Browse publications by year: 2013

  1. Sansone G, Fong GT, Hall PA, Guignard R, Beck F, Mons U, et al.
    BMC Public Health, 2013;13:346.
    PMID: 23587205 DOI: 10.1186/1471-2458-13-346
    Prior studies have demonstrated that time perspective-the propensity to consider short-versus long-term consequences of one's actions-is a potentially important predictor of health-related behaviors, including smoking. However, most prior studies have been conducted within single high-income countries. The aim of this study was to examine whether time perspective was associated with the likelihood of being a smoker or non-smoker across five countries that vary in smoking behavior and strength of tobacco control policies.
    MeSH terms: Adolescent; Adult; Attitude to Health; China/epidemiology; Europe/epidemiology; Female; Health Surveys; Humans; Longitudinal Studies; Malaysia/epidemiology; Male; Middle Aged; Smoking/epidemiology*; Smoking/psychology*; Young Adult
  2. Shammugasamy B, Ramakrishnan Y, Ghazali HM, Muhammad K
    J Chromatogr A, 2013 Jul 26;1300:31-7.
    PMID: 23587317 DOI: 10.1016/j.chroma.2013.03.036
    A simple sample preparation technique coupled with reversed-phase high-performance liquid chromatography was developed for the determination of tocopherols and tocotrienols in cereals. The sample preparation procedure involved a small-scale hydrolysis of 0.5g cereal sample by saponification, followed by the extraction and concentration of tocopherols and tocotrienols from saponified extract using dispersive liquid-liquid microextraction (DLLME). Parameters affecting the DLLME performance were optimized to achieve the highest extraction efficiency and the performance of the developed DLLME method was evaluated. Good linearity was observed over the range assayed (0.031-4.0μg/mL) with regression coefficients greater than 0.9989 for all tocopherols and tocotrienols. Limits of detection and enrichment factors ranged from 0.01 to 0.11μg/mL and 50 to 73, respectively. Intra- and inter-day precision were lower than 8.9% and the recoveries were around 85.5-116.6% for all tocopherols and tocotrienols. The developed DLLME method was successfully applied to cereals: rice, barley, oat, wheat, corn and millet. This new sample preparation approach represents an inexpensive, rapid, simple and precise sample cleanup and concentration method for the determination of tocopherols and tocotrienols in cereals.
    MeSH terms: Acetonitriles/chemistry; Analysis of Variance; Carbon Tetrachloride/chemistry; Edible Grain/chemistry*; Chromatography, High Pressure Liquid/methods; Plant Extracts/chemistry; Sodium Chloride/chemistry; Reproducibility of Results; Linear Models; Tocopherols/analysis*; Tocopherols/isolation & purification; Tocopherols/chemistry; Tocotrienols/analysis*; Tocotrienols/isolation & purification; Tocotrienols/chemistry; Chromatography, Reverse-Phase/methods*; Limit of Detection; Liquid Phase Microextraction/methods*
  3. Drake R
    Br J Nurs, 2013 Jan-Feb;22(2):95-100.
    PMID: 23587892
    In 2010, the Royal College of Nursing asked: 'What is the optimal level and mix of nurses required to deliver quality care as cost-effectively as possible?' This question implies there is a relationship between staffing levels, quality of care and financial efficiency. This paper examines the relationship between the staff budget, the number of staff required to achieve a target level of care and the actual number of staff employed in seven hospitals in Malaysia. It seeks to critically evaluate local challenges arising from staff budgeting/planning procedures, identify general issues that apply beyond Malaysian healthcare institutions and, finally, to propose a model that combines finance, staffing and level of care.
    MeSH terms: Budgets/statistics & numerical data; Delivery of Health Care/economics; Delivery of Health Care/organization & administration*; Hospitals, Public/economics; Hospitals, Public/organization & administration*; Humans; Malaysia; Nursing Staff, Hospital/economics; Nursing Staff, Hospital/organization & administration*; Personnel Staffing and Scheduling/economics; Personnel Staffing and Scheduling/organization & administration*; Hospitals, Private/economics; Hospitals, Private/organization & administration*; Workload/economics; Workload/statistics & numerical data
  4. Saidu M, Yuzir A, Salim MR, Salmiati, Azman S, Abdullah N
    Bioresour Technol, 2013 Aug;141:174-6.
