African Journals On-line
African Journal of Biotechnology

Volume 2 Number 11 November 2003
ABSTRACTS

Harmonizing the agricultural biotechnology debate for the benefit of African farmers

Segenet Kelemu¹*, George Mahuku¹, Martin Fregene¹, Douglas Pachico¹, Nancy Johnson¹, Lee Calvert¹, Idupulapati Rao¹, Robin Buruchara², Tilahun Amede³, Paul Kimani⁴, Roger Kirkby², Susan Kaaria², Kwasi Ampofo⁵

¹Centro Internacional de Agricultura Tropical (CIAT), Cali, Colombia.

²CIAT, c/o Kawanda Agricultural Research Institute, Kampala, Uganda.

³African Highland Initiative (AHI), c/o CIAT, Addis Ababa, Ethiopia.

⁴Department of Crop Science, College of Agriculture and Veterinary Sciences, University of Nairobi, Kenya.

⁵Agricultural Technology Development and Transfer Project, ISAR/CIAT/USAID, Kigali, Rwanda.

*Corresponding author. Phone: (57-2) 4450-139. Fax: (57-2) 4450-073. E-mail: [email protected]. 

Abstract

The intense debate over agricultural biotechnology is at once fascinating, confusing and disappointing. It is complicated by issues of ethical, moral, socio-economic, political, philosophical and scientific import. Its vocal champions exaggerate their claims of biotechnology as saviour of the poor and hungry, while, equally loudly, its opponents declare it as the doomsday devil of agriculture. Sandwiched between these two camps is the rest of the public, either absorbed or indifferent. Biotechnology issues specific to the African public must include crop and animal productivity, food security, alleviation of poverty and gender equity, and must exclude political considerations. Food and its availability are basic human rights issues—for people without food, everything else is insignificant. Although we should discuss and challenge new technologies and their products, bringing the agricultural biotechnology debate into food aid for Africa where millions are faced with life-or-death situations is irresponsible. Agricultural biotechnology promises the impoverished African a means to improve food security and reduce pressures on the environment, provided the perceived risks associated with the technology are addressed. This paper attempts to harmonize the debate, and to examine the potential benefits and risks that agricultural biotechnology brings to African farmers.

Key words: Agriculture, biotechnology, biotechnology debate, biotechnology and Africa, biotechnology issues, food security, poverty alleviation. 

Determination of effective nodulation in early juvenile soybean plants for genetic and biotechnology studies

E. T. Gwata¹*, D. S. Wofford¹, K. J. Boote¹, and H. Mushoriwa²

¹Department of Agronomy, University of Florida, P. O. Box 110300, Gainesville, FL – 32611 – 0300, USA.

²Crop Breeding Institute, P. O. Box CY 550, Causeway, Harare, Zimbabwe.

*Correspondence author. E-mail: [email protected]. 

Abstract 

Symbiotic fixation of atmospheric nitrogen (N₂) is a complex physiological process influenced by the interaction of genetic elements in the higher plant species and rhizobia. No standardized, efficient method is available to critically examine the effect of altering the genetic elements in either component by selection and/or genetic engineering. At planting, seeds of a tropical (‘TGX-4E’) and non-tropical (‘Soma’) soybean cultivar were inoculated individually in sand-filled Conetainers® in a greenhouse with each of two strains within two rhizobial types (Bradyrhizobium japonicum and cowpea). Six weeks after inoculation, each plant was classified into one of two categories; vigorous plant with dark green leaves indicating effective nodulation and N₂-fixation (+), and stunted plant with chlorotic yellow leaves indicating ineffective nodulation and no N₂-fixation (-). The results indicated that this non-destructive method could be used to identify major genetic differences in the soybean and inoculant. Therefore, this method could be used to rapidly identify genetic segregants resulting from selection in plant breeding programs and/or genetic engineering.

Key words: effective nodulation, rhizobia, tropical soybean type, symbiosis.

In vitro multiplication of the semi-arid forest tree, Balanites aegyptiaca (l.) Del.

