MyMedR

Displaying publications 21 - 40 of 42 in total

Abstract:

Sort:

Fatty acid preference of mycelium-bound lipase from a locally isolated strain of Geotrichum candidum

Loo JL, Lai OM, Long K, Ghazali HM

World J Microbiol Biotechnol, 2007 Dec;23(12):1771-8.
PMID: 27517833 DOI: 10.1007/s11274-007-9427-2

Mycelium-bound lipase (MBL) was prepared using a strain of Geotrichum candidum isolated from local soil. At the time of maximum lipase activity (54 h), the mycelia to which the lipase was bound were harvested by filtration and centrifugation. Dry MBL was prepared by lyophilizing the mycelia obtained. The yield of MBL was 3.66 g/l with a protein content of 44.11 mg/g. The lipase activity and specific lipase activity were 22.59 and 510 U/g protein, respectively. The moisture content of the MBL was 3.85%. The activity of free (extracellular) lipase in the culture supernatant (after removal of mycelia) was less than 0.2 U/ml. The MBL showed selectivity for oleic acid over palmitic acid during hydrolysis of palm olein, indicating that the lipase from G. candidum displayed high substrate selectivity for unsaturated fatty acid containing a cis-9 double bond, even in crude form. This unique specificity of MBL could be a direct, simple and inexpensive way in the fats and oil industry for the selective hydrolysis or transesterification of cis-9 fatty acid residues in natural triacylglycerols.

Matched MeSH terms: Centrifugation
Fulltext Two-Step Purification of Glycerol as a Value Added by Product From the Biodiesel Production Process

Abdul Raman AA, Tan HW, Buthiyappan A

Front Chem, 2019;7:774.
PMID: 31799239 DOI: 10.3389/fchem.2019.00774

For every ton of biodiesel produced, about 100 kg of glycerol is also generated as a by-product. The traditional method of removing glycerol is mainly by gravity separation or centrifugation. This method generates crude glycerol, which may still contain impurities such as methanol, oil, soap, salt, and other organic materials at ppm levels. The effective usage of crude glycerol is important to improve the economic sustainability of the biodiesel industry while reducing the environmental impacts caused by the generated waste. The application and value of crude glycerol can be enhanced if these impurities are removed or minimized. Thus, it is important to develop a method which can increase the economic and applicable value of crude glycerol. Therefore, in the present study, the dual step purification method comprised of acidification and ion exchange techniques has been used to purify the crude glycerol and convert it into higher-value products. The acidification process started with the pH adjustment of the crude glycerol, using phosphoric acid to convert soap into fatty acid and salts. Then, the pretreated glycerol was further purified by ion exchange with a strong cation H+ resin. Gas chromatography (GC) was used to analyze both crude and purified glycerol and expressed as the weight percentage of glycerol content. A maximum glycerol purity of 98.2% was obtained after the dual step purification method at the optimized conditions of 60% of solvent, the flow rate of 15 mL/min and 40 g of resin. Further, the glycerol content measured being within the accepted amount of BS 2621:1979. Therefore, this study has proven that the proposed crude glycerol purification process is effective in improving the glycerol purity and could enhance the applicability of glycerol in producing value-added products which bring new revenue to the biodiesel industry.

Matched MeSH terms: Centrifugation
Isolation and fractionation of cellulose nanocrystals from kenaf core

Hanisah Syed Sulaiman, Chin HC, Chan CH, Sarani Zakaria, Sharifah Nabihah Syed Jaafar

Sains Malaysiana, 2015;44:1635-1642.

