Pub Date : 2020-06-03DOI: 10.5772/intechopen.86637
A. O. Adejuwon, V. Tsygankova
Aflatoxins are produced by a variety of fungal species and these have contrib-uted to devastating health problems globally. However, apart from the capability of the production of aflatoxins, the productions of enzymes by like fungi have been explored. Aflatoxin B1-producing-toxigenic strains of Aspergillus flavus (A 1 ), Aspergillus parasiticus (A 2 ), Penicillium citrinum (P 1 ) and Penicillium rubrum (P 2 ) isolated from rice were grown on a defined medium with varying carbon and nitrogen sources. They were also grown on rice as sole carbon and nitrogen source for fungal growth. In an attempt to purify, the extracellular α -amylases produced were subjected to ammonium sulfate precipitation (40–90% saturation) followed by dialysis. The aflatoxin B1-producing toxigenic strains of Aspergillus flavus (A 1 ), Aspergillus parasiticus (A 2 ), Penicillium citrinum (P 1 ) and Penicillium rubrum (P 2 ) were able to produce α -amylases in both the growth medium with varying C and N sources of fungal and also in the rice medium. The most active α -amylase activity was produced by toxigenic A. flavus (A 1 ) with a value of 3.25 ± 0.15 Units and this was when ammonium sulfate was nitrogen source with starch as carbon source of fungal growth in the defined growth medium. These toxigenic fungal strains can be explored for the industrial production of α -amylases. the production and activity of α -amylases by some toxigenic aflatoxin B1-producing strains of Aspergillus and Penicillium isolated from deterioration rice. Attempts were made to purify the α -amylases.
{"title":"α-Amylase Production by Toxigenic Strains ofAspergillusandPenicillium","authors":"A. O. Adejuwon, V. Tsygankova","doi":"10.5772/intechopen.86637","DOIUrl":"https://doi.org/10.5772/intechopen.86637","url":null,"abstract":"Aflatoxins are produced by a variety of fungal species and these have contrib-uted to devastating health problems globally. However, apart from the capability of the production of aflatoxins, the productions of enzymes by like fungi have been explored. Aflatoxin B1-producing-toxigenic strains of Aspergillus flavus (A 1 ), Aspergillus parasiticus (A 2 ), Penicillium citrinum (P 1 ) and Penicillium rubrum (P 2 ) isolated from rice were grown on a defined medium with varying carbon and nitrogen sources. They were also grown on rice as sole carbon and nitrogen source for fungal growth. In an attempt to purify, the extracellular α -amylases produced were subjected to ammonium sulfate precipitation (40–90% saturation) followed by dialysis. The aflatoxin B1-producing toxigenic strains of Aspergillus flavus (A 1 ), Aspergillus parasiticus (A 2 ), Penicillium citrinum (P 1 ) and Penicillium rubrum (P 2 ) were able to produce α -amylases in both the growth medium with varying C and N sources of fungal and also in the rice medium. The most active α -amylase activity was produced by toxigenic A. flavus (A 1 ) with a value of 3.25 ± 0.15 Units and this was when ammonium sulfate was nitrogen source with starch as carbon source of fungal growth in the defined growth medium. These toxigenic fungal strains can be explored for the industrial production of α -amylases. the production and activity of α -amylases by some toxigenic aflatoxin B1-producing strains of Aspergillus and Penicillium isolated from deterioration rice. Attempts were made to purify the α -amylases.","PeriodicalId":7431,"journal":{"name":"Aflatoxin B1 Occurrence, Detection and Toxicological Effects","volume":"56 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75786021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-20DOI: 10.5772/intechopen.90403
Xing-Zi Wang
Aflatoxin B 1 (AFB 1 ) is harmful to human health, mainly resulting from its toxic effects on the liver. AFB 1 can lead to liver cell necrosis, hemorrhage, fibrosis, cirrhosis, etc. Acute AFB 1 exposure at high levels can lead to hepatitis, whereas chronic exposure can result in liver cancer. In the past decades, a series of methods and techniques for detecting AFB 1 , including enzyme-linked immunosorbent assay (ELISA), high-performance liquid chromatography (HPLC), and thin-layer chromatography (TLC), have been developed. This study reviewed the detection methods of AFB 1 and the corresponding utilization and summarizes all methods for evaluating the toxification of AFB 1 . of ssDNA/Pg-C3N4 NSs upon the transformation of fluorescence was for ratiometric fluorescence-based analytical. This method to for multiplex detection of
