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2. SEASONAL VARIATIONS IN MICROMORPHOLOGY, ULTRASTRUCTURE, AND HISTOCHEMISTRY OF MANGO (MANGIFERA INDICA L.) LEAVES.

Author

MAHARAJ, A., NAIDOO, Y., DEWIR, Y. H., and MUJIB, A.

Subjects
MANGO, TRANSMISSION electron microscopy, SCANNING electron microscopy, ORGANELLES, LEAF anatomy
Abstract

Mangifera indica, a member of the Anacardiaceae family, is an important medicinal plant renowned for its wide range of biological activities. This study aims to examine M. indica from South Africa and describe its key micromorphological features related to foliar structures. Methods employed in this study include stereomicroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) for an in-depth analysis of foliar biology. Additionally, ImageJ software was used to measure the length and diameter values associated with different trichome types on M. indica leaves. The morphological evaluation using stereo- and SEM techniques revealed the presence of non-glandular trichomes with cuticular warts as well as glandular peltate trichomes. TEM micrographs confirmed the presence of numerous mitochondria, starch grains, plastoglobuli, and plastids, providing corroborating evidence of cellular organelles within these cells. Histophytochemical analysis of specific leaf sections further validated that alkaloids and phenolics are the major medicinal compounds obtained through extraction methods. The observations indicated no significant difference between summer and winter seasons concerning common morphology-related characteristics across all categories. The overall findings demonstrate that M. indica's usefulness for compound extractions remains consistent throughout the year due to its similar attributes between seasons. Consequently, continuous cultivation is established as crucial for developing sustainable approaches toward modern medicine. [ABSTRACT FROM AUTHOR]

Published
2024
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3. BIOACTIVE CONSTITUENTS AND POTENTIAL ANTIBACTERIAL ACTIVITY OF LAVENDER TREE (HETEROPYXIS NATALENSIS HARV.) LEAVES.

Author

MEER, S. D., NAIDOO, Y., DEWIR, Y. H., and MUJIB, A.

Subjects
TREATMENT effectiveness, METHICILLIN-resistant staphylococcus aureus, FATS & oils, METABOLITES, BACILLUS subtilis
Abstract

Heteropyxis natalensis is a South African medicinal tree that has been utilized by Venda and Zulu communities to treat several health ailments. The aim of this study was to elucidate the secondary metabolites in leaf extracts as well as to investigate the chemical profile and antibacterial efficacy of the methanolic leaf extract of H. natalensis. Qualitative phytochemical screening confirmed the presence of carbohydrates, alkaloids, phenolics, saponins, sterols, terpenes and fixed fats and oils in leaf extracts. Gas chromatographymass spectrometry identified 119 bioactive chemical compounds in the methanolic leaf extract of which 14 compounds had a peak area greater than 1%. In addition, methanolic extract was subjected to antibacterial screening using the well diffusion method. Heteropyxis natalensis exhibited antibacterial efficacy against 5 strains of pathogenic bacteria: Escherichia coli, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis. The results obtained in this study indicate the presence of naturally occurring bioactive compounds in H. natalensis leaves. [ABSTRACT FROM AUTHOR]

Published
2024
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4. GREEN SYNTHESIS OF SILVER NANOPARTICLES OF TAGETES MINUTA L. LEAVES AND ITS POTENTIAL ANTIBACTERIAL ACTIVITY.

Author

RIKISAHEDEW, J. J., NAIDOO, Y., and DEWIR, Y. H.

Subjects
SILVER nanoparticles, ANTIBACTERIAL agents, MARIGOLDS, FOURIER analysis, RAMAN scattering, ULTRAVIOLET-visible spectroscopy, TRANSMISSION electron microscopy
Abstract

The plant mediated synthesis of metallic nanoparticles is a fast-growing area of interest in the field of nanotechnology due to its eco-friendly approach. This study demonstrated the green synthesis of silver nanoparticles (AgNPs) using Tagetes minuta leaf extract. The AgNPs were characterised using UV-visible spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis and Fourier transform infrared (FTIR) spectroscopy. UV-visible spectrum of synthesised silver nanoparticles showed maximum peak at 442 nm. TEM revealed that the particles were spherical in shape and size ranging from 10 to 50 nm. The EDX spectrum confirmed the presence of silver metal. Preliminary antibacterial activity was determined using the agar well diffusion method, which showed growth inhibition against selected gram-positive and gram-negative bacteria. [ABSTRACT FROM AUTHOR]

Published
2024
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7. PHYTOCHEMICAL SCREENING AND POTENTIAL ANTIBACTERIAL ACTIVITY OF TAGESTES MINUTA L. LEAVES.

Author

RIKISAHEDEW, J. J., NAIDOO, Y., and DEWIR, Y. H.