In this study, cellulose nanocrystals (CNC) were produced using acid hydrolysis method. Kenaf core was pretreated with 4
wt. % sodium hydroxide (NaOH), followed by bleaching using 1.7 wt. % sodium chlorite (NaClO2
) in acetate buffer. The
bleached fiber was acid hydrolyzed for 45 and 55 min using 64 wt. % sulfuric acid (H2
SO4
). The size distribution of the
CNC segregated via differential centrifugation with different speed was also investigated. The CNC suspension obtained
was centrifuged at 3000, 6000, 9000 and 12000 rpm. The resultant CNC suspension collected was characterized using
Fourier transform infrared (FTIR) analysis, X-ray diffraction (XRD) and transmission electron microscopy (TEM). FTIR
results showed the progressive removal of non-cellulosic constituents for each subsequent treatment. It also showed that
the CNC produced after hydrolysing for 55 min has the highest degree of crystallinity (81.15%). CNC produced from acid
hydrolysis process of 45 min have lengths between 50 and 270 nm while CNC produced from acid hydrolysis process of
55 min have length around 40 to 370 nm.

Matched MeSH terms: Centrifugation
Fulltext Optimization of Washing Processes in Solvothermal Synthesis of Nickel-Based MOF-74

Kamal K, Bustam MA, Ismail M, Grekov D, Mohd Shariff A, Pré P

Materials (Basel), 2020 Jun 17;13(12).
PMID: 32560394 DOI: 10.3390/ma13122741

Solvothermal synthesis is the most preferable preparation technique of metal-organic frameworks (MOFs) that consists of reactants mixing, ultrasonication, solvothermal reaction, product washing, and solvent evacuation. Owing to fast reaction kinetics in solvothermal reaction, this technique allows for production of uniform MOF particles with high crystallinity, high phase purity, and small particle sizes. However, it exhibits some difficulties of washing processes that may involve the blockage of pores due to incomplete removal of reactive medium from MOF products. The present study proposes an improvement of washing processes by introducing centrifugal separations with optimized parameters at two different stages: after reaction and after product washing. Nickel‑based MOF‑74 was synthesized as the experimental material for this purpose. The quality of the produced sample was evaluated by gas adsorption performance using CO2 at 1 bar and 25 °C. The final sample of the optimized synthesis routes was able to adsorb 5.80 mmol/g of CO2 uptake, which was competitive with literature data and significantly higher than the sample of the basic synthesis. Fourier‑transform infrared spectroscopy (FTIR) and powder X‑ray diffraction (PXRD) analysis revealed that the sample displayed much higher crystallinity structure and was clean from impurities after centrifugations. The outcome indicated the success of separation between MOF products and reactive medium during washing processes, leading to the effective pore activation of MOFs.

Matched MeSH terms: Centrifugation
Evaluation of formalin-ether sedimentation and trichrome staining techniques: its effectiveness in detecting Entamoeba histolytica/dispar/moshkovskii in stool samples

Anuar TS, Al-Mekhlafi HM, Abdul Ghani MK, Abu Bakar E, Azreen SN, Salleh FM, et al.

J Microbiol Methods, 2013 Mar;92(3):344-8.
PMID: 23361047 DOI: 10.1016/j.mimet.2013.01.010

This study was conducted to evaluate two routinely microscopic diagnostic methods in comparison with single-round PCR assay as the reference technique to detect Entamoeba histolytica/dispar/moshkovskii. Examination was performed on 500 stool samples obtained from Orang Asli communities in different states of Malaysia using formalin-ether sedimentation, trichrome staining and single-round PCR techniques. Ninety-three stool samples were detected E. histolytica/dispar/moshkovskii positive by routine microscopy, while single-round PCR detected 106 positive samples. Additional positives detected by PCR assay were eventually confirmed to be negative by both microscopic techniques. Detection rate of E. histolytica/dispar/moshkovskii was highest in combination techniques (18.6%), followed by trichrome staining (13.4%) and formalin-ether sedimentation (11.2%) techniques. Single-round PCR detected 21.2% of the stool samples. The sensitivity and specificity of formalin-ether sedimentation and trichrome staining techniques compared to the reference technique were 31.1% (95% CI: 29.0-36.0) and 94.2% (95% CI: 89.8-98.9), and 53.8% (95% CI: 46.0-76.2) and 97.5% (95% CI: 92.8-99.1), respectively. However, the sensitivity [59.4% (95% CI: 48.9-78.5)] of the method increased when both techniques were performed together, but the specificity decreased to 92.4% (95% CI: 81.0-98.0). The agreement between the reference technique, trichrome staining and combination techniques were statistically significant by Kappa statistics (trichrome staining: K = 0.592, p < 0.05; combination techniques: K = 0.543, p < 0.05). Hence, the combination technique is recommended to be used as a screening method in the diagnosis of E. histolytica/dispar/moshkovskii infections either for clinical or epidemiological study.

