Displaying publications 21 - 40 of 509 in total

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  1. Priya K, Sulaiman J, How KY, Yin WF, Chan KG
    Arch Microbiol, 2018 Sep;200(7):1135-1142.
    PMID: 29796703 DOI: 10.1007/s00203-018-1526-y
    Quorum sensing (QS) is a term used to describe cell-to-cell communication that enables bacteria to orchestrate group behaviours according to density of bacterial cells. In Gram-negative bacteria, this signalling system is widely known to regulate a variety of different phenotypes such as antibiotic production and biofilm formation. In this study, we report the production of N-acyl homoserine lactones produced by Chromobacterium haemolyticum strain KM2, a bacterium isolated from a river water of a reserved tropical national park. Preliminary screening of QS activity using biosensor reporter assays indicated that C. haemolyticum strain KM2 produces both short- and long-chain AHLs. Analysis with high-resolution liquid chromatography-mass spectrometry (LC-MS/MS) analysis revealed the production of three AHLs by strain KM2: N-octanoyl-L-homoserine lactone (C8-HSL), N-dodecanoyl-L-homoserine lactone (C12-HSL), and N-3-oxo-dodecanoyl-L-homoserine lactone (OC12-HSL). This bacterial isolate also exhibited strong β-haemolytic activity. To the best of our knowledge, this is the first documentation of QS activity and multiple AHLs production by C. haemolyticum strain KM2.
    Matched MeSH terms: Rivers/microbiology*
  2. Osman A, Khalida M, Azman AB, Jamil R, Tan TT, Wu LL, et al.
    Asia Pac J Clin Nutr, 1993 Sep;2(3):115-8.
    PMID: 24352141
    The prevalence of goitre was determined in several communities in rural parts of Pahang. Urine specimens were collected randomly among the participants. Drinking water from various sources such as river and spring, and water from gravity feed systems was also collected to determine the iodine content by using the ashing method. The results were compared to that of Kuala Lumpur City. lt was found that the prevalence of goitre in rural areas was between 20 and 70% depending on village, ethnic group, age and gender. The interior parts of the jungle where Aborigines lived was moderately endemic with goitre prevalence of goitre more than 20% and urinary iodine content 2.0-5.0 μg I/dl). A nearby Malay traditional village which was studied had mild endemia (prevalence 10-30% and urinary iodine content 5.0-10.0 μg I/dl) while a Felda Malay resettlement scheme and Kuala Lumpur City did not have endemic goitre. Endemic goitre in rural areas was associated with low iodine content in drinking water. Even though Kuala Lumpur had low iodine content in its drinking water there was no endemic goitre, indicating that other factors were more important.
    Matched MeSH terms: Rivers
  3. Tan BL, Mustafa AM
    Asia Pac J Public Health, 2004;16(1):54-63.
    PMID: 18839869
    Alkylphenols and most pesticides, especially organochlorine pesticides are endocrine-disrupting chemicals and they usually mimic the female hormone, estrogen. Using these chemicals in our environment would eventually lead us to consume them somehow in the food web. Several rivers in the State of Selangor, Malaysia were selected to monitor the level of alkylphenols and pesticides contamination for several months. The compounds were extracted from the water samples using liquid-liquid extraction method with dichloromethane and ethyl acetate as the extracting solvents. The alkylphenols and pesticides were analyzed by selected ion monitoring (SIM) mode using the quadrapole detector in Shimadzu QP-5000 gas chromatograph-mass spectrometer (GCMS). Recovery of most alkylphenols and pesticides were in the range of 50% to 120%. Trace amounts of the compounds were detected in the river water samples, mainly in the range of parts per trillion. This technique of monitoring the levels of endocrine-disruptors in river water is consistent and cost effective.
    Matched MeSH terms: Rivers/chemistry*
  4. Brunke J, Russo IM, Orozco-terWengel P, Zimmermann E, Bruford MW, Goossens B, et al.
    BMC Genet, 2020 04 17;21(1):43.
