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Search Results: 1 - 10 of 3262 matches for " Khim Phin Chong "
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Aging Effect to Accumulation of Lettucenin A in Lettuce after Elicitation with Various Abiotic Elicitors
Wen Dee Ong,Khim Phin Chong
Modern Applied Science , 2009, DOI: 10.5539/mas.v3n2p66
Abstract: A series of experiments were conducted to study the effect of age to accumulation of lettucenin A in lettuce (Lactuca sativa) after various elicitations. Lettuces were challenged with four different types of elicitation method; spray with silver nitrate (AgNO3) or copper sulfate (CuSO4), ultraviolet irradiation and freeze-thawed. Lettucenin A, a type of phytoalexin in lettuce accumulated with a higher concentration after challenged with chemical elicitors, silver nitrate (AgNO3) and copper sulfate (CuSO4). Physical elicitation with irradiation of short wavelength (254nm) ultraviolet radiation and freeze-thawed were also effective in eliciting the production of lettucenin A. However, the amounts were considerably lower compared to those elicited by chemical elicitors. Ultraviolet radiation and freeze-thawed stimulated lettuce to produce lettucenin A at a concentration of 1.52 μg/ml and 0.49 μg/ml respectively while AgNO3 and CuSO4 contributing to accumulation of 4.27 μg/ml and 4.26 μg/ml respectively. The elicitations of lettucenin A were both dependent on types of elicitor and the age of the plant. Treatments with AgNO3 and ultraviolet radiation both showed the same pattern production of lettucenin A. Lettucenin A accumulation increased significantly from week nine to the maximum at week twelve before it decreased to minimum at week eighteen. There is a week relation (R2= 0.69) between the accumulation of lettucenin A with the age of the lettuce with elicitation of silver nitrate. However, there is no relation with induction with ultraviolet radiation. Our results suggest lettuce produces the highest amount of lettucenin A after elicitation with chemical elicitors at twelve weeks old throughout the series of trial.
In Vitro Antimicrobial Activity and Fungitoxicity of Syringic Acid, Caffeic Acid and 4-hydroxybenzoic Acid against Ganoderma Boninense
Khim Phin Chong,Stephen Rossall,Markus Atong
Journal of Agricultural Science , 2009, DOI: 10.5539/jas.v1n2p15
Abstract: This paper discusses the in vitro antimicrobial activity and fungitoxicity of syringic acid, caffeic acid and 4-hydroxybenzoic acid which is found in oil palm root. Experiments were observed for fourteen days, repeated at least three times and data were recorded daily. The antimicrobial activities and fungitoxicity of the phenolics against Ganoderma boninense were expressed in inhibition of radial growth of G. boninense on PDA ameliorated with the three different phenolics with a range concentration of 0.5-2.5 mg/ml. Syringic acid was found to be very fungitoxic to G. boninense even at concentration of 0.5 mg/ml, the lowest concentration tested in this experiment. When the concentration is increase to 1.0mg/ml of syringic acid, the pathogen is inhibited. Caffeic acid and 4-hydroxybenzoic acid were having inhibitory effect with the highest concentration tested; 2.5mg/ml strongly inhibited the growth of G. boninense in comparison to the control.
Experimental Investigation on the Effects of Audible Sound to the Growth of Aspergillus Spp
Poopathy Muthu Karippen,Jedol Dayou,Chong Khim Phin
Modern Applied Science , 2009, DOI: 10.5539/mas.v3n4p137
Abstract: This paper discusses the effect of sound on the growth of fungus, Aspergillus spp. Aspergillus was cultured on Potato Dextrose Agar (PDA) and Potato Dextrose Broth (PDB) and exposed to sound waves for five hours per day for three days. This experiment was observed for three days and data were recorded everyday after the exposure. Four parameters were used to measure the growth of fungus which were colony forming units per ml, optical density, length of germ tube and the diameter of the colony. The results showed that sound waves have effects on the growth of Aspergillus. When Aspergillus was exposed to sound waves with frequencies of 5 kHz, 10 kHz and 15 kHz, the growth was affected by the different frequency. The higher the frequency, the higher the growth inhibition found on Aspergillus. All the three frequencies inhibited the growth of Aspergillus compared to the control (No exposure to sound) and the maximum inhibition occurred at the frequency of 15 kHz.
