Identification Key for Aspergillus Species Isolated from Maize and Soil of Nandi County, Kenya
Affiliation(s)
School of Biological Sciences, University of Nairobi, Nairobi, Kenya. Beatrice Wabusya Nyongesa*, Sheila Okoth, Vincent Ayugi.
School of Biological Sciences, University of Nairobi, Nairobi, Kenya. Beatrice Wabusya Nyongesa*, Sheila Okoth, Vincent Ayugi.
ABSTRACT
The aim of this study was to identify Aspergillus species isolated from maize kernels and soils of maize fields of Nandi County using macro and micro morphological characteristics. A cross sectional research design was used in the study and purposive sampling was employed to determine districts of Nandi County and sub locations where sampling was done. This study was part of a larger project whose aim was to survey aflatoxin exposure in the maize value chain. Aspergillus species were isolated from maize and soil samples using quarter strength potato dextrose agar and modified Rose Bengal agar respectively. Pure cultures of the isolates were sub cultured and transferred onto differential media; malt extract agar, czapek yeast extract agar and czapek dox agar for species identification using macro morphological characteristics. Fungal slides were prepared from pure cultures on potato dextrose agar media after three days to identify micro morphological characteristics. Based on morphological characteristics, seven sections of Aspergillus namely: Flavi, Fumigati, Nigri, Circumdati, Clavati, Nidulantes and Candidi were identified. Aspergillus section Flavi was the most predominant with 57% followed by section Nigri with 27% from maize and 58% of section Flavi followed by 26% of section Nigri from the soil across the three locations. Aspergillus sections Nidulantes and Candidi were rare and only recovered from the soil samples of Kaptumo location. All the Aspergillius flavus that formed sclerotia both from the soils or maize kernels were of the L strains. In conclusion Aspergillus section Flavi was most frequent during the isolation process and dominated with Aspergillus flavus from both the maize and soil. Morphological characteristics remain the primary tool for detection and identification of Aspergillus species. The significance for high incidence of Aspergillus section Flavi is in regard to their aflatoxin production profiles that poses a health threat to the community and it is of public health concern. Morphological characteristics as a primary tool for Aspergillus identification should be embraced and more personnel with the knowledge are required since modern and faster techniques are scarce and expensive.
The aim of this study was to identify Aspergillus species isolated from maize kernels and soils of maize fields of Nandi County using macro and micro morphological characteristics. A cross sectional research design was used in the study and purposive sampling was employed to determine districts of Nandi County and sub locations where sampling was done. This study was part of a larger project whose aim was to survey aflatoxin exposure in the maize value chain. Aspergillus species were isolated from maize and soil samples using quarter strength potato dextrose agar and modified Rose Bengal agar respectively. Pure cultures of the isolates were sub cultured and transferred onto differential media; malt extract agar, czapek yeast extract agar and czapek dox agar for species identification using macro morphological characteristics. Fungal slides were prepared from pure cultures on potato dextrose agar media after three days to identify micro morphological characteristics. Based on morphological characteristics, seven sections of Aspergillus namely: Flavi, Fumigati, Nigri, Circumdati, Clavati, Nidulantes and Candidi were identified. Aspergillus section Flavi was the most predominant with 57% followed by section Nigri with 27% from maize and 58% of section Flavi followed by 26% of section Nigri from the soil across the three locations. Aspergillus sections Nidulantes and Candidi were rare and only recovered from the soil samples of Kaptumo location. All the Aspergillius flavus that formed sclerotia both from the soils or maize kernels were of the L strains. In conclusion Aspergillus section Flavi was most frequent during the isolation process and dominated with Aspergillus flavus from both the maize and soil. Morphological characteristics remain the primary tool for detection and identification of Aspergillus species. The significance for high incidence of Aspergillus section Flavi is in regard to their aflatoxin production profiles that poses a health threat to the community and it is of public health concern. Morphological characteristics as a primary tool for Aspergillus identification should be embraced and more personnel with the knowledge are required since modern and faster techniques are scarce and expensive.
