The growing interest in the environmental occurrence of veterinary and human pharmaceuticals is essentially due to their possible health implications to humans and ecosystem. This study assesses the occurrence of human pharmaceuticals in a Malaysian tropical aquatic environment taking a chemometric approach using cluster analysis, discriminant analysis and principal component analysis. Water samples were collected from seven sampling stations along the heavily populated Langat River basin on the west coast of peninsular Malaysia and its main tributaries. Water samples were extracted using solid-phase extraction and analyzed using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) for 18 pharmaceuticals and one metabolite, which cover a range of six therapeutic classes widely consumed in Malaysia. Cluster analysis was applied to group both pharmaceutical pollutants and sampling stations. Cluster analysis successfully clustered sampling stations and pollutants into three major clusters. Discriminant analysis was applied to identify those pollutants which had a significant impact in the definition of clusters. Finally, principal component analysis using a three-component model determined the constitution and data variance explained by each of the three main principal components.
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.
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.
Landfills are sources of groundwater and soil pollution due to the production of leachate and its migration through refuse. This study was conducted in order to determine the extent of groundwater and soil pollution within and around the landfill of Seri Petaling located in the State of Selangor, Malaysia. The condition of nearby surface water was also determined. An electrical resistivity imaging survey was used to investigate the leachate production within the landfill. Groundwater geochemistry was carried out and chemical analysis of water samples was conducted upstream and downstream of the landfill. Surface water was also analyzed in order to determine its quality. Soil chemical analysis was performed on soil samples taken from different locations within and around the landfill in the vadose zone (unsaturated zone) and below the water table (in the soil saturated zone). The resistivity image along line L-L1 indicated the presence of large zones of decomposed waste bodies saturated with highly conducting leachate. Analysis of trace elements indicated their presence in very low concentrations and did not reflect any sign of heavy metal pollution of ground and surface water or of soil. Major ions represented by Na, K, and Cl were found in anomalous concentrations in the groundwater of the downstream bore hole, where they are 99.1%, 99.2%, and 99.4%, respectively, higher compared to the upstream bore hole. Electrical conductivity (EC) was also found in anomalous concentration downstream. Ca and Mg ions represent the water hardness (which is comparatively high downstream). There is a general trend of pollution towards the downstream area. Sulfates (SO4) and nitrates (NO3) are found in the area in low concentrations, even below the WHO standards for drinking water, but are significantly higher in the surface water compared to the groundwater. Phosphate (PO4) and nitrite (NO2), although present in low levels, are significantly higher at the downstream. There is no significant difference in the amount of fluoride (F) in the different locations. In the soil vadose zone, heavy metals were found to be in their typical normal ranges and within the background concentrations. Soil exchangeable bases were significantly higher in the soil saturated zone compared to the vadose zone, and no significant difference was obtained in the levels of inorganic pollutants. With the exception of Cd, the concentration ranges of all trace elements (Cu, Zn, Cr, Pb, and Ni) of Seri Petaling landfill soils were below the upper limits of baseline concentrations published from different sources.
Aquitalea sp. USM4 (JCM 19919) was isolated from a freshwater sample at Lata Iskandar Waterfall in Perak, Malaysia. It is a rod-shaped, gram-negative bacterium with high sequence identity (99%) to Aquitalea magnusonii based on 16S rRNA gene analysis. Aquitalea sp. USM4 also possessed a PHA synthase gene (phaC), which had amino acid sequence identity of 77-78% to the PHA synthase of Chromobacterium violaceum ATCC12472 and Pseudogulbenkiania sp. NH8B. PHA biosynthesis results showed that wild-type Aquitalea sp. USM4 was able to accumulate up to 1.5 g/L of poly(3-hydroxybutyrate), [P(3HB)]. The heterologous expression of the PHA synthase gene of Aquitalea sp. USM4 (phaCAq) in Cupriavidus necator PHB(-)4 had resulted in PHA accumulation up to 3.2 g/L of P(3HB). It was further confirmed by (1)H nuclear magnetic resonance (NMR) analysis that Aquitalea sp. USM4 and C. necator PHB(-)4 transformant were able to produce PHA containing 3-hydroxyvalerate (3HV), 4-hydroxybutyrate (4HB) and 3-hydroxy-4-methylvalerate (3H4MV) monomers from suitable precursor substrates. Interestingly, relatively high PHA synthase activity of 863 U/g and 1402 U/g were determined in wild-type Aquitalea sp. USM4 and C. necator PHB(-)4 transformant respectively. This is the first report on the member of genus Aquitalea as a new PHA producer as well as in vitro and in vivo characterization of a novel PHA synthase from Aquitalea sp. USM4.
