Investigating the anti-proliferative and pro-apoptotic effects of 6-gingerol and 6-shogaol extracted from Zingiber officinale

Existing treatments for cancer often antagonise the host by exhibiting cytotoxic effects on somatic cells, causing poor patient prognosis. This study aims to investigate the anti-proliferative and cytotoxic effects of 6-shogaol [(E)-1-(4-Hydroxy-3- methoxyphenyl)dec-4-en-3-one] derived from Zingiber officinale (ginger) rhizomes, to determine its viability as an anti-cancer agent. Crude Ginger Extract (CGE) was obtained from ginger rhizomes via water-solvent-based reflux. 6-shogaol content was then estimated via the Folin-Ciocalteau Assay. CGE’s anti-proliferative capacity was determined by quantifying the rate of Allium cepa root elongation, and mitotic-index of Allium cepa root tip cells, exposed to varying concentrations [0, 24, 48, 72, 96, 120 mg/L Gallic Acid Equivalent] of CGE. Root apical meristematic cells were as a proximate model of cancer cell proliferation. The cytotoxicity of CGE was quantified via the Tryphan Blue Cell Viability assay, using log-phase cultures of baker’s yeast (Saccharomyces cerevisiae) to model normal somatic cells of the host body. A significant negative correlation was observed between CGE concentration and the rate of root elongation (p<0.001), and between CGE concentration and the mitotic index of Allium cepa root apical meristematic cells (p<0.001), suggesting that CGE exhibits anti-proliferative activity in a concentration-dependent manner. No significant change (p=0.748) was observed between S. cerevisiae cell viability and CGE concentration for concentrations up to 120mg/L GAE of CGE, suggesting that CGE exhibits an anti-proliferative effect independent of cellular cytotoxicity. In conclusion, CGE could potentially exhibit significant anti-cancer activity whilst sparing normal somatic cells, thus being a viable, economical and effective anti-cancer agent.

Silver nanoparticles have seen usage in the form of catalysts and micro-electronics. Due to this, silver nanoparticles are extremely useful in the field of medicine. The usual chemical method for synthesizing such nanoparticles involves the use of toxic chemicals which are expensive and are potential threat to the environment and public health. Hence this study aims to synthesize silver nanoparticles using green methods via the use of lalang extract. The silver nanoparticles synthesized were characterized by UV-VIS spectrophotometry and their sizes determined by Scanning Electron Microscopy (SEM). The anti-bacterial properties against Staphylococcus epidermidis and Escherichia coli and anti-fungal properties against Aspergillus niger of the silver nanoparticles synthesized were also studied. Lalang which is unexploited in Singapore can be put to good use by using it as a starting material for the synthesis of silver and nanoparticles.

M Venkatashamy Reddy, Department of Chemistry, National University of Singapore

Nanostructured CoN,CoO and Co3O4 as a high capacity and long life anodes for Li-ion batteries

This project investigates bulk methods of preparing Co₃O₄, CoO and CoN in the form of nano-rods/ nano-particles and studies their electrochemical properties and evaluates their use anode materials for Li-ion batteries. These materials have about 2.5 times the theoretical capacity of commercial graphite (372 mAhg^-1), making them excellent choices for anodes. We proposed simple methods to prepare these materials in bulk to test the viability of real-life usage of these batteries. CoO allows for Li₂O and Co metal to form during discharging, allowing for a high theoretical capacity of 715 mAhg^-1. Co₃O₄ allows for 4 Li₂O and 3Co to form, and has a theoretical capacity of 890 mAhg^-1. CoN is theoretically the best of the three because the nitrogen allows for Li₃N and Co to form, resulting in theoretical capacity of 1100 mAhg^-1. Scanning Electron Microscopes (SEM), X-Ray Diffraction (XRD), the Brunauer-Emmett-Teller (BET) surface and density methods, and gas pycnometry were used to characterise the materials. Cyclic voltammetry (CV) and galvanostatic cycling experiments were conducted to analyse redox potentials and structural phase transformations respectively. Electrochemical impedance spectroscopy (EIS) was performed to analyse electrode kinetics and other characteristics. The reversible capacity of these compounds is of the order CoO, CoN, Co₃O₄. Two Co₃O₄ cells were tested at different current rates for 60-70 cycles. CoO and CoN batteries were tested for 59 cycles each. Co₃O₄ showed almost no capacity fading. CoO and CoN even showed increasing capacities, with CoO far exceeding theoretical capacity because more active material participated in the electrochemical cycling.

