Displaying publications 61 - 80 of 120 in total

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  1. 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: Brachyura
  2. The Feeding Ecology of the Blue Swimming Crab, Portunus pelagicus (Linnaeus, 1758), at Kung Krabaen Bay, Chanthaburi Province, Thailand
    Kunsook C, Gajaseni N, Paphavasit N
    Trop Life Sci Res, 2014 Aug;25(1):13-27.
    PMID: 25210585
    The natural diet of blue swimming crabs, Portunus pelagicus, was investigated from October 2008 to October 2009 using hand sampling and a crab gill net. The results showed that the major prey items in the stomach contents of P. pelagicus were teleost fish (29.61%), organic matter (20.69%), crustaceans (18.3%) and shelled molluscs (11.46%). Significant differences were found in diet composition between juvenile and mature crabs, between crabs inside and outside the bay and among seasons. In contrast, significant differences were not found between male and female crabs.
    Matched MeSH terms: Brachyura
  3. Possible food sources of macrozoobenthos in the manko mangrove ecosystem, okinawa (Japan): a stable isotope analysis approach
    Wardiatno Y, Mardiansyah, Prartono T, Tsuchiya M
    Trop Life Sci Res, 2015 Apr;26(1):53-65.
    PMID: 26019747
    Identifying potential food sources in mangrove ecosystems is complex because of the multifarious inputs from both land and sea. This study, which was conducted in the Manko mangrove ecosystem of Okinawa, Japan, determined the composition of the stable isotopes δ(13)C and δ(15)N in primary producers and macrozoobenthos to estimate the potential food sources assimilated and to elucidate the target trophic levels of the macrozoobenthos. We measured the two stable isotope signatures of three gastropods (Cerithidea sp., Cassidula mustelina, Peronia verruculata), two crabs (Grapsidae sp., Uca sp.), mangrove tree (Kandelia candel) leaves, and sediment from the mangrove ecosystem. The respective carbon and nitrogen isotope signature results were as follows: -22.4‰ and 8.6‰ for Cerithidea sp., -25.06‰ and 8‰ for C. mustelina, -22.58‰ and 8‰ for P. verruculata, -24.3‰ and 10.6‰ for unidentified Grapsidae, -21.87 ‰ and 11.5 ‰ for Uca sp., -29.81‰ and 11‰ for K. candel, and -24.23‰ and 7.2‰ for the sediment. The stable isotope assimilation signatures of the macrozoobenthos indicated sediment as their food source. Considering the trophic levels, the stable isotope values may also indicate that the five macrozoobenthos species were secondary or higher consumers.
    Matched MeSH terms: Brachyura
  4. Fulltext The final spawning ground of Tachypleus gigas (Müller, 1785) on the east Peninsular Malaysia is at risk: a call for action
    Nelson BR, Satyanarayana B, Moh JHZ, Ikhwanuddin M, Chatterji A, Shaharom F
    PeerJ, 2016;4:e2232.
