There are numerous commercial applications of microalgae nowadays owing to their vast biotechnological and economical potential. Indisputably, astaxanthin is one of the high value product synthesized by microalgae and is achieving commercial success. Astaxanthin is a keto-carotenoid pigment found in many aquatic animals including microalgae. Astaxanthin cannot be synthesized by animals and provided in the diet is compulsory. In this study, the production of astaxanthin by the freshwater microalgae Chlorella sorokiniana and marine microalgae Tetraselmis sp. were studied. The relationship between growth and astaxanthin production by marine and freshwater microalgae cultivated under various carbon sources and concentrations, environmental conditions and nitrate concentrations was investigated in this study. Inorganic carbon source and low nitrate concentration favored the growth and production of astaxanthin by the marine microalgae Tetraselmis sp. and the freshwater microalgae Chlorella sorokiniana. Outdoor cultivation enhanced the growth of microalgae, while indoor cultivation promoted the formation of astaxanthin. The results indicated that supplementation of light, inorganic carbon and nitrate could be effectively manipulated to enhance the production of astaxanthin by both microalgae studied.
Tooth wear is the loss of tooth tissue and structures not due to caries. It can occur in various forms either attrition, abrasion, erosion, noncaries cervical lesion (NCCL) or a combination of two or more forms. The objective of this study was to determine the patterns and associated aetiologies of tooth wear among adults in Kelantan, Malaysia. This crosssectional study involved 81 adults with tooth wear which was visually assessed using the Smith and Knight Tooth Wear Index (TWI). A questionnaire was used to seek putative aetiologies of the wear. Data were analyzed and the results were expressed as frequencies and percentages. Six thousand three hundred and eighty four tooth surfaces were examined in 1596 teeth. 17.4% surfaces had tooth wear; 80% scored 1, 18% scored 2 and 2% scored 3. Among the 81 cases of tooth wear, 29 (35.8%) had abrasion; 25 (30.9%) had attrition; 1(1.2%) had erosion while 26 (32.1%) had the combined type. Among those with abrasion, majority had the habit of eating freshwater clams (Corbicula fluminea) as local delicacy where most of the times people use their teeth to pry open the clam shells. Erosion was related to the pooling of carbonated drinks or beverages in the mouth before swallowing. In conclusion, most adults experienced abrasion and the most common possible associated aetiology is the way of eating clams.
A promising method of Carbon dioxide (CO2) valorization is to use green microalgae photosynthesis to process biofuel. Two Phase Partitioning Bioreactors (TPPBR) offer the possibility to use non-aqueous phase liquids (NAPL) to enhance CO2 solubility; thus making CO2 available to maximize algae growth. This requires relatively less toxic hydrophobic Ionic Liquids (ILs) that comprise a new class of ionic compounds with remarkable physicochemical properties and thus qualifies them as NAPL candidates. This paper concerns the synthesis of ILs with octyl and butyl chains as well as different cations containing aromatic (imidazolium, pyridinium) and non-aromatic (piperidinum, pyrrolidinium) rings for CO2 absorption studies. The authors measured their respective toxicity levels on microalgae species, specifically, Scenedesmus quadricauda, Chlorella vulgaris and Botryococcus braunii. Results revealed that octyl-based ILs were more toxic than butyl-based analogues. Such was the case for bmim-PF6 at double saturation with an absorbance of 0.11, compared to Omim-PF6 at 0.17, bmim-NTf2 at 0.02, and Omim-NTf2 at 0.14, respectively. CO2 uptake results for ILs bearing octyl-based chains compared to the butyl analog were 54% (nCO2/nIL) (i.e., moles of CO2 moles of IL) and 38% (nCO2/nIL), respectively. Conclusively, 1-butyl-1-methylpiperidinium absorbed 13% (nCO2/nIL) and appeared the least toxic, having an absorbance of 0.25 at 688 nm (double saturation at 7 d) compared to 1-butyl-3-methylimidazolium, which showed the highest toxicity with zero absorbance. Accordingly, these findings suggest that 1-butyl-1-methylpiperidinium is capable of transporting CO2 to a system containing green microalgae without causing significant harm; thus allowing its use in TPPBR technology.
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.
By convention, dissolved trace elements in the river water are considered to be the fraction that passes through a 0.45 μm filter. However, several researchers have considered filtration cut-off other than 0.45 μm for the separation of dissolved trace elements from particulate fraction. Recent research indicated that trace elements could exist in particulate form as colloids and natural nanoparticles. Moreover, the trace elements in the continental dust (aerosols) constitute a significant component in their geochemical cycling. Due to their high mobility, the trace elements in the micron and sub-micron scale have biogeochemical significance in the coastal zone. In this context, this study focuses on the highly mobile fraction of trace elements in particulates (<11 μm) and dissolved form in the Lower Baram River. A factor model utilizing trace elements in the dissolved and mobile phase in the particulates (<11 μm) along with water column characteristics and the partition coefficient (Kd) of the trace elements indicated a more significant role for manganese oxyhydroxides in trace element transport. Perhaps, iron oxyhydroxides play a secondary role. The factor model further illustrated the dissolution of aluminium and authigenic clay formation. Except for Fe and Al, the contamination risk of mobile trace elements in particulates (<11 μm) together with dissolved form are within the permissible limits of the Malaysian water quality standards during monsoon (MON) and postmonsoon (POM) seasons.