A/P Vladimir Korzh, Institute of Molecular and Cell Biology, A*STAR

Analysis of Mutants Affecting NFkB Signaling in Developing Zebrafish

Cellular & Molecular Biology

The NF-kB signaling pathway is involved in many biological activities, including, but not limited to, resistance against infection and development of lymphoid system. This signaling is regulated by a key protein Ikk2, which previously based on transient loss-of-function experiments, has been implicated in formation of the body axis and in particular the notochord, an important embryonic structure that sets in motion a complex process of whole body morphogenesis. To address the role of Ikk2 in greater detail, mutations were generated at two sites in the ikk2 gene and two sets of mutants (termed +2 and Δ 7 mutants) were studied. In this study, in situ hybridization with gene markers revealed that +2 maternal zygotic mutants exhibited aberrant morphogenesis in terms of impaired dorsal identity formation, atypical yolk syncytial layer formation and defects in primitive haematopoiesis. Furthermore, Δ7 zygotic mutants displayed microbleeds in the trunk, brain and eyes. Taken together, results suggest a strong role of Ikk2 in gastrulation and in maintaining vessel integrity. 

Raffles Girls’ School (Secondary)

Dr. Gautam Sethi, Department of Pharmacology, NUS Yong Loo Lin School of Medicine

Project to explore the potential anti-proliferative/pro-apoptotic effects of mangosteen peel extract and alpha-mangostin in triple negative breast cancer cell lines

Cellular & Molecular Biology

Triple-negative breast cancer (TNBC) lacks hormone and Her2 receptors and thus is unresponsive to hormone therapy. Despite chemotherapy, TNBC has poor prognosis due to its propensity for recurrence and metastasis. STAT3 is a major promoter of breast cancer growth and progression, and thus has become a widely explored target for new drug development. α-Mangostin was shortlisted due to strong bioactivity measured preliminarily in crude mangosteen peel extract. Therefore, this study investigates α-mangostin’s ability to inhibit the tyrosine phosphorylation of STAT3 and the transcriptional regulation of STAT3-specific target genes: cyclin D1 (proliferative), Bcl-2, survivin (survival) and VEGF (angiogenic). The study also determines its antiproliferative and pro-apoptotic properties. By conducting Western blotting, we found that α-mangostin suppressed STAT3 phosphorylation and expression of STAT3, as well as down-regulated STAT3-specific target genes. Strong antiproliferative activity (<20μg/ml for 24h and 48h in MDA-MB-231 and BT-549) measured by the MTT assay could be attributed to the down-regulation of COX-2 and cyclin D1 genes. Time-dependent cleavage of PARP and results from the DNA fragmentation ELISA also proposes that α-mangostin induces apoptosis on MDA-MB-231 cells in a time-dependent manner. Down-modulation of caspase-3 suggests that the apoptosis observed was caspase-3 dependent. Overall, this study suggests that α-mangostin mediates its strong in vitro anti-proliferative and pro-apoptotic properties on TNBC through suppression of the STAT3 pathway, STAT3-regulated genes and COX-2 gene. These results are significant in terms of developing a natural complement to chemotherapeutic drugs so as to provide the best and most sustainable improvement to management of TNBCs.