{"title":"A New Approach for Detection of Aflatoxin B1","authors":"Xing-Zi Wang","doi":"10.5772/intechopen.90403","DOIUrl":"https://doi.org/10.5772/intechopen.90403","url":null,"abstract":"Aflatoxin B 1 (AFB 1 ) is harmful to human health, mainly resulting from its toxic effects on the liver. AFB 1 can lead to liver cell necrosis, hemorrhage, fibrosis, cirrhosis, etc. Acute AFB 1 exposure at high levels can lead to hepatitis, whereas chronic exposure can result in liver cancer. In the past decades, a series of methods and techniques for detecting AFB 1 , including enzyme-linked immunosorbent assay (ELISA), high-performance liquid chromatography (HPLC), and thin-layer chromatography (TLC), have been developed. This study reviewed the detection methods of AFB 1 and the corresponding utilization and summarizes all methods for evaluating the toxification of AFB 1 . of ssDNA/Pg-C3N4 NSs upon the transformation of fluorescence was for ratiometric fluorescence-based analytical. This method to for multiplex detection of","PeriodicalId":7431,"journal":{"name":"Aflatoxin B1 Occurrence, Detection and Toxicological Effects","volume":"605 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77447241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-05DOI: 10.5772/intechopen.88773
J. Lalah, S. Omwoma, Dora A.O. Orony
Cancer incidences and mortality in Kenya are increasing according to recent reports and now number among the top five causes of mortality in the country. The risk factors responsible for this increase in cancer incidences are assumed to be genetic and/or environmental in nature. The environmental factors include exposure to carcinogenic contaminants such aflatoxins (AFs). However, the exact causes of the increase in cancer incidences and prevalence in many developing countries are not fully known. Aflatoxins are known contaminants produced by the common fungi Aspergillus flavus and the closely related Aspergillus parasiticus which grow as moulds in human foods. Aflatoxin B1 (AFB1) is most common in food and is 1000 times more potent when compared with benzo(a)pyrene, the most potent carcinogenic polycyclic aromatic hydrocarbon (PAH). Aflatoxins have therefore drawn a lot of interest in research from food safety and human health point of view. In this chapter, the chemistry, synthesis, identification, toxicology and potential human health risks of AFB1 in Kenya are discussed.
{"title":"Aflatoxin B1: Chemistry, Environmental and Diet Sources and Potential Exposure in Human in Kenya","authors":"J. Lalah, S. Omwoma, Dora A.O. Orony","doi":"10.5772/intechopen.88773","DOIUrl":"https://doi.org/10.5772/intechopen.88773","url":null,"abstract":"Cancer incidences and mortality in Kenya are increasing according to recent reports and now number among the top five causes of mortality in the country. The risk factors responsible for this increase in cancer incidences are assumed to be genetic and/or environmental in nature. The environmental factors include exposure to carcinogenic contaminants such aflatoxins (AFs). However, the exact causes of the increase in cancer incidences and prevalence in many developing countries are not fully known. Aflatoxins are known contaminants produced by the common fungi Aspergillus flavus and the closely related Aspergillus parasiticus which grow as moulds in human foods. Aflatoxin B1 (AFB1) is most common in food and is 1000 times more potent when compared with benzo(a)pyrene, the most potent carcinogenic polycyclic aromatic hydrocarbon (PAH). Aflatoxins have therefore drawn a lot of interest in research from food safety and human health point of view. In this chapter, the chemistry, synthesis, identification, toxicology and potential human health risks of AFB1 in Kenya are discussed.","PeriodicalId":7431,"journal":{"name":"Aflatoxin B1 Occurrence, Detection and Toxicological Effects","volume":"98 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90744685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-04DOI: 10.5772/intechopen.88666
Qin-Qin Long, Xiao-Qin Wu, Jin-Guang Yao and
Aflatoxin B1 (AFB1) is an important carcinogen for primary hepatocellular carcinoma (PHCC). However, the values of blood AFB1-DNA adducts predicting HCC risk and prognosis have not still been clear. We conducted a hospital-based case-control study, consisting of 380 patients with pathologically diagnosed PHCC and 588 controls without any evidence of liver diseases, to elucidate the associations between the amount of AFB1-DNA adducts in the peripheral blood and the risk and outcome of HCC. All subjects had not the history of hepatitis B and C virus infection. AFB1-DNA adducts were tested using enzyme-linked immunosorbent assay. Cases with PHCC featured an increasing blood amount of AFB1-DNA adducts compared with controls (2.01 ± 0.71 vs. 0.98 ± 0.63 μmol/DNA). Increasing adduct amount significantly grew the risk of PHCC [risk values, 1.82 (1.34–2.48) and 3.82 (2.71–5.40) for medium and high adduct level, respectively]. Furthermore, compared with patients with low adduct level, these with medium or high adduct level faced a higher death and tumor-recurrence risk. These results suggest that the blood AFB1-DNA adducts may act as a potential biomarker for predicting the risk and prognosis of PHCC.
