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  1. Fulltext Enhancement of Versatile Extracellular Cellulolytic and Hemicellulolytic Enzyme Productions by Lactobacillus plantarum RI 11 Isolated from Malaysian Food Using Renewable Natural Polymers
    Mohamad Zabidi NA, Foo HL, Loh TC, Mohamad R, Abdul Rahim R
    Molecules, 2020 Jun 03;25(11).
    PMID: 32503356 DOI: 10.3390/molecules25112607
    Lactobacillus plantarum RI 11 was reported recently to be a potential lignocellulosic biomass degrader since it has the capability of producing versatile extracellular cellulolytic and hemicellulolytic enzymes. Thus, this study was conducted to evaluate further the effects of various renewable natural polymers on the growth and production of extracellular cellulolytic and hemicellulolytic enzymes by this novel isolate. Basal medium supplemented with molasses and yeast extract produced the highest cell biomass (log 10.51 CFU/mL) and extracellular endoglucanase (11.70 µg/min/mg), exoglucanase (9.99 µg/min/mg), β-glucosidase (10.43 nmol/min/mg), and mannanase (8.03 µg/min/mg), respectively. Subsequently, a statistical optimization approach was employed for the enhancement of cell biomass, and cellulolytic and hemicellulolytic enzyme productions. Basal medium that supplemented with glucose, molasses and soybean pulp (F5 medium) or with rice straw, yeast extract and soybean pulp (F6 medium) produced the highest cell population of log 11.76 CFU/mL, respectively. However, formulated F12 medium supplemented with glucose, molasses and palm kernel cake enhanced extracellular endoglucanase (4 folds), exoglucanase (2.6 folds) and mannanase (2.6 folds) specific activities significantly, indicating that the F12 medium could induce the highest production of extracellular cellulolytic and hemicellulolytic enzymes concomitantly. In conclusion, L. plantarum RI 11 is a promising and versatile bio-transformation agent for lignocellulolytic biomass.
  2. Fulltext Rapid Evaluation and Optimization of Medium Components Governing Tryptophan Production by Pediococcus acidilactici TP-6 Isolated from Malaysian Food via Statistical Approaches
    Lim YH, Foo HL, Loh TC, Mohamad R, Abdul Rahim R
    Molecules, 2020 Feb 11;25(4).
    PMID: 32054138 DOI: 10.3390/molecules25040779
    Tryptophan is one of the most extensively used amino acids in livestock industry owing to its effectiveness in enhancing the growth performance of animals. Conventionally, the production of tryptophan relies heavily on genetically modified Escherichia coli but its pathogenicity is a great concern. Our recent study demonstrated that a lactic acid bacterium (LAB), Pediococcus acidilactici TP-6 that isolated from Malaysian food was a promising tryptophan producer. However, the tryptophan production must enhance further for viable industrial application. Hence, the current study evaluated the effects of medium components and optimized the medium composition for tryptophan production by P. acidilactici TP-6 statistically using Plackett-Burman Design, and Central Composite Design. The optimized medium containing molasses (14.06 g/L), meat extract (23.68 g/L), urea (5.56 g/L) and FeSO4 (0.024 g/L) significantly enhanced the tryptophan production by 150% as compared to the control de Man, Rogosa and Sharpe medium. The findings obtained in this study revealed that rapid evaluation and effective optimization of medium composition governing tryptophan production by P. acidilactici TP-6 were feasible via statistical approaches. Additionally, the current findings reveal the potential of utilizing LAB as a safer alternative tryptophan producer and provides insight for future exploitation of various amino acid productions by LAB.
  3. Fulltext Microbial synthesis of zinc oxide nanoparticles and their potential application as an antimicrobial agent and a feed supplement in animal industry: a review
    Mohd Yusof H, Mohamad R, Zaidan UH, Abdul Rahman NA
    J Anim Sci Biotechnol, 2019;10:57.
