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Muangpat P, Meesil W, Ngoenkam J, Teethaisong Y, Thummeepak R, Sitthisak S, Tandhavanant S, Chantratita N, Bode HB, Vitta A, Thanwisai A. Genome analysis of secondary metabolite‑biosynthetic gene clusters of Photorhabdus akhurstii subsp. akhurstii and its antibacterial activity against antibiotic-resistant bacteria. PLoS One 2022; 17:e0274956. [PMID: 36129957 PMCID: PMC9491552 DOI: 10.1371/journal.pone.0274956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 09/08/2022] [Indexed: 11/27/2022] Open
Abstract
Xenorhabdus and Photorhabdus can produce a variety of secondary metabolites with broad spectrum bioactivity against microorganisms. We investigated the antibacterial activity of Xenorhabdus and Photorhabdus against 15 antibiotic-resistant bacteria strains. Photorhabdus extracts had strong inhibitory the growth of Methicillin-resistant Staphylococcus aureus (MRSA) by disk diffusion. The P. akhurstii s subsp. akhurstii (bNN168.5_TH) extract showed lower minimum inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC). The interaction between either P. akhurstii subsp. akhurstii (bNN141.3_TH) or P. akhurstii subsp. akhurstii (bNN168.5_TH) or P. hainanensis (bNN163.3_TH) extract in combination with oxacillin determined by checkerboard assay exhibited partially synergistic interaction with fractional inhibitory concentration index (FICI) of 0.53. Time-killing assay for P. akhurstii subsp. akhurstii (bNN168.5_TH) extract against S. aureus strain PB36 significantly decreased cell viability from 105 CFU/ml to 103 CFU/ml within 30 min (P < 0.001, t-test). Transmission electron microscopic investigation elucidated that the bNN168.5_TH extract caused treated S. aureus strain PB36 (MRSA) cell membrane damage. The biosynthetic gene clusters of the bNN168.5_TH contained non-ribosomal peptide synthetase cluster (NRPS), hybrid NRPS-type l polyketide synthase (PKS) and siderophore, which identified potentially interesting bioactive products: xenematide, luminmide, xenortide A-D, luminmycin A, putrebactin/avaroferrin and rhizomide A-C. This study demonstrates that bNN168.5_TH showed antibacterial activity by disrupting bacterial cytoplasmic membrane and the draft genome provided insights into the classes of bioactive products. This also provides a potential approach in developing a novel antibacterial agent.
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Affiliation(s)
- Paramaporn Muangpat
- Faculty of Medical Science, Department of Microbiology and Parasitology, Naresuan University, Phitsanulok, Thailand
| | - Wipanee Meesil
- Faculty of Medical Science, Department of Microbiology and Parasitology, Naresuan University, Phitsanulok, Thailand
| | - Jatuporn Ngoenkam
- Faculty of Medical Science, Department of Microbiology and Parasitology, Naresuan University, Phitsanulok, Thailand
| | - Yothin Teethaisong
- Faculty of Allied Health Sciences, Department of Biomedical Sciences, Burapha University, Chonburi, Thailand
- Research Unit for Sensor Inovation (RUSI), Burapha University, Chon Buri, Thailand
| | - Rapee Thummeepak
- Faculty of Medical Science, Department of Microbiology and Parasitology, Naresuan University, Phitsanulok, Thailand
| | - Sutthirat Sitthisak
- Faculty of Medical Science, Department of Microbiology and Parasitology, Naresuan University, Phitsanulok, Thailand
| | - Sarunporn Tandhavanant
- Faculty of Tropical Medicine, Department of Microbiology and Immunology, Mahidol University, Bangkok, Thailand
| | - Narisara Chantratita
- Faculty of Tropical Medicine, Department of Microbiology and Immunology, Mahidol University, Bangkok, Thailand
| | - Helge B. Bode
- Molekulare Biotechnologie, Goethe Universität Frankfurt, Frankfurt am Main, Germany
- Department of Natural Products in Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Apichat Vitta
- Faculty of Medical Science, Department of Microbiology and Parasitology, Naresuan University, Phitsanulok, Thailand
- Faculty of Sciences, Center of Excellence for Biodiversity, Naresuan University, Phitsanulok, Thailand
- Faculty of Medical Science, Centre of Excellence in Medical Biotechnology (CEMB), Naresuan University, Phitsanulok, Thailand
| | - Aunchalee Thanwisai
- Faculty of Medical Science, Department of Microbiology and Parasitology, Naresuan University, Phitsanulok, Thailand
- Faculty of Sciences, Center of Excellence for Biodiversity, Naresuan University, Phitsanulok, Thailand
