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Item BIOASSAY-GUIDED ISOLATION OF FURIN INHIBITORS FROM LEAF EXTRACT OF Momordica charantia L.(2022-09-18) Famutimi, Oladoyin Grace; Adewale, Isaac Olusanjo; Osiebe, Oghenesivwe; Aderogba, Mutalib AdeniranProprotein convertase-furin is involved in numerous physiological and pathogenic processes, such as viral propagation, bacterial toxin activation, cancer, and metastasis. Because of its involvement in these disease-related processes, the inhibition of this enzyme could be a promising drug target. The several existing synthetic inhibitors of furin are associated with side effects. Hence, we focused on natural sources, in particular, medicinal plant with antiviral capabilities. This study was designed to isolate the bioactive secondary metabolites present in Momordica charantia leaf extract and determine their potential bioactivity on furin. M. charantia leaves were air-dried, ground to fine powder and extracted using 80% (v/v) methanol. The methanolic extract was concentrated in vacuo at 40 oC and the crude extract obtained was partitioned successively with n-hexane (HEX), dichloromethane (DCM), ethyl acetate (EtOAc) and n-butanol (BuOH). A bioassay-guided screening of the crude extract and solvent fractions was carried out against the activity of recombinant human furin with the release of fluorescent 7-amino-4-methyl coumarin (AMC) liberated from the substrate, Pyroglutamic acid-Arg-Thr-Lys-Arg-methyl-coumaryl-7-amide, in a fluorimeter plate reader. Thereafter, the most potent fraction was subjected to chromatographic separation using thin layer (TLC) and column chromatographic techniques. The eluted fractions and subfractions were screened for bioactivity. The crude extract showed inhibition percentages of 51.9 and 100% at 7 and 12.5 ng/μl, respectively. The HEX fraction (7 ng/μl) exerted the highest inhibition (72%) on furin compared to other fractions while the BuOH fraction activated the enzyme by 1.5%. The chromatographed HEX fraction yielded seven (7) fractions with different physical properties. Five of these fractions gave single spot on TLC plate. Six fractions (MC I to VI) exhibited potent inhibition against furin with inhibition percentages ranging from 67 to 100% when 0.5 ng/μl of the inhibitor was used. Further fractionation of MC VI on preparative thin layer chromatography gave two sub fractions (A and B) which gave 50% inhibition, respectively. Overall, the presence of these potent inhibitors of furin in the leaf extract of M. charantia could provide a rationale for the ethnomedicinal use of the plant for viral infection in Nigerian folk medicine. Also, further investigations are underway for a better understanding and structural elucidation of the secondary metabolites responsible for the bioactivity observed on furin.Item The Future of Open Science: Unlocking Knowledge Together – Open Science Training(2023-10-31) Nyirongo, RevelationUbuntuNet Alliance under the AfricaConnect3 project invited 20 librarians to participate in a one-day Open Science training session a day before the UbuntuNet Connect 2023 Conference.Item Libraries In The Age Of Technocoloniality: Epistemic Alienation In African Scholarly Communications(2021-05-05) Mboa Nkoudou, Thomas HervéThis keynote was delivered during the Critical Approaches to Libraries Conference 2021Item Digital Surveillance and Digitally-disadvantaged Language Communities(2019-12-04) Zaugg, IsabelleThe issue of digital surveillance often falls outside urgent discussions regarding the need to build digital supports for under- resourced languages. While the benefits of these supports for digitally-disadvantaged language communities are clear, the reality is that standardized script use, standardized spelling, and NLP systems in particular increase a language community’s legibility for digital surveillance. As we build digital supports for Indigenous and minority language communities, we must consider how these tools might be used against them through digital surveillance, and how to combat these risks.Item Finetuning A Single-Blade Sonic Paper-Cutter As An Energy-Saving Sharpening Instrument(2022-02-11) Shava, Kudzai; Hlakudi, Carolline; Postema, Michiel; Carlson, CraigConstant usage and exposure to harsh environments results in a blade to become blunt. Two matching circuits were developed to improve the energy efficiency of an ultrasonic single-blade paper-cutting tool, whilst enhancing the sharpness of the blade. The unmatched ultrasonic knife had a measured magnitude of −0.3 dB and a resonance frequency of 251 kHz. The incorporation of a matching circuit significantly improved the magnitude indicating greater power transfer and consequently energy efficiency. The sharpening effect of ultrasound was qualitatively and quantitatively investigated, where both yielded a less tortuous cut under sonication in comparison to the unsonicated case. The addition of a matching circuit further improved the cutting efficiency. At an operating voltage of 10V peak , the cut made by the ultrasonic knife with a matching circuit was less tortuous than even an industrially cut edge, with a linearity of 61–63 % compared to 59 %, respectively.