1
|
Kinneally T, Danda N, Castellanos M, Emeto T, Weerasooriya S. Outpatient Parenteral Antimicrobial Therapy (OPAT) Program for Infective Endocarditis in North Queensland. Heart Lung Circ 2022. [DOI: 10.1016/j.hlc.2022.06.359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
|
2
|
Cheng S, Nair J, Thomas R, Greenland C, Weerasooriya S. A Prospective Cohort Study Evaluating the Prevalence of Familial Hypercholesterolaemia Amongst Cardiac Inpatients in Far North Queensland. Heart Lung Circ 2022. [DOI: 10.1016/j.hlc.2022.06.470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
|
3
|
Weerasooriya S, Stewart R, Thomas R. Telephone Consultations for Cardiac Outpatients During COVID-19—A Review of Acceptability and Impact. Heart Lung Circ 2021. [DOI: 10.1016/j.hlc.2021.06.440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
4
|
Weerasooriya S, DiScipio KA, Peterson J, Weller SK. The Herpes Simplex Viruses Utilize a Recombination‐Dependent Replication Mechanism to Replicate Viral Genomes. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.04857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
5
|
Danda N, Lander K, Minehan S, Weerasooriya S. 131 Ischemic vs Non-Ischemic Cardiomyopathy Outcomes From Heart Failure Service in North Queensland. Heart Lung Circ 2020. [DOI: 10.1016/j.hlc.2020.09.138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
6
|
Cheng S, Porwal K, Weerasooriya S. 195 A Case Of Mitral Annular Disjunction Presenting With Ventricular Arrhythmia. Heart Lung Circ 2020. [DOI: 10.1016/j.hlc.2020.09.202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
7
|
Hayes O, Gupta A, Weerasooriya S, John B, Eng L. 172 Takotsubo Cardiomyopathy Mimicking ST-Elevation Myocardial Infarction Secondary to Nebulised Adrenaline for Upper Airway Obstruction. Heart Lung Circ 2020. [DOI: 10.1016/j.hlc.2020.09.179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
8
|
Danda N, Win K, Willey H, Greenland C, Weerasooriya S, Saxena P. 287 Aortitis and Aortic Valvulitis from Autoimmune Non-Necrotising Vasculitis. Heart Lung Circ 2020. [DOI: 10.1016/j.hlc.2020.09.294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
9
|
Danda N, Lander K, Minehan S, Weerasooriya S. 143 Outcomes of Indigenous Patients With Heart Failure in North Queensland. Heart Lung Circ 2020. [DOI: 10.1016/j.hlc.2020.09.150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
10
|
Mirzaee S, Halim MA, Wang X, Weerasooriya S. Extracardiac Findings in Coronary CT Angiograms in a Tertiary Hospital. Heart Lung Circ 2016. [DOI: 10.1016/j.hlc.2016.06.540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
11
|
Weerasooriya S, Jasti VP, Bose A, Spratt TE, Basu AK. Roles of translesion synthesis DNA polymerases in the potent mutagenicity of tobacco-specific nitrosamine-derived O2-alkylthymidines in human cells. DNA Repair (Amst) 2015; 35:63-70. [PMID: 26460881 PMCID: PMC4651839 DOI: 10.1016/j.dnarep.2015.09.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 08/30/2015] [Accepted: 09/01/2015] [Indexed: 11/26/2022]
Abstract
The tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent human carcinogen. Metabolic activation of NNK generates a number of DNA adducts including O(2)-methylthymidine (O(2)-Me-dT) and O(2)-[4-(3-pyridyl)-4-oxobut-1-yl]thymidine (O(2)-POB-dT). To investigate the biological effects of these O(2)-alkylthymidines in humans, we have replicated plasmids containing a site-specifically incorporated O(2)-Me-dT or O(2)-POB-dT in human embryonic kidney 293T (HEK293T) cells. The bulkier O(2)-POB-dT exhibited high genotoxicity and only 26% translesion synthesis (TLS) occurred, while O(2)-Me-dT was less genotoxic and allowed 55% TLS. However, O(2)-Me-dT was 20% more mutagenic (mutation frequency (MF) 64%) compared to O(2)-POB-dT (MF 53%) in HEK293T cells. The major type of mutations in each case was targeted T → A transversions (56% and 47%, respectively, for O(2)-Me-dT and O(2)-POB-dT). Both lesions induced a much lower frequency of T → G, the dominant mutation in bacteria. siRNA knockdown of the TLS polymerases (pols) indicated that pol η, pol ζ, and Rev1 are involved in the lesion bypass of O(2)-Me-dT and O(2)-POB-dT as the TLS efficiency decreased with knockdown of each pol. In contrast, MF of O(2)-Me-dT was decreased in pol ζ and Rev1 knockdown cells by 24% and 25%, respectively, while for O(2)-POB-dT, it was decreased by 44% in pol ζ knockdown cells, indicating that these TLS pols are critical for mutagenesis. Additional decrease in both TLS efficiency and MF was observed in cells deficient in pol ζ plus other Y-family pols. This study provided important mechanistic details on how these lesions are bypassed in human cells in both error-free and error-prone manner.
