Browse publications by year: 2016

  1. Chan Kg, Yap Ac, Choo Ym
    Sains Malaysiana, 2016;45:1073-1077.
    Burkholderia cenocepacia and Serratia marcescens are Gram-negative proteobacteria commonly found in the natural
    environment and are also opportunistic pathogens that caused a number of human diseases. The fermentation culture of
    Burkholderia cenocepacia yielded three compounds, 4-(2-hydroxyethoxy)-phenol (1), Maculosin (2) and methyl myristate
    (3). Compound 2 was also isolated together with cyclo(L-Leu-L-Pro) (4) from Serratia marcescens. Compound 1 was
    isolated from a natural source for the first time and the first isolation of compounds 2-4 was also reported from both
    Burkholderia cenocepacia and Serratia marcescens.
    MeSH terms: Environment; Fermentation; Humans; Myristates; Peptides, Cyclic; Phenols; Piperazines; Serratia marcescens; Phenol; Myristic Acid; Proteobacteria; Burkholderia cenocepacia
  2. Ling Onn M, Teen Lim P, Aazani Mujahid, Proksch P, Müller M
    Sains Malaysiana, 2016;45:1063-1071.
    Endophytic fungi provide protection to their host plant and the fungi often produce antimicrobial compounds to aid the host
    fighting off pathogens. These bioactive compounds were secondary metabolites which were often produced as waste- or
    by-products. In the present study, endophytic fungi isolated from mangrove plants and soils were characterized and their
    antimicrobial production and bioremediation potential of heavy metals copper (Cu) and zinc (Zn) were assessed. Twelve
    (12) isolated and identified endophytic fungi belonged to seven species; Penicillium, Curvularia, Diaporthe, Aspergillus,
    Guignardia, Neusartorya and Eupenicillium. Antimicrobial activities of these 12 fungal endophytes were tested against
    Gram negative bacteria; Bacillus subtilis, Staphylococcus aureus, Gram positive bacteria; Escherichia coli and fungi;
    Candida albicans and Aspergillus niger among others. Two isolates (related to Guignardia sp. and Neusartoya sp.) showed
    strong antimicrobial (and antifungal) activity whereas the rest showed no activity. Compounds were isolated from both
    isolates and screened using HPLC. Both isolates displayed chemically very interesting chromatograms as they possessed a
    high diversity of basic chemical structures and peaks over a wide range of polarities, with structures similar to Trimeric
    catechin and Helenalin among others. For bioremediation assessment, the results showed maximum biosorption capacity
    for two isolates related to Curvularia sp. and Neusartorya sp., with the former removing 25 mg Cu/g biomass and the
    latter removing 24 mg Zn/g biomass. Our results indicated the potential of mangrove endophytic fungi in producing
    bioactive compounds and also highlighted their potential for the treatment of heavy metal-contaminated wastewater.
    MeSH terms: Anti-Infective Agents; Anti-Bacterial Agents; Antifungal Agents; Aspergillus niger; Bacillus subtilis; Biodegradation, Environmental; Candida albicans; Catechin; Chromatography, High Pressure Liquid; Copper; Escherichia coli; Penicillium; Sesquiterpenes; Soil; Staphylococcus aureus; Zinc; Biomass; Eupenicillium; Endophytes; Waste Water
  3. Wan Haizatul Akmal Che Yusoff, Zazali Alias, Khanom Simarani
    Sains Malaysiana, 2016;45:1057-1062.
    The glutathione S-Transferase (GST) enzyme plays an important role in cellular detoxification. This multifunctional enzyme
    is involved in Phase II detoxification pathways that protect cellular macromolecules from being attacked by harmful
    compound. The study is an attempt to isolate glutathione transferase-expressing bacteria from the rhizospheric soil of
    selected herbal plants. Screening showed nine positive isolates out of twelve bacterial samples from a large microbial
    population in our soil collection. Crude extract from strain E1 which was isolated from Piper sarmentosum (Kadok)
    showed the highest specific activity against 1-chloro-2, 4-dinitrobenzene substrates (5.78 × 10-06 µmol/min/mg). Based
    on the carbon utilization of E1 assessed using Biolog system, the strain was identified as Comamonas testosterone E1.
