The incidence of Vibrio parahaemolyticus in products of the Malaysian export shrimp processing industry was investigated through the stages from the catch to that of the cooked, peeled and frozen product. The organism was commonly found in freshly caught and landed shrimp, and could be detected by enrichment culture at all stages of processing. The number of V. parahaemolyticus in shrimp varied from nil to 4x10(4), and 19 of the 50 serotypes in the current antigenic scheme were found, O1-K38 and O1-K32 occurring most often. All the isolates were Kanagawa-negative; one strain was a sucrose-positive variant. The study indicated that specifications of 10(2) g-1 for V. parahaemolyticus in raw tropical shellfish are too stringent but that the Malaysian shrimp industry should be able to meet this requirement for cooked shrimp.
Crude extracts (methanol) of various parts, viz. the leaves, fruits, roots, stem and trunk bark, of Garcinia atroviridis were screened for antimicrobial, cytotoxic, brine shrimp toxic, antitumour-promoting and antioxidant activities. The crude extracts exhibited predominantly antibacterial activity with the root extract showing the strongest inhibition against the test bacteria at a minimum inhibitory dose (MID) of 15.6 microg/disc. Although all the extracts failed to inhibit the growth of most of the test fungi, significant antifungal activity against Cladosporium herbarum was exhibited by most notably the fruit (MID: 100 microg), and the leaf (MID: 400 microg) extracts. None of the extracts were significantly cytotoxic, and lethal towards brine shrimps. The root, leaf, trunk and stem bark extracts (except for the fruits) showed strong antioxidant activity exceeding that of the standard antioxidant, alpha-tocopherol. Antitumour-promoting activity (>95% inhibition) was shown by the fruit, leaf, stem and trunk bark extracts.
The significance of food specific serum IgG4 antibody in food allergy is unclear and this led us to investigate the relevance of specific IgG4, along with IgG and IgE antibodies to two common food allergens in Malaysia. Enzyme-linked immunosorbent assay (ELISA) was used to measure the serum antibodies in 143 allergic rhinitis patients' sera, of which 47 were from patients with clinical indication of shrimp allergy, 46 with clinical indication of crab allergy and 50 without indication to either allergy. Clinical indication of allergy was based on answers to a questionnaire or results of the skin prick test. We found that the elevation of specific IgE or IgG4 is associated with shrimp and crab allergies but elevation of specific IgG is not associated with either allergy. However, the clinical utility of elevated specific IgG and IgG4 levels is pending further investigation.
Study site: Allergic rhinitis clinic, University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia
The vp28 gene encoding an envelope protein (28 kDa) of white spot syndrome virus (WSSV) was amplified from WSSV-infected tiger shrimp that originated from Malaysia. Recombinant VP28 protein (r-28) was expressed in Escherichia coli and used as an antigen for preparation of monoclonal antibodies (MAbs). Three murine MAbs (6F6, 6H4 and 9C10) that were screened by r-28 antigen-based enzyme-linked immunosorbent assay (ELISA) were also able to recognize viral VP28 protein as well as r-28 on Western blot. Three non-overlapping epitopes of VP28 protein were determined using the MAbs in competitive ELISA; thus, an antigen-capture ELISA (Ac-ELISA) was developed by virtue of these MAbs. Ac-ELISA can differentiate WSSV-infected shrimp from uninfected shrimp and was further confirmed by a polymerase chain reaction (PCR) and Western blot. Approximately 400 pg of purified WSSV sample and 20 pg of r-28 could be detected by Ac-ELISA, which is comparable in sensitivity to PCR assay but more sensitive than Western blot in the detection of purified virus. Hemolymph and tissue homogenate samples collected from a shrimp farm in Malaysia during December 2000 and July 2001 were also detected by Ac-ELISA and PCR with corroborating results.
