Plant retroviruses: structure, evolution and future applications

Essam A. Zaki*

Genetic Engineering & Biotechnology Research Institute, GEBRI, Research Area, Borg El Arab, Post Code 21934, Alexandria, Egypt.

*Current Address; Department of Biological Sciences, 1392 Lilly Hall of Life Sciences, West Lafayette, IN 47907-1392, Phone: (765) 494-9837 Fax: (765) 496-1496, E-mail: [email protected] 

Accepted 20 May 2003

Abstract

Retroelements, which replicate by reverse transcription, have been detected in higher plants, higher animals, fungi, insects and bacteria. They have been classified into viral retroelements, eukaryotic chromosomal non-viral retroelements and bacterial chromosomal retroelements. Until recently, retroviruses were thought to be restricted to vertebrates.  Plant sequencing projects revealed that plant genomes contain retroviral-like sequences. This review aims to address the structure and evolution of plant retroviruses. In addition, it proposes future applications for these important key components of plant genomes.

Key words: Interspecies gene flow, plant genes vectors, plant retroviruses, retroelements, sequence divergence, transgenic plants.

 

 

Bacillus pumilus BpCRI 6, a promising candidate for cellulase production under conditions of catabolite repression

Kotchoni O.S.1*†, Shonukan O.O.¹ and Gachomo W.E.²

¹Department of Microbiology, Faculty of Science, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria.

²Institute for Plant Diseases, University of Bonn, Nussallee 9, D-53115 Germany.

*Corresponding author; Kotchoni O.S.,Tel: + 49-228-739581, Fax: + 49-228-732689, E-mail: [email protected] 

†Current Address: Department of Plant Molecular Biology, Institute of Botany, University of Bonn, Kirchallee 1, D-53115 Bonn, Germany.

Accepted 16 May 2003

Abstract

Cellulose degrading organisms have been used for the conversion of cellulolytic materials into soluble sugars or solvents in several biotechnological and industrial applications. In this report, a mutant of Bacillus pumilus was obtained after chemical mutagenesis and screened for cellulase production. This mutant named BpCRI 6 was selected for its ability to produce cellulase under catabolite repression. Cellulase yield by BpCRI 6 was four times higher than that of the wild type under optimum growth conditions (pH 6.5, 25°C and Ca2+ 1mM). In shaking flask cultures, production of cellulase  by the wild type was completely repressed in the presence of 25 mM glucose, while BpCRI 6 strain still exhibited a residual cellulase production of 80 and 40% at 25 mM and 40 mM of glucose concentrations respectively. The mutant strain is stable and grows rapidly in liquid and solid media. Under conditions of catabolite repression (40 mM of glucose), the production of cellulase by this mutant is particularly significant when compared to Trichoderma reesei a well-known cellulase producer, which is under control of end-product inhibition. This is the first report of a successful catabolite repression insensitivity of cellulase production by a mutant of B. pumilus.

Key words: Cellulase, Bacillus pumilus, BpCRI 6, Catabolite repression.

 

 

Production of poly-β-hydroxybutyrate (PHB) and differentiation of putative Bacillus mutant strains by  SDS-PAGE of total cell protein

Hikmet Katırcıoğlu¹*, Belma Aslım2, Zehra Nur Yüksekdað², Nazime Mercan³, Yavuz Beyatlı²

¹*Department of Biology Education, Gazi University, Ankara, Turkey

²Department of Biology, Faculty of Science, Gazi University, Ankara, Turkey

³Department of Biology, Faculty of Science, Pamukkale University, Denizli, Turkey

*Corresponding author; Fax: (90) 312 2228483, E-mail: [email protected],  [email protected] 

Accepted 16 May 2003

Abstract

In this study, the putative mutant strains of Bacillus megaterium Y6, B. subtilis K8, B. sphaericus X3 and B. firmus G2 were studied for their poly-b-hydroxybutyrate (PHB) production capacities. Mutations were induced by using UV light, acriflavin and 5-bromourasil. Total cell proteins were extracted from 59 strains and compared using SDS-PAGE. For each strain, percentage yield of PHB according to cell dry weight was determined in a range of 1.46-63.45%. PHB production of 8 mutant strains were found to increase in comparison with parental strains. However, no increase in PHB production of mutant strains of B. sphaericus X3 was found. It was also determined that the protein profiles of the mutant strains with high PHB yield generally differed from the protein profiles of parental strains.