{"title":"The Blood AFB1-DNA Adduct Acting as a Biomarker for Predicting the Risk and Prognosis of Primary Hepatocellular Carcinoma","authors":"Qin-Qin Long, Xiao-Qin Wu, Jin-Guang Yao and","doi":"10.5772/intechopen.88666","DOIUrl":"https://doi.org/10.5772/intechopen.88666","url":null,"abstract":"Aflatoxin B1 (AFB1) is an important carcinogen for primary hepatocellular carcinoma (PHCC). However, the values of blood AFB1-DNA adducts predicting HCC risk and prognosis have not still been clear. We conducted a hospital-based case-control study, consisting of 380 patients with pathologically diagnosed PHCC and 588 controls without any evidence of liver diseases, to elucidate the associations between the amount of AFB1-DNA adducts in the peripheral blood and the risk and outcome of HCC. All subjects had not the history of hepatitis B and C virus infection. AFB1-DNA adducts were tested using enzyme-linked immunosorbent assay. Cases with PHCC featured an increasing blood amount of AFB1-DNA adducts compared with controls (2.01 ± 0.71 vs. 0.98 ± 0.63 μmol/DNA). Increasing adduct amount significantly grew the risk of PHCC [risk values, 1.82 (1.34–2.48) and 3.82 (2.71–5.40) for medium and high adduct level, respectively]. Furthermore, compared with patients with low adduct level, these with medium or high adduct level faced a higher death and tumor-recurrence risk. These results suggest that the blood AFB1-DNA adducts may act as a potential biomarker for predicting the risk and prognosis of PHCC.","PeriodicalId":7431,"journal":{"name":"Aflatoxin B1 Occurrence, Detection and Toxicological Effects","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91490826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-17DOI: 10.5772/intechopen.89221
Qun-Ying Su
Aflatoxin B1 (AFB1) is the most common carcinogen of aflatoxin, which contaminates many agricultural products in the daily diet of humans. More than 50% of patients with developing hepatocellular carcinoma (HCC) feature AFB1 exposure due to their shared consumption of contaminated food. One of the main mechanisms of AFB1-induced liver carcinogenesis is its biological activation and its interaction with DNA to produce AFB1-E-N7-dG adduct. This product may result in the formation of DNA damage and the mutations of tumor-associated genes such as TP53 and ras. In human, several pathways involving in AFB1 detoxification, including I- and II-type detoxification, DNA repair, have been reported. This study reviewed the detoxification mechanisms of AFB1 in human as well as AFB1 occurrence and toxification. Additionally, we also discussed prevention methods for AFB1 exposure.
