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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.
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 Molecular attributes and apoptosis-inducing activities of a putative serine protease isolated from Tiger Milk mushroom (Lignosus rhinocerus) sclerotium against breast cancer cells in vitro

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

PeerJ, 2018;6:e4940.
PMID: 29888137 DOI: 10.7717/peerj.4940

Background: The highly valued medicinal tiger milk mushroom (also known as Lignosus rhinocerus) has the ability to cure numerous ailments. Its anticancer activities are well explored, and recently a partially purified cytotoxic protein fraction termed F5 from the mushroom's sclerotial cold water extract consisting mainly of fungal serine proteases was found to exhibit potent selective cytotoxicity against a human breast adenocarcinoma cell line (MCF7) with IC50 value of 3.00 μg/ml. However, characterization of its cell death-inducing activity has yet to be established.
Methods: The mechanism involved in the cytotoxic activities of F5 against MCF7 cells was elucidated by flow cytometry-based apoptosis detection, caspases activity measurement, and expression profiling of apoptosis markers by western blotting. Molecular attributes of F5 were further mined from L. rhinocerus's published genome and transcriptome for future exploration.
Results and Discussion: Apoptosis induction in MCF7 cells by F5 may involve a cross-talk between the extrinsic and intrinsic apoptotic pathways with upregulation of caspase-8 and -9 activities and a marked decrease of Bcl-2. On the other hand, the levels of pro-apoptotic Bax, BID, and cleaved BID were increased accompanied by observable actin cleavage. At gene level, F5 composed of three predicted non-synonymous single nucleotide polymorphisms (T > C) and an alternative 5' splice site.
Conclusions: Findings from this study provide an advanced framework for further investigations on cancer therapeutics development from L. rhinocerus.
Fulltext Inhibition of Protein Glycation by Tiger Milk Mushroom [Lignosus rhinocerus(Cooke) Ryvarden] and Search for Potential Anti-diabetic Activity-Related Metabolic Pathways by Genomic and Transcriptomic Data Mining

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

Front Pharmacol, 2018;9:103.
PMID: 29491836 DOI: 10.3389/fphar.2018.00103

Naturally occurring anti-glycation compounds have drawn much interest in recent years as they show potential in reducing or preventing the risk of chronic complications for diabetic patients. In this study, annotation of the genome-transcriptome data from tiger milk mushroom (Lignosus rhinocerus, syn.Lignosus rhinocerotis) to PlantCyc enzymes database identified transcripts that are related to anti-diabetic properties, and these include genes that are involved in carotenoid and abscisic acid biosynthesis as well as genes that code for glyoxalase I, catalase-peroxidases, and superoxide dismutases. The existence of these genes suggests thatL. rhinocerusmay contain bioactive compound(s) with anti-glycation properties that can be exploited for management of diabetic complications. A medium-molecular-weight (MMW) fraction which was obtained from a combination of cold water extraction and Sephadex®G-50 (fine) gel filtration chromatography ofL. rhinocerussclerotia powder was demonstrated to exhibit potent anti-glycation activity. The fraction specifically inhibited the formation of N𝜀-(carboxymethyl)lysine, pentosidine, and other advanced glycation end-product (AGE) structures in a human serum albumin-glucose system, with an IC50value of 0.001 mg/ml, almost 520 times lower than that of the positive control, aminoguanidine hydrochloride (IC50= 0.52 mg/ml). Its ability to suppress protein glycation may be partly associated with its strong superoxide anion radical scavenging activity (10.16 ± 0.12 mmol TE/g). Our results suggest that the MMW fraction ofL. rhinocerusshows potential to be developed into a potent glycation inhibitor for preventing AGE-mediated diabetic complications.
Fulltext The Wound Healing Potential of Lignosus rhinocerus and Other Ethno-myco Wound Healing Agents

