Displaying publications 81 - 100 of 267 in total

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  1. Jamsari AF, Min-Pau T, Siti-Azizah MN
    Genet Mol Biol, 2011 Apr;34(2):345-7.
    PMID: 21734840
    Seven polymorphic microsatellite loci were isolated and characterized for the snakehead murrel, Channa striata (Channidae), a valuable tropical freshwater fish species. Among 25 specimens collected from Kedah state in Malaysia, the number of alleles per locus ranged from 2 to 7. Observed and expected heterozygosities ranged from 0.120 to 0.880 and 0.117 to 0.698, respectively. A single locus (CS1-C07) was significantly deviated from Hardy-Weinberg equilibrium after Bonferroni correction. These novel markers would be useful for population genetic studies of the C. striata.
    Matched MeSH terms: Fresh Water
  2. Tan WS, Yin WF, Chang CY, Chan KG
    Genome Announc, 2015;3(1).
    PMID: 25700404 DOI: 10.1128/genomeA.01548-14
    Aeromonas hydrophila is a well-known waterborne pathogen that recently was found to infect humans. Here, we report the draft genome of a freshwater isolate from a Malaysian waterfall, A. hydrophila strain M023, which portrays N-acylhomoserine lactone-dependent quorum sensing.
    Matched MeSH terms: Fresh Water
  3. Chan KG, Tan WS, Chang CY, Yin WF, Mumahad Yunos NY
    Genome Announc, 2015;3(2).
    PMID: 25767237 DOI: 10.1128/genomeA.00100-15
    Aeromonas hydrophila has emerged worldwide as a human pathogen. Here, we report the draft whole-genome sequence of a freshwater isolate from Malaysia, A. hydrophila strain M062, and its N-acylhomoserine lactone genes are also reported here.
    Matched MeSH terms: Fresh Water
  4. Chan KG, Tan WS
    Genome Announc, 2015;3(1).
    PMID: 25676763 DOI: 10.1128/genomeA.01554-14
    Pectobacterium carotovorum is known to cause serious damage to various major crops worldwide. Here, we report the draft genome of Pectobacterium carotovorum strain M022, a freshwater isolate from a Malaysian waterfall, which has been reported as a plant pathogen and is able to communicate with N-acylhomoserine lactone-mediated quorum sensing.
    Matched MeSH terms: Fresh Water
  5. Chan KG, Yunos NY
    Genome Announc, 2016;4(2).
    PMID: 26941152 DOI: 10.1128/genomeA.00081-16
    Here, we report the draft genome sequence of Chromobacterium piscinae strain ND17. This bacterium was isolated from a fresh water sample in Malaysia and exhibits quorum-sensing activity. This first draft genome of C. piscinae strain ND17 will pave the way to future studies of the quorum-sensing properties of this isolate.
    Matched MeSH terms: Fresh Water
  6. Knox SH, Bansal S, McNicol G, Schafer K, Sturtevant C, Ueyama M, et al.
    Glob Chang Biol, 2021 08;27(15):3582-3604.
    PMID: 33914985 DOI: 10.1111/gcb.15661
    While wetlands are the largest natural source of methane (CH4 ) to the atmosphere, they represent a large source of uncertainty in the global CH4 budget due to the complex biogeochemical controls on CH4 dynamics. Here we present, to our knowledge, the first multi-site synthesis of how predictors of CH4 fluxes (FCH4) in freshwater wetlands vary across wetland types at diel, multiday (synoptic), and seasonal time scales. We used several statistical approaches (correlation analysis, generalized additive modeling, mutual information, and random forests) in a wavelet-based multi-resolution framework to assess the importance of environmental predictors, nonlinearities and lags on FCH4 across 23 eddy covariance sites. Seasonally, soil and air temperature were dominant predictors of FCH4 at sites with smaller seasonal variation in water table depth (WTD). In contrast, WTD was the dominant predictor for wetlands with smaller variations in temperature (e.g., seasonal tropical/subtropical wetlands). Changes in seasonal FCH4 lagged fluctuations in WTD by ~17 ± 11 days, and lagged air and soil temperature by median values of 8 ± 16 and 5 ± 15 days, respectively. Temperature and WTD were also dominant predictors at the multiday scale. Atmospheric pressure (PA) was another important multiday scale predictor for peat-dominated sites, with drops in PA coinciding with synchronous releases of CH4 . At the diel scale, synchronous relationships with latent heat flux and vapor pressure deficit suggest that physical processes controlling evaporation and boundary layer mixing exert similar controls on CH4 volatilization, and suggest the influence of pressurized ventilation in aerenchymatous vegetation. In addition, 1- to 4-h lagged relationships with ecosystem photosynthesis indicate recent carbon substrates, such as root exudates, may also control FCH4. By addressing issues of scale, asynchrony, and nonlinearity, this work improves understanding of the predictors and timing of wetland FCH4 that can inform future studies and models, and help constrain wetland CH4 emissions.
