MyMedR

Displaying publications 41 - 60 of 161 in total

Abstract:

Sort:

Fulltext Antecedents of the Attitudes Toward Singlehood Among Young Adults in Malaysia, Japan, and India

Tan CS, Cheng SM, Nakayama T, George S

Front Psychol, 2021;12:756090.
PMID: 34867655 DOI: 10.3389/fpsyg.2021.756090

With both theories and empirical studies supporting the benefits of having a romantic relationship, there remains an increasing tendency of staying single being documented globally. It is thus important to understand the antecedent factors of such voluntary single movement. Guided by the Investment Model of Commitment (IMC) process, the roles of subjective socioeconomic status (SSES), relational mobility, and desirability of control in attitudes toward singlehood were investigated. A total of 1,108 undergraduate students from Malaysia (n=444), Japan (n=316), and India (n=348) answered an online survey consisting of the Attitudes toward Singlehood Scale, MacArthur Scale of SSES, Relational Mobility Scale, Desirability of Control Scale, Mini-Social Phobia Inventory, and Single Item Narcissism Scale. Hierarchical multiple regression analysis showed a persistent positive relationship between desirability of control, but not socioeconomic status and relational mobility, with attitudes toward singlehood, even after statistically excluding the effects of social anxiety and narcissism. A similar pattern was also observed among those who were currently single. Moreover, an interaction effect of socioeconomic status and relational mobility was found in further exploratory analysis. The results highlight that retaining the autonomy and flexibility of managing one's own life and financial concern are the key reasons young adults prefer staying single to engaging in a romantic relationship. Implications and recommendations for future research are also presented in this study.
A nationwide survey on the knowledge and attitudes of Malaysian optometry students on patients' visual experiences during cataract surgery

Tan CS, Chen AH, Au Eong KG

Ann Acad Med Singap, 2006 Feb;35(2):72-6.
PMID: 16565757

INTRODUCTION: During cataract surgery under regional (retrobulbar, peribulbar or sub- Tenon's) or topical anaesthesia, many patients experience a variety of visual sensations in their operated eye intraoperatively. Between 3% and 16.2% of patients are frightened by their intraoperative visual experiences, which may increase the risk of intraoperative complications and affect patients' satisfaction with the surgery. This study aims to determine optometry students' beliefs and knowledge of visual sensations experienced by patients during cataract surgery under regional and topical anaesthesia.
MATERIALS AND METHODS: A nationwide survey of all Malaysian optometry students using a standardised, self-administered questionnaire.
RESULTS: All 129 optometry students participated in the survey, giving a 100% response rate. Overall, 26.4% and 29.5% of the students believed that patients undergoing cataract surgery under regional and topical anaesthesia, respectively, may experience no light perception, while 78.3% and 72.9%, respectively, thought that patients would experience light perception. Many respondents also believed that patients might experience a variety of other visual sensations. Of all respondents, 70.5% and 74.4% of students believed that patients undergoing cataract surgery under regional and topical anaesthesia, respectively, may be frightened by their visual experience and 93.0% and 85.3%, respectively, felt that preoperative counselling might help to alleviate this fear.
CONCLUSION: Many optometry students are aware that patients might encounter a variety of visual sensations during cataract surgery under local anaesthesia. A high proportion of students believe that patients may experience fear as a result of the intraoperative visual sensations and felt that preoperative counselling would be helpful.
Fulltext Transcriptome Analysis Revealed Highly Expressed Genes Encoding Secondary Metabolite Pathways and Small Cysteine-Rich Proteins in the Sclerotium of Lignosus rhinocerotis

