Displaying publications 1 - 20 of 22 in total

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  1. Fulltext Genetic and morphological analyses of Gracilaria firma and G. changii (Gracilariaceae, Rhodophyta), the commercially important agarophytes in western Pacific
    Ng PK, Lin SM, Lim PE, Hurtado AQ, Phang SM, Yow YY, et al.
    PLoS One, 2017;12(7):e0182176.
    PMID: 28759629 DOI: 10.1371/journal.pone.0182176
    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 verrucosa-type. 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.
    Matched MeSH terms: Gracilaria/classification; Gracilaria/cytology; Gracilaria/genetics*
  2. Fulltext Optimization of nucleic acid extraction and amplification of a thiamine biosynthesis gene fragment from selected Malaysian seaweeds
    Md Ahaik FA, Mohd Taufik SH, Faiqah Johari NA, Zainal Abidin AA, Balia Yusof ZN
    Genes Genet Syst, 2023 Feb 22;97(5):247-256.
    PMID: 36631109 DOI: 10.1266/ggs.22-00088
    Obtaining high-quality nucleic acid extracted from seaweeds is notoriously difficult due to contamination with polysaccharides and polyphenolic compounds after cell disruption. Specific methods need to be employed for RNA isolation in different seaweed species, and therefore studies of the thiamine biosynthesis pathway have been limited. Two selected Malaysian species which are highly abundant and underutilized, namely Gracilaria sp. and Padina sp., representing the red and brown seaweeds, respectively, were collected to develop optimized total RNA extraction methods. Prior to that, DNA was extracted, and amplification of the 18S rRNA gene and the THIC gene (encoding the first enzyme in the pyrimidine branch of the thiamine biosynthesis pathway) from the DNA template was successful in Gracilaria sp. only. RNA was then extracted from both seaweeds using three different existing methods, with some modifications, using cetyltrimethylammonium bromide, guanidine thiocyanate and sodium dodecyl sulphate. Methods I and III proved to be efficient for Padina sp. and Gracilaria sp., respectively, for the extraction of highly purified RNA, with A260/A280 values of 2.0 and 1.8. However, amplification of the housekeeping gene glyceraldehyde-3-phosphate dehydrogenase and the THIC gene was successful in only Gracilaria sp. cDNA derived from extracted RNA. Further modifications are required to improve the exploitation of nucleic acids from brown seaweeds, which has been proven to be difficult. This work should pave the way for molecular studies of seaweeds generally and for the elucidation, specifically, of the thiamine biosynthesis pathway.
    Matched MeSH terms: Gracilaria*
  3. Fulltext Complete chloroplast genome of Gracilaria firma (Gracilariaceae, Rhodophyta), with discussion on the use of chloroplast phylogenomics in the subclass Rhodymeniophycidae
    Ng PK, Lin SM, Lim PE, Liu LC, Chen CM, Pai TW
    BMC Genomics, 2017 Jan 06;18(1):40.
    PMID: 28061748 DOI: 10.1186/s12864-016-3453-0
    BACKGROUND: The chloroplast genome of Gracilaria firma was sequenced in view of its role as an economically important marine crop with wide industrial applications. To date, there are only 15 chloroplast genomes published for the Florideophyceae. Apart from presenting the complete chloroplast genome of G. firma, this study also assessed the utility of genome-scale data to address the phylogenetic relationships within the subclass Rhodymeniophycidae. The synteny and genome structure of the chloroplast genomes across the taxa of Eurhodophytina was also examined.

    RESULTS: The chloroplast genome of Gracilaria firma maps as a circular molecule of 187,001 bp and contains 252 genes, which are distributed on both strands and consist of 35 RNA genes (3 rRNAs, 30 tRNAs, tmRNA and a ribonuclease P RNA component) and 217 protein-coding genes, including the unidentified open reading frames. The chloroplast genome of G. firma is by far the largest reported for Gracilariaceae, featuring a unique intergenic region of about 7000 bp with discontinuous vestiges of red algal plasmid DNA sequences interspersed between the nblA and cpeB genes. This chloroplast genome shows similar gene content and order to other Florideophycean taxa. Phylogenomic analyses based on the concatenated amino acid sequences of 146 protein-coding genes confirmed the monophyly of the classes Bangiophyceae and Florideophyceae with full nodal support. Relationships within the subclass Rhodymeniophycidae in Florideophyceae received moderate to strong nodal support, and the monotypic family of Gracilariales were resolved with maximum support.

