Thesis (M.Sc.) -- University of Adelaide, Dept. of Botany, 1979.

Thesis--Johns Hopkins University. / Repr.: Botanical gazette. July, 1912. Cover title.

Thesis (Ph. D.)--Columbia University, 1922. / Cover title. Curriculum vitae. "Reprinted from the American journal of physiology, vol. 60, no. 1, p. 1, March, 1922, Baltimore, Maryland." Bibliography: p. 45-47.

No description available.

Oligopeptide transport in rat small intestine has been studied in intact tissue, using the luminally and vascularly perfused isolated jejunum in situ technique, and a hydrolysis-resistant dipeptide (D-Phe-L-Gln). The data in this thesis can be divided into two main sections: (l) identification of the transporter proteins, and (2) short-term regulation of transport. The basolateral peptide transporter protein has not, to date, been identified. A candidate protein was identified from membrane vesicles by a photo affinity labelling technique using a dipeptide derivative ([4-azido-3,5-3H-D-Phe]-L-Ala), previously shown to be an efficient substrate for the basolateral transporter. The labelled candidate protein was successfully isolated by 2-DE, which revealed an apparent Mr of 112 ± 2 kDa and a pI of approximately 6.5. Initial sequence analysis, tryptic digestion followed by MALDI-TOF analysis and Q-TOF fragmentation of a tryptic peptide, produced a peptide fingerprint and a sequence tag of 9 amino acids, respectively, which, together, did not completely and conclusively match to any known protein sequence contained within databases, therefore suggesting that the 112 kDa protein may be novel. Short-term regulation of peptide transport was also investigated using the vascular perfusion method. An amino acid-sensing pathway was discovered, using L-Leucine as the regulator, involving protein kinase cacades leading to p70S6k activation and subsequent stimulation ofbasolateral membrane peptide transport. A major conclusion arising from the data was the distinction between PepTl and the basolateral transporter, i.e. the sequence data obtained from the candidate protein did not match to the PepTl sequence; in addition there appeared to be distinct mechanisms of regulatory control at the two membranes. Efficient delivery of peptidomimetic drugs when adminsitered by the oral route requires knowledge of short-term regulation of intestinal peptide transport, in addition to the sequence and structure of the basolateral transporter. This thesis provides essential information, which may eventually contribute to the unequivocal identification and sequencing of the intestinal basolateral peptide transporter, ultimately leading to the future development of compounds with high bioavailability.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1971. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

I have isolated and characterized a recessive mutation in the Forked (FKD) gene that results in the abnormal initiation of vascular bundles in the foliar organs, such that the apices of the vascular bundles initiate freely. Once initiated, the development of Fkd vascular bundles is like wild type, generating an open vascular pattern of similar complexity to the closed venation pattern of wild type. Despite the significant alteration in the vascular pattern, Fkd plants are morphologically indistinct from wild type. fkd mutants do not show altered sensitivity to the effects of auxin and show additive phenotypes with auxin response mutants, suggesting the FKD is part of a pathway acting independently of auxin. The similarity of the open vascular pattern of Fkd plants to that of ancestral vascular plants suggests that acquisition of this pathway may have been critical in the evolution of the closed vascular pattern. / x, 55 leaves : ill. ; 28 cm.

The development of leaf vascular patterns is a highly regulated process. The plant hormone auxin is critical for vascular patterning: auxin canalization is proposed to cause files of cells to accumulate higher auxin levels and develop into veins. Thus, the response of cells to auxin and transport of auxin are critical to establish proper cell fate. We have characterized a mutation in the Arabidopsis thaliana gene name AUTOBAHN (ABN). abn leaves produce leaves that proliferate disorganized, overlapping veins parallel to the midvein with no differentiation of higher order veins. abn leaves show no normal aspects of the secondary auxin response though double mutant analysis suggest that ABN functions independently of previously characterized auxin response pathways. Wild type plants grown on an influx inhibitor phenocopy abn suggesting that abn is defective in carrier-mediated auxin influx. / x, 69 leaves : ill. ; 28 cm.

The complex vasculature seen in the vascular plants provides a scaffolding of structural support and is responsible for the movement of water, minerals, photosynthate and some hormones. The auxin canalization model proposes that a positive feedback mechanism causes auxin-transporting cells to become vascular cells. We have isolated a leaf-patterning mutant, unhinged (unh), which shows a simplified leaf vascular pattern with more freely ending veins and fewer secondary veins. Expression of the ATHB8::GUS reporter construct indicates that the UNH gene acts prior to procambial patterning of the first presumptive secondary veins. Expression of the auxin responsive reporter gene DR5::GUS is reduced in unh leaves and roots, indicating that UNH may be involved in auxin signaling. Increasing the level of auxin in unh leaves through the addition of auxin transport inhibitors, low concentrations of 2,4-dichlorophenoxyacetic acid, and through introducing unh into mutants in which auxin transport is defective partially rescues the unh phenotype, supporting this hypothesis. The unh mutation maps to a 60kb region near the top of chromosome IV. No other leaf vascular mutant or auxinassociated mutant have been reported in this area, thus UNH represents a novel component of leaf vascularization and auxin signaling. / xi, 65 leaves : ill. (some col.) ; 29 cm.

No description available.