- Faculty of Medical Science, Centre of Excellence in Medical Biotechnology (CEMB), Naresuan University, Phitsanulok, Thailand
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Vinayak V, Khan MJ, Varjani S, Saratale GD, Saratale RG, Bhatia SK. Microbial fuel cells for remediation of environmental pollutants and value addition: Special focus on coupling diatom microbial fuel cells with photocatalytic and photoelectric fuel cells. J Biotechnol 2021; 338:5-19. [PMID: 34245783 DOI: 10.1016/j.jbiotec.2021.07.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 06/28/2021] [Accepted: 07/05/2021] [Indexed: 12/11/2022]
Abstract
With the advent of global industrialisation and adaptation of smart life there is rise in anthropogenic pollution especially in water. Remediation of the pollutants (such as metals, and dyes) present in industrial effluents is possible via microbes and algae present in the environment. Microbes are used in a microbial fuel cell (MFC) for remediation of various organic and inorganic pollutants. However, for industrial scale application coupling the MFCs with photocatalytic and photoelectric fuel cell has a potential in improving the output of power. It can also be used for remediation of pollutants more expeditiously, conserving fossil fuels, cleaning environment, hence making the coupled hybrid fuel cell to run economically. Furthermore, such MFC inbuilt with algae in living or powder form give additional value addition products like biofuel, polysaccharides, biopolymers, and polyhydroxy alkanoates etc. This review provides bird's eye view on the removal of environmental pollutants by different biological sources like bacteria and algae. The article is focussed on diatoms as potential algae since they are rich source of crude oil and high value added products in a hybrid photocatalytic MFC. It also covers bottle necks, challenges and future in this field of research.
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Affiliation(s)
- Vandana Vinayak
- Diatom Nanoengineering and Metabolism Laboratory (DNM), School of Applied Sciences, Dr. Harisingh Gour Vishwavidyalaya (A Central University), Sagar, Madhya Pradesh, 470003, India
| | - Mohd Jahir Khan
- Diatom Nanoengineering and Metabolism Laboratory (DNM), School of Applied Sciences, Dr. Harisingh Gour Vishwavidyalaya (A Central University), Sagar, Madhya Pradesh, 470003, India
| | - Sunita Varjani
- Gujarat Pollution Control Board, Gandhinagar, Gujarat, 382 010, India.
| | - Ganesh Dattatraya Saratale
- Department of Food Science and Biotechnology, Dongguk University-Seoul, Ilsandong-gu, Goyang-si, Gyeonggido, 10326, Republic of Korea
| | - Rijuta Ganesh Saratale
- Research Institute of Biotechnology and Medical Converged Science, Dongguk University-Seoul, Ilsandong-gu, Goyang-si, Gyeonggido, 10326, Republic of Korea
| | - Shashi Kant Bhatia
- Department of Biological Engineering, Konkuk University, Seoul, 05029, Republic of Korea
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Novel Antibiotics Targeting Bacterial Replicative DNA Polymerases. Antibiotics (Basel) 2020; 9:antibiotics9110776. [PMID: 33158178 PMCID: PMC7694242 DOI: 10.3390/antibiotics9110776] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/31/2020] [Accepted: 11/02/2020] [Indexed: 12/15/2022] Open
Abstract
Multidrug resistance is a worldwide problem that is an increasing threat to global health. Therefore, the development of new antibiotics that inhibit novel targets is of great urgency. Some of the most successful antibiotics inhibit RNA transcription, RNA translation, and DNA replication. Transcription and translation are inhibited by directly targeting the RNA polymerase or ribosome, respectively. DNA replication, in contrast, is inhibited indirectly through targeting of DNA gyrases, and there are currently no antibiotics that inhibit DNA replication by directly targeting the replisome. This contrasts with antiviral therapies where the viral replicases are extensively targeted. In the last two decades there has been a steady increase in the number of compounds that target the bacterial replisome. In particular a variety of inhibitors of the bacterial replicative polymerases PolC and DnaE have been described, with one of the DNA polymerase inhibitors entering clinical trials for the first time. In this review we will discuss past and current work on inhibition of DNA replication, and the potential of bacterial DNA polymerase inhibitors in particular as attractive targets for a new generation of antibiotics.
