Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Fluoroacetate metabolism of Dichapetalum Cymosum
Thesis (PhD (Plant Physiology))--University of Pretoria, 1991.
Saved in:
| Other Authors: | |
|---|---|
| Format: | Thesis |
| Language: | English |
| Published: |
University of Pretoria
2022
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613537210204160 |
|---|---|
| access_status_str | Open Access |
| author2 | Grobbelaar, N. |
| author_browse | Grobbelaar, N. |
| author_facet | Grobbelaar, N. |
| collection | Thesis |
| dc_rights_str_mv | © 2020 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Thesis (PhD (Plant Physiology))--University of Pretoria, 1991. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/85324 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:43.241Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2022 |
| publishDateRange | 2022 |
| publishDateSort | 2022 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/85324 Fluoroacetate metabolism of Dichapetalum Cymosum Grobbelaar, N. Meyer, Jacobus Johannes Marion UCTD Fluoroacetate metabolism Dichapetalum Cymosum Thesis (PhD (Plant Physiology))--University of Pretoria, 1991. A fast and sensitive method was developed for the determination of fluoroacetate in Dichapetalum cymosum using high-performance liquid chromatography. The highest concentrations of fluoroacetate were found in the immature seeds, flowers and young leaves of the plant. The young leaves are more toxic than the older leaves, probably because the rate of fluoroacetate degradation is higher in old leaves than in younger leaves. Foliarly applied fluoroacetate is also more readily accumulated by the young than by the older leaves of D. cymosum. Fluoroacetate can be taken up by the roots of D. cymosum and be transported to the leaves. Whether this happens to a significant extent under natural conditions is unknown. It was, however, demonstrated in this study that aseptically grown D. cymosum seedlings, as well as an aseptic callus culture of the plant, is capable of producing fluoroacetate. A pseudomonad was isolated from D. cymosum and identified as Pseudomonas cepacia. It was established that an isolate of this bacterium could grow in fluoroacetate enriched solutions without any reduction in growth rate. This bacterium is capable of defluorinating fluoroacetate and also of liberating CO2 from fluoroacetate. It seems as though the synthesis of N-methyl alanine and the occurrence of N-methyl serine in D. cymosum, is a result of the symbiosis between the plant and its endophyte. An aseptic callus culture of D. cymoswa is capable of degrading fluoroacetate albeit at a much lower rate than the leaves of the plant. By contaminating the callus with P. cepacia, isolated from the plant, the rate of CO2 release from fluoroacetate was increased about five fold. A D. cymosum crude mitochondrial enzyme extract can release CoASH from fluoroacetyl-CoA at a rate of 29.5 nmoles/min/mg protein, indicating the presence in the extract of an enzyme which is probably fluoroacetyl-CoA hydrolase. This enzyme could not use acetyl-CoA as a substrate. The presence of the fluoroacetyl-CoA hydrolase-like enzyme in D. cymosum together with the ability of the plant and its endophyte to degrade the fluoroacetate, helps to explain why D. cymosum is not poisoned by the high fluoroacetate concentrations which occur in the plant at times. Plant Science PhD (Plant Physiology) Unrestricted 2022-05-17T11:20:12Z 2022-05-17T11:20:12Z 2021/09/20 1991 Thesis * https://repository.up.ac.za/handle/2263/85324 en © 2020 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Fluoroacetate metabolism Dichapetalum Cymosum Fluoroacetate metabolism of Dichapetalum Cymosum |
| title | Fluoroacetate metabolism of Dichapetalum Cymosum |
| title_full | Fluoroacetate metabolism of Dichapetalum Cymosum |
| title_fullStr | Fluoroacetate metabolism of Dichapetalum Cymosum |
| title_full_unstemmed | Fluoroacetate metabolism of Dichapetalum Cymosum |
| title_short | Fluoroacetate metabolism of Dichapetalum Cymosum |
| title_sort | fluoroacetate metabolism of dichapetalum cymosum |
| topic | UCTD Fluoroacetate metabolism Dichapetalum Cymosum |
| url | https://repository.up.ac.za/handle/2263/85324 |