Using the conventional methods for parasitological examinations of the salt floatation and direct... more Using the conventional methods for parasitological examinations of the salt floatation and direct smear, ten ostriches infected with internal parasites were identified. Ten birds that were without internal parasites were used as the controls. The metabolizing enzymes glutathione peroxidase (GPX), DT -diaphorase (DTD) and succinate dehydrogenase (SDH) were assayed accordingly using liver samples from the control and infected birds. Malondialdehyde (MDA), a marker of lipid peroxdation, was also assayed. Results showed that cestode eggs occurred at twice the amount of nematode eggs in the faeces of infected ostriches. Infected birds showed significantly higher DTD activity when compared to non-infected birds (Student’s t test, p < 0.05) whilst the activities of SDH and GPX were statistically not altered (Student’s t test p > 0.05). MDA levels were significantly elevated in infected birds compared to controls (Student’s t test, p < 0.001). These results suggest that infected bi...
The presence of aflatoxin producing Aspergillusspp in sixty samples of six selected traditional f... more The presence of aflatoxin producing Aspergillusspp in sixty samples of six selected traditional foods sold on the Bulawayo open market in Zimbabwe was investigated. Ten samples of each of the following commodities were bought from the market; dried groundnuts, dried cowpeas, dried maize, dried cowpea leaves, dried mopane worms and dried Cleome gynandra leaves and analysed for the presence of aflatoxigenic aspergillus. Moisture content of the samples was determined and another portion of the samples was plated on petri dishes containing Sabouraud Dextrose Agar (SDA) and incubated at 28˚C. A total of 35 isolates was obtained and these were characterised according to their morphology as well as the type of aflatoxins they produced as determined by thin layer chromatography. Four distinct morphological groups were found and they were classified as Aspergillu sparasiticus (57%); Aspergillusniger (17%); Aspergillus tamarii (17%) and Aspergillusflavus (8%). These results were validated by ...
AfJatoxins were analyzed in groundnuts stored for either local or export sales in the period 1982... more AfJatoxins were analyzed in groundnuts stored for either local or export sales in the period 1982/83 to 1986/87. Four hundred and forty-one samples of seven groundnut varieties were collected for analysis. Sixty-eight percent of the samples had total concentrations of aIlatoxin BJ and OJ of up to 25 JIg kg-J. In the 1986/87 groundnut crop, the Flamingo and Makulu Red varieties, which constitute the bulk of export sales, had up to 25 JIgkg-J aIlatoxin BJ in 79%of the samples, plus aIlatoxin OJ in 67% of the samples. Overall, the Egret variety was the most susceptible to aIlatoxin contamination during this period. Resume Contamination des arachides stockees par les aflatoxines au Zimbabwe: Les analyses des aIlatoxines ont ete effectuees sur les arachides stockees, destinees soit a la vente locale, soit a l'exportation, au CoUTSde la periode allant de 1982/83 a 1986/87. Elles ont porte sur 441 echantillons de 7 varietes d'arachide. Dans 68% des echantillons, la concentration to...
Research communications in chemical pathology and pharmacology, 1986
This study examined activation of aflatoxin B1 (AFB1) in livers of Schistosoma mansoni-infected a... more This study examined activation of aflatoxin B1 (AFB1) in livers of Schistosoma mansoni-infected and noninfected mice by measuring covalent binding of [3H]AFB1 to cellular macromolecules in vivo and in vitro. During a one week time period after AFB1 treatment of animals, maximal binding of [3H]AFB1 to DNA, RNA and protein in liver occurred during the 1-6 hour period after treatment, with less binding throughout of AFB1 to macromolecules of infected mice. Experiments performed in vitro to determine the capacity of liver microsomes to mediate the binding of AFB1 to calf thymus DNA showed that microsomes from infected mice mediated the binding of less [3H]AFB1 to DNA than those from noninfected animals.
