Publications by authors named "Sheila Nathan"

83 Publications

Metabolomic characterization of colorectal cancer cell lines highlighting stage-specific alterations during cancer progression.

Bioimpacts 2021 10;11(2):147-156. Epub 2020 Jun 10.

Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Universiti Teknologi MARA, Campus Sungai Buloh, 47000 Sungai Buloh, Selangor, Malaysia.

Metabolomic studies on various colorectal cancer (CRC) cell lines have improved our understanding of the biochemical events underlying the disease. However, the metabolic profile dynamics associated with different stages of CRC progression is still lacking. Such information can provide further insights into the pathophysiology and progression of the disease that will prove useful in identifying specific targets for drug designing and therapeutics. Thus, our study aims to characterize the metabolite profiles in the established cell lines corresponding to different stages of CRC. Metabolite profiling of normal colon cell lines (CCD 841 CoN) and CRC cell lines corresponding to different stages, i.e., SW 1116 (stage A), HT 29 and SW 480 (stage B), HCT 15 and DLD-1 (stage C), and HCT 116 (stage D), was carried out using liquid chromatography-mass spectrometry (LC-MS). Mass Profiler Professional and Metaboanalyst 4.0 software were used for statistical and pathway analysis. METLIN database was used for the identification of metabolites. We identified 72 differential metabolites compared between CRC cell lines of all the stages and normal colon cells. Principle component analysis and partial least squares discriminant analysis score plot were used to segregate normal and CRC cells, as well as CRC cells in different stages of the disease. Variable importance in projection score identified unique differential metabolites in CRC cells of the different stages. We identified 7 differential metabolites unique to stage A, 3 in stage B, 5 in stage C, and 5 in stage D. This study highlights the differential metabolite profiling in CRC cell lines corresponding to different stages. The identification of the differential metabolites in CRC cells at individual stages will lead to a better understanding of the pathophysiology of CRC development and progression and, hence, its application in treatment strategies.
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http://dx.doi.org/10.34172/bi.2021.22DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8022234PMC
June 2020

Expression of Ascaris lumbricoides putative virulence-associated genes when infecting a human host.

Parasit Vectors 2021 Mar 23;14(1):176. Epub 2021 Mar 23.

Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor, Malaysia.

Background: Ascaris lumbricoides is the most common causative agent of soil-transmitted helminth infections worldwide, with an estimated 450 million people infected with this nematode globally. It is suggested that helminths are capable of evading and manipulating the host immune system through the release of a spectrum of worm proteins which underpins their long-term survival in the host. We hypothesise that the worm overexpresses these proteins when infecting adults compared to children to cirvumvent the more robust defence mechanisms of adults. However, little is known about the parasite's genes and encoded proteins involved during A. lumbricoides infection. Hence, this study was conducted to assess the expression profile of putative virulence-associated genes during an active infection of adults and children.

Methods: In this study, quantitative PCR was performed to evaluate the expression profile of putative virulence-associated genes in A. lumbricoides isolated from infected children and adults. The study was initiated by collecting adult worms expelled from adults and children following anthelminthic treatment. High-quality RNA was successfully extracted from each of six adult worms expelled by three adults and three children, respectively. Eleven putative homologues of helminth virulence-associated genes reported in previous studies were selected, primers were designed and specific amplicons of A. lumbricoides genes were noted. The expression profiles of these putative virulence-associated genes in A. lumbricoides from infected adults were compared to those in A. lumbricoides from infected children.

Results: The putative virulence-associated genes VENOM, CADHERIN and PEBP were significantly upregulated at 166-fold, 13-fold and fivefold, respectively, in adults compared to children. Conversely, the transcription of ABA-1 (fourfold), CATH-L (threefold) and INTEGRIN (twofold) was significantly suppressed in A. lumbricoides from infected adults.

Conclusions: On the basis of the expression profile of the putative virulence-associated genes, we propose that the encoded proteins have potential roles in evasion mechanisms, which could guide the development of therapeutic interventions.
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http://dx.doi.org/10.1186/s13071-021-04680-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7985925PMC
March 2021

The structure of a major surface antigen SAG19 from Eimeria tenella unifies the Eimeria SAG family.

Commun Biol 2021 Mar 19;4(1):376. Epub 2021 Mar 19.

Department of Molecular Biology and Biotechnology, Krebs Institute for Biomolecular Research, The University of Sheffield, Sheffield, UK.

In infections by apicomplexan parasites including Plasmodium, Toxoplasma gondii, and Eimeria, host interactions are mediated by proteins including families of membrane-anchored cysteine-rich surface antigens (SAGs) and SAG-related sequences (SRS). Eimeria tenella causes caecal coccidiosis in chickens and has a SAG family with over 80 members making up 1% of the proteome. We have solved the structure of a representative E. tenella SAG, EtSAG19, revealing that, despite a low level of sequence similarity, the entire Eimeria SAG family is unified by its three-layer αβα fold which is related to that of the CAP superfamily. Furthermore, sequence comparisons show that the Eimeria SAG fold is conserved in surface antigens of the human coccidial parasite Cyclospora cayetanensis but this fold is unrelated to that of the SAGs/SRS proteins expressed in other apicomplexans including Plasmodium species and the cyst-forming coccidia Toxoplasma gondii, Neospora caninum and Besnoitia besnoiti. However, despite having very different structures, Consurf analysis showed that Eimeria SAG and Toxoplasma SRS families each exhibit marked hotspots of sequence hypervariability that map to their surfaces distal to the membrane anchor. This suggests that the primary and convergent purpose of the different structures is to provide a platform onto which sequence variability can be imposed.
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http://dx.doi.org/10.1038/s42003-021-01904-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7979774PMC
March 2021

Whole-genome comparative analysis of Malaysian clinical isolates.

Microb Genom 2021 02;7(2)

Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.

