This study focused on the isolation and characterization of high cadmium-resistant bacterial strains, possible exploitation of its cadmium-accumulation and cadmium-induced proteins. Cadmium-resistant bacterial strains designated as RZ1 and RZ2 were isolated from industrial wastewater of Penang, Malaysia. These isolates were identified as Enterobacter mori and Enterobacter sp. WS12 on the basis of phenotypic, biochemical and 16S rDNA sequence based molecular phylogenetic characteristics. Both isolates were Gram negative, cocci, and growing well in Lauria-Bertani broth medium at 35 °C temperature and pH 7.0. Results also indicated that Enterobacter mori and Enterobacter sp. WS12are capable to remove 87.75 and 85.11% of the cadmium from 100 µg ml(-1) concentration, respectively. This study indicates that these strains can be useful as an inexpensive and efficient bioremediation technology to remove and recover the cadmium from wastewater.
The identification of plant metabolites is very important for the understanding of plant physiology including plant growth, development and defense mechanism, particularly for herbal medicinal plants. The metabolite profile could possibly be used for future drug discovery since the pharmacological activities of the indigenous herbs have been proven for centuries. An untargeted mass spectrometric approach was used to identify metabolites from the leaves and stems of Impatiens balsamina using LC-DAD-MS/MS. The putative compounds are mostly from the groups of phenolic, organic and amino acids which are essential for plant growth and as intermediates for other compounds. Alanine appeared to be the main amino acid in the plant because many alanine derived metabolites were detected. There are also several secondary metabolites from the groups of benzopyrones, benzofuranones, naphthoquinones, alkaloids and flavonoids. The widely reported bioactive components such as kaempferol, quercetin and their glycosylated, lawsone and its derivatives were detected in this study. The results also revealed that aqueous methanol could extract flavonoids better than water, and mostly, flavonoids were detected from the leaf samples. The score plots of component analysis show that there is a minor variance in the metabolite profiles of water and aqueous methanolic extracts with 21.5 and 30.5% of the total variance for the first principal component at the positive and negative ion modes, respectively.
In this study the genetic diversity of local freshwater leeches (Hirudinaria spp.) was inferred using mtDNA COI gene analysis and compared with the gross external variations of 26 freshwater leech specimens obtained from the wild and leech farms. Based on a neighbor-joining tree generated from 516 COI base sequences, four distinct clades of Hirudinaria were seen with interspecific genetic divergence in the range of 7.6-14.5%. The external morphological variations based on the presence of stripes, location of gonopores, and anus separated the samples into four morphologically distinct groups matching the four clades obtained from the molecular data. Two black stripes at the ventral region were observed only in specimens found clustered with clades that contained the GenBank-reported H. manillensis, whereas the brown or dark green coloration without stripes on the ventral region was seen in samples that clustered with H. javanica and H. bpling clades.
Toxic metals in the industrial wastewaters have been liable for drastic pollution hence a powerful and economical treatment technology is needed for water purification. For this reason, some pure cellulosic materials were derived from waste fiber to obtain an economical adsorbent for wastewater treatment. Conversion of cellulose into grafting materials such as poly(methyl acrylate)-grafted cellulose was performed by free radical grafting process. Consequently, poly(hydroxamic acid) ligand was produced from the grafted cellulose. The intermediate products and poly(hydroxamic acid) ligand were analyzed by FT-IR, FE-SEM, TEM, EDX, and XPS spectroscopy. The adsorption capacity (qe) of some toxic metals ions by the polymer ligand was found to be excellent, e.g., copper capacity (qe) was 346.7 mg·g-1 at pH 6. On the other hand, several metal ions such as cobalt chromium and nickel also demonstrated noteworthy sorption capacity at pH 6. The adsorption mechanism obeyed the pseudo second-order rate kinetic model due to the satisfactory correlated experimental sorption values (qe). Langmuir model isotherm study showed the significant correlation coefficient with all metal ions (R2 > 0.99), indicating that the single or monolayer adsorption was the dominant mode on the surface of the adsorbent. This polymer ligand showed good properties on reusability. The result shows that the adsorbent may be recycled for 6 cycles without any dropping of starting sorption capabilities. This polymeric ligand showed outstanding toxic metals removal magnitude, up to 90-99% of toxic metal ions can be removed from industrial wastewater.