    CONCLUSIONS: Chloroplast genomes hold substantial information that can be tapped for resolving the phylogenetic relationships of difficult regions in the Rhodymeniophycidae, which are perceived to have experienced rapid radiation and thus received low nodal support, as exemplified in this study. The present study shows that chloroplast genome of G. firma could serve as a key link to the full resolution of Gracilaria sensu lato complex and recognition of Hydropuntia as a genus distinct from Gracilaria sensu stricto.

    Matched MeSH terms: Gracilaria/classification; Gracilaria/cytology*; Gracilaria/genetics*
  4. Unraveling the nuclear and chloroplast genomes of an agar producing red macroalga, Gracilaria changii (Rhodophyta, Gracilariales)
    Ho CL, Lee WK, Lim EL
    Genomics, 2018 03;110(2):124-133.
    PMID: 28890206 DOI: 10.1016/j.ygeno.2017.09.003
    Agar and agarose have wide applications in food and pharmaceutical industries. Knowledge on the genome of red seaweeds that produce them is still lacking. To fill the gap in genome analyses of these red algae, we have sequenced the nuclear and organellar genomes of an agarophyte, Gracilaria changii. The partial nuclear genome sequence of G. changii has a total length of 35.8Mb with 10,912 predicted protein coding sequences. Only 39.4% predicted proteins were found to have significant matches to protein sequences in SwissProt. The chloroplast genome of G. changii is 183,855bp with a total of 201 open reading frames (ORFs), 29 tRNAs and 3 rRNAs predicted. Five genes: ssrA, leuC and leuD CP76_p173 (orf139) and pbsA were absent in the chloroplast genome of G. changii. The genome information is valuable in accelerating functional studies of individual genes and resolving evolutionary relationship of red seaweeds.
    Matched MeSH terms: Gracilaria/classification; Gracilaria/genetics*
  5. Fulltext Development of chloroplast simple sequence repeats (cpSSRs) for the intraspecific study of Gracilaria tenuistipitata (Gracilariales, Rhodophyta) from different populations
    Song SL, Lim PE, Phang SM, Lee WW, Hong DD, Prathep A
    BMC Res Notes, 2014;7:77.
    PMID: 24490797 DOI: 10.1186/1756-0500-7-77
    Gracilaria tenuistipitata is an agarophyte with substantial economic potential because of its high growth rate and tolerance to a wide range of environment factors. This red seaweed is intensively cultured in China for the production of agar and fodder for abalone. Microsatellite markers were developed from the chloroplast genome of G. tenuistipitata var. liui to differentiate G. tenuistipitata obtained from six different localities: four from Peninsular Malaysia, one from Thailand and one from Vietnam. Eighty G. tenuistipitata specimens were analyzed using eight simple sequence repeat (SSR) primer-pairs that we developed for polymerase chain reaction (PCR) amplification.
    Matched MeSH terms: Gracilaria/classification; Gracilaria/genetics*; Gracilaria/isolation & purification
  6. Kesan penggunaan rumpai laut sebagai agen penapis semula jadi dalam pengkulturan intensif rotifer brachionus plicatilis
    Razak A, Zaidi C, Zainoddin J, Majid A, Toda T, Othman B
    Sains Malaysiana, 2015;44:891-898.
    Penyelidikan ini dijalankan untuk menilai kesan penggunaan tiga spesies rumpai laut iaitu Ulva sp., Gracilaria sp. dan
    Kappaphycus sp. sebagai agen penapis semula jadi untuk menstabilkan pengkulturan rotifer dengan menggunakan
    petunjuk kaedah kuantitatif iaitu membandingkan nilai pertumbuhan seketika per hari rotifer Brachionus plicatilis. Kadar
    pertumbuhan seketika per hari rotifer dengan penggunaan Ulva sp. (p<0.01), Gracilaria sp. (p<0.05) dan Kappaphycus
    sp. (p<0.05) pada berat basah 7 g dalam 10 L air laut menunjukkan kesan yang ketara berbanding kawalan. Bagi
    kesemua rumpai laut yang diuji, keputusan menunjukkan setelah tercapainya nilai min kadar pertumbuhan seketika per
    hari rotifer yang tertinggi, penambahan jumlah berat penggunaan rumpai laut memberikan kesan penurunan kepada
    kadar pertumbuhan seketika rotifer. Keputusan menunjukkan Ulva sp. sesuai digunakan sebagai penapis biologi.
