Displaying publications 1 - 20 of 45 in total

  1. Yusof, F., Faruck, M.O., Chowdhury, S.
    Antifungal peptides have been successfully extracted from whole body larvae of Zophobas morio (Fabricius) by using acidified isopropanol. To ensure that the extraction is cost effective for maximum yield, Response Surface Methodology (RSM) using a Central Composite Design (CCD) strategy was adopted to optimize the extraction process parameters. The effect of independent parameters, namely, the homogenization temperature (°C), homogenization time (min) and solid (g) to the solvent (ml) ratio of the extraction process on the fungal growth was studied. The extracted samples obtained by conducting runs accorded by the experimental design showed varying degree of antifungal activity against Aspergillus niger, the selected fungal strain, as assayed by the ‘‘Poisoned agar technique’. The investigation showed that the optimum values of the extraction parameters for the maximum antifungal peptides were 5 minutes homogenization time, 4°C homogenization temperature and 3.5:1 solid to solvent ratio. This study reports the development of an extraction process that allows careful recovery of antifungal peptides from larvae. In the validation of the experimental model, the error between the actual value and the predicted value was determined to be 3.57%.
  2. Faruck, M.O.,, Yusof, F., Chowdhury, S.
    Acidified isopropanol extract of whole body larvae of Zophobas morio (Fabricius), which contains peptides, has been shown to exhibit an inhibitory effect towards fungal growth. The larvae, commonly known as supermeal worm are cheap and easily maintained. To make the extraction even more cost effective, it is pertinent to maximize the extraction yield and to optimize the extraction process. The aim of this study is to use the One-Factor-At-a-Time (OFAT) strategy to determine the maximum values of the process parameters for the extraction of antifungal peptides, where these values can later be used in the experimental design to optimize the extraction process. Based on importance, three parameters were selected, namely, initial homogenization temperature, homogenization time and solid (g) to solvent (ml) ratio. Maximum inhibition to fungal growth was found when the extraction was carried out as follows; using initial homogenization temperature of 4°C, homogenization time of 5 minutes and a solid (g) to solvent (ml) ratio of 3.5:1. The peptide extract displayed different degree of antifungal effect towards four selected fungi, Aspergillus niger, Microsporum canis, Candida albicans and Blastomyces dermatitidsis.
  3. Easa, M.N., Yusof, F., Abd. Halim, A.
    Cross-Linked Enzyme Aggregates (CLEA) is known as one of the best enzyme immobilization technique nowadays. In this study, amylase extract from Zophobas morio (super mealworm) larvae was immobilized using acetone as the precipitant, glutaraldehyde as the cross-linker and bovine serum albumin as the additive. The characteristics of the produced CLEA were compared to the free soluble amylase, in terms of pH and temperature optimum and stabilities. The results displayed that CLEAand free amylase achieved an optimum temperature at 55°C and 45°C, respectively. CLEA-amylase also had showed greater stability against high temperature as compared to a free enzyme which had lost most of its activity when the temperature was set beyond 45°C. In comparison, at 65°C, CLEA-amylase still retained 73.2% of its activity. Results also revealed that CLEA-amylase has a pH optimum at 11, while it is pH 7 for free enzyme. Similarly, CLEA-amylase was more stable than the free form, over a wider range of pH, particularly at higher pH of 9, 10 and 11. Recyclability study showed that CLEA-amylase could retain 14.9% of its residual activity after 6 times of repeated uses. Since it is reusable, future works might include the evaluations of using CLEA-amylase at the industrial level, remarkably in detergent applications.
  4. Easa M.N., Yusof, F., Abd. Halim, A.