, a soil-dwelling Gram-negative bacterium, is the causative agent of the endemic tropical disease melioidosis. Clinical manifestations of infection range from acute or chronic localized infection in a single organ to fulminant septicaemia in multiple organs. The diverse clinical manifestations are attributed to various factors, including the genome plasticity across strains. We previously characterized strains isolated in Malaysia and noted different levels of virulence in model hosts. We hypothesized that the difference in virulence might be a result of variance at the genome level. In this study, we sequenced and assembled four Malaysian clinical isolates, UKMR15, UKMPMC2000, UKMD286 and UKMH10. Phylogenomic analysis showed that Malaysian subclades emerged from the Asian subclade, suggesting that the Malaysian strains originated from the Asian region. Interestingly, the low-virulence strain, UKMH10, was the most distantly related compared to the other Malaysian isolates. Genomic island (GI) prediction analysis identified a new island of 23 kb, GI9c, which is present in and , but not . Genes encoding known virulence factors were present across all four genomes, but comparative analysis of the total gene content across the Malaysian strains identified 104 genes that are absent in UKMH10. We propose that these genes may encode novel virulence factors, which may explain the reduced virulence of this strain. Further investigation on the identity and role of these 104 proteins may aid in understanding pathogenicity to guide the design of new therapeutics for treating melioidosis.
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http://dx.doi.org/10.1099/mgen.0.000527DOI Listing
February 2021

Immunogenicity and protection efficacy of enhanced fitness recombinant Typhi monovalent and bivalent vaccine strains against acute toxoplasmosis.

Pathog Glob Health 2021 Feb 1:1-13. Epub 2021 Feb 1.

Division of Biomedical Sciences, School of Pharmacy, the University of Nottingham Malaysia Campus , Semenyih, Selangor, Malaysia.

The proficiency of Typhi to induce cell-mediated immunity has allowed its exploitation as a live vector against the obligate intracellular protozoan . vaccine research is of great medical value due to the lack of a suitable toxoplasmosis vaccine. In the present work, we integrated antigen into a growth-dependent chromosome locus of . Typhi CVD910 strain to form recombinant . Typhi monovalent CVD910-SAG1 expressed SAG1 antigen and monovalent CVD910-GRA2 expressed GRA2 antigen. Furthermore, a low-copy stabilized recombinant plasmid encoding SAG1 antigen was transformed into CVD910-GRA2 to form bivalent CVD910-GS strain. An osmolarity-regulated promoter was also incorporated to control the gene transcription, whereas clyA export protein was included to translocate the antigen out of the cytoplasm. Both CVD910-GRA2 and CVD910-GS displayed healthy growth fitness and readily expressed the encoded antigens. When administered , CVD910-GS successfully induced both humoral and cellular immunity in the immunized BALB/c mice, and extended mice survival against virulent . In particular, the mice immunized with bivalent CVD910-GS presented the highest titers of IgG, percentages of CD4 T, CD8 T, B cells and memory T cells, and total IgG memory B cells as compared to the CVD910-GRA2 and control strains. The CVD910-GS group also generated mixed Th1/Th2 cytokine profile with secretions of IFN-ɣ, IL-2 and IL-10. This study demonstrated the importance of enhancing live vector fitness to sustain heterologous antigen expression for eliciting robust immune responses and providing effective protection against pathogen.
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http://dx.doi.org/10.1080/20477724.2021.1881369DOI Listing
February 2021

Global metabolomics profiling of colorectal cancer in Malaysian patients.

Bioimpacts 2021 24;11(1):33-43. Epub 2020 Mar 24.

Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Universiti Teknologi MARA, Cawangan Selangor, Kampus Sungai Buloh, 47000 Sungai Buloh, Selangor, Malaysia.

The serum metabolomics approach has been used to identify metabolite biomarkers that can diagnose colorectal cancer (CRC) accurately and specifically. However, the biomarkers identified differ between studies suggesting that more studies need to be performed to understand the influence of genetic and environmental factors. Therefore, this study aimed to identify biomarkers and affected metabolic pathways in Malaysian CRC patients. Serum from 50 healthy controls and 50 CRC patients were collected at UKM Medical Centre. The samples were deproteinized with acetonitrile and untargeted metabolomics profile determined using liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOFMS, Agilent USA). The data were analysed using Mass Profiler Professional (Agilent, USA) software. The panel of biomarkers determined were then used to identify CRC from a new set of 20 matched samples. Eleven differential metabolites were identified whose levels were significantly different between CRC patients compared to normal controls. Based on the analysis of the area under the curve, 7 of these metabolites showed high sensitivity and specificity as biomarkers. The use of the 11 metabolites on a new set of samples was able to differentiate CRC from normal samples with 80% accuracy. These metabolites were hypoxanthine, acetylcarnitine, xanthine, uric acid, tyrosine, methionine, lysoPC, lysoPE, citric acid, 5-oxoproline, and pipercolic acid. The data also showed that the most perturbed pathways in CRC were purine, catecholamine, and amino acid metabolisms. Serum metabolomics profiling can be used to identify distinguishing biomarkers for CRC as well as to further our knowledge of its pathophysiological mechanisms.
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http://dx.doi.org/10.34172/bi.2021.05DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7803921PMC
March 2020

Multi locus sequence typing of clinical Burkholderia pseudomallei isolates from Malaysia.

PLoS Negl Trop Dis 2020 12 28;14(12):e0008979. Epub 2020 Dec 28.

Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.

Background: Melioidosis is a neglected tropical disease with rising global public health and clinical importance. Melioidosis is endemic in Southeast Asia and Northern Australia and is of increasing concern in Malaysia. Despite a number of reported studies from Malaysia, these reports are limited to certain parts of the country and do not provide a cohesive link between epidemiology of melioidosis cases and the nation-wide distribution of the causative agent Burkholderia pseudomallei.