During several surveys made in the region of the lower Fly River and delta, Papua New Guinea, nine species of oxudercine gobies (Gobiidae: Oxudercinae) were recorded: Boleophthalmus caeruleomaculatus, Oxuderces wirzi, Periophthalmodon freycineti, Periophthalmus darwini, Periophthalmus novaeguineaensis, Periophthalmus takita, Periophthalmus weberi, Scartelaos histophorus and Zappa confluentus. An exploratory multivariate analysis of their habitat conditions discriminated five guilds, differentially distributed in habitats with different quantities of environmental water and three guilds corresponding to different levels of salinity. A partial correspondence between phylogenetic and ecological categories suggested the presence of parallel adaptive radiations within different genera. In particular, the species found in the most terrestrial habitats (P. weberi) was also found in the widest range of conditions, suggesting that colonization of extreme semi-terrestrial and freshwater habitats by this species was facilitated by eurytypy. It is proposed that these findings provide insight into convergent adaptations for the vertebrate eco-evolutionary transition from sea to land.
The relationship between acute thermal tolerance and habitat temperature in ectotherm animals informs about their thermal adaptation and is used to assess thermal safety margins and sensitivity to climate warming. We studied this relationship in an equatorial freshwater snail (Clea nigricans), belonging to a predominantly marine gastropod lineage (Neogastropoda, Buccinidae). We found that tolerance of heating and cooling exceeded average daily maximum and minimum temperatures, by roughly 20°C in each case. Because habitat temperature is generally assumed to be the main selective factor acting on the fundamental thermal niche, the discordance between thermal tolerance and environmental temperature implies trait conservation following 'in situ' environmental change, or following novel colonisation of a thermally less-variable habitat. Whereas heat tolerance could relate to an historical association with the thermally variable and extreme marine intertidal fringe zone, cold tolerance could associate with either an ancestral life at higher latitudes, or represent adaptation to cooler, higher-altitudinal, tropical lotic systems. The broad upper thermal safety margin (difference between heat tolerance and maximum environmental temperature) observed in this snail is grossly incompatible with the very narrow safety margins typically found in most terrestrial tropical ectotherms (insects and lizards), and hence with the emerging prediction that tropical ectotherms, are especially vulnerable to environmental warming. A more comprehensive understanding of climatic vulnerability of animal ectotherms thus requires greater consideration of taxonomic diversity, ecological transition and evolutionary history.
Sexual dimorphism in the shell size and shape of land snails has been less explored compared to that of other marine and freshwater snail taxa. This study examined the differences in shell size and shape across both sexes of Leptopoma perlucidum land snails. We collected 84 land snails of both sexes from two isolated populations on two islands off Borneo. A total of five shell size variables were measured: (1) shell height, (2) shell width, (3) shell spire height, (4) aperture height, and (5) aperture width. We performed frequentist and Bayesian t-tests to determine if there was a significant difference between the two sexes of L. perlucidum on each of the five shell measurements. Additionally, the shell shape was quantified based on nine landmark points using the geometric morphometric approach. We used generalised Procrustes and principal component analyses to test the effects of sex and location on shell shape. The results showed that female shells were larger than male shells across all five measurements (all with p-values < 0.05), but particularly in regards to shell height and shell width. Future taxonomic studies looking to resolve the Leptopoma species' status should consider the variability of shell size caused by sexual dimorphism.
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.
Metals are micropollutants that cannot be degraded by microorganisms and are infiltrated into various environmental media, including both freshwater and marine water. Metals from polluted water are absorbed by many aquatic species, especially fish. Fish is a staple food in the diets of many regions in the world; hence, both the type and concentration of metals accumulated and transferred from contaminated water sources to fish must be determined and assessed. In this study, the heavy metal concentration was determined and assessed in fish collected from freshwater sources via published literature and Estimated Daily Intake (EDI), Target hazard quotient (THQ), and Carcinogenic Risk (CR) analyses, aiming to examine the metal pollution in freshwater fish. The fish was used as a bioindicator, and Geographic information system (GIS) was sued to map the polluted regions. The results confirmed that Pb was detected in fish sampled at 28 locations, Cr at 24 locations, Cu and Zn at 30 locations, with values Pb detected ranging from 0.0016 mg kg-1 to 44.3 mg kg-1, Cr detected ranging from 0.07 mg kg-1 to 27 mg kg-1, Cu detected ranging from 0.031 mg kg-1 to 35.54 mg kg-1, and Zn detected ranging from 0.242 mg kg-1 to 103.2 mg kg-1. The strongest positive associations were discovered between Cu-Zn (r = 0.74, p
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.