Subjects
PHYTOCHEMICALS, ESCHERICHIA coli, ANTIBACTERIAL agents, GRAM-negative bacteria, BIOACTIVE compounds, ORGANIC solvents, SAPONINS
Abstract

Tagetes minuta is an important species in the traditional medicine due to its essential oil from leaves. In this study we report on the qualitative and quantitative phytochemical analyses of leaves extract using organic solvents. Qualitative analysis indicated the presence of alkaloids, sterols, saponins, terpenoids, phenols, and lipids in the leaves extract. Gas-chromatography mass-spectrometry (GC-MS) analysis revealed constituents with the highest percentage were 9-octadecen-1-ol (4.51%), β-sitosterol (6.07%), olean-12-en-3-one (7.47%), and 3-methyl-1-butanol (14.77%). Leaves extract showed inhibitory activity against selected gram-positive and gram-negative bacteria (P. aeruginosa, E. coli, S. aureus, MRSA, and B. subtilis). This study confirmed that the leaves of T. minuta contain bioactive compounds with pharmacological and biological properties that can be further explored. [ABSTRACT FROM AUTHOR]

Published
2023
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12. Omicron BA.4/BA.5 escape neutralizing immunity elicited by BA.1 infection

Author

Khan, K., Karim, F., Ganga, Y., Bernstein, M., Jule, Z., Reedoy, K., Cele, S., Lustig, G., Amoako, D., Wolter, N., Samsunder, N., Sivro, A., San, J., Giandhari, J., Tegally, H., Pillay, S., Naidoo, Y., Mazibuko, M., Miya, Y., Ngcobo, N., Manickchund, N., Magula, N., Karim, Q., von Gottberg, A., Karim, S., Hanekom, W., Gosnell, B., Team, C., Lessells, R., de Oliveira, T., Moosa, M., and Sigal, A.

Subjects
Multidisciplinary, Neutralization Tests, SARS-CoV-2, Spike Glycoprotein, Coronavirus, COVID-19, Humans, General Physics and Astronomy, General Chemistry, Antibodies, Viral, Antibodies, Neutralizing, General Biochemistry, Genetics and Molecular Biology
Abstract

SARS-CoV-2 Omicron (B.1.1.529) BA.4 and BA.5 sub-lineages, first detected in South Africa, have changes relative to Omicron BA.1 including substitutions in the spike receptor binding domain. Here we isolated live BA.4 and BA.5 viruses and measured BA.4/BA.5 neutralization elicited by BA.1 infection either in the absence or presence of previous vaccination as well as from vaccination without BA.1 infection. In BA.1-infected unvaccinated individuals, neutralization relative to BA.1 declines 7.6-fold for BA.4 and 7.5-fold for BA.5. In vaccinated individuals with subsequent BA.1 infection, neutralization relative to BA.1 decreases 3.2-fold for BA.4 and 2.6-fold for BA.5. The fold-drop versus ancestral virus neutralization in this group is 4.0-fold for BA.1, 12.9-fold for BA.4, and 10.3-fold for BA.5. In contrast, BA.4/BA.5 escape is similar to BA.1 in the absence of BA.1 elicited immunity: fold-drop relative to ancestral virus neutralization is 19.8-fold for BA.1, 19.6-fold for BA.4, and 20.9-fold for BA.5. These results show considerable escape of BA.4/BA.5 from BA.1 elicited immunity which is moderated with vaccination and may indicate that BA.4/BA.5 may have the strongest selective advantage in evading neutralization relative to BA.1 in unvaccinated, BA.1 infected individuals.

