African Journals On-line
African Journal of Biotechnology

Volume 2, Number 3, March 2003
Abstracts

Molecular phylogeny of Fusarium species by AFLP fingerprint

Mohmed A. Abdel-Satar¹, Mohmed. S. Khalil², I. N. Mohmed¹, Kamel A. Abd-Elsalam^2,3*, and Joseph A. Verreet³

¹Suez Canal University, Faculty of Agriculture, Ismailia, Egypt.

²Agricultural Research Center, Plant Pathology Research Institute, Giza, Egypt.

³Christian Albrechts Universität zu Kiel, Institut für Phytopathologie, Kiel, Germany.

*Corresponding author; Phone: (49 431) 880 2993; fax: (49 431) 880 1583; e-mail: [email protected]

Abstract: The high-resolution genotyping method of amplified fragment length polymorphism (AFLP) analysis was used to study the genetic relationships within and between natural populations of five Fusarium spp. AFLP templates were prepared by the digestion of Fusarium DNA with EcoRI and MseI restriction endonucleases and subsequent ligation of corresponding site-specific adapters. An average of 44 loci was assayed simultaneously with each primer pair and DNA markers in the range 100 to 500 bp were considered for analysis. A total of 80 AFLP polymorphic markers were obtained using four primer combinations, with an average of 20 polymorphic markers observed per primer pair. UPGMA analyses indicated 5 distinct clusters at the phenon line of 30% on the genetic similarity scale corresponding to the 5 taxa. The similarity percent of each group oscillated between 87 and 97%. The phenetic dendrogram generated by UPGMA as well as principal coordinate analysis (PCA) grouped all of the Fusarium spp. isolates into five major clusters. No clear trend was detected between clustering in the AFLP dendrogram and geographic origin, host genotype of the tested isolates with a few exceptions. The results of the present study provide evidence of the high discriminatory power of AFLP analysis, suggesting the possible applicability of this method to the molecular characterization of Fusarium.

Key words: AFLP, Fusarium, molecular phylogeny, selective amplification.

Biodeterioration of the African star apple (Chrysophylum albidum) in storage and the effect on its food value

N. A. Amusa*, O.A. Ashaye and M. O. Oladapo

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

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

Abstract: The biodeterioration of the African star apple fruits in storage was investigated at Ibadan, southwestern Nigeria. Eight fungal isolates were found associated with the deteriorating fruits. The fungi are Botryodiplodia theobromae, Rhizopus stolonifer, Aspergillus niger, A. tamarii, A. flavus, Fusarium spp, Penicilium spp and Trichoderma spp. All the fungal isolates were pathogenic on the star apple fruits with the exception of Trichoderma spp. The African star apple fruits stored for up to 5 days were associated with severe fungal infections and had significantly reduced crude protein, crude fat and moisture content while dry matter, potassium, calcium and sodium increased compared to the freshly harvested fruits.

Key words: Chrysophilum albidum, biodeterioration, fungal pathogens, storage.

Production of alkaline protease by Teredinobacter turnirae cells immobilized in Ca-alginate beads

Usama Beshay

Bioprocess Development Dept., Genetic Engineering and Biotechnology Research Institute (GEBRI), Mubarak City for Scientific Research and Technology Applications, New Borg El-Arab, Alexandria, Egypt. Tel: +2-03-4593420, fax: +2-03-4593423, e-mail: [email protected]

Abstract: The conditions for immobilizing the new alkaline protease-producing bacteria strain Teredinobacter turnirae by entrapment in calcium alginate gel were investigated. The influence of alginate concentration (20, 25 and 30 g/l) and initial cell loading (ICL) on enzyme production were studied. The production of alkaline protease improved significantly with increasing alginate concentration and reached a maximum enzyme yield of 8000 U/ml at 25 g/l alginate concentration. This was about 176.8% higher than that obtained by free cells (2890 U/ml). The immobilized cells produced alkaline protease consistently over 5 repeated cycles and reached a maximal value of 9000 U/ml on the third cycle. This was 311.4% (3.11-fold) as compared with the control (free cells). Simple mass balance analysis was applied to describe the growth and the protease production behaviour of both fractions the cells in free form and the entrapped in Ca-alginate beads. Scanning electron microscope studies indicated the internal distribution pattern of the cells encapsulated in Ca-alginate beads. The results presented in this paper show the potential for using immobilized T. turnirae cells in Ca-alginate for the production of a novel alkaline protease.

Key words: Alkaline protease, Ca-alginate, immobilization, Teredinobacter turnirae, repeated batch.

A capillary electrophoretic method for isolation and characterization of grape xylem proteins

Ashok K. Jain* and Sheikh M. Basha

Plant Biotechnology Lab., Center for Viticulture and Small Fruit Research, Florida A&M University, Tallahassee, FL 32307, USA.

*Corresponding Author; E-mail: [email protected],  tel: (850) 561-2219, fax: (850) 599-3119

Abstract: European (Vitis vinifera) and American (Vitis labrusca) grape species succumb to a bacterial disease known as Pierce’s Disease (PD). In contrast, muscadine grape genotypes (Vitis rotundifolia) are tolerant/resistant to PD. This is due to the unique biochemical composition of muscadine xylem. However, because of low protein concentration, conventional methods such as low-pressure chromatography and PAGE are unsuitable for grape xylem protein characterization. In addition, these procedures are tedious, time-consuming and require large amount of sample. This study reports a procedure for isolating and separating proteins from muscadine and bunch grape xylem tissue. The procedure consists of separation of xylem from cortex and phloem, removal of pigments and other gummy substances from xylem with ethanol: ethylacetate (2:1) and subsequent Capillary Electrophoretic (CE) analysis of xylem protein extracts to achieve desired resolution. Number of peaks, peak height and areas, retention time and baseline position were used to compare resolution and study the effect of sample and separation buffer. Xylem tissue proteins extracted with 0.05% sodium borate buffer (pH 8.3) and subjected to CE using 1.2% sodium borate (pH 8.3) as a separation buffer were found to yield most satisfactory resolution of grape xylem proteins. The data obtained by CE were consistent and reproducible, and hence, is well suited to obtain excellent resolution of xylem tissue protein for identifying differences in protein composition among the grape genotypes.

Key words: Capillary electrophoresis, grape, Vitis, xylem, Pierce’s disease, protein.