Displaying publications 121 - 140 of 144 in total

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  1. Fulltext Polyhydroxyalkanoate biosynthesis and simplified polymer recovery by a novel moderately halophilic bacterium isolated from hypersaline microbial mats
    Rathi DN, Amir HG, Abed RM, Kosugi A, Arai T, Sulaiman O, et al.
    J Appl Microbiol, 2013 Feb;114(2):384-95.
    PMID: 23176757 DOI: 10.1111/jam.12083
    Halophilic micro-organisms have received much interest because of their potential biotechnological applications, among which is the capability of some strains to synthesize polyhydroxyalkanoates (PHA). Halomonas sp. SK5, which was isolated from hypersaline microbial mats, accumulated intracellular granules of poly(3-hydroxybutyrate) [P(3HB)] in modified accumulation medium supplemented with 10% (w/v) salinity and 3% (w/v) glucose.
    Matched MeSH terms: Salinity
  2. Fulltext Characterization of salt-tolerant plant growth-promoting rhizobacteria and the effect on growth and yield of saline-affected rice
    Shultana R, Kee Zuan AT, Yusop MR, Saud HM
    PLoS One, 2020;15(9):e0238537.
    PMID: 32886707 DOI: 10.1371/journal.pone.0238537
    In this study, we characterized, identified, and determined the effect of salt-tolerant PGPR isolated from coastal saline areas on rice growth and yield. A total of 44 bacterial strains were isolated, and 5 were found to be tolerant at high salt concentration. These isolates were further characterized for salinity tolerance and beneficial traits through a series of quantitative tests. Biochemical characterization showed that bacterial survivability decreases gradually with the increase of salt concentration. One of the strains, UPMRB9, produced the highest amount of exopolysaccharides when exposed to 1.5M of NaCl. Moreover, UPMRB9 absorbed the highest amount of sodium from the 1.5M of NaCl-amended media. The highest floc yield and biofilm were produced by UPMRE6 and UPMRB9 respectively, at 1M of NaCl concentration. The SEM observation confirmed the EPS production of UPMRB9 and UPMRE6 at 1.5M of NaCl concentration. These two isolates were identified as Bacillus tequilensis and Bacillus aryabhattai based on the 16S rRNA gene sequence. The functional group characterization of EPS showed the presence of hydroxyl, carboxyl, and amino groups. This corresponded to the presence of carbohydrates and proteins in the EPS and glucose was identified as the major type of carbohydrate. The functional groups of EPS can help to bind and chelate Na+ in the soil and thereby reduces the plant's exposure to the ion under saline conditions. The plant inoculation study revealed significant beneficial effects of bacterial inoculation on photosynthesis, transpiration, and stomatal conductance of the plant which leads to a higher yield. The Bacillus tequilensis and Bacillus aryabhattai strains showed good potential as PGPR for salinity mitigation practice for coastal rice cultivation.
    Matched MeSH terms: Salinity
  3. Sorption of ionized dyes on high-salinity microalgal residue derived biochar: Electron acceptor-donor and metal-organic bridging mechanisms
    Tan X, Zhu S, Show PL, Qi H, Ho SH
    J Hazard Mater, 2020 07 05;393:122435.
    PMID: 32151933 DOI: 10.1016/j.jhazmat.2020.122435
    Biochar (BC) has attracted much attention owing to its superior sorption capacity towards ionized organic contaminants. However, the mechanism of ionized organics sorption occurring within BC containing large amounts of minerals is still controversial. In this study, we demonstrate the physicochemical structure of high-salinity microalgal residue derived biochar (HSBC) and elucidate the corresponding sorption mechanisms for four ionized dyes along with determining the crucial role of involved minerals. The results indicate that sodium and calcium minerals mainly exist within HSBCs, and the pyrolysis temperature can dramatically regulate the phases and interfacial property of both carbon matrix and minerals. As a result, the HSBC shows a higher sorption potential, benefiting from abundant functional groups and high content of inorganic minerals. Using theoretical calculations, the activities of electron donor-acceptor interaction between HSBCs and different dyes are clearly illustrated, thereby identifying the critical role of Ca2+ in enhancing the removal of ionized dyes in HSBCs. In addition, Ca-containing minerals facilitate the sorption of ionized dyes in HSBCs by forming ternary complexes through metal-bridging mechanism. These results of mineral-induced dye sorption mechanisms help to better understand the sorption of ionized organics in high-salt containing BC and provide a new disposal strategy for hazardous microalgal residue, as well as provide a breakthrough in making the remediation of ionized organic contaminated microalgal residue derived absorbent feasible.