Published
2022

13. The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

Author

Tegally, H, San, JE, Cotten, M, Moir, M, Tegomoh, B, Mboowa, G, Martin, DP, Baxter, C, Lambisia, AW, Diallo, A, Amoako, DG, Diagne, MM, Sisay, A, Zekri, A-RN, Gueye, AS, Sangare, AK, Ouedraogo, A-S, Sow, A, Musa, AO, Sesay, AK, Abias, AG, Elzagheid, A, Lagare, A, Kemi, A-S, Abar, AE, Johnson, AA, Fowotade, A, Oluwapelumi, AO, Amuri, AA, Juru, A, Kandeil, A, Mostafa, A, Rebai, A, Sayed, A, Kazeem, A, Balde, A, Christoffels, A, Trotter, AJ, Campbell, A, Keita, AK, Kone, A, Bouzid, A, Souissi, A, Agweyu, A, Naguib, A, Gutierrez, A, Nkeshimana, A, Page, AJ, Yadouleton, A, Vinze, A, Happi, AN, Chouikha, A, Iranzadeh, A, Maharaj, A, Batchi-Bouyou, AL, Ismail, A, Sylverken, AA, Goba, A, Femi, A, Sijuwola, AE, Marycelin, B, Salako, BL, Oderinde, BS, Bolajoko, B, Diarra, B, Herring, BL, Tsofa, B, Lekana-Douki, B, Mvula, B, Njanpop-Lafourcade, B-M, Marondera, BT, Khaireh, BA, Kouriba, B, Adu, B, Pool, B, McInnis, B, Brook, C, Williamson, C, Nduwimana, C, Anscombe, C, Pratt, CB, Scheepers, C, Akoua-Koffi, CG, Agoti, CN, Mapanguy, CM, Loucoubar, C, Onwuamah, CK, Ihekweazu, C, Malaka, CN, Peyrefitte, C, Grace, C, Omoruyi, CE, Rafai, CD, Morang'a, CM, Erameh, C, Lule, DB, Bridges, DJ, Mukadi-Bamuleka, D, Park, D, Rasmussen, DA, Baker, D, Nokes, DJ, Ssemwanga, D, Tshiabuila, D, Amuzu, DSY, Goedhals, D, Grant, DS, Omuoyo, DO, Maruapula, D, Wanjohi, DW, Foster-Nyarko, E, Lusamaki, EK, Simulundu, E, Ong'era, EM, Ngabana, EN, Abworo, EO, Otieno, E, Shumba, E, Barasa, E, Ahmed, EB, Ahmed, EA, Lokilo, E, Mukantwari, E, Philomena, E, Belarbi, E, Simon-Loriere, E, Anoh, EA, Manuel, E, Leendertz, F, Taweh, FM, Wasfi, F, Abdelmoula, F, Takawira, FT, Derrar, F, Ajogbasile, F, Treurnicht, F, Onikepe, F, Ntoumi, F, Muyembe, FM, Ragomzingba, FEZ, Dratibi, FA, Iyanu, F-A, Mbunsu, GK, Thilliez, G, Kay, GL, Akpede, GO, van Zyl, GU, Awandare, GA, Kpeli, GS, Schubert, G, Maphalala, GP, Ranaivoson, HC, Omunakwe, HE, Onywera, H, Abe, H, Karray, H, Nansumba, H, Triki, H, Kadjo, HAA, Elgahzaly, H, Gumbo, H, Mathieu, H, Kavunga-Membo, H, Smeti, I, Olawoye, IB, Adetifa, IMO, Odia, I, Ben Boubaker, IB, Mohammad, IA, Ssewanyana, I, Wurie, I, Konstantinus, IS, Halatoko, JWA, Ayei, J, Sonoo, J, Makangara, J-CC, Tamfum, J-JM, Heraud, J-M, Shaffer, JG, Giandhari, J, Musyoki, J, Nkurunziza, J, Uwanibe, JN, Bhiman, JN, Yasuda, J, Morais, J, Kiconco, J, Sandi, JD, Huddleston, J, Odoom, JK, Morobe, JM, Gyapong, JO, Kayiwa, JT, Okolie, JC, Xavier, JS, Gyamfi, J, Wamala, JF, Bonney, JHK, Nyandwi, J, Everatt, J, Nakaseegu, J, Ngoi, JM, Namulondo, J, Oguzie, JU, Andeko, JC, Lutwama, JJ, Mogga, JJH, O'Grady, J, Siddle, KJ, Victoir, K, Adeyemi, KT, Tumedi, KA, Carvalho, KS, Mohammed, KS, Dellagi, K, Musonda, KG, Duedu, KO, Fki-Berrajah, L, Singh, L, Kepler, LM, Biscornet, L, Martins, LDO, Chabuka, L, Olubayo, L, Ojok, LD, Deng, LL, Ochola-Oyier, L, Tyers, L, Mine, M, Ramuth, M, Mastouri, M, ElHefnawi, M, Mbanne, M, Matsheka, M, Kebabonye, M, Diop, M, Momoh, M, Lima