Matched MeSH terms: Centrifugation/methods
Isolation of viable Toxoplasma gondii cysts from brain samples for oral infection

Puvanesuaran VR, Ibrahim N, Noordin R, Balakrishnan V

Eur Rev Med Pharmacol Sci, 2012 Sep;16(9):1179-83.
PMID: 23047500

AIM: A method was developed to separate contaminant-free viable Toxoplasma gondii cysts from brain samples of infected mice for molecular biology studies and reinfection.
MATERIALS AND METHODS: The mice brains were homogenized and washed with phosphate buffered saline (PBS) Tween 80 prior to fractionation using 19-22% dextran solution. Finally, the supernatant was purified by two-step membrane filtration (100-160 microm and < 10 microm) to obtain pure T. gondii cyst. The isolates were analyzed through microscopic observation, qPCR and by reinfection of new batch of mice.
RESULTS: T. gondii cysts were best isolated with 21% dextran solution and two step filtration.
CONCLUSIONS: The method was observed not to disrupt the integrity of the cysts containing bradyzoites. In addition, the isolated cysts in the filtrate were found to be contaminant-free, viable and able to infect healthy mice when introduced orally; which, mimics the natural infectivity pathway.

Matched MeSH terms: Centrifugation, Density Gradient
Aerobic granular sludge formation for high strength agro-based wastewater treatment

Abdullah N, Ujang Z, Yahya A

Bioresour Technol, 2011 Jun;102(12):6778-81.
PMID: 21524907 DOI: 10.1016/j.biortech.2011.04.009

The present study investigates the formation of aerobic granular sludge in sequencing batch reactor (SBR) fed with palm oil mill effluent (POME). Stable granules were observed in the reactor with diameters between 2.0 and 4.0mm at a chemical oxygen demand (COD) loading rate of 2.5 kg COD m(-3) d(-1). The biomass concentration was 7600 mg L(-1) while the sludge volume index (SVI) was 31.3 mL g SS(-1) indicating good biomass accumulation in the reactor and good settling properties of granular sludge, respectively. COD and ammonia removals were achieved at a maximum of 91.1% and 97.6%, respectively while color removal averaged at only 38%. This study provides insights on the development and the capabilities of aerobic granular sludge in POME treatment.

Matched MeSH terms: Centrifugation
Reversible thermo-pneumatic valves on centrifugal microfluidic platforms

Aeinehvand MM, Ibrahim F, Harun SW, Kazemzadeh A, Rothan HA, Yusof R, et al.

