The Efficacy of compost, limestone and growth of Leucaena leucocephala (Lam.) de wit, Senna siamea (Lam.) and Eucalyptus grandis W. Hill ex Maid. for the restoration of bacterial functional diversity in the rhizosphere in copper tailings and pyrite soils

The potential of compost, limestone and growth of Leucaena leucocephala (Lam.) de wit, Senna siamea (Lam.) H.S Irwin & Barneby, and Eucalyptus grandis W. Hill ex Maid for the restoration of rhizospheric bacterial functional diversity of pyrite soil and copper tailings was assessed in the field. Pyrite soil and copper tailings were amended with limestone, compost followed by planting of experimental trees after homogenisation. The experimental setup was of split block design with site as a blocking factor; amendment application and growth of trees as the treatment factors. After 12 months of growth, background and rhizospheric pyrite and copper tailings were sampled and their physico-chemical characteristics analysed. The Community Level Physiological Profiles (CLPP) of the same samples were determined using Biolog EcoPlate™. The functional diversity was assessed from the Biolog data using various indices including Average Well Colour Development (AWCD), substrate richness (S) and Shannon-Wiener index (H). Background and rhizospheric untreated pyrite and copper tailings were extremely acidic, with low organic matter content, available phosphorous, total nitrogen, and relatively higher concentrations of available heavy metals and low bacterial functional diversity. Application of amendments and growth of the tree species effectively increased the pH, organic matter content, available phosphorous, total nitrogen, growth of understory plant species, bacterial functional diversity and lowered the available concentrations of heavy metals. AWCD, bacterial species diversity and richness were higher in rhizospheres of leguminous tree species than the non leguminous Eucalyptus grandis, suggesting the suitability of the former for remediation of pyrite and copper tailings. Keywords: efficacy, compost, restoration, bacterial functional diversity, rhizosphere, Biolog Ecoplate

Assessing knowledge and willingness to use genetically modified crops in Uganda

Background: There has been a lot of debate on genetically modified (GM) crops both globally and locally in Uganda. Whereas some of the debates have been informed by scientific research, many are not. The level of acceptance and attitudes of people towards GM crops is a function of their knowledge. However, there is a paucity of studies on the knowledge and attitudes of Ugandans on GM crops. This study aimed to assess the level of knowledge of GM crops in Uganda. Methods: We carried out a mixed methods study in September 2021 in Bushenyi, Jinja and Wakiso districts. We conducted 18 focus group discussions (FGDs), 13 key informant interviews (KIIs) and 698 quantitative interviews. The quantitative interviews were conducted using structured questionnaires. The FGD and KI interviews were audio recorded and transcribed verbatim. The qualitative data were analyzed using framework analysis and the quantitative data were analyzed using modified Poisson regression to identify factors associated with the level of knowledge of GM crops in STATA 15. Results: Out of the 698 respondents interviewed, only 273 (39.1%) had ever heard of GM crops. About 204 (74.7%) of the 273 respondents reported having a moderate–high understanding of GM crops and 62.3% (170) of the respondents further reported that GM crops are harmful to their health and environment, despite some of their intrinsic benefits, such as high productivity, improved income and resilience to pests and diseases. In addition, Out of the 698 respondents interviewed, only 37.7% were wary of the possibility of the emergence of super pests due to the development of resistance to some GM crops. Conclusions: Most of the community members do not have adequate knowledge about GM crops, hence, there is need for sensitization and legislation on GM crops before their release to the public

Population exposure to trace elements in the Kilembe copper mine area, Western Uganda: a pilot study