    PMID: 23588120 DOI: 10.1016/j.biortech.2013.03.111
    Anaerobic digestion for palm oil mill effluent (POME) is widely known for its potential in biogass production. In this study, the potential of using cattle manure for biogas production in complete mix anaerobic bioreactor was investigated using POME at unregulated pH and temperature. Two identical bioreactors were used in this study; namely R1 and R2 fed with cattle manure without and with POME as inoculum, respectively. Both bioreactors were allowed for five days to run in batch mode followed by semi continuous operations at HRT of 20 days. R2 produced 41% methane content compared to 18% produced in R1. A better COD percentage reduction of 45% was found in R2 which was operated with POME as inoculum compared to R1 with 35%. These results indicated that POME as inoculum has an influence on the start-up time and the rate of biogas produced.This findings will help in waste reduction.
    MeSH terms: Animals; Bacteria, Anaerobic/metabolism*; Cattle; Industrial Waste*; Manure*; Plant Oils*; Waste Management/methods; Biofuels*
  5. Abdul-Salim I, Embong Z, Khairy-Shamel ST, Raja-Azmi MN
    Clin Ophthalmol, 2013;7:703-6.
    PMID: 23589678 DOI: 10.2147/OPTH.S42208
    Herein, we report our experience in treating extensive traumatic submacular hemorrhage with a single dose of intravitreal ranibizumab. A 23-year-old healthy Malay man presented with a progressive reduction of central vision in the left eye of 2 days' duration following a history of blunt trauma. Visual acuity was reduced to counting fingers. Examination revealed infero-temporal subconjunctival hemorrhage, traumatic anterior uveitis, and an extensive sub-macular hemorrhage with suspicion of a choroidal rupture in the affected eye. He was initially treated conservatively with topical prednisolone acetate 1%. The subconjunctival hemorrhage and anterior uveitis resolved but his vision remained poor with minimal resolution of the submacular hemorrhage at 1 week follow-up (day 12 post-trauma). In view of the poor resolution of submacular hemorrhage, he was treated with a single dose of 0.5 mg intravitreal ranibizumab at day 20 post-trauma. At 4 weeks post-intravitreal ranibizumab, there was an improvement in visual acuity (from counting fingers to 6/45) and complete resolution of the submacular hemorrhage with presence of a choroidal rupture scar temporal to the fovea, which was not seen clearly at presentation due to obscuration by blood. His visual acuity further improved to 6/18 at 3 months post-trauma. Although this single case had a favorable outcome, a large population cohort study is needed to establish the effectiveness of intravitreal ranibizumab in treating extensive traumatic submacular hemorrhage.
    MeSH terms: Ranibizumab; Cicatrix; Eye Injuries; Follow-Up Studies; Fovea Centralis; Humans; Malaysia; Male; Prednisolone; Retinal Hemorrhage; Uveitis, Anterior; Visual Acuity
  6. Schuh AJ, Guzman H, Tesh RB, Barrett AD
    Vector Borne Zoonotic Dis, 2013 Jul;13(7):479-88.
