Comparison of bacterial communities of tilapia fish from Cameroon and Vietnam using PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis)

Fishes in general and tilapia in particular are traded all over the world. However, it is difficult to find out their exact geographical location. One of the techniques used in the traceability of fish and its byproductsconsist in analysing in a global way the whole viable and non viable bacterial communities. For this purpose, the molecular technique employing the bacterial 16S DNA banding profiles generated by PCR-DGGE (polymerase chain reaction-Denaturing gradient gel electrophoresis) was used to evaluate the differences between the bacterial profiles of fishes from Vietnam (An Giang, south province) and those of Cameroon (Yagoua, Maga, Lagdo). The different PCR-DGGE 16S rDNA banding profiles obtained were analysed and results showed that there were specific bands for each geographical location though some bands common to Cameroon and Vietnam were observed. Thismethod could be used as a rapid analytical traceability tool for fish products and could be considered as a provider of a unique biological bar code

Antimicrobial activities, toxinogenic potential and sensitivity to antibiotics of Bacillus strains isolated from Mbuja, an Hibiscus sabdariffa fermented seeds from Cameroon

This study was carried out to screen for antimicrobial activities against common pathogenic and food spoilage bacteria, yeasts and molds, toxinogenic potential and sensitivity to antibiotics of 26 Bacillus strains (11 Bacillus subtilis, 5 Bacillus megaterium, 4 Bacillus amyloliquefaciens, 4 Bacillus pumilus and 2 Bacillus thuringiensis) isolated from different samples of Hibiscus sabdariffa fermented seeds (Mbuja). Antimicrobial assays were realised according to the cross-streak and the overlay methods. The main toxin and bacteriocin encoding genes were screened by PCR using specific primers and antibiotic resistance was assessed by the disc diffusion method. Bacillus species showed variable ability to inhibit bacterial and/or fungal species. The most antibacterial strains were B. amyloliquefaciens (S1 and S5) and B. subtilis (S12) whereas the most antifungal ones were B. megaterium S8 and S9. Subtilin and subtilosin A genes were detected in seven strains of B. subtilis but they were not associated with antimicrobial activities. All strains, except B. thuringiensis, did not contain toxin encoding genes and were sensitive to most tested antibiotics. This suggests that antimicrobial strains could be used in starter cultures for a controlled fermentation to produce Mbuja in order to better control the fermentation process of Mbuja and to increase consumer’s safety.Keywords: Bacillus, antimicrobial activities, toxins, antibiotic resistanceAfrican Journal of Biotechnology, Vol 13(31) 3617-362

Incidence of cassava root rot in the central region of Ghana

A survey of the incidence of Cassava root rot in the Central Region of Ghana was conducted from August to November, 1995. The main objective of the survey was to evaluate the economic importance of cassava root rot diseases in cassava production. All the twelve districts in the region were covered by the survey. From each district twenty cassava farmers were randomly selected out of forty farmers and they were interviewed using a questionnaire. The questionnaire was designed to find out the knowledge of farmers on the cassava root rot. The results indicated that 68.4% of cassava farmers in the region were aware of the occurrence of cassava root rot on their farms while 31.6 had not encountered it. The survey revealed that both soft and dry cassava root rot were well established in the Central Region except in one district, Dunkwa-On-Offin. The average incidence of soft cassava root rot in the various zones studied were: coastal districts (Komenda-Edina-Eguafo-Abrem, Mfantsiman, Awutu-Efutu-Senya and Gomoa) 36%; the penultimate coastal districts (Abura-Asiefu -Kwaman Kese, Ajumako-Enyan-Esiam and Agona Swedru) 30%; mid-region districts (Assin Foso and Asikuma-Odoben-Brakera), 21% and Forest District (Upper Denkyira and Lower Denkyira), 15%. For the dry root rot the incidences by zones at dry root rot were: Coastal District, 47%; the penultimate coastal districts, 18%. Mid-region districts, 13% and Forest Districts 27%. Six fungi were found to be associated with cassava root rot in the Central Region. They were Fusarium sp (white and dark colony types), Cunninghamella sp. Mortierella exigua Linnem, Glioclachum fimbricatum Gilman and Abbott, and Polyporus sulphureus Bull. Ex Fr. JOURNAL OF THE GHANA SCIENCE ASSOCIATION Volume 1 Number 1, July (1998) pp. 40-4

Effects of malting conditions on the properties of malt flour from some selected Cameroon maize varieties

The effect of malting conditions on some biochemical and functional properties of malt flours of grains of four selected maize cultivars was studied in a 3x4x5 factorial design. The studied factors were: the hydration levels of the gains prior to germination (30%, 45%, 60%), the maize cultivars used (CMS 8501, CMS 8704, CHC 201 and hybrid 88094xM131xExp24) and the germination times (0, 1, 2, 3, 4 days). The micro-malting method was used to assess maize germination and resulting malt flours obtained evaluated for functional characteritics. Grain germination rate was significantly affected (