Yee Shin Tan | University of Malaya, Malaysia (original) (raw)

Papers by Yee Shin Tan

Journal of Applied Microbiology

International journal of medicinal mushrooms, 2018

Five culinary-medicinal mushrooms are commonly available in the Malaysian market: Agaricus bispor... more Five culinary-medicinal mushrooms are commonly available in the Malaysian market: Agaricus bisporus (white and brown), Ganoderma lucidum, Hypsizygus marmoreus, Pleurotus floridanus, and P. pulmonarius. These species were selected for use in the current study, the aim of which was to investigate the antimelanogenesis and anti-inflammatory activity of these mushrooms in an attempt to evaluate their potential use in cosmeceuticals. Mushroom fruiting bodies were extracted with hot water, and the extracts were freeze-dried before testing. The antimelanogenesis activity of the extracts was determined by cell viability assay, measurement of intracellular melanin content, and cellular tyrosinase assay with B16F10 melanoma cells. The anti-inflammatory activity of the mushroom extracts was tested by measuring the levels of nitric oxide (NO), tumor necrosis factor (TNF)-α, and interleukin-10 excreted by RAW264.7 macrophages. Brown A. bisporus reduced intracellular melanin content to the larges...

International Journal of Medicinal Mushrooms

International journal of medicinal mushrooms, 2017

Amauroderma rugosum is a wild medicinal mushroom also known as budak cendawan sawan. Members of t... more Amauroderma rugosum is a wild medicinal mushroom also known as budak cendawan sawan. Members of the indigenous Malaysian Temuan community wear the fresh stipes as a necklace to prevent epileptic seizure and unremitting crying by babies. In our previous studies, A. rugosum exhibited significant antioxidant and anti-inflammatory activities. The aim of this study was to determine the toxicity (in the event that a stipe is accidentally bitten) and cytotoxicity of this mushroom on Sprague-Dawley rats and selected cell lines. A. rugosum was orally administered to test chemicals according to Organisation for Economic and Co-operation and Development guidelines (TG 425, adopted October 3, 2008). Blood samples were hematologically and biochemically analyzed and multiple tissue sections from each organ were examined using light microscopy. Cytotoxicity of various A. rugosum extracts was also determined against MCF-7 and A-549 cell lines. Our results showed that oral administration of a single...

Journal of Bioscience and Bioengineering

Amauroderma rugosum is a wild mushroom species widely distributed in tropics and is classified un... more Amauroderma rugosum is a wild mushroom species widely distributed in tropics and is classified under the class of Basidiomycetes. Basidiomycetes are well-known for their abilities of producing lignocellulolytic enzymes such as lignin peroxidase (LiP), laccase (Lac) and manganese peroxidase (MnP). Different factors such as nutrient sources, incubation period and agitation affect the production of lignocellulolytic enzymes. The A. rugosum produced LiP in the medium supplemented with potato dextrose broth (PDB), 0.5% yeast and 1.0% saw dust at 26.70±3.31 U/mL. However, the LiP activity was increased to 106.32±5.32 U/mL when supplemented with 150 μm of copper (CuSO). The aqueous two-phase system (ATPS) is a simple, rapid and low cost method for primary extraction and recovery of LiP. A total of 25 systems made from five different molecular weights of polyethylene glycol (PEG)/dipotassium hydrogen phosphate (KHPO) were tested. PEG 600 produced the highest top phase purification factor (P) of 1.33±0.62 with yield of 72.18±8.50%. The optimization of the ATPS parameters, such as volume ratio V, pH and crude enzyme loading are the factors controlling the phase partition. Our results showed that significant improvement (P of 6.26±2.87 with yield of 87.31±3.14%) of LiP recovery can be achieved by optimized the parameters.