    Matched MeSH terms: Salinity
  4. Environmental effects on the oxygen consumption rate in juvenile Epinephelus fuscoguttatus (Forsskal, 1775)
    Okomoda VT, Mithun S, Chatterji A, Effendy MAW, Oladimeji AS, Abol-Munafi AB, et al.
    Fish Physiol Biochem, 2020 Aug;46(4):1497-1505.
    PMID: 32378001 DOI: 10.1007/s10695-020-00807-7
    This study was designed to optimize the culture conditions of juvenile Epinephelus fuscoguttatus (Forsskål, 1775) under laboratory conditions. To this effect, the rate of oxygen consumption was monitored as an index of stress under different temperature, salinity, pH, photoperiod, and urea concentrations. The result obtained after 12 h of exposure suggests the preference of the juvenile E. fuscoguttatus to a temperature range of 15-25 °C and salinity of 30 ppt. Based on this study, temperature was found to be the most lethal as 100% mortality was observed after 6 h in fish exposure to temperatures above the optimal (≥ 30 °C). However, the oxygen consumption rate was similar under the different pH, photoperiod, and urea concentration tested. It was concluded that water temperature was most critical in terms of respiration physiology of the juvenile E. fuscoguttatus given the range and levels of environmental factors tested in this study.
    Matched MeSH terms: Salinity
  5. Fulltext EFFECTS OF EXOGENOUS ARACHIDONIC ACID ON MORPHOLOGICAL TRAITS AND FATTY ACID PROFILE OFRICE (Oryza sativaL.) GROWN ON SALINE SOIL
    PUTERI AFIQAH ABDUL WAHAB, AZIZ AHMAD
    UMT Journal of Undergraduate Research, 2019;1(3):68-78.
    MyJurnal
    Salinity is one of the major constraintsin the rice production worldwide. Rice plants have moderate tolerance towardssalinity. Salinitychangescell membrane permeability and fatty acid compositionsby releasing the free fatty acids. Nonetheless, the effect of exogenous fatty acid such as arachidonic acid (AA) on rice grown on saline soil is yetunknown. Theobjective of the current study isto determine the effectofAA onthe morphological traits and freefatty acidsofrice plantgrown under saline conditions.Rice plants grown on saline soil (EC=12 ds/m)were treated with 50 μMAAon day 45 after transplant. Leaves and panicleswere sampledafter two weeks of treatment and analysed for fatty acid profile using GC-MS. Themorphological traits were observedat the maturity stage. Results showed that AA treatment improved the grain fill-in of the saline stress riceand reduced the accumulation of free fatty acids in the cell. The AAtreatment also increased the linoleic acid (18:2), linolenic acid (18:3) in paniclesand, dihomo-γ-linolenic acid(20:3) and nervonic acid (24:1) in leaves. The finding suggests that exogenous AAregulates salinity stress in rice by reducing the accumulation offree fatty acids.
    Matched MeSH terms: Salinity
  6. Genome Mining Reveals the Biosynthetic Pathways of Polyhydroxyalkanoate and Ectoines of the Halophilic Strain Salinivibrio proteolyticus M318 Isolated from Fermented Shrimp Paste
    Van Thuoc D, Loan TT, Trung TA, Van Quyen N, Tung QN, Tien PQ, et al.
    Mar Biotechnol (NY), 2020 Oct;22(5):651-660.
