Kok Gan Chan

Verified

Kok Gan verified their affiliation via an institutional email.

Learn more

Verified

Kok Gan verified their affiliation via an institutional email.

Learn more

• Doctor of Philosophy
• Professor (Full) at University of Malaya

Hot springs, with their well-characterized major abiotic variables and island-like habitats, are ideal systems for studying microbial biogeography. Photosynthetic biofilms are a major biological feature of hot springs but despite this large-scale studies are scarce, leaving critical questions about the drivers of spatial turnover unanswered. Here,...

Rhinovirus (RV), classified into RV‐A, RV‐B, and RV‐C, is a prevalent cause of respiratory tract infections (RTIs). Here, we analysed RV infection and its clinical implications among outpatients with acute upper RTIs. Demographic data, baseline comorbidities, clinical symptoms, and health outcomes of RV‐infected patients ( n = 849) were compared wi...

Traditional probiotics have been extensively studied, and their effectiveness in gut modulation is well established. However, emerging research has shifted focus to previously understudied probiotic strains, now known as next-generation probiotics (NGPs), with the aim of harnessing their unique potential to elicit targeted therapeutic effects in di...

Acinetobacter baumannii is a multidrug-resistant bacterium that has emerged as a significant nosocomial pathogen globally and renowned for its ability to acquire antimicrobial resistance (AMR) genes. However, understanding of its resistance mechanisms to certain drug classes remains limited. This study focused on four bacterial strains (AB863, AB88...

As an enduring hot topic in the field of innate immunity, apoptosis is widely considered an effective approach to eliminate pathogenic microbes and plays a crucial role during host–pathogen interactions. Recently, researchers have found that the virus-containing host cells could transmit apoptotic signals to the surrounding uninfected cells during...

Background Common cold coronaviruses (ccCoVs) and influenza virus are common infectious agents causing upper respiratory tract infections (RTIs). However, clinical symptoms, comorbidities, and health effects of ccCoV infection remain understudied. Methods A retrospective study evaluated 3,935 outpatients with acute upper RTI at a tertiary teaching...

Background Bacillus clausii possesses profound probiotic potential to alleviate gastrointestinal (GI) disorders, promote gut health, and fortify immune function. There is increasing interest in exploiting these beneficial properties beyond treating GI ailments. Therefore, this scoping review aims to investigate the potential of B. clausii as a prob...

The heteroplasmic mitogenome of the stingless bee Tetragonula laeviceps from Peninsular Malaysia consists of two variants (TL1-1 and TL1-2), both with 29,084 bp consisting of two segments: the “canonical” segment contains 36 genes—13 protein-coding genes (PCGs), 2 rRNA, and 21 tRNA genes; and the inverted repeat segment consists of 31 genes (11 PCG...

Bactrocera (Bulladacus) cinnabaria and B. (Bactrocera) propinqua are tephritid fruit flies of the subfamily Dacinae, tribe Dacini. The whole mitogenomes of these two species (first report for the subgenus Bulladacus) possess 37 genes (13 protein-coding genes – PCGs, 2 rRNA and 22 tRNA genes). The mitogenome of B. cinnabaria (15,225 bp) is shorter t...

Visualization of the spatiotemporal organization and dynamics of the genome in the nucleus is essential to elucidate how chromatin structure and nuclear function are intertwined. In the past, such studies were limited by the lack of appropriate tools. However, various imaging techniques now allow direct visualization of genomic loci in living cells...

Background Hot spring biofilms provide a window into the survival strategies of microbial communities in extreme environments and offer potential for biotechnological applications. This study focused on green and brown biofilms thriving on submerged plant litter within the Sungai Klah hot spring in Malaysia, characterised by temperatures of 58–74 °...

In this study, strain B2D isolated from a dental plaque sample of a human patient was studied for its general characteristics, taxonomic identification, genome features, and resistome profile. The bacterium exhibited antibiotic resistance to all beta-lactam antibiotics, nitrofuran, and sulfonamides, with high minimum inhibitory concentrations. It w...