Kambiz Ansari Mahabadi, Institute of Materials Research and Engineering, A*STAR

"The microfiltration industry has growing over the past years. Many researchers have been thoroughly researching microfiltration membrane technology for various applications in the field of biotechnology and water purification industry. Similarly, we too are interested in this new technology and we aim to be able to contribute to this growing industry through our work. This work aims to produce functional nickel membranes with nanopores via the formation of electrolytic hydrogen bubbles during nickel electroplating and using technologies of UV lithography and nickel electroplating to regulate the positioning and frequency of pores formed by altering the substrate morphology that is to be electroplated. Using UV lithography processes, we fabricated substrates with micro-sized bubble-trapping structures that can be used to regulate the formation of pitting due to hydrogen evolution and fabricate an array of uniformly sized through holes in the thin film of nickel to produce strong free-standing nickel filter membranes. Through analysis of the substrate via optical microscopy and SEM imaging, many of the pits formed were found to form on top or in the immediate area surrounding the pillars. We also managed to characterise the pore design created through the hydrogen pitting phenomena as a grooved and conically shaped pore with a ~2.0 microns hole at the tip of the pore. Triangular pits were also seen to be formed, which if replicated, could produce clustered, centralised triangular pores in the membrane. This work can hopefully add knowledge and ideas to the current microfiltration industry and further research in this sector.

NUS High School of Mathematics and Science

Dr Sun Ting, Department of Materials Science and Engineering, Nanyang Technological University

Investigation of Sn Gradient-doped Bi2Te3 Thin Films using Sputter Deposition

Engineering: Materials and Bioengineering

A new class of thermoelectric thin films [1-5] using gradient doping has been introduced and investigated. Films were fabricated using Direct Current (DC) Magnetron Sputtering [13] with Tin (Sn) strips, of low thickness, physically attached to a Bi2Te2.7Se0.3 target. This novel method is quicker and more economical then using several targets of different compositions [15]. Firstly, there was an approximately linear increase in Sn content; x ≈ 0, x ≈ 0.25, x ≈ 0.58 and x ≈ 0.73 with the addition of zero, one, two and three Sn strips to fabricate each of the Bi2-xSnxTe2.7Se0.3 films respectively. From resistivity (ρ) and Seebeck Coefficient (α) measurements obtained by ZEM-3, x ≈ 0.58 proved to be best amongst the four films. Next, gradient doped films were successfully fabricated with four layers of increasing Sn dopant concentration (zero to three Sn strips). The gradient doped film yielded significantly lower resistivities than conventional undoped and Sn-doped Bi2Te2.7Se0.3 films and comparable Seebeck Coefficients. Thus, the overall Power Factor (α2ρ-1) values were enhanced by nearly one order in our gradient Sn-doped films ( , revealing the immense potential of gradient doping in thin films to harvest more electrical energy from waste heat for green technology application.

National Junior College

Nikolai Yakovlev, Institute of Materials Research and Engineering. A*STAR

Real-time Optical Monitoring of Heterogeneous Reactions

The conventional method to measure rate of reactions is done by extracting samples at various period of time, send for analysis and determine the amount of product and initial compound present at each point of time. However, such method is troublesome, complicated and is unable to detect the rate as the reaction proceeds. Real-time monitoring of reactions is usually expensive and requires complicated equipment. We decided to go another way, to immobilize one of the molecules on the surface of the substrate and monitor the reaction with another molecule using precision ellipsometry. Precision ellipsometry is a highly accurate optical technology that is able to detect the change in thickness of an ultra-thin film at the molecular level. With a polarization modulator, the system can measure the rotation of polarization vector with a precision of 10 microradians, which translates to 0.01 nm. With a carefully constructed prism-shaped cuvette, the precision ellipsometry is adopted for liquids for the first time. Bonding of amino silane on silicon oxide substrate and polystyrene sulfonate on amino silane was recorded in real time. In fact, the results obtained are in agreement with the concept that the rate of reaction decreases with lower concentration. This proves the concept of applicability of precision ellipsometry system to measure reaction kinetics.