    PMID: 31321032 DOI: 10.1186/s40104-019-0368-z
    In recent years, zinc oxide nanoparticles (ZnO NPs) have gained tremendous attention attributed to their unique properties. Notably, evidence has shown that zinc is an important nutrient in living organisms. As such, both prokaryotes and eukaryotes including bacteria, fungi and yeast are exploited for the synthesis of ZnO NPs by using microbial cells or enzyme, protein and other biomolecules compounds in either an intracellular or extracellular route. ZnO NPs exhibit antimicrobial properties, however, the properties of nanoparticles (NPs) are depended upon on their size and shape, which make them specific for various applications. Nevertheless, the desired size and shape of NPs can be obtained through the optimization process of microbes mediated synthesis by manipulating their reaction conditions. It should be noted that ZnO NPs are synthesized by various chemical and physical methods. Nonetheless, these methods are expensive and not environmentally friendly. On that account, the microbes mediated synthesis of ZnO NPs have rapidly evolved recently where the microbes are cleaner, eco-friendly, non-toxic and biocompatible as the alternatives to chemical and physical practices. Moreover, zinc in the form of NPs is more effective than their bulk counterparts and thus, they have been explored for many potential applications including in animals industry. Notably, with the advent of multi-drug resistant strains, ZnO NPs have emerged as the potential antimicrobial agents. This is mainly due to their superior properties in combating a broad spectrum of pathogens. Moreover, zinc is known as an essential trace element for most of the biological function in the animal's body. As such, the applications of ZnO NPs have been reported to significantly enhance the health and production of the farm animals. Thus, this paper reviews the biological synthesis of ZnO NPs by the microbes, the mechanisms of the biological synthesis, parameters for the optimization process and their potential application as an antimicrobial agent and feed supplement in the animal industry as well as their toxicological hazards on animals.
  4. Fulltext Comparative studies of versatile extracellular proteolytic activities of lactic acid bacteria and their potential for extracellular amino acid productions as feed supplements
    Lim YH, Foo HL, Loh TC, Mohamad R, Abdullah N
    J Anim Sci Biotechnol, 2019;10:15.
    PMID: 30886709 DOI: 10.1186/s40104-019-0323-z
    Background: Increasing understanding on the functions of amino acids (AA) has led to new commercial applications and expansion of the worldwide markets. However, the current technologies rely heavily on non-food grade microorganism and chemical synthesis for the production of AA. Several studies reported that lactic acid bacteria (LAB) have the capability of producing AA owing to their well-established proteolytic system and amino acid biosynthesis genes. Hence, the objectives of this study were to explore the extracellular proteolytic activity of LAB isolated from various Malaysian fermented foods and their potential to produce AA extracellularly as feed supplements.

    Results: All the studied LAB isolates were versatile extracellular protease producers, whereby extracellular protease activities were detected from acidic to alkaline pH (pH 5, pH 6.5, pH 8) using qualitative and quantitative proteolytic assays. The highest proteolytic activity at pH 5 (15.76 U/mg) and pH 8 (19.42 U/mg) was achieved by Lactobacillus plantarum RG14, while Lactobacillus plantarum RS5 exhibited the highest proteolytic activity of 17.22 U/mg at pH 6.5. As for the results of AA production conducted in de Man, Rogosa and Sharpe medium and analysed by high pressure liquid chromatography system, all LAB isolates were capable of producing an array of AA. Generally, Pediococcus sp. showed greater ability for AA production as compared to Lactobacillus sp. Moreover, the studied LAB were able to produce a few major feed supplement AA such as methionine, lysine, threonine and tryptophan. P. pentosaceus TL-3 recorded the highest methionine and threonine productivity of 3.72 mg/L/h and 5.58 mg/L/h respectively. However, L. plantarum I-UL4 demonstrated a lysine productivity of 1.24 mg/L/h, while P. acidilactici TP-6 achieved up to 1.73 mg/L/h of tryptophan productivity.

    Conclusion: All the 17 studied LAB isolates possessed versatile extracellular proteolytic system and have vast capability of producing various amino acids including a few major feed supplement AA such as methionine, lysine, threonine and tryptophan. Despite AA production was strain dependent, the studied LAB isolates possessed vast potential and can be exploited further as a bio-agent or an alternative amino acids and bioactive peptide producers.