International Journal of Biological and Chemical Sciences, 2007
Samples of fresh faeces were obtained from a free-range chicken source, three commercial chicken ... more Samples of fresh faeces were obtained from a free-range chicken source, three commercial chicken farms and a commercial ostrich farm, all located around Bulawayo City, Zimbabwe, in order to determine the antibiotic resistance profile of selected bacterial isolates of interest in food-related human infections. Samples were prepared at various dilutions and plated on selective media for Coryneforms, Escherichia coli, Enterococcus faecalis and Pseudomonas. The targeted bacteria were isolated as pure cultures and tested for antibiotic resistance to ampicillin, chloramphenicol, oxytetracycline, sulphonamide, streptomycin and tetracycline. Isolates from the faeces of chickens and ostriches in the commercial farms were found to be generally more resistant to streptomycin, tetracycline and oxytetracycline as compared to those from the freerange chickens. This study emphasizes the need to monitor antibiotic resistance genes in the environment and to curb/curtail antibiotic use for growth promotion in farm animals, particularly in developing countries, as continued use will only add to the growing problem of microbial antibiotic resistance.
Peanut butter was monitored for aflatoxin contamination at different stages during its large-scal... more Peanut butter was monitored for aflatoxin contamination at different stages during its large-scale production starting from raw shelled peanuts up to the final product. Twenty five samples, weighing 2 kg each, were taken from each of the following stages: roasting at 160˚C, blanching/de-skinning and grinding. The sub-samples were ground, thoroughly mixed and further reduced by the quartering technique until a 1 kg sub-sample was obtained. This was then analyzed for aflatoxins using reverse phase HPLC incorporating pre-column trifluoroacetic acid derivatization. The results showed a total aflatoxin percentage reduction of 51% after roasting, 27% after blanching/de-skinning followed by a further 11% after grinding to make peanut butter. This meant that there was a cumulative total reduction of 89% of aflatoxin concentration during the production process of peanut butter. These results show that there is a significant reduction of aflatoxin levels at the roasting and blanching stages in the process of producing peanut butter.
International Journal of Biological and Chemical Sciences, 2010
A hundred and seven sheep slaughtered at the Cold Storage Company (CSC) in Bulawayo, were examine... more A hundred and seven sheep slaughtered at the Cold Storage Company (CSC) in Bulawayo, were examined for nematode parasite infections using coporological methods. Direct smear and salt floatation methods were used to observe nematode parasite eggs. Nine sheep were found to be infested with nematode eggs only. Nine uninfected sheep were used as controls. Liver samples collected from the infected and noninfected sheep were used for assays of the antioxidant enzymes, glutathione peroxidase (GPX) and diphosphotriphosho-diaphorase (DTD) as well as the intermediary metabolic enzyme, succinate dehydrogenase (SDH). Lipid peroxidation was assayed by determining malondialdehyde (MDA) levels. Significantly higher GPX activities were observed in infected sheep when compared with non-infected sheep (p < 001). No difference in the activity of DTD was observed in both infected and non-infected sheep (p>0.05). Parasitic infection resulted in significant reduction in SDH activity (p <0.05) and significantly higher MDA levels (p < 0.01). This study suggests that parasitic infections induce oxidative stress.
Bulletin of Environmental Contamination and Toxicology, 2009
The aim of this study was to measure antioxidant enzyme activities as biological indicators of po... more The aim of this study was to measure antioxidant enzyme activities as biological indicators of pollution in tissues of two species of fish. Five Clarius gariepinus and three Oreochromis mossambicus were collected from Umguza Dam (polluted dam) whilst seven C. gariepinus and eight O. mossambicus were collected from Wright Dam (relatively pristine dam). Diphosphotriphoshodiaphorase and catalase activities were consistently lower (42 ± 2% and 78 ± 20%, respectively) in liver whilst malondialdehyde levels were two times higher in muscles of both species of fish collected from Umguza Dam. However, seleniumdependent glutathione peroxidase (Se-GPX) activity was elevated four-fold in liver and gills of O. mossambicus collected from Umguza Dam. Metal levels were two to five times higher in muscles of both species of fish collected from Umguza Dam. Fish from Umguza Dam seem to have responded to pollution by increasing Se-GPX specific activity in an effort to detoxify peroxides produced as a result of metal induced oxidative stress.