Yap HY, Chooi YH, Fung SY, Ng ST, Tan CS, Tan NH

PLoS One, 2015;10(11):e0143549.
PMID: 26606395 DOI: 10.1371/journal.pone.0143549

Lignosus rhinocerotis (Cooke) Ryvarden (tiger milk mushroom) has long been known for its nutritional and medicinal benefits among the local communities in Southeast Asia. However, the molecular and genetic basis of its medicinal and nutraceutical properties at transcriptional level have not been investigated. In this study, the transcriptome of L. rhinocerotis sclerotium, the part with medicinal value, was analyzed using high-throughput Illumina HiSeqTM platform with good sequencing quality and alignment results. A total of 3,673, 117, and 59,649 events of alternative splicing, novel transcripts, and SNP variation were found to enrich its current genome database. A large number of transcripts were expressed and involved in the processing of gene information and carbohydrate metabolism. A few highly expressed genes encoding the cysteine-rich cerato-platanin, hydrophobins, and sugar-binding lectins were identified and their possible roles in L. rhinocerotis were discussed. Genes encoding enzymes involved in the biosynthesis of glucans, six gene clusters encoding four terpene synthases and one each of non-ribosomal peptide synthetase and polyketide synthase, and 109 transcribed cytochrome P450 sequences were also identified in the transcriptome. The data from this study forms a valuable foundation for future research in the exploitation of this mushroom in pharmacological and industrial applications.
Nutritional composition, antioxidant properties, and toxicology evaluation of the sclerotium of Tiger Milk Mushroom Lignosus tigris cultivar E

Kong BH, Tan NH, Fung SY, Pailoor J, Tan CS, Ng ST

Nutr Res, 2016 Feb;36(2):174-83.
PMID: 26598045 DOI: 10.1016/j.nutres.2015.10.004

The Tiger Milk Mushroom (Lignosus spp.) is an important medicinal mushroom in Southeast Asia and has been consumed frequently by the natives as a cure for a variety of illnesses. In this study, we hypothesized that Lignosus tigris (cultivar E) sclerotium may contain high nutritional value and antioxidant properties, is nontoxic and a potential candidate as a dietary supplement. The chemical and amino acid compositions of the sclerotium were evaluated and antioxidant activities of the sclerotial extracts were assessed using ferric reducing antioxidant power; 1,1-diphenyl-2-picrylhydrazyl; and superoxide anion radical scavenging assays. Acute toxicity of the L. tigris E sclerotium was assessed using a rat model study. The sclerotium was found to be rich in carbohydrate, protein, and dietary fibers with small amounts of fat, calories, and sugar. The amino acid composition of the protein contains all essential amino acids, with a protein score of 47. The sclerotial extracts contain phenolics, terpenoids, and glucan. The ferric reducing antioxidant power values of the various sclerotial extracts (hot water, cold water, and methanol) ranged from 0.008 to 0.015 mmol min(-1) g(-1) extract, while the 1,1-diphenyl-2-picrylhydrazyl and superoxide anion radical scavenging activities ranged from 0.11 to 0.13, and -2.81 to 9.613 mmol Trolox equivalents g(-1) extract, respectively. Acute toxicity assessment indicated that L. tigris E sclerotial powder was not toxic at the dose of 2000 mg kg(-1). In conclusion, L. tigris E sclerotium has the potential to be developed into a functional food and nutraceutical.
Fulltext Genome-based proteomic analysis of Lignosus rhinocerotis (Cooke) Ryvarden sclerotium

Yap HY, Fung SY, Ng ST, Tan CS, Tan NH

Int J Med Sci, 2015;12(1):23-31.
PMID: 25552915 DOI: 10.7150/ijms.10019

Lignosus rhinocerotis (Cooke) Ryvarden (Polyporales, Basidiomycota), also known as the tiger milk mushroom, has received much interest in recent years owing to its wide-range ethnobotanical uses and the recent success in its domestication. The sclerotium is the part with medicinal value. Using two-dimensional gel electrophoresis coupled with mass spectrometry analysis, a total of 16 non-redundant, major proteins were identified with high confidence level in L. rhinocerotis sclerotium based on its genome as custom mapping database. Some of these proteins, such as the putative lectins, immunomodulatory proteins, superoxide dismutase, and aegerolysin may have pharmaceutical potential; while others are involved in nutrient mobilization and the protective antioxidant mechanism in the sclerotium. The findings from this study provide a molecular basis for future research on potential pharmacologically active proteins of L. rhinocerotis.
Fulltext Anti-inflammatory effect of the sclerotium of Lignosus rhinocerotis (Cooke) Ryvarden, the Tiger Milk mushroom