Lab Chip, 2015 Aug 21;15(16):3358-69.
PMID: 26158597 DOI: 10.1039/c5lc00634a

Centrifugal microfluidic systems utilize a conventional spindle motor to automate parallel biochemical assays on a single microfluidic disk. The integration of complex, sequential microfluidic procedures on these platforms relies on robust valving techniques that allow for the precise control and manipulation of fluid flow. The ability of valves to consistently return to their former conditions after each actuation plays a significant role in the real-time manipulation of fluidic operations. In this paper, we introduce an active valving technique that operates based on the deflection of a latex film with the potential for real-time flow manipulation in a wide range of operational spinning speeds. The reversible thermo-pneumatic valve (RTPV) seals or reopens an inlet when a trapped air volume is heated or cooled, respectively. The RTPV is a gas-impermeable valve composed of an air chamber enclosed by a latex membrane and a specially designed liquid transition chamber that enables the efficient usage of the applied thermal energy. Inputting thermo-pneumatic (TP) energy into the air chamber deflects the membrane into the liquid transition chamber against an inlet, sealing it and thus preventing fluid flow. From this point, a centrifugal pressure higher than the induced TP pressure in the air chamber reopens the fluid pathway. The behaviour of this newly introduced reversible valving system on a microfluidic disk is studied experimentally and theoretically over a range of rotational frequencies from 700 RPM to 2500 RPM. Furthermore, adding a physical component (e.g., a hemispherical rubber element) to induce initial flow resistance shifts the operational range of rotational frequencies of the RTPV to more than 6000 RPM. An analytical solution for the cooling of a heated RTPV on a spinning disk is also presented, which highlights the need for the future development of time-programmable RTPVs. Moreover, the reversibility and gas impermeability of the RTPV in the microfluidic networks are validated on a microfluidic disk designed for performing liquid circulation. Finally, an array of RTPVs is integrated into a microfluidic cartridge to enable sequential aliquoting for the conversion of dengue virus RNA to cDNA and the preparation of PCR reaction mixtures.

Matched MeSH terms: Centrifugation
Fulltext Therapeutic plasma exchange (TPE) for semi-critical neurology presentations in a non-acute neurology set-up: clinical practice and challenges

Fu KS, Wong PY, Hiew FL

BMJ Neurol Open, 2020;2(1):e000020.
PMID: 33681775 DOI: 10.1136/bmjno-2019-000020

Introduction: Therapeutic plasma exchange (TPE) for semi-critical neurological manifestations can be managed in non-acute setting instead of critical care unit. In 2014, we established a non-acute neurology TPE unit for semi-critical haemodynamically stable patients. In this study, we aimed to evaluate the technical and safety parameters from the first 3 years of service.
Materials and methods: We analysed prospectively collected TPE data for patients treated with centrifugation TPE at our non-acute neurology TPE unit in Kuala Lumpur Hospital between May 2015 and June 2018.
Results: A total of 245 TPE procedures were performed in 55 patients for nine neurological indications, predominantly the central nervous system (79%). Twenty four per cent (n=13) had category I and 73% (n=40) had category II indication (American Society for Apheresis (ASFA) 2019). Others (4%) were not in ASFA indications. Neuromyelitis optica spectrum disorders accounted for half (51%) of the total patients. Twenty-three (41.8%) patients experienced adverse events, with hypotensive episodes being the the most common (n=12/55, 21.8%). Five (9.1%) patients had catheter-related blood stream infection, correlating with higher exchange plasma volume (p=0.023). Symptomatic hypocalcaemia was less common (n=5/55, 9.1%) and allergic reaction to human albumin was rare (n=1/55, 1.8%). Four technical errors detected. Three involved centrifugation sets manufacturing defects and one involved error in centrifugation set installation. Seven (2.9%) procedures were terminated: 5 for adverse effects and 2 for technical errors.
Conclusion: Performing TPE among semi-critical patients with neurology manifestations in basic non-acute set-up proved safe, with predictable complications. This set-up reduced the reliance on critical care services for TPE procedures.

Matched MeSH terms: Centrifugation
Fulltext Risk Factors and Severity of Gastrointestinal Parasites in Selected Small Ruminants from Malaysia