The mining and processing of copper in Kilembe, Western Uganda, from 1956 to 1982 left over 15 Mt. of tailings containing cupriferous and cobaltiferous pyrite dumped within a mountain river valley. This pilot study was conducted to assess the nature and extent of risk to local populations from metal contamination arising from those mining activities. We determined trace element concentrations in mine tailings, soils, locally cultivated foods,house dust, drinking water and human biomarkers (toenails) using ICP-MS analysis of acid digested samples. The results showed that tailings, containing higher concentrations of Co, Cu, Ni and As compared with world average crust values had eroded and contaminated local soils. Pollution load indices revealed that 51% of agricultural soils sampled were contaminated with trace elements. Local water supplies were contaminated, with Co concentrations that exceeded Wisconsin (US) thresholds in 25% of domestic water supplies and 40% of Nyamwamba river water samples. Zinc exceeded WHO/FAO thresholds of 99.4 mg kg−1 in 36% of Amaranthus vegetable samples, Cu exceeded EC thresholds of 20 mg kg−1 in 19% of Amaranthus while Pb exceeded WHO thresholds of 0.3 mg kg−1 in 47% of Amaranthus vegetables. In bananas, 20% of samples contained Pb concentrations that exceeded the WHO/FAO recommended threshold of 0.3 mg kg−1. However, risk assessment of local foods and water, based on hazard quotients (HQ values) revealed no potential health effects. The high external contamination of volunteers' toenails with some elements (even after a washing process) calls into question their use as a biomarker for metal exposure in human populations where feet are frequently exposed to soil

Mercury Accumulation in Food Crops and Phytoremediation Potential of Wild Plants Thriving in Artisanal and Small-Scale Gold Mining Areas in Uganda

Mercury (Hg) has been used for millennia in artisanal and small-scale gold mining (ASGM) to extract gold from ore as an amalgam that is heated to recover gold. Since there is hardly any sustainable technology that can be used to recover it, the vast percentage of released Hg finds its way into the environment. Currently, ASGM is the largest source of mercury pollution on Earth. Mercury (Hg) is listed among the top 10 most harmful metals by the World Health Organization (WHO), and it is known to cause several neurological disorders in humans. Thus, Hg levels in environmental systems surrounding pollution hotspots such as ASGM mines need to be monitored to ensure their proper management and protect vulnerable ecosystems and human health. This work was aimed to study the level of Hg pollution in soils and plants thriving around ASGM mines in Eastern Uganda and to evaluate the Hg phytoremediation potential of the plants. The total Hg contents were determined for soils, food crops and wild plants growing around ASGM mines. The results for the pH, organic carbon (OC) and electric conductivity (EC) of the soils in the study area were comparable to those of the control soils. The soils in the studied ASGM areas exhibited high Hg concentrations ranging between 723 and 2067 folds more than those of the control soils. All soils were moderately to heavily contaminated according to geoaccumulation (Igeo) index values that ranged between 1.16 and 3.31. The results of this study also showed that the food crops and wild plants accumulated Hg levels that were above the 20 ng/g (0.02 ppm) permissible limit. This study revealed relatively higher levels of Hg in the aerial parts of the plants compared with the underground organs, which can be attributed to Hg deposition, entry through stomata and foliar adsorption. Mercury levels in 47% of the food crop samples were above the FAO/WHO permissible mercury limit of 0.5 µg/g. Similarly, medicinal plants accumulated Hg to levels that were several folds higher than the 0.2 ppm permissible limit of mercury in herbal materials of Canada. Interestingly, this study showed that some wild plant species, especially sedges, exhibited relatively higher levels of mercury accumulation than others thriving in the same environment, an indication that such plants could be utilized in the phytoremediation of Hg-contaminated sites

Sandwich Enzyme-Linked Immunosorbent Assay for Quantification of Callose.

The existing methods of callose quantification include epifluorescence microscopy and fluorescence spectrophotometry of aniline blue-stained callose particles, immuno-fluorescence microscopy and indirect assessment of both callose synthase and β-(1,3)-glucanase enzyme activities. Some of these methods are laborious, time consuming, not callose-specific, biased and require high technical skills. Here, we describe a method of callose quantification based on Sandwich Enzyme-Linked Immunosorbent Assay (S-ELISA). Tissue culture-derived banana plantlets were inoculated with Xanthomonas campestris pv. musacearum (Xcm) bacteria as a biotic stress factor inducing callose production. Banana leaf, pseudostem and corm tissue samples were collected at 14 days post-inoculation (dpi) for callose quantification. Callose levels were significantly different in banana tissues of Xcm-inoculated and control groups except in the pseudostems of both banana genotypes. The method described here could be applied for the quantification of callose in different plant species with satisfactory level of specificity to callose, and reproducibility. Additionally, the use of 96-well plate makes this method suitable for high throughput callose quantification studies with minimal sampling and analysis biases. We provide step-by-step detailed descriptions of the method