Lee SS, Tan NH, Fung SY, Sim SM, Tan CS, Ng ST

BMC Complement Altern Med, 2014;14:359.
PMID: 25256382 DOI: 10.1186/1472-6882-14-359

The sclerotium of Lignosus rhinocerotis (Cooke) Ryvarden (Tiger Milk mushroom) is used as a traditional medicine to relieve cough, asthma and chronic hepatitis. The traditional uses of the sclerotium are presumably related to its anti-inflammatory effect. The present study was carried out to evaluate the anti-inflammatory activity of the sclerotial powder of L. rhinocerotis (Cooke) Ryvarden (Tiger Milk mushroom) cultivar TM02.
Fulltext A review of feature extraction software for microarray gene expression data

Tan CS, Ting WS, Mohamad MS, Chan WH, Deris S, Shah ZA

Biomed Res Int, 2014;2014:213656.
PMID: 25250315 DOI: 10.1155/2014/213656

When gene expression data are too large to be processed, they are transformed into a reduced representation set of genes. Transforming large-scale gene expression data into a set of genes is called feature extraction. If the genes extracted are carefully chosen, this gene set can extract the relevant information from the large-scale gene expression data, allowing further analysis by using this reduced representation instead of the full size data. In this paper, we review numerous software applications that can be used for feature extraction. The software reviewed is mainly for Principal Component Analysis (PCA), Independent Component Analysis (ICA), Partial Least Squares (PLS), and Local Linear Embedding (LLE). A summary and sources of the software are provided in the last section for each feature extraction method.
Fulltext Energy and nutritional composition of Tiger milk mushroom (Lignosus tigris Chon S. Tan) sclerotia and the antioxidant activity of its extracts

Yap HY, Aziz AA, Fung SY, Ng ST, Tan CS, Tan NH

Int J Med Sci, 2014;11(6):602-7.
PMID: 24782649 DOI: 10.7150/ijms.8341

The Lignosus is a genus of fungi that have useful medicinal properties. In Southeast Asia, three species of Lignosus (locally known collectively as Tiger milk mushrooms) have been reported including L. tigris, L. rhinocerotis, and L. cameronensis. All three have been used as important medicinal mushrooms by the natives of Peninsular Malaysia. In this work, the nutritional composition and antioxidant activities of the wild type and a cultivated strain of L. tigris sclerotial extracts were investigated. The sclerotia are rich in carbohydrates with moderate amount of protein and low fat content. Free radical scavenging activities of L. tigris sclerotial extracts correlate with their phenolic content, which ranges from 6.25 to 45.42 mg GAE/g extract. The FRAP values ranged from 0.002 to 0.041 mmol/min/g extract, while the DPPH(•), ABTS(•+), and superoxide anion (SOA) scavenging activities ranged from 0.18 to 2.53, 0.01 to 0.36, and -4.53 to 10.05 mmol Trolox equivalents/g extract, respectively. L. tigris cultivar shows good prospect to be developed into functional food due to its good nutritional value and potent SOA scavenging activity.
Fulltext Using project performance to measure effectiveness of quality management system maintenance and practices in construction industry

Leong TK, Zakuan N, Mat Saman MZ, Ariff MS, Tan CS

ScientificWorldJournal, 2014;2014:591361.
PMID: 24701182 DOI: 10.1155/2014/591361

This paper proposed seven existing and new performance indicators to measure the effectiveness of quality management system (QMS) maintenance and practices in construction industry. This research is carried out with a questionnaire based on QMS variables which are extracted from literature review and project performance indicators which are established from project management's theory. Data collected was analyzed using correlation and regression analysis. The findings indicate that client satisfaction and time variance have positive and significant relationship with QMS while other project performance indicators do not show significant results. Further studies can use the same project performance indicators to study the effectiveness of QMS in different sampling area to improve the generalizability of the findings.
Fulltext Review on cold-formed steel connections

