Hanina Mohd Noor

An overview of apoptosis for computer security

Immune system is essential to human body as it protects our bodies from pathogens in an orchestrated manner. From a computational viewpoint, the immune system has much to offer by way of inspiration. Recently, there has been growing interest in the use of natural immune system as inspiration for the creation novel approaches to computational problem. This field of research is referred as Immunological Computation or Artificial Immune System. The use of artificial system computer security is an appealing concept for two reasons. Firstly, the human immune system provides human body with a high level protection from invading pathogens in robust manner. Secondly, current techniques used in computer security are not able to cope with the dynamic and increasingly complex nature of computer systems and their security. This paper introduces the concept of apoptosis for computer security. This term is borrowed from cell biology and designates the programmed cell death.

Antimicrobial Protein Produced by Lactobacillus plantarum ATCC8014 in the Presence of Cymbopogon Sp. Essential Oils

Protein production by bacteria might be increased in stressful conditions such as in the presence of antimicrobial agents. Many studies proved that antibiotics or antimicrobial agents at low concentration are able to activate or repress gene transcription process in bacteria. However, there are still few studies on potential of natural antimicrobial compounds such as Cymbopogon essential oils acting as specific chemical signal that can trigger biological functions of bacteria. Therefore, this study aims to explore the potential of natural antimicrobial compound (Cymbopogon flexuosus and Cymbopogon nardus) at low concentration in regulating proteins production by Lactobacillus plantarum ATCC8014. The bacteria cells of L. plantarum ATCC8014 are exposed to Cymbopogon essential oils at low concentration in fermentation process for 48 hours at 37°C. SDS-PAGE analysis showed that a new intracellular protein with approximate size of 40 kDa was produced by L. plantarum ATCC8014 after being enhanced with C. nardus essential oil. Besides, the intracellular proteins, each with approximate size of 85 kDa, 45 kDa and 28 kDa synthesized by L. plantarum ATCC8014 prior to inducing with C. nardus or C. flexuosus were expressed differently. Some of the intracellular proteins were highly expressed and some of the proteins were repressed based on the intensity of protein bands appeared. Hence, L. plantarum ATCC8014 in the presence of Cymbopogon essential oils at low concentration could regulate the intracellular proteins production. The isolated protein also showed antimicrobial activity against selected Gram-positive and Gram-negative bacteria.

Improvement on the Catalytic Performance Using Dual Lipases System in the Synthesis of Ferulate Esters

A novel approach of dual lipases system was successfully carried out in improving the synthesis of ferulate esters between ethyl ferulate and olive oil. Combination of Novozym 435 and Lipozyme RMIM were used as biocatalyst to improve the reaction performance. Different reaction parameters (ratio of lipases, reaction time, lipase dosage, substrate molar ratio and reaction temperature) were analyzed systematically. A high conversion of ferulate esters (85%) was obtained after 12 hrs of reaction time at optimal conditions of 1:9 w/w (Novozym 435/Lipozyme RMIM), 80 mg of lipase and 1:4 ethyl ferulate:olive oil at 60 oC.

Protein Produced by Bacillus subtilis ATCC21332 in the Presence of Cymbopogon flexuosus Essential Oil

Proteins levels produced by bacteria may be increased in stressful surroundings, such as in the presence of antibiotics. It appears that many antimicrobial agents or antibiotics, when used at low concentrations, have in common the ability to activate or repress gene transcription, which is distinct from their inhibitory effect. There have been comparatively few studies on the potential of antibiotics or natural compounds in nature as a specific chemical signal that can trigger a variety of biological functions. Therefore, this study was focusing on the effect of essential oil from Cymbopogon flexuosus in regulating proteins production by Bacillus subtilis ATCC21332. The Minimum Inhibition Concentration (MIC) of the C. flexuosus essential oil on B. subtilis was determined by using microdilution assay, resulting 1.76mg/ml. The bacteria cells were further exposed to the C. flexuosus essential oil at concentration of 0.01 MIC for 72 h. The proteins were then isolated and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Proteins profile showed that a band with approximate size of 30 kDa was appeared for the treated bacteria with C. flexuosus essential oil. Thus, B. subtilis ATCC21332 in stressful condition with the presence of C. flexuosus essential oils at low concentration could induce the protein production. The isolated protein also showed antimicrobial activity against selected Gram-positive and Gram-negative bacteria.

High Yield Synthesis of Kojic Ester Using Dual Enzymes System and their Antibacterial Activity

Enzymatic synthesis of kojic ester, a bio-based whitening agent, was successfully carried out via esterification reaction between oleic acid and kojic acid. Commercial immobilized lipases of Novozym 435 and Lipozyme RM IM were used in combination as biocatalyst in the reaction system. Various reaction parameters were chosen to optimize the reaction in order to obtain a high yield of kojic ester including the best ratio of lipases, reaction time and reaction temperature. The optimum conditions for the synthesis of kojic ester was achieved at reaction time of 12 hours, temperature of 60 οC and equal ratio of lipases to produce more than 70 % yield. Antimicrobial tests of synthesized kojic ester towards several types of bacteria via Minimum inhibitory concentration (MIC) and Minimum bactericidal concentration (MBC) analyses were also examined. The results obtained suggested that kojic ester exhibits a good bactericidal effect towards all bacteria tested such as Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Salmonella typhimurium.

Defending virus infection through extrinsic apoptosis

This paper discusses on the enhancement of the current Intrusion Detection System (IDS) based on Artificial Immune System called apoptosis. Nowadays network systems are required to be more secured since the virus is now growing stronger and more dangerous. Unfortunately, not all of the Intrusion Detection System (IDS) is effective enough to defend against viruses entering the network. In this paper, the researcherspsila propose a new enhanced IDS system that will defend the computer system from being attacked by viruses. By using apoptosis system as the basis of the enhancement, these IDS will work similar to the human defence system and solve the problem of the virus infection in the computer system. In addition, the researcherspsila have also improved the accuracy of IDS for detecting the virus by using this method.