  5. Clinical recognition of elder maltreatment and intention to report among primary care doctors
    Mohd Mydin FH, Othman S, Choo WY, Hairi NNM, Hairi FM, Syed Karim SN, et al.
    J Elder Abuse Negl, 2020 02 21;32(1):72-83.
    PMID: 32085693 DOI: 10.1080/08946566.2020.1731640
    This study aimed to determine the primary care doctors' ability to recognize elder maltreatment and their intentions to report on such conditions. About 358 primary care doctors participated in this study. Outcomes were assessed using a validated five context-relevant clinical vignettes. Primary care doctor's recognition of sexual abuse was highest (91.0%); while the lowest (70.2%) in case signifying physical abuse. Despite being able to ascertain elder maltreatment, the intention to report the event is generally low even for cases exemplifying physical abuse, emotional abuse and neglect. However, intentions to report cases of sexual and financial abuse are 86.9% and 73.5% respectively. Findings highlighted the uncertainties of primary care doctors in distinguishing the clinical findings of non-accidental injuries and injuries due to acts of maltreatment. This provides support for educational intervention and guidelines or policies to improve the knowledge and skills of primary care doctors to intervene in elder maltreatment.
  6. Fulltext A refined medium to enhance the antimicrobial activity of postbiotic produced by Lactiplantibacillus plantarum RS5
    Ooi MF, Foo HL, Loh TC, Mohamad R, Rahim RA, Ariff A
    Sci Rep, 2021 Apr 07;11(1):7617.
    PMID: 33828119 DOI: 10.1038/s41598-021-87081-6
    Postbiotic RS5, produced by Lactiplantibacillus plantarum RS5, has been identified as a promising alternative feed supplement for various livestock. This study aimed to lower the production cost by enhancing the antimicrobial activity of the postbiotic RS5 by improving the culture density of L. plantarum RS5 and reducing the cost of growth medium. A combination of conventional and statistical-based approaches (Fractional Factorial Design and Central Composite Design of Response Surface Methodology) was employed to develop a refined medium for the enhancement of the antimicrobial activity of postbiotic RS5. A refined medium containing 20 g/L of glucose, 27.84 g/L of yeast extract, 5.75 g/L of sodium acetate, 1.12 g/L of Tween 80 and 0.05 g/L of manganese sulphate enhanced the antimicrobial activity of postbiotic RS5 by 108%. The cost of the production medium was reduced by 85% as compared to the commercially available de Man, Rogosa and Sharpe medium that is typically used for Lactobacillus cultivation. Hence, the refined medium has made the postbiotic RS5 more feasible and cost-effective to be adopted as a feed supplement for various livestock industries.
  7. Fulltext Comparative analyses of response surface methodology and artificial neural network on medium optimization for Tetraselmis sp. FTC209 grown under mixotrophic condition
    Mohamed MS, Tan JS, Mohamad R, Mokhtar MN, Ariff AB
    ScientificWorldJournal, 2013;2013:948940.
    PMID: 24109209 DOI: 10.1155/2013/948940
    Mixotrophic metabolism was evaluated as an option to augment the growth and lipid production of marine microalga Tetraselmis sp. FTC 209. In this study, a five-level three-factor central composite design (CCD) was implemented in order to enrich the W-30 algal growth medium. Response surface methodology (RSM) was employed to model the effect of three medium variables, that is, glucose (organic C source), NaNO3 (primary N source), and yeast extract (supplementary N, amino acids, and vitamins) on biomass concentration, X(max), and lipid yield, P(max)/X(max). RSM capability was also weighed against an artificial neural network (ANN) approach for predicting a composition that would result in maximum lipid productivity, Pr(lipid). A quadratic regression from RSM and a Levenberg-Marquardt trained ANN network composed of 10 hidden neurons eventually produced comparable results, albeit ANN formulation was observed to yield higher values of response outputs. Finalized glucose (24.05 g/L), NaNO3 (4.70 g/L), and yeast extract (0.93 g/L) concentration, affected an increase of X(max) to 12.38 g/L and lipid a accumulation of 195.77 mg/g dcw. This contributed to a lipid productivity of 173.11 mg/L per day in the course of two-week cultivation.