    PMID: 32303177 DOI: 10.1186/s12863-020-00849-z
    BACKGROUND: Constraints in migratory capabilities, such as the disruption of gene flow and genetic connectivity caused by habitat fragmentation, are known to affect genetic diversity and the long-term persistence of populations. Although negative population trends due to ongoing forest loss are widespread, the consequence of habitat fragmentation on genetic diversity, gene flow and genetic structure has rarely been investigated in Bornean small mammals. To fill this gap in knowledge, we used nuclear and mitochondrial DNA markers to assess genetic diversity, gene flow and the genetic structure in the Bornean tree shrew, Tupaia longipes, that inhabits forest fragments of the Lower Kinabatangan Wildlife Sanctuary, Sabah. Furthermore, we used these markers to assess dispersal regimes in male and female T. longipes.

    RESULTS: In addition to the Kinabatangan River, a known barrier for dispersal in tree shrews, the heterogeneous landscape along the riverbanks affected the genetic structure in this species. Specifically, while in larger connected forest fragments along the northern riverbank genetic connectivity was relatively undisturbed, patterns of genetic differentiation and the distribution of mitochondrial haplotypes in a local scale indicated reduced migration on the strongly fragmented southern riverside. Especially, oil palm plantations seem to negatively affect dispersal in T. longipes. Clear sex-biased dispersal was not detected based on relatedness, assignment tests, and haplotype diversity.

    CONCLUSION: This study revealed the importance of landscape connectivity to maintain migration and gene flow between fragmented populations, and to ensure the long-term persistence of species in anthropogenically disturbed landscapes.

    Matched MeSH terms: Rivers
  5. Dee KH, Abdullah F, Md Nasir SNA, Appalasamy S, Mohd Ghazi R, Eh Rak A
    Biomed Res Int, 2019;2019:9596810.
    PMID: 31663001 DOI: 10.1155/2019/9596810
    Corbicula fluminea serves as traditional food to the local people in Kelantan, Malaysia. Concerns regarding river contamination, smoking method, and associated adverse effects on public health had been increasing. Hence, this study aims to measure the level of heavy metals (Cd, Cu, Mn, Pb, and Zn) and assess human health risk in C. fluminea consumption at Kelantan. Heavy-metal analysis was done using flame atomic absorption spectrophotometry, while human health risk was assessed using provisional tolerable weekly intake (PTWI), target hazard quotient (THQ), and hazard index (HI). The estimated weekly intake (EWI) for all metals was found within PTWI, while THQ for Cd, Cu, Mn, Pb, and Zn was 0.12, 0.06, 0.04, 0.41, and 0.03, respectively. The HI was calculated at 0.61 which is less than 1, considered as the safe consumption level. Therefore, C. fluminea consumption in this study was found safe from the health risk of noncarcinogenic effect over a lifetime.
    Matched MeSH terms: Rivers/chemistry
  6. Chiu YW, Gan YC, Kuo PH, Hsu KC, Tan MS, Ju YM, et al.
    Biochem Genet, 2018 Oct 26.
    PMID: 30367289 DOI: 10.1007/s10528-018-9892-3
    According to geological history, Peninsular Malaysia and Borneo formed at different times and were once connected during Quaternary glaciations. To determine how this history has influenced phylogeography, our study examined the population genetic structure of the tropical freshwater gastropod Melanoides tuberculata across Peninsular Malaysia and Borneo using the sequences from mitochondrial DNA 16S rRNA and cytochrome oxidase subunit I genes (1168 bp). In total, 104 specimens were collected from seventeen populations. All mtDNA haplotypes were identified as belonging to two highly divergent lineages, and these lineages were almost allopatric in their distributions. Our study found that the freshwater fauna in Malaysia might be divided into four regions: northeast Peninsular Malaysia, northwest Peninsular Malaysia, south Peninsular Malaysia, and Borneo. The phylogeography of M. tuberculata in Malaysia was shaped by the landforms of Peninsular Malaysia and by the paleo-river systems in the Sunda continental shelf. In addition, our study found that these two lineages in Malaysia have invaded the globe. These results suggest that Malaysia is located in important shipping lanes throughout the world, and the populations of M. tuberculate might be widely distributed throughout the world by shipping.
    Matched MeSH terms: Rivers
  7. Abdullah NA, Radzi SNF, Asri LN, Idris NS, Husin S, Sulaiman A, et al.
    Biodivers Data J, 2019;7:e35679.