Scientific reports, Jul 20, 2016

The discovery of semiconducting behavior of deoxyribonucleic acid (DNA) has resulted in a large n... more The discovery of semiconducting behavior of deoxyribonucleic acid (DNA) has resulted in a large number of literatures in the study of DNA electronics. Sequence-specific electronic response provides a platform towards understanding charge transfer mechanism and therefore the electronic properties of DNA. It is possible to utilize these characteristic properties to identify/detect DNA. In this current work, we demonstrate a novel method of DNA-based identification of basidiomycetes using current-voltage (I-V) profiles obtained from DNA-specific Schottky barrier diodes. Electronic properties such as ideality factor, barrier height, shunt resistance, series resistance, turn-on voltage, knee-voltage, breakdown voltage and breakdown current were calculated and used to quantify the identification process as compared to morphological and molecular characterization techniques. The use of these techniques is necessary in order to study biodiversity, but sometimes it can be misleading and unre...

Japs Journal of Animal and Plant Sciences, Feb 16, 2014

World Journal of Microbiology and Biotechnology, 2016

PLOS ONE, 2015

Amauroderma rugosum, commonly known as "Jiǎzī" ... more Amauroderma rugosum, commonly known as "Jiǎzī" in China, is a wild mushroom traditionally used by the Chinese to reduce inflammation, to treat diuretic and upset stomach, and to prevent cancer. It is also used by the indigenous communities in Malaysia to prevent epileptic episodes and incessant crying by babies. The aim of this study was to compare the wild and domesticated basidiocarps of A. rugosum for antioxidant and in vitro anti-inflammatory effects in LPS-stimulated RAW264.7 cells. The wild basidiocarps of A. rugosum were collected from the Belum Forest, Perak, Malaysia and the domesticated basidiocarps of A. rugosum were cultivated in the mushroom house located in the University of Malaya, Kuala Lumpur, Malaysia. Both the wild and domesticated basidiocarps were subjected to ethanolic extraction and the extracts were tested for antioxidant and anti-inflammatory activities. In this study, the crude ethanolic extract of wild (WB) and domesticated (DB) basidiocarps of A. rugosum had comparable total phenolic content and DPPH scavenging activity. However, WB (EC50 = 222.90 μg/mL) displayed a better ABTS cation radical scavenging activity than DB (EC50 = 469.60 μg/mL). Both WB and DB were able to scavenge nitric oxide (NO) radical and suppress the NO production in LPS-stimulated RAW264.7 cells and this effect was mediated through the down-regulation of inducible nitric oxide synthase (iNOS) gene. In addition, both WB and DB caused down-regulation of the inflammatory gene TNF-α and the up-regulation of the anti-inflammatory gene IL-10. There was no inhibitory effect of WB and DB on nuclear translocation of NF-κB p65. In conclusion, the wild and domesticated basidiocarps of A. rugosum possessed antioxidant and in vitro anti-inflammatory properties. WB and DB inhibited downstream inflammatory mediators (TNF-α and NO) and induced anti-inflammatory cytokine IL-10 production. No inhibitory effects shown on upstream nuclear translocation of NF-κB p65. WB and DB exhibited antioxidant activity and attenuation of proinflammatory mediators and therefore, A. rugosum may serve as a potential therapeutic agent in the management of inflammation.

Members of the genus Marasmius (Basidiomycota, Agaricales, Marasmiaceae) are saprotrophic fungi o... more Members of the genus Marasmius (Basidiomycota, Agaricales, Marasmiaceae) are saprotrophic fungi often encountered in forests or disturbed areas on leaf litter, twigs and dead wood where they serve an important ecological role in biodegradation of lignocellulosic material. In Malaysia, the diversity and distribution of Marasmius species are poorly documented. Historically, over 120 species of Marasmius have been reported from Peninsular Malaysia but our type studies, recent fieldwork and laboratory studies indicate that most of these belong to other genera. Approximately 300 specimens of Marasmius were collected in lowland and highland forests in Peninsular Malaysia from January 2003 to April 2006. We currently recognize approximately 50 species of Marasmius sensu stricto from Peninsular Malaysia, of which about one third represent species new to science. The mating systems operating in 10 species were evaluated and found to be consistent at the sectional rank with data from temperat...

