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The direct recovery of recombinant hepatitis B core antigen from disruptate derived from continuous-flow bead milling

Ho CW, Tan WS, Kamaruddin S, Ling TC, Tey BT

Biotechnol Appl Biochem, 2008 May;50(Pt 1):49-59.
PMID: 17760564

HBcAg (hepatitis B core antigen) is a nanoplex bioproduct that has a great potential in the development of therapeutic drugs and vaccines. In the present study, a continuous-flow bead milling for the disruption of Escherichia coli was optimized and a direct recovery protocol to isolate the recombinant HBcAg from the unclarified E. coli disruptate was developed. The optimal condition for continuous-flow bead milling for the release of HBcAg from E. coli was achieved at a feed flow rate of 15 litres/h, biomass concentration of 10% [ww/v (wet weight/vol.)] and impeller tip speed of 14 m/s. The sucrose-density-gradient analysis showed that the particulate form of the HBcAg released by this optimal condition is still preserved. In the direct purification of HBcAg from the unclarified disruptate, the AE-EBAC (anion-exchange expanded-bed adsorption chromatography) technique was employed. A 54% adsorption and 50.7% recovery of HBcAg were achieved in this direct recovery process. The purity of HBcAg recovered was 49.8%, which corresponds to a purification factor of 2.0. ELISA showed that the HBcAg recovered is functionally active.

Matched MeSH terms: Chromatography, Ion Exchange
Fulltext Haemoglobin Lepore in a Malay family: a case report

Pasangna J, George E, Nagaratnam M

Malays J Pathol, 2005 Jun;27(1):33-7.
PMID: 16676691

A 2-year-old Malay boy was brought to the University Malaya Medical Centre for thalassaemia screening. Physical examination revealed thalassaemia facies, pallor, mild jaundice, hepatomegaly and splenomegaly. Laboratory investigations on the patient including studies on the parents lead to a presumptive diagnosis of homozygous Haemoglobin Lepore (Hb Lepore). The aim of this paper is to increase awareness of this rare disorder, this being the first case documented in Malaysia in a Malay. The case also demonstrates the need for this disorder to be included in the differential diagnosis of patients presenting clinically like thalassemia intermedia or thalassemia major. Accurate diagnosis would provide information necessary for prenatal diagnosis, proper clinical management and genetic counseling. The clinical, haematological and laboratory features of this disorder are discussed in this paper.

Matched MeSH terms: Chromatography, High Pressure Liquid
Proteomic analysis of antihypertensive proteins in edible mushrooms

Lau CC, Abdullah N, Shuib AS, Aminudin N

J Agric Food Chem, 2012 Dec 19;60(50):12341-8.
PMID: 23190208 DOI: 10.1021/jf3042159

Mushrooms are high in protein content, which makes them potentially a good source of antihypertensive peptides. Among the mushrooms tested, protein extracts from Pleurotus cystidiosus (E1Pc and E5Pc) and Agaricus bisporus (E1Ab and E3Ab) had high levels of antihypertensive activity. The protein extracts were fractionated by reverse-phase high-performance liquid chromatography (RPHPLC) into six fractions. Fraction 3 from E5Pc (E5PcF3) and fraction 6 from E3Ab (E3AbF6) had the highest antihypertensive activities. SDS-PAGE analysis showed E5PcF3 consisted mainly of low molecular weight proteins, whereas E3AbF6 contained a variety of high to low molecular weight proteins. There were 22 protein clusters detected by SELDI-TOF-MS analysis with five common peaks found in E5PcF3 and E3AbF6, which had m/z values in the range of 3940-11413. This study suggests that the antihypertensive activity in the two mushroom species could be due to proteins with molecular masses ranging from 3 to 10 kDa.

Matched MeSH terms: Chromatography, High Pressure Liquid
Fulltext Comparative bioavailability study of a generic sustained release diclofenac sodium tablet

Magosso E, Yuen KH, Choy WP, Ling SSN, Ng BH, Ur-Rahman N, et al.