{"title":"The Toxification and Detoxification Mechanisms of Aflatoxin B1 in Human: An Update","authors":"Qun-Ying Su","doi":"10.5772/intechopen.89221","DOIUrl":"https://doi.org/10.5772/intechopen.89221","url":null,"abstract":"Aflatoxin B1 (AFB1) is the most common carcinogen of aflatoxin, which contaminates many agricultural products in the daily diet of humans. More than 50% of patients with developing hepatocellular carcinoma (HCC) feature AFB1 exposure due to their shared consumption of contaminated food. One of the main mechanisms of AFB1-induced liver carcinogenesis is its biological activation and its interaction with DNA to produce AFB1-E-N7-dG adduct. This product may result in the formation of DNA damage and the mutations of tumor-associated genes such as TP53 and ras. In human, several pathways involving in AFB1 detoxification, including I- and II-type detoxification, DNA repair, have been reported. This study reviewed the detoxification mechanisms of AFB1 in human as well as AFB1 occurrence and toxification. Additionally, we also discussed prevention methods for AFB1 exposure.","PeriodicalId":7431,"journal":{"name":"Aflatoxin B1 Occurrence, Detection and Toxicological Effects","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77309524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-16DOI: 10.5772/intechopen.88752
Yan-Li Deng, Xue-Min Wu, Xiao-Ying Huang, Xi-Dai Long
Our previous reports have shown that the genetic single-nucleotide polymorphisms (GSNPs) in the DNA repair gene X-ray repair cross complementing 4 (XRCC4) are involved in the carcinogenesis of hepatocellular carcinoma (HCC) induced by aflatoxin B1 (AFB1). However, the effects of GSNPs in the coding regions of XRCC4 on hepatic toxicity of AFB1 have been less investigated. We conducted a hospital-based clinic tissue samples with pathologically diagnosed HCC (n = 380) in a high AFB1 exposure area to explore the possible roles of GSNPs in the coding regions of XRCC4 in AFB1-induced HCC using liver toxicity assays. A total of 143 GSNPs were included in the present study and genotyped using the SNaPshot method, whereas the liver toxicity of AFB1 was evaluated using AFB1-DNA adducts in the tissues with HCC. In the clinicopathological samples with HCC, the average adduct amount is 2.27 (cid:1) 1.09 μ mol/mol DNA. Among 143 GSNPs of XRCC4, only rs1237462915, rs28383151, rs762419679, rs766287987, and rs3734091 significantly increased the levels of AFB1-DNA adducts. Furthermore, XRCC4 GSNPs (including rs28383151, rs766287987, and rs3734091) also increased cumulative hazard for patients with HCC. These results suggest that the liver toxicity of AFB1 may be modified by XRCC4 GSNPs.
{"title":"X-Ray Repair Cross Complementing 4 (XRCC4) Genetic Single Nucleotide Polymorphisms and the Liver Toxicity of AFB1 in Hepatocellular Carcinoma","authors":"Yan-Li Deng, Xue-Min Wu, Xiao-Ying Huang, Xi-Dai Long","doi":"10.5772/intechopen.88752","DOIUrl":"https://doi.org/10.5772/intechopen.88752","url":null,"abstract":"Our previous reports have shown that the genetic single-nucleotide polymorphisms (GSNPs) in the DNA repair gene X-ray repair cross complementing 4 (XRCC4) are involved in the carcinogenesis of hepatocellular carcinoma (HCC) induced by aflatoxin B1 (AFB1). However, the effects of GSNPs in the coding regions of XRCC4 on hepatic toxicity of AFB1 have been less investigated. We conducted a hospital-based clinic tissue samples with pathologically diagnosed HCC (n = 380) in a high AFB1 exposure area to explore the possible roles of GSNPs in the coding regions of XRCC4 in AFB1-induced HCC using liver toxicity assays. A total of 143 GSNPs were included in the present study and genotyped using the SNaPshot method, whereas the liver toxicity of AFB1 was evaluated using AFB1-DNA adducts in the tissues with HCC. In the clinicopathological samples with HCC, the average adduct amount is 2.27 (cid:1) 1.09 μ mol/mol DNA. Among 143 GSNPs of XRCC4, only rs1237462915, rs28383151, rs762419679, rs766287987, and rs3734091 significantly increased the levels of AFB1-DNA adducts. Furthermore, XRCC4 GSNPs (including rs28383151, rs766287987, and rs3734091) also increased cumulative hazard for patients with HCC. These results suggest that the liver toxicity of AFB1 may be modified by XRCC4 GSNPs.","PeriodicalId":7431,"journal":{"name":"Aflatoxin B1 Occurrence, Detection and Toxicological Effects","volume":"42 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89790938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-21DOI: 10.5772/INTECHOPEN.88775