Key words: Bacillus, poly-β-hydroxybutyrate, PHB, total cell protein.

 

 

Cellulase Production by Aspergillus flavus Linn Isolate NSPR 101 fermented in sawdust, bagasse and corncob

OJUMU, Tunde Victor¹*, SOLOMON, Bamidele Ogbe^2,e, BETIKU, Eriola^2,¡, LAYOKUN, Stephen Kolawole², and AMIGUN, Bamikole³

¹Engineering Materials Development Institute, P.M.B 611, Akure Nigeria.

²Department of Chemical Engineering, Obafemi Awolowo University, Ile-Ife, Nigeria.

³Department of Food Science and Technology, Federal Polytechnic Ado-Ekiti, Ekiti State, Nigeria.

*Correspondence Author; E-mail: [email protected] 

^¡Present Address: German Research Centre for Biotechnology (GBF), Biochemical Engineering Division, Mascheroder Weg 1, D-38124 Braunschweig, E-mail: [email protected], [email protected] 

^eE-mail: [email protected] 

Accepted 23 May 2003  

Abstract

Bagasse, corncob and sawdust were used as lignocellulosic substrates for the production of cellulase enzyme using Aspergillus flavus after ballmilling and pretreatment with caustic soda.  From the fermentation studies, sawdust gave the best result with an enzyme activity value of 0.0743IU/ml while bagasse and corncob gave 0.0573IU/ml and 0.0502IU/ml respectively. The three lignocellulosics gave their maximum enzyme activities at about the twelfth hour of cultivation, suggesting that the 12th hour is the optimum time when the enzyme may be harvested.

Key words:  Aspergillus flavus, cellulase activity, lignocellulosics.

 

Detection of DNA alteration in abnormal phenotype of broiler chicken male by random amplified polymorphic DNA (RAPD)

Bahy Ahmed Ali

Nucleic Acid Research Dept., Genetic Engineering & Biotechnology Research Institute (GEBRI), Mubarak City For Scientific Research & Technology Applications, Alexandria, Egypt. E-mail: [email protected]  or [email protected] 

Fax: 203 4593323

Accepted 12 May 2003

Abstract

RAPD technique was used in this study to detect DNA band variations between both normal and abnormal male of broiler chicken based on RAPD marker. DNA polymorphisms between normal and mutant birds were detected using fifteen oligonucleiotide primers. Using these primers, DNA band loss ranged from 25 to 75%. Data demonstrated that RAPD marker could detect DNA alterations.

Keywords: DNA alteration, RAPD, abnormal phenotype, male, broiler chicken.

 

 

Amplification of 1-amino-cyclopropane-1-carboxylic (ACC) deaminase from plant growth promoting rhizobacteria in Striga-infested soil

Olubukola O. Babalola^1,2*, Ellie O. Osir² , Abiodun I. Sanni1, George D. Odhiambo³, and  Wallace D. Bulimo^2,Ψ

¹Department of Botany and Microbiology, University of Ibadan, Ibadan, Nigeria

²International Centre of Insect Physiology and Ecology, Nairobi, Kenya

³Kenya Sugar Research Foundation, Kisumu, Kenya.

*Corresponding author: Tel: 234-803-703-5965; e-mail: [email protected] 

^ΨPresent address: Department of Biochemistry, University of Nairobi, Nairobi, Kenya.

Accepted 28 May 2003

Abstract 

Experiments were conducted in pots to determine the growth effect of different rhizobacteria on maize under Striga hermonthica infestation. Three bacteria were selected based on their plant growth promoting effects. Whole bacterial cells of the rhizobacteria were used to amplify 1-amino-cyclopropane-1-carboxylic acid (ACC) deaminase gene by polymerase chain reaction (PCR). Each bacterial inoculation increased agronomic characteristics of maize although not always to a statistically significant extent. The extent of growth enhancement differs between the isolates. Enterobacter sakazakii 8MR5 had the ability to stimulate plant growth, however in the PCR study, ACC deaminase was not amplified from this isolate, indicating that not all plant growth-promoting rhizobacteria contain the enzyme ACC deaminase. In contrast, an ACC deaminase specific product was amplified from Pseudomonas sp. 4MKS8 and Klebsiella oxytoca 10MKR7.  This is the first report of ACC deaminase in K. oxytoca.