Background: The bioconversion efficiency of yellow maize b-carotene to retinol in humans is unkno... more Background: The bioconversion efficiency of yellow maize b-carotene to retinol in humans is unknown. Objective: The objective of this study was to determine the vitamin A value of yellow maize b-carotene in humans. Design: High b-carotene-containing yellow maize was grown in a hydroponic medium with 23 atom% 2 H 2 O during grain development. Yellow maize b-carotene showed the highest abundance of enrichment as [ 2 H 9 ]b-carotene. Eight healthy Zimbabwean men volunteered for the study. On day 1 after a fasting blood draw, subjects consumed 300 g yellow maize porridge containing 1.2 mg b-carotene, 20 g butter, and a 0.5-g corn oil capsule. On day 8, fasting blood was drawn, and subjects consumed 1 mg [ 13 C 10 ]retinyl acetate in a 0.5-g corn oil capsule and 300 g white maize porridge with 20 g butter. Thirty-six blood samples were collected from each subject over 36 d. Concentrations and enrichments of retinol and b-carotene in labeled doses and serum were determined with the use of HPLC, gas chromatography-mass spectrometry, and liquid chromatographymass spectrometry. Results: The area under the curve (AUC) of retinol from 1.2 mg yellow maize b-carotene was 72.9 nmol Á d, and the AUC of retinol from 1 mg retinyl acetate 13 C 10 was 161.1 nmol Á d. The conversion factor of yellow maize b-carotene to retinol by weight was 3.2 6 1.5 to 1. Conclusion: In 8 healthy Zimbabwean men, 300 g cooked yellow maize containing 1.2 mg b-carotene that was consumed with 20.5 g fat showed the same vitamin A activity as 0.38 mg retinol and provided 40-50% of the adult vitamin A Recommended Dietary Allowance. This trial was registered at clinicaltrials.gov as NCT00636038.
Using the conventional methods for parasitological examinations of the salt floatation and direct... more Using the conventional methods for parasitological examinations of the salt floatation and direct smear, ten ostriches infected with internal parasites were identified. Ten birds that were without internal parasites were used as the controls. The metabolizing enzymes glutathione peroxidase (GPX), DT -diaphorase (DTD) and succinate dehydrogenase (SDH) were assayed accordingly using liver samples from the control and infected birds. Malondialdehyde (MDA), a marker of lipid peroxdation, was also assayed. Results showed that cestode eggs occurred at twice the amount of nematode eggs in the faeces of infected ostriches. Infected birds showed significantly higher DTD activity when compared to non-infected birds (Student’s t test, p < 0.05) whilst the activities of SDH and GPX were statistically not altered (Student’s t test p > 0.05). MDA levels were significantly elevated in infected birds compared to controls (Student’s t test, p < 0.001). These results suggest that infected bi...
The presence of aflatoxin producing Aspergillusspp in sixty samples of six selected traditional f... more The presence of aflatoxin producing Aspergillusspp in sixty samples of six selected traditional foods sold on the Bulawayo open market in Zimbabwe was investigated. Ten samples of each of the following commodities were bought from the market; dried groundnuts, dried cowpeas, dried maize, dried cowpea leaves, dried mopane worms and dried Cleome gynandra leaves and analysed for the presence of aflatoxigenic aspergillus. Moisture content of the samples was determined and another portion of the samples was plated on petri dishes containing Sabouraud Dextrose Agar (SDA) and incubated at 28˚C. A total of 35 isolates was obtained and these were characterised according to their morphology as well as the type of aflatoxins they produced as determined by thin layer chromatography. Four distinct morphological groups were found and they were classified as Aspergillu sparasiticus (57%); Aspergillusniger (17%); Aspergillus tamarii (17%) and Aspergillusflavus (8%). These results were validated by ...