Mendonca, MDL, Venter, M, Paye, MF, Faye, M, Nyaga, MM, Mareka, M, Damaris, M-M, Mburu, MW, Mpina, MG, Owusu, M, Wiley, MR, Tatfeng, MY, Ayekaba, MO, Abouelhoda, M, Beloufa, MA, Seadawy, MG, Khalifa, MK, Matobo, MM, Kane, M, Salou, M, Mbulawa, MB, Mwenda, M, Allam, M, Phan, MVT, Abid, N, Rujeni, N, Abuzaid, N, Ismael, N, Elguindy, N, Top, NM, Dia, N, Mabunda, N, Hsiao, N-Y, Silochi, NB, Francisco, NM, Saasa, N, Bbosa, N, Murunga, N, Gumede, N, Wolter, N, Sitharam, N, Ndodo, N, Ajayi, NA, Tordo, N, Mbhele, N, Razanajatovo, NH, Iguosadolo, N, Mba, N, Kingsley, OC, Sylvanus, O, Femi, O, Adewumi, OM, Testimony, O, Ogunsanya, OA, Fakayode, O, Ogah, OE, Oludayo, O-E, Faye, O, Smith-Lawrence, P, Ondoa, P, Combe, P, Nabisubi, P, Semanda, P, Oluniyi, PE, Arnaldo, P, Quashie, PK, Okokhere, PO, Bejon, P, Dussart, P, Bester, PA, Mbala, PK, Kaleebu, P, Abechi, P, El-Shesheny, R, Joseph, R, Aziz, RK, Essomba, RG, Ayivor-Djanie, R, Njouom, R, Phillips, RO, Gorman, R, Kingsley, RA, Neto Rodrigues, RMDESA, Audu, RA, Carr, RAA, Gargouri, S, Masmoudi, S, Bootsma, S, Sankhe, S, Mohamed, SI, Femi, S, Mhalla, S, Hosch, S, Kassim, SK, Metha, S, Trabelsi, S, Agwa, SH, Mwangi, SW, Doumbia, S, Makiala-Mandanda, S, Aryeetey, S, Ahmed, SS, Ahmed, SM, Elhamoumi, S, Moyo, S, Lutucuta, S, Gaseitsiwe, S, Jalloh, S, Andriamandimby, SF, Oguntope, S, Grayo, S, Lekana-Douki, S, Prosolek, S, Ouangraoua, S, van Wyk, S, Schaffner, SF, Kanyerezi, S, Ahuka-Mundeke, S, Rudder, S, Pillay, S, Nabadda, S, Behillil, S, Budiaki, SL, van der Werf, S, Mashe, T, Mohale, T, Le-Viet, T, Velavan, TP, Schindler, T, Maponga, TG, Bedford, T, Anyaneji, UJ, Chinedu, U, Ramphal, U, George, UE, Enouf, V, Nene, V, Gorova, V, Roshdy, WH, Karim, WA, Ampofo, WK, Preiser, W, Choga, WT, Ahmed, YA, Ramphal, Y, Bediako, Y, Naidoo, Y, Butera, Y, de Laurent, ZR, Ouma, AEO, von Gottberg, A, Githinji, G, Moeti, M, Tomori, O, Sabeti, PC, Sall, AA, Oyola, SO, Tebeje, YK, Tessema, SK, de Oliveira, T, Happi, C, Lessells, R, Nkengasong, J, Wilkinson, E, Tegally, H, San, JE, Cotten, M, Moir, M, Tegomoh, B, Mboowa, G, Martin, DP, Baxter, C, Lambisia, AW, Diallo, A, Amoako, DG, Diagne, MM, Sisay, A, Zekri, A-RN, Gueye, AS, Sangare, AK, Ouedraogo, A-S, Sow, A, Musa, AO, Sesay, AK, Abias, AG, Elzagheid, A, Lagare, A, Kemi, A-S, Abar, AE, Johnson, AA, Fowotade, A, Oluwapelumi, AO, Amuri, AA, Juru, A, Kandeil, A, Mostafa, A, Rebai, A, Sayed, A, Kazeem, A, Balde, A, Christoffels, A, Trotter, AJ, Campbell, A, Keita, AK, Kone, A, Bouzid, A, Souissi, A, Agweyu, A, Naguib, A, Gutierrez, A, Nkeshimana, A, Page, AJ, Yadouleton, A, Vinze, A, Happi, AN, Chouikha, A, Iranzadeh, A, Maharaj, A, Batchi-Bouyou, AL, Ismail, A, Sylverken, AA, Goba, A, Femi, A, Sijuwola, AE, Marycelin, B, Salako, BL, Oderinde, BS, Bolajoko, B, Diarra, B, Herring, BL, Tsofa, B, Lekana-Douki, B, Mvula, B, Njanpop-Lafourcade, B-M, Marondera, BT, Khaireh, BA, Kouriba, B, Adu, B, Pool, B, McInnis, B, Brook, C, Williamson, C, Nduwimana, C, Anscombe, C, Pratt, CB, Scheepers, C, Akoua-Koffi, CG, Agoti, CN, Mapanguy, CM, Loucoubar, C, Onwuamah, CK, Ihekweazu, C, Malaka, CN, Peyrefitte, C, Grace, C, Omoruyi, CE, Rafai, CD, Morang'a, CM, Erameh, C, Lule, DB, Bridges, DJ, Mukadi-Bamuleka, D, Park, D, Rasmussen, DA, Baker, D, Nokes, DJ, Ssemwanga, D, Tshiabuila, D, Amuzu, DSY, Goedhals, D, Grant, DS, Omuoyo, DO, Maruapula, D, Wanjohi, DW, Foster-Nyarko, E, Lusamaki, EK, Simulundu, E, Ong'era, EM, Ngabana, EN, Abworo, EO, Otieno, E, Shumba, E, Barasa, E, Ahmed, EB, Ahmed, EA, Lokilo, E, Mukantwari, E, Philomena, E, Belarbi, E, Simon-Loriere, E, Anoh, EA, Manuel, E, Leendertz, F, Taweh, FM, Wasfi, F, Abdelmoula, F, Takawira, FT, Derrar, F, Ajogbasile, F, Treurnicht, F, Onikepe, F, Ntoumi, F, Muyembe, FM, Ragomzingba, FEZ, Dratibi, FA, Iyanu, F-A, Mbunsu, GK, Thilliez, G, Kay, GL, Akpede, GO, van