Cite this paper
Nyongesa, B. , Okoth, S. and Ayugi, V. (2015) Identification Key for Aspergillus Species Isolated from Maize and Soil of Nandi County, Kenya. Advances in Microbiology, 5, 205-229. doi: 10.4236/aim.2015.54020.
Nyongesa, B. , Okoth, S. and Ayugi, V. (2015) Identification Key for Aspergillus Species Isolated from Maize and Soil of Nandi County, Kenya. Advances in Microbiology, 5, 205-229. doi: 10.4236/aim.2015.54020.
References
[1] Ainsworth, G.C. (1976) Introduction to the History of Mycology. Cambridge University Press, Cambridge.
Alberts, A.W. (1998) Discovery, Biochemistry and Biology of Lovastatin. American Journal of Cardiology, 62, 10J-15J. [2] McClenny, N. (2005) Laboratory Detection and Identification of Aspergillus Species by Microscopic Observation and Culture: The Traditional Approach. Journal of Medical Mycology, 43, S125-S128. [3] Warris, A., Voss, A. and Verweij, P.E. (2001) Hospital Sources of Aspergillus: New Routes of Transmission. Journal Review in Microbiology, 18, 156-162. [4] Guarro, J., Gene, J. and Stchigel, A.M. (1999) Development of Fungal Taxonomy. Clinical Microbiology Reviews, 12, 454-500. [5] Bennett, J.W. (2010) An Overview of the Genus Aspergillus. In: Machida, M. and Gomi, K., Eds., Aspergillus: Molecular Biology and Genomics. [6] Klich, M.A. (2002) Identification of Common Aspergillus Species. Centraal bureau voor Schim, Utrecht. [7] Raper, K.B. and Fennel, D.I. (1965) The Genus Aspergillus. The Williams and Wilkins Company. [8] Samson, R.A., Hoekstra, E.S. and Frisvad, J.C. (2004) Introduction to Food and Airborne Fungi. 7th Edition, Centraalbureau voor Schimmelcultures, Utrecht. [9] Bennett, J.W. and Christensen, S.B. (1983) New Perspectives on Aflatoxin Biosynthesis. Advances in Applied Microbiology, 29, 53-92.
http://dx.doi.org/10.1016/S0065-2164(08)70354-X [10] Ministry of Finance and Planning Kenya (2002-2008). [11] Okoth, S., Nyongesa, B., Ayugi, V., Kang’ethe, E., Korhonen, H. and Joutsjoki, V. (2012) Toxigenic Potential of Aspergillus Species Occuring on Maize Kernels from Two Agro-Ecological Zones in Kenya. Toxins, 4, 991-1007.
http://dx.doi.org/10.3390/toxins4110991 [12] Traisat, H. (1989) Sampling, Sample Handling and Preparation in Grains and Cereals. In: Semple, R.L., Frio, A.S., Hicks, P.A. and Lozare, J.V., Eds., Mycotoxin Prevention and Control in Food Grains, UNDP/FAO Regional Network Inter-Country Cooperation on Preharvest Technology and Quality Control of Food Grains (REGNET) and the ASEAN Grain Postharvest Programme, Bankok. [13] Cotty, P.J. (1994) Comparison of Four Media for Isolation of A. flavus Group of Fungi. Mycopathologia, 125, 125-162. [14] Klich, M.A. (2002) Biogeography of Aspergillus Species in Soil and Litter. Mycologia, 94, 21-27.
http://dx.doi.org/10.2307/3761842 [15] Pitt, J.I., Hocking, A. and Glend, D. (1983) An Improved Medium for the Detection of Aspergillus flavus and A. parasiticus. Journal of Applied Bacteriology, 54, 109-114.
http://dx.doi.org/10.1111/j.1365-2672.1983.tb01307.x [16] Nelson, P.E., Tousson, T.A. and Marasas, W.F.O. (1983) Fusarium Species: An Illustrated Manual for Identification. Pennsylvania State University, University Park. [17] Pitt, J.I. and Hocking, A.D. (1997) Fungi and Food Spoilage. 2nd Edition, Blackie, London. [18] Muthomi, J.W., Njenga, L.N., Gathumbi, J.K. and Cheminingwa, N. (2009) The Occurrence of Aflatoxins in Maize and Distribution of Mycotoxin-Producing Fungi in Eastern Kenya. Plant Pathology Journal, 8, 113-119.