Med J Malaysia, 2004 Aug;59(3):352-6.
PMID: 15727381

The bioavailability of a generic diclofenac sodium sustained release tablet preparation (Zolterol, SR) was compared with the innovator product, Voltaren, SR. Twelve healthy adult male volunteers participated in the study, which was conducted according to a randomized, two-way crossover design with a wash out period of one week. The bioavailability of diclofenac was compared using the parameters area under the plasma concentration-time curve (AUC(0-infinity)), peak plasma concentration (Cmax) and time to reach peak plasma concentration (Tmax). No statistically significant difference was observed for both logarithmically transformed AUC(0-infinity), Cmax values and Tmax value of the two preparations.

Matched MeSH terms: Chromatography, High Pressure Liquid
A developmental study on the appearance of tocopherols and tocotrienols in developing palm mesocarp (Elaeis guineensis)

Choo YM, Ma AN, Chuah CH, Khor HT, Bong SC

Lipids, 2004 Jun;39(6):561-4.
PMID: 15554155

The concentration of vitamin E isomers, namely, alpha-tocopherol (alpha-T), alpha-tocotrienol, gamma-tocotrienol, and delta-tocotrienol in palm mesocarp at 4, 8, 12, 16, and 20 wk after anthesis (WAA) were quantified using HPLC coupled with fluorescence detection. alpha-T was detected throughout the palm fruits' maturation process, whereas unsaturated tocotrienols were found only in ripe palm fruits. These developmental results indicate that tocotrienols are synthesized between 16 and 20 WAA.

Matched MeSH terms: Chromatography, High Pressure Liquid
HbA2 levels in normal, beta-thalassaemia and haemoglobin E carriers by capillary electrophoresis

Hafiza A, Malisa MY, Khirotdin RD, Azlin I, Azma Z, Thong MC, et al.

Malays J Pathol, 2012 Dec;34(2):161-4.
PMID: 23424780

The capillary electrophoresis (CE) is a new system that utilizes the principle of electrokinetic separation of molecules in eight electrolyte buffer-filled silica capillaries. In this study, we established the normal ranges of haemoglobin A2 (HbA2) and haemoglobin F (HbF) levels for normal individuals using this system and also the HbA2 level in beta thalassaemia and haemoglobin E (HbE) individuals.

Matched MeSH terms: Chromatography, High Pressure Liquid
Concentrations and profiles of urinary polycyclic aromatic hydrocarbon metabolites (OH-PAHs) in several Asian countries

Guo Y, Senthilkumar K, Alomirah H, Moon HB, Minh TB, Mohd MA, et al.

Environ Sci Technol, 2013 Mar 19;47(6):2932-8.
PMID: 23409981 DOI: 10.1021/es3052262

Concentrations of 12 hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) were determined in 306 urine samples collected from seven Asian countries (China, India, Japan, Korea, Kuwait, Malaysia, and Vietnam) by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The total concentrations of OH-PAHs found in the seven Asian countries were in the following increasing order: Malaysia (median: 2260 pg/mL) < Japan (4030 pg/mL) < China (5770 pg/mL) < India (6750 pg/mL) < Vietnam (8560 pg/mL) < Korea (9340 pg/mL) < Kuwait (10170 pg/mL). The measured urinary concentrations of 1-hydroxypyrene (1-PYR) in samples from Malaysia, Korea, and Japan (∼ 100 pg/mL) were similar to those reported for North America and Western Europe. The concentrations of 1-PYR in urine samples from China, India, and Vietnam were 4-10 times higher than those reported for other countries, thus far. Among the 12 OH-PAH compounds analyzed, hydroxynaphthalene (NAP: sum of 1-hydroxynaphthalene and 2-hydroxynaphthalene) was the dominant compound (accounting for 60-90% of total OH-PAHs), followed by hydroxyphenanthrene (PHEN: sum of 2-hydroxyphenanthrene, 3-hydroxyphenanthrene, 4-hydroxyphenanthrene, and 9-hydroxyphenanthrene [3-16%]), 2-hydroxyfluorene (3-20%), and 1-PYR (2-8%). The total daily intakes (DIs) of PAHs were estimated based on the urinary concentrations of their metabolites. The DIs of naphthalene were found to be higher for populations in Korea, Kuwait, and Vietnam (> 10 μg/day) than those of the other countries studied (∼ 5 μg/day). The DIs of phenanthrene and pyrene (> 10 μg/day) in the populations of China, India, and Vietnam were higher than those estimated for the populations in the other countries studied (∼ 5 μg/day).

