ABSTRACT
BACKGROUND: Fresh coconut (Cocos nucifera L) water is a clear, sterile, colourless, slightly acidic and naturally flavoured drink, mostly consumed in tropical areas. It is a rich source of nutrients and has been used for medical purposes. This study was designed to investigate changes in selected characteristics of coconut water after autoclaving, gamma irradiation and storage. Also, the study was designed for assessing the possibility of measuring the growth of bacterial in fresh, stored or sterilised coconut water using turbidity measurements (at wavelengths between 600 nm and 800 nm) or by dry biomass determinations. RESULTS: Portions of coconut water aseptically extracted from the matured fruit, (average pH of 6.33 ± 0.17) were either stored at 4°C, autoclaved at 121°C for 20 min., or irradiated with gamma rays at 5 kGy. Subsequent changes in selected characteristics were determined. Autoclaving, gamma irradiation and long term storage of coconut water at 4°C resulted both in the development of a pale to intense yellow colour and changes in turbidity. After storage, the dry matter content of fresh, autoclaved and irradiated coconut water by 52.0%, 23.5% and 5.0% respectively. There were also significant differences in the UV spectra before and after sterilisation and during the storage of the coconut water. Although changes in total carbohydrates were observed, they were not significant (p > 0.05). CONCLUSIONS: The enormous differences in the characteristics before and after storage suggests that the use of turbidity and dry biomass measurements for measuring the growth of bacteria in fresh, autoclaved and gamma irradiated coconut water before storage is practicable without any possibility of interference by the innate turbidity, colour and dry matter of the coconut water. However, this is not practicable after storing the coconut waters at 4°C, since there were increases in the turbidity and dry matter of the coconut water to levels that will mask the turbidity of a growing bacteria culture.
ABSTRACT
BACKGROUND: The emergence of drug resistant strains of Mycobacterium tuberculosis complex has made the management of tuberculosis difficult. Also, Mycobacterium species has a peculiar cell wall, made of an impermeable complex structure rich in mycolate, making the lyses of its cell difficult. In order to apply a radio-labelled-probe based detection of mutations in selected genes leading to drug resistance, we concede that the evaluation and modifications of nucleic acid extraction protocols that are less sophisticated and less prone to contamination would be useful in the management of tuberculosis in a resource-constrained setting. FINDINGS: The average amount of nucleic acids was determined for different extraction treatments. High temperature treatment only, yielded the lowest amount of nucleic acids, i.e. 15.7 +/- 3.2 mug. The average amount of nucleic acids obtained with the addition of TE and triton-X100, was 133.7 +/- 8.9 mug, while that obtained with the addition of TE only, and TE and SDS were 68.4 +/- 22.7 mug and 70.4 +/- 20.3 mug respectively. Other treatments yielded 28.8 +/- 6.7 mug, 32.5 +/- 2.4 mug and 36.9 +/- 15.5 mug. The average amount of nucleic acids obtained with high temperature treatment in TE, and that obtained by freezing prior to high temperature treatment, successfully amplified for the genes of interest (rpoB, KatG, rrs). CONCLUSION: We strongly recommend the use of 1x TE buffer, and freezing and heating for improved lysis of cultured M. tuberculosis, and therefore, as an effective method for the preparation of M. tuberculosis nucleic acid useful for PCR.
