Evaluation of Bacterial Diversity in Palm Wine by 16S rDNA Analysis of Community DNA

Bacterial diversity and fermentation dynamics in palm wine, a traditional alcoholic fermented beverage, collected from upright palm trees from Idiaba community, Abeokuta, Ogun State, Nigeria were evaluated by DNA based method using the 16S rDNA of the microbial community to verify and complement previous reports, improve our understanding and document yet unreported, uncultured microbial diversity associated with palm wine. The 16S rRNA gene fragments were amplified from microbial community and genomic DNA of isolates, by Polymerase Chain Reaction (PCR) using universal primers; and sequenced. The partial sequences were identified by comparison with sequences deposited in the non-redundant nucleotide database of National Center for Biotechnology Information(NCBI). This analysis revealed that 32 community clones were identified as Lactobacillus sp, Lactobacillus casei strain zhang, Lactobacillus plantarum, Leuconostoc mesenteriodes ssp dextranicum, Leuconcostoc lactis, Pediococcus parvulus strain Bpe-299, Acetobacter pomorum, Acetobacter pasteurianus, Gluconobacter oxydans, Acinetobacter calcoaceticus, Enterobacterium bacterium, Acidovorax sp, Comamonas sp, Bacillus subtilis, Staphylococcus piscifermentans and uncultured bacteria clone D1-78. The results showed that bacterial diversity in the palm wine sample is dominated by Lactobacillus and Leuconostoc species as reportedby previous workers and uncultured bacteria clone D1-78 (1 clone) was detected for the first time in palm wine.Keywords: Palm wine, 16S rRNA gene, community DNA, PCR, lactic acid bacteria

Rapid Screening of In-Vitro Regenerated Plantlets of Four Nigerian Cowpea Varieties to Artificially-Inoculated Fungal Wilt Pathogen

Tissue culture technique provides a rapid means of studying plant-pathogen interaction in a controlled environment with further advantage of saving time and resources. Embryonic axes of three local cowpea (Vigna unguiculata (L.) Walp) varieties (Oloyin, Ife-Brown and Erusu) and one elite line IT86D-1010 were cultured in-vitro and plantlets challenged with spore inoculum of Fusarium wilt pathogen – Fusarium oxysporum f.sp. tracheiphilum in order to determine the response of the plantlets to the pathogen infestation. A solid MS medium amended with growth hormone, benzylaminopurine BAP at 1, 2, and 3 mg BAP/L was used for shoot induction. Mean disease severity score of 4.9 was recorded for Oloyin variety. There was no significant difference between the response of Ife-Brown cowpea variety and IT86D-1010 to Fusarium wilt pathogen. Least disease severity score of 2.9 was recorded for Erusu variety. Erusu was also consistently low in disease incidence and severity all through the assessment period. It was suggested that local Erusu variety be screened on the field for confirmation of this in-vitro observation.Keywords: cowpea, in-vitro regeneration, hormones, Fusarium wilt, protocolsNig J. Biotech. Vol. 25 (2013) 12-1

Microbial Evaluation of Lafun in Selected Eateries in Abeokuta Metropolis, Nigeria

Lafun paste, a product of fermented cassava has been reported to be contaminated with food borne and opportunistic pathogens due to unhygienic practices during preparation. This study assessed the microbial safety of lafun paste (LP) sold in three selected eateries from five locations in Abeokuta, Nigeria. Total viable bacteria count (TVC), total coliform count (TCC), fungal count (FC) and lactic acid bacteria count (LAB count) were determined using standard laboratory procedures. The isolates were further identified using 16S rRNA gene sequencing and universal primers 27F and 1525R. A 24 aerobic bacteria and 10 anaerobes were isolated from LP. TVC for LP ranged from 6.90 to 7.86 Log CFU/g while the TCC ranged from 4.30-5.00 Log CFU/g. The identified bacterial isolated include Alcaligenes faecalis, Klebsiella pneumonia, Pseudomonas aeruginosa, Salmonella typhimurium, Pseudomonas stutzeri, Bacillus subtilis, Lactobacillus plantarum, Weissella confusa.Keywords: Microorganisms, lafun, food safety, microorganisms identification