Matched MeSH terms: Water Purification; Waste Water
In this research, the Cu-based metal-organic framework (MOF-199) was fabricated and coated on the stainless steel mesh as substrates through sol-gel procedure. Then the coated substrates were placed in a small column known as solid-phase extraction cartridge. The SPE based coated stainless steel mesh coupled with high-performance liquid chromatography-UV detector (HPLC-UV) was used for the fast extraction, and quantification of non-steroidal anti-inflammatory drugs (NSAIDs) from human plasma and water samples. To find optimum extraction conditions, the impacts of effective parameters on analytical performance like sample pH, sample volume, type, and volume of desorption solvent were optimized. At the optimized conditions, calibration graphs of analytes were linear in the concentration range of 0.03-300 ng mL-1 for water samples, and 0.1-200 ng mL-1 for plasma samples. The correlation coefficients were in the range of 0.9938 to 0.9989. Also, the limits of detection (LODs) were from 0.01 to 0.02 ng mL-1 for water samples and 0.03 to 0.1 ng mL-1 for plasma samples. The cartridge repeatability was studied at different values, and the relative standard deviations (RSDs%) were achieved between 3.5 and 5.1%. Consequently, this procedure was successfully used in the extraction and detection of NSAIDs in real water and plasma samples with relative recoveries ranged from 93.6 to 99.6%.
Matched MeSH terms: Water Pollutants, Chemical/blood*
This paper presents the use of a commercial quartz crystal microbalance (QCM) to investigate live-cell activity in water-based toxic solutions. The QCM used in this research has a resonant frequency of 10 MHz and consists of an AT-cut quartz crystal with gold electrodes on both sides. This QCM was transformed into a functional biosensor by integrating with polydimethylsiloxane culturing chambers. Rainbow trout gill epithelial cells were cultured on the resonators as a sensorial layer. The fluctuation of the resonant frequency, due to the change of cell morphology and adhesion, is an indicator of water toxicity. The shift in the resonant frequency provides information about the viability of the cells after exposure to toxicants. The toxicity result shows distinct responses after exposing cells to 0.526 μM of pentachlorophenol (PCP) solution, which is the Military Exposure Guidelines concentration. This research demonstrated that the QCM is sensitive to a low concentration of PCP and no further modification of the QCM surface was required.
Layered organic-inorganic hybrid nanocomposite material was synthesised using 4-chlorophenoxyacetate (4CPA) as guest anion intercalated into the Zn-Al layered double hydroxide inorganic host by direct co-precipitation method at pH = 7.5 and Zn to Al molar ratio of 4. Both PXRD and FTIR results confirmed that the 4CPA was successfully intercalated into the Zn-AI-LDH interlayer. As a result, a well-ordered nanolayered organic-inorganic hybrid nanocomposite, with the expansion of the basal spacing from 8.9 angstroms in the layered double hydroxide to 20.1 angstroms in the resulting nanocomposite was observed. The FTIR spectrum of the nanocomposite (ZAC) showed that it composed spectral features of Zn-AI-LDH (ZAL) and 4CPA. The nanocomposites synthesized in this work are of mesoporous-type containing 39.8% (w/w) of 4CPA with mole fraction of Al3+ in the inorganic brucite-like layers (xAI) of 0.224. The release studies showed a rapid release of the 4CPA for the first 600 min, and more sustained thereafter. The total amount of 4CPA released from the nanocomposite interlayer into the aqueous solution were 21%, 66%, and 72% in 0.0001, 0.00025, and 0.0005 M sodium carbonate, respectively. In distilled water, about 75, 35, and 57% of 4CPA could be released in 1000 min, when the pH of the release media was set at 3, 6.25, and 12, respectively. In comparison with a structurally similar organic moiety with one more chlorine atom at the 2-position of the aromatic ring, namely 2,4-dichlorophenoxyacetate (24D), the 4CPA showed a slower release rate. The slightly bulkier organic moiety of 24D together with the presence of chlorine atom at the 2-position presumably had contributed to its higher release rate, and it seems that these factors may be exploited for tuning the release rate of intercalated guest anions with similar properties. This study suggests that layered double hydroxide can be used as a carrier for an active agent and the chemical structure of the intercalated moiety can be used to tune the desired release kinetics of the beneficial agent.