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Jiang X, Huang Y. Curcumin Derivative C086 Combined with Cisplatin Inhibits Proliferation of Osteosarcoma Cells. Med Sci Monit 2020; 26:e924507. [PMID: 32734935 PMCID: PMC7414526 DOI: 10.12659/msm.924507] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Background Curcumin derivative C086 (cur C086) is a potential chemotherapeutic agent for patients with osteosarcoma. In this study, the effects of cur C086 combined with cisplatin on the biological processes of osteosarcoma cells were investigated. Material/Methods In this study, expression of BMIL1 was detected by real-time quantitative reverse transcription polymerase chain reaction and Western blotting in MG-63 cells treated with cur C086+cisplatin. Functions of cur C086+cisplatin on proliferation ability, apoptosis response, and metastatic potential of MG-63 cells were determined by MTT, flow cytometry, Hoechst 33258 staining and Transwell assays, respectively. In additionally, expression of P16, E-cadherin, epidermal growth factor (EGFR), and Notch1 was measured by Western blotting. Results Expression of BMIL1 decreased significantly in MG-63 cells treated with cur C086 (20 μM)+cisplatin (1.28 nM). Treatment with cur C086+cisplatin considerably inhibited growth, migration, and invasion potential in MG-63 cells, whereas apoptosis was obviously upregulated. Moreover, cur C086+cisplatin suppressed BMIL1 expression or its potential downstream targets, P16, E-cadherin, EGFR, and Notch1. Conclusions The current results demonstrate that combined treatment with cur C086+cisplatin may be an effective form of chemotherapy for patients with osteosarcoma.
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Affiliation(s)
- Xi Jiang
- Key Laboratory for Biorheological Science and Technology of Ministry of Education (Chongqing University), Chongqing University Cancer Hospital, Chongqing, China (mainland)
| | - Yulin Huang
- Department of Clinical Laboratory, The Traditional Chinese Medicine Hospital of Wuxi, Chongqing, China (mainland)
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Zhang B, Zhang Y, Li R, Li J, Lu X, Zhang Y. Oncolytic adenovirus Ad11 enhances the chemotherapy effect of cisplatin on osteosarcoma cells by inhibiting autophagy. Am J Transl Res 2020; 12:105-117. [PMID: 32051740 PMCID: PMC7013210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 01/03/2020] [Indexed: 06/10/2023]
Abstract
Targeted oncolytic adenoviruses can selectively replicate in cancer cells; combined with traditional chemotherapy drugs, this approach is expected to become an important treatment method for overcoming the current bottleneck of osteosarcoma treatment. Here, we investigate the effect of oncolytic adenovirus Ad11 combined with cisplatin on autophagy in osteosarcoma cells. Immunohistochemistry was used to detect CD46 expression in patients with osteosarcoma. A cytotoxicity assay was employed to detect the killing effect of Ad11, cisplatin and their combination on osteosarcoma cells under different time scenarios. Expression of autophagy proteins Beclin1, ATG3, and LC3A/B under treatment of osteosarcoma cells with Ad11, cisplatin and their combination under different time scenarios was detected by immunofluorescence and western blotting. We found that the oncolytic adenovirus Ad11 synergizes with cisplatin to kill osteosarcoma cells and that the synergistic effect was greatest when cells were first treated with Ad11. This synergy is due to oncolytic adenovirus Ad11-mediated inhibition of autophagy, which enhanced the sensitivity of cells to chemotherapy. In conclusion, this study provides evidence that the oncolytic adenovirus Ad11 can enhance the effect of chemotherapy by inhibiting autophagy. The findings provide a cytological basis for the treatment of osteosarcoma with oncolytic adenovirus combined with cisplatin.