Collapse
Affiliation(s)
| | - Vijay P Jasti
- Department of Chemistry, University of Connecticut, Storrs, CT 06269, United States
| | - Arindam Bose
- Department of Chemistry, University of Connecticut, Storrs, CT 06269, United States
| | - Thomas E Spratt
- Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, PA 17033, United States
| | - Ashis K Basu
- Department of Chemistry, University of Connecticut, Storrs, CT 06269, United States.
| |
Collapse
|
12
|
Mirzaee S, Sganzerla E, Weerasooriya S, Yadav R. Utility of intravascular ultrasound (IVUS) and its immediate impact on decision making on patients undergoing coronary intervention at a tertiary referral centre. Heart Lung Circ 2015. [DOI: 10.1016/j.hlc.2015.06.338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
13
|
Weerasooriya S, Jasti VP, Basu AK. Replicative bypass of abasic site in Escherichia coli and human cells: similarities and differences. PLoS One 2014; 9:e107915. [PMID: 25226389 PMCID: PMC4167244 DOI: 10.1371/journal.pone.0107915] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 08/20/2014] [Indexed: 12/18/2022] Open
Abstract
Abasic [apurinic/apyrimidinic (AP)] sites are the most common DNA damages, opposite which dAMP is frequently inserted (‘A-rule’) in Escherichia coli. Nucleotide insertion opposite the AP-site in eukaryotic cells depends on the assay system and the type of cells. Accordingly, a ‘C-rule’, ‘A-rule’, or the lack of specificity has been reported. DNA sequence context also modulates nucleotide insertion opposite AP-site. Herein, we have compared replication of tetrahydrofuran (Z), a stable analog of AP-site, in E. coli and human embryonic kidney 293T cells in two different sequences. The efficiency of translesion synthesis or viability of the AP-site construct in E. coli was less than 1%, but it was 7- to 8-fold higher in the GZGTC sequence than in the GTGZC sequence. The difference in viability increased even more in pol V-deficient strains. Targeted one-base deletions occurred in 63% frequency in the GZG and 68% frequency in GZC sequence, which dropped to 49% and 21%, respectively, upon induction of SOS. The full-length products with SOS primarily involved dAMP insertion opposite the AP-site, which occurred in 49% and 71% frequency, respectively, in the GZG and GZC sequence. dAMP insertion, largely carried out by pol V, was more efficient when the AP-site was a stronger replication block. In contrast to these results in E. coli, viability was 2 to 3 orders of magnitude higher in human cells, and the ‘A-rule’ was more rigidly followed. The AP-site in the GZG and GZC sequences gave 76% and 89%, respectively, Z→T substitutions. In human cells, targeted one-base deletion was undetectable, and dTMP>dCMP were the next preferred nucleotides inserted opposite Z. siRNA knockdown of Rev1 or pol ζ established that both these polymerases are vital for AP-site bypass, as demonstrated by 36–67% reduction in bypass efficiency. However, neither polymerase was indispensable, suggesting roles of additional DNA polymerases in AP-site bypass in human cells.