Paul BT, Jesse FFA, Chung ELT, Che'Amat A, Mohd Lila MA

Vet Sci, 2020 Dec 18;7(4).
PMID: 33353135 DOI: 10.3390/vetsci7040208

The productivity of smallholder sheep and goat flocks is constrained by high morbidity and mortality of young stock due to helminthosis and coccidiosis. We hypothesized that gastrointestinal parasites are prevalent and may cause severe infections amongst small ruminants in Malaysia. A cross-sectional survey was conducted between March and December 2019 to investigate the prevalence, risk factors, and levels of infection with gastrointestinal strongyle and coccidia in selected smallholder goat flocks in Negeri Sembilan, Malaysia. A total of 257 blood and fecal samples and management data were collected from four farms in Negeri Sembilan. Gastrointestinal parasites were detected by routine sodium chloride floatation, and the McMaster technique was used to quantify the fecal eggs/oocysts per gram outputs (EPG/OPG). The severity of infection was classified as mild (50-799), moderate (800-1200), or severe (>1200). The packed cell volume (PCV) was determined by microhematocrit centrifugation and classified as anemic or non-anemic. Coprological examination revealed an overall prevalence of 78.6% (CI = 72.74-83.44) and 100% flock level prevalence of strongyle and coccidia infection among goats from Negeri Sembilan with a higher infection in flock A-Lenggeng (95.6%) than B-Senawang (87.3%), D-Mendom (80.6%), or C-Seremban (60.0%). The co-infections of strongyle + Eimeria (50.6; CI = 44.50 to 56.64) were more common than single infections of either strongyle (16.7%; CI = 12.66 to 21.78) or Eimeria (4.3%; CI = 2.41 to 7.50). Quantitative analysis has revealed different (p < 0.05) patterns of EPG/OPG in various categories of goats. In total, there were 49.8% mild, 8.6% moderate, and 13.6% severe infections of strongyle and 40.1% mild, 6.6% moderate, and 19.8% severe infections of coccidia among goats. The mean PCV of goats with severe strongyle infection (24.60 ± 0.85) was significantly (p < 0.05) lower than the moderate (26.90 ± 1.15), or mild (28.23 ± 0.50) infections and the uninfected (30.4 ± 0.71). There were increased odds of infection with strongyle and coccidia among female (OR = 3.2) and adult (OR = 11.0) goats from smallholder flocks in Negeri Sembilan. In conclusion, gastrointestinal strongyles and coccidia occur at high frequency among smallholder goats, and there is a higher risk of infection amongst the adult and female stock.

Matched MeSH terms: Centrifugation
A pseudo-cryptococcal artefact derived from leucocytes in wet India ink mounts of centrifuged cerebrospinal fluid

Thiruchelvan N, Wuu KY, Arseculeratne SN, Ashraful-Haq J

J Clin Pathol, 1998 Mar;51(3):246-8.
PMID: 9659271

Wet India ink mounts of cerebrospinal fluid (CSF) are useful in the laboratory diagnosis of cryptococcal meningitis. Pseudo-cryptococcal artefacts in such mounts have been attributed to leucocytes in CSF but their mode of formation has not been explained. This report describes the reproduction of such an artefact in cryptococcus free CSF-leucocyte mixtures that had been subjected to high speed centrifugation. The viscosity of DNA that could provide a morphological pseudo-capsule, and the yellow-green fluorescence of the pseudo-capsular material on staining with acridine-orange, suggest that lymphocytic nuclear DNA, which possibly leaked out after damage to the lymphocyte membrane by centrifugation, was responsible for this artefact.

Matched MeSH terms: Centrifugation
Fulltext Properties of proteolytic enzyme from ginger (Zingiber officinale Roscoe)

Nafi’, A., Foo, H.L., Jamilah, B., Ghazali. H.M.

International Food Research Journal, 2013;20(1):363-368.
MyJurnal

Proteases in ginger rhizome have the potentials in industrial applications. This study was conducted to extract and characterize the proteolytic enzyme from ginger (Zingiber officinale Roscoe). Ginger protease (GP) was extracted from ginger rhizome by homogenization with 100 mM potassium phosphate buffer pH 7.0 containing 10 mM cysteine and 5 mM EDTA which were found to be the most efficient extraction buffer and stabilizers. After centrifugation at 10,500 x g, protein in the crude extract was precipitated using 60% ammonium sulfate following which the precipitate was redissolved in 50 mM potassium phosphate buffer pH 7.0, dialyzed and then lyophilized. The extraction method yielded 0.94% (w/w of fresh weight) of GP with a specific activity of 27.6 ± 0.1 Unit/mg protein where 1 Unit is defined as the amount of protease causing an increase in absorbance by 1 unit per minute using azocasein as the substrate. Results show that the GP was completely inhibited by heavy metal cations i.e. Cu2+and Hg2+, and a thiol blocking agent or inhibitor, n-ethyl maleimide (NEM), indicating that GP is most probably a cysteine protease. The enzyme has an optimum temperature at 60⁰C and the optimum pH ranged between pH 6 to 8. Monovalent cations (K+ and Na+) have no significant effect on activity of GP, but divalent and trivalent cations showed moderate inhibitory effect. Detergents such as sodium dodecyl sulfate increased the activity of GP while Tween 80 and Tween 20 slightly reduced the activity.