  8. Improved mannan-degrading enzymes' production by Aspergillus niger through medium optimization
    Mohamad SN, Ramanan RN, Mohamad R, Ariff AB
    N Biotechnol, 2011 Feb 28;28(2):146-52.
    PMID: 20970530 DOI: 10.1016/j.nbt.2010.10.008
    The effect of different carbon and nitrogen sources on the production of mannan-degrading enzymes, focussing on β-mannanase, by Aspergillus niger was investigated using shake flask culture. The β-mannanase activity obtained during growth of A. niger on guar gum (GG, 1495 nkat mL(-1)) was much higher than those observed on other carbon substrates, locust bean gum (1148 nkat mL(-1)), α-cellulose (10.7 nkat mL(-1)), glucose (8.8 nkat mL(-1)) and carboxymethylcellulose (4.6 nkat mL(-1)). For fermentation using GG as a carbon source, bacteriological peptone gave the highest β-mannanase activity (1744 nkat mL(-1)) followed by peptone from meat (1168 nkat mL(-1)), yeast extract (817 nkat mL(-1)), ammonium sulphate (241 nkat mL(-1)), ammonium nitrate (113 nkat mL(-1)) and ammonium chloride (99 nkat mL(-1)) when used as a nitrogen source. The composition of bacteriological peptone and initial pH of the medium were further optimized using response surface methodology (RSM). Medium consisted of 21.3 g L(-1) GG and 57 g L(-1) peptone with initial culture pH of 5.5 was optimum for β-mannanase production (2063 nkat mL(-1)) by A. niger. The β-mannanase production obtained in this study using A. niger was significantly higher than those reported in the literature.
  9. Improved production of live cells of Lactobacillus rhamnosus by continuous cultivation using glucose-yeast extract medium
    Ling LS, Mohamad R, Rahim RA, Wan HY, Ariff AB
    J Microbiol, 2006 Aug;44(4):439-46.
    PMID: 16953180
    In this study, the growth kinetics of Lactobacillus rhamnosus and lactic acid production in continuous culture were assessed at a range of dilution rates (0.05 h(-1) to 0.40 h(-1)) using a 2 L stirred tank fermenter with a working volume of 600 ml. Unstructured models, predicated on the Monod and Luedeking-Piret equations, were employed to simulate the growth of the bacterium, glucose consumption, and lactic acid production at different dilution rates in continuous cultures. The maximum specific growth rate of L. rhamnosus, mu-max, was estimated at 0.40 h(-1), and the Monod cell growth saturation constant, Ks, at approximately 0.25 g/L. Maximum cell viability (1.3 x 10(10) CFU/ml) was achieved in the dilution rate range of D = 0.28 h(-1) to 0.35 h(-1). Both maximum viable cell yield and productivity were achieved at D = 0.35 h(-1). The continuous cultivation of L. rhamnosus at D = 0.35 h(-1) resulted in substantial improvements in cell productivity, of 267% (viable cell count) that achieved via batch cultivation.
  10. Fulltext Assessment of monacolin in the fermented products using Monascus purpureus FTC5391
    Ajdari Z, Ebrahimpour A, Abdul Manan M, Hamid M, Mohamad R, Ariff AB
    J Biomed Biotechnol, 2011;2011:426168.