    Matched MeSH terms: Fresh Water
  7. Tiruvayipati S, Bhassu S
    Gut Pathog, 2016;8:15.
    PMID: 27114742 DOI: 10.1186/s13099-016-0097-1
    Macrobrachium rosenbergii is well-known as the giant freshwater prawn, and is a commercially significant source of seafood. Its production can be affected by various bacterial contaminations. Among which, the genus Vibrio shows a higher prevalence in aquatic organisms, especially M. rosenbergii, causing food-borne illnesses. Vibrio parahaemolyticus, a species of Vibrio is reported as the main causative of the early mortality syndrome. Vibrio parahaemolyticus infection in M. rosenbergii was studied previously in relation to the prawn's differentially expressed immune genes. In the current review, we will discuss the growth conditions for both V. parahaemolyticus and M. rosenbergii and highlight the role of magnesium in common, which need to be fully understood. Till date, there has not been much research on this aspect of magnesium. We postulate a model that screens a magnesium-dependent pathway which probably might take effect in connection with N-acetylglucosamine binding protein and chitin from V. parahaemolyticus and M. rosenbergii, respectively. Further studies on magnesium as an environment for V. parahaemolyticus and M. rosenbergii interaction studies will provide seafood industry with completely new strategies to employ and to avoid seafood related contaminations.
    Matched MeSH terms: Fresh Water
  8. Rao R, Bing Zhu Y, Alinejad T, Tiruvayipati S, Lin Thong K, Wang J, et al.
    Gut Pathog, 2015;7:6.
    PMID: 25922623 DOI: 10.1186/s13099-015-0052-6
    The Malaysian giant freshwater prawn, Macrobrachium rosenbergii, is an economically important crustacean worldwide. However, production of this prawn is facing a serious threat from Vibriosis disease caused by Vibrio species such as Vibrio parahaemolyticus. Unfortunately, the mechanisms involved in the immune response of this species to bacterial infection are not fully understood. We therefore used a high-throughput deep sequencing technology to investigate the transcriptome and comparative expression profiles of the hepatopancreas from this freshwater prawn infected with V. parahaemolyticus to gain an increased understanding of the molecular mechanisms underlying the species' immune response to this pathogenic bacteria.
    Matched MeSH terms: Fresh Water
  9. Noor AF, Soo TCC, Ghani FM, Goh ZH, Khoo LT, Bhassu S
    Heliyon, 2017 Dec;3(12):e00446.
    PMID: 29322096 DOI: 10.1016/j.heliyon.2017.e00446
    Background: Dystrophin, an essential protein functional in the maintenance of muscle structural integrity is known to be responsible for muscle deterioration during white spot syndrome virus (WSSV) infection among prawn species. Previous studies have shown the upregulation of dystrophin protein in Macrobrachium rosenbergii (the giant freshwater prawn) upon white spot syndrome virus (WSSV) infection. The literature has also suggested the important role of calcium ion alterations in causing such muscle diseases. Thus, the interest of this study lies within the linkage between dystrophin functioning, intracellular calcium and white spot syndrome virus (WSSV) infection condition.

    Methods: In this study, the dystrophin gene from M. rosenbergii (MrDys) was first characterised followed by the characterization of dystrophin gene from a closely related shrimp species, Penaeus monodon (PmDys). Dystrophin sequences from different phyla were then used for evolutionary comparison through BLAST analysis, conserved domain analysis and phylogenetic analysis. The changes in mRNA expression levels of dystrophin and the alteration of intracellular calcium concentrations in WSSV infected muscle cells were then studied.

