Protective effect of aqueous extract from Spirulina platensis against cell death induced by free radicals

<p>Abstract</p> <p>Background</p> <p><it>Spirulina </it>is a commercial alga well known to contain various antioxidants, especially phycocyanin. Apart from being sold as a nutraceutical, <it>Spirulina </it>is incorporated as a functional ingredient in food products and beverages. Most of the previous reports on antioxidant activity of <it>Spirulina </it>were based on chemical rather than cell-based assays. The primary objective of this study was to assess the antioxidant activity of aqueous extract from <it>Spirulina </it>based on its protective effect against cell death induced by free radicals.</p> <p>Methods</p> <p>The antioxidant activity of the cold water extract from food-grade <it>Spirulina platensis </it>was assessed using both chemical and cell-based assays. In the cell-based assay, mouse fibroblast cells (3T3) cells were incubated for 1 h in medium containing aqueous extract of <it>Spirulina </it>or vitamin C (positive control) at 25, 125 and 250 μg/mL before the addition of 50 μM 1,1-diphenyl-2-picrylhydrazyl (DPPH) or 3-ethylbenzothiazoline-6-sulfonic acid (ABTS). The cells were incubated for another 24 h before being assessed for cell death due to apoptosis using the Cell Death Detection ELISA Kit. Spectrophotometric assays based on DPPH and ABTS were also used to assess the antioxidant activity of the extract compared to vitamin C and vitamin E (positive controls).</p> <p>Results</p> <p><it>Spirulina </it>extract did not cause cytotoxic effect on 3T3 cells within the range of concentrations tested (0 - 250 μg/mL). The extract reduced significantly (p < 0.05) apoptotic cell death due to DPPH and ABTS by 4 to 5-fold although the activity was less than vitamin C. Based on the DPPH assay, the radical scavenging activity of the extract was higher than phycocyanin and was at least 50% of vitamin C and vitamin E. Based on the ABTS assay, the antioxidant activity of the extract at 50 μmug/mL was as good as vitamin C and vitamin E.</p> <p>Conclusions</p> <p>The results showed that aqueous extract of <it>Spirulina </it>has a protective effect against apoptotic cell death due to free radicals. The potential application of incorporating <it>Spirulina </it>into food products and beverages to enhance their antioxidant capacity is worth exploring.</p

Molecular differentiation of two morphological variants of gracilaria salicornia

Xia in 1986 combined Gracilaria salicornia, G. canaliculata (G. crassa), G. cacalia and G. minor into one species: G. salicornia. Two morphological variants of G. salicornia were collected from different localities in Malaysia. Variant A collected from Morib, Selangor grew on the roots of Avicennia. The samples showed absence of main axis; segmented constrictions throughout; cylindrical or slightly compressed thalli. Variant B was collected from the mudflats of Tanjung Tuan, growing on rocks, coral or forming mats on the mud. Plants showed absence of main axis; segments were not constricted throughout the plant (if present only slightly articulated at the upper part), branching was dichotomous or irregular; cylindrical or slightly compressed thalli. The technique of Random Amplified Polymorphic DNA analysis (RAPD) was used to investigate molecular characteristics of the two variants. Out of sixty Operon primers that were screened, four primers, OPA 1, OPA 10, OPA 11 and OPK 7 were able to give polymorphism. The fingerprints generated were stable and reproducible on repeated analysis. The DNA fingerprints generated were visually analysed and clustering analysis was carried out using GelCompar 4.0. The matrix of similarities was based on the Dice coefficients (SD) and the cluster analysis was carried out using the unweighted pair group method using arithmetic averages (UPGMA). DNA analysis showed that two primers (OPA 01, CAGGCCCTTC and OPK 07, AGCGAGCAAG) were able to differentiate the two variants

Agar properties of Gracilaria species (Gracilariaceae, Rhodophyta) collected from different natural habitats in Malaysia

The yield and quality of agar from Gracilaria species collected from distinct natural habitats (mangrove swamp, rocky shore, sandy mudflat) along the west coast of Peninsular Malaysia were evaluated in this study. The agar content was found to be significantly higher in G. changii and G. edulis growing in the mangrove swamp, while the lowest agar content was recorded for G. changii and G. edulis collected from the sandy mudflat. Higher agar gel strength was obtained from the three Gracilaria species collected from the mangrove swamp compared to those that live in the sandy mudflat and rocky shore. The intraspecific variations found in gelling temperature were well correlated with the trend of changes in agar gel strength, except for G. changii collected from the sandy mudflat and rocky shore. The intraspecific and interspecific variations of agar melting temperature did not show a consistent trend for all Gracilaria species tested. The agars of Gracilaria spp. collected from the rocky shore showed a significantly higher gel syneresis while the lowest gel syneresis was recorded for the agars of samples collected from the mangrove swamp, except for the agars of G. salicornia from different habitats which showed no difference. In conclusion, the mangrove swamp is a natural habitat which produces Gracilaria with good agar properties, in terms of agar yield, gel strength and gel hysteresis, thus it can be considered as a potential site for seaweed farming and mariculture for the agar industry in Malaysia

Genetic and morphological analyses of Gracilaria firma and G. changii (Gracilariaceae, Rhodophyta), the commercially important agarophytes in western Pacific

