9 research outputs found
Antioxidative Responses of Tree Species in Ayer Hitam Forest, Selangor, Peninsular Malaysia
Antioxidative responses of eight tree species namely Atrocarpus elasticus, Endospermum diadenum, Vitex
pinnata, Pellacalyx axillaris, Garcinia atroviridis, Gironniera nervosa, Bouea Oppsitifolia and Callerya
atropurpurea were determined from samples collected from both the interior and fringe forest regions of Ayer
Hitam Forest Reserve. These antioxidative responses measured include the extent of oxidative deterioration of
cellular membrane lipids as well as the concentrations of ascorbate and a-tocopherol, two important endogeneous
antioxidants. All eight species showed significant differences in the extent of oxidative deterioration between
the interior and fringe forest regions where generally higher levels of membrane lipid peroxidation or oxidative
deterioration were observed in samples from the fringe forest regions except for V pinnata and G. nervosa.
Concentrations of a-tocopherol were also found to be generally higher in the fringe forest regions except for
V.pinnata and G. nervosa. Ascorbate concentrations were however found to be higher in all the tree species
sampled from the fringe forest. This thus indicates higher levels of stress conditions with respect to oxidative
stress manifested l7y higher levels of disturbance in the fringe forest regions. While G. atropurpurea may
represent a good and sensitive indicator species in determining stress conditions in the forest, V pinnata and
G. nervosa may represent tree species that are efficient in minimising oxidative deterioration in stress conditions
Paraquat (methyl viologen) toxicity in centella asiatica callus cultures
The effect ofparaquat (PQ) treatment on growth, cell viability, hydrogen peroxide (H202) and malondialdehyde (MDA) levels were investigated in the callus of two Centella asiatica accessions (CA03 and CA09). Callus of C. asiatica were treated with 50l1M PQforfive days in Murashige and Skoog (MS) liquid medium. Callus growth, viability ofthe callus as well as H202 content and MDA levels were evaluated at 0, 1, 2,3 and 5 days oftreatment periods. Fresh weight and dry weight of treated calli were significantly lower in CA03 as compared to the untreated calli. In CA09, the growth of treated calli was significantly lower compared to controls at the later stages ofthe treatment period. Although decreases in
growth were observedfor both treated CA03 and CA09, thefinal reduction in fresh weight at 36%for CA09 compared to its control was much higher compared to CA03 with an 18.2% final reduction in fresh weight. PQ treatment also
resulted in a marked decrease in the viability of the callus especially in CA09. Although MDA levels were significantly higher in treated CA03 as compared to treated CA09 at the early treatment stages, they showed a decreasing trend, while MDA levels in CA09 showed an increasing trend, which was significantly higher than that of CA03 at the end of the treatment period. In addition, H202 concentrations were generally higher in treated CA09 compared to treated CA03 except at day 3. This study indicated that PQ treatment can induce increases in levels of MDA and H202, associated with the decrease in growth and viability ofthe callus. Results also suggested that CA03 was more tolerant to PQ treatment as compared to CA09
The use of LP-RAPD for assessing genetic relatedness among selected banana cultivars
LP-RAPD (Long primer Random Amplified Polymorphic DNA) analysis was carried out on eight banana cultivars
namely Mas (AA), Berangan (AAA), Raja (AAB), Rastali (AAB), Awak (ABB), Nipah (BBB), Kapas (AAB) and Nangka (AAB) to assess their genetic relationships. Twenty five individuals of each cultivar were collected from the Malaysian states of Perak, Selangor, Melaka and Negeri Sembilan. Five long-primers, namely PEH A3, ERICIR, PUCMI3F, BOXAIR and PEHA6were selected to amplify the genomic DNA. The DNA bandingpatterns were observed and analyzed. The results showed that the largest fragment was 2500 bp and the smallest 100 bp. The ERICIR was found to be the most polymorphic primer (26.5 %) whilst PEHA6 was the least polymorphic (20.8 %). The dendrogram revealed three major groups. Group I consisted of Berangan, Rastali, Mas, Nangka and Raja cultivars. Group II included Kapas and Awak, which had the lowest genetic distance (0.3633) and are known as plantains by sharing the B genotype. Groups I and II were clustered closely together with a genetic distance of 0.3961 indicating a close relationship between the two groups. The Nipah (BBB) cultivar alone was distinctly separated from both Groups I and II with a genetic distance of 0. 795. Although all cultivars differ morphologically, the findings agree with the degree of shared genotypes, A or B, among the cultivars
Anthraquinones production, hydrogen peroxide level and antioxidant vitamins in Morinda elliptica cell suspension cultures from intermediary and production medium strategies
The effects of medium strategies [maintenance (M), intermediary (G), and production (P) medium] on cell growth, anthraquinone (AQ) production, hydrogen peroxide (H2O2) level, lipid peroxidation, and antioxidant vitamins in Morinda elliptica cell suspension cultures were investigated. These were compared with third-stage leaf and 1-month-old callus culture. With P medium strategy, cell growth at 49 g l–1, intracellular AQ content at 42 mg g–1 DW, and H2O2 level at 9 mol g–1 FW medium were the highest as compared to the others. However, the extent of lipid peroxidation at 40.4 nmol g–1 FW and total carotenoids at 13.3 mg g–1 FW for cultures in P medium were comparable to that in the leaf, which had registered sevenfold lower AQ and 2.2-fold lower H2O2 levels. Vitamin C content at 30–120 g g–1 FW in all culture systems was almost half the leaf content. On the other hand, vitamin E content was around 400–500 g g–1 FW in 7-day-old cultures from all medium strategies and reduced to 50–150 g g–1 FW on day 14 and 21; as compared to 60 g g–1 FW in callus and 200 g g–1 FW in the leaf. This study suggests that medium strategies and cell growth phase in cell culture could influence the competition between primary and secondary metabolism, oxidative stresses and antioxidative measures. When compared with the leaf metabolism, these activities are dynamic depending on the types and availability of antioxidants