    Results: A 1246 base pair long dystrophin sequence was identified in the giant freshwater prawn, Macrobrachium rosenbergii (MrDys) followed by 1082 base pair long dystrophin sequence in P. monodon (PmDys). Four conserved domains were identified from the thirteen dystrophin sequences compared which were classified into 5 different phyla. From the phylogenetic analysis, aside from PmDys, the characterised MrDys was shown to be most similar to the invertebrate phylum of Nematoda. In addition, an initial down-regulation of dystrophin gene expression followed by eventual up-regulation, together with an increase in intracellular calcium concentration [Ca2+]
    i
    were shown upon WSSV experimental infection.

    Discussion: Both the functionality of the dystrophin protein and the intracellular calcium concentration were affected by WSSV infection which resulted in progressive muscle degeneration. An increased understanding of the role of dystrophin-calcium in MrDys and the interactions between these two components is necessary to prevent or reduce occurrences of muscle degeneration caused by WSSV infection, thereby reducing economic losses in the prawn farming industry from such disease.

    Matched MeSH terms: Fresh Water
  10. Harrisson K, Pavlova A, Gan HM, Lee YP, Austin CM, Sunnucks P
    Heredity (Edinb), 2016 Jun;116(6):506-15.
    PMID: 26883183 DOI: 10.1038/hdy.2016.8
    Climatic differences across a taxon's range may be associated with specific bioenergetic demands and may result in genetics-based metabolic adaptation, particularly in aquatic ectothermic organisms that rely on heat exchange with the environment to regulate key physiological processes. Extending down the east coast of Australia, the Great Dividing Range (GDR) has a strong influence on climate and the evolutionary history of freshwater fish species. Despite the GDR acting as a strong contemporary barrier to fish movement, many species, and species with shared ancestries, are found on both sides of the GDR, indicative of historical dispersal events. We sequenced complete mitogenomes from the four extant species of the freshwater cod genus Maccullochella, two of which occur on the semi-arid, inland side of the GDR, and two on the mesic coastal side. We constructed a dated phylogeny and explored the relative influences of purifying and positive selection in the evolution of mitogenome divergence among species. Results supported mid- to late-Pleistocene divergence of Maccullochella across the GDR (220-710 thousand years ago), bringing forward previously reported dates. Against a background of pervasive purifying selection, we detected potentially functionally relevant fixed amino acid differences across the GDR. Although many amino acid differences between inland and coastal species may have become fixed under relaxed purifying selection in coastal environments rather than positive selection, there was evidence of episodic positive selection acting on specific codons in the Mary River coastal lineage, which has consistently experienced the warmest and least extreme climate in the genus.
    Matched MeSH terms: Fresh Water
  11. Pavlova A, Gan HM, Lee YP, Austin CM, Gilligan DM, Lintermans M, et al.
    Heredity (Edinb), 2017 05;118(5):466-476.
    PMID: 28051058 DOI: 10.1038/hdy.2016.120
    Genetic variation in mitochondrial genes could underlie metabolic adaptations because mitochondrially encoded proteins are directly involved in a pathway supplying energy to metabolism. Macquarie perch from river basins exposed to different climates differ in size and growth rate, suggesting potential presence of adaptive metabolic differences. We used complete mitochondrial genome sequences to build a phylogeny, estimate lineage divergence times and identify signatures of purifying and positive selection acting on mitochondrial genes for 25 Macquarie perch from three basins: Murray-Darling Basin (MDB), Hawkesbury-Nepean Basin (HNB) and Shoalhaven Basin (SB). Phylogenetic analysis resolved basin-level clades, supporting incipient speciation previously inferred from differentiation in allozymes, microsatellites and mitochondrial control region. The estimated time of lineage divergence suggested an early- to mid-Pleistocene split between SB and the common ancestor of HNB+MDB, followed by mid-to-late Pleistocene splitting between HNB and MDB. These divergence estimates are more recent than previous ones. Our analyses suggested that evolutionary drivers differed between inland MDB and coastal HNB. In the cooler and more climatically variable MDB, mitogenomes evolved under strong purifying selection, whereas in the warmer and more climatically stable HNB, purifying selection was relaxed. Evidence for relaxed selection in the HNB includes elevated transfer RNA and 16S ribosomal RNA polymorphism, presence of potentially mildly deleterious mutations and a codon (ATP6113) displaying signatures of positive selection (ratio of nonsynonymous to synonymous substitution rates (dN/dS) >1, radical change of an amino-acid property and phylogenetic conservation across the Percichthyidae). In addition, the difference could be because of stronger genetic drift in the smaller and historically more subdivided HNB with low per-population effective population sizes.