http://dx.doi.org/10.3923/ppj.2009.113.119 [19] Wicklow, D.T., McAlpin, C.E. and Platis, C.E. (1998) Characterization of the Aspergillus flavus Population within an Illinois Maize Field. Mycological Research, 102, 263-268.
http://dx.doi.org/10.1017/S0953756297004851 [20] McGee, D.C., Olanya, O.M., Hoyos, G.M. and Tiffany, L.H. (1996) Populations of Aspergillus flavus in the Iowa Cornfield Ecosystem in Years Not Favorable for Aflatoxin Contamination of Corn Grain. Plant Disease, 80, 742-746.
http://dx.doi.org/10.1094/PD-80-0742 [21] Surajudeen, A.A., Makun, H.A., Anjorin, S.T., Moronfoye, B., Adejo, F.O., Afolabi, O.A., Fagbayibo, G.B., et al. (2010) Fungal and Aflotoxin Contamination of Some Human Food Commodities in Nigeria. African Journal of Food Science, 4, 127-135. [22] Gao, J., Liu, Z. and Yu, J. (2007) Identification of Aspergillus Section Flavi in Maize in North Eastern China. Mycopathologia, 164, 91-95.
http://dx.doi.org/10.1007/s11046-007-9029-4 [23] Dorner, J.W., Cole, R.J. and Blankenship, P.D. (1998) Effect of Inoculum Agents on Preharvest Aflatoxin Contamination of Peanuts. Biological Control, 12, 171-176.
http://dx.doi.org/10.1006/bcon.1998.0634 [24] Horn, B.W., Greene, R.L. and Dorner, J.W. (1995) Effect of Corn and Peanut Cultivation on Soil Populations of Aspergillus flavus and A. parasiticus in Southwestern Georgia. Applied and Environmental Microbiology, 62, 2472-2475. [25] Nesci, A. and Etcheverry, M. (2002) Aspergillus Section Flavi Populations from Field Maize in Argentina. Letters in Applied Microbiology, 34, 343-348.
http://dx.doi.org/10.1046/j.1472-765X.2002.01094.x
[1] Ainsworth, G.C. (1976) Introduction to the History of Mycology. Cambridge University Press, Cambridge.
Alberts, A.W. (1998) Discovery, Biochemistry and Biology of Lovastatin. American Journal of Cardiology, 62, 10J-15J. [2] McClenny, N. (2005) Laboratory Detection and Identification of Aspergillus Species by Microscopic Observation and Culture: The Traditional Approach. Journal of Medical Mycology, 43, S125-S128. [3] Warris, A., Voss, A. and Verweij, P.E. (2001) Hospital Sources of Aspergillus: New Routes of Transmission. Journal Review in Microbiology, 18, 156-162. [4] Guarro, J., Gene, J. and Stchigel, A.M. (1999) Development of Fungal Taxonomy. Clinical Microbiology Reviews, 12, 454-500. [5] Bennett, J.W. (2010) An Overview of the Genus Aspergillus. In: Machida, M. and Gomi, K., Eds., Aspergillus: Molecular Biology and Genomics. [6] Klich, M.A. (2002) Identification of Common Aspergillus Species. Centraal bureau voor Schim, Utrecht. [7] Raper, K.B. and Fennel, D.I. (1965) The Genus Aspergillus. The Williams and Wilkins Company. [8] Samson, R.A., Hoekstra, E.S. and Frisvad, J.C. (2004) Introduction to Food and Airborne Fungi. 7th Edition, Centraalbureau voor Schimmelcultures, Utrecht. [9] Bennett, J.W. and Christensen, S.B. (1983) New Perspectives on Aflatoxin Biosynthesis. Advances in Applied Microbiology, 29, 53-92.