    Many studies have been done on various species of insects to investigate their potential use in industries. This is because insects have high protein content which could be further manipulated. Due to its eating habit, Zophobas morio larvae, also known as super mealworm has been shown to have high amylase activity. In this study, amylase from super mealworm has been immobilized via Cross-Linked Enzyme Aggregates (CLEA) technique and its kinetic performance, evaluated. CLEA is one of the best immobilization method with respect to enzyme stability and reusability. Kinetic performance of both free and CLEA-amylase were evaluated based on the Michaelis-Menten model. Results obtained based on Hanes-Woolf, LineweaverBurk, Eadie-Hofstee and Hyperbolic Regression plots showed that the kinetic parameters, Vmax and KM, changed upon immobilization. For CLEA-amylase, Hanes-Woolf plot showed the bestfitted model based on R2 with Vmax= 1.068 mM/min and KM= 0.182 mM, however, LineweaverBurk plot was used to obtain the kinetic parameters for free amylase, with Vmax and KM of 17.230 mM/min and 2.470 mM, respectively. Thus it is observed that upon immobilization, Vmax for amylase dropped appreciably, however, much lower substrate concentration is needed to saturate the enzymatic sites to reach its maximum catalytic efficiency. The result from this study might open the new path in discovering the potential use of insects in industrial applications, for example, making use of the recovered enzymes in the detergent industry.
  5. Yusof, F., Chowdhury, S., Faruck, M. O., Sulaiman, N.
    Cancer still presents enormous challenges in the medical world. Currently, the search for
    anticancer compounds has garnered a lot of interest, especially in finding them from the natural
    sources. In this study, by using Sulforhodamine B (SRB) colorimetric assay, compounds,
    extracted from supermeal worm (Zophobas morio) larvae using two types of acidified organic
    solvent (ethanol and isopropanol), were shown to inhibit the growth of a breast cancer line,
    MCF-7. A comparative study of the effect was carried out on a normal cell line, Vero. Results
    showed that, the two types of extracts inhibits growth of MCF-7 cell at varying degrees, on
    the other hand, have much less effect on Vero cell. Extracts analysed by UV-vis spectroscopy,
    showed peaks in the range of 260 to 280 nm, inferring the presence of aromatic amino acids,
    whereas the highest peak of 3.608 AU at 230 nm indicates the presence of peptide bonds. By
    Raman spectroscopy, peaks are observed at 1349 cm-1, 944 cm-1 and 841 cm-1 indicating the
    presence of Tyr, Try and Gly, confirming the UV-vis analyses. All results of analyses implied
    that the anticancer compounds contain peptides.
  6. Yusof, F. M., Md. Ismail, A. I. B., Abu Hasan, Y.
    MATEMATIKA, 2018;34(2):205-226.
    Hantaviruses are etiological agents of zoonotic diseases and certain other dis-
    eases, which pose a serious threat to human health. When rodent and predator popula-
    tions share in an ecology, the competitive force of the populations can lead to a reduction
    or elimination of a hantavirus outbreak. The effect of the predator eliminating rodents
    and predator populations that tends to reduce or eliminate hantavirus infection is investi-
    gated. The existence of several equilibrium points of the model is identified and local and
    global stabilities of the model at these equilibrium points are analysed in detail. Numerical
    simulations are carried out to illustrate our model results.
  7. Mahmud, I.A., Mirghani, M.E.S., Alkhatib, M.F.R., Yusof, F., Shahabuddin, M., Rashidi, O., et al.
    Phoenix dactylifera L (Date palm) is one of the oldest known fruit crops in the world, and
    the consumption of date fruits is no longer restricted to the Middle Eastern countries. Date
    palm kernels are waste products of date fruit industry which are normally being discarded.
    Based on their dietary fiber content; date palm kernels (DPK) have been proposed to be used
    as fiber-based food supplement, caffeine free coffee alternative and animal feed ingredient.
    Hence, utilization of such waste is highly desirable for the date industry. To accommodate these
    benefits, and subsequent to some uses associated with DPK, this study sought to investigate the
    biochemical and nutritional values of the Barhi date palm kernels (BDPK) grown in Iraq. The
    results show that BDPK is an excellent source of dietary fiber (66.24 g/100g). Glutamic acid
    was found to be the predominant amino acid, (0.674 g/100g), followed by Arginine and aspartic
    acid (0.437 g/100g and 0.320 g/100g, respectively). Potassium was the most occurring mineral
    in BDPK (2.39 g/kg), and the main sugars were sucrose and fructose (0.548 g/100g and 0.249
    g/100g, respectively). Gas-liquid chromatography revealed that the main unsaturated fatty acid
    (USFA) was oleic acid (40.927 mg/100g), while the main saturated fatty acid (SFA) were lauric
    acid (20.270 mg/100g) and myristic acid (12.288 mg/100g). Furthermore, the BDPK depicted