    PMID: 32827070 DOI: 10.1007/s10126-020-09986-z
    Salinivibrio proteolyticus M318, a halophilic bacterium isolated from fermented shrimp paste, is able to produce polyhydroxyalkanoate (PHA) from different carbon sources. In this study, we report the whole-genome sequence of strain M138, which comprises 2 separated chromosomes and 2 plasmids, and the complete genome contains 3,605,935 bp with an average GC content of 49.9%. The genome of strain M318 contains 3341 genes, 98 tRNA genes, and 28 rRNA genes. The 16S rRNA gene sequence and average nucleotide identity analysis associated with morphological and biochemical tests showed that this strain has high homology to the reference strain Salinivibrio proteolyticus DSM 8285. The genes encoding key enzymes for PHA and ectoine synthesis were identified from the bacterial genome. In addition, the TeaABC transporter responsible for ectoine uptake from the environment and the operon doeABXCD responsible for the degradation of ectoine were also detected. Strain M318 was able to produce poly(3-hydroxybutyrate) [P(3HB)] from different carbon sources such as glycerol, maltose, glucose, fructose, and starch. The ability to produce ectoines at different NaCl concentrations was investigated. High ectoine content of 26.2% of cell dry weight was obtained by this strain at 18% NaCl. This report provides genetic information regarding adaptive mechanisms of strain M318 to stress conditions, as well as new knowledge to facilitate the application of this strain as a bacterial cell factory for the production of PHA and ectoine.
    Matched MeSH terms: Salinity
  7. Geo-accumulation index and contamination factors of heavy metals (Zn and Pb) in urban river sediment
    Haris H, Looi LJ, Aris AZ, Mokhtar NF, Ayob NAA, Yusoff FM, et al.
    Environ Geochem Health, 2017 Dec;39(6):1259-1271.
    PMID: 28484873 DOI: 10.1007/s10653-017-9971-0
    The aim of the present study was to appraise the levels of heavy metal contamination (Zn and Pb) in sediment of the Langat River (Selangor, Malaysia). Samples were collected randomly from 15 sampling stations located along the Langat River. The parameters measured were pH, redox potential, salinity, electrical conductivity, loss of ignition, cation exchanges capacity (Na, Mg, Ca, K), and metal ions (Zn and Pb). The geo-accumulation index (I geo) and contamination factor (C f) were applied to determine and classify the magnitude of heavy metal pollution in this urban river sediment. Results revealed that the I geo of Pb indicated unpolluted to moderately polluted sediment at most of the sampling stations, whereas Zn was considered to be within background concentration. The I geo results were refined by the C f values, which showed Pb with very high C f at 12 stations. Zinc, on the other hand, had low to moderate C f values. These findings indicated that the sediment of the Langat River is severely polluted with Pb. The Zn concentration at most sampling points was well below most sediment quality guidelines. However, 40% of the sampling points were found to have a Pb concentration higher than the consensus-based probable effect concentration of 128 mg/kg (concentrations above this value are likely to cause harmful effects). This result not only highlights the severity of Pb pollution in the sediment of the Langat River, but also the potential risk it poses to the environment.
    Matched MeSH terms: Salinity
  8. Fulltext Food security : the needs for international treaty on plant genetic resources to ensure smoother flow of genes
    Mohd Shukor, N.
    Buletin Persatuan Genetik Malaysia, 2010;16(1):15-17.
    MyJurnal
    Never in the history of modern Malaysia, the general population at all levels are being threatened by food security. Food becoming less available and more expensive. Many factors, both long- and short-term, have contributed to the shortage. At a global level, available data seems to indicate that we have been consuming more than what we produce. Then came the shortfall in global rice production caused by the impact of climate change such as the widespread drought in India and China in 2002, typhoons in the Philippines in 2006, and the major flooding in Bangladesh in 2007. This was followed by the returns of pests such as planthoppers, and the various virus diseases transmitted particularly at regions with growing seasons having abnormally higher temperatures caused by climate change. Since the crisis started, scientists particularly breeders all over the world were requested to strengthen and upgrade the breeding program and facilities for the development of new varieties with increased tolerance to drought, flooding, and salinity as well resistant to insects and diseases. An important pre-requisite for such activities is the free flow of plant genetic resources for food and agriculture (pgrfa). The adoption of the Convention on Biological Diversity (CBD) has drastically slowed down the movement of many plant genetic resources and this has threatened the future supply of food. The International Treaty on Plant Genetic Resource for Food and Agriculture (ITPGRFA or the Treaty) is a global reaction to the rising tide of measures taken by many governments as a result CBD to extend their sovereign control over genetic resources. Many countries felt that those measures are inappropriate for food and agricultural crop genetic resources. The Treaty on the other hand recognizes that access and benefit sharing for agricultural biodiversity must be treated differently from the way it is generally treated under CBD. This paper discusses some of the key points and provisions from the treaty and some issues arising from its negotiation and future implementation in Malaysia.
