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Marine bacteria as sources of antimycobacterial agents
Thesis (MSc)--Stellenbosch University, 2024.
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867613812270563328 |
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| access_status_str | Open Access |
| author | Thagulisi, Funanani |
| author2 | Tapfuma, Kudzanai Ian |
| author_browse | Tapfuma, Kudzanai Ian Thagulisi, Funanani |
| author_facet | Tapfuma, Kudzanai Ian Thagulisi, Funanani |
| author_sort | Thagulisi, Funanani |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description |
Thesis (MSc)--Stellenbosch University, 2024. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/131930 |
| institution | Stellenbosch University (South Africa) |
| last_indexed | 2026-06-10T12:42:05.565Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/131930 Marine bacteria as sources of antimycobacterial agents Thagulisi, Funanani Tapfuma, Kudzanai Ian Baatjies, Lucinda Mavumengwana, Vuyo Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Molecular Biology and Human Genetics. Marine bacteria -- Microbiology Marine natural products -- Therapeutic use Antitubercular agents Antibacterial agents Thesis (MSc)--Stellenbosch University, 2024. ENGLISH ABSTRACT: Tuberculosis (TB) is a contagious disease that mainly affects the lungs. Treating TB is complicated because the causative agent, Mycobacterium tuberculosis, is a type of bacterium that infects and kills cells of the immune system, while also developing resistance to many of the currently used TB drugs. A substantial portion of the global population suffering from TB is infected by mycobacterial strains that are resistant to the currently used first-line or second-line anti-TB drug. Therefore, to reduce the spread of TB, drug discovery studies are necessary to find new antimycobacterial compounds with novel mechanisms of action yet equally effective in treating TB. Marine bacteria-derived compounds have demonstrated significant potential in this field, presenting a compelling opportunity for further exploration and development of novel TB compounds. In this study, bacterial crude extracts derived from marine sediments collected along the Eastern and Western Coastal areas of the Cape Town, Western Cape beaches were investigated for antimycobacterial activity. This effort included screening their growth inhibitory effects on Mycobacterium smegmatis mc2155 infected THP-1 macrophage cells, identifying and characterizing the bacterial diversity of the mixed bacterial cultures associated with the bioactive bacterial crude extracts, and identifying potential compounds that may be responsible for the observed bioactivity. A total of 48 bacterial crude extract were derived from 17 marine sediments. Of the 48 bacterial extracts, five methanolic extracts showed strong antimycobacterial activity with minimum inhibitory concentration ranges of 62.5-31.25 and >2 μg/mL against Mycobacterium smegmatis mc2155 and Mycobacterium tuberculosis H37Rv, respectively. An untargeted metabolite profiling of the five bioactive bacterial crude extracts revealed the presence of metabolites previously reported for their antimicrobial activities in other studies. When screened against infected Mycobacterium smegmatis mc2155 THP-1 macrophage cells, the bacterial crude extract, CR_1, exhibited the lowest survival rate (27.17 ± 5.975% survival (p= 0.0468)) of Mycobacterium smegmatis mc2155 in THP-1 macrophage cell after 24 hrs of treatment. CR_1 bacterial crude extract exhibited the highest amount of early apoptosis activity of 16.83%, followed by GCR_1, PPB_1, PPB_2, and BB_1 with apoptotic percentages of 7.06%, 4.04%, 3.69%, and 3.31%, respectively. The bacterial crude extracts were tested at a concentration of 62.5 μg/mL after 24-hours treatment. The metagenomics analysis revealed a wide variety of bacteria, with the genus Halomonas being the predominant group in all bacterial crude extracts. Results from this study showed that marine sediments are a rich source for isolating microbes capable of producing novel compounds with potent antimycobacterial and immunomodulatory activity. AFRIKAANSE OPSOMMING: Tuberkulose (TB) is 'n aansteeklike siekte wat hoofsaaklik die longe beïnvloed. Diebehandeling van TB is ingewikkeld omdat die oorsaaklike agent, Mycobacterium tuberculosis, 'n soort bakterie is wat die selle van die immuunstelsel infekteer en doodmaak, terwyl dit ook weerstand teen baie van die huidige TB-middels ontwikkel. 