Methodology/principle Findings: Here we report on the distribution of B. pseudomallei sequence types (STs) in Malaysia and how the STs are related to STs globally. We obtained 84 culture-confirmed B. pseudomallei from confirmed septicaemic melioidosis patients from all over Malaysia. Prior to performing Multi Locus Sequence Typing, the isolates were subjected to antimicrobial susceptibility testing and detection of the YLF/BTFC genes and BimA allele. Up to 90.5% of the isolates were sensitive to all antimicrobials tested while resistance was observed for antimicrobials typically administered during the eradication stage of treatment. YLF gene cluster and bimABp allele variant were detected in all the isolates. The epidemiological distribution patterns of the Malaysian B. pseudomallei isolates were analysed in silico using phylogenetic tools and compared to Southeast Asian and world-wide isolates. Genotyping of the 84 Malaysian B. pseudomallei isolates revealed 29 different STs of which 6 (7.1%) were novel. ST50 was identified as the group founder followed by subgroup founders ST376, ST211 and ST84. A low-level diversity is noted for the B. pseudomallei isolates described in this study while phylogenetic analysis associated the Malaysian STs to Southeast Asian isolates especially isolates from Thailand. Further analysis also showed a strong association that implicates agriculture and domestication activities as high-risk routes of infection.

Conclusions/significance: In conclusion, MLST analysis of B. pseudomallei clinical isolates from all states in Malaysia revealed low diversity and a close association to Southeast Asian isolates.
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http://dx.doi.org/10.1371/journal.pntd.0008979DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7793247PMC
December 2020

Advantages and Limitations of 16S rRNA Next-Generation Sequencing for Pathogen Identification in the Diagnostic Microbiology Laboratory: Perspectives from a Middle-Income Country.

Diagnostics (Basel) 2020 Oct 14;10(10). Epub 2020 Oct 14.

BioEasy Sdn. Bhd., Selangor 40170, Malaysia.

Bacterial culture and biochemical testing (CBtest) have been the cornerstone of pathogen identification in the diagnostic microbiology laboratory. With the advent of Sanger sequencing and later, next-generation sequencing, 16S rRNA next-generation sequencing (16SNGS) has been proposed to be a plausible platform for this purpose. Nevertheless, usage of the 16SNGS platform has both advantages and limitations. In addition, transition from the traditional methods of CBtest to 16SNGS requires procurement of costly equipment, timely and sustainable maintenance of these platforms, specific facility infrastructure and technical expertise. All these factors pose a challenge for middle-income countries, more so for countries in the lower middle-income range. In this review, we describe the basis for CBtest and 16SNGS, and discuss the limitations, challenges, advantages and future potential of using 16SNGS for bacterial pathogen identification in diagnostic microbiology laboratories of middle-income countries.
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http://dx.doi.org/10.3390/diagnostics10100816DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7602188PMC
October 2020

Burkholderia pseudomallei pathogenesis and survival in different niches.

Biochem Soc Trans 2020 04;48(2):569-579

Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan, Malaysia.

Burkholderia pseudomallei (Bp) is the causative agent of melioidosis, a disease of the tropics with high clinical mortality rates. To date, no vaccines are approved for melioidosis and current treatment relies on antibiotics. Conversely, common misdiagnosis and high pathogenicity of Bp hamper efforts to fight melioidosis. This bacterium can be isolated from a wide range of niches such as waterlogged fields, stagnant water bodies, salt water bodies and from human and animal clinical specimens. Although extensive studies have been undertaken to elucidate pathogenesis mechanisms of Bp, little is known about how a harmless soil bacterium adapts to different environmental conditions, in particular, the shift to a human host to become a highly virulent pathogen. The bacterium has a large genome encoding an armory of factors that assist the pathogen in surviving under stressful conditions and assuming its role as a deadly intracellular pathogen. This review presents an overview of what is currently known about how the pathogen adapts to different environments. With in-depth understanding of Bp adaptation and survival, more effective therapies for melioidosis can be developed by targeting related genes or proteins that play a major role in the bacteria's survival.
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http://dx.doi.org/10.1042/BST20190836DOI Listing
April 2020

Vaccination challenges and strategies against long-lived Toxoplasma gondii.

Vaccine 2019 07 8;37(30):3989-4000. Epub 2019 Jun 8.

Division of Biomedical Sciences, School of Pharmacy, The University of Nottingham Malaysia Campus, 43500 Semenyih, Selangor, Malaysia. Electronic address:

Since the discovery of Toxoplasma gondii in 1908, it is estimated that one-third of the global population has been exposed to this ubiquitous intracellular protozoan. The complex life cycle of T. gondii has enabled itself to overcome stress and transmit easily within a broad host range thus achieving a high seroprevalence worldwide. To date, toxoplasmosis remains one of the most prevalent HIV-associated opportunistic central nervous system infections. This review presents a comprehensive overview of different vaccination approaches ranging from traditional inactivated whole-T. gondii vaccines to the popular DNA vaccines. Extensive discussions are made to highlight the challenges in constructing these vaccines, selecting adjuvants as well as delivery methods, immunisation approaches and developing study models. Herein we also deliberate over the latest and promising enhancement strategies that can address the limitations in developing an effective T. gondii prophylactic vaccine.
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http://dx.doi.org/10.1016/j.vaccine.2019.05.083DOI Listing
July 2019

Recent advancements in high-level synthesis of the promising clinical drug, prodigiosin.

Appl Microbiol Biotechnol 2019 Feb 12;103(4):1667-1680. Epub 2019 Jan 12.

School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor, Malaysia.

Prodigiosin, a red linear tripyrrole pigment and a member of the prodiginine family, is normally secreted by the human pathogen Serratia marcescens as a secondary metabolite. Studies on prodigiosin have received renewed attention as a result of reported immunosuppressive, antimicrobial and anticancer properties. High-level synthesis of prodigiosin and the bioengineering of strains to synthesise useful prodiginine derivatives have also been a subject of investigation. To exploit the potential use of prodigiosin as a clinical drug targeting bacteria or as a dye for textiles, high-level synthesis of prodigiosin is a prerequisite. This review presents an overview on the biosynthesis of prodigiosin from its natural host Serratia marcescens and through recombinant approaches as well as highlighting the beneficial properties of prodigiosin. We also discuss the prospect of adopting a synthetic biology approach for safe and cost-effective production of prodigiosin in a more industrially compliant surrogate host.
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http://dx.doi.org/10.1007/s00253-018-09611-zDOI Listing
February 2019

Molecular characterization of Trichuris species isolated from humans, dogs and cats in a rural community in Peninsular Malaysia.

Acta Trop 2019 Feb 27;190:269-272. Epub 2018 Nov 27.