National Junior College

Craig McFarlane, Singapore Institute of Clinical Sciences, National University of Singapore

Role of miRNAs in the Development of Insulin Resistance in Humans

Cellular & Molecular Biology

Type II diabetes mellitus is a chronic and increasingly widespread disease. The recent discovery of microRNAs has offered new insight to the disease. miRNAs are short oligonucleotide sequences that act as post transcriptional regulators, inhibiting the production of their target gene product. Published reports have shown that these miRNAs play a role in cancer, cardiovascular diseases and type II diabetes. However, not much is known about the role miRNAs play in insulin resistance, a precursor to type II diabetes. Through miRNA microarray analysis, 20 miRNAs were found to be differentially expressed in the insulin resistant human myoblast model, suggesting that they might play a role in the pathogenesis of diabetes. In this project, we aim to investigate whether miRNAs have a role in causing insulin resistance in skeletal muscle and how they might influence the development of type II diabetes. Real time quantitative PCR was used to verify the microarray results. The most significantly overexpressed miRNAs (miR-380-3p and miR-145-5p) were used for in silico analysis to find their putative target genes. In particular, those genes that have key roles in either the insulin signaling pathway or the glucose metabolic pathway were focused upon. Through overexpression of miR-145-5p and miR-380-3p in myoblasts, reduction in the expression of some of these predicted targets was found, suggesting that they are regulated by the miRNAs of interest which may contribute to the onset of type II diabetes.

Effect of ultraviolet b light intensity on the synthesis of alleochemicals in Typha latifolia, which inhibit the growth of Chlorella vulgaris

"Pristine clear lakes are truly now a thing of the past. Due to enhanced eutrophication, many water bodies in developing countries are undergoing algal bloom. This has knock on effects on food chains and a reduction in biodiversity. Meanwhile, depletion of the ozone in the stratosphere causes higher intensities of incident ultraviolet b radiation. Literature has shown that current physical and chemical methods used to control eutrophication are inefficient and that there are no ramifications from algal inhibition by allelopathy and that the allelochemical in Typha latifolia, cholesteryl cis-9-octadecenoate, inhibits the growth of Chlorella vulgaris. The aim of this essay is to investigate the effect of UVB intensity in the synthesis of allelochemicals in Typha latifolia, which inhibit the growth of Chlorella vulgaris. Cattails were exposed to UVB intensities (20, 40, 60, 80 and 100 W) for 10 hours. Total phenolic and flavonoid content of the ethyl acetate extracts of the leaves were estimated every 2 hours using folin ciocalteu and the aluminium chloride colorimetry. The results show a direct correlation between UVB intensity and total phenols and flavonoids. The effect of the various extracts on Chlorella vulgaris was investigated by manual enumeration (hematocytometer), measurement of the pH of medium, quantification of total chlorophyll content, measurement of carbon dioxide gas uptake through hydrogencarbonate indicator, measuring diameter of zone of inhibition through agar plate diffusion and calculating the rate of 2,6-dichlorophenolindophenol (DCPIP) reduction through the exposure of the isolated chloroplasts of Chlorella vulgaris to the various extracts and DCPIP. The results show that as the UVB intensity increases, the anti-proliferative ability of Broadleaf Cattails on Chlorella vulgaris increases.

Sandeep Kumar Tiwari, Department of Materials Science and Engineering, Nanyang Technological University

Materials and Bioengineering

Superhydrophobic surfaces are of high scientific and technological interest because of their implications for areas ranging from biomedical device, fuel transport and architecture to sportswear. Bioinspirations from non-wetting surfaces such as lotus leaves have led to the development of liquid-repellent textured surfaces. However, little attention is given to their air-retaining properties underwater to achieve extreme non-wettability. Therefore, this project is aimed to create a robust synthetic surface for textile used in sportswear that not only keep athletes dry under water but also improve their performance due to drag reduction under water.