    PMID: 27547542 DOI: 10.7717/peerj.2232
    Tanjung Selongor and Pantai Balok (State Pahang) are the only two places known for spawning activity of the Malaysian horseshoe crab - Tachypleus gigas (Müller, 1785) on the east coast of Peninsular Malaysia. While the former beach has been disturbed by several anthropogenic activities that ultimately brought an end to the spawning activity of T. gigas, the status of the latter remains uncertain. In the present study, the spawning behavior of T. gigas at Pantai Balok (Sites I-III) was observed over a period of thirty six months, in three phases, between 2009 and 2013. Every year, the crab's nesting activity was found to be high during Southwest monsoon (May-September) followed by Northeast (November-March) and Inter monsoon (April and October) periods. In the meantime, the number of female T. gigas in 2009-2010 (Phase-1) was higher (38 crabs) than in 2010-2011 (Phase-2: 7 crabs) and 2012-2013 (Phase-3: 9 crabs) for which both increased overexploitation (for edible and fishmeal preparations) as well as anthropogenic disturbances in the vicinity (sand mining since 2009, land reclamation for wave breaker/parking lot constructions in 2011 and fishing jetty construction in 2013) are responsible. In this context, the physical infrastructure developments have altered the sediment close to nesting sites to be dominated by fine sand (2.5Xφ ) with moderately-well sorted (0.6-0.7σφ), very-coarse skewed (-2.4SKφ), and extremely leptokurtic (12.6Kφ) properties. Also, increased concentrations of Cadmium (from 4.2 to 13.6 mg kg(-1)) and Selenium (from 11.5 to 23.3 mg kg(-1)) in the sediment, and Sulphide (from 21 to 28 µg l(-1)) in the water were observed. In relation to the monsoonal changes affecting sheltered beach topography and sediment flux, the spawning crabs have shown a seasonal nest shifting behaviour in-between Sites I-III during 2009-2011. However, in 2012-2013, the crabs were mostly restricted to the areas (i.e., Sites I and II) with high oxygen (5.5-8.0 mg l(-1)) and moisture depth (6.2-10.2 cm). In view of the sustained anthropogenic pressure on the coastal habitats on one hand and decreasing horseshoe crabs population on the other, it is crucial to implement both conservation and management measures for T. gigas at Pantai Balok. Failing that may lead to the loss of this final spawning ground on the east coast of P. Malaysia.
    Matched MeSH terms: Brachyura
  5. Species delimitation of crab-eating frogs (Fejervarya cancrivora complex) clarifies taxonomy and geographic distributions in mainland Southeast Asia
    Yodthong S, Stuart BL, Aowphol A
    Zookeys, 2019;883:119-153.
    PMID: 31719776 DOI: 10.3897/zookeys.883.37544
    The taxonomy and geographic distributions of species of crab-eating frogs (Fejervarya cancrivora complex) in mainland Southeast Asia have been highly uncertain. Three taxonomic names are used in recent literature (F. cancrivora, F. raja, and F. moodiei) but the applications of these names to localities has been inconsistent, especially owing to the lack of available molecular data for F. raja. Morphometric and mitochondrial DNA variation was examined in these frogs, including name-bearing types and topotypes of all three species. Findings corroborate evidence for the existence of two species in coastal mainland Southeast Asia, with F. moodiei having a wide geographic distribution and F. cancrivora sensu stricto occurring only in extreme southern Thailand and peninsular Malaysia. Fejervarya raja is shown to be only a large-bodied population of F. cancrivora sensu stricto and is synonymized with that species. Revised descriptions of F. moodiei and F. cancrivora sensu stricto are provided.
    Matched MeSH terms: Brachyura
  6. Fulltext Morphological descriptions and morphometric discriminant function analysis reveal an additional four groups of Scylla spp
    Fazhan H, Waiho K, Quinitio E, Baylon JC, Fujaya Y, Rukminasari N, et al.
    PeerJ, 2020;8:e8066.
    PMID: 31915566 DOI: 10.7717/peerj.8066
    There are four species of mud crabs within the genus Scylla, and most of them live sympatrically in the equatorial region. Apart from a report in Japan about the finding of a natural Scylla hybrid more than a decade ago after the division of genus Scylla into four species by Keenan, Davie & Mann (1998), no subsequent sighting was found. Thus, this study investigates the possible natural occurrence of potential hybridization among Scylla species in the wild. A total of 76,211 individuals from mud crab landing sites around the Malacca Straits, South China Sea and Sulu Sea were screened. In addition to the four-purebred species, four groups (SH 1, n = 2, 627; SH 2, n = 136; SH 3, n = 1; SH 4, n = 2) with intermediate characteristics were found, mostly at Sulu Sea. Discriminant Function Analysis revealed that all Scylla species, including SH 1 - 4, are distinguishable via their morphometric ratios. The most powerful discriminant ratios for each character and the top five discriminant ratios of males and females were suggested. The carapace width of SH 1 males and females were significantly smaller than pure species. Based on the discriminant ratios and the description of morphological characters, we hypothesize that the additional four groups of Scylla with intermediate characteristics could be presumed hybrids. Future work at the molecular level is urgently needed to validate this postulate.