    PMID: 23590316 DOI: 10.1089/vbz.2011.0870
    Five genotypes (GI-V) of Japanese encephalitis virus (JEV) have been identified, all of which have distinct geographical distributions and epidemiologies. It is thought that JEV originated in the Indonesia-Malaysia region from an ancestral virus. From that ancestral virus GV diverged, followed by GIV, GIII, GII, and GI. Genotype IV appears to be confined to the Indonesia-Malaysia region, as GIV has been isolated in Indonesia from mosquitoes only, while GV has been isolated on three occasions only from a human in Malaysia and mosquitoes in China and South Korea. In contrast, GI-III viruses have been isolated throughout Asia and Australasia from a variety of hosts. Prior to this study only 13 JEV isolates collected from the Indonesian archipelago had been studied genetically. Therefore the sequences of the envelope (E) gene of 24 additional Indonesian JEV isolates, collected throughout the archipelago between 1974 and 1987, were determined and a series of molecular adaptation analyses were performed. Phylogenetic analysis indicated that over a 14-year time span three genotypes of JEV circulated throughout Indonesia, and a statistically significant association between the year of virus collection and genotype was revealed: isolates collected between 1974 and 1980 belonged to GII, isolates collected between 1980 and 1981 belonged to GIV, and isolates collected in 1987 belonged to GIII. Interestingly, three of the GII Indonesian isolates grouped with an isolate that was collected during the JE outbreak that occurred in Australia in 1995, two of the GIII Indonesian isolates were closely related to a Japanese isolate collected 40 years previously, and two Javanese GIV isolates possessed six amino acid substitutions within the E protein when compared to a previously sequenced GIV isolate collected in Flores. Several amino acids within the E protein of the Indonesian isolates were found to be under directional evolution and/or co-evolution. Conceivably, the tropical climate of the Indonesia/Malaysia region, together with its plethora of distinct fauna and flora, may have driven the emergence and evolution of JEV. This is consistent with the extensive genetic diversity seen among the JEV isolates observed in this study, and further substantiates the hypothesis that JEV originated in the Indonesia-Malaysia region.
    MeSH terms: Amino Acid Sequence; Animals; Base Sequence; Encephalitis Virus, Japanese/classification; Encephalitis Virus, Japanese/genetics*; Encephalitis Virus, Japanese/isolation & purification; Encephalitis, Japanese/epidemiology*; Encephalitis, Japanese/virology; Genotype; Humans; Indonesia/epidemiology; Insect Vectors/virology*; Models, Molecular; Culicidae/virology*; Phylogeny; Recombination, Genetic; RNA, Viral/genetics; RNA, Viral/chemistry; Genetic Variation*; Viral Proteins/genetics; Sequence Alignment; Genome, Viral/genetics*; Sequence Analysis, DNA; Molecular Epidemiology; Evolution, Molecular
  7. Sabanayagam C, Teo BW, Tai ES, Jafar TH, Wong TY
    BMC Nephrol, 2013;14:86.
    PMID: 23590421 DOI: 10.1186/1471-2369-14-86
    Chronic kidney disease (CKD) is an emerging public health problem worldwide. Previous studies have shown an association between blood pressure (BP) and CKD. However, it is not clear if there are ethnic differences in this association. We examined the association between BP and CKD in a multi-ethnic Asian population in Singapore.
    MeSH terms: Adult; Aged; Aged, 80 and over; Blood Pressure/physiology*; Ethnic Groups/ethnology; Female; Humans; India/ethnology; Malaysia/ethnology; Male; Middle Aged; Population Surveillance/methods; Asian Continental Ancestry Group/ethnology*; Renal Insufficiency, Chronic/diagnosis*; Renal Insufficiency, Chronic/ethnology*; Renal Insufficiency, Chronic/physiopathology
  8. Shi Yeen TN, Pathmanathan R, Shiran MS, Ahmad Zaid FA, Cheah YK
    J Biomed Sci, 2013 Apr 16;20:22.
    PMID: 23590575 DOI: 10.1186/1423-0127-20-22
    BACKGROUND: Somatic mutations of the epidermal growth factor receptor (EGFR) are reportedly associated with various responses in non-small cell lung cancer (NSCLC) patients receiving the anti-EGFR agents. Detection of the mutation therefore plays an important role in therapeutic decision making. The aim of this study was to detect EGFR mutations in formalin fixed paraffin embedded (FFPE) samples using both Scorpion ARMS and high resolution melt (HRM) assay, and to compare the sensitivity of these methods.

    RESULTS: All of the mutations were found in adenocarcinoma, except one that was in squamous cell carcinoma. The mutation rate was 45.7% (221/484). Complex mutations were also observed, wherein 8 tumours carried 2 mutations and 1 tumour carried 3 mutations.

    CONCLUSIONS: Both methods detected EGFR mutations in FFPE samples. HRM assays gave more EGFR positive results compared to Scorpion ARMS.

