Hamzah Mohd. Salleh

Enhancing the efficiency of polymerase chain reaction using graphene nanoflakes

The effect of the recently developed graphene nanoflakes (GNFs) on the polymerase chain reaction (PCR) has been investigated in this paper. The rationale behind the use of GNFs is their unique physical and thermal properties. Experiments show that GNFs can enhance the thermal conductivity of base fluids and results also revealed that GNFs are a potential enhancer of PCR efficiency; moreover, the PCR enhancements are strongly dependent on GNF concentration. It was found that GNFs yield DNA product equivalent to positive control with up to 65% reduction in the PCR cycles. It was also observed that the PCR yield is dependent on the GNF size, wherein the surface area increases and augments thermal conductivity. Computational fluid dynamics (CFD) simulations were performed to analyze the heat transfer through the PCR tube model in the presence and absence of GNFs. The results suggest that the superior thermal conductivity effect of GNFs may be the main cause of the PCR enhancement.

Escherichia coli glucuronylsynthase: an engineered enzyme for the synthesis of β-glucuronides

The glycosynthase derived from E. coli beta-glucuronidase catalyzes the glucuronylation of a range of primary, secondary, and aryl alcohols with moderate to excellent yields. The procedure provides an efficient, stereoselective, and scalable single-step synthesis of beta-glucuronides under mild conditions.

Recombinant bromelain production in Escherichia coli: process optimization in shake flask culture by response surface methodology.

Bromelain, a cysteine protease with various therapeutic and industrial applications, was expressed in Escherichia coli, BL21-AI clone, under different cultivation conditions (post-induction temperature, L-arabinose concentration and post-induction period). The optimized conditions by response surface methodology using face centered central composite design were 0.2% (w/v) L-arabinose, 8 hr and 25°C. The analysis of variance coupled with larger value of R2 (0.989) showed that the quadratic model used for the prediction was highly significant (p < 0.05). Under the optimized conditions, the model produced bromelain activity of 9.2 U/mg while validation experiments gave bromelain activity of 9.6 ± 0.02 U/mg at 0.15% (w/v) L-arabinose, 8 hr and 27°C. This study had innovatively developed cultivation conditions for better production of recombinant bromelain in shake flask culture.

Isolation of fucoxanthin and fatty acids analysis of Padina australis and cytotoxic effect of fucoxanthin on human lung cancer (H1299) cell lines

Fucoxanthin has been successfully isolated from species of Malaysian brown seaweed, namely Padina australis . The purity of the fucoxanthin is >98% as indicated by high performance liquid chromatography analysis. This seaweed also contains a considerable amount of unsaturated fatty acids. Thirteen fatty acids were detected with gas chromatography. However, fatty acid methyl ester (FAMEs) of eicosapentanoic acid (C20:5n-3), arachidonic acid (C20:4n-6), linoleic acid (C18:2n-6) and alpha-linolenic acid (C18:3n-3) contents of P. australis were found to be 2.06, 9.50, 6.37, and 2.83%, respectively. For saturated fatty acids, palmitic acid (C16:0) was found to be the major fatty acid with about 23.97%. Furthermore, data obtained from the methyl thiazolyl tetrazolium (MTT) assay indicated that fucoxanthin reduced the viability of H1299 cell lines, showing an IC 50 value of 2.45 mM. Key words : Brown seaweed, Padina australis , fucoxanthin, fatty acid methyl ester, H1299 cell lines, human lung cancer, MTT assay.

ANALYSIS OF FUCOXANTHIN CONTENT AND PURIFICATION OF ALL-TRANS-FUCOXANTHIN FROM Turbinaria turbinata AND Sargassum plagyophyllum BY SiO2 OPEN COLUMN CHROMATOGRAPHY AND REVERSED PHASE-HPLC

Reversed phase-high performance liquid chromatography (RP-HPLC) was used to analyze fucoxanthin content of two species of Malaysian brown seaweeds, Turbinaria turbinate, and Sargassum plagyophyllum. The fucoxanthin contents of T. turbinata and S. plagyophyllum were 0.59 ± 0.08 and 0.71 ± 0.01 mg/g dry-weight, respectively. Ultraviolet spectrum of fucoxanthin showed the maximum absorbance at 450 nm. Furthermore, the HPLC chromatograms of purified all-trans-fucoxanthin from showed one major peak with a retention time of 7.8 min.

Aquilaria spp. (agarwood) as source of health beneficial compounds: A review of traditional use, phytochemistry and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE Aquilaria spp. (agarwood) has been a part of Ayurvedic and Traditional Chinese Medicine for centuries. Agarwood has also been used as a traditional medicine in Southeast Asian countries, Bangladesh and Tibet. Its common uses include the treatment of joint pain, inflammatory-related ailments, and diarrhoea, as well as a stimulant, sedative and cardioprotective agent. In this paper, we aim to provide an overview of the phytochemistry, ethnomedicinal use, pharmacological activities and safety of plant materials from Aquilaria spp. as an evidence base to further appraise its potential use as a source of health beneficial compounds. MATERIALS AND METHODS Literature abstracts and full text articles from journals, books, reports and electronic searches (Google Scholar, Elsevier, PubMed, Read Cube, Scopus, Springer, and Web of Science), as well as from other relevant websites, are surveyed, analysed and included in this review. RESULTS A literature survey of agarwood plant materials showed that they contain sesquiterpenes, 2(-2-phenylethyl)-4H-chromen-4-one derivatives, genkwanins, mangiferins, iriflophenones, cucurbitacins, terpenoids and phenolic acids. The crude extracts and some of the isolated compounds exhibit anti-allergic, anti-inflammatory, anti-diabetic, anti-cancer, anti-oxidant, anti-ischemic, anti-microbial, hepatoprotective, laxative, and mosquitocidal properties and effects on the central nervous system. Agarwood plant materials are considered to be safe based on the doses tested. However, the toxicity and safety of the materials, including the smoke from agarwood incense burning, should be further investigated. Future research should be directed towards the bio-guided isolation of bioactive compounds with proper chemical characterisation and investigations of the underlying mechanisms towards drug discovery. CONCLUSIONS The traditional medicinal use of agarwood plant materials has provided clues to their pharmacological properties. Indeed, agarwood contains a plethora of bioactive compounds that now elegantly support their use in traditional medicine. As wild agarwood trees are critically endangered and vulnerable, sustainable agricultural and forestry practices are necessary for the further development and utilization of agarwood as a source of health beneficial compounds.