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Affiliation(s)
- Bin Zhang
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou UniversityZhengzhou 450052, Henan, The People’s Republic of China
| | - Yan Zhang
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou UniversityZhengzhou 450052, Henan, The People’s Republic of China
| | - Rongzhen Li
- Department of Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer MedicineGuangzhou 510060, Guangdong, The People’s Republic of China
| | - Jiazhen Li
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou UniversityZhengzhou 450052, Henan, The People’s Republic of China
| | - Xinchang Lu
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou UniversityZhengzhou 450052, Henan, The People’s Republic of China
| | - Yi Zhang
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou UniversityZhengzhou 450052, Henan, The People’s Republic of China
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Su S, Yin P, Li J, Chen G, Wang Y, Qu D, Li Z, Xue X, Luo X, Li M. In vitro and in vivo anti-biofilm activity of pyran derivative against Staphylococcus aureus and Pseudomonas aeruginosa. J Infect Public Health 2019; 13:791-799. [PMID: 31813834 DOI: 10.1016/j.jiph.2019.10.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 10/21/2019] [Accepted: 10/30/2019] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND The development of bacterial biofilm can cause severe chronic infections and antibiotic resistance. Therefore, it poses a significant threat to public health. Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) are two major pathogens that can cause biofilm-associated infections, which leads to the urgent necessity of developing new agents with biofilm-forming inhibitory ability. METHODS A series of pyran derivatives were synthesized and characterized, and their in vitro anti-biofilm activity against S. aureus and P. aeruginosa were measured by minimal biofilm inhibitory concentration assay and FITC dye staining. The in vivo antibiofilm therapeutical effects were evaluated in S. aureus induced tissue cage infection mice model and P. aeruginosa induced urinary tract catheter infection rat model. RESULTS Several pyran derivatives showed the in vitro anti-biofilm activity against S. aureus and P. aeruginosa, and the activity of these compounds was not mediated through the accessory gene regulator (agr) quorum sensing system of S. aureus. One of these pyran derivatives, namely 2-amino-4-(2,6-dichlorophenyl)-3-cyano-5-oxo-4H,5H-pyrano[3,2c]chromene, exhibited significant inhibitory biofilm-formation activity in S. aureus tissue cage infection mice model and in the P. aeruginosa-infected urinary tract catheters of experimental rats. CONCLUSIONS The data indicated that this pyran derivative is a possible lead compound that can be used for the development of novel anti-biofilm agents against S. aureus and P. aeruginosa infection.
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Affiliation(s)
- Shan Su
- Department of Pharmacology, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China
| | - Pengshuo Yin
- Department of Pharmacology, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China
| | - Jing Li
- The Key Laboratory for Surface Engineering and Remanufacturing in Shaanxi Province, School of Chemical Engineering, Xi'an University, Xi'an, 710065, China
| | - Guanghui Chen
- Department of Pharmacology, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China
| | - Yikun Wang
- Department of Pharmacology, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China
| | - Di Qu
- Department of Pharmacology, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China
| | - Zhoupeng Li
- Department of Pharmacology, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China
| | - Xiaoyan Xue
- Department of Pharmacology, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China
| | - Xiaoxing Luo
- Department of Pharmacology, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China.
| | - Mingkai Li
- Department of Pharmacology, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China; Precision Pharmacy & Drug Development Center, The Fourth Military Medical University, Xi'an, 710038, China.
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das Chagas Almeida A, Azevedo Rodrigues L, dos Santos Paulino G, Pereira Aguilar A, Andrade Almeida A, Olavo Ferreira S, Brandão GC, Viana Leite JP, de Oliveira Barros Ribon A. Prenylated flavonoid-enriched fraction from Maclura tinctoria shows biological activity against Staphylococcus aureus and protects Galleria mellonella larvae from bacterial infection. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2019; 19:189. [PMID: 31357964 PMCID: PMC6664575 DOI: 10.1186/s12906-019-2600-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 07/18/2019] [Indexed: 11/10/2022]
Abstract
BACKGROUND The Atlantic Forest biome extends along the entire Brazilian coast and is home to approximately 20,000 plant species, many of which are endemic; it is considered one of the hotspot regions of the planet. Several of these species are sources of natural products with biological activities that are still unknown. In this study, we evaluated the antimicrobial activity of 90 extracts derived from native Atlantic Forest tree species against Staphylococcus aureus, an important human and veterinary pathogen. METHODS Extracts from native Atlantic Forest tree species were evaluated for their antimicrobial activity against S. aureus by in vitro standard methods. Phytochemical fractionation of the extract from Maclura tinctoria was performed by liquid-liquid partitioning. LC-DAD-ESI-MS was used for identification of constituents in the most active fraction. Damage of cells and alterations in the permeability of cell membrane were determined by atomic force microscopy (AFM) and crystal violet uptake assay, respectively. In vivo antimicrobial activity was evaluated using Galleria mellonella larvae infected with S. aureus with survival data collected using the Kaplan-Meier method. RESULTS Among the organic or aqueous extracts tested here, 26 showed biological activity. Eight species showed relevant results, with a minimum inhibitory concentration (MIC) below 1 mg/mL. Antibacterial activity was registered for three species for the first time. An organic extract from Maclura tinctoria leaves showed the lowest MIC (0.08 mg/mL). Fractionation of this extract by liquid-liquid partitioning led to obtaining fraction 11FO d with a MIC of 0.04 mg/mL. This fraction showed strong activity against veterinary S. aureus isolates and contributed to the increased survival of Galleria mellonella larvae infected with S. aureus ATCC 29213. The bacterial surface was not altered by the presence of 11FO d, and no cell membrane damage was detected. The LC-DAD-ESI/MS analyses identified prenylated flavonoids as the major constituents responsible for the antibacterial activity of this active extract. CONCLUSION A fraction enriched in prenylated isoflavones and flavanones from M. tinctoria showed in vitro and in vivo efficacy as antistaphylococcal agents. These findings justify the need for further research to elucidate the mechanisms of action of these compounds.