Department of Parasitology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia. Electronic address:

Trichuris trichiura (whipworm) are soil-transmitted helminths (STHs) that causing trichuriasis in human. Trichuris vulpis, a canine whipworm has also been reported occasionally in humans. However, an overlapping dimension in the morphology and due to limited external characters between both species may lead to the potential for misidentification. Although there has been an extensive study on the distribution of whipworm in both human and animal hosts, little is known about the molecular epidemiology of Trichuris species in both hosts. To investigate to characterize the whipworm species and to determine the genetic relationship between species infecting both humans and animals, we sequenced the small subunit ribosomal RNA (SSU rRNA) regions of Trichuris egg isolated from humans, dogs and cats in a rural community in Malaysia. A total of 524 fresh fecal samples were collected from humans and animals. The overall prevalence of Trichuris was 59.9% as determined by microscopy examination. The molecular analysis showed that 98.7% were identified as T. trichiura in the human fecal sample. Interestingly, 1.3% were identified as T. vulpis. As for animal fecal sample, 56.8% and 43.2% were identified as T. trichiura and T. vulpis, respectively. Phylogenetic and sequence analysis demonstrated that T. trichiura isolates were genetically distinct from T. vulpis isolates from both hosts. This finding implies that companion animals can be a reservoir and mechanical transmitter for T. trichiura infection in human and also highlighting the possible zoonotic potential of T. vulpis. This finding may also suggest that cross-transmission between humans and animal hosts in sympatric setting may be a source of infection in both hosts. More studies are needed to better understand the transmission dynamic and public health significance of Trichuris infection in both hosts.
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http://dx.doi.org/10.1016/j.actatropica.2018.11.026DOI Listing
February 2019

Melioidosis in Malaysia: Incidence, Clinical Challenges, and Advances in Understanding Pathogenesis.

Trop Med Infect Dis 2018 Feb 27;3(1). Epub 2018 Feb 27.

Department of Internal Medicine, Kulliyyah of Medicine, International Islamic University Malaysia, Kuantan 25200, Malaysia.

Malaysia is an endemic hot spot for melioidosis; however, a comprehensive picture of the burden of disease, clinical presentations, and challenges faced in diagnosis and treatment of melioidosis is not available. This review provides a nonexhaustive overview of epidemiological data, clinical studies, risk factors, and mortality rates from available literature and case reports. Clinical patterns of melioidosis are generally consistent with those from South and Southeast Asia in terms of common primary presentations with diabetes as a major risk factor. Early diagnosis and appropriate management of Malaysian patients is a key limiting factor, which needs to be addressed to reduce serious complications and high mortality and recurrence rates. Promoting awareness among the local healthcare personnel is crucial to improving diagnostics and early treatment, as well as educating the Malaysian public on disease symptoms and risk factors. A further matter of urgency is the need to make this a notifiable disease and the establishment of a national melioidosis registry. We also highlight local studies on the causative agent, , with regards to bacteriology and identification of virulence factors as well as findings from host⁻pathogen interaction studies. Collectively, these studies have uncovered new correlations and insights for further understanding of the disease.
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http://dx.doi.org/10.3390/tropicalmed3010025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6136604PMC
February 2018

Genetic Determinants Associated With Survival of in the Model.

Front Microbiol 2018 29;9:1118. Epub 2018 May 29.

School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Malaysia.

A infection usually leads to reduced survival and fatal syndrome in cystic fibrosis patients. The identification of essential genes for survival is key to designing new anti-infectives therapies. We used the Transposon-Directed Insertion Sequencing (TraDIS) approach to identify genes required for survival in the model infection host, . A J2315 transposon pool of ∼500,000 mutants was used to infect . We identified 178 genes as crucial for survival in the infected nematode. The majority of these genes code for proteins of unknown function, many of which are encoded by the genomic island BcenGI13, while other gene products are involved in nutrient acquisition, general stress responses and LPS -antigen biosynthesis. Deletion of the glycosyltransferase gene and a histone-like nucleoid structuring (H-NS) protein-encoding gene (BCAL0154) reduced bacterial accumulation and attenuated virulence in . Further analysis using quantitative RT-PCR indicated that BCAL0154 modulates pathogenesis via transcriptional regulation of motility-associated genes including , and . This screen has successfully identified genes required for survival within the host-associated environment, many of which are potential targets for developing new antimicrobials.
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http://dx.doi.org/10.3389/fmicb.2018.01118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5987112PMC
May 2018

Suppression of Staphylococcus aureus biofilm formation and virulence by a benzimidazole derivative, UM-C162.

Sci Rep 2018 02 9;8(1):2758. Epub 2018 Feb 9.

School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi Selangor, Malaysia.

Staphylococcus aureus is a major cause of nosocomial infections and secretes a diverse spectrum of virulence determinants as well as forms biofilm. The emergence of antibiotic-resistant S. aureus highlights the need for alternative forms of therapeutics other than conventional antibiotics. One route to meet this need is screening small molecule derivatives for potential anti-infective activity. Using a previously optimized C. elegans - S. aureus small molecule screen, we identified a benzimidazole derivative, UM-C162, which rescued nematodes from a S. aureus infection. UM-C162 prevented the formation of biofilm in a dose-dependent manner without interfering with bacterial viability. To examine the effect of UM-C162 on the expression of S. aureus virulence genes, a genome-wide transcriptome analysis was performed on UM-C162-treated pathogen. Our data indicated that the genes associated with biofilm formation, particularly those involved in bacterial attachment, were suppressed in UM-C162-treated bacteria. Additionally, a set of genes encoding vital S. aureus virulence factors were also down-regulated in the presence of UM-C162. Further biochemical analysis validated that UM-C162-mediated disruption of S. aureus hemolysins, proteases and clumping factors production. Collectively, our findings propose that UM-C162 is a promising compound that can be further developed as an anti-virulence agent to control S. aureus infections.
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http://dx.doi.org/10.1038/s41598-018-21141-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5807447PMC
February 2018

Identification of sRNA mediated responses to nutrient depletion in Burkholderia pseudomallei.