Gallic acid (GA) is a hydrophilic polyphenol which is noteworthy for strong antioxidant capacity. The drawbacks of conventional extraction approaches such as time-consuming and high processing cost are often viewed as a hurdle to extract GA from plant sources in industrial scale. Aqueous two-phase system (ATPS) is a separation approach which can be employed as an alternative to the conventional approaches. The partition behaviour of GA in an alcohol/salt ATPS was investigated in this study to aid the development of industrial scale ATPS to extract GA from natural sources. The separation of GA was characterized by determining the types of alcohol and salt, phase composition, sample load, pH of the system and addition of adjuvants applied in the alcohol/salt ATPS construction. The hydrophilic GA was targeted to the salt-rich phase of the alcohol/salt ATPS with a partition coefficient (KGA) of 25.00 ± 0.00. The optimum condition of ATPS for the maximum partition of GA was achieved in ATPS comprised of 24% (w/w) 1-propanol and 22% (w/w) phosphate salt at pH 8 with 5% (w/w) of 1 mg/mL sample loading and 2% (w/w) NaCl addition. The findings suggest that ATPS can be applied for separation of GA from various natural sources.
The catalytic properties of nanoparticles (e.g., nano zero valent iron, nZVI) have been used to effectively treat a wide range of environmental contaminants. Emerging contaminants such as endocrine disrupting chemicals (EDCs) are susceptible to degradation by nanoparticles. Despite extensive investigations, questions remain on the transformation mechanism on the nZVI surface under different environmental conditions (redox and pH). Furthermore, in terms of the large-scale requirement for nanomaterials in field applications, the effect of polymer-stabilization used by commercial vendors on the above processes is unclear. To address these factors, we investigated the degradation of a model EDC, the steroidal estrogen 17α-ethinylestradiol (EE2), by commercially sourced nZVI at pH 3, 5 and 7 under different oxygen conditions. Following the use of radical scavengers, an assessment of the EE2 transformation products shows that under nitrogen purging direct reduction of EE2 by nZVI occurred at all pHs. The radicals transforming EE2 in the absence of purging and upon air purging were similar for a given pH, but the dominant radical varied with pH. Upon air purging, EE2 was transformed by the same radical species as the non-purged system at the same respective pH, but the degradation rate was lower with more oxygen - most likely due to faster nZVI oxidation upon aeration, coupled with radical scavenging. The dominant radicals were OH at pH 3 and O2- at pH 5, and while neither radical was involved at pH 7, no conclusive inferences could be made on the actual radical involved at pH 7. Similar transformation products were observed without purging and upon air purging.
Matched MeSH terms: Water Pollutants, Chemical/chemistry*
This study aimed at purification of phycocyanin (PC) from Phormidium tergestinum using an aqueous two-phase system (ATPS) comprised of polyethylene glycol (PEG) and salts. The partitioning efficiency of PC in ATPS and the effect of phase composition, pH, crude loading, and neutral salts on purification factor and yield were investigated. Results showed that PC was selectively partitioned toward bottom phase of the system containing potassium phosphate. Under optimum conditions of 20% (w/w) PEG 4000, 10% (w/w) potassium phosphate, 20% (v/v) crude load at pH 7, with addition of 0.5% (w/w) NaCl, PC from P. tergestinum was partially purified up to 5.34-fold with a yield of 87.8%. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the molecular weight of PC was ∼19 kDa. Results from this study demonstrated ATPS could be used as a potential approach for the purification of PC from P. tergestinum.