    PMID: 22190851 DOI: 10.1155/2011/426168
    Monacolins, as natural statins, form a class of fungal secondary metabolites and act as the specific inhibitors of HMG-CoA reductase. The interest in using the fermented products as the natural source of monacolins, instead of statin drugs, is increasing enormously with its increasing demand. In this study, the fermented products were produced by Monascus purpureus FTC5391 using submerged and solid state fermentations. Two commercial Monascus-fermented products were also evaluated for comparison. Improved methods of monacolins extraction and identification were developed for the assessment of monacolins in the fermented products. Methanol and ethanol were found to be the most favorable solvents for monacolins extraction due to their ability to extract higher amount of monacolin K and higher numbers of monacolin derivatives. Problem related to false-positive results during monacolins identification was solved by adding monacolin lactonization step in the assessment method. Using this improved method, monacolin derivatives were not detected in all Monascus-fermented products tested in this study, suggesting that their hypocholesterolemic effects may be due to other compounds other than monacolins.
  11. Supporting family doctors to address elder abuse: a quasi-experimental study in Malaysia
    Mohd Mydin FH, Othman S, Choo WY, Hairi NNM, Hairi FM, Syed Karim SN, et al.
    J Elder Abuse Negl, 2021 04 25;33(2):151-167.
    PMID: 33899705 DOI: 10.1080/08946566.2021.1919272
    This quasi-experimental study examined the effect of Supporting Family Doctors to Address Elder Abuse (SAFE) educational intervention among family doctors practicing at public primary care clinics in Malaysia. SAFE is an intensive, multimodal, locally tailored, and culturally sensitive face-to-face educational intervention on elder abuse. A significant mean score improvement of knowledge [Baseline: 5.33 (SD:1.33) to 6-month post-intervention: 6.45 (SD: 1.35); p<0.001] and perceived behavioral control [Baseline: 50.83 (SD: 8.87) to six-month post-intervention: 56.16 (SD: 9.56); p<0.001] observed in the intervention group compared to the control group. No significant difference in attitude, subjective norm, and practice scores between the two groups over time. SAFE educational intervention for family doctors was effective to improve but not sustainable knowledge and perceived behavioral control toward elder abuse identification and management. We recommend SAFE educational intervention as part of the continuous medical education for family doctors supplemented with a change in organization and national policy.
  12. Hydrogel beads bio-nanocomposite based on Kappa-Carrageenan and green synthesized silver nanoparticles for biomedical applications
    Azizi S, Mohamad R, Abdul Rahim R, Mohammadinejad R, Bin Ariff A
    Int J Biol Macromol, 2017 Nov;104(Pt A):423-431.
    PMID: 28591593 DOI: 10.1016/j.ijbiomac.2017.06.010
    This paper describes the fabrication and characterization of bio-nanocomposite hydrogel beads based on Kappa-Carrageenan (κ-Carrageenan) and bio-synthesized silver nanoparticles (Ag-NPs). The silver nanoparticles were prepared in aqueous Citrullus colocynthis seed extract as both reducing and capping agent. Cross-linked κ-Carrageenan/Ag-NPs hydrogel beads were prepared using potassium chloride as the cross-linker. The hydrogel beads were characterized using XRD and FESEM. Moreover, swelling property of the hydrogel beads was investigated. The Ag release profile of the hydrogels was obtained by fitting the experimental data to power law equation. The direct visualization of the green synthesized Ag-NPs using TEM shows particle size in the range of 23±2nm. The bio-nanocomposite hydrogels showed lesser swelling behavior in comparison with pure κ-Carrageenan hydrogel. Regardless the slow Ag release, κ-Carrageenan/Ag-NPs presented good antibacterial activities against Staphylococcus aureus, Methicilin Resistant Staphylococcus aurous, Peseudomonas aeruginosa and Escherichia coli with maximum zones of inhibition 11±2mm. Cytotoxicity study showed that the bio-nanocomposite hydrogels with non-toxic effect of concentration below 1000μg/mL have great pharmacological potential and a suitable level of safety for use in the biological systems.
  13. A cluster randomized trial on improving nurses' detection and management of elder abuse and neglect (I-NEED): study protocol
    Loh DA, Choo WY, Hairi NN, Othman S, Mohd Hairi F, Mohd Mydin FH, et al.
    J Adv Nurs, 2015 Nov;71(11):2661-72.
    PMID: 26031344 DOI: 10.1111/jan.12699
    The aim of this study was to describe a trial protocol of an educational intervention for nurses to improve their awareness and practice in detecting and managing elder abuse and neglect.
