cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.14457/cu.the.2018.84
title: Effect of feedback-resistant aroG overexpression on L-phenylalanine production in Escherichia coli

description: L-Phenylalanine (L-Phe) is one of the most important amino acids in food and pharmaceutical industries. It is widely used as a nutritional supplement and a precursor for the synthesis of food additives. The market of L-Phe has been stimulated by increasing demand for the low-calorie sweetener, aspartame. In Escherichia coli, the key enzyme which catalyzes the first committed step of aromatic amino acid biosynthesis pathway is 3-deoxy-D-arabino-heptulosonate-7- phosphate synthase (DAHP-synthase). The enzyme has 3 isoforms, AroG, AroF and AroH, which are feedback inhibited by L-Phe, L-Tyr and L-Trp, respectively. AroG, encoded by aroG, is the major isoform contributed about 80% of the total DAHP activity. To investigate the feedback inhibition site of AroG, Leu175 was replaced by Asp (L175D) and Gln151 was replaced by Ala (Q151A), Leu (Q151L) and Asn (Q151N). In this study, each feedback resistant aroG was cloned with other pivotal genes in L-Phe biosynthesis pathway (aroB, aroL, phedh and tktA) into pRSFDuet-1 vector. The recombinant plasmid (pBLPTG*) were then co-expressed with pBAD33 vector containing a glycerol uptake gene (glpF) and an aromatic amino acid exporter gene (yddG) (pYF) into E. coli BL21(DE3). The highest production of L-Phe at 1.8 g/L was obtained when both pBLPTG*Q151L & pYF and pBLPTG*Q151N & pYF clones were cultured in glycerol medium for 6 days. These L-Phe yields were 7.7 fold higher than obtained from the control with aroG wild-type (pBLPTG & pYF), while L-Phe yield from pBLPTG*L175D & pYF and pBLPTG*Q151A & pYF were 2.7 and 2.5 fold, respectively. The results revealed that substitution of Leu and Asn at Gln151 could well reduce the feedback inhibition. After that the recombinant clone of pBLPTG*Q151L & pYF was selected for optimization of medium components using response surface methodology (RSM). The maximum L-Phe production at 2.03 g/L was obtained when the pBLPTG*Q151L & pYF was cultured in minimum medium containing 60 g/L glycerol and 42.4 g/L (NH4)2SO4. after induction with 0.02% arabinose at 37 °C for 6 days.
DOI: 10.14457/cu.the.2018.85
title: Surface-enhanced Raman scattering technique for polycyclic aromatic hydrocarbons detection using thiol-functionalized silver nanoparticle films

description: The detection of polycyclic aromatic hydrocarbons (PAHs) is developed based on surface-enhanced Raman scattering (SERS) using silver nanoparticle films as SERS substrates. The films are fabricated by a Langmuir Blodgett (LB) method and the surface of AgNP films are functionalized with various types of aromatic and aliphatic thiols, i.e., naphthalenethiol, phenylethanethiol, pentanethiol, octanethiol, and dodecanethiol, to create a hydrophobic layer for PAHs to attach on and stay in hot spot. The results indicate that nine kinds of PAHs with different structures, i.e., anthracene, chrysene, naphthacene, naphthalene, phenanthrene, pentacene, perylene, pyrene, and triphenylene, can attach on the surfaces of thiol-modified AgNP films as SERS spectra show characteristic patterns for each PAH. Chemometrics methods, i.e., principle component analysis (PCA), cluster separation, partial least square (PLS) regression, and leave-one-out cross validation (LOOCV), are employed for qualitative and quantitative analysis. They show an effective analysis of pure PAH (at the concentration ranging from 10-4–10-7 M) results with the R2 more than 0.9800 and Q2 (R2 of cross-validation model) more than 0.9300. The mixture of two PAHs can be determined with the R2 more than 0.9700 and Q2 more than 0.8900. Moreover, the total concentration of PAHs in the mixture of nine different PAHs can be analyzed with the R2 = 0.9700 and Q2 = 0.9196. This technique can be used to detect PAHs in real sample such as detect PAH in water matrix. SERS technique provides an advantage of sample analysis which does not require any complicated sample pretreatment, convenient and rapid in situ analysis with high sensitivity results.
DOI: 10.14457/cu.the.2018.86
title: Determination of sugar in non-alcoholic beverages using near infrared spectroscopy combined with chemometrics