    PMID: 31582889 DOI: 10.3897/BDJ.7.e35679
    Riparian areas hold vast number of flora and fauna with exceptional contributions to the ecosystem. A study was conducted in Sungai Sepetang, Sungai Rembau and Sungai Chukai to identify the insect community in a riparian zone of Peninsular Malaysia. Sampling was conducted in six consecutive months from December 2017 to May 2018 during both day and night using sweep nets. Twenty sampling stations (S1-S20) had been assembled along the riverbanks with an average distance of 200 m between each station. The 17,530 collected insects were from 11 orders and consisted of Diptera, Coleoptera, Hemiptera, Hymenoptera, Lepidoptera, Neuroptera, Orthoptera, Blattodea, Thysanoptera, Mantodea and Odonata. The three most abundant orders were Diptera (33.84%; 5933 individuals), Coleoptera (28.82%; 5053 individuals) and Hemiptera (25.62%: 4491 individuals). The collected insect community consisted of different guilds such as the scavenger, predator, herbivore, pollinator and parasitoid. Sungai Sepetang and Sungai Rembau were dominated by mangrove flora, Sonneratia caseolaris (Myrtales: Lythraceae), while Sungai Chukai was dominated by Barringtonia racemosa. There was a significant difference (p < 0.05) in the composition of insects between the three rivers though clustering analysis showed that the insect communities in Sungai Sepetang and Sungai Rembau were 100% similar compared to Sungai Chukai which consisted of a totally different community. There is a significant negative correlation between abundance of insects with salinity and wind speed at Sungai Chukai and Sungai Sepetang.
    Matched MeSH terms: Rivers
  8. Nor Fadhillah Mohmaed Azmin, N Shofia A’yun Syafie, Azlin Suhaida Azmi, Mimi Fina Hamidon, Ani Liza Asnawi
    MyJurnal
    Sg. Papar is one of the rivers in Kota Kinabalu which is mainly used for water supply especially in Papar district. For the past years, many pollution cases concerning Sg. Papar have been reported which originated from various sources including pig farm, agricultural run-off and deforestation. These resulted in a frequent shutdown of the water treatment plants in Papar district leading to water supply disturbance and water supply deficiency in the affected area. The data utilized in this study were obtained from water quality tests performed on river water samples taken from Limbahau water treatment plant recorded from September 2013 to September 2016. Principal Component Analysis (PCA) was used in this study to analyze and correlate the physicochemical parameters with the water treatment plant shutdown. The results revealed that eight parameters (pH, alum, nitrate, TDS, DO, conductivity, colour and chloride) analysed in this study correlate with each other and the parameter that mostly caused the drastic change in the river water and as pollution index is turbidity. This study is critical for understanding the relationship between the water quality paramters and environmental issues.
    Matched MeSH terms: Rivers
  9. Nik Nur Syafika Pahri, Nur Huda Syazwani Jafri, Husna Ahmad Tajuddin, Yusilawati Ahmad Nor
    MyJurnal
    Effective treatment of wastewater is crucial in order to achieve a sustainable development. For instance, highly efficient treatment processes with low capital requirements are the major prerequisite for implementation of the advanced wastewater treatment operations. Among various available treatment methods, the application of coagulation-flocculation process by using natural coagulant; chitosan has vast advantages such as low operating cost, environmental friendly and highly effective in the wastewater treatment operations. The application of nanotechnology in numerous treatment techniques are considered as the most significant advances in water and wastewater treatment practices. The utilization of magnesium oxide (MgO) as nano-adsorbent has recently gained attention as a potential treatment method in water remediation particularly for treating effluents with high amount of organic dyes and heavy metals due to its high treatment efficiency, low cost, versatility and environment compatibility. The purpose of this study was to determine the effectiveness of coagulation-flocculation process when using novel coagulant in which MgO coated with chitosan by investigating the percentage removal of several significant parameters which were turbidity, chemical oxygen demand (COD) and suspended solid. The removal efficiencies were determined throughout a series of experiments carried out using a standard jar test procedure in which three different coagulants; chitosan, MgO coated with chitosan and MgO were tested on water samples taken from Sg. Pusu. In addition, a set of experiments was designed using response surface methodology (RSM) in order to optimize adsorption of chitosan into MgO. The experiments were conducted at various concentrations of chitosan (10-30 mg/ml) and selected MgO dosage ranges (10-30 mg). From the obtained results, it was found that chitosan-MgO coagulant has good removal efficiencies of turbidity, chemical oxygen demand (COD) and suspended solids at 92%, 91%, and 98% respectively from the optimization of adsorption of chitosan-MgO. The MgO coated with chitosan is the best coagulant in this study compared to chitosan and MgO alone because of the ability of treating the river water with up to 90 % removal for all the main parameters. The results showed that coagulation-flocculation is effective as a treatment for treating river water.