Hot springs are tractable model systems in microbial ecology for investigating the interactions of photosynthetic microbial biofilms. This is because they occur across broad geographic scales, possess readily identified major abiotic variables, and are subject to minimal influence from metazoans. Despite this regional scale investigations are lacki...

Hot springs, with their well-characterized major abiotic variables and island-like habitats, are ideal systems for studying microbial biogeography. Photosynthetic biofilms are a major biological feature of hot springs but despite this large-scale studies are scarce, leaving critical questions about the drivers of spatial turnover unanswered. Here,...

Ferroptosis, characterized by iron-dependent cell death, has recently emerged as a critical defense mechanism against microbial infections. The present study aims to investigate the involvement of exosomes in the induction of ferroptosis and the inhibition of bacterial infection in crustaceans. Our findings provide compelling evidence for the pivot...

The complete mitogenomes of fruit flies Zeugodacus (Javadacus) calumniatus, Z. (Javadacus) heinrichi and Z. (Sinodacus) hochii have similar gene order and contain 37 genes and a non-coding region. They share an identical start codon for the respective protein-coding genes (PCGs), an identical TAA stop codon for 11 PCGs, TAG for cob , and an incompl...

A new next-generation probiotic, Christensenella minuta was first discovered in 2012 from healthy human stool and described under the phylum Firmicutes. C. minuta is a subdominant commensal bacterium with highly heritable properties that exhibits mutual interactions with other heritable microbiomes, and its relative abundance is positively correlat...

Background Streptococcus suis (S.suis) is a neglected zoonotic disease that imposes a significant economic burden on healthcare and society. To our knowledge, studies estimating the cost of illness associated with S.suis treatment are limited, and no study focuses on treatment costs and potential key drivers in Thailand. This study aimed to estimat...

Before the 2000s, New Zealand’s surveillance of antibiotic resistance in human pathogens detected less than nine annual cases of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (ESBL-E). In 2001, however, the Hawke’s Bay region experienced an increase in ESBL-E associated with clinical infections. Throughout 2001 and 2002, 95 iso...

Matrix metalloproteinase-12 (MMP12), or macrophage metalloelastase, plays important roles in extracellular matrix (ECM) component degradation. Recent reports show MMP12 has been implicated in the pathogenesis of periodontal diseases. To date, this review represents the latest comprehensive overview of MMP12 in various oral diseases, such as periodo...

Pteropine orthoreovirus (PRV), an emerging bat‐borne virus, has been linked to cases of acute respiratory infections (ARI) in humans. The prevalence, epidemiology and genomic diversity of PRV among ARI of unknown origin were studied. Among 632 urban outpatients tested negative for all known respiratory viruses, 2.2% were PRV‐positive. Patients main...

A novel strain, Streptomyces griseiviridis MUM 136JT was recovered from a mangrove forest soil in Malaysia. The Gram-positive bacterium forms strong yellow aerial mycelium and moderate yellow substrate mycelium on ISP 2 agar. A polyphasic approachwas used to determine the taxonomy status of strain MUM 136JT. The strain showed a spectrum of phylogen...

As feed accounts for a significant proportion of a farm’s expenditure, animal nutrition is one of the key profit determinants. Attributed to the size-dependent market value, enhancing shrimps' growth is essential to maximize profit. Despite not being the best option, antibiotics are often used as growth-promoting agents in farming. Although this tr...

As the world recovers from the COVID-19 pandemic, concern remains for future potential outbreaks because of the persisting effects of climate change, including the proliferation of infectious diseases. The frequent isolation of Vibrio parahaemolyticus in the surrounding environment is of concern as it can cause infections in marine animals and tran...