    Glutathione S-transferase purification using GST trap yielded two distinct subunits with molecular weights of 23 and 24
    kDa as visualized on 1D SDS-polyacrylamide gel electrophoresis. The purified GST showed reactivity towards 1-chloro-2,
    4-dinitrobenzene, 1, 2-dichloro-4-nitrobenzene and ethacrynic acid with specific activity of 0.264 ± 0.038 nmol/min/
    mg and 0.056 ± 0.002 nmol/min/mg and 10.500 ± 3.130 nmol/min/mg, respectively. However, no activity was detected
    against p-Nitrobenzyl chloride, Sulfobromophthalein, trans-4-phenyl-3-butene-2-one, hexa-2, 4- dienal, trans-hepta-2,
    4-dienal and trans-oct-2-enal in the study.
  4. Ouled-haddar H, Sifour M, Idoui T, Bouridane H, Arid S
    Sains Malaysiana, 2016;45:1049-1055.
    A Lactobacillus plantarum strain G1 was previously isolated from chicken crop and it was found to show interesting
    probiotic properties. In this study, several microencapsulation combined materials were used to test their ability to protect
    cells from gastrointestinal harsh conditions. The results on kinetics of cell release after exposition to acidic pH (2.0)
    indicated that the efficiency of cell entrapment of the gels was as follows starting from the highest capacity to the lowest
    one: sodium alginate, alginate-agar (AA), alginate-starch (AS) and κ-carrageenan. In addition, effect of bile salts on
    cell release was also tested; the results showed that the efficiency of entrapment of the gels was different and as follows
    starting from the highest capacity to the lowest one: AA, sodium alginate, κ-carrageenan, and AS. Moreover, viability of
    free and alginate-microencapsulated Lactobacillus plantarum after exposure to acid, bile and pancreatic enzymes was
    investigated; the results showed that microencapsulation was capable of protecting cells against the harsh conditions of
    the gastrointestinal tract. In addition, microencapsulation enhanced the viability of Lb. plantarum during cold storage
    for 2 weeks and during a range of heat treatments.
  5. Jiang L, Yue K, Yang Y, Wu Q
    Sains Malaysiana, 2016;45:1041-1047.
    Litter decomposition is vital for carbon and nutrient turnover in terrestrial ecosystems, and this process has now
    been thoroughly demonstrated to be regulated by various mechanisms. The total environment has been continuously
    changing in recent decades, especially in high-latitude regions; these alterations, however, profoundly contribute to the
    decomposition process, but a comprehensive recognition has not available. Here we reviewed the empirical observations
    and current knowledge regarding how hydrological leaching and freeze-thaw events modulate early decomposition of
    plant litter. Leaching contributes a considerable percentage of mass loss and carbon and nutrient release in early stage of
    decomposition, but the magnitudes are different between species levels depending on the chemical traits. Frequent freezing
    and thawing events could positively influence decomposition rate in cold biomes but also hamper soil decomposer and
    there is no general and predictable pattern has been emerged. Further experiments should be manipulated to estimate
    how the altered freezing and thawing effect on carbon and nutrient release from plant litter to better understanding the
    changing environment on litter decomposition.
    MeSH terms: Carbon; Environment; Freezing; Plants; Soil; Ecosystem; Hydrology
  6. Norhayati Y, Wahizatul Afzan A, Siti Noor Jannah S, Nurul Wahidah MR
    Sains Malaysiana, 2016;45:1035-1040.