  14. Mortality among elder abuse victims in rural Malaysia: A two-year population-based descriptive study
    Yunus RM, Hairi NN, Choo WY, Hairi FM, Sooryanarayana R, Ahmad SN, et al.
    J Elder Abuse Negl, 2017;29(1):59-71.
    PMID: 27841737 DOI: 10.1080/08946566.2016.1260083
    Our study aims at describing mortality among reported elder abuse experiences in rural Malaysia. This is a population-based cohort study with a multistage cluster sampling method. Older adults in Kuala Pilah (n = 1,927) were interviewed from November 2013 to May 2014. Mortality was traced after 2 years using the National Registration Department database. Overall, 139 (7.2%) respondents died. Fifteen (9.6%) abuse victims died compared to 124 (7.0%) not abused. Mortality was highest with financial abuse (13%), followed by psychological abuse (10.8%). There was a dose-response relationship between mortality and clustering of abuse: 7%, 7.7%, and 14.0% for no abuse, one type, and two types or more, respectively. Among abuse victims, 40% of deaths had ill-defined causes, 33% were respiratory-related, and 27% had cardiovascular and metabolic origin. Results suggest a link between abuse and mortality. Death proportions varied according to abuse subtypes and gender.
  15. Fulltext Association between elder abuse and poor sleep: A cross-sectional study among rural older Malaysians
    Yunus RM, Wazid SW, Hairi NN, Choo WY, Hairi FM, Sooryanarayana R, et al.
    PLoS One, 2017;12(7):e0180222.
    PMID: 28686603 DOI: 10.1371/journal.pone.0180222
    OBJECTIVES: To examine the association between elder abuse and poor sleep using a Malay validated version of Pittsburgh Sleep Quality Index (PSQI).
    DESIGN: This study was divided into two phases. Phase I tested the construct validity and reliability of the Malay version of PSQI. Phase II was a population-based, cross-sectional study with a multi-stage cluster sampling method. Home-based interviews were conducted by trained personnel using a structured questionnaire, to determine exposure and outcome.
    SETTING: Kuala Pilah, a district in Negeri Sembilan which is one of the fourteen states in Malaysia.
    PARTICIPANTS: 1648 community-dwelling older Malaysians.
    RESULTS: The Malay version of PSQI had significant test re-test reliability with intra-class correlation coefficients of 0.62. Confirmatory factor analyses revealed that one factor PSQI scale with three components (subjective sleep quality, sleep latency, and sleep disturbances) was most suitable. Cronbach's Alpha was 0.60 and composite reliability was 0.63. PSQI scores were highest among neglect (4.11), followed by physical (4.10), psychological (3.96) and financial abuse (3.60). There was a dose-response relationship between clustering of abuse and PSQI scores; 3.41, 3.50 and 3.84 for "no abuse", "1 type of abuse" and "2 types or more". Generalized linear models revealed six variables as significant determinants of sleep quality-abuse, co-morbidities, self-rated health, income, social support and gait speed. Among abuse subtypes, only neglect was significantly associated with poor sleep.
    CONCLUSION: The Malay PSQI was valid and reliable. Abuse was significantly associated with poor sleep. As sleep is essential for health and is a good predictor for mortality among older adults, management of abuse victims should entail sleep assessment. Interventions or treatment modalities which focus on improving sleep quality among abuse victims should be designed.
  16. Fulltext The prevalence and correlates of elder abuse and neglect in a rural community of Negeri Sembilan state: baseline findings from The Malaysian Elder Mistreatment Project (MAESTRO), a population-based survey
    Sooryanarayana R, Choo WY, Hairi NN, Chinna K, Hairi F, Ali ZM, et al.
    BMJ Open, 2017 Sep 01;7(8):e017025.
    PMID: 28864485 DOI: 10.1136/bmjopen-2017-017025
    BACKGROUND: As Malaysia is fast becoming an ageing nation, the health, safety and welfare of elders are major societal concerns. Elder abuse is a phenomenon recognised abroad but less so locally. This paper presents the baseline findings from the Malaysian Elder Mistreatment Project (MAESTRO) study, the first community-based study on elder abuse in Malaysia.