Zyl, GU, Awandare, GA, Kpeli, GS, Schubert, G, Maphalala, GP, Ranaivoson, HC, Omunakwe, HE, Onywera, H, Abe, H, Karray, H, Nansumba, H, Triki, H, Kadjo, HAA, Elgahzaly, H, Gumbo, H, Mathieu, H, Kavunga-Membo, H, Smeti, I, Olawoye, IB, Adetifa, IMO, Odia, I, Ben Boubaker, IB, Mohammad, IA, Ssewanyana, I, Wurie, I, Konstantinus, IS, Halatoko, JWA, Ayei, J, Sonoo, J, Makangara, J-CC, Tamfum, J-JM, Heraud, J-M, Shaffer, JG, Giandhari, J, Musyoki, J, Nkurunziza, J, Uwanibe, JN, Bhiman, JN, Yasuda, J, Morais, J, Kiconco, J, Sandi, JD, Huddleston, J, Odoom, JK, Morobe, JM, Gyapong, JO, Kayiwa, JT, Okolie, JC, Xavier, JS, Gyamfi, J, Wamala, JF, Bonney, JHK, Nyandwi, J, Everatt, J, Nakaseegu, J, Ngoi, JM, Namulondo, J, Oguzie, JU, Andeko, JC, Lutwama, JJ, Mogga, JJH, O'Grady, J, Siddle, KJ, Victoir, K, Adeyemi, KT, Tumedi, KA, Carvalho, KS, Mohammed, KS, Dellagi, K, Musonda, KG, Duedu, KO, Fki-Berrajah, L, Singh, L, Kepler, LM, Biscornet, L, Martins, LDO, Chabuka, L, Olubayo, L, Ojok, LD, Deng, LL, Ochola-Oyier, L, Tyers, L, Mine, M, Ramuth, M, Mastouri, M, ElHefnawi, M, Mbanne, M, Matsheka, M, Kebabonye, M, Diop, M, Momoh, M, Lima Mendonca, MDL, Venter, M, Paye, MF, Faye, M, Nyaga, MM, Mareka, M, Damaris, M-M, Mburu, MW, Mpina, MG, Owusu, M, Wiley, MR, Tatfeng, MY, Ayekaba, MO, Abouelhoda, M, Beloufa, MA, Seadawy, MG, Khalifa, MK, Matobo, MM, Kane, M, Salou, M, Mbulawa, MB, Mwenda, M, Allam, M, Phan, MVT, Abid, N, Rujeni, N, Abuzaid, N, Ismael, N, Elguindy, N, Top, NM, Dia, N, Mabunda, N, Hsiao, N-Y, Silochi, NB, Francisco, NM, Saasa, N, Bbosa, N, Murunga, N, Gumede, N, Wolter, N, Sitharam, N, Ndodo, N, Ajayi, NA, Tordo, N, Mbhele, N, Razanajatovo, NH, Iguosadolo, N, Mba, N, Kingsley, OC, Sylvanus, O, Femi, O, Adewumi, OM, Testimony, O, Ogunsanya, OA, Fakayode, O, Ogah, OE, Oludayo, O-E, Faye, O, Smith-Lawrence, P, Ondoa, P, Combe, P, Nabisubi, P, Semanda, P, Oluniyi, PE, Arnaldo, P, Quashie, PK, Okokhere, PO, Bejon, P, Dussart, P, Bester, PA, Mbala, PK, Kaleebu, P, Abechi, P, El-Shesheny, R, Joseph, R, Aziz, RK, Essomba, RG, Ayivor-Djanie, R, Njouom, R, Phillips, RO, Gorman, R, Kingsley, RA, Neto Rodrigues, RMDESA, Audu, RA, Carr, RAA, Gargouri, S, Masmoudi, S, Bootsma, S, Sankhe, S, Mohamed, SI, Femi, S, Mhalla, S, Hosch, S, Kassim, SK, Metha, S, Trabelsi, S, Agwa, SH, Mwangi, SW, Doumbia, S, Makiala-Mandanda, S, Aryeetey, S, Ahmed, SS, Ahmed, SM, Elhamoumi, S, Moyo, S, Lutucuta, S, Gaseitsiwe, S, Jalloh, S, Andriamandimby, SF, Oguntope, S, Grayo, S, Lekana-Douki, S, Prosolek, S, Ouangraoua, S, van Wyk, S, Schaffner, SF, Kanyerezi, S, Ahuka-Mundeke, S, Rudder, S, Pillay, S, Nabadda, S, Behillil, S, Budiaki, SL, van der Werf, S, Mashe, T, Mohale, T, Le-Viet, T, Velavan, TP, Schindler, T, Maponga, TG, Bedford, T, Anyaneji, UJ, Chinedu, U, Ramphal, U, George, UE, Enouf, V, Nene, V, Gorova, V, Roshdy, WH, Karim, WA, Ampofo, WK, Preiser, W, Choga, WT, Ahmed, YA, Ramphal, Y, Bediako, Y, Naidoo, Y, Butera, Y, de Laurent, ZR, Ouma, AEO, von Gottberg, A, Githinji, G, Moeti, M, Tomori, O, Sabeti, PC, Sall, AA, Oyola, SO, Tebeje, YK, Tessema, SK, de Oliveira, T, Happi, C, Lessells, R, Nkengasong, J, and Wilkinson, E