    considerable concentrations of vitamins, in which vitamin B5 (40.4 mg/100g) showed the
    highest value. The results obtained indicate a strong potential for BDPK to be used in human
    nutrition, cosmetics, and pharmaceutical applications and may provide an important economic
    advantage through increasing the utilization of BDKP while also additive value will be added
    to the residue.
  8. Yeang HY, Yusof F, Abdullah L
    Anal Biochem, 1995 Mar 20;226(1):35-43.
    PMID: 7785777
    Many proteins derived from the latex of Hevea brasiliensis that remain soluble in trichloroacetic acid (TCA) can be precipitated by phosphotungstic acid (PTA). A combination of 5% TCA and 0.2% PTA precipitates a wide range of proteins effectively even when they are present in low concentrations (below 1 microgram ml-1). In addition to its protein purification function, acid precipitation also increases the sensitivity of the subsequent protein assay by allowing the test sample to be concentrated. Another advantage of protein precipitation by TCA and PTA is that very small amounts of protein (of the order of 10 micrograms) can be repeatably recovered without the use of precipitate-bulking agents such as sodium deoxycholate. This general procedure of protein purification and concentration is simple and rapid, but the use of PTA may not be fully compatible with the Bradford protein assay. A modified Lowry microassay is described which enables about 3 micrograms ml-1 to be quantitated at the photometric absorbance of 0.05. When used in conjunction with protein concentration by precipitating with TCA/PTA, approximately 0.4 microgram ml-1 protein present in 6 ml of solution can be assayed.
  9. Taha, H., Mohebali, N., Chung, Y. L., Ismail, N. H., Aziz , A., Bakar, M. Z. A., et al.
    his is a short report on the recent investigation on the anticancer and antioxidant potential
    of Pseuduvaria macrophylla stem bark and leaf extract on human breast cancer cell (MCF-7), human
    prostate cancer cell (PC-3) and human colon cancer cell (HT29). LCMS experiment was done to
    identify the chemical composition in the methanolic extracts while GCMS analysis was done to
    determine the chemical composition in the hexanolic extracts. For antioxidant activity, the most active
    extract was leaf methanolic with 69.22 % of DPPH inhibition. Additionally, the leaf methanolic extract
    inhibited the better proliferation especially on human breast cancer cell (MCF-7) compared to hexane
    crude extracts due to more than 90% of cancer cell death and lowest IC50 value at range of 80.70
    µg/mL ± 0.08 – 106.70 µg/mL ± 0.07. The major detected compounds were α-Cadinol, neophytadiene,
    palmitic acid, linoleic acid, oleic acid and isopolycerasoidal and isopolycerasoidal methyl ester. The
    findings of this study support the anti-cancer claims of Pseuduvaria macrophylla leaf. Copyright© 2016
    Penerbit Akademia Baru- All rights reserved.
  10. Yakubu ML, Yusop Z, Yusof F
    ScientificWorldJournal, 2014;2014:361703.
    PMID: 25126597 DOI: 10.1155/2014/361703
    This paper presents the modelled raindrop size parameters in Skudai region of the Johor Bahru, western Malaysia. Presently, there is no model to forecast the characteristics of DSD in Malaysia, and this has an underpinning implication on wet weather pollution predictions. The climate of Skudai exhibits local variability in regional scale. This study established five different parametric expressions describing the rain rate of Skudai; these models are idiosyncratic to the climate of the region. Sophisticated equipment that converts sound to a relevant raindrop diameter is often too expensive and its cost sometimes overrides its attractiveness. In this study, a physical low-cost method was used to record the DSD of the study area. The Kaplan-Meier method was used to test the aptness of the data to exponential and lognormal distributions, which were subsequently used to formulate the parameterisation of the distributions. This research abrogates the concept of exclusive occurrence of convective storm in tropical regions and presented a new insight into their concurrence appearance.
  11. Amid A, Samah NA, Yusof F
    Proteome Sci, 2012;10(1):1.
    PMID: 22230661 DOI: 10.1186/1477-5956-10-1
    In this study, proteomics methods have been used to study the effects of different currents and voltages used to stun chickens. Protein profiles of chicken hearts were constructed to detect differences in protein expression and modification. The different voltages studied were 10 V, 40 V and 70 V, while the currents examined were 0.25 A, 0.5 A, and 0.75 A. The profiles obtained from these stunning conditions were compared to the non-stunned (0 A, 0 V) sample.