    Matched MeSH terms: Salinity
  9. Fulltext Determination of major ions concentrations in kelantan well water using edxrf
    Zaini Hamzah, Wan Noorhayani Wan Rosdi, Abdul Khalik Wood
    Journal of Nuclear and Related Technologies, 2012;2012(2):66-72.
    MyJurnal
    Well water is a renewable natural resources and one of the drinking water sources. The well water may constituted of dissolved essential chemicals such as K+, Ca''+ and Na+ ; and natural radionuclides such as radioisotopes from uranium-thorium decay series. The geology and mineral composition of the soil will determined the kinds and levels of chemical contents in the groundwater resources. The water flows through the geological formation and dissolved the chemicals before reaching the aquifers. To evaluate how much chemicals and natural radioactive in the water resources, a study has been carried out. Well water samples in this study were taken from 3 districts in Kelantan, which is Bachok, Machang and Kuala Krai. Similarly, in situ water quality parameters were measured using YSI portable water quality parameter include pH, salinity, dissolve oxygen(DO), conductivity, turbidity and total dissolved solids(TDS). The concentrations of K', Ca" and Na' were determined using Energy Dispersive X-ray Fluorescence (EDXRF). Five ml of filtered sample was pipette into the sample cup and, irradiated and measured for 100 seconds counting times. The type of filter used for measuring If+ and Cat{ was Al-thin and default for Nat The ranged of concentration of Kt Ce and Na+ is 23.04-251.89, 3.12-.45.41, and 3.71-125.75 ppm, respectively.
    Matched MeSH terms: Salinity
  10. Distributions of particulate and dissolved phosphorus in aquatic habitats of Peninsular Malaysia
    Lim JH, Lee CW, Bong CW, Affendi YA, Hii YS, Kudo I
    Mar Pollut Bull, 2018 Mar;128:415-427.
    PMID: 29571392 DOI: 10.1016/j.marpolbul.2018.01.037
    Particulate phosphorus was the dominant phosphorus species and accounted for 72 ± 5% of total phosphorus in coastal habitats, 63 ± 4% in estuaries, 58 ± 6% in lakes and 80 ± 7% in aquaculture farms whereas dissolved inorganic phosphorus (DIP) and dissolved organic phosphorus (DOP) were minor components. Correlation analyses (DIP vs Chl a; R2 = 0.407, df = 31, p 
    Matched MeSH terms: Salinity
  11. Fulltext Sulfated galactans from red seaweeds and their potential applications
    Lim, Yi-Yi, Lee, Wei-Kang, Leow, Adam Thean-Chor, Parameswari Namasivayam, Janna-Ong Abdullah, Ho, Chai-Ling
    The Pertanika Journal of Scholarly Research Reviews, 2018;4(2):1-17.
    MyJurnal
    Red seaweeds (Rhodophyta) produce a variety of sulfated galactans in their cell wall matrix and intercellular space, contributing up to 50-60 % of their total dry weight. These sulfated polysaccharides are made up of galactose disaccharides substituted with sulfate, methoxyl, pyruvic acid, or non-galactose monosaccharides (e.g. xylose, glucose and mannose). They are required by the Rhodophytes for protection against pathogen, desiccation, tidal waves and extreme changes in pH, temperature and salinity. Since ancient times, sulfated galactans from red seaweeds, such as agar and carrageenan, have been consumed as human foods and later being used in traditional medicine. Nowadays, some red seaweeds are cultivated and exploited for commercial uses in various fields. In this review, different types of sulfated galactans found in red seaweeds and their current and potential uses in food, biotechnology, medical and pharmaceutical industries are discussed.