The U.S. National Science Foundation-funded (DEB 1022720) 'All Cypriniformes Species Inventory' was initiated in 2010 and will be completed in 2015. It has accelerated the rate of discovery and description of cypriniform fishes, expanded our knowledge of the phylogenetic relationships of cypriniforms, increased the capacity for systematic research in other countries through student training and establishing long-term collaborations, including conferences in Thailand in 2012, Brunei in 2013, Burundi in 2013, and Malaysia in 2014, led to the formation of the Asian Society of Ichthyologists, and made available large numbers of specimens and tissues of freshwater fishes, including many species never before collected, in permanent collections in foreign and U.S. institutions.
Strains 2B12T, FVG1-MFV-O17 and FVG10-MFV-A16 were isolated from fresh water samples collected in Asia and Europe. The nucleotide sequences of the gapA barcodes revealed that all three strains belonged to the same cluster within the genus Dickeya. Using 13 housekeeping genes (fusA, rpoD, rpoS, glyA, purA, groEL, gapA, rplB, leuS, recA, gyrB, infB and secY), multilocus sequence analysis confirmed the existence of a new clade. When the genome sequences of these three isolates and other Dickeya species were compared, the in silico DNA-DNA hybridization and average nucleotide identity values were found to be no more than 45.50 and 91.22 %, respectively. The closest relative species was Dickeya fangzhongdai. Genome comparisons also highlighted genetic traits differentiating the new strains from D. fangzhongdai strains DSM 101947T (=CFBP 8607T) and B16. Phenotypical tests were performed to distinguish the three strains from D. fangzhongdai and other Dickeya species. The name Dickeya undicola sp. nov. is proposed with strain 2B12T (=CFBP 8650T=LMG 30903T) as the type strain.
Toxicity Identification Evaluation (TIE) is a useful method for the classification and identification of toxicants in a composite environment water sample. However, its extension to a larger sample size has been restrained owing to the limited throughput of toxicity bioassays. Here we reported the development of a high-throughput method of TIE Phase I. This newly developed method was assisted by the fluorescence-based cellular oxidation (CO) biosensor fabricated with roGFP2-expressing bacterial cells in 96-well microplate format. The assessment of four river water samples from Langat river basin by this new method demonstrated that the contaminant composition of the four samples can be classified into two distinct groups. The entire toxicity assay consisted of 2338 tests was completed within 12 h with a fluorescence microplate reader. Concurrently, the sample volume for each assay was reduced to 50 μL, which is 600 to 4700 times lesser to compare with conventional bioassays. These imply that the throughput of the CO biosensor-assisted TIE Phase I is now feasible for constructing a large-scale toxicity monitoring system, which would cover a whole watershed scale.
Despite the amount of awareness created, waterborne disease still poses threat, especially in developing countries. Due to the scarcity of reported data on waterborne parasites, the consumption of unsafe water prolongs. Thus, the occurrences of waterborne parasites from various samples were investigated from one of the Southeast Asian country, the Philippines.
The objective of this study was to assess the physico-chemical parameters and waterborne parasites in selected recreational lakes from Malaysia. Samples were collected from seven stations of Recreational Lake A (RL-A) and six stations of Recreational Lake B (RL-B). The samples were processed to detect the presence of Giardia spp. and Cryptosporidium spp. using immunomagnetic separation kit, helminth eggs or ova by bright field microscopy and Acanthamoeba spp. by cultivation in non-nutrient agar. Chemical parameters such as ammonia, chlorine, fluoride, nitrate and nitrite and physical parameters such as dissolved oxygen, electrical conductivity, pH, salinity, temperature and total dissolved solid were also measured. Both lakes were freshwater with salinity ranging from 0.05 to 0.09 ppt. Most stations of these lakes were contaminated with Cryptosporidium spp., Giardia spp., Ascaris spp. and hookworm. Schistosoma spp. was found in RL-B only, while Acanthamoeba spp. was found in all stations. Of all sampling sites, station 5 of RL-B is the most contaminated. Linear regression and correlation analysis revealed that Giardia spp. and Schistosoma spp. showed a significant negative correlation with turbidity (p water quality monitoring and to take appropriate safety measures to ensure maintenance of good water standards.