description: The measurement of Near infrared (NIR) spectroscopy, combined with chemometric techniques, has been widely employed for quality control in food products. This study presents a methodology to optimize the calibration models, called “universal model” of NIR spectra of primary condition (glucose solutions) and maintain the accurate prediction of secondary conditions. For instance, the models were designed for determination of glucose concentration in non-alcoholic drinks. Three stages of methodology including pre-processing, feature selection and main component extraction were applied to spectral data in order to obtain the universal calibration model. The simulated NIR spectra with different noise levels were used to ensure that the model from our methods is able to estimate amount of sugar in any conditions with high accuracy. From the analysis, the universal model improves the prediction for the test set (unseen data) for at least 30 percent compared to the other predictions. Then, it was used to quantify amount of glucose in non-alcoholic beverages (tea, cocoa and coffee in the case). The promising value for root mean square error of prediction (RMSEP) were obtained to be 0.72 (r2 = 0.9972), 0.99 (r2 = 0.9965) and 0.54 (r2 = 0.9940) corresponding to tea, cocoa and coffee system, respectively. Therefore, it might be implied that our universal model approach can be used to estimate glucose concentrations in other non-alcoholic drinks without any requirement of a new calibration model.
DOI: 10.14457/cu.the.2018.87
title: Hybrid materials from covalent organic frameworks and ionic liquids

description: Covalent organic frameworks (COFs) are new type material, whereby their wide range of properties derived from the chemistry of frameworks and their regular porosity. Here in, we reported the successful syntheses of the novel hybrid materials between porous COF material and ionic liquids (ILs). The crystalline porous powder of boroxine‑based COF, so called COF‑5, is reproducible via a condensation reaction between hexahydroxyltriphenylene and phenyldiboronic acid under a mild condition using a conventional heating method. The as‑synthesized COF-5 was characterized with PXRD, FT-IR, TGA and BET techniques, showing that the material contained 1D regular channels caused by π-π stacking of the gauze sheets with a surface area of 1700 m2 g‑1. Ionic liquid, namely 1-vinyl-3-ethylimidazolium bromide (VEIM[Br]) and 1-vinyl-3-ethylimidazolium bis(trifluoromethanesulfonyl)imide (VEIM[NTf2]), were infiltrated into the pores of COF-5 comparing with a silica porous material SBA‑15 and imine‑based COF, named imine‑1, using a vacuum infiltration method. The BET analysis of VEIM[Br]@COF‑5 shows a decrease in surface area of 170 m2 g‑1 along with the PXRD and TGA profile shows that 20 % of infiltrated IL are occupied in pore cavities without a disruption on the host structure. The in‑situ polymerization of VEIM[Br] in porous material was carried out using thermal radical initiator in solvent‑free condition under an inert atmosphere of nitrogen yielding a polyVEIM[Br]@COF-5. The BET surface area of 518 m2 g‑1 implies the higher ordered‑alignment of polymer of VEIM[Br] along the 1D-channel of COF‑5. Moreover, the new hybrid material, VEIM[Br]@COF‑5 was attempted to use as a heterogeneous catalyst in a cycloaddition of CO2 with propylene oxide. The result shows a turnover number (TON) of 64 within 20 hours and turnover frequency (TOF) of 3.2, which calculated from the measured conversions by 1H‑NMR technique. Even through, the hybrid material is not yet be a high effective catalyst, but it has shed some light on the further development of new hybrid materials.
DOI: 10.14457/cu.the.2018.88
title: Extraction of spent green tea leaves as bioactive-compound source