    Matched MeSH terms: Salinity
  12. Risk factors associated with viral nervous necrosis in hybrid groupers in Malaysia and the high similarity of its causative agent nervous necrosis virus to reassortant red-spotted grouper nervous necrosis virus/striped jack nervous necrosis virus strains
    Ariff N, Abdullah A, Azmai MNA, Musa N, Zainathan SC
    Vet World, 2019 Aug;12(8):1273-1284.
    PMID: 31641308 DOI: 10.14202/vetworld.2019.1273-1284
    Background and Aim: Viral nervous necrosis (VNN) is a serious disease of several marine fish species. VNN causes 100% mortality in the larval stages, while lower losses have been reported in juvenile and adult fish. This study aimed to detect the occurrence of VNN while identifying its associated risk factors and the genotypes of its causative agent in a hybrid grouper hatchery in Malaysia.

    Materials and Methods: A batch of newly hatched hybrid grouper fry (Epinephelus fuscoguttatus × Epinephelus lanceolatus) were followed from the larval stage to market size. Samples of the hybrid groupers, water, live feed, and artificial fish pellets were collected periodically from day 0 to 180 in the hybrid grouper hatchery. Reverse transcription-polymerase chain reaction (RT-PCR) and nested PCR amplifications were carried out on VNN-related sequences. The phylogenetic tree including the sampled causative agent of VNN was inferred from the coat protein genes from all known Betanodavirus species using Molecular Evolutionary Genetics Analysis (MEGA). Pearson's correlation coefficient values were calculated to determine the strength of the correlation between the presence of VNN in hybrid grouper samples and its associated risk factors.

    Results: A total of 113 out of 146 pooled and individual samples, including hybrid grouper, water, and artificial fish pellet samples, demonstrated positive results in tests for the presence of VNN-associated viruses. The clinical signs of infection observed in the samples included darkened skin, deformation of the backbone, abdominal distension, skin lesions, and fin erosion. VNN was present throughout the life stages of the hybrid groupers, with the first detection occurring at day 10. VNN-associated risk factors included water temperature, dissolved oxygen content, salinity, ammonia level, fish size (adults more at risk than younger stages), and life stage (age). Detection of VNN-associated viruses in water samples demonstrated evidence of horizontal transmission of the disease. All the nucleotide sequences found in this study had high nucleotide identities of 88% to 100% to each other, striped jack nervous necrosis virus (SJNNV), and the reassortant strain red-spotted grouper NNV/SJNNV (RGNNV/SJNNV) isolate 430.2004 (GenBank accession number JN189932.1) (n=26). The phylogenetic analysis showed that quasispecies was present in each VNN-causing virus-positive sample, which differed based on the type of sample and life stage.

    Conclusion: This study was the first to confirm the existence of a reassortant strain (RGNNV/SJNNV) in hybrid groupers from Malaysia and Southeast Asia. However, the association between the mode of transmission and the risk factors of this virus needs to be investigated further to understand the evolution and potential new host species of the reassortant strain.

    Matched MeSH terms: Salinity
  13. Ultrasound-assisted weak-acid hydrolysis of crystalline starch nanoparticles for chemical enhanced oil recovery
    Agi A, Junin R, Arsad A, Abbas A, Gbadamosi A, Azli NB, et al.
    Int J Biol Macromol, 2020 Apr 01;148:1251-1271.
    PMID: 31760018 DOI: 10.1016/j.ijbiomac.2019.10.099
    Ascorbic acid was used for the first time to synthesize crystalline starch nanoparticles (CSNP). The physical properties of the CSNP were investigated. Rheological properties of the crystalline starch nanofluid (CSNF) were compared with native cassava starch (CS) and commercial polymer xanthan. Interfacial properties of the CSNF at the interface of oil and water (O/W) were investigated at different concentrations and temperatures. Wettability alteration efficiency of CSNF on oil-wet sandstone surface was investigated using the sessile drop method. Core flooding experiment was conducted at reservoir conditions. The methods were effective in producing spherical and polygonal nanoparticles with a mean diameter of 100 nm and increased in crystallinity of 7%. Viscosity increased with increase in surface area and temperature of the CSNF compared to a decrease in viscosity as the temperature increases for xanthan. Interfacial tension (IFT) decreased with increase in concentration of CSNF, electrolyte and temperature. The results show that CSNF can change the wettability of sandstone at low concentration, high salinity and elevated temperature. Pressure drops data shows stability of CSNF at 120 °C. The formation of oil bank was enough to increase oil recovery by 23%.