A total of 43 species of Marasmius sensu stricto belonging to six sections (Globulares, Hygrometr... more A total of 43 species of Marasmius sensu stricto belonging to six sections (Globulares, Hygrometrici, Leveilleani, Marasmius, Neosessiles and Sicci) are reported from Peninsular Malaysia. Macro- and micromorphological characters in combination with ITS sequence data were used to circumscribe species. Of the 43 species reported herein, 9 represent new species, viz., M. angustilamellatus, M. diminutivus, M. distantifolius, M. iras, M. kanchingensis, M. kuthubutheenii, M. musicolor, M. ochropoides, and M. olivascens. An additional 19 species are new records for Peninsular Malaysia. Phylogenetic analyses of 36 Malaysian Marasmius species were conducted based on sequence data from nrDNA ITS-1–5.8S–ITS-2 gene regions. The ITS data support the circumscription of species based on morphological characters and are useful in aiding species delimitations. The ITS data do not, however, support the current sectional delimitation of Marasmius wherein most sections are not monophyletic. Comprehensi...

Mycologia

Three new species and one new variety of bioluminescent Mycena collected from Peninsular Malaysia... more Three new species and one new variety of bioluminescent Mycena collected from Peninsular Malaysia are described herein. All new species belong to Mycena sect. Calodontes in what is known as the Mycena pura complex. Comprehensive descriptions, photographs, illustrations and comparisons with phenetically similar species are provided. Molecular sequences data from the nuclear internal transcribed spacers (ITS-1 and ITS-2, including the 5.8S rRNA) were used to infer relationships within sect. Calodontes. Axenic cultures were obtained to provide data on culture morphology. This is the first published photographic documentation of bioluminescent basidiomes of members of Mycena sect. Calodontes. Also, this addition brings the total known bioluminescent fungi to 77 species.

Applied Physics Express, 2015

The Scientific World Journal, 2014

Journal of Applied Microbiology

International journal of medicinal mushrooms, 2018

Five culinary-medicinal mushrooms are commonly available in the Malaysian market: Agaricus bispor... more Five culinary-medicinal mushrooms are commonly available in the Malaysian market: Agaricus bisporus (white and brown), Ganoderma lucidum, Hypsizygus marmoreus, Pleurotus floridanus, and P. pulmonarius. These species were selected for use in the current study, the aim of which was to investigate the antimelanogenesis and anti-inflammatory activity of these mushrooms in an attempt to evaluate their potential use in cosmeceuticals. Mushroom fruiting bodies were extracted with hot water, and the extracts were freeze-dried before testing. The antimelanogenesis activity of the extracts was determined by cell viability assay, measurement of intracellular melanin content, and cellular tyrosinase assay with B16F10 melanoma cells. The anti-inflammatory activity of the mushroom extracts was tested by measuring the levels of nitric oxide (NO), tumor necrosis factor (TNF)-α, and interleukin-10 excreted by RAW264.7 macrophages. Brown A. bisporus reduced intracellular melanin content to the larges...

International Journal of Medicinal Mushrooms

International journal of medicinal mushrooms, 2017

Amauroderma rugosum is a wild medicinal mushroom also known as budak cendawan sawan. Members of t... more Amauroderma rugosum is a wild medicinal mushroom also known as budak cendawan sawan. Members of the indigenous Malaysian Temuan community wear the fresh stipes as a necklace to prevent epileptic seizure and unremitting crying by babies. In our previous studies, A. rugosum exhibited significant antioxidant and anti-inflammatory activities. The aim of this study was to determine the toxicity (in the event that a stipe is accidentally bitten) and cytotoxicity of this mushroom on Sprague-Dawley rats and selected cell lines. A. rugosum was orally administered to test chemicals according to Organisation for Economic and Co-operation and Development guidelines (TG 425, adopted October 3, 2008). Blood samples were hematologically and biochemically analyzed and multiple tissue sections from each organ were examined using light microscopy. Cytotoxicity of various A. rugosum extracts was also determined against MCF-7 and A-549 cell lines. Our results showed that oral administration of a single...

