Masalah Pelajar dalam Menamakan Sebatian-Sebatian Organik Berpolifungsi

An investigation of students' unsuccessful attempts in naming poly functional organic compounds using the IUPAC nomenclature is described, The effectiveness of the teaching strategies used to help students develop skill and confidence in using the systematic nomenclature is also discussed

A Systematic Approach to Solving Problems in Structure Analysis

An investigation of students' unsuccessful attempts to solve problems in structure analysis, even though they possessed all the prerequisite knowledge, is described. The proposed teaching strategies given to these students to help them develop confidence and skills in problem-solving and the evaluation of these strategies are discussed

Biosynthesis of Diverse Class Flavonoids <em>via</em> Shikimate and Phenylpropanoid Pathway

Flavonoids are natural products, which are useful in the protection of various types of human diseases. Several bioactive flavonoids as chalcones, flavonols, flavanol, flavones, flavanone, flavan, isoflavonoids, and proanthocyanidin, are found in parts as leaves, root, bark, stem, flowers, weed, fruits of plant species. Flavonoids are synthesized in higher plant species via the shikimate pathway, phenylpropanoid and polyketide pathway. The chalcones and flavanones are central intermediates of the pathway, which give several diverse classes of flavonoids. Central intermediates pathway (chalcones and flavanones pathway) depends on plants species and group of enzymes such as hydroxylases, reductases and isomerases to give different classes of flavonoids skeleton. The anthocyanins, isoflavonoids and condensed tannin (proanthocyanidins) are an important class of flavonoids, which synthesized by flavanones. Mostly, biosynthesis of flavonoids start from phenylpropanoid pathway. The phenylpropanoid pathway starts from shikimate pathway. The shikimate pathway starts from phosphoenol pyruvate and erythrose 4-phosphate

16S rRNA Barcoding technique for species identification of processed sea cucumbers from selected Malaysian markets

In food industry, wide-ranging processing of sea cucumbers (Phylum Echinodermata: Class Holothuroidea) including gutting, boiling, roasting, and subsequent preservation procedures are frequently needed prior to marketing. These processes cause body deformation of the sea cucumbers, thus leading to difficulties in species identification and confirmation of the processed sea cucumbers or beche-de-mer. Furthermore, beche-de-mer products in Malaysian markets are often unlabelled or mislabelled. Economic fraud, health hazards, and illegal trade of protected species are the potential major consequences of the issues. Therefore, a reliable, reproducible, and rapid technique for species identification is required. For that reason, this study was conducted to determine species identity of 25 beche-de-mer specimens that were not tagged with species details from four selected Malaysian markets. Five reference samples were also included in the analyses consisting of fresh samples that were morphologically identified as Stichopus horrens and Holothuria (Mertensiothuria) leucospilota from Pangkor Island, Perak, Malaysia. Phylogenetic analyses of 30 partial sequences of non-protein-coding 16S mitochondrial ribosomal RNA (rRNA) gene using five main methods i.e. Neighbour-Joining (NJ), Maximum Likelihood (ML), Minimum Evolution (ME), Unweighted Pair Group Method with Arithmetic Mean (UPGMA), and Maximum Parsimony (MP) showed the presence of two main clusters of the beche-demer specimens: Stichopodidae (gamat family) and Holothuriidae (timun laut family). The beche-de-mer specimens of S. horrens, Stichopus herrmanni, and Thelenota anax were the three gamat species that clustered under the family Stichopodidae. Meanwhile, the beche-de-mer specimens of H. leucospilota, Holothuria (Halodeima) edulis, Holothuria (Metriatyla) scabra, and H. scabra var. versicolor were the four timun laut species that clustered under the family Holothuriidae. In fact, the outcomes of this study suggested the potential of 16S mitochondrial rRNA gene sequencing technique to be used by the enforcement agencies in monitoring and overcoming the issues of species substitution and product mislabeling of beche-de-mer products in Malaysian markets