Abstract

Investment in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing in Africa over the past year has led to a major increase in the number of sequences that have been generated and used to track the pandemic on the continent, a number that now exceeds 100,000 genomes. Our results show an increase in the number of African countries that are able to sequence domestically and highlight that local sequencing enables faster turnaround times and more-regular routine surveillance. Despite limitations of low testing proportions, findings from this genomic surveillance study underscore the heterogeneous nature of the pandemic and illuminate the distinct dispersal dynamics of variants of concern-particularly Alpha, Beta, Delta, and Omicron-on the continent. Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve while the continent faces many emerging and reemerging infectious disease threats. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century.

Published
2022

14. T cell responses to SARS-1 CoV-2 spike cross-recognize Omicron

Author

Keeton, R, Tincho, MB, Ngomti, A, Baguma, R, Benede, N, Suzuki, A, Khan, K, Madzorerera, SV, Moyo-Gwete, T, Mennen, M, SKelem, S, Adriaanse, M, Muthithu, D, Aremu, O, Stek, C, Du Bruyn, E, Van Der Mescht, MA, De Beer, Z, De Villiers, TR, Bodenstein, A, Van der Berg, G, Mendes, A, Strydom, A, Venter, M, Giandhari, J, Naidoo, Y, Pillay, S, Tegally, H, Grifoni, A, Weiskopf, D, Sette, A, Wilkinson, RJ, De Oliveira, T, Bekker, L-G, Gray, G, Ueckermann, V, Rossouw, T, Boswell, MT, Bihman, F, Moore, PL, Ntusi, NN, Burgers, WA, Riou, C, and Wellcome Trust

Subjects
Multidisciplinary Sciences, Science & Technology, General Science & Technology, Science & Technology - Other Topics
Abstract

The SARS-CoV-2 Omicron variant has multiple Spike (S) protein mutations1,2 that contribute to escape from antibody neutralization3–6 and reduce vaccine protection from infection7,8. The extent to which other components of the adaptive response such as T cells may still target Omicron and contribute to protection from severe outcomes is unknown. We assessed the ability of T cells to react with Omicron spike in participants who were vaccinated with Ad26.CoV2.S, BNT162b2, or unvaccinated convalescent COVID-19 patients (n=70). We found that 70-80% of the CD4+ and CD8+ T cell response to spike was maintained across study groups. Moreover, the magnitude of Omicron cross-reactive T cells was similar to Beta and Delta variants, despite Omicron harboring considerably more mutations. In Omicron-infected hospitalized patients (n=19), there were comparable T cell responses to ancestral spike, nucleocapsid and membrane proteins to those patients hospitalized in previous waves dominated by the ancestral, Beta or Delta variants (n=49). Thus, despite Omicron’s extensive mutations and reduced susceptibility to neutralizing antibodies, the majority of T cell responses, induced by vaccination or infection, cross-recognize the variant. It remains to be determined whether well-preserved T cell immunity to Omicron contributes to protection from severe COVID-19, and is linked to early clinical observations from South Africa and elsewhere9–12.

Published
2022

17. The overlap between income poverty and material deprivation: Sensitivity evidence for Australia

Author

Saunders, P, Naidoo, Y, Saunders, P, and Naidoo, Y

Abstract

Many studies have noted the low overlap between income poverty and material deprivation when the latter is derived using the consensual approach that builds on the work of Townsend. However, few have examined the contributing factors and even fewer have assessed the sensitivity of the overlap to different approaches and adjustments. This paper uses Australian data to examine the impact on the overlap of data adjustments and three substantive factors: short-run income fluctuations, housing costs and net wealth. The analysis shows that accounting for two of these factors leads to a marked increase in the overlap between poverty and deprivation.

Published
2020

26. Child Deprivation in Australia: A Child-focused Approach

Author

Naidoo, Y and Naidoo, Y

Abstract

Income-based studies of child poverty treat children and young people as effectively invisible and determine the poverty status of families or households on the basis of information that is provided by, and is primarily about, adults. In contrast, the consensual deprivation approach provides a way of developing measures that reflect the views of children about what constitutes poverty and can be applied to data that children themselves provide. This paper extends earlier Australian studies of adult deprivation by applying a similar approach to children aged 11-17 attending a NSW government high schools. Focus groups were conducted with children to help identify items regarded as essential for all children and the results informed the development of a survey that was completed by over 2,600 students. The survey asked about 24 items, 18 of which were retained after statistical testing and these items form the basis of the deprivation analysis. The findings indicate that a substantial portion of survey respondents experience either or both of material deprivation and social exclusion. A new Child Deprivation Index (CDI) is developed and used to compare the circumstances of different groups, highlighting some of the factors that are associated with higher levels of deprivation and providing some initial pointers to possible underlying causes.

Published
2019

27. Comparing the Implications of Expanded Income-Based Measures of Living Standards with an Application to Older Australians

Author

Naidoo, Y and Naidoo, Y

Abstract

The standard of living of older people is a critical policy matter, given Australia's ageing population. Conventional living standard assessments continue to rely on disposable income as a defining indicator, despite it not encompassing the full range of potential consumption possibilities that affect an individual's economic living standard. This article proposes a series of three economic resource metrics that sequentially append the disposable income metric with the value of non-cash benefits and services arising from the receipt of public goods and/or services from home ownership in the form of a 'full' income metric, and then the inclusion of wealth in the form of two derived 'potential consumption' metrics. Using data from the Household, Income and Labour Dynamics in Australia Survey, the findings demonstrate that augmenting disposable income with income streams from non-cash services and annuitised wealth substantially improves the relative economic position of older Australians. It also highlights the heterogeneity in economic living standard outcomes for different demographic sub-groups of older people that would otherwise be drawn using a disposable income analytic lens. The article argues that an expanded economic resource perspective is necessary for informing ageing and social policy.

Published
2019

28. Material Deprivation and Social Exclusion Among Young Australians: A child-focused approach

Author

Saunders, P, Bedford, M, Brown, J, Naidoo, Y, and Adamson, E

Abstract

This report is the first of its kind to apply the deprivation approach to examine deprivation among young Australians using information provided by young people themselves. It builds on earlier projects that developed and applied the approach used here to adults. Like many research projects of its kind, it has involved pulling together input from many sources over a sustained period, each of which was necessary to produce the final product.

