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Mbita Z.,University of South Africa | Meyer M.,University of the Western Cape | Skepu A.,Mintek | Hosie M.,University of Witwatersrand | And 2 more authors.
Molecular and Cellular Biochemistry | Year: 2012

Retinoblastoma binding protein 6 (RBBP6) is a nuclear protein, previously implicated in the regulation of cell cycle and apoptosis. The human RBBP6 gene codes for three protein isoforms and isoform 3 consists of the domain with no name domain only whilst the other two isoforms, 1 and 2 comprise of additional zinc, RING, retinoblastoma and p53 binding domains. In this study, the localization of RBBP6 using RBBP6 variant 3 mRNA-specific probe was performed to investigate the expression levels of the gene in different tumours and find a link between RBBP6 and human carcinogenesis. Using FISH, real-time PCR and Western blotting analysis our results show that RBBP6 isoform 3 is down-regulated in human cancers. RBBP6 isoform 3 knock-down resulted in reduced G2/M cell cycle arrest whilst its over-expression resulted in increased G2/M cell cycle arrest using propidium iodide DNA staining. The results further demonstrate that the RBBP6 isoform 3 may be the cell cycle regulator and involved in mitotic apoptosis not the isoform 1 as previously reported for mice. In conclusion, these findings suggest that RBBP6 isoform 3 is a cell cycle regulator and may be de-regulated in carcinogenesis. © 2011 Springer Science+Business Media, LLC.

Schonfeldt H.C.,University of Pretoria | van Heerden S.M.,Agricultural Research Council of South Africa | Sainsbury J.,University of Pretoria | Gibson N.,University of Pretoria
South African Journal of Animal Sciences | Year: 2011

The study compared the nutrient content of selected joints of South African mutton (Class C2) (n = 18) and lamb (Class A2) (n = 18) carcasses of fat code 2 in both classes. South African sheep carcasses are classified according to age by dentition: Lamb carcasses of class A2 show the ruction of no incisors and mutton carcasses of class C2 of more than six incisors. Fatness is assessed by the thickness of subcutaneous fat. Chilled carcass sides were subdivided into the primal cuts. The cuts were dissected into meat (muscle, intermuscular and intramuscular fat), bone and subcutaneous fat (SCF). The soft tissue of the carcass was analysed for selected nutrients. It was found that South African lamb and mutton contain less fat than the nutrient values previously assumed as scientifically correct and presented in the National Food Composition Tables of the Medical Research Council (MRC), USDA. The results from this study emphasize the importance of country specific nutrient data on own food commodities.

North M.K.,Stellenbosch University | Frylinck L.,Agricultural Research Council of South Africa | Hoffman L.C.,Stellenbosch University
Meat Science | Year: 2015

This study aimed to determine the optimum ageing period for vacuum-packed springbok (Antidorcas marsupialis) Longissimus thoracis et lumborum (LTL) and Biceps femoris (BF) muscle stored at 5.4. ±. 1.0. °C. Portions of muscle from seven male and six female springbok were aged 1, 2, 5, 8, 14 or 21. days. The Warner Bratzler shear force declined most during the first five days post-mortem (PM), while purge and cooking losses increased significantly with ageing. Calpains I and II and calpastatin activity declined significantly up to five days PM, suggesting that they may be responsible for tenderization. Cathepsins B, BL and H activity increased significantly during ageing. The BF muscle had significantly higher pH, lower purge loss, higher cooking loss, higher WBSF and higher calpain and calpastatin activity than the LTL. No significant differences between the genders or muscles were found for the collagen content or collagen solubility. Springbok LTL and BF muscles should not be aged for longer than five days. © 2015 Elsevier Ltd.

Schonfeldt H.C.,University of Pretoria | Hall N.G.,University of Pretoria | Smit L.E.,Agricultural Research Council of South Africa
Food Research International | Year: 2012

Milk is a food with high nutritional benefits and is therefore considered an important source of food for all age groups. Laben (1963) reported that whole milk provides energy from carbohydrates, essential amino acids, fatty acids, vitamins and minerals in varying amounts, brought about by both environmental and genetic differences. Not only has the economic impact of variation in fat and protein content led to much research on manipulation and alteration of these constituents, but the different amino acid, fatty acid and micronutrient profiles, and their consequent impact on health, have become current topics of debate. Increased knowledge of the impact of feeding on the quality and quantity of milk production has led to more sophisticated diet formulations for cattle (Jenkins & McGuire, 2006). In the 1980s, diets were modified to induce changes in fat percentage, protein and lactose content. Apart from diet, breed and other environmental factors influence the composition of milk. Nutritional composition forms the basis of consumer education, and it is evident that international data for milk cannot be used in all contexts. During this study country specific composition data for milk is compared and the differences discussed. © 2011 Elsevier Ltd.

North M.K.,Stellenbosch University | Frylinck L.,Agricultural Research Council of South Africa | Hoffman L.C.,Stellenbosch University
Meat Science | Year: 2016

This study describes the changes taking place during rigour in springbok (Antidorcas marsupialis) Longissimus thoracis et lumborum (LTL) and Biceps femoris (BF) muscles. Samples from six male and six female springbok were snap-frozen at 2, 3, 5, 8, 12, 18, 24 and 30. h post- mortem (PM) and the pH, calpains I, II and calpastatin activities and cathepsins B, BL and H activities were determined. The temperature was also recorded. Significant third-order interactions were found for the pH and temperature, with the female LTL cooling more rapidly and acidifying slower than the other samples. Female muscles were at risk of developing cold-shortening and all the samples cooled more rapidly than recommended for cattle or sheep. Cathepsin BL activity increased PM, likely due to the degradation of the lysosomes. Calpains I, II and calpastatin activity declined during rigour, indicating that the calpains were activated early PM. Gender and muscle had a significant effect on calpain and cathepsin activity. © 2015 Elsevier Ltd.

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