    Matched MeSH terms: Brachyura
  7. Fulltext Behavioural data on instar crab movement at different thermal acclimation
    Azra MN, Ikhwanuddin M, Abol-Munafi AB
    Data Brief, 2019 Feb;22:998-1002.
    PMID: 30740484 DOI: 10.1016/j.dib.2019.01.026
    This article investigated how crabs responded to different culture temperatures especially dislocation before molting using a combination of large recording files and computer software. In this novel approach of video recording portunid crab behavioral data, crab culture was recorded at five different acclimation temperatures of 20, 24, 28, 32 and 36 °C. Crabs were reared until the instar stage before being acclimatized for video recording. Large video files (MPEG-TS) were then analyzed using the latest version of Solomon Coder software developed by A. Peter and programmed with Embarcadero® Delphi® XE [1]. Recorded data was analyzed by calculating and marking movements of crabs using the time sequence tool. Additionally, a total movement was counted 30 min before crabs molted from instar stage 8 to instar stage 9. Part of the data is associated with the research article "Thermal tolerance and locomotor activity of blue swimmer crab Portunus pelagicus instar reared at different temperatures" (Azra et al., 2018) [2] and provided here as raw data of Supplementary materials.
    Matched MeSH terms: Brachyura
  8. Fulltext Geometric morphometric analysis in female freshwater crabs of Sarawak (Borneo) permits addressing taxonomy-related problems
    Grinang J, Das I, Ng PKL
    PeerJ, 2019;7:e6205.
    PMID: 30783559 DOI: 10.7717/peerj.6205
    The taxonomy of freshwater crabs requires a paradigm change in methodological approaches, particularly in investigations that use morphological techniques. The traditional morphometric approach (two-dimensional measurements) tends to be inappropriate for the identification of freshwater crabs due to their variable external morphology and lack of gonopods (conventionally used for the identification of male crabs) in females. In this study, we explore the potential use of the geometric morphometric technique for identification of female freshwater crabs, and identify taxonomic key characteristics of species. The shape of the carapace could be a good characteristic for the identification of female crabs, especially when the geometric morphometric technique is used. It was observed that the shape of the carapace has an advantage over the shape of the pleon and chela because its relatively flat orientation allows more consistent and easier data preparation for geometric morphometric analysis. The geometric morphometric technique is inexpensive, relatively less time consuming to employ, and accurate. This technique is convenient when dissection to examine the gonopods is not possible, which can damage the specimen in the case of endangered or rare species. Since the technique was used herein for only two species, more compelling and extensive evidence is needed before the reliability of the method can be proven.
    Matched MeSH terms: Brachyura
  9. Fulltext The adsorption of reactive orange 16 and basic blue 3 from aqueous solution using quaternized blue swimmer crab carapace
    Chuah, Y.J., Tan, Y.P., Abdullah, H.A.
    Pertanika Journal of Science & Technology, 2018;26(4):2045-2062.
    MyJurnal
    The crab carapace is a waste which cannot be decomposed. This waste was used to
    remove the Reactive Orange 16 (RO16) and Basic Blue 3 (BB3) from aqueous solution
    at different operational parameters such as pH, mass load, the concentrations of dye and
    the temperature. The crab collected was modified to obtain quaternized crab (QC) using
    (3-chloro-2-hydroxypropyl) trimethylammonium chloride solution (C6H15Cl2NO, 65% w/w
    in water). The pH of the dyes solution was varied from pH 4 to 10. The highest adsorption
    percentage was achieved at pH 7 for both dyes. Increasing the QC mass for the adsorption
    process had granted an increase of dyes removal percentage. The highest adsorption
    percentage was achieved at 91.00% for RO16 and 29.40% for BB3 dyes with 7.5 g/L QC
    used. However, the adsorption capacity of QC decreased with higher QC mass because the
    dye molecules occupied on the surface and prevented other molecules to diffuse into the
    QC. At higher concentration beyond 20 mg/L and 10 mg/L of RO16 and BB3, respectively,
    the maximum adsorption was achieved at 2.5362 mg/g and 0.6812 mg/g. The adsorption of
    both dyes by QC was best fitted using Langmuir isotherm model, explaining the adsorption
    mainly occurred as a single layer on the surface of QC. Comparison to the results obtained
    from the kinetic models, the adsorption was
    chemisorption in nature. According to the
    thermodynamic studies, the adsorption of
    RO16 was an exothermic, while BB3 was
    an endorthermic process.