Journal of Bioscience and Bioengineering

Amauroderma rugosum is a wild mushroom species widely distributed in tropics and is classified un... more Amauroderma rugosum is a wild mushroom species widely distributed in tropics and is classified under the class of Basidiomycetes. Basidiomycetes are well-known for their abilities of producing lignocellulolytic enzymes such as lignin peroxidase (LiP), laccase (Lac) and manganese peroxidase (MnP). Different factors such as nutrient sources, incubation period and agitation affect the production of lignocellulolytic enzymes. The A. rugosum produced LiP in the medium supplemented with potato dextrose broth (PDB), 0.5% yeast and 1.0% saw dust at 26.70±3.31 U/mL. However, the LiP activity was increased to 106.32±5.32 U/mL when supplemented with 150 μm of copper (CuSO). The aqueous two-phase system (ATPS) is a simple, rapid and low cost method for primary extraction and recovery of LiP. A total of 25 systems made from five different molecular weights of polyethylene glycol (PEG)/dipotassium hydrogen phosphate (KHPO) were tested. PEG 600 produced the highest top phase purification factor (P) of 1.33±0.62 with yield of 72.18±8.50%. The optimization of the ATPS parameters, such as volume ratio V, pH and crude enzyme loading are the factors controlling the phase partition. Our results showed that significant improvement (P of 6.26±2.87 with yield of 87.31±3.14%) of LiP recovery can be achieved by optimized the parameters.

Scientific reports, Jul 20, 2016

The discovery of semiconducting behavior of deoxyribonucleic acid (DNA) has resulted in a large n... more The discovery of semiconducting behavior of deoxyribonucleic acid (DNA) has resulted in a large number of literatures in the study of DNA electronics. Sequence-specific electronic response provides a platform towards understanding charge transfer mechanism and therefore the electronic properties of DNA. It is possible to utilize these characteristic properties to identify/detect DNA. In this current work, we demonstrate a novel method of DNA-based identification of basidiomycetes using current-voltage (I-V) profiles obtained from DNA-specific Schottky barrier diodes. Electronic properties such as ideality factor, barrier height, shunt resistance, series resistance, turn-on voltage, knee-voltage, breakdown voltage and breakdown current were calculated and used to quantify the identification process as compared to morphological and molecular characterization techniques. The use of these techniques is necessary in order to study biodiversity, but sometimes it can be misleading and unre...

Japs Journal of Animal and Plant Sciences, Feb 16, 2014

World Journal of Microbiology and Biotechnology, 2016

PLOS ONE, 2015

Amauroderma rugosum, commonly known as "Jiǎzī" ... more Amauroderma rugosum, commonly known as "Jiǎzī" in China, is a wild mushroom traditionally used by the Chinese to reduce inflammation, to treat diuretic and upset stomach, and to prevent cancer. It is also used by the indigenous communities in Malaysia to prevent epileptic episodes and incessant crying by babies. The aim of this study was to compare the wild and domesticated basidiocarps of A. rugosum for antioxidant and in vitro anti-inflammatory effects in LPS-stimulated RAW264.7 cells. The wild basidiocarps of A. rugosum were collected from the Belum Forest, Perak, Malaysia and the domesticated basidiocarps of A. rugosum were cultivated in the mushroom house located in the University of Malaya, Kuala Lumpur, Malaysia. Both the wild and domesticated basidiocarps were subjected to ethanolic extraction and the extracts were tested for antioxidant and anti-inflammatory activities. In this study, the crude ethanolic extract of wild (WB) and domesticated (DB) basidiocarps of A. rugosum had comparable total phenolic content and DPPH scavenging activity. However, WB (EC50 = 222.90 μg/mL) displayed a better ABTS cation radical scavenging activity than DB (EC50 = 469.60 μg/mL). Both WB and DB were able to scavenge nitric oxide (NO) radical and suppress the NO production in LPS-stimulated RAW264.7 cells and this effect was mediated through the down-regulation of inducible nitric oxide synthase (iNOS) gene. In addition, both WB and DB caused down-regulation of the inflammatory gene TNF-α and the up-regulation of the anti-inflammatory gene IL-10. There was no inhibitory effect of WB and DB on nuclear translocation of NF-κB p65. In conclusion, the wild and domesticated basidiocarps of A. rugosum possessed antioxidant and in vitro anti-inflammatory properties. WB and DB inhibited downstream inflammatory mediators (TNF-α and NO) and induced anti-inflammatory cytokine IL-10 production. No inhibitory effects shown on upstream nuclear translocation of NF-κB p65. WB and DB exhibited antioxidant activity and attenuation of proinflammatory mediators and therefore, A. rugosum may serve as a potential therapeutic agent in the management of inflammation.