    DESIGN: Cross-sectional study, analysing baseline findings of a cohort of older adults.

    SETTING: Kuala Pilah district, Negeri Sembilan state, Malaysia.

    OBJECTIVES: To determine the prevalence of elder abuse among community dwelling older adults and its associated factors.

    PARTICIPANTS: A total of 2112 community dwelling older adults aged 60 years and above were recruited employing a multistage sampling using the national census.

    PRIMARY AND SECONDARY OUTCOME MEASURES: Elder abuse, measured using a validated instrument derived from previous literature and the modified Conflict Tactic Scales, similar to the Irish national prevalence survey on elder abuse with modification to local context. Factors associated with abuse and profiles of respondents were also examined.

    RESULTS: The prevalence of overall abuse was reported to be 4.5% in the past 12 months. Psychological abuse was most common, followed by financial, physical, neglect and sexual abuse. Two or more occurrences of abusive acts were common, while clustering of various types of abuse was experienced by one-third of abused elders. Being male (adjusted OR (aOR) 2.15, 95% CI 1.23 to 3.78), being at risk of social isolation (aOR 1.96, 95% CI 1.07 to 3.58), a prior history of abuse (aOR 3.28, 95% CI 1.40 to 7.68) and depressive symptomatology (aOR 7.83, 95% CI 2.88 to 21.27) were independently associated with overall abuse.

    CONCLUSION: Elder abuse occurred among one in every 20 elders. The findings on elder abuse indicate the need to enhance elder protection in Malaysia, with both screening of and interventions for elder abuse.

  17. Fulltext Lovastatin in Aspergillus terreus: fermented rice straw extracts interferes with methane production and gene expression in Methanobrevibacter smithii
    Faseleh Jahromi M, Liang JB, Ho YW, Mohamad R, Goh YM, Shokryazdan P, et al.
    Biomed Res Int, 2013;2013:604721.
    PMID: 23710454 DOI: 10.1155/2013/604721
    Lovastatin, a natural byproduct of some fungi, is able to inhibit HMG-CoA (3-hydroxy-3 methyl glutaryl CoA) reductase. This is a key enzyme involved in isoprenoid synthesis and essential for cell membrane formation in methanogenic Archaea. In this paper, experiments were designed to test the hypothesis that lovastatin secreted by Aspergillus terreus in fermented rice straw extracts (FRSE) can inhibit growth and CH4 production in Methanobrevibacter smithii (a test methanogen). By HPLC analysis, 75% of the total lovastatin in FRSE was in the active hydroxyacid form, and in vitro studies confirmed that this had a stronger effect in reducing both growth and CH4 production in M. smithii compared to commercial lovastatin. Transmission electron micrographs revealed distorted morphological divisions of lovastatin- and FRSE-treated M. smithii cells, supporting its role in blocking normal cell membrane synthesis. Real-time PCR confirmed that both commercial lovastatin and FRSE increased (P < 0.01) the expression of HMG-CoA reductase gene (hmg). In addition, expressions of other gene transcripts in M. smithii. with a key involvement in methanogenesis were also affected. Experimental confirmation that CH4 production is inhibited by lovastatin in A. terreus-fermented rice straw paves the way for its evaluation as a feed additive for mitigating CH4 production in ruminants.
  18. Fulltext Optimal path test data generation based on hybrid negative selection algorithm and genetic algorithm
    Mohi-Aldeen SM, Mohamad R, Deris S
    PLoS One, 2020;15(11):e0242812.