    Matched MeSH terms: Brachyura
  10. Fulltext Reassessment of species distribution and occurrence of mud crab (Scylla spp., Portunidae) in Malaysia through morphological and molecular identification
    Naim DM, Nor SAM, Mahboob S
    Saudi J Biol Sci, 2020 Feb;27(2):643-652.
    PMID: 32210683 DOI: 10.1016/j.sjbs.2019.11.030
    This study utilized genetic and morphometric approaches to assess the molecular and morphometric differentiation among commercially important species of mud crab. Molecular investigations were derived from 542 bp mitochondrial DNA COI on 249 individuals within genus Scylla from nine states in Malaysia represents four marine regions; South China Sea, Sulu Sea, Straits of Singapore and Straits of Malacca. Four specimens were obtained from Indonesia to give a robust analysis in this study. For species delimitation, Automatic Barcode Gap Discovery (ABGD) method on a web interface was employed. Analysis on phylogenetics was implemented utilizing Neighbour joining (NJ) and Maximum Parsimony (MP) methods. The inter- and intraspecies genetic distances (Ds ) was computed using Kimura 2-parameter distance and executed in MEGA version 5.05. All samples were genetically and morphologically identified and clustered into four distinct species. Among the species, S. olivacea was the most abundant (n = 111), on the other hand the occurrence of S. paramamosain in Malaysia was very low (n = 29). No single individual of S. serrata from Malaysia was recorded in this study. Both genetic distance and phylogenetic approaches exhibited a correlative monophyletic association among all specimens analysed. This present study is crucial as it reports the reassessment of all species within genus Scylla in Malaysia, eventually could be employed as a reference source for subsequent research mainly on mariculture and other conservation efforts for the species.
    Matched MeSH terms: Brachyura
  11. Salangathelphusa peractio, a new species of lowland freshwater crab from Pulau Langkawi, Peninsular Malaysia (Crustacea, Brachyura, Gecarcinucidae)
    Ng PKL
    Zookeys, 2017.
    PMID: 29134027 DOI: 10.3897/zookeys.711.20621
    A new species of lowland freshwater crab of the family Gecarcinucidae, Salangathelphusa peractio, is described from Langkawi, an island off the northwestern coast of peninsular Malaysia. Salangathelphusa peractiosp. n. can be separated from S. brevicarinata (Hilgendorf, 1882) in having a proportionately broader external orbital tooth, a distinctly concave posterolateral margin, and the terminal segment of the male first gonopod is not distinctly bent laterally outwards; and from S. anophrys (Kemp, 1923) by its more quadrate carapace and the terminal segment of the male first gonopod possessing a relatively longer and less curved distal part. This is sixth wholly freshwater brachyuran species known from the island.
    Matched MeSH terms: Brachyura
  12. The complete mitogenome of purple mottled shore crab Cyclograpsus granulosus H. Milne-Edwards, 1853 (Crustacea: Decapoda: Grapsoidea)
    Tan MH, Gan HM, Lee YP, Austin CM
    Mitochondrial DNA A DNA Mapp Seq Anal, 2016 11;27(6):3981-3982.
    PMID: 25541307
    The mitochondrial genome sequence of the purple mottled shore crab, Cyclograpsus granulosus, is documented (GenBank accession number: LN624373), which makes it the third for genera of the superfamily Grapsoidea. Cyclograpsus granulosus has a mitogenome of 16,300 bp consisting of 13 protein-coding genes, two ribosomal subunit genes, 22 transfer RNAs and a non-coding AT-rich region. The base composition of the C. granulosus mitogenome is 36.15% for T, 19.54% for C, 33.14% for A and 11.17% for G, with an AT bias of 69.29%. The mitogenome gene order is atypical for the brachyuran crabs, but is identical to species of the genus Eriocheir from the same family.