    Matched MeSH terms: Fresh Water
  12. Froufe E, Bolotov I, Aldridge DC, Bogan AE, Breton S, Gan HM, et al.
    Heredity (Edinb), 2020 Jan;124(1):182-196.
    PMID: 31201385 DOI: 10.1038/s41437-019-0242-y
    Using a new fossil-calibrated mitogenome-based approach, we identified macroevolutionary shifts in mitochondrial gene order among the freshwater mussels (Unionoidea). We show that the early Mesozoic divergence of the two Unionoidea clades, Margaritiferidae and Unionidae, was accompanied by a synchronous split in the gene arrangement in the female mitogenome (i.e., gene orders MF1 and UF1). Our results suggest that this macroevolutionary jump was completed within a relatively short time interval (95% HPD 201-226 Ma) that coincided with the Triassic-Jurassic mass extinction. Both gene orders have persisted within these clades for ~200 Ma. The monophyly of the so-called "problematic" Gonideinae taxa was supported by all the inferred phylogenies in this study using, for the first time, the M- and F-type mitogenomes either singly or combined. Within Gonideinae, two additional splits in the gene order (UF1 to UF2, UF2 to UF3) occurred in the Mesozoic and have persisted for ~150 and ~100 Ma, respectively. Finally, the mitogenomic results suggest ancient connections between freshwater basins of East Asia and Europe near the Cretaceous-Paleogene boundary, probably via a continuous paleo-river system or along the Tethys coastal line, which are well supported by at least three independent but almost synchronous divergence events.
    Matched MeSH terms: Fresh Water
  13. Yee W, Kumar JN, Muthusamy PD
    Indian J Microbiol, 2018 Mar;58(1):109-113.
    PMID: 29434405 DOI: 10.1007/s12088-017-0698-5
    2-mercaptoethanol (2-ME), alongside polyvinylpyrrolidone is commonly used in plant DNA extractions to deal with polyphenols, which could interfere with extraction and downstream applications. 2-ME is also commonly used to denature proteins and nucleases, especially RNAses. On the contrary, we found that the presence of 2-ME in lysis buffer interfered with DNA extraction from 12 strains of freshwater microalgae, resulting in DNA with poor integrity. We also found that the TNES-urea buffer, commonly used for preservation and DNA extraction from fish, appears as effective as the SDS and CTAB buffer for some microalgae strains. Results from our study suggests that the inclusion of 2-ME in DNA extraction protocols may be detrimental for isolation of good quality DNA from freshwater microalgae, and therefore recommend eliminating it or testing varying concentrations of 2-ME when developing species-specific extraction protocols for microalgae.
    Matched MeSH terms: Fresh Water
  14. Asmah, R., Siti Sumaiyah, S.A., Nurul, S.R.
    MyJurnal
    Omega-3 fatty acids have been shown to reduce the risk of chronic diseases like cardiovascular disease and cancer as well as promote brain development among infants and children. This study was carried out to compare total protein, fat and omega-3 fatty acids content of raw and pressurized fish of P. pangasius (yellowtail catfish) and H. macrura (long tail shad). The fish was cooked using pressure cooker for six minute to be pressurized. The protein content was determined by using Kjedahl method while total fat was determined using solvent extraction using chloroform and methanol. Fatty acid methyl esters (FAME) were prepared by a direct transesterification method, and quantified by gas chromatography using external standard. Results showed that marine fish H. macrura (long tail shad) had higher content (p < 0.05) of protein (18.30 ± 0.040 g/100 g), fat (10.965 ± 1.610 g/100 g), EPA (11.83 ± 0.02 g/100 g) and DHA (5.96 ± 0.31 g/100 g) compared to freshwater fish P. pangasius (yellowtail catfish). The protein content of pressurized fish was higher compare to raw fish, but there was no difference in total fat and omega-3 fatty acids content between raw and pressurized of freshwater fish P. pangasius and marine fish, H. macrura. In conclusion, marine fish are better source of protein, fat and omega-3 content, while pressurized fish shown to have comparable amount of protein, fat and omega-3 fatty acids content with raw fish. The result obtained assist the consumers to prepare a healthy menu in order to retain the protein and omega-3 fatty acids content of fish through healthy way of cooking.