    Matched MeSH terms: Gracilaria
  7. Analisis kinetik pengeringan rumpai laut gracilaria changii menggunakan sistem pengering suria
    Mohd Yusof Othman, Ahmad Fudholi, Kamaruzzaman Sopian, Mohd Hafiz Ruslan, Muhammad Yahya
    Sains Malaysiana, 2012;41:245-252.
    Sistem pengering suria untuk pengeringan hasil pertanian dan laut telah direka bentuk, dibina dan diuji dalam suasana cuaca di Malaysia. Sistem pengeringan suria yang dibina, diuji untuk mengeringkan rumpai laut Gracilaria changii. Rumpai laut yang dikeringkan mempunyai kandungan air sekitar 95% asas berat basah untuk menghasilkan produk kering yang mempunyai kandungan air 10%. Proses pengeringannya mengambil masa selama kira-kira 7 jam, pada purata keamatan sinaran suria 593 W/m2 dan kadar aliran udara pengering 0.0613 kg/s. Pemadanan tiga model pengeringan telah dilakukan dengan data uji kaji pengeringan rumpai laut menggunakan sistem pengering suria pada suhu udara purata dalam kebuk 50oC dan purata kelembapan relatif udara 20%. Kejituan padanan model ditentukan berdasarkan nilai R2 yang paling tinggi, juga nilai MBE dan RMSE yang paling rendah. Kajian ini mendapati model pengeringan rumpai laut yang sesuai adalah model pengeringan Page dibandingkan dengan model pengeringan yang lain (model pengeringan Newton dan model Henderson dan Pabis).
    Matched MeSH terms: Gracilaria
  8. Fulltext Radiation of the red algal parasite Congracilaria babae onto a secondary host species, Hydropuntia sp. (Gracilariaceae, Rhodophyta)
    Ng PK, Lim PE, Phang SM
    PLoS One, 2014;9(5):e97450.
    PMID: 24820330 DOI: 10.1371/journal.pone.0097450
    Congracilaria babae was first reported as a red alga parasitic on the thallus of Gracilaria salicornia based on Japanese materials. It was circumscribed to have deep spermatangial cavities, coloration similar to its host and the absence of rhizoids. We observed a parasitic red alga with morphological and anatomical features suggestive of C. babae on a Hydropuntia species collected from Sabah, East Malaysia. We addressed the taxonomic affinities of the parasite growing on Hydropuntia sp. based on the DNA sequence of molecular markers from the nuclear, mitochondrial and plastid genomes (nuclear ITS region, mitochondrial cox1 gene and plastid rbcL gene). Phylogenetic analyses based on all genetic markers also implied the monophyly of the parasite from Hydropuntia sp. and C. babae, suggesting their conspecificity. The parasite from Hydropuntia sp. has a DNA signature characteristic to C. babae in having plastid rbcL gene sequence identical to G. salicornia. C. babae is likely to have evolved directly from G. salicornia and subsequently radiated onto a secondary host Hydropuntia sp. We also recommend the transfer of C. babae to the genus Gracilaria and propose a new combination, G. babae, based on the anatomical observations and molecular data.
    Matched MeSH terms: Gracilaria/parasitology*
  9. Effects of season on the yield and quality of extracts from Gracilaria changii (Gracilariaceae, Rhodophyta)
    Sasidharan S, Darah I, Jain K
    Sains Malaysiana, 2009;38.
    The effect of season on yield and quality of organic solvent extracts from Gracilaria changii was determined. The sustainability of the bioactive compound of G. changii from Malaysia was investigated by using the TLC and FTIR standards methods. Studies was carried out to examine the sustainability of the bioactive compound in the various extract obtained from G. changii collected from Pantai Morib, Beach Selangor Malaysia on bimonthly for a period of one year in 2003. This study revealed that the bioactive compounds was present all over the year but with different quantities. In general the variation in yield or quantities of bioactive compound was related to environment. G. changii can be considered a candidate for drug development since it retained the number of bioactive compound.