    Matched MeSH terms: Brachyura/genetics*
  13. Mitochondrial DNA diversity of mud crab Scylla olivacea (Portunidae) in Peninsular Malaysia: a preliminary assessment
    Rosly HA, Nor SA, Yahya K, Naim DM
    Mol Biol Rep, 2013 Nov;40(11):6407-18.
    PMID: 24062076 DOI: 10.1007/s11033-013-2755-4
    A primary factor in population management and wildlife conservation is the delineation of population units derived from descriptions of population genetic structure. Yet, predicting factors that influence the patterns of gene flow in a population particularly at landscape scales remains a major challenge in evolutionary biology. Here we report a population genetic study of the mud crab Scylla olivacea examined based on a 542 bp segment of the mitochondrial DNA cytochrome c oxidase I gene among 91 individuals from six localities in the west and east coast of Peninsular Malaysia. In total 55 unique haplotypes were distinguished with 45 private haplotypes and a single common haplotype shared among all populations studied. The other ten haplotypes were shared among various populations. The sharing of this haplotype reflects the connection of the mangrove areas between east and west coast of Peninsular Malaysia. High haplotype diversity (h = 0.968 ± 0.021; mean ± SD) and low nucleotide diversity (π = 0.120 ± 0.015; mean ± SD) were displayed, which may be indicative of genetic bottleneck events. No significant phylogenetic lineages were recognized using neighbour-joining and maximum parsimony methods. Hierarchical AMOVA analysis indicated that 99.33 % of the genetic variation was contained within populations and 0.67 % occurred among populations, suggesting no geographical patterning among populations studied, supported by F st test. Mismatch distribution analysis showed that the observed distribution of the pairwise mutation differences among haplotypes was multimodal, which is not concordant with a sudden range expansion scenario. However, neutrality tests showed non-significant negative values suggesting that the populations studied may have experienced past population growth, but the expansion may have been restricted to separate local areas that resulted in the non-significant negative Fu's Fs and Tajima's D value. Overall, this present preliminary study was able to be a reference on the phylogenetic relationships and assessment of genetic structure of Scylla sp. in Malaysia.
    Matched MeSH terms: Brachyura/genetics*
  14. Larval development of the pedunculate barnacles Octolasmis angulata Aurivillius 1894 and Octolasmis cor Aurivillius 1892 (Cirripedia: Thoracica: Poecilasmatidae) from the gills of the mud crab, Scylla tranquebarica Fabricius, 1798
    Yap FC, Wong WL, Maule AG, Brennan GP, Lim LH
    Arthropod Struct Dev, 2015 May;44(3):253-79.
    PMID: 25770075 DOI: 10.1016/j.asd.2015.02.001
    Detailed studies of larval development of Octolasmis angulata and Octolasmis cor are pivotal in understanding the larval morphological evolution as well as enhancing the functional ecology. Six planktotrophic naupliar stages and one non-feeding cyprid stage are documented in details for the first time for the two species of Octolasmis. Morphologically, the larvae of O. angulata and O. cor are similar in body size, setation patterns on the naupliar appendages, labrum, dorsal setae-pores, frontal horns, cyprid carapace, fronto-lateral gland pores, and lattice organs. Numbers of peculiarities were observed on the gnathobases of the antennae and mandible throughout the naupliar life-cycle. The setation pattern on the naupliar appendages are classified based on the segmentation on the naupliar appendages. The nauplius VI of both species undergoes a conspicuous change before metamorphosis into cyprid stage. The cyprid structures begin to form and modify beneath the naupliar body towards the end of stage VI. This study emphasises the importance of the pedunculate barnacle larval developmental studies not only to comprehend the larval morphological evolution but also to fill in the gaps in understanding the modification of the naupliar structures to adapt into the cyprid life-style.
    Matched MeSH terms: Brachyura/physiology
  15. Bioaccumulation of trace metals in the coastal Borneo (Malaysia) and health risk assessment
    Anandkumar A, Nagarajan R, Prabakaran K, Bing CH, Rajaram R, Li J, et al.