An ideal model organism for neurotoxicology research should meet several characteristics, such as low cost and amenable for high throughput testing. Javanese medaka (JM) has been widely used in the ecotoxicological studies related to the marine and freshwater environment, but rarely utilized for biomedical research. Therefore, in this study, the applicability of using JM in the neurotoxicology research was assessed using biochemical comparison with an established model organism, the zebrafish. Identification of biochemical changes due to the neurotoxic effects of ethanol and endosulfan was assessed using Fourier Transform Infrared (FTIR) analysis. Treatment with ethanol affected the level of lipids, proteins, glycogens and nucleic acids in the brain of JM. Meanwhile, treatment with endosulfan showed alteration in the level of lipids and nucleic acids. For the zebrafish, exposure to ethanol affected the level of protein, fatty acid and amino acid, and exposure to endosulfan induced alteration in the fatty acids, amino acids, nucleic acids and protein in the brain of zebrafish. The sensitive response of the JM toward chemicals exposure proved that it was a valuable model for neurotoxicology research. More studies need to be conducted to further develop JM as an ideal model organism for neurotoxicology research.
Freshwater fishes are species that spend their entire live in either freshwater inland or brackish estuaries. The checklist of the fish species should be updated consistently to ensure their diversity is preserved. The study of diversity and distribution of freshwater fishes at Sungai Muar, Kuala Pilah, Negeri Sembilan was carried out on 14 and 15 March 2020 to identify the fish diversity and their development in Sg. Muar, Negeri Sembilan. Trawl (fish collections), weighing machine and ruler (morphometric observations) was used during experiment. Fish species found during this study include Oreochromis mossambicus (Family Cichlidae), Hemibagrus nemurus (Family Bagridae), Homaloptera tweediei (Family Balitoridae), Notopterus notopterus (Family Notopteridae), Oxyeleotris marmorata (family Eleotridae), and five species of Family Cyprinidae, which were Mystacoleucus marginatus, Osteochilus haseltii, Cyclocheilichthys apogon, Barbonymus schwanenfeldii and Hampala microlepidota. Fishes from family Cyprinidae was dominated the area with a total of 102 individuals found. The statistical analysis shows the diversity (H’)=1.826, richness (R’)=2.004 and evenness (E’)= 0.5645 of freshwater fish at Sungai Muar, respectively. The most dominant species found was Mystacoleucus marginatus with 50 individuals and the least abundant species were Barbonymus schwanenfeldii, Homaloptera tweediei and Oxyeleotris marmorata with one individual only. The length-weight regression shows a positive allometric growth with ‘b’ value is higher than 3 at both stations; 3.0118 (Station 1) and 3.4409 (Station 2). It shows that the fish becomes heavier as its length increases. This data provides information about the fish habitat in Sungai Muar and can be used to update the checklist of fish species in Sg Muar. The data obtained provides information about the fish habitat in Sungai Muar which could be useful for the planning of fishing activities Other than that, it also important as a guideline for future research and conservation purposes especially in Negeri Sembilan.
Betta rubra is an ornamental freshwater fish endemic to northern Sumatra, Indonesia. The B. rubra population has decreased in recent decades, and is classified as an endangered species in the IUCN Red List. This study aims to report for the first time infection by L. cyprinacea in B. rubra harvested from the Aceh Besar region of Indonesia. The fish samples were obtained from the Cot Bira tributaries, Aceh Besar District, Indonesia from January to December 2020. The results showed that the parasite infected 6 out of 499 samples in August and September, with a prevalence and intensity rate of 1% and 2 parasites/fish, respectively. The eyes and pectoral fins were the common infection sites. Despite B. rubra is not an optimal host (small size) for the parasite, this parasite might serve as additional threatening factors for the endangered B. rubra fish population.
A comparative study on the fatty acids contents of three Malaysian marine fishes Tenualosa toli (Terubok), Rastrelliger kanagurta (Kembong), Stolephorus baganensis (Bilis) and three freshwater fishes Channa striatus (Haruan), Pangasius hypothalamus (Patin), Clarias macrocephalus (Keli) were carried out. Marine fishes showed more unsaturated fatty acids with 3, 4, 5 and 6 double bonds than in freshwater fishes. Two n-3 polyunsaturated fatty acids (PUFAs); eicosapentaenoic acid (EPA) and docasahaexaenoic acid (DHA) were found more in marine fishes PUFAs than in freshwater fishes. Based on the fatty acids content of DHA, EPA and arachidonic acid (AA), Stolephorus baganensis provides the best source of it (4.68%,10.5%, 4.68%) followed by Rastrelliger kanagurta (10.62%, 4.85%, 3.17%) and Tenualosa toli (9.93%, 2.50%, 0.16%). However, freshwater fishes showed small range of DHA (0.63% - 1.41%), EPA (0.11% - 0.25%) and AA (1.41% - 4.46%). Saturated fatty acids palmitic was the major fatty acid found in all fishes studied.