    Matched MeSH terms: Fresh Water
  15. MyJurnal
    A total of 49 isolates of V. parahaemolyticus and 8 isolates of V. cholerae isolated from freshwater fish of patin (Pangasius hypopthalmus) and red tilapia (Oreochromis sp.) were purchased from different retail level in Selangor, Malaysia. All of the isolates showed a multiple resistances towards all 15 antibiotics tested. Some of the isolates show a high resistance to different antibiotics including bacitracin, vancomycin, tetracycline, furazididone, cephalothin and erythromycin. However, both species was susceptible towards imipenem. Overall antibiotics resistance patterns of all isolates were resistant from 2 to 14 resistance patterns with multiple antibiotic resistance (MAR) index ranging from 0.13 to 0.93 respectively. As the results obtained in the dendrogram produced from both species had indicates that these antibiotics were intensively used whether in the aquaculture farm through feeds during culture or at the hatchery production of seed. Thus, this study will provides an essential information of the MAR index and also the clustering analysis in order to determine the biosafety of Vibrio spp. in freshwater aquaculture fish sold at different retail level in Malaysia.
    Matched MeSH terms: Fresh Water
  16. Wan Rosli W. I., Rohana, A. J., Gan, S. H., Noor Fadzlina, H., Rosliza, H., Helmy, H., et al.
    MyJurnal
    The total lipid contents and the concentration of eicosapentaenoic (EPA) and docosahexaenoic
    (DHA) fatty acid of fourteen selected marine, three freshwater fish species, four shellfish species and two selected canned fish species of East Coast of Peninsular Malaysia were determined. The fat content of all samples ranged from 1.01 % to 15.83 % with silver catfish reported to have the highest value. Most of the fish had fat amounts lower than 10% of their total weight. In general, DHA concentrations (50.50-165.21 µg/g) were significantly higher than EPA (11.12-55.38 µg/g) in all of the fish species analyzed. Among all marine fish species, the sixbar grouper recorded the highest concentration of DHA (165.21 µg/g) while barramundi had the highest concentration of EPA (55.38 µg/g). In conclusion, all fish and shellfish species are considered a good source of EPA and DHA, representing a very valuable essential nutrient for maintenance of human health.
    Matched MeSH terms: Fresh Water
  17. Abu Bakar, F.
    MyJurnal
    Microbiological quality analysis of freshwater prawns from three sampling sites in Peninsular Malaysia viz: Site 1- Kg. Jumbang, Negri Sembilan; Site 2- Kg. Cangkat Tin, Perak and Site 3- Kg. Cenderiang, Perak for total mesophilic and psychrophilic aerobic counts, proteolytic bacterial counts, histamine producing bacteria, cadaverine producing bacteria and putrescine producing bacteria in the prawns and pond water for the three sites showed that the microbiological quality of freshwater prawns is related to the microflora of pond water in which they were grown. The initial bacterial counts indicated the values were in the range of log 4+ CFU/g for all samples. Total mesophilic and psychrophilic counts of the head regions were higher than that of the body regions for all prawn samples and types of growth media tested. All samples showed an increase in counts with time and temperature of storage up to log 7+ CFU/g for mesophilic counts after 12 hours at ambient, 6 days at 10 ± 2°C and 12 days at iced storage. The samples from Site 2 had relatively higher counts compared to the other two sites which correlated well with the levels determined in the pond water. Similar trends were observed for psychrophilic counts but at lower values for the different types of media studied.
    Effects of preservatives on quality changes and shelf life of shrimp during iced storage indicated that boric acid, lactic acid and sodium metabisulphite managed to inhibit psychrophilic bacteria and biogenic amines formation in prawns while maintaining the mesophilic counts at lower levels during iced storage.