Matched MeSH terms: Centrifugation
Fulltext The effect of human mesenchymal stem cell on neutrophil oxidative burst

Ramasamy, R., Krishna, K., Maqbool, M., Vellasamy, S., Sarmadi, V. H., Abdullah, M., et al.

Malaysian Journal of Medicine and Health Sciences, 2010;6(2):11-17.
MyJurnal

Objective: Mesenchymal stem cells (MSC) are multipotent, non-haematopoietic stem cells that are
capable of differentiating into different varieties of mature cell types such as osteoblasts, chondrocytes, adipocytes, and myoblasts. There is abundant evidence showing that MSC not only affect the differentiation of haematopoietic progenitors, but also the function of mature cells like lymphocytes and neutrophils. However the effect of MSC on neutrophil function and its responses is not well studied. Therefore, this study was conducted to assess the effect of MSC on neutrophil nitric oxide production. Method: Neutrophils from heparanised venous blood were isolated using Ficoll-Hypaque density gradient centrifugation followed by Dextran sedimentation and red blood cell (RBC) lysis. Isolated neutrophils were on average of 97% purity as determined by morphologic analysis. MSC were generated from human bone marrow and characterised by immunophenotyping (monoclonal antibodies CD105, CD73 and CD34) using a flowcytometer. In order to test the effects of MSC on neutrophil function, isolated neutrophils were co-cultured in the presence or absence of MSC at different ratios for 24 and 48 hours. The amount of nitric oxide released was used as an indication of oxidative burst and measured using the Griess assay. Result: The results indicate that MSC neither elevate the NO level when cocultured with resting neutrophils nor alone. However MSC profoundly inhibit the secretion of nitric oxide in PMA stimulated neutrophils after 24hr of incubation. Conclusion: MSC exert an immunomodulatory effect on neutrophil by suppressing neutrophil oxidative burst in vitro.

Matched MeSH terms: Centrifugation, Density Gradient
Fulltext Stability Evaluations of Different Types of Vegetable Oil-based Emulsions

Teh SS, Mah SH

J Oleo Sci, 2018;67(11):1381-1387.
PMID: 30404958 DOI: 10.5650/jos.ess18067

The study was aimed at evaluating the effects of vegetable oils on emulsion stability. Palm olein (POo), olive oil (OO), safflower oil (SAF), grape seed oil (GSO), soybean oil (SBO) and sunflower oil (SFO) with different degree of saturation levels were chosen as major ingredient of oil phases. All the emulsions were stored at 4℃, 27℃ and 40℃ for 35 days and subjected to all the stability tests, including temperature variation, centrifuge test, cycle test, pH and slip melting point. The results indicated that POo exhibited the highest stability, followed by SAF, OO, GSO, SFO and SBO. In addition, the results implied that the degree of saturation levels of vegetable oils does give significant effect on emulsion stability based on the centrifuge testing for an approximate 30% usage level of oil. The POo-based emulsion exhibited good emulsion stability throughout the experimental period indicated that POo could be a good carrier oil for various applications in cosmetic industry.