Mansor Ndoye¹, Ismaïla Diallo² and Yaye Kène Gassama/Dia¹

¹Laboratoire de biotechnologies, Département de Biologie Végétale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop Dakar, B.P. 5005, Dakar, Sénégal.

²ISRA-DRPF, Route des Pères Maristes, B.P. 2312, Dakar, Sénégal.

*Corresponding author. E-mail: [email protected].  Tel: 5331084.  Fax: (221) 824 63 18.

Abstract 

Procedures were developed for micropropagation of Balanites aegyptiaca using axillary bud explants obtained from mature trees. Cultures were established in Murashige and Skoog (MS) medium supplemented with 2.5 mg/l 6-benzylaminopurine (BAP) and 0.1 mg/l naphthalene acetic acid (NAA). The effects of kinetin on shoot growth and proliferation in vitro was also investigated. Results show that shoot multiplication required 2.5 mg/l of BAP. Shoot length was significantly affected by the presence of BAP or 6-furfurylaminopurine (Kin). Rooting of shoots in vitro was achieved on MS medium containing 20 mg/l of the auxin, indolebutyric acid (IBA). Rooted shoots acclimated and were successfully transferred into soil, with 48% of the plantlets surviving.

Key words: Balanites aegyptiaca, micropropagation, rooting.

Comparative efficacy of microbial and chemical insecticides on four major lepidopterous pests of cotton and their (insect) natural enemies

T. A. Fadare* and N. A. Amusa

Institute of Agricultural Research and Training, Obafemi Awolowo University, P.M.B. 5029, Moor Plantation, Ibadan, Nigeria.

*Corresponding author. E-mail: [email protected]. 

Abstract 

Three microbial (biotrol, dipel and thuricide) and three chemical insecticides (monocrotophos, endosulfan and carbaryl) were compared for efficacy on four major lepidopterans and their natural enemies in replicated field trials at Moor Plantation, Ibadan. Thuricide was evaluated at different combinations with monocrotophos in a second trial. The results showed that the microbials caused the mortalities of destructive bollworms and leafroller but allowed the survival of their natural enemies. The chemicals on the other hand caused mortalities of both destructive and useful species. Both groups of insecticides enhanced seed cotton yields. Application of thuricide followed by monocrotophos was better than other combinations evaluated.

Key words: microbial insecticides, Bacillus thuringiensis, cotton.

Solanum cultivar responses to arbuscular mycorrhizal fungi: growth and mineral status

Tahir Abdoulaye DIOP^1,2*, Tatiana KRASOVA-WADE^1,2, Alioune DIALLO^1,2, Meïssa DIOUF³, Mamadou GUEYE²

¹Département de Biologie Végétale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, BP 5005, Sénégal.

²Laboratoire de Microbiologie des Sols, Centre de Recherches ISRA/IRD, BP 1386, Dakar Sénégal.

³Institut Sénégalais de Recherches Agricoles/CDH, BP 3120 – Dakar, Sénégal.

*Corresponding author. E.mail: [email protected]. 

Abstract 

A greenhouse experiment was carried out in a sandy soil with a low available phosphorus to evaluate responsiveness of four Solanum aethiopicum cultivars to indigenous arbuscular mycorrhizal fungi. Results showed clear interaction between genetic variability of cultivars and fungal isolates on shoot biomass and on mineral status. Arbuscular mycorrhizal fungi can be ranked as Glomus aggregatum > Glomus mosseae > Glomus versiforme for improving yield as well as nitrogen, phosphorus, and potassium acquisition of Solanum cultivars.

Key words: Arbuscular mycorrhizal fungi, Solanum aethiopicum, sterile soil, relative mycorrhizal dependency.

Farmer’s knowledge and perception of horticultural insect pest problems in southwestern Nigeria

Banjo, A.D. ¹, Lawal, O.A. ¹*, Fapojuwo, O.E. ² and Songonuga, E. A. ¹

¹Department of Biological Sciences, Olabisi Onabanjo University, P.M.B. 2002, Ago-Iwoye, Ogun-State, Nigeria.

²Department of Extention and Rural Sociology, Olabisi Onabanjo University, P.M.B. 2002, Ago-Iwoye, Ogun-State, Nigeria.