    MeSH terms: Biopsy; Carcinoma, Non-Small-Cell Lung/genetics*; Carcinoma, Non-Small-Cell Lung/pathology; Formaldehyde/metabolism; Formaldehyde/chemistry*; Humans; Lung Neoplasms/genetics*; Lung Neoplasms/pathology; Mutation*; Paraffin Embedding; ErbB Receptors/genetics*
  9. Kiani MJ, Ahmadi MT, Karimi Feiz Abadi H, Rahmani M, Hashim A, Che Harun FK
    Nanoscale Res Lett, 2013;8(1):173.
    PMID: 23590751 DOI: 10.1186/1556-276X-8-173
    Graphene has attracted great interest because of unique properties such as high sensitivity, high mobility, and biocompatibility. It is also known as a superior candidate for pH sensing. Graphene-based ion-sensitive field-effect transistor (ISFET) is currently getting much attention as a novel material with organic nature and ionic liquid gate that is intrinsically sensitive to pH changes. pH is an important factor in enzyme stabilities which can affect the enzymatic reaction and broaden the number of enzyme applications. More accurate and consistent results of enzymes must be optimized to realize their full potential as catalysts accordingly. In this paper, a monolayer graphene-based ISFET pH sensor is studied by simulating its electrical measurement of buffer solutions for different pH values. Electrical detection model of each pH value is suggested by conductance modelling of monolayer graphene. Hydrogen ion (H+) concentration as a function of carrier concentration is proposed, and the control parameter (Ƥ) is defined based on the electro-active ions absorbed by the surface of the graphene with different pH values. Finally, the proposed new analytical model is compared with experimental data and shows good overall agreement.
  10. Chong SK, Dee CF, Abdul Rahman S
    Nanoscale Res Lett, 2013;8(1):174.
    PMID: 23590803 DOI: 10.1186/1556-276X-8-174
    Silicon/zinc oxide (Si/ZnO) core-shell nanowires (NWs) were prepared on a p-type Si(111) substrate using a two-step growth process. First, indium seed-coated Si NWs (In/Si NWs) were synthesized using a plasma-assisted hot-wire chemical vapor deposition technique. This was then followed by the growth of a ZnO nanostructure shell layer using a vapor transport and condensation method. By varying the ZnO growth time from 0.5 to 2 h, different morphologies of ZnO nanostructures, such as ZnO nanoparticles, ZnO shell layer, and ZnO nanorods were grown on the In/Si NWs. The In seeds were believed to act as centers to attract the ZnO molecule vapors, further inducing the lateral growth of ZnO nanorods from the Si/ZnO core-shell NWs via a vapor-liquid-solid mechanism. The ZnO nanorods had a tendency to grow in the direction of [0001] as indicated by X-ray diffraction and high resolution transmission electron microscopy analyses. We showed that the Si/ZnO core-shell NWs exhibit a broad visible emission ranging from 400 to 750 nm due to the combination of emissions from oxygen vacancies in ZnO and In2O3 structures and nanocrystallite Si on the Si NWs. The hierarchical growth of straight ZnO nanorods on the core-shell NWs eventually reduced the defect (green) emission and enhanced the near band edge (ultraviolet) emission of the ZnO.
    MeSH terms: Indium; Oxygen; Silicon; X-Ray Diffraction; Zinc Oxide; Nanotubes; Microscopy, Electron, Transmission; Nanostructures; Nanoparticles; Nanowires
  11. Chow MF, Yusop Z, Shirazi SM
    Environ Monit Assess, 2013 Oct;185(10):8321-31.
