Aspergillus species and aflatoxins production are more prevalent during times of high heat and drought. In South Africa, there is frequent occurrence of drought as a result of climate change. The aim of this study was...Aspergillus species and aflatoxins production are more prevalent during times of high heat and drought. In South Africa, there is frequent occurrence of drought as a result of climate change. The aim of this study was to investigate the biodiversity and distribution of Aspergillus species with their corresponding toxins in maize from main maize producing regions of South Africa;[Western Regions (WR) and Eastern Regions (ER)]. One hundred and twenty-three (64 from WR and 59 from ER) maize samples from the two agro-climatic regions in South Africa were analyzed using cultural, molecular and analytical methods. Across agro-climatic regions, Aspergillus species contaminated about 62% of the maize samples, while Aspergillus flavus was the most prevalent (47.15%) followed by Aspergillus fumigatus (4.69%) while the least was Aspergillus parasiticus (0.81%). The Western Regions showed a higher distribution of varieties of Aspergillus species compared to the Eastern Regions. Aflatoxins contaminated only 27.64% of the maize samples with a mean total aflatoxin concentration of 2.40 μg/kg which is below the South Africa’s set standard for total aflatoxin in food (5 μg/kg). About 10.57% of the samples produce aflatoxins above the 5 μg/kg permissible limit for total aflatoxin in foods. The ratio of toxigenic to atoxigenic strains of Aspergillus flavus was generally low in all the regions of South Africa. This study could aid policy makers to make informed decisions in developing remediation strategies for Aspergillus mycotoxins.展开更多
Aim:Previous studies have demonstrated the racial disparities of new incidence and mortality rate of hepatocellular carcinoma(HCC)patients,but the racial differences in the tumor characteristics causing these disparit...Aim:Previous studies have demonstrated the racial disparities of new incidence and mortality rate of hepatocellular carcinoma(HCC)patients,but the racial differences in the tumor characteristics causing these disparities remain unclear.Methods:We collected genomic mutation profile of 589 HCC patients,including Asian-Korea(n=231),Asian TCGA(n=156),White-TCGA(n=176),and Black-TCGA(n=16).We applied a non-negative factorized matrix algorithm to decipher the mutational signatures of HCC patients,compared racial differences of mutational signature,performed molecular subtyping analysis of HCC patients based on their composition of mutational signatures,and evaluated their influence on clinical outcome.Results:Asian patients showed a significantly higher level of SBS96F-aristolochic acid exposure signature related to the widespread usage of Chinese herbs in East Asia,and they also showed higher SBS96B-MMR at T>C mutations but lower SBS96D-MMR at C>T mutations than White patients,suggesting the heterogeneous mechanisms related to defective DNA mismatch repair across races.Asian-Korea patients showed a significantly higher SBS96C-tobacco chewing and aflatoxin exposure than the other three populations,indicating the higher levels of aflatoxin contamination in food and environment in this area.The SBS96G-Unclear signature was also observed to be significantly higher in Asian-Korea patients,and their dominated subgroup patients showed better prognosis for both disease-free and overall survival probability.Conclusion:Our study found racial differences of mutational signatures to be associated with differences in diverse genetic backgrounds and environmental factors,which might help guide the personalized treatment of HCC patients.展开更多
文摘Aspergillus species and aflatoxins production are more prevalent during times of high heat and drought. In South Africa, there is frequent occurrence of drought as a result of climate change. The aim of this study was to investigate the biodiversity and distribution of Aspergillus species with their corresponding toxins in maize from main maize producing regions of South Africa;[Western Regions (WR) and Eastern Regions (ER)]. One hundred and twenty-three (64 from WR and 59 from ER) maize samples from the two agro-climatic regions in South Africa were analyzed using cultural, molecular and analytical methods. Across agro-climatic regions, Aspergillus species contaminated about 62% of the maize samples, while Aspergillus flavus was the most prevalent (47.15%) followed by Aspergillus fumigatus (4.69%) while the least was Aspergillus parasiticus (0.81%). The Western Regions showed a higher distribution of varieties of Aspergillus species compared to the Eastern Regions. Aflatoxins contaminated only 27.64% of the maize samples with a mean total aflatoxin concentration of 2.40 μg/kg which is below the South Africa’s set standard for total aflatoxin in food (5 μg/kg). About 10.57% of the samples produce aflatoxins above the 5 μg/kg permissible limit for total aflatoxin in foods. The ratio of toxigenic to atoxigenic strains of Aspergillus flavus was generally low in all the regions of South Africa. This study could aid policy makers to make informed decisions in developing remediation strategies for Aspergillus mycotoxins.
基金supported by supported by grants from the Hong Kong Research Grant Council(RGC)including Collaborative Research Funds(C7065-18GF and C7026-18GF)Theme-based Research Scheme(T12-704/16-R)+1 种基金Shenzhen Science and Technology programs(KQTD20180411185028798)Shenzhen Fundamental Research Program(JCYJ20180508153249223)。
文摘Aim:Previous studies have demonstrated the racial disparities of new incidence and mortality rate of hepatocellular carcinoma(HCC)patients,but the racial differences in the tumor characteristics causing these disparities remain unclear.Methods:We collected genomic mutation profile of 589 HCC patients,including Asian-Korea(n=231),Asian TCGA(n=156),White-TCGA(n=176),and Black-TCGA(n=16).We applied a non-negative factorized matrix algorithm to decipher the mutational signatures of HCC patients,compared racial differences of mutational signature,performed molecular subtyping analysis of HCC patients based on their composition of mutational signatures,and evaluated their influence on clinical outcome.Results:Asian patients showed a significantly higher level of SBS96F-aristolochic acid exposure signature related to the widespread usage of Chinese herbs in East Asia,and they also showed higher SBS96B-MMR at T>C mutations but lower SBS96D-MMR at C>T mutations than White patients,suggesting the heterogeneous mechanisms related to defective DNA mismatch repair across races.Asian-Korea patients showed a significantly higher SBS96C-tobacco chewing and aflatoxin exposure than the other three populations,indicating the higher levels of aflatoxin contamination in food and environment in this area.The SBS96G-Unclear signature was also observed to be significantly higher in Asian-Korea patients,and their dominated subgroup patients showed better prognosis for both disease-free and overall survival probability.Conclusion:Our study found racial differences of mutational signatures to be associated with differences in diverse genetic backgrounds and environmental factors,which might help guide the personalized treatment of HCC patients.