    Matched MeSH terms: Gracilaria
  10. Profiling the transcriptome of Gracilaria changii (Rhodophyta) in response to light deprivation
    Ho CL, Teoh S, Teo SS, Rahim RA, Phang SM
    Mar Biotechnol (NY), 2009 Jul-Aug;11(4):513-9.
    PMID: 19043658 DOI: 10.1007/s10126-008-9166-x
    Light regulates photosynthesis, growth and reproduction, yield and properties of phycocolloids, and starch contents in seaweeds. Despite its importance as an environmental cue that regulates many developmental, physiological, and biochemical processes, the network of genes involved during light deprivation are obscure. In this study, we profiled the transcriptome of Gracilaria changii at two different irradiance levels using a cDNA microarray containing more than 3,000 cDNA probes. Microarray analysis revealed that 93 and 105 genes were up- and down-regulated more than 3-fold under light deprivation, respectively. However, only 50% of the transcripts have significant matches to the nonredundant peptide sequences in the database. The transcripts that accumulated under light deprivation include vanadium chloroperoxidase, thioredoxin, ferredoxin component, and reduced nicotinamide adenine dinucleotide dehydrogenase. Among the genes that were down-regulated under light deprivation were genes encoding light harvesting protein, light harvesting complex I, phycobilisome 7.8 kDa linker polypeptide, low molecular weight early light-inducible protein, and vanadium bromoperoxidase. Our findings also provided important clues to the functions of many unknown sequences that could not be annotated using sequence comparison.
    Matched MeSH terms: Gracilaria/genetics*; Gracilaria/metabolism
  11. TRANSCRIPTOMIC ANALYSIS OF GRACILARIA CHANGII (RHODOPHYTA) IN RESPONSE TO HYPER- AND HYPOOSMOTIC STRESSES(1)
    Teo SS, Ho CL, Teoh S, Rahim RA, Phang SM
    J Phycol, 2009 Oct;45(5):1093-9.
    PMID: 27032354 DOI: 10.1111/j.1529-8817.2009.00724.x
    Osmotic stress is one of the most significant natural abiotic stresses that occur in the intertidal zones. Seaweeds may physiologically acclimate to changing osmolarity by altering their transcriptome. Here, we investigated the transcriptomic changes of Gracilaria changii (B. M. Xia et I. A. Abbott) I. A. Abbott, J. Zhang et B. M. Xia in response to hyper- and hypoosmotic stresses using a cDNA microarray approach. Microarray analysis revealed that 199 and 200 genes from ∼3,300 genes examined were up- and down-regulated by >2-fold in seaweed samples treated at 50 parts per thousand (ppt) artificial seawater (ASW) compared with those at 30 ppt ASW, respectively. The number of genes that were up- and down-regulated by >2-fold in seaweed samples treated at 10 ppt ASW compared with those at 30 ppt ASW were 154 and 187, respectively. A majority of these genes were only differentially expressed under hyper- or hypoosmotic conditions, whereas 67 transcripts were affected by both stresses. The findings of this study have shed light on the expression profiles of many transcripts during the acclimation of G. changii to hyperosmotic and hypoosmotic conditions. This information may assist in the prioritization of genes to be examined in future studies.
    Matched MeSH terms: Gracilaria
  12. Fulltext Morphological Characteristics and Habitats of Red Seaweed Gracilaria spp. (Gracilariaceae, Rhodophyta) in Santubong and Asajaya, Sarawak, Malaysia
    Othman MNA, Hassan R, Harith MN, Sah ASRM
    Trop Life Sci Res, 2018 Mar;29(1):87-101.
    PMID: 29644017 MyJurnal DOI: 10.21315/tlsr2018.29.1.6
    Red seaweed Gracilaria, one of the largest genus in Division Rhodophyta inhabits Sarawak coastal water. This study was designed to identify the species of Gracilaria using morphological approach and to assess selected water quality parameters in Gracilaria habitats. Three field samplings were carried out in Santubong and Asajaya, Sarawak from November 2013 to December 2014. Overall, three species were identified namely Gracilaria changii, G. blodgettii and G. coronopifolia, attached to net of cage culture in Santubong and root of mangrove trees in Asajaya. In addition, three different taxa of aquatic macroinvertebrates (polychaete, small crab, bivalve) and single species of red seaweed (Acanthophora sp.) were observed in Gracilaria assemblages. An estimate of 37% to 40% of the upper part of the cage net in Santubong was covered by seaweeds and only 16% to 20% in Asajaya's mangrove. The study had provided better information on identification of Gracilaria and their habitat in Sarawak. Future work involving DNA barcoding of each species is in progress.