AfJatoxins were analyzed in groundnuts stored for either local or export sales in the period 1982... more AfJatoxins were analyzed in groundnuts stored for either local or export sales in the period 1982/83 to 1986/87. Four hundred and forty-one samples of seven groundnut varieties were collected for analysis. Sixty-eight percent of the samples had total concentrations of aIlatoxin BJ and OJ of up to 25 JIg kg-J. In the 1986/87 groundnut crop, the Flamingo and Makulu Red varieties, which constitute the bulk of export sales, had up to 25 JIgkg-J aIlatoxin BJ in 79%of the samples, plus aIlatoxin OJ in 67% of the samples. Overall, the Egret variety was the most susceptible to aIlatoxin contamination during this period. Resume Contamination des arachides stockees par les aflatoxines au Zimbabwe: Les analyses des aIlatoxines ont ete effectuees sur les arachides stockees, destinees soit a la vente locale, soit a l'exportation, au CoUTSde la periode allant de 1982/83 a 1986/87. Elles ont porte sur 441 echantillons de 7 varietes d'arachide. Dans 68% des echantillons, la concentration to...
Research communications in chemical pathology and pharmacology, 1986
This study examined activation of aflatoxin B1 (AFB1) in livers of Schistosoma mansoni-infected a... more This study examined activation of aflatoxin B1 (AFB1) in livers of Schistosoma mansoni-infected and noninfected mice by measuring covalent binding of [3H]AFB1 to cellular macromolecules in vivo and in vitro. During a one week time period after AFB1 treatment of animals, maximal binding of [3H]AFB1 to DNA, RNA and protein in liver occurred during the 1-6 hour period after treatment, with less binding throughout of AFB1 to macromolecules of infected mice. Experiments performed in vitro to determine the capacity of liver microsomes to mediate the binding of AFB1 to calf thymus DNA showed that microsomes from infected mice mediated the binding of less [3H]AFB1 to DNA than those from noninfected animals.
International Journal of Biological and Chemical Sciences, 2007
Samples of fresh faeces were obtained from a free-range chicken source, three commercial chicken ... more Samples of fresh faeces were obtained from a free-range chicken source, three commercial chicken farms and a commercial ostrich farm, all located around Bulawayo City, Zimbabwe, in order to determine the antibiotic resistance profile of selected bacterial isolates of interest in food-related human infections. Samples were prepared at various dilutions and plated on selective media for Coryneforms, Escherichia coli, Enterococcus faecalis and Pseudomonas. The targeted bacteria were isolated as pure cultures and tested for antibiotic resistance to ampicillin, chloramphenicol, oxytetracycline, sulphonamide, streptomycin and tetracycline. Isolates from the faeces of chickens and ostriches in the commercial farms were found to be generally more resistant to streptomycin, tetracycline and oxytetracycline as compared to those from the freerange chickens. This study emphasizes the need to monitor antibiotic resistance genes in the environment and to curb/curtail antibiotic use for growth promotion in farm animals, particularly in developing countries, as continued use will only add to the growing problem of microbial antibiotic resistance.
Peanut butter was monitored for aflatoxin contamination at different stages during its large-scal... more Peanut butter was monitored for aflatoxin contamination at different stages during its large-scale production starting from raw shelled peanuts up to the final product. Twenty five samples, weighing 2 kg each, were taken from each of the following stages: roasting at 160˚C, blanching/de-skinning and grinding. The sub-samples were ground, thoroughly mixed and further reduced by the quartering technique until a 1 kg sub-sample was obtained. This was then analyzed for aflatoxins using reverse phase HPLC incorporating pre-column trifluoroacetic acid derivatization. The results showed a total aflatoxin percentage reduction of 51% after roasting, 27% after blanching/de-skinning followed by a further 11% after grinding to make peanut butter. This meant that there was a cumulative total reduction of 89% of aflatoxin concentration during the production process of peanut butter. These results show that there is a significant reduction of aflatoxin levels at the roasting and blanching stages in the process of producing peanut butter.