Heavy metals in the aquatic environment have to date come mainly from naturally occurring geochemical materials. However, this has been enhanced by human activity such as gold mining in the case of heavy metal pollution in Sg Sarawak Kanan. The high suspended solid loads in the river have quite efficiently removed most soluble metals from the water and trapped them in the bottom sediment. Three freshwater mollusc species were collected at the point source of the heavy metal pollutants and analysed for the heavy metal contents in their tissues and shells. Two of the mollusc species (Brotia costula and Melanoides tuberculata) are purely freshwater species while the Clithon sp. nr retropictus is able to survive in fresh and brackish water environments. The Brotia costula and the Clithon sp. are the edible species which are sold in the market. Accumulation of As, Cu, Fe, Se and Zn in all the three mollusc species were determined and the level of As in the tissues of Brotia costula and the Clithon sp. was much higher than the permissible level for human consumption. The mollusc species also demonstrated different preferences for the uptake of different metals. Variations in the heavy metal contents in the shell and tissues of the same species were also observed.
Gadilam river basin has gained its importance due to the presence of Neyveli Lignite open cast mines and other industrial complexes. It is also due to extensive depressurization of Cuddalore aquifer, and bore wells for New Veeranam Scheme are constructed downstream of the basin. Geochemical indicators of groundwater were used to identify the chemical processes that control hydrogeochemistry. Chemical parameters of groundwater such as pH, electrical conductivity, total dissolved solids, sodium (Na(+)), potassium (K(+)), calcium (Ca(+)), magnesium (Mg(+)), bicarbonate (HCO(-)(3)), sulfate (SO(-)(4)), phosphate (PO(-)(4)), and silica (H(4)SiO(4)) were determined. Interpretation of hydrogeochemical data suggests that leaching of ions followed by weathering and anthropogenic impact controls the chemistry of the groundwater. Isotopic study reveals that recharge from meteoric source in sedimentary terrain and rock-water interaction with significant evaporation prevails in hard rock region.
Little is known on the biosafety level of Vibrio spp. in freshwater fish in Malaysia. The purpose of this study was to investigate the prevalence and concentration of Vibrio spp. and V. parahaemolyticus in
freshwater fish using the Most Probable Number-Polymerase Chain Reaction (MPN-PCR) method. The study was conducted on 150 samples from two types of freshwater fish commonly sold at hypermarkets, i.e. Pangasius hypophthalmus (catfish) and Oreochromis sp. (red tilapia). Sampling was done on the flesh, intestinal tract and gills of each fish. The prevalence of Vibrio spp. and V. parahaemolyticus was found to be 98.67% and 24% respectively with higher percentages detected in samples from the gills followed by the intestinal tract and flesh. Vibrio spp. was detected in almost all red tilapia and catfish samples. V. parahaemolyticus was detected in 25% of the catfish samples compared to 22.6% of red tilapia fish. The density of Vibrio spp. and V. parahaemolyticus in the samples ranged from 0 to 1.1x107 MPN/g. Although the maximum value was 1.1x107 MPN/g, most samples had microbial loads ranging from 0 to >104 MPN/g. The outcome on the biosafety assessment of Vibrio spp. and V. parahaemolyticus in freshwater fish indicates another potential source of food safety issues to consumers.