http://dx.doi.org/10.1016/S0065-2164(08)70354-X [10] Ministry of Finance and Planning Kenya (2002-2008). [11] Okoth, S., Nyongesa, B., Ayugi, V., Kang’ethe, E., Korhonen, H. and Joutsjoki, V. (2012) Toxigenic Potential of Aspergillus Species Occuring on Maize Kernels from Two Agro-Ecological Zones in Kenya. Toxins, 4, 991-1007.
http://dx.doi.org/10.3390/toxins4110991 [12] Traisat, H. (1989) Sampling, Sample Handling and Preparation in Grains and Cereals. In: Semple, R.L., Frio, A.S., Hicks, P.A. and Lozare, J.V., Eds., Mycotoxin Prevention and Control in Food Grains, UNDP/FAO Regional Network Inter-Country Cooperation on Preharvest Technology and Quality Control of Food Grains (REGNET) and the ASEAN Grain Postharvest Programme, Bankok. [13] Cotty, P.J. (1994) Comparison of Four Media for Isolation of A. flavus Group of Fungi. Mycopathologia, 125, 125-162. [14] Klich, M.A. (2002) Biogeography of Aspergillus Species in Soil and Litter. Mycologia, 94, 21-27.
http://dx.doi.org/10.2307/3761842 [15] Pitt, J.I., Hocking, A. and Glend, D. (1983) An Improved Medium for the Detection of Aspergillus flavus and A. parasiticus. Journal of Applied Bacteriology, 54, 109-114.
http://dx.doi.org/10.1111/j.1365-2672.1983.tb01307.x [16] Nelson, P.E., Tousson, T.A. and Marasas, W.F.O. (1983) Fusarium Species: An Illustrated Manual for Identification. Pennsylvania State University, University Park. [17] Pitt, J.I. and Hocking, A.D. (1997) Fungi and Food Spoilage. 2nd Edition, Blackie, London. [18] Muthomi, J.W., Njenga, L.N., Gathumbi, J.K. and Cheminingwa, N. (2009) The Occurrence of Aflatoxins in Maize and Distribution of Mycotoxin-Producing Fungi in Eastern Kenya. Plant Pathology Journal, 8, 113-119.
http://dx.doi.org/10.3923/ppj.2009.113.119 [19] Wicklow, D.T., McAlpin, C.E. and Platis, C.E. (1998) Characterization of the Aspergillus flavus Population within an Illinois Maize Field. Mycological Research, 102, 263-268.
http://dx.doi.org/10.1017/S0953756297004851 [20] McGee, D.C., Olanya, O.M., Hoyos, G.M. and Tiffany, L.H. (1996) Populations of Aspergillus flavus in the Iowa Cornfield Ecosystem in Years Not Favorable for Aflatoxin Contamination of Corn Grain. Plant Disease, 80, 742-746.
http://dx.doi.org/10.1094/PD-80-0742 [21] Surajudeen, A.A., Makun, H.A., Anjorin, S.T., Moronfoye, B., Adejo, F.O., Afolabi, O.A., Fagbayibo, G.B., et al. (2010) Fungal and Aflotoxin Contamination of Some Human Food Commodities in Nigeria. African Journal of Food Science, 4, 127-135. [22] Gao, J., Liu, Z. and Yu, J. (2007) Identification of Aspergillus Section Flavi in Maize in North Eastern China. Mycopathologia, 164, 91-95.
http://dx.doi.org/10.1007/s11046-007-9029-4 [23] Dorner, J.W., Cole, R.J. and Blankenship, P.D. (1998) Effect of Inoculum Agents on Preharvest Aflatoxin Contamination of Peanuts. Biological Control, 12, 171-176.
http://dx.doi.org/10.1006/bcon.1998.0634 [24] Horn, B.W., Greene, R.L. and Dorner, J.W. (1995) Effect of Corn and Peanut Cultivation on Soil Populations of Aspergillus flavus and A. parasiticus in Southwestern Georgia. Applied and Environmental Microbiology, 62, 2472-2475. [25] Nesci, A. and Etcheverry, M. (2002) Aspergillus Section Flavi Populations from Field Maize in Argentina. Letters in Applied Microbiology, 34, 343-348.
http://dx.doi.org/10.1046/j.1472-765X.2002.01094.x