description: Spent green tea leaves (SGTL) are a major contributor to the high cost of commercial tea products because of the large amount of leftover and the cost of disposal. This research investigates on the solvent and time for the extraction of SGTL that provides good yield of potential compound and to separate bioactive compounds as enrich-fractions and pure compounds. The obtained fractions were evaluated for antioxidant, antityrosinase, anticholinesterase and plant growth regulator activities. Caffeine was found in all samples. Among five extracts, the dichloromethane extract revealed high caffeine content (92.8 %peak area), while the methanol extract showed the highest five-catechin content (64.5 %peak area). Further separation of the latter by liquid-liquid extraction, the aqueous phase was extracted with ethyl acetate to gain high catechin family content (EGC, C, EC, EGCG, ECG) fraction with low caffeine. Four subfractions were separated from enrich-catechin family fraction. The enrich-caffeine and enrich-catechin family fractions displayed remarkable biological effects. Caffeine, gallic acid and ECG were bioactive compounds responsible for the biological activity in SGTL. Bioactive compound were isolated from SGTL showed bilogical activity including antioxidant, antityrosinase, anticholinesterase and plant growth regulation. SGTL was proved to be an excellent source of bioactive compounds. The enrich fractions served as prospective materials for the exploration of new multi-functional food and drug formulations.
DOI: 10.14457/cu.the.2018.89
title: Validation of LAMP-LFD Ehrlichia canis DNA sensor Kit

description: Diagnosis of Canine Monocytic Ehrlichiosis is in light of anamesis, visualized cytoplasmic morulae, clinical signs and laboratory test result of platelet counts. The PCR technique is always a definitive confirmatory test of Ehrlichia canis infection. However, the drawback of PCRs test is crucially needed of laboratory equipments. This drawback is somehow enabled newly DNA based technology to be developed in order to eliminate laborious thermocycler and gel electrophoresis. The LAMP-LFD is on focus by using a single temperature to amplify DNA and no gel electrophoresis involved to detect DNA product. LAMP-LFD is included in DNAsensor test kit that recently developed to replace the special equipment requirement for PCRs. This work is aimed to validate LAMP-LFD against nested PCR and single PCR. The validation results showed that nPCR, LAMP-LFD and sPCR are equally in specificity test meanwhile, they have different degrees of sensitivity. nPCR is determined to be the most sensitive method. However, sensitivity of LAMP-LFD and sPCR when compare to nPCR are 78.57% (95% CI= 63.19%-89.70%) and 40.48% (95% CI 25.63% to 56.72%) respectively. The Cohen’s kappa coefficient revealed that nPCR and LAMP-LFD is in substantial agreement (0.785, 89.28% observed agreement) but not sPCR. The application of LAMP-LFD is hence capable of being an alternative method of molecular diagnostic test for CME and a point-of-veterinary care device.
DOI: 10.14457/cu.the.2018.90
title: Innovation of gonadotropin releasing hormone (GnRH)-modified nanocarrier delivered to induce testicular and mammary cell apoptosis

description: The main overall goal of this study is to investigate the application of modified chitosan as a potential vector for apoptotic gene delivery to gonadotropin-releasing hormone receptor (GnRHR)-expressing cells (i.e. testicular cells and mammary cancer cells). This study reported Gonadotropin Releasing Hormone-modified Chitosan (GnRH-CS) nanoparticle as a promising vector for targeted gene delivery, and a GnRH peptide was used for active targeting of a transgene in GnRHR expressing cells. The physiological characterizations of the prepared nanoparticle were investigated by proton nuclear magnetic resonance spectroscopy (1H NMR), Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and Nanosizer. The prepared GnRH-CS was able to condense DNA to form positively charged nanoparticles. In both two-dimensional (2D) and three-dimensional (3D) cell cultures systems, this alternative gene transfer strategy could specifically deliver the reporter genes to a transiently transfected Human Embryonic Kidney cell line model system expressing GnRHR, mouse-derived spermatogonia cells (GC-1 cell line) and mammary cancer cells (MDA-MB-436). Importantly, GnRH-CS exhibited higher transfection activity and lower cell toxicity compared to unmodified CS at the same ratio. From in vitro to in vivo study, Tumor Necrosis Factor alpha (TNF-α) was exploited as a therapeutic gene delivered by GnRH-CS in order to induce testicular cell death in male rat via intra-testicular injection. Significant differences in a reduction in testicular volume on day 7 (P&lt;0.001) were found in all treated groups, compared to the pre-treatment volume. The testicular volume continued to reduce on day 14 (P&lt;0.05) and 28 (P&lt;0.05) in GnRH-CS/TNF-alpha and GnRH-CS groups, respectively. On day 35, after castration, testicular weight and volume of dissected testis were significantly lower in GnRH-CS/TNF-alpha and GnRH-CS groups (P&lt;0.001). Serum testosterone levels did not differ (P&gt;0.05) throughout the observation period. Ultrasonographically and histopathologically, GnRH-CS/TNF-alpha and GnRH-CS induced testicular degeneration and death while TNF-alpha and control groups showed normal findings. GnRH-CS/TNF-alpha treated animals showed higher severity degree of testicular degeneration compared to GnRH-CS treated animals. Moreover in pilot study using mammary gland tumor-bearing nude mice showed promising results in tumor suppression when TNF-α was delivered by the GnRH-CS. It was possible that our study might be apply for non-surgical sterilization and mammary cancer treatment in the future.
DOI: 10.14457/cu.the.2018.91
title: The development of ELISA kit to detect antibody response against porcine epidemic diarrhea virus from colostrum and milk