    Interaction between the Red Palm Weevil (RPW) and coconuts will stimulate the plants’ early response by producing the
    reactive oxygen species (ROS) which causes lipid peroxidation and membrane damage of the host plants. Thus, a multiple
    defense lines, including both scavenging enzymes and molecular antioxidants have been evolved to promptly inactivate
    these radicals. This study investigated the responses of catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX),
    α-tocopherol, ascorbic acid and carotenoids contents of three coconut cultivars which were PANDAN, MAWA and MATAG
    against the RPW infestation. The infested PANDAN and MAWA exhibited higher CAT, POD and APX specific activities of 2.60
    ± 0.11, 5.0 ± 0.72 and 1.58 ± 0.20 units/mg protein for PANDAN whereas 1.13 ± 0.04, 39.38 ± 2.29 and 1.15 ± 0.16 units/
    mg, protein for MAWA) compared with controls. However, MATAG cultivar showed no significant difference (p<0.05) in the
    production of both enzymes except for POD specific activities. RPW infestations only managed to trigger the α-tocopherol
    concentrations in the MAWA cultivar compared with the others. Infested MAWA and MATAG increased the ascorbic acid
    concentrations, however, a contrast results was observed in infested PANDAN. All coconut cultivars exhibited higher
    carotenoids content (2771.20 ± 263.90, 3043.20 ± 526.35 and 921.20 ± 281.10 µg/g.fwt of PANDAN, MAWA and MATAG,
    respectively) compared with their respective controls (455.20 ± 135.10, 1408.40 ± 103.02 and 248.80 ± 110.39 µg/g.
    fwt). The above results indicated that the oxidative stress induced by the RPW infestation would stimulate the activities of
    enzymes and molecular antioxidants studied especially in infested MAWA. Thus, it may be suggested that MAWA cultivar
    was more tolerance towards RPW infestation compared to MATAG and PANDAN. It is hoped that this finding will provide
    clues on how plant respond toward stress during infestation, thus further action can be activated as soon as possible to
    control the spread of R. ferrugineus.
  7. Razieh Shojanoori, Helmi Z.m. Shafri, Shattri Mansor, Mohd Hasmadi Ismail
    Sains Malaysiana, 2016;45:1025-1034.
    The growth of residential and commercial areas threatens vegetation and ecosystems. Thus, an urgent urban management
    issue involves determining the state and the quantity of urban tree species to protect the environment, as well as controlling
    their growth and decline. This study focused on the detection of urban tree species by considering three types of tree
    species, namely, Mesua ferrea L., Samanea saman, and Casuarina sumatrana. New rule sets were developed to detect these
    three species. In this regard, two pixel-based classification methods were applied and compared; namely, the method of
    maximum likelihood classification and support vector machines. These methods were then compared with object-based
    image analysis (OBIA) classification. OBIA was used to develop rule sets by extracting spatial, spectral, textural and color
    attributes, among others. Finally, the new rule sets were implemented into WorldView-2 imagery. The results indicated
    that the OBIA based on the rule sets displayed a significant potential to detect different tree species with high accuracy.
    MeSH terms: Biological Phenomena; Environment; Trees; Ecosystem; Protective Agents; Support Vector Machine
  8. Zaleha K, Nasiratul_shahida MN, Siang HY, Kamaruzzaman BY
    Sains Malaysiana, 2016;45:1019-1024.
    Meiobenthos in Bidong Archipelago in coastal water of the South China Sea is hypothesised to have a certain trend of
    distribution particularly in the island ecosystem where it is usually having different type of sea bottom. Nonetheless, since
    it is located in a tropical area, the trend at the sub-tidal could be less obvious due to absent of clear season. Meiobenthic
    sampling was carried out in Karah Island, an island in Bidong Archipelago, from the intertidal, towards the sub-tidal
    zone covering the coral and non-coral area to see the trend in the density and composition. A transparent hand core
    was used to collect benthos samples. Nematoda and harpacticoid copepods dominated the intertidal and sub-tidal zone
    respectively. Harpacticoid copepods were higher in density in the non-coral sediment than the coral area. This could be
    due to the high content of silt and clay in the coral area (2.98% of silt and clay). The 2-dimension MDS analysis on the
    density data indicated the highest degree of scattering and an over-lapping condition for those intertidal and sub-tidal
    samples respectively. ANOSIM result showed that the degree of similarity was lower at the intertidal (70%) than the subtidal
    (reaching 90%) in the first sampling before both became no significant different in the second sampling. It could
    indicate the stable condition in the subtidal than the intertidal ecosystem. The comparatively low density of meiobenthos
    could indicate their response towards the environmental condition in the area which will only be confirmed by long term
    ecological study.