Lee YH, Tan CS, Mohammad S, Tahir MM, Shek PN

ScientificWorldJournal, 2014;2014:951216.
PMID: 24688448 DOI: 10.1155/2014/951216

The concept of cold-formed light steel framing construction has been widespread after understanding its structural characteristics with massive research works over the years. Connection serves as one of the important elements for light steel framing in order to achieve its structural stability. Compared to hot-rolled steel sections, cold-formed steel connections perform dissimilarity due to the thin-walled behaviour. This paper aims to review current researches on cold-formed steel connections, particularly for screw connections, storage rack connections, welded connections, and bolted connections. The performance of these connections in the design of cold-formed steel structures is discussed.
Quantitation of green fluorescent protein using a gel-based imaging method

Chew FN, Tan WS, Ling TC, Tan CS, Tey BT

Anal Biochem, 2009 Jan 15;384(2):353-5.
PMID: 18952038 DOI: 10.1016/j.ab.2008.10.010

Green fluorescent protein (GFP) is a versatile reporter protein and has been widely used in biological research. However, its quantitation requires expensive equipment such as a spectrofluorometer. In the current study, a gel documentation imaging system using a native polyacrylamide gel for the quantitation of GFP was developed. The assay was evaluated for its precision, linearity, reproducibility, and sensitivity in the presence of Escherichia coli cells and was compared with the spectrofluorometric method. Using this newly established, gel-based imaging technique; the amount of GFP can be quantified accurately.
Shotgun proteomic analysis of tiger milk mushroom (Lignosus rhinocerotis) and the isolation of a cytotoxic fungal serine protease from its sclerotium

Yap HY, Fung SY, Ng ST, Tan CS, Tan NH

J Ethnopharmacol, 2015 Nov 4;174:437-51.
PMID: 26320692 DOI: 10.1016/j.jep.2015.08.042

The sclerotium of Lignosus rhinocerotis (Cooke) Ryvarden (tiger milk mushroom) has been traditionally used as a complementary and alternative medicine for cancer treatment by the local communities of Southeast Asia. Despite the continuous research interest in its antiproliferative activity, the identity of the bioactive compound(s) responsible has yet to be determined. This study aims to bridge the gap in existing research literature by using proteomics approach for investigation of the nature of the anticancer substance of L. rhinocerotis.
Fulltext Overview of Antagonists Used for Determining the Mechanisms of Action Employed by Potential Vasodilators with Their Suggested Signaling Pathways

Loh YC, Tan CS, Ch'ng YS, Ahmad M, Asmawi MZ, Yam MF

Molecules, 2016 Apr 15;21(4):495.
PMID: 27092479 DOI: 10.3390/molecules21040495

This paper is a review on the types of antagonists and the signaling mechanism pathways that have been used to determine the mechanisms of action employed for vasodilation by test compounds. Thus, we exhaustively reviewed and analyzed reports related to this topic published in PubMed between the years of 2010 till 2015. The aim of this paperis to suggest the most appropriate type of antagonists that correspond to receptors that would be involved during the mechanistic studies, as well as the latest signaling pathways trends that are being studied in order to determine the route(s) that atest compound employs for inducing vasodilation. The methods to perform the mechanism studies were included. Fundamentally, the affinity, specificity and selectivity of the antagonists to their receptors or enzymes were clearly elaborated as well as the solubility and reversibility. All the signaling pathways on the mechanisms of action involved in the vascular tone regulation have been well described in previous review articles. However, the most appropriate antagonists that should be utilized have never been suggested and elaborated before, hence the reason for this review.
Production of the virus-like particles of nipah virus matrix protein in Pichia pastoris as diagnostic reagents

Joseph NM, Ho KL, Tey BT, Tan CS, Shafee N, Tan WS

Biotechnol Prog, 2016 Jul 08;32(4):1038-45.
PMID: 27088434 DOI: 10.1002/btpr.2279

