Mangosteen (Garcinia mangostana Linn.) is a highly beneficial fruit, containing potent bioactive compounds such as xanthones. However, the metabolite comparisons of mangosteen pericarp, aril and seed have not been described in detail previously. A comparative approach was undertaken in the present work to evaluate the effects of different ratios of solvent combination in the metabolite extraction of mangosteen. Gas chromatography-based metabolomics approach was performed to evaluate the efficiency of two metabolite extraction methods utilising different solvent extraction ratios (3/1/1 v/v or 2/1/2 v/v of methanol/chloroform/water) in determining the primary metabolite composition of mangosteen fruit tissues (pericarp, aril and seed). Cumulatively, 43 known metabolites were putatively identified from the mangosteen fruit tissues. Due to the higher ratio of polar solvent (methanol and water) used in method 2 as compared to method 1, the former method preferentially extracted a higher number of polar metabolites. Conversely, the higher ratio of methanol solvent in method 1 also contributed to the identification of more alcohol metabolites. Additionally, the multivariate analysis revealed that mangosteen pericarp was mainly localised by ribonic acid, arabinopyranose, β-hydroxypyruvic acid, L-(+)-tartaric acid and galacturonic acid. Meanwhile, thymol-α-D- glucopyranoside and D-ribofuranose contributed to the separation of mangosteen aril, whereas mangosteen seed contained high levels of β-D-galactofuranose, L-threonic acid, butanoic acid, glycoside, malic acid and myo-inositol. Results suggested that the differing solvent ratios can highly influence the types and levels of the extracted metabolites. This finding highlights the influence of metabolite solvent extraction methods towards the end results of the extraction as well as the localisation of primary metabolites in different mangosteen fruit tissues. Hence, the present work is vital in revealing important spatial information of various metabolites toward a better understanding of the mangosteen fruit ripening process.
Epinephelus fuscoguttatus is a commercially important marine fish species in southeast Asia. Due to overfishing and water pollution, this species has been declared as near-threatened. Thus, to provide information to help maintain and preserve the species, microsatellites were developed, using an enriched genomic library method. Thirty individuals were collected from the hatchery of the Fishery Research Institute, Terengganu, Malaysia. These individuals, from four to six years old, originated from Sabah and are maintained in captive culture as broodstock. Genomic DNA was extracted from the fins of selected individuals that weighed 3-8 kg. Ten microsatellite loci were found to be polymorphic in this population, with 5 to 21 alleles per locus. Observed and expected heterozygosities ranged from 0.53 to 0.97 and 0.59 to 0.95, respectively. Only one locus deviated significantly from Hardy-Weinberg equilibrium and no significant linkage disequilibrium was found among the pairs of loci. These polymorphic microsatellite loci will be used by the Malaysian Fishery Research Institute for investigating genetic diversity and for developing breeding strategies.
Temperature is one of the key factors in limiting the distribution of plants and controlling major metabolic processes. A series of simulated reciprocal transplant experiments were performed to investigate the effect of temperature on plant chemical composition. Polygonum minus of different lowland and highland origin were grown under a controlled environment with different temperature regimes to study the effects on secondary metabolites. We applied gas chromatography-mass spectrometry and liquid chromatography time-of-flight mass spectrometry to identify the chemical compounds. A total of 37 volatile organic compounds and 85 flavonoids were detected, with the largest response observed in the compositional changes of aldehydes and terpenes in highland plants under higher temperature treatment. Significantly less anthocyanidin compounds and larger amounts of flavonols were detected under higher temperature treatment. We also studied natural variation in the different plant populations growing under the same environment and identified compounds unique to each population through metabolite fingerprinting. This study shows that the origin of different plant populations influences the effects of temperature on chemical composition.