Migration is typically associated with risk and uncertainty at the population level, but little is known about its cost–benefit trade‐offs at the species level. Migratory insects in particular often exhibit strong demographic fluctuations due to local bottlenecks and outbreaks. Here, we use genomic data to investigate levels of heterozygosity and l...

Periodontal diseases are predisposing factors to the development of many systemic disorders, which is often initiated via leukocyte infiltration and vascular inflammation. These diseases could significantly affect human health and quality of life. Hence, it is vital to explore effective therapies to prevent disease progression. Periodontitis, which...

The continued circulation of SARS-CoV-2 virus in different parts of the world opens up the possibility for more virulent variants to evolve even as the coronavirus disease 2019 transitions from pandemic to endemic. Highly transmissible and virulent variants may seed new disruptive epidemic waves that can easily put the healthcare system under treme...

The plant pathogen Dickeya solani causes soft rot and blackleg diseases in several crops including Solanum tuberosum. Unveiling the patterns of its diversity contributes to understanding the emergence and virulence of this pathogen in potato agro-systems. In this study, we analyzed the genome of several D. solani strains exhibiting an atypically hi...

As an enduring hot topic in the field of innate immunity, apoptosis is widely considered as an effective approach to eliminate pathogenic microbes, and possesses crucial role during host-pathogen interactions. Recently, researchers have found that virus-containing host cells could transmit apoptotic signals to surrounding uninfected cells during in...

Boesenbergia rotunda (L.) Mansf. is a medically important ginger species of the family Zingiberaceae but its genomic information on molecular phylogeny and identification is scarce. In this work, the chloroplast genome of B. rotunda was sequenced, characterized and compared to the other Zingiberaceae species to provide chloroplast genetic resources...

The increasing prevalence of resistance in carbapenems is an escalating concern as carbapenems are reserved as last-line antibiotics. Although indiscriminate antibiotic usage is considered the primary cause for resistance development, increasing evidence revealed that inconsequential strains without any direct clinical relevance to carbapenem usage...

The chrysomelid beetles Podontia affinis and Silana farinosa are members of the subfamilies Galerucinae and Cassidinae, respectively. This study, based on 16S rRNA gene-targeted metagenomics sequencing, reports the core members and differential abundance of bacterial communities in the larvae and adult beetles of P. affinis and the adult S. farinos...

We report the draft genome sequence of the laboratory strain Staphylococcus aureus NCTC 6571-UB, a strain that was derived from S. aureus NCTC 6571. This strain was selected for sequencing in order to provide information on the genome dynamics and the acquired resistance genes for penicillin G, trimethoprim, and sulfamethoxazole resistance.

Chelatococcus daeguensis strain M38T9 is a thermotolerant bacterium isolated from a hot-spring in Malaysia. The draft genome of C. daeguensis strain M38T9 consists of 4,218,658 bp assembled into 50 scaffolds. The GC content of the genome is 67.91 %, and the sequencing coverage of 184×. There are 4,046 predicted genes, 3,962 protein-coding genes, an...

Background Streptococcus suis (S.suis) is a neglected zoonotic disease that imposes a significant economic burden on healthcare and society. To our knowledge, studies estimating the cost of illness associated with S.suis treatment are limited, and no study focuses on treatment costs and potential key drivers in Thailand. This study aimed to estimat...

We report the draft genome sequence and antibiotic susceptibility of Pseudomonas aeruginosa strain PAO1-UB, a subline of the common reference strain PAO1. This strain was sequenced in order to provide information on the genome dynamics of PAO1 sublines and their genes conferring resistance to multiple antibiotics.

Pseudomonas aeruginosa uses multiple protein regulators that work in tandem to control the production of a wide range of virulence factors and facilitate rapid adaptation to diverse environmental conditions. In this opportunistic pathogen, ToxR was known to positively regulate the production of the major virulence factor exotoxin A and now, through...