Matched MeSH terms: Chromatography, High Pressure Liquid
Modeling growth rate and assessing aflatoxins production by Aspergillus flavus as a function of water activity and temperature on polished and brown rice

Mousa W, Ghazali FM, Jinap S, Ghazali HM, Radu S

J Food Sci, 2013 Jan;78(1):M56-63.
PMID: 23301606 DOI: 10.1111/j.1750-3841.2012.02986.x

The aim of this study was to model the radial growth rate and to assess aflatoxin production by Aspergillus flavus as a function of water activity (a(w) 0.82 to 0.92) and temperature (12 to 42 °C) on polished and brown rice. The growth of the fungi, expressed as colony diameter (mm) was measured daily, and the aflatoxins were analyzed using HPLC with a fluorescence detector. The growth rates were estimated using the primary model of Baranyi, which describes the change in colony radius as a function of time. Total of 2 secondary models were used to describe the combined effects of a(w) and temperature on the growth rates. The models were validated using independent experimental data. Linear Arrhenius-Davey model proved to be the best predictor of A. flavus growth rates on polished and brown rice followed by polynomial model. The estimated optimal growth temperature was around 30 °C. A. flavus growth and aflatoxins were not detected at 0.82 a(w) on polished rice while growth and aflatoxins were detected at this a(w) between 25 and 35 °C on brown rice. The highest amounts of toxins were formed at the highest a(w) values (0.90 to 0.92) at a temperature of 20 °C after 21 d of incubation on both types of rice. Nevertheless, the consistencies of toxin production within a wider range of a(w) values occurred between 25 to 30 °C. Brown rice seems to support A. flavus growth and aflatoxin production more than the polished rice.

Matched MeSH terms: Chromatography, High Pressure Liquid
Profiling of metabolites in oil palm mesocarp at different stages of oil biosynthesis

Neoh BK, Teh HF, Ng TL, Tiong SH, Thang YM, Ersad MA, et al.

J Agric Food Chem, 2013 Feb 27;61(8):1920-7.
PMID: 23384169 DOI: 10.1021/jf304561f

Oil palm is one of the most productive oil producing crops and can store up to 90% oil in its fruit mesocarp. However, the biosynthetic regulation and drivers of palm mesocarp development are still not well understood. Multiplatform metabolomics technology was used to profile palm metabolites during six critical stages of fruit development in order to better understand lipid biosynthesis. Significantly higher amino acid levels were observed in palm mesocarp preceding lipid biosynthesis. Nucleosides were found to be in high concentration during lipid biosynthesis, whereas levels of metabolites involved in the tricarboxylic acid cycle were more concentrated during early fruit development. Apart from insights into the regulation of metabolites during fruit development in oil palm, these results provide potentially useful metabolite yield markers and genes of interest for use in breeding programs.

Matched MeSH terms: Chromatography, High Pressure Liquid
Frequencies of A(TA)7TAA, G71R, and G493R mutations of the UGT1A1 gene in the Malaysian population

Yusoff S, Van Rostenberghe H, Yusoff NM, Talib NA, Ramli N, Ismail NZ, et al.

Biol. Neonate, 2006;89(3):171-6.
PMID: 16210851

Gilbert syndrome is caused by defects in the uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) gene. These mutations differ among different populations and many of them have been found to be genetic risk factors for the development of neonatal jaundice.