description: Porcine epidemic diarrhea is caused by porcine epidemic diarrhea virus (PEDV), which causes swine watery diarrhea and higher mortality rates in piglets less than one week of age. Outbreaks of PED affect to economic loss, especially in a swine industrial country. Many strategies were used for preventing the outbreak and infection of PEDV, especially maternal antibody stimulation in pigs and then transfer to piglet through colostrum or milk. Thus, the investigation of antibody level for the situation on the farm is required. The method which convenient and rapid than viral neutralization (VN) test is an enzyme-linked immunosorbent assay (ELISA). The purpose of this study was to develop ELISA test kits to detect antibodies to PEDV from colostrum and milk of pig by preparing antigens of recombinant protein from the spike gene of PEDV and then a validation test of the ELISA test kit was performed from 250 VN positive and 250 VN negative samples. The results of the study showed that ability to produce the protein called S12. The protein is specific to neutralizing antibodies of PEDV and produced from a conserve region of the PEDV gene. S12 protein is 42 kDa of protein size, can be purified either by purification of glutathione S-transferase (GST) gene fusion proteins or histidine-tag protein. Protein S12 can be used as antigen to coat ELISA plate at 10 µg/ml and 20 µg/ml for immunoglobulin (Ig) G and IgA investigation, respectively. In addition, suitable formulations for the test kit were prepared. The precision was verified by the repeatability test, coefficient of variation is less than 10% and has high reproducibility of inter-laboratory results. The correlation between the standardized and ELISA showed strong correlation coefficients from both IgG and IgA. Thus, it can be said that the result is consistent with protection. The cutoff point of optimal density is 0.5, DSN, DSP and accuracy of IgG and IgA were 96.0, 95.6, 95.8 and 94.8, 95.6, 95.2, respectively. As for the cutoff level of the sample to positive ratio (S/P ratio) is 0.4, DSN, DSP and accuracy of IgG and IgA were 95.2, 90.8, 93.0 and 91.6, 93.2, 92.0, respectively. Long term storage of the ELISA kit up to 6 months. In addition, the test kit was used to detect antibodies from feedback and the results show that the ELISA test kit can be used. According to all this study, it can conclude that this ELISA kit can be an alternative possibility for detecting antibody response against PEDV in colostrum and milk.​
DOI: 10.14457/cu.the.2018.92
title: Phenotypic and genotypic characteristics of Extended-Spectrum β-Lactamase (ESBL) Production and Colistin-resistance in Salmonella enterica and Escherichia coli Isolated from​ Pigs and their Meat Products in the Border Provinces between Thailand and Cambodia, Lao PDR and Myanmar