Detection of diatom frustules in bone marrow (diatom test) is used for diagnosing ante-mortem drowning where the usual signs of drowning are not present in dead bodies recovered from water. However, controversies over the reliability of diatom test results are continuing. There have been indications on the possibilities of diatoms entering into systemic circulation from atmospheric air, food and drink. While diatoms have been demonstrated in the gut content of edible marine forms such as shrimps and clams, the present study, for the first time, provides empirical evidence on the prevalence as well as abundance of diatom frustules in the samples of cooked non-vegetarian foodstuffs that impend human consumption in Kelantan, Malaysia. It is found that 50 g each of cleaned and cooked prawns and of clams impending human consumption contain about 8360 and 29,054 diatom frustules, respectively. A person accustomed to prawn and clam food would be ingesting an estimated 2 million diatoms in a single year. Considering the suggestion that detection of five diatom frustules in 10 g of bone marrow would suffice for concluding drowning as mode of death, and the fact that there is yet no proof that diatom frustules do not enter into the human systemic circulation through the digestive tract, the estimated number of diatom frustules routinely ingested acquires significance since entry of a few of such ingested frustules into the systemic circulation can lead to false positive test results. The findings of this research raise two important issues: first, population based routine food related diatom ingestion requires to be estimated, and, second, studies have to be initiated to categorically prove or disprove the possibility of entry of diatom frustules into the systemic circulation via the digestive tract.
This study was conducted to determine the proximate composition and energetic value of selected marine fish and shellfish from the West Coast of Peninsular Malaysia. This study has included 20 species of fish (10 pelagic fish and 10 demersal fish) and 4 species of shellfish. For pelagic fish, Longtail shad (terubuk) was found to contain significantly lower moisture (59.31+0.00%), but significantly higher fat content (23.15+0.00%) compared to other fish species. For demersal fish, moisture and ash contents ranged between 74-82%, and 0.9-2.1%, respectively. Long-tailed butterfly ray contained the highest protein (22.22+1.24%) compared to other fish studied. The highest fat content of demersal fish was in Moonfish at 6.89+2.76%. For shellfish, prawn contained the highest protein (19.12+1.44%). The fat content of shellfish ranged between 1-2%. Oyster contained significantly higher carbohydrate at 6.45+0.00%, compared to other shellfish. Longtail shad contained the highest energetic value of 13.34 kJ g-1 of all samples. These values are useful references for consumers in order to choose fish and shellfish based on their nutritional contents.
Infectious hypodermal and haematopoietic necrosis virus (IHHNV) has been detected widely in penaeid culture facilities in Asia and the Americas. IHHNV infection on sub-adult and postlarvae of the giant freshwater prawn, Macrobrachium rosenbergii which had caused up to 80% mortalities was first reported in Southeast Taiwan in 2006. In Malaysia, although, there has been no report on IHHNV infections in M. rosenbergii, preliminary work suggests that there is an urgent need to setup a screening protocol for IHHNV for both wild and cultured populations. In this study, polymerase chain reaction based screening was carried out on 30 randomly sampled berried wild M. rosenbergii before and after spawning. All samples did not showed any sign of IHHNV infection. However, the results showed that 20% of the samples were IHHNV positive. Sequence analysis of the amplified band using NCBI-BLAST showed that the putative IHHNV sequence had 98% nucleotide sequence (388 bp) identity with the IHHNV isolate AC-05-005 non-structural protein 1 gene and seven other IHHNV strains in the data bank further affirming the suggestion on the presence of IHHNV in wild freshwater prawn populations in Malaysia.
The present study describes the length-weight relationships (LWRs) of four Acetes species (Acetes indicus, A. serrulatus,
A. japonicus and A. sibogae) which were sampled from offshore trawling and inshore catches along the west coast of
Peninsular Malaysia. Morphometric measurements (total length, TL and wet weight, WW) were obtained from the samples
and LWRs were estimated. All LWRs were significant (p<0.05) for the four species, with the coefficient of determination, R2
>
0.659. The estimated b values for LWR were 2.432-3.403. The R2
value was >0.84 when the data was analysed according
to inshore and offshore samples. Male and female A. indicus and A. serrulatus demonstrated negative allometric growth
whilst male A. japonicus and A. sibogae showed isometric growth type. Positive allometric growth was depicted by a
combined group of male and female A. sibogae. This study has contributed to the knowledge of the offshore and inshore
distribution patterns of different populations of Acetes spp. in the Straits of Malacca. It also presents a comparison of
the LWRs between offshore and inshore catches of A. indicus and A. serrulatus, with the inshore catches of A. japonicus
and A. sibogae, which have not been previously reported. The findings of this study would contribute to the conservation
and management of this commercially important fisheries resource.