    Matched MeSH terms: Salinity
  14. Comparative effects of different soil conditioners on wheat growth and yield grown in saline-sodic soils
    Zia-ur-Rehman M, Sabir M, Shahjahan, Ahmed HR, Muhammad Rizwan, Ali S
    Sains Malaysiana, 2016;45:339-346.
    Among abiotic stresses, salinity is the main abiotic stress limiting crop growth and yield worldwide. Improving agri-food production in salt-prone areas is the key to meet the increasing food demands in near future. A greenhouse experiment was conducted to investigate the effect of different soil conditioners, gypsum (GYP), citric acid (CA), ethylene diamine tetraacetic acid (EDTA) and polyvinyl alcohol (PVA), on growth and yield of wheat (Triticum aestivum L.) grown in salinesodic soil. Gypsum was applied at a rate of 100% soil gypsum requirement while other amendments were applied each at a rate of 5 g kg-1 of soil. The results showed that EDTA treatment increased pH and electrical conductivity (ECe) of soil while pH significantly decreased when treated with citric acid. Soil sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP) decreased in all treatments following the order: CT > PVA > EDTA > CA > GYP. Addition of CA positively affected growth parameters as compared to other soil conditioners including plant height, number of tillers per plant, number of spikes per plant, plant dry weight and grain yield while EDTA negatively affected these parameters. Addition of CA also significantly increased photosynthetic rate, stomatal conductance, transpiration rate and chlorophyll contents while EDTA decreased these parameters. We conclude that increase in plant growth and yield with CA might be due to the effect of CA on soil properties which positively affected plant physiological parameters.
    Matched MeSH terms: Salinity
  15. Water quality status of selected rivers in Kota Marudu, Sabah, Malaysia and its suitability for usage
    Ahmad Zaharin Aris, Wan YL, Sarva MP, Mohd Kamil Yusoff, Muhamma Firuz Ramli, Hafizan Juahir
    Sains Malaysiana, 2014;43:377-388.
    The water chemistry of selected rivers in Kota Marudu, Sabah was studied based on the major ion chemistry and its suitability for drinking and irrigation purposes. Ten sampling stations were selected and water samples were collected from each station to assess its chemical properties. The physico-chemical variables including temperature, electrical conductivity (EC), total dissolved solids (TDS), salinity, dissolved oxygen (DO), pH, turbidity, ammoniacal-nitrogen (NH3-N), biological oxygen demand (BOD), chemical oxygen demand (COD) and total suspended solid (TSS) were measured. The cations (K, Mg, Ca, Na) were analyzed by ICP-MS. Most of the variables were within the drinking water quality standards stipulated by the World Health Organization (WHO) and the Ministry of Health (MOH), Malaysia except for turbidity. Sodium adsorption ratio (SAR) and salinity hazard were calculated to identify the suitability of the water as irrigation water. The Wilcox diagram classifies that only 10% of samples are not suitable for the purpose of irrigation. The overall results showed that most of the rivers in Kota Marudu are still in a clean condition and suitable for drinking and irrigation purposes except for Sumbilingan River, which is considered as slightly polluted. The results are supported by the hierarchical cluster analysis as the stations were grouped into two groups; low and high pollution intensities. This preliminary result can update the baseline data of selected water quality parameters in the Kota Marudu and could serve as tool for assisting relevant government bodies in regulating the water resources policies in the future.
    Matched MeSH terms: Salinity
  16. Variations in the migratory history of the tropical catadromous eels Anguilla bicolor bicolor and A. bicolor pacifica in south-east Asian waters
    Arai T, Chino N
    J Fish Biol, 2019 May;94(5):752-758.
