Browsing by Author "Marasri Ruengjitchatchawalya"

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    Cadmium removal by immobilized scytonema sp. and hapalosiphon hibernicus
    (2006-12-01) Sudarat Chaichalearm; Duangrat Inthorn; Marasri Ruengjitchatchawalya; Prayad Pokethitiyook; Mahidol University; King Mongkuts University of Technology Thonburi
    Cadmium removal from aqueous solution (1 mg/l) was investigated in Scytonema sp. and Hapalosiphon hibernicus on eight types of immobilized material as loofa sponge(LS), delicate duty scour pad (DP), synthetic fiber (SF), polyethylene terepthalate (PET), polyethylene terepthalate (PET non-woven fabric), polyethylene (PE), polypropylene (PP) and polyurethane (PU). The results showed that immobilized cells on SF and free cells of Scytonema sp. and Hapalosiphon hibernicus had high cadmium removal rates at 93%, 95% and 85%, 98%, respectively. Immobilizing ability and dry weight per surface area (DW/SA) were 96%, 0.003 g cell/ cm3 and 97%, 0.0023 g cell/cm3 for Scytonema sp. immobilized on PET and Hapalosiphon hibernicus immobilized on SF, respectively. Immobilized cells on SF and PET, and free cells of Scytonema sp. had maximum adsorption capacities (qmax) at 26.74, 37.74 and 31.95 mg/g dry wt. and binding constants (kb) at 6.45, 2.14 and 2.70 l/mg, respectively when R2>0.96, while immobilized cells on SF and PET, and free cells of Hapalosiphon hibernicus had qmax values at 57.80, 64.52 and 59.17 mg/g dry wt. and kb values at 1.57, 2.07 and 1.50 l/mg. respectively when R2>0.99. The ultra-structural changes of both strains exposed to 1 mg/l of cadmium were observed under a transmission electron microscope. Cells were damaged and convoluted in the cell surface and intra-cellular organelles. Electron dense particles deposited in the cell walls and internal organelles of Hapalosiphon hibernicus indicated that cadmium uptake was probably by adsorption mechanism in cell membranes and accumulated in the intra-cellular organelles. Immobilized cells of Scytonema sp. and H. hibernicus on SF and PET have the potential to remove cadmium in wide spread low cadmium contaminated natural water such as in rivers or channels and can be applied in shrimp ponds. Copyright © Enviromedia.
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    Higher plant-like fluorescence induction and thermoluminescence characteristics in cyanobacterium, Spirulina mutant defective in PQH<inf>2</inf> oxidation by cytb<inf>6</inf>/f complex
    (2005-10-14) Marasri Ruengjitchatchawalya; László Kovács; Tipawan Mapaisansup; Anna Sallai; Zoltán Gombos; Mathurose Ponglikitmongkol; Morakot Tanticharoen; King Mongkuts University of Technology Thonburi; Biological Research Center at Hungarian Academy of Sciences; Mahidol University; Thailand National Center for Genetic Engineering and Biotechnology
    Characterization of the photosynthetic electron transport in a mutant of Spirulina platensis, generated by chemical mutagenesis, demonstrated that the electron transfer from the plastoquinone (PQ) to cytochrome b6/f was slowed. Thermoluminescence (TL) measurements suggested the presence of reversed energy flow via PQ, which resulted in an emergence of the plant-like after-glow TL band at 45°C that could be enhanced by the transthylakoidal pH gradient and could be eliminated by an uncoupler, FCCP. The localization of the changes in the electron transport of the mutant cells measured by various methods revealed that the re-oxidation of the PQ pool is hampered in the mutant compared to the wild-type cells. The reduction in energy migration was localized between PQ and PS I reaction centers. © 2005 Elsevier GmbH. All rights reserved.
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    Immunodominant linear B cell epitopes in the spike and membrane proteins of SARS-CoV-2 identified by immunoinformatics prediction and immunoassay
    (2021-12-01) Kanokporn Polyiam; Waranyoo Phoolcharoen; Namphueng Butkhot; Chanya Srisaowakarn; Arunee Thitithanyanont; Prasert Auewarakul; Tawatchai Hoonsuwan; Marasri Ruengjitchatchawalya; Phenjun Mekvichitsaeng; Yaowaluck Maprang Roshorm; Siriraj Hospital; Chulalongkorn University; Mahidol University; King Mongkut's University of Technology Thonburi; B.F. Feed Company Limited
    SARS-CoV-2 continues to infect an ever-expanding number of people, resulting in an increase in the number of deaths globally. With the emergence of new variants, there is a corresponding decrease in the currently available vaccine efficacy, highlighting the need for greater insights into the viral epitope profile for both vaccine design and assessment. In this study, three immunodominant linear B cell epitopes in the SARS-CoV-2 spike receptor-binding domain (RBD) were identified by immunoinformatics prediction, and confirmed by ELISA with sera from Macaca fascicularis vaccinated with a SARS-CoV-2 RBD subunit vaccine. Further immunoinformatics analyses of these three epitopes gave rise to a method of linear B cell epitope prediction and selection. B cell epitopes in the spike (S), membrane (M), and envelope (E) proteins were subsequently predicted and confirmed using convalescent sera from COVID-19 infected patients. Immunodominant epitopes were identified in three regions of the S2 domain, one region at the S1/S2 cleavage site and one region at the C-terminus of the M protein. Epitope mapping revealed that most of the amino acid changes found in variants of concern are located within B cell epitopes in the NTD, RBD, and S1/S2 cleavage site. This work provides insights into B cell epitopes of SARS-CoV-2 as well as immunoinformatics methods for B cell epitope prediction, which will improve and enhance SARS-CoV-2 vaccine development against emergent variants.