International Journal of Biological and Chemical Sciences, 2010
A hundred and seven sheep slaughtered at the Cold Storage Company (CSC) in Bulawayo, were examine... more A hundred and seven sheep slaughtered at the Cold Storage Company (CSC) in Bulawayo, were examined for nematode parasite infections using coporological methods. Direct smear and salt floatation methods were used to observe nematode parasite eggs. Nine sheep were found to be infested with nematode eggs only. Nine uninfected sheep were used as controls. Liver samples collected from the infected and noninfected sheep were used for assays of the antioxidant enzymes, glutathione peroxidase (GPX) and diphosphotriphosho-diaphorase (DTD) as well as the intermediary metabolic enzyme, succinate dehydrogenase (SDH). Lipid peroxidation was assayed by determining malondialdehyde (MDA) levels. Significantly higher GPX activities were observed in infected sheep when compared with non-infected sheep (p < 001). No difference in the activity of DTD was observed in both infected and non-infected sheep (p>0.05). Parasitic infection resulted in significant reduction in SDH activity (p <0.05) and significantly higher MDA levels (p < 0.01). This study suggests that parasitic infections induce oxidative stress.
Bulletin of Environmental Contamination and Toxicology, 2009
The aim of this study was to measure antioxidant enzyme activities as biological indicators of po... more The aim of this study was to measure antioxidant enzyme activities as biological indicators of pollution in tissues of two species of fish. Five Clarius gariepinus and three Oreochromis mossambicus were collected from Umguza Dam (polluted dam) whilst seven C. gariepinus and eight O. mossambicus were collected from Wright Dam (relatively pristine dam). Diphosphotriphoshodiaphorase and catalase activities were consistently lower (42 ± 2% and 78 ± 20%, respectively) in liver whilst malondialdehyde levels were two times higher in muscles of both species of fish collected from Umguza Dam. However, seleniumdependent glutathione peroxidase (Se-GPX) activity was elevated four-fold in liver and gills of O. mossambicus collected from Umguza Dam. Metal levels were two to five times higher in muscles of both species of fish collected from Umguza Dam. Fish from Umguza Dam seem to have responded to pollution by increasing Se-GPX specific activity in an effort to detoxify peroxides produced as a result of metal induced oxidative stress.
Background: The bioconversion efficiency of yellow maize b-carotene to retinol in humans is unkno... more Background: The bioconversion efficiency of yellow maize b-carotene to retinol in humans is unknown. Objective: The objective of this study was to determine the vitamin A value of yellow maize b-carotene in humans. Design: High b-carotene-containing yellow maize was grown in a hydroponic medium with 23 atom% 2 H 2 O during grain development. Yellow maize b-carotene showed the highest abundance of enrichment as [ 2 H 9 ]b-carotene. Eight healthy Zimbabwean men volunteered for the study. On day 1 after a fasting blood draw, subjects consumed 300 g yellow maize porridge containing 1.2 mg b-carotene, 20 g butter, and a 0.5-g corn oil capsule. On day 8, fasting blood was drawn, and subjects consumed 1 mg [ 13 C 10 ]retinyl acetate in a 0.5-g corn oil capsule and 300 g white maize porridge with 20 g butter. Thirty-six blood samples were collected from each subject over 36 d. Concentrations and enrichments of retinol and b-carotene in labeled doses and serum were determined with the use of HPLC, gas chromatography-mass spectrometry, and liquid chromatographymass spectrometry. Results: The area under the curve (AUC) of retinol from 1.2 mg yellow maize b-carotene was 72.9 nmol Á d, and the AUC of retinol from 1 mg retinyl acetate 13 C 10 was 161.1 nmol Á d. The conversion factor of yellow maize b-carotene to retinol by weight was 3.2 6 1.5 to 1. Conclusion: In 8 healthy Zimbabwean men, 300 g cooked yellow maize containing 1.2 mg b-carotene that was consumed with 20.5 g fat showed the same vitamin A activity as 0.38 mg retinol and provided 40-50% of the adult vitamin A Recommended Dietary Allowance. This trial was registered at clinicaltrials.gov as NCT00636038.
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