Publications by authors named "Heng Ku"

7 Publications

  • Page 1 of 1

Novel Drexlerviridae bacteriophage KMI8 with specific lytic activity against Klebsiella michiganensis and its biofilms.

PLoS One 2021 7;16(9):e0257102. Epub 2021 Sep 7.

Department of Pharmacy and Biomedical Science, La Trobe Institute for Molecular Science, La Trobe University, Victoria, Australia.

The bacterial genus Klebsiella includes the closely related species K. michiganensis, K. oxytoca and K. pneumoniae, which are capable of causing severe disease in humans. In this report we describe the isolation, genomic and functional characterisation of the lytic bacteriophage KMI8 specific for K. michiganensis. KMI8 belongs to the family Drexlerviridae, and has a novel genome which shares very little homology (71.89% identity over a query cover of only 8%) with that of its closest related bacteriophages (Klebsiella bacteriophage LF20 (MW417503.1); Klebsiella bacteriophage 066039 (MW042802.1). KMI8, which possess a putative endosialidase (depolymerase) enzyme, was shown to be capable of degrading mono-biofilms of a strain of K. michiganensis that carried the polysaccharide capsule KL70 locus. This is the first report of a lytic bacteriophage for K. michiganensis, which is capable of breaking down a biofilm of this species.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0257102PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8423285PMC
September 2021

Isolation and Functional Characterization of Fusobacterium nucleatum Bacteriophage.

Methods Mol Biol 2021 ;2327:51-68

Department of Pharmacy and Biomedical Sciences, La Trobe Institute for Molecular Science, La Trobe University, Bendigo, VIC, Australia.

Bacteriophages are viruses that specifically lyse bacteria. They have demonstrated potential in applications as antibacterial agents in medicine, agriculture, and environmental remediation. Due to the complex and dynamic nature of the oral microbiome, antibiotic treatment of chronic, polymicrobial oral diseases may lead to dysbiosis. In these diseases, bacteriophages may provide targeted activity against oral bacteria without such disruption to the broader microbial community. In this chapter, we describe the methods for screening samples that may contain bacteriophages against oral pathogenic bacteria, and using the example of FNU1, the bacteriophage we isolated against Fusobacterium nucleatum, describe the process of bacteriophage purification and characterization.
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http://dx.doi.org/10.1007/978-1-0716-1518-8_4DOI Listing
January 2021

Lytic Bacteriophage EFA1 Modulates HCT116 Colon Cancer Cell Growth and Upregulates ROS Production in an Co-culture System.

Front Microbiol 2021 31;12:650849. Epub 2021 Mar 31.

Department of Pharmacy and Biomedical Sciences, La Trobe Institute for Molecular Science, La Trobe University, Bendigo, VIC, Australia.

is an opportunistic pathogen in the gut microbiota that's associated with a range of difficult to treat nosocomial infections. It is also known to be associated with some colorectal cancers. Its resistance to a range of antibiotics and capacity to form biofilms increase its virulence. Unlike antibiotics, bacteriophages are capable of disrupting biofilms which are key in the pathogenesis of diseases such as UTIs and some cancers. In this study, bacteriophage EFA1, lytic against , was isolated and its genome fully sequenced and analyzed . Electron microscopy images revealed EFA1 to be a . The bacteriophage was functionally assessed and shown to disrupt biofilms as well as modulate the growth stimulatory effects of in a HCT116 colon cancer cell co-culture system, possibly via the effects of ROS. The potential exists for further testing of bacteriophage EFA1 in these systems as well as models.
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http://dx.doi.org/10.3389/fmicb.2021.650849DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8044584PMC
March 2021

Characterization of Novel Lytic Bacteriophages of Isolated from a Pneumonia Patient.

Viruses 2020 10 8;12(10). Epub 2020 Oct 8.

Department of Pharmacy and Biomedical Science, La Trobe Institute for Molecular Science, La Trobe University, Bendigo, Victoria 3552, Australia.

spp. are becoming increasingly associated with lung infections in patients suffering from cystic fibrosis (CF). , which is closely related to , has been isolated from the lungs of CF patients and other human infections. This article describes the isolation, morphology and characterization of two lytic bacteriophages specific for an strain isolated from a pneumonia patient. This host strain was the causal agent of hospital acquired pneumonia-the first clinical report of such an occurrence. Full genome sequencing revealed bacteriophage genomes ranging in size from 45901 to 46,328 bp. Transmission electron microscopy revealed that the two bacteriophages AMA1 and AMA2 belonged to the family. Host range analysis showed that their host range did not extend to . The possibility exists for future testing of such bacteriophages in the control of infections such as those seen in CF and other infections of the lungs. The incidence of antibiotic resistance in this genus highlights the importance of seeking adjuncts and alternatives in CF and other lung infections.
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http://dx.doi.org/10.3390/v12101138DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7600146PMC
October 2020

Novel Bacteriophages Capable of Disrupting Biofilms From Clinical Strains of .

Front Microbiol 2020 14;11:194. Epub 2020 Feb 14.