Assessing knowledge and willingness to use genetically modified crops in Uganda

Abstract Background There has been a lot of debate on genetically modified (GM) crops both globally and locally in Uganda. Whereas some of the debates have been informed by scientific research, many are not. The level of acceptance and attitudes of people towards GM crops is a function of their knowledge. However, there is a paucity of studies on the knowledge and attitudes of Ugandans on GM crops. This study aimed to assess the level of knowledge of GM crops in Uganda. Methods We carried out a mixed methods study in September 2021 in Bushenyi, Jinja and Wakiso districts. We conducted 18 focus group discussions (FGDs), 13 key informant interviews (KIIs) and 698 quantitative interviews. The quantitative interviews were conducted using structured questionnaires. The FGD and KI interviews were audio recorded and transcribed verbatim. The qualitative data were analyzed using framework analysis and the quantitative data were analyzed using modified Poisson regression to identify factors associated with the level of knowledge of GM crops in STATA 15. Results Out of the 698 respondents interviewed, only 273 (39.1%) had ever heard of GM crops. About 204 (74.7%) of the 273 respondents reported having a moderate–high understanding of GM crops and 62.3% (170) of the respondents further reported that GM crops are harmful to their health and environment, despite some of their intrinsic benefits, such as high productivity, improved income and resilience to pests and diseases. In addition, Out of the 698 respondents interviewed, only 37.7% were wary of the possibility of the emergence of super pests due to the development of resistance to some GM crops. Conclusions Most of the community members do not have adequate knowledge about GM crops, hence, there is need for sensitization and legislation on GM crops before their release to the public

Dementia Prevalence and Risk Factors

Objectives: The burden of dementia is increasing in sub-Saharan Africa (SSA), but there are limited epidemiological data on dementia in SSA. This study investigated the prevalence and associations of dementia in older adults (less than 60 y) attending the outpatient department of Mount Meru Hospital in Tanzania. Methods: This one-phase cross-sectional study screened a sample using the Identification of Dementia in Elderly Africans (IDEA) cognitive screening tool. Those that screened as having possible and probable dementia were further assessed, and diagnosis of dementia was made according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Demographic and risk factor data were collected. Results: Within those screened, 57/1141 (5.0%) (95% CI: 3.7-6.3) had dementia. Female sex [odds ratio (OR)=2.778, 95% CI: 1.074–7.189], having never attended school (OR=6.088, 95% CI: 1.360–27.256), alcohol (U/wk) (OR=1.080, 95% CI: 1.016-1.149), uncorrected visual impairment (OR=4.260, 95% CI: 1.623-11.180), body mass index <18.5 kg/m2 (OR=6.588, 95% CI: 2.089-20.775), and stroke (OR=15.790, 95% CI: 3.48-74.475) were found to be significantly, independently associated with dementia. Conclusions: The prevalence of dementia in this population is similar to a recent community-based rate in Tanzania and lower than a hospital-based rate in Senegal. This is the first time the association between visual impairment and dementia has been reported in SSA. Other associations are in keeping with previous literature

Xanthomonas campestris pv. musacearum Bacterial Infection Induces Organ-Specific Callose and Hydrogen Peroxide Production in Banana

