Genetic diversity in 14 tomato (Lycopersicon esculentum Mill.) varieties in Nigerian markets by RAPD-PCR technique

A total of 226 tomato (Lycopersicon esculentum Mill.) fruits sold in markets within three states in Southwestern Nigeria were purchased and differentiated into 14 varietal groups based on morphological parameters. The genomic DNA from the young apical leaves of the seeded plants were extracted and analyzed by the randomly amplified polymorphic DNA-polymerase chain reaction (RAPDPCR) technique. Seventy-four (74) amplified products were scored with 62.2% of them revealing polymorphism. The OPB-18 primer recorded the highest polymorphism (83.3%) and OPU-14 the least (44.4%). The dendrogram revealed 3 clusters. The genotypic relationships between varieties within clusters ranged from 2 in clusters 1 and 3 to 10 in cluster 2. Cluster 2 revealed 4 subgroups with two pairs of varieties (var. c and i and l and m) showing 100% similarities. The local names, place of cultivation and phenotypic characters expressed by the varieties were not suitable for varietal differentiation since phenotypically different fruits showed genotypic relatedness. The impression that tomato varieties from a particular geographical zone are genetically similar was therefore nullified.Key words: Tomato, randomly amplified polymorphic DNA, polymerase chain reaction, molecular, genetic diversity, Lycopersicum

Estimating the risk of aflatoxin-induced liver cancer in Tanzania based on biomarker data

Evidence about the magnitude of the aflatoxin menace can help policy makers appreciate the importance of the problem and strengthen policies to support aflatoxin mitigation measures. In this study, we estimated aflatoxin-induced liver cancer risk in 2016 for Tanzania and used the information to estimate the health burden due to the aflatoxin exposure in the country. The burden of aflatoxin-induced liver cancer was assessed based on available aflatoxin biomarker data from a previous epidemiology study, hepatitis B virus infection prevalence and population size of Tanzania in 2016. The health burden due to aflatoxin-induced liver cancer was estimated using disability adjusted life years (DALYs). The aflatoxin exposures ranged from 15.0–10,926.0 ng/kg bw/day (median, 105.5 ng/kg bw/day). We estimated that in 2016 there were about 1,480 (2.95 per 100,000 persons) new cases of aflatoxin-induced liver cancer in Tanzania and assumed all of them would die within a year. These morbidity and mortality rates led to a total loss of about 56,247.63 DALYs. These results show, quantitatively, the cases of liver cancer and related deaths that could be avoided, and the healthy life years that could be saved, annually, by strengthening measures to control aflatoxin contamination in Tanzania

Biomass Smoke Exposure Is Associated With Gastric Cancer and Probably Mediated Via Oxidative Stress and DNA Damage: A Case-Control Study.

PURPOSE: We investigated the association between gastric cancer and environmental and dietary exposures. In addition, we explored probable mechanistic pathways for the influence of biomass smoke on gastric carcinogenesis. PATIENTS AND METHODS: The study was conducted in Lusaka, Zambia. Questionnaires were used to collect data on risk factors, whereas enzyme-linked immunosorbent assays and high-performance liquid chromatography were used to measure biologic exposures. Study data were analyzed using contingency tables and logistic regression. RESULTS: We enrolled 72 patients with gastric adenocarcinoma and 244 controls. Gastric cancer was positively associated with rural residence (odds ratio [OR], 2.9; 95% CI, 1.5 to 5.3), poverty (OR, 4.2; 95% CI, 1.9 to 9.1), and daily consumption of processed meat (OR, 6.4; 95% CI, 1.3 to 32) and negatively associated with consumption of green vegetables (OR, 0.2; 95% CI, 0.1 to 0.5). Gastric cancer was also associated with biomass smoke exposure (OR, 3.5; 95% CI, 1.9 to 6.2; P < .0001), an association that was stronger for intestinal-type cancers (OR, 3.6; 95% CI, 1.5 to 9.1; P = .003). Exposure to biomass smoke in controls was associated with higher urinary levels of 8-isoprostane (P < .0001), 8-hydroxydeoxyguanosine (P = .029), and 1-hydroxypyrene (P = .041). Gastric cancer was not associated with biochemical measures of current exposure to aflatoxins or ochratoxins. CONCLUSION: In Zambia, exposure to biomass smoke, daily consumption of processed meat, and poverty are risk factors for gastric cancer, whereas daily consumption of green vegetables is protective against gastric cancer. Exposure to biomass smoke was associated with evidence of oxidative stress and DNA damage, suggesting mechanistic plausibility for the observed association, and the association was restricted to intestinal-type gastric cancer

Significance of terrestrial inflows to carbon and nitrogen distribution in the Lake Victoria surface water

This was an investigation to characterize seasonal and spatial distribution of particulate organic matter (POM) in the surface water of Lake Victoria at Speke Gulf, by using carbon-13 and nitrogen-15 isotopic signatures. Speke Gulf is under the influence of terrestrial inflow through river Simiyu. The POM from the lake surface water had higher C:N ratio values decreasing towards the deeper lake water, an indication of decreasing nitrogen content relative to carbonic materials. Samples away from the river mouth provided C:N ratios within the Redfield ratio range (C:N:P; 106:16:1) indicating materials of phytoplanktonic origin. The POM isotopes composition indicated a maximum &auml;13C value of .21.2&permil; close to the river mouth and lowest value (~ .25&permil;) away from the river influence. The &auml;15N maximum (14.7&permil;) was observed near the river mouth with lower values (5.8&permil;) found in deeper waters away from the river mouth. Overall, there was a general decrease of 13C and &auml;15N values from shallow water to deeper water. There was higher &auml;15N value dispersion (std. Dev. &plusmn;3.4&permil;) compared to &auml;13C values with std. Dev.&plusmn;1.2&permil;. These values also varied with seasons, a phenomenon showing significant influence of land run off on the lake elemental distribution, carbon and nitrogen in particular