Department of Pharmacy and Biomedical Science, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia.

The increase in global warming has favored growth of a range of opportunistic environmental bacteria and allowed some of these to become more pathogenic to humans. is one such organism. Surviving in moist conditions in temperate climates, these bacteria have been associated with a range of diseases in humans, and in systemic infections can cause mortality in up to 46% of cases. Their capacity to form biofilms, carry antibiotic resistance mechanisms, and survive disinfection, has meant that they are not easily treated with traditional methods. Bacteriophage offer a possible alternative approach for controlling their growth. This study is the first to report the isolation and characterization of bacteriophages lytic against clinical strains of which carry intrinsic antibiotic resistance genes. Functionally, these novel bacteriophages were shown to be capable of disrupting biofilms caused by clinical isolates of The potential exists for these to be tested in clinical and environmental settings.
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http://dx.doi.org/10.3389/fmicb.2020.00194DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7033617PMC
February 2020

Genomic, morphological and functional characterisation of novel bacteriophage FNU1 capable of disrupting Fusobacterium nucleatum biofilms.

Sci Rep 2019 06 24;9(1):9107. Epub 2019 Jun 24.

Department of Pharmacy and Biomedical Sciences, La Trobe Institute for Molecular Science, La Trobe University, Victoria, Australia.

Fusobacterium nucleatum is an important oral bacterium that has been linked to the development of chronic diseases such as periodontitis and colorectal cancer. In periodontal disease, F. nucleatum forms the backbone of the polymicrobial biofilm and in colorectal cancer is implicated in aetiology, metastasis and chemotherapy resistance. The control of this bacteria may be important in assisting treatment of these diseases. With increased rates of antibiotic resistance globally, there is need for development of alternatives such as bacteriophages, which may complement existing therapies. Here we describe the morphology, genomics and functional characteristics of FNU1, a novel bacteriophage lytic against F. nucleatum. Transmission electron microscopy revealed FNU1 to be a large Siphoviridae virus with capsid diameter of 88 nm and tail of approximately 310 nm in length. Its genome was 130914 bp, with six tRNAs, and 8% of its ORFs encoding putative defence genes. FNU1 was able to kill cells within and significantly reduce F. nucleatum biofilm mass. The identification and characterisation of this bacteriophage will enable new possibilities for the treatment and prevention of F. nucleatum associated diseases to be explored.
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http://dx.doi.org/10.1038/s41598-019-45549-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6591296PMC
June 2019

Time dependent response of daunorubicin on cytotoxicity, cell cycle and DNA repair in acute lymphoblastic leukaemia.

BMC Cancer 2019 Feb 27;19(1):179. Epub 2019 Feb 27.

Department of Pharmacy and Applied Sciences, La Trobe Institute for Molecular Science (LIMS), La Trobe University, P.O. Box 199, Bendigo, Victoria, Australia.

Background: Daunorubicin is commonly used in the treatment of acute lymphoblastic leukaemia (ALL). The aim of this study was to explore the kinetics of double strand break (DSB) formation of three ALL cell lines following exposure to daunorubicin and to investigate the effects of daunorubicin on the cell cycle and the protein kinases involved in specific checkpoints following DNA damage and recovery periods.

Methods: Three ALL cell lines CCRF-CEM and MOLT-4 derived from T lymphocytes and SUP-B15 derived from B lymphocytes were examined following 4 h treatment with daunorubicin chemotherapy and 4, 12 and 24 h recovery periods. Cell viability was measured via MTT (3-(4,5-dimethylthiazol-2-yl)-2-5 diphenyltetrazolium bromide) assay, reactive oxygen species (ROS) production by flow cytometry, double stranded DNA breaks by detecting γH2AX levels while stages of the cell cycle were detected following propidium iodide staining and flow cytometry. Western blotting was used to detect specific proteins while RNA was extracted from all cell lines and converted to cDNA to sequence Ataxia-telangiectasia mutated (ATM).

Results: Daunorubicin induced different degrees of toxicity in all cell lines and consistently generated reactive oxygen species. Daunorubicin was more potent at inducing DSB in MOLT-4 and CCRF-CEM cell lines while SUP-B15 cells showed delays in DSB repair and significantly more resistance to daunorubicin compared to the other cell lines as measured by γH2AX assay. Daunorubicin also causes cell cycle arrest in all three cell lines at different checkpoints at different times. These effects were not due to mutations in ATM as sequencing revealed none in any of the three cell lines. However, p53 was phosphorylated at serine 15 only in CCRF-CEM and MOLT-4 but not in SUP-B15 cells. The lack of active p53 may be correlated to the increase of SOD2 in SUP-B15 cells.

Conclusions: The delay in DSB repair and lower sensitivity to daunorubicin seen in the B lymphocyte derived SUP-B15 cells could be due to loss of function of p53 that may be correlated to increased expression of SOD2 and lower ROS production.
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http://dx.doi.org/10.1186/s12885-019-5377-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6391779PMC
February 2019
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