    Matched MeSH terms: Gracilaria
  13. Chemical composition and physicochemical properties of tropical red seaweed, Gracilaria changii
    Chan PT, Matanjun P
    Food Chem, 2017 Apr 15;221:302-310.
    PMID: 27979207 DOI: 10.1016/j.foodchem.2016.10.066
    A study on the proximate composition, minerals, vitamins, carotenoids, amino acids, fatty acids profiles and some physicochemical properties of freeze dried Gracilaria changii was conducted. It was discovered that this seaweed was high in dietary fibre (64.74±0.82%), low in fat (0.30±0.02%) and Na/K ratio (0.12±0.02). The total amino acid content was 91.90±7.70% mainly essential amino acids (55.87±2.15mgg(-1)) which were comparable to FAO/WHO requirements. The fatty acid profiles were dominated by the polyunsaturated fatty acids particularly docosahexaenoic (48.36±6.76%) which led to low ω6/ω3, atherogenic, and thrombogenic index. The physicochemical properties of this seaweed namely the water holding and the swelling capacity were comparable to some commercial fibre rich products. This study suggested that G. changii could be potentially used as ingredients to improve nutritive value and texture of functional foods for human consumption.
    Matched MeSH terms: Gracilaria/chemistry*
  14. Fulltext Evaluation of the proximate, fatty acid and mineral composition of representative green, brown and red seaweeds from the Persian Gulf of Iran as potential food and feed resources
    Rohani-Ghadikolaei K, Abdulalian E, Ng WK
    J Food Sci Technol, 2012 Dec;49(6):774-80.
    PMID: 24293698 DOI: 10.1007/s13197-010-0220-0
    The proximate, fatty acid and mineral composition were determined for green (Ulva lactuca and Enteromorpha intestinalis), brown (Sargassum ilicifolium and Colpomenia sinuosa) and red (Hypnea valentiae and Gracilaria corticata) seaweeds collected from the Persian Gulf of Iran. Results showed that the seaweeds were high in carbohydrate (31.8-59.1%, dry weight) and ash (12.4-29.9%) but low in lipid content (1.5-3.6%). The protein content of red or green seaweeds was significantly higher (p 
    Matched MeSH terms: Gracilaria
  15. MOLECULAR CLONING AND BIOCHEMICAL CHARACTERIZATION OF GALACTOSE-1-PHOSPHATE URIDYLYLTRANSFERASE FROM GRACILARIA CHANGII (RHODOPHYTA)(1)
    Siow RS, Teo SS, Ho WY, Shukor MY, Phang SM, Ho CL
    J Phycol, 2012 Feb;48(1):155-62.
    PMID: 27009660 DOI: 10.1111/j.1529-8817.2011.01105.x
    Galactose-1-phosphate uridylyltransferase (GALT) catalyzes the reversible conversion of glucose-1-phosphate and UDP-galactose to galactose-1-phosphate and UDP-glucose. This enzyme is also responsible for one of the biochemical steps that produce the precursors of agar and agarose. In this study, we report the molecular cloning and sequence analyses of a cDNA encoding GALT, from Gracilaria changii (B. M. Xia et I. A. Abbott) I. A. Abbott, J. Zhang et B. M. Xia, which constitutes a genus of seaweeds that supply more than 60% of the world's agar and agarose. We have subcloned this cDNA into a bacterial expression cloning vector and characterized the enzyme activities of its recombinant proteins in vitro. The GcGALT gene was shown to be up-regulated by salinity stresses. The abundance of transcripts encoding GcGALT was the highest in G. changii, followed by Gracilaria edulis and Gracilaria salicornia in a descending order, corresponding to their respective agar contents. Our findings indicated that GALT could be one of the components that determines the agar yield in Gracilaria species.
