Natural Sciences
Mak Scientists Unveil New Method of Measuring Stress Levels in Plants
Just like animals and human beings, plants too can be stressed. Whereas one may easily detect stress in animals and humans basing on their behavior, plant “behavior” is not easy to interpret.
Why should we be concerned about stress in plants?
Plants under stress cannot reproduce or grow well because they have to divert much of their physiological energy to fighting stress. If the plants are critical food crops, this will lead to perpetual food shortages because their energy resources are spent fighting stress.
New study on measuring stress in plants
A new study titled “Sandwich Enzyme-Linked Immunosorbent Assay for Quantification of Callose” and led by a team of scientists at the Department of Plant Sciences, Microbiology and Biotechnology at Makerere University in collaboration with the University of California, Davis, USA, shows how stress in plants can be measured. According to Prof. Arthur Tugume, the lead scientist of this study and expert in plant diseases, when plants are stressed, they produce numerous molecules within their cells mostly as means of adapting to stress or avoiding the impact of stress. “For example, plants produce reactive oxygen species like hydrogen peroxide, superoxide ions, and hydroxyl ions. These reactive oxygen species are produced rapidly and act as rapid messengers in the plant tissues to activate additional responses spreading over the entire plant body. This helps the plant to withstand or avoid the impact of stress”.
Dr. Ssenku E. Jamilu, a plant physiology expert on the team explains that in plants, stress can be induced by many factors such as pollution in the soil and atmosphere, high soil salinity (salt stress), excessive lack of water (drought), extreme temperatures, lack of oxygen (anoxia), excess radiation, mechanical injury by wounding or by pests that feed on the plants, and infestation by disease-causing microorganisms (pathogens). “Such factors are worsened by climate change, implying the importance of measuring their impact on individual plants to guide plant breeding programmes to ensure sustainable food production in the face of climate change”.
The research indicates that reactive oxygen species set in motion additional processes to ensure limited impact of stress on the plant. For example, a unique carbohydrate, named “callose” starts to accumulate in large quantities within plant cells as a means of fortifying plant cells. Callose differs from the other usual plant carbohydrates such as starch or cellulose because of the way its structures are formed. Also, the production of callose gets increased during stress. Callose acts as a road-block to any pathogen such as bacteria by limiting bacterial movement that would otherwise ease attack on other tissues or cells.
“If we can artificially induce the stress on the plant, and then measure the amount of reactive oxygen species or callose or any other responses in the plant, we should be able to directly and quantitatively measure the stress,” Prof. Tugume explains.
He however notes that callose participates in many other normal developmental processes of plants and for that reason, there is always some “housekeeping” callose in the plant tissues even without stress. “This means that one must be able to accurately and quantitatively distinguish between ‘stress-induced’ and normal ‘housekeeping’ callose”.
In this study, the researchers used young (2.5-months old) banana plantlets that had been generated from tissue culture at Kawanda Agricultural Research Institute. They then infected the plantlets with a bacterium called Xanthomonas campestris pv. musacearum. This bacterium induces so much stress on the banana plants resulting into a destructive disease known as banana xanthomonas wilt (BXW), the most destructive disease of bananas in East and Central Africa.
The banana leaves, pseudostems and corms were analyzed for callose and compared with the control plants that had been inoculated with water instead of bacteria. The analysis was done using a method called S-ELISA (Sandwich Enzyme-linked immunosorbent Assay), that was designed by scientists in this study. This method is specific to callose.
Callose-specific primary antibodies were used to coat the wells of 96-well microplates followed by incubation with callose extracts from tissues of stressed plants. Additional incubation with same primary callose-specific antibodies was done, and finally, incubation with a secondary antibody that is conjugated to an enzyme. When a substrate is supplied to the enzyme, colour changes were monitored. The presence of callose (and thus stress on the plants) was assessed quantitatively by measuring the intensity of color change resulting from enzymatic action on the substrate. This method proved effective in comparison to the gold standard method of detecting and quantifying aniline blue stained callose using fluorescence microscopy.