Matched MeSH terms: Chromatography, High Pressure Liquid
Isolation of palm oil-utilising, polyhydroxyalkanoate (PHA)-producing bacteria by an enrichment technique

Alias Z, Tan IK

Bioresour Technol, 2005 Jul;96(11):1229-34.
PMID: 15734309

In early attempts to isolate palm oil-utilising bacteria from palm oil mill effluent (POME), diluted liquid samples of POME were spread on agar containing POME as primary nutrient. 45 purified colonies were screened for intracellular lipids by staining with Sudan Black B. Of these, 10 isolates were positively stained. The latter were grown in a nitrogen-limiting medium with palm olein (a triglyceride) or saponified palm olein (salts of fatty acids) as carbon source. None of the isolates grew in the palm olein medium but all grew well in the saponified palm olein medium. Of the latter however, only one isolate was positively stained with Nile Blue A, indicating the presence of PHA. This method did not successfully generate bacterial isolates which could metabolise palm olein to produce PHA. An enrichment technique was therefore developed whereby a selective medium was designed. The latter comprised minerals and palm olein (1% w/v) as sole carbon source to which POME (2.5% v/v) was added as the source of bacteria. The culture was incubated with shaking at 30 degrees C for 4 weeks. Out of seven isolates obtained from the selective medium, two isolates, FLP1 and FLP2, could utilise palm olein for growth and production of the homopolyester, poly(3-hydroxybutyrate). FLP1 is gram-negative and is identified (BIOLOG) to have 80% similarity to Burkholderia cepacia. When grown with propionate or valerate, FLP1 produced a copolyester, poly(3-hydroxybutyrate-co-3-hydroxyvalerate).

Matched MeSH terms: Chromatography, Gas
Fulltext The effects of Secondhand Smoke (SHS) exposure on microvascular endothelial function among healthy women

Sanip Z, Hanaffi SH, Ahmad I, Yusoff SS, Rasool AH, Yusoff HM

Tob Induc Dis, 2015;13(1):32.
PMID: 26346914 DOI: 10.1186/s12971-015-0052-9

BACKGROUND: Studies have demonstrated that secondhand smoke (SHS) exposure could impair endothelial function. However, the effect of SHS exposure specifically on microvascular endothelial function is not well understood. This study aimed to determine the effects of SHS exposure on microvascular endothelial function among non-smoking, generally healthy women.
FINDINGS: We studied 127 women; and based on their hair nicotine levels measured using gas chromatography-mass spectrometry, 25 of them were categorized as having higher hair nicotine levels, 25 were grouped as having lower hair nicotine and 77 women were grouped into the non-detected group. The non-detected group did not have detectable levels of hair nicotine. Anthropometry, blood pressure (BP), lipid profile and high-sensitivity C-reactive protein (hsCRP) were measured accordingly. Microvascular endothelial function was assessed non-invasively using laser Doppler fluximetry and the process of iontophoresis involving acetylcholine and sodium nitroprusside as endothelium-dependent and endothelium-independent vasodilators respectively. The mean hair nicotine levels for higher and lower hair nicotine groups were 0.74 (1.04) and 0.05 (0.01) ng/mg respectively. There were no significant differences in anthropometry, BP, lipid profile and hsCRP between these groups. There were also no significant differences in the microvascular perfusion and endothelial function between these groups.
CONCLUSION: In this study, generally healthy non-smoking women who have higher, lower and non-detected hair nicotine levels did not show significant differences in their microvascular endothelial function. Low levels of SHS exposure among generally healthy non-smoking women may not significantly impair their microvascular endothelial function.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Expression and purification of the matrix protein of Nipah virus in baculovirus insect cell system