Many studies classifying Gracilaria species for the exploitation of agarophytes and the development of the agar industry were conducted before the prevalence of molecular tools, resulting in the description of many species based solely on their morphology. Gracilaria firma and G. changii are among the commercially important agarophytes from the western Pacific; both feature branches with basal constrictions that taper toward acute apices. In this study, we contrasted the morpho-anatomical circumscriptions of the two traditionally described species with molecular data from samples that included representatives of G. changii collected from its type locality. Concerted molecular analyses using the rbcL and cox1 gene sequences, coupled with morphological observations of the collections from the western Pacific, revealed no inherent differences to support the treatment of the two entities as distinct taxa. We propose merging G. changii (a later synonym) into G. firma and recognize G. firma based on thallus branches with abrupt basal constrictions that gradually taper toward acute (or sometimes broken) apices, cystocarps consisting of small gonimoblast cells and inconspicuous multinucleate tubular nutritive cells issuing from gonimoblasts extending into the inner pericarp at the cystocarp floor, as well as deep spermatangial conceptacles of the verrucosatype. The validation of specimens under different names as a single genetic species is useful to allow communication and knowledge transfer among groups from different fields. This study also revealed considerably low number of haplotypes and nucleotide diversity with apparent phylogeographic patterns for G. firma in the region. Populations from the Philippines and Taiwan were divergent from each other as well as from the populations from Malaysia, Thailand, Singapore and Vietnam. Establishment of baseline data on the genetic diversity of this commercially important agarophyte is relevant in the context of cultivation, as limited genetic diversity may jeopardize the potential for its genetic improvement over time

Morphological and molecular evidence for the recognition of hypoglossum sabahense sp. Nov. (delesseriaceae, rhodophyta) from sabah, malaysia

Funding Information: This work was supported by the UK Natural Environment Research Council (NERC, Programme Oceans 2025, WP 4.5 and grant NE/D521522/1). This work also received support from the Marine Alliance for Science and Technology for Scotland pooling initiative. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions. FCK is grateful to faculty, staff and students at the Institute of Ocean and Earth Sciences of the University of Malaya for hosting his visits in November-December 2007 and November-December 2008. Dr. Akira F. Peters (Bezhin Rosko, 29250 Santec, Brittany, France) is acknowledged for his laboratory assistance. The University of Melbourne, School of Biosciences and the facilities provided by Prof. Geoffrey McFadden for 25 years have been invaluable for JAW’s culture programs and publications since 1994.Peer reviewedPublisher PD

Genetic diversity and population structure of terapon jarbua (Forskål, 1775) (teleostei, terapontidae) in malaysian waters

A background study is important for the conservation and stock management of a species. Terapon jarbua is a coastal Indo-Pacific species, sourced for human consumption. This study examined 134 samples from the central west and east coasts of Peninsular (West) Malaysia and East Malaysia. A 1446-bp concatenated dataset of mtDNA COI and Cyt b sequences was used in this study and 83 haplotypes were identified, of which 79 are unique haplotypes and four are shared haplotypes. Populations of T. jarbua in Malaysia are genetically heterogenous as shown by the high level of haplotype diversity ranging from 0.9167–0.9952, low nucleotide diversity ranging from 0.0288–0.3434, and high FST values (within population genetic variation). Population genetic structuring is not distinct as shown by the shared haplotypes between geographic populations and mixtures of haplotypes from different populations within the same genetic cluster. The gene flow patterns and population structuring observed among these regions are likely attributed to geographical distance, past historical events, allopatric speciation, dispersal ability and water currents. For instance, the mixture of haplotypes revealed an extraordinary migration ability of T. jarbua (>1200 km) via ancient river connectivity. The negative overall value of the neutrality test and a non-significant mismatch distribution are consistent with demographic expansion(s) in the past. The median-joining network concurred with the maximum likelihood haplotype tree with three major clades resolved. The scarcity of information on this species is an obstacle for future management and conservation purposes. Hence, this study aims to contribute information on the population structure, genetic diversity, and historical demography of T. jarbua in Malaysia

Distinct Genetic Lineages of Bactrocera caudata (Insecta: Tephritidae) Revealed by COI and 16S DNA Sequences

The fruit fly Bactrocera caudata is a pest species of economic importance in Asia. Its larvae feed on the flowers of Cucurbitaceae such as Cucurbita moschata. To-date it is distinguished from related species based on morphological characters. Specimens of B. caudata from Peninsular Malaysia and Indonesia (Bali and Lombok) were analysed using the partial DNA sequences of cytochrome c oxidase subunit I (COI) and 16S rRNA genes. Both gene sequences revealed that B. caudata from Peninsular Malaysia was distinctly different from B. caudata of Bali and Lombok, without common haplotype between them. Phylogenetic analysis revealed two distinct clades, indicating distinct genetic lineage. The uncorrected ‘p’ distance for COI sequences between B. caudata of Malaysia-Thailand-China and B. caudata of Bali-Lombok was 5.65%, for 16S sequences from 2.76 to 2.99%, and for combined COI and 16S sequences 4.45 to 4.46%. The ‘p’ values are distinctly different from intraspecific ‘p’ distance (0–0.23%). Both the B. caudata lineages are distinctly separated from related species in the subgenus Zeugodacus – B. ascita, B. scutellata, B. ishigakiensis, B. diaphora, B. tau, B. cucurbitae, and B. depressa. Molecular phylogenetic analysis indicates that the B. caudata lineages are closely related to B. ascita sp. B, and form a clade with B. scutellata, B. ishigakiensis, B. diaphora and B. ascita sp. A. This study provides additional baseline for the phylogenetic relationships of Bactrocera fruit flies of the subgenus Zeugodacus. Both the COI and 16S genes could be useful markers for the molecular differentiation and phylogenetic analysis of tephritid fruit flies