This research was part of the PhD studies for Mr. Abubakar S. Mustafa at Makerere University and University of California, Davis. According to Mr. Mustafa, his method is new and can be applied to any plant that is subjected to any stress because generally, plants produce callose in response to stress.” Mr. Mustafa further states that the method is convenient because, if necessary, samples can be processed between a few hours to one year (or even longer), which allows exchange of materials between laboratories and countries when needed, something that was not possible before. The S-ELISA method used 96-well plates which allows high throughout studies, hence, hundreds of samples can be analyzed simultaneously within a few days.
This study has been published as a Protocol by Multidisciplinary Publishing Institute (MDPI) in an open access journal, “Methods and Protocols”, in the section: Biochemical and Chemical Analysis & Synthesis and is freely accessible on https://www.mdpi.com/2409-9279/5/4/54/htm.
The research was funded by the Bill and Melinda Gates Foundation through the National Agricultural Research Organization (NARO), Uganda. The project had partners including the International Institute of Tropical Agriculture, the Alliance for Bioversity International and International Centre for Tropical Agriculture (CIAT) and CABI.
For more details, contact;
- Prof. Arthur Tugume, Lead Scientist of the study, College of Natural Sciences, Makerere University, Email: arthur.tugume@mak.ac.ug, Tel: +256772514841
- Mr. Abubakar S. Mustafa, Co-Author and PhD student on the study, Email: mustafa.abubakar.sadik@gmail.com, Tel: +256702813233
- Hasifa Kabejja, Principal Communication Officer, College of Natural Sciences, Makerere University, Email: pr.cns@mak.ac.ug, Tel: +256774904211
Natural Sciences
Makerere Researchers Call for Urgent Conservation of Medicinal Plants in Eastern Uganda
Researchers from the Department of Plant Sciences, Microbiology, and Biotechnology at the College of Natural Sciences (CoNAS), Makerere University have highlighted the urgent need to conserve medicinal plants in the face of increasing threats from climate change, over-harvesting, and habitat destruction.
Despite Namutumba District’s rich diversity of medicinal plants, conservation efforts are limited, and several species are already classified as globally and nationally threatened. This highlights the urgent need for focused conservation strategies to safeguard these vulnerable medicinal plants.
Under a project titled “Knowledge, Attitudes, and Conservation of Commonly Traded Medicinal Plants in a Climate-Changing Environment in Eastern Uganda,” a team of researchers led by Dr Patience Tugume documented 174 medicinal plant species. The goal was to assess the existential threats facing these plants due to unsustainable harvesting practices and the lack of effective conservation measures. These species are widely used to treat various health conditions, including malaria, syphilis, diabetes, hypertension, and certain cancers. The findings of the study are intended to guide the development of species-specific, evidence-based interventions to curb possible extinction and loss of medicinal plant resources. The research revealed troubling trends in the availability of key medicinal plants, including:
- The herbalists mostly collected their medicinal plants from bushlands (92.0%), markets (82.3%) and wetlands (74.7%) and were rarely cultivated. This is of great concern regarding the conservation and future availability of these resources.
- It was noted that 36% of the herbal products were made from roots, which presents a conservation threat since the heavy utilization of roots affects the regeneration of the medicinal plants.
- Common plants used were: Kigelia africana (Naibere), Erythrina abyssinica (Ekiyirikiti) and Geranium sauveolens (Lokowe). Kigelia africana was the most cited species by the herbalists, indicating heavy utilization and a high conservation threat if deliberate measures are not taken to ensure its future availability.
- Almost all respondents (289, 96.3%) acknowledged a considerable decline in the availability of 13 medicinal plants species including Aloe wollastonii (Ekigagi), Commiphora africana (Nkulidho), Myrica kandtiana (Mukikimbo) and Acacia sieberiana (Mufundawuzi).