Yuhua Shan
Aflatoxin B1 (AFB1) is the most toxic in aflatoxin family. It is well known for its involvement in hepatic carcinogenesis. Other adverse effects include immune weakness, reproduction deficiency, malnutrition, and growth impairment. The key mechanism of AFB1 carcinogenesis is supposed to be epoxidation, which produce the AFB1-8,9-epoxide (AFBO) strongly adductive to DNA molecules. Other metabolites like AFM1, AFH1, and AFL, which retain DNA adductive capability, extend its toxicity. Scientists now found that AFB1 also affected epigenetic regulation, which might shed new light into AFB1 toxicity mechanism researches. The detoxification of AFB1 has always been a hot spot in AFB1-related studies. The major methods can be categorized into physical treatment, biological treatment, chemical treatment, combination strategy, and sorbent additives. None of the methods is 100% perfect, however considering economic factors, simplicity, effectiveness, safety, and preservation of the food nutrition. This review will discuss the toxicity and toxic mechanisms of AFB1. Also, detoxification of AFB1 will be reviewed.
{"title":"The Toxic Effects of Aflatoxin B1: An Update","authors":"Yuhua Shan","doi":"10.5772/INTECHOPEN.88775","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.88775","url":null,"abstract":"Aflatoxin B1 (AFB1) is the most toxic in aflatoxin family. It is well known for its involvement in hepatic carcinogenesis. Other adverse effects include immune weakness, reproduction deficiency, malnutrition, and growth impairment. The key mechanism of AFB1 carcinogenesis is supposed to be epoxidation, which produce the AFB1-8,9-epoxide (AFBO) strongly adductive to DNA molecules. Other metabolites like AFM1, AFH1, and AFL, which retain DNA adductive capability, extend its toxicity. Scientists now found that AFB1 also affected epigenetic regulation, which might shed new light into AFB1 toxicity mechanism researches. The detoxification of AFB1 has always been a hot spot in AFB1-related studies. The major methods can be categorized into physical treatment, biological treatment, chemical treatment, combination strategy, and sorbent additives. None of the methods is 100% perfect, however considering economic factors, simplicity, effectiveness, safety, and preservation of the food nutrition. This review will discuss the toxicity and toxic mechanisms of AFB1. Also, detoxification of AFB1 will be reviewed.","PeriodicalId":7431,"journal":{"name":"Aflatoxin B1 Occurrence, Detection and Toxicological Effects","volume":"95 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89673458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-09DOI: 10.5772/intechopen.88582
N. Nleya, L. Ngoma, M. Mwanza
Aflatoxin contamination in feeds used by Bulawayo peri-urban farmers for dairy cows was assessed. Semi-intensive farming was the most common farming type practised by the farmers where the animal feeds were supplemented with mixed rations, concentrated feed, grass and brewers’ spent grains. Mixed ration was the most commonly used feed supplement. Feed analysis by high-performance liquid chromatography (HPLC) showed the presence of all four naturally occurring aflatoxins: aflatoxins B 1 , B 2 , G 1 and G 2 . Total aflatoxin concentration in the feeds ranged from 0 to 250.9 μ g/kg. Mixed ration had the highest average total aflatoxin concentration of 29.0 μ g/kg, which is above the European Union (EU) standard adopted by Zimbabwe. AFB 1 , the most potent aflatoxin was the predominant aflatoxin across all feeds with an average concentration of 9.0 μ g/kg and highest concentration of 149.6 μ g/kg in a mixed ration sample which is also above the EU 5.0 μ g/kg for lactating cows. Farm personnel responses to the questionnaire showed that most of them were not aware of aflatoxins. These findings call for stringent measures to be put in place with regard to aflatoxin testing in feeds for the dairy sector as well as educat-ing the farmers on the importance of aflatoxin monitoring feed ingredients and livestock feeds.