16S rRNA barcoding technique for species identification of processed sea cucumbers from selected Malaysian markets

In food industry, wide-ranging processing of sea cucumbers (Phylum Echinodermata: Class Holothuroidea) including gutting, boiling, roasting, and subsequent preservation procedures are frequently needed prior to marketing. These processes cause body deformation of the sea cucumbers, thus leading to difficulties in species identification and confirmation of the processed sea cucumbers or beche-de-mer. Furthermore, beche-de-mer products in Malaysian markets are often unlabelled or mislabelled. Economic fraud, health hazards, and illegal trade of protected species are the potential major consequences of the issues. Therefore, a reliable, reproducible, and rapid technique for species identification is required. For that reason, this study was conducted to determine species identity of 25 beche-de-mer specimens that were not tagged with species details from four selected Malaysian markets. Five reference samples were also included in the analyses consisting of fresh samples that were morphologically identified as Stichopus horrens and Holothuria (Mertensiothuria) leucospilota from Pangkor Island, Perak, Malaysia. Phylogenetic analyses of 30 partial sequences of non-protein-coding 16S mitochondrial ribosomal RNA (rRNA) gene using five main methods i.e. Neighbour-Joining (NJ), Maximum Likelihood (ML), Minimum Evolution (ME), Unweighted Pair Group Method with Arithmetic Mean (UPGMA), and Maximum Parsimony (MP) showed the presence of two main clusters of the beche-demer specimens: Stichopodidae (gamat family) and Holothuriidae (timun laut family). The beche-de-mer specimens of S. horrens, Stichopus herrmanni, and Thelenota anax were the three gamat species that clustered under the family Stichopodidae. Meanwhile, the beche-de-mer specimens of H. leucospilota, Holothuria (Halodeima) edulis, Holothuria (Metriatyla) scabra, and H. scabra var. versicolor were the four timun laut species that clustered under the family Holothuriidae. In fact, the outcomes of this study suggested the potential of 16S mitochondrial rRNA gene sequencing technique to be used by the enforcement agencies in monitoring and overcoming the issues of species substitution and product mislabeling of beche-de-mer products in Malaysian markets

Employing Information Theoretic Measures and Mutagenesis to Identify Residues Critical for Drug-Proton Antiport Function in Mdr1p of Candida albicans

By employing information theoretic measures, this study presents a structure and functional analysis of a multidrug-proton antiporter Mdr1p of Candida albicans. Since CaMdr1p belongs to drug-proton antiporter (DHA1) family of Major Facilitator Superfamily (MFS) of transporters, we contrasted DHA1 (antiporters) with Sugar Porter family (symporters). Cumulative Relative Entropy (CRE) calculated for these two sets of alignments enabled us to selectively identify conserved residues of not only CaMdr1p but for the entire DHA1 family. Based on CRE, the highest scoring thirty positions were selected and predicted to impart functional specificity to CaMdr1p as well as to other drug-proton antiporters. Nineteen positions wherein the CaMdr1p residue matched with the most frequent amino acid at a particular alignment position of DHA1 members were subjected to site-directed mutagenesis and were replaced with either alanine or leucine. All these mutant variants, except one, displayed either complete or selective sensitivity to the tested drugs. The enhanced susceptibility of these mutant variants was corroborated with the simultaneously abrogated efflux of substrates. Taken together, based on scaled CRE between two MFS sub-families, we could accurately predict the functionally relevant residues of CaMdr1p. An extrapolation of these predictions to the entire DHA1 family members as validated from previously published data shows that these residues are functionally critical in other members of the DHA1 family also

Checklist of Marine Fungi and Yeasts Associated with Holothuria (Mertensiothuria) leucospilota from Pangkor Island