Nutritional quality of the hepatopancreas and gonads of orange portunid mud crab, Scylla olivacea was evaluated for each gender under four treatment of different water velocities (0, 20, 40 and 60 cm s-1), in terms of nutrient reserve and nutrient for reproduction. About 56 crabs were used in this study in which fatty acids composition was analysed using gas chromatography mass-spectrometry (GC-MS). For hepatopancreas analysis, monounsaturated fatty acids (MUFAs) were present in the highest fatty acids concentration, followed by polyunsaturated fatty acids (PUFAs) and, saturated fatty acids (SFAs). However, long-chain polyunsaturated fatty acids (LC-PUFAs) were displayed in low concentration in the hepatopancreas. Total fatty acid (TFAs) composition was significantly higher at moderate velocity of 20 cm s-1 compared to other water velocity treatments. For gonad analysis, 20 cm s-1 showed the highest TFA concentration of 93.34 mg g-1 while, the lowest concentration of 3.90 mg g-1 occurred at 0 cm s-1. There were significant differences in male and female crab's fatty acids contents of gonads at all flow velocities challenged (p < 0.05). PUFAs and MUFAs were dominant while, SFAs were observed at low concentration. This study revealed that, concentration of PUFAs increased as gonad maturation increased. The decreasing concentration of hepatopancreas fatty acids over the culture period indicated that nutrient was shifted from the hepatopancreas, to be used as energy reserved to gonads for further growth of eggs and offspring. The linkages between water flow strength, hepatopancreas, and gonad fatty acids concentrations, is fundamental knowledge useful in establishing efficient habitat velocities selection which will improve aquaculture production of mud crabs with high quality broodstock.
Four tropical PSP toxins-producing dinoflagellates, Alexandrium minutum, Alexandrium tamiyavanichii, Alexandrium tamarense and Alexandrium peruvianum from Malaysian waters were studied to investigate the influences of salinity on growth and toxin production. Experiments were conducted on constant temperature 25 degrees C, 140 microE mol m(-2) s(-1) and under 14:10 light:dark photo-cycle with salinity ranged from 2 to 30 psu. The PSP-toxin congeners, GTX 1-6, STX, dcSTX, NEO and C1-C2 were analysed by high performance liquid chromatography. Salinity tolerance of the four species in decreasing order is A. minutum>A. peruvianum>A. tamarense>A. tamiyavanichii. Specific growth rates and maximum densities varied among these species with A. minutum recorded as the highest, 0.5 day(-1) and 6 x 10(4) cells L(-1). Toxin content decreased with elevated salinities in A. minutum, the highest toxin content was about 12 fmole cell(-1) at 5 psu. In A. tamiyavanichii, toxin content peaked at optimal growth salinity (20 and 25 psu). Toxin content of A. tamarense, somehow peaked at sub-optimal growth salinity (15 and 30 psu). Results of this study implied that salinity fluctuation not only influenced the growth physiology but also toxin production of these species.
Toxorhynchites splendens larvae are a natural predator of dengue vector mosquito larvae, Aedes albopictus. This study was carried out to evaluate the predation rate of Tx. splendens third instar larvae on Ae. albopictus larvae in 24 h. Each predator was offered prey at a density between 10 to 50 individuals. Predation rate of Tx. splendens were also tested with two manipulated factors; various types of container and different water volumes. The experiment was evaluated in man-made containers (tin cans, plastic drinking glasses and rubber tires) and natural container (bamboo stumps) which were filled with different water volumes (full, half full, 1/4 full, and 1/8 full). The prey density and the characteristics of the container were found as significant factors which influence the predation rate of Tx. splendens. The predator consumed significantly more prey at higher prey densities (40 and 50 preys) compared to the lowest density (10 preys) (F=3.935, df=4, p=0.008). The results showed significantly higher consumption in horizontal shaped container of rubber tire than in vertical shape of bamboo stumps (F=3.100, df=3, p=0.029). However, the water volume had no significant effect on predation rate of Tx. splendens (F=1.736, df=3, p=0.162). We generally suggest that Tx. splendens is best to be released in discarded tires or any other containers with horizontal shape design with wide opening since Tx. splendens can become more effective in searching prey in this type of container design. This predator is also a suitable biocontrol candidates to be introduced either in wet and dry seasons in Malaysia.