{"title":"Aflatoxin Occurrence in Dairy Feeds: A Case of Bulawayo, Zimbabwe","authors":"N. Nleya, L. Ngoma, M. Mwanza","doi":"10.5772/intechopen.88582","DOIUrl":"https://doi.org/10.5772/intechopen.88582","url":null,"abstract":"Aflatoxin contamination in feeds used by Bulawayo peri-urban farmers for dairy cows was assessed. Semi-intensive farming was the most common farming type practised by the farmers where the animal feeds were supplemented with mixed rations, concentrated feed, grass and brewers’ spent grains. Mixed ration was the most commonly used feed supplement. Feed analysis by high-performance liquid chromatography (HPLC) showed the presence of all four naturally occurring aflatoxins: aflatoxins B 1 , B 2 , G 1 and G 2 . Total aflatoxin concentration in the feeds ranged from 0 to 250.9 μ g/kg. Mixed ration had the highest average total aflatoxin concentration of 29.0 μ g/kg, which is above the European Union (EU) standard adopted by Zimbabwe. AFB 1 , the most potent aflatoxin was the predominant aflatoxin across all feeds with an average concentration of 9.0 μ g/kg and highest concentration of 149.6 μ g/kg in a mixed ration sample which is also above the EU 5.0 μ g/kg for lactating cows. Farm personnel responses to the questionnaire showed that most of them were not aware of aflatoxins. These findings call for stringent measures to be put in place with regard to aflatoxin testing in feeds for the dairy sector as well as educat-ing the farmers on the importance of aflatoxin monitoring feed ingredients and livestock feeds.","PeriodicalId":7431,"journal":{"name":"Aflatoxin B1 Occurrence, Detection and Toxicological Effects","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76339509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-09DOI: 10.5772/INTECHOPEN.88353
J. Li, Mengxi Liu
Aflatoxins are a class of carcinogenic mycotoxins, products of Aspergillus fungi, which are known contaminants in a large portion of the world’s food supply. Aflatoxin B1 (AFB1) is the most potent toxin, which has been strongly linked to the development of hepatocellular carcinoma (HCC), especially given coinfection with hepatitis B virus (HBV). AFB1 is catalyzed by cytochrome P450 (CYP450) into aflatoxin B1-8,9-exo-epoxide to form DNA adducts, which leads to carcinogenesis by disrupting DNA repair. AFB1-induced DNA damage is also caused by the production of excessive ROS, leading to the oxidation of DNA bases. The majority of AFB1-related to HCC carry G-to-T transversion of p53 gene. When the p53 gene is mutated, it shows a “gain of oncogenic function.” In addition, epigenetic alterations may potentially be beneficial for the treatment of HCC, because the epigenetic changes are reversible. This chapter will provide important information on the carcinogenicity of AFB1, including DNA damage checkpoint response and epigenetic alteration.
{"title":"The Carcinogenicity of Aflatoxin B1","authors":"J. Li, Mengxi Liu","doi":"10.5772/INTECHOPEN.88353","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.88353","url":null,"abstract":"Aflatoxins are a class of carcinogenic mycotoxins, products of Aspergillus fungi, which are known contaminants in a large portion of the world’s food supply. Aflatoxin B1 (AFB1) is the most potent toxin, which has been strongly linked to the development of hepatocellular carcinoma (HCC), especially given coinfection with hepatitis B virus (HBV). AFB1 is catalyzed by cytochrome P450 (CYP450) into aflatoxin B1-8,9-exo-epoxide to form DNA adducts, which leads to carcinogenesis by disrupting DNA repair. AFB1-induced DNA damage is also caused by the production of excessive ROS, leading to the oxidation of DNA bases. The majority of AFB1-related to HCC carry G-to-T transversion of p53 gene. When the p53 gene is mutated, it shows a “gain of oncogenic function.” In addition, epigenetic alterations may potentially be beneficial for the treatment of HCC, because the epigenetic changes are reversible. This chapter will provide important information on the carcinogenicity of AFB1, including DNA damage checkpoint response and epigenetic alteration.","PeriodicalId":7431,"journal":{"name":"Aflatoxin B1 Occurrence, Detection and Toxicological Effects","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73424737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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