Experimental Investigation on the Effects of Audible Sound to the Growth of Escherichia coli
Joanna Cho Lee Ying,Jedol Dayou,Chong Khim Phin
Modern Applied Science , 2009, DOI: 10.5539/mas.v3n3p124
Abstract: In this paper, we report an experimental result regarding the effects of audible sound on the growth of Escherichia coli (E. coli). Standardized E. coli suspensions of fixed concentration were used for inoculation throughout the experiment in nutrient agar (NA) and nutrient broth (NB). First, the samples were incubated at 37oC for three hours in a water bath-shaker for NB and in a conventional oven for NA. The samples were then transferred to an acoustic chamber JedMark LV-1 with given sound treatment at controlled temperature of 24±2oC for five hours for NB and 16 hours for NA. Three different tonal frequencies were selected for sound treatment in this experiment which is 1 kHz, 5 kHz and 15 kHz. The growth of E. coli was assessed by their cell number through indirect viable cell counts (E. coli on NA) and direct viable cell counts (E. coli on NB), after the incubation with sound in the acoustic chamber. We found that all selected frequencies were able to promote the growth of E. coli. In particular, the tonal sound of 5 kHz gave significant increase in cell number of E. coli for both growth media.
Lettucenin A and Its Role against Xanthomonas Campestris
Hong Chia Yean,Markus Atong,Khim Phin Chong
Journal of Agricultural Science , 2009, DOI: 10.5539/jas.v1n2p87
Abstract: Lettucenin A is the major phytoalexin produced in lettuce after being elicited by biotic or abiotic elicitors. The production of lettucenin A in leaf can be induced by 5% of CuSO4 and 1% of AgNO3. A clear inhibition zone where the fungi Aspergillus niger failed to develop on TLC plates dipped in hexane: ethyl acetate (1:1, v/v) at Rf 0.45 was observed. Lettucenin A was detected at a retention time of approximately 5.3 min after being injected into the HPLC run with isocratic solvent system containing water: acetonitrile ratio 60:40, (v/v). In vitro antibacterial study with Xanthomonas campestris results showed this pathogen has different sensitivity to all tested concentrations of lettucenin A. The bacteria was more sensitive to higher concentration of lettucenin A (333, 533 and 667 g ml-1), compare to lower concentrations such as 67 g ml-1. Thus, the relationship between the bacteria growth rate and lettucenin A concentration was negatively correlated. However, the bacteria growth rate continues to increase after two hours of incubation. Hence, it is suggested that X. campestris may have the ability to detoxify lettucenin A. The success or failure of X. campestris to invade lettuce may very well depend on the balance between accumulation and degradation of lettucenin A at the invading sites of lettuce. In summary, lettucenin A may play an important role in the resistance of lettuce against microbial colonization.
Soil Nitrogen Phosphorus and Tea Leaf Growth in Organic and Conventional Farming of Selected Fields at Sabah Tea Plantation Slope
Khim. Phin Chong,Tek Yung Ho,Mohamadu Boyie Jalloh
Journal of Sustainable Development , 2009, DOI: 10.5539/jsd.v1n3p117
Abstract: A comparative study of organic and conventional farming system at three different slope sections was conducted in Sabah Tea Plantation to determine the effect of management practices and slope section on soil nitrogen, phosphorus and pH as well as tea leaves size. Soils from two selected fields; B29 (conventional field) and NO3 (organic field) in Sabah Tea Plantation were analyzed using selected soil analysis method with UV spectrophotometer. Organic farming system resulted in significantly higher level of soil pH (4.14), leaf length (15.14 cm) and leaf width (7.33 cm) than conventional farming system soil pH (3.38), leaf length (13.19 cm) and leaf width (5.58 cm). However, conventional farming system produced higher levels of ammonium content (166.16 μg ml-1) than organic farming system (22.56 μg ml1). No significant difference in soil Phosphorus and nitrate content were observed between two farming systems. Results also showed no significant effects of slope sections on all parameters studied. This study has provided basic knowledge on soil Nnitrogen, phosphorus as well as tea growth of organic and conventional farming in Sabah Tea Plantation.