Sci Rep 2017 12 7;7(1):17173. Epub 2017 Dec 7.

School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia.

The Burkholderia genus includes many species that are known to survive in diverse environmental conditions including low nutrient environments. One species, Burkholderia pseudomallei is a versatile pathogen that can survive in a wide range of hosts and environmental conditions. In this study, we investigated how a nutrient depleted growth environment evokes sRNA mediated responses by B. pseudomallei. Computationally predicted B. pseudomallei D286 sRNAs were mapped to RNA-sequencing data for cultures grown under two conditions: (1) BHIB as a nutrient rich media reference environment and (2) M9 media as a nutrient depleted stress environment. The sRNAs were further selected to identify potentially cis-encoded systems by investigating their possible interactions with their flanking genes. The mappings of predicted sRNA genes and interactions analysis to their flanking genes identified 12 sRNA candidates that may possibly have cis-acting regulatory roles that are associated to a nutrient depleted growth environment. Our approach can be used for identifying novel sRNA genes and their possible role as cis-mediated regulatory systems.
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http://dx.doi.org/10.1038/s41598-017-17356-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5719362PMC
December 2017

Effects of simulated microgravity on gene expression and biological phenotypes of a single generation Caenorhabditis elegans cultured on 2 different media.

Life Sci Space Res (Amst) 2017 Nov 24;15:11-17. Epub 2017 Jun 24.

UKM Medical Molecular Biology Institute, Universiti Kebangsaan Malaysia, Malaysia. Electronic address:

Studies of multigenerational Caenorhabditis elegans exposed to long-term spaceflight have revealed expression changes of genes involved in longevity, DNA repair, and locomotion. However, results from spaceflight experiments are difficult to reproduce as space missions are costly and opportunities are rather limited for researchers. In addition, multigenerational cultures of C. elegans used in previous studies contribute to mixture of gene expression profiles from both larvae and adult worms, which were recently reported to be different. Usage of different culture media during microgravity simulation experiments might also give rise to differences in the gene expression and biological phenotypes of the worms. In this study, we investigated the effects of simulated microgravity on the gene expression and biological phenotype profiles of a single generation of C. elegans worms cultured on 2 different culture media. A desktop Random Positioning Machine (RPM) was used to simulate microgravity on the worms for approximately 52 to 54 h. Gene expression profile was analysed using the Affymetrix GeneChip® C. elegans 1.0 ST Array. Only one gene (R01H2.2) was found to be downregulated in nematode growth medium (NGM)-cultured worms exposed to simulated microgravity. On the other hand, eight genes were differentially expressed for C. elegans Maintenance Medium (CeMM)-cultured worms in microgravity; six were upregulated, while two were downregulated. Five of the upregulated genes (C07E3.15, C34H3.21, C32D5.16, F35H8.9 and C34F11.17) encode non-coding RNAs. In terms of biological phenotype, we observed that microgravity-simulated worms experienced minimal changes in terms of lifespan, locomotion and reproductive capabilities in comparison with the ground controls. Taking it all together, simulated microgravity on a single generation of C. elegans did not confer major changes to their gene expression and biological phenotype. Nevertheless, exposure of the worms to microgravity lead to higher expression of non-coding RNA genes, which may play an epigenetic role in the worms during longer terms of microgravity exposure.
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http://dx.doi.org/10.1016/j.lssr.2017.06.002DOI Listing
November 2017

Beyond Traditional Antimicrobials: A Model for Discovery of Novel Anti-infectives.

Front Microbiol 2016 2;7:1956. Epub 2016 Dec 2.

School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia Bangi, Malaysia.

The spread of antibiotic resistance amongst bacterial pathogens has led to an urgent need for new antimicrobial compounds with novel modes of action that minimize the potential for drug resistance. To date, the development of new antimicrobial drugs is still lagging far behind the rising demand, partly owing to the absence of an effective screening platform. Over the last decade, the nematode has been incorporated as a whole animal screening platform for antimicrobials. This development is taking advantage of the vast knowledge on worm physiology and how it interacts with bacterial and fungal pathogens. In addition to allowing for selection of compounds with promising anti-microbial properties, the whole animal screening system has also permitted the discovery of novel compounds targeting infection processes that only manifest during the course of pathogen infection of the host. Another advantage of using in the search for new antimicrobials is that the worm itself is a source of potential antimicrobial effectors which constitute part of its immune defense response to thwart infections. This has led to the evaluation of effector molecules, particularly antimicrobial proteins and peptides (APPs), as candidates for further development as therapeutic agents. In this review, we provide an overview on use of the model for identification of novel anti-infectives. We highlight some highly potential lead compounds obtained from -based screens, particularly those that target bacterial virulence or host defense to eradicate infections, a mechanism distinct from the action of conventional antibiotics. We also review the prospect of using APPs as an antimicrobial strategy to treat infections.
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http://dx.doi.org/10.3389/fmicb.2016.01956DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5133244PMC
December 2016

Nematode Peptides with Host-Directed Anti-inflammatory Activity Rescue Caenorhabditis elegans from a Burkholderia pseudomallei Infection.

Front Microbiol 2016 12;7:1436. Epub 2016 Sep 12.

School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan MalaysiaBangi, Malaysia; Malaysia Genome InstituteKajang, Malaysia.

