Research Articles (SAHSMI)http://hdl.handle.net/10566/21812024-03-28T16:05:38Z2024-03-28T16:05:38ZBioassay-guided fractionation leads to the detection of cholic acid generated by the rare thalassomonas sp.Schneider, Yannik K.-H.Pheiffer, FazlinHolst Hansen, EspenHammer Andersen, Jeanettehttp://hdl.handle.net/10566/83792023-02-09T00:01:49Z2023-01-01T00:00:00ZBioassay-guided fractionation leads to the detection of cholic acid generated by the rare thalassomonas sp.
Schneider, Yannik K.-H.; Pheiffer, Fazlin; Holst Hansen, Espen; Hammer Andersen, Jeanette
Bacterial symbionts of marine invertebrates are rich sources of novel, pharmaceutically
relevant natural products that could become leads in combatting multidrug-resistant pathogens
and treating disease. In this study, the bioactive potential of the marine invertebrate symbiont
Thalassomonas actiniarum was investigated. Bioactivity screening of the strain revealed Gram-positive
specific antibacterial activity as well as cytotoxic activity against a human melanoma cell line (A2058).
The dereplication of the active fraction using HPLC-MS led to the isolation and structural elucidation
of cholic acid and 3-oxo cholic acid. T. actiniarum is one of three type species belonging to the genus
Thalassomonas. The ability to generate cholic acid was assessed for all three species using thin-layer
chromatography and was confirmed by LC-MS. The re-sequencing of all three Thalassomonas type
species using long-read Oxford Nanopore Technology (ONT) and Illumina data produced complete
genomes, enabling the bioinformatic assessment of the ability of the strains to produce cholic acid.
Although a complete biosynthetic pathway for cholic acid synthesis in this genus could not be
determined based on sequence-based homology searches, the identification of putative penicillin or
homoserine lactone acylases in all three species suggests a mechanism for the hydrolysis of conjugated
bile acids present in the growth medium, resulting in the generation of cholic acid and 3-oxo cholic
acid. With little known currently about the bioactivities of this genus, this study serves as the
foundation for future investigations into their bioactive potential as well as the potential ecological
role of bile acid transformation, sterol modification and quorum quenching by Thalassomonas sp. in
the marine environment
2023-01-01T00:00:00ZIn vitro evaluation of the antiproliferative activity of Carpobrotus edulis on human neuroblastoma cellsEkpo, Okobi EkoEnogieru, Adaze BijouOmoruyi, Sylvester Ifeanyihttp://hdl.handle.net/10566/76022022-07-19T00:01:05Z2021-01-01T00:00:00ZIn vitro evaluation of the antiproliferative activity of Carpobrotus edulis on human neuroblastoma cells
Ekpo, Okobi Eko; Enogieru, Adaze Bijou; Omoruyi, Sylvester Ifeanyi
Neuroblastoma is a solid neuroendocrine tumour located outside the cranial cavity and contributes about 15% of
all cancer‑associated deaths in children. Treatment of neuroblastoma is quite challenging and involves the use of
chemotherapy, surgery and radiotherapy. Despite treatment strategies, systemic toxicity are setbacks to patient
well-being, hence the need for a new and affordable approach. Medicinal plants are of importance in the field of
drug discovery for cancer as some notable anti-cancer agents have been isolated from them. In the present study,
the anti-cancer activity of aqueous extract of Carpobrotus edulis (C. edulis), a ground-creeping edible medicinal
plant was investigated in SK-N-BE(2) and SH-SY5Y neuroblastoma cells. The effect of C. edulis on cell viability
and survival was determined using MTT (3-[4,5-dimethylthiazol-2-yl] 2,5 diphenyltetrazolium bromide) and
clonogenic assays respectively. Apoptosis was determined using a Caspase-9 assay kit and flow cytometry was
used to measure intracellular reactive oxygen species (ROS) and depolarization of mitochondrial membrane
potential. The results show that C. edulis inhibits cell viability (IC50 of 0.86 mg/ml and 1.45 mg/ml for SK-N-BE
(2) and SHSY5Y cells respectively) and colony formation in the neuroblastoma cells as well as induce apoptosis,
which is evidenced by an increase in caspase-9 activity in the cells. C. edulis also led to a loss of mitochondrial
membrane potential and increased production of ROS. Collectively, these results suggest that C. edulis induces
cell death via induction of mitochondrial-mediated apoptosis and accumulation of intracellular ROS, thus
providing a rationale for further investigations.