Matched MeSH terms: Centrifugation
Purification of bacteriophage M13 by anion exchange chromatography

Monjezi R, Tey BT, Sieo CC, Tan WS

J Chromatogr B Analyt Technol Biomed Life Sci, 2010 Jul 1;878(21):1855-9.
PMID: 20538529 DOI: 10.1016/j.jchromb.2010.05.028

M13 is a non-lytic filamentous bacteriophage (phage). It has been used widely in phage display technology for displaying foreign peptides, and also for studying macromolecule structures and interactions. Traditionally, this phage has been purified by cesium chloride (CsCl) density gradient ultracentrifugation which is highly laborious and time consuming. In the present study, a simple, rapid and efficient method for the purification of M13 based on anion exchange chromatography was established. A pre-packed SepFast Super Q column connected to a fast protein liquid chromatography (FPLC) system was employed to capture released phages in clarified Escherichia coli fermented broth. An average yield of 74% was obtained from a packed bed mode elution using citrate buffer (pH 4), containing 1.5 M NaCl at 1 ml/min flow rate. The purification process was shortened substantially to less than 2 h from 18 h in the conventional ultracentrifugation method. SDS-PAGE revealed that the purity of particles was comparable to that of CsCl gradient density ultracentrifugation method. Plaque forming assay showed that the purified phages were still infectious.

Matched MeSH terms: Centrifugation, Density Gradient
Fulltext New insights of phenolic compounds from optimized fruit extract of Ficus auriculata

Shahinuzzaman M, Akhtar P, Amin N, Ahmed Y, Anuar FH, Misran H, et al.

Sci Rep, 2021 Jun 14;11(1):12503.
PMID: 34127747 DOI: 10.1038/s41598-021-91913-w

In this study, the extraction conditions extracted maximize amounts of phenolic and bioactive compounds from the fruit extract of Ficus auriculata by using optimized response surface methodology. The antioxidant capacity was evaluated through the assay of radical scavenging ability on DPPH and ABTS as well as reducing power assays on total phenolic content (TPC). For the extraction purpose, the ultrasonic assisted extraction technique was employed. A second-order polynomial model satisfactorily fitted to the experimental findings concerning antioxidant activity (R2 = 0.968, P

Matched MeSH terms: Centrifugation
Effect of Gibberellin and Heat Shock on the Lipid Composition of Endoplasmic Reticulum in Barley Aleurone Layers

Grindstaff KK, Fielding LA, Brodl MR

Plant Physiol, 1996 Feb;110(2):571-581.
PMID: 12226205

The heat-shock responses of barley (Hordeum vulgare L. cv Hi- malaya) aleurone layers incubated with or without gibberellic acid (GA3) were compared. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that heat shock blocked the synthesis and secretion of secretory proteins from GA3-treated layers but not untreated layers. This suppression of secretory protein synthesis has been correlated with changes in endoplasmic reticulum (ER) membranes (F.C. Belanger, M. R. Brodl, T.-h.D. Ho [1986] Proc Natl Acad Sci USA 83: 1354-1358; L. Sticher, A.K. Biswas, D.S. Bush, R.L. Jones [1990] Plant Physiol 92: 506-513). Our secretion data suggested that the ER membranes of aleurone layers incubated without GA3 may be more heat shock tolerant. To investigate this, the lipid profiles of membrane extracts in aleurone layers labeled with [14C]glycerol were examined. Heat shock markedly increased [14C]glycerol incorporation into phosphatidylcholine (PC), and gas chromatography revealed an increase in the amount of saturated fatty acids associated with thin layer chromatography-purified PC in GA3-treated layers. In contrast, aleurone layers incubated without GA3 at normal temperature contained PC-associated fatty acids with a greater degree of saturation than GA3-treated layers. Heat shock modestly increased the degree of fatty acid saturation in untreated aleurone layers. This same trend was noted in fatty acids isolated from ER membranes purified by continuous sucrose density centrifugation. We propose that increased fatty acid saturation may help sustain ER membrane function in heat-shocked aleurone layers incubated in the absence of GA3.