Masoomi Dezfooli S, Tan WS, Tey BT, Ooi CW, Hussain SA

Biotechnol Prog, 2016 Jan-Feb;32(1):171-7.
PMID: 26519022 DOI: 10.1002/btpr.2192

Nipah virus (NiV) causes fatal respiratory illness and encephalitis in humans and animals. The matrix (M) protein of NiV plays an important role in the viral assembly and budding process. Thus, an access to the NiV M protein is vital to the design of viral antigens as diagnostic reagents. In this study, recombinant DNA technology was successfully adopted in the cloning and expression of NiV M protein. A recombinant expression cassette (baculovirus expression vector) was used to encode an N-terminally His-tagged NiV M protein in insect cells. A time-course study demonstrated that the highest yield of recombinant M protein (400-500 μg) was expressed from 107 infected cells 3 days after infection. A single-step purification method based on metal ion affinity chromatography was established to purify the NiV M protein, which successfully yielded a purity level of 95.67% and a purification factor of 3.39. The Western blotting and enzyme-linked immunosorbent assay (ELISA) showed that the purified recombinant M protein (48 kDa) was antigenic and reacted strongly with the serum of a NiV infected pig.

Matched MeSH terms: Chromatography, Affinity
Fulltext Antihyperglycemic Effect of Methanol Extract of Syzygium polyanthum (Wight.) Leaf in Streptozotocin-Induced Diabetic Rats

Widyawati T, Yusoff NA, Asmawi MZ, Ahmad M

Nutrients, 2015 Sep;7(9):7764-80.
PMID: 26389944 DOI: 10.3390/nu7095365

Syzygium polyanthum (S. polyanthum), a plant belonging to Myrtaceae, is widely used in Indonesian and Malaysian cuisines. Diabetic patients in Indonesia also commonly use it as a traditional medicine. Hence, this study was conducted to investigate the antihyperglycemic effect of the methanol extract (ME) of S. polyanthum leaf and its possible mechanisms of action. To test for hypoglycemic activity, ME was administered orally to normal male Sprague Dawley rats after a 12-h fast. To further test for antihyperglycemic activity, the same treatment was administered to glucose-loaded (intraperitoneal glucose tolerance test, IPGTT) and streptozotocin (STZ)-induced diabetic rats, respectively. Hypoglycemic test in normal rats did not show significant reduction in blood glucose levels (BGLs) by the extract. Furthermore, IPGTT conducted on glucose-loaded normal rats also did not show significant reduction of BGLs. However, repeated administration of metformin and three doses of ME (250, 500 and 1000 mg/kg) for six days caused significant reduction of fasting BGLs in STZ-induced diabetic rats. The possible mechanisms of action of S. polyanthum antihyperglycemic activity were assessed by measurement of intestinal glucose absorption and glucose uptake by isolated rat abdominal muscle. It was found that the extract not only inhibited glucose absorption from the intestine but also significantly increased glucose uptake in muscle tissue. A preliminary phytochemical qualitative analysis of ME indicated the presence of tannins, glycosides, flavonoids, alkaloids and saponins. Additionally, Gas Chromatography-Mass Spectrometry (GC-MS) analysis detected squalene. In conclusion, S. polyanthum methanol leaf extract exerts its antihyperglycemic effect possibly by inhibiting glucose absorption from the intestine and promoting glucose uptake by the muscles.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Baseline distribution and sources of linear alkyl benzenes (LABs) in surface sediments from Brunei Bay, Brunei

Alkhadher SAA, Zakaria MP, Yusoff FM, Kannan N, Suratman S, Keshavarzifard M, et al.

Mar Pollut Bull, 2015 Dec 15;101(1):397-403.
PMID: 26478457 DOI: 10.1016/j.marpolbul.2015.10.011

Sewage pollution is one of major concerns of coastal and shoreline settlements in Southeast Asia, especially Brunei. The distribution and sources of LABs as sewage molecular markers were evaluated in surface sediments collected from Brunei Bay. The samples were extracted, fractionated and analyzed using gas chromatography- mass spectrometry (GC-MS). LABs concentrations ranged from 7.1 to 41.3 ng g(-1) dry weight (dw) in surficial sediments from Brunei Bay. The study results showed LABs concentrations variably due to the LABs intensity and anthropogenic influence along Brunei Bay in recent years. The ratio of Internal to External isomers (I/E ratio) of LABs in sediment samples from Brunei Bay ranged from 0.56 to 2.17 along Brunei Bay stations, indicating that the study areas were receiving primary and secondary effluents. This is the first study carried out to assess the distribution and sources of LABs in surface sediments from Brunei Bay, Brunei.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Blowfly Larval Tissues as a Secondary Detector for Determining Paraquat-Related Death in Rabbit Carcass