*Corresponding author. E-mail: [email protected],  [email protected]. 

Abstract 

This survey was carried out in three states of southwestern Nigeria (Ogun, Oyo and Lagos states) on farmer’s perception of horticultural insect pest problems. The survey was conducted between August 2002 and January 2003. A large number of the farmers were above 25 years old (91%). They were predominantly male (73%) and about 76% were married. Some farmers cultivate both tree and vegetables (36.5%) while a few of them plant trees, vegetable and ornamentals together (5.4%). Whilst 89% were aware of insect pest problems, only 35% used chemical treatment even though about 79% thought that pest damage ranged from mild to severe. Majority of the farmers adopt diverse number of traditional methods in pest control.

Key words: Farmers, pests, horticultural crops, vegetable, control.

Transformation kinetics of mixed polymeric substrates under transitory conditions by Aspergillus niger

Lacina Coulibaly ¹*and Spiros N. Agathos²

¹Laboratoire d’Environnement et de Biologie Aquatique, UFR-Sciences et Gestion de l’Environnement, Université d’Abobo-Adjamé 02 BP 801 Abidjan 02, Côte d’Ivoire.

²Unit of Bioengineering, Catholic University of Louvain Place Croix du Sud 2 Bte 19, 1348 Louvain-la-Neuve, Belgium.

*Corresponding author. E-mail: [email protected].  Tel: 07497153.

Abstract 

A mixture of polymeric substrates (simulating a complex wastewater) was transformed under sewer conditions and aerobiosis by Aspergillus niger in a tanks-in-series reactor at a hydraulic retention time of 14 h. Starch was totally removed after 7 h of incubation. Removal of the protein portion with a molecular weight larger than 2 kDa followed the starch removal and the total proteins were the latest to be removed. Alkaline phosphatase, leucine aminopeptidase, valine aminopeptidase, a-bglucosidase and a-mannosidase were abundantly secreted in the growth medium. This research is the first report on mixed polymeric substrate biodegradation under sewer condition by A. niger, and could be considered as an open window on fungal biomass valorisation in wastewater treatment.

Keywords: Polysaccharide, wastewater, starch, bovine serum albumin, macromolecules, tank-in-series reactor, enzyme.

Production and regulation of lignin degrading enzymes from Lentinus squarrosulus (mont.) Singer and Psathyrella atroumbonata Pegler

Wuyep. P. A ¹ Khan, A. U¹, and Nok, A. J. ²

¹Department of Biological Sciences, Ahmadu Bello University, Zaria, Nigeria.

²Department of Biochemistry, Ahmadu Bello University, Zaria, Nigeria.

*Corresponding author. E-mail: [email protected]. 

Abstract 

The influence of metal ions on the production and regulation of ligninase and mycelia extension of two type Basidiomycetes (Lentinus squarrosulus and Psathyrella atroumbonata) cultivated on lignocellulose waste was investigated. Mn2+ and Ca2+ ions stimulated growth of both fungi and mycelia extension significantly.  Ligninase production increased two to twelve fold under the influence of Mn2+ and Ca2+ ions at concentrations of 20 to 80 mM.  Mg2+ and K+ ions did not stimulate growth and extension of fungal mycelia, rather fungal cultures became deactivated after six days. The importance of mycelia extension and enhanced enzyme production has biotechnological applications in wood and pulp, textile and tanning, as well as in oil industries.

Key words: Basidiomycetes, Lentinus squarrosulus, Psathyrella atroumbonata, ligninase, cofactors.

Safety and protective effect of Lactobacillus acidophilus and Lactobacillus casei used as probiotic agent in vivo

Oyetayo, V.O*, Adetuyi, F.C. and Akinyosoye, F.A.

Department of Microbiology, Federal University of Technology, P.M.B. 704, Akure, Nigeria.

*Corresponding author. E-mail: [email protected]. 