Physical and biological parameters affecting transient GUS and GFP expression in banana via particle bombardment
Physical and biological parameters for DNA delivery into banana cultivar, Rastali (AAB) explants were optimised by monitoring transient gusA and gfp gene expression. Optimisation of the physical factors was carried out under the following conditions; helium pressure (450, 900, 1100, 1350 and 1550psi); distance from stopping plate to target tissue (3, 6, 9 and 12 cm); vacuum pressure (26, 27, 28 and 29 mmHg), number of bombardments (1, 2 and 3 times) per Petri dish and gold microcarrier size (0.6 and 1.0 µm). Distance from rupture disk to macrocarrier and macrocarrier to stopping screen was fixed at 4mm and 11mm, respectively. Two controls were also incorporated i.e. tissues without bombardment and bombardment of microcarrier without DNA. The biological parameters included the explant type (single bud and corm slice), influence of explant sizes (3, 5 and 10 mm), preculture treatment prior bombardment (0, 1, 2, 3 and 4 days), DNA concentrations (0.5, 1.0, 1.5, 2.0 and 2.5 µg) and effect of post-bombardment incubation time (3, 6, 9, 12, 15 and 18 days). Optimised bombardment conditions for single bud was bombarding twice at 1100 psi, 9cm target distance, 28 mmHg, 1 µM gold particle size, 3mm in size range, 1.5 µg DNA per bombardment, three days preculture prior to bombardment and six days post bombardment. For corm slice, the optimised bombardment conditions was bombarding once at a helium pressure of 1100 psi helium pressure, 9cm (gusA gene) or 6cm (gfp gene) target distance, 28 mmHg vacuum pressure and 1 mM gold particle size, 5mm in size range, 1.5 mg DNA per bombardment, one day preculture prior to bombardment and nine days post bombardment. Combinations of optimised physical and biological parameters and an effective selection system were developed which allowed high-efficiency of DNA delivery combined with minimum damage to target banana tissues
Statistical optimization of biohydrogen production using food waste under thermophilic conditions
In this study, optimization of biohydrogen production from food waste was investigated using response surface
methodology. The fermentation was conducted in a serum bottle with 100 mL working volume. A Preliminary experiment
showed that initial pH and temperature significantly influenced biohydrogen production. According to the central composite design, the optimal conditions for hydrogen yield were initial pH of 7.5 and temperature of 55.7oC, while the optimal conditions for hydrogen production rate were initial pH of 7.2 and temperature of 55.6oC. The maximum values for hydrogen yield and hydrogen production rate were 120 mL/g carbohydrate and 35.69 mL/h, respectively
Effect of different temperature, initial pH and substrate composition on biohydrogen production from food waste in batch fermentation
The aim of this study was to establish the optimum operating parameters for biohydrogen production from food waste. Batch fermentation was conducted using a 150 mL serum vial incubated in anaerobic condition. Heat-treated Palm Oil Mill Effluent (POME) sludge was used as the seed culture for biohydrogen production. Biohydrogen production was performed at different temperatures (35, 40, 50, 55 and 60°C), initial pH (5, 6, 7 and 8) and various compositions of sludge to substrate (10:90, 20:80, 30:70 and 40:60% (v/v)). The highest biohydrogen yield was 593 mL H2 g-1 carbohydrate for the experiment conducted at a temperature of 55°C, initial pH 7 and composition of sludge to substrate at 30:70% (v/v). The biohydrogen production from the waste was accompanied by the production of organic acids and the ratio of Hac/HBu was 0.87. Treatment efficiency as shown by Total Carbohydrate (TC), Total Suspended Solids (TSS) and Total Volatile Solids (TVS) reduction were 38, 25 and 18%, respectively
a-Tocopherol, ascorbic acid and carotenoid content in Centella asiatica leaf tissue and callus cultures.
Green leafy vegetables constitute a major part of balanced diet and are good sources of minerals and vitamins. These beneficial effects are attributed to the presence of antioxidants. Antioxidants also contribute to the defence mechanisms against oxidative stress. Centella asiatica, which is locally known as ‘pegaga,’ is claimed to be rich in natural antioxidative compounds. This study was conducted to determine the amount of ascorbic acid, α-tocopherol and carotenoid content in twelve accessions of C. asiatica (CA01 to CA12-comprises of ‘pegaga nyonya’, ‘pegaga kampung’ and ‘pegaga salad’) leaf tissues and callus cultures. The antioxidative constituents of C. asiatica in the leaf tissues and cultures were found to vary significantly between the accessions. In particular, CA03 leaves (‘pegaga salad’) exhibited the highest concentrations of ascorbic acid (95.86 ± 12.60 µg/g.fwt), whereas CA10 (‘pegaga nyonya’) produced the highest concentration of α-tocopherol (0.233 ± 0.029 µg/g.fwt) and carotenoids (36.55 ± 0.06 µg/g.fwt). The antioxidants studied were also successfully detected in the cultures of C. asiatica, with CA08 callus (‘pegaga kampung’) being dominant in ascorbic acid (167.21 ± 5.30 µg/g.fwt) and a-tocopherol (5.72 ± 0.29 µg/g.fwt), whereas CA12 callus (‘pegaga kampung’) had the highest carotenoid content (1.04 ± 0.07 µg/g.fwt). Meanwhile, the amount of non-enzymatic antioxidants (except for carotenoid content) was significantly higher in the cell cultures compared to the leaf tissues. The results indicated that CA03 and CA10 leaf tissues, as well as CA08 and CA12 calli were good sources of natural antioxidants compared to other accessions