Ovitrap surveillance was initiated for eight continuous weeks to determine the distribution and abundance of Aedes sp. mosquitoes in the University of Malaya campus, Kuala Lumpur, and the impact of meteorological conditions on the Aedes populations. Two study areas within the campus were selected: Varsity Lake and Seventh Residential College. The abundance of Aedes populations in Varsity Lake was indicated by ovitrap index (OI) which ranged from 60.00%-90.00%. The mean number of larvae per ovitrap of Aedes albopictus in Varsity Lake ranged from 11.23+/-2.42-43.80+/-6.22. On the other hand, the outdoor OI for Seventh Residential College ranged from 73.33%-93.33%, respectively, while the mean number larvae per ovitrap for this area ranged from 19.33+/-4.55-35.27+/-5.46, respectively. In addition, the indoor OI of Seventh Residential College ranged from 0.00%-30.00%, while the mean number of larvae per ovitrap for Ae. albopictus ranged from 0-5.90+/-3.55. There was no significant difference (p>0.05) of Ae. albopictus population between Varsity Lake and Seventh Residential College. The studies showed a correlation between OI and mean number of larvae per ovitrap for outdoor Ae. albopictus populations in Varsity Lake and Seventh Residential College (r=0.794). There was also a correlation between the mean larvae number per ovitrap of Ae. albopictus obtained from eight weeks indoor ovitrap surveillance in Seventh Residential College with rainfall (r=0.584). However, there was no correlation between the mean larvae number per ovitrap of Ae. albopictus in both study areas with temperature and relative humidity. Aedes aegypti mosquitoes were found neither indoor nor outdoor in both study areas. This study indicated that the principal dengue vector in the university campus was most likely Ae. albopictus.
Land use plays a significant role in determining the spatial patterns of water quality in the Johor River Basin (JRB), Malaysia. In the recent years, there have been several occurrences of pollution in these rivers, which has generated concerns over the long-term sustainability of the water resources in the JRB. Specifically, this water resource is a shared commodity between two states, namely, Johor state of Malaysia and Singapore, a neighbouring country adjacent to Malaysia. Prior to this study, few research on the influence of land use configuration on water quality have been conducted in Johor. In addition, it is also unclear how water quality varies under different seasonality in the presence of point sources. In this study, we investigated the influence of land use and point sources from wastewater treatment plants (WWTPs) on the water quality in the JRB. Two statistical techniques - Multivariate Linear Regression (MLR) and Redundancy Analysis (RA) were undertaken to analyse the relationships between river water quality and land use configuration, as well as point sources from WWTPs under different seasonality. Water samples were collected from 49 sites within the JRB from March to December in 2019. Results showed that influence from WWTPs on water quality was greater during the dry season and less significant during the wet season. In particular, point source was highly positively correlated with ammoniacal‑nitrogen (NH3-N). On the other hand, land use influence was greater than point source influence during the wet season. Residential and urban land use were important predictors for nutrients and organic matter (chemical oxygen demand); and forest land use were important sinks for heavy metals but a significant source of manganese.
We used a combined microscopy-molecular approach to determine the occurrence and identities of waterborne Giardia sp. cysts isolated from 18 separate, 10l grab samples collected from a Malaysian zoo. Microscopy revealed that 17 of 18 samples were Giardia cyst positive with concentrations ranging from 1 to 120 cysts/l. Nine (52.9%) of the 17 cyst positive samples produced amplicons of which 7 (77.8%) could be sequenced. Giardia duodenalis assemblage A (6 of 7) and assemblage B (1 of 7), both infectious to humans, were identified at all sampling sites at the zoo. The presence of human infectious cysts raises public health issues, and their occurrence, abundance and sources should be investigated further. In this zoo setting, our data highlight the importance of incorporating environmental sampling (monitoring) in addition to routine faecal examinations to determine veterinary and public health risks, and water monitoring should be considered for inclusion as a separate element in hazard analysis, as it often has a historical (accumulative) connotation.
Nine 50-l surface water samples from a Malaysian recreational lake were examined microscopically using an immunomagnetisable separation-immunofluorescent method. No Cryptosporidium oocysts were detected, but 77.8% of samples contained low numbers of Giardia cysts (range, 0.17-1.1 cysts/l), which were genetically characterised by SSU rRNA gene sequencing. Genotype analyses indicated the presence of Giardia duodenalis assemblage A suggesting potential risk to public health. The present study represents the first contribution to our knowledge of G. duodenalis assemblages in Malaysian recreational water.