Published
2018
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29. A survey of the quality of clinical learning environments of clinical placement settings as perceived by students from a provincial nursing college

Author

Naidoo, Y., Van der Walt, S.J.C., Prof, and 13275429 - Van der Walt, Sara Janetta Christina (Supervisor)

Subjects
clinical supervision, quality, registered nurse, clinical facilitator, education, Clinical learning environment, nursing student
Abstract

MCur (Health Science Education), North-West University, Potchefstroom Campus This study investigated the quality of the clinical learning environments in the medical and surgical units of clinical placements used by a provincial college of nursing for student nurse training in South Africa. The purpose of the study was to describe the quality of the clinical learning environment of placement settings, as experienced by final year students from a provincial nursing college. The researcher used a quantitative, descriptive, cross-sectional design. Purposive sampling was used to recruit research participants. Participants were final year undergraduate students of the Provincial College of Nursing. Informed, written consent was obtained. Ethical approval was obtained from the relevant authorities and the ethical committee of the North West University. Data was collected by using an internationally validated Clinical Learning Environment, Supervision and Nurse Teacher Instrument (Saarikoski & Leino-Kilpi, 2002:259-267; Saarikoski et al., 2008:1233-1237). The quantitative data showed that students are relatively satisfied with the quality of the clinical learning environment of their placement settings, the supervision they received and the role the nurse educator played in the clinical setting. The results showed that a little less than two thirds of students are satisfied with their clinical learning environment and just a little over half of students were satisfied with the supervision they received. However, the pedagogical atmosphere received the lowest evaluation. Interestingly, the most significant factors in the clinical learning environment, supervision and nurse teacher evaluation were the philosophical grounding of nursing care in the ward and the nurse educator enabling the integration of theory and practice. More support and commitment is also needed from the operational manager who is the main driver of the vehicle which is the clinical learning environment and who steers clinical teaching and learning forward. There was a significant positive correlation between philosophical grounding of nursing care in the ward and supervisory relationship. The most common method of supervision was group supervision. Even though there was mutual interaction in the supervisory relationship, there is a need for staff to provide students with constructive feedback on their professional performance in order for them to improve on the areas identified in the clinical learning environment and thus improve the quality of patient care. There is a need for the nurse teachers to be more visible in the clinical learning environment in order to provide additional support. Provision of a learner centred environment by nurse teachers and engagement of students as equal partners in the learning environment will enhance learning. The open-ended questions revealed there were many challenges in the clinical learning environment. Thus, there is plenty of room for improvement in all aspects of the clinical learning environment by all stakeholders to promote quality clinical learning, quality of care and improved patient outcomes. There is also a need for a quality assurance program in nursing education to constantly monitor and evaluate the clinical learning environment in order to maintain high standards and quality clinical learning. In conclusion, participants rated the quality of the clinical learning environment where they were placed for their medical and surgical nursing experience relatively low. Although there is a discrepancy between the qualitative rating of the quality of the clinical learning environments of these settings and the quantitative scoring thereof using the CLES-T instrument, both assessments are necessary to get the full picture. Using this approach will assist nurse educators to continuously assess the quality of the clinical learning environment of the settings where students are placed as to intervene when it becomes clear that a setting no longer complies to the requirements for effective clinical learning. Masters

Published
2018

36. Chronic rhinosinusitis: Potential role of microbial dysbiosis and recommendations for sampling sites

Author

Copeland, E, Leonard, K, Carney, R, Kong, J, Forer, M, Naidoo, Y, Oliver, BGG, Seymour, JR, Woodcock, S, Burke, CM, Stow, NW, Copeland, E, Leonard, K, Carney, R, Kong, J, Forer, M, Naidoo, Y, Oliver, BGG, Seymour, JR, Woodcock, S, Burke, CM, and Stow, NW

Abstract

© 2018 Copeland, Leonard, Carney, Kong, Forer, Naidoo, Oliver, Seymour, Woodcock, Burke and Stow. Chronic rhinosinusitis (CRS) is an inflammatory condition that affects up to 12% of the human population in developed countries. Previous studies examining the potential role of the sinus bacterial microbiota within CRS infections have found inconsistent results, possibly because of inconsistencies in sampling strategies. The aim of this study was to determine whether the sinus microbiome is altered in CRS and additionally if the middle meatus is a suitable representative site for sampling the sinus microbiome. Swab samples were collected from 12 healthy controls and 21 CRS patients, including all eight sinuses for CRS patients and between one and five sinuses for control subjects. The left and right middle meatus and nostril swabs were also collected. Significant differences in the sinus microbiomes between CRS and control samples were revealed using high-throughput 16S rRNA gene sequencing. The genus Escherichia was over-represented in CRS sinuses, and associations between control patients and Corynebacterium and Dolosigranulum were also identified. Comparisons of the middle meatuses between groups did not reflect these differences, and the abundance of the genus Escherichia was significantly lower at this location. Additionally, intra-patient variation was lower between sinuses than between sinus and middle meatus, which together with the above results suggests that the middle meatus is not an effective representative sampling site.

Published
2018

37. The secretory scales of Combretum erythrophyllum (Combretaceae): Micromorphology, ultrastructure and histochemistry.

Author

Bantho, S., Naidoo, Y., and Dewir, Y.H.