Marine microorganisms such as fungi and yeasts can adapt to extreme marine environment conditions and play different roles especially in the nutrient cycling and as bioindicator of ocean change. This study was carried out to isolate and identify fungi and yeasts associated with Holothuria (Mertensiothuria) leucospilota from Pangkor Island, Perak, Malaysia. Two specimens of H. leucospilota were collected from Giam Island and Teluk Nipah Beach of Pangkor Island. Nine samples of fungi and ten samples of yeasts were isolated from the internal and external parts of the H. leucospilota specimens such as cuticle, tentacle, coelomic fluid, cloaca, cuvierian tubules, and surrounding sediment and seawater. Polymerase Chain Reaction (PCR) and DNA sequencing of the Internal Transcribed Spacer (ITS) region were applied for species identification of the microorganisms. Sequence analyses of the ITS region resulted in the identification of five genera of fungi i.e. Cladosporium, Curvularia, Polyporaceae, Acremonium, and Penicillium; and four genera of yeasts i.e. Sterigmatomyces, Pichia, Debaryomyces, and Candida with some of them could be identified up to the species level. The fungi and yeasts isolated from the H. leucospilota specimens from Pangkor Island could have potential biotechnological applications which can be further characterised

Transesterification of Waste Cooking Oil using Calcium Loaded on Deoiled Spent Bleaching Clay as A Solid Base Catalyst

Waste cooking oil has a high potential as a raw material in biodiesel production due to its abundant availability and cheapest among other feedstock. Hence transesterification reaction is carried out using waste cooking oil in this research. The objective of this study is to synthesize and characterize the catalyst. On the other hand, deoiled spent bleaching clay impregnated with 40% CaO utilized as a catalyst. Optimization was carried out on methanol to oil molar ratio (6:1-24:1), catalyst loading (3-10 wt.%) and reaction duration (2-10 h). The catalyst of deoiled spent bleaching clay doped with 40% CaO was prepared by wet impregnation method and calcined at 500 °C for 4 hours. The catalyst shows high activity under optimum condition of 5 hours of reaction time, 12:1 of methanol to oil molar ratio with 7 wt.% of catalyst. The transesterification yields 84.7% methyl ester. Therefore, this catalyst has potential to be used in the transesterification of waste cooking oil in producing biodiesel due to its high activity

A Study on The Potential Pathways For Existing Drugs Against COVID-19

Coronavirus infectious disease 2019 (COVID-19) is a global pandemic declared by the World Health Organization (WHO) in March 2020. This emerging infectious disease is rapidly transmitted and does not only pose a global threat to public health but also badly affects the economy. At present, there is no effective drug to treat COVID-19, leading to a significant challenge upon current global attempts at restraining the outbreak. There are several currently available drugs, also considered as the repurposed drugs are in use for treatment against COVID-19. However, these drugs are not as efficient as it is hoped. Therefore, this study is conducted to further explore into other established antivirus that could function better for COVID-19 treatment. In addition, the pathways that associated with the drugs are identified and potential targeted proteins for the repurposed drugs are also pointed out. The articles for review were selected from several search engine databases, which are ScienceDirect, SpringerLink, PubMed, and Scopus including the keywords COVID-19, SARS, MERS, potential pathways for antiviral drugs as well as repurposed drugs, with more than 50 primary research articles identified. Findings and analysis have discovered potential repurposed drugs that could be used for COVID-19, namely bisoxatin, nitazoxanide and teicoplanin which could be involved in corona-related pathways. Meanwhile, the associated pathways are JAK-STAT, Neprilysin (NEP) and cGAS-STING that counteract excessive immune response and act as a medium for the drugs to access antiviral activities. The repurposed drugs target protein identification is also a critical significance and it was found that S-protein, TMPRSS2, RdRp and RDB which are the signalling protein can be interrupted by the repurposed drugs, presenting a promising antivirus against SARS-CoV-2.&nbsp; It is concluded that this study will provide information to assist logical design of the repurposed drug for its effectiveness as antivirus against COVID-19