Members of the genus Marasmius (Basidiomycota, Agaricales, Marasmiaceae) are saprotrophic fungi o... more Members of the genus Marasmius (Basidiomycota, Agaricales, Marasmiaceae) are saprotrophic fungi often encountered in forests or disturbed areas on leaf litter, twigs and dead wood where they serve an important ecological role in biodegradation of lignocellulosic material. In Malaysia, the diversity and distribution of Marasmius species are poorly documented. Historically, over 120 species of Marasmius have been reported from Peninsular Malaysia but our type studies, recent fieldwork and laboratory studies indicate that most of these belong to other genera. Approximately 300 specimens of Marasmius were collected in lowland and highland forests in Peninsular Malaysia from January 2003 to April 2006. We currently recognize approximately 50 species of Marasmius sensu stricto from Peninsular Malaysia, of which about one third represent species new to science. The mating systems operating in 10 species were evaluated and found to be consistent at the sectional rank with data from temperat...

A total of 43 species of Marasmius sensu stricto belonging to six sections (Globulares, Hygrometr... more A total of 43 species of Marasmius sensu stricto belonging to six sections (Globulares, Hygrometrici, Leveilleani, Marasmius, Neosessiles and Sicci) are reported from Peninsular Malaysia. Macro- and micromorphological characters in combination with ITS sequence data were used to circumscribe species. Of the 43 species reported herein, 9 represent new species, viz., M. angustilamellatus, M. diminutivus, M. distantifolius, M. iras, M. kanchingensis, M. kuthubutheenii, M. musicolor, M. ochropoides, and M. olivascens. An additional 19 species are new records for Peninsular Malaysia. Phylogenetic analyses of 36 Malaysian Marasmius species were conducted based on sequence data from nrDNA ITS-1–5.8S–ITS-2 gene regions. The ITS data support the circumscription of species based on morphological characters and are useful in aiding species delimitations. The ITS data do not, however, support the current sectional delimitation of Marasmius wherein most sections are not monophyletic. Comprehensi...

Mycologia

Three new species and one new variety of bioluminescent Mycena collected from Peninsular Malaysia... more Three new species and one new variety of bioluminescent Mycena collected from Peninsular Malaysia are described herein. All new species belong to Mycena sect. Calodontes in what is known as the Mycena pura complex. Comprehensive descriptions, photographs, illustrations and comparisons with phenetically similar species are provided. Molecular sequences data from the nuclear internal transcribed spacers (ITS-1 and ITS-2, including the 5.8S rRNA) were used to infer relationships within sect. Calodontes. Axenic cultures were obtained to provide data on culture morphology. This is the first published photographic documentation of bioluminescent basidiomes of members of Mycena sect. Calodontes. Also, this addition brings the total known bioluminescent fungi to 77 species.

Applied Physics Express, 2015

The Scientific World Journal, 2014