Learn-Han Lee

Prof. Dr. Learn-Han Lee

Novel Bacteria and Drug Discovery Research Group (NBDD), Microbes and Bioresource Research Strength (MBRS), Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, 47500 Bandar Sunway, Selangor, Malaysia
orcid

Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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12 January 2015 in Frontiers in Microbiology
Verified
Journal Article
Open access
PDF file
Jodi Woan-Fei Law LawJodi Woan-Fei Law Law
Jodi Woan-Fei Law Law
NMNurul-Syakima Ab Mutalib
Nurul-Syakima Ab Mutalib
Chan Kok GanChan Kok Gan
Chan Kok Gan
Learn-Han LeeLearn-Han Lee
Learn-Han Lee
The incidence of foodborne diseases has increased over the years and resulted in major public health problem globally. Foodborne pathogens can be found in various foods and it is important to detect foodborne pathogens to provide safe food supply and to prevent foodborne diseases. The conventional methods used to detect foodborne pathogen are time consuming and laborious. Hence, a variety of methods have been developed for rapid detection of foodborne pathogens as it is required in many food analyses. Rapid detection methods can be categorized into nucleic acid-based, biosensor-based and immunological-based methods. This review emphasizes on the principles and application of recent rapid methods for the detection of foodborne bacterial pathogens. Detection methods included are simple polymerase chain reaction (PCR), multiplex PCR, real-time PCR, nucleic acid sequence-based amplification (NASBA), loop-mediated isothermal amplification (LAMP) and oligonucleotide DNA microarray which classified as nucleic acid-based methods; optical, electrochemical and mass-based biosensors which classified as biosensor-based methods; enzyme-linked immunosorbent assay (ELISA) and lateral flow immunoassay which classified as immunological-based methods. In general, rapid detection methods are generally time-efficient, sensitive, specific and labor-saving. The developments of rapid detection methods are vital in prevention and treatment of foodborne diseases.

9 June 2015 in Frontiers in Life Science
Verified
Journal Article
Closed access
SEShu Kee Eng
Shu Kee Eng
PPPriyia Pusparajah
Priyia Pusparajah
NMNurul-Syakima Ab Mutalib
Nurul-Syakima Ab Mutalib
HSHooi-Leng Ser
Hooi-Leng Ser
Chan Kok GanChan Kok Gan
Chan Kok Gan
Learn-Han LeeLearn-Han Lee
Learn-Han Lee

26 January 2021 in Plants
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Journal Article
Open access
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Dora LawrenciaDora Lawrencia
Dora Lawrencia
SWSee Kiat Wong
See Kiat Wong
DLDarren Low
Darren Low
Bey Hing GohBey Hing Goh
Bey Hing Goh
JGJoo Kheng Goh
Joo Kheng Goh
Patrick Tang Siah YingPatrick Tang Siah Ying
Patrick Tang Siah Ying
Rising world population is expected to increase the demand for nitrogen fertilizers to improve crop yield and ensure food security. With existing challenges on low nutrient use efficiency (NUE) of urea and its environmental concerns, controlled release fertilizers (CRFs) have become a potential solution by formulating them to synchronize nutrient release according to the requirement of plants. However, the most significant challenge that persists is the “tailing” effect, which reduces the economic benefits in terms of maximum fertilizer utilization. High materials cost is also a significant obstacle restraining the widespread application of CRF in agriculture. The first part of this review covers issues related to the application of conventional fertilizer and CRFs in general. In the subsequent sections, different raw materials utilized to form CRFs, focusing on inorganic and organic materials and synthetic and natural polymers alongside their physical and chemical preparation methods, are compared. Important factors affecting rate of release, mechanism of release and mathematical modelling approaches to predict nutrient release are also discussed. This review aims to provide a better overview of the developments regarding CRFs in the past ten years, and trends are identified and analyzed to provide an insight for future works in the field of agriculture.

11 December 2014 in Frontiers in Microbiology
Verified
Journal Article
Open access
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VLVengadesh Letchumanan
Vengadesh Letchumanan
Chan Kok GanChan Kok Gan
Chan Kok Gan
Learn-Han LeeLearn-Han Lee
Learn-Han Lee
Vibrio parahaemolyticus is a Gram-negative halophilic bacterium that is found in estuarine, marine and coastal environments. Vibrio parahaemolyticus is the leading causal agent of human acute gastroenteritis following the consumption of raw, undercooked or mishandled marine products. In rare cases, Vibrio parahaemolyticus causes wound infection, ear infection or septicaemia in individuals with pre-existing medical conditions. Vibrio parahaemolyticus has two hemolysins virulence factors that are thermostable direct hemolysin (tdh)-a pore-forming protein that contributes to the invasiveness of the bacterium in humans, and TDH-related hemolysin (trh), which plays a similar role as thermostable direct hemolysin (tdh) in the disease pathogenesis. In addition, the bacterium is also encodes for adhesions and type III secretion systems (T3SS1 and T3SS2) to ensure its survival in the environment. This review aims at discussing the Vibrio parahemolyticus growth and characteristics, pathogenesis, prevalence and advances in molecular identification techniques.

