Journal of Applied Science in Southern Africa - latest Issue
Volume 8, Issue 2, 2002
Source: Journal of Applied Science in Southern Africa 8, pp 65 –75 (2002)More Less
The endoglucanase gene (celG) from B. subtilis CHZ1 was amplified by PCR, cloned and expressed in Escherichia coli DH5?. The amplified fragment with the structural gene was 2,589 bp and its nucleotide sequence was determined and analysed. The amplified fragment had an open reading frame of 1,524 bp encoding a predicted protein of 56,472 daltons in size with 508 amino acids. celG genes possible ribosomal binding site was identified and it resembled that of B. subtilis ?43 RNA polymerase. The gene contains a signal sequence codifying for a peptide of 38 amino acid residues. A BLASTN search showed 98 percent identities to endo-?-1,4-glucanase that has a predicted protein structure having a cellulases catalytic domain (CD) of 278 amino acids linked to a cellulose binding domain (CBD_3) with 83 residues. The enzyme was identified to belong to family-5A glycosyl hydrolases. There was no drastic reduction in endoglucanase activity during cultivation of the clones as was observed with the wild type strain.
Source: Journal of Applied Science in Southern Africa 8, pp 76 –88 (2002)More Less
Previous studies showed that the manually-operated peanut butter mills available on the market had technical problems related to the design and operation of the machines. One such problem was that the mills were too heavy for women to operate, resulting in limited operational time and ultimately, low total output. An ergonomic study of the original and modified versions of the mills was conducted at the University of Zimbabwe to verify the previously identified problems and develop appropriate and lighter mills for manual operation. A body discomfort assessment and heart rate measurement were used to determine stress endured by 12 women, as a result of operating the mills. Medium to high levels of discomfort were experienced in the lower back, neck, chest, lower arm, upper arm and shoulder.
Author C. SimangoSource: Journal of Applied Science in Southern Africa 8, pp 89 –98 (2002)More Less
The microbiological and acidic changes during the natural fermentation of mahewu, a nonalcoholic cereal beverage, and sour porridge were investigated. The presence of pathogenic yeasts in both products was also investigated. The study was carried out over a period of six months in the year 2000. The pH and total acidity as well as microbiological analysis were carried out at intervals of time during the fermentation period. There was a sharp decrease in pH in the mahewu and sour porridge broths in the first 12 to 24 hours of fermentation. Very little titratable acids were produced in the first 6 to 12 hours which was followed by a steady increase during the rest of the fermentation period. Enteric bacteria increased slightly in the first 12 hours but decreased sharply afterwards and could not be detected when the pH was around 3.5 whereas lactic acid bacteria predominated during the fermentation period. Yeasts increased in numbers as the pH dropped and were detected in lower numbers than lactic acid bacteria throughout the fermentation period.
Author J.D. BaggotSource: Journal of Applied Science in Southern Africa 8, pp 99 –110 (2002)More Less
Even though mammalian species differ in physical characteristics and behaviour, they possess the same body systems that perform generally similar physiological functions. There are, however, species-related physiological adaptations that account for the uniqueness of each species. Since most adaptations are of a quantitative nature, a trend or pattern may be discernible. Whenever the pattern can be descriptionbed by a mathematical equation, it becomes possible to make some predictions. The reliability of predictions involving interspecies extrapolation depends upon knowledge of the physiological similarities of and differences between the species of interest.
Author Mark J. ObwoloSource: Journal of Applied Science in Southern Africa 8, pp 111 –115 (2002)More Less
When we see cattle grazing on lush green pasture, horses galloping in the racecourse, guard dogs patrolling their masters homesteads, and cats rolling on the carpet, it all looks like peace and tranquillity for these animals; however, in such cases we are looking through just one window in the life of these animals. The fact is that, animals live in a potentially hostile environment, harbouring a variety of physical, chemical and biological agents of all sorts of characteristics some of which are poised to irritate, injure or even kill them. Some of the biological agents have the tendency and ability to colonize the animal body and propagate themselves within it. Some of them just get into a symbiotic relationship with the animal host, but others will inflict injuries to the animal.