The use of ice cubes in beverages is common among patrons of food outlets in Malaysia although its safety for human consumption remains unclear. Hence, this study was designed to determine the presence of faecal coliforms and several useful water physicochemical parameters viz. free residual chlorine concentration, turbidity and pH in ice cubes from 30 randomly selected food outlets in Kubang Kerian, Kelantan. Faecal coliforms were found in ice cubes in 16 (53%) food outlets ranging between 1 CFU/100mL to >50 CFU/ 100mL, while in the remaining 14 (47%) food outlets, in samples of tap water as well as in commercially bottled drinking water, faecal coliforms were not detected. The highest faecal coliform counts of >50 CFU/100mL were observed in 3 (10%) food outlets followed by 11-50 CFU/100mL and 1-10 CFU/100mL in 7 (23%) and 6 (20%) food outlets, respectively. All samples recorded low free residual chlorine concentration (<0.10mg/L) with the pH ranging between 5.5 and 7.3 and turbidity between 0.14-1.76 NTU. Since contamination by faecal coliforms was not detected in 47% of the samples, tap water and commercially bottled drinking water, it was concluded that (1) contamination by faecal coliforms may occur due to improper handling of ice cubes at the food outlets or (2) they may not be the water sources used for making ice cubes. Since low free residual chlorine concentrations were observed (<0.10mg/ L) in all samples as well as in both tap water and commercially bottled drinking water, with the pH ranged between 5.5-7.3, ineffective disinfection of water source as a contributing factor to such high counts of faecal coliforms in ice cubes also could not be ruled out. Therefore, a periodical, yet comprehensive check on the food outlets, including that of ice cube is crucial in ensuring better food and water for human consumption.
This study reports the detection of Acanthamoeba and Naegleria species in 14 swimming pools around Petaling Jaya and Kuala Lumpur, Malaysia. Sampling was carried out at 4 sites (the platforms (P), wall (W), 1 meter from the wall (1) and middle (2)) of each swimming pool. These free living amoebae (FLA) were detected under light and inverted microscopes after being cultured on the surface of non-nutrient agar lawned with Escherichia coli. Acanthamoeba species were detected in higher number of culture plates from all sampling sites of all the swimming pools. While Naegleria, were detected in fewer culture plates at 3 sampling sites (absent at site P) of 8 swimming pools. This suggested that the thick double-walled cysts of Acanthamoeba were more resistant, thus remaining viable in the dry-hot areas of the platforms and in chlorinated water of the swimming pools whereas Naegleria cysts, that are fragile and susceptible to desiccation, preferred watery or moist areas for growth and proliferation. The prevalence of both FLA was highest at site W (76.2%), followed by site 1 (64.7%), lowest at site 2 (19.4%), and could be detected at all 3 sampling levels (top, middle and bottom) of these 3 sites. The surface of site W might act as a bio-film that accumulated all kinds of microbes providing sufficient requirement for the FLA to develop and undergo many rounds of life cycles as well as moving from top to bottom in order to graze food. Other factors such as human activities, the circulating system which was fixed at all swimming pools, blowing wind which might carry the cysts from surroundings and the swimming flagellate stage of Naegleria could also contribute to the distribution of the FLA at these sampling sites. Both FLA showed highest growth (80.4%) at room temperature (25-28 ºC) and lesser (70.0%) at 37 ºC which might be due to the overgrowth of other microbes (E. coli, fungi, algae, etc). While at 44 ºC, only Acanthamoeba species could survive thus showing that our swimming pools are free from potentially pathogenic Naegleria species. However, further study is needed in order to confirm the virulence levels of these amoebae isolates.
Leptospirosis is recognized as one of the important zoonotic diseases in the world including Malaysia. A total of 145 soil and water samples were collected from selected National Service Training Centres (NSTC) in Kelantan and Terengganu. The samples were inoculated into modified semisolid Ellinghausen McCullough Johnson Harris (EMJH) medium, incubated at room temperature for 1 month and examined under the dark-field microscope. Positive growth of the leptospiral isolates were then confirmed with 8-Azaguanine Test, Polymerase Chain Reaction (PCR) assay and Microscopic Agglutination Test (MAT). Fifteen cultures (10.34%) exhibited positive growths which were seen under dark field microscope whilst only 20% (3/15) were confirmed as pathogenic species. based on 8-Azaguanine Test and PCR. Serological identification of the isolates with MAT showed that hebdomadis was the dominant serovar in Terengganu. Pathogenic leptospires can be detected in Malaysian environment and this has the potential to cause an outbreak. Therefore, precautionary steps against leptospirosis should be taken by camp authorities to ensure the safety of trainees.