Matched MeSH terms: Centrifugation
Tests on the centrifugal flotation technique and its use in estimating the prevalence of Toxocara in soil samples from urban and suburban areas of Malaysia

Loh AG, Israf DA

J Helminthol, 1998 Mar;72(1):39-42.
PMID: 9639899

The influence of soil texture (silt, sand and laterite) and flotation solutions (saturated NaCl, sucrose, NaNO3, and ZnSO4) upon the recovery of Toxocara ova from seeded soil samples with the centrifugal flotation technique was investigated. Soil samples of different texture were artificially seeded with Toxocara spp. ova and subjected to a centrifugal flotation technique which used various flotation solutions. The results showed significant (P < 0.001) interactions between the soil types and the flotation solutions. The highest percentage of ova recovery was obtained with silty soil (34.9-100.8%) with saturated NaCl as the flotation solution (45.3-100.8%). A combination of washing of soil samples with 0.1% Tween 80, and flotation using saturated NaCl and a 30 min coverslip recovery period was used to study the prevalence of contamination of soil samples. Forty-six soil samples were collected from up to 24 public parks/playgrounds in urban areas of Petaling Jaya and suburban areas of Serdang. The prevalence of Toxocara species in the urban and suburban areas was 54.5% and 45.8% respectively.

Matched MeSH terms: Centrifugation, Density Gradient
The wound healing properties of Channa striatus-cetrimide cream-- tensile strength measurement

Baie SH, Sheikh KA

J Ethnopharmacol, 2000 Jul;71(1-2):93-100.
PMID: 10904151

Channa striatus, a fresh water snakehead fish, is reported to enhance dermal wound healing. Biochemical components such as amino acids and fatty acids are important for the synthesis of collagen fibers during wound healing. Arachidonic acid, a precursor of prostaglandin plays a vital role in healing the wounds. Haruan (C. striatus) contains all the essential amino acids for wound healing particularly glycine as well as high contents of arachidonic acid and polyunsaturated fatty acids that can promote prostaglandin synthesis. In the present work we have studied the wound healing effect of C. striatus in Sprague-Dawley rats. Cream formulations having different haruan fish extract concentrations as the active ingredient were prepared and stabilized, and they were applied to the wounds. The healing of wounds was characterized by an increase in the tensile strength of the skin, determined on the 7th post-operative day in each case. Haruan treatment of wounds promotes remodeling of collagen, by the synthesis of inter- and intra-molecular protein crosslinking and thus produces a marked increase (P<0.05) in tensile strength as compared to the cetrimide treated group. On the basis of our experiment we conclude that C. striatus helps in wound healing as indicated by the increase in tensile strength. We hypothesise that this effect may be due to its high content of arachidonic acid, glycine and polyunsaturated fatty acids. The mechanism of wound healing will be investigated in future studies.

Matched MeSH terms: Centrifugation
Purification of His-tagged hepatitis B core antigen from unclarified bacterial homogenate using immobilized metal affinity-expanded bed adsorption chromatography

Yap WB, Tey BT, Alitheen NB, Tan WS

J Chromatogr A, 2010 May 21;1217(21):3473-80.
PMID: 20388569 DOI: 10.1016/j.chroma.2010.03.012

Hepatitis B core antigen (HBcAg) is used as a diagnostic reagent for the detection of hepatitis B virus infection. In this study, immobilized metal affinity-expanded bed adsorption chromatography (IMA-EBAC) was employed to purify N-terminally His-tagged HBcAg from unclarified bacterial homogenate. Streamline Chelating was used as the adsorbent and the batch adsorption experiment showed that the optimal binding pH of His-tagged HBcAg was 8.0 with a binding capacity of 1.8 mg per ml of adsorbent. The optimal elution condition for the elution of His-tagged HBcAg from the adsorbent was at pH 7 in the presence of 500 mM imidazole and 1.5 M NaCl. The IMA-EBAC has successfully recovered 56% of His-tagged HBcAg from the unclarified E. coli homogenate with a purification factor of 3.64. Enzyme-linked immunosorbent assay (ELISA) showed that the antigenicity of the recovered His-tagged HBcAg was not affected throughout the IMA-EBAC purification process and electron microscopy revealed that the protein assembled into virus-like particles (VLP).

Matched MeSH terms: Centrifugation, Density Gradient

Filters

Please provide feedback to Administrator ([email protected])

External Links