The invasive freshwater crayfish Orconectes limosus mitogenome was recovered by genome skimming. The mitogenome is 16,223 base pairs in length consisting of 13 protein-coding genes, 2 ribosomal subunit genes, 22 transfer RNAs, and a non-coding AT-rich region. The O. limosus mitogenome has an AT bias of 71.37% and base composition of 39.8% for T, 10.3% for C, 31.5% for A, and 18.4% for G. The mitogene order is identical to two other genera of northern hemisphere crayfish that have been sequenced for this organelle.
The mitochondrial genome sequence of the Australian freshwater shrimp, Paratya australiensis, is presented, which is the fourth for genera of the superfamily Atyoidea and the first atyid from the southern hemisphere. The base composition of the P. australiensis, mitogenome is 33.55% for T, 18.24% for C, 35.16% for A, and 13.06% for G, with an AT bias of 71.58%. It has a mitogenome of 15,990 base pairs comprised of 13 protein-coding, 2 ribosomal subunit and 22 transfer RNAs genes and a non-coding AT-rich region. The mitogenome gene order for the species is typical for atyid shrimps, which conform to the primitive pan crustacean model.
The complete mitochondrial genome of the Bass yabby Trypaea australiensis was obtained from a partial genome scan using the MiSeq sequencing system. The T. australiensis mitogenome is 16,821 bp in length (70.25% A + T content) made up of 13 protein-coding genes, 2 ribosomal subunit genes, 22 transfer RNAs and a putative 1977 bp non-coding AT-rich region. This Trypaea mitogenome sequence is the 5th for the family Callianassidae and represents a new gene order for the Decapoda involving protein-coding, rRNA and tRNA genes and the control region.
Next-Gen sequencing was used to recover the complete mitochondrial genome of Cherax tenuimanus. The mitogenome consists of 15,797 base pairs (68.14% A + T content) containing 13 protein-coding genes, two ribosomal subunit genes, 22 transfer RNAs, and a 779 bp non-coding AT-rich region. Mitogenomes have now been recovered for all six species of Cherax native to Western Australia.
The complete mitochondrial genome of the hermit crab Clibanarius infraspinatus was recovered by genome skimming using Next-Gen sequencing. The Clibanarius infraspinatus mitogenome has 16,504 base pairs (67.94% A + T content) made up of 13 protein-coding genes, 2 ribosomal subunit genes, 22 transfer RNAs and a putative 1500 bp non-coding AT-rich region. The Clibanarius infraspinatus mitogenome sequence is the first for the family Diogenidae and the second for the superfamily Paguroidea and exhibits a translocation of the ND3 gene not previously reported for the Decapoda.
The mitochondrial genome sequence of the stone crab, Myomenippe fornasinii, second of the superfamily Eriphioidea is documented. Myomenippe fornasinii has a mitogenome of 15,658 base pairs consisting of 13 protein-coding genes, 2 ribosomal subunit genes, 22 transfer RNAs and a non-coding AT-rich region. The base composition of the M. fornasinii mitogenome is 36.10% for T, 18.52% for C, 35.48% for A, and 9.90% for G, with an AT bias of 71.58%. The mitogenome gene order conforms to what is the standard arrangement for brachyuran crabs.
The mitochondrial genome sequence of the Morton Bay bug, Thenus orientalis, is documented, which makes it the second mitogenome for species of the family Scyllaridae and the ninth for members of the superfamily Palinuroidae. Thenus orientalis has a mitogenome of 16,826 base pairs consisting of 13 protein-coding genes, 2 ribosomal subunit genes, 23 transfer RNAs, and a non-coding AT-rich region. The base composition of the T. orientalis mitogenome is 31.31% for T, 23.77% for C, 31.05% for A, and 13.87% for G, with an AT bias of 62.36%. In addition to a duplicated trnS1 and several other tRNA gene rearrangements, the mitogenome gene order has novel protein coding gene order with the nad6 and cob genes translocated as a block to a location downstream of the nad3 gene.