    MeSH terms: Aluminum Silicates; Animals; China; Nematoda; Seasons; Ecosystem; Copepoda; Anthozoa; Islands
  9. Irshad M, Ullah F, Mehmood S, Khan AU
    Sains Malaysiana, 2016;45:1013-1018.
    Allelopathy is a process in which one plant species may usefully or adversely affect the growth of other plant species
    through the production of allelochemicals. During the present investigation, mulch effect of Jatropha curcas leaves was
    evaluated on seed germination and seedling growth of maize varieties viz. Pioneer (V1), Azam (V2) and Jalal (V3). Mulch
    was applied at 1 and 2 tons/hectare. Phenolic compounds were detected in Jatropha curcas leaf (131.15 mg gallic acid
    eq./gm extract). Mulch applied at 2 tons/hectare significantly reduced seed germination (%), germination index, relative
    water content, root width and seedling dry weight. From the findings of the present investigation, it was inferred that
    Jatropha curcas leaves exhibited phytotoxic effects on maize at high concentrations.
    MeSH terms: Biological Phenomena; Zea mays; Gallic Acid; Phenols; Pheromones; Seeds; Water; Plant Leaves; Plant Roots; Germination; Jatropha; Seedlings; Allelopathy
  10. Osama Ala’yed, Ying TY, Azizan Saaban
    Sains Malaysiana, 2016;45:1007-1012.
    In this article, a fourth order quintic spline method has been developed to obtain numerical solutions for second order
    boundary value problems with Dirichlet boundary conditions. The developments of the quintic spline method and
    convergence analysis were presented. Three test problems have been considered for comparison purposes. The numerical
    results showed that the quintic spline method is more accurate compared to existing cubic spline method when solving
    nonlinear second order boundary value problems but vice versa when solving linear second order boundary value
    MeSH terms: Algorithms; Models, Theoretical
  11. Zaharuzaman Jamaluddin, Ahmad Mahir Razali, Zainol Mustafa, Mohd Rashid Ab Hamid
    Sains Malaysiana, 2016;45:999-1006.
    The aim of this article was to validate an instrument of quality management practices (QMPs) and performance
    measurement for the manufacturing industry in Malaysia. QMPs and performance were measured using the following
    six value indicators: Management commitment, training, process management, quality tools, continuous improvement
    and organisational performance. A total of 480 questionnaires were distributed and 210 questionnaires were valid for
    analysis. A confirmatory factor analysis (CFA) approach was employed using analysis of moment structures (AMOS)
    software. The results for the hypothesised CFA model showed the following fit statistics: Comparative fit index (CFI) =
    0.924, Tucker Lewis index (TLI) = 0.913 and root mean square error of approximation (RMSEA) = 0.061. The values of
    CFI and TLI ≥ 0.9 and at the same time the value of RMSEA ≤ 0.08 showed that CFA model fits the data very well. Hence,
    the results of the study can be used by managers in manufacturing companies to consider and adapt their QMPs and
    performance assessments toward increasing competitiveness
  12. Iskandar Shah Mohd Zawawi, Zarina Bibi Ibrahim
    Sains Malaysiana, 2016;45:989-998.
    In this paper, the fully implicit 2-point block backward differentiation formula and diagonally implicit 2-point block
    backward differentiation formula were developed under the interpretation of generalized differentiability concept for
    solving first order fuzzy differential equations. Some fuzzy initial value problems were tested in order to demonstrate the
    performance of the developed methods. The approximated solutions for both methods were in good agreement with the
    exact solutions. The numerical results showed that the diagonally implicit method outperforms the fully implicit method
    in term of accuracy.
    MeSH terms: Algorithms; Cell Differentiation; Numerical Analysis, Computer-Assisted
  13. Aziz AM, Omar MZ, Salleh MS
    Sains Malaysiana, 2016;45:977-987.