    Mar Pollut Bull, 2019 Aug;145:56-66.
    PMID: 31590824 DOI: 10.1016/j.marpolbul.2019.05.002
    The concentration of nine trace elements were analyzed in the different tissue organs of commonly available crabs (Portunus sanguinolentus, Portunus pelagicus and Scylla serrate) and bivalve (Polymesoda erosa) species collected from the Miri coast, Borneo in order to evaluate the potential health risk by consumption of these aquatic organisms. Among the analyzed organs, metal accumulation was higher in the gill tissues. The essential (Cu and Zn) and non-essential (Pb and Cd) elements showed the highest (i.e. Zn) and lowest concentrations (i.e. Cd) in their tissue organs, respectively. The estimated daily intake and hazard indices of all metals in the muscle indicate that the measured values were below the provisional tolerable daily intake suggested by the joint FAO/WHO Expert Committee on Food Additives. Compared to Malaysian and international seafood guideline values the results obtained from the present study are lower than the permissible limits and safe for consumption.
    Matched MeSH terms: Brachyura/metabolism*
  16. Identification of male-specific SNP markers and development of PCR-based genetic sex identification technique in crucifix crab (Charybdis feriatus) with implication of an XX/XY sex determination system
    Fang S, Zhang Y, Shi X, Zheng H, Li S, Zhang Y, et al.
    Genomics, 2020 01;112(1):404-411.
    PMID: 30851358 DOI: 10.1016/j.ygeno.2019.03.003
    In this study, we first identified male-specific SNP markers using restriction site-associated DNA sequencing, and further developed a PCR-based sex identification technique for Charybdis feriatus. A total of 296.96 million clean reads were obtained, with 114.95 and 182.01 million from females and males. After assembly and alignment, 10 SNP markers were identified being heterozygous in males but homozygous in females. Five markers were further confirmed to be male-specific in a large number of individuals. Moreover, two male-specific sense primers and a common antisense primer were designed, using which, a PCR-based genetic sex identification method was successfully developed and used to identify the sex of 103 individuals, with a result of 49 females and 54 males. The presence of male-specific SNP markers suggests an XX/XY sex determination system for C. feriatus. These findings should be helpful for better understanding sex determination mechanism, and drafting artificial breeding program in crustaceans.
    Matched MeSH terms: Brachyura/genetics*
  17. Fulltext In vitro Inhibitory Effects of Two Bornean Medicinal Wild Gingers against Pathogenic Lagenidium thermophilum Infected Mud Crab Scylla tranquebarica
    Hatai K, Kamada T, Lau LM, Kulip J, Phan CS, Vairappan CS
    Biocontrol Sci, 2018;23(1):35-39.
    PMID: 29576593 DOI: 10.4265/bio.23.35
    　The antifungal activity of two Bornean medicinal wild gingers Plagiostachys megacarpa and Zingiber phillippsiae were examined against Lagenidium thermophilum. The most active extract was P. megacarpa at concentration of 320 µg/mL inhibiting both hyphal growth and zoospore production of L. thermophilum in 24 h. Toxicity tests were conducted using mud crab (Scylla tranquebarica) larva. Bath treatment of P. megacarpa at concentrations of 320 and 640 µg/mL for 24 h were highly effective against hyphae and zoospores of the strain and it is non-toxic to mud crab larva. Therefore, crude extracts P. megacarpa may be used as alternative treatment for marine Oomycete infection of mud crab.
    Matched MeSH terms: Brachyura/microbiology*
  18. Molecular and allergenic characterization of recombinant tropomyosin from mud crab Scylla olivacea
    Azemi NFH, Misnan R, Keong BP, Mokhtar M, Kamaruddin N, Fah WC, et al.
    Mol Biol Rep, 2021 Oct;48(10):6709-6718.
    PMID: 34427887 DOI: 10.1007/s11033-021-06661-x
    BACKGROUND: Tropomyosin is a major allergen in crustaceans, including mud crab species, but its molecular and allergenic properties in Scylla olivacea are not well known. Thus, this study aimed to produce the recombinant tropomyosin protein from S. olivacea and subsequently investigate its IgE reactivity.