    Matched MeSH terms: Rivers
  10. Yue K, De Frenne P, Van Meerbeek K, Ferreira V, Fornara DA, Wu Q, et al.
    Biol Rev Camb Philos Soc, 2022 Dec;97(6):2023-2038.
    PMID: 35811333 DOI: 10.1111/brv.12880
    Plant litter is the major source of energy and nutrients in stream ecosystems and its decomposition is vital for ecosystem nutrient cycling and functioning. Invertebrates are key contributors to instream litter decomposition, yet quantification of their effects and drivers at the global scale remains lacking. Here, we systematically synthesized data comprising 2707 observations from 141 studies of stream litter decomposition to assess the contribution and drivers of invertebrates to the decomposition process across the globe. We found that (1) the presence of invertebrates enhanced instream litter decomposition globally by an average of 74%; (2) initial litter quality and stream water physicochemical properties were equal drivers of invertebrate effects on litter decomposition, while invertebrate effects on litter decomposition were not affected by climatic region, mesh size of coarse-mesh bags or mycorrhizal association of plants providing leaf litter; and (3) the contribution of invertebrates to litter decomposition was greatest during the early stages of litter mass loss (0-20%). Our results, besides quantitatively synthesizing the global pattern of invertebrate contribution to instream litter decomposition, highlight the most significant effects of invertebrates on litter decomposition at early rather than middle or late decomposition stages, providing support for the inclusion of invertebrates in global dynamic models of litter decomposition in streams to explore mechanisms and impacts of terrestrial, aquatic, and atmospheric carbon fluxes.
    Matched MeSH terms: Rivers*
  11. Jaafar F, Na-Nakorn U, Srisapoome P, Amornsakun T, Duong TY, Gonzales-Plasus MM, et al.
    Biology (Basel), 2021 Apr 01;10(4).
    PMID: 33915909 DOI: 10.3390/biology10040286
    The king of rivers or mahseer comprises three genera: Tor, Neolissochilus, and Naziritor, under the Cyprinidae family. The Tor genus has been classified as the true mahseer due to the presence of a median lobe among the three genera. The Tor species are widely distributed across Southeast (SE) Asia, and 13 Tor species have been reported previously: Tor ater, Tor dongnaiensis, Tor douronensis, Tor laterivittatus, Tor mosal, Tor mekongensis, Tor putitora, Tor sinensis, Tor soro, Tor tambra, Tor tambroides, Tor tor and Tor yingjiangensis. However, the exact number of valid Tor species remains debatable. Different and unstandardized approaches of applying genetic markers in taxonomic identification and morphology variation within the same species have further widened the gap and ameliorated the instability of Tor species taxonomy. Therefore, synchronized and strategized research among Tor species researchers is urgently required to improve and fill the knowledge gap. This review is a current update of SE Asia's Tor species, outlining their distribution, morphology, and genetic identification. In addition, the present review proposes that there are ten valid Tor species in the SE Asian region. This list will serve as a template and standard to improve the taxonomy of the SE Asian Tor species, which could serve as a basis to open new directions in Tor research.