    PMID: 30847927 DOI: 10.1111/jfb.13952
    Fish movements between aquatic habitats of different salinity ranges (fresh, estuarine, marine) by the tropical catadromous eels Anguilla bicolor bicolor and A. bicolor pacifica were examined by analysing the otolith strontium and calcium concentrations of yellow (immature) and silver (mature) stage eels collected in south-east Asian (Indonesia, Malaysia and Vietnam) waters. The ratios suggest that all migratory-type eels, including freshwater, brackish water and marine residents, pass the river mouth. However, the habitat preference was different among the sites (countries). In Indonesia and Vietnam, most A. bicolor bicolor and A. bicolor pacifica were either marine or brackish water residents in this study. Alternatively, most A. bicolor bicolor were freshwater residents in Malaysia; such a typical catadromous migration pattern in these eels has not been found in previous studies. The wide range of otolith Sr:Ca in both subspecies indicates that the habitat use of these tropical eels was opportunistic among fresh, brackish and marine waters during their growth phases following recruitment to coastal areas. The geographical variability of migratory histories suggests that habitat use might be determined by the inter and intraspecific competition and environmental conditions at each site.
    Matched MeSH terms: Salinity
  17. Effects of acute salt stress on modulation of gene expression in a Malaysian salt-tolerant indigenous rice variety, Bajong
    Yeo BPH, Bhave M, Hwang SS
    J Plant Res, 2018 Jan;131(1):191-202.
    PMID: 28921169 DOI: 10.1007/s10265-017-0977-6
    The small genome size of rice relative to wheat and barley, together with its salt sensitivity, make it an ideal candidate for studies of salt stress response. Transcriptomics has emerged as a powerful technique to study salinity responses in many crop species. By identifying a large number of differentially expressed genes (DEGs) simultaneously after the stress induction, it can provide crucial insight into the immediate responses towards the stressor. In this study, a Malaysian salt-tolerant indigenous rice variety named Bajong and one commercial rice variety named MR219 were investigated for their performance in plant growth and ion accumulation properties after salt stress treatment. Bajong was further investigated for the changes in leaf's transcriptome after 6 h of stress treatment using 100 mM NaCl. Based on the results obtained, Bajong is found to be significantly more salt tolerant than MR219, showing better growth and a lower sodium ion accumulation after the stress treatment. Additionally, Bajong was analysed by transcriptomic sequencing, generating a total of 130 millions reads. The reads were assembled into de novo transcriptome and each transcript was annotated using several pre-existing databases. The transcriptomes of control and salt-stressed samples were then compared, leading to the discovery of 4096 DEGs. Based on the functional annotation results obtained, the enrichment factor of each functional group in DEGs was calculated in relation to the total reads obtained. It was found that the group with the highest gene modulation was involved in the secondary metabolite biosynthesis of plants, with approximately 2.5% increase in relation to the total reads obtained. This suggests an extensive transcriptional reprogramming of the secondary metabolic pathways after stress induction, which could be directly responsible for the salt tolerance capability of Bajong.
    Matched MeSH terms: Salinity
  18. An integrated assessment of seawater intrusion in a small tropical island using geophysical, geochemical, and geostatistical techniques
    Kura NU, Ramli MF, Ibrahim S, Sulaiman WN, Aris AZ
    Environ Sci Pollut Res Int, 2014;21(11):7047-64.
    PMID: 24532282 DOI: 10.1007/s11356-014-2598-0
    In this study, geophysics, geochemistry, and geostatistical techniques were integrated to assess seawater intrusion in Kapas Island due to its geological complexity and multiple contamination sources. Five resistivity profiles were measured using an electric resistivity technique. The results reveal very low resistivity <1 Ωm, suggesting either marine clay deposit or seawater intrusion or both along the majority of the resistivity images. As a result, geochemistry was further employed to verify the resistivity evidence. The Chadha and Stiff diagrams classify the island groundwater into Ca-HCO3, Ca-Na-HCO3, Na-HCO3, and Na-Cl water types, with Ca-HCO3 as the dominant. The Mg(2+)/Mg(2+)+Ca(2+), HCO3 (-)/anion, Cl(-)/HCO3 (-), Na(+)/Cl(-), and SO4 (2-)/Cl(-) ratios show that some sampling sites are affected by seawater intrusion; these sampling sites fall within the same areas that show low-resistivity values. The resulting ratios and resistivity values were then used in the geographical information system (GIS) environment to create the geostatistical map of individual indicators. These maps were then overlaid to create the final map showing seawater-affected areas. The final map successfully delineates the area that is actually undergoing seawater intrusion. The proposed technique is not area specific, and hence, it can work in any place with similar completed characteristics or under the influence of multiple contaminants so as to distinguish the area that is truly affected by any targeted pollutants from the rest. This information would provide managers and policy makers with the knowledge of the current situation and will serve as a guide and standard in water research for sustainable management plan.