Collapse
Affiliation(s)
- Savithri Weerasooriya
- Department of Chemistry, University of Connecticut, Storrs, Connecticut, United States of America
| | - Vijay P. Jasti
- Department of Chemistry, University of Connecticut, Storrs, Connecticut, United States of America
| | - Ashis K. Basu
- Department of Chemistry, University of Connecticut, Storrs, Connecticut, United States of America
- * E-mail:
| |
Collapse
|
14
|
Pednekar V, Weerasooriya S, Jasti VP, Basu AK. Mutagenicity and genotoxicity of (5'S)-8,5'-cyclo-2'-deoxyadenosine in Escherichia coli and replication of (5'S)-8,5'-cyclopurine-2'-deoxynucleosides in vitro by DNA polymerase IV, exo-free Klenow fragment, and Dpo4. Chem Res Toxicol 2014; 27:200-10. [PMID: 24392701 PMCID: PMC3952113 DOI: 10.1021/tx4002786] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
![]()
Reactive
oxygen species generate many lesions in DNA, including R and S diastereomers of 8,5′-cyclo-2′-deoxyadenosine
(cdA) and 8,5′-cyclo-2′-deoxyguanosine (cdG). Herein,
the result of replication of a plasmid containing S-cdA in Escherichia coli is reported. S-cdA was found mutagenic and highly genotoxic. Viability and mutagenicity
of the S-cdA construct were dependent on functional
pol V, but mutational frequencies (MFs) and types varied in pol II-
and pol IV-deficient strains relative to the wild-type strain. Both S-cdA → T and S-cdA → G substitutions
occurred in equal frequency in wild-type E. coli,
but the frequency of S-cdA → G dropped in
pol IV-deficient strain, especially when being SOS induced. This suggests
that pol IV plays a role in S-cdA → G mutations.
MF increased significantly in pol II-deficient strain, suggesting
pol II’s likely role in error-free translesion synthesis. Primer
extension and steady-state kinetic studies using pol IV, exo-free
Klenow fragment (KF (exo–)), and Dpo4 were performed
to further assess the replication efficiency and fidelity of S-cdA and S-cdG. Primer extension by pol
IV mostly stopped before the lesion, although a small fraction was
extended opposite the lesion. Kinetic studies showed that pol IV incorporated
dCMP almost as efficiently as dTMP opposite S-cdA,
whereas it incorporated the correct nucleotide dCMP opposite S-cdG 10-fold more efficiently than any other dNMP. Further
extension of each lesion containing pair, however, was very inefficient.
These results are consistent with the role of pol IV in S-cdA → G mutations in E. coli. KF (exo–) was also strongly blocked by both lesions, but it
could slowly incorporate the correct nucleotide opposite them. In
contrast, Dpo4 could extend a small fraction of the primer to a full-length
product on both S-cdG and S-cdA
templates. Dpo4 incorporated dTMP preferentially opposite S-cdA over the other dNMPs, but the discrimination was only
2- to 8-fold more proficient. Further extension of the S-cdA:T and S-cdA:C pair was not much different.
For S-cdG, conversely, the wrong nucleotide, dTMP,
was incorporated more efficiently than dCMP, although one-base extension
of the S-cdG:T pair was less efficient than the S-cdG:C pair. S-cdG, therefore, has the
propensity to cause G → A transition, as was reported to occur
in E. coli. The results of this study are consistent
with the strong replication blocking nature of S-cdA
and S-cdG, and their ability to initiate error-prone
synthesis by Y-family DNA polymerases.
Collapse
Affiliation(s)
- Varsha Pednekar
- Department of Chemistry, University of Connecticut , Storrs, Connecticut 06269, United States
| | | | | | | |
Collapse
|
15
|
Jayasinghe R, Weerasooriya S, Kapadia N. Non-invasive investigation of chronic stable angina--a practical overview for medical practitioners. Med J Malaysia 2012; 67:236-240. [PMID: 22822658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
How does one decide on the best non-invasive test to investigate stable coronary ischaemia? This is a very common question faced by many medical practitioners. Chronic stable angina is a common presentation encountered in general practitice. Upon clinical assessment and risk stratification the patient needs to be investigated further to confirm the diagnosis. The first investigational modality involves a non-invasive test. It is important that practitioners possess a practical knowledge of the array of different tests that are available so that the best suited one for each patient can be chosen. This article aims to compare the efficacy and accuracy and the practical utility of the different non-invasive tests for coronary ischaemia and aid the practitioner in making sound decisions in this regard.