    Matched MeSH terms: Rivers
  12. Mohd Aqmin Abdul Wahab, Adzleen Mohmood, Nur Khaliesah Jamadon, Amir Syahir
    MyJurnal
    The trend of global under-five child mortality rate showed a steady decrease at -3.14% per year
    approaching the United Nations millennium development goals target (-4.0% reduction per year
    from 1990-2015). This rate is usually inversely proportional to the nations GDP. However, the
    progress in the recent years (2006-2012) in Malaysia has raised a disturbing concern with an
    annual average increment of +0.81% per year. Thus, there is an urgent need to identify the
    reasons of such risky ecosystem. By analyzing recorded data on river pollution from 2007-
    2012, we found that river pollution has high correlation with the gross domestic products, not at
    the same year, but for two years prior that indicates a lag time. We also found that under-five
    child mortality has strong correlation with the river pollutions. The development-pollutionhealth
    triangular cycle needs to be put in a balanced to ensure the nation prosperity and
    sustainability of the nation.
    Matched MeSH terms: Rivers
  13. Halmi, M.I.E., Baskaran Gunasekaran, Othman, A.R., Shukor, M.Y., Kamaruddin, K., Dahalan, F.A., et al.
    MyJurnal
    The volume of contaminated rivers in Malaysia continues to keep rising through the years. The
    cost of instrumental monitoring is uneconomical and prohibits schedule monitoring of
    contaminants particularly heavy metals. In this work, a rapid enzyme assay utilizing the
    molybdenum-reducing enzyme as an inhibitive assay, prepared in crude form from the
    molybdenum-reducing bacterium Serratia sp. strain DRY5 has been developed for monitoring
    the heavy metals mercury, silver, copper and chromium in contaminated waters in the Juru
    Industrial Estate. The crude enzyme extract transformed soluble molybdenum
    (phosphomolybdate) into a deep blue solution, which is inhibited by heavy metals such as
    mercury, silver, copper and chromium. The IC50 and Limits of Detection (LOD) values for
    mercury, copper, silver and cadmium were 0.245, 0.298, 0.367, 0.326, and 0.124, 0.086, 0.088
    and 0.094 mg L-1, respectively. The assay is rapid, and can be carried out in less than 10 minutes.
    In addition, the assay can be carried out at ambient temperature. The IC50 values for these heavy
    metals are more sensitive than several established assays. Water samples from various locations
    in the month of November from the Juru Industrial Estate (Penang) were tested for the presence
    of heavy metals using the developed assay. Enzyme activity was nearly inhibited for water
    samples from several locations. The presence of heavy metals was confirmed instrumentally
    using Atomic Emission Spectrometry and a Flow Injection Mercury System. The assay is rapid
    and simple and can be used as a first screening method for large scale monitoring of heavy
    metals.
    Matched MeSH terms: Rivers
  14. Naing Oo Tha, Wendy Diana Shoesmith, Chrystalle B. Y. Tan, Mohd Yusof Ibrahim, Syed Shajee Hussein
    Borneo Epidemiology Journal, 2020;1(1):45-54.
    MyJurnal
    Introduction: One of the aims outlined in Malaysia’s Health Vision 2020 is to be a nation of healthy individuals, families, and communities through an equitable, affordable, efficient, environmentally adaptable, and consumer friendly healthcare system. Sabah faces tremendous challenges to provide the best care for patients. For example, Sabah's unique geographical location and landscape, such as steep hills and rivers, is one of the challenges that health staff faces. Objectives of this study aimed to examine the prevalence of geographical accessibility, types of healthcare services, and the types of health seeking behaviour in 2 northern rural areas of Sabah to assess the geographic accessibility and availability of healthcare services.
    Materials and Methods: A community-based cross-sectional study was conducted in two rural areas in Sabah—Kudat and Pitas. Data collection was done by using questionnaire and face–to-face interviews
    Results: It was found that 48% of the study population sought healthcare and they mainly chose healthcare services from hospitals and health clinics.
    Conclusion: Half of the population in the areas studied used healthcare in the last year. The choice of using a public hospital or community health clinics was determined by distance from residence
    Matched MeSH terms: Rivers
  15. Idriss AA, Ahmad AK
    Bull Environ Contam Toxicol, 2015 Feb;94(2):204-8.