Improved Differential Evolution Algorithm for Parameter Estimation to Improve the Production of Biochemical Pathway
Chuii Khim Chong,Mohd Saberi Mohamad,Safaai Deris,Mohd Shahir Shamsir
International Journal of Interactive Multimedia and Artificial Intelligence , 2012,
Abstract: This paper introduces an improved Differential Evolution algorithm (IDE) which aims at improving its performance in estimating the relevant parameters for metabolic pathway data to simulate glycolysis pathway for yeast. Metabolic pathway data are expected to be of significant help in the development of efficient tools in kinetic modeling and parameter estimation platforms. Many computation algorithms face obstacles due to the noisy data and difficulty of the system in estimating myriad of parameters, and require longer computational time to estimate the relevant parameters. The proposed algorithm (IDE) in this paper is a hybrid of a Differential Evolution algorithm (DE) and a Kalman Filter (KF). The outcome of IDE is proven to be superior than Genetic Algorithm (GA) and DE. The results of IDE from experiments show estimated optimal kinetic parameters values, shorter computation time and increased accuracy for simulated results compared with other estimation algorithms
Simulation of Fermentation Pathway Using Bees Algorithm
Yi Ying LEONG,Chuii Khim CHONG,Lian En CHAI,Safaai DERIS
ADCAIJ : Advances in Distributed Computing and Artificial Intelligence Journal , 2013,
Abstract: In this paper, we propose Bees Algorithm (BA) to enhance the performance in estimating the parameters for metabolic pathway data to simulate fermentation pathway for Saccharomyces cerevisiae. However, the parameter estimation of biological processes has always been a challenging task due to the complexity and nonlinear equations. Therefore, we present this algorithm as a new approach for parameter estimation for biological interactions to obtain more accurate parameter values. The result shows that BA outperforms other estimation algorithms as it produces the most accurate kinetic parameters, which contributes to the precision of simulated kinetic model.
Angiotensin-Converting Enzyme Genotype and Peripheral Arterial Disease in Diabetic Patients
Chin-Hsiao Tseng,Farn-Hsuan Tseng,Choon-Khim Chong,Ching-Ping Tseng,Ju-Chien Cheng
Experimental Diabetes Research , 2012, DOI: 10.1155/2012/698695
Abstract: We investigated the effect of traditional risk factors (hypertension, dyslipidemia and smoking) on the association between angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism and peripheral arterial disease (PAD) in 945 (454 men and 491 women) Taiwanese type 2 diabetic patients with a mean age of 63.5 (SD: 11.4) years. Among them, 81 (31 men and 50 women) had PAD (ankle-brachial index <0.9). The adjusted odds ratios (95% confidence intervals) were 2.48 (1.18–5.21), 1.69 (1.00–2.85) and 1.64 (1.12–2.39), respectively, for recessive (DD versus II
Differential Bees Flux Balance Analysis with OptKnock for In Silico Microbial Strains Optimization
Yee Wen Choon, Mohd Saberi Mohamad, Safaai Deris, Rosli Md. Illias, Chuii Khim Chong, Lian En Chai, Sigeru Omatu, Juan Manuel Corchado
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0102744
Abstract: Microbial strains optimization for the overproduction of desired phenotype has been a popular topic in recent years. The strains can be optimized through several techniques in the field of genetic engineering. Gene knockout is a genetic engineering technique that can engineer the metabolism of microbial cells with the objective to obtain desirable phenotypes. However, the complexities of the metabolic networks have made the process to identify the effects of genetic modification on the desirable phenotypes challenging. Furthermore, a vast number of reactions in cellular metabolism often lead to the combinatorial problem in obtaining optimal gene deletion strategy. Basically, the size of a genome-scale metabolic model is usually large. As the size of the problem increases, the computation time increases exponentially. In this paper, we propose Differential Bees Flux Balance Analysis (DBFBA) with OptKnock to identify optimal gene knockout strategies for maximizing the production yield of desired phenotypes while sustaining the growth rate. This proposed method functions by improving the performance of a hybrid of Bees Algorithm and Flux Balance Analysis (BAFBA) by hybridizing Differential Evolution (DE) algorithm into neighborhood searching strategy of BAFBA. In addition, DBFBA is integrated with OptKnock to validate the results for improving the reliability the work. Through several experiments conducted on Escherichia coli, Bacillus subtilis, and Clostridium thermocellum as the model organisms, DBFBA has shown a better performance in terms of computational time, stability, growth rate, and production yield of desired phenotypes compared to the methods used in previous works.
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