2021-01-01T00:00:00ZSutherlandia frutescens: The meeting of science and traditional knowledgeAboyade, OluwaseyiStyger, GustavGibson, DianaHughes, Gailhttp://hdl.handle.net/10566/34342018-02-28T09:13:47Z2013-01-01T00:00:00ZSutherlandia frutescens: The meeting of science and traditional knowledge
Aboyade, Oluwaseyi; Styger, Gustav; Gibson, Diana; Hughes, Gail
Sutherlandia frutescens (L.) R.Br. (syn. Lessertia frutescens (L.) Goldblatt and J.C. Manning) is an indigenous medicinal plant extensively used in South Africa to treat a variety of health conditions. It is a fairly widespread, drought-resistant plant that grows in the Western, Eastern, and Northern Cape provinces and some areas of KwaZulu-Natal, varying in its chemical and genetic makeup across these geographic areas.1 Sutherlandia is widely used as a traditional medicine. Extensive scientific studies are being carried out on the safety, quality, and the efficacy of this medicinal plant to validate the traditional claims, elucidate the bioactive constituents, and conduct clinical trials. This has resulted in a unique situation in South Africa’s history, where traditional knowledge and science intersect to provide insight into this popular plant. This photoessay attempts to illustrate the interlinkage of science with the indigenous knowledge of traditional healers, the local knowledge of people who care for the sick, product development, and innovation agenda of the country as it relates to this plant.
2013-01-01T00:00:00ZPhotosynthetic adaptation of two semi-arid species of Gethyllis (Kukumakranka) to drought-and-shade stressDaniels, C.W.Mabusela, Wilfred T.Marnewick, Jeanine L.Valentine, A.J.http://hdl.handle.net/10566/31822017-09-09T00:00:57Z2013-01-01T00:00:00ZPhotosynthetic adaptation of two semi-arid species of Gethyllis (Kukumakranka) to drought-and-shade stress
Daniels, C.W.; Mabusela, Wilfred T.; Marnewick, Jeanine L.; Valentine, A.J.
Gethyllis multifolia and Gethyllis villosa are winter-growing, summer-blooming, deciduous and
bulbous geophytes that grow naturally in the semi-arid ‘Succulent Karoo Biome’ of South Africa.
G. multifolia is threatened in its natural habitat and resides in the ‘Vulnerable’ category of the
‘Red Data List of Southern African Plants’. Previous investigations suggested that G. multifolia is
more sensitive to drought stress than G. villosa and that both species adopted certain
morphological changes in their leaves during shade stress. Current models indicate that this
biome is being exposed to increasingly drier conditions and shading from encroaching indigenous
plant species. In this study, the photosynthetic gas exchange responses of both species to drought
and shade stresses were investigated and the ‘Vulnerable’ conservation status of G. multifolia.
This investigation found that during drought stress G. villosa had a more enhanced
photosynthetic performance than
G. multifolia which appears not to be related to foliar adaptations such as specific leaf mass
(SLM), but to the G. villosa's leaves maintaining their stomatal conductance (Gs), photosynthetic
light compensation (LCP) and photon yields. Furthermore, during shade stress G. villosa also had
an improved photosynthetic performance by not altering its photosynthetic LCP during reduced light
conditions. It can be concluded that G. multifolia has a lower capacity than G. villosa to adapt
its photosynthetic apparatus to changing environments such as increasing drought and shaded
conditions. This may be a contributing factor to the threatened conservation status of G. multifolia.
2013-01-01T00:00:00Z