The matrix (M) protein of Nipah virus (NiV) is a peripheral protein that plays a vital role in the envelopment of nucleocapsid protein and acts as a bridge between the viral surface and the nucleocapsid proteins. The M protein is also proven to play an important role in production of virus-like particles (VLPs) and is essential for assembly and budding of NiV particles. The recombinant M protein produced in Escherichia coli assembled into VLPs in the absence of the viral surface proteins. However, the E. coli produced VLPs are smaller than the native virus particles. Therefore, the aims of this study were to produce NiV M protein in Pichia pastoris, to examine the structure of the VLPs formed, and to assess the potential of the VLPs as a diagnostic reagent. The M protein was successfully expressed in P. pastoris and was detected with anti-myc antibody using Western blotting. The VLPs formed by the recombinant M protein were purified with sucrose density gradient ultracentrifugation, high-performance liquid chromatography (HPLC), and Immobilized Metal Affinity Chromatography (IMAC). Immunogold staining and transmission electron microscopy confirmed that the M protein assembled into VLPs as large as 200 nm. ELISA revealed that the NiV M protein produced in P. pastoris reacted strongly with positive NiV sera demonstrating its potential as a diagnostic reagent. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1038-1045, 2016.
Diabetes telemonitoring reduces the risk of hypoglycaemia during Ramadan: a pilot randomized controlled study

Lee JY, Lee SW, Nasir NH, How S, Tan CS, Wong CP

Diabet Med, 2015 Dec;32(12):1658-61.
PMID: 26103794 DOI: 10.1111/dme.12836

AIM: This pilot study evaluated the short-term benefits of a telemonitoring-supplemented focused diabetic education compared with education alone in participants with Type 2 diabetes who were fasting during Ramadan.
METHODS: In this pilot mixed-method study, we identified 37 participants and randomly allocated them to either a telemonitoring group (n = 18) or a group receiving Ramadan-focused pre-education only (usual care; n = 19). The telemonitoring group received goal-setting and personalized feedback.
RESULTS: The telemonitoring group was less likely to experience hypoglycaemia than the usual care group (odds ratio: 0.1273; 95% confidence interval: 0.0267-0.6059). No significant differences were noted in glycaemic control at the end of study. Participants viewed telemedicine as a more convenient alternative although technological barriers remain a concern.
CONCLUSIONS: The results of this study reinforce the need for monitoring as well as educational initiatives for Muslims with diabetes who fast during Ramadan. Telemonitoring offers an attractive option requiring further research. (Clinical Trial Registry No. NCT02189135).
Nutritional evaluation on Lignosus cameronensis C. S. Tan, a medicinal Polyporaceae

Fung SY, Cheong PCH, Tan NH, Ng ST, Tan CS

IUBMB Life, 2019 07;71(7):821-826.
PMID: 30629799 DOI: 10.1002/iub.2006

Sclerotial powder of a cultivated species of the Tiger Milk Mushroom, Lignosus cameronensis was analysed for its nutritional components and compared against species of the same genus, Lignosus rhinocerus and Lignosus tigris. All three species have been used by indigenous tribes in Peninsular Malaysia as medicinal mushrooms. Content of carbohydrate, fibre, mineral, amino acid, palatable index, fat, ash and moisture were determined. L. cameronensis sclerotial material consists of carbohydrate (79.7%), protein (12.4%) and dietary fibre (5.4%) with low fat (1.7%) and no free sugar. It has the highest content of total carbohydrate (791 g kg-1 ), energy value (3,700 kcal kg-1 ) and calcium (0.85 g kg-1 ). The crude protein content (123 g kg-1 ) is comparable to that of L. rhinocerus with its main amino acids consisting of glutamic acid, aspartic acid and leucine. The umami index is determined to be 0.27. The total essential amino acid (45 g kg-1 ) is comparable to that of L. tigris. The main mineral is potassium (1.51 g kg-1 ) and the Na/K ratio was <0.6. Heavy metals such as mercury, cadmium, lead and arsenic were absent. L. cameronensis has the highest amount of food energy, total carbohydrate and calcium compared to those of both L. rhinocerus and L. tigris. The essential amino acids comprised almost 40% of the total amino acid content, slightly more than that reported from sclerotial powder of the L. tigris. © 2019 IUBMB Life, 9999(9999):1-6, 2019.
Associations between psychological factors and accelerometer-measured physical activity in urban Asian adults