- Four plant species i.e. Tamarindus indica (Enkoge), Warburgia ugandensis (Balwegira), Mitragyna rubrastipulata (Mutamatama) and Mondia whitei (Mulondo) appear on the Red List of Globally and Nationally Threatened Species and were mentioned among the plants whose population has greatly declined.
- The causes of decline in availability of medicinal plants included climate change, overharvesting, agricultural expansion, habitat destruction, land use change and inadequate regulations.
- There were no medicinal plant conservation efforts by herbalists.
The study recommended the following practices to ensure conservation of the medicinal plants:
- Promote the use of sustainable harvesting techniques to ensure conservation of medicinal plants.
- Conduct capacity building for stakeholders in the medicinal plants sector on conservation, value addition and standardization.
- Establish community botanical gardens raw plant collection and sensitization programmes.
- Advocate for agroforestry among herbalists to reduce the dependence on natural habitats.
- Develop and enforce regulations on accessing natural areas for medicinal plants.
- Promote conservation awareness campaigns.
Research Dissemination in Namutumba District
At the research dissemination workshop held in Namutumba District on 23rd July 2025, and attended by district leaders, researchers, and local herbalists, the project team led by Dr Patience Tugume expressed hope that the insights gained from the project, particularly in medicinal plants conservation approaches, will be invaluable for minimising the decline in medicinal plants.
In her remarks, Dr Tugume, thanked the Government of Uganda through the Makerere University Research and Innovations Fund (MakRIF) for funding the project. She expressed gratitude to the research team composed of Dr Abubakar Sadik Mustafa, Dr Jamilu E. Ssenku, Dr Savina Asiimwe, and Dr Abdul Walusansa who have worked with her closely from project inception in February 2024. She further thanked the research assistants and all respondents, mainly the herbalists that participated in the study.
In a special way, she appreciated Mr. Fred Aggrey Bangu (Resident District Commissioner), Mr. Ofwono Emmanuel (Chief Administrative Officer), Mr. Kiire Noah (Communication Officer), Mr. Mugunywa Enock (District Community Development Officer), Mr. Kirya Moses (District Environmental Officer), Mr. Bamusubire William (District Forest Officer) and the leaders of herbalist associations for providing support throughout the study and sparing time to attend the dissemination workshop.
Addressing the participants, the Resident District Commissioner, Mr. Fred Aggrey Bangu urged all stakeholders to engage in a collaborative discussion on how the study findings can be translated into practical solutions to promote sustainable use and conservation of commonly used medicinal plants in Namutumba District amidst adverse effects of climate change.
Mr. Ofwono Emmanuel, the Chief Administrative Officer, praised the Makerere research team for selecting Namutumba as the study area. He said the research served as an eye-opener to the district officials and community, especially regarding the pressure exerted on natural medicinal resources.
Report compiled by Dr Patience Tugume and Dr Abubakar Sadik Mustafa – Department of Plant Sciences, Microbiology and Biotechnology, CoNAS, Makerere University
Natural Sciences
Beyond Being a Dean of Science & Vice Chancellor Emeritus, Prof. Luboobi was a Friend. Just That!
Prof. Livingstone Sserwadda Luboobi, Africa’s Icon of Mathematics is gone. The continent has lost a true giant in the field of mathematics, specifically biomathematics. This dynamic and evolving discipline, which applies mathematical principles to the study of biological systems and phenomena, has been deeply shaped by Prof. Luboobi’s legacy. At Makerere University and across Africa, his influence is etched into the fabric of research, mentorship, and innovation. Prof. Luboobi’s contributions have left lasting marks, on the hundreds, perhaps thousands, of lives he touched directly and indirectly. Each of us carries a unique memory, a lesson, or an inspiration drawn from his life and work. We will dearly miss Prof. Luboobi, a brilliant mind, a generous mentor, and a true icon of African science.