Burkholderia pseudomallei, the causative agent of melioidosis, is among a growing number of bacterial pathogens that are increasingly antibiotic resistant. Antimicrobial peptides (AMPs) have been investigated as an alternative approach to treat microbial infections, as generally, there is a lower likelihood that a pathogen will develop resistance to AMPs. In this study, 36 candidate Caenorhabditis elegans genes that encode secreted peptides of <150 amino acids and previously shown to be overexpressed during infection by B. pseudomallei were identified from the expression profile of infected nematodes. RNA interference (RNAi)-based knockdown of 12/34 peptide-encoding genes resulted in enhanced nematode susceptibility to B. pseudomallei without affecting worm fitness. A microdilution test demonstrated that two peptides, NLP-31 and Y43C5A.3, exhibited anti-B. pseudomallei activity in a dose dependent manner on different pathogens. Time kill analysis proposed that these peptides were bacteriostatic against B. pseudomallei at concentrations up to 8× MIC90. The SYTOX green assay demonstrated that NLP-31 and Y43C5A.3 did not disrupt the B. pseudomallei membrane. Instead, gel retardation assays revealed that both peptides were able to bind to DNA and interfere with bacterial viability. In parallel, microscopic examination showed induction of cellular filamentation, a hallmark of DNA synthesis inhibition, of NLP-31 and Y43C5A.3 treated cells. In addition, the peptides also regulated the expression of inflammatory cytokines in B. pseudomallei infected macrophage cells. Collectively, these findings demonstrate the potential of NLP-31 and Y43C5A.3 as anti-B. pseudomallei peptides based on their function as immune modulators.
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http://dx.doi.org/10.3389/fmicb.2016.01436DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5019075PMC
September 2016

Candidate Essential Genes in Burkholderia cenocepacia J2315 Identified by Genome-Wide TraDIS.

Front Microbiol 2016 22;7:1288. Epub 2016 Aug 22.

Faculty of Science and Technology, School of Biosciences and Biotechnology, Universiti Kebangsaan Malaysia Bangi, Malaysia.

Burkholderia cenocepacia infection often leads to fatal cepacia syndrome in cystic fibrosis patients. However, antibiotic therapy rarely results in complete eradication of the pathogen due to its intrinsic resistance to many clinically available antibiotics. Recent attention has turned to the identification of essential genes as the proteins encoded by these genes may serve as potential targets for development of novel antimicrobials. In this study, we utilized TraDIS (Transposon Directed Insertion-site Sequencing) as a genome-wide screening tool to facilitate the identification of B. cenocepacia genes essential for its growth and viability. A transposon mutant pool consisting of approximately 500,000 mutants was successfully constructed, with more than 400,000 unique transposon insertion sites identified by computational analysis of TraDIS datasets. The saturated library allowed for the identification of 383 genes that were predicted to be essential in B. cenocepacia. We extended the application of TraDIS to identify conditionally essential genes required for in vitro growth and revealed an additional repertoire of 439 genes to be crucial for B. cenocepacia growth under nutrient-depleted conditions. The library of B. cenocepacia mutants can subsequently be subjected to various biologically related conditions to facilitate the discovery of genes involved in niche adaptation as well as pathogenicity and virulence.
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http://dx.doi.org/10.3389/fmicb.2016.01288DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4993015PMC
September 2016

Detection of Burkholderia pseudomallei toxin-mediated inhibition of protein synthesis using a Caenorhabditis elegans ugt-29 biosensor.

Sci Rep 2016 06 7;6:27475. Epub 2016 Jun 7.

School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi Selangor, Malaysia.

Toxins are believed to play a crucial role in Burkholderia pseudomallei pathogenicity, however to date, only a few have been identified. The discovery of additional toxic molecules is limited by the lack of a sensitive indicator of B. pseudomallei toxicity. Previously, from a whole genome transcriptome analysis of B. pseudomallei-infected Caenorhabditis elegans, we noted significant overexpression of a number of worm genes encoding detoxification enzymes, indicating the host's attempt to clear bacterial toxic molecules. One of these genes, ugt-29, a family member of UDP-glucuronosyltransferases, was the most robustly induced phase II detoxification gene. In this study, we show that strong induction of ugt-29 is restricted to infections by the most virulent species among the pathogens tested. We also noted that ugt-29 is activated upon disruption of host protein synthesis. Hence, we propose that UGT-29 could be a promising biosensor to detect B. pseudomallei toxins that compromise host protein synthesis. The identification of bactobolin, a polyketide-peptide hybrid molecule, as a toxic molecule of B. pseudomallei further verifies the utilization of this surveillance system to search for bacterial toxins. Hence, a ugt-29 based reporter should be useful in screening for other molecules that inhibit host protein synthesis.
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http://dx.doi.org/10.1038/srep27475DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4895344PMC
June 2016

Targeting Staphylococcus aureus Toxins: A Potential form of Anti-Virulence Therapy.

Toxins (Basel) 2016 Mar 15;8(3). Epub 2016 Mar 15.

School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan, Malaysia.

Staphylococcus aureus is an opportunistic pathogen and the leading cause of a wide range of severe clinical infections. The range of diseases reflects the diversity of virulence factors produced by this pathogen. To establish an infection in the host, S. aureus expresses an inclusive set of virulence factors such as toxins, enzymes, adhesins, and other surface proteins that allow the pathogen to survive under extreme conditions and are essential for the bacteria's ability to spread through tissues. Expression and secretion of this array of toxins and enzymes are tightly controlled by a number of regulatory systems. S. aureus is also notorious for its ability to resist the arsenal of currently available antibiotics and dissemination of various multidrug-resistant S. aureus clones limits therapeutic options for a S. aureus infection. Recently, the development of anti-virulence therapeutics that neutralize S. aureus toxins or block the pathways that regulate toxin production has shown potential in thwarting the bacteria's acquisition of antibiotic resistance. In this review, we provide insights into the regulation of S. aureus toxin production and potential anti-virulence strategies that target S. aureus toxins.
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http://dx.doi.org/10.3390/toxins8030072DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4810217PMC
March 2016

Characterization of Burkholderia pseudomallei protein BPSL1375 validates the Putative hemolytic activity of the COG3176 N-Acyltransferase family.

BMC Microbiol 2015 Nov 23;15:270. Epub 2015 Nov 23.

School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor, Malaysia.

Background: There are still numerous protein subfamilies within families and superfamilies that do not yet have conclusive empirical experimental evidence providing a specific function. These proteins persist in databases with the annotation of a specific 'putative' function made by association with discernible features in the protein sequence.