    PMID: 25564001 DOI: 10.1007/s00128-014-1452-x
    This study examined the concentration of heavy metals in 13 fish species. The results indicated that shellfish species (clams) have the highest metal concentrations, followed by demersal and pelagic fishes. The mean concentration of metals in clams are Zn 88.74 ± 11.98 µg/g, Cu 4.96 ± 1.06 µg/g, Pb 1.22 ± 0.19 µg/g, Cd 0.34 ± 0.04 µg/g dry wt. basis, whereas the same measure in fish tissues was 58.04 ± 18.51, 2.47 ± 1.21, 0.58 ± 0.27 and 0.17 ± 0.08 µg/g dry wt. basis. The concentrations of heavy metals in clams and fish tissues were still lower than the maximum allowable concentrations as suggested by the Malaysian Food Act (1983) and are considered safe for local human consumption.
    Matched MeSH terms: Rivers/chemistry*
  16. Naji A, Ismail A, Kamrani E, Sohrabi T
    Bull Environ Contam Toxicol, 2014 Jun;92(6):674-9.
    PMID: 24590446 DOI: 10.1007/s00128-014-1243-4
    Metallothionein (MT) concentrations in gill and liver tissues of Oreochromis mossambicus were determined to assess biological response of fish to levels of some metals. Metal concentrations in gill and liver tissues of O. mossambicus ranged from 0.6 to 2.6 for Cd, 16 to 52 for Zn, 0.5 to 17 for Cu and 2 to 67 for T-Hg (all in μg/g wet weight, except for T-Hg in ng/g wet weight). Accumulation of Cd, Zn, Cu and Hg (μg/g wet weight) in the liver and gills of O. mossambicus were in the order of liver > gills. The concentrations of Cd, Zn, Cu and Hg in fish tissues were correlated with MT content. The increases in MT levels from the reference area Puchong Tengah compared to the polluted area Kampung Seri Kenangan were 3.4- and 3.8-fold for gills and livers, respectively. The results indicate that MT concentrations were tissue-specific, with the highest levels in the liver. Therefore, the liver can act as a tissue indicator in O. mossambicus in the study area.
    Matched MeSH terms: Rivers/chemistry
  17. Suhaimi S, Tahir NM, Suriyati S
    Bull Environ Contam Toxicol, 2004 Dec;73(6):1094-100.
    PMID: 15674725
    Matched MeSH terms: Rivers/chemistry*
  18. Ali MF, Heng LY, Ratnam W, Nais J, Ripin R
    Bull Environ Contam Toxicol, 2004 Sep;73(3):535-42.
    PMID: 15386176
    Matched MeSH terms: Rivers
  19. Jaeger L, Uning R, Mohd Hanif N, Latif MT
    Bull Environ Contam Toxicol, 2019 Sep;103(3):374-379.
    PMID: 31230135 DOI: 10.1007/s00128-019-02662-6
    This study determines the levels of surfactants at 12 stations located in the Melaka River Estuary. This river estuary is located within a tourism area of Melaka Historical City. The concentrations of anionic and cationic surfactants in the sea surface microlayer (SML) and sub-surface water (SSW) were determined by using two colorimetric methods, methylene blue active substances (MBASs) and disulphine blue active substances (DBASs), respectively. The results showed that cationic surfactants as DBAS (ranging between 0.19 and 0.25 μmol L-1) dominated the concentrations of surfactants in SML. The enrichment factor (Ef) between MBAS and DBAS in the SML and SSW ranged between 1.0 and 2.0, and 1.0 to 1.4, respectively. There was no significant correlation (p > 0.05) between MBAS and DBAS for both SML and SSW. Nevertheless, there were strong correlations (p 
    Matched MeSH terms: Rivers
  20. Idrus FA, Basri MM, Rahim KAA, Rahim NSA, Chong MD
    Bull Environ Contam Toxicol, 2018 Mar;100(3):350-355.
    PMID: 29344698 DOI: 10.1007/s00128-018-2270-3
    This study analyzed the levels of cadmium (Cd), copper (Cu), and zinc (Zn) by the flame atomic absorption spectrophotometer (FAAS), in the muscle tissues, exoskeletons, and gills from freshwater prawn (Macrobrachium rosenbergii) (n = 20) harvested from natural habitat in Kerang River, Malaysia on 25th November 2015. Significant increase of the metals level in muscle tissue and gill (r > 0.70, p 
    Matched MeSH terms: Rivers/chemistry
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