  12. Faruck MO, Yusof F, Chowdhury S
    Peptides, 2016 06;80:80-88.
    PMID: 26093218 DOI: 10.1016/j.peptides.2015.06.001
    Fungi are not classified as plants or animals. They resemble plants in many ways but do not produce chlorophyll or make their own food photosynthetically like plants. Fungi are useful for the production of beer, bread, medicine, etc. More complex than viruses or bacteria; fungi can be destructive human pathogens responsible for various diseases in humans. Most people have a strong natural immunity against fungal infection. However, fungi can cause diseases when this immunity breaks down. In the last few years, fungal infection has increased strikingly and has been accompanied by a rise in the number of deaths of cancer patients, transplant recipients, and acquired immunodeficiency syndrome (AIDS) patients owing to fungal infections. The growth rate of fungi is very slow and quite difficult to identify. A series of molecules with antifungal activity against different strains of fungi have been found in insects, which can be of great importance to tackle human diseases. Insects secrete such compounds, which can be peptides, as a part of their immune defense reactions. Active antifungal peptides developed by insects to rapidly eliminate infectious pathogens are considered a component of the defense munitions. This review focuses on naturally occurring antifungal peptides from insects and their challenges to be used as armaments against human diseases.
  13. Tan AT, Tan AW, Yusof F
    Ultrason Sonochem, 2017 01;34:616-625.
    PMID: 27773288 DOI: 10.1016/j.ultsonch.2016.06.039
    Techniques to improve solder joint reliability have been the recent research focus in the electronic packaging industry. In this study, Cu/SAC305/Cu solder joints were fabricated using a low-power high-frequency ultrasonic-assisted reflow soldering approach where non-ultrasonic-treated samples were served as control sample. The effect of ultrasonic vibration (USV) time (within 6s) on the solder joint properties was characterized systematically. Results showed that the solder matrix microstructure was refined at 1.5s of USV, but coarsen when the USV time reached 3s and above. The solder matrix hardness increased when the solder matrix was refined, but decreased when the solder matrix coarsened. The interfacial intermetallic compound (IMC) layer thickness was found to decrease with increasing USV time, except for the USV-treated sample with 1.5s. This is attributed to the insufficient USV time during the reflow stage and consequently accelerated the Cu dissolution at the joint interface during the post-ultrasonic reflow stage. All the USV-treated samples possessed higher shear strength than the control sample due to the USV-induced-degassing effect. The shear strength of the USV-treated sample with 6s was the lowest among the USV-treated samples due to the formation of plate-like Ag3Sn that may act as the crack initiation site.
  14. Ting Tan A, Wen Tan A, Yusof F
    Sci Technol Adv Mater, 2015 Jun;16(3):033505.
    PMID: 27877786
    Nanocomposite lead-free solders are gaining prominence as replacements for conventional lead-free solders such as Sn-Ag-Cu solder in the electronic packaging industry. They are fabricated by adding nanoparticles such as metallic and ceramic particles into conventional lead-free solder. It is reported that the addition of such nanoparticles could strengthen the solder matrix, refine the intermetallic compounds (IMCs) formed and suppress the growth of IMCs when the joint is subjected to different thermal conditions such as thermal aging and thermal cycling. In this paper, we first review the fundamental studies on the formation and growth of IMCs in lead-free solder joints. Subsequently, we discuss the effect of the addition of nanoparticles on IMC formation and their growth under several thermal conditions. Finally, an outlook on the future growth of research in the fabrication of nanocomposite solder is provided.
  15. Yousof Y, Salleh NM, Yusof F
    J Prosthet Dent, 2019 Jun;121(6):916-921.
    PMID: 30745100 DOI: 10.1016/j.prosdent.2018.09.005
    STATEMENT OF PROBLEM: The 2-color mixing ability test has been recently introduced for objective assessment of masticatory performance. However, the ideal bicolor specimens have not yet been identified, and the color analysis of digital images requires improvement.