Results: Here, we report the characterization of one such protein produced by the pathogenic soil bacterium Burkholderia pseudomallei, BPSL1375, which provided evidence for putative hemolysins in the COG3176 family to have experimentally validated hemolytic activity. BPSL1375 can be classified into the N-acyltransferase superfamily, specifically to members of the COG3176 family. Sequence alignments identified seven highly conserved residues (Arg54, Phe58, Asp75, Asp78, Arg99, Glu132 and Arg135), of which several have been implicated with N-acyltransferase activity in previously characterized examples. Using the 3D model of an N-acyltransferase example as a reference, an acyl homoserine lactone synthase, we generated 3D structure models for mutants of six of the seven N-acyltransferase conserved residues (R54, D75, D78, R99, E132 and R135). Both the R99 and R135 mutants resulted in a loss of hemolytic activity while mutations at the other five positions resulted in either reduction or increment in hemolytic activity.

Conclusions: The implication of residues previously characterized to be important for N-acyltransferase activity to hemolytic activity for the COG3176 family members of the N-acyltransferase provides validation of the correct placement of the hemolytic capability annotation within the N-acyltransferase superfamily.
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http://dx.doi.org/10.1186/s12866-015-0604-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4657338PMC
November 2015

Development of repeatable arrays of proteins using immobilized DNA microplate (RAPID-M) technology.

BMC Res Notes 2015 Nov 12;8:669. Epub 2015 Nov 12.

Malaysia Genome Institute, 43000, Bangi, Selangor DE, Malaysia.

Background: Protein microarrays have enormous potential as in vitro diagnostic tools stemming from the ability to miniaturize whilst generating maximum evaluation of diagnostically relevant information from minute amounts of sample. In this report, we present a method known as repeatable arrays of proteins using immobilized DNA microplates (RAPID-M) for high-throughput in situ protein microarray fabrication. The RAPID-M technology comprises of cell-free expression using immobilized DNA templates and in situ protein purification onto standard microarray slides.

Results: To demonstrate proof-of-concept, the repeatable protein arrays developed using our RAPID-M technology utilized green fluorescent protein (GFP) and a bacterial outer membrane protein (OmpA) as the proteins of interest for microarray fabrication. Cell-free expression of OmpA and GFP proteins using beads-immobilized DNA yielded protein bands with the expected molecular sizes of 27 and 30 kDa, respectively. We demonstrate that the beads-immobilized DNA remained stable for at least four cycles of cell-free expression. The OmpA and GFP proteins were still functional after in situ purification on the Ni-NTA microarray slide.

Conclusion: The RAPID-M platform for protein microarray fabrication of two different representative proteins was successfully developed.
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http://dx.doi.org/10.1186/s13104-015-1637-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4642736PMC
November 2015

Highly Sensitive Aluminium(III) Ion Sensor Based on a Self-assembled Monolayer on a Gold Nanoparticles Modified Screen-printed Carbon Electrode.

Anal Sci 2015 ;31(10):997-1003

School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM).

A new approach for the development of a highly sensitive aluminium(III) ion sensor via the preconcentration of aluminium(III) ion with a self-assembled monolayer on a gold nanoparticles modified screen-printed carbon electrode and current mediation by potassium ferricyanide redox behavior during aluminium(III) ion binding has been attempted. A monolayer of mercaptosuccinic acid served as an effective complexation ligand for the preconcentration of trace aluminium; this led to an enhancement of aluminium(III) ion capture and thus improved the sensitivity of the sensor with a detection limit of down to the ppb level. Under the optimum experimental conditions, the sensor exhibited a wide linear dynamic range from 0.041 to 12.4 μM. The lower detection limit of the developed sensor was 0.037 μM (8.90 ppb) using a 10 min preconcentration time. The sensor showed excellent selectivity towards aluminium(III) ion over other interference ions.
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http://dx.doi.org/10.2116/analsci.31.997DOI Listing
July 2016

Global transcriptional analysis of Burkholderia pseudomallei high and low biofilm producers reveals insights into biofilm production and virulence.

BMC Genomics 2015 Jun 20;16:471. Epub 2015 Jun 20.

School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor Darul Ehsan, Malaysia.

Background: Chronic bacterial infections occur as a result of the infecting pathogen's ability to live within a biofilm, hence escaping the detrimental effects of antibiotics and the immune defense system. Burkholderia pseudomallei, a gram-negative facultative pathogen, is distinctive in its ability to survive within phagocytic and non-phagocytic cells, to persist in vivo for many years and subsequently leading to relapse as well as the development of chronic disease. The capacity to persist has been attributed to the pathogen's ability to form biofilm. However, the underlying biology of B. pseudomallei biofilm development remains unresolved.

Results: We utilised RNA-Sequencing to identify genes that contribute to B. pseudomallei biofilm phenotype. Transcriptome analysis of a high and low biofilm producer identified 563 differentially regulated genes, implying that expression of ~9.5% of the total B. pseudomallei gene content was altered during biofilm formation. Genes involved in surface-associated motility, surface composition and cell wall biogenesis were over-expressed and probably play a role in the initial attachment of biofilms. Up-regulation of genes related to two component signal transduction systems and a denitrification enzyme pathway suggest that the B. pseudomallei high biofilm producer is able to sense the surrounding environmental conditions and regulate the production of extracellular polymeric substance matrix, a hallmark of microbial biofilm formation.

Conclusions: The transcriptome profile described here provides the first comprehensive view of genes that contribute to the biofilm phenotype in B. pseudomallei.
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http://dx.doi.org/10.1186/s12864-015-1692-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4474458PMC
June 2015

Curcumin rescues Caenorhabditis elegans from a Burkholderia pseudomallei infection.

Front Microbiol 2015 10;6:290. Epub 2015 Apr 10.

Faculty of Science and Technology, School of Biosciences and Biotechnology, National University of Malaysia Bangi, Malaysia.