28 April 2016 in Molecules
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Journal Article
Open access
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CKChan Weng Keong
Chan Weng Keong
LTLoh Teng-Hern Tan
Loh Teng-Hern Tan
Chan Kok GanChan Kok Gan
Chan Kok Gan
Learn-Han LeeLearn-Han Lee
Learn-Han Lee
Bey Hing GohBey Hing Goh
Bey Hing Goh
Nerolidol (3,7,11-trimethyl-1,6,10-dodecatrien-3-ol) is a naturally occurring sesquiterpene alcohol that is present in various plants with a floral odor. It is synthesized as an intermediate in the production of (3E)-4,8-dimethy-1,3,7-nonatriene (DMNT), a herbivore-induced volatile that protects plants from herbivore damage. Chemically, nerolidol exists in two geometric isomers, a trans and a cis form. The usage of nerolidol is widespread across different industries. It has been widely used in cosmetics (e.g., shampoos and perfumes) and in non-cosmetic products (e.g., detergents and cleansers). In fact, U.S. Food and Drug Administration (FDA) has also permitted the use of nerolidol as a food flavoring agent. The fact that nerolidol is a common ingredient in many products has attracted researchers to explore more medicinal properties of nerolidol that may exert beneficial effect on human health. Therefore, the aim of this review is to compile and consolidate the data on the various pharmacological and biological activities displayed by nerolidol. Furthermore, this review also includes pharmacokinetic and toxicological studies of nerolidol. In summary, the various pharmacological and biological activities demonstrated in this review highlight the prospects of nerolidol as a promising chemical or drug candidate in the field of agriculture and medicine.

27 September 2022 in Antioxidants
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Journal Article
Open access
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BSBAKRIM SAAD
BAKRIM SAAD
Nesrine BenkhairaNesrine Benkhaira
Nesrine Benkhaira
IBIlhame BOURAIS
Ilhame BOURAIS
TBTaoufiq Benali
Taoufiq Benali
Learn-Han LeeLearn-Han Lee
Learn-Han Lee
Abdelhakim BOUYAHYAAbdelhakim BOUYAHYA
Abdelhakim BOUYAHYA
Stigmasterol is an unsaturated phytosterol belonging to the class of tetracyclic triterpenes. It is one of the most common plant sterols, found in a variety of natural sources, including vegetable fats or oils from many plants. Currently, stigmasterol has been examined via in vitro and in vivo assays and molecular docking for its various biological activities on different metabolic disorders. The findings indicate potent pharmacological effects such as anticancer, anti-osteoarthritis, anti-inflammatory, anti-diabetic, immunomodulatory, antiparasitic, antifungal, antibacterial, antioxidant, and neuroprotective properties. Indeed, stigmasterol from plants and algae is a promising molecule in the development of drugs for cancer therapy by triggering intracellular signaling pathways in numerous cancers. It acts on the Akt/mTOR and JAK/STAT pathways in ovarian and gastric cancers. In addition, stigmasterol markedly disrupted angiogenesis in human cholangiocarcinoma by tumor necrosis factor-α (TNF-α) and vascular endothelial growth factor receptor-2 (VEGFR-2) signaling down-regulation. The association of stigmasterol and sorafenib promoted caspase-3 activity and down-regulated levels of the anti-apoptotic protein Bcl-2 in breast cancer. Antioxidant activities ensuring lipid peroxidation and DNA damage lowering conferred to stigmasterol chemoprotective activities in skin cancer. Reactive oxygen species (ROS) regulation also contributes to the neuroprotective effects of stigmasterol, as well as dopamine depletion and acetylcholinesterase inhibition. The anti-inflammatory properties of phytosterols involve the production of anti-inflammatory cytokines, the decrease in inflammatory mediator release, and the inhibition of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Stigmasterol exerts anti-diabetic effects by reducing fasting glucose, serum insulin levels, and oral glucose tolerance. Other findings showed the antiparasitic activities of this molecule against certain strains of parasites such as Trypanosoma congolense (in vivo) and on promastigotes and amastigotes of the Leishmania major (in vitro). Some stigmasterol-rich plants were able to inhibit Candida albicans, virusei, and tropicalis at low doses. Accordingly, this review outlines key insights into the pharmacological abilities of stigmasterol and the specific mechanisms of action underlying some of these effects. Additionally, further investigation regarding pharmacodynamics, pharmacokinetics, and toxicology is recommended.