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    Study of the structural pathology caused by CYP2C9 polymorphisms towards flurbiprofen metabolism using molecular dynamics simulation
    (2010-12-06) Yuranat Saikatikorn; Panida Lertkiatmongkol; Anunchai Assawamakin; Marasri Ruengjitchatchawalya; Sissades Tongsima; King Mongkuts University of Technology Thonburi; Mahidol University; National Center for Genetic Engineering and Biotechnology (BIOTEC
    CYP2C9 is one of the major cytochrome P450 enzymes that play a crucial role in metabolic clearance of several drugs in the current clinical used. CYP2C9 has several allelic variant forms each of which arises from single amino acid substitution and could reduce/increase enzyme activities and affect drug metabolism. Mutant alleles may cause serious toxicity in some narrow therapeutic index drugs. CYP2C9*13, one of the CYP2C9 variant forms that is commonly found in Asian population, has a Leu90Pro amino acid substitution that leads to defective drug metabolism in individuals who carry this allele. It has been reported that metabolic activity of CYP2C9*13 was reduced towards some CYP2C9 substrates compared to wildtype. In this study, X-ray crystal structure of human cytochrome P450 2C9 complexed with flurbiprofen (PDB code: 1R9O) was represented to wildtype and the structure of CYP2C9*13 was constructed based on the X-ray crystal structure of CYP2C9-flurbiprofen complex. Herein, molecular docking of CYP2C9*1 and CYP2C9*13 with flurbiprofen was performed in search for flurbiprofen orientation that corresponds to its binding state before undergoing monooxygenation. Subsequently, molecular dynamics simulation was operated to compare binding of flurbiprofen in catalytic cavity of these 2 variants. Substrate access channel of CYP2C9*13 has a dramatic effect on an interaction between the drug and the enzyme. Consequently, this study can lead to an understanding of structural pathology caused by single amino acid change in CYP2C9*13 variant. © 2010 Springer-Verlag Berlin Heidelberg.
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    Water quality control in a closed re-circulating system of Pacific white shrimp (Penaeus vannamei) postlarvae co-cultured with immobilized Spirulina mat
    (2014-01-01) Siriphorn Sombatjinda; Chalermraj Wantawin; Somkiet Techkarnjanaruk; Boonsirm Withyachumnarnkul; Marasri Ruengjitchatchawalya; King Mongkuts University of Technology Thonburi; National Center for Genetics Engineering and Biotechnology; Mahidol University
    Immobilized Spirulina mat was co-cultured with Pacific white shrimp (Penaeus vannamei) postlarvae for water quality control in a closed re-circulating system. During the culture period, the experimental Spirulina mat system showed total ammonia nitrogen and nitrate accumulation rates lower by 32.92 and 32.26 %, respectively, compared with the system without the mat. The water exchange rate in the system with the mat was comparatively reduced by 40 %. Moreover, survival rate, growth rate, and size (length) of the co-cultured shrimp larvae were greater than those of the control (P < 0.05): 72.3 ± 5.2 versus 61.3 ± 4.4 %; 0.55 versus 0.44 mm day-1; and 9.8 ± 0.5 versus 8.7 ± 0.3 mm, respectively. The most frequently observed microbes by PCR-DGGE, either with or without Spirulina mats, were species related to classes γ-, α-, and β- of Proteobacteria (95-98 % similarity), i.e., Nitrosomonas marina, Pseudomonas sp. ITRI66, Fusobacterium ulcerans, and Exiguobacterium arabatum, and species related to Bacteriodetes, i.e., uncultured Flavobacteriales (with a similarity of 96 %). However, species related to Nitrobacter winogradskyi and Stenotrophomonas maltophilia were present only when the mats were applied, suggesting a mutualistic role in the aquaculture system. These bacterial communities, in cooperation with Spirulina sp., could enhance the shrimp response against disease, as well as growth and survival rates, and also improve the shrimp culturing water quality. © 2013 Springer Science+Business Media Dordrecht.