    PMID: 23591675 DOI: 10.1007/s10661-013-3175-6
    Information on the pollution level and the influence of hydrologic regime on the stormwater pollutant loading in tropical urban areas are still scarce. More local data are still required because rainfall and runoff generation processes in tropical environment are very different from the temperate regions. This study investigated the extent of urban runoff pollution in residential, commercial, and industrial catchments in the south of Peninsular Malaysia. Stormwater samples and flow rate data were collected from 51 storm events. Samples were analyzed for total suspended solids, 5-day biochemical oxygen demand, chemical oxygen demand, oil and grease (O&G), nitrate nitrogen (NO3-N), nitrite nitrogen, ammonia nitrogen, soluble reactive phosphorus, total phosphorus (TP), and zinc (Zn). It was found that the event mean concentrations (EMCs) of pollutants varied greatly between storm characteristics and land uses. The results revealed that site EMCs for residential catchment were lower than the published data but higher for the commercial and industrial catchments. All rainfall variables were negatively correlated with EMCs of most pollutants except for antecedent dry days (ADD). This study reinforced the earlier findings on the importance of ADD for causing greater EMC values with exceptions for O&G, NO3-N, TP, and Zn. In contrast, the pollutant loadings are influenced primarily by rainfall depth, mean intensity, and max 5-min intensity in all the three catchments. Overall, ADD is an important variable in multiple linear regression models for predicting the EMC values in the tropical urban catchments.
    MeSH terms: Environmental Monitoring*; Industry; Malaysia; Nitrogen/analysis; Phosphorus/analysis; Rain; Water Movements; Water Pollutants, Chemical/analysis*; Water Pollution, Chemical/statistics & numerical data*
  12. Abd Kadir SL, Yaakob H, Mohamed Zulkifli R
    J Nat Med, 2013 Oct;67(4):677-89.
    PMID: 23591999 DOI: 10.1007/s11418-013-0767-y
    Dengue fever causes mortality and morbidity around the world, specifically in the Tropics and subtropic regions, which has been of major concern to governments and the World Health Organization (WHO). As a consequence, the search for new anti-dengue agents from medicinal plants has assumed more urgency than in the past. Medicinal plants have been used widely to treat a variety of vector ailments such as malaria. The demand for plant-based medicines is growing as they are generally considered to be safer, non-toxic and less harmful than synthetic drugs. This article reviews potential anti-dengue activities from plants distributed around the world. Sixty-nine studies from 1997 to 2012 describe 31 different species from 24 families that are known for their anti-dengue activities. About ten phytochemicals have been isolated from 11 species, among which are compounds with the potential for development of dengue treatment. Crude extracts and essential oils obtained from 31 species showed a broad activity against Flavivirus. Current studies show that natural products represent a rich potential source of new anti-dengue compounds. Further ethnobotanical surveys and laboratory investigations are needed established the potential of identified species in contributing to dengue control.
    MeSH terms: Antiviral Agents/pharmacology; Antiviral Agents/therapeutic use*; Antiviral Agents/chemistry; Dengue/drug therapy*; Dengue/epidemiology; Dengue/virology; Humans; Phytotherapy*; Plant Extracts/pharmacology; Plant Extracts/therapeutic use
  13. Yahaya B, McLachlan G, McCorquodale C, Collie D
    PLoS One, 2013;8(4):e58930.
    PMID: 23593124 DOI: 10.1371/journal.pone.0058930
    BACKGROUND: Understanding the way in which the airway heals in response to injury is fundamental to dissecting the mechanisms underlying airway disease pathology. As only limited data is available in relation to the in vivo characterisation of the molecular features of repair in the airway we sought to characterise the dynamic changes in gene expression that are associated with the early response to physical injury in the airway wall.

    METHODOLOGY/PRINCIPAL FINDINGS: We profiled gene expression changes in the airway wall using a large animal model of physical injury comprising bronchial brush biopsy in anaesthetised sheep. The experimental design featured sequential studies in the same animals over the course of a week and yielded data relating to the response at 6 hours, and 1, 3 and 7 days after injury. Notable features of the transcriptional response included the early and sustained preponderance of down-regulated genes associated with angiogenesis and immune cell activation, selection and differentiation. Later features of the response included the up-regulation of cell cycle genes at d1 and d3, and the latter pronounced up-regulation of extracellular matrix-related genes at d3 and d7.

    CONCLUSIONS/SIGNIFICANCE: It is possible to follow the airway wall response to physical injury in the same animal over the course of time. Transcriptional changes featured coordinate expression of functionally related genes in a reproducible manner both within and between animals. This characterisation will provide a foundation against which to assess the perturbations that accompany airway disease pathologies of comparative relevance.

