Development of novel microsatellite markers using RAD sequencing technology for diversity assessment of rambutan (Nephelium lappaceum L.) germplasm.

The trend of microsatellite marker discovery and development revolved as a result of the advancement of next generation sequencing (NGS) technology as it has developed numerous microsatellites within a short period of time at a low cost. This study generated microsatellite markers using RAD sequencing technologies for the understudied Nephelium lappaceum. A total of 1403 microsatellite markers were successfully designed, which consisted of 853 di-, 525 tri-, 17 tetra-, 5 penta-, and 3 hexanucleotide microsatellite markers. Subsequently, selection of 39 microsatellites was made for the evaluation of genetic diversity of the selected 22 rambutan varieties. Twelve microsatellites, which exhibited high call rates across the samples, were used to assess the diversity of the aforementioned rambutan varieties. The analysis of 12 microsatellites revealed the presence of 72 alleles and six alleles per locus in average. Furthermore, the polymorphic information content (PIC) value ranged from 0.326 (NlaSSR20) to 0.832 (NlaSSR32), which included an average of 0.629 per locus, while the generated Neighbour Joining dendrogram showed two major clusters. The pairwise genetic distance of shared alleles exhibited a range of values from 0.046 (R134↔R170) to 0.818 (R5↔R170), which suggested highest dissimilarity detected between R5 and R170. Notably, these research findings would useful for varietal identification, proper management and conservation of the genetic resources, and exploitation and utilization in future breeding programs.

Comparing Palm Oil, Tocotrienol-Rich Fraction and α-Tocopherol Supplementation on the Antioxidant Levels of Older Adults.

BACKGROUND: Tocotrienol and tocopherol are known to prevent numerous degenerative diseases. The aim of this study is to compare the effects of tocotrienol-rich fraction (TRF) with α-tocopherol (α-TF) on the antioxidant status of healthy individuals aged between 50 and 55 years. METHODS: Volunteers were divided into groups receiving placebo (n = 23), α-TF (n = 24) and TRF (n = 24). Fasting venous blood samples were taken at baseline (0 month), 3 months and 6 months of supplementation for the determination of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities as well as for reduced glutathione (GSH) and oxidized glutathione (GSSG) concentrations. RESULTS: CAT and GPx were unaffected by TRF and α-TF supplementations. SOD activity increased significantly after six months of TRF supplementation. Analysis by gender showed that only female subjects had significant increases in SOD and GPx activities after six months of TRF supplementation. GPx activity was also significantly higher in females compared to males after six months of TRF supplementation. The GSH/GSSG ratio increased significantly after six months of TRF and α-TF supplementation in only the female subjects. CONCLUSION: TRF and α-TF supplementation exhibited similar effects to the antioxidant levels of older adults with TRF having more significant effects in females.

Comparing palm oil tocotrienol rich fraction with α-tocopherol supplementation on oxidative stress in healthy older adults.

Vitamin E is a fat-soluble compound and powerful antioxidant that have been shown to protect the cell membranes against damage caused by free radicals. Human vitamin E supplementation studies are usually limited to α-tocopherol but currently tocotrienols are also available. This study aims to compare the effects of tocotrienol rich fraction (TRF) with α-tocopherol (α-TF) supplementation on oxidative stress in healthy male and female older adults aged 50-55 years old. A total of 71 subjects both male and female aged between 50 and 55 years were divided into groups receiving placebo (n = 23), α-TF (n = 24) and TRF (n = 24) for six months. Blood was taken at baseline (month 0), 3 months and 6 months osf supplementation for determination of plasma malondialdehyde (MDA), protein carbonyl, total DNA damage, vitamin D concentration and vitamin E isomers. α-TF supplementation reduced plasma MDA and protein carbonyl in female subjects after 3 and 6 months. TRF supplementation reduced MDA levels in both males and females as early as 3 months while DNA damage was reduced in females only at 6 months. Supplementation with α-TF and TRF increased plasma vitamin D concentration in both males and females after 6 months, but vitamin D concentration in male subjects were significantly higher compared to female subjects in TRF group. Vitamin E isomer determination showed α-TF, α-tocotrienol and γ-tocotrienol were increased in both male and female subjects. In conclusion, TRF supplementation effects were different from α-TF in reducing oxidative stress markers and vitamin D levels with a more pronounced effect in female subjects.