Lawai V, Abdul Rahim NA, Ngaini Z

J Forensic Sci, 2015 11;60(6):1620-4.
PMID: 26382214 DOI: 10.1111/1556-4029.12852

Paraquat poisoning is commonly associated with suicide or homicide in Malaysia. In a case involving advanced body decomposition, pathological analysis regarding the cause of death may become difficult or almost impossible. Insects serve as common alternative matrix for poison detection in forensic analysis. Paraquat detection via secondary bioaccumulation in fly larvae tissue has never been reported. In this study, tissues from blowfly larvae collected from a rabbit carcass with paraquat poisoning were analyzed for secondary bioaccumulation. Larvae samples were collected and analyzed using liquid-liquid extraction. The detection was performed via reduction of quaternary ammonium presence in paraquat and analyzed using gas chromatography-mass spectrometry (GC-MS) with selected ion monitoring mode (SIM mode). GC-MS showed the elution of reduced paraquat was at retention time 12.8 min. Blowfly larvae tissue has proven useful as a secondary detector in paraquat-related deaths.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Simultaneous determination of three organophosphorus pesticides in different food commodities by gas chromatography with mass spectrometry

Vijaya Bhaskar Reddy A, Yusop Z, Jaafar J, Bin Aris A, Abdul Majid Z, Umar K, et al.

J Sep Sci, 2016 Jun;39(12):2276-83.
PMID: 27095506 DOI: 10.1002/jssc.201600155

A sensitive and selective gas chromatography with mass spectrometry method was developed for the simultaneous determination of three organophosphorus pesticides, namely, chlorpyrifos, malathion, and diazinon in three different food commodities (milk, apples, and drinking water) employing solid-phase extraction for sample pretreatment. Pesticide extraction from different sample matrices was carried out on Chromabond C18 cartridges using 3.0 mL of methanol and 3.0 mL of a mixture of dichloromethane/acetonitrile (1:1 v/v) as the eluting solvent. Analysis was carried out by gas chromatography coupled with mass spectrometry using selected-ion monitoring mode. Good linear relationships were obtained in the range of 0.1-50 μg/L for chlorpyrifos, and 0.05-50 μg/L for both malathion and diazinon pesticides. Good repeatability and recoveries were obtained in the range of 78.54-86.73% for three pesticides under the optimized experimental conditions. The limit of detection ranged from 0.02 to 0.03 μg/L, and the limit of quantification ranged from 0.05 to 0.1 μg/L for all three pesticides. Finally, the developed method was successfully applied for the determination of three targeted pesticides in milk, apples, and drinking water samples each in triplicate. No pesticide was found in apple and milk samples, but chlorpyrifos was found in one drinking water sample below the quantification level.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Aqueous chlorination of mefenamic acid: kinetics, transformation by-products and ecotoxicity assessment

Adira Wan Khalit WN, Tay KS

Environ Sci Process Impacts, 2016 May 18;18(5):555-61.
PMID: 27062128 DOI: 10.1039/c6em00017g

Mefenamic acid (Mfe) is one of the most frequently detected nonsteroidal anti-inflammatory drugs in the environment. This study investigated the kinetics and the transformation by-products of Mfe during aqueous chlorination. The potential ecotoxicity of the transformation by-products was also evaluated. In the kinetic study, the second-order rate constant (kapp) for the reaction between Mfe and free available chlorine (FAC) was determined at 25 ± 0.1 °C. The result indicated that the degradation of Mfe by FAC is highly pH-dependent. When the pH was increased from 6 to 8, it was found that the kapp for the reaction between Mfe and FAC was decreased from 16.44 to 4.4 M(-1) s(-1). Characterization of the transformation by-products formed during the chlorination of Mfe was carried out using liquid chromatography-quadrupole time-of-flight accurate mass spectrometry. Four major transformation by-products were identified. These transformation by-products were mainly formed through hydroxylation, chlorination and oxidation reactions. Ecotoxicity assessment revealed that transformation by-products, particularly monohydroxylated Mfe which is more toxic than Mfe, can be formed during aqueous chlorination.

