Vol 7, No 1 .2006: African Scientist

Bacterial flora associated with some stages of Burukutu production

‘Burukutu’ which is an indigenous alcoholic drink has been shown to be rich in bacterial diversity, with a total of thirteen (11) bacterial species isolated from the three stages of production (namely: steeping, mashing and maturation) sampled from two different selling points in Ilorin, metropolis. The bacterial species isolated are Streptococcus sp; Lactobacillus sp; Bacillus sp; Pseudomonas sp; Klebsiella sp; Staphylococcus sp; Enterococcus sp; Escherichia coli; Proteus sp; Leuconostoc sp and Micrococcus sp.


Acute toxicity of mesocarp of Azadirachta indica (L.) (Neem plant) on fingerlings of Heterobranchus bidorsalis

The piscicidal potential of water-extract mesocarp of Azardirachta indica was investigated in static biossay experiment with continuous aeration to determine its acute toxicity. The 96-hLC50 was 97.42mg/l while the threshold value was 31.12mg/l. The extract led to an initial increase in opercula ventilation rates which then decreased significantly. The computed regression equation (y) = 4.624 + 6.352 Logc. (r=0.72) and the fish exhibited respiratory distress, loss of balance and erratic swimming prior to mortality. The usefulness of A. indica as piscicidal plant is discussed.

Assessment of integrity of three dispersants and their toxicity to a Brackishwater Cichlid, Sarotherodon melanotheron (Cichlidae)

Key physical characteristics of three dispersants: Corexit 9527, NalcoD4106 and Goldcrew were studied to determine their integrity and toxicity to a brackishwater fish Sarotherodon melanotheron. The results showed that with regards to the physical properties, Corexit 9527 and to a large extent Goldcrew maintained their integrity while NalcoD4106 deteriorated. Observations of the 96h LC50 static bioassay showed that the toxicity of the dispersants to the fish in an increasing order is Corexit 9527 < Goldcrew < NalcoD4106.

Fungicidal effect of pawpaw (Carica papaya L.) leaf extracts on Fusarium verticilliodes

The in vitro effect of 10, 30 and 50% (w/v) concentrations of the aqueous and ethanolic extracts of pawpaw (Carica papaya L.) leaf on the radial growth of Fusarium verticilliodes was studied using the pour plate method. The diameters of radial growth of the mycelia of F. verticilliodes were measured at 24 hours intervals for five days. Both extracts retarded the radial growth of F. verticilliodes compared to that of the control, with the ethanolic extract having a greater fungistatic effect at the concentrations tested in this study.


Salinity variations and distribution of Copepoda:Crustacea in the Lagos harbour system

: The copepoda (crustacea) of Lagos harbour system was studied from October 2002 to September 2003. Eighteen copepod species were identified, three of which are being recorded in Nigeria for the first time. Thesze are: Temora, Corycaeus and macrostella species. The copepods comprise of three assemblages, namely: the brackish/marine assemblage, the brackish assemblage and the brackish/freshwater assemblage. Salinity values varied from 33.40% at Lagos harbour to 0.40% at Badagry.


First record of the Ectoparasite Salmincola species (Crustacea) from Nigeria water body

Plankton sampling and investigation of the Lagos harbour, some adjourning creeks and rivers was carried out using plankton, nets of 55µm and 100µm mesh sizes. Yewa river which is located between Lat. 6°25’ – 6°30’N and Long. 2°50’ – 2°55’E was one of the sampling, stations with salinity values ranging from 0.17 – 0.43% for the 8 months of sampling period, indicating a constant freshwater condition. In the course of analysis and identification of the copepoda, Salmincola species which is an ectoparasite of fish was found, and this is its first record from Nigeria water body