    Pemprosesan logam separa pepejal yang juga dikenali sebagai pembentukan-tikso merupakan suatu kaedah pemprosesan
    yang secara relatifnya adalah baharu jika dibandingkan dengan kaedah pemprosesan biasa seperti penuangan dan
    penempaan. Sebelum pembentukan-tikso dapat dilakukan, aloi berkenaan perlu melalui langkah awal persediaan iaitu
    dengan mengubah mikrostruktur asal berbentuk dendritik kepada bentuk hampir sfera. Ini diikuti dengan pemanasan
    semula ke julat suhu separa pejal (iaitu sekitar 30-50% cecair) dan seterusnya proses ubah bentuk ke dalam acuan
    menggunakan mesin penekanan hidraulik. Antara kaedah utama yang biasa digunakan bagi penyediaan bahan aloi
    ini adalah tuangan cerun penyejukan, pengadukan mekanik dan kaedah terma langsung. Kajian ini memberi tumpuan
    kepada evolusi mikrostruktur aloi aluminium A333 (Al-7.5Si-3.1Cu) daripada bentuk dendritik kepada hampir sfera
    sebagai persediaan untuk diproses melalui pembentukan-tikso kelak. Kaedah tuangan cerun penyejukan digunakan
    dalam kajian ini kerana kaedah ini diketahui berkesan tapi mudah digunakan. Nilai saiz ira dan faktor bentuk dianalisis
    berdasarkan kepada suhu tuangan dan panjang cerun penyejukan berbeza yang digunakan. Di samping itu, kaedah
    kalometri pengimbas perbezaan juga diguna pakai dalam mengenal pasti suhu sempadan pepejal dan sempadan cecair
    aloi ini. Saiz ira fasa pepejal α-Al paling kecil dan nilai faktor bentuk terbaik yang diperoleh dalam kajian ini berlaku
    pada suhu tuangan 620°C dan panjang cerun 300 mm, iaitu masing-masing pada 15.3 µm dan 0.54.
  14. Hazwan Halimoon, Abdul Rashid Hussain, Kouzani A, Muhd Nazrul Hisham Zainal Alam
    Sains Malaysiana, 2016;45:969-976.
    In this paper, a minibioreactor platform made of low cost polymers is presented. The minibioreactor prototype was designed
    as an alternative solution for carrying out microbial fermentation experiments in laboratory. The minibioreactor prototype
    has a working volume of 1.5 mL and was fabricated from poly(methylmethacrylate) (PMMA) and poly(dimethylsiloxane)
    (PDMS) polymers. Cell density was measured online whilst agitation rates and the temperature of the reactor content
    can be tightly controlled to desired set-point values. As proof-of-concept, various S. cerevisae fermentation experiments
    were conducted. In every experiment, the minibioreactor operated stably for the entire length of operation which was
    nearly 40 h with very minimal volume loss i.e. about 2.8 µL·h-1 at 37ºC. The minibioreactor has the maximum oxygen
    transfer rate (OTR) of 16.6 mmol·L-1·h-1 under the agitation rate of 300 rpm. Under these conditions, cell specific growth
    rate as high as 0.291 h-1 was obtained. The experimental data in the minibioreactor operation was also reproducible
    using shake flask where similar growth profiles were attained under a similar growth conditions.
  15. Chuah TS, Norhafizah MZ, Naimah AH, Ismail BS
    Sains Malaysiana, 2016;45:963-967.
    The allelochemical 2,4-di-tert-butylphenol (2,4-DTBP) is one of the natural compounds present in medicinal plants.
    This compound has been reported to possess herbicidal properties. However, its effect on weed growth parameters is
    unknown for it to be utilized in weed management. Hence, the herbicidal potential of the allelochemical 2,4-DTBP on the
    root and leaf tissues of the grassy weed, Leptochloa chinensis (L.) Nees and the broadleaf weed, Hedyotis verticillata
    (L.) Lam was investigated. After 2,4-DTBP treatment, both bioassay species had abnormal and much shorter root hairs
    compared to those of untreated plants. The roots of H. verticillata were severely damaged with the root nodes turned
    brown. The phytotoxic effect of 2,4-DTBP on L. chinensis and H. verticillata became apparent at seven days and 14 days
    after treatment with symptoms of lamina wilting and necrosis, respectively. These results demonstrated that 2,4-DTBP
    could be used as a natural herbicide for the control of L. chinensis and H. verticillata.