Yap HY, Ariffeen Rosli MF, Tan SH, Kong BH, Fung SY

Mycobiology, 2023;51(1):1-15.
PMID: 36846625 DOI: 10.1080/12298093.2022.2164641

Wound care has become increasingly important over the years. Various synthetic products for wound care treatment have been reported to cause toxic side effects and therefore natural products are in significant demand as they have minimal side effects. The presence of bioactive compounds in medicinal mushrooms contributes to various biological activities which assist in the early inflammatory phase, keratinocyte proliferation, and its migration enhancement which are pertinent to wound rehabilitation. Lignosus rhinocerus (tiger milk mushroom) can reduce the inflammation phase in wound healing by fighting off bacterial infection and modulating pro-inflammatory cytokines expression in the early stage to avoid prolonged inflammation and tissue damage. The antibacterial, immunomodulating, and anti-inflammatory activities exhibited by most macrofungi play a key role in enhancing wound healing. Several antibacterial and antifungal compounds sourced from traditional botanicals/products may prevent further complications and reoccurrence of injury to a wounded site. Scientific studies are actively underway to ascertain the potential use of macrofungi as a wound healing agent.
Fulltext The genome of the Tiger Milk mushroom, Lignosus rhinocerotis, provides insights into the genetic basis of its medicinal properties

Yap HY, Chooi YH, Firdaus-Raih M, Fung SY, Ng ST, Tan CS, et al.

BMC Genomics, 2014;15:635.
PMID: 25073817 DOI: 10.1186/1471-2164-15-635

The sclerotium of Lignosus rhinocerotis (Cooke) Ryvarden or Tiger milk mushroom (Polyporales, Basidiomycota) is a valuable folk medicine for indigenous peoples in Southeast Asia. Despite the increasing interest in this ethnobotanical mushroom, very little is known about the molecular and genetic basis of its medicinal and nutraceutical properties.
Fulltext An assessment of oral cancer knowledge, attitudes, and practices among undergraduate students in Malaysian dental schools

Chan ZW, Phuan YF, Ooi PY, Nor Azmi N, Pateel DGS, Yap HY, et al.

BMC Oral Health, 2023 Aug 31;23(1):617.
PMID: 37653402 DOI: 10.1186/s12903-023-03354-8

BACKGROUND: Oral cancer is a significant public health concern worldwide. Early detection and prevention are crucial in reducing the morbidity and mortality rates associated with this disease. As future dental professionals, dental undergraduates play a vital role in promoting oral health and identifying potential oral cancer cases.
METHODS: This study aimed to evaluate the level of oral cancer awareness, knowledge, attitudes, and practices among dental undergraduates in Malaysia. A total of 595 students from years 3, 4, and 5 in both public and private universities participated.
RESULTS: The results showed that a higher percentage of dental undergraduates from private universities were aware of oral cancer and had satisfactory knowledge compared to those from public universities (p
Fulltext Volatile Molecules Secreted by the Wheat Pathogen Parastagonospora nodorum Are Involved in Development and Phytotoxicity

Muria-Gonzalez MJ, Yeng Y, Breen S, Mead O, Wang C, Chooi YH, et al.

Front Microbiol, 2020;11:466.
PMID: 32269554 DOI: 10.3389/fmicb.2020.00466

Septoria nodorum blotch is a major disease of wheat caused by the fungus Parastagonospora nodorum. Recent studies have demonstrated that secondary metabolites, including polyketides and non-ribosomal peptides, produced by the pathogen play important roles in disease and development. However, there is currently no knowledge on the composition or biological activity of the volatile organic compounds (VOCs) secreted by P. nodorum. To address this, we undertook a series of growth and phytotoxicity assays and demonstrated that P. nodorum VOCs inhibited bacterial growth, were phytotoxic and suppressed self-growth. Mass spectrometry analysis revealed that 3-methyl-1-butanol, 2-methyl-1-butanol, 2-methyl-1-propanol, and 2-phenylethanol were dominant in the VOC mixture and phenotypic assays using these short chain alcohols confirmed that they were phytotoxic. Further analysis of the VOCs also identified the presence of multiple sesquiterpenes of which four were identified via mass spectrometry and nuclear magnetic resonance as β-elemene, α-cyperone, eudesma-4,11-diene and acora-4,9-diene. Subsequent reverse genetics studies were able to link these molecules to corresponding sesquiterpene synthases in the P. nodorum genome. However, despite extensive testing, these molecules were not involved in either of the growth inhibition or phytotoxicity phenotypes previously observed. Plant assays using mutants of the pathogen lacking the synthetic genes revealed that the identified sesquiterpenes were not required for disease formation on wheat leaves. Collectively, these data have significantly extended our knowledge of the VOCs in fungi and provided the basis for further dissecting the roles of sesquiterpenes in plant disease.