Müller AM, Tan CS, Chu AHY, van Dam RM, Müller-Riemenschneider F

Int J Public Health, 2019 Jun;64(5):659-668.
PMID: 30739208 DOI: 10.1007/s00038-019-01203-6

OBJECTIVES: Examine the association between psychological variables and accelerometer-measured moderate-to-vigorous physical activity (MVPA) in urban Asians.
METHODS: A population-based cross-sectional study was conducted in Singapore. Participants wore an accelerometer for 7 days to measure physical activity (PA). Demographic, anthropometric and psychological data were also collected. Psychological variables included PA guideline knowledge, motivational profile for PA self-regulation (5 subscales), perceived barriers to PA (4 subscales) and perceived social support for PA. Regression models with adjustment for socio-demographic variables were fitted.
RESULTS: External regulation (b = - 13.03, 95% CI - 34.55; - 1.50) and perceived daily life barriers (b = - 12.63, 95% CI - 24.95; - 0.32) were significantly associated with fewer weekly MVPA minutes. A significant interaction between perceived social support and age (p = 0.046) was found. Social support was significantly negative associated with MVPA minutes in younger (
Fulltext Public and private sectors collective response to combat COVID-19 in Malaysia

Tan CS, Lokman S, Rao Y, Kok SH, Ming LC

J Pharm Policy Pract, 2021 May 03;14(1):40.
PMID: 33941265 DOI: 10.1186/s40545-021-00322-x

Over the last year, the dangerous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread rapidly around the world. Malaysia has not been excluded from this COVID-19 pandemic. The resurgence of COVID-19 cases has overwhelmed the public healthcare system and overloaded the healthcare resources. Ministry of Health (MOH) Malaysia has adopted an Emergency Ordinance (EO) to instruct private hospitals to receive both COVID-19 and non-COVID-19 patients to reduce the strain on public facilities. The treatment of COVID-19 patients at private hospitals could help to boost the bed and critical care occupancy. However, with the absence of insurance coverage because COVID-19 is categorised as pandemic-related diseases, there are some challenges and opportunities posed by the treatment fees management. Another major issue in the collaboration between public and private hospitals is the willingness of private medical consultants to participate in the management of COVID-19 patients, because medical consultants in private hospitals in Malaysia are not hospital employees, but what are termed "private contractors" who provide patient care services to the hospitals. Other collaborative measures with private healthcare providers, e.g. tele-conferencing by private medical clinics to monitor COVID-19 patients and the rollout of national vaccination programme. The public and private healthcare partnership must be enhanced, and continue to find effective ways to collaborate further to combat the pandemic. The MOH, private healthcare sectors and insurance providers need to have a synergistic COVID-19 treatment plans to ensure public as well as insurance policy holders have equal opportunities for COVID-19 screening tests, vaccinations and treatment.
Fulltext Proteins from Lignosus tigris with selective apoptotic cytotoxicity towards MCF7 cell line and suppresses MCF7-xenograft tumor growth