    PURPOSE: The purpose of this clinical study was to formulate a custom-made, 2-color chewing gum for the mixing ability test and to develop an image-processing method for color mixing analysis.

    MATERIAL AND METHODS: Specimens of red-green (RG) chewing gum were prepared as a test food. Twenty dentate participants (10 men, 10 women; mean age 21 years) took part in this study. Each participant masticated 1 piece of RG gum for 3, 6, 9, 15, and 25 cycles, and this task was repeated 3 times consecutively (total n=15 for each participant). The boluses were retrieved and flattened to 1-mm-thick wafers and scanned with a flatbed scanner. The digital images were analyzed using ImageJ software equipped with a custom-built plug-in to measure the geometric dispersion (GD) of baseline red segment. The predictive criterion validity of this method was determined by correlating GD to the number of mastication cycles. The hardness and mass of RG chewing gum were measured before and after mastication. Hardness loss (%) and mass loss (%) were then calculated and compared with those of a commercially available chewing gum.

    RESULTS: The 2-way repeated-measures ANOVA with post hoc Bonferroni test showed that GD was able to discriminate among the groups of different numbers of mastication cycles (P

  16. Shahruzaman SH, Yusof FZ, Maniam S, Fakurazi S, Maniam S
    BMC Complement Med Ther, 2021 Oct 01;21(1):245.
    PMID: 34598696 DOI: 10.1186/s12906-021-03417-9
    BACKGROUND: Adaptive metabolic response towards a low oxygen environment is essential to maintain rapid tumour proliferation and progression. The vascular network that surrounds the tumour develops an intermittent hypoxic condition and stimulates hypoxia-inducing factors. Baeckea frutescens is used in traditional medicine and known to possess antibacterial and cytoprotective properties. In this study, the cytotoxic effect of B. frutescens leaves and branches extracts against hypoxic human breast cancer (MCF-7) was investigated.

    METHOD: The extracts were prepared using Soxhlet apparatus for ethanol and hexane extracts while the water extracts were freeze-dried. In vitro cytotoxic activities of B. frutescens extracts of various concentrations (20 to 160 μg/mL) at 24, 48, and 72 hours time points were studied using MTT in chemically induced hypoxic condition and in 3-dimensional in vitro cell culture system. An initial characterisation of B. frutescens extracts was carried out using Fourier-transform Infrared- Attenuated Total Reflection (FTIR-ATR) to determine the presence of functional groups.

    RESULTS: All leaf extracts except for water showed IC50 values ranging from 23 -158 μg/mL. Hexane extract showed the lowest IC50 value (23 μg/mL), indicating its potent cytotoxic activity. Among the branch extracts, only the 70% ethanolic extract (B70) showed an IC50 value. The hexane leaf extract tested on 3- dimensional cultured cells showed an IC50 value of 17.2 μg/mL. The FTIR-ATR spectroscopy analysis identified various characteristic peak values with different functional groups such as alcohol, alkenes, alkynes, carbonyl, aromatic rings, ethers, ester, and carboxylic acids. Interestingly, the FTIR-ATR spectra report a complex and unique profile of the hexane extract, which warrants further investigation.