In this study, a novel bacterium designated F3b2T was isolated from the gut sample of weaver ant Oecophylla smaragdina and characterised. Strain F3b2T was a Gram-negative, aerobic, non-motile, ovoid-shaped bacterium and grows optimally at 28–30 °C. Its major respiratory quinone is ubiquinone 10 (Q-10) and the major fatty acids are C18:1ω7c, C19:0 c...

Migration is typically associated with risk and uncertainty at the population level, but little is known about its cost and benefit trade-offs at the species level. Migratory insects often exhibit strong demographic fluctuations due to local bottlenecks and outbreaks. Here, we use genomic data to investigate levels of heterozygosity and long-term p...

Pseudomonas aeruginosa uses multiple protein regulators that work in tandem to control the production of a wide range of virulence factors and facilitate rapid adaptation to diverse environmental conditions. In this opportunistic pathogen, ToxR was known to positively regulate the production of the major virulence factor exotoxin A and now, through...

Evidence has shown that gut microbiome plays a role in modulating the development of diseases beyond the gastrointestinal tract, including skin disorders such as psoriasis. The gut–skin axis refers to the bidirectional relationship between the gut microbiome and skin health. This is regulated through several mechanisms such as inflammatory mediator...

The human gut microbiota is vital for maintaining human health in terms of immune system homeostasis. Perturbations in the composition and function of microbiota have been associated with several autoimmune disorders, including myasthenia gravis (MG), a neuromuscular condition associated with varying weakness and rapid fatigue of the skeletal muscl...

There are many types of thermophilic prokaryotes, eukaryotes, and viruses that reside in heated environments such as hot springs and oil reservoirs. Comparative genomics and transcriptomics approaches, 16S rRNA marker sequencing (metataxonomy), shotgun metagenomes, and genomics help us gain a better understanding of thermophiles. An e-book with one...

Next Generation Sequencing technologies significantly impact the field of Antimicrobial Resistance (AMR) detection and monitoring, with immediate uses in diagnosis and risk assessment. For this application and in general, considerable challenges remain in demonstrating sufficient trust to act upon the meaningful information produced from raw data,...

SA is a phenolic acid plant hormone that plays an essential role in plant defenses against biotrophic and semibiotrophic pathogens. Substantial progress has been made in understanding the pivotal role of SA in plant immunity.

Background Despite the clinical burden attributable to rhinovirus (RV) infections, the RV transmission dynamics and the impact of interventions on viral transmission remain elusive. Methods A total of 3,935 nasopharyngeal specimens were examined, from which the VP4/VP2 gene was sequenced and genotyped. RV transmission clusters were reconstructed u...

The Antarctic continent is not exempted from anthropogenic contamination. Diesel spills on Antarctic soils occur frequently. There, extreme climate conditions and the scarce infrastructure, cause that few remediation strategies become feasible. Bioremediation has proven to be an effective approach for hydrocarbon-contaminated soils in Antarctica, a...

Purpose Pteropine orthoreovirus (PRV) is a bat-borne virus classified under the Reoviridae family. It is a recently emerging virus in Southeast Asia and has been associated with sporadic respiratory infections in humans. Despite its epidemic potential, PRV is often neglected during diagnosis for acute respiratory infection (ARI) and may be accounta...

Objective The naked mole rats (NMRs, Heterocephalus glaber ) are subterranean rodents that belong to the family Bathyergidae. They gained the attention of the scientific community for their exceptionally long lifespan of up to 30 years and have become an animal model of biomedical research on neurodegenerative diseases, aging and cancer. NMRs dig a...

The SKY hot spring is a unique site filled with a thick layer of plant litter. With the advancement of next-generation sequencing, it is now possible to mine many new biocatalyst sequences. In this study, we aimed to (i) identify the metataxonomic of prokaryotes and eukaryotes in microbial mats using 16S and 18S rRNA markers, (ii) and explore carbo...