Localization of the antigenic sites of newcastle disease virus nucleocapsid using a panel of monoclonal antibodies.

A panel of six monoclonal antibodies (mAbs) against the nucleocapsid (NP) protein of Newcastle disease virus (NDV) was produced by immunization of Balb/c mice with purified recombinant NP protein. Western Blot analysis showed that all the mAbs recognized linearized NP epitopes. Three different NP antigenic sites were identified using deleted truncated NP mutants purified from Escherichia coli. One of the antigenic sites was located at the C-terminal end (residues 441 to 489) of the NP protein. Two other antigenic sites were located within the N-terminal end (residues 26-121 and 122-375). This study demonstrates that the N- and C-terminal ends of the NP proteins are responsible in eliciting immune response, thus it is most likely that these ends are exposed on the NP.

Effects of Pretreatment on Properties of Gelatin from Perch (Lates Niloticus) Skin

Fish gelatins obtained from perch fish skin pretreated with various solutions containing acetic acid, sodium hydroxide (NaOH) and sodium chloride (NaCl) were successfully characterized for their nanostructure pattern using field emission scanning electron microscopy. Each pretreatment transformed collagen to gelatin with fibril, zigzag cracks, straight rods, and cross-linked rods nanostructure patterns. Pretreatment solutions also affect the gel yield, gel strength, amino acid profile, and functional groups in perch gelatin as analyzed by Fourier transform infrared spectroscopy. Samples pretreated with NaCl, NaOH, and acetic acid solution showed the highest gel yield (22.84%) and gel strength (179.84 g). Fourier transform infrared spectra for perch gelatins also revealed weak C–N amide II and III bond stretches as well as weak C=O bond stretch.

Developing CAS models in immunology teaching

How can mathematical modelling be integrated with complex network of biological system in comprehensive education? There are mutual agreements between academia from various fields that mathematical modelling is an important part of the curriculum. Immunology is a complex subject and for student to fully understand its complex interaction at molecular level requires computer supported models. This research tries to resolve the ever emerging problem of teaching immunology in higher education. The main objective is to develop multimedia educational software to enhance immunology teaching, with the use of a Computer Algebra System (CAS) that fully utilizes mathematical equation, modelling and simulation of complex network of gene regulation and metabolism. A survey was conducted among students in higher learning institutions, and the result clearly shows that the current teaching method is not feasible to the current learning style. To overcome this, new teaching techniques to support the required understanding need to be introduced. With the development of this educational package that uses new modelling and simulation techniques hopefully can aid in teaching some of immunology courses.

Fabrication of Fucoxanthin-Loaded Microsphere(F-LM) By Two Steps Double-Emulsion Solvent Evaporation Method and Characterization of Fucoxanthin before and after Microencapsulation

Microencapsulation is a promising approach in drug delivery to protect the drug from degradation and allow controlled release of the drug in the body. Fucoxanthin-loaded microsphere (F-LM) was fabricated by two step w/o/w double emulsion solvent evaporation method with poly (L-lactic-coglycolic acid) (PLGA) as carrier. The effect of four types of surfactants (PVA, Tween-20, Span-20 and SDS), homogenization speed, and concentration of PLGA polymer and surfactant (PVA), respectively, on particle size and morphology of F-LM were investigated. Among the surfactants tested, PVA showed the best results with smallest particle size (9.18 µm) and a smooth spherical surface. Increasing the homogenization speed resulted in a smaller mean F-LM particle size [d(0.50)] from 17.12 to 9.18 µm. Best particle size results and good morphology were attained at homogenization speed of 20 500 rpm. Meanwhile, increased PLGA concentration from 1.5 to 11.0 (% w/v) resulted in increased F-LM particle size. The mean particle size [d(0.5)] of F-LM increased from 3.93 to 11.88 µm. At 6.0 (% w/v) PLGA, F-LM showed the best structure and external morphology. Finally, increasing PVA concentration from 0.5 to 3.5 (% w/v) resulted in decreased particle size from 9.18 to 4.86 µm. Fucoxanthin characterization before and after microencapsulation was carried out to assess the success of the microencapsulation procedure. Thermo gravimetry analysis (TGA), glass transition (Tg) temperature of F-LM and fucoxanthin measured using DSC, ATR-FTIR and XRD indicated that fucoxanthin was successfully encapsulated into the PLGA matrix, while maintaining the structural and chemical integrity of fucoxanthin.