    Matched MeSH terms: Gracilaria
  16. Global Transcriptome Analysis of Gracilaria changii (Rhodophyta) in Response to Agarolytic Enzyme and Bacterium
    Lim EL, Siow RS, Abdul Rahim R, Ho CL
    Mar Biotechnol (NY), 2016 Apr;18(2):189-200.
    PMID: 26631182 DOI: 10.1007/s10126-015-9680-6
    Many bacterial epiphytes of agar-producing seaweeds secrete agarase that degrade algal cell wall matrix into oligoagars which elicit defense-related responses in the hosts. The molecular defense responses of red seaweeds are largely unknown. In this study, we surveyed the defense-related transcripts of an agarophyte, Gracilaria changii, treated with β-agarase through next generation sequencing (NGS). We also compared the defense responses of seaweed elicited by agarase with those elicited by an agarolytic bacterium isolated from seaweed, by profiling the expression of defense-related genes using quantitative reverse transcription real-time PCR (qRT-PCR). NGS detected a total of 391 differentially expressed genes (DEGs) with a higher abundance (>2-fold change with a p value <0.001) in the agarase-treated transcriptome compared to that of the non-treated G. changii. Among these DEGs were genes related to signaling, bromoperoxidation, heme peroxidation, production of aromatic amino acids, chorismate, and jasmonic acid. On the other hand, the genes encoding a superoxide-generating NADPH oxidase and related to photosynthesis were downregulated. The expression of these DEGs was further corroborated by qRT-PCR results which showed more than 90 % accuracy. A comprehensive analysis of their gene expression profiles between 1 and 24 h post treatments (hpt) revealed that most of the genes analyzed were consistently upregulated or downregulated by both agarase and agarolytic bacterial treatments, indicating that the defense responses induced by both treatments are highly similar except for genes encoding vanadium bromoperoxidase and animal heme peroxidase. Our study has provided the first glimpse of the molecular defense responses of G. changii to agarase and agarolytic bacterial treatments.
    Matched MeSH terms: Gracilaria
  17. Fulltext Nutritional composition and amino acid profile of a sub-tropical red seaweed Gelidium pusillum collected from St. Martin’s Island, Bangladesh
    Siddique, M.A.M., Khan, M.S.K., Bhuiyan, M.K.A.
    International Food Research Journal, 2013;20(5):2287-2292.
    MyJurnal
    Nutritional fact study has prime importance to make the species edible and commercially viable to the food consumers. The proximate chemical composition and amino acid profile of Gelidium pusillum were studied to understand the nutritional status. The red seaweed Gelidium pusillum was rich in dietary fibre (24.74 ± 1.05%), lipid (2.16 ± 0.61%) and ash content (21.15 ± 0.74%). The mean protein content (11.31 ± 1.02% DW) was within the range of 10-47% for green and red seaweeds and this range was higher than Gracilaria cornea (5.47% DW), Gracilaria changgi (6.90% DW) and Eucheuma cottonii (9.76% DW). Gelidium pusillum was found to contained all the essential amino acids, which accounted for 52.08% of the total amino acids. Tyrosine (26.2 mg g-1 protein), methionine (15.8 mg g-1 protein) and Lysine (48.3 mg g-1 protein) were the limiting amino acid of Gelidium pusillum. However, the levels of other essential amino acids were above the FAO/WHO requirement pattern (EAA score ranged from 1.14 to 1.62). Aspartic and glutamic acids constituted a substantial amount of the total amino acids (24.68% of total amino acid). The result from this study suggested that Gelidium pusillum could be utilized as a healthy food item for human consumption.
    Matched MeSH terms: Gracilaria
  18. Fulltext Transcriptome profiling of sulfate deprivation responses in two agarophytes Gracilaria changii and Gracilaria salicornia (Rhodophyta)
    Lee WK, Namasivayam P, Ong Abdullah J, Ho CL
    Sci Rep, 2017 04 24;7:46563.