Kong BH, Teoh KH, Tan NH, Tan CS, Ng ST, Fung SY

PeerJ, 2020;8:e9650.
PMID: 32832273 DOI: 10.7717/peerj.9650

Background: Lignosus tigris, a recently discovered species of the unique Lignosus family, has been traditionally used by the indigenous communities in Peninsular Malaysia to treat various ailments and as an alternative medicine for cancer treatment. The L. tigris cultivar sclerotia (Ligno TG-K) was found to contain numerous bioactive compounds with beneficial biomedicinal properties and the sclerotial extract exhibited potent antioxidant activity. However, the anticancer property of the Ligno TG-K including in vitro and in vivo antitumor effects as well as its anticancer active compounds and the mechanisms has yet to be investigated.
Methods: The cytotoxicity of the Ligno TG-K against human breast (MCF7), prostate (PC3) and lung (A549) adenocarcinoma cell lines was evaluated using MTT cytotoxicity assay. The cytotoxic mechanisms of the active high molecular weight proteins (HMWp) fraction were investigated through detection of caspases activity and apoptotic-related proteins expression by Western blotting. The in vivo antitumor activity of the isolated HMWp was examined using MCF7 mouse xenograft model. Shotgun LC-MS/MS analysis was performed to identify the proteins in the HMWp.
Results and Discussion: Cold water extract of the sclerotia inhibited proliferation of MCF7, A549 and PC3 cells with IC50 ranged from 28.9 to 95.0 µg/mL. Bioassay guided fractionation of the extract revealed that HMWp exhibited selective cytotoxicity against MCF7 cells via induction of cellular apoptosis by the activation of extrinsic and intrinsic signaling pathways. HMWp activated expression of caspase-8 and -9 enzymes, and pro-apoptotic Bax protein whilst inhibiting expression of tumor survivor protein, Bcl-2. HMWp induced tumor-cell apoptosis and suppressed growth of tumor in MCF-7 xenograft mice. Lectins, serine proteases, RNase Gf29 and a 230NA deoxyribonuclease are the major cytotoxic proteins that accounted for 55.93% of the HMWp.
Conclusion: The findings from this study provided scientific evidences to support the traditional use of the L. tigris sclerotia for treatment of breast cancer. Several cytotoxic proteins with high abundance have been identified in the HMWp of the sclerotial extract and these proteins have potential to be developed into new anticancer agents or as adjunct cancer therapy.
Structural and kinetic studies of a novel nerol dehydrogenase from Persicaria minor, a nerol-specific enzyme for citral biosynthesis

Tan CS, Hassan M, Mohamed Hussein ZA, Ismail I, Ho KL, Ng CL, et al.

Plant Physiol Biochem, 2018 Feb;123:359-368.
PMID: 29304481 DOI: 10.1016/j.plaphy.2017.12.033

Geraniol degradation pathway has long been elucidated in microorganisms through bioconversion studies, yet weakly characterised in plants; enzyme with specific nerol-oxidising activity has not been reported. A novel cDNA encodes nerol dehydrogenase (PmNeDH) was isolated from Persicaria minor. The recombinant PmNeDH (rPmNeDH) is a homodimeric enzyme that belongs to MDR (medium-chain dehydrogenases/reductases) superfamily that catalyses the first oxidative step of geraniol degradation pathway in citral biosynthesis. Kinetic analysis revealed that rPmNeDH has a high specificity for allylic primary alcohols with backbone ≤10 carbons. rPmNeDH has ∼3 fold higher affinity towards nerol (cis-3,7-dimethyl-2,6-octadien-1-ol) than its trans-isomer, geraniol. To our knowledge, this is the first alcohol dehydrogenase with higher preference towards nerol, suggesting that nerol can be effective substrate for citral biosynthesis in P. minor. The rPmNeDH crystal structure (1.54 Å) showed high similarity with enzyme structures from MDR superfamily. Structure guided mutation was conducted to describe the relationships between substrate specificity and residue substitutions in the active site. Kinetics analyses of wild-type rPmNeDH and several active site mutants demonstrated that the substrate specificity of rPmNeDH can be altered by changing any selected active site residues (Asp280, Leu294 and Ala303). Interestingly, the L294F, A303F and A303G mutants were able to revamp the substrate preference towards geraniol. Furthermore, mutant that exhibited a broader substrate range was also obtained. This study demonstrates that P. minor may have evolved to contain enzyme that optimally recognise cis-configured nerol as substrate. rPmNeDH structure provides new insights into the substrate specificity and active site plasticity in MDR superfamily.

Filters

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

External Links