    Matched MeSH terms: Fresh Water
  18. Sara, R.R., Ismail, M.M., Kamarulzaman, N.H., Mohamed, Z.A.
    MyJurnal
    Aquaculture businesses in Malaysia require careful and comprehensive financial analysis to be successful. Comprehensive financial analysis has three key components, namely financial position, profitability and liquidity/cash flow. This research focuses on using pro forma income statements to analyze financial positions and to evaluate the effect of government incentives on sustainability of Malaysian aquaculture farms. This paper is divided into two sections; the first section discusses and provides the finding and comparability of the financial analysis on freshwater and brackish water producers. In the first section, the discussion was based on financial viability criteria, namely net present value (NPV), internal rate of return (IRR) and benefit cost ratio (BCR)) for base study. The evaluation process was carried out using four different phases; base study and government incentives simulations, Pioneer Status (PS), Investment Tax Allowance (ITA), and Accelerated Capital Allowance (ACA) for effectiveness of government incentives and roles in increase of profitability and production. The results showed that in all brackish water farms, NPV after the ACA incentive showed a higher and positive value comparable to individual PS and ITA. The effect of Government Incentive on Penaeus vannamei and Grouper showed that IRR and NPV on ACA (based on PS) is 2% and 9%, respectively higher than ACA (based on ITA). Meanwhile, in Barramundi farming ACA (based on ITA) was 8% higher than ACA (based on PS). The results on freshwater showed that ACA (based on ITA) on Tilapia and Catfish was 8% and 6% higher than ACA (based on PS). This paper concludes that the aquaculture operators should choose to accept PS with ACA on Penaeus vannamei and Grouper and choose ACA based on ITA on Barramundi, Tilapia and Catfish in order to maximize private profitability.
    Matched MeSH terms: Fresh Water
  19. Ng, K.H., Samuel, L., Kathleen, M.M., Leong, S.S., Felecia, C.
    MyJurnal
    In Malaysia, the aquaculture industry, particularly the production of freshwater aquaculture fish, is growing rapidly. Nevertheless, the illegal use of banned antimicrobial agents such as chloramphenicol in aquaculture has become a major concern in relation to the safety of consumers and also the development of drug-resistant strains in bacteria. Driven by those factors, the main intention of this study was to determine the prevalence and types of chloramphenicol resistance genes in E. coli isolated from aquaculture and other environmental waters. The respective chloramphenicol-resistance genes in the isolates were detected by multiplex PCR with four sense primers C-1, C-2, C-3, C-4 and one antisense primer C-R for targeting cat I, cat II, cat III and cat IV genes, respectively. Out of 27 E. coli isolated, 19 were resistant to chloramphenicol. Cat I, cat II, cat III and cat IV genes were detected in 19, 13, 10, and 6 of the E. coli isolates, respectively. The results of this study revealed that chloramphenicol-resistance E. coli is present in aquaculture and environmental waters, in the study area. This finding suggested that although banned, there could be illegal usage of chloramphenicol antibiotic in local aquaculture. The bacteria in aquaculture may have spread to other environmental water through disposal of aquaculture waste water to other environments.
    Matched MeSH terms: Fresh Water
  20. Khai, N. X., Kusairi, M. N., Ahmad, S., Syahaneem, M. Z., Fatimah, M. A.
    MyJurnal
    There are some signals that Malaysian marine landings are decreasing and that wild stocks have been over-fished. However, it has extensive inland water bodies which have the potentials to be developed into freshwater aquaculture sites. Tengas (Neolissochilus sp.), a freshwater type of fish, are found in abundance in Malaysia; but has not reached the commercial level in the market. This paper examines the potential of developing tengas as a commercial freshwater species. The data used in this study were obtained through primary data search from key informants and a survey. A semi-structured open-ended questionnaire with Malay and Chinese languages was designed for the interviews. The study areas covered Peninsular Malaysia and East Malaysia. From the survey, we found that tengas has potential to be taken as a food item and an ornamental fish. The wild stock of tengas in fact is also worthwhile to be conserved for agro-tourism development. Many restaurant operators are willing to invent cooking method on tengas.
    Matched MeSH terms: Fresh Water
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