Subjects
*METABOLITES, *COMBRETACEAE, *PHENOLS, *TRICHOMES, *HEALERS, *ULTRASTRUCTURE (Biology)
Abstract

• Peltate scales and non-glandular trichomes from the leaves and stems of Combretum erythrophyllum , were observed and micro-analysed using various microscopy techniques. • The granulocrine pathway was identified as a possible mode of secretion for the peltate scales of C. erythrophyllum. • Histochemical analyses revealed the predominant presence of alkaloids, phenolic compounds and essential oils within the peltate scales of C. erythrophyllum. Combretaceae is a large medicinal family prevalent on the African continent. Traditional healers commonly utilize species of this family to treat or cure a wide array of illnesses and diseases. Medicinal flora are known to contain secondary metabolites which may effectively improve an individual's state of health. These medicinal properties are attributed to secondary metabolites, which in some instances, are exuded by specialized secretory structures, such as trichomes, laticifers or glands. This study investigated the micromorphology, ultrastructure and histochemistry of the secretory structures found on the surface of leaves (emergent, young and mature) and stems of Combretum erythrophyllum. The micromorphological analysis identified two distinct trichome types, peltate scales and non-glandular trichomes. The head cell count of peltate scales appeared to increase upon leaf maturation and ranged from 8 to 19 cells. In addition, the granulocrine pathway was identified as a possible mode of secretion due to the extensive presence of vesicles, vacuoles and electron dense material within the peltate scales. Preliminary histochemical analyses indicated the predominant presence of alkaloids, phenolic compounds and essential oils within the exudate. Medicinally, these metabolites are known to exhibit anti-oxidant, anti-inflammatory properties and anti-microbial properties. In accordance, these beneficial compounds may be further developed for use in medicinal applications. [ABSTRACT FROM AUTHOR]

Published
2020
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44. Chemical composition of essential oil from the leaves of Premna coriacea Clarke

Author

Sadashiva, CT, Sharanappa, P, Naidoo, Y, and Balachandran, Indira

Abstract

In this study, the chemical composition of the essential oil of Premna coriacea leaves was investigated. Extraction by hydrodistillation followed by gas chromatography and mass spectrometry (GC-MS) yielded 27 compounds representing 99.89% of the oil. The major volatile components of the oil were aromadendrene (23.51), caryophyllene (19.27), tetracontane (11.90), 17-pentatriacontene (6.61), 3',8,8'-trimethoxy-3-piperidyl-2,2'- binaphthalene-1,1',4,4'-tetrone (4.68), cis-α-bisabolene (4.65), octadecane, 3-ethyl-5-(2-ethylbutyl)- (4.21), 2-mercaptobenzothiazole (3.17) and tetratetracontane (2.38).Keywords: Premna coriacea, essential oil, aromadendrene, caryophylleneAfrican Journal of Biotechnology Vol. 12(20), pp. 2914-2916

Published
2016

45. The foliar trichomes of Hypoestes aristata (Vahl) Sol. ex Roem. & Schult var aristata (Acanthaceae) a widespread medicinal plant species in tropical sub-Saharan Africa: with comments on its possible phylogenetic significance

Author

Bhatt, A, Naidoo, Y, and Nicholas, A

Subjects
medicinal plant, lcsh:Biology (General), Glandular trichomes, Acanthaceae, fungi, food and beverages, Hypoestes aristata var. aristata, Scanning electron microscope, lcsh:QH301-705.5
Abstract

The micromorphology of foliar trichomes of Hypoestes aristata var. aristata was studied using stereo, light and scanning microscopy (SEM). This genus belongs to the advanced angiosperm family Acanthaceae, for which few micromorphological leaf studies exist. Results revealed both glandular and non-glandular trichomes, the latter being more abundant on leaf veins, particularly on the abaxial surface of very young leaves. With leaf maturity, the density of non-glandular trichomes decreased. Glandular trichomes were rare and of two types: long-stalked capitate and globose-like peltate trichomes. Capitate trichomes were observed only on the abaxial leaf surface, while peltate trichomes were distributed on both adaxial and abaxial leaf surfaces.

Published
2010

50. Ecophysiological responses of the salt marsh grass Spartina maritima to salinity

Author

Naidoo, G, Naidoo, Y, and Achar, P

Abstract

The effects of salinity on growth and productivity of Spartina maritima (Curtis) Fernald were investigated in glasshouse and field experiments in 2008. In the glasshouse study, plants were subjected to 2%, 10%, 20%, 40% and 80% sea water, with tidal simulation, for 10 months. Increase in salinity from 2% to 20% sea water increased biomass accumulation, CO2 exchange, quantum yield of Photosystem II (PSII), electron transport rate (ETR) through PSII, and intrinsic photochemical efficiency of PSII, while further increases in salinity to 80% resulted in significant decreases in these parameters. Concentrations of proline increased significantly with increase in salinity up to 80% sea water. In the field study, soil physicochemical conditions between streamside and inland sites were compared, and the constraints imposed by any differences on plant ecophysiological responses determined. At the inland site, soil water potential (ø), electrical conductivity of the soil, total cations, and the concentrations of Na+, Ca2+, Mg2+ and P, were significantly higher than those of the streamside site, while CO2 exchange, quantum yield of PSII, ETR through PSII, and intrinsic photochemical efficiency of PSII were significantly lower. The results suggest that S. maritima grows optimally at a salinity of about 20% sea water, and that higher salinity decreases growth and photosynthetic performance.Keywords: biomass accumulation, chlorophyll fluorescence, ion relations, photosynthesis, proline, water potentialAfrican Journal of Aquatic Science 2012, 37(1): 81–88

Published
2012

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