Probiotics confer health benefits to aquatic animals, although the use of live probiotics could negatively impact the aquaculture environment. Thus, heat-killed probiotics are an alternative choice that could equally improve growth performance and disease resistance of farmed fish and shellfish. This review summarised current understanding of heat-...

As part of a screening programme for antibiotic-producing bacteria, a novel Actinomadura species was discovered from a soil sample collected in Santorini, Greece. Preliminary 16S rRNA gene sequence comparisons highlighted Actinomadura macra as the most similar characterised species. However, whole-genome sequencing revealed an average nucleotide id...

Insight in the quorum sensing-driven lifestyle of the non-pathogenic Agrobacterium 1 tumefaciens 6N2 and the interactions with the yeast Meyerozyma guilliermondii 2 3

The coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains a global threat with an ever-increasing death toll even after a year on. Hence, the rapid identification of infected individuals with diagnostic tests continues to be crucial in the on-going effort to combat the spread of COVID-1...

Agrobacterium tumefaciens is considered a prominent phytopathogen, though most isolates are nonpathogenic. Agrobacteria can inhabit plant tissues interacting with other microorganisms. Yeasts are likewise part of these communities. We analyzed the quorum sensing (QS) systems of A. tumefaciens strain 6N2, and its relevance for the interaction with t...

Agrobacterium tumefaciens is considered a prominent phytopathogen, though most isolates are nonpathogenic. Agrobacteria can inhabit plant tissues interacting with other microorganisms. Yeasts are likewise part of these communities. We analyzed the quorum sensing (QS) systems of A. tumefaciens strain 6N2, and its relevance for the interaction with t...

The worldwide battle against the SARS-CoV-2 virus rages on, with millions infected and many innocent lives lost. The causative organism, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a beta coronavirus that belongs to the Coronaviridae family. Many clinically significant variants have emerged, as the virus’s genome is prone to va...

Background The genus Streptomyces is well-known for the production of numerous bioactive compounds with interesting chemical scaffolds. Streptomyces pluripotens MUSC 135T was isolated from a mangrove forest in Malaysia during a screening program for bioactive actinobacteria. The crude fermentative extract of MUSC 135T was shown to inhibit the growt...

It is well known that exosomes could serve as anti-microbial immune factors in animals. However, despite growing evidences have shown that the homeostasis of the hemolymph microbiota was vital for immune regulation in crustaceans, the relationship between exosomes and hemolymph microbiota homeostasis during pathogenic bacteria infection has not bee...

Background Tephritid fruit flies of the genus Dacus are members of the tribe Dacini, subfamily Dacinae. There are some 274 species worldwide, distributed in Africa and the Asia-Pacific. To date, only five complete mitochondrial genomes (mitogenomes) of Dacus fruit flies have been published and are available in the GenBank. Methods and results In v...

Bacterial vaginosis (BV) has been reported in one-third of women worldwide at different life stages, due to the complex balance in the ecology of the vaginal microbiota. It is a common cause of abnormal vaginal discharge and is associated with other health issues. Since the first description of anaerobic microbes associated with BV like Gardnerella...

Actinobacteria constitute prolific sources of novel and vital bioactive metabolites for pharmaceutical utilization. In recent years, research has focused on exploring actinobacteria that thrive in extreme conditions to unearth their beneficial bioactive compounds for natural product drug discovery. Natural products have a significant role in resolv...

Background: Chronic kidney disease (CKD)-associated pruritus (CKD-aP) contributes to poor quality of life, including reduced sleep quality and poor sleep quality is a source of patient stress and is linked to lower health-related quality of life. This study aimed to investigate the effectiveness of zolpidem 10 mg and acupressure therapy on foot ac...

Cellulose nanofibers (CNF) isolated from plant biomass have attracted considerable interests in polymer engineering. The limitations associated with CNF-based nanocomposites are often linked to the time-consuming preparation methods and lack of desired surface functionalities. Herein, we demonstrate the feasibility of preparing a multifunctional CN...