    PMID: 28436444 DOI: 10.1038/srep46563
    Seaweeds survive in marine waters with high sulfate concentration compared to those living at freshwater habitats. The cell wall polymer of Gracilaria spp. which supplies more than 50% of the world agar is heavily sulfated. Since sulfation reduces the agar quality, it is interesting to investigate the effects of sulfate deprivation on the sulfate contents of seaweed and agar, as well as the metabolic pathways of these seaweeds. In this study, two agarophytes G. changii and G. salicornia were treated under sulfate deprivation for 5 days. The sulfate contents in the seaweed/agar were generally lower in sulfate-deprivated samples compared to those in the controls, but the differences were only statistically significant for seaweed sample of G. changii and agar sample of G. salicornia. RNA sequencing (RNA-Seq) of sulfate-deprivated and untreated seaweed samples revealed 1,292 and 3,439 differentially expressed genes (DEGs; ≥1.5-fold) in sulfate-deprivated G. changii and G. salicornia, respectively, compared to their respective controls. Among the annotated DEGs were genes involved in putative agar biosynthesis, sulfur metabolism, metabolism of sulfur-containing amino acids, carbon metabolism and oxidative stress. These findings shed light on the sulfate deprivation responses in agarophytes and help to identify candidate genes involved in agar biosynthesis.
    Matched MeSH terms: Gracilaria
  19. Fulltext Effects of Seasonal Variability on the Physicochemical, Biochemical, and Nutritional Composition of Western Peninsular Malaysia Gracilaria manilaensis
    Aroyehun AQ, Palaniveloo K, Ghazali F, Rizman-Idid M, Abdul Razak S
    Molecules, 2019 Sep 10;24(18).
    PMID: 31510066 DOI: 10.3390/molecules24183298
    This study evaluated the effect of seasonal variation on the physicochemical, biochemical, and nutritional composition of Gracilaria manilaensis. Sampling was designed during the main monsoon seasons in Malaysia-the Southwest monsoon (SWM) and Northeast monsoon (NEM)-to understand the intraspecific variation (p < 0.05). Carbohydrates, protein, and dietary fiber were found to be higher in NEM-G. manilaensis, whereas a higher ash content was quantified in SWM-G. manilaensis. No significant differences were found in crude lipid and moisture content (p > 0.05). Vitamin B2 was calculated as (0.29 ± 0.06 mg 100 g-1) and (0.38 ± 0.06 mg 100 g-1) for the NEM and SWM samples, respectively (p < 0.05). The fatty acid profile showed the dominance of saturated fatty acids (SFAs)-palmitic acids, stearic acid, and myristic acid-while the mineral contents were found to be good sources of calcium (1750.97-4047.74 mg 100 g-1) and iron (1512.55-1346.05 mg 100 g-1). Tryptophan and lysine were recorded as the limiting essential amino acids (EAAs) in NEM G. manilaensis, while leucine and phenylalanine were found to be the limiting EAAs in the SWM samples. None of the extracts exhibited antibacterial properties against the screened strains. The study concluded that seasonal changes have a great effect on the biochemical composition of G. manilaensis.
    Matched MeSH terms: Gracilaria/chemistry*
  20. In vitro antimicrobial activity against Pseudomonas aeruginosa and acute oral toxicity of marine algae Gracilaria changii
    Sasidharan S, Darah I, Noordin MK
    N Biotechnol, 2010 Sep 30;27(4):390-6.
    PMID: 20170762 DOI: 10.1016/j.nbt.2010.02.002
    Methanol extract of the Gracilaria changii has been screened for antimicrobial activity against Pseudomonas aeruginosa. Antimicrobial activities were carried out using disc diffusion assay and broth dilution method against P. aeruginosa. The methanol extract of G. changii showed a good antimicrobial activity against P. aeruginosa with MIC (Minimum Inhibitory Concentration) value of 6.25mg/ml. Exposure of P. aeruginosa cells to 6.25mg/ml of methanol extract of G. changii resulted in complete inhibition of the bacterial cells. The main abnormalities noted via SEM and TEM studies were the alterations in morphology and cytology of the bacterial cells. The main reason for this deterioration was discussed. The effect of the methanol extract on the growth profile for the bacteria was also done and confirmed the bactericidal effect of the G. changii methanol extract on P. aeruginosa by changing the normal growth profile of P. aeruginosa. In an acute toxicity study using mice, the median lethal dose (LD(50)) of the extract was greater than 2000 mg/kg, and we found no pathological changes in macroscopic examination by necropsy of mice treated with extract. We conclude that G. changii might be safely used as an antimicrobial agent.
    Matched MeSH terms: Gracilaria/chemistry*
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