29, are currently recognised in this region. Light and scanning electron microscopy on herbarium samples representing the taxa concerned were used to observe a final total of 171 selected characters. Data from individual specimens were collected numerically and processed to produce phenograms using Rohlf's NTSYS-pc program; also to produce descriptions in natural language format. A data processing program, TAXON, was specially designed and implemented to facilitate the desired processing and output. With the possible exceptions of Macrostigmatea and Ciliatipetala which require further investigation before certainty is reached, currently recognised sections were found to be valid and the limits between them acceptable. The main sources of confusion in this subgenus were found to lie in certain currently recognised species and their infraspecific taxa. These taxa were observed not to be distinct. The status of non-distinct species has been changed whenever clear evidence exists in favour of these changes. Other changes to species and infraspecific taxa have been recommended, but only to be implemented if supportive evidence is found after further investigations. Changes of status have been made in section Angustimarginata Engl. & Diels, where C. caffrum (Eckl. & Zeyh.) Kuntze and C. woodii Dummer have become synonyms of C. erythrophyllum (Burch.) Sond., and C. vendae Van Wyk has become a subspecies of C. erythrophyllum (Burch.) Sond., i.e. ssp. vendae (Van Wyk) Rodman comb. & stat. nov. (ined.); and in section Spathulipetala Engl. & Diels, where C. mkuzense Carr & Retief ,(section Macrostigmatea Engl. & Diels) has become a synonym of C. zeyheri Sond. C. collinum ssp. gazense (Swynn. & Bak.F.) Okafor, section Metallicum Fresen., has been changed to C. collinum ssp. coriaceum (Schinz) Rodman (ined.) in accordance with international botanical nomenclature. / Thesis (M.Sc.)-University of Durban-Westville, 1990.

This thesis describes investigations of the insecticidal compounds of three Sri Lankan plants, <i>Pleurostylia opposita</i> (Wall) Alston (Celastraceae), <i>Aegle marmelos</i> Correa (Rutaceae) and <i>Excoecaria agallocha</i> Linn. (Euphorbiaceae). After establishing the insecticidal activity of the extracts of three plants, separation of compounds was achieved by bio-assay directed chromatography, and the compounds were characterised by NMR especially 2D experiments, mass, UV and IR spectroscopy. Three new macrocyclic sesquiterpene polyol ester alkaloids 1, 2 and 3 containing a novel 6,7 ring skeleton have been identified from the petroleum ether-ethyl acetate extract of the stem bark of <i>Pleurstylia opposita</i>. They are homologues of known macrocyclic sesquiterpene alkaloids which contains a 6,6 ring system based on the ß-dihydroagarofuran core. The extra methylene has been shown by NMR to be in the 8 position of the 6,7 ring. Observation of insecticidal activity in the <i>Pleurostylia</i> genus is novel. The previously reported 20-hydroxylupane-3- one has also been identified from the active extract and shown to be noninsecticidal. Two new insecticidal compounds 6 and 7 have been identified from the petroleum ether-ethyl acetate extract of the stem bark of <i>Aegle marmelos</i>. They are shown to be protolimonoids, and are senecioate ester analogues of the known isovalerate esters of C-21-ß and C-21-α glabretal which were also isolated. Compounds 8 and 9 were also found to be insecticidal against mustard beetles and houseflies. Separation and characterisation of epimeric mixtures were first achieved for the di p-nitrobenzoate derivative. Previously recorded epoxyaurapten, marmesin, marmin and lupeol have been isolated from the active extract of <i>Aegle marmelos</i> and shown to be noninsecticidal. Five compounds 24-28 have been isolated from the ethyl acetate extract of the stem bark of <i>Excoecaria agallocha</i>. They all have the previously reported daphnane diterpenoid orthoester skeleton, and differ only in the orthoester alkyl side chain. Two of them 24 and 27 are novel. Insecticidal activity has not been recorded previously for extracts of <i>Excoecaria</i> species, nor for the daphnane orthoesters.