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Zhu Z.Y.,Molecular Population Genetics Group | Wang C.M.,Molecular Population Genetics Group | Lo L.C.,Molecular Population Genetics Group | Lin G.,Molecular Population Genetics Group | And 7 more authors.
Animal Genetics | Year: 2010

Summary Microsatellites are the most popular markers for parentage assignment and population genetic studies. To meet the demand for international comparability for genetic studies of Asian seabass, a standard panel of 28 microsatellites has been selected and characterized using the DNA of 24 individuals from Thailand, Malaysia, Indonesia and Australia. The average allele number of these markers was 10.82 ± 0.71 (range: 6-19), and the expected heterozygosity averaged 0.76 ± 0.02 (range: 0.63-1.00). All microsatellites showed Mendelian inheritance. In addition, eight standard size controls have been developed by cloning a set of microsatellite alleles into a pGEM-T vector to calibrate allele sizes determined by different laboratories, and are available upon request. Seven multiplex PCRs, each amplifying 3-5 markers, were optimized to accurately and rapidly genotype microsatellites. Parentage assignment using 10 microsatellites in two crosses (10-10 and 20-20) demonstrated a high power of these markers for revealing parent-sibling connections. This standard set of microsatellites will standardize genetic diversity studies of Asian seabass, and the multiplex PCR sets will facilitate parentage assignment. © 2009 The Authors.


Jiang D.,Agri Food and Veterinary Authority of Singapore | Tikhomirova A.,University of Adelaide | Kidd S.P.,University of Adelaide
Research in Microbiology | Year: 2016

An alcohol dehydrogenase, AdhC, is required for Haemophilus influenzae Rd KW20 growth with high oxygen. AdhC protects against both exogenous and metabolically generated, endogenous reactive aldehydes. However, adhC in the strain 86-028NP is a pseudogene. Unlike the Rd KW20 adhC mutant, 86-028NP does grow with high oxygen. This suggests the differences between Rd KW20 and 86-028NP include broader pathways, such as for the maintenance of redox and metabolism that avoids the toxicity related to oxygen. We hypothesized that these differences affect their resistance to relevant toxic chemicals, including reactive aldehydes. Across a range of oxygen concentrations, despite the growth profiles of Rd KW20 and 86-028NP being similar, there was a significant variation in their sensitivity to reactive aldehydes. 86-028NP is more sensitive to methylglyoxal, formaldehyde and glycolaldehyde under high oxygen than low oxygen as well as compared to Rd KW20. Also, as oxygen levels changed the whole genome gene expression profiles of Rd KW20 and 86-028NP revealed distinctions in their transcriptomes (the iron, FNR and ArcAB regulons). These were indicative of a difference in their intracellular redox properties and we show it is this that underpins their survival against reactive aldehydes. © 2015 Institut Pasteur.


George S.,Center for Sustainable Nanotechnology | Ho S.S.,Nanyang Technological University | Wong E.S.P.,Nanyang Technological University | Tan T.T.Y.,Nanyang Technological University | And 10 more authors.
Nanotoxicology | Year: 2015

An international symposium for nanosafety was held recently at the Nanyang Technological University in Singapore. Topics relating to understanding nanomaterial properties, tools, and infrastructure required for predicting hazardous outcomes, measuring nanomaterial exposure levels, systems approach for risk assessment and public's perception of nanotechnology were covered. The need for a multidisciplinary approach, across both natural and social sciences, for developing sustainable nanotechnology solutions was heavily emphasized. This commentary highlights the major issues discussed and the commitment of the nanosafety research community in Singapore to contribute collectively to realise the vision of sustainable nanotechnology. © 2015 The Author(s). Published by Taylor & Francis.


Yeo D.S.-Y.,Defence Medical and Environmental Research Institute | Lian J.E.,Nanyang Technological University | Fernandez C.J.,Agri Food and Veterinary Authority of Singapore | Lin Y.-N.,Agri Food and Veterinary Authority of Singapore | And 10 more authors.
Virology Journal | Year: 2013

Background: In 2001 and 2002, fatal myocarditis resulted in the sudden deaths of four, two adult and two juvenile, orang utans out of a cohort of 26 in the Singapore Zoological Gardens. Methods. Of the four orang utans that underwent post-mortem examination, virus isolation was performed from the tissue homogenates of the heart and lung obtained from the two juvenile orang utans in Vero cell cultures. The tissue culture fluid was examined using electron microscopy. Reverse transcription and polymerase chain reaction with Encephalomyocarditis virus (EMCV)-specific primers targeting the gene regions of VP3/VP1 and 3D polymerase (3Dpol) confirmed the virus genus and species. The two EMCV isolates were sequenced and phylogenetic analyses of the virus genes performed. Serological testing on other animal species in the Singapore Zoological Gardens was also conducted. Results: Electron microscopy of the two EMCV isolates, designated Sing-M100-02 and Sing-M105-02, revealed spherical viral particles of about 20 to 30 nm, consistent with the size and morphology of members belonging to the family Picornaviridae. In addition, infected-Vero cells showed positive immunoflorescence staining with antiserum to EMCV. Sequencing of the viral genome showed that the two EMCV isolates were 99.9% identical at the nucleotide level, indicating a similar source of origin. When compared with existing EMCV sequences in the VP1 and 3Dpol gene regions, the nucleotide divergence were at a maximum of 38.8% and 23.6% respectively, while the amino acid divergence were at a maximum of 33.9% and 11.3% respectively. Phylogenetic analyses of VP1 and 3Dpol genes further grouped the Sing-M100-02 and Sing-M105-02 isolates to themselves, away from existing EMCV lineages. This strongly suggested that Sing-M100-02 and Sing-M105-02 isolates are highly divergent variants of EMCV. Apart from the two deceased orang utans, a serological survey conducted among other zoo animals showed that a number of other animal species had neutralizing antibodies to Sing-M105-02 isolate, indicating that the EMCV variant has a relatively wide host range. Conclusions: The etiological agent responsible for the fatal myocarditis cases among two of the four orang utans in the Singapore Zoological Gardens was a highly divergent variant of EMCV. This is the first report of an EMCV infection in Singapore and South East Asia. © 2013 Yeo et al.; licensee BioMed Central Ltd.


Wang C.M.,National University of Singapore | Lo L.C.,National University of Singapore | Zhu Z.Y.,National University of Singapore | Pang H.Y.,National University of Singapore | And 6 more authors.
Marine Biotechnology | Year: 2011

The caudal fin represents a fundamental design feature of fishes and plays an important role in locomotor dynamics in fishes. The shape of caudal is an important parameter in traditional systematics. However, little is known about genes involved in the development of different forms of caudal fins. This study was conducted to identify and map quantitative trait loci (QTL) affecting the length of caudal fin and the ratio between tail length and standard body length in Asian seabass (Lates calcarifer). One F1 family containing 380 offspring was generated by crossing two unrelated individuals. One hundred and seventeen microsatellites almost evenly distributed along the whole genome were genotyped. Length of caudal fin at 90 days post-hatch was measured. QTL analysis detected six significant (genome-wide significant) and two suggestive (linkage-group-wide significant) QTL on seven linkage groups. The six significant QTL explained 5.5-16.6% of the phenotypic variance, suggesting these traits were controlled by multiple genes. Comparative genomics analysis identified several potential candidate genes for the length of caudal fin. The QTL for the length of caudal fin detected for the first time in marine fish may provide a starting point for the future identification of genes involved in the development of different forms of caudal fins in fishes. © 2010 Springer Science+Business Media, LLC.

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