Xanthomonas campestris pv. musacearum (Xcm) bacteria cause banana Xanthomonas wilt (BXW), the most destructive disease of bananas in East and Central Africa. During early stages of infection in susceptible banana cultivars, incomplete systemic movement of Xcm limits bacterial colonization in the upper organs. The mechanistic basis of this delayed movement is unknown. We hypothesized that Xcm infection triggers basal pattern-triggered immune (PTI) responses whose spatial and temporal variability along the banana's anatomical structure accounts for initially limiting Xcm in upper organs. Hence, we examined PTI responses such as callose deposition and hydrogen peroxide (H2O2) production in different organs in response to Xcm infection in BXW-susceptible Kayinja and Mbwazirume banana cultivars and wild resistant progenitor Musa balbisiana. Xcm-induced callose increased and peaked at 14 days postinoculation (dpi) and 28 dpi as assessed by fluorescence microscopy and enzyme-linked immunosorbent assays, respectively. The levels of Xcm-induced H2O2 and callose were highest in the pseudostems and corms, respectively, and were independent of host susceptibility or resistance to BXW.  H2O2 production showed a biphasic transient pattern with an initial increase at 1-hour post Xcm inoculation (hpi), followed by a decline 3 to 6 hpi and then a second increase by 12 hpi. Our findings point to organ-specific responses to Xcm infection in bananas. The corm, which doubles as a subterranean perennating organ and interface between mother plants and lateral shoots, was the most responsive organ in callose production, whereas the pseudostem was the most responsive organ in H2O2 production, suggesting the significance of these organs in banana response to BXW. [Graphic: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license

Disproportionate Distribution of HBV Genotypes A and D and the Recombinant Genotype D/E in the High and Low HBV Endemic Regions of Uganda: A Wake-Up Call for Regional Specific HBV Management

Background. Hepatitis B virus (HBV) is the leading cause of liver-related diseases. In Uganda, there is a regional disparity in the HBV burden. Our study was aimed at establishing the circulating genotypes in a low and a high endemic region to give plausible explanations for the differences in regional burden and guide the future management of the disease. Methods. A total of 200 HBsAg-seropositive subjects were recruited into the study by convenience sampling. The HBsAg Rapid Test Strip (Healgen Scientific Limited Liability Company, Houston, TX77047- USA) was used to screen for HBsAg while the Roche machine (Roche, Basel Switzerland/Abbot Technologies (USA)) was used to determine the viral load. The Chemistry Analyzer B120 (Mindray, China) was used for chemistry analysis. For HBV genotyping, total DNA was extracted from whole blood using the QIAamp® DNA extraction kit. Nested PCR amplification was performed using Platinum Taq DNA Polymerase (Invitrogen Corporation, USA) to amplify the 400 bp HBV polymerase gene. Purification of nested PCR products was performed using Purelink PCR product purification kit (Life Technologies, USA). Automated DNA sequencing was performed using BigDye Terminator v3.1 Cycle Sequencing Kit on 3130 Genetic Analyzer (Applied Biosystems, USA). The NCBI HBV genotyping tool (https://www.ncbi.nlm.nih.gov/projects/genotyping/formpage.cgi) was used for determination of genotype for each HBV sequence. Pearson’s chi-square, multinomial logistic regression, and Mann–Whitney U tests were used for the analysis. All the analyses were done using SPSS version 26.0 and MedCalc software version 19.1.3 at 95% CI. A p<0.05 was considered statistically significant. Results. Majority of our study subjects were female (64.5%), youth (51.0%), and married (62.0%). Overall, genotype A was the most prevalent (46%). Genotype D and the recombinant genotype D/E were proportionately more distributed in the high endemic (38.2%) and low endemic (36.5%) regions, respectively. Genotype D was significantly more prevalent in the high endemic region and among the elderly (p<0.05). Genotype D was significantly associated with elevated viral load and direct bilirubin (p<0.05). The recombinant genotype D/E was significantly associated with elevated viral load (p<0.05). Similarly, genotype A was significantly associated with elevated AST and GGT, lowered viral load, and normal direct bilirubin levels (p<0.05). Conclusion. There is disproportionate distribution of genotypes A and D and the recombinant genotype D/E in the low and high endemic regions of Uganda. This probably could explain the differences in endemicity of HBV in our country signifying the need for regional specific HBV management and control strategies