    PMID: 33253281 DOI: 10.1371/journal.pone.0242812
    Path testing is the basic approach of white box testing and the main approach to solve it by discovering the particular input data of the searching space to encompass the paths in the software under test. Due to the increasing software complexity, exhaustive testing is impossible and computationally not feasible. The ultimate challenge is to generate suitable test data that maximize the coverage; many approaches have been developed by researchers to accomplish path coverage. The paper suggested a hybrid method (NSA-GA) based on Negative Selection Algorithm (NSA) and Genetic Algorithm (GA) to generate an optimal test data avoiding replication to cover all possible paths. The proposed method modifies the generation of detectors in the generation phase of NSA using GA, as well as, develops a fitness function based on the paths' prioritization. Different benchmark programs with different data types have been used. The results show that the hybrid method improved the coverage percentage of the programs' paths, even for complicated paths and its ability to minimize the generated number of test data and enhance the efficiency even with the increased input range of different data types used. This method improves the effectiveness and efficiency of test data generation and maximizes search space area, increasing percentage of path coverage while preventing redundant data.
  19. Fulltext Optimisation and Characterisation of Lipase-Catalysed Synthesis of a Kojic Monooleate Ester in a Solvent-Free System by Response Surface Methodology
    Jumbri K, Al-Haniff Rozy MF, Ashari SE, Mohamad R, Basri M, Fard Masoumi HR
    PLoS One, 2015;10(12):e0144664.
    PMID: 26657030 DOI: 10.1371/journal.pone.0144664
    Kojic acid is widely used to inhibit the browning effect of tyrosinase in cosmetic and food industries. In this work, synthesis of kojic monooleate ester (KMO) was carried out using lipase-catalysed esterification of kojic acid and oleic acid in a solvent-free system. Response Surface Methodology (RSM) based on central composite rotatable design (CCRD) was used to optimise the main important reaction variables, such as enzyme amount, reaction temperature, substrate molar ratio, and reaction time along with immobilised lipase from Candida Antarctica (Novozym 435) as a biocatalyst. The RSM data indicated that the reaction temperature was less significant in comparison to other factors for the production of a KMO ester. By using this statistical analysis, a quadratic model was developed in order to correlate the preparation variable to the response (reaction yield). The optimum conditions for the enzymatic synthesis of KMO were as follows: an enzyme amount of 2.0 wt%, reaction temperature of 83.69°C, substrate molar ratio of 1:2.37 (mmole kojic acid:oleic acid) and a reaction time of 300.0 min. Under these conditions, the actual yield percentage obtained was 42.09%, which is comparably well with the maximum predicted value of 44.46%. Under the optimal conditions, Novozym 435 could be reused for 5 cycles for KMO production percentage yield of at least 40%. The results demonstrated that statistical analysis using RSM can be used efficiently to optimise the production of a KMO ester. Moreover, the optimum conditions obtained can be applied to scale-up the process and minimise the cost.
  20. Strategies for improvement of gamma-aminobutyric acid (GABA) biosynthesis via lactic acid bacteria (LAB) fermentation
    Pannerchelvan S, Rios-Solis L, Faizal Wong FW, Zaidan UH, Wasoh H, Mohamed MS, et al.
    Food Funct, 2023 Mar 23.
    PMID: 36951915 DOI: 10.1039/d2fo03936b
    Gamma-aminobutyric acid (GABA) is a non-protein amino acid widely distributed in nature and extensively explored for its numerous physiological functions and effects on metabolic disorders. Lactic acid bacteria (LAB) are one of the most important GABA producers, vigorously pursued due to their high GABA content and generally regarded as safe (GRAS) status that allows for direct formulation in various GABA-enriched food products. To meet the strict requirements of the food and nutraceutical industries, the biosynthesis of GABA is typically preferred over the chemical synthesis route. The production of GABA varies among various strains of LAB and is affected by different fermentation conditions. Hence, optimizing the fermentation conditions to enhance the activity of the key enzyme glutamic acid decarboxylase is essential to maximize GABA production. This paper reviews the beneficial effects of GABA on human health and its applications in fermented food products. A particular emphasis is given to the biosynthetic approach for producing GABA by various LAB species via the microbial fermentation route. Efficient strategies for enhancing GABA production through optimization of the fermentation conditions, mode of fermentation, two-step fermentation, co-culturing approach, immobilization technique and genetic engineering are discussed in detail.
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