'n Beduidende deel van die wêreldbevolking wat aan TB ly, is besmet met mykobakteriële stamme wat bestand is teen die huidige eerste- en tweede-lyn anti-TB-middels. Daarom, om die verspreiding van TB te verminder, is geneesmiddelontdekkingstudies noodsaaklik om nuwe antimykobakteriële verbindings met nuwe werkingsmeganismes te vind wat ewe effektief is in die behandeling van TB. Verbindings wat van mariene bakterieë af kom, het beduidende potensiaal in hierdie veld getoon, wat 'n aantreklike geleentheid bied vir verdere verkenning en ontwikkeling van nuwe TB-verbindings. In hierdie studie is bakteriële ruwe uittreksels afkomstig van mariene sediment wat langs die Oos- en Weskusareas van Kaapstad, Wes-Kaap-strande versamel is, ondersoek vir antimykobakteriële aktiwiteit. Hierdie poging het die toets van hulle groeihamperende effekte op Mycobacterium smegmatis mc2155 besmette THP-1 makrofage selle ingesluit, die identifisering en karakterisering van die bakteriële diversiteit van die gemengde bakteriële kulture wat met die bioaktiewe bakteriële ruwe uittreksels geassosieer word, en die identifisering van potensiële verbindings wat verantwoordelik mag wees vir die waargeneemde bioaktiewe eienskappe. 'n Totaal van 48 bakteriële ruwe uittreksels is afgelei van 17 mariene sedimenten. Van die 48 bakteriële uittreksels het vyf metanoliese uittreksels sterk antimykobakteriële aktiwiteit getoon met minimum inhiberingskonsentrasie reekse van 62.5-31.25 en >2 μg/mL teen Mycobacterium smegmatis mc2155 en Mycobacterium tuberculosis H37Rv, onderskeidelik. 'n Ongekykte metabolietprofielering van die vyf bioaktiewe bakteriële ruwe uittreksels het die teenwoordigheid van metaboliete wat vroeër vir hul antimikriese aktiwiteit in ander studies gerapporteer is, onthul. Toe getoets teen besmette Mycobacterium smegmatis mc2155 THP-1 makrofage selle, het die bakteriële ruwe uittreksel, CR_1, die laagste oorlewingsyfer (27.17 ± 5.975% oorlewing (p= 0.0468)) van Mycobacterium smegmatis mc2155 in THP-1 makrofage selle na 24 uur se behandeling vertoon. CR_1 bakteriële ruwe uittreksel het die hoogste hoeveelheid vroeë apoptose aktiwiteit van 16.83% getoon, gevolg deur GCR_1, PPB_1, PPB_2, en BB_1 met apoptotiese persentasies van 7.06%, 4.04%, 3.69%, en 3.31%, onderskeidelik. Die bakteriële ruwe uittreksels is getoets by 'n konsentrasie van 62.5 μg/mL na 24-ure behandeling. Die metagenomiese analise het 'n wye verskeidenheid bakterieë onthul, met die genus Halomonas as die oorheersende groep in alle bakteriële ruwe uittreksels. Resultate van hierdie studie het getoon dat mariene sediment 'n ryk bron is vir die isolering van mikrobes wat in staat is om nuwe verbindings met kragtig antimykobakteriële en immunomodulatoriese aktiwiteit te produseer. Masters 2025-04-29T09:21:13Z 2025-04-29T09:21:13Z 2024-12 Thesis https://scholar.sun.ac.za/handle/10019.1/131930 Stellenbosch University xvii, 131 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Marine bacteria -- Microbiology Marine natural products -- Therapeutic use Antitubercular agents Antibacterial agents Thagulisi, Funanani Marine bacteria as sources of antimycobacterial agents |
| title | Marine bacteria as sources of antimycobacterial agents |
| title_full | Marine bacteria as sources of antimycobacterial agents |
| title_fullStr | Marine bacteria as sources of antimycobacterial agents |
| title_full_unstemmed | Marine bacteria as sources of antimycobacterial agents |
| title_short | Marine bacteria as sources of antimycobacterial agents |
| title_sort | marine bacteria as sources of antimycobacterial agents |
| topic | Marine bacteria -- Microbiology Marine natural products -- Therapeutic use Antitubercular agents Antibacterial agents |
| url | https://scholar.sun.ac.za/handle/10019.1/131930 |
| work_keys_str_mv | AT thagulisifunanani marinebacteriaassourcesofantimycobacterialagents |