Collapse
Affiliation(s)
- R Jayasinghe
- Griffith University, Gold Coast Hospital, Queensland, Australia.
| | | | | |
Collapse
|
16
|
Jasti VP, Das RS, Hilton BA, Weerasooriya S, Zou Y, Basu AK. (5'S)-8,5'-cyclo-2'-deoxyguanosine is a strong block to replication, a potent pol V-dependent mutagenic lesion, and is inefficiently repaired in Escherichia coli. Biochemistry 2011; 50:3862-5. [PMID: 21491964 PMCID: PMC3092667 DOI: 10.1021/bi2004944] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
8,5'-Cyclopurines, making up an important class of ionizing radiation-induced tandem DNA damage, are repaired only by nucleotide excision repair (NER). They accumulate in NER-impaired cells, as in Cockayne syndrome group B and certain Xeroderma Pigmentosum patients. A plasmid containing (5'S)-8,5'-cyclo-2'-deoxyguanosine (S-cdG) was replicated in Escherichia coli with specific DNA polymerase knockouts. Viability was <1% in the wild-type strain, which increased to 5.5% with SOS. Viability decreased further in a pol II(-) strain, whereas it increased considerably in a pol IV(-) strain. Remarkably, no progeny was recovered from a pol V(-) strain, indicating that pol V is absolutely required for bypassing S-cdG. Progeny analyses indicated that S-cdG is significantly mutagenic, inducing ~34% mutation with SOS. Most mutations were S-cdG → A mutations, though S-cdG → T mutation and deletion of 5'C also occurred. Incisions of purified UvrABC nuclease on S-cdG, S-cdA, and C8-dG-AP on a duplex 51-mer showed that the incision rates are C8-dG-AP > S-cdA > S-cdG. In summary, S-cdG is a major block to DNA replication, highly mutagenic, and repaired slowly in E. coli.
Collapse
Affiliation(s)
- Vijay P Jasti
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | | | | | | | | | | |
Collapse
|
17
|
Basu AK, Jasti VP, Das RS, Weerasooriya S. Abstract 1328: Replication inhibition and mutagenicity of 8,5’-cyclopurine-2’-deoxynucleosides in Escherichia coli. Cancer Res 2011. [DOI: 10.1158/1538-7445.am2011-1328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
8,5’-Cyclopurine-2’-deoxynucleosides are unique tandem DNA lesions formed by oxidation or ionizing radiation, which are repaired only by nucleotide excision repair. They have been suspected to be responsible for neurodegeneration and other diseases. But their replication properties are little studied. In the current work, we have evaluated replication of a pMS2 plasmid containing a single (5's)-8,5’-cyclo-2’-deoxyadenosine (5's-cdA) or (5's)-8,5’-cyclo-2’-deoxyguanosine (5's-cdG) at a preselected site in Escherichia coli. In the wild type E. coli cells, viability of 5's-cdA and 5's-cdG plasmids dropped to approximately 1% and 0.5%, respectively, relative to control. The viability of each was further reduced in pol II-deficient strain, but it was most pronounced in a pol V-deficient strain, where it dropped ten-fold. By contrast, viability increased 4-7-fold in a pol IV-deficient strain. Upon induction of SOS functions, viability increased ten-fold in the wild type strain. Though less pronounced, viability increased in the other strains as well. We conclude that pol V is necessary for translesion synthesis of the cyclopurines and that it may work cooperatively with pol II, which is also needed for bypass. In addition, it appears that although pol IV competes with the other bypass polymerases, it is inefficient in bypassing these lesions. In the absence of SOS, 5's-cdA-to-G mutations occurred at a low frequency, whereas 5's-cdG-to-A events were detected at a much higher frequency. With SOS, 5's-cdA-to-T and 5's-cdG-to-T were also detected. [Supported by NIEHS grant ES-013324]
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1328. doi:10.1158/1538-7445.AM2011-1328
Collapse
|