    CONCLUSION: Adaptation of tumour cells to hypoxia significantly contributes to the aggressiveness and chemoresistance of different tumours. The identification of B. frutescens and its possible role in eliminating breast cancer cells in hypoxic conditions defines a new role of natural product that can be utilised as an effective agent that regulates metabolic reprogramming in breast cancer.

  17. Yusof F, Sha'ban M, Azhim A
    Int J Nanomedicine, 2019;14:5491-5502.
    PMID: 31410000 DOI: 10.2147/IJN.S207270
    PURPOSE: Meniscus is a fibrocartilagenous tissue that cannot effectively heal due to its complex structure and presence of avascular zone. Thus, tissue engineering and regenerative medicine offer an alternative for the regeneration of meniscus tissues using bioscaffolds as a replacement for the damaged one. The aim of this study was to prepare an ideal meniscus bioscaffold with minimal adverse effect on extracellular matrix components (ECMs) using a sonication treatment system.

    METHODS: The decellularization was achieved using a developed closed sonication treatment system for 10 hrs, and continued with a washing process for 5 days. For the control, a simple immersion treatment was set as a benchmark to compare the decellularization efficiency. Histological and biochemical assays were conducted to investigate the cell removal and retention of the vital extracellular matrix. Surface ultrastructure of the prepared scaffolds was evaluated using scanning electron microscope at 5,000× magnification viewed from cross and longitudinal sections. In addition, the biomechanical properties were investigated through ball indentation testing to study the stiffness, residual forces and compression characteristics. Statistical significance between the samples was determined with p-value =0.05.

    RESULTS: Histological and biochemical assays confirmed the elimination of antigenic cellular components with the retention of the vital extracellular matrix within the sonicated scaffolds. However, there was a significant removal of sulfated glycosaminoglycans. The surface histoarchitecture portrayed the preserved collagen fibril orientation and arrangement. However, there were minor disruptions on the structure, with few empty micropores formed which represented cell lacunae. The biomechanical properties of bioscaffolds showed the retention of viscoelastic behavior of the scaffolds which mimic native tissues. After immersion treatment, those scaffolds had poor results compared to the sonicated scaffolds due to the inefficiency of the treatment.

    CONCLUSION: In conclusion, this study reported that the closed sonication treatment system had high capabilities to prepare ideal bioscaffolds with excellent removal of cellular components, and retained extracellular matrix and biomechanical properties.

  18. Zainal-Abideen M, Aris A, Yusof F, Abdul-Majid Z, Selamat A, Omar SI
    Water Sci Technol, 2012;65(3):496-503.
    PMID: 22258681 DOI: 10.2166/wst.2012.561
    In this study of coagulation operation, a comparison was made between the optimum jar test values for pH, coagulant and coagulant aid obtained from traditional methods (an adjusted one-factor-at-a-time (OFAT) method) and with central composite design (the standard design of response surface methodology (RSM)). Alum (coagulant) and polymer (coagulant aid) were used to treat a water source with very low pH and high aluminium concentration at Sri-Gading water treatment plant (WTP) Malaysia. The optimum conditions for these factors were chosen when the final turbidity, pH after coagulation and residual aluminium were within 0-5 NTU, 6.5-7.5 and 0-0.20 mg/l respectively. Traditional and RSM jar tests were conducted to find their respective optimum coagulation conditions. It was observed that the optimum dose for alum obtained through the traditional method was 12 mg/l, while the value for polymer was set constant at 0.020 mg/l. Through RSM optimization, the optimum dose for alum was 7 mg/l and for polymer was 0.004 mg/l. Optimum pH for the coagulation operation obtained through traditional methods and RSM was 7.6. The final turbidity, pH after coagulation and residual aluminium recorded were all within acceptable limits. The RSM method was demonstrated to be an appropriate approach for the optimization and was validated by a further test.
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links