Transmission of soil-transmitted helminthes infection is by faecal oral route, and is influenced by food preference. Kelantanese love to consume ulam which are raw vegetables and herbs. Some of the herbs grow on grounds with high humidity and are abundant near drainage areas, these are also places with higher likelihood of harbouring viable parasite ova. The aim of this study was to determine the prevalence of soiltransmitted helminthes in vegetables, herbs and fruits found in our local setting. The results by microscopy showed that there was no helminthes ovum or protozoan parasite in the samples. However, Strongyloides stercoralis rhabdatiform larvae were identified in water samples used to wash pegaga, kesum and water spinach, and the number of larvae observed were 152, 9 and 16 respectively. Analysis by real-time PCR confirmed the microscopic observation of this helminth. This study highlighted that vegetables and herbs are likely sources of Strongyloides stercoralis infection in Kota Bharu, Kelantan. Thus vegetable sellers as well as the food handlers are the two important groups who are at high risk of acquiring the infection.
Legionella pneumophila are intracellular pathogens, associated with human disease, attributed to the presence and absence of certain virulent genes. In this study, virulent gene loci (lvh and rtxA regions) associated with human disease were determined. Thirty-three cooling tower water isolates, isolated between 2004 to 2006, were analyzed for the presence of these genes by PCR method. Results showed that 19 of 33 (57.5%) of the L. pneumophila serogroup 1 isolates have both the genes. Six (18.2%) of the isolates have only the lvh gene and 2 (6.1%) of the isolates have only the rtxA gene. However, both genes were absent in 6 (18.2%) of the L. pneumophila isolates. The result of our study provides some insight into the presence of the disease causing L. pneumophila serogroup 1 in the environment. Molecular epidemiological studies will provide better understanding of the prevalence of the disease in Malaysia.
This entomological study was conducted in a man-made freshwater pond in a palm oil plantation in Tanjung Sepat, Selangor from 23 July 2007 by using pig (Sus scrofa) as a carcass model. A 1.5 month old piglet (5 kg), which died of asphyxia after being accidentally crushed by its mother, was thrown into a pond. Observation was made for ten days; one visit per day and climatological data were recorded. On the first two days, the piglet carcass sunk to the bottom of the pond. The carcass floated to the surface on the third day but no fly activities were seen. The blow fly, Chrysomya megacephala and Chrysomya rufifacies started to oviposit on the fourth day. Other than adult flies, a spider (Arachnida) was also observed on the carcass. Bubbles accumulated at the mouthpart, and the abdomen was greenish black. A lot of blow fly eggs were seen on the body surface on the fifth day (floating decay), along with first and second instars C. megacephala crawling under the piglet's skin. On the sixth day, adult blow fly, C. megacephala,and C. rufifacies,and muscid flies, Ophyra spinigera and Musca domestica were observed on to the carcass. High numbers of first and second instars of flies were observed wandering around the body surface with C. megacephala larvae being the predominant species. Two prominent maggot masses occurred on seventh and eighth days. Bloated deterioration stage began on day eighth exposing rib bones, humerus bones and intestines. Carcass was partially sinking and the maggot masses were at the water level. On day ninth, the carcass was partially sinking and three maggot masses were observed on the exposed surface. There were very few adult flies, including a scarab beetle was sighted on the carcass at this stage. The carcass along with the maggots sunk on day tenth, leaving an oily layer on the water surface.
This is a cross-sectional study conducted from January to September 2004 in a group of school children aged 8 -10 years old. The schools and study subjects were selected using stratified systematic sampling technique. A total of 44 schools and 1100 subjects were selected from schools with iodinator and schools without iodinator. Samples collected were spot urine and drinking water. Dietary and iodised water consumption data were obtained from interviews. A total of 931 subjects (84.6%) responded; 558 (50.7%) from schools with iodinator and 373 (33.9%) from schools without iodinator. Results showed that in more than half (53.8%) of the schools with iodinators, mean water iodine level was below 25 microg/L. The study population in Terengganu was found to be mildly iodine deficient with an overall median urine iodine concentration (uIC) of 74 microg/L. Based on WHO criteria, 4.1% with uIC <20 microg/L (severe), 19.5% with uIC between 20-49 microg/L (moderate), 49.2% with uIC between 50-99 microg/L (mild) and 27.2% was iodine sufficient with uIC >100 microg/L. Majority of the study subjects were found to have high seafood intake (> 90%) and low in goitrogen food intake. This study suggests water iodinator system may not be a suitable method of supplying iodine and an alternative is needed in order to eradicate the iodine deficiency problem seen in some parts of Malaysia.