Abstract 

The protective effect of Lactobacillus acidophilus and Lactobacillus casei, isolated from fresh cow milk, was studied in vivo. Toxicological data of rat serum revealed that the Lactobacillus isolates had liver improvement functions. Serum alanine aminotransferase (ALT) activities of the rats dosed with Lactobacillus isolates alone were lower (15.50 and 18.27 iu/l) than the control. There was a reduction in the count of enterobacteria in rats dosed with L. casei after 3 days of feeding trials. Protection of the gastrointestinal tract (GIT) by these isolates was also observed. Histopathological data confirmed partial protection of the GIT in rats dosed with Lactobacillus isolates and simultaneously infected with Escherichia coli. L. casei was generally observed to have a better effect than L. acidophilus in terms of liver function improvement, anticholesterolaemic effect, and reduction of enterobacteria in the GIT.  

Key words: Probiotic, protection, Lactobacillus.

Effects of microwave heating on the thermal states of biological tissues

Nabil T. M. El-dabe, Mona A. A. Mohamed and Asma. F. El-Sayed

Math. Department, Faculty of Education, Ain Shams University, Heliopolis, Cairo, Egypt.

*Correspondence author. E-mail: [email protected]. 

Abstract 

A mathematical analysis of microwave heating equations in one-dimensional multi-layer model has been discussed. Maxwell's equations and transient bioheat transfer equation were numerically calculated by using finite difference method to predict the effects of thermal physical properties on the transient temperature of biological tissues. This prediction of the temperature evolution in biological bodies can be used as an effective tool for thermal diagnostics in medical practices.

Key words: Microwave heating, Maxwell's equations, bioheat, multi layer.

Some genetic characteristics of sabin-like poliovirus isolated from acute flaccid paralysis cases in Nigeria

Festus Doyin Adu¹*, Jane Iber², Tekena Harry³, Cara Burns², Oluseyi Oyedele¹, Johnson Adekunle Adeniji ¹, Mubarak Ossei-Kwasi ⁴ David  Kilpatrick² Oyewale Tomori⁵ and Olen Kew²

¹Department of Virology, College of Medicine, University of Ibadan, Nigeria.

²Division of Molecular Virology, Center for Disease Control and Prevention, Atlanta Georgia, USA.

³Dept of Immunology, University of Maiduguri  Teaching Hospital, Maiduguri, Nigeria.

⁴Noguchi Memorial Institute for Medical Research Legon Ghana.

⁵WHO Regional Office Harare Zimbabwe

*Corresponding author. Email: [email protected],  [email protected]. 

Abstract 

A total of 34 sabin strains of the poliovirus isolated from 22 children with 60-day follow-up residual acute flaccid paralysis (AFP) were genetically characterized and screened for any form of recombination. Sequence analysis of the 906-nucleotide capsid showed that all the isolates were similar to their original sabin serotypes, however two of the viruses had drifted in their 3D noncapsid regions toward a sabin-sabin and sabin-nonpolio entero combination. Routine immunization in Nigeria is low and in spite of the increase in the frequency of supplemental immunizations, a lot of children are still inadequately immunized, which may be the reason for our observation in this study.  Although we are not dealing with a case of circulating vaccine derived poliovirus (cVDPV) yet, if the above condition persists, the advent of cVDVP may not be too far. There is therefore the need to maintain a high quality mass immunization and sustained routine immunization.   

Key words: Poliovirus, sequence, crossover, non polio enterovirus, recombination, genome, Sabin-like, vaccine, Nigeria.

Comparison of ivermectin and thiabendazole in the treatment of uncomplicated human Strongyloides stercoralis infection

AA Adenusi¹*, AO Oke¹ and AO Adenusi²

¹Department of Biological Sciences, Olabisi Onabanjo University, P.M.B. 2002, Ago-Iwoye, Ogun State, Nigeria.

²Primary Health Care Unit, Yewa South Local Government, Ilaro, Ogun State, Nigeria.

*Author for correspondence, E-mail: [email protected]. 