Cryptosporidium and Giardia are major causes of diarrhoeal diseases of humans worldwide, and are included in the World Health Organisation's 'Neglected Diseases Initiative'. Cryptosporidium and Giardia occur commonly in Malaysian human and non-human populations, but their impact on disease, morbidity and cost of illness is not known. The commonness of contributions from human (STW effluents, indiscriminate defaecation) and non-human (calving, lambing, muck spreading, slurry spraying, pasturing/grazing of domestic animals, infected wild animals) hosts indicate that many Malaysian environments, particularly water and soil, are sufficiently contaminated to act as potential vehicles for the transmission of disease. To gain insight into the morbidity and mortality caused by human cryptosporidiosis and giardiasis, they should be included into differential diagnoses, and routine laboratory testing should be performed and (as for many infectious diseases) reported to a centralised public health agency. To understand transmission routes and the significance of environmental contamination better will require further multidisciplinary approaches and shared resources, including raising national perceptions of the parasitological quality of drinking water. Here, the detection of Cryptosporidium and Giardia should be an integral part of the water quality requirement. A multidisciplinary approach among public health professionals in the water industry and other relevant health- and environment-associated agencies is also required in order to determine the significance of Cryptosporidium and Giardia contamination of Malaysian drinking water. Lastly, adoption of validated methods to determine the species, genotype and subgenotype of Cryptosporidium and Giardia present in Malaysia will assist in developing effective risk assessment, management and communication models.
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.
Toxic cyanobacteria blooms are increasing in magnitude and frequency worldwide. However, this issue has not been adequately addressed in Malaysia. Therefore, this study aims to better understand eutrophication levels, cyanobacteria diversity, and microcystin concentrations in ten Malaysian freshwater lakes. The results revealed that most lakes were eutrophic, with total phosphorus and total chlorophyll-a concentrations ranging from 15 to 4270 µg L(-1) and 1.1 to 903.1 µg L(-1), respectively. Cyanobacteria were detected in all lakes, and identified as Microcystis spp., Planktothrix spp., Phormidium spp., Oscillatoria spp., and Lyngbya spp. Microcystis spp. was the most commonly observed and most abundant cyanobacteria recorded. Semi-quantitative microcystin analysis indicated the presence of microcystin in all lakes. These findings illustrate the potential health risk of cyanobacteria in Malaysia freshwater lakes, thus magnifying the importance of cyanobacteria monitoring and management in Malaysian waterways.
The aim of this study was to determine the occurrence of free-living amoebae (FLA) in Peninsular Malaysia and to compare different methodologies to detect them from water samples. Water samples were collected from tap water, recreational places, water dispensers, filtered water, etc. and tested for FLA using both cultivation and polymerase chain reaction (PCR) via plating assays and centrifugation methods. Amoebae DNA was extracted using Instagene matrix and PCR was performed using genus-specific primers. Of 250 samples, 142 (56.8%) samples were positive for presence of amoebae, while 108 (43.2%) were negative. Recreational water showed higher prevalence of amoebae than tap water. PCR for the plating assays revealed the presence of Acanthamoeba in 91 (64%) samples and Naegleria in 99 (70%) of samples analysed. All samples tested were negative for B. mandrillaris. In contrast, the centrifugation method was less effective in detecting amoebae as only one sample revealed the presence of Acanthamoeba and 52 (29%) samples were positive for Naegleria. PCR assays were specific and sensitive, detecting as few as 10 cells. These findings show the vast distribution and presence of FLA in all 11 states of Peninsular Malaysia. Further studies could determine the possible presence of pathogenic species and strains of free-living amoebae in public water supplies in Malaysia.