Key words: 1-amino-cyclopropane-1-carboxylic acid, ACC deaminase, PCR, rhizobacteria, Striga hermonthica.

 

 

In-vitro inhibition of growth of some seedling blight inducing pathogens by compost-inhabiting microbes

S. Muhammad¹ and N. A. Amusa²*

¹Biological Sciences Department, Usman Dan fodiyo University Sokoto

²Institute of Agricultural Research and Training Obafemi Awolowo University, Moor Plantation, P.M.B 5029, Ibadan, Nigeria

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

Accepted 19 May 2003

Abstract

Compost-inhabiting bacteria were studied for their effect on seedling blight inducing pathogens. Aspergillus niger, Trichoderma harzianum, Bacillus cereus and Bacillus subtilis were the microbes found associated with cow dung, sawdust and rice husk composted soils. Sclerotium rolfsii, Fusarium oxysporum, Pythium aphanidermatum and Macrophomina phaseolina were isolated from blighted seedlings of Cowpea, while S. rolfsii, P. aphanidermatum, Helminthosporium maydis and Rhizoctonia solani were isolated from blighted maize seedlings. When these compost-inhabiting microbes were paired with the seedling blight inducing pathogens, T. harzianum grew on the mycelia of all the test fungal pathogens. B. cereus reduced the mycelia growth of Sclerotium rolfsii, F. oxysporum, P. aphanidermatum, H. maydis and R. solani, with inhibitory zones ranging from 35.5% to 53.3%. B. subtilis in culture also inhibited the mycelia growth of all tested pathogenic fungi with inhibitory zones of between 40.0% to 57.8%. The inhibitory activities of the compost-inhabiting microbes might partly be responsible for the efficacy of compost in reducing seedling blight diseases of crops.

Key words: seedling blight, growth inhibition, sawdust, cow dung, rice husk, compost soil.

 

 

Isolation, characterization, and phylogenetic analysis of copia-like retrotransposons in the Egyptian cotton Gossypium barbadense and its progenitors

Abdel Ghany A. Abdel Ghany¹ and Essam A. Zaki²*

¹Institute of Efficient Productivity, Zagazig University, Zagazig

²Genetic Engineering & Biotechnology Research Institute, GEBRI, Research Area, Borg El Arab, Post Code 21934, Alexandria, Egypt.

*Corresponding author; Current Address: Department of Biological Sciences, 1392 Lilly Hall of Life Sciences, West Lafayette, IN 47907-1392, Phone (765) 494-9837 Fax (765) 496-1496, E-mail: [email protected].   

Accepted 16 may 2003

Abstract

We have used the polymerase chain reaction to analyze copia-like retrotransposons in the Egyptian cotton and its progenitors. All three cotton species studied contain reverse transcriptase fragments from copia-like retrotransposons. Sequence analysis of these reverse transcriptase fragments reveals that each is different from the others, with predicted amino acid diversities between 9 and 94%. The detection of stop codons and insertions/deletions in the derived amino acid sequences of the Gossypium RT clones, suggests that these clones represent defective retrotransposons. The presence of these sequences in G. barbadense progenitors, however, suggests the presence of active retrotransposons capable of producing new functional copies at an appropriate rate to compensate for the mutational loss of old ones. Phylogenetic analysis provided strong bootstrap support for a monophyletic origin of plant copia-like retrotransposons, yet showed high diversity within all species. Our results suggest that both vertical transmission of copia-like retrotransposons within G. barbadense lineages, and horizontal transmission between G. barbadense and its progenitors have played major roles in the evolution of copia-like retrotransposons in Gossypium.

Keywords: Genome structure, Gossypium, repetitive DNA, polyploidy, sequence diversity, retrotransposons.

Abbreviations; PCR: polymerase chain reaction, RT: reverse transcriptase gene.