To me and my peers, he was our Dean, Faculty of Science in 1995, and he read-out our names at our graduation in January 1999. Later in 2004 as Vice Chancellor, he signed off my official 4-year PhD study leave in Scandinavia. When the 4 years elapsed before I could complete, we returned to the table and successfully negotiated for extra 2 years of grace which enabled me to complete in excellence in January 2010.
Lately, after his retirement, we found ourselves closely intimate, sharing deeper thoughts on a number of social, development, strategic leadership and governance, and academic matters. As a plant biologist, spending time with a retired Professor of Mathematics, one could wonder what we would possibly have to talk about. And yet, our discussions were rich and thought-provoking. One moment that left a lasting impression on me was his quiet humility. Despite the respect and priority I extended to him, he never assumed entitlement. If he sensed I was busy, he would simply wait outside my office, whether at the Botany Building or my current Dean’s office at CONAS, without interrupting. That gesture spoke volumes.
We often talked about science, and I had much to learn from him. I asked how he had managed to start and sustain the Uganda Mathematical Society (UMS), since we were in the process of setting up the Biology Society of Uganda (BioSU) at the time. I also wanted to hear about his journey – from his undergraduate days to becoming a retired professor. As he shared his story, pausing to catch his breath after long sentences, I sensed he was deeply concerned about something. His concern was that, as of 2017, nearly all senior academics at Makerere University had begun their careers humbly as teaching assistants and risen through the ranks in various disciplines, but that opportunity had since been lost.
He believed that trying to establish a sustainable staffing system without a pool of junior staff, selected directly from the best-performing undergraduate students, was a risky path for the university’s future. With a troubled tone, he said: “I wonder how you people will manage university staffing in the long term when you have removed the foundation…” There were many lessons in that conversation for me.
In October 2023, I started assembling a grant application together with my European and American colleagues (5 Universities) for submission to National Science Foundation (NSF, USA), addressing a certain plant disease conundrum in East Africa. I realized Prof. Luboobi’s expertise in Biomathematics could be relevant. I co-opted him along with another colleague from the Department of Mathematics. I was fascinated at the express knowledge he displayed in modelling biological systems, and in our case, plant disease modelling. Much as his physical strength was less, the intellect was razor-sharp. Even though we didn’t succeed on that attempt, I had numerous other lessons to learn from his seniority.
We shared personal stories. I re-learnt that living simple as much as possible helps a lot. Although this was not new, hearing it from one you respect takes on a whole new meaning. If I died today, I wonder what my peers or junior colleagues would say about me? I would not hear it, though. I am happy I had chance to tell Prof. Luboobi what he meant to me when he was still alive.
I regret his death. We usually say it is untimely, but will death of a loved one ever be timely? Holy Scripture says, “Seeing his days are determined, the number of his months is with You; You have appointed his bounds that he cannot pass.” – Job 14:5. This is an emphasis of God’s sovereignty over life and death, highlighting that He determines the length of a person’s life and sets unchangeable limits, just as He does in setting boundaries and limits for all His creation. Prof. Luboobi could not cross the boundary set by the creator.
I am grateful that the Principal, College of Natural Sciences (CoNAS), Makerere University and his team did their best to mobilize support at the most critical moment of need. I am grateful to God for gifting Makerere University with Prof. Luboobi, and for allowing me in particular a chance to walk a little close with him in his evening days of his life between 2023-2025.
Good bye Prof. Livingstone S. Luboobi! Go and serve God with the angels. We will also join you, in the course of time! See you later when that time comes!
*****15 students from different departments at CoNAS are showcasing their projects.
Over 300 Ugandan innovators, among them students from the College of Natural Sciences (CoNAS) and other science-based colleges at Makerere University are participating in the 2025 National Science Week exhibition, currently underway at the Kololo Independence Grounds.