Abstract 

Ivermectin is the drug of choice in the treatment of onchocerciasis, and has been proven to be highly effective against Strongyloides stercoralis. This study compares ivermectin’s efficacy and safety with that of thiabendazole, an established drug of choice for strongyloidiasis, in 252 confirmed cases of uncomplicated human intestinal strongyloidiasis. Subjects were administered orally with ivermectin (200 mg/kg) in a single dose or thiabendazole, 25 mg/kg, twice daily (50mg/kg/day) for 3 consecutive days. Stools were parasitologically examined 7, 21 and 30 days after treatment. Only 18 of 113 and 22 of 103 ivermectin- and thiabendazole-treated subjects, respectively, had stools positive for larvae 30 days post-treatment. This indicates parasitological cure rates of 84.07% and 78.64% for ivermectin and thiabendazole, respectively. Ivermectin was not significantly more effective than thiabendazole (P < 0.05). There was considerable reduction in parasite output in parasitologically uncured subjects with mean of 81% in ivermectin-treated and 75% in thiabendazole-treated groups, respectively. Clinical adverse reactions were mild and transient in subjects treated with ivermectin, while they varied from mild to severe in those treated with thiabendazole. Single-dose ivermectin provides efficacy comparable with standard, multiple-dose thiabendazole, with a much reduced incidence of adverse effects and consequently better patient compliance.

Key words: Ivermectin, thiabendazole, Strongyloides stercoralis, strongyloidiasis.

Relative prevalence of the human hookworm species, Necator americanus and Ancylostoma duodenale in an urban community in Ogun State, Nigeria

AA Adenusi¹* and EOA Ogunyomi²†

¹Department of Biological Sciences, Olabisi Onabanjo University, P.M.B. 2002, Ago-Iwoye, Ogun State, Nigeria.

²Primary Health Care Department, Sagamu Local Government Secretariat, Ogun State. Nigeria.

*Corresponding author. E-mail: [email protected]. 

†Recent address: Primary Health Care Centre, Ilishan, Ogun State. Nigeria.

Abstract 

In order to estimate the proportion of hookworm infections represented by Necator americanus and Ancylostoma duodenale, the 2 major species of human hookworms in Nigeria, stool samples from 1253 hookworm-positive schoolchildren were cultured to the third-stage (L3), filariform larvae, using the Harada-Mori test-tube method. N. americanus larvae were recovered from a total of 1177 (93.9%) coprocultures while A. duodenale larvae were recovered from a total of 274 (21.9%) stool cultures. 58.2% of the hookworm infections were due solely to N. americanus, 6.1% solely to A. duodenale and 25.8% were mixed infections with both species. In all mixed infections, much higher number of N. americanus larvae were recorded compared with those of A. duodenale.

Key words: Hookworm species, Necator americanus, Ancylostoma duodenale, filariform larvae.

In vitro activity of commercial formulation and active principle of trypanocidal drugs against blooststreams forms of Trypanosoma brucei gambiense

Clarisse Lekane Likeufack¹, Lisette Kohagne Tongue¹, and Philippe Truc^1,2 *

¹Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Department of Research and Control of Human African Trypanosomiasis, BP 288, Yaounde, Cameroon.

²Institut de Recherche pour le Développement, IRD, Research Unit 35 BP 1857, Yaounde, Cameroon.

*Corresponding author. Mailing address: OCEAC, BP 288, Yaounde, Cameroon. Phone: + 237 984 60 57. Fax: + 237 220 18 54. E-mail: [email protected]. 

Abstract 

The in vitro trypanocidal activities of 4 commercial formulations Ornidyl®, Pentamidine isethionate®, Germanin® and Lampit® and their corresponding active principles (Dl-difluoromethylornithine, pentamidine isethionate, suramine and 5-nitrofuran) were compared against Trypanosoma brucei gambiense. Differences of minimum inhibitory concentration (MIC) were observed between Ornidyl® and Dl-difluoromethylornithine and between Lampit® and 5-nitrofuran. For RO 15 strain and the comparison of Ornidyl®/ DFMO, the MIC when using the commercial drug was more than twice the MIC value obtained with the active principle. For all 3 trypanosome strains, MICs were identical for Lampit® and 5-nitrofuran but the MIC with the commercial formulation was twice the MIC obtained with the active principle. The active principles, rather than commercial formulations, should be used for standardization of in vitro assay protocols.

Key words: In vitro activity, trypanocidal drugs, commercial formulations, Trypanosoma brucei gambiense.