Matched MeSH terms: Chromatography, Liquid
N,N-dimethylhexadecyl carboxymethyl chitosan as a potential carrier agent for rotenone

Kamari A, Aljafree NF, Yusoff SN

Int J Biol Macromol, 2016 Jul;88:263-72.
PMID: 27041651 DOI: 10.1016/j.ijbiomac.2016.03.071

In this study, an amphiphilic chitosan derivative namely N,N-dimethylhexadecyl carboxymethyl chitosan (DCMC) was synthesised and applied for the first time as a carrier agent for rotenone. The physical and chemical properties of DCMC were characterised by using Fourier Transform Infrared Spectrometer (FTIR), Proton Nuclear Magnetic Resonance Spectrometer ((1)H NMR), CHN-O Elemental Analyser, Thermogravimetric Analyser (TGA) and Differential Scanning Calorimeter (DSC). DCMC was soluble in acidic (except pH 4), neutral and basic media with percent of transmittance (%T) values ranged from 67.2 to 99.4%. The critical micelle concentration (CMC) was determined as 0.095mg/mL. Transmission Electron Microscopy (TEM) analysis confirmed that DCMC has formed self-aggregates and exhibited spherical shape with the size of 65.5-137.0nm. The encapsulation efficiency (EE) and loading capacity (LC) of DCMC micelles with different weight ratios (DCMC:rotenone; 5:1, 50:1 and 100:1) were determined by using High Performance Liquid Chromatography (HPLC). The weight ratio of 100:1 gave the best EE with the value of more than 95.0%. DCMC micelles performed an excellent ability to control the release of rotenone, of which 99.0% of rotenone was released within 48h. Overall, DCMC has several key features to be an effective carrier agent for pesticide formulations.

Matched MeSH terms: Chromatography, High Pressure Liquid
Fulltext In Vitro Analysis of Metabolites Secreted during Infection of Lung Epithelial Cells by Cryptococcus neoformans

Liew KL, Jee JM, Yap I, Yong PV

PLoS One, 2016;11(4):e0153356.
PMID: 27054608 DOI: 10.1371/journal.pone.0153356

Cryptococcus neoformans is an encapsulated basidiomycetous yeast commonly associated with pigeon droppings and soil. The opportunistic pathogen infects humans through the respiratory system and the metabolic implications of C. neoformans infection have yet to be explored. Studying the metabolic profile associated with the infection could lead to the identification of important metabolites associated with pulmonary infection. Therefore, the aim of the study was to simulate cryptococcal infection at the primary site of infection, the lungs, and to identify the metabolic profile and important metabolites associated with the infection at low and high multiplicity of infections (MOI). The culture supernatant of lung epithelial cells infected with C. neoformans at MOI of 10 and 100 over a period of 18 hours were analysed using gas chromatography mass spectrometry. The metabolic profiles obtained were further analysed using multivariate analysis and the pathway analysis tool, MetaboAnalyst 2.0. Based on the results from the multivariate analyses, ten metabolites were selected as the discriminatory metabolites that were important in both the infection conditions. The pathways affected during early C. neoformans infection of lung epithelial cells were mainly the central carbon metabolism and biosynthesis of amino acids. Infection at a higher MOI led to a perturbance in the β-alanine metabolism and an increase in the secretion of pantothenic acid into the growth media. Pantothenic acid production during yeast infection has not been documented and the β-alanine metabolism as well as the pantothenate and CoA biosynthesis pathways may represent underlying metabolic pathways associated with disease progression. Our study suggested that β-alanine metabolism and the pantothenate and CoA biosynthesis pathways might be the important pathways associated with cryptococcal infection.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry

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