The tropical pathogen Burkholderia pseudomallei requires long-term parenteral antimicrobial treatment to eradicate the pathogen from an infected patient. However, the development of antibiotic resistance is emerging as a threat to this form of treatment. To meet the need for alternative therapeutics, we proposed a screen of natural products for compounds that do not kill the pathogen, but in turn, abrogate bacterial virulence. We suggest that the use of molecules or compounds that are non-bactericidal (bacteriostatic) will reduce or abolish the development of resistance by the pathogen. In this study, we adopted the established Caenorhabditis elegans-B. pseudomallei infection model to screen a collection of natural products for any that are able to extend the survival of B. pseudomallei infected worms. Of the 42 natural products screened, only curcumin significantly improved worm survival following infection whilst not affecting bacterial growth. This suggested that curcumin promoted B. pseudomallei-infected worm survival independent of pathogen killing. To validate that the protective effect of curcumin was directed toward the pathogen, bacteria were treated with curcumin prior to infection. Worms fed with curcumin-treated bacteria survived with a significantly extended mean-time-to-death (p < 0.0001) compared to the untreated control. In in vitro assays, curcumin reduced the activity of known virulence factors (lipase and protease) and biofilm formation. To determine if other bacterial genes were also regulated in the presence of curcumin, a genome-wide transcriptome analysis was performed on curcumin-treated pathogen. A number of genes involved in iron acquisition and transport as well as genes encoding hypothetical proteins were induced in the presence of curcumin. Thus, we propose that curcumin may attenuate B. pseudomallei by modulating the expression of a number of bacterial proteins including lipase and protease as well as biofilm formation whilst concomitantly regulating iron transport and other proteins of unknown function.
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http://dx.doi.org/10.3389/fmicb.2015.00290DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4392299PMC
April 2015

AFN-1252 is a potent inhibitor of enoyl-ACP reductase from Burkholderia pseudomallei--Crystal structure, mode of action, and biological activity.

Protein Sci 2015 May 2;24(5):832-40. Epub 2015 Apr 2.

Aurigene Discovery Technologies Ltd, 39-40, KIADB Industrial area, Electronic city Phase II, Hosur Road, Bangalore, 560 100, India.

Melioidosis is a tropical bacterial infection caused by Burkholderia pseudomallei (B. pseudomallei; Bpm), a Gram-negative bacterium. Current therapeutic options are largely limited to trimethoprim-sulfamethoxazole and β-lactam drugs, and the treatment duration is about 4 months. Moreover, resistance has been reported to these drugs. Hence, there is a pressing need to develop new antibiotics for Melioidosis. Inhibition of enoyl-ACP reducatase (FabI), a key enzyme in the fatty acid biosynthesis pathway has shown significant promise for antibacterial drug development. FabI has been identified as the major enoyl-ACP reductase present in B. pseudomallei. In this study, we evaluated AFN-1252, a Staphylococcus aureus FabI inhibitor currently in clinical development, for its potential to bind to BpmFabI enzyme and inhibit B. pseudomallei bacterial growth. AFN-1252 stabilized BpmFabI and inhibited the enzyme activity with an IC50 of 9.6 nM. It showed good antibacterial activity against B. pseudomallei R15 strain, isolated from a melioidosis patient (MIC of 2.35 mg/L). X-ray structure of BpmFabI with AFN-1252 was determined at a resolution of 2.3 Å. Complex of BpmFabI with AFN-1252 formed a symmetrical tetrameric structure with one molecule of AFN-1252 bound to each monomeric subunit. The kinetic and thermal melting studies supported the finding that AFN-1252 can bind to BpmFabI independent of cofactor. The structural and mechanistic insights from these studies might help the rational design and development of new FabI inhibitors.
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http://dx.doi.org/10.1002/pro.2655DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4420531PMC
May 2015

Transcriptome analysis of Burkholderia pseudomallei T6SS identifies Hcp1 as a potential serodiagnostic marker.

Microb Pathog 2015 Feb 20;79:47-56. Epub 2015 Jan 20.

School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia. Electronic address:

Burkholderia pseudomallei, the causative agent of melioidosis, is able to survive extreme environments and utilizes various virulence factors for survival and pathogenicity. To compete and survive within these different ecological niches, B. pseudomallei has evolved specialized pathways, including the Type VI secretion systems (T6SSs), that have a role in pathogenesis as well as interbacterial interactions. We examined the expression profile of B. pseudomallei T6SS six gene clusters during infection of U937 macrophage cells. T6SS-5 was robustly transcribed while the other five clusters were not significantly regulated proposing the utility of T6SS-5 as a potential biomarker of exposure to B. pseudomallei. Transcription of T6SS regulators VirAG and BprB was also not significant during infection when compared to bacteria grown in culture. Guided by these findings, three highly expressed T6SS genes, tssJ-4, hcp1 and tssE-5, were expressed as recombinant proteins and screened against melioidosis patient sera by western analysis and ELISA. Only Hcp1 was reactive by both types of analysis. The recombinant Hcp1 protein was further evaluated against a cohort of melioidosis patients (n = 32) and non-melioidosis individuals (n = 20) sera and the data clearly indicates a higher sensitivity (93.7%) and specificity (100%) for Hcp1 compared to bacterial lysate. The detection of anti-Hcp1 antibodies in patients' sera indicating the presence of B. pseudomallei highlights the potential of Hcp1 to be further developed as a serodiagnostic marker for melioidosis.
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http://dx.doi.org/10.1016/j.micpath.2015.01.006DOI Listing
February 2015

Crystallization and preliminary crystallographic studies of the hypothetical protein BPSL1038 from Burkholderia pseudomallei.

Acta Crystallogr F Struct Biol Commun 2014 Dec 28;70(Pt 12):1697-700. Epub 2014 Nov 28.

Institute of Systems Biology, Universiti Kebangsaan Malaysia (UKM), Bangi, Selangor 43600, Malaysia.

Melioidosis is an infectious disease caused by the pathogenic bacterium Burkholderia pseudomallei. Whole-genome sequencing revealed that the B. pseudomallei genome includes 5855 coding DNA sequences (CDSs), of which ∼25% encode hypothetical proteins. A pathogen-associated hypothetical protein, BPSL1038, was overexpressed in Escherichia coli, purified and crystallized using vapour-diffusion methods. A BPSL1038 protein crystal that grew using sodium formate as precipitant diffracted to 1.55 Å resolution. It belonged to space group C2221, with unit-cell parameters a = 85.36, b = 115.63, c = 46.73 Å. The calculated Matthews coefficient (VM) suggests that there are two molecules per asymmetric unit, with a solvent content of 48.8%.
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http://dx.doi.org/10.1107/S2053230X14025278DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4259243PMC
December 2014