The present study is aimed to evaluate the effects of sub-acute toxicity testing of copper sulphate (CuSO4), on behavioural, histological and biochemical changes of the Oreochromis mossambicus (black tilapia) blood tissues. The effects were assessed according to the previous results on sub-acute toxicity test after exposing fish to several concentrations (0.0, 2.5, 5.0, and 10.0 mg/L). The observations of scanning electron microscope, and transmission electron microscope studies revealed severe histopathological changes on the surface and the cellular changes in blood tissues, respectively. The morphological alterations in blood involved irregular structure of red blood cell and blood clot formation. CuSO4 affected the biochemical alteration of the blood cholinesterase also known as serum cholinesterase (ChE). Blood ChE inhibited up to 80% of activity when exposed to 10.0 mg/L CuSO4. The findings from this study can further improve the quality standards of aquaculture industry and the fundamental basis in selecting suitable strains among freshwater fish species to be used as bioindicator.
Evaporation of vaporize organic liquid has ecological consequences when the compounds are introduced into both freshwater and marine environments through industrial effluents, or introduced directly into the air from industrial unit processes such as bioreactors and cooling towers. In such cases, a rapid and simple method are needed to measure physicochemical properties of the organic liquids. The Reversed-Flow Gas Chromatography (RF-GC) sampling technique is an easy, fast and accurate procedure. It was used to measure the diffusion coefficients of vapors from liquid into a carrier gas and at the same time to determine the rate coefficients for the evaporation of the respective liquid. The mathematical expression describing the elution curves of the samples peaks was derived and used to calculate the respective parameters for the selected liquid pollutants selected such as methanol, ethanol, 1-propanol, 1-butanol, n-pentane, n-hexane, n-heptane and n-hexadecane, evaporating into the carrier gas of nitrogen. The values of diffusion coefficients found were compared
with those calculated theoretically or reported in the literature. The values of evaporation rate were used to determine the activation energy of respective samples using Arrhenius equation. An interesting finding of this work is by using an alternative mathematical analysis based on equilibrium at the liquid-gas interphase, the comparison leads to profound
agreement between theoretical values of diffusion coefficients and experimental evidence.
This study was conducted to investigate the effects of dietary inclusion of Spirulina platensis on growth performance and hematological parameters of juvenile Asian sea bass (Lates calcarifer) reared in a freshwater culture system. Five experimental diets were prepared by replacing fish meal protein with the microalga at replacement levels of 5% (SP5), 10% (SP10), 20% (SP20) and 30% (SP30), and the substitution effect was compared with a control diet (Con) in which fish meal was the sole protein. Fish were stocked in net cages placed in a 150-ton tank with a stocking density of 20 fish per cage. After 8 weeks of feeding trial, the fish did not show any significant differences in growth performance but numerically higher weight gain and specific growth rate were achieved in the fish stock fed diet SP10 compared to other treatments. Feed conversion ratio and survival rate of fish were significantly affected by the inclusion of Spirulina in the diets. Except for crude ash content, whole-body proximate composition of the experimental fish was also significantly influenced by the diets. Regarding the effects of diets on blood parameters, only hematocrit, hemaglobin, HDL-c and AST were significantly affected by the inclusion of Spirulina in the diets. This study demonstrated that Spirulina could replace up to 10% of FM protein in practical diets of juvenile Asian sea bass without negative effects on growth performance. However, replacement of fish meal with Spirulina meal at 5% might be considered for commercial use considering a significant decrease in survival above this value.
Muscle and feather in tissue of 40 juveniles and 40 adult green-lipped mussel Perna veridis (L.) collected from Muar Estuary, Johor were analyzed for copper (Cu), cadmium (Cd), lead (Pb) and zinc (Zn) concentration using a fast and sensitive Inductively Coupled Plasma Mass Spectrometer (ICP-MS). In this study, the average concentration of Cu was 8.96 microg g(-1) dry weights, Cd with 0.58 microg g(-1) dry weight, Pb averaging 2.28 microg g(-1) dry weights and Zn averaged to 86.73 microg g(-1) dry weight. The highest accumulation of metal studied was found in feather sample compared to the muscle. The positive relationship of Cu, Cd, Pb and Zn with P. virdis length suggesting that the accumulation of these metals were formed in the mussel. In all cases, metal levels found were lower than the guideline of international standards of reference and the examined bivalve were not associated with enhanced metal content in their tissues and were safe within the limits for human consumption.