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Reiche MA, Warner DF, Mizrahi V. Targeting DNA Replication and Repair for the Development of Novel Therapeutics against Tuberculosis. Front Mol Biosci 2017; 4:75. [PMID: 29184888 PMCID: PMC5694481 DOI: 10.3389/fmolb.2017.00075] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 10/31/2017] [Indexed: 12/11/2022] Open
Abstract
Mycobacterium tuberculosis is the etiological agent of tuberculosis (TB), an infectious disease which results in approximately 10 million incident cases and 1.4 million deaths globally each year, making it the leading cause of mortality from infection. An effective frontline combination chemotherapy exists for TB; however, this regimen requires the administration of four drugs in a 2 month long intensive phase followed by a continuation phase of a further 4 months with two of the original drugs, and is only effective for the treatment of drug-sensitive TB. The emergence and global spread of multidrug-resistant (MDR) as well as extensively drug-resistant (XDR) strains of M. tuberculosis, and the complications posed by co-infection with the human immunodeficiency virus (HIV) and other co-morbidities such as diabetes, have prompted urgent efforts to develop shorter regimens comprising new compounds with novel mechanisms of action. This demands that researchers re-visit cellular pathways and functions that are essential to M. tuberculosis survival and replication in the host but which are inadequately represented amongst the targets of current anti-mycobacterial agents. Here, we consider the DNA replication and repair machinery as a source of new targets for anti-TB drug development. Like most bacteria, M. tuberculosis encodes a complex array of proteins which ensure faithful and accurate replication and repair of the chromosomal DNA. Many of these are essential; so, too, are enzymes in the ancillary pathways of nucleotide biosynthesis, salvage, and re-cycling, suggesting the potential to inhibit replication and repair functions at multiple stages. To this end, we provide an update on the state of chemotherapeutic inhibition of DNA synthesis and related pathways in M. tuberculosis. Given the established links between genotoxicity and mutagenesis, we also consider the potential implications of targeting DNA metabolic pathways implicated in the development of drug resistance in M. tuberculosis, an organism which is unusual in relying exclusively on de novo mutations and chromosomal rearrangements for evolution, including the acquisition of drug resistance. In that context, we conclude by discussing the feasibility of targeting mutagenic pathways in an ancillary, “anti-evolution” strategy aimed at protecting existing and future TB drugs.
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Affiliation(s)
- Michael A Reiche
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, Department of Pathology, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Digby F Warner
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, Department of Pathology, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Valerie Mizrahi
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, Department of Pathology, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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High-fidelity DNA replication in Mycobacterium tuberculosis relies on a trinuclear zinc center. Nat Commun 2017; 8:855. [PMID: 29021523 PMCID: PMC5636811 DOI: 10.1038/s41467-017-00886-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 08/02/2017] [Indexed: 01/07/2023] Open
Abstract
High-fidelity DNA replication depends on a proofreading 3′–5′ exonuclease that is associated with the replicative DNA polymerase. The replicative DNA polymerase DnaE1 from the major pathogen Mycobacterium tuberculosis (Mtb) uses its intrinsic PHP-exonuclease that is distinct from the canonical DEDD exonucleases found in the Escherichia coli and eukaryotic replisomes. The mechanism of the PHP-exonuclease is not known. Here, we present the crystal structure of the Mtb DnaE1 polymerase. The PHP-exonuclease has a trinuclear zinc center, coordinated by nine conserved residues. Cryo-EM analysis reveals the entry path of the primer strand in the PHP-exonuclease active site. Furthermore, the PHP-exonuclease shows a striking similarity to E. coli endonuclease IV, which provides clues regarding the mechanism of action. Altogether, this work provides important insights into the PHP-exonuclease and reveals unique properties that make it an attractive target for novel anti-mycobacterial drugs. The polymerase and histidinol phosphatase (PHP) domain in the DNA polymerase DnaE1 is essential for mycobacterial high-fidelity DNA replication. Here, the authors determine the DnaE1 crystal structure, which reveals the PHP-exonuclease mechanism that can be exploited for antibiotic development.