    MeSH terms: Animals; Gene Expression Regulation*; Humans; Microvilli/genetics; Respiratory System/injuries*; Respiratory System/metabolism*; Wound Healing/genetics*; Cluster Analysis; Computational Biology; Respiratory Mucosa/cytology; Respiratory Mucosa/metabolism; Gene Expression Profiling; Molecular Sequence Annotation
  14. Hu Y, Tan PT, Tan TW, August JT, Khan AM
    PLoS One, 2013;8(4):e59994.
    PMID: 23593157 DOI: 10.1371/journal.pone.0059994
    The rapid mutation of human immunodeficiency virus-type 1 (HIV-1) and the limited characterization of the composition and incidence of the variant population are major obstacles to the development of an effective HIV-1 vaccine. This issue was addressed by a comprehensive analysis of over 58,000 clade B HIV-1 protein sequences reported over at least 26 years. The sequences were aligned and the 2,874 overlapping nonamer amino acid positions of the viral proteome, each a possible core binding domain for human leukocyte antigen molecules and T-cell receptors, were quantitatively analyzed for four patterns of sequence motifs: (1) "index", the most prevalent sequence; (2) "major" variant, the most common variant sequence; (3) "minor" variants, multiple different sequences, each with an incidence less than that of the major variant; and (4) "unique" variants, each observed only once in the alignment. The collective incidence of the major, minor, and unique variants at each nonamer position represented the total variant population for the position. Positions with more than 50% total variants contained correspondingly reduced incidences of index and major variant sequences and increased minor and unique variants. Highly diverse positions, with 80 to 98% variant nonamer sequences, were present in each protein, including 5% of Gag, and 27% of Env and Nef, each. The multitude of different variant nonamer sequences (i.e. nonatypes; up to 68%) at the highly diverse positions, represented by the major, multiple minor, and multiple unique variants likely supported variants function both in immune escape and as altered peptide ligands with deleterious T-cell responses. The patterns of mutational change were consistent with the sequences of individual HXB2 and C1P viruses and can be considered applicable to all HIV-1 viruses. This characterization of HIV-1 protein mutation provides a foundation for the design of peptide-based vaccines and therapeutics.
    MeSH terms: Amino Acid Sequence; Humans; Molecular Sequence Data; Mutation; Genetic Variation*; Viral Proteins/genetics*; Viral Proteins/chemistry; HIV-1/classification; HIV-1/genetics*; Sequence Alignment; Proteome; Amino Acid Motifs; Databases, Genetic; env Gene Products, Human Immunodeficiency Virus/genetics; env Gene Products, Human Immunodeficiency Virus/chemistry; gag Gene Products, Human Immunodeficiency Virus/genetics; gag Gene Products, Human Immunodeficiency Virus/chemistry
  15. Lye SH, Chahil JK, Bagali P, Alex L, Vadivelu J, Ahmad WA, et al.
    PLoS One, 2013;8(4):e60729.
    PMID: 23593297 DOI: 10.1371/journal.pone.0060729
    Familial hypercholesterolemia (FH) is an autosomal dominant disorder characterized by elevations in total cholesterol (TC) and low density lipoprotein cholesterol (LDLc). Development of FH can result in the increase of risk for premature cardiovascular diseases (CVD). FH is primarily caused by genetic variations in Low Density Lipoprotein Receptor (LDLR), Apolipoprotein B (APOB) or Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) genes. Although FH has been extensively studied in the Caucasian population, there are limited reports of FH mutations in the Asian population. We investigated the association of previously reported genetic variants that are involved in lipid regulation in our study cohort. A total of 1536 polymorphisms previously implicated in FH were evaluated in 141 consecutive patients with clinical FH (defined by the Dutch Lipid Clinic Network criteria) and 111 unrelated control subjects without FH using high throughput microarray genotyping platform. Fourteen Single Nucleotide Polymorphisms (SNPs) were found to be significantly associated with FH, eleven with increased FH risk and three with decreased FH risk. Of the eleven SNPs associated with an increased risk of FH, only one SNP was found in the LDLR gene, seven in the APOB gene and three in the PCSK9 gene. SNP rs12720762 in APOB gene is associated with the highest risk of FH (odds ratio 14.78, p<0.001). Amongst the FH cases, 108 out of 141 (76.60%) have had at least one significant risk-associated SNP. Our study adds new information and knowledge on the genetic polymorphisms amongst Asians with FH, which may serve as potential markers in risk prediction and disease management.