description: A total of 809 samples of pig rectal swab from slaughterhouses (n=441) and pork from retail market (n=368) were collected in the border provinces among Thailand, Cambodia, Lao PDR and Myanmar between October 2016 and March 2017. The objective of this study was to determine resistance to extended-spectrum ß-lactams (ESBLs) and colistin in Salmonella enterica and Escherichia coli. A total of Salmonella (n=463) and E. coli (n=767) were collected and determined for the ESBL-production and for the Minimum Inhibitory Concentrations (MICs) of colistin and; the presence of ESBL gene and mcr gene. The results showed that the prevalence of Salmonella was highest in Cambodia (65.8%) and lowest in Myanmar (13.6%). Serovar Rissen was mostly observed. The prevalence of E. coli in pork was above 87% in all countries. ESBL-producing Salmonella (1.9%) and E. coli (6.3%) were detected at low level. Five bacterial isolates (1 Salmonella and 4 E. coli) were simultaneously resistant to colistin produced by ESBL enzymes. Among the ESBL genes tested, blaCTX-M and blaTEM genes were found in all countries. Twelve Salmonella and 68 E. coli isolates were positive to mcr-1 gene. One Salmonella and 31 E. coli isolates harbored mcr-3 gene. In addition, one Salmonella isolate from pork in Lao PDR carried both mcr-1 and blaCTX-M. One E. coli isolate from pigs in Thailand and one E. coli isolate from pig and pork in Cambodia belonged to mcr-3 and blaCTX-M. These findings demonstrated that pigs and pork serve as reservoirs for the next-generation cephalosporins and colistin-resistant Salmonella and E. coli. Monitoring of resistance to these antibiotics in food animals is needed.
DOI: 10.14457/cu.the.2018.94
title: New Chinese migrants enterpruner in Thailand: the case study of Jong-Thai Jianming Eiw Ea (Group) Co., Ltd.

description: The study of the overseas Chinese in Thailand has been broadly conducted by many scholars. However, such have mainly focused on the overseas Chinese who came from the southeastern part of China, as they were the major part of the Chinese migrants to the Southeast Asian region from the ancient to modern times, and today they still play a great role in this region. Major themes in these studies include the identification of the Chinese migrants (who they were or where they had come from), various Chinese associations, big families of Chinese entrepreneurs and etc. On the contrary, the study of the new Chinese migrants as entrepreneurs from other parts of China, i.e. other than the southeast, has still been limited. This group of Chinese entrepreneurs has no links with the earlier Chinese migrants, so how could they successfully conduct their business in Thailand and what are their connections with the earlier associations? Their presence in Thailand (and indeed in Southeast Asia as a whole) has become a new area for us to study. This thesis focuses on one successful case – that of Jong-Thai Jianming Eiw Ea (Group) Co., Ltd., whose founders are not from the southeastern part of China. The purpose is to examine their business mode, their connection, if any, with the early Chinese associations, and the underlying reasons from their decision to come to operate in Thailand.
DOI: 10.14457/cu.the.2018.95
title: Involvement of nucleus raphe magnus in neuronal excitability of long term paracetamol-treated rats

description: This study examined an involvement of nucleus raphe magnus (NRM) on neuronal excitability at cortex and trigeminal nucleus caudalis (TNC) of chronic paracetamol-treated rats. Male Wistar rats were separated into two main groups. The rats in paracetamol-treated group were intraperitoneally injected with 200 mg/kg paracetamol while 0.9% NaCl was injected in control rats for 30 days. In the first experiment, cortical spreading depression (CSD) event was initiated and direct current (DC) shift was recorded for 2 hours. Thirty minutes after CSD induction, the rats were injected with glutamate, muscimol or saline at NRM and continued signal recording. In the second experiment, TNC neuronal excitability was recorded during intravenous nitroglycerin (NTG) infusion for 2 hours. One hour after NTG infusion, glutamate, muscimol or saline was injected at NRM. After completion of electrophysiological recording, brain and TNC were collected and prepared for Fos immunohistochemical staining. From the first experiment, chronic paracetamol treatment can increase the number of CSD waves and Fos expression in cortex and TNC compared with the control group. Muscimol microinjection at NRM in control group significantly increased the number of CSD waves and Fos expression compared with saline microinjection. Though, glutamate microinjection did not change the number of CSD waves and FOS expression. Moreover, muscimol or glutamate microinjection in paracetamol-treated group did not alter the number of CSD waves and FOS expression compared with saline microinjection. In the second experiment, TNC neuronal excitability and Fos expression were increased after chronic paracetamol treatment compared with control group. Furthermore, glutamate injection in control group can decrease TNC neuronal excitability, while muscimol injection increased TNC neural excitability compared with saline microinjection. However, the neuronal excitability in paracetamol-treated group did not differ after glutamate or muscimol microinjection compared with saline microinjection. From these results, NRM was shown to modulate the cortical and TNC neuronal excitability. Chronic analgesic treatment leads to an alteration of NRM function which affects the central modulating system. The derangement of NRM may contribute to the pathogenesis of medication overuse headache.