    Matched MeSH terms: Salinity
  19. Fulltext Temporal variation of bacterial respiration and growth efficiency in tropical coastal waters
    Lee CW, Bong CW, Hii YS
    Appl Environ Microbiol, 2009 Dec;75(24):7594-601.
    PMID: 19820145 DOI: 10.1128/AEM.01227-09
    We investigated the temporal variation of bacterial production, respiration, and growth efficiency in the tropical coastal waters of Peninsular Malaysia. We selected five stations including two estuaries and three coastal water stations. The temperature was relatively stable (averaging around 29.5 degrees C), whereas salinity was more variable in the estuaries. We also measured dissolved organic carbon and nitrogen (DOC and DON, respectively) concentrations. DOC generally ranged from 100 to 900 microM, whereas DON ranged from 0 to 32 microM. Bacterial respiration ranged from 0.5 to 3.2 microM O2 h(-1), whereas bacterial production ranged from 0.05 to 0.51 microM C h(-1). Bacterial growth efficiency was calculated as bacterial production/(bacterial production + respiration), and ranged from 0.02 to 0.40. Multiple correlation analyses revealed that bacterial production was dependent upon primary production (r2 = 0.169, df = 31, and P < 0.02) whereas bacterial respiration was dependent upon both substrate quality (i.e., DOC/DON ratio) (r2 = 0.137, df = 32, and P = 0.03) and temperature (r2 = 0.113, df = 36, and P = 0.04). Substrate quality was the most important factor (r2 = 0.119, df = 33, and P = 0.04) for the regulation of bacterial growth efficiency. Using bacterial growth efficiency values, the average bacterial carbon demand calculated was from 5.30 to 11.28 microM C h(-1). When the bacterial carbon demand was compared with primary productivity, we found that net heterotrophy was established at only two stations. The ratio of bacterial carbon demand to net primary production correlated significantly with bacterial growth efficiency (r2 = 0.341, df = 35, and P < 0.001). From nonlinear regression analysis, we found that net heterotrophy was established when bacterial growth efficiency was <0.08. Our study showed the extent of net heterotrophy in these waters and illustrated the importance of heterotrophic microbial processes in coastal aquatic food webs.
    Matched MeSH terms: Salinity
  20. Fulltext Comparative transcriptome analysis of leaves and roots in response to sudden increase in salinity in Brassica napus by RNA-seq
    Yong HY, Zou Z, Kok EP, Kwan BH, Chow K, Nasu S, et al.
    Biomed Res Int, 2014;2014:467395.
    PMID: 25177691 DOI: 10.1155/2014/467395
    Amphidiploid species in the Brassicaceae family, such as Brassica napus, are more tolerant to environmental stress than their diploid ancestors.A relatively salt tolerant B. napus line, N119, identified in our previous study, was used. N119 maintained lower Na(+) content, and Na(+)/K(+) and Na(+)/Ca(2+) ratios in the leaves than a susceptible line. The transcriptome profiles of both the leaves and the roots 1 h and 12 h after stress were investigated. De novo assembly of individual transcriptome followed by sequence clustering yielded 161,537 nonredundant sequences. A total of 14,719 transcripts were differentially expressed in either organs at either time points. GO and KO enrichment analyses indicated that the same 49 GO terms and seven KO terms were, respectively, overrepresented in upregulated transcripts in both organs at 1 h after stress. Certain overrepresented GO term of genes upregulated at 1 h after stress in the leaves became overrepresented in genes downregulated at 12 h. A total of 582 transcription factors and 438 transporter genes were differentially regulated in both organs in response to salt shock. The transcriptome depicting gene network in the leaves and the roots regulated by salt shock provides valuable information on salt resistance genes for future application to crop improvement.
    Matched MeSH terms: Salinity
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