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dc.contributor.advisorKock, J. L. F.
dc.contributor.advisorSwart, C. W.
dc.contributor.advisorPohl, C. H.
dc.contributor.advisorVan Wyk, P. W. J.
dc.contributor.authorOlivier, Andries Petrus Stephanus
dc.date.accessioned2015-10-28T08:54:14Z
dc.date.available2015-10-28T08:54:14Z
dc.date.copyright2013-11
dc.date.issued2013-11
dc.date.submitted2013-11
dc.identifier.urihttp://hdl.handle.net/11660/1451
dc.description.abstractEnglish: Previous unpublished research by Kock and co-workers indicated that the antimalarial drug chloroquine (CQ) stimulates yeast sexual stages (biosensors). Consequently several indicator yeasts (Eremothecium ashbyi, Dipodascopsis uninucleata var. uninucelata, Lipomyces yamadae and Scheffersomyces stipitis) were exposed to concentration gradients of CQ in the Anti-mitochondrial Antifungal Assay (3A) system and their ascospore release mechanics were subjected to Auger architectomics. Auger architectomics is the study of the structure and atomic composition of cells by making use of Nano Scanning Auger Microscopy (NanoSAM) as well as other techniques (http://en.wikipedia.org/wiki/Auger_architectomics). Investigation of the ascospore release mechanics revealed that L. yamadae and S. stipitis were sequestrate (making use of passive ascospore release) while E. ashbyi and D. uninucleata made use of active ascospore release. The sensors of L. yamadae have smooth, spherical ascospores that are released by destruction of the sensor wall. The spherical sensors of S. stipitis each contain two brimmed (“hat”-shaped) ascospores that are released when the sensor wall breaks apart. The sensors of E. ashbyi are mostly intercalary in long chains with up to sixteen sickle-shaped ascospores in each ellipsoidal sensor. The V-shaped fins at the base of each ascospore of E. ashbyi are coated with 3-hydroxy (3-OH) oxylipins, making them hydrophobic. This facilitates the movement of ascospores by water flow. The tapered tips of the ascospores pierce through the sensor wall to allow release (http://vimeo.com/61521401). In D. Uninucleata, the inside surface of the sensors are lined with flexible sheaths, surrounding the ascospores inside the central channel. Inflation of the sheaths due to water uptake, generates turgor pressure that forces the ascospores out of the sensor. This is in sharp contrast to the morphologically similar yeast Dipodascus geniculatus, where the inflation of sheaths surrounding each individual ascospore is responsible for ascospore release. In all cases the sensors with ascospores were observed to have increased mitochondrial activity compared to surrounding cells. It was found with the 3A system that CQ is indeed a potent yeast fertility drug, having pro-fertility effects on all the yeast sensors used, including yeasts with decreased ability to sporulate due to preservation by sub-cultivation. Chloroquine caused increased formation of mature sensors of L. yamadae and S. stipitis, and increased the rate of ascospore release from the sensors of E. ashbyi and D. uninucleata. This data becomes even more compelling when considered that the S. stipitis strain used had lost the ability to sporulate prior to this study. An investigation of the relevant literature showed that the pro-fertility effects of CQ are highly conserved in the Eukarya, having similar effects on mammals (including humans) as well as the malaria causing parasite Plasmodium falciparum. This highlights the need to re-evaluate future and current CQ based treatment regimes.en_ZA
dc.description.abstractAfrikaans: Inligting van ongepubliseerde studies deur Kock en medewerkers het aangedui dat die malaria teenmiddel chloroquine (CQ), die seksuele fases (sensors) van gis stimuleer. Gevolglik is verskeie sensorgiste (Eremothecium ashbyi, Dipodascopsis uninucleata var. uninucleata, Lipomyces yamadae en Scheffersomyces stipitis) blootgestel aan konsentrasie gradiente van CQ in die Anti-mitokondriale, Antifungale Toets (AAT) sisteem, wat gekoppel is aan Auger argitektomika. Auger argitektomika is die studie van ‘n sel se struktuur en atomiese samestelling deur gebruik te maak van Nano Skandering Auger Mikroskopie (NanoSAM) en ander tegnieke. (http://en.wikipedia.org/wiki/Auger_architectomics). Ondersoek na die askospoorvrystellingsmeganika het uitgewys dat L. yamadae en S. stipitis gebruik maak van passiewe askospoorvrystelling, terwyl E. ashbyi en D. uninucleata gebruik maak van aktiewe askospoorvrystelling. Die sensors van L. yamadae besit gladde, sferiese askospore wat vrygestel word na afbreek van die sensorwand. Die sferiese sensors van S. stipitis huisves elk twee gerandte (“hoed”- vormige) askospore wat vrygestel word wanneer die sensorwand opbreek. Die sensors van E. ashbyi is meestal in kettings gerangskik met soveel as sestien sekelvormige askospore in elke ovaalvormige sensor. Die V-vormige vinne op die basis van elke askospoor is bedek met 3-hidroksie (3-OH) oksielipiene, wat die vinne hidrofobies maak en die beweging van die askospoor in stromende water bewerkstellig (http://vimeo.com/61521401). Die skerp punte van die askospore van E. ashbyi steek deur die sensorwand om die spore vry te stel. Die binneste oppervlak van die D. uninucleata sensorwand is uitgevoer met ‘n buigbare skede wat die askospore binne in ‘n sentrale kanaal omsluit. Die skedes swel op weens die 85 osmotiese opname van water, wat tot verhoogde turgordruk in die sensor lei wat askospoorvrystelling bewerkstellig. Dit is in skerp kontras met die morfologiese verwante gis Dipodascopsis geniculatus, waar die swelling van skedes rondom elke individuele askospoor verantwoordelik is vir askospoorvrystelling. In alle gevalle het die sensors en askospore verhoogde mitokondriale aktiwiteit getoon in vergelyking met die omliggende selle. Dit is met die 3A sisteem bevind dat CQ ‘n sterk gisfertiliteitsmiddel is, insluitend vir giste met gedempte vermoë om askospore te vorm weens die effek van subkultivering. Chloroquine het gelei tot verhoogde vorming van volwasse L. yamadae en S. stipitis sensors en het askospoorvrystelling gestimuleer in D. uninucleata en E. ashbyi. Die belang van dié inligting word meer duidelik wanneer in ag geneem word dat S. stipitis die vermoë verloor het om askospore te vorm voor die aanvang van die studie. Ondersoek van die relevante literatuur het bewys dat die pro-fertiliteitseffek van CQ hoogs gekonserveerd is in die Eukarya, met soortgelyke uitwerkings op soogdiere (insluitend mense) asook die malaria parasiet Plasmodium falciparum. Die inligting wat in die studie verkry is beklemtoon die behoefte om mediese behandeling wat op CQ gebaseer is, te herassesseer.af
dc.language.isoenen_ZA
dc.publisherUniversity of the Free Stateen_ZA
dc.subjectYeast sensorsen_ZA
dc.subjectYeast bio-assayen_ZA
dc.subjectFertility drugen_ZA
dc.subjectPro-mitochondrialen_ZA
dc.subjectChloroquineen_ZA
dc.subjectAuger-architectomicsen_ZA
dc.subjectAscospore releaseen_ZA
dc.subjectDissertation (M.Sc. (Microbial, Biochemical and Food Biotechnology))--University of the Free State, 2013en_ZA
dc.subjectFertility -- Effect of drugs onen_ZA
dc.subjectYeasten_ZA
dc.titleYeast sensors reveal chloroquine as yeast fertility drugen_ZA
dc.typeDissertationen_ZA
dc.rights.holderUniversity of the Free Stateen_ZA


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