    MeSH terms: Biological Assay; Poaceae; Hair; Herbicides; Phenols; Pheromones; Plants, Medicinal; Hedyotis
  16. Soontornchaiboon W, Kim SM, Pawongrat R
    Sains Malaysiana, 2016;45:955-962.
    The effects of six pretreatments of five agricultural wastes (corn cob, pineapple waste, bagasse, rice straw and water
    hyacinth) on the chemical composition and total reducing sugar yield were investigated. Six pretreatments were: 1% NaOH
    with ultrasound for 60 min; 1% NaOH with ultrasound 100% duty; 2% NaOH with ultrasound for 60 min; 2% NaOH
    with ultrasound 100% duty cycle; 1% NaOH by standing in the oven at 60°C for 90 min; and 2% NaOH by standing
    in the oven at 60°C for 90 min. Among them, the highest cellulose content of 55.15% was obtained from bagasse by
    pretreating with 1% NaOH with ultrasound 100% duty cycle. It subsequently yielded the highest total reducing sugar of
    36.21% (36.21 g reducing sugar/100 g substrate). The lignin content of all samples significantly decreased, but ultrasonic
    pretreatment increased the cellulose content. However, the best pretreatment method for each sample was different. Based
    on SEM analysis, the morphologies of all samples were changed after pretreatment. In addition, the increase of enzyme
    loading from 250 to 550 CMC U/g biomass led to more than 20% increase in the total reducing sugar. It was found that
    the higher enzyme loading (700 CMC U/g dried biomass) did not improve the total reducing sugar for all samples.
  17. Siti Afida I., Razmah G., Zulina A. M.
    Sains Malaysiana, 2016;45:949-954.
    The concern on the widespread use of surfactants is increasing worldwide as they can be potential toxicants by polluting
    the environment, with the damage formed depending on their exposure and persistence in the ecosystem. This paper
    was intended to evaluate the biodegradability of palm-based surfactant, MES, in order to establish their environmental
    friendliness. The respirometric method was used to monitor the biodegradation of various homologues of MES over 28
    days as described in the OECD 301F Manometric respirometry test method. The results showed all the MES homologues
    tested were readily biodegradable with percentage of biodegradation achieved for C12, C14 and C16 MES was 73%
    within 6 days, 66% within 8 days and 63% within 16 days, respectively, while linear alkylbenzene sulphonates (LAS)
    sample 60% biodegraded within 8 days. From the results, it can be concluded that the longer the carbon chain length, the
    lower is the biodegradability of MES as the microorganisms took longer time to degrade a longer chain surfactant. Other
    than that, the presence of aromatic structure in LAS may also extend the biodegradation process. The use of palm-based
    surfactant, i.e. MES, is more environmental friendly and can be used as an alternative to petroleum-based surfactant to
    reduce adverse environmental effects of surfactant on ecosystem.
    MeSH terms: Biodegradation, Environmental; Carbon; Petroleum; Surface-Active Agents; Alkanesulfonic Acids; Ecosystem; Organisation for Economic Co-Operation and Development
  18. Cheong AT, Lee PY, Ng CJ, Lee YK, Ong TA, Abdullah KL, et al.
    Sains Malaysiana, 2016;45:941-947.