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Wang G, Feng H, Gao A, Hao Q, Jin W, Peng X, Li W, Wu G, Chu PK. Extracellular Electron Transfer from Aerobic Bacteria to Au-Loaded TiO2 Semiconductor without Light: A New Bacteria-Killing Mechanism Other than Localized Surface Plasmon Resonance or Microbial Fuel Cells. ACS APPLIED MATERIALS & INTERFACES 2016; 8:24509-16. [PMID: 27580379 DOI: 10.1021/acsami.6b10052] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Titania loaded with noble metal nanoparticles exhibits enhanced photocatalytic killing of bacteria under light illumination due to the localized surface plasmon resonance (LSPR) property. It has been shown recently that loading with Au or Ag can also endow TiO2 with the antibacterial ability in the absence of light. In this work, the antibacterial mechanism of Au-loaded TiO2 nanotubes (Au@TiO2-NT) in the dark environment is studied, and a novel type of extracellular electron transfer (EET) between the bacteria and the surface of the materials is observed to cause bacteria death. Although the EET-induced bacteria current is similar to the LSPR-related photocurrent, the former takes place without light, and no reactive oxygen species (ROS) are produced during the process. The EET is also different from that commonly attributed to microbial fuel cells (MFC) because it is dominated mainly by the materials' surface, but not the bacteria, and the environment is aerobic. EET on the Au@TiO2-NT surface kills Staphylococcus aureus, but if it is combined with special MFC bacteria, the efficiency of MFC may be improved significantly.
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Affiliation(s)
- Guomin Wang
- Department of Physics and Materials Science, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong, China
| | - Hongqing Feng
- Department of Physics and Materials Science, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong, China
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, National Center for Nanoscience and Technology (NCNST) , Beijing 100083, P. R. China
| | - Ang Gao
- Department of Physics and Materials Science, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong, China
| | - Qi Hao
- Department of Physics and Materials Science, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong, China
| | - Weihong Jin
- Department of Physics and Materials Science, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong, China
| | - Xiang Peng
- Department of Physics and Materials Science, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong, China
| | - Wan Li
- Department of Physics and Materials Science, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong, China
| | - Guosong Wu
- Department of Physics and Materials Science, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong, China
| | - Paul K Chu
- Department of Physics and Materials Science, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong, China
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Phitaktim S, Chomnawang M, Sirichaiwetchakoon K, Dunkhunthod B, Hobbs G, Eumkeb G. Synergism and the mechanism of action of the combination of α-mangostin isolated from Garcinia mangostana L. and oxacillin against an oxacillin-resistant Staphylococcus saprophyticus. BMC Microbiol 2016; 16:195. [PMID: 27566110 PMCID: PMC5002192 DOI: 10.1186/s12866-016-0814-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 08/17/2016] [Indexed: 11/17/2022] Open
Abstract
Background Globally, staphylococci have developed resistance to many antibiotics. New approaches to chemotherapy are needed and one such approach could be to use plant derived actives with conventional antibiotics in a synergestic way. The purpose of this study was to isolate α-mangostin from the mangosteen (Garcinia mangostana L.; GML) and investigate antibacterial activity and mechanisms of action when used singly and when combined with oxacillin against oxacillin-resistant Staphylococcus saprophyticus (ORSS) strains. The isolated α-mangostin was confirmed by HPLC chromatogram and NMR spectroscopy. The minimum inhibitory concentration (MIC), checkerboard and killing curve were determined. The modes of action of these compounds were also investigated by enzyme assay, transmission electron microscopy (TEM), confocal microscopic images, and cytoplasmic membrane (CM) permeabilization studies. Results The MICs of isolated α-mangostin and oxacillin against these strains were 8 and 128 μg/ml, respectively. Checkerboard assays showed the synergistic activity of isolated α-mangostin (2 μg/ml) plus oxacillin (16 μg/ml) at a fractional inhibitory concentration index (FICI) of 0.37. The kill curve assay confirmed that the viability of oxacillin-resistant Staphylococcus saprophyticus DMST 27055 (ORSS-27055) was