    MeSH terms: Adult; Apolipoproteins B/genetics*; Female; Gene Frequency; Genotype; Humans; Hyperlipoproteinemia Type II/genetics*; Hyperlipoproteinemia Type II/metabolism*; Hyperlipoproteinemia Type II/pathology; Malaysia; Male; Middle Aged; Receptors, LDL/genetics*; Serine Endopeptidases/genetics*; Cohort Studies; Polymorphism, Single Nucleotide*; Proprotein Convertases/genetics*; Lipid Metabolism/genetics*
  16. Woodcock P, Edwards DP, Newton RJ, Vun Khen C, Bottrell SH, Hamer KC
    PLoS One, 2013;8(4):e60756.
    PMID: 23593302 DOI: 10.1371/journal.pone.0060756
    Trophic organisation defines the flow of energy through ecosystems and is a key component of community structure. Widespread and intensifying anthropogenic disturbance threatens to disrupt trophic organisation by altering species composition and relative abundances and by driving shifts in the trophic ecology of species that persist in disturbed ecosystems. We examined how intensive disturbance caused by selective logging affects trophic organisation in the biodiversity hotspot of Sabah, Borneo. Using stable nitrogen isotopes, we quantified the positions in the food web of 159 leaf-litter ant species in unlogged and logged rainforest and tested four predictions: (i) there is a negative relationship between the trophic position of a species in unlogged forest and its change in abundance following logging, (ii) the trophic positions of species are altered by logging, (iii) disturbance alters the frequency distribution of trophic positions within the ant assemblage, and (iv) disturbance reduces food chain length. We found that ant abundance was 30% lower in logged forest than in unlogged forest but changes in abundance of individual species were not related to trophic position, providing no support for prediction (i). However, trophic positions of individual species were significantly higher in logged forest, supporting prediction (ii). Consequently, the frequency distribution of trophic positions differed significantly between unlogged and logged forest, supporting prediction (iii), and food chains were 0.2 trophic levels longer in logged forest, the opposite of prediction (iv). Our results demonstrate that disturbance can alter trophic organisation even without trophically-biased changes in community composition. Nonetheless, the absence of any reduction in food chain length in logged forest suggests that species-rich arthropod food webs do not experience trophic downgrading or a related collapse in trophic organisation despite the disturbance caused by logging. These food webs appear able to bend without breaking in the face of some forms of anthropogenic disturbance.
    MeSH terms: Animals; Ants/physiology*; Malaysia; Forestry*; Biodiversity*
  17. Abdullah A, Deris S, Mohamad MS, Anwar S
    PLoS One, 2013;8(4):e61258.
    PMID: 23593445 DOI: 10.1371/journal.pone.0061258
    One of the key aspects of computational systems biology is the investigation on the dynamic biological processes within cells. Computational models are often required to elucidate the mechanisms and principles driving the processes because of the nonlinearity and complexity. The models usually incorporate a set of parameters that signify the physical properties of the actual biological systems. In most cases, these parameters are estimated by fitting the model outputs with the corresponding experimental data. However, this is a challenging task because the available experimental data are frequently noisy and incomplete. In this paper, a new hybrid optimization method is proposed to estimate these parameters from the noisy and incomplete experimental data. The proposed method, called Swarm-based Chemical Reaction Optimization, integrates the evolutionary searching strategy employed by the Chemical Reaction Optimization, into the neighbouring searching strategy of the Firefly Algorithm method. The effectiveness of the method was evaluated using a simulated nonlinear model and two biological models: synthetic transcriptional oscillators, and extracellular protease production models. The results showed that the accuracy and computational speed of the proposed method were better than the existing Differential Evolution, Firefly Algorithm and Chemical Reaction Optimization methods. The reliability of the estimated parameters was statistically validated, which suggests that the model outputs produced by these parameters were valid even when noisy and incomplete experimental data were used. Additionally, Akaike Information Criterion was employed to evaluate the model selection, which highlighted the capability of the proposed method in choosing a plausible model based on the experimental data. In conclusion, this paper presents the effectiveness of the proposed method for parameter estimation and model selection problems using noisy and incomplete experimental data. This study is hoped to provide a new insight in developing more accurate and reliable biological models based on limited and low quality experimental data.