    There are many treatment options for localized prostate cancer, and there is clinical equipoise in relation to the treatment outcomes. This study aimed to explore doctors’ approaches to decision support in counseling patients with localized prostate cancer in a country with a less established system of support and care delivery for cancer treatment. Four in-depth
    interviews and three focus group discussions were conducted with seven government policy makers/consultant urologists, three oncologists, four private urologists and six urology trainees in Malaysia between 2012 and 2013. Doctors facilitated the treatment decision by explaining about the disease and the treatment options, which included monitoring,
    side effects and complications of each treatment option. Paper-based (charts and diagram drawings) or electronic (ipad apps and websites) illustrations and physical models were used as patient education aids. Further reading materials and websites links were often provided to patients. Patients were given time till subsequent follow up to decide on the
    treatment and family involvement was encouraged. Referral to other healthcare professionals (oncologist, radiotherapist or other urologist) for second opinion was offered to the patients. The doctors would recommend patients to speak to prostate cancer survivors for peer support but official support groups were not easily accessible. This study highlighted
    a multi-faceted approach to support patients with localized prostate cancer in making a treatment decision. It not only involved the doctors (urologist or oncologist) themselves, but also empowered the patients and their social network to support the decision making process.
    MeSH terms: Adult; Health Personnel; Hospitals; Humans; Malaysia; Prostatic Neoplasms*; Interview; Qualitative Research; Urologists*
  19. Roh JM, Lee JH, Lee SS, Bahk JD, Kim TW, Kim Is, et al.
    Sains Malaysiana, 2016;45:933-940.
    Salmonella typhimurium MMP13 harboring pMMP99, a recombinant plasmid derived by cloning a ghost cassette into
    T-vector, were employed for production of ghost cells. Growth of MMP13 (pMMP99) showed an initial increase after a
    shift in temperature from 28 to 42°C, and then decreased gradually with ghost formation being complete within 3 h.
    Ghost yield of MMP13 (pMMP99) were 99.99% less than 104 CFU/mL. MMP13 (pMMP101-1) showed a ghost yield similar
    to MMP13 (pMMP99). Immune responses of BALB/c mice against ghost cells originated from MMP13 (pMMP101-1) were
    assessed by measuring total IgG, IgG1, IgG2a, and secretory IgA levels in each sample. Levels of total IgG, IgG1 and
    IgG2a and vaginal IgA, increased abruptly after 4 weeks post vaccination, whereas the fecal IgA level did not induce
    significant change. Splenocyte proliferation was observed at the cellular level owing to stimulation of ghost cells. Ghost
    vaccination protected 25-59% of mice against wild-type S. typhimurium more than those of controls.
  20. Kuek FWI, Aazani Mujahid, Lim Pt, Leaw Cp, Müller M
    Sains Malaysiana, 2016;45:915-931.
    Little is known about the diversity and roles of microbial communities in the South China Sea, especially the eastern
    region. This study aimed to expand our knowledge on the diversity of these communities in Malaysian waters, as well as
    their potential involvement in the breakdown or osmoregulation of dimethylsulphoniopropionate (DMSP). Water samples
    were collected during local cruises (Kuching, Kota Kinabalu, and Semporna) from the SHIVA expedition and the diversity
    of bacterial communities were analysed through the isolation and identification of 176 strains of cultured bacteria. The
    bacteria were further screened for the existence of two key genes (dmdA, dddP) which were involved in competing,
    enzymatically-mediated DMSP degradation pathways. The composition of bacterial communities in the three areas varied
    and changes were mirrored in physico-chemical parameters. Riverine input was highest in Kuching, which was mirrored
    by dominance of potentially pathogenic Vibrio sp., whereas the Kota Kinabalu community was more indicative of an
    open ocean environment. Isolates obtained from Kota Kinabalu and Semporna showed that the communities in these
    areas have potential roles in bioremediation, nitrogen fixing and sulphate reduction. Bacteria isolated from Kuching
    displayed the highest abundance (44%) of both DMSP-degrading genes, while the bacterial community in Kota Kinabalu
    had the highest percentage (28%) of dmdA gene occurrence and the dddP gene responsible for DMS production was
    most abundant (33%) within the community in Semporna. To the best of our knowledge, this is the first study looking at
    the diversity of culturable bacteria in coastal waters of East Malaysia and also their potential roles in the DMS(P) cycle.
    MeSH terms: Biodegradation, Environmental; China; Expeditions; Malaysia; Nitrogen; Oceans and Seas; Sulfates; Sulfonium Compounds; Vibrio; Osmoregulation
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