Launched in 2021, the National Science Week is an annual event organized by the Science, Technology, and Innovation (STI) Secretariat under the Office of the President. The exhibition serves as a strategic platform for showcasing Uganda’s advancements in science, technology, and innovation, both at the national level and on the global stage.
Held under the theme “Made in Uganda: Innovation to Market”, the 2025 edition (running from 15th-20th June) aims to highlight the country’s growing capacity to transform home-grown scientific ideas and research into viable, market-ready products and technologies.
Key highlights from the official launch of the National Science Week
During the official launch held on 13th May 2025, the Minister of Science, Technology, and Innovation, Hon. Dr. Monica Musenero Masanza, outlined several milestones Uganda has achieved over the past year, including:
- The commencement of clinical trials for locally developed therapeutics, marking a significant step in Uganda’s biopharmaceutical sector.
- Notable growth in the electric vehicle (EV) industry, including the deployment of over 5,000 electric motorcycles and 27 electric buses across the country.
- Establishment of critical green infrastructure, including 140 battery swapping stations and more than 30 direct current (DC) fast chargers nationwide.
According to the Minister, these developments demonstrate Uganda’s advancing capabilities in green technology and sustainable mobility solutions.
The Minister also highlighted additional achievements by the STI Secretariat, including the revitalization of Sukulu Phosphates, the launch of both the Deep Tech and Climate Tech summits, and the operationalization of vaccine production lines for both human and animal health. Dr. Musenero expressed gratitude to the Government of Uganda for its continued support, emphasizing its strategic vision of leveraging science, technology, and innovation as a transformative vehicle to position Uganda as a continental leader in deep tech innovation.
The 2025 National Science Week Activities
The National Science Week is designed to be an interactive experience for all attendees. According to Ms. Cathy Muhumuza from the STI, the exhibition will feature various activities including the official opening by the President of the Republic of Uganda, H.E. Yoweri Kaguta Tibuhaburwa Museveni, expected to take place on Thursday, 19th June 2025. Other activities will include policy dialogues, the Academia Day dedicated to young innovators, and the Investor Day providing a platform for innovators to connect with potential investors.
Additionally, the event will host a “Made in Uganda Supermarket,” allowing visitors to purchase products directly from exhibitors.
CoNAS Students’ projects
Among the many innovators featured at the exhibition are several talented student teams from CoNAS, presenting a diverse array of projects across scientific disciplines, including biotechnology and green energy. Guided by their lecturers and coordinated by Prof. Juma Kasozi, Deputy Principal of CoNAS, the students are showcasing the following projects:
- Anti-fungal and Anti-bacterial Gel Research Project
Team Leader: Mwebaze Bruce
Team Members: Atim Martha, Sebastian Jordan
This project explores the development of a topical gel with both anti-fungal and anti-bacterial properties, aimed at improving public health outcomes in communities with limited access to conventional treatments. - Minoxidil Production for Hair Regrowth
Team Leader: Keinembabazi Melissa
Team Members: Hashima Nanyiri, Nkamusiima Andrew
Focused on producing affordable, locally made Minoxidil, this project aims to provide a cost-effective solution for treating hair loss. - Infrared Biosensor for Aflatoxin Detection
Team Leader: Rubeihayo Randolp
Team Members: Namuleme Martha, Wabitereza Teddy
This innovation utilizes spectrophotometry to develop an infrared biosensor capable of detecting harmful aflatoxins in food, contributing to food safety and public health. - Biofuel Production from Water Hyacinth
Team Leader: Bill Garvin
Team Members: Kalanguka Patience Pearl, Nuwagaba Victor
The project converts invasive water hyacinth into sustainable biofuels using hydrothermal liquefaction, offering an environmentally friendly alternative energy source. - Automobile Fuel Gauge Detector
Team Leader: Ayebare Sam
Team Members: Achieng Rosemary, Nakirinda Winnie
This project involves the development of a reliable fuel gauge detector to improve vehicle fuel management and efficiency.
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