The complete mitochondrial genome of the swimming crab Thalamita crenata was obtained from a partial genome scan using the MiSeq sequencing system. The Thalamita crenata mitogenome has 15,787 base pairs (70% A+T content) made up of 13 protein-coding genes, 2 ribosomal subunit genes, 22 transfer RNAs, and a putative 897 bp non-coding AT-rich region. This Thalamita mitogenome sequence is the first for the genus and the eighth for the family Portunidae.
The complete mitochondrial genome of the moon crab Ashtoret lunaris was obtained from a partial genome scan using the MiSeq sequencing system. The Ashtoret lunaris mitogenome is 15,807 base pairs in length (70% A + T content) and made up of 13 protein-coding genes, 2 ribosomal subunit genes, 22 transfer RNAs, and a putative 956 bp non-coding AT-rich region. This A. lunaris mitogenome sequence is the first for the genus, as well as the family Matutidae and superfamily Calappoidea.
The intra- and inter-specific variation of Acetes shrimps were evaluated based on samples collected from in-shore catches and off-shore trawling around the west coast of Peninsular Malaysia. Species captured were identified as Acetes indicus, A. serrulatus, A. japonicus and A. sibogae. A region of the mitochondrial cytochrome c oxidase subunit I (COI) gene comprising 552 base pairs (bp) was amplified from 159 Acetes specimens. The sequence alignment analysis generated phylogenetic trees which depicted the four major clades that were consistent with the species identified morphologically. These four species varied considerably for haplotype and nucleotide diversity, with A. indicus and A. serrulatus showing different demographic histories. Furthermore, the observation of two clades in the A. indicus and A. sibogae lineages, with relatively high levels of intraspecific divergence, suggests that cryptic diversity is possibly present in these two taxa. This study has contributed to the knowledge of the distribution patterns and molecular phylogenetics of four Acetes spp. in the Straits of Malacca.
This study presents the first ever data of extracting chitin from the Chiton shell, which was then converted to the soluble chitosan by soaking in the 45% NaOH solution. The obtained chitin and chitosan were characterized by the seven different methods. Antioxidant activity of the extracted chitosan was also evaluated using the two methods. The shell content was divided into calcium carbonate (90.5 %), protein (5.2%), and chitin (4.3 %). Due to the results of element analysis and 1H NMR, the final degree of deacetylation of chitosan was 90%. Surprisingly, a significant amount of Fe was accidentally found in the shell after demineralization, and removed from the solution through the filtering. Nonetheless, remained Fe in the extracted chitin and chitosan was 20 times higher than those previously reported from the shell of shrimps and crabs. Presence of this amount of Fe could describe why the produced chitosan was darker compared to the commercial chitosan. Antioxidant activity tests showed that the IC50 of the extracted chitosan was higher than one estimated for the commercial chitosan. Antioxidant activity of the extracted chitosan is even better than the commercial version and may be used in pharmaceutical industry as a source of antioxidant.
The emergence of cost-effective and rapid sequencing approaches has resulted in an exponential rise in the number of mitogenomes on public databases in recent years, providing greater opportunity for undertaking large-scale comparative genomic and systematic research. Nonetheless, current datasets predominately come from small and disconnected studies on a limited number of related species, introducing sampling biases and impeding research of broad taxonomic relevance. This study contributes 21 crustacean mitogenomes from several under-represented decapod infraorders including Polychelida and Stenopodidea, which are used in combination with 225 mitogenomes available on NCBI to investigate decapod mitogenome diversity and phylogeny. An overview of mitochondrial gene orders (MGOs) reveals a high level of genomic variability within the Decapoda, with a large number of MGOs deviating from the ancestral arthropod ground pattern and unevenly distributed among infraorders. Despite the substantial morphological and ecological variation among decapods, there was limited evidence for correlations between gene rearrangement events and species ecology or lineage specific nucleotide substitution rates. Within a phylogenetic context, predicted scenarios of rearrangements show some MGOs to be informative synapomorphies for some taxonomic groups providing strong independent support for phylogenetic relationships. Additional comparisons for a range of mitogenomic features including nucleotide composition, strand asymmetry, unassigned regions and codon usage indicate several clade-specific trends that are of evolutionary and ecological interest.