Acting like mini-factories, microorganisms are a valuable source of naturalbioactive compounds of unique chemical structures. Peribacillus sp. MUM 13 was recoveredfrom the mangrove forest in Malaysia during a screening program for bioactive microbes.Whole genome analysis revealed that the genome size of MUM 13 as 4,649,225 bp (with G+ C content of...

Spiders of the genera Nephila and Trichonephila are large orb-weaving spiders. In view of the lack of study on the mitogenome of these genera, and the conflicting systematic status, we sequenced (by next generation sequencing) and annotated the complete mitogenomes of N. pilipes, T. antipodiana and T. vitiana (previously N. vitiana) to determine th...

The field of probiotic has been exponentially expanding over the recent decades with a more therapeutic-centered research. Probiotics mediated microbiota modulation within the microbiota–gut–brain axis (MGBA) have been proven to be beneficial in various health domains through pre-clinical and clinical studies. In the context of mental health, altho...

Background Coxsackievirus A21 (CVA21), a member of Enterovirus C from the Picornaviridae family, has been associated with respiratory illnesses in humans. Methods A molecular epidemiological investigation of CVA21 was conducted among patients presenting with acute upper respiratory illnesses in the ambulatory settings between 2012 and 2014 in Kual...

Since the 1950s, antibiotics have been used in the field of animal husbandry for growth promotion, therapy and disease prophylaxis. It is estimated that up to 80% of the antibiotics produced by the pharmaceutical industries are used in food production. Most of the antibiotics are used as feed additives at sub-therapeutic levels to promote growth. H...

The contribution of streptomycetes to human health is undeniably important and significant, given that these filamentous microbes can produce interesting compounds that can be used to cure deadly infections and even cancer. Isolated from the east coast of Peninsular Malaysia, Streptomyces sp. MUSC 14 has shown significant antioxidant capacity. The...

Simple Summary This review highlights the medicinal benefits of a natural remedy, the Carica papaya extracts and its phytochemicals. In this review, the potential of Carica papaya against various conditions, including cancer, inflammation, aging, healing of the skin, and lifelong diseases has been summarized and discussed. In short, more research a...

People around the world ushered in the new year 2021 with a fear of COVID-19, as family members have lost their loved ones to the disease. Millions of people have been infected, and the livelihood of many has been jeopardized due to the pandemic. Pharmaceutical companies are racing against time to develop an effective vaccine to protect against COV...

The global pandemic of the coronavirus disease 2019 is a known consequence of infection of severe respiratory syndrome coronavirus-2 (SARS-CoV-2). It has affected nations worldwide with soaring number of cases daily. Symptoms such as fever, cough, and shortness of breath, diarrhea, nausea and vomiting are commonly presented in COVID-19 patients. Th...

Next Generation Sequencing technologies significantly impact the field of Antimicrobial Resistance (AMR) detection and monitoring, with immediate uses in diagnosis and risk assessment. For this application and in general, considerable challenges remain in demonstrating sufficient trust to act upon the meaningful information produced from raw data,...

Post-transcriptional regulation is an important step in the control of bacterial gene expression in response to environmental and cellular signals. Pseudomonas putida KT2440 harbors three known members of the CsrA/RsmA family of post-transcriptional regulators: RsmA, RsmE and RsmI. We have carried out a global analysis to identify RNA sequences bou...

The bacterium Oecophyllibacter saccharovorans of family Acetobacteraceae is a symbiont of weaver ant Oecophylla smaragdina. In our previous study, we published the finding of novel O. saccharovorans strains Ha5T, Ta1 and Jb2 (Chua et al. 2020) but their plasmid sequences have not been reported before. Here, we demonstrate for the first time that th...

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) began as a cluster of pneumonia cases in Wuhan, China before spreading to over 200 countries and territories on six continents in less than six months. Despite rigorous global containment and quarantine efforts to limit the transmission of...