    MeSH terms: Algorithms*; Biochemical Phenomena*; Cell Physiological Phenomena/physiology*; Computer Simulation; Models, Biological*; Software*; Computational Biology/methods*; Systems Biology/methods*; Search Engine/methods
  18. Teh HF, Neoh BK, Hong MP, Low JY, Ng TL, Ithnin N, et al.
    PLoS One, 2013;8(4):e61344.
    PMID: 23593468 DOI: 10.1371/journal.pone.0061344
    To better understand lipid biosynthesis in oil palm mesocarp, in particular the differences in gene regulation leading to and including de novo fatty acid biosynthesis, a multi-platform metabolomics technology was used to profile mesocarp metabolites during six critical stages of fruit development in comparatively high- and low-yielding oil palm populations. Significantly higher amino acid levels preceding lipid biosynthesis and nucleosides during lipid biosynthesis were observed in a higher yielding commercial palm population. Levels of metabolites involved in glycolysis revealed interesting divergence of flux towards glycerol-3-phosphate, while carbon utilization differences in the TCA cycle were proven by an increase in malic acid/citric acid ratio. Apart from insights into the regulation of enhanced lipid production in oil palm, these results provide potentially useful metabolite yield markers and genes of interest for use in breeding programmes.
    MeSH terms: Amino Acids/metabolism; Breeding/methods; Chromatography, Liquid; Fruit/growth & development; Fruit/metabolism*; Lipids/biosynthesis*; Malates/metabolism; Gas Chromatography-Mass Spectrometry; Biomarkers/metabolism; Gene Expression Regulation, Plant/physiology*; Gene Expression Regulation, Developmental/physiology*; Citric Acid/metabolism; Principal Component Analysis; Arecaceae/genetics; Arecaceae/metabolism*; Metabolomics/methods
  19. Thio CL, Yusof R, Abdul-Rahman PS, Karsani SA
    PLoS One, 2013;8(4):e61444.
    PMID: 23593481 DOI: 10.1371/journal.pone.0061444
    Chikungunya virus (CHIKV) is an emerging mosquito-borne alphavirus that has caused multiple unprecedented and re-emerging outbreaks in both tropical and temperate countries. Despite ongoing research efforts, the underlying factors involved in facilitating CHIKV replication during early infection remains ill-characterized. The present study serves to identify host proteins modulated in response to early CHIKV infection using a proteomics approach.
    MeSH terms: Humans; RNA, Messenger/genetics; Viral Proteins/metabolism*; Alphavirus Infections/metabolism*; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Proteome*; Chikungunya Fever
  20. Rovie-Ryan JJ, Zainuddin ZZ, Marni W, Ahmad AH, Ambu LN, Payne J
    Asian Pac J Trop Biomed, 2013 Feb;3(2):95-9.
    PMID: 23593586 DOI: 10.1016/S2221-1691(13)60031-3
    To demonstrate a noninvasive large mammalian genetic sampling method using blood meal obtained from a tabanid fly.
    MeSH terms: Animals; Diet/veterinary; Diptera/genetics; Diptera/physiology*; Female; Indonesia; Insect Bites and Stings/blood; Insect Bites and Stings/veterinary*; Molecular Sequence Data; Perissodactyla*; Phylogeny; Polymerase Chain Reaction/veterinary; Sequence Analysis, DNA/veterinary; Food Chain*; Endangered Species
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