dramatically reduced after exposure to isolated α-mangostin (2 μg/ml) plus oxacillin (16 μg/ml). Enzyme assays demonstrated that isolated α-mangostin had an inhibitory activity against β-lactamase in a dose-dependent manner. TEM results clearly showed that these ORSS-27055 cells treated with this combination caused peptidoglycan and cytoplasmic membrane damage, irregular cell shapes and average cell areas were significantly larger than the control. Clearly, confocal microscopic images confirmed that this combination caused considerable peptidoglycan damage and DNA leakage. In addition, the CM permeability of ORSS-27055 was also increased by this combination of actives. Conclusions These findings provide evidence that isolated α-mangostin alone has not only some activity but also shows the synergistic activity with oxacillin against ORSS-27055. The chromone and isoprenyl structures could play a significant role in its action. This synergistic activity may involve three mechanisms of action. Firstly, potential effects of cytoplasmic membrane disruption and increases permeability. Secondly, inhibit β-lactamase activity. Finally, also damage to the peptidoglycan structure. We proposes the potential to develop a novel adjunct phytopharmaceutical to oxacillin for the treatment of ORSS. Future studies require clinical trials to establish if the synergy reported can be translated to animals and humans.
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Affiliation(s)
- Sineewan Phitaktim
- School of Pharmacology, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
| | - Mullika Chomnawang
- Department of Microbiology, Faculty of Pharmacy, Mahidol University, Rajathevi, Bangkok, Thailand
| | - Kittipot Sirichaiwetchakoon
- School of Pharmacology, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
| | - Benjawan Dunkhunthod
- School of Pharmacology, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
| | - Glyn Hobbs
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Griangsak Eumkeb
- School of Pharmacology, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand.
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Yin S, Rao G, Wang J, Luo L, He G, Wang C, Ma C, Luo X, Hou Z, Xu G. Roemerine Improves the Survival Rate of Septicemic BALB/c Mice by Increasing the Cell Membrane Permeability of Staphylococcus aureus. PLoS One 2015; 10:e0143863. [PMID: 26606133 PMCID: PMC4659618 DOI: 10.1371/journal.pone.0143863] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 11/10/2015] [Indexed: 11/29/2022] Open
Abstract
Staphylococcus aureus is one of the most frequently occurring hospital- and community-associated pathogenic bacteria featuring high morbidity and mortality. The occurrence of methicillin-resistant S. aureus (MRSA) has increased persistently over the years. Therefore, developing novel anti-MRSA drugs to circumvent drug resistance of S. aureus is highly important. Roemerine, an aporphine alkaloid, has previously been reported to exhibit antibacterial activity. The present study aimed to investigate whether roemerine can maintain these activities against S.aureus in vivo and further explore the underlying mechanism. We found that roemerine is effective in vitro against four S. aureus strains as well as in vivo against MRSA insepticemic BALB/c mice. Furthermore, roemerine was found to increase cell membrane permeability in a concentration-dependent manner. These findings suggest that roemerine may be developed as a promising compound for treating S. aureus, especially methicillin-resistant strains of these bacteria.
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Affiliation(s)
- Sunjun Yin
- Department of Pharmacy, Kunming General Hospital of Chengdu Military Region, Kunming, Yunnan, 650500, China
| | - Gaoxiong Rao
- Yunnan University of Traditional Chinese Medicine, Kunming, Yunnan, 650500, China
| | - Jin Wang
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, Shaanxi, 710032, China
| | - Liyang Luo
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, Shaanxi, 710032, China
| | - Gonghao He
- Department of Pharmacy, Kunming General Hospital of Chengdu Military Region, Kunming, Yunnan, 650500, China
| | - Chengying Wang
- Yunnan University of Traditional Chinese Medicine, Kunming, Yunnan, 650500, China
| | - Chaoyu Ma
- Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Xiaoxing Luo
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, Shaanxi, 710032, China
| | - Zheng Hou
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, Shaanxi, 710032, China
- * E-mail: (ZH); (GLX)
| | - Guili Xu
- Department of Pharmacy, Kunming General Hospital of Chengdu Military Region, Kunming, Yunnan, 650500, China
- * E-mail: (ZH); (GLX)
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