    METHODS AND RESULTS: The tropomyosin gene was cloned and expressed in the Escherichia coli system, followed by SDS-PAGE and immunoblotting test to identify the allergenic potential of the recombinant protein. The 855-base pair of tropomyosin gene produced was found to be 99.18% homologous to Scylla serrata. Its 284 amino acids matched the tropomyosin of crustaceans, arachnids, insects, and Klebsiella pneumoniae, ranging from 79.03 to 95.77%. The tropomyosin contained 89.44% alpha-helix folding with a tertiary structure of two-chain alpha-helical coiled-coil structures comprising a homodimer heptad chain. IPTG-induced histidine tagged-recombinant tropomyosin was purified at the size of 42 kDa and confirmed as tropomyosin using anti-tropomyosin monoclonal antibodies. The IgE binding of recombinant tropomyosin protein was reactive in 90.9% (20/22) of the sera from crab-allergic patients.

    CONCLUSIONS: This study has successfully produced an allergenic recombinant tropomyosin from S. olivacea. This recombinant tropomyosin may be used as a specific allergen for the diagnosis of allergy.

    Matched MeSH terms: Brachyura/immunology*
  19. Leucoxenols A and B, two new phenolics from Bornean medicinal plant Syzygium leucoxylon
    Shamsudin KJ, Phan CS, Kulip J, Hatai K, Vairappan CS, Kamada T
    J Asian Nat Prod Res, 2019 May;21(5):435-441.
    PMID: 29502443 DOI: 10.1080/10286020.2018.1440391
    The medicinal plant, Syzygium leucoxylon or commonly known as Obah found in North Borneo was considered as traditional medicine by local committee. Two new phenolics, leucoxenols A (1) and B (2) were isolated and identified as major secondary metabolites from the leaves of S. leucoxylon. Their chemical structures were elucidated based on spectroscopic data such as NMR and HRESIMS. Furthermore, these compounds were active against selected strains of fungi.
    Matched MeSH terms: Brachyura/drug effects
  20. Transcriptome-seq provides insights into sex-preference pattern of gene expression between testis and ovary of the crucifix crab ( Charybdis feriatus)
    Zhang Y, Miao G, Fazhan H, Waiho K, Zheng H, Li S, et al.
    Physiol Genomics, 2018 05 01;50(5):393-405.
    PMID: 29570432 DOI: 10.1152/physiolgenomics.00016.2018
    The crucifix crab, Charybdis feriatus, which mainly inhabits Indo-Pacific region, is regarded as one of the most high-potential species for domestication and incorporation into the aquaculture sector. However, the regulatory mechanisms of sex determination and differentiation of this species remain unclear. To identify candidate genes involved in sex determination and differentiation, high throughput sequencing of transcriptome from the testis and ovary of C. feriatus was performed by the Illumina platform. After removing adaptor primers, low-quality sequences and very short (<50 nt) reads, we obtained 80.9 million and 66.2 million clean reads from testis and ovary, respectively. A total of 86,433 unigenes were assembled, and ~43% (37,500 unigenes) were successfully annotated to the NR, NT, Swiss-Prot, KEGG, COG, GO databases. By comparing the testis and ovary libraries, we obtained 27,636 differentially expressed genes. Some candidate genes involved in the sex determination and differentiation of C. feriatus were identified, such as vasa, pgds, vgr, hsp90, dsx-f, fem-1, and gpr. In addition, 88,608 simple sequence repeats were obtained, and 61,929 and 77,473 single nucleotide polymorphisms from testis and ovary were detected, respectively. The transcriptome profiling was validated by quantitative real-time PCR in 30 selected genes, which showed a good consistency. The present study is the first high-throughput transcriptome sequencing of C. feriatus. These findings will be useful for future functional analysis